GB2286601A

GB2286601A - Gripper axminster loom

Info

Publication number: GB2286601A
Application number: GB9502805A
Authority: GB
Inventors: John Dalton Griffith; Richard Donald Stewart
Original assignee: ULSTER CARPET MILLS; Griffith Textile Machines Ltd
Current assignee: ULSTER CARPET MILLS; Griffith Textile Machines Ltd
Priority date: 1994-02-18
Filing date: 1995-02-14
Publication date: 1995-08-23
Anticipated expiration: 2015-02-14
Also published as: GB2286601B; BE1008440A5; GB9403185D0; GB9502805D0

Abstract

A gripperAxminster loom has a plurality of yarn carriers (1) mounted for reciprocation, in use of the loom, between a selected first position in which a required yarn can be taken from the carrier, and a second or rest position, and means operable on detection of a fault to move a selected carrier from its second position independently of the other carriers for access for repair. The carriers are reciprocated by a shaft (5) which is normally driven through a cam by a further shaft. On detecting a fault however the latter shaft is stopped and the shaft (5) is driven instead by means such as an air cylinder while the carrier detected as being faulty is coupled by electromagnetic means (3) for displacement by the shaft to the repair position. <IMAGE>

Description

LOOM The present invention relates to looms and more particularly, although not exclusively, to an Axminster carpet weaving loom.

In an Axminster carpet weaving loom, for each tuft inserting position a plurality of different coloured yarns are fed to a common yarn guiding bar or carrier, which bar or carrier is reciprocated (for example raised and lowered) to different positions to enable selection of a desired coloured yarn. A gripper is operable to select a required pile yarn held in the guiding bar or carrier and the gripper withdraws a length of yarn therefrom. The length of yarn is then cut and the gripper transfers the cut yarn length to the weaving area of the loom where it is placed in the carpet during the weave process.

Grippers and carriers are mounted across the loom, one pair for each pile row of the carpet. Accordingly, there are a large number of grippers and carriers in a given loom. The carriers may be either horizontal or vertical. The selection of the correct yarn pile may be performed by an electronic tuft selector as disclosed in EP-A-0420869.

A gripper may fail to pick up the selected yarn pile from the carrier. This failure may be detected by a tuft detector which causes the loom to stop.

The principle cause of a gripper failing to grip a required pile yarn is that the latter does not present an end that can be grasped by the gripper. As there may be upwards of one thousand carriers in a loom, it can take some considerable time for the operator to locate the carrier with the faulty yarn end in a loom which does not embody tuft fault detectors. Even in looms having tuft fault detectors, considerable time is spent in accessing the faulty carrier.

It is an object of the present invention to reduce significantly the time taken to repair a faulty carrier.

According to one aspect of the present invention there is provided a loom having a plurality of yarn carriers mounted for reciprocation, in use of the loom, between a selected first position in which a required yarn can be taken from the carrier, and a second position, and means operable to move a selected carrier from its second position independently of the other carriers for access for repair.

Preferably, the loom further comprises control means, such as a computer or other processor, the control means being responsive to means detecting a faulty carrier and thereupon rendering the loom inoperative, and then commanding operation of the means associated with the faulty carrier to move that carrier from its second position.

A faulty carrier may be moved to its extreme first position furthest from its second position in order to make that carrier as accessible as possible for manual repair. However, the present invention lends itself to the use of automatic repair means and if such are employed, it may be preferable to move the faulty carrier to the position in which the pile yarn was not previously available and which gave rise to the fault condition. A loom in accordance with the present invention may thus embody automatic repair means.

According to another aspect of the present invention, there is provided a method of controlling a loom comprising a plurality of yarn carriers, comprising the steps of: 1) detecting when a yarn carrier is faulty, 2) rendering the loom inoperative upon the detection of a faulty carrier, 3) moving the faulty carrier from a rest position to a position in which access can be gained to the faulty carrier for repair.

The moving step may involve moving the faulty carrier to a first position which is furthest from the second position, or moving it to the previously selected first position which gave rise to the fault condition. In either instance, the method may comprise the further step of rendering operative automatic repair means which will go to the faulty carrier in its first position and effect the necessary repair.

A loom embodying the present invention will now be described in greater detail, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic end elevation of a typical gripper and carrier arrangement for a loom, and Figure 2 is a diagrammatic end elevation of means operable independently to move the tuft selector when the loom has stopped, in accordance with the present invention, and Figure 3 is a block diagram of the loom control means.

Referring first to Figure 1 of the drawings, this illustrates a single yarn guiding bar or carrier 1, of which there are many (typically upwards of 1000) in the loom. The carrier 1 is selectively moved by a tuft selector mechanism 3 which may be similar to that described in EP-A-0420869, the disclosure of which is incorporated herein by reference. The tuft selector 3 is reciprocated by an oscillatory shaft 5 and associated lever 6 and connecting rod 7 between a rest or second position and a selected first position. The first position of the carrier 1 is determined by a detent in the form of a spring finger 8 which, when released by an electricallycontrolled magnet mechanism 11, drops into a selected notch 9 in the carrier in order to determine which of the pile yarns 2 is aligned with the gripper 4 for gripping by the latter.Once gripped, the selected yarn is pulled, cut and transferred to the loom at 4a. The carrier 1 is biased by a spring 10 to the rest or second position.

The oscillatory shaft 5 is common to all the carriers 1 and is selectively driven by two independent drive means. The first drive means comprises a cam mechanism comprising a drive shaft 21, a cam 20 and a cam follower 22 (Figure 2). The drive shaft 21 is driven in synchronism with the main drive shaft of the loom. The cam follower 22 is rotatably mounted at one end of an arm 23 which is fixed at its other end to the shaft 5. The second drive means for oscillating shaft 5 comprises a piston rod 24 which is pivotally attached to arm 23. The piston rod 24 extends from a piston 25 of a double-acting pneumatic cylinder 26. The cylinder 26 is pivotally mounted on the frame of the loom at 27 and has two ports 28 and 29.

During normal operation of the loom, the shaft 21 continually rotates so that the arm 23 is continuously raised and lowered by the cam 20, whereby the shaft 5 is reciprocated. At this time, compressed air is fed into the cylinder 26 through the port 28, and port 29 is open to atmosphere. Thus, the cylinder 26 is converted to an air spring against which the cam 20 acts and which biases the arm 23 downwardly as seen in Figure 2.

Referring now to Figure 3, when a tuft is not picked up by a particular gripper 4, an associated detector 31 sends a signal to a control unit 32, such as a computer, so that the control unit knows at which carrier the fault has occurred. The computer 32 then initiates the stopping of the loom which means the drive shaft 21 is arrested so that a carrier 1 would not move even if the associated tuft selector were to be operated.

Preferably the shaft 21 is stopped at a position whereat the carriers 1 are located at their second positions, as for example shown in Figure 2. The requirement is now for the faulty carrier alone to be moved from its rest or second position. This is accomplished by feeding compressed air to the port 29 of the cylinder 26, under the control of the computer 32, to raise the arm 23 and hence rotate the shaft 5. At the same time, the tuft selector 3 of the faulty carrier is operated so as to drop the detent 8 into one of the notches 9 so that the faulty carrier alone is moved from its rest or second position to a first position in which it is accessible for manual or automatic repair.

After repair, port 29 is vented and compressed air is fed into cylinder 26 via port 28 in order to return the faulty carrier to its second position.

If manual repair is being effected, it is usually preferred to have the faulty carrier as far removed from the others as possible so that the detent 8 would be engaged with the extreme right-hand notch 9 as seen in Figure 1. If automatic repair is being carried out, then it might be preferable to move the faulty carrier 1 to the position in which the fault occurred so that the detent 8 would be engaged with the appropriate notch 9.

It will be appreciated that the present invention enables a faulty carrier to be moved to a position for repair independently of the other motions of the loom.

It will be appreciated that instead of using compressed air for moving piston 25, other fluids may be adopted.

Claims

1. A loom having a plurality of yarn carriers mounted for reciprocation, in use of the loom, between a selected first position in which a required yarn can be taken from the carrier, and a second position, and means operable to move a selected carrier from its second position independently of the other carriers for access for repair.

2. A loom according to claim 1 wherein said plurality of yarn carriers are selectively driven by a common oscillatory shaft, the oscillatory shaft being selectively driven by two independent drive means.

3. A loom according to claim 2 wherein one of the independent drive means comprises a continuously rotating drive shaft which is driven in synchronism with a main drive shaft of the loom.

4. A loom according to claim 3 including a cam mounted on the continuously rotating shaft, the oscillatory shaft having an arm carrying a cam follower biased into engagement with the cam so as to cause oscillatory motion of the oscillatory shaft on rotation of the cam.

5. A loom according to claim 4 wherein the other independent drive means comprises a drive means which is operable to move the cam follower away from the cam.

6. A loom according to claim 5 wherein the other independent drive means comprises a fluid operated piston connected to the oscillatory shaft, the piston being selectively movable between a first and second position, the piston when at said first position acting to resiliently urge the cam follower into contact with the cam, the piston being movable to its second position to move the cam follower away from the cam.

7. A loom according to claim 6 wherein the piston is connected to the oscillatory shaft via said arm carrying the cam follower.

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

9. A method of controlling a loom comprising a plurality of yarn carriers, comprising the steps of: 1) detecting when a yarn carrier is faulty, 2) ; rendering the loom inoperative upon the detection of a faulty carrier, 3) moving the faulty carrier from a rest position to a position in which access can be gained to the faulty carrier for repair.

10. A method according to claim 9 wherein the moving step involves moving the faulty carrier to a first position which is furthest away from the second position.

11. A method according to claim 9 wherein the moving step involves moving the faulty carrier to the selected first position which gave rise to the fault condition.

12. A method according to claim 9,10 or 11 further including the step of rendering operative automatic repair means to move to the faulty carrier in its first position and effect the necessary repair.

13. A method of controlling a loom substantially as herein described with reference to the accompanying drawings.