Method for separating a broken warp thread from the warp sheet, and a device which uses this method

Abstract

 Method for separating a broken warp thread from the warp, characterized in that it consists essentially of pressing an adhesive material (2) against the warp sheet (4), at the point of a broken warp thread (20) at least, and then withdrawing said adhesive material (2), with the result that the broken warp thread (20) is picked up by the adhesive material (2).

Description

[0001] This invention concerns a method for separating a broken warp thread from the warp sheet, and a device which uses this method. In particular, the method and the device according to the invention are intended for picking up a broken warp thread from the warp sheet near the warp beam.

[0002] It is known that when a warp break occurs, the corresponding warp thread, or in other words the broken section of thread, usually gets caught up in the neighbouring warp threads. Clearly therefore, in order to carry out a warp break repair automatically, the broken sections of thread have to be isolated from the warp sheet, so that they can be presented in a suitable manner to a tying-in device or similar.

[0003] In order to achieve this, the invention provides a method for separating a broken warp thread from the warp sheet, characterized in that it consists essentially of pressing against the warp sheet, at least at the point of the warp break at least, with an adhesive material and then withdrawing the same, with the result that the broken warp thread is picked up by said adhesive material.

[0004] According to the invention, for this purpose a device can be used consisting of firstly an adhesive material and secondly a drive mechanism for successively moving said adhesive material towards the warp, pressing it against the warp threads at the point of the broken warp thread and then withdrawing it from the warp threads.

[0005] In a preferred embodiment, the adhesive material consists of adhesive tape, which of course is pressed with the sticky side against the warp threads.

[0006] In a particular embodiment the drive mechanism also has a mechanism for feeding the adhesive tape from a supply roll to a takeup roll, such that with each new operating cycle an unused section of sticky tape is used, thus ensuring optimum adhesion of the adhesive material.

[0007] In order to explain the characteristics of the invention, the following preferred embodiment is described, by way of example only and without being limitative in any way, with reference to the accompanying drawings, where:

- fig. 1 shows a device according to the invention;

figs. 2 and 3 illustrate the steps of operation of the device shown in fig. 1;

fig. 4 shows schematically how the device according to the invention can be used for separating a broken warp thread on weaving machines.

[0008] As shown in fig. 1, the device 1 for carrying out the method according to the invention consists essentially of adhesive material 2 and a drive mechanism 3 for moving the adhesive material 2 towards the warp sheet or warp threads 4 from the warp beam 5, pressing against it and then withdrawing.

[0009] The adhesive material 2 consists in the embodiment shown of adhesive tape 6 which can be presented with its sticky side 7 towards the warp threads 4. In order to ensure optimum adhesion of the adhesive material 2 at all times, use is made of a supply roll 8 with adhesive tape, a takeup roll 9 in order to roll up the used tape 6, and a mechanism 10 to provide regular transport of the adhesive tape 6, as described in greater detail below.

[0010] The above-mentioned drive mechanism 3 for pressing the adhesive material 2 against the warp threads 4 and then withdrawing it consists in the embodiment shown essentially of a swivel arm 11 which can rotate about an axis 13 mounted on a frame 12, and a drive mechanism 14 to provide the rotation motion of the arm 11. Said drive mechanism 14 consists in the embodiment shown of e.g. a pneumatic cylinder mounted between the fixed frame 12 and the swivel arm 11. The free end 15 of the swivel arm 11 can be brought against the warp threads 4 as a result of the movement of the swivel arm 11. The free end 15 is provided with a spring-loaded roller 16 or suchlike over which the adhesive tape 6 is guided.

[0011] The above-mentioned mechanism 10 for ensuring the regular transport of the adhesive tape 6 has as its most important component a free-wheel mechanism 17, shown only schematically in the drawings, which is mounted on the axis 13 and which operates in conjunction with the swivel arm 11 and which is coupled to the takeup roll 9, such that - at least in the embodiment shown - when the swivel arm 11 turns clockwise the takeup roll 9 turns with it, while when the arm 11 turns counterclockwise takeup roll 9 does not turn with it. The supply roll 8 is mounted underneath the takeup roll 9 on a second axis 18 attached to the frame 12, so that it can also rotate.

[0012] Also mounted on the axis 18 there should be a device - not shown in the drawings - which exercises a certain braking force on the supply roll 8, so that the adhesive tape 6 always remains taut. The operation of the mechanism 10 is now described in detail below.

[0013] Since the adhesive tape 6 only has a narrow width, the device 1 should preferably be moved across the weaving width with the help of positioning device 19, so that it can be positioned at the point of the broken warp thread.

[0014] The operation of the device as described above can be simply deduced from figs. 1 to 3. By operating the drive mechanism 14, the free end 15 of the swivel arm 11 moves downwards until it comes in contact with the warp threads 4, as shown in fig. 2. The swivel arm 11 is then raised, so that the unbroken warp threads in the warp sheet 4 get loose from the adhesive tape, while the broken warp thread 20 is picked up by the adhesive material 2 and so separated from the warp sheet.

[0015] As a result of the operation of the free-wheel mechanism 17 the takeup roller 9 does not turn while the swivel arm 11 is moving downwards, so clearly the adhesive tape 6 will be transported over the spring-loaded roller 16 in the direction of arrow P, thus renewing the adhesive tape 6 at the end 15 of the swivel arm 11. While the swivel arm 11 is being raised, as shown in fig. 3, the takeup roll 9 will turn with the swivel arm 11, so that the position of the adhesive tape 6 with respect to the spring-loaded roller 16 remains unaltered, yet as a result of the distance A-B increasing the supply roll 8 will be unwound some more.

[0016] Clearly, the method according to the invention can also be used with other mechanisms than those described here, which may or may not make use of a swivel arm 11.

[0017] It should be noted that a particular aspect of the method according to the invention is that separating the broken warp thread should preferably be done at a small distance from the warp beam 5, since at this point the warp threads all lie in the same plane, thus giving a high degree of reliability that the broken warp thread will be picked up by the adhesive material 2.

[0018] Along the device 1, in particular along the adhesive tape 6, shielding - not shown in the drawings - may be fitted in order to prevent weaving dust sticking to it.

[0019] In order to further explain the invention, an application is now described, in particular for separating a broken warp thread from the warp sheet on a weaving machine.

[0020] Besides the device 1 according to the invention, in fig. 4 the warp beam 5, the warp threads 4 and a number of other known components of a weaving machine are shown schematically, such as the backrest roller 21, a warp stop motion 22 with several rows of drop wires 23, the shed 24, the harnesses 25, the reed 26 and the cloth beam 27.

[0021] In the case where a break 28 occurs in the warp threads 4, for example between the backrest roller 21 and the warp stop motion 22, as shown in fig. 4, the two thread ends 29 and 30 thus formed, i.e. the thread end attached to the warp beam 5 and the thread end extending from the warp stop motion 22 respectively, are first located and gripped. Locating the thread ends 29 and 30, i.e. locating the position of the break 28 with respect to the weaving width, can be done by a known device, for locating the drop wire which has fallen as a result of the break 28, for example as described in Dutch patent application No. 8600732 of the present applicant.

[0022] Once the thread end 29 has been located, the device 1 according to the invention is positioned at the corresponding point and is then operated, with the result that the thread end 29 is separated.

[0023] Locating and gripping the other thread end 30 is done by e.g. a device 31, as described in Belgian patent application No. 8700254 of the present applicant, with the result that the thread end 30 is gripped immediately before the warp stop motion 22, for example by a suction nozzle 32.

[0024] The present invention is not limited to the embodiments described by way of example and shown in the drawings; on the contrary, such a method and device for separating a broken warp thread from the warp sheet on weaving machines can be made in different variants while still remaining within the scope of the invention.

Claims

1. Method for separating a broken warp thread from the warp sheet, characterized in that it consists essentially of pressing an adhesive material (2) against the warp sheet (4), at least at the point of a broken warp thread (20) and then withdrawing said adhesive material (2), with the result that the broken warp thread (20) is picked up by the adhesive material (2).

2. Method as in claim 1, characterized in that the adhesive material (2) is pressed against the warp sheet (4) in the immediate vicinity of the warp beam (5).

3. Device which uses the method as in claim 1 or 2, characterized in that it consists essentially of an adhesive material (2) and a drive mechanism (3) for pressing the adhesive material (2) against the warp sheet (4) and withdrawing it from the warp sheet (4) respectively.

4. Device as in claim 3, characterized in that the adhesive material (2) consists of adhesive tape (6) which is presented with its sticky side (7) towards the warp sheet (4).

5. Device as in claim 3 or 4, characterized in that the drive mechanism (3) which provides the movement of the adhesive material (2) consists essentially of a swivel arm (11) whose free end (15) can make contact with the warp sheet (4).

6. Device as in claim 5, characterized in that movement of the swivel arm (11) is driven by a cylinder (14).

7. Device as in any of the claims 3 to 6, characterized in that the device is provided with respectively a supply roll (8) with adhesive tape and a takeup roll (9) on which the used adhesive tape (6) is wound up.

8. Device as in claim 7, characterized in that it is provided with a mechanism (10) which ensures the regular movement of the adhesive tape (6), and winding it off the supply roll (8) and onto the takeup roll (9) respectively.

9. Device as in claim 7 or 8, characterized in that the takeup roll (9) and the swivel arm (11) are mounted on the same axis (13), while the supply roll (8) is mounted underneath the takeup roll (9), such that the adhesive tape (6) is guided over the free end (15) of the swivel arm (11).

10. Device as in claim 9, characterized in that the mechanism (10) for ensuring the regular movement of the adhesive tape (6) consists essentially of a free-wheel mechanism (17), such that when the swivel arm (11) is moved towards the warp (4) the takeup roll (9) does not turn with the swivel arm (11), while when the swivel arm (11) is withdrawn the takeup roll (9) does turn with the swivel arm (11).

Drawing