Abstract: A shutter door assembly assembled primarily from extruded plastic components is provided. The shutter door assembly includes an outer rectangular frame surrounding a pivotally attached vaned panel door. Various side, top, and bottom legs of the frame and door are constructed of a hollow extruded plastic and are securely mounted together to form a rigid, durable shutter door. The resulting shutter door has the general look and feel of an actual wooden door. An after-former device for forming extruded tubes for use in the shutter assembly is also provided. The after-former system mounts to a standard circular extrusion head, and converts a circular tube of extrudant to a desired noncircular shape, such as a rectangular shape. The after-former has a conical conduit, with an entrance aperture having a circular shape for receiving the initial extrudant and an exit aperture having the desired noncircular cross-section.

Abstract: Annularly or helically ribbed or corrugated semi-rigid thermoplastic pipe is modified to have a smooth outer wall. The ribbed or corrugated pipe is passed through a heated sleeve to squash and smooth the outer profile of corrugated pipe or bend over ribs of ribbed pipe and mold a smooth outer skin of the pipe. Apparatus for forming the modified pipe includes a travelling mold tunnel for the production of ribbed or corrugated pipe and a smoothing sleeve downstream thereof. The smoothing sleeve has a heater to heat it sufficiently to mold the smoother outer skin.

Abstract: A method of manufacture of an ultra-high molecular weight polyethylene thin-wall pipe which is uniform in thickness and free from a folded mark. The ultra-high molecular weight polyethylene thin-wall pipe is manufactured by supplying ultra-high molecular weight polyethylene into and melting and kneading, continuously extruding the molten substance of the ultra-high molecular weight polyethylene from a die connected to a screw of the screw extruder to form a cylindrical roughly shaped article, and diametrically expanding the cylindrical roughly extruded article by means of a tapered core and taking up.

Abstract: A flat and nearly mechanically isotropic liquid crystal polymer film (38) can be formed by laminating two continuous biaxially oriented films. A laminate is produced having two thin outer surface portions which are oriented in one direction, and a relatively thick inner portion oriented in a transverse direction. The film may also be formed by passing a polymer through a set of three tubular rotors (30) which are concentric and having surfaces which are concentric and define inner and outer annular polymer flow channels (33, 35) between them. These rotors may rotate in the same or opposite directions. Another way to make the film is with a slit-type die (90) through which a polymer flows in one direction, while a moving band (91) passes continuously in a transverse direction. These ordered-polymer films are useful, for example, in the production of printed circuit boards.

Abstract: Extruded, smooth finished solid sheet or film, which may have a thickness<1 mm, of a thermoplastic plastic (such as polycarbonate) with a glass transition temperature >50.degree. C., which under conditions of orientation displays optical birefringence, may be manufactured into a flat strip with smooth finished surfaces, to yield a strip which has characteristics as follows:optical birefringence path difference less than or equal to 50 nm (single pass);low surface roughness;low variation in thickness;by extrusion of the plastic in a thermoplastic state, through a slot nozzle;wherein during or after the smoothing of the two surfaces one of the surfaces of the strip is cooled to below the glass transition temperature, while the other surface and the predominant part of the interior region of the strip remain in the thermoplastic state and the strip is cooled to below the glass transition temperature, under conditions which minimize the deforming forces on the surfaces of the extruded strip.

Abstract: A process for the continuous or semi-continuous production of cellular plastic from a plastic mass containing a blowing agent and, optionally, other process-regulative substances and additives. The process starts by raw materials to a plastic processing machine and kneading the raw materials in the plastic processing machine under conditions of temperature and pressure which will produce an expanding mass only upon release of pressure. The expanding mass is transferred directly to a cooling zone to produce a continuous mass having high viscosity and rigidity and an approximately flat velocity profile under pressure formed by an upstream-directed pressure component. At varying intervals the plastic mass is transferred to a braking-retaining zone which may be an integral part of the cooling zone for build-up of the upstream-directed pressure component until the pressure in the plastic mass in the zones located upstream is sufficient to prevent expansion of the plastic mass.

Abstract: A method of the device for producing a hollow columnar piece whereby a blend of essentially thermoplastic particles is melted into a billet, introduced into a mold, looped into layers inside the mold, and transformed into a piece, subsequent to which the piece is solidified by cooling and removed. The billet (3) is rotated around its axis and concentric with its face as it is introduced into a mold (4), the mold accommodates a core (20), space is left between the core and the inner surface (6) of the mold, the billet is laid along the circumference of the space, and the billet continues to be introduced into the space until the mold's inner surface and core are uniformly and continuously wet with constituents of the billet.

Abstract: A method of manufacturing a columnar shaped piece formed of a thermoplastic matrix with ancillary pieces of a non-creeping hard material embedded therein and cemented by the plastic matrix. The ancillary pieces are essentially overlapping slabs which are substantially parallel to one another and the axis of the columnar shaped piece. Molten thermoplastic blended with solid slabs is extruded in the form of a billet into one end of an elongate mold and rotated around the inner surface of the mold. The extrusion continues until the inner surface is uniformly covered with constituents of the billet.

Abstract: The present invention is directed to a door weather strip in which the corner portions thereof are integrally formed with straight portions thereof. In order to obtain a predetermined sealing interference, the cross sectional shape of the corner portions of hollow sealing portion and the lip seal of the weather strip is arranged to be longer than that in the straight portion. Alternatively, the sealing portion is raised as to have a predetermined shape when the corners are formed. Said formed shapes are solidified by vulcanization after the weather strip has been plastically deformed before the vulcanization.

Abstract: A calibrating unit for an extruder includes an inner calibrating member, and a plurality of outer calibrating members at least partially surrounding the inner calibrating member and forming a gap therebetween through which a plastic material may be extruded, the plurality of outer calibrating members including a base member and at least a first lateral member. The calibrating unit also includes an integrated joint connecting the first lateral member to the base member. The first integrated joint includes a circular cylindrical hinge pin integrally formed along a longitudinal edge of the first lateral member, and a cylindrical circular bearing shell formed in the base member. The circular cylindrical hinge pin is received within the circular cylindrical bearing shell of the base member so that the first lateral member is rotatably interconnected to the base member.

Abstract: A corrugator for ribbing pipes includes two synchronously circulating chains of mold halves, a guide device for the mold halves having an input zone in which the associated mold halves are brought into engagement with each other, a molding zone in which a central channel is provided for guiding the engaged mold jaws and an output zone in which the mold halves are again separated from each other, as well as return guides for the mold halves on the path between the output and input zones and cooling apparatus for cooling at least the central channel with a coolant. A plurality of hollow profile modules is provided for forming the molding zone, each module being provided with a central cavity for the cooling apparatus and two lateral guide portions. Modules are arranged in pairs joining each other transversely of the production direction of the corrugator, and a plurality of module pairs are arranged adjoining each other in series in the production direction of the corrugator.

Abstract: A bent pipe forming apparatus is provided for extruding and forming a fluid material into an annular member. The apparatus has a central mandrel and a die defining an annular gap between the mandrel and the die. One of the mandrel and the die is supported to move in a direction perpendicular to an axis of the mandrel. The movable mandrel or die is provided, on its outer periphery, with a guide circular surface integral therewith. An inner movable ring having inner and outer circular peripheries eccentric to each other is rotatably fitted on the guide surface. An outer movable ring having inner and outer circular peripheries eccentric to each other is rotatably fitted on the periphery of the inner movable ring. The outer movable ring is provided with an outer circular periphery which is rotatably fitted in a stationary circular guide surface. Driving motors are provided to independently move the inner and outer movable rings.

Abstract: A rotating blade is passed beneath an extruder nozzle and employed to cut tails of viscous materials which have been extruded.

Abstract: Biaxially stretched thermoplastic tubes are made in an apparatus having a plastic extruder, the output of which is controllable on an open-circuit or closed-circuit basis and which has a too head for the extrusion of a highly viscous exiting tubing, a stretching mandrel and a speed-controllable draw-off device. In the region of the run-on part there is disposed a surrounding temperature control bath for controlling the temperature of the tube to the stretching temperature while a cooling bath is disposed in the region of the draw-off part. A Raman spectrometer operating with laser waves is disposed in the zone downstream of the cooling bath. The frequency of the laser waves is adapted to the plastic used and the energy of the laser waves is so adapted to the wall thickness of the tube produced that in addition to the radiated wave scattered or reflected by the plastics, at least one wave corresponding to a Raman spectral line is radiated from the tube.

Abstract: Platelike webs of thermoplastic material are produced by extruding a strip of the thermoplastic material and passing it through a roll unit having a pair of intake rolls upstream of which a bank of the material is formed. The delivery speed is controlled in response to the bearing pressure of the intake rolls.

Abstract: The invention provides a method of extruding a thermoplastic resin pipe wherein the steps of the method are extruding a melt of the thermoplastic resin by a die, and sizing the melt by a cylindrical sizer, in which the outer diameter of a die lip is smaller than the outer diameter of the sized pipe, and the thickness of the die lip is smaller than the thickness of the sized pipe. Take up rate is 50 to 20 m/min. The temperature of the melt in the extruding process is 30.degree. C. to 90.degree. C. above the melting temperature of the melt at an outer pipe diameter from 11 to 114 mm.

Abstract: A process for the production of optically isotropic extrusion films is disclosed. Accordingly in a first process step a thermoplsatic resin is extruded to form a film having a thickness below 600 .mu.m. The second process step entailsa) calendering said film between a ground elastic roller and a high gloss steel roller to produce a film having a high gloss surface and a matt surface, orb) calendering said film between a lacquered elastic roller and a high gloss steel roller to produce a film having high gloss on both surfaces, orc) calendering said film between a ground elastic roller and a high gloss steel roller to produce a film having a high gloss surface and a matt surface, and then coating said matt surface with a melt of said thermoplastic polymer and calendering the resulting coated film between a high gloss steel roller and a ground elastic roller, with the high gloss side of the coated film facing the roller of elastic material.

Abstract: This invention relates to a device for the production of grate constructions. In general, such constructions are manufactured manually by connecting transverse ribs to elongated supporting means by welding. Grate constructions can be manufactured automatically at a single step by means of an extruder known from pipe manufacturing techniques. Chill moulds moving in the production direction are thereby modified in such a manner that the chill moulds comprise at least two moulding spaces communicating with each other by means of conduits.

Abstract: A laminated roller die extension assembly (22) for mounting in a die holder (24) including a grooved die member (32) with a grooved surface (34) and a plate die (44) with a flat surface abutting the grooved surface (34) forming a preformer passage (54) in communication with an opening at a cylindrical surface (26) of the roller die extrusion assembly (22), and the plate die (44) having an indented edge (68) for guiding and shaping a strip applied through the opening onto a roller die (28) which is rotated past the opening.

Abstract: A method of producing round rod formed of thermoplastic material by extrusion is described. The rod, following extrusion, is first heated and then cooled while rotating fully supported on rollers. The rollers impart a concentric outer surface shape to the extruded rods and permit uniform cooling across the entire cross section of the extruded rod.

Abstract: In extrusion apparatus for producing a continuous film of thermoplastic material, either as part of an extrusion coating or laminating process or to cast a continuous film, a chill roll which receives the film directly from the extruder is mounted on a wheeled carriage whereon it can be moved lengthwise into and out of operating relation with the other components of the apparatus without requiring lifting thereof or of other parts of the apparatus. The carriage may be proportioned to move directly between the apparatus in which it is to be used and the floor of the mill, or it may be mounted on a separate wheeled cart on which it is transported to and from the extrusion apparatus. Particularly in the latter case, provision is made for both vertical and lateral adjustment of the base structure on which the carriage is supported in its operating relation with the extruder.

Abstract: The invention concerns apparatus for making corrugated tubing. Mold blocks for formation of a travelling mold tunnel are provided with suction to the mold face by means of communication between suction passages in the mold block and a suction chamber. Each mold block has a channel which slidingly engages a track of the suction chamber to receive suction as the mold blocks travel over the track. Tongue and groove connectors are provided between the channel of each block and the track of the suction chamber and communication surfaces of the tongue and groove connectors to provide suction from the suction chamber to the mold face.

Abstract: A web of thermoplastic material extruded directly into a set of tempering rolls is cooled on its upper and lower surfaces while the interior of the web is kept molten. The partially cooled web is fed onto a converyor on which it is fed to a thermoformer. The web remains on the conveyor until its surface layer in contact with the conveyor is reheated to a thermoformable temperature below that at which the web will stick to the conveyor. Apparatus for feeding a web of thermoplastic material from an extrusion to a thermoformer includes tempering rolls and conveyor means which can be adjusted in their relative positions and to control the length of conveyor means contacted by the web.

Abstract: The invention relates to a process and apparatus for processing elastomeric material in particular plastic, rubber and a mixture thereof in roller-head-apparatus in which the material to be processed is plasticized and homogenized in an extruder, extruded from an extrusion head provided on the extruder and then is led through an aperture formed between two rollers. It is the object of the present invention, with an especially simple extrusion head in a roller-head-apparatus to produce uniform and dimensionally exact sheets or foils of different thicknesses without changing structural parts. The invention achieves this in that material formed in plate form by parallel outlet surfaces of the extruder head is led through an aperture space formed between a concave cylindrical surface of a stationary forming tool and the circumferential surface of one of the rollers of the calender before the material enters the space between the two calender rollers.

Abstract: A fishing line, or just a leader, has a core (11) which is coated by plastic material as it is pulled through an extruder (3) and then a quench bath (4) by a variable speed drive device (9). Very fine control can be exerted by laser devices (11, 12) before and after coating, and adjusting a selection of parameters such as drive speed, extrusion rate, pressure and temperature, and cooling. A double coating may be applied or additives mixed in the extruded plastics which will give a desired floating or sinking characteristic.

Abstract: Apparatus for extending film tube from high density polyethylene biaxially oriented in longitudinal or machine direction as well as in cross machine diameter-increasing direction, and for joining extruded closure strip carried helically on one wall of the tube correspondingly stretched as a result of the biaxial stretching to which the film of the tube is stretched. The closure-strip-carrying, biaxially oriented tube is adapted to be converted into a ribbon sheet form with the closure strip extending as individual closure strip sections across the ribbon sheet form at longitudinally spaced intervals, and adapted for making bags.

Abstract: Method in manufacturing a heat insulated tube includes a tube (17) for conducting fluid and a sheath (12) enclosing said tube, a heat insulating material (15) being disposed between the fluid tube and the sheath. The sheath is being extruded in an angle extruder die (10) while the fluid tube and the heat insulating material enclosing said tube are being fed axially through the angle extruder die as the sheath is being extruded around the heat insulating material. Then the sheath (12) extruded from the angle extruder die is kept spaced from the heat insulating material (15) enclosing the fluid tube (17), over an initial length of the axial movement thereof up to chains of chill molds (13) for imparting to the sheath a corrugated shape by forming the sheath against the chains of chill molds under the influence of negative pressure. The invention also relates to a device in extruders having an angle extruder die (10) for the manufacture of the heat insulated tube.

Abstract: An apparatus for producing a curved tube, the apparatus comprising an extruder for extruding a tube having a wall including a first portion having a thickness, and a second portion diametrically opposite the first portion and having a thickness less than the thickness of the first portion, and rollers for forming the tube into a curve with the first portion being radially outward and with the second portion being radially inward so that the thickness of the first portion becomes substantially equal to the thickness of the second portion.

Abstract: An apparatus for the production of a collagen tube to be used as a vascular prostheses or nerve suture, including a cylindrical tubular spinneret having a feed end for an aqueous solution of collagen gel and a discharge end and a coagulant tube concentrically disposed in the spinneret with all around circumferential clearance and terminating upstream of the discharge wherein a tube of aqueous acid collagen gel is extruded through the clearance around the coagulant tube. The coagulant tube has its inner wall contacted with a coagulating solution emerging therefrom before the tube of aqueous collagen gel reaches the discharge end of the cylindrical tubular spinneret. The discharge end of the tubular spinneret terminates in a bath of coagulating solution and a bed is disposed in the bath to receive the extruded collagen tube from the end of the tubular spinneret. The tubular spinneret is capable of being displaced with respect to the bath.

Abstract: Shaping device and method for shaping extrudable material including at least one extrusion nozzle for feeding extrudable material and being supported in a carrier common to all nozzles, motors for moving either the carrier or a movable support surface for receiving extruded material directly from the nozzles and a programmable computer for controlling the motors.

Abstract: A die spool for the extrusion of thermoplastic materials includes an axially split elongate spool body so as to be separable into first and second spool segments. The spool segments collectively establish the spool body and also define an axially oriented extrusion cavity through which thermoplastic material is conveyed. An alignment system ensures that only a single orientation of the extrusion axis is possible when the die spool is coupled to another similar die spool (or to an extrusion die associated with an extruder). A die spool assembly may therefore be provided which is comprised of a number of individual die spools. Preferably, a decreasing temperature gradient is established within the extrusion cavity of the die spool assembly (as may be accomplished by controllably operating electrical resistive heater elements) so as to at least partially solidify the thermoplastic extrudate therewithin.

Abstract: The present invention is directed to the manufacture of plastic tubing exemplified by corrugated plastic tile and parts related thereto, in which molds for shaping an extrudable plastic material are caused to shuttle linearly forwardly and rearwardly with respect to an extruding source of said plastic material. Sequentially related to linear mold movement is opening and closing mold action, which is correlated to the discharge of plastic material from the extruding source thereof. Provision is also made herein during the course of linear mold movement for parking one or more predetermined molds at a location spaced from the extruding source.

Abstract: A molten film extruded from a slot die onto a take-off drum in a cooling system is first cooled on the circumferential surface of the take-off drum and by the ambient air, is subsequently passed into the water bath of a water trough in which the take-off drum is immersed, and finally is transferred from the water bath of the water trough into a post-cooling water bath, in which the film solidifies to an intermediate film having a desired final temperature of approximately 40.degree. C. When the film leaves the take-off drum, the partially solidified molten film has a mean temperature T.sub.u of between 100.degree. C. and 120.degree. C. For optimization of the dwell time of the molten film in the cooling system and in the post-cooling water bath, the drum diameter D of the take-off drum and the length L of the post-cooling water bath are determined by a specific relationship.

Abstract: The invention relates to an apparatus for calendering a plastic web extruded from a slot die, and a method of operating this apparatus, the apparatus having at least two cooled rolls, which work in conjunction, the plastic web passing through the calendering nip between them. The plastic is particularly a partly crystalline type, notably polypropylene. The slot die is arranged above the first nip, and the plastic web passing through the nip continuously comes off the first roll and passes around the second roll at about 180.degree. or more. Below the nip there is a blowing device for causing cooling gas to impinges along the entire width of the plastic web in the channel between the first roll and the plastic web coming off it.

Abstract: An apparatus for manufacturing a resin tube comprising: (a) a support means; (b) a central support by the support means and extending therefrom; (c) a pair of operating means supported by the central shaft at two separate positions; (d) a plurality of rotatable forming rolls each supported by the operating means at both ends thereof in such a manner that the rotatable forming rolls are arranged circularly around the central shaft and that a cylindrical envelope formed by the rotatable forming rolls has a radius changeable by operation of the operating means; and (e) a plurality of flexible link means each connected between one end of each rotatable forming roll and a driving means for simultaneously rotating the rotatable forming rolls in the same direction at any radius of the envelope. Because of this structure, the apparatus can manufacture a resin tube of any size simply by operating the operating means.

Abstract: An apparatus for continuously producing a heat-shrinkable crosslinked resin tube from a crosslinkable resin is provided, comprising in successive connection, an extruder head for extruding the resin into a hollow tube, a fluid under pressure being introduced into the interior of the tube being extruded, a crosslinking cylinder disposed downstream of the head for heating the tubular resin for crosslinking, a flare die disposed downstream thereof for allowing the tube to expand under the fluid pressure, a cooling cylinder disposed downstream thereof for cooling the tube, a guide for deforming the tube into a flattened form, and rollers for pressing and drawing the tube away from the extruder head, wherein a smooth interior surface free of a substantial gap or step extends continuously from the crosslinking cylinder to the cooling cylinder.

Abstract: According to a method of manufacturing a foamed polypropylene resin sheet of this invention, a composition comprising as a resin component a mixture of 80 to 20 wt % of a crystalline propylene-ethylene block copolymer containing 20 wt % or less of ethylene and having a melt index (MI) of 2 or less and 20 to 80 wt % of a crystalline propylene-ethylene block or random copolymer containing 5 wt % or less of ethylene and having an MI of 6 to 20 or a polypropylene homopolymer having an MI of 6 to 20 is used. A pair of molding roll dies is horizontally arranged at a point separated from the center of an apex of an extrusion foaming die when a foamed sheet is to be extrusion-molded. A distance between the center of the roll and the apex of a base lip is set to fall within a range of (R.sup.2 +25).sup.1/2 to (R.sup.2 +144).sup.1/2 where R is a radius of the molding roll die.

Abstract: An apparatus for the production of reinforced tubes by helical winding of thermoplastic strips and reinforcing members on a rotating mandrel, comprises a dual orifice extrusion die means capable of extruding a plastic strip in several different widths while simultaneously feeding a reinforcing member to the rotating mandrel.

Abstract: An extruded thermoplastic polymer conduit having a conduit wall of substantially uniform crystalline morphology through the entire thickness thereof free of any oriented surface zone is formed by heating to melt the surface zone and cooling to recrystallize the surface zone.

Abstract: An apparatus for making extruded film tube having joined to its inside surface a closure strip extending generally transversely, preferably helically, relative to the axis of the tube and the tube and closure strip being adapted to be converted into a ribbon sheet form with the closure strip extending as individual closure strip sections across the ribbon sheet form at longitudinally spaced intervals, and adapted for making bags.

Abstract: Apparatus for the external support of tubular films of thermoplastic material consists of groups of outwardly curved supporting segments disposed successively in the direction of withdrawal of the tubular film. These supporting segments are adjustable simultaneously and in the same sense to different tubular film diameters, and for their adjusting movement they are each connected with a turning bar which is common to all supporting segment groups and journalled in a supporting frame and with a holding bar aligned parallel thereto which again is common to all supporting segment groups.

Abstract: A method of fabricating a clamp cushion for use with a clamp device for mounting and restraining wires. Uncured resilient material is extruded through an extrusion die to form an extrusion having a raised upper surface on one side and, on the other side, a passageway being defined by longitudinal side walls and cover flaps to accommodate the clamp device. A toothed surface is then pressed into the raised surface of the extrusion to form a plurality of longitudinally spaced transverse nodes.

Abstract: The homogeneity of highly reactive polycondensates is improved in a process involving batch operations in a reactor, followed by extrusion and then cooling by a coolant to the point of solidification after which the polycondensates are milled and removed. The cooling is carried out with a low-boiling liquified gas.

Abstract: Apparatus for preparing extrudable food products prior to cooking includes depositing portions of food product onto a horizontal surface, coating the food portions with flour, vacuuming away excess flour, and incrementally flattening the food portions to a desired thickness. An apparatus for performing this process includes a first flour depositor, a food depositor, a second flour depositor, and a food flattener, all mounted above a conveyor belt. The conveyor belt is mounted atop a supporting chassis which, in addition to providing a mounting base for the components named above, houses the electrical and hydraulic control means for the apparatus. The food depositor comprises conventional extruding means suitable for use with raw dough or ground meat, and a duality of hydraulically activated, high-speed cutter blades. The uniquely designed cutter blades have flattened, essentially planar cutting edge portions which create an aerodynamic shock wave along the line of impact between the blades.

Abstract: Apparatus for making a bottle carrying handle comprising a substantially irregular elongated body which is tubular-shaped configurated at its middle part, the body having at least two ends, each end defining a hook carrying portion formed by a planar surface which is cut in a "U" shape configuration. The cut forms two supporting legs and each lug includes bottle neck retaining means. The apparatus for manufacturing the handle comprises a plurality of moulds and countermoulds, each mould includes a "U" shaped central cavity and each lug of the "U" has a "U" shaped recess. One of the lugs includes an "L" shaped recess which is aligned with respective projections provided in the associated countermould of the set, these projections are spaced apart by small spaces.

Abstract: A stretching device for stretching a tubular film includes a mandrel including a stretching section, a pair of payoff nip rolls disposed upstream of the mandrel and a pair of take-up nip rolls disposed downstream of the mandrel. The stretching section of the mandrel is comprised of a plurality of rings arranged substantially concentrically in spaced-apart relationship in the travelling direction of the tubular film. The outside diameter of a ring on the downstream side is larger than that of a ring on the upstream side. Each of the rings has a plurality of rotating members mounted rotatably, and the plurality of rotating members define an outer circumferential ring edge which is generally smoothly circular.

Abstract: A system for molding elongated ribbon-like products from thermoplastic materials utilizing a plurality of molds which are moved in tandem along a production line. As the molds are moved along the line at successive stations they are, while open, thermally adjusted to a temperature suitable for forming the product to be molded and then a ribbon of plastic is deposited in them. They are then closed and cooled and reopened and the molded product removed. The system utilizes only enough molding pressure to assure distribution of the plastic to all parts of the mold cavity and shaping of the molded product to the geometric design of the mold. The system includes a transfer means for the molds which returns the emptied molds for recycling through the molding process.

Abstract: The invention relates to a method of and a device for simultaneously generating heat energy and oscillation energy. In the method heat is generated by induction heating and oscillations are created by means of at least piezoelectric elements. Previously a resonance circuit formed by a series connection of an inductive component and a capacitive, piezoelectric component has been used for the generation of oscillations only. A disadvantage of this kind of circuit has been that the circuit is difficult to control on account of the narrow resonance region of the piezoelectric element. This advantage is avoided in the solution according to the invention in such manner that one and the same resonance circuit formed by a series connection of an inductive and capacitive element generates both heat energy and oscillation energy.

Abstract: The process for the extrusion of an expandable plastic composition comprising extruding the composition to an at least partially expanded state through a cross section of die with an area essentially the same as that of the entrance to the cooling fixture which defines the shape and dimensions in the final profile to be produced and essentially having the shape of the latter, by leaving a space empty of material within the profile in the course of extrusion through said cross section and then confining the composition thus extruded immediately at the exit from said die cross section and essentially along the extension of the extrusion axis, within a cooled and elongated shaping space, open at both ends along said extrusion axis and having an exit cross section identical to that of the profile to be obtained, the improvement comprising separating said cooled and elongated shaping space into at least two parts separated from one another by a free space, with the first said part not exceeding a few centimeters i

Abstract: A web of molten thermoplastics material (4) from extruder die (3) is fed through a pair of temperature controlled rolls (5) having a gap (13) of width less than that of the web thickness leaving the extruder die (3) and is fed from the rolls (5) directly and continuously under uniform tension to a thermoforming machine (9) (10) as a formable web (6) of substantially uniform temperature through its thickness.