KNITTED FABRIC AND METHOD AND DEVICE FOR PRODUCING THE KNITTED FABRIC

Abstract

A method and device for producing knitted fabric include supplying roving to a stretching unit with stretching roller pairs and a spinning nozzle device and drawing the roving using the stretching roller pairs. Inlet and outlet roller pairs of the stretching unit are controllably driven, according to a pattern to be formed on the machine, so that the thread thickness of the drawn roving is varied by changing the relative speed between inlet and outlet roller pairs. The drawn roving is supplied to the spinning nozzle device and strengthened by applying compressed air, and the drawn, strengthened roving is supplied to the machine. The thread supply speed of the drawn, strengthened roving to the machine is set depending on the loop size to be knit by the machine by controlling rotation speed of at least one driven roller of the outlet roller pair. A knitted fabric is also provided.

Claims

1-15 (canceled)

16. A method for producing a knitted fabric having a pattern, the method comprising the following steps: supplying a sliver formed as a roving of unstrengthened fiber bundles to a roving drawing and strengthening unit including a stretching unit with at least two stretching roller pairs successively disposed in a thread transport direction and a spinning nozzle device disposed downstream of the stretching unit in the thread transport direction and drawing the roving using the at least two stretching roller pairs; controllably driving at least one inlet roller pair and one outlet roller pair of the stretching unit according to the pattern of the knitted fabric to be formed on a knitting machine causing a thread thickness of the drawn roving to be varied along its length by changing a relative speed between the inlet roller pair and the outlet roller pair; supplying the drawn roving exiting the stretching unit to the spinning nozzle device and strengthening the drawn roving by applying compressed air; then supplying the drawn, strengthened roving to the knitting machine directly or by using a transport or clamping device; and setting a thread supply speed of the drawn, strengthened roving to the knitting machine depending on a loop size to be knit by the knitting machine by controlling a rotation speed of at least one driven roller of the outlet roller pair of the stretching unit.

17. The method according to claim 16, which further comprises setting the roller speed based on: the bigger the loop size to be knit by the knitting machine, the smaller the relative speed between the inlet roller pair and the outlet roller pair and the bigger the rotation speed of the at least one driven roller of the outlet roller pair is set, and the smaller the loop size to be knit by the knitting machine, the bigger the relative speed between the inlet roller pair and the outlet roller pair and the smaller the rotation speed of the at least one driven roller of the outlet roller pair is set.

18. The method according to claim 16, which further comprises setting a relative speed between the inlet roller pair and the outlet roller pair to be inversely proportional to the loop size to be knit by the knitting machine and setting the rotation speed of the at least one driven roller of the outlet roller pair to be directly proportional to the loop size.

19. The method according to claim 16, which further comprises supplying the drawn, strengthened roving to the knitting machine with constant thread tension.

20. The method according to claim 16, which further comprises supplying at least one auxiliary thread to the stretching unit, and controlling an auxiliary thread supply speed to the stretching unit depending on at least one of the loop size of the knitted fabric to be formed on the knitting machine or stretch characteristics of the auxiliary thread.

21. The method according to claim 16, which further comprises forming a plurality of drawn, strengthened rovings on separate roving drawing and strengthening units, supplying the drawn, strengthened rovings to separate knitting systems of the knitting machine by using the roving drawing and strengthening units, and controlling and operating the roving drawing and strengthening units independently of each other.

22. The method according to claim 16, which further comprises combining a plurality of roving drawing and strengthening units into one module and jointly electronically controlling the roving drawing and strengthening units.

23. The method according to claim 21, which further comprises supplying each respective knitting system of the knitting machine with drawn, strengthened roving from at least two of the roving drawing and strengthening units.

24. The method according to claim 22, which further comprises supplying each respective knitting system of the knitting machine with drawn, strengthened roving from at least two of the roving drawing and strengthening units.

25. A device for producing a knitted fabric, the device comprising: at least one knitting machine including a sinking depth adjustment device; at least one roving drawing and strengthening unit disposed upstream of said at least one knitting machine in a thread transport direction, said at least one strengthening unit including at least one stretching unit with at least two stretching roller pairs being successively disposed in the thread transport direction and at least one spinning nozzle device disposed downstream of said at least one stretching unit in the thread transport direction, said at least two stretching roller pairs including an inlet roller pair and an outlet roller pair each having at least one respective driven roller; at least one drive coupled to said at least one driven roller of said inlet roller pair and to said at least one driven roller of said outlet roller pair; a pattern control for said at least one knitting machine, said pattern control being coupled to said at least one drive; and said pattern control and said at least one drive being coupled to said sinking depth adjustment device.

26. The device according to claim 25, which further comprises at least one thread tension measuring device for determining a thread tension of a drawn, strengthened roving exiting said at least one roving drawing and strengthening unit.

27. The device according to claim 25, which further comprises at least one auxiliary thread supply device being connected to said at least one stretching unit and being controllable by at least one of said pattern control for said at least one the knitting machine or in dependence on stretch characteristics of an auxiliary thread to be supplied to said at least one stretching unit.

28. The device according to claim 25, wherein: said at least one strengthening unit includes at least two separate strengthening units being independently controlled; and said at least one knitting machine includes knitting systems each being associated with said at least two separate roving drawing and strengthening units.

29. The device according to claim 25, wherein said at least one strengthening unit includes a plurality of strengthening units combined into one module and coupled for control.

30. A knitted fabric, comprising: a drawn, strengthened roving having a thread thickness varying along its length; said thread thickness of said drawn, strengthened roving being formed in dependence on a respective loop size of the knitted fabric; and said thread thickness increasing with increasing loop size and decreasing with decreasing loop size.

31. The knitted fabric according to claim 30, wherein the knitted fabric is a seamless, circularly-knitted, knitted fabric with varying diameter and constant opaqueness.

Description

[0064] Preferred embodiments of the present invention, their structure, function and advantages are explained in more detail by the following figures, wherein

[0065] FIG. 1 schematically shows a section of a drawn roving with varying thread thickness formable as an intermediate product in an embodiment of the method according to the invention in a side view;

[0066] FIG. 2 schematically shows a possible embodiment of a device according to the invention in a cut side view; and

[0067] FIG. 3 schematically shows another possible embodiment of a device according to the invention in a cut side view.

[0068] FIG. 1 schematically shows a section of a drawn roving 4b formable as an intermediate product of an embodiment of the method according to the invention in a side view, wherein the roving 4b comprises a length l in the shown example.

[0069] The roving section of the roving 4b shown in FIG. 1 comprises three areas 41, 41, 42, which are characterized by different thread thicknesses d, d. As depicted in FIG. 1, the roving 4b comprises a larger thread thickness d in the area 42 than in the areas 41, 41. Hereby, thread thickness d, d is adjusted to a pattern to be knit on the knitting machine, to which the roving 4b is supplied in a temporarily strengthened form as a drawn, strengthened roving. The thread thickness d, d and the length of the areas in which the roving 4b comprises a larger or smaller diameter, are thereby formed according to pattern. In contrast to the depiction in FIG. 1, the roving 4b can hereby also comprise a constant thread thickness d, d over a long distance. The thread thickness d, d can also vary at very short distances. The areas 41, 41, 42, in which the thread thickness d, d changes, can regularly recur or be formed irregularly according to pattern.

[0070] The drawn roving 4b consists of individual fibers 40, which encompass an auxiliary thread not visible here. Depending on the application, the auxiliary thread can be formed elastic or inelastic. A drawn roving, which does not comprise an auxiliary thread or more than one auxiliary thread, can also be formed.

[0071] FIG. 2 schematically shows an embodiment of an embodiment of a device 1 according to the invention in a cut side view, wherein the same reference signs as in FIG. 1 describe the same component and it is being referred to the above description in this regard.

[0072] The device 1 shown in FIG. 2 comprises a knitting machine 2 as well as a roving drawing and strengthening unit 10 coupled with the knitting machine 2.

[0073] The roving drawing and strengthening unit 10 comprises a stretching unit 5, a spinning nozzle device 6 provided downstream of the stretching unit 5 in a thread transport direction A and, in the shown embodiment, a clamping roller pair 7 subsequent to the to the spinning nozzle device 6 in the thread transport direction A.

[0074] In the embodiment shown in FIG. 2, the stretching unit 5 comprises three stretching roller pairs 51, 52, 53 successively arranged in the thread transport direction A, provided at distances 561, 562 to each other. In alternative embodiments, the device 1 can, however, also comprise only two stretching roller pairs 51, 53 or more than three stretching roller pairs 51, 52, 53. The stretching roller pairs 51, 52, 53 are in turn formed by two rollers 511, 512, 521, 522, 531, 532, respectively.

[0075] For producing a drawn, strengthened roving 4d, a sliver 4a in form a fiber bundle that has not been strengthened, is supplied to the first stretching roller pair 51 of the stretching unit 5 in thread transport direction A, the inlet roller pair. In the shown embodiment, the sliver 4a is provided by a roving supply unit 3, which comprises a flyer bobbin 31 and is led to the inlet roller pair 51.

[0076] In the stretching unit 5, the sliver 4a is stretched by means of the stretching roller pairs 51, 52, 53. For this, one roller 511, 521, 531 each of the respective stretching roller pair 51, 52, 53 is coupled with a drive 8, 8, 8, which drives the respective roller 511, 521, 531.

[0077] As shown in FIG. 2, the rollers 512, 522, 532 of the respective stretching roller pair 51, 52, 53 which are not driven, are pressed against the driven rollers 511, 521, 531 by means of a stretching unit pressure arm 54 using springs 541 in the exemplary shown device 1 according to the invention. Hereby, the rollers 512, 522, 532 are mounted in such a way that they can rotate in opposite direction to the rollers 511, 521, 531.

[0078] For producing the drawn roving 4b with thread thickness d, d adjusted to the respective loop size, the drives 8, 8, 8 are coupled with a pattern control 9, wherein the rotation speed x.sub.1 of the drive 8 of the roller 511 of the inlet roller pair 51 is particularly controlled relative to the rotation speed x.sub.3 of the outlet roller pair 53 depending on a pattern to be knit by the knitting machine 2 by changing the rotation speed x.sub.1 of the inlet roller pair 51 in the shown example, wherein the rotation speed x.sub.2 of the stretching roller pair 52 follows that of the stretching roller pair 51 with a predefined or selectable transmission ratio and the rotation speed x.sub.3 of the stretching roller pair 53 is kept constant.

[0079] In order to be able to influence the loop size to be knit as well, the pattern control 9 is furthermore coupled with a schematically depicted sinking depth adjustment device 91 of the knitting machine 2. Hereby, the process is advantageously controlled in such a way that the thread thickness d increases with increasing loop size and the thread thickness d also decreases with decreasing loops so that knitted fabrics such as leggings or tights can be produced, which comprise a nearly constant transparency or opaqueness even when being worn, whereby an unsightly show-through on spots which are potentially more stretched than others, can be prevented. In alternative variants, the process can, however, also be controlled in such a way that the thread thickness d, d decreases with increasing loop size and vice versa. Accordingly, particularly transparent areas in the knitted fabric can be formed.

[0080] The drawn roving 4b exiting the stretching unit 5 subsequently enters a spinning nozzle device 6. In the spinning nozzle device 6, a rotation of the drawn roving 4b by means of air jets takes place. The spinning nozzle device 6 thereby consists of two successively arranged spinning nozzles 61, 62 which are air twirling nozzles. The air currents generated by the two spinning nozzles 61, 62 comprise opposing rotation directions B, C so that a false twist is formed.

[0081] In the shown embodiment, a clamping roller pair 7 is provided subsequent to the spinning nozzle device 6 in the thread transport direction A, which comprises two clamping rollers 71, 72 being rotatable in opposite directions to each other. The drawn, strengthened roving 4c exiting the spinning nozzle device 6, is led through the clamping rollers 71, 72 pressed against each other, so that on the one hand a passage and on the other hand a clamping spot for the roving 4c is formed. Hereby, the clamping spot limits the fiber strengthening segment after the spinning nozzle device 6. The drawn, strengthened roving 4d exits the clamping roller pair, which is subsequently directly supplied to the knitting machine 2.

[0082] In the embodiment of the device 1 according to the invention depicted in FIG. 3, an inelastic auxiliary thread 22 is supplied to the roving 4b by means of an auxiliary thread supply device 220, which serves for increasing the strength of the drawn, strengthened roving 4d. The inelastic auxiliary thread 22 is thereby drawn off a spool 24 by an auxiliary thread clamping roller pair 23, in the shown embodiment supplied to the stretching unit 5 via a thread guiding tube 26 and integrated into the roving 4b. In the shown example, the inelastic auxiliary thread 22 is supplied to the last stretching roller pair of the stretching unit 5 in the thread transport direction A, that is the outlet roller pair 53, whereby the thread supply speed v.sub.4 of the auxiliary thread 22 thus only needs to be adjusted to the rotation speed x.sub.3 of the outlet roller pair 53.

[0083] The thread tension of the inelastic auxiliary thread 22 can be checked by means of a thread tension measuring device 43 provided between the auxiliary thread clamping roller pair 23 and the stretching unit 5. Especially with regard to the quality of the produced knitted fabric as well as the execution of the knitting process, it has proven to be advantageous if the device 1, 1 comprises the thread tension measuring device 43 for determining a thread tension of a roving 4d exiting the auxiliary thread clamping roller pair 23 so that the roving 4d can be supplied to the knitting machine 2 with constant thread tension.

[0084] In the embodiment of FIG. 3, an elastic auxiliary thread 25, for example an elastane thread, is furthermore supplied to the roving 4d by means of an additional auxiliary thread supply device 210. This elastic auxiliary thread 25 is led over a thread tension measuring device 42 by means of a circumferential drive with the possibility of setting the exact auxiliary thread tension and then supplied to the stretching roller pair 53. In the shown embodiment, the elastic auxiliary thread 25, along with the inelastic auxiliary thread 22, is supplied to the stretching unit 5 via the thread guiding tube 26 with a thread supply speed v.sub.5.

[0085] It is also advantageous if the auxiliary thread supply device 220, 210 is controlled by means of the pattern control and/or the stretching characteristics of the auxiliary thread 22, 25. Particularly if the auxiliary thread supply device 220, 210 is coupled with the pattern control, the auxiliary thread 23, 25 can be inserted according to pattern. Depending on the individual application, it can be chosen whether an elastic auxiliary thread 25 or an inelastic auxiliary thread 22 is used. Depending on the individual application, it can also be decided whether only one auxiliary thread 22 or 25 or, if necessary, several auxiliary threads 22, 25 are supplied to the roving 4b. Insofar as several auxiliary threads 22, 25 are inserted, they should, as shown in FIG. 3, be supplied to the stretching unit 5 by means of separate auxiliary thread supply devices 220, 210 with regard to potentially differing auxiliary thread tensions. In alternative embodiments, however, several auxiliary threads can also be supplied by means of a single auxiliary thread supply device.

[0086] Advantageously, knitted fabrics with loops of different sizes can easily be produced with the device 1, 1 according to the invention, whereby very transparent or opaque knitted fabrics can be provided with regard to the thread thickness d, d variable depending on the loop size. For changing the loop size, the thread supply speed from the roving drawing and strengthening unit to the knitting machine is varied which is realized by changing the rotation speed of the last stretching roller pair in thread transport direction A, that is the outlet roller pair 53.

[0087] With the present invention, it is also possible to produce different compression zones in one knit fabric tube by changing the loop size.

[0088] With the present invention, a knitted fabric with differing technical characteristics can furthermore be produced by changing the thread thickness or thread count. When changing the thread thickness, the fiber content in the finished thread is changed in the method according to the invention. During the process, the auxiliary thread fineness is set. Thus, conductive auxiliary threads can for example be sheathed with a different number of fibers which generates partially different characteristics in the respectively produced knitted fabric.

[0089] With the present invention it is possible to influence the rub resistance of a knitted fabric by adjusting the loop size and the thread count. The present invention can furthermore be used to influence the functional characteristics of a knitted fabric such as their moisture transport characteristics and/or heat retention properties. Furthermore, the thermal conductivity and/or the thermal isolating characteristics of knitted fabric can furthermore also or alternatively be influenced by means of the present invention.