GB2389122A

GB2389122A - Axminster gripper loom

Info

Publication number: GB2389122A
Application number: GB0312413A
Authority: GB
Inventors: John Dalton Griffith
Original assignee: Griffith Textile Machines Ltd
Current assignee: Griffith Textile Machines Ltd
Priority date: 2002-05-31
Filing date: 2003-05-30
Publication date: 2003-12-03
Anticipated expiration: 2023-05-30
Also published as: GB0212660D0; BE1016319A3; GB0312413D0; GB2389122B

Abstract

The Axminster gripper loom includes a number of tuft yarn grippers 2, each of which is operable to undergo a cyclic operation involving collecting a tuft from a tuft supply and depositing the collected tuft at a weaving position in the loom, and a selectively actable control system which is arranged to control the operation of the grippers. A weft yarn sensing system is arranged to detect a breakage in the weft yarn and are operable, upon sensing a breakage, to actuate the control system to render the grippers inoperable for collecting and/or depositing tufts. The loom also preferably includes a mechanical drive system for the grippers which can be selectively disengaged and a mechanism to allow the drive connection between the drive system and the grippers to be selectively disconnected. The drive system may include a toggle system 7 that in one position maintains the grippers in a closed position, the toggle mechanism being driven by a drive element that can be moved in and out of engagement with the toggle mechanism while an independent drive mechanism which opens and closes the grippers is operable, on detection of the weft yarn breakage, to prevent operation of the grippers. Also claimed is a method of operating an Axminster gripper loom.

Description

fYMINSTER GRIPPER LOOM The present invention relates to an Axminster

gripper loom and a method of controlling an Axminster gripper loom.

s Len Axminster gripper loom includes a row of grippers each of which collects a tuft of yarn from a yarn supply and transfers the tuft tuna weaving position of the loom for \veaving into the carpet. 'I'ypieally for each pick of the loom, each gripper undergoes a cycle of motion which involves the pro gripper moving to the yam supply, then to the weaving position, anti then returning to the yarn SUPPIY.

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 Is to the weaving position and then undergoes an opening operation to release the tuft after is has been caught.,n the carpet weave.

In an Axminster loom, the grippers automatically move through the cycle of mot on anal opening and closing opcrtiors normally under the direct 20 motive drive from the mailer drip c shaft of tl',e loom In the weave, each tuft is wrapped about a weft yarn. If during veaving the weft yarn breaks, the thefts presentect to the weaving position are not anchored into the weave due to the absence of a weft yarn, and so are freely as deposited by the grippers \vhen they undergo their opening operation.

I ypically an Axminster loom ncluies a weft yam breakage detector which Oven sensing a broken \vett yarn is operable to stop the loom.

Untorttnately, as the speed of operation of an Axminster loom is increased, 3' the inertia of the loom is such that after the breakage detector has actuated a l

! loom stop, one or more 'over-run' picks are procluccl Since there is no weft yarn being inserted during these ovcr-nm picks, the grippers present and release unwantcci tufts which are freely deposited at the weaving position of the loom.

Once the loom has stopped, it is necessary for an operative to remove these unwanted freely deposited tufts and reverse the loom to the pick at which the weft breakage occurrc<l. This is a very tic consuming operation and is wasteful in loss of tuft yarn.

This problem of the production and creation of unwanted tufts occurring during over-nn picks bccones an even bigger problem as the speed of operation of the Axminstcr looms becomes t'astcr.

Is It is a general aim of the present ivcntion to provide an Axminster gripper loom, and a methyl of operating an Axminstcr gripper loom, which avoids problems associated with unwanted tufts being created during overrun of a loom when stopping after a weft brcalcapc has been detectcl.

to According to an aspect of the invention there is pro\dded an Axminstcr gripper loom including a plurality of tuft yen, grippers, each gripper being operable to undergo a cyclic operation involving collecting a tuft prom a tuft supply and depositing the collected tuft at a weaving position in the loom, selectively actuatable control means arranged to control performance of said :5 cyclic operation of the grippers, and weft yarn sensing means arranged to detect a breakage in the weft yarn, the sensing means on sensing a weft yarn breakage being operable to actuate said control means to render inoperable said cyclic operation of the grippers

According to another aspect of the invention there is provided an Axminstcr gripper loom including a plurality of tuft yarn grippers, each gripper being operable to undergo a cyclic operation involving collecting a tuft from a tuft supply and depositing the collcctcl tuft at a weaving position in the loom, 5 selectively actuatable control means arranged to control performance of said cyclic operation of the grippers, and weft yarn sensing means arranged to detect a breakage in the weft yang, the sensing means on sensing a weft yarn breakage being operable to activate said control means to render the grippers inoperable for collecting and/or depositing tufts.

lo According to yet another aspect of the invention there is provided a method of operating an Axminstcr gripper loom, the method including monitoring weft insertion in order to determine when a breakage occurs in the weft yarn and, on detecting the prcscncc of breakage in the weft yarn, controlling Is the grippers of the loom to render them inoperable for collecting and/or depositing tufts.

Various aspects of the present invention are hereinafter clcscribcd with refcrcncc to the accompanying drawings. In which: Figures I and 2 illustrate how gripper deposits a tuft at a weaving point in a carpet during normal weaving; Figure 3 illustrates deposit of an unwanted tuft after breakage of a weft Is yarn; Figures 4-7 illustrate operation of a gripper In accordance with a first embodiment of the nvcntion; and

Figure 8 illustrates operation of a gripper in accordance with a second embodiment of the invention.

As illustrated in Figures I and 2, during normal operation of an Axminster s gripper loom a gripper 2 presents a tuft I to a weaving position, a weft yam 3 is inserted, and the reed 4 of the loom beats the weft 3 into the carpet trapping a first leg Lit of the tuft I (Figure I).

The gripper 2 then undergoes an opening operation to release the tuft 1 and lo at the same time moves forwardly and upwardly to cause the remainder of the tuft 1 to rise and form its second leg Lo.

lowever, as Illustrated in Figure 3, If there is no weft yarn 3 present due to a yarn breakage, the first leg 1 ' of a presented tuft 1 is not trapped in the Is weave so that subsequently, as the gripper undergoes its opening operation and forward/upwarl movement, the tuft I is freely deposited on to the carpet. This is typically what happens when a weft yarn breakage is detected and the loom is stopped in order to re-conuect the weft yarn.

However, as the speed of operation of an A.xmmster loom is increased, the so inertia within the loom is such that, on detecting the weft yam breakage, it causes at least one beat-up of the reed before the loom actually stops.

Accordingly it is then necessary, before the loom can be re-started, for all the unwanted finely deposited tufts to be removed manually.

as In accordance with the present invention, the normal cyclic operation of the grippers is controlled such that on detection of a weft yarn breakage, the grippers are rendered inoperable for collecting and/or depositing tufts. This has the effect of isolating at least part of the operation of the grippers from the remainder of the loom and so prevents the deposit of unwanted tufts :o whilst the loom is stopping.

As illustrated in Figure 4, according to a first embodiment of the invention, the opening operation of each gripper 2 is controlled such that on detection of a weft yarn breakage. the opening operation is rendered inoperable. Thus s the gripped tufts remain held by the grippers 2 and are not freely deposited onto the carpet.

It will be appreciated that whilst the grippers 2 arc maintained In their closed condition, they will not collect any new tufts when presented to the lo tuft yarn supply and so it is possible for the loom to run past beat up without causing deposit of any unwanted tufts.

In one particular arrangement (see Figures 5-7) the opening operation of each gripper 2 is controlled by a mechanical drive means linked to a pneumatically actuated disengagement means.

As illustrated in Figure 5, each gripper 2 comprises a gripper body 5 and a gripper jaw 15 pivotally connected to the gripper body 5 by means of a pivot 6.

The gripper body 5 of each gripper 2 is secured, by means of a clamping system 13, to a gripper mounting tube 12 that extends across the loom.

A shaft 11 located within the gripper mounting tube 12 is provided with a as radially extending tongue 10 along its length thereof.

The gripper jaw 15 of each gripper 2 engages the tongue 10 such that rotation of the shaft about its elongate axis causes pivotal movement of the gripper jaw 15 and thereby opens and closes the gripper jaw I S. s

A plurality of grippers 2 are mounted along the length of the gripper mounting tube 12, one for each tuft position.

At one or both encls of the shaft 11, a lever 14 is fastened in order to 5 facilitate rotation of the shaft 11 about its elongate axis.

While the or each Iever 14 is connected at one end to the shaft 11, it is pivotally connected at its other end by means of a toggle mechanism 7 to an arm 30 that Is fastened to the gripper mounting tube 12.

The toggle mechanism 7 includes first and second connecting rods 20,21.

The first connecting rod 20 is pivotally connected at one end to the lever 14 by means of a first pivot 22. It is pivotally connected at its other end to an end of the second connecting rod 21 by means of a second pivot 23. 'I'he Is second connecting rod 21 is in turn pivotally connected at its other end to the arm 30 by means of a third pivot 24.

I'he second pivot of the toggle mechanism 7 Is attached to a roller 25 (see Figure 7) located within a track formed in a track member 26. The track so member 26 is in turn connected to a lever 27 b\, means of a hinge 35. The Iever 27 is pivotal about a pivot 28.

In use, the Iever 27 is forced to rotate about pivot 28 by cams (not shown) through followers 29 provided on the Iever 27. This results in movement of as the track member 26, which in turn leads to movement of the track relative to the roller 25.

The shape of the track is such that on rotation of'the lever 27, the roller 25 is caused to move upwards or downwards, clopencding on the direction of JO rotation of the Iever 27.

On downward movement of the roller 25, the toggle mechanism 7 causes the lever 14 to rotate in a clockwise direction, thereby moving the tongue 10 such that the gripper jaw 15 closes, as shown in Figure 5.

On upward movement of the roller 25, the toggle mechanism 7 causes the lever 14 to rotate in an anti-clockwise direction, thereby moving the tongue 10 such that the gripper jaw 15 opens, as shown in Figure 6.

lo Referring now to Figure 77 it can be seen that the track member 26 is secured to the lever 27 by means of a hinge 35.

An air cylinder 3fj is connected at one end to the track member 26 by means of a bracket 39, and is connected at its other end to the lever 27 by means of 5 another bracket 40.

On detection of a break in the weft yarn, the air cylinder 36 contracts causing the track member 26 to pivot about hinge 35, away from the roller 25, as shown In dashed lines in Figure 7.

When the track member 26 is located in this position, the roller 25 rests on an abutment 42 provided on arm 3), and the toggle mechanism maintains the gripper jaw 15 closed.

2s It will be appreciated that as the loom stops, the gripper 2 and the lever 27 will continue to move. During such movement however the gripper jaw 15 will remain closed.

When the loom and gripper motions are reversed to return the grippers to their lower position, the track member 26 is moved back to a position where the roller 25 Is located within the track.

5 In other arrangements, the opening operation of each gripper 2 may be controlled by a non-mechanical drive means i.e. independent Virile means which generate motive power independently of the main drive shaft of the loom, such as a servo drive or a pneumatic actuator.

to With such an arrangement, the independent dove means are controlled, for example by electronic means, to cause the opening/closing operation of the grippers to be internptel on detection of a weft yarn breakage.

As illustrated in Figure 8, in accordance with a second embodiment of the is invention, the cyclic motion of the grippers 2 between the tuft yarn supply and the weaving point is controlled such that on detection of a weft yarn breakage the cyclic motion is interrupted causing the grippers 2 to stop before reaching their opening position. thus, as Illustrated m Figure 8, the grippers 2 remain at a position whereat tufts I remain gripped, whilst the 20 remainder of the loom is running as it comes to a stop.

in such an embodiment, movement of each gripper 2 and the opening operation of each gripper 2 may be controlled such that they are mechanically linked, anal arc disengageable from the other weaving as components of the loom.

This may be achieved, for example, by controlling movement of each gripper 2 and the opening operation of each gripper 2 together by means of a servo motor, or by mechanical means such as a disengagement clutch and 30 brake.

The second embodiment is particularly suited for gripper looms wherein the cyclic motion of the grippers is mechanically linked to the opening and closing operations of the grippers.

s It will be appreciated that the present invention enables a loom, particularly a high speed loom, to be stopped and then rc-started rapidly without creating a fault in the carpet in the event of a weft yarn break.

Claims

1. An Axminster gripper loom including a plurality of tuft yarn grippers, each gripper being operable to undergo a cyclic operation involving s collecting a tuft from a tuft supply and depositing the collected tuft at a weaving position in the loom, selectively aetuatable control means arranged to control performance of said cyclic operation of the grippers, and weft yarn sensing means arranged to detect a breakage in the weft yarn, the sensing means on sensing a weft yarn breakage being operable to actuate lo said control means to render the grippers inoperable for collecting and/or depositing tufts.

2. A gripper loom according to Claim I including mechanical drive

means drivingly connected to the grippers so as to cause opening and 15 closing of said grippers, and selectively actuated dsengagemcnt means for disconnecting the driving connection between the mechanical drive means and the grippers on actuation of the disengagement means.

3. A gripper loom according to Claim 2 wherein the mechanical drive to means includes a toggle mechanism which in one toggle position maintains the grippers in a closed position, the toggle mechanism being driven by a drive member, the drive member being moved into and out of engagement with the toggle mechanism by said disengagement means.

as

4. A gripper loom according to Claim I including independent drive means for causing opening/closing of the grippers, the independent drive means being operable, on detection of a wcit yarn breakage, to render inoperable the opening/closing operation of the grippers.

5. A gripper loom according to Claim 1 wherein the control means is Operable to cause the cyclic movement of the grippers bctwcen the tuft supply and weaving position to be intcmptcd.

5

6. A method of operating an Axminstcr gripper loom, the method including monitoring weft insertion in order to determine when a breakage occurs in the weft yarn and, on detecting the presence of a breakage in the weft yarn, controlling the grippers of the loom to render them inoperable for collecting and/or depositing tufts.

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