CN109415849B

CN109415849B - Device for clamping weft threads

Info

Publication number: CN109415849B
Application number: CN201780041988.8A
Authority: CN
Inventors: E.弗克利特; W.胡雷尔贝克; R.库莱姆比尔
Original assignee: Picanol NV
Current assignee: Picanol NV
Priority date: 2016-07-04
Filing date: 2017-06-12
Publication date: 2021-09-03
Anticipated expiration: 2037-06-12
Also published as: EP3478882A1; BE1024401A1; EP3478882B1; WO2018007104A1; BE1024401B1; CN109415849A

Abstract

The invention relates to a device and a method for clamping a weft thread in a weaving machine, comprising at least one clamping unit (20, 21), a support element (16) and an opener element (40) having at least one finger (41, 42, 43), wherein the support element (16) and the opener element (40) are mounted in a displaceable manner relative to one another in a clamping direction (14), wherein each clamping element (22, 23, 24, 25) is mounted pivotably about a pivot axis (17, 18) perpendicular to the clamping direction (14) to the support element (16), and the opener element (40) is adapted to be arranged in an operating position, wherein, when the opener element (40) is arranged in the operating position, upon a relative displacement between the support element (16) and the opener element (40), the at least one finger (41, 42, 43) and the clamping element (22, 43), 23. 24, 25) to cause the clamping element (22, 23, 24, 25) to pivot about a pivot axis (17, 18) against the force of at least one force element (28, 29) to open an associated clamp (60, 61, 62, 63).

Description

Device for clamping weft threads

Technical Field

The present invention relates to a device and a method for clamping a weft thread in a weaving machine, more particularly in a rapier weaving machine.

Background

In a rapier loom (also called a gripper loom), a weft thread positioned in a gripper path is gripped by a gripper and inserted into a shed. The inserted weft thread is cut on the insertion side in order to allow the insertion of a subsequent weft thread. It is known to position a weft thread to be inserted in the gripper path by using a presentation element of a presentation device arranged on the weaving machine in the vicinity of the shed, as described for example in EP 0598264 a 1.

It is known to provide a clamping device arranged between the presenting device and the weft cutter. For example, US 5,492, 153, EP 0421349 a1 and WO 2013007551 a2 describe clamping devices with a plurality of clamping elements. One of these clamping elements is connected to the drive element, while the other clamping element is forced against the clamping element connected to the drive element by means of a spring element.

In US 5,492, 153, a device comprising a plurality of clamping elements is described, wherein two adjacent clamping elements define a clamp. The central clamping element is fixedly mounted to the rod and can be moved in the clamping direction by means of the rod. The other clamping elements are forced towards the central clamping element by means of springs. The device further comprises an opener element to move two adjacent gripping elements apart in order to allow the weft thread to enter between the two adjacent gripping elements. By means of the lever, two selected gripping elements can be moved in front of the opener element.

The device for gripping a weft thread according to WO 2013007551 a2 is adapted to cooperate with two weft threads. Several such means for gripping a weft thread may be provided, which allows weaving with more than two weft threads. For example, two such devices may be used, arranged mirror-symmetrically to each other. Nevertheless, the use of a plurality of such devices does not lead to a compact arrangement on the weaving machine.

Disclosure of Invention

The object of the present invention is to provide a device and a method for clamping a weft thread which allow a reliable clamping and release of the weft thread irrespective of its thickness.

This object is solved by a device, a weaving machine and a method for clamping a weft thread according to the invention.

According to a first aspect, there is provided an apparatus for gripping a plurality of weft threads, the apparatus comprising at least one gripping unit, a support element and an opener element with at least one finger, wherein the at least one gripping unit comprises: an abutment element fixedly attached to the support element; at least one clamping element movably mounted to the support element and arranged at one side of the abutment element, in particular two clamping elements are movably mounted to the support element at either side of the abutment element, respectively; and at least one force element, wherein each clamping element defines a clamp together with the abutment element, wherein the at least one force element forces each clamping element towards the abutment element, wherein the support element and the opener element are mounted displaceably relative to each other in a clamping direction, wherein each clamping element is pivotally mounted to the support element about a pivot axis perpendicular to the clamping direction, and wherein the opener element is adapted to be arranged in an operative position, wherein, when the opener element is arranged in the operative position, upon relative displacement between the support element and the opener element, the at least one finger interacts with one of the clamping elements to cause said clamping element to pivot about the pivot axis against the force of the at least one force element to open the associated clamp.

This allows each weft thread to be clamped in the associated clamp in a reliable manner and independently of the thickness of each weft thread.

In a preferred embodiment, the device comprises at least two clamping elements associated with one clamping unit or different clamping units. In one embodiment, only one clamping unit is provided, wherein the one clamping unit comprises two clamping elements movably mounted to the support element at either side of the abutment element, respectively. In other embodiments, two or more clamping units are provided, wherein each clamping unit comprises only one clamping element or two clamping elements, which are movably mounted to the support element at either side of the abutment element, respectively.

The abutment element is fixedly arranged at the support element. In one embodiment, the abutment element is manufactured integrally with the support element. In other embodiments, the abutment element is manufactured separately and attached to the support element in a fixed in position. The clamping element is pivotally mounted to the support element and the clamp is opened by pivoting the associated clamping element away from the abutment element against the force of the at least one associated force element. In a preferred embodiment, the clamping element is a double-sided lever, wherein the front end contacts the abutment element for forming the clamp, and wherein the rear end is forced by means of the force element for forcing the front end towards the abutment element. The force element is for example a spring which is mounted between the abutment element and the clamping element or between two clamping elements of one clamping unit.

Upon relative movement of the opener element and the support element in the clamping direction, a pivoting movement of one clamping element is caused by the interaction between the opener element (more particularly the fingers of the opener element) and said clamping element to open the respective clamp. In one embodiment, the opener element is movably mounted in the clamping direction to cause a pivoting movement of the clamping element. In a preferred embodiment, the opener element is held fixed in position in the clamping direction for allowing the clamping element to be moved away from the abutment element by movement of the support element. In one embodiment, the finger is fork-shaped having two teeth, wherein each tooth can interact with one gripping element of the gripping unit. In a preferred embodiment, a bar or spear shaped finger is provided which is arranged to interact with the clamping element.

In one embodiment, each clamping element is provided with an operating structure which is displaced from the pivot axis for interacting with at least one finger of the opener element upon relative displacement between the support element and the opener element. In one embodiment, the operating structure is arranged on a surface of the respective clamping element perpendicular to the clamping direction.

In a preferred embodiment, the operating structure is an operating pin projecting from a side surface of the respective clamping element, wherein in particular the operating pin is arranged between the pivot axis of the clamping element and the clamping position for the weft thread. When the operating pins are arranged between the clamping position and the pivot axis in a direction perpendicular to the clamping direction, one finger inserted between two operating pins of one clamping unit is sufficient for selectively operating two clamps associated with the abutment element, wherein one of the two clamping elements is forced to pivot about its pivot axis, depending on the direction of movement of the operating structure in the clamping direction relative to the opener element. In an embodiment, a single bar-shaped finger is provided as opener element, which is fixedly arranged in position in the clamping direction. In other embodiments, an opener element with fork-shaped fingers is provided, wherein each finger may be assigned to at least one clamping element of the clamping unit.

It will be clear to the skilled person that the opener element may be fixedly mounted in place when only one clamping unit is provided, wherein the clamping unit is moved back and forth in a clamping direction to open one of the two associated clamps. In a preferred embodiment, two or more clamping units are provided, wherein the opener element is mounted at a fixed height along the clamping direction in a manner displaceable along a feed direction perpendicular to the clamping direction between an operating position and a rest position, and wherein the support element is mounted in a manner displaceable along the clamping direction such that when the opener element is in the rest position by displacing the support element along the clamping direction, a selected clamping unit can be placed in front of the central finger of the opener element. In other words, the opener element can be moved into a rest position for displacing the support element together with the clamping element, wherein all clamps remain closed. After the selected gripping unit is placed in front of the fingers, the fingers are moved into the operating position and the displacement of the support element causes a pivoting movement of one of the gripping elements, as described above.

In a preferred embodiment, exactly two clamping units are provided, wherein the opener element comprises one central finger and two outer fingers, wherein the two outer fingers are displaced from the center finger in the feeding direction, wherein the opener element is movable in the feeding direction between a rest position, a first operating position and a second operating position, wherein the opener element, when arranged in the first operating position or the second operating position, interacts with the clamping element upon a relative displacement between the support element and the opener element in a clamping direction, such that the central finger and one of the two outer fingers interact with one of the gripping elements, to cause the clamping element to pivot about the pivot axis against the force of the at least one force element to open the associated clamp or for reducing the clamping force at the associated clamp. This allows opening the clamp when the corresponding clamping unit is not placed in front of the center finger. For example, when arranging a first clamp (provided at a first clamping unit located in front of the central finger) for receiving an inserted weft thread, after receiving the weft thread and closing the first clamp, the opener element may be moved into the second operating position and by displacing the support element in the clamping direction relative to the opener element, a second clamp (provided at a second clamping unit not arranged in front of the central finger) may be opened or the clamping force at the clamp may be reduced by means of one of the outer fingers.

In order to avoid any unnecessary movement between the opener element and the support element, in a preferred embodiment two outer fingers are arranged at either side of the central finger, respectively, in the clamping direction and are displaced from the central finger in the clamping direction, wherein the distance between the central finger and each outer finger is at least substantially equal to the distance between the abutment elements of the two clamping units. In other words, when the center finger is placed in front of one of the clamping units, one of the outer fingers is placed in front of the other clamping unit.

In a preferred embodiment, the opener element is formed such that the central finger does not interfere with the clamping element when a relative displacement between the support element and the opener element in the clamping direction occurs when the opener element is in the second operating position.

In a preferred embodiment, a first drive device comprising a first motor is provided for displacing the support element in the clamping direction, wherein in particular the first drive device comprises a first eccentric which is driven to pivot about a first drive axis perpendicular to the clamping direction. The eccentric allows a very precise positioning of the support element together with the clamping unit. Such a drive is not subject to wear and is insensitive to vibrations.

In one embodiment, the eccentric is in contact with the support element and directly drives the support element. In a preferred embodiment, the first drive means further comprises a slidably mounted first transfer element, wherein the first eccentric drives the first transfer element to move the first transfer element back and forth in the clamping direction upon rotation of the first eccentric. The design of the transfer element is suitably selected by the person skilled in the art. In a preferred embodiment, the first transfer element is a first frame, wherein the first eccentric is arranged inside the first frame. The stroke of the transfer element depends, among other things, on the size of the frame, the size of the eccentric, the relative position of the drive axis of the eccentric with respect to the center of the frame and/or the relative angular rotation of the drive axis. In one embodiment, the opposite surfaces of the eccentric and the frame are made of or coated with a wear resistant material. In a preferred embodiment, a wear protection ring is provided between the first eccentric and the first frame to limit wear.

In a preferred embodiment, second driving means comprising a second motor are provided for displacing the opener element in the feeding direction. In a preferred embodiment, the second drive means has an at least substantially similar design as the first drive means to reduce manufacturing costs.

In particular, in a preferred embodiment, the second driving means comprise a second eccentric driven to pivot about a second driving axis perpendicular to the feeding direction. In a preferred embodiment, the second drive means further comprise a slidably mounted second transfer element, wherein the second eccentric drives the second transfer element to move the second transfer element back and forth in the feed direction upon rotation of the second eccentric. In particular, the second transfer element may be a second frame, wherein the second eccentric is arranged inside the second frame, and wherein in particular a wear protection ring may be provided between the second eccentric and the second frame.

According to a second aspect, a weaving machine is provided with a device for clamping a weft thread. In a preferred embodiment, the device is arranged at an angle with respect to the insertion direction of the weaving machine, such that a weft thread entering the device extends at least substantially perpendicularly to the direction in which the weft thread enters the device.

According to a third aspect, a method for clamping a weft thread using a device comprising at least one clamping unit, a support element and an opener element with at least one finger is provided, wherein the clamping unit comprises: an abutment element fixedly mounted to the support element; at least one clamping element movably mounted to the support element and arranged at one side of the abutment element, in particular two clamping elements are movably mounted to the support element at either side of the abutment element, respectively; and at least one force element, wherein each clamping element defines with the abutment element a clamp, wherein the at least one force element forces the clamping element towards the abutment element, and wherein each clamping element is pivotally mounted to the support element about a pivot axis perpendicular to the clamping direction, the method comprising: when the opener element is arranged in the operating position, the support element is displaced relative to the opener element in a clamping direction, wherein the at least one finger interacts with one of the clamping elements to cause the clamping element to pivot about the pivot axis against the force of the at least one force element to open the associated clamp.

Drawings

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Like elements will be represented by like reference numerals throughout the drawings.

FIG. 1 is a top view of a device for gripping a weft thread, which is arranged on a rapier weaving machine;

fig. 2 is a perspective view of the device for clamping a weft thread of fig. 1;

fig. 3 is a side view seen in the direction of arrow S of fig. 1 in a first state;

FIG. 4 is a side view of FIG. 3 in a second state;

FIG. 5 is a side view of FIG. 3 in a third state;

FIG. 6 is a side view of FIG. 3 in a fourth state;

FIG. 7 is an enlarged perspective view of a portion of FIG. 3 in a fifth condition;

fig. 8 is a disassembled view of the device for clamping a weft thread of fig. 1; and

FIG. 9 is an exploded view of the support member and two clamping units of the device of FIG. 8;

fig. 10 is a perspective view of the device for clamping a weft thread of fig. 1.

Detailed Description

Fig. 1 shows a top view of a device 1 for gripping a weft thread, which is arranged on a rapier weaving machine (rapier weaving). The rapier weaving machine is only partially shown. The rapier weaving machine comprises: a presenting device 2 for presenting the

weft threads

7, 8, 9, 10; and a gripper 3 for gripping one or

more weft threads

7, 8, 9, 10 presented by the presenting means 2 and for inserting the presented weft thread into the shed. The rapier weaving machine further comprises a thread guide 4 and a cutting device 5. As can be seen in fig. 2, the device 1 for gripping a weft thread is arranged between the cutting device 5 and the thread guide 4. The cutting device 5 is attached to a support 6, which support 6 supports the device 1 for gripping a weft thread.

In fig. 1, four

weft threads

7, 8, 9, 10 are schematically shown. The device 1 is arranged for receiving a

weft thread

7, 8, 9, 10 at beat-up and holding a plurality of

weft threads

7, 8, 9, 10 after cutting the weft thread by means of the cutting apparatus 5. After insertion of one of these wefts, for example a second weft 8, the second weft 8 guided over the thread guiding device 4 extends from the presenting device 2 via the means 1 for gripping the weft and the cutting device 5 to the selvedge 11 and the woven cloth 12 with the wiring 13. As indicated in fig. 1, the selvage 11 is a side edge of the cloth 12 extending in the warp direction, while the wiring 13 is a beat-up edge of the cloth 12 extending in the weft direction. After the clamping of the weft thread 8 by means of the device 1, the clamped weft thread 8 is cut off by the cutting device 5 between the device 1 and the selvedge 11. During the subsequent insertion, one of the

weft threads

7, 8, 9, 10 presented by one of the presenting means 2 is received by the shuttle 3, the leading end of which is pulled out of the device 1 and the weft thread is inserted into the shed. After insertion, the inserted weft thread moves during beating-up to enter the associated gripper of the device 1.

As best seen in fig. 1, in the embodiment shown, the cutting device 5 forms a functional unit or module with the apparatus 1 for gripping a weft thread. The module can be positioned relative to the frame of the weaving machine, in particular in an adjustable position relative to the gripper path, the cabling and the selvedge, and is fixedly mounted in a suitable position to the frame of the weaving machine.

In fig. 1, the device 1 is arranged at an angle with respect to the insertion direction N, wherein the angle is adapted to the course of the weft thread 8 extending from the presentation device 2 to the selvedge 11, such that the gripping elements (not shown in detail in fig. 1) of the device 1 extend in a direction at least substantially perpendicular to the direction in which the weft thread enters the device 1. Such an arrangement facilitates capturing of the weft thread.

Fig. 2 shows a perspective view of an embodiment of the device 1 according to the invention and the arrangement of the device 1 with respect to the cutting apparatus 5 and the thread guide 4. Fig. 3 to 7 show side views of the device 1 of fig. 2 seen in the direction of the arrow S in fig. 1 in five different states of use. Fig. 8 is an exploded view of the device 1 of fig. 2. Fig. 9 is an exploded view of the support element 16 and the two clamping

units

20, 21 of the device 1 of fig. 2. Fig. 10 shows another perspective view of an embodiment of the device 1 according to the invention.

In the embodiment shown in fig. 2 to 10, the device 1 for clamping a weft thread comprises a support element 16 and two clamping

units

20, 21 which are arranged one above the other at the support element 16 in the clamping direction 14.

As best seen in fig. 7 and 9, each clamping

unit

20, 21 comprises two clamping

elements

22, 23, 24, 25, an

abutment element

26, 27 arranged between the two clamping

elements

22, 23, 24, 25, and a

force element

28, 29. In the embodiment shown, the

force elements

28, 29 are springs. The

abutment elements

26, 27 are fixedly arranged in position at the support element 16. In the embodiment shown, the

abutment elements

26, 27 are made in one piece with the support element 16. Each clamping

element

22, 23, 24, 25 defines, together with the associated

abutment element

26, 27, a

clamp

60, 61, 62, 63 which can clamp a weft thread in a clamping position between the clamping

element

22, 23, 24, 25 and the associated

abutment element

26, 27. In the exemplary embodiment shown, the clamping device 1 has four

clamps

60, 61, 62, 63, each for clamping one of the four weft threads 7, 8, 9, 10 (see fig. 1). For receiving a

weft thread

7, 8, 9, 10 in the clamp or for releasing a clamped

weft thread

7, 8, 9, 10, each clamping

element

22, 23, 24, 25 is pivotally mounted to the support element 16 about a

pivot axis

17, 18 perpendicular to the clamping direction 14, which

pivot axis

17, 18 is mounted to the support element 16. The clamping

elements

22, 23, 24, 25 each take the form of a double-sided lever, wherein at each clamping unit 20, 21 a

force element

28, 29 is arranged between the rear ends of the two clamping

elements

22, 23, 24, 25, and wherein the

force element

28, 29 forces the respective front ends of the two clamping

elements

22, 23, 24, 25 against the

abutment elements

26, 27. The clamping

elements

22, 23, 24, 25 are suitably formed for ensuring a good clamping in a specific area of the clamping

elements

22, 23, 24, 25. In the embodiment shown, the

abutment elements

26, 27 are provided with clamping surfaces having a T-shaped cross-section facing the clamping

elements

22, 23, 24, 25 having clamping surfaces with a corresponding U-shaped cross-section, as best seen in fig. 9. To open the clamping position, the associated clamping

element

22, 23, 24, 25 is pivoted about the

pivot axis

17, 18 against the force of the

force element

28, 29. In order to apply an operating force or movement to cause a pivoting movement of the clamping

elements

22, 23, 24, 25 about the pivot axes 17, 18, the clamping

elements

22, 23, 24, 25 are provided with

operating pins

44, 45, 46, 47 projecting from the side surfaces of the clamping

elements

22, 23, 24, 25. In the embodiment shown, each operating

44, 45, 46, 47 is arranged in the feed direction 15 between the

pivot axis

17, 18 and the clamping position of the associated clamping

element

22, 23, 24, 25. Thus, a force directed away from the

abutment elements

26, 27 applied to the operating pins 44, 45, 46, 47 will cause a pivoting movement of the clamping

elements

22, 23, 24, 25 to open the clamp.

The operation of the device is explained with reference to fig. 3 to 7. For operation, the device 1 comprises an opener element 40. The support element 16 together with the clamping

units

20, 21 is displaceable in the clamping direction 14 relative to the opener element 40 by means of the first drive means 30. In the embodiment shown, the clamping direction 14 is oriented substantially vertically. However, this orientation is not necessary for the operation of the device, and other orientations are contemplated. Furthermore, the opener element 40 is arranged at a fixed height in the clamping direction 14 between the rest position, the first operating position and the second operating position in such a way that it can be displaced in the feeding direction 15 perpendicular to the clamping direction 14. The movement of the opener element 40 is effected by means of the second drive means 50.

The pivoting movement of the clamping

elements

22, 23, 24, 25 for opening the

clamps

60, 61, 62, 63 is effected by means of the opener element 40. In the embodiment shown, the opener element 40 has a central finger 41 projecting in the feed direction 15, which in the first operating position can interact with an

operating pin

44, 45, 46, 47 projecting from a side surface of the clamping

element

22, 23, 24, 25.

In the state shown in fig. 3, the opener element 40 is moved to a rest position away from the support element 16. When the opener element 40 is in the rest position (as shown in fig. 3), the support element 16 can be moved back and forth in the clamping direction 14 by means of the first drive means 30, wherein all clamping positions remain firmly closed due to the force exerted by the

force elements

28, 29. To open the clamping position of the upper clamping unit 20, the support element 16 is moved such that the associated clamping unit 20 is placed in front of the central finger 41 of the opener element 40. Next, the opener element 40 is driven to move in the feeding direction 15 into the first operating position.

In the embodiment shown, in the first operating position the opener element 40 is moved towards the clamping unit 20 such that the central finger 41 enters between the two operating

pins

44, 45 of the two clamping

elements

22, 23 of the clamping unit 20 placed in front of the central finger 41, as shown in fig. 4. Then, the support member 16 is driven to move upward or downward in the clamping direction 14.

When the support element 16 is moved upwards (as shown in fig. 5), the central finger 41 interacts with the operating pin 45 of the lower clamping element 23 of the two clamping

elements

22, 23. The joint movement of the operating pin 45 together with the support element 16 in the clamping direction 14 is thus hindered by the central finger 41. The clamping element 23 is pivotally mounted to the support element 16 about a pivot axis 18, which pivot axis 18 is arranged at the support element 16 and moves together with the support element 16. The clamping element 23 is caused to perform a pivoting movement about the pivot axis 18 by a movement of the support element 16 relative to the central finger 41. Similarly, when the support element 16 is moved downwards from the state shown in fig. 4, the central finger 41 interacts with the operating pin 44 of the upper clamping element 22 of the two clamping

elements

22, 23, causing a pivoting movement of this clamping element 22 about a pivot axis 17, which pivot axis 17 is arranged at the support element 16 and moves together with the support element 16.

The central finger 41 is fixedly arranged in position in the clamping direction 14, wherein the position of the central finger 41 is adapted to the position and design of the thread guide 4, thereby allowing a good guidance of the inserted weft thread into the

clamps

60, 61, 62, 63 towards the clamping position. As shown in fig. 5, the support element 16 is preferably moved so as to open the clamp 61 such that the abutment element 26 and the clamping element 23 are at least substantially aligned with the

guide elements

64, 65, 66 of the wire guide 4. Thereby, the inserted weft thread is guided by the

guide elements

64, 65, 66 of the thread guiding device 4 to the associated clamp 61, which is arranged almost in alignment with the

guide elements

64, 65, 66. The guide element 66 is arranged in an angular position settable with respect to the thread guide 4 so as to set a separation (split) between the

guide elements

65 and 66 in the vicinity of the clamp.

In order to release the clamped weft thread for insertion, the respective clamp can be opened by means of the central finger 41 as described above. In the embodiment shown, the opener element 40 has two additional

outer fingers

42, 43 arranged at either side of the central finger 41, respectively. The

outer fingers

42, 43 are displaced from the central finger 41 in the clamping direction 14, wherein the distance between the

outer fingers

42, 43 and the central finger 41 is selected such that when one

clamping unit

20, 21 is arranged in front of the central finger 41, one of the

outer fingers

42, 43 can enter between the operating pins 44, 45, 46, 47 of the

other clamping unit

20, 21, which means that the outer finger 42 is intended to interact with the operating

44 or 45, the outer finger 43 is intended to interact with the operating

46 or 47, and the central finger 41 is intended to interact with the operating

44, 45, 46 or 47. In the state shown in fig. 4, the upper clamping unit 20 is positioned in front of the central finger 41 for receiving a weft thread in one of its grippers. From the rest position shown in fig. 3, the opener element 40 can be moved beyond the first operative position shown in fig. 4 and 5 towards the second operative position shown in fig. 6. To move the opener element 40 into the second operating position, the opener element 40 is moved beyond the first operating position towards the second operating position such that the distal end of the central finger 41 moves beyond the operating pins 44, 45 of the upper clamping unit 20 and the lower outer finger 43 moves between the operating pins 46, 47 of the lower clamping unit 21.

As shown in fig. 6, when the support member 16 is moved upward while the lower outer finger 43 is disposed between the operating pins 46, 47 of the lower clamping unit 21 (as shown in fig. 6), the lower clamping member 24 is pivoted about its pivot axis 18. Depending on the stroke of the support element 16, the clamp is fully opened, or only partially opened, so that the clamping force on the clamped weft thread (not shown) is reduced.

In the illustrated embodiment, the

outer fingers

42, 43 are displaced from the central finger 41 in the feeding direction 15 such that the

outer fingers

42, 43 are not in the movement path of the operating pins 44, 45, 46, 47 when the opener element 40 is in the first operating position (see fig. 4, 5) and the central finger 41 is positioned between the operating pins 44, 45, 46, 47. Furthermore, the central finger 41 is formed such that when the opener element 40 is in the second operating position (see fig. 6) and one of the

outer fingers

42, 43 is positioned between the operating pins 44, 45, 46, 47, interference or collision of the central finger 41 and the operating pins 44, 45, 46, 47 is avoided. For example, the central finger 41 is provided at its distal end with a projection 49 (see fig. 7) which interacts with the operating pins 44, 45, 46, 47 only in the first operating position.

Preferably, the support element 16 is only displaced over a small distance when the opener element 40 is in the second operative position (see fig. 6). To fully open the lower clamp 63, the opener element 40 is moved back into the rest position (see fig. 3) and the support element 16 is moved together with the clamping

units

20, 21 in the clamping direction 14 to bring the second clamping unit 21 in front of the central finger 41, so that upon moving the opener element 40 into the first operating position, the projection 49 of the central finger 41 enters between the operating pins 46, 47 of the lower clamping unit 21, as shown in fig. 7.

As best seen in fig. 8, a first drive device 30 is provided, which comprises a first eccentric 31 driven to pivot about a first drive axis 32 (the first drive axis 32 being perpendicular to the clamping direction 14) for displacing the support element 16 in the clamping direction. The first drive means 30 further comprise a first transfer element 33 in the form of a first frame, wherein the support element 16 is fixedly mounted to the first frame. In the embodiment shown, the support element 16 is fixedly mounted to the first frame by means of screws 19. Optionally, a pin 67 is provided for positioning the support element 16. The first eccentric 31 is arranged inside the first frame. The first frame drives the first eccentric 31 to move in the clamping direction 14 when the eccentric 31 rotates. In order to limit the wear between the first eccentric 31 and the first frame due to forces on the opposite parts, in the shown embodiment a wear protection ring 34 is provided at the periphery of the eccentric 31 between the eccentric 31 and the first frame.

The first drive means 30 further comprise a first motor 35 having a motor axis 36. The eccentric 31 is mounted to the motor axis 36 by means of a mounting element 37, which is formed integrally with the eccentric 31, and a fixing element 38, which is screwed to the mounting element 37 using screws 39.

The movement of the support element 16 is transferred to the

clamping elements

22, 23, 24, 25 and all clamping

elements

22, 23, 24, 25 are displaced together with the support element 16. In case the opener element 40 is in its rest position (as shown in fig. 3), during this movement the

clamping elements

22, 23, 24, 25 maintain their relative position with respect to the

abutment elements

26, 27 due to the force of the

force elements

28, 29 acting on the

clamping elements

22, 23, 24, 25, except for a negligible movement due to inertia and other effects. Furthermore, the movement of the support element 16 does not lead to a compression or deformation of the

force elements

28, 29. Thus, the clamping force remains at least substantially constant irrespective of the position of the support element 16 in the clamping direction 14.

The opener element 40 can be driven by means of the second drive means 50 to move in the feed direction 15 and into between the operating pins 44, 45, 46, 47 of the two clamping

elements

22, 23, 24, 25.

In the shown embodiment, the second drive means 50 adapted to displace the opener element 40 is similar in structure to the first drive means 30. The second drive means 50 comprise a second eccentric 51 driven to pivot about a second drive axis 52, which second drive axis 52 is perpendicular to the feed direction 15. The second drive means 50 further comprise a second transfer element 53 in the form of a second frame, wherein the opener element 40 is fixedly mounted to the second frame using screws 48 and pins 68. The second eccentric 51 is arranged inside the second frame, wherein, in the embodiment shown, a wear protection ring 54 is provided at the periphery of the second eccentric 51 between the second eccentric 51 and the second frame. The second eccentric 51 acts on the second frame to move the second frame in the feed direction 15 when the second eccentric 51 rotates. The second drive means 50 further comprises a second motor 55 having a second motor axis 56. The second eccentric 51 is mounted to the second motor axis 56 by means of a mounting element 57, which is formed integrally with the second eccentric 51, and a fixing element 58, which is screwed to the mounting element 57 using screws 59.

As indicated in fig. 2, 3 and 10, the first transfer element 33 is guided by a guide 70 provided in a main frame 69 of the apparatus 1, and the second transfer element 53 is guided by a guide 71 provided in the main frame 69 of the apparatus 1. In fig. 10, it has been shown that: the opener element 40 comprises a cavity 72 near the protrusion 49 which allows the operating pins 44, 45, 46, 47 to pass through the cavity 72, in particular when the opener element 40 is in the second operating position. The wire guide 4 is fixedly arranged in place and fixed to the main frame 69 using screws 73. The guide element 66 is part of a plate 78 which is fixed to the guide element 64 of the wire guide 4 using

screws

74 and 75. To set the angle between the guide element 66 and the guide element 64, the screw 75 may be moved along at least one

opening

76, 77 in the plate 78.

It will be clear to the person skilled in the art that in case the device 1 comprises only one

clamping unit

20, 21, a displacement of the opener element 40 in the feeding direction is not necessary and the opener element 40 may be fixedly arranged in position in the operating position as shown in fig. 4. It should also be clear that the feed direction does not necessarily need to be linear and perpendicular to the clamping direction, but may, according to an alternative, for example extend along an arc of a circle extending substantially perpendicular to the clamping direction.

The device and the method for clamping a weft thread according to the invention are not limited to the embodiments shown and described by way of example, but may also comprise variants and combinations of these embodiments which fall within the scope of the claims.

Claims

1. Device for clamping a plurality of weft threads (7, 8, 9, 10), comprising at least one clamping unit (20, 21), a support element (16) and an opener element (40) with at least one finger (41, 42, 43), wherein the at least one clamping unit (20, 21) comprises: an abutment element (26, 27) fixedly attached to the support element (16); at least one clamping element (22, 23, 24, 25) movably mounted to the support element (16) and arranged at one side of the abutment element (26, 27); and at least one force element (28, 29), wherein the at least one clamping element (22, 23, 24, 25) defines a clamp (60, 61, 62, 63) together with the abutment element (26, 27), wherein the at least one force element (28, 29) forces the at least one clamping element (22, 23, 24, 25) towards the abutment element (26, 27), and wherein the support element (16) and the opener element (40) are mounted in a displaceable manner relative to each other in a clamping direction (14), wherein the device comprises at least two clamping elements (22, 23, 24, 25), which at least two clamping elements (22, 23, 24, 25) are associated with one clamping unit (20, 21) or with different clamping units (20, 21), characterized in that: each clamping element (22, 23, 24, 25) is pivotally mounted to the support element (16) about a pivot axis (17, 18) perpendicular to the clamping direction (14); and the opener element (40) is adapted to be arranged in an operating position, wherein, when the opener element (40) is arranged in the operating position, upon relative displacement between the support element (16) and the opener element (40), the at least one finger (41, 42, 43) interacts with one of the clamping elements (22, 23, 24, 25) to cause the clamping element (22, 23, 24, 25) to pivot about the pivot axis (17, 18) against the force of the at least one force element (28, 29) to open the associated clamp (60, 61, 62, 63).

2. The apparatus of claim 1, wherein: each gripping element (22, 23, 24, 25) is provided with an operating structure (44, 45, 46, 47) which is displaced from the pivot axis (17, 18) for interacting with at least one finger (41, 42, 43) of the opener element (40) upon relative displacement between the support element (16) and the opener element (40).

3. The apparatus of claim 2, wherein: the operating structure (44, 45, 46, 47) is an operating pin projecting from a side surface of the respective clamping element (22, 23, 24, 25).

4. The apparatus of claim 3, wherein: the operating pin is arranged between the pivot axis (17, 18) of the respective clamping element (22, 23, 24, 25) and a clamping position for a weft thread (7, 8, 9, 10).

5. The apparatus of claim 1, 2 or 3, wherein: -providing two or more clamping units (20, 21), wherein the opener element (40) is mounted at a fixed height along the clamping direction (14) in a displaceable manner along a feeding direction (15) substantially perpendicular to the clamping direction (14) between the operating position and a rest position, and wherein the support element (16) is mounted in a displaceable manner along the clamping direction (14) such that the selected clamping unit (20, 21) can be placed in front of at least one finger (41, 42) of the opener element (40) when the opener element is in the rest position by displacing the support element (16) along the clamping direction (14).

6. The apparatus of claim 1, 2 or 3, wherein: providing two clamping units (20, 21), wherein the opener element (40) comprises one central finger (41) and two outer fingers (42, 43) displaced from the central finger (41) in a feeding direction (15) substantially perpendicular to the clamping direction (14), wherein the opener element (40) is movable in the feeding direction (15) between a rest position, a first operating position and a second operating position, wherein the opener element (40) interacts with one of the clamping elements (22, 23, 24, 25) upon a relative displacement between the support element (16) and the opener element (40) in the clamping direction (14) when arranged in the first or the second operating position such that the central finger (41) or the two outer fingers (42, 42), 43) Interacts with one of the clamping elements (22, 23, 24, 25) to cause the clamping element (22, 23, 24, 25) to pivot about the pivot axis (17, 18) against the force of the at least one force element (28, 29) in order to open the associated clamp (60, 61, 62, 63) or in order to reduce the clamping force at the associated clamp (60, 61, 62, 63).

7. The apparatus of claim 6, wherein: the outer fingers (42, 43) are arranged at either side of the central finger (41) in the clamping direction (14) and are displaced from the central finger (41) in the clamping direction (14), wherein the distance between the central finger (41) and each outer finger (42, 43) is at least substantially equal to the distance between the abutment elements (26, 27) of the two clamping units (20, 21).

8. The apparatus of claim 6, wherein: the central finger (41) is formed such that the central finger (41) does not interfere with the gripping elements (22, 23, 24, 25) when a relative displacement between the support element (16) and the opener element (40) in the gripping direction (14) occurs when the opener element (40) is in the second operating position.

9. The apparatus of claim 1, 2 or 3, wherein: a first drive device (30) comprising a first motor (35) is provided for displacing the support element (16) in the clamping direction (14).

10. The apparatus of claim 9, wherein: the first drive device (30) comprises a first eccentric (31) driven to pivot about a first drive axis (32) perpendicular to the clamping direction (14).

11. The apparatus of claim 10, wherein: the first drive arrangement (30) further comprises a slidably mounted first transfer element (33), wherein the first eccentric (31) drives the first transfer element (33) to move the first transfer element (33) back and forth in the clamping direction (14) upon rotation of the first eccentric (31).

12. The apparatus of claim 11, wherein: the first transfer element (33) is a first frame, wherein the first eccentric (31) is arranged inside the first frame.

13. The apparatus of claim 12, wherein: a wear protection ring (34) is disposed between the first eccentric (31) and the first frame.

14. The apparatus of claim 1, 2 or 3, wherein: -providing second driving means (50) comprising a second motor (55) for displacing the opener element (40) in a feeding direction (15) substantially perpendicular to the clamping direction (14).

15. The apparatus of claim 14, wherein: the second drive means (50) comprise a second eccentric (51) driven to pivot about a second drive axis (52) substantially perpendicular to the feed direction (15).

16. The apparatus of claim 15, wherein: the second drive arrangement (50) further comprises a slidably mounted second transfer element (53), wherein the second eccentric (51) drives the second transfer element (53) to move the second transfer element (53) back and forth in the feeding direction (15) upon rotation of the second eccentric (51).

17. The apparatus of claim 16, wherein: the second transfer element (53) is a second frame, wherein the second eccentric (51) is arranged inside the second frame.

18. The apparatus of claim 17, wherein: a wear protection ring (54) is disposed between the second eccentric (51) and the second frame.

19. The apparatus of claim 9, wherein: -providing second driving means (50) comprising a second motor (55) for displacing the opener element (40) in a feeding direction (15) substantially perpendicular to the clamping direction (14).

20. The apparatus of claim 19, wherein: the second drive means (50) comprise a second eccentric (51) driven to pivot about a second drive axis (52) substantially perpendicular to the feed direction (15).

21. A weaving machine comprising a device (1) according to any one of claims 1 to 20.

22. Method for clamping a weft thread using a device (1) comprising at least one clamping unit (20, 21), a support element (16) and an opener element (40) with at least one finger (41, 42, 43), wherein the at least one clamping unit (20, 21) comprises: an abutment element (26, 27) fixedly mounted to the support element (16); at least one clamping element (22, 23, 24, 25) movably mounted to the support element (16) and arranged at one side of the abutment element (26, 27); and at least one force element (28, 29), wherein the at least one clamping element (22, 23, 24, 25) defines a clamp (60, 61, 62, 63) together with the abutment element (26, 27), wherein the force element (28, 29) forces the clamping element (22, 23, 24, 25) towards the abutment element (26, 27), wherein the device comprises at least two clamping elements (22, 23, 24, 25), which at least two clamping elements (22, 23, 24, 25) are associated with one clamping unit (20, 21) or with different clamping units (20, 21), and wherein each clamping element (22, 23, 24, 25) is pivotally mounted to the support element (16) about a pivot axis (17, 18) perpendicular to a clamping direction (14), the method comprising: displacing the support element (16) relative to the opener element (40) in a clamping direction (14) when the opener element (40) is arranged in an operating position, wherein the at least one finger (41, 42, 43) interacts with one of the clamping elements (22, 23, 24, 25) to cause the clamping element (22, 23, 24, 25) to pivot about the pivot axis (17, 18) against the force of the at least one force element (28, 29) to open the associated clamp (60, 61, 62, 63).