GB2411663A

GB2411663A - A gripper Axminster loom

Info

Publication number: GB2411663A
Application number: GB0404921A
Authority: GB
Inventors: David Thompson; John Dalton Griffith
Original assignee: Griffith Textile Machines Ltd
Current assignee: Griffith Textile Machines Ltd
Priority date: 2004-03-05
Filing date: 2004-03-05
Publication date: 2005-09-07
Anticipated expiration: 2024-03-05
Also published as: GB0404921D0; GB2411663B

Abstract

A gripper Axminster loom including a plurality of grippers (3) mounted along an elongate gripper carrier (23), drive means (50) for moving the carrier to move the grippers cyclically through a sequence of pre-defined positions, the drive means including electronically controllable adjustment means for varying the location of at least one of said pre-defined positions. Preferably carrier is rotatable about is longitudinal axis and the drive has an oscillatory output and is connected to the carrier via a link (21) of adjustable length.

Description

2411 663 The present invention relates to a gripper loom, in particular,

an Axminster gripper loom and also to a drive mechanism for moving the grippers of such a loom.

According to one aspect of the invention there is provided a gripper Axminster loom including a plurality of grippers mounted along an elongate gripper carrier, drive means for moving the carrier to move the grippers cyclically through a sequence of pre-defined positions, the drive means lo including selectively electronically controllable adjustment means for varying the location of at least one of said pre- defined positions.

According to another aspect of the invention there is provided a drive system for driving the grippers of a gripper Axminster loom, the drive means being adapted for connection to a carrier shaft on which the grippers are mounted, the drive system including drive means arranged to move the carrier shaft through a sequence of successive angular positions, and electronic control means operable on the drive means to selectively adjust selected ones of said angular positions.

According to another aspect of the invention there is provided a method of weaving a carpet on a gripper loom having a plurality of grippers mounted along an elongate gripper carrier, the method including moving the carrier in order to cyclically move the grippers through a sequence of pre-defined positions, and selectively varying the location of at least one of said pre- defined positions in order to alter the characteristics of the tufts laid into the carpet.

Various aspects of the present invention are hereinafter described with so reference to the accompanying drawings, in which: Figure 1 is a schematic end view of a first embodiment according to the present invention showing the grippers in a tuft collection position; Figure 2 is a view similar to that of Figure 1 showing the first embodiment at a different position; Figures 3 to 5 illustrate a gripper at different pre- defined positions in a weaving cycle; Figure 6 is a part perspective view of a second embodiment according to the present invention; Figure 7 is an end view of the embodiment shown in Figure 6; 0 Figure 8 is a schematic end view of a third embodiment according to the present invention.

Referring initially to Figures 1 and 2 there is shown a row of grippers 3 (only one of which is visible) mounted on a gripper carrier shaft 23.

The shaft 23 is rotatably mounted in the frame (not shown) of the loom and is moved to successive pre-defined angular positions by a drive means 50.

A pair of drive means 50, one located at each end of shaft 23, is preferably provided.

The drive means 50 includes a continuously rotating drive shaft 51 having mounted thereon a pair of cam discs 52. The drive means 50 further includes a driven lever 20 which is mounted for oscillatory motion about a pivot shaft 53. A pair of cam followers 54 are mounted on the lever 20 with the pivot axis of the lever 20 being located therebetween. One of the cam followers 54 is in abutment with one of the cam discs 52 and the other of the cam followers 54 is in abutment with the other cam disc 52.

Accordingly the lever 20 is caused to be positively driven in both rotary so directions about its pivot axis by the cam discs 52 and followers 54.

The cam discs 54 are shaped such that at pre-defined rotary positions of shaft 51, the lever 20 is caused to dwell temporarily.

Accordingly as shaft 51 undergoes one complete revolution, the angular position of the driven lever 20 is changed and is caused to dwell at predetermined positions which correspond to the pre-defined angular positions of the carrier shaft 23.

lo The lever 20 is connected, by a connecting link 21, to a crank arm 22 mounted on the carrier shaft 23 in order to cause the shaft 23 to be moved through the sequence of successive pre-defined angular positions as the shaft 51 undergoes one complete revolution. As indicated in Figures 3, 4 and 5 the sequence of pre-defined angular positions of the carrier shaft 23 includes at least three positions, viz. a tuft collection position (Figure 3), a tuft draw down position (Figure 4) and a tuft laying-in position (Figure 5).

The length of link 21 is selectively adjustable by an electronic control means (not shown). For example the link 21 may be defined by a servo to motor driven ball screw, or a servo hydraulic piston/cylinder, or a linear motor which are actuated in response to the electronic control means.

Accordingly, the connecting link 21 may be actuated by the electronic control means to vary the angular location of the carrier shaft 23 (and hence the grippers 3) when the carrier shaft 23 is at any one of its predefined angular positions.

It is possible therefore to adjust the position of the grippers when at any one of the pre-defined positions (e.g. the tuft collection position, the tuft draw so down position and/or the tuft laying-in position). This adjustment may be made as a setting-up adjustment of the loom, i.e. to accurately define the pre-defined angular positions and so enables a loom to be quickly and accurately set up.

This set up adjustment, for example can be performed prior to weaving on the loom in order to ensure that the grippers reliably pck up tuft yarn, draw down the desired length 't' of yarn 6 for cutting by a cutter 5, and place the tuft in the weave such that the length 'Ig' of the legs of the 'U' tuft are equal.

In addition, the electronic control means may be programmed in accordance with a pre-defined pattern to vary the location of the grippers when at any one of the pre-defined positions in order to produce tufts of different lengths and/or produce inserted tufts having legs of different lengths in order to produce patterning effects in the weave.

For example, on selected picks the electronic control means may be programmed to actuate the link 21 to shorten its effective length so that when the grippers draw down yarn 6, the length of yarn 'I' is shorter than JO normal. Accordingly when the resultant 'short' tuft is inserted in the weave, it will produce a sculptured effect. Actuation of the link 21 by the control means can be performed whilst the shaft 23 moves from the tuft gripping position to the tuft draw down position.

As illustrated in Figure 5, the length 'Ig' of the held tuft loop leg lea can be varied by changing the location of the grippers 3 when at the tuft laying-in position. By creating a relatively longer leg 10_, the tuft loop assumes a 'J' configuration; by creating a shorter leg 10_ the tuft loop assumes the mirror image of a 'J' configuration.

A second embodiment 100 is illustrated in Figures 6 and 7 showing a modified drive means 50. Parts in the second embodiment similar to those in the first embodiment are shown by the same reference numerals.

In embodiment 100, the lever 20 carries an intermediate lever 120 which is pivotally mounted on lever 20 via a pivot 121.

One end of lever 120 is connected to the crank arm 22 in order to transmit drive from shaft 51 to shaft 23.

The opposite end of lever 120 is connected to an adjustment means 300 which serves to adjust the angular position of lever 120 relative to lever 20 and so, in effect, vary the displacement caused by lever 20 when transmitting drive to shaft 23. The adjustment means 300 is selectively Is operable by the electronic control means in a similar manner to link 21 of the first embodiment. The adjustment means 300 may for example be a servo motor driven ball screw, a servo hydraulic piston/cylinder or a linear motor.

A third embodiment 200 is illustrated in Figure 8. In the third embodiment 200, the drive means 50 and adjustment means are defined by actuation means 400 which is selectively controllable by the electronic control means.

The actuation means 400 may for example be a servo piston/cylinder 401, the piston rod 402 of which is directly connected to the crank arm 22. In Is this embodiment, the actuation means moves the shaft 23 through the sequence of predetermined positions and also adjusts the location of these positions in response to the electronic control means.

Claims

1. A gripper Axminster loom including a plurality of grippers mounted along an elongate gripper carrier, drive means for moving the carrier to move the grippers cyclically through a sequence of pre-defined positions, the drive means including selectively electronically controllable adjustment means for varying the location of at least one of said predefned positions.

2. A loom according to Claim 1 wherein the carrier is rotatable about its lo longitudinal axis, the drive means being drivingly connected to the carrier to rotatably move the carrier to move the grippers through said sequence of pre-defined positions.

3. A loom according to Claim 2 wherein the drive means includes a is drive mechanism having an oscillatory drive output drivingly connected to said carrier via a link whose length is selectively adjustable by said adjustment means.

4. A loom according to Claim 3 wherein the link is defined by an to electrically controllable linear actuator.

5. A loom according to Claim 3 wherein the drive means comprises an electrically controllable linear actuator.

6. A loom substantially as herein described with reference to and as illustrated in the accompanying drawings.

7. A method of weaving a carpet on a gripper loom having a plurality of grippers mounted along an elongate gripper carrier, the method including so moving the carrier in order to cyclically move the grippers through a sequence of pre-defined positions, and selectively varying the location of at least one of said pre-defined positions in order to alter the characteristics of the tufts laid into the carpet.

8. A method according to Claim 7 wherein one of said pre-defined positions is a tuft draw down position, the tuft draw down position being selectively varied during weaving to vary the length of tufts being woven.

9. A method according to Claim 7 or 8 wherein one of said pre-defined lo positions is a tuft laying-in position and another of said pre-defined positions is a tuft release position, the tuft laying-in and/or tuft release positions being selectively varied in order to change the relative lengths of the legs of the tufts during weaving.

10. A method of weaving a carpet on a gripper loom substantially as herein described with reference to the accompanying drawings.

11. A drive system for driving the grippers of a gripper Axminster loom, the drive means being adapted for connection to a carrier shaft on which the to grippers are mounted, the drive system including drive means arranged to move the carrier shaft through a sequence of successive angular positions, and electronic control means operable on the drive means to selectively adjust selected ones of said angular positions.