CONTINUOUS EXTRUSION APPARATUS

Abstract

Continuous extrusion apparatus has a rotary extrusion wheel fixed to the first end of a shaft so as to rotate therewith about a rotary axis. The wheel has at least one peripheral groove. A shoe extends around at least part of the wheel and co-operates with the peripheral groove(s) so as to define a passageway between the wheel and the shoe. The passageway has an inlet for receipt of material to be extruded. The wheel is rotatable relative to the shoe. An abutment member blocks the passageway so as to obstruct the passage of material. An extrusion die is disposed for receipt of material from the passageway. A mounting arrangement disposed between the wheel and shaft comprises a collet having a first inner tapered surface in abutment with a second inner tapered surface defined by a hub of the shaft. The wheel has a first outer tapered surface in abutment with a second outer tapered surface defined by the hub. A feed abutment member is biased by at least one biasing member so as to compress the material passing to the peripheral groove(s) of the wheel. The shoe is mounted on an adjustable support assembly. A scraper blade is selectively engageable with the wheel. The shoe has a curved surface that has a shape that is substantially fixed and forms a close radial fit with a radially outer surface of the wheel.

Description

The present application is a continuation-in-part of co-pending U.S. patent application Ser. No. 14/417,930, filed Jan. 28, 2015, which is a 371 national phase filing of International PCT Patent Application No. PCT/GB2013/051883, filed Jul. 15, 2013, which claims the priority benefit of Great Britain Patent Application No. 1213501.8, filed Jul. 30, 2012, the contents of all of which are incorporated by reference herein in their entirety.

The present invention relates to continuous extrusion apparatus in which feedstock is continuously extruded using a rotary wheel.

The process of continuous extrusion of metals using a rotary wheel is disclosed in UK Patent No. 1370894 and machines using this process are sold to this day under the trade mark CONFORM™. In the CONFORM™ process a wheel has at least one peripheral groove for receipt of solid or particulate feedstock and is rotated past a stationary shoe towards an extrusion die. The shoe effectively closes a length of the groove and is located to make contact with the feedstock in the groove so as to provide an extrusion chamber. The walls of the peripheral groove provide an area of contact with the feedstock that is greater than that of the shoe so that there is greater friction between the feedstock and the wheel compared to that between the feedstock and the shoe. Thus rotation of the wheel advances the material in the groove relative to the shoe. Immediately adjacent to the shoe there is an abutment that is fixed relative to the wheel and which serves to block the groove thus impeding the passage of the feedstock in the groove. Rotation of the wheel thus drives the feedstock against the abutment, creating significant pressure. The compressive loads developed are so great that the material yields and enters the plastic phase whereupon it flows out through an orifice of the extrusion die that is located adjacent to the abutment, the material thus being extruded in continuous form.

The wheel is mounted on an elongate shaft that is supported for rotation at each end by bearings that incorporate multiple seals for retaining oil and preventing ingress of dirt etc. The wheel is clamped between a pair of discs on the shaft by means of a hydraulic nut (such as, for example, a Pilgrim nut) that is screwed on to one end of the shaft and pressurised to provide the high clamping force required to prevent relative rotation of the wheel and the shaft during the extrusion process.

Machines of this kind have to withstand high forces in a relatively confined space. There are significant radial loads applied to the shaft during extrusion such that it undergoes bending and the clamping discs tend to separate from the wheel below the rotational axis of the shaft but are compressed against the wheel above the rotational axis. This causes significant stress and wear on the clamping discs and the wheel.

For large machines there may be up to 500 kNm of torque and a radial force of over 400 tons.

Moreover, during the extrusion process high temperatures are generated by virtue of the friction and deformation of the material in the wheel, grooves, against the shoe, at the abutment and in the die. During continuous extrusion, these temperatures can be of the order of 400-500° C. if no cooling is provided, particularly at high reduction ratios. Internal cooling passages in the machine carry cooling water towards the wheel, die and abutment but the high mechanical loads that the machine components have to bear means that such passages have to be small in order not to reduce the strength or mechanical integrity of components. This results in small volumetric flow rates therefore relatively low rates of heat dissipation. Moreover, the passages are prone to blockage, which prevents cooling and leads to an increased failure rate in moving components.

The extrusion process causes significant wear on the shoe, the die, the abutment and the wheel. The machine components thus have to be serviced, repaired or replaced relatively frequently (perhaps as much as 50 times a year for apparatus that is continuously operated). Moreover, the extrusion area has to be cleaned regularly.

The arrangement of such machines is such that the wheel is difficult to access for replacement, repair, cleaning or servicing etc. The hydraulic pressure of the clamping nut first has to be released so that the shaft may be withdrawn from the wheel, the clamping discs and the bearings. This process risks dirt passing seals into the bearings and contaminating lubricant. Moreover, disassembly of this kind renders the bearing seals prone to wear or damage. The wheel is then typically hammered out from between the clamping discs, risking further damage, before it is repaired or replaced.

After dismantling the machine in this manner there follows a time-intensive process of reassembly, applying the hydraulic nut clamp and then ensuring the shoe is positioned accurately relative to the wheel. Given that the wheel is clamped between the discs and further obscured by bearings and other supports, visible inspection is not easy. It is thus necessary to follow a laborious process of trial and error to ensure the relative positions of the wheel and shoe are correct, taking into account the thermal expansion of the machine components that occurs during use. More specifically, the shoe is typically positioned relative to the wheel with some sort of marker (e.g. strips of solder wire) disposed between them and the wheel is rotated for a short time period. The shoe is then moved out of the way so as to enable a visual inspection of the compressed marker and a judgement made about whether the positioning of the shoe was correct. Fine adjustment to the shoe position is then made by insertion of appropriate shims.

Application of the correct clamping force using the hydraulic nut is not a straightforward process. A pump is used to apply a predetermined pressure, which has the effect of drawing the shaft along its axis so as to clamp the wheel between the discs. Shims are then inserted so as to take up the slack and the pressure removed so that the shaft relaxes against the shims. Such an operation cannot be performed with great precision and is prone to error. If the clamping force is not large enough the wheel may slip relative to the shaft during the extrusion operation or it may be insufficiently supported such that it may split. If too large a clamping force is applied the shaft may be fractured or unduly strained. The process can only be performed reliably by skilled and experienced users of the machine.

Any excess metal that leaks from the groove of the wheel is scraped off and discarded. This waste material known as “flash” is very hot and must be gathered, baled and compacted for recycling.

It is one object of the present invention to obviate or mitigate the aforesaid disadvantages. It is also an object of the present invention to provide for improved or alternative continuous extrusion apparatus.

According to a first aspect of the present invention there is provided continuous extrusion apparatus comprising: a shaft supported for rotation in a bearing, the shaft having first and second ends; a rotary wheel fixed to the first end of the shaft so as to rotate therewith about a rotary axis, the wheel having at least one peripheral groove; a shoe extending around at least part of the wheel and co-operating with the at least one peripheral groove so as to define a passageway between the wheel and the shoe, the passageway having an inlet for receipt of material to be extruded, the wheel being rotatable relative to the shoe; an abutment member blocking the passageway so as to obstruct the passage of material; an extrusion die disposed for receipt of material from the passageway; a mounting arrangement disposed between the wheel and shaft, the arrangement comprising a mounting member having a first inner tapered surface in abutment with a second inner tapered surface defined by the shaft or a component of the mounting arrangement intermediate the shaft and the wheel; the wheel having a first outer tapered surface in abutment with a second outer tapered surface defined by the shaft or a component of the mounting arrangement that is fixed to the shaft.

The first and second inner tapered surfaces combine to ensure that an axial force applied to the mounting member, such as that provided by clamping, may be translated into a substantially radially outward directed force to support the extrusion wheel and react against oppositely directed radial forces imparted to the wheel during the extrusion process. The inner and outer tapered surfaces may also assist in ensuring accurate axial location of the wheel and facilitate separation of the wheel from the shaft when required. The outer tapered surfaces abut to afford frictional resistance to resist relative rotation of the wheel and shaft during the extrusion process.

The mounting arrangement of the wheel and the location of the wheel at the first end of the shaft means that the shaft deflects less than conventional arrangements. The mounting arrangement provides better strength and stiffness compared to existing designs. The reduced deflection ensures that the wheel runs co-axially with greater accuracy. This reduces the amount of fretting in the wheel and hence reduces maintenance and machining (or otherwise reworking) the wheel to remove the fretted surface.

The inner and outer tapered surfaces are disposed around the rotary axis and may be fully or partly annular. That is, the first and second inner tapered surfaces may each be defined on part of a surface of a frustocone. Similarly, the first and second outer tapered surfaces may each be defined on part of a surface of a frustocone. The surfaces may be defined by a discontinuous annular surface.

The first and second outer tapered surfaces may extend outwards from the rotary axis and the first and second inner tapered surfaces may extend inwards towards the rotary axis, in the direction from the first to the second end of the shaft.

The first and second outer tapered surfaces may extend in the opposite direction to the first and second inner tapered surfaces. The two sets of tapered surfaces are preferably inclined such that they provide a non-locking taper between the respective components, that is the respective components can be disassembled easily by axial separation of the abutting tapered surfaces. The non-locking taper may be provided by the frustocone being inclined at an angle of 7-25° to the rotary axis and more preferably between 14 and 18°. Ideally the angle is 16°.

The first and second outer tapered surfaces may be inclined at an angle of substantially 74° to a plane that is perpendicular to the rotary axis. That is equivalent to the frustocone that the surfaces at least partly define being inclined to the rotary axis at an angle of substantially 16°. The first and second inner tapered surfaces are similarly inclined at an angle of substantially 74° to such a plane but since they extend in the opposite direction to the first and second outer tapered surfaces the angle may be expressed as substantially 106° to said plane.

The mounting member is preferably in the form of a collet that is disposed substantially coaxially with the shaft and wheel. The collet preferably defines a wedge shaped cross-section and is preferably annular.

The collet may have an external surface of substantially constant diameter and an internal surface that defines said first inner tapered surface. The external surface may abut directly or indirectly against an internal surface defined by a bore in or through the wheel. The internal surface of the collet may have a portion that defines a constant diameter. This portion may be supported on a constant diameter portion of a stub shaft of the hub. The stub shaft may comprise the frustoconical portion and the constant diameter portion.

The relative movement of the abutting first and second inner tapered surfaces in the axial direction may urge the collet radially outwards.

The collet is preferably radially resilient. In one embodiment the collet is penetrated by a plurality of slots that extend in a substantially axial direction from at least one end of the collet and serve to provide the radial resilience in the collet. The slots may comprise a first group of slots and a second group of slots, the first group of slots being angularly spaced relative to one another and extending in a substantially axial direction from a first end of the collet and the second group of slots being angularly spaced relative to one another and extending in a substantially axial direction from a second end of the collet, the first group of slots being angularly offset from the second group of slots.

The mounting arrangement may further comprise a hub fixed to the shaft. The hub may be a discrete component or may be defined by the shaft such that it is integrally formed therewith (by for example machining the shaft). It may be releasably fixed by means of any suitable fixing means including fasteners such as bolts etc. or by any suitable coupling. Alternatively it may be fixed by a more permanent fixing method such as welding or the like.

The hub may define the second outer tapered surface. In one example the second outer tapered surface is defined by a projection on the hub. The projection may be annular or at least partly annular.

The second inner tapered surface may be defined by the hub. The second inner tapered surface may be substantially or partly annular (e.g. a discontinuous annulus). The second inner tapered surfaced may be defined by a frustoconical portion of the hub.

The second outer tapered surface and the second inner tapered surface may be defined by an annular recess a radial surface of the hub.

The mounting arrangement may further comprise a clamping ring for clamping the wheel to hub. The clamping ring and the wheel may be supported on a plurality of fixing members such as, for example, studs. The fixing members may pass through bores in the wheel. The fixing members may have a first end for fixing to shaft or hub and a second end for fixing to a clamping nut that bears against the clamping ring. The first end of the fixing members may be threaded for screw engagement in a threaded bore in the hub or shaft.

The hub, collet and wheel are preferably coaxially disposed for rotation with the shaft about the rotary axis.

There may be at least one drive coupling between the hub and the wheel, such as for example, a protrusion on one of the hub and wheel for receipt in a recess in the other of the hub and wheel. In one embodiment this is a key and keyway coupling. The keyway may be defined in the wheel and the key defined by the hub, preferably on a radial face thereof. There may be more than one such key and keyway coupling.

The mounting arrangement may further comprise a clamping nut for clamping the mounting member in an axial direction.

At least a portion of the mounting assembly may be disposed within the bearing. In one embodiment the bearing is supported on an external surface of the hub.

There may be provided a lubricant seal for the bearing. The seal may be disposed around the mounting assembly.

The bearing may be supported in a supporting member such as a wall. The bearing may be supported between the second end of the shaft and the wheel. The wheel may be disposed on one side of the wall and a bearing lubrication reservoir may be disposed on the other side of the wall. This provides axial separation of the lubricant from the wheel such that the wheel can be removed from the shaft (for repair, servicing or replacement etc.) without disturbing the lubrication, the bearing or the seal.

The bearing may be disposed at a distance from the rotary axis that is greater than the distance of the wheel from the rotary axis.

A second end of the shaft is preferably connected to a drive. This is preferably on the opposite side of the wall to the wheel.

A cooling chamber may be provided between the shaft and the mounting arrangement. This may be defined by a cavity defined in the shaft or the hub. The shaft may have an internal bore in fluid communication with the cooling chamber. There may be provided a fluid carrying conduit disposed in the internal bore for carrying cooling fluid. The conduit is preferably of smaller diameter than the bore so as to define an annular clearance between the external surface of the conduit and the shaft. In use the annular clearance may provide a return path for the cooling fluid.

A fluid dispersing member such as, for example, a disc may be provide in the chamber for rotation with the shaft. There may be an axial clearance between the fluid dispersing member and an end surface of the chamber. The fluid carrying conduit may have an outlet end that is disposed so as to deliver fluid into the axial clearance.

A specific embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which:

FIG. 1 is a perspective view from one end of a first embodiment of a continuous extrusion apparatus in accordance with the present invention;

FIG. 2 is a second perspective view of the apparatus from the opposite end to that of FIG. 1;

FIG. 3 is an end view of the apparatus of FIGS. 1 and 2, showing a head assembly

FIG. 4 is a cross-section through the head assembly of the apparatus of FIGS. 1 to 3, taken along line A-A of FIG. 3;

FIG. 5 is an exploded perspective view of part of the head assembly of FIG. 4;

FIG. 6 is a sectioned view of a shoe and die assembly of the apparatus of FIGS. 1 to 5;

FIG. 7 is a sectioned view of the of the extrusion wheel of the apparatus of FIGS. 1 to 5, the plane of the section being substantially radial and along line c-c of FIG. 8;

FIG. 8 is a rear end view of the wheel of FIG. 7;

FIG. 9 is a sectioned view of a hub of the head assembly of FIGS. 4 and 5, the sectioned being taken along a radial plane;

FIG. 10 is an end view of the hub in the direction of arrow X of FIG. 9;

FIG. 11 is a sectioned view of a collet of the head assembly of FIGS. 4 and 5, the section being taken through a radial plane;

FIG. 12 is a perspective view from one end of a second embodiment of a continuous extrusion apparatus in accordance with the present invention;

FIG. 13 is a second perspective view of the apparatus from the opposite end to that of FIG. 12;

FIG. 14 is an end view of the apparatus of FIGS. 12 and 13, showing a head assembly;

FIG. 15 is an axial cross-section through the head assembly of the apparatus of FIGS. 12 to 14;

FIG. 16 is an exploded perspective view of part of the head assembly of FIG. 15;

FIG. 17 is a sectioned view of a shoe and die assembly of the apparatus of FIGS. 12 to 16;

FIG. 18 is a sectioned view of the of the extrusion wheel of the apparatus of FIGS. 12 to 17, the plane of the section being substantially radial and along line c-c of FIG. 19;

FIG. 19 is a rear end view of the wheel of FIG. 18;

FIG. 20 is a sectioned view of a hub of the head assembly of FIGS. 15 and 16, the section being taken along a radial plane;

FIG. 21 is an end view of the hub in the direction of arrow X of FIG. 20;

FIG. 22 is a sectioned view of a collet of the head assembly of FIGS. 15 and 16, the section being taken through a radial plane;

FIG. 23A is an enlarged end view of a biasing member of the apparatus of the second embodiment, where the biasing member is in a second position;

FIG. 23B is a view corresponding to that of FIG. 23A but where the biasing member is in a first position;

FIG. 24A shows an enlarged view of the adjustable support shown in FIG. 14, where the adjustable support is in a first configuration;

FIG. 24B shows a view corresponding to that of FIG. 24A but where the adjustable support is in a second configuration (and where a control system is omitted for illustrative purposes);

FIG. 25 shows an enlarged view of a scraper blade assembly of the apparatus of the second embodiment, where the scraper blade is in a first position;

FIG. 26 shows an enlarged view of the scraper blade shown in FIG. 25;

FIG. 27 shows a view corresponding to that of FIG. 25 where the scraper blade is in a second position;

FIG. 28 shows a partial end view of an apparatus according to a third embodiment of the invention, where a shoe of the apparatus is in a first position relative to the wheel, and

FIG. 29 shows a view corresponding to that of FIG. 28 but where the shoe is in a second position relative to the wheel.

Referring now to FIGS. 1 to 3 of the drawings, the exemplary extrusion apparatus comprises a head assembly 10 having an extrusion wheel 11 mounted on an exposed end of a rotary shaft assembly 12 for rotation therewith. The shaft assembly 12 is driven in rotation by a drive assembly 13 that comprises a motor 14 and a belt transmission 15 that drives a pulley 16 connected to the shaft assembly 12 via a reduction gearbox 17. The shaft assembly is supported for rotation by a bearing (hidden in FIGS. 1 to 3) that is located in housing 18.

The wheel 11 has a pair of grooves 19 defined on its outer periphery for receipt of feedstock (not shown) that is delivered via a tangential feeder 20 (visible in FIGS. 2 and 3 only). Immediately above the wheel is a coining roller 21 (visible in FIGS. 2, 3 and 4) by which feedstock from the feeder 20 is urged into the grooves 19. Downstream of the coining roller 21, the periphery of the wheel 11 is covered by a shoe 22 so as to define an extrusion passageway with the grooves 19. For the purposes of clarity the shoe 22 is not shown in FIGS. 1 to 3, but is shown in detail in FIG. 6. However, an adjustable support 23 for positioning the shoe 22 relative to the wheel 11 is shown in FIGS. 2 and 3. The support 23 comprises is substantially L-shaped with a horizontal platform 24, a vertical wall 25 and two adjustable wedges 26, 27. The horizontal platform 24 and vertical wall 25 are adjustable by moving the wedges 26, 27, one wedge being provided for horizontal adjustment of the wall 25 and the other being provided for vertical adjustment of the platform 24. A rotary hand wheel 28, 29 is connected to a respective wedge 26, 27 by an appropriate drive transmission (e.g. a gearbox and a worm and screw drive) for effecting movement of the wedge and therefore adjustment of the shoe position.

The walls of each peripheral groove 19 in the extrusion wheel 11 provide an area of contact with the feedstock that is greater than that of the shoe so that there is greater friction between the feedstock and the wheel compared to that between the feedstock and the shoe. Thus rotation of the extrusion wheel 11 advances the material in the grooves 19 relative to the shoe. Immediately adjacent to the shoe 22 there is an abutment 30 (see FIG. 6) that is fixed relative to the wheel 11 and which serves to block the grooves 19 thus impeding the passage of the feedstock in the grooves 19. Rotation of the wheel 11 thus drives the feedstock against the abutment 30, creating significant pressure. The compressive loads developed are so great that the material yields and enters the plastic phase whereupon it flows out through an orifice of an extrusion die 31 (see FIG. 6) that is located adjacent to the abutment 30, the material thus being extruded in continuous form. In this particular embodiment where there are two peripheral grooves 19, two parallel extrusion dies 31 are provided (only one is shown in FIG. 6). It will be appreciated that in an alternative embodiment only one groove and die may be provided. It is also to be understood that the invention may be applicable to embodiments in which there are more than two peripheral grooves in the wheel.

At the downstream exit of the shoe 22 there is a scraper blade 35 immediately adjacent to the wheel 11 for removing flash from the wheel periphery. The removed flash drops on to a chute 36 from where it is delivered to a suitable receptacle or area for collection.

Referring now to FIG. 4, the head assembly 10 is shown separate from the other components of the apparatus. The rotary shaft assembly 12 comprises a main shaft 37 with a front half that is supported for rotation in a bearing 38 fixed in a front plate 39 of the housing 18, the front half terminating in a mounting assembly 40 by which the wheel 11 is fixed to the shaft 37. A rear half of the shaft extends rearwards of the housing 18 and is supported for rotation in the gearbox 17 (not shown in FIG. 4). The main shaft 37 is penetrated by an internal cooling system that will be described below.

At a location adjacent to the front plate 39 and bearing 38 the external surface of the main shaft 37 has a radially outward extending flange 41 to which the mounting assembly 40 is bolted by a plurality of angularly spaced bolts 41a. The mounting assembly comprises a hub 42, which is coaxially disposed with the main shaft 37, and shown in more detail in FIGS. 5, 9 and 10, a collet 43 disposed between the hub 42 and the wheel 11, a clamping ring 44, studs 45, nuts 46, clamping nut 47 and washer 48.

The hub 42, which is shown in detail in FIGS. 9 and 10, comprises a radially extending front wall 50 from which extends, in the rearwards direction (i.e. towards the shaft), an annular collar 51 whose outer diameter is substantially equal to that of the flange 41. The collar 51 defines a cylindrical cavity 52 and has an end face with threaded bores 53 for receipt of the bolts 41a. The front end of the main shaft 37 is received in the cavity 52 and has an external diameter that is slightly smaller than the internal diameter of the collar 51 such that the hub 42 is supported by the shaft 37 for a short axial length. Extending in the opposite direction from the front wall 50 is a stub shaft 54 for supporting the wheel 11. The stub shaft 54 has a frustoconical portion 55, nearest to the front wall 50, and terminates in a substantially cylindrical portion 56 that bears an external thread.

The main shaft 37 is supported for rotation by the bearing 38, which is concentrically disposed with the hub 42 such that its inner surface is supported on the outer surface of the hub collar 51. The bearing 38, which runs in an oil sump 49, has an annular oil seal housing 57 that extends radially inwards from the front plate 39 of the housing 12, over the front end of the bearing 38. The oil seal housing 57 supports a single lip seal 58 that prevents egression of lubricant from the bearing 38 and ingression of dirt or other contaminants into the bearing 38.

The front wall 50 of the hub 42 has an annular projection 60 defined towards its outer periphery, radially outboard of the frustoconical portion 55 of the stub shaft 54. The projection 60 has an inwardly facing surface 61 that is tapered. The inwardly facing surface 61 of the annular projection 60 and the opposed section of the frustoconical portion 55 of the stub shaft 54 effectively define between them an annular recess 62 with inner and outer tapered side walls 61, 63. In the embodiment shown, the tapered surfaces 61, 63 are inclined relative to the rotation axis by the same amount, one being inclined at a positive angle and the other at a negative angle. It will be seen from FIG. 4 that the annular projection 60 that defines the outer tapered surface of the recess 62 is significantly shorter than the frustoconical portion 55 of the stub shaft 54 so that the inner tapered surface 63 continues beyond the extent of the recess 62.

The annular recess 62 is designed to receive a rear end of the extrusion wheel 11, as is shown in FIG. 4. The front wall 50 of the hub 42 has a pair of keys 64 that project into the annular recess 62 and extend in a substantially radial direction. A corresponding pair of radial keyways 65 (see FIGS. 7 and 8) is defined in a rear face of the extrusion wheel 11 for receipt of the keys 64. The key connection prevents relative rotation of the wheel 11 and the hub 42.

The extrusion wheel 11, which is shown in detail in FIGS. 5, 7 and 8, has a central bore 66 for receipt of the stub shaft 54 and is penetrated by a plurality of axially extending small fixing bores 67. Besides the two grooves 19, the outer periphery has a short taper 68 defined towards the rear end. This taper 68 is complementary to the outer tapered surface 61 defined by the annular projection 60 on the outside of the annular recess 62 in the hub 42 such that when the two are connected together the tapers 61, 68 come into abutment and serve to locate the wheel 11 in the axial direction so that it is aligned with the coining roller 21 and the shoe 22.

The extrusion wheel 11 is supported on the stub shaft 54 by means of the collet 43, which is shown in detail in FIGS. 5 and 11. The collet 43 has a cylindrical outer surface 69 and an interior bore 70 the majority of which is tapered such that the wall of the collet is relatively thin at rear end and is relatively thick at a front end. The bore 70 has a short constant diameter portion at the front end. The wall of the collet is axially slotted to allow it to expand and contract under pressure. A first set of angularly spaced slots 71 extend from the rear end towards the front end but fall short of the front end by an axial distance that is similar to that of the constant diameter portion of the bore 70. Similarly, a second set of angularly spaced axial slots 72, angularly offset from the first set 71, extend from the rear end toward the front end but fall short thereof.

When assembled into the mounting assembly 40, the collet 43 is received in the wheel bore 66 so as to provide radial support between the stub shaft 54 and the extrusion wheel 11. The constant diameter outer surface 69 bears against the internal surface of the extrusion wheel 11 and a tapered internal surface 73 defined by the tapered portion of the bore 70 bears against the frustoconical tapered surface 63 of the stub shaft 54, the tapered surfaces 63, 73 being complementary.

The extrusion wheel 11 is clamped to the hub 42 by means of the annular clamping ring 44 and studs 45 that pass through the small fixing bores 67 in the extrusion wheel 11. Each end of each the studs 45 is threaded, a first end being screwed into a respective threaded bore 74 in the front wall 50 of the hub 42 and the other end being screw connected to a respective nut 46 that is tightened against the clamping ring 44 to clamp the wheel 11 against the hub 42. A separate clamping nut 47 and washer 48 are provided for clamping the collet 42 in place, the nut 47 being screwed on to the thread defined on the cylindrical portion 56 of the stub shaft 54.

In order to assemble the extrusion wheel 11 to the main shaft 37, the studs 45 are first screwed into the threaded bores 74 in the hub 42. The wheel 11 is then offered up to the studs 45 so that they are aligned with the fixing bores 67 in the wheel 11, whereupon the wheel 11 is slid axially towards the hub 42 so that its rear end is received in the annular recess 62. In particular the wheel 11 is positioned in the axial direction such that the tapered surface 68 on the outer periphery of the wheel 11 moves towards the complementary tapered surface 61 of the outer side wall of the annular recess 62. In addition, the keys 64 of the hub 42 are received in the keyways 65 of the wheel so as to provide a positive rotational drive. The collet 42 is then inserted into the radial clearance between the stub shaft 54 and the extrusion wheel 11 such that the tapered inside surface 73 bears against the tapered surface 63 of the frustoconical section 55. The collet 42 is held in place by tightening the clamping nut 47 on to the threaded end 56 of the stub shaft 54 to a predetermined torque. This holds the wheel concentric with the hub. The clamping ring 44 is then located over the studs 45 and secured in place by tightening the nuts 46 so as to secure the axial location of the extrusion wheel 11. The nuts 46 are tightened to pull the wheel 11 on to the hub 42 so that the tapered surfaces 61 and 68 bear against one another. The clamping nut 47 is tightened against the radial face of the front end of the collet 42 and effectively pushes the collet up the frustoconical portion 55 thereby forcing the collet 42 to expand radially outwards, such radial expansion being permitted by the slots 71, 72. This movement forces the outer surface 69 of the collet 42 against the inner surface of the wheel 11 thus providing radial support and ensuring the wheel is located centrally with respect to the rotational axis of the shaft assembly 12. At the same time the tapered surface 68 on the outer periphery of the wheel 11 bears against the complementary tapered surface 61 of the annular projection 60 with greater force. The wheel 11 is thus locked at its inner and outer surfaces.

As the mounting assembly 40 including the hub 42, extrusion wheel 11, collet 42, clamping ring 44 and clamping nut 47, is fixed to the main shaft 37 it rotates with the main shaft 37 as it is driven in rotation by the motor 14, belt 15, pulley 16 and gearbox 17. The extrusion process generates significant radial inward directed and twisting forces. The radial force is reacted by the radial outward force applied by the collet 42 to the extrusion wheel 11 as a result of the application of an axial clamping force at by the clamping ring 44 and nut 47. The twisting force applied to the wheel 11 is reacted by means of the interference at the interface between the outer tapered surfaces 61, 68 and the key connection 64, 65 between the wheel 11 and hub 42.

As will be apparent from an inspection of FIG. 4, the coining roller 21 is located such that its outer periphery is immediately adjacent to the outer periphery of the extrusion wheel 11 so that the feedstock is urged into the peripheral grooves in the wheel. The coining roller 21 is arranged for rotation with a rotary shaft 80 about an axis that is substantially parallel to the axis of rotation of the shaft assembly 12 and extrusion wheel 11.

Referring back to FIG. 4, the main shaft 37 has an internal bore 81 along its length for receipt of a lance 82 that forms part of an internal cooling system for the shaft assembly 12 and head assembly 10. At the rear end of the main shaft 37 the lance 82 is connected to a fixed manifold 83 by means of a rotational coupling 84. The manifold 83 has a first port 85 for delivering water into the lance 82 and a second port 86 for allowing water to exit the cooling system. The opposite end of the lance 82 passes through the cavity 52 in the hub 42 and terminates in a short blind bore 87 provided in the front wall 50. In the cavity 52 there is provided a water distribution member 88 comprising a sleeve 89 fixed to the lance 82 and a thin disc 90 that extends radially outwards direction from the sleeve 89. The disc 90 is axially spaced from the rear face of the front wall 50 of the hub 42 to provide a short axial clearance 91 and the sleeve 89 is penetrated by passages 92 that extend axially in parallel with the axis of rotation and then radially so that the open into the cavity 52. The water-cooling components are shown with the shaft assembly in FIG. 5.

The lance 82 is fixed relative to the main shaft 37 so that it rotates therewith and relative to the manifold 83 by virtue of the rotational coupling 84. The lance 82 has a smaller diameter than the bore 81 so as to afford a small annular clearance with the shaft 37. In operation, cooling water enters the first port 85 in the manifold 83 and passes along the lance 82 to the hub 42 where it emerges in the short blind bore 87. As a result of rotation of the shaft 37 the water is propelled under centrifugal force along the surface of the disc 90 in the axial clearance 91. From there it emerges to fill the cavity 52 and is forced under pressure into the radial portions of the passages 92 defined in the sleeve 89. The water passes into the axial portion of the passages 92 and then into the annular clearance around the outside of the lance 82. After travelling along the bore 81 it reaches the manifold 83 where it egresses through the second port 86.

Referring now to FIG. 6, an exemplary embodiment of a shoe and die assembly 100 is shown in which shoe pressure plates 101 are supported around the wheel 11 (the outer periphery of which is represented in dotted line. An abutment member 30 is designed to extend into each peripheral groove 19 on the wheel 11 and has a shape that is complementary to each groove 19 so as to block the groove but without preventing rotation of the wheel. Immediately above each abutment member 30 there is an outlet aperture 102 defined by a die entry plate 103. Material that is prevented by the abutment member 30 from continuing rotation in each groove 19 is compressed between the wheel and the shoe 22 such that it is transformed into the plastic phase, whereupon it is able to flow out of the outlet aperture 102 to an extrusion die 31. The outlet aperture 102 of the entry plate 103 is disposed immediately adjacent to the abutment member 30 and directs the material away from the wheel 11 in a substantially radial direction. The die 31 is defined in a plate that is supported in a surrounding body 104 and is located at the desired position by multiple packing or spacer plates 105.

As the extrusion wheel 11 rotates the feedstock is forced into the peripheral grooves 19 of the wheel by the coining roller 21 and is then compressed between the pressure plates 101 of the shoe 22 and the surface of the grooves 19. The greater surface area provided by the surface of the wheel that defines the grooves 19 affords greater friction than that of the pressure plates 101 and therefore the material is dragged by the wheel 11 relative to the shoe 22 until it encounters the abutment 30. It will be appreciated that the extrusion process generates significant forces and heat, which the shoe body 104 and the head assembly 10 are designed to withstand.

The tapered surfaces 61, 63, 68, 73 between the wheel 11 and mounting assembly 40 are designed such that the tendency of the wheel to jam on the hub 42 is reduced or eliminated. A non-locking taper of +/−16° (relative to the axis of rotation) is ideal but other angles may be suitable. As can be seen in FIG. 9 the outer tapered surface 61 of the hub 42 subtends an angle of 16° to the rotary axis and the frustocone portion that defines inner tapered surface 63 subtends an angle of 64° to the rotary axis (equivalent to 16° in the opposite direction).

Similarly in FIG. 7 the outer tapered surface 68 defined on the outer periphery of the wheel 11 is represented as 16°. In FIG. 11 the tapered internal surface 73 of the collet 43 is shown having an internal angle of 32°, which is equivalent to an angle of 16° to the rotary axis.

The provision of an extrusion wheel that is mounted at the end of a cantilevered shaft affords many benefits. The inner and outer tapered engagement surfaces 61, 63, 68, 73 between the wheel 11 and the mounting assembly 40 ensures that the forces generated during the extrusion process can be withstood without damage to the wheel 11 or shaft 37.

In particular the provision of a shaft that is supported to one side of the wheel in a bearing 38 in the rigid support provided by the front plate 39 allows the wheel to be disposed at one end of the shaft where it is relative accessible for repair, service, replacement or cleaning etc. Moreover, the cantilevered arrangement ensures that the shaft is not subjected to significant bending as compared to the prior art arrangement.

The key and keyway coupling 64, 65 between the hub 42 and the wheel 11 provide a positive drive coupling that prevents relative rotation of the wheel 11 and shaft 37.

The provision of a collet 42 with a tapered engagement interface 63, 73 with the mounting assembly 40 on the shaft assembly 12 ensures that the radial forces applied to the wheel during extrusion can be reacted. The outer tapered interface 61, 68 between the wheel 11 and the hub 42 of the mounting assembly 40 provides additional resistance to rotational movement of the wheel 11 relative to the shaft 37 and the inner and outer tapered interfaces 61, 63, 68, 73 allow precise axial location of the wheel 11 relative to the shaft 37.

The location of the wheel 11 at one end of the shaft 37 ensures that the bearing 38 and associated seal 58 are not disturbed when accessing the wheel for replacement, repair, cleaning etc. The bearing 38 is located behind the wheel 11 such that it can run in oil sump 39 in the housing 18 and is therefore not prone to overheating.

The accessibility and visibility of the extrusion wheel 11 means that adjustment of the shoe 22 is considerably less laborious and time-consuming. The shoe location is adjusted simply by rotation of the hand wheels 28, 29 to move the adjustment wedge 26.

The fact that the machine is easier to set up with great precision means that there is an increased likelihood of reducing the volume of flash created during the extrusion process.

The location of the wheel at the end of the shaft allows a cooling fluid to be delivered along the shaft to the wheel end. Such a cooling arrangement is not disturbed when removing or servicing the wheel.

It is to be understood that the apparatus of the present invention may be used for any extrudable material. It is particularly suitable for extrusion of copper or aluminium but may be used with any non-ferrous or even ferrous material that is capable of extrusion. It may also be used to extrude plastics materials. In one embodiment the apparatus may be used to co-extrude a coating or sleeve of one material over an extruded core of another material. The sleeve or coating may, for example, be disposed in insulating or heat-resistant plastics-based material and the core may be a material suitable for an electrical conductor.

It will also be appreciated that radial or tangential extrusion dies may be used in the shoe.

It will be appreciated that numerous modifications to the above described design may be made without departing from the scope of the invention as defined in the appended claims. For example, the hub may be defined by machining the shaft such that it is integrally formed with the shaft. Alternatively, it may be a discrete component that is fixed permanently to the shaft by means of, for example, welding.

A further problem with known continuous extrusion apparatus is that the resultant extruded material generally has inconsistent properties, for example a varying grain size.

It is a further object of the present invention to obviate or mitigate this disadvantage.

According to a second aspect of the present invention there is provided a continuous extrusion apparatus comprising a shaft supported for rotation, a rotary extrusion wheel mounted to the shaft so as to rotate therewith about a rotary axis, the wheel having at least one peripheral groove, a feeder for providing material to be extruded to the at least one peripheral groove of the rotary extrusion wheel, a shoe extending around at least part of the wheel and co-operating with the at least one peripheral groove so as to define a passageway between the wheel and the shoe, the passageway having an inlet for receipt of material to be extruded, the wheel being rotatable relative to the shoe, an abutment member blocking the passageway so as to obstruct the passage of material, an extrusion die disposed for receipt of material from the passageway, a feed abutment member arranged to urge the material provided from the feeder into the at least one peripheral groove of the rotary extrusion wheel, wherein the feed abutment member is biased by at least one biasing member so as to compress the material passing from the feeder to the at least one peripheral groove of the rotary extrusion wheel.

This is advantageous in that the compression of the material by the feed abutment member may result in an extruded material that has more uniform properties, for example a more uniform grain size.

Optionally the at least one biasing member is arranged such that the feed abutment member is moved in the radial direction relative to the wheel as the at least one biasing member moves in the radial direction. It will be appreciated that, unless otherwise stated, references to the ‘radial direction’ include a direction having at least a component in the radial direction and do not require that the direction is substantially parallel to the radial direction.

In this regard, optionally the feed abutment member is mounted to a support assembly that is connected to a housing of the apparatus by the at least one biasing member such that as the at least one biasing member moves in the radial direction, the support assembly moves relative to the housing.

The support assembly may be mounted to the housing such that it is rotatable and/or axially moveable relative to the housing as the biasing member is displaced.

The support assembly may be rotatable and/or axially moveable relative to the housing so as to move the feed abutment between a first position in which the feed abutment member is in contact with the wheel and a second position in which the feed abutment member is spaced from the wheel.

Optionally the at least one biasing member is arranged such that the feed abutment member compresses the material, passing from the feeder to the at least one peripheral groove of the extrusion wheel, to a substantially uniform thickness.

In this regard, the at least one biasing member may be arranged to exert a biasing force on the abutment member that is linearly proportional to the displacement of the at least one biasing member caused by contact of the material with the abutment member.

Optionally the feed abutment member is arranged to compress material from the feeder between a surface of the feed abutment member and at least one surface of the rotary extrusion wheel that defines the at least one peripheral groove.

Alternatively the feed abutment member may be arranged to compress material from the feeder between a surface of the feed abutment member and a surface that is not a surface of the rotary extrusion wheel, for example a surface of the apparatus that is downstream of the feeder and upstream of the rotary extrusion wheel.

Optionally the feed abutment member is rotatably mounted to a housing of the continuous extrusion apparatus such that it rotates about an axis as it compresses said material from the feeder. The axis of rotation may be substantially parallel to the rotary axis of the extrusion wheel.

The at least one biasing member may comprise a piston slidably received in a housing, the piston having an end surface, a chamber being defined between the end surface of the piston and an internal surface of a housing, the chamber containing a fluid that is compressed by the piston as the piston moves relative to the housing such that the volume of the chamber is reduced, thereby exerting a force on the piston. The fluid may be any suitable fluid, including air or a hydraulic fluid. In this regard, the at least one biasing member may comprise a hydraulic or pneumatic cylinder.

Optionally the at least one biasing member comprises a resiliently deformable biasing member. In this regard the at least one biasing member may comprise a spring. For example the at least one biasing member may comprise a linear spring, a rotational spring (e.g. a coil spring) or a leaf spring.

The feed abutment member may be freely rotatable. Alternatively, the feed abutment member may be coupled to an actuator that drivably rotates the feed abutment member.

The feed abutment member may have a substantially arcuate cross-sectional shape and be arranged to rotate about a longitudinal axis. The feed abutment member may have a substantially circular cross-sectional shape. The feed abutment member may be substantially cylindrical. The feed abutment member may be a roller or wheel.

Optionally the feeder is arranged to provide said material in a direction that is substantially tangential to the radial periphery of the rotary extrusion wheel at the point at which the material is fed to the extrusion wheel.

Optionally the at least one peripheral groove comprises a pair of peripheral grooves and the feed abutment member is arranged to urge the material fed from the feeder into both peripheral grooves of the rotary extrusion wheel.

The at least one biasing member may comprise a pair of said biasing members.

Optionally the shaft is supported for rotation in a bearing, the shaft having first and second ends; the rotary extrusion wheel is fixed to a first end of the shaft so as to rotate therewith about said rotary axis, a mounting arrangement is disposed between the wheel and shaft, the arrangement comprising a mounting member having a first inner tapered surface in abutment with a second inner tapered surface defined by the shaft or a component of the mounting arrangement intermediate the shaft and the wheel, the wheel having a first outer tapered surface in abutment with a second outer tapered surface defined by the shaft or a component of the mounting arrangement that is fixed to the shaft.

According to a third aspect of the invention there is provided a method of use of a continuous extrusion apparatus comprising a shaft supported for rotation, a rotary extrusion wheel mounted to the shaft so as to rotate therewith about a rotary axis, the wheel having at least one peripheral groove, a feeder for providing material to be extruded to the at least one peripheral groove of the rotary extrusion wheel, a feed abutment member biased by at least one biasing member, a shoe extending around at least part of the wheel and co-operating with the at least one peripheral groove so as to define a passageway between the wheel and the shoe, the passageway having an inlet for receipt of material to be extruded, the wheel being rotatable relative to the shoe, an abutment member blocking the passageway so as to obstruct the passage of material and an extrusion die disposed for receipt of material from the passageway, wherein the method comprises the feed abutment member urging the material from the feeder into the at least one peripheral groove of the rotary extrusion wheel, said material being compressed by the feed abutment member due to the biasing of the feed abutment member by the at least one biasing member, and the extrusion wheel being rotated relative to the shoe such that the material is urged through the passageway and is compressed against an abutment member blocking the passageway such that it yields and passes to an extrusion die.

According to a fourth aspect of the invention there is provided a method of manufacture of an extruded product comprising rotating an extrusion wheel relative to a shoe, that extends around at least part of the wheel and co-operates with at least one peripheral groove in the wheel so as to define a passageway between the wheel and the shoe, the material from the feeder being urged by a feed abutment member into the at least one peripheral groove of the rotary extrusion wheel and said material being compressed by the feed abutment member, due to a biasing of the feed abutment member by at least one biasing member, the extrusion wheel being rotated relative to the shoe such that the material is urged through the passageway, said material being compressed against an abutment member blocking the passageway such that it yields and passes to an extrusion die.

The method of manufacture of the fourth aspect of the invention may be carried out by the continuous extrusion apparatus of the second aspect of the invention.

According to a fifth aspect of the invention there is provided an extruded product made by the method of the third or fourth aspects of the invention.

A further problem with known continuous extrusion apparatus is that it is difficult to position the shoe in a desired accurate position relative to the wheel.

It is a further object of the present invention to obviate or mitigate this disadvantage.

According to a sixth aspect of the invention there is provided a continuous extrusion apparatus comprising a shaft supported for rotation, a rotary extrusion wheel mounted to the shaft so as to rotate therewith about a rotary axis, the wheel having at least one peripheral groove, a feeder for providing material to be extruded to the at least one peripheral groove of the rotary extrusion wheel, a shoe extending around at least part of the wheel and co-operating with the at least one peripheral groove so as to define a passageway between the wheel and the shoe, the passageway having an inlet for receipt of material to be extruded, the wheel being rotatable relative to the shoe, an abutment member blocking the passageway so as to obstruct the passage of material, an extrusion die disposed for receipt of material from the passageway, wherein the shoe is mounted to an adjustable support assembly for positioning the shoe relative to the wheel, the adjustable support assembly being arranged to adjust the position of the shoe relative to the wheel along first and second axes that are inclined relative to each other.

This is advantageous in that being able to adjust the position of the shoe relative to the wheel along first and second axes that are inclined relative to each other allows the shoe to be positioned relative to the wheel more accurately than in conventional arrangements.

Furthermore, the shoe can be positioned visually.

The first and second axes may be substantially perpendicular to each other. Alternatively, the first and second axes may be inclined at an oblique angle relative to each other.

Optionally the adjustable support assembly is arranged such that the position of the shoe relative to the wheel may be varied along said first and second axes independently. In this regard, optionally the position of the shoe relative to the wheel may be varied along said first axis without varying the position of the shoe relative to the wheel along said second axis and vice versa.

Optionally the adjustable support assembly comprises a first adjustment assembly that is moveable in said first axial direction relative to the shoe and is coupled to a housing such that as it moves in said first axial direction relative to the shoe it moves in said second axial direction and wherein the first adjustment assembly is coupled to the shoe such that as the first adjustment assembly moves in the second axial direction, the shoe is moved in said second axial direction and a second adjustment assembly that is moveable in said second axial direction relative to the shoe and is coupled to a housing such that as it moves in said second axial direction relative to the shoe it moves in said first axial direction and wherein the second adjustment assembly is coupled to the shoe such that as the second adjustment assembly moves in the first axial direction, the shoe is moved in said first axial direction.

Optionally the first and second adjustment assemblies are coupled to each other such that movement of the first adjustment assembly in the second axial direction does not move the second adjustment assembly in the second axial direction and movement of the second adjustment assembly in the first axial direction does not move the first adjustment assembly in the first axial direction. In this regard, optionally the first adjustment assembly is slidably mounted relative to the second adjustment assembly in the second axial direction and the second adjustment assembly is slidably mounted relative to the first adjustment assembly in the first axial direction.

Optionally the first adjustment assembly comprises a first formation that is slidably engageable with a first formation of the shoe, or of an intermediary member attached to the shoe. Optionally the first formation of the first adjustment assembly is a protrusion and the first formation of the shoe, or of an intermediary member attached to the shoe, is a groove, channel or slot within which the protrusion is slidably mounted or vice versa. The intermediary member may be a frame member attached to the shoe.

Optionally the first adjustment assembly comprises a first adjustment member that is slidable in said first axial direction relative to the wheel and a coupling member that is fixedly attached to the first adjustment member, wherein the first formation is provided in, or on, the coupling member. The coupling member may be a plate.

Optionally the second adjustment assembly comprises a second formation that is slidably engageable with a second formation of the shoe, or of an intermediary member attached to the shoe. Optionally the second formation of the second adjustment assembly is a protrusion and the second formation of the shoe, or of an intermediary member attached to the shoe, is a groove, channel or slot within which the protrusion is slidably mounted or vice versa. The intermediary member may be a frame member attached to the shoe.

Optionally the second adjustment assembly comprises a second adjustment member that is slidable in said second axial direction relative to the wheel and a coupling member that is fixedly attached to the second adjustment member, wherein the second formation is provided in, or on, the coupling member. The coupling member may be a plate.

Optionally the first adjustment member comprises a platform having a first surface that is coupled to the shoe such that it is slidable relative to the shoe in the first axial direction but is substantially fixed relative to the shoe in the second axial direction and a second surface that is slidably engageable with a surface of a housing such that as it slides relative to the housing the platform is moved in the second axial direction. The second surface of the platform and/or said surface of the housing may be inclined relative to the first axial direction. The first surface of the platform may be substantially parallel to the first axial direction. The first surface of the platform may be coupled to the shoe by an intermediary member. The intermediary member may be a frame member that is fixedly attached to the shoe.

Optionally the second adjustment member comprises a platform having a first surface that is coupled to the shoe such that it is slidable relative to the shoe in the second axial direction but is substantially fixed relative to the shoe in the first axial direction and a second surface that is slidably engageable with a surface of a housing such that as it slides relative to the housing the platform is moved in the first axial direction. The second surface of the platform and/or said surface of the housing may be inclined relative to the second axial direction. The first surface of the platform may be substantially parallel to the first axial direction. The first surface of the platform may be coupled to the shoe by an intermediary member. The intermediary member may be a frame member that is fixedly attached to the shoe.

The first and/or second platforms may have a general wedge shape.

Optionally the adjustable support assembly is arranged to adjust the position of the same part of the shoe relative to the wheel along said first and second axes. Optionally the adjustable support assembly is arranged to adjust parts of the shoe relative to the wheel, along said first and second axes, that are fixed relative to each other.

Optionally the first and second adjustment assembly is coupled to first and second actuators respectively that are arranged to actuate the first and second adjustment assemblies in the first and second axial directions. The first and second actuators may be pneumatic or hydraulic cylinders, rotary hand wheels, or any suitable type of actuator, including a motor. The first and second actuators may be formed by the same actuator, or different actuators.

The apparatus may comprise a control system that is arranged to control the first and second actuators so as to control the position of the shoe in the first and second axial directions. The control system may be arranged to store at least one position of the shoe in the first and second axial directions to control the first and second actuators to move the shoe to said at least one position when the at least one position is input as a selected position to the control system. The at least one position may be a plurality of positions.

Optionally the shaft is supported for rotation in a bearing, the shaft having first and second ends; the rotary extrusion wheel is fixed to a first end of the shaft so as to rotate therewith about said rotary axis, a mounting arrangement is disposed between the wheel and shaft, the arrangement comprising a mounting member having a first inner tapered surface in abutment with a second inner tapered surface defined by the shaft or a component of the mounting arrangement intermediate the shaft and the wheel, the wheel having a first outer tapered surface in abutment with a second outer tapered surface defined by the shaft or a component of the mounting arrangement that is fixed to the shaft.

According to a seventh aspect of the invention there is provided a method of use of a continuous extrusion apparatus comprising a shaft supported for rotation, a rotary extrusion wheel mounted to the shaft so as to rotate therewith about a rotary axis, the wheel having at least one peripheral groove, a feeder for providing material to be extruded to the at least one peripheral groove of the rotary extrusion wheel, a shoe extending around at least part of the wheel and co-operating with the at least one peripheral groove so as to define a passageway between the wheel and the shoe, the passageway having an inlet for receipt of material to be extruded, the wheel being rotatable relative to the shoe, an abutment member blocking the passageway so as to obstruct the passage of material, an extrusion die disposed for receipt of material from the passageway, wherein the shoe is mounted to an adjustable support assembly for positioning the shoe relative to the wheel, the method comprising using the adjustable support assembly to adjust the position of the shoe relative to the wheel along first and second axes that are inclined relative to each other.

Optionally the method comprises rotating the extrusion wheel such that material fed from the feeder is urged through the at least one peripheral groove in the wheel, said material being compressed against the abutment member such that it yields and passes to the extrusion die.

According to an eighth aspect of the invention there is provided a method of manufacture of an extruded product comprising rotating an extrusion wheel relative to a shoe, that extends around at least part of the wheel and co-operates with at least one peripheral groove in the wheel so as to define a passageway between the wheel and the shoe, the extrusion wheel being rotated relative to the shoe such that the material is urged through the passageway, said material being compressed against an abutment member blocking the passageway such that it yields and passes to an extrusion die, wherein the method comprises using an adjustable support assembly to adjust the position of the shoe relative to the wheel along first and second axes that are inclined relative to each other.

Optionally the adjustable support assembly is used to adjust the position of the shoe relative to the wheel while the extrusion wheel is rotated to extrude material.

Optionally the adjustable support assembly is used to adjust the position of the shoe relative to the wheel before and/or after the extrusion wheel is rotated to extrude material.

According to a ninth aspect of the invention there is provided an extruded product made by the method of the seventh or eighth aspects of the invention.

A further problem with known continuous extrusion apparatus is the accumulation of flash on the wheel during the extrusion process.

It is a further object of the present invention to obviate or mitigate this disadvantage.

According to a tenth aspect of the invention there is provided a continuous extrusion apparatus comprising a shaft supported for rotation, a rotary extrusion wheel mounted to the shaft so as to rotate therewith about a rotary axis, the wheel having at least one peripheral groove, a feeder for providing material to be extruded to the at least one peripheral groove of the rotary extrusion wheel, a shoe extending around at least part of the wheel and co-operating with the at least one peripheral groove so as to define a passageway between the wheel and the shoe, the passageway having an inlet for receipt of material to be extruded, the wheel being rotatable relative to the shoe, an abutment member blocking the passageway so as to obstruct the passage of material, an extrusion die disposed for receipt of material from the passageway, wherein the apparatus further comprises a cutting member that is movable between a first position relative to the wheel in which it scrapes material from the wheel, as the wheel rotates, and a second position in which it is spaced further from the wheel than when it is in the first position.

This is advantageous in that the cutting member may be selectively engaged and disengaged with the wheel as desired. In this regard, during use the cutting member may be moved to the first position to scrape material, such as flash, from the wheel. The cutting member may then be moved to the second position, for example when the wheel is not in use, in order to allow access to the wheel for maintenance purposes.

Optionally when the cutting member is in the second position it does not scrape material from the wheel, as the wheel rotates.

Optionally when the cutting member is in the first position it abuts a radially peripheral surface of the wheel and when the cutting member is in the second position it is spaced from the radially peripheral surface of the wheel.

Optionally the cutting member is rotatably mounted to a housing of the apparatus such that it is rotated between its first and second positions. Alternatively, or additionally, the cutting member may be translated between its first and second positions.

Optionally the cutting member has a cutting surface arranged such that when the cutting member is in the first position, the cutting surface scrapes material from the wheel, as the wheel rotates, the cutting surface extending substantially in a plane that is tangential to the radially outer periphery of the wheel, where the cutting surface contacts the wheel. In this regard, when the cutting member is in the first position, the cutting surface forms contacts the radially outer periphery of the wheel along a cutting line, the cutting line and the tangential direction of the outer peripheral surface of the wheel, along this line, defining a plane that is coplanar with the plane of the cutting surface.

Optionally when the cutting member is in the first position it is disposed downstream of the shoe. Optionally when the cutting member is in the first position it is disposed between the shoe and the feeder.

Optionally the cutting member is a blade.

Optionally the shaft is supported for rotation in a bearing, the shaft having first and second ends; the rotary extrusion wheel is fixed to a first end of the shaft so as to rotate therewith about said rotary axis, a mounting arrangement is disposed between the wheel and shaft, the arrangement comprising a mounting member having a first inner tapered surface in abutment with a second inner tapered surface defined by the shaft or a component of the mounting arrangement intermediate the shaft and the wheel, the wheel having a first outer tapered surface in abutment with a second outer tapered surface defined by the shaft or a component of the mounting arrangement that is fixed to the shaft.

According to an eleventh aspect of the invention there is provided a method of use of a continuous extrusion apparatus comprising a shaft supported for rotation, a rotary extrusion wheel mounted to the shaft so as to rotate therewith about a rotary axis, the wheel having at least one peripheral groove, a feeder for providing material to be extruded to the at least one peripheral groove of the rotary extrusion wheel, a shoe extending around at least part of the wheel and co-operating with the at least one peripheral groove so as to define a passageway between the wheel and the shoe, the passageway having an inlet for receipt of material to be extruded, the wheel being rotatable relative to the shoe, an abutment member blocking the passageway so as to obstruct the passage of material, an extrusion die disposed for receipt of material from the passageway and a cutting member, the method comprising locating the cutting member in a first position relative to the wheel, rotating the extrusion wheel such that material fed from the feeder is urged through the at least one peripheral groove in the wheel, said material being compressed against the abutment member such that it yields and passes through the extrusion die, scraping material from the wheel with the cutting member in the first position, as the wheel rotates, and subsequently moving the cutting member to a second position in which it is spaced further from the wheel than when it is in the first position.

According to a twelfth aspect of the invention there is provided a method of manufacture of an extruded product comprising rotating an extrusion wheel relative to a shoe, that extends around at least part of the wheel and co-operates with at least one peripheral groove in the wheel so as to define a passageway between the wheel and the shoe, the extrusion wheel being rotated relative to the shoe such that the material is urged through the passageway, said material being compressed against an abutment member blocking the passageway such that it yields and passes to an extrusion die, wherein the method comprises scraping material from the wheel with a cutting member in a first position, as the wheel rotates, and subsequently moving the cutting member to a second position in which it is spaced further from the wheel than when it is in the first position.

Optionally the method comprises moving the cutting member from the second position to the first position.

According to a thirteenth aspect of the invention there is provided an extruded product made by the method of the eleventh or twelfth aspects of the invention.

A further problem with known continuous extrusion apparatus is that it is desirable for a curved surface of the shoe to cooperate with a peripheral groove in the wheel to define a passageway in such a way that the extruded material has generally uniform properties.

In order to do this it is currently necessary to form the curved surface of the wheel out of a plurality of surfaces that are inclined relative to each other and are adjustable to approximate the shape of a curve that forms a close radial fit the wheel. However, this is a time consuming and laborious process.

It is a further object of the present invention to obviate or mitigate this disadvantage.

According to a fourteenth aspect of the invention there is provided a continuous extrusion apparatus comprising a shaft supported for rotation, a rotary extrusion wheel mounted to the shaft so as to rotate therewith about a rotary axis, the wheel having at least one peripheral groove, a feeder for providing material to be extruded to the at least one peripheral groove of the rotary extrusion wheel, a shoe extending around at least part of the wheel, wherein when the shoe is in a first position relative to the wheel a curved surface of the shoe co-operates with the at least one peripheral groove so as to define a passageway between the wheel and the shoe, the passageway having an inlet for receipt of material to be extruded, the wheel being rotatable relative to the shoe, an abutment member blocking the passageway so as to obstruct the passage of material, an extrusion die disposed for receipt of material from the passageway, wherein the shoe is moveable between said first position and a second position relative to the wheel in which the curved surface of the wheel is spaced further from the wheel then when the shoe is in the first position and wherein the curved surface of the shoe has a shape that is substantially fixed and, when the shoe is in the first position, forms a close radial fit with a radially outer surface of the wheel.

This is advantageous in that because the shoe is movable between said first and second positions, it may be moved to the first position in order for the apparatus to be used to extrude material. Once the extrusion process is complete, the shoe may be moved to the second position, for example to access the curved surface of the shoe, or the radially outer peripheral surface of the wheel, for maintenance purposes. Alternatively, the shoe may be moved between the first and second positions while the extrusion apparatus is in use.

Because the shoe is arranged such that its curved surface has a shape that is substantially fixed and, when the shoe is in the first position, forms a close radial fit with a radially outer surface of the wheel, it is not necessary to manually adjust the shape of the curved surface of the shoe, to match the radially outer surface of the wheel, before moving it from the second position to the first position.

Optionally the curved surface of the shoe is formed by a single curved surfaces or a plurality of surfaces that cooperate to define a generally curved surface. Said plurality of surfaces may be formed by a plurality of plates. Optionally said plurality of surfaces are inclined relative to each other and are substantially fixed relative to each other. Optionally said plurality of surfaces are rotationally and axially fixed relative to each other.

Optionally the curved surface of the shoe has a diameter that is substantially the same as, or slightly greater than, the diameter of the a radially outer surface of the wheel.

Optionally the shoe is mounted on to an adjustable support assembly that is mounted to a housing of the apparatus such that the shoe is movable between said first and second positions. The support may be mounted to the housing for axial and/or rotational movement relative to the housing. The support may comprise a platform for supporting the shoe.

Optionally the adjustable support assembly is arranged to adjust the position of the shoe relative to the wheel along first and second axes that are inclined relative to each other.

Optionally the shaft is supported for rotation in a bearing, the shaft having first and second ends; the rotary extrusion wheel is fixed to a first end of the shaft so as to rotate therewith about said rotary axis, a mounting arrangement is disposed between the wheel and shaft, the arrangement comprising a mounting member having a first inner tapered surface in abutment with a second inner tapered surface defined by the shaft or a component of the mounting arrangement intermediate the shaft and the wheel, the wheel having a first outer tapered surface in abutment with a second outer tapered surface defined by the shaft or a component of the mounting arrangement that is fixed to the shaft.

This mounting arrangement means that the shaft deflects less than conventional arrangements. This advantageously facilitates the use of a shoe having said curved surface that has a shape that is substantially fixed since the curved surface can be arranged to have a closer radial fit with the radially outer surface of the wheel than would otherwise be possible, since the deflection of the wheel that it has to allow for is lower than in conventional arrangements.

Optionally when the curved surface of the shoe is in the first position, it extends around less than 10% of the circumference of the radially outer surface of the wheel. Optionally when the curved surface of the shoe is in the first position, it extends around greater than 10% of the circumference of the radially outer surface of the wheel. Optionally when the curved surface of the shoe is in the first position, it extends around greater than 20% of the circumference of the radially outer surface of the wheel. Optionally when the curved surface of the shoe is in the first position, it extends around greater than 30% of the circumference of the radially outer surface of the wheel.

According to a fifteenth aspect of the invention there is provided a provided a method of use of a continuous extrusion apparatus comprising a shaft supported for rotation, a rotary extrusion wheel mounted to the shaft so as to rotate therewith about a rotary axis, the wheel having at least one peripheral groove, a feeder for providing material to be extruded to the at least one peripheral groove of the rotary extrusion wheel, a shoe extending around at least part of the wheel, wherein when the shoe is in a first position relative to the wheel a curved surface of the shoe co-operates with the at least one peripheral groove so as to define a passageway between the wheel and the shoe, the passageway having an inlet for receipt of material to be extruded, the wheel being rotatable relative to the shoe, an abutment member blocking the passageway so as to obstruct the passage of material, an extrusion die disposed for receipt of material from the passageway, wherein the shoe is moved between said first position and a second position relative to the wheel in which the curved surface of the wheel is spaced further from the wheel then when the shoe is in the first position and wherein the curved surface of the shoe has a shape that is substantially fixed and, when the shoe is in the first position, forms a close radial fit with a radially outer surface of the wheel.

Optionally the method comprises locating the shoe in said first position relative to the wheel, rotating the extrusion wheel such that material fed from the feeder is urged through the at least one peripheral groove in the wheel, said material being compressed against the abutment member such that it yields and passes through the extrusion die.

Optionally the method comprises moving the shoe from the second position to the first position.

Optionally the shoe is moved between the first and second positions while the extrusion wheel is rotated to extrude material. Optionally the shoe is moved between the first and second positions before and/or after the extrusion wheel is rotated to extrude material.

According to a sixteenth aspect of the invention there is provided a method of manufacture of an extruded product comprising rotating an extrusion wheel relative to a shoe, the shoe being in a first position relative to the wheel such that a curved surface of the shoe co-operates with at least one peripheral groove in the wheel so as to define a passageway between the wheel and the shoe, the extrusion wheel being rotated relative to the shoe such that the material is urged through the passageway, said material being compressed against an abutment member blocking the passageway such that it yields and passes to an extrusion die, wherein the shoe is moved between said first position and a second position relative to the wheel in which the curved surface of the wheel is spaced further from the wheel then when the shoe is in the first position and wherein the curved surface of the shoe has a shape that is substantially fixed and, when the shoe is in the first position, forms a close radial fit with a radially outer surface of the wheel.

According to a seventeenth aspect of the invention there is provided an extruded product made by the method of the fifteenth or sixteenth aspects of the invention.

The continuous extrusion apparatus or methods of any of the above aspects of the invention may have any of the features of any of the other aspects of the invention, in any combination.

Referring to FIGS. 12 to 27 there is shown a second embodiment of a continuous extrusion apparatus according to the present invention. The continuous extrusion apparatus of the second embodiment is identical to that of the first embodiment except for the differences described below. Corresponding features are given corresponding reference numerals.

Referring to FIGS. 12 and 13, the apparatus of the second embodiment differs from that of the first embodiment in that the belt transmission 17 is replaced with a direct in-line motor 114 and gearbox 117. The gearbox may be either conventional or epicyclic. It has a hollow shaft to allow access for cooling water feed at the rear of the machine for the extrusion wheel and the shaft bearings.

The shaft assembly may be driven by any suitable arrangement, including a belt drive, gear box or any other suitable arrangement of an actuator and transmission.

FIGS. 12 to 22 show views corresponding to those of FIGS. 1 to 11 respectively.

Referring to FIGS. 23A and 23B, as with the first embodiment, the continuous extrusion apparatus of the second embodiment comprises a coining roller 21 that is arranged to urge the feedstock dispensed from the feeder 20 into a pair of grooves 19 in the rotary extrusion wheel 11.

The feeder 20 is arranged to provide said feedstock material in a direction that is substantially tangential to the radial periphery of the rotary extrusion wheel 11 at the point at which the material is fed to the extrusion wheel 11.

The coining roller 21 is a substantially cylindrical roller that extends along a longitudinal axis 210 and has an outer peripheral surface 230. The roller 21 is mounted to a shaft 205 such that it rotates with the shaft 205. The shaft 205 extends along the central longitudinal axis 210 of the roller 21.

The shaft 205, and therefore the roller 21, is rotatably mounted to a support assembly 250. In this respect, the support assembly 250 comprises first and second side arms 207 (only the first side arm is shown in FIG. 23A) disposed on opposite axial sides of the coining roller 21.

Each of the first and second side arms 207 is a generally L-shaped member comprising first and second sections 221, 222. The first section 221 extends from a first end to a second end in the radially inward direction. The second section 222 extends in a direction perpendicular to the first section from a first end to a second end that is integrally formed with the first end of the second section 221.

The second end of each first section 221 is provided with a bore 206. Each axially opposed end of the shaft 205 is rotatably mounted within the bores 206 in the first sections 221 of the side arms 207. In this way, the coining roller 21 is rotatably mounted to the support assembly 250 to rotate about said axis 210. As the material dispensed from the feeder passes, and contacts, the roller 21, the roller is rotated about its axis 210. In this regard, the roller 21 is freely rotatable (and is not driven by an actuator).

The second embodiment differs from the first embodiment in that the coining roller 21 is biased in the radially inward direction, relative to the extrusion wheel 11, by a biasing member, in the form of a pneumatic cylinder 201.

The pneumatic cylinder 201 comprises a cylindrical piston 444 and a housing 445 within which the cylindrical piston 444 is slidably received.

A first end of the cylindrical piston 444 is disposed within the housing 445 and a second end of the piston 444 is provided with a lug 213 to which the support assembly 250 is rotatably mounted (as described below).

The first end of the second section 222 of each side arm 207 is provided with a cylindrical bore 211. A pin 212 passes through the bores 211 in the side arms and is received in a bore in the lug 213 at the second end of the piston 444. The pin 212 is rotatably mounted within the bores 211 such that each side arm 207 is rotatable about the pin 212 about an axis 215.

The rotational axes 215 of the side arms 207 are coincident with each other. Accordingly each of the first and second side arms 207 is rotatably mounted to the second end of the piston 444 about a rotational axis 215.

The side arms 207 are also rotatably mounted to a housing 18 of the apparatus about an axis 447 disposed towards the second end of the second section 222, on the opposite side of the coining roller 21 to the axis 215.

In this regard, the second section 222 of each side arm 207 is provided with a bore (not shown) towards its second end that receives a pin 448 that is received in a bore 449 in a housing 18 of the apparatus. The pin 448 is rotatably mounted within the bores in the second sections of the side arms 207 such that each side arm 207 is rotatable about the pin 448 about said axis 447.

The piston 444 has an end surface (not shown). A chamber (not shown) is defined between the end surface of the piston and the internal surface of the housing 445. The chamber contains a resiliently compressible fluid in the form of air, supplied from an air source (not shown). The piston 444 is moveable in the radially inward and outward directions. As the piston 444 moves in the radially inward and outward directions it varies the volume of the chamber.

The air in the chamber acts like a spring to urge the piston 444, and therefore the coining roller 21 in the radially inward direction. The pressure of air in the chamber may be varied to adjust the biasing force on the coining roller 21.

The pneumatic cylinder 201 is disposed at the first end of the second section 222 of the respective side arm 207. As the piston 444 moves in the radially inward and outward directions the support arms 207 rotate about said axis 447 at the second end of the second section 222 of the support arms 207. In this way, as the piston 444 moves in the radially inward and outward directions, the coining roller 21 also moves in the radial inward and outward directions as it pivots about the axis 447. It will be appreciated that, unless otherwise stated, references to the ‘radial direction’ include a direction having at least a component in the radial direction and do not require that the direction is substantially parallel to the radial direction.

The cylinder 201 is arranged to bias the coining roller 21 radially inwardly such that the coining roller 20 compresses the material passing from the feeder 20 to the grooves 19 in the wheel 11. In this respect, the piston 444 urges the coining roller 21 radially inwardly such that the material passing from the feeder 20 to the grooves 19 in the wheel 11 is compressed between the outer peripheral surface 230 of the coining roller 21 and the surface 231 of the extrusion wheel 11 that defines the grooves 19.

As stated above, the piston 444 is moveable in the radial direction. As the material fed from the feeder 22 passes the coining roller 21, it acts to urge the coining roller 21 in the radially outward direction (by rotating it clockwise about the axis 447, when viewed as in FIGS. 23A and 23B). This acts to force the piston 444 in the radially outward direction. This compresses the air in the chamber which exerts an opposing force, in the radially inward direction on the piston 444 and therefore on the coining roller 21 that urges the material into the grooves 19 in the wheel 11.

In this respect, it will be appreciated that the piston 444 exerts a radially inward force on the first end of the second sections 222 which acts to rotate the side arms 207 about said axis 447 in an anti-clockwise direction (when viewed as in FIGS. 23A and 23B). This rotation urges the coining roller 21 in the radially inward direction.

The piston 444 is located, and the pressure of the air in the cylinder, is such that the coining roller 20 compresses the material, passing from the feeder 20 to the grooves of the extrusion wheel, to a substantially uniform thickness.

In this respect, the cylinder 201 is arranged to exert a biasing force on the coining roller 21 that is linearly proportional to the distance that the piston 444 is moved into the housing by contact of the material with the coining roller 21.

This is advantageous in that the compression of the material by the coining roller results in an extruded material that has more uniform properties, for example a more uniform grain size.

The support assembly 205 is movable inwardly and outwardly in the radial direction between a first position, as shown in FIG. 23B and a second position as shown in FIG. 23A.

In this respect, the support assembly 205 is moved to the second position by fully retracting the piston 444 into the housing. This is achieved by sucking the air out of the chamber, which moves the piston 444 to its fully retracted position.

When the support assembly 205 is in the first position it is positioned radially inwardly of when it is in the second position. When the support assembly 205 is in the second position, the coining roller 21 is spaced from the wheel 11 in the radially outward direction. When the support assembly 205 is in the first position, the coining roller 21 is in its ‘use’ position, i.e. the coining roller 21 is in contact with the peripheral surface of the wheel 11. The support assembly 205 is moved to the first position by supplying air to the chamber, which thereby forces the piston 444 in the radially inward direction. When the support assembly is in the first position a valve, disposed between the chamber and the air supply, is closed. This closes the chamber, thereby allowing the air to be compressed by the piston 444, as it moves radially inwardly, to act as said biasing member.

This arrangement advantageously allows the coining roller 21 to be selectively engaged with the wheel 11 as desired. This provides for ease of set up of the apparatus.

In the currently described embodiment the biasing member 201 is a pneumatic cylinder. However, it will be appreciated that any of the biasing member may be of any suitable type. For example the biasing member may be a hydraulic cylinder. The biasing member may be a resiliently deformable member, such as a spring.

In addition, it will be appreciated that the size, position and biasing force of the biasing member 201 may be adjusted accordingly. There may be provided a plurality of said biasing members 201.

In the currently described embodiment the coining roller 21 is arranged to compress material from the feeder 20 between the outer peripheral surface 230 of the coining roller 21 and the surface 231 of the extrusion wheel 11 that defines the grooves 19. Alternatively the coining roller 21 may be arranged to compress material from the feeder 20 between the outer peripheral surface 230 of the coining roller 21 and a surface that is not a surface of the rotary extrusion wheel 11, for example a surface of the apparatus that is downstream of the feeder 20 and upstream of the rotary extrusion wheel 11.

The support assembly 250 may be mounted to the housing 18 such that it is rotatable and/or axially moveable relative to the housing 18 as the piston 444 moves relative to the cylinder housing.

Referring to FIGS. 24A and 24B there is shown an enlarged view of the adjustable support assembly 23 shown in FIG. 14.

In more detail, the adjustable support assembly 23 is arranged to adjust the position of the shoe 22 relative to the wheel 11 along first and second axes 601, 602 that are inclined relative to each other. In this embodiment, the first axis 601 is substantially vertical and the second axis 602 is substantially horizontal.

However, it will be appreciated that the first and second axes 601, 602 may be inclined relative to each other at any oblique angle. In addition, the axes 601, 602 may be inclined relative to the vertical and horizontal directions.

The adjustable support assembly 23 comprises first and second adjustment assemblies 603, 604.

The first adjustment assembly 603 comprises a first wedge 26. The first wedge 26 has a first surface 605 that is substantially parallel to the first axial direction 601 and a second surface 606 that is inclined relative to the first axial direction 601 such that it has a component in the second axial direction 602.

The first wedge 26 is slidably mounted within a first channel 607 in a housing 608 of the apparatus. The channel 607 is defined, on one side, by a surface 609 of the housing 608. The surface 609 is inclined inwardly relative to the first axial direction 601 such that it has a component in the second axial direction 602. The surface 609 is substantially parallel to the second surface 606 of the first wedge 26.

The first wedge 26 is attached to a mounting plate 701 that has a protrusion that is slidably mounted within an elongate slot 702 in the housing. The slot 702 has a longitudinal axis that is substantially parallel to said surface 609 of the housing 608. In this way, the first wedge 26 is slidably mounted in the channel 607 in a direction that has a component in the second axial direction 602.

The first wedge 26 is fixedly attached to a coupling plate 610 by a plurality of fasteners that fasten opposed ends of the coupling plate together and pass through an elongate slot 611 in the first wedge 26. The coupling plate 610 is provided with a protrusion (not shown) that is slidably received within an elongate slot 612 in said wall 25. The elongate slot 612 and extends along a longitudinal axis that is substantially parallel to the first axial direction 601.

The second adjustment assembly 604 comprises a second wedge 27. The second wedge 27 has a first surface 615 that is substantially parallel to the second axial direction 602 and a second surface 616 that is inclined relative to the second axial direction 602 such that it has a component in the first axial direction 601.

The second wedge 27 is slidably mounted within a second channel 617 in the housing 608 of the apparatus. The channel 617 is defined, on one side, by a surface 619 of the housing 608. The surface 619 is inclined inwardly relative to the second axial direction 602 such that it has a component in the first axial direction 601. The surface 619 is substantially parallel to the second surface 616 of the second wedge 27.

The second wedge 27 is attached to a mounting plate 703 that is slidably mounted within an elongate slot 704 in the housing. The slot 704 has a longitudinal axis that is substantially parallel to said surface 619 of the housing 608. In this way, the second wedge 27 is slidably mounted in the channel 617 in a direction that has a component in the first axial direction 601.

The second wedge 27 is fixedly attached to a coupling plate 620 by a plurality of fasteners that fasten opposed ends of the coupling plate together and pass through an elongate slot 621 in the second wedge 27. The coupling plate 620 is provided with a protrusion (not shown) that is slidably received within an elongate slot 622 in said platform 24. The elongate slot 622 and extends along a longitudinal axis that is substantially parallel to the second axial direction 602.

In this embodiment the first and second rotary hand wheels 28, 29 are replaced with first and second hydraulic cylinders 128, 129 respectively. The first and second hydraulic cylinders 128, 129 are arranged to move the first and second wedges 26, 27 along the respective channels 607, 617 by appropriate control of the supply of hydraulic fluid to the cylinders 128, 129. It will be appreciated that any suitable form of actuator may be used, including the rotary handwheels 28, 29 of the previous embodiment, motors, or pneumatic cylinders, for example.

FIGS. 24A and 24B show the adjustable support assembly 23 in first and second configurations.

As the first wedge 26 moves along the channel 607 towards the second wedge 27, from the position shown in FIG. 24A to the position shown in FIG. 24B, i.e., in the first axial direction (it will be appreciated that references to a direction being in the first and second axial directions refers to the direction having at least a component in the first and second axial directions and does not necessarily require that the direction is substantially parallel to the first or second axial directions), its second surface 609 slidably bears against the surface 606 of the housing 608. This causes the first wedge 26 to move inwardly in the second axial direction 602.

As the first wedge 26 moves in the first axial direction 601 it slides relative to the vertical wall 25 by virtue of its slidable coupling to the vertical wall 25, along said slot 612, via the coupling plate 610. However, as the first wedge 26 moves in the first axial direction 610 it moves the vertical wall 25 and therefore the shoe 22 in the second axial direction 602, due to the engagement of the protrusion of the coupling plate 610 in the slot 612.

The vertical wall 25 is fixedly attached to the horizontal platform 24. Therefore, as the vertical wall 25 moves in the second axial direction 602, the horizontal wall 24 is also moved in the second axial direction 602. However, due to the provision of the slot 622 in the horizontal platform 24, the horizontal platform 24 is able to move relative to the second wedge 27. Accordingly, the position of the shoe 22 may be adjusted in the second axial direction 602 independently of the adjustment of its position in the first axial direction 601.

As the second wedge 27 moves inwardly along the channel 617 (i.e. away from the first wedge 26), its second surface 619 slidably bears against the surface 616 of the housing 608. This causes the second wedge 27 to move upwardly in the first axial direction 601.

As the second wedge 27 moves in the second axial direction 602 it slides relative to the horizontal wall 24 by virtue of its slidable coupling to the horizontal wall 24 via the coupling plate 620. However, as the second wedge 27 moves in the first axial direction 601 it moves the horizontal wall 24 and therefore the shoe 22 in the first axial direction 601. The horizontal wall 24 is fixedly attached to the vertical wall 25. Therefore, as the horizontal wall 24 moves in the first axial direction 601, the vertical wall 25 is also moved in the first axial direction 601. However, due to the provision of the slot 612 in the vertical wall 25, the vertical wall 25 is able to move relative to the first wedge 26 in the first axial direction 601. Accordingly, the position of the shoe 22 may be adjusted in the first axial direction 601 independently of the adjustment of its position in the second axial direction 602.

The above arrangement is advantageous in that being able to adjust the position of the shoe 22 relative to the wheel 11 along first and second axes 601, 602 that are inclined relative to each other allows the shoe to be positioned relative to the wheel more accurately.

The shoe 22 may be positioned in this way, using the adjustable support assembly, prior to, or after, the apparatus extruding material, as described above. Furthermore, the shoe 22 may be positioned in this way while the extrusion apparatus is in use.

Furthermore, the shoe 22 can be positioned visually.

It will be appreciated that in a reciprocal arrangement the slots 612, 621 may be provided in the respective coupling plates 610, 620 with protrusions provided on the first and second wedges 26, 27 that slidably received within the slots 612, 621 in the coupling plates 610, 620.

Furthermore, the slots 612, 621 in the vertical and horizontal walls 25, 24 may be provided directly in the shoe 22.

The apparatus further comprises a control system 2003 comprising a control unit 2000 that is arranged to control the first and second hydraulic cylinders 128, 129 so as to control the position of the shoe 22 in the first and second axial directions 601, 602.

The control system 2003 further comprises a memory unit 2001, connected to the control unit 2000, arranged to store at least one position of the shoe 22 in the first and second axial directions. The control system 2003 further comprises an input control 2002, connected to the control unit 2000, by which a user may select a desired position of the shoe 22 in the first and second axial directions, from the memory unit 2001. The control unit 2000 then controls the first and second hydraulic cylinders 128, 129 so as to move the shoe 22 to the selected position in the first and second axial directions 601, 602. The memory unit 2001 stores a plurality of said positions.

The control unit may be programmed to automatically move the shoe 22 to certain positions in the first and second axial directions 601, 602 based on a selected routine from the control input 2002, for example based on selected profiles or end product materials. The memory unit 2001 may store such programmes.

Referring to FIGS. 25 to 27 there is shown an enlarged view of a scraper blade assembly 801 shown in FIG. 14.

The scraper blade assembly 801 comprises said scraper blade 35 and a mounting arm 802 on which the scraper blade 35 is mounted.

A first end of the mounting arm 801 is rotatably mounted to a housing 803 of the apparatus. In this respect, a first end of the mounting of 801 is provided with a bore 804 that is mounted on a cylindrical pin 805 that is rotatably fixed relative to the housing 803. The first end of the mounting arm 801 is rotatably mounted to pin 805 to rotate about an axis 806.

The scraper blade 35 is provided at a second end of the mounting arm 801.

Referring to FIG. 26 there is shown an enlarged view of the scraper blade 35, and a portion of the wheel 11. The scraper blade 35 comprises a cutting surface 36.

The mounting arm 801, and therefore the cutting surface 36 of the scraper blade 35 is movable relative to the wheel 11, about said axis 806, between a first position, as shown in FIGS. 25 and 26 and a second position as shown in FIG. 27.

When the cutting surface 36 is in the first position it abuts the outer peripheral surface 11′ of the wheel 11 and scrapes flash from the wheel 11, as the wheel 11 rotates. When the cutting surface 36 is in the first position it is disposed between the shoe 22 and the feeder 20.

When the cutting surface 36 is in the second position it is spaced from the wheel 11 such that it does not scrape flash from the wheel 11 as the wheel 11 rotates.

This is advantageous in that the cutting surface 36 may be selectively engaged and disengaged with the wheel as desired. In this regard, during use the cutting surface 11 may be moved to the first position to scrape flash from the wheel 11. The cutting surface 36 may then be moved to the second position, for example when the wheel 11 is not in use, in order to allow access to the wheel 11 for maintenance purposes.

Referring to FIG. 26 (in which the wheel 11 is omitted for illustrative purposes) the cutting surface 36 is substantially planar, with the cutting surface extending substantially in a plane 901. When the cutting surface 36 is in the first position, said plane 901 is tangential to the radially outer peripheral surface of the wheel 11, where the cutting surface 36 contacts said surface. In this regard, when the cutting surface 36 is in the first position, the cutting surface 36 contacts the radially outer periphery of the wheel along a cutting line 902, the cutting line 902 and the tangential direction 903 of the outer peripheral surface of the wheel, along this line 903, defining a plane that is coplanar with the plane 901 of the cutting surface 36.

This is advantageous in that it facilitates the engagement of the cutting surface 36 with the radially outer peripheral surface 11′ of the wheel 11 as the cutting surface 36 is moved to its first position from its second position.

Alternatively, or additionally, the mounting arm 801 may be mounted to the housing such that it is axially moveable relative to the housing between the first and second positions.

Referring to FIGS. 28 and 29 there is shown a partial end view of a continuous extrusion apparatus according to a third embodiment of the invention and where the shoe 22 is in a first and second position relative to the wheel 11 respectively.

The continuous extrusion apparatus of this embodiment is identical to the continuous extrusion apparatus shown in FIGS. 12 to 27, except for the differences described below. Corresponding features are given corresponding reference numerals.

The apparatus of this embodiment differs from that shown in FIGS. 12 to 27 in that the shoe 1000 has a curved radially inner surface 1001 that is formed by a single surface, as opposed to from a plurality of surfaces of pressure plates. The curved surface 1001 has a shape that is substantially fixed. In this regard, the curved surface 1001 is not formed from a plurality of surfaces (e.g. pressure plates) whose position relative to each other may be adjusted.

The position of the shoe 1000 is movable between a first position, as shown in FIG. 28 and a second position, as shown in FIG. 29. The position of the shoe 1000 is adjusted in the first and second axial directions 601, 602 by the adjustable support assembly 23 of the preceding embodiment.

When the curved surface 1001 is in the first position it forms a close radial fit with the radially outer surface 1010 of the wheel 11. The curved surface 1001 has a diameter that is substantially the same as, or slightly greater than, the diameter of the radially outer surface 1010 of the wheel.

When the curved surface 1001 is in the second position it is spaced further from the radially outer surface 1010 of the wheel 11 than when the curved surface 1001 is in the first position. In this case, the curved surface 1001 is spaced from the radially outer surface 1010 of the wheel 11.

This is advantageous in that because the shoe 1000 is movable between said first and second positions, it may be moved to the first position in order for the apparatus to be used to extrude material. Once the extrusion process is complete, the shoe 1000 may be moved to the second position, for example to access the curved surface 1001 of the shoe, or the radially outer peripheral surface 1010 of the wheel, for maintenance purposes.

Because the shoe 1000 is arranged such that its curved surface 1001 has a shape that is substantially fixed and, when the shoe 1000 is in the first position, forms a close radial fit with the radially outer surface of the wheel, it is not necessary to manually adjust the shape of the curved surface 1001 of the shoe, to match the radially outer surface of the wheel, before moving it from the second position to the first position.

Furthermore, the shoe may be moved while the extrusion apparatus is in use. The additional advantages provided by the adjustable support assembly 23 described above are also provided. The position of the shoe may be controlled by the control system 2000 of the previous embodiment.

In the currently described embodiments the curved surface of the shoe is formed by a single curved surface. Alternatively, it may be formed by a plurality of surfaces that cooperate to define a generally curved surface. Said plurality of surfaces may be formed by a plurality of plates that are inclined relative to each other and are substantially fixed relative to each other.

In the embodiments shown in FIGS. 12 to 29 the wheel 11 is mounted to the rotary shaft assembly 12 as described for the first embodiment. However, it will be appreciated that in the embodiments shown in FIGS. 12 to 29 the wheel 11 may be mounted to the rotary shaft assembly 12 in any other way.

Any of the features of any of the described embodiments may be combined with any feature of any other embodiment in any way.

The described and illustrated embodiments are to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiments have been shown and described and that all changes and modifications that come within the scope of the inventions as defined in the claims are desired to be protected. It should be understood that while the use of words such as “preferable”, “preferably”, “preferred” or “more preferred” in the description suggest that a feature so described may be desirable, it may nevertheless not be necessary and embodiments lacking such a feature may be contemplated as within the scope of the invention as defined in the appended claims. In relation to the claims, it is intended that when words such as “a,” “an,” “at least one,” or “at least one portion” are used to preface a feature there is no intention to limit the claim to only one such feature unless specifically stated to the contrary in the claim. When the language “at least a portion” and/or “a portion” is used the item can include a portion and/or the entire item unless specifically stated to the contrary.

Claims

1. A continuous extrusion apparatus comprising a shaft supported for rotation, a rotary extrusion wheel mounted to the shaft so as to rotate therewith about a rotary axis, the wheel having at least one peripheral groove, a feeder for providing material to be extruded to the at least one peripheral groove of the rotary extrusion wheel, a shoe extending around at least part of the wheel and co-operating with the at least one peripheral groove so as to define a passageway between the wheel and the shoe, the passageway having an inlet for receipt of material to be extruded, the wheel being rotatable relative to the shoe, an abutment member blocking the passageway so as to obstruct the passage of material, an extrusion die disposed for receipt of material from the passageway, a feed abutment member arranged to urge the material provided from the feeder into the at least one peripheral groove of the rotary extrusion wheel, wherein the feed abutment member is biased by at least one biasing member so as to compress the material passing from the feeder to the at least one peripheral groove of the rotary extrusion wheel.

2. A continuous extrusion apparatus according to claim 1 wherein the at least one biasing member is arranged such that the feed abutment member is moved in the radial direction, relative to the wheel, with the at least one biasing member.

3. A continuous extrusion apparatus according to claim 2 wherein the feed abutment member is mounted to a support assembly that is connected to a housing of the apparatus by the at least one biasing member such that the support assembly is moved relative to the housing with the at least one biasing member.

4. A continuous extrusion apparatus according to claim 1 wherein the at least one biasing member is arranged such that the feed abutment member compresses the material, passing from the feeder to the at least one peripheral groove of the extrusion wheel, to a substantially uniform thickness.

5. A continuous extrusion apparatus according to claim 4 wherein the at least one biasing member is arranged to exert a biasing force on the abutment member that is linearly proportional to the displacement, or deformation, of the at least one biasing member caused by contact of the material with the abutment member.

6. A continuous extrusion apparatus according to claim 1 wherein the feed abutment member is arranged to compress material from the feeder between a surface of the feed abutment member and at least one surface of the rotary extrusion wheel that defines the at least one peripheral groove.

7. A continuous extrusion apparatus according to claim 1 wherein the at least one biasing member comprises a piston slidably received in a housing, the piston having an end surface, a chamber being defined between the end surface of the piston and an internal surface of a housing, the chamber containing a fluid that is compressed by the piston as the piston moves relative to the housing such that the volume of the chamber is reduced, thereby exerting a force on the piston.

8. A continuous extrusion apparatus according to claim 1 wherein the at least one biasing member comprises a resiliently deformable biasing member.

9. A continuous extrusion apparatus according to claim 1 wherein the feed abutment member is rotatably mounted to a housing of the continuous extrusion apparatus such that it rotates about an axis as it compresses said material from the feeder.

10. A continuous extrusion apparatus according to claim 9 wherein the axis of rotation of the feed abutment member is substantially parallel to the rotary axis of the extrusion wheel.

11. A continuous extrusion apparatus according to claim 9 wherein the feed abutment member is freely rotatable.

12. A continuous extrusion apparatus according to claim 9 wherein the feed abutment member has a substantially arcuate cross-sectional shape.

13. A continuous extrusion apparatus comprising a shaft supported for rotation, a rotary extrusion wheel mounted to the shaft so as to rotate therewith about a rotary axis, the wheel having at least one peripheral groove, a feeder for providing material to be extruded to the at least one peripheral groove of the rotary extrusion wheel, a shoe extending around at least part of the wheel and co-operating with the at least one peripheral groove so as to define a passageway between the wheel and the shoe, the passageway having an inlet for receipt of material to be extruded, the wheel being rotatable relative to the shoe, an abutment member blocking the passageway so as to obstruct the passage of material, an extrusion die disposed for receipt of material from the passageway, wherein the shoe is mounted to an adjustable support assembly for positioning the shoe relative to the wheel, the adjustable support assembly being arranged to adjust the position of the shoe relative to the wheel along first and second axes that are inclined relative to each other.

14. A continuous extrusion apparatus according to claim 13 wherein the adjustable support assembly is arranged such that the position of the shoe relative to the wheel may be varied along said first and second axes independently.

15. A continuous extrusion apparatus according to claim 13 wherein the adjustable support assembly comprises a first adjustment assembly that is moveable in said first axial direction relative to the shoe and is coupled to a housing such that as it moves in said first axial direction relative to the shoe it moves in said second axial direction and wherein the first adjustment assembly is coupled to the shoe such that as the first adjustment assembly moves in the second axial direction, the shoe is moved in said second axial direction and a second adjustment assembly that is moveable in said second axial direction relative to the shoe and is coupled to a housing such that as it moves in said second axial direction relative to the shoe it moves in said first axial direction and wherein the second adjustment assembly is coupled to the shoe such that as the second adjustment assembly moves in the first axial direction, the shoe is moved in said first axial direction.

16. A continuous extrusion apparatus according to claim 15 wherein the first and second adjustment assemblies are coupled to each other such that movement of the first adjustment assembly in the second axial direction does not move the second adjustment assembly in the second axial direction and movement of the second adjustment assembly in the first axial direction does not move the first adjustment assembly in the first axial direction. In this regard, optionally the first adjustment assembly is slidably mounted relative to the second adjustment assembly in the second axial direction and the second adjustment assembly is slidably mounted relative to the first adjustment assembly in the first axial direction.

17. A continuous extrusion apparatus according to claim 15 wherein the first adjustment assembly comprises a first adjustment member that is slidable in said first axial direction relative to the wheel and a coupling member that is fixedly attached to the first adjustment member, wherein the first formation is provided in, or on, the coupling member.

18. A continuous extrusion apparatus according to claim 17 wherein the first adjustment member comprises a platform having a first surface that is coupled to the shoe such that it is slidable relative to the shoe in the first axial direction but is substantially fixed relative to the shoe in the second axial direction and a second surface that is slidably engageable with a surface of a housing such that as it slides relative to the housing the platform is moved in the second axial direction.

19. A continuous extrusion apparatus according to claim 15 wherein the second adjustment assembly comprises a second adjustment member that is slidable in said second axial direction relative to the wheel and a coupling member that is fixedly attached to the second adjustment member, wherein the second formation is provided in, or on, the coupling member.

20. A continuous extrusion apparatus according to claim 19 wherein the second adjustment member comprises a platform having a first surface that is coupled to the shoe such that it is slidable relative to the shoe in the second axial direction but is substantially fixed relative to the shoe in the first axial direction and a second surface that is slidably engageable with a surface of a housing such that as it slides relative to the housing the platform is moved in the first axial direction.

21. A continuous extrusion apparatus comprising a shaft supported for rotation, a rotary extrusion wheel mounted to the shaft so as to rotate therewith about a rotary axis, the wheel having at least one peripheral groove, a feeder for providing material to be extruded to the at least one peripheral groove of the rotary extrusion wheel, a shoe extending around at least part of the wheel and co-operating with the at least one peripheral groove so as to define a passageway between the wheel and the shoe, the passageway having an inlet for receipt of material to be extruded, the wheel being rotatable relative to the shoe, an abutment member blocking the passageway so as to obstruct the passage of material, an extrusion die disposed for receipt of material from the passageway, wherein the apparatus further comprises a cutting member that is movable between a first position relative to the wheel in which it scrapes material from the wheel, as the wheel rotates, and a second position in which it is spaced further from the wheel than when it is in the first position.

22. A continuous extrusion apparatus according to claim 21 wherein when the cutting member is in the second position it does not scrape material from the wheel, as the wheel rotates.

23. A continuous extrusion apparatus according to claim 21 wherein when the cutting member is in the first position it abuts a radially peripheral surface of the wheel and when the cutting member is in the second position it is spaced from the radially peripheral surface of the wheel.

24. A continuous extrusion apparatus according to claim 22 wherein the cutting member is rotatably mounted to a housing of the apparatus such that it is rotatable between its first and second positions.

25. A continuous extrusion apparatus according to claim 22 wherein the cutting member has a cutting surface arranged such that when the cutting member is in the first position, the cutting surface scrapes material from the wheel, as the wheel rotates, the cutting surface extending substantially in a plane that is tangential to the radially outer periphery of the wheel, where the cutting surface contacts the wheel.

26. A continuous extrusion apparatus according to claim 25 wherein when the cutting member is in the first position, the cutting surface contacts the radially outer periphery of the wheel along a cutting line, the cutting line and the tangential direction of the outer peripheral surface of the wheel, along this line, defining a plane that is coplanar with the plane of the cutting surface.

27. A continuous extrusion apparatus comprising a shaft supported for rotation, a rotary extrusion wheel mounted to the shaft so as to rotate therewith about a rotary axis, the wheel having at least one peripheral groove, a feeder for providing material to be extruded to the at least one peripheral groove of the rotary extrusion wheel, a shoe extending around at least part of the wheel, wherein when the shoe is in a first position relative to the wheel a curved surface of the shoe co-operates with the at least one peripheral groove so as to define a passageway between the wheel and the shoe, the passageway having an inlet for receipt of material to be extruded, the wheel being rotatable relative to the shoe, an abutment member blocking the passageway so as to obstruct the passage of material, an extrusion die disposed for receipt of material from the passageway, wherein the shoe is moveable between said first position and a second position relative to the wheel in which the curved surface of the wheel is spaced further from the wheel then when the shoe is in the first position and wherein the curved surface of the shoe has a shape that is substantially fixed and, when the shoe is in the first position, forms a close radial fit with a radially outer surface of the wheel.

28. A continuous extrusion apparatus according to claim 27 wherein the curved surface of the shoe has a diameter that is substantially the same as, or slightly greater than, the diameter of the radially outer surface of the wheel.

29. A continuous extrusion apparatus according to claim 27 wherein the shoe is mounted on a support that is mounted to a housing of the apparatus such that the shoe is movable between said first and second positions.

30. A continuous extrusion apparatus according to claim 27 wherein the shaft is supported for rotation in a bearing, the shaft having first and second ends; the rotary extrusion wheel is fixed to a first end of the shaft so as to rotate therewith about said rotary axis, a mounting arrangement is disposed between the wheel and shaft, the arrangement comprising a mounting member having a first inner tapered surface in abutment with a second inner tapered surface defined by the shaft or a component of the mounting arrangement intermediate the shaft and the wheel, the wheel having a first outer tapered surface in abutment with a second outer tapered surface defined by the shaft or a component of the mounting arrangement that is fixed to the shaft.