APPARATUS FOR TRANSPORTING FIBRE MATERIAL BETWEEN A DRAFTING DEVICE AND A LOOP-FORMING MACHINE AND A CIRCULAR KNITTING MACHINE EQUIPPED WITH SAID APPARATUS
A device for transporting fibre material between a drawing frame and a loop-forming machine is described. The device contains at least two transport units which are disposed in succession and have respectively one inlet- and outlet opening, said transport units being formed from respectively one twisting member (16a, 16b, 16c) and one transport pipe (17a, 17b, 17c) connected thereto, there being provided between an outlet end (28) of a preceding transport unit (16a, 17a) and the inlet end of a subsequent transport unit (16b, 17b) a gap (27a, 27b) which is intended for forming an air removal opening. According to the invention, a suction device (31a, 31b) is disposed in the region of this gap (27a, 27b) (FIG. 4).
The invention relates to a device of the type indicated in the preamble of claim 1 and to a circular knitting machine equipped therewith.
Devices of this type are known in particular in conjunction with so-called spin-knitting machines, i.e. for example circular knitting machines (PCT WO 2004/079 068 A2, DE 10 2006 006 502 A1) which operate with extensively untwisted fibre materials instead of with normal yarns. The fibre material used for knitting is converted directly after emergence thereof from a drawing frame with the help of a spinning or transport device which has a so-called twisting member into a temporary yarn, the temporary twisting of the fibre material being maintained during the entire transport process. Transport of the temporary yarn is effected preferably in a transport pipe connected to the twisting member. For longer transport paths which are generally desirable, a plurality of transport units which are formed respectively from one twisting member and one transport pipe are connected in succession in order to be able to dispose the drawing frames at a comparatively large distance from the loop-forming machine. For the purpose of achieving a uniform transport of the fibre, it is normal in addition to leave a gap between two successive transport units of this type which serves to dissipate the compressed airflows which are required for producing the twists. Consequently, it is possible, on the one hand, to transport the fibre material, despite its low strength relative to normal yarns, over fairly long stretches from the drawing frame to an assigned system of a loop-forming machine, in particular a circular knitting machine, since it is achieved by this contrivance that the fibre material which is shaped into a temporary yarn meets all strength requirements on the transport path and no danger exists that it detaches or tears. On the other hand, the twists provided for the fibre material in the temporary yarn are again reduced to zero (false twist principle) on the short stretch from the end of the outlet of the transport device to the relevant system of the loop-forming machine so that the fibre material processed into loops does not comprise a twisted yarn but essentially untwisted staple fibres which are disposed parallel to each other. Consequently, a knitted fabric with extreme softness is obtained as end product.
One disadvantage of the described transport resides in the fact that dirt particles, burls, short and foreign fibres and also other foreign bodies which adhere loosely to the fibre material and are entrained with the latter can lead to faults in the knitted fabric and to contamination of the loop-forming members. Differently from normal spinning, no spoolers or the like are present, by means of which impurities and other faults in the fibre material can be recognised and possibly eliminated by cutting up the temporary yarn and subsequent splicing.
Devices of the initially described type have therefore also already been proposed (DE 10 2007 018 369) which have, in the gaps between successive transport units, respectively an air supply member which, with the outlet and inlet openings of the transport units which abut against each other in the gaps, form an essentially closed system and serve, in addition to air removal, above all for cleaning and deflying the fibre material. It is consequently achieved that foreign particles in the region of the gap are trapped and removed from the fibre flow. However it has come to light in practical testing of such a system that essentially only the light particles are removed from the fibre flow, whereas heavier particles, in particular so-called shell parts, remain in the fibre flow and therefore ultimately are included with the fibre material in the knitted fabric. In addition, the downside of this type of cleaning is that the entire transport stretch from the drawing frame to the loop-forming machine forms not only a closed system but also one which is rigid and not particularly flexible, said system being connected to an additional collecting line and being able to impede operations at the loop-forming machine.
Confronting this, the technical problem of the present invention resides in configuring the initially described device such that it can be handled more easily, can be adapted more easily to the requirements of the individual case and enables even more effective cleaning of the fibre flow.
This problem is resolved according to the invention in that a suction device is disposed in the region of the open gap which forms the air removal opening.
It was established surprisingly that the suction device leads to substantially more effective cleaning of the fibre flow or temporary yarn if it is operated in the manner of an open system, for example is disposed below the gap which is formed between two transport units and consequently uses in addition the natural gravity of any dirt particles and the like which are present. In particular, it is possible in an advantageous manner to undertake the suction with such a small low pressure that the transport of the fibre material in the transport units is consequently not impaired, as could be the case when using air supply devices which operate with blown air. In addition, the result advantageously is that the lighter particles are removed as before by suctioning out of the fibre flow, whilst the heavier particles, such as e.g. shell particles, are ejected at the same time through the open gap and then dropped for example as a result of gravity. The fibre flow which passes through the suction device is freed of disruptive components consequently surprisingly much more effectively than when using a closed system. Finally, it is also advantageous that the suction device can abut against an open gap, i.e. a closed system for guiding air is unnecessary, which facilitates access to the various components.
Further advantageous features of the invention are revealed in the sub-claims.
The invention is explained subsequently in more detail in embodiments in conjunction with the accompanying drawings. There are shown:
The slivers 7 are supplied to a drawing frame 9 via conveyor belts 8 or the like, which drawing frame is accessible for the operator from a working platform 10 disposed above the workplace floor 5. Such a drawing frame 9 is assigned to each of a large number of knitting systems, only one of which is shown in
A fibre web, not shown, which comes from the drawing frame 9 essentially comprises untwisted staple fibres which are disposed parallel to each other, is supplied, as is evident more precisely in
The transport device 15 which is configured as spinning device or each transport unit which comprises twisting member 16 and transport pipe 17 serves according to
Between two successive transport units, the compressed airflow required for producing turbulence is discharged externally via air removal openings which are formed by gaps 27 (
Circular knitting machines of the described type are known for example from documents PCT WO 2004/079 068 A2 and DE 10 2006 006 502 A1 which are herewith made the subject of the present disclosure in order to avoid repetitions by reference to them.
Analogously to
According to the invention and according to
The suction devices 31a, 31b or suction pipes can, as
Due to the bevel, an enlargement of the free opening and consequently of the space available for the suction at the outlet end of the respective transport pipe 17 is achieved, as a result of which the length of the gaps 27 measured in the transport direction v can be reduced in this case.
The angle at which the end face 33a is inclined relative to the axis of the transport pipe 17a can be different, as a comparison with a diagonal front or end face 33b at the outlet end of the transport pipe 17b shows in
Hence
Further possible embodiments of the configuration of the transport pipes 17 at the outlet ends thereof are evident in
A further advantageous embodiment can be obtained in that the diagonal end faces 33a are disposed directed towards the side and the axes of the suction devices 31 horizontally instead of vertically as in
Furthermore, it has proved to be expedient with respect to the desired cleaning effect to choose the lengths x1, x2 (
Moreover, the use of the dimensions 0<x≦2di has the advantage that, after breakage of the temporary yarn 22 or running empty of a transport unit 16, 17 for other reasons, no problems arise with starting to spin again and the forming yarn 22 is automatically threaded into the inlet opening of the respectively subsequent transport unit.
As in particular
This special feature resides in the fact that the transport pipes 17a to 17c, regarded per se, have in fact continuously constant internal diameters, these internal diameters however become gradually smaller from the drawing frame 9 in the direction of the knitting machine 1. In particular, the transport pipe 17a has the largest internal diameter, the transport pipe 17b a medium one and the transport pipe 17c the smallest one. Consequently, the advantage is achieved that the transport line formed from the transport pipes 17a, 17b and 17c has at the beginning a comparatively large internal diameter and at the end a comparatively small internal diameter. The large initial diameter assists undisturbed transfer of the fibre flow coming from the drawing frame 9, whilst the small end diameter assists undisturbed insertion of the fibre flow 4 into the knitting needles 3. In this case, the gap 27a, 27b between successive transport units 16, 17 is expediently dimensioned to be so large that, of the quantity of air which emerges from the preceding transport units which have larger internal diameters, only as much is transferred to the subsequent transport units as they are able to receive because of their smaller internal diameter.
It is particularly advantageous if the transition from a preceding first transport unit (e.g. 16a, 17a) in the transport direction v to a directly subsequent second transport unit (e.g. 16b, 17b) is chosen to be larger than the transition from this second transport unit (e.g. 16b, 17b) to a further subsequent third transport unit (e.g. 16c, 17c). In this case, the temporary yarn 22 forms a comparatively large balloon in the first transport pipe 17a, which assists good separation of the entrained foreign particles in the subsequent first gap 27a. As a result, the largest part of the impurities is removed already in the region of this gap 27a. Therefore subsequent transport pipes, in particular the last transport pipes 17c respectively in the transport direction v, obtain a correspondingly reduced internal diameter, as a result of which the balloon formation is smaller and a narrower guidance is achieved, which is advantageous for clean insertion of the fibre material into the knitting needles.
A further advantageous embodiment (
As
The cleaning effect is particularly good if the transport pipe 36a is disposed in the first end wall 42b sealed for example with the help of an O-ring 44 and therefore the suction effect of the suction pipe 41 becomes effective almost exclusively in the region between the edge of the outlet opening 43 and the transport pipe 36a.
In order that the suction chamber 42 can be produced simply and opened and cleaned when required, the second end wall 42b is configured expediently as a cover which is connected in a sealed and detachable manner to the suction chamber 42. A further O-ring 45 can serve expediently for sealing. At the same time, it is achieved with the help of the O-rings 44, 45 that the suction chamber 42 can be configured, apart from the suction pipe 41 and the region between the end wall 42b and the transport pipe 36a which opens into the gap 39, as a completely closed housing which is situated opposite the inlet end 38 of the subsequent transport unit 35b, 36b at a spacing.
Corresponding suction chambers 42 can be provided at the transitions between further, not shown transport units.
Moreover, the transport units evident in
The invention is not restricted to the described embodiments which can be modified in many ways. For example, the described angles evident in the drawing, at which the end faces are bevelled at the outlet ends of the transport units, should only be understood as examples which can be deviated from according to expediency. The same is true for the angles between successive transport units (e.g. 16b, 17b and 16c, 17c in
Claims
1. Device for transporting fibre material between a drawing frame (9) and a loop-forming machine (1) containing at least two transport units which are disposed in succession in a transport direction (v) and have respectively one inlet end (29, 37) and one outlet end (28, 38), said transport units being formed from respectively one twisting member (16a, 16b, 16c, 35a, 35b) and one transport pipe (17a, 17b, 17c, 36a, 36b) connected thereto, there being provided between an outlet end (28, 37) of a preceding transport unit and the inlet end (29, 38) of a subsequent transport unit an open gap (27a, 27b, 39) which is intended for forming an air removal opening, characterised in that, in the region of the gap (27a, 27b, 39), a suction device (31a, 31b, 40) which is open towards the latter is disposed.
2. Device according to claim 1, characterised in that the gap (27, 27b, 39) has a smallest length x measured in the transport direction (v) which fulfils the inequation 0<x≦2di, di being the internal diameter at the outlet end (28, 37) of the preceding transport unit.
3. Device according to claim 1, characterised in that the transport pipes (17a, 17b, 17c, 36a, 36b), observed in the transport direction (v), have increasingly smaller internal diameters.
4. Device according to claim 1, characterised in that the outlet end (28a) of at least one transport unit (16a, 17a) is provided with an outlet opening which extends diagonally relative to the axis thereof.
5. Device according to claim 1, characterised in that the transport pipes (17a, 17b, 17c, 36a, 36b) have axes which extend parallel to each other.
6. Device according to claim 5, characterised in that the axes of two successive transport pipes (17a, 17b, 17c) are disposed with a preselected offset (A1, A2) which extends transversely relative to the transport direction (v).
7. Device according to claim 6, characterised in that the offset (A1, A2) is at most equal to half the internal diameter of the respectively subsequent transport pipe.
8. Device according to claim 1, characterised in that the suction device contains a suction pipe (31a, 31b, 40).
9. Device according to claim 8, characterised in that the suction pipe (31a) has an axis (32a1, 32a2) which extends diagonally relative to the transport direction (v).
10. Device according to claim 4, characterised in that the suction pipe (31a, 31b) contains a bevelled outlet opening which is orientated towards the gap (27a, 27b).
11. Device according to claim 1, characterised in that the axes of successive transport pipes (17b, 17c) form an angle with each other.
12. Device according to claim 1, characterised in that the suction device (40) has a suction chamber (42) which is connected to a suction pipe (41), having a first end wall (42a) and a second end wall (42b) which is situated opposite said first end wall, the transport pipe (36a) of the preceding transport unit protruding through a passage of the first end wall (42a) and extending up to the second end wall (42b) which, in the region of the gap (39), has an outlet opening (43) which is situated opposite the inlet end (38) of the subsequent transport unit and has an inner cross-section which is larger than the outer cross-section of the transport pipe (36a) of the preceding transport unit at this position.
13. Device according to claim 12, characterised in that the transport pipe (36a) of the preceding transport unit is disposed sealed in the first end wall (42a).
14. Device according to claim 12, characterised in that the second end wall (42b) is configured as a cover which is connected in a sealed and detachable manner to the suction chamber (42).
15. Circular knitting machine, characterised in that it is provided with at least one device according to claim 1.
Type: Application
Filed: Aug 1, 2008
Publication Date: Feb 3, 2011
Inventors: Wolfgang Bauer (Kornwestheim), Axel Flad (Burladingen)
Application Number: 12/673,700
International Classification: D01H 5/66 (20060101); D04B 9/00 (20060101);