GB1572924A - Carpet looms - Google Patents

Description

(54) IMPROVEMENTS RELATING TO CARPET LOOMS (71) We, BRINTONS LIMITED, a British Company, of Exchange Street, Kidderminster, Worcestershire, DY10 1AG, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to carpet looms of the gripper Axminster type and is particularly concerned with the detection of missing tuft yarns and their subsequent replacement. Our prior patent specification No. 1,089,844 describes and claims a mechanism for detecting the absence of a tuft yarn and for stopping the loom as a result. It is then necessary for the operator to replace the yarn in question before re-starting the loom.Bearing in mind that there are hundreds of tuft yarns across the width of a loom, an appreciable time is required in order to locate the carrier from which yarn is missing. It is then necessary to draw the carrier out by hand into a position in which it is accessible for re-threading. The carrier can then be returned to its normal position and the loom re-started. Although such stoppages are normally relatively infrequent, they can nevertheless occupy an appreciable proportion of the operator's time and slow down the overall production.

According to the present invention, the yarn carriers are divided into a number of groups across the width of the loom, each group being provided with mechanism for withdrawing the carriers of the group into a retracted position and the loom also includes detecting mechanism for sensing a missing tuft yarn in a yarn carrier and operative, in the event of a missing tuft, to stop the loom and to provide a signal for selectively operating the mechanism for withdrawing that group of carriers which includes the carrier having the missing tuft yarn. The withdrawal, of the group of yarn carriers greatly facilitates the identification of the carrier from which the yarn is missing and this may readily be pulled forward by hand into a convenient position for rethreading.By keeping the various movements of the yarn carriers within the normal working range, it is then possible to re-start the loom without the need for any re-setting of the carriers. In this way, the amount of time spent by the operator can be very materially reduced and the overall production increased accordingly. In a particular example, six groups of carriers across a 4 metre width of loom are adequate, each group in this particular example including 184 yarn carriers. Once the group which contains the missing yarn is isolated, there is a very much smaller number of carriers to look through and, as mentioned above, the fact that the group as a whole has been drawn back into a retracted position means that when the faulty carrier has been pulled forward it is clear of all the surrounding carriers and rethreading is facilitated.

A delay device is preferably included between the detecting mechanism and each separate mechanism for withdrawing the group of yarn carriers so as to enable the loom as a whole to come to a standstill before the group of carriers is withdrawn. The detecting mechanism preferably operates as described in the co-pending application No. 34350/77 (Serial No. 1572923) which represents an improvement over that described and claimed in specification No. 1,089,844 referred to above.

As a result of the detecting mechanism being divided into sections across the width of the loom, each section is capable of providing an individual signal in response to a missing.yarn in that section and this signal then operates the mechanism for withdrawing the corresponding group of carriers, i.e. including the carrier with the missing tuft yarn. It is also possible, however, to modify the detector mechanism decribed in specification No.

1,089,844 to operate in a similar manner.

Thus the rocker shaft described in the earlier specification may be divided into a number of separate lengths, each corresponding to an individual group of yarn carriers and each driven independently in a similar manner to that described. The absence of a tuft yarn then stops only the associated length of rocker shaft and the closing of the electric switch associated with that length of shaft may operate both to stop the loom and also produce the signal for actuating the mechanism for drawing back that particular group of carriers.

Each withdrawing mechanism conveniently includes a bar for engagement with an upward projection on each yarn carrier in the respec tive group and mounted to move in an arc of a circle from a position defining the for wardmost position of the upward projections.

In its inoperative position, the bar is situated just forward of the upward projections so that the yarn carriers are free to move under the control of the jacquard in the usual way.

When the mechanism is actuated, the movement of the bar along its part-circular path brings it into engagement with the upward projections and then moves these rearwardly so as to withdraw the complete group of yarn carriers.

A construction in accordance with the inven tion will now be described by way of example, with reference to the accompanying drawing, which is a diagrammatic side view of the relevant parts of a loom.

A single yarn carrier is shown as 1 and, as can be seen, this operates in a horizontal plane as described in more detail in specifica tion No. 1,150,822. This yarn carrier is one of a large number of such carriers extending across the width of the loom, e.g. six groups of 184 carriers as. in the example quoted above. All the yarn carriers are controlled by jacquard mechanism an described in more detail in specification No. 1,150,822 and de tails of this are not illustrated other than a pair of straight-edges 2 to engage the jacquard controlled pegs (not shown) so as to move a selected one of the tuft yarns shown collec tively as 3 into register with the gripper asso ciated with each yarn carrier, part of which is shown as 4.Each gripper moves down wardly along an arcuate path indicated as 5 to withdraw a length of tuft yarn 3 which is then cut off by a knife (not shown). When a yarn carrier 1 has been moved to a selected position by means of the straight-edges 2, it is locked in that position by a locating bar 10 which engages one of a series of notches 11 at the rear end of the bar, according to the yarn selected. As so far described, the construction and operation are identical with that described in specification No. 1,150,822.

In addition, the loom includes detecting mechanism as described in the co-pending application No. 34350/77 (Serial No.

1,572923). For the purposes of the present specification, it is sufficient to say that this mechanism includes a member 15 which extends across the width of the loom and is caused to reciprocate as indicated by the arrow 16 in synchronism with the operation of the loom. The member carries a series of feelers 17, one for each yarn carrier, and as the member 15 starts to move towards the right, these are caused to project into the position shown under the control of a rocker shaft 18.

The timing is such that each feeler should engage the respective tuft yarn 3 while it is gripped by the gripper 4 so that the feeler is moved to a retracted position. The return of each feeler to the retracted position is sensed by a second rocker shaft 19, all as described in detail in the co-pending application just referred to. In the position illustrated, the gripper 4 has failed to withdraw a length of tuft yarn 3 and the detector mechanism has sensed this condition with the result that the loom is in the process of stopping and a signal is being transmitted which identifies the group of yarn carriers in which the missing yarn is situated.

In addition to the jacquard control already referred to, each yam carrier has an upward projection 25 which co-operates with an angle iron bar 26 which extends along the length of the group of yarn carriers. Referring again to the example previously quoted, there may be six such bars arranged end to end across a 4 metre width of loom, each bar controlling the 184 yarn ends previously mentioned. The bar 26 is carried by a pair of arms 27 spaced apart along the width of the loom and pivoted at their upper ends at 28 to part of the upper structure 29 of the loom. Each bar 26 is controlled by a pneumatic cylinder 32 suspended from the upper structure 29 by arms 33 and connected to one of the arms 27 by way of its connecting rod 34.

The full line position of the bar 26 and the arms 27 as shown in the drawing represents the inoperative position in which the bar 26 acts as a front stop for the yarn carriers 1 by engagement with the upward projections 25, of wbich the forwardmost position is shown in dotted lines as 25', the yarn carriers then projecting forwardly to the dotted line position shown as 1'. As mentioned above, there is a separate bar 26 together with its controlling cylinder 32 for each group of yarn carriers across the width of the loom.

Accordingly, when the detecting mechanism senses a missing tuft yarn as already described, the resultant signal- is applied to control the pneumatic cylinder 32 corresponding to the group of yarn carriers in which the missing yarn is detected. In order to allow the loom to come to rest at the correct stage in the operating cycle, a short delay is introduced electronically by means of a transducer and cam on the main drive shaft of the loom (not shown in the drawings) after which, the pneumatic cylinder 32 operates to retract its connecting rod 34 and move the bar 26 into the position shown in dotted lines 26', thus retracting the yarn carrier 1 to the position shown in full lines.

During the delay just referred to, the member 15 has moved back to the left to the position shown in dotted lines as 15' so that the forward ends of the feelers 17 are clearly visible to the operator who can immediately identify that which has not been returned to its withdrawn position and hence the carrier from which the tuft yarn is missing. The rear ends of the feelers 17 are also visible beyond the edge of a cover plate 20 seen more clearly in the drawings of the co-pending application No. 34350/77 (Serial No. 1572923).

By means of a time control (not shown in the drawings) the pneumatic cylinder 32 operates to return the bar 26 to the full line position. In a specific example, three seconds is found to be adequate for this purpose. Consequently, all the yarn carriers are free to move since at this stage of the cycle, the locating bar 10 is in a raised position as shown at 10' clear of any of the notches 11. Having identified the yarn carrier with the missing yarn, the operator is thus enabled to pull the carrier in question forwardly to the dotted line position 1', excess movement in this direction being prevented by the stop 25 and the bar 26 in its full line position. In this extended position, the carrier can be re-threaded without difficulty and the loom then restarted.

Since all the carriers of the group are kept within their normal working range, i.e. the faulty carrier withdrawn to the forward limit of this range and all the remainder retracted to the rearward limit of this range, there is no need to re-set any of the yarn carriers before re-starting operation since the jacquard mechanism resumes control in the normal way and re-sets the carriers to select the next required row of tuft yarns. In summary, therefore, the occurrence of a fault not only stops the loom, but also identifies the group of yarn carriers in which the fault has occurred by retracting these as just described. The retraction of the group of carriers enables the individual carrier to be identified without difficulty and enables it to be pulled forward for re-threading as just described.

WHAT WE CLAIM IS: 1. A carpet loom of the gripper Axminster type in which the yarn carriers are divided into a number of groups across the width of the loom, each group being provided with mechanism for withdrawing the carriers of the group into a retracted position, the loom also including a detecting mechanism for sensing a missing tuft yarn in a yarn carrier and operative, in the event of a missing tuft, to stop the loom and to provide a signal for selectively operating the mechanism for withdrawing that group of carriers which includes the carrier having the missing tuft yarn.

2. A carpet loom according to claim 1 and including a delay device between the detecting mechanism and each withdrawing mechanism.

3. A carpet loom according to claim 1 or claim 2 in which the detecting mechanism operates as described in the co-pending application No. 34350/77 (Serial No. 1572923).

4. A carpet loom according to any one of the preceding claims, in which each withdrawing mechanism includes a bar for engagement with an upward projection on each yarn carrier in the respective group and mounted to move in an arc of a circle from a position defining the forwardmost position of the upward projections.

5. A carpet loom according to claim 4, in which each bar is carried by a pair of pivoted arms and is operated by a pneumatic cylinder under the control of the signal from the detecting mechanism.

6. A carpet loom according to claim 1, in which the mechanism for drawing back each group of yarn carriers is substantially as described and as illustrated with reference to the accompanying drawing.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. member 15 has moved back to the left to the position shown in dotted lines as 15' so that the forward ends of the feelers 17 are clearly visible to the operator who can immediately identify that which has not been returned to its withdrawn position and hence the carrier from which the tuft yarn is missing. The rear ends of the feelers 17 are also visible beyond the edge of a cover plate 20 seen more clearly in the drawings of the co-pending application No. 34350/77 (Serial No. 1572923). By means of a time control (not shown in the drawings) the pneumatic cylinder 32 operates to return the bar 26 to the full line position. In a specific example, three seconds is found to be adequate for this purpose. Consequently, all the yarn carriers are free to move since at this stage of the cycle, the locating bar 10 is in a raised position as shown at 10' clear of any of the notches 11. Having identified the yarn carrier with the missing yarn, the operator is thus enabled to pull the carrier in question forwardly to the dotted line position 1', excess movement in this direction being prevented by the stop 25 and the bar 26 in its full line position. In this extended position, the carrier can be re-threaded without difficulty and the loom then restarted. Since all the carriers of the group are kept within their normal working range, i.e. the faulty carrier withdrawn to the forward limit of this range and all the remainder retracted to the rearward limit of this range, there is no need to re-set any of the yarn carriers before re-starting operation since the jacquard mechanism resumes control in the normal way and re-sets the carriers to select the next required row of tuft yarns. In summary, therefore, the occurrence of a fault not only stops the loom, but also identifies the group of yarn carriers in which the fault has occurred by retracting these as just described. The retraction of the group of carriers enables the individual carrier to be identified without difficulty and enables it to be pulled forward for re-threading as just described. WHAT WE CLAIM IS:

1. A carpet loom of the gripper Axminster type in which the yarn carriers are divided into a number of groups across the width of the loom, each group being provided with mechanism for withdrawing the carriers of the group into a retracted position, the loom also including a detecting mechanism for sensing a missing tuft yarn in a yarn carrier and operative, in the event of a missing tuft, to stop the loom and to provide a signal for selectively operating the mechanism for withdrawing that group of carriers which includes the carrier having the missing tuft yarn.

2. A carpet loom according to claim 1 and including a delay device between the detecting mechanism and each withdrawing mechanism.

3. A carpet loom according to claim 1 or claim 2 in which the detecting mechanism operates as described in the co-pending application No. 34350/77 (Serial No. 1572923).

4. A carpet loom according to any one of the preceding claims, in which each withdrawing mechanism includes a bar for engagement with an upward projection on each yarn carrier in the respective group and mounted to move in an arc of a circle from a position defining the forwardmost position of the upward projections.

5. A carpet loom according to claim 4, in which each bar is carried by a pair of pivoted arms and is operated by a pneumatic cylinder under the control of the signal from the detecting mechanism.

6. A carpet loom according to claim 1, in which the mechanism for drawing back each group of yarn carriers is substantially as described and as illustrated with reference to the accompanying drawing.