A gripper

Abstract

 A gripper (10) for an Axminster gripper loom comprises a gripper body (12) and a gripper jaw (14). The gripper body (12) and the gripper jaw (14) are formed to define mutually engageable connectors (24,40) to pivotally connect the gripper jaw (14) to the gripper body (12).

Description

[0001] The present invention relates to a gripper for an Axminster gripper loom. The invention also relates to an Axminster gripper loom incorporating the gripper, a method of picking-up a tail of yarn in an Axminster gripper loom and a method of weaving a carpet.

[0002] An Axminster gripper loom includes a row of grippers each of which collects a tuft of yarn from a yarn supply and transfers the tuft to a weaving position of the loom for weaving into a carpet. Typically for each pick of the loom, each gripper undergoes a cycle of motion, which involves the gripper moving to the yarn supply, then to the weaving position, and then returning to the yarn supply.

[0003] When at the yarn supply, the gripper undergoes a closing operation in order to grip a tuft of yarn. The gripper remains in its closed position as it moves to the weaving position and then undergoes an opening operation to release the tuft after is has been caught in the carpet weave.

[0004] In an Axminster loom, the grippers automatically move through the cycle of motion and opening and closing operations normally under the direct motive drive from the main drive shaft of the loom.

[0005] Each gripper includes a gripper body and a gripper jaw pivotally connected to the gripper body by means of pivot. The pivot is commonly provided in the form of a rivet pin, which permits pivotal movement of the gripper jaw relative to the gripper body to open and close the gripper jaw.

[0006] In use the rivet pin can become loose, thereby allowing the gripper jaw to twist relative to the gripper body and/or fall apart. This leads to failure of the gripper.

[0007] It is an object of a first aspect of the invention to provide a gripper that does not require a rivet pin to pivotal connect the gripper jaw to the gripper body and thereby eliminate gripper failure otherwise caused by loosening of the rivet pin.

[0008] It is another object of the first aspect of the invention to provide a gripper formed from two components only.

[0009] According to a first aspect of the invention there is provided a gripper for an Axminster gripper loom comprising a gripper body and a gripper jaw, the gripper body and gripper jaw being formed to define mutually engageable connectors to pivotally connect the gripper jaw to the gripper body.

[0010] A plurality of such grippers may be used in an Axminster gripper loom.

[0011] It is an object of a further aspect of the invention to provide a gripper incorporating a spring-type element to allow different thicknesses of yarn to be gripped.

[0012] According to a second aspect of the invention there is provided a gripper for an Axminster gripper loom comprising a gripper body and a gripper jaw, the gripper jaw being pivotally connected to the gripper body and being formed to define a resilient lever to increase the gripping force of the gripper when actuated.

[0013] A plurality of such grippers may be used in an Axminster gripper loom.

[0014] According to a third aspect of the invention there is provided a method of picking up a tail of yarn and withdrawing a predetermined length of the yarn from a yarn carrier in an Axminster gripper loom comprising the steps of:

(i) moving a gripper having a gripper body and a gripper jaw to position gripping portions of the gripper body and the gripper jaw on opposite sides of a tail of yarn held in a yarn carrier;

(ii) driving the gripper jaw about a pivotal connection defined by mutually engageable connectors formed on the gripper body and the gripper jaw so as to move the gripping portions towards one another and thereby close the gripper about the tail of yarn; and

(iii) moving the gripper to withdraw a predetermined length of yarn from the yarn carrier.

[0015] According to a fourth aspect of the invention there is provided a method of picking up a tail of yarn and withdrawing a predetermined length of the yarn from a yarn carrier in an Axminster gripper loom comprising the steps of:

(i) moving a gripper having a gripper body and a gripper jaw to position gripping portions of the gripper body and the gripper jaw on opposite sides of a tail of yarn held in a yarn carrier;

(ii) driving the gripper jaw about a pivotal connection between the gripper body and the gripper jaw so as to move the gripping portions towards one another and thereby close the gripper about the tail of yarn, the gripper jaw being fonned to define a resilient lever to increase the gripping force of the gripper when actuated; and

(iii) moving the gripper to withdraw a predetermined length of yarn from the yarn carrier.

[0016] Either of these methods of picking up a tail of yarn and withdrawing a predetermined length of the yarn from a yarn carrier may be used in a method of weaving a carpet comprising the steps of:

(i) holding pluralities of yarns in a plurality of yarn carriers for selective presentation to a plurality of grippers;

(ii) selectively moving each of the yarn carriers to present a chosen yarn to a respective one of the grippers;

(iii) operating each gripper to pick up the tail of the chosen yarn and withdraw a predetermined length of the chosen yarn from the respective yarn carrier;

(iv) cutting each of the chosen yarns such that each gripper holds a tuft of yarn;

(v) operating each gripper to transfer the tufts of yarn to weaving positions in a carpet; and

(vi) securing each tuft of yarn in position within the carpet by means of a weaving process.

[0017] Embodiments of the invention will be described, by way of non-limiting examples, with reference to the accompanying drawings in which:

Figure 1 shows a gripper according to an embodiment of the invention in its open position;

Figure 2 shows the gripper of Figure 1 in its closed position;

Figure 3 shows a gripper body of the gripper of Figure 1; and

Figure 4 shows a gripper jaw of the gripper of Figure 1.

[0018] A gripper 10 according to an embodiment of the invention is shown in Figure 1.

[0019] The gripper 10 includes a gripper body 12 and a gripper jaw 14 pivotally connected to the gripper body 12 by means of a pivot 16 for movement between an open position (Figure 1) and a closed position (Figure 2) to enable the gripper 10 to grip a yarn 54.

[0020] The gripper body 12 (Figure 3) is a generally planar member formed to define a fixing portion 18 to mount the gripper 10 in an Axminster loom (not shown). At its other end, the gripper body 12 defines a gripping portion 20 and, between the two ends, a web portion 22 is provided on which a stud 24 is preferably formed.

[0021] Two staggered recesses 26,28 are preferably formed on the opposite faces 30,32 of the gripper body 12 between the web portion 22 and the gripping portion 20.

[0022] The gripper jaw 14 (Figure 4) is also a generally planar member formed to define a connection portion 34 to engage a mechanical drive means (not shown), which, in use, controls the opening operation of the gripper 10. At its other end, the gripper jaw 14 defines a gripping portion 36 and, between the two ends, a web portion 38 is provided in which an aperture 40 is preferably formed.

[0023] The gripper jaw 14 is also preferably shaped to define two staggered tongues 42,44 protruding laterally from opposite faces 46,48 of the gripper jaw 14 between the web portion 38 and the gripping portion 36.

[0024] The gripper body 12 and the gripper jaw 14 are preferably formed from a hardened and tempered spring steel.

[0025] The stud 24 is preferably formed by removing material from the gripper body 12 to define the web portion 22 having a stud 24 protruding therefrom.

[0026] The web portions 22,38 on the gripper body 12 and the gripper jaw 14 are preferably located such that on assembly of the gripper 10, the stud 24 formed on the web portion 22 of the gripper body 12 is aligned with the aperture 40 formed in the web portion 38 of the gripper jaw 14.

[0027] Similarly, the tongues 42,44 protruding from the gripper jaw 14 are also preferably located such that on assembly of the gripper 10. the tongues are aligned with the recesses 26,28 formed in the gripper body 12.

[0028] During assembly of the gripper 10, the gripper jaw 14 is preferably positioned relative to the gripper body 12 such that the tongues 42,44 are aligned with open ends of the recesses 26,28, and the stud 24 on the gripper body 12 is aligned with the aperture 40 in the gripper jaw 14.

[0029] The relative shapes of the gripper body 12 and the gripper jaw 14 are preferably chosen such the connection portion 34 of the gripper jaw 14 must overlay the fixing portion 18 of the gripper body 12 in order to align the tongues 42,44, recesses 26,28, stud 24 and aperture 40.

[0030] Once the tongues 42,44, recesses 26,28, stud 24 and aperture 40 are aligned, the gripper jaw 14 is rotated relative to the gripper body 12 such that each of the tongues 42,44 slide into the respective recesses. This rotation moves the connection portion 34 of the gripper jaw 14 such that it no longer overlies the fixing portion 18 of the gripper body 12 and the stud 24 on the gripper body 12 is received in the aperture 40 formed in the gripper jaw 14. The gripper jaw 14 cannot then be disconnected from the gripper body 12 without twisting the connection portion 34 of the gripper jaw 14 to cause it to overlie the fixing portion 18 of the gripper body 12.

[0031] During opening and closing operation of the gripper 10, the tongues 42,44 slide in and out of the respective recesses 26,28. The lengths of the tongues 42,44 and the respective recesses 26,28 are preferably chosen such that the ends of the tongues 42,44 are retained within the respective recesses 26,28 when the gripper 10 is in its open position.

[0032] Preferably a projection 50 formed on the fixing portion 18 of the gripper body 12 limits pivotal movement of the connection portion 34 of the gripper jaw 14 relative to the gripper body 12 such that the ends of the tongues 42,44 are retained within the respective recesses 26,28 when the gripper 10 is in its open position.

[0033] The gripper jaw 14 is preferably formed to define a relatively narrow leg portion 52 between the web 34 and the connection portion 34. On movement of the connecting portion 34 to close the gripper 10 and grip a yarn 54 between the gripping portions 20,36 of the gripper body 12 and the gripper jaw 14, the leg portion 52 is preferably brought into contact with the projection 50 formed on the gripper body 12. The narrowness of the leg portion 52 allows the leg portion 52 to flex about the projection 50 such that the connection portion 34 may be moved further towards the gripper body 12 to ensure that the gripping portions 20,36 are closed tightly independent of the thickness of the yarn 54 gripped between the gripping portions 20,36. The material from which the gripper jaw 14 is formed is preferably resilient such that the leg portion 52 thereby forms a resilient lever to increase the gripping force of the gripper 10.

[0034] While the embodiment described with reference to Figures 1-4 include the provision of stud 24 and recesses 26,28 on the gripper body 12 and the provision of recess 40 and tongues 42,44 on the gripper jaw 14, it is envisaged in other embodiments that the stud 24 may be formed on the gripper jaw 14 and the recess 40 may be formed in the gripper body 12. It is also envisaged in other embodiments that the recesses 26.28 may be formed in the gripper jaw 14 and that the tongues 42,44 may be formed on the gripper body 12.

[0035] When the gripper 10 shown in Figure 1 is used in an Axminster gripper loom, a plurality of grippers 10 are ananged to pick-up the tails of yarns 54 and withdraw predetermined lengths of the yarn 54 from yarn carriers in the loom.

[0036] Each gripper 10 having a gripper body 12 and a gripper jaw 14 is moved to position the gripping portions 20,36 of the gripper body 12 and the gripper jaw 14 on opposite sides of a tail of yarn 54 held in a respective yarn carrier.

[0037] The gripper jaw 14 of each gripper 10 is driven about a pivotal connection defined by mutually engageable connectors 24,40 formed on the gripper body 12 and the gripper jaw 14 so as to move the gripping portions 20,36 towards one another and thereby close the gripper 10 about the respective tail of yarn Y_T.

[0038] Each gripper 10 is then moved to withdraw a predetermined length of yarn from the respective yarn carrier.

[0039] It is envisaged that in other embodiments, grippers 10 according to another embodiment of the invention may be arranged in an Axminster gripper loom to pick-up the tails of yarns 54 and withdraw predetermined lengths of the yarn 54 from yarn carriers in the loom.

[0040] In such embodiments, each gripper 10 having a gripper body 12 and a gripper jaw 14 is moved to position the gripping portions 20,36 of the gripper body 12 and the gripper jaw 14 on opposite sides of a tail of yarn 54 held in a respective yarn carrier.

[0041] The gripper jaw 14 of each gripper 10, being formed to define a resilient lever to increase the gripping force of the gripper 10 when actuated, is driven about a pivotal connection between the gripper body 12 and the gripper jaw 14 so as to move the gripping portions 20.36 towards one another and thereby close the gripper 10 about the respective tail of yarn Y_T, the gripper jaw 14.

[0042] Each gripper 10 is then moved to withdraw a predetermined length of yarn from the respective yarn carrier.

[0043] During operation of such looms to weave a carpet, a plurality of grippers are used to pick-up tails of yarn and withdraw predetermined lengths of the yarn from yarn carriers.

[0044] Pluralities of yarn 54 are held in a plurality of yarn carriers for selective presentation to the grippers 10, and each of the yarn carriers is moved selectively to present a chosen yarn to a respective one of the grippers 10.

[0045] Each gripper 10 is then operated to pick-up the tail of the respective chosen yarn 54 and withdraw a predetermine length of the chosen yarn 54 from the respective yarn carrier.

[0046] The chosen yarns 54 are then cut such that each gripper 10 holds a tuft of yarn 54 each gripper 10 then being operated to transfer the tufts of yarn 54 to weaving positions in the carpet where each tuft of yarn 54 is secured in position in the carpet by a weaving process.

Claims

1. A gripper for an Axminster gripper loom comprising a gripper body and a gripper jaw, the gripper body and the gripper jaw being formed to define mutually engageable connectors to pivotally connect the gripper jaw to the gripper body.

2. A gripper according to Claim 1 wherein each of the gripper body and the gripper jaw is a generally planar member having two ends and one of the gripper body and the gripper jaw is formed to define a stud between its two ends and the other of the gripper body and the gripper jaw is formed to define an aperture between its two ends.

3. A gripper according to Claim 1 or Claim 2 wherein the gripper body and the gripper jaw are formed to define mutually engageable retention members to resist separation of the mutually engageable connectors when the gripper jaw and the gripper body are pivotally connected.

4. A gripper according to Claim 3 wherein one of the gripper body and the gripper jaw is formed to define a pair of staggered tongues protruding laterally from opposite faces thereof and the other of the gripper body and the gripper jaw is formed to define a pair of staggered recesses formed in opposite faces thereof, the staggered tongues and staggered recesses being positioned such that the staggered recesses receive the staggered tongues for sliding movement therein when the gripper jaw and gripper body are pivotally connected.

5. A gripper for an Axminster gripper loom according to any one of the preceding claims wherein the gripper jaw is formed to define a resilient lever to increase the gripping force of the gripper when actuated.

6. A gripper for an Axminster gripper loom comprising a gripper body and a gripper jaw, the gripper jaw being pivotally connected to the gripper body and being formed to define a resilient lever to increase the gripping force of the gripper when actuated.

7. An Axminster gripper loom including a plurality of grippers according to any one of the preceding claims.

8. A method of picking up a tail of yarn and withdrawing a predetermined length of the yarn from a yarn carrier in an Axminster gripper loom comprising the steps of:

(i) moving a gripper having a gripper body and a gripper jaw to position gripping portions of the gripper body and the gripper jaw on opposite sides of a tail of yarn held in a yarn carrier;

(ii) driving the gripper jaw about a pivotal connection defined by mutually engageable connectors formed on the gripper body and the gripper jaw so as to move the gripping portions towards one another and thereby close the gripper about the tail of yarn; and

(iii) moving the gripper to withdraw a predetermined length of yarn from the yarn carrier.

9. A method of picking up a tail of yarn and withdrawing a predetermined length of the yarn from a yarn carrier in an Axminster gripper loom comprising the steps of:

(i) moving a gripper having a gripper body and a gripper jaw to position gripping portions of the gripper body and the gripper jaw on opposite sides of a tail of yarn held in a yarn carrier;

(ii) driving the gripper jaw about a pivotal connection between the gripper body and the gripper jaw so as to move the gripping portions towards one another and thereby close the gripper about the tail of yarn, the gripper jaw being formed to define a resilient lever to increase the gripping force of the gripper when actuated; and

(iii) moving the gripper to withdraw a predetermined length of yarn from the yarn carrier.

10. A method of weaving a carpet comprising the steps of:

(i) holding pluralities of yarns in a plurality of yarn carriers for selective presentation to a plurality of grippers;

(ii) selectively moving each of the yarn carriers to present a chosen yarn to a respective one of the grippers;

(iii) operating each gripper to pick up the tail of the chosen yarn and withdraw a predetermined length of the chosen yarn from the respective yarn carrier, each gripper being operated to pick up the tail of yarn and withdraw a predetermined length of the yarn from the respective yarn carrier in accordance with Claim 8 or Claim 9;

(iv) cutting each of the chosen yarns such that each gripper holds a tuft of yarn;

(v) operating each gripper to transfer the tufts of yarn to weaving positions in a carpet; and

(vi) securing each tuft of yarn in position within the carpet by means of a weaving process.

Drawing