DEVICE FOR FEEDING WEFT THREADS TO A GRIPPER HEAD OF A LOOM

Abstract

A device feeds first and second weft threads in a weft direction to a gripper head of a loom and includes a coupling unit that moves back and forth in a warp direction. A first and a second feed unit are adjacently arranged in the warp direction on the coupling unit and are configured to feed the first and the second weft threads to the gripper head. A positioning unit moves the coupling unit in the warp direction in a first position of the coupling unit and counter to the warp direction in a second position of the coupling unit. The first feed unit feeds the first weft thread to the gripper head when the coupling unit is in the first position and the second feed unit feeds the second weft thread to the gripper head when the coupling unit is in the second position.

Claims

1-16. (canceled)

17. A device for feeding a first and a second weft thread in a weft direction to a gripper head of a loom, the device comprising: a coupling unit configured to move back and forth in a warp direction when the device is installed laterally on the loom; a first and a second feed unit adjacently arranged in the warp direction on the coupling unit, the first and the second feed units configured to feed the first and the second weft threads, respectively, to the gripper head; a positioning unit configured to position the coupling unit in the warp direction in a first position of the coupling unit and counter to the warp direction in a second position of the coupling unit; and wherein the first feed unit feeds the first weft thread to the gripper head when the coupling unit is in the first position and the second feed unit feeds the second weft thread to the gripper head when the coupling unit is in the second position.

18. The device of claim 17, wherein the coupling unit is positionable such that the position of the first feed unit in the first position of the coupling unit and the position of the second feed unit in the second position of the coupling unit match in the warp direction during weft insertion.

19. The device of claim 17, wherein each of the first and second feed units comprises slides that are movable in the weft direction.

20. The device of claim 19, wherein each of the slides is individually motor-driven in and counter to the weft direction.

21. The device of claim 19, wherein each of the slides comprises an actuatable clamp configured to clamp and release the respective weft thread associated with each of the slides, and further comprising guide elements upstream of each of the clamps in the weft direction that guide the respective weft threads from above, below, and laterally.

22. The device of claim 20, wherein the common drive is controllable such that each of the slides are drivable to different away from or into the gripper head.

23. The device of claim 17, wherein each of the feed units comprise a strip-conveying unit having two revolving strip conveyors positionable in relation to each other, wherein the respective weft threads are conveyable in the weft direction between the strip conveyors.

24. The device of claim 17, further comprising a drive configured with the positioning unit.

25. The device of claim 17, wherein the coupling unit is configured on a fixed guide part having first guide structures, the coupling unit comprising guide elements that interact with the first guide structures to move the coupling in or counter to the warp direction.

26. The device of claim 25, wherein the first guide structures are configured to prevent one of the first or second feed units from moving in the weft direction as the coupling unit is positioned in and counter to the warp direction, and further comprising second guide structures on the guide part that enable the other of the second or first feed units to move in and counter to the weft direction.

27. The device of claim 26, wherein the first and second guide structures are formed by grooves or protrusions in or on the guide part.

28. The device of claim 17, further comprising a first weft thread storage unit having a first bobbin, the first weft thread guided from the first weft thread storage unit to the first feed unit, and a second weft thread storage unit having a second bobbin, the second weft thread guided from the second weft thread storage unit to the second feed unit.

29. The device of claim 28, wherein the first weft thread storage unit is arranged above the second weft thread storage unit such that the first weft thread and the second weft thread emerge from the first and second weft thread storage units, respectively, extending one above the other.

30. The device of claim 28, wherein: the first and the second weft thread storage units are aligned in the weft direction and the axes of the first and the second bobbins are aligned in the warp direction, or the first and the second weft thread storage units are aligned in the warp direction and the axes of the first and the second bobbins being aligned in the weft direction, and further comprising deflectors located to convey the first and the second weft threads in the weft direction.

31. A loom, comprising a gripper head that is movable through an open shed in and counter to a weft direction, and the device according to claim 17 for feeding the first and the second weft thread in the weft direction to the gripper head

32. A method for feeding a first and a second weft thread during production of woven fabric in a loom having a gripper head that draws the first and second weft threads through an open shed along a weft insertion line, the method comprising: locating the first and second weft threads next to one another in a plane in a warp direction at an edge of the woven fabric; moving the first and second weft threads in a first direction along the warp direction to position the first weft thread at the weft insertion line while deflecting the second weft thread clear of the weft insertion line; feeding the first weft thread along the weft insertion line to the gripper head that draws the first weft thread through the open shed; moving the first and second weft threads in a second opposite direction along the warp direction to position the second weft thread at the weft insertion line while deflecting the first weft thread clear of the weft insertion line; and feeding the second weft thread along the weft insertion line to the gripper head that draws the second weft thread through the open shed.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The invention is explained in greater detail in the present case with reference to figures, wherein:

[0038] FIGS. 1a-1f: show a top view of a schematically shown device according to the invention (without weft threads) with feed units which include slides, in various positions;

[0039] FIGS. 2a-2c: show a top view of the schematically shown device from FIGS. 1a-1f with inserted weft threads and weft thread storage units;

[0040] FIG. 2d: shows a side view of the schematically shown device according to FIGS. 2a-2c;

[0041] FIGS. 3a-3d: show an underside view of a schematically shown device according to the invention for illustrating the kinematics;

[0042] FIG. 4: shows a perspective top view of the front part of a slide;

[0043] FIGS. 5a-5f: show a schematic side view of various approach positions of a slide in relation to a gripper head; and

[0044] FIGS. 6a-6e show a schematic side view of another embodiment of a feed unit.

DETAILED DESCRIPTION

[0045] Reference will now be made to embodiments of the invention, one or more examples of which are shown in the drawings. Each embodiment is provided by way of explanation of the invention, and not as a limitation of the invention. For example features illustrated or described as part of one embodiment can be combined with another embodiment to yield still another embodiment. It is intended that the present invention include these and other modifications and variations to the embodiments described herein.

[0046] The top view from FIGS. 1a-1f highly schematically shows a device 1 according to the invention, which is designed to feed first and second weft threads S1, S2 (not shown in FIG. 1 for the sake of clarity; see FIGS. 2a-2d) to a gripper head 82 of a loom 80 which is shown highly schematically only in the cutout portion. The device 1 is arranged laterally with respect to the loom 80 and presents the first and the second weft threads S1, S2, which are to be inserted, to the gripper head 82.

[0047] The device 1 has a coupling unit 10, on which a first feed unit 30 and a second feed unit 50 are provided, the first feed unit 30 presenting the first weft thread S1 to the gripper head 82 and the second feed unit presenting the second weft thread S2 to the gripper head 82. The gripper head 82 pulls the weft thread, which has been presented thereto and subsequently clamped, through the open shed along the weft insertion line E by means of the gripper rod 84.

[0048] The two feed units 30, 50 are motion-coupled to each other via the coupling unit 10. The coupling unit 10 is movable by means of a drive 15, which is a pneumatic cylinder 16 having a pushing and pulling cylinder rod 17 (FIG. 3a) in the present case, along the woven-fabric edge in and counter to the warp direction KR in two defined positions in this case. Due to this movement of the coupling unit 10, the two feed units 30, 50 are also positioned in the warp direction KR.

[0049] In the present case, the first feed unit 30 and the second feed unit 50 include slides 31 and 51, respectively, which are movable in and counter to the weft direction SR. The first and the second slides 31, 51 are driven by means of a commonly used drive 42 which is a servomotor in the present case and is controlled by a control unit 5, the pneumatic cylinder 15 also being controlled by the control unit 5. The corresponding control lines are shown as dotted lines in FIG. 1.

[0050] In FIG. 1a, the coupling unit 10 is in a first position. In this first position of the coupling unit 10, the first feed unit 30 takes a position in which the first weft thread S1 lies in the weft insertion line E. According to FIG. 1b, the coupling unit 10 is still in the aforementioned first position, but the first feed unit 30 has advanced in the weft direction SR to the gripper head 82. In this position, the weft thread S1 is presented and transferred to the gripper head 82, whereupon the gripper head 82 travels through the open shed. After the first weft thread has been presented, the first feed unit 30 is moved counter to the weft direction SR back into its starting position by means of the drive 42.

[0051] According to FIG. 1c, the weft thread S1 can then be cut in the cutting plane SE by means of a cutting device 79 which is only schematically shown.

[0052] According to FIG. 1d, the coupling unit 10 is subsequently moved by means of the pneumatic cylinder 16 into its second position, in which the second weft thread S2, which has been placed in the second feed unit 50, is aligned with the weft insertion line E. According to FIG. 1e, the second feed unit is moved in the weft direction SR by means of the drive 42 to the gripper head 82, where the weft thread S2 is transferred. Thereafter, according to FIG. 1f, the second feed unit 50 moves back into its starting position and the second weft thread S2 is cut by means of the cutting device 79. Thereafter, the coupling unit 10 can be moved back into the position according to FIG. 1a.

[0053] FIGS. 2a-2d show the device 1 according to FIG. 1 in a schematic top view without a few features and showing other features. In the side view in FIG. 2d, it is apparent that the first weft thread S1 in an upper weft thread storage unit 70 is wound onto a bobbin 72. From there, the first weft thread S1 is guided via a deflecting roller 71 to the first feed unit 30. Arranged under the first, upper weft thread storage unit 70 is a second, lower weft thread storage unit 75 which stores a second bobbin 77 with the weft thread S2 wound thereon. From there, the second weft thread S2 is guided via a deflecting roller 76 to the second feed unit 50. The two weft thread storage units 70, 75 are aligned with each other in the top view (see FIGS. 2a-2c). The two weft threads S1, S2 initially extend essentially one above the other with very little clearance from each other, but then slightly apart from each other in the direction of the feed units 30, 50, as explained in the following with reference to FIGS. 2a-2c.

[0054] According to the top view in FIG. 2a, the first feed unit 30 with the slide 31 is located in a positionby suitably positioning the coupling unit 10 (not shown)in which its weft thread S1 can be inserted along the weft insertion line E by means of the gripper head 82. The second feed unit 50 is deflected slightly counter to the warp direction KR. In order to illustrate this, the central axis D2 of the second weft thread S2 is extended to the weft thread storage units 70, 75. It therefore becomes clear that there is a small angle between the weft insertion line E and the central axis D2 of the second weft thread S2. This is not critical, however, since the second weft thread S2 is not being inserted into the shed in this moment.

[0055] FIG. 2b shows once again how the first feed unit 30 brings the weft thread S1 to the gripper head 82. According to FIG. 2c, the coupling unit 10 (not shown) has been moved into the second position, in which the second weft thread S2 is aligned with the weft insertion line E. In this case, the first feed unit 30 is positioned outside the weft insertion line E, the central axis D1 of the weft thread S1 forming a small angle with the weft insertion line E.

[0056] FIGS. 3a-3d show a specific embodiment of the device 1 which is shown merely schematically in FIGS. 1 and 2. In contrast to FIGS. 1 and 2, FIGS. 3a-3d show an underside view of a device 1. The pneumatic cylinder 16 with its cylinder rod 17 is apparent. The cylinder rod 17 is connected to the coupling unit 10, such that the pneumatic cylinder 16 can move the coupling unit 10 back and forth in the warp direction KR.

[0057] The coupling unit 10 is essentially U-shaped in the underside view in the present case, protrusions 11 being provided on its two limb ends, the protrusions pointing downward (i.e., toward the observer in this case). These protrusions 11 are engaged with a first guide structure 21 which is formed as a guide groove and is provided in a guide part 20. The guide part 20 is installed in a fixed, i.e., stationary, manner, which is also the case for the pneumatic cylinder 16. The guide part 20 is a flat cuboid in the present case, which is used essentially for guiding the coupling unit 10 and the two feed units 30, 50. The aforementioned first guide structure 21 in the guide part 20 extends in the warp direction KR, such that the coupling element 10 with its protrusions 11 is forcibly guided via the first guide structure 21 in and counter to the warp direction KR when it is set into motion by the pneumatic cylinder 16.

[0058] The two slides 31, 51 of the first and the second feed units 30, 50, respectively, are arranged on the coupling element 10. Both slides 31, 51 can be moved in and counter to the weft direction SR. A drive mechanism is provided for this purpose, which is composed in this case of a drive 42 formed as a servomotor having a planetary transmission, a pivot lever 43 and a sliding block 45 which is stationarily arranged on the pivot lever but is rotatable by means of a rotational joint 44. Each of the two slides 31, 51 has on its underside (i.e., directed toward the observer) a recess 46 for the sliding block 45. The two recesses 46 are aligned with each other when the two slides 31, 51 are located at the same level in the weft direction SR (FIG. 3a, FIG. 3c).

[0059] A guide element 41 in the form of a protrusion is also provided on the underside of the first slide 31 and a guide element 56 which is also in the form of a protrusion is provided on the underside of the second slide 51. When the coupling unit 10 has been suitably positioned, specifically in its first or second position, these protrusions 41, 56 can slide, being forcibly guided, in and counter to the weft direction SR in a second guide structure 22 which is formed as a guide groove in the guide part 20 in the present case.

[0060] In FIG. 3a, the coupling unit 10 is shown in its first position, in which the first slide 31 is positioned such that it can be moved in the weft direction SR due to its protrusion 41. The protrusion 56 of the second slide 51 impacts the edge of the second guide structure 22, however, such that the second slide 51 is prevented from moving in the weft direction SR. In order to allow the second slide 51 to slide in the weft direction SR, the coupling unit 10 must be brought into its second position by means of the pneumatic cylinder 16 (see, for this purpose, the discussion associated with FIGS. 3c and 3d further below).

[0061] FIG. 3b shows howdriven by the drive 42 and the swivel mechanism including the sliding block 45the first slide 31 has been advanced in the weft direction SR, i.e., in the direction of the gripper head 82 (not shown) and has been forcibly guided by the protrusion 41 running in the second guide structure 22.

[0062] In FIG. 3c, the first and the second slides 31, 51 are at the same level again. The pneumatic cylinder 16 has now moved the coupling unit 10 in the warp direction KR into its second position, however. The sliding block 45 has slid into the recess 46 in the second slide 51. Thereafter, as shown in FIG. 3d, the second slide 51 can be moved by the drive 42 in the weft direction SR in order to present and transfer the second weft thread S2 to the gripper head 82.

[0063] In FIG. 4, the slide 31 of the feed unit 30 is shown in greater detail (the slide 51 of the feed unit 50 is preferably identical). In cross-section, the slide 31 has a metal plate 40 which is closed in a U-shaped manner. These two upwardly projecting lateral limbs of this metal plate 40 act as laterally guiding guide elements 39 for the weft thread (not shown), whereas the base of the metal plate 40 acts as a lower guide element 36. A clamp 32 is provided in the central area of the metal plate 40, which presses the weft thread downward by means of a pneumatically loaded push rod 33 (shown only in part). Situated upstream of the clamp 32 in the weft direction SR is an upper guide element 35 which is coupled to the clamp 32, has an open cross-section and presses the weft thread downward against the lower guide element 36 of the metal plate 40. The weft thread is therefore securely guided to the gripper head 82 laterally via the guide elements 39 and on its top side and its underside via the guide elements 35, 36.

[0064] Toward the rear, i.e., counter to the weft direction SR, the clamp 32 is also adjoined by an upper guide surface 34 for the weft thread, which is also oriented toward the U-shaped metal sheet, the weft thread passing between the metal sheet 40 and the upper guide surface 34.

[0065] In this embodiment, a first guide element 28, which is also U-shaped and which is optional, adjoins even farther toward the rear, in the direction of the weft thread storage unit 70. This is used for guiding the weft thread S1 to the first feed unit 30 in an ordered manner. The first guide element 28 is moved together with the first guide element 30 in and counter to the warp direction KR (by means of the coupling unit 10). It is also advantageous, although not necessary, when it is also moved back and forth in the weft direction SR by means of the drive 42.

[0066] In summary, in the described embodiments, the weft thread S1 or S2 to be inserted is selected from the two adjacently situated weft threads S1, S2 via a lateral displacement of the coupling unit 10 taking place in and counter to the warp direction KR. The displacement of the coupling unit 10 in and counter to the warp direction KR is initiated pneumatically in the present case, whereas a drive 42 in the form of a servomotor carries out the presentation of the selected weft thread S1 or S2 to the gripper head 82, the presentation taking place in the weft direction SR. Due to the selection of the aforementioned drive, the device according to the invention can be cost-effectively realized, since only one servodrive may be used for the feed movement and one pneumatic drive may be used for selecting the color. In WO 2011/015173 A1, however, two servodrives are necessary for the swivel kinematics. The color can be selected by switching between the two weft threads S1, S2 by means of the relatively cost-effective pneumatic cylinder 16.

[0067] In FIGS. 5a-5f, a transfer or a presentation of a first weft thread S1 (the second weft thread S2 could just as easily have been selected) to a gripper head 82 is shown in chronological sequence. FIGS. 5a-5f also demonstrate the aspect of the invention, which is also to be considered as standalone, of a device for feeding at least a first weft thread S1 to a loom having at least one gripper head 82, in which a coupling unit 10, at least two feed units 30, 50 and a positioning unit 15 are not absolutely necessarily provided. Such a device has at least a first feed unit 30, with which the at least one weft thread S1 is feedable in the weft direction SR to the gripper head 82, the first feed unit 30 having a first clamp 32, with which at least one portion of the at least one first weft thread S1 can be guided in a force-locked manner when this weft thread S1 is fed to the gripper head 82. This device is characterized in that the portion of the at least first weft thread S1 which is guided by the first clamp 32 is linearly conveyable by means of the first feed unit 30 in and counter to the weft direction SR with respect to the gripper head 82, this linear movement of the aforementioned portion of the at least first weft thread S1 taking place along the weft insertion line E.

[0068] According to FIG. 5a, the weft thread S1 is clamped by the schematically shown clamp 32 and guided in the direction of the gripper head 82 on the top side and the underside by means of guide elements 35, 36. The weft thread S1 is relatively flexible in this case and is to be securely clamped by the gripper head 82. A transfer strategy is selected for this purpose. According to FIG. 5b, the gripper head 82 opens, the gripper head 82 having an upper gripper part 85 with an upper clamping part 86 and a lower gripper part 87 with a lower clamping part 88. The slide 31 including the weft thread S1 is now inserted between the two clamp parts 86, 88 by moving the first feed unit 30 in the weft direction SR. As a result, the weft thread S1 actually arrives in the gripper head 82, i.e., when the slide 31 is moved in the weft direction SR, the free end of the weft thread S1 does not impact the front side of the lower clamp part, for example, and then can no longer be conveyed into the gripper head 82.

[0069] According to FIGS. 5c and 5d, the feed unit 30 is then moved back out of the gripper head 82, the free end of the weft thread S1 remaining between the upper clamp part 86 and the lower clamp part 88, however. In this way it is ensured that the flexible weft thread S1 is actually inserted behind the two clamp parts 86, 88. As shown in FIG. 5e, the gripper head 82 is now closed, the upper clamp part 86 and the lower clamp part 88 clamping the free end of the weft thread S1 in a force-locking manner. According to FIG. 5f, the clamp 32 now opens, thereby lifting the upper guide part 35. Thereafter, the gripper head 82 can be moved in the weft direction SR through the open shed, thereby carrying the weft thread S1 along.

[0070] If the weft thread S1 has a relatively great bending stiffness, the step in FIG. 5b, i.e., inserting the slide 31 between the two clamp parts 86, 88, can be dispensed with. In this case, a reliable transfer of the weft thread S1 can be reliably realized due to the greater bending stiffness of the weft thread also without over-inserting the slide 31, i.e., inserting the slide 31 in the weft direction beyond the clamping region between the two clamp parts 86, 88.

[0071] FIGS. 6a-6e show an alternative embodiment for the feed units 30, 50. Instead of a slide, the feed units 30, 50 in this embodiment each have a strip-conveying unit 60, which has two revolving strip conveyors 62 which are positionable in relation to each other and between which the weft thread S1 or S2 is conveyable in the weft direction SR in a force-locked manner. In the present case, each strip conveyor 62 has three rollers, of which at least one is actively driven.

[0072] FIG. 6a shows that the two strip conveyors 62 clamp, for example, a weft thread S1 between themselves. When the gripper head 82 is open, according to FIG. 6b, the weft thread S1 is advanced between the two clamp parts 86, 88, whereupon the gripper head 82 closes and the weft thread S1 is clamped (FIG. 6c). The two strip conveyors 62 are then moved apart from each other, so that the gripper head 82 can pull the weft thread S1 through the shed. According to FIG. 6d, the inserted weft thread S1 is cut, the strip conveyors 62 having been moved back into the clamping position. Thereafter, the free weft thread end can be moved by the strip conveyors 62 counter to the weft direction SR back into its starting position (see FIG. 6a).

[0073] In a brief summary, according to the invention, the weft threads S1, S2 to be fed to the gripper head 82 are situated next to each other ahead of the woven-fabric edge in the warp direction KR. They preferably come from weft thread storage units 70, 75 which are arranged one above the other. The weft thread S1, S2 to be inserted is selected by laterally moving the coupling unit 10 together with feed units 30, 50 which are in the form of slides (presentation slides) or a strip-conveying unit 60 in this case. The coupling unit 10 is moved laterally in or counter to the warp direction KR such that the weft thread S1 or S2 is preferably inserted without deflection during the weft insertion, while the weft thread S2 or S1 which is not to be inserted is laterally deflected in or counter to the warp direction KR by a small amount on its way from the weft thread storage unit 75 or 70, respectively, to the feed unit 50 or 30, respectively. This does not negatively affect this weft thread S2 or S1, since it is not moved in the weft direction SR in this phase.

[0074] The device according to the invention and the method according to the invention can also be readily expanded to include more than two weft threads.

[0075] In addition to the advantages which were initially described, the presented method makes it possible to precisely produce highly diverse weave patterns. For example, weft threads having various widths and/or materials and/or having different pretreatment can be used in order, for example, to obtain a suitable structure and/or pattern. Two (or more) identical weft threads can also be used, of course. One further advantage of using identical weft threads is that the machine does not need to be stopped when the supply of one weft thread has been initially inserted into the woven fabric and then a switch to the other weft thread is carried out without a pause. While this weft thread is being inserted, the weft thread that previously ran out can be replaced in the appropriate weft thread storage unit. In general, longer runtimes can be achieved with identical weft materials and by exchanging the weft thread storage units.

LIST OF REFERENCE SIGNS

[0076] 1 device [0077] 5 control unit [0078] 10 coupling unit [0079] 11 protrusions [0080] 15 positioning unit [0081] 16 pneumatic cylinder [0082] 17 cylinder rod [0083] 20 guide part [0084] 21 first guide structure [0085] 22 second guide structure [0086] 28 first and second guide elements [0087] 30 first feed unit [0088] 31 first slide [0089] 32 clamp [0090] 33 push rod [0091] 34 guide surface [0092] 35 upper guide elements [0093] 36 lower guide elements [0094] 39 laterally guiding guide elements [0095] 40 metal plate [0096] 41 guide element [0097] 42 drive (servomotor) [0098] 43 pivot lever [0099] 44 joint [0100] 45 sliding block [0101] 46 recess [0102] 50 second feed unit [0103] 51 second slide [0104] 56 guide element [0105] 60 strip-conveying unit [0106] 62 strip conveyor [0107] 70 first weft thread storage unit [0108] 71 deflecting roller [0109] 72 first bobbin [0110] 75 second weft thread storage unit [0111] 76 deflecting roller [0112] 77 second bobbin [0113] 79 cutting device [0114] 80 loom [0115] 82 gripper head [0116] 84 gripper rod [0117] 85 upper gripper part [0118] 86 upper clamp part [0119] 87 lower grip part [0120] 88 lower clamp part [0121] S1 first weft thread [0122] S2 second weft thread [0123] G woven fabric [0124] SR weft direction [0125] KR warp direction [0126] SE cutting plane [0127] E weft insertion line