GB2428048A

GB2428048A - Gripper for Axminster loom with profiled pivot area

Info

Publication number: GB2428048A
Application number: GB0513137A
Authority: GB
Inventors: Stuart Russell
Original assignee: Griffith Textile Machines Ltd
Current assignee: Griffith Textile Machines Ltd
Priority date: 2005-06-28
Filing date: 2005-06-28
Publication date: 2007-01-17
Also published as: BE1017448A5; GB0513137D0

Abstract

A gripper (10) for an Axminster gripper loom comprising a gripper body (12) and a gripper jaw (14), the gripper body and gripper jaw being pivotally connected by a pivot connection (16) for pivotal movement about a fixed pivot axis and each being formed from sheet material into a desired profile, the profile of one of the gripper body and gripper jaw being shaped to define a first pivot formation and the profile of the other of the gripper body and gripper jaw being shaped to define a second pivot formation, the first and second pivot formations being inter-engageable to define said pivot connection. The gripper body and the jaw may be made from metal and may be stamped from a blank. The engagement means may also include one or more tongue and depressions (44, 26 Figs 3 and 4) to aid engagement of the body and jaw and resist twisting of the parts. The body and the jaw may be connected by flexible connection strip (70 Fig 5) to bias the body and jaw about the pivot axis.

Description

A GRIPPER

The present invention relates to a gripper fbr an Axminster gripper loom and an Axminster gripper loom incorporating the gripper.

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.

When at the yarn supply, the gripper undergoes a closing operating 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 it has been caught in the carpet weave.

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.

Each gripper includes a gripper body and a gripper jaw pivotally coniected to the gripper body by means of a 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.

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.

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

According to an aspect of the invention there is provided a gripper for an Axrninster gripper loom comprising a gripper body and a gripper jaw, the gripper body and gripper jaw being pivotally connected by a pivot connection for pivotal movement about a fixed pivot axis and each being formed from sheet material into a desired profile, the profile of one of the gripper body and gripper jaw being shaped to define a first pivot formation and the profile of the other of the gripper body and gripper jaw being shaped to define a second pivot formation, the first and second pivot formations being inter-engageable to define said pivot connection.

Embodiments of the invention will now be described, by way of nonlimiting examples, with reference to the accompanying drawings in which: Figure 1 shows a gripper according to an embodiment of the invention in an open position; Figure 2 shows the gripper of Figure 1 in a closed position; Figure 3 shows a gripper body of the gripper of Figure 1; Figure 4 shows a gripper jaw of the gripper of Figure 1; and Figure 5 shows a gripper according to a further embodiment of the invention in an open position.

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

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 connection 16 for pivotal movement about a fixed pivot axis between an open position (Figure 1) and a closed position (Figure 2)10 enable the gripper 10 to grip a yarn (not shown).

Each of the gripper body 12 (Figure 3) and the gripper jaw 14 (Figure 4) is formed from sheet material into a desired profile. The profile of the gripper body 12 is shaped to define a first pivot formation and the profile of the gripper jaw 14 is shaped to define a second pivot fonnation, the first and second pivot formations being inter-engageable to define the pivot connection 16.

in the embodiment shown in Figure 1, the gripper body 12 is formed to define a fixing portion 18 (Figure 3) to mount the gripper 10 in an Axrninster loom (not shown). At its other end, the gripper body 12 defines a gripping portion 20 and, between the two ends, is shaped to define a protrusion 22 the terminal end of which has a rounded profile to define a journal.

Two staggered depressions 26,28 are preferably formed on the opposite faces 3032 of the gripper body 12 between the protrusion 22 and the gripping portion 20, and the gripper body 12 is also preferably shaped to define a tongue 24 protruding laterally from one face 30 of the gripper body 12 between the protrusion 22 and the fixing portion 18.

In the embodiment shown in Figure 1, the gripper jaw (Figure 4) is 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, defines a recess 38 shaped to rotatably receive the journal of the protrusion 22 defined by the profile of the gripper body 12.

Two staggered tongues 42,44 preferably protrude laterally from opposite faces 46,48 of the gripper jaw 14 between the recess 38 and the gripping portion 36, and the gripper jaw 14 is also preferably shaped to define a depression 40 in one face 46 of the gripper jaw 14 between the recess 38 and the connection portion 34.

The gripper body 12 and the gripper jaw 14 are preferably formed from a sheet material by a stamping or profile cutting operation. The sheet material may be a hardened and tempered spring steel.

It is envisaged that in other embodiments, the profile of the gripper jaw 14 may he formed to define the protrusion 22 and the profile of the gripper body may be formed to define the recess 38 to rotatably receive the protrusion 22.

Similarly, in other embodiments, it is envisaged that the profiles of the gripper body 12 and the gripper jaw 14 may he varied to provide different combinations of tongues and depressions.

The protrusion 22 on the gripper body 12 and the recess 38 on the gripper jaw 14 are preferably located such that. on assembly of the gripper 1 0, the protrusion 22 is aligned with the recess 38.

Similarly, the tongues 42,44 protruding from the gripper jaw 14 and the tongue 24 protruding from the gripper body 12 are also preferably located such that, on assembly of the gripper 10, the tongues are aligned with the depressions 26,28 and formed in the gripper body 12 and gripper jaw 14 respectively.

During assembly of the gripper 10, the gripper jaw 14 is preferably positioned relative to the gripper body 12 such that the protrusion 22 is rotatably received in the recess 38, the tongue 24 is received in the corresponding depression 40 and the tongues 42,44 are aligned with open ends of the depressions 26,28.

The relative shapes of the gripper body 12 and the gripper jaw 14 are preferably chosen such that 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 with open ends of the depressions 26,28.

Once the tongues 42,44 and depressions 26,28 are aligned, the gripper jaw 14 is rotated relative to the gripper body 12 such that each of the tongues 42,44 slides into the respective depression 26,28. 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. The gripper jaw 14 cannot then be disconnected from the gripper body 1 2 without twisting the connection portion 34 of the gripper jaw 14 to cause it to overlie the fixing portion IS of the gripper body 12.

During opening and closing of the gripper 1 0, the tongues 24 and 42,44 slide in and out of respective depressions 40 and 26,28. The lengths of the tongues 24 and 42.44 and the respective depressions 40 and 26,28 are preferably chosen such that the ends of tongues 24 and 42,44 are retained within the respective depressions 40 and 26,28 when the gripper 1 0 is in its closed/open position respectively, as shown in Figures 1 and 2.

Such engagement of the tongues 42,44 in depressions 26,28 prevents disengagement of the protrusion 22 from recess 38 through lateral and longitudinal movement of the gripper body 12 relative to the gripper jaw 14.

Similarly engagement of tongue 24 formed on the gripper body in the depression formed on the gripper jaw 14 prevents disengagement of the protrusion 22 from recess 38 through longitudinal movement of the gripper body 12 relative to the gripper jaw 14.

Engagement of the tongue 24 formed on the gripper body 12 in the depression 40 formed in the gripper jaw 14 also preferably limits pivotal movement of the connection 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.

In other embodiments it is envisaged that the profiles of the gripper body 12 and the gripper jaw 14 may be varied to provide different combinations of tongues and depressions to resist lateral and/or longitudinal movement of the gripper body 12 relative to the gripper jaw 14.

A gripper 50 according to a further embodiment of the invention is shown in Figure 5.

The gripper 50 includes a gripper body 52 and a gripper jaw 54 pivotally connected to the gripper body 52 by means of a pivot connection 56 for pivotal movement about a fixed pivot axis between an open position, as shown in Figure 5, and a closed position (not shown) to enable the gripper 50 to grip a yarn (not shown).

Each of the gripper body 52 and the gripper jaw 54 is formed from sheet material into a desired profile. The profile of the gripper body 52 is shaped to define a first pivot formation and the profile of the gripper jaw 54 is shaped to define a second pivot formation, the first and second pivot formations being inter-engageable to define the pivot connection 56.

In the embodiment shown in Figure 5, the gripper body 52 is formed to define a fixing portion 58 to mount the gripper 10 in an Axminster loom (not shown). At its other end, the gripper body 52 defines a gripping portion 60 and, between the two ends, is shaped to define a protrusion 62 the terminal end of which has a rounded profile to define a journal.

In the embodiment shown in Figure 5, the gripper jaw 54 is formed to define a connection portion 64 to engage a mechanical drive means (not shown), which, in use, controls the opening operation of the gripper 50. At its other end, the gripper jaw 54 defines a gripping portion 66 and, between the two ends, defines a recess 68 shaped to rotatably receive the journal of the protrusion 62 defined by the profile of the gripper body 52.

in other embodiments it is envisaged that the profile of the gripper body 52 may be shaped to define the recess 68 and the profile of the gripper jaw 54 may be shaped to define the protrusion 62.

In the embodiment shown in Figure 5, a flexible connection strip 70 integrally interconnects the gripper body 52 and the gripper jaw 54.

The gripper body 52, the gripper jaw 54 and the integral cotmection strip 70 are preferably formed integrally from a sheet material by a stamping or profile cutting operation. The sheet material may be a hardened and tempered spring steel.

Preferably the connection strip 70 extends between gripping portions 60, 66 of the gripper body 52 and the gripper jaw 54 such that when the protrusion 62 formed on the gripper body 52 is received in the recess 68 defined by the gripper jaw 54, the connection strip 70 is folded between the gripping portions 60,66.

In this folded configuration. the connection strip 70 acts to bias the gripper body 52 and the gripper jaw 54 in a desired rotary direction about the pivot axis.

The connection strip 70 also acts in this configuration to prevent disengagement of the first and second pivot formations.

o In the embodiment shown in Figure 5, the connection strip 70 is arranged such that it acts to bias rotation of the gripper body 52 and the gripper jaw 54 towards an open position.

It is envisaged that in other embodiments, the connection strip 70 may be arranged such that it acts to bias rotation of the gripper body 52 and the gripper jaw 54 towards a closed position.

It is also envisaged that in yet further embodiments, the connection strip 70 may be arranged such it acts to bias rotation of the gripper body 52 and the gripper jaw 54 towards a position mid-way between the open and closed positions.

Claims

1. A gripper for an Axminster gripper loom comprising a gripper body and a gripper jaw, the gripper body and gripper jaw being pivotally coirnccted by a pivot connection for pivotal movement about a fixed pivot axis and each being formed from sheet material into a desired profile, the profile of one of the gripper body and gripper jaw being shaped to define a first pivot formation and the profile of the other of the gripper body and gripper jaw being shaped to define a second pivot formation, the first and second pivot formations being inter-engageable to define said pivot connection.

2. A gripper as claimed in Claim 1 wherein the gripper body and the gripper jaw are formed from a sheet material by a stamping or profile cutting operation.

3. A gripper as claimed in Claim I or Claim 2 wherein the first pivot formation includes a protrusion, the terminal end of which has a rounded profile to define a journal, and the second pivot formation includes a recess shaped to rotatably receive the journal of the first pivot formation for rotation about a fixed axis.

4. A gripper as claimed in any one of the preceding claims wherein the gripper body and the gripper jaw are formed to define complementary engagement means which are inter-engageable on engagement of the first and second pivot formations to resist lateral and/or longitudinal movement of the gripper body relative to the gripper jaw.

5. A gripper as claimed in Claim 4 wherein the complementary engagement means includes at least one tongue protruding laterally from one face of one of the gripper body and the gripper jaw and a depression formed in one face of the other of the gripper body and the gripper jaw such that on engagement of the first and second pivot ibrmations the tongue is slidably received in the depression.

6. A gripper as claimed in Claim 5 wherein the complementary engagement means includes a pair of staggered tongues protruding laterally from opposite faces of one of the gripper body and the gripper jaw and a pair of staggered depressions formed in opposite faces of the other of the gripper body and the gripper jaw, the staggered tongues and depressions being arranged on one side of the pivot axis such that on engagement of the first and second pivot formations the tongues are slidahly received in the depressions.

7. A gripper as claimed in Claim 6 wherein the complementary engagement means further includes a third tongue protruding laterally fTom a face of one of the gripper body and the gripper jaw and a third depression formed in a face of the other of the gripper body and the gripper jaw, the third tongue and depression being arranged on the opposite side of the pivot axis to the staggered tongues and depressions such that on engagement of the first and second pivot formations the third tongue is slidably received in the third depression.

8. A gripper as claimed in any one of Claims 1-4 wherein the gripper body and the gripper jaw are integrally connected to one another by a flexible connection strip formed from the sheet material.

9. A gripper as claimed in Claim 8 wherein the flexible connection strip acts to bias the jaws in a desired rotary direction about the pivot axis.

1 0. An Axminstcr gripper loom including a plurality of grippers as claimed in any one of Claims 1 -9.

11. A gripper generally as herein described with reference to and/or as illustrated in the accompanying drawings.