GB1572923A

GB1572923A - Carpet looms

Info

Publication number: GB1572923A
Application number: GB3435077A
Authority: GB
Original assignee: Brintons Ltd
Current assignee: Brintons Carpets Ltd
Priority date: 1978-05-25
Filing date: 1978-05-25
Publication date: 1980-08-06

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: - The invention relates to carpet looms of the gripper Axminster type and is particularly concerned with mechanism for detecting a missing tuft yarn, of the same general kind as described and claimed in our prior patent specification no: 1,089,844. In one form of the mechanism described in this earlier specification, a separate feeler is provided for each tuft yarn and the feelers are mounted to slide in a member extending across the loom.

During each cycle of the operation of the loom this member, with the feelers projecting from it, is caused to move in a direction transverse to the length of the tuft yarns so that the projecting feelers are brought into engagement with the respective yams. This causes the feelers to slide back into the member, but if a yarn is missing, the correspond- ing feeler remains in the projecting position, thus bringing about the operation of a device for stopping the loom.

As described in more detail, the feelers are caused to project in advance of the transverse movement of the member by means of a rocker shaft formed with a longitudinally extending recess, one edge of which engages the feelers and causes them to project as a result of rocking movement of the shaft in one direction and the other of which on the return movement of the shaft detects any feeler remaining in the projecting position as a result of the absence of its tuft yarn.

While mechanism as described in this prior specification has been found to be entirely satisfactory in practical operation, it has since been appreciated that the fact that a single member, i.e. the rocker shaft just referred to, performs the double function of causing the feelers to project and of detecting the failure of any feeler to return to the withdrawn position causes difficulties of adjustment. In other words a setting which gives optimum control of the movement of the feelers may not be ideal for detecting their subsequent positions.

This is particularly the case when the mechanism is used on a loom as described and claimed in our prior patent specification no: 1,075,082 in which the yarn carriers operate in a substantially horizontal plane and the free ends of the tuft yarns extend downwardly. This means that the individual detectors extend and slide in a horizontal direction and, as a consequence, it is possible to dispense with the springs shown as 19 in specification no: 1,089,844. The freedom of movement of the feelers renders their control more critical.

According to the present invention, a detector mechanism of this same general kind, that is to say comprising a separate feeler corresponding to each tuft yarn and mounred to slide in a member which extends across the width of the loom and has mechanism for causing it to reciprocate in a transverse direction in step with the operation of the loom whereby each feeler engages its respective tuft yarn at the point where it is held taut by the corresponding gripper, has within the reciprocatory member two separate rocker shafts, the first for causing the feelers to project from the member in advance of their transverse movement towards the tuft yarns and permitting return movement of the feelers on engagement with the tuft yarns and the second for detecting any feeler not so returned and for operating a device to stop the loom.By including two separate rocker shafts in this way and thus separating the functions of causing the feelers to project and of detecting any feeler not returned to its withdrawn position, it is found that the operation is simplified, primarily because the two rocker shafts can be adjusted quite independently of one another so as to provide optimum results in both the control of the movement of the feelers and in the detection of their subsequent positions.

The first rocker shaft may be somewhat similar to that described in the earlier speci fiction in that it has a cut-away portion defining an edge for engagement with a shoulder on each feeler, but the shape of the cut-away portion is such that there is no cofresponding second edge capable of engaging the feelers, so that even if one or mare of the feelers remains in the projecting position, the return movement of this rocker shaft is not impeded. In such a construction, the second rocker shaft needs to be spaced from the first in a direction parallel to the length of the feelers and to have a projection which engages the body of any feeler not returned to the withdrawn position, thus stopping movement of the second rocker shaft to operate the stopping device for the loom.

The shoulder on each feeler which is engaged by the first rocker shaft is conveniently defined by the edge of a recess in each feeler into which the projection on the second rocker shaft enters when the feeler is in the withdrawn position. If one or more feelers have not returned to the withdrawn position, the respectiv recess or recesses are not in register with the projection which then comes into engagement with the body of the feeler or feelers to operate the stopping device. Engagement of the projection with one or more feelers impedes the rocking movement of the second rocker shaft and the drive to this shaft needs to be made to yield accordingly.

The yielding of the drive can be used to operate the stopping device, for example in a manner similar to that described in the prior specification, but preferably engagement of the projection on the second rocker shaft with the body of a feeler completes an electric circuit to operate the stopping device. If electrical operation is utilised, the projection need not regisrer with recesses in the feelers. Instead, each feeler may include a short length of insulating material with which the projection engages if all the feelers have returned cor rectify to the withdrawn position. On the other hand, if any one or more feelers has not returned to the withdrawn position, the projection then engages the conducting body of the feeler or feelers to establish the electrical circuit referred to.

when a tuft yarn is missing and the detector mechanism operates to stop the loom, it is then a question of identifying the position of the missing yarn, which is by no means simple in view of the hundreds of yarns involved. Electrical operation is particularly advantageous in this connection and the second rocker shaft is preferably divided into a number of lengths which are electrically insulated from one another and are connected in parallel circuits to control the stopping device and also to control individual indicators.

AccordWy, engagement of the projection on the rocker shaft with a feeler completes the electric circuit associated with the respective length of rocker shaft and thus identifies the length containing the feeler not returned by engagement with the respective tuft yarn.

Parts of a loom in accordance with the present invention will now be described in more detail, by way of example, with reference to the accompanying drawings, in which Figures 1 and 2 are corresponding sectional views of detector mechanism shown in alternative position in relation to a yarn carrier of the loom; Figure 3 is a general view to a reduced scale showing driving connections for the different parts of the detector mechanism; and Figure 4 is a plan view showing details of the construction of rocker shafts seen in Figures 1 and 2.

The detector mechanism shown in Figures 1 and 2 is illustrated in conjunction with a loom as described in our prior patent specification no: 1,075,082 in which the yarn carriers operate in a substantially horizontal plane and the free ends of the tuft yarns extend downwardly. A single such yarn carrier is shown as 1 in Figures 1 and 2 and is the only part of the loom which is relevant in the present connection, other details of the loom being substantially as described in the earlier specification.Ends of tuft yarns 2 pro- ject vertically downwardly from the carrier 1 and horizontal movement of the carrier 1 under the control of jacquard mechanism brings a selected yarn end shown as 2A into register with a gripper 3 which withdraws the yarn as shown in Figure 1, after which the withdrawn length of yarn is cut in the usual way and then transferred by the gripper 3 to the body of the carpet being woven.

In order to detect a missing tuft yarn or the failure of a gripper 3 to withdraw a length of tuft yarn., detector mechanism is included of which the main component is a member 10 seen in cross-section in Figures 1 and 2 which extends across the width of the loom and carries a number of feelers 11 corresponding to the yarn carriers 1, i.e. there is one feeler 11 for each yarn carrier 1. The basic function of the feelers 11 is exactly the same as described in the earlier specification 1,089,844, but since the loom has horizontally extending yarn carriers, the feelers 11 also extend horizontally and thus do not require any spring control as illustrated in the earlier specification. The added freedom of movement of the feelers 11 renders their control correspondingly more critical. The member 10 is caused to reciprocate in a generally horizontal direction as indicated by the arrow 12 in Figures 1 and 2, moving to the right as the gripper 3 moves downwardly to withdraw a length of tuft yarn as seen in Figure 1. Prior to this movement to the right, each feeler 11 is moved to an extended position as seen in Figure 2 by means of a first rocker shaft 15 located within the member 10. The shaft 15 has a cut away portion defining an edge 16 for engagement with a shoulder 17 on each feeler and defined by the side of a recess 18. Clockwise rotation of the shaft 15 brings the edge 16 into engagement with the shoulder 17 of each feeler, causing it to project to the right in the position of Figure 2 as the member 10 also moves to the right.Provided the tuft yarn 2A has been correctly gripped and withdrawn by the gripper 3, it is engaged by the respective feeler 11 and continued movement to the right of the member 10 causes the feeler 11 to be returned to the withdrawn position as seen in Figure 1. The return movement of the shaft 15 in the anti-clockwise direction is synchrnnised with the return movement of the feelers 11 so that the edge 16 remains in contact with the shoulders 17 during this return movement and prevents this being excessively rapid.

A second rocker shaft 22 extends parallel with the shaft 15 and is driven in synchronism with it. The shaft carries an electrically conducting projection 23 which, when all the tuft yarns are present and all the feelers 11 are returned to the position of Figure 1 by engagement with their respective tuft yarns, enters the recess 18 as shown in Figure 1 which thus permits free rocking movement of the shaft 22. As long as no tuft yarns are missing, the two shafts 15 and 22 rock in synchronism with one another, the projecoon 23 entering the recesses 18 and moving away again prior to the feelers 11 being moved to the extended position of Figure 2.If a tuft yarn is missing or is not withdrawn by the gripper 3, as illustrated in Figure 2, the cooreoponding feeler 11 is not returned to the withdrawn position and the projection 23, instead of entering the recess 18, comes into engagement with the body of the feeler 11 as shown at 24 in Figure 2. This not only stops rotation of the shaft 22, but it establishes an electrical circuit between the feeler 11 and the shaft 22 and hence via a stud 26 and a spring 27 to an electrical terminal 28. Completion of this electrical circuit operates both to stop the loom as a whole and also to identify the region in which the missing tuft yarn is situated, as will now be described in more detail.

In the plan view of Figure 4, it will be seen that the shafts 15 and 22 are formed of separate lengths connected together by dogs 30 and 31 respectively. In the case of the shaft 15, this is merely a matter of convenience and the dogs are of steel, but in the case of the shaft 22, by using insulated dogs 31, the shaft is divided up into a number of lengths which are electrically insulated from one another and each of which has an associated projection 23 and is provided with an individual stud 26 and spring 27 connected in a separate, parallel circuit Accordingly, when a tuft yarn is missing, only one of these parallel circuits will be complteed, the insulating dogs 31 preventing the completion of the other parallel circuits. The two shafts 15 and 22 have end bearings 19 and intermediate bearings 20 (also seen in Figures 1 and 2).

Each of the parallel circuits operates to stop the loom as a whole, but in addition it operates an indicator (not shown in the drawings) which identifies the circuit in question and hence the respective length of shaft 22 and hence the group of feelers 11 in which the undisplaced feeler is included. This greatly assists in location of the missing yarn since only the feelers in the group in question need be inspected and that which projects beyond the others may readily be identiified. The completion of the electrical circuit may also fulfil a second function to facilitate re-threading of the yarn carrier as described in more detail in the copending application number 34351/77 (Serial No. 1 572 924).

Figure 3 of the drawings illustrates the mechanical drives for rocking the shafts 15 and 22 and also for reciprocating the member 10 as a whole. The member 10 is mounted at the lower end of supporting arms 35 which swing about a pivotal axis 36 under the control of a link 37 connected just above the member 10. The opposite end of the link 37 is connected at 38 to an arm 39 pivoted at 40 and carrying a cam follower 41 cooperating with a cam surface 42. The cam is driven from the main drive to the loom so that the reciprocating movement of the member 10 are synchronised with the other operations described and, in particular, serve to move the projecting feelers 11 into engagement with the tuft yarns as they are drawn out by the grippers 3.

The shafts 15 and 22 are rocked by means of cams on the same shaft, the shaft 15 having at its end an arm 45 connected by a link 46 to a further arm 47 which constitutes one arm of a bell crank, the other arm 48 of which carries a cam follower 49 co-operat ing with a cam surface 50. The arm 47 is acted on by a tension spring 51 which holds the follower 49 firmly in contact with the cam surface 50.

The rocker shaft 22 has a somewhat similar drive comprising an arm 55 connected to the end of the shaft and in its turn connected by a link 56 to an arm 57 pivoted at 58 and forming one arm of a bell crank of which the other arm 59 carries a follower 60 co operating with a cam surface 61 against which ir is pressed by means of a tension spring 62 acting on the arm 57. The con nection between the link 56 and the arm 57 is by way of a small bell crank having arms 64 and 65 which is pivoted to the end of the arm 57 at 66. The arm 65 is also connected via a spring-loaded link 67 to a point 68 on the arm 57. Under conditions of normal operation, the link 67 holds the bell crank 64, 65 in a fixed angular position in relation to the arm 57 so that the effect is the same as if the link 56 were connected directly to the end of the arm 57.When a missing tuft yarn is detected, however, and rocking movement of the shaft 22 is impeded, the driving connection as far as the upper end of the link 56 remains stationary, but the arm 57 continues to be driven by the cam surface 61 and the spring loaded link 67 yields to allow the bell crank 64, 65 to absorb the lost motion.

WHAT WE CLAIM IS: 1. A carpet loom of the gripper Axminster type and including detector mechanism comprising a separate feeler corresponding to each tuft yarn and mounted to slide in a member which extends across the width of the loom and has mechanism for causing it to reciproi cate in a transverse direction in step with the operation of the loom whereby each feeler engages its respective tuft yarn at the point where it is held taut by the corresponding gripper, the detector mechanism also comprising within the reciprocatory member a first rocker shaft for causing the feelers to project from the member in advance of their transverse movement towards the tuft yarns, and permitting return movement of the feelers on engagement with the tuft yarns and a second rocker shaft-for detecting any feeler not so returned and for operating a device to stop tiie loom.

2. A carpet loom according to claim 1, in which the first rocker shaft has a cut-away potion defining an edge for engagement with a shoulder on each feeler and the second rocker shaft is spaced from the first in a direction parallel to the length of the feelers and has a projection which engages the body of any feeler not returned to the withdrawn position and thus stops movement of the second rocker shaft to operate the stopping device for the loom.

3. A carpet loom according to claim 2 in which the shoulder on each feeler is defined by the edge of a recess into which the projection enters when the feeler is in the withdrawn position.

4. A carpet loom according to claim 2 or claim 3 in which the rerun movement of the first rocker shaft is synchronised with that of the feelers so that engagement between the edge on the shaft and the shoulders on teh feelers controls the movement of the latter.

5. A carpet loom according to any one of claims 2 to 4, in which engagement of the projection on the second rocker shaft completes an electric circuit to operate the stopping device.

6. A carpet loom according to claim 5, in which the second rocker shaft and the associated projection are divided into a number of lengths which are electrically insulated from one another and are connected in parallel circuits to control the stopping device and also to control individual indicators whereby engagement of the projection with a feeler completes the electric circuit associated with the respective length of rocker shaft and thus identifies the length containing the feeler not returned by engagement with the respective tuft yarn.

7. A carpet loom according to any one of the preceding claims in which the reciprocatory member is mounted to swing about a pivot point under the control of a camoperated linkage.

8. A carpet loom according to any one of the preceding claims in which the two rocker shafts are driven by cam-operated linkages, that for the second rocker shaft including a spring-loaded connection which yields when movement of the rocker shaft is impeded.

9. A carpet loom fitted with a detector mechanism which is substantially as described and as illustrated with reference to the accompanying drawings.

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. the arm 57. Under conditions of normal operation, the link 67 holds the bell crank 64, 65 in a fixed angular position in relation to the arm 57 so that the effect is the same as if the link 56 were connected directly to the end of the arm 57. When a missing tuft yarn is detected, however, and rocking movement of the shaft 22 is impeded, the driving connection as far as the upper end of the link 56 remains stationary, but the arm 57 continues to be driven by the cam surface 61 and the spring loaded link 67 yields to allow the bell crank 64, 65 to absorb the lost motion. WHAT WE CLAIM IS:

1. A carpet loom of the gripper Axminster type and including detector mechanism comprising a separate feeler corresponding to each tuft yarn and mounted to slide in a member which extends across the width of the loom and has mechanism for causing it to reciproi cate in a transverse direction in step with the operation of the loom whereby each feeler engages its respective tuft yarn at the point where it is held taut by the corresponding gripper, the detector mechanism also comprising within the reciprocatory member a first rocker shaft for causing the feelers to project from the member in advance of their transverse movement towards the tuft yarns, and permitting return movement of the feelers on engagement with the tuft yarns and a second rocker shaft-for detecting any feeler not so returned and for operating a device to stop tiie loom.