US20080178959A1

US20080178959A1 - Catching apparatus and method for a rapier weaving machine

Info

Publication number: US20080178959A1
Application number: US11/986,628
Authority: US
Inventors: Marcel Christe
Original assignee: Sultex AG
Current assignee: Itema Switzerland Ltd
Priority date: 2006-11-29
Filing date: 2007-11-21
Publication date: 2008-07-31
Also published as: DE502007002850D1; CN101230515A; JP2008138351A

Abstract

A catching device (1) for holding an inserted weft thread in a rapier weaving machine having at least one rapier (6), which is movable along a rapier track (6 a), includes a holding channel (5) which can be mounted in a stationary manner on the rapier weaving machine in order to take up a thread end of the inserted weft thread (9) and to hold it. In addition, the catching device includes a deflection nozzle (3) which can be mounted in stationary manner on the rapier weaving machine in order to deflect the thread end of the inserted weft thread to the holding channel (5).

Description

The invention relates to a catching device and to a method for the holding of an inserted weft thread in a rapier weaving machine in accordance with the preamble of claims 1 and 5 and also to a rapier weaving machine having such a catching device or equipped to carry out such a method.
In customary rapier weaving machines the weft thread is inserted into a shed by means of a bringer rapier secured to a rapier rod or to a flexible band and is taken over at a transfer position in the middle part of the shed by a taker rapier and conveyed further. The bringer rapier has the task of reliably taking up the presented weft thread, of inserting the same into the shed and guiding it precisely to the taker rapier. The taker rapier has the task of conveying the weft thread further until it has reached a release position outside of the shed. Each of the rapiers includes a rapier head with a thread clamp in order to fixedly clamp the weft thread during the weft insertion. In the release position outside of the shed the thread clamp of the taker rapier is opened and the thread end which is fixedly clamped therein is released. In order that the weft thread remains stretched a catch selvage is normally provided in rapier weaving machines, which is closed directly after the weft insertion and still before the shed, as well as a suction nozzle or suction channel which takes up the thread end and holds it firmly.
A suction device for rapier weaving machines is disclosed in the document JP 09-059848 A which surrounds the weft thread at the arrival side between the release position and the shed on three or four sides and in which a suction groove is formed which is connected to a suction system. In this way it is possible to suck in the released thread end from a plurality of directions and hold it firmly in the suction groove.
With coarse weft yarns the suction flow of customary suction devices and nozzles is not always however sufficient in order to firmly hold the thread end during the beat up of the reed, because the thread end is picked up not until after the beat up of the reed by the suction device or nozzle and the beat up movement of the reed generates an air flow which draws the thread end behind the reed. In this arrangement, the danger exists that the thread end is woven in behind the reed and thus the shed can no longer be opened in the edge region. During the next weft insertion the warp threads are then torn in the affected region by the taker rapier.
The object of the invention is to make available a catching device and a method for the holding of an inserted weft thread in a rapier weaving machine, as well as a rapier weaving machine having such a catching device or equipped to carry out such a method, by means of which even coarse weft yarns can be reliably held after the insertion.
This object is satisfied in accordance with the invention by the catching device defined in claim 1, by the method defined in claim 6 and by the rapier weaving machine defined in claim 10.
The catching device in accordance with the invention for the holding of an inserted weft thread in a rapier weaving machine having at least one rapier which is movable along a rapier track includes a holding channel which can be mounted in stationary manner on the rapier weaving machine in order to take up a thread end of the inserted weft thread and to hold it. In addition the catching device includes a deflection nozzle which can be mounted in stationary manner on the rapier weaving machine, for example a deflection nozzle with a cyclically pulsed blowing flow, in order to deflect the thread end of the inserted weft thread to the holding channel. In an advantageous variant the holding channel is designed for the connection of a suction line.
In an advantageous embodiment the holding channel and the deflection nozzle can be installed in the region of the rapier track, for example on opposite sides of the rapier track. I.e. the holding channel and the deflection nozzle are so designed and/or the catching device is provided with fastener elements in such a way that the holding channel and the deflection nozzle can be installed in the region of the rapier track. In a further advantageous embodiment the deflection nozzle can be so installed that its blowing flow is directed transverse to the rapier track. The deflection nozzle and the holding channel can be advantageously mounted in such a way that the blowing flow of the deflection nozzle is partly or fully taken up by the holding channel.
In the method of the invention for the holding of an inserted weft thread in a rapier weaving machine having a shed and at least one rapier, which inserts the weft thread along a rapier track into the shed, the inserted weft thread is released by the rapier and a thread end of the inserted weft thread is taken up and held by a holding channel which is arranged in stationary manner on the rapier weaving machine. In addition, the thread end of the inserted weft thread is deflected to the holding channel by means of a deflection nozzle which is arranged in stationary manner on the rapier weaving machine. In an advantageous variant the thread end of the inserted weft thread is held in the holding channel by means of a blowing flow and/or suction flow.
In an advantageous embodiment of the method a blowing flow is generated transverse to the rapier track by means of the deflection nozzle. In a further advantageous embodiment of the method the thread end of the inserted weft thread is blown into the holding channel and/or held therein by means of a blowing flow of the deflection nozzle.
Furthermore, the invention includes a rapier weaving machine having a catching device in accordance with one of the above described embodiments or equipped to carry out a method in accordance with one of the above described embodiments.
The catching device, the method and the rapier weaving machine in accordance with the present invention have the advantage that even with coarser weft yarns the thread ends can no longer pass behind the reed. Thus, a better fabric quality can be achieved, especially with coarser weft yarns, than is possible on rapier weaving machines with customary catching devices. Moreover, in comparison to rapier weaving machines with customary catching devices, the downtimes of the rapier weaving machines caused by break-downs can also be reduced. It is furthermore advantageous, thanks to the above-described catching device and the above-described method, that the manufacturing costs and the energy consumption and servicing costs can be reduced in comparison to customary catching devices for rapier weaving machines, because the suction fan and the filter unit provided between the holding channel and the suction fan can be made smaller or can be omitted altogether, because the generation of the directed blowing flow requires less energy than the generation of a broadly fanned out suction flow in the region of the rapier track. At the same time the servicing costs for the filter unit can be respectively reduced or fully avoided.
The above description of embodiments merely serves as an example. Further advantageous embodiments can be seen from the dependent claims and the drawing. Moreover, in the context of the present invention, individual features of the described illustrated embodiments and variants can be combined with one another in order to form new embodiments.

The invention will be described in the following in more detail with reference to the embodiment and to the drawing. There are shown:

FIG. 1 an embodiment of a catching device in accordance with the present invention in a rapier weaving machine from above and

FIG. 2 a perspective view of the embodiment of FIG. 1.

The FIGS. 1 and 2 show an embodiment of a catching device in accordance with the present invention in a rapier weaving machine from above and in perspective view, respectively. The rapier weaving machine includes at least one rapier 6 which can, for example, as shown in FIG. 1 be designed as a taker rapier. The rapier shown in FIG. 1 is movable to and fro in the direction 6 a′ and on the rapier track 6 a in order to insert a weft thread 9 into a shed which is formed by warp threads 10, 10.1, 10.2. For the guidance of the rapier 6 a rapier guide 2 can be provided. The rapier can, as shown in FIG. 1, be provided with a thread clamp in order to fixedly clamp the weft thread during the weft insertion. FIG. 1 shows a weft thread after the weft insertion, with the thread clamp being opened in order to release the inserted weft thread. The catching device 1 that is shown includes a holding channel 5 which is arranged in stationary manner on the rapier weaving machine. It can, for example, be secured by means of a fastener element 7.2 to the rapier guide 2 in order to take up and to hold the thread end of the inserted weft thread 9. In addition the catching device that is shown includes a catching nozzle 3 which is arranged in stationary manner on the rapier weaving machine. It can, for example, be secured by means of fastener elements 7.1, 7.1′, 7.1″ to the rapier guide 2. The catching nozzle 3 is advantageously connected to a line 3 a in order to supply a blowing fluid. A blowing flow can be produced by means of the deflection nozzle 3 in order to deflect the thread end of the inserted weft thread towards the holding channel 5. If required, the blowing flow can be pulsed cyclically.
In an advantageous embodiment the holding channel 5 and the deflection nozzle 3 are installed, as shown in FIGS. 1 and 2 in the region of the rapier track 6 a, for example on opposite sides of the rapier track. In a further advantageous embodiment a blowing flow 4 transverse to the rapier track 6 a can be generated by means of the deflection nozzle 3.
In an advantageous embodiment the thread end of the inserted weft thread is blown by means of the deflection nozzle 3 into an opening 5 a of the holding channel 5, for example in that the deflection nozzle and the holding channel are so mounted that the blowing flow of the deflection nozzle is directed towards the holding channel and/or can be partly or wholly taken up by the holding channel. In a further advantageous variant the holding channel 5 is designed for the connection of a suction line so that the thread end of the inserted weft thread can be conveyed by means of a blowing flow and/or suction flow into the opening 5 a of the holding channel 5. Depending on the embodiment, the inserted weft thread can subsequently be held in the holding channel 5 by means of the blowing flow and/or suction flow.
The rapier weaving machine can, as shown in FIGS. 1 and 2 be equipped with a reed 8 in order to beat up the inserted weft thread 9 at a beat up edge 12. The thread end of the inserted weft thread is thereby deflected, as described above, by the blowing flow 4 of the deflection nozzle 3, to the holding channel 5 so that the thread end cannot pass behind the reed during the beat up movement thereof. Thanks to this measure fabric faults are avoided which can arise through thread ends woven in behind the reed. In an advantageous variant the thread ends of the weft threads 9′, 9″, 9′″ which were woven in earlier remain in the holding channel 5 until they are drawn out of the holding channel by the advance of the fabric 11 produced by the weaving process. The thread ends which are drawn out of the holding channel are at this point in time so far removed from the reed 8 that no danger any longer exists that they will be woven in.
An embodiment of the method of the invention for the holding of an inserted weft thread in a rapier weaving machine will be described in the following with reference to FIGS. 1 and 2. In the embodiment the rapier weaving machine includes at least one rapier 6 which is moved along a rapier track 6 a for the insertion of the weft thread. The inserted weft thread 9 is then released by the rapier and the thread end of the inserted weft thread is taken up and held by a holding channel arranged in stationary manner on the rapier weaving machine. In addition the thread end of the inserted weft thread is deflected towards the holding channel 5 by means of a deflection nozzle 3 which is arranged in stationary manner on the rapier weaving machine.
In an advantageous embodiment of the method a blowing flow 4 trans-verse to the rapier track 6 a is generated by means of the deflection nozzle 3. In a further advantageous embodiment of the method the thread end of the inserted weft thread 9 is blown by means of the blowing flow 4 of the deflection nozzle 3 into the holding channel 5. In an advantageous variant the thread end of the inserted weft thread 9 is held in the holding channel 5 by means of a blowing flow and/or suction flow.
Furthermore, the invention includes a rapier weaving machine having a catching device in accordance with one of the above-described embodiments and/or equipped to carry out a method in accordance with the above description.
The catching device and the method in accordance with the above description are suitable for the holding of fine and coarse weft yarns in rapier weaving machines. Thanks to the use of a deflection nozzle the energy cost and the cost of servicing can be reduced relative to customary catching devices for rapier weaving machines which are simply provided with a suction channel.

Claims

1. A catching device for holding an inserted weft thread in a rapier weaving machine having at least one rapier (6) which is movable along a rapier track (6 a), said catching device (1) including a holding channel (5) which can be mounted in a stationary manner on the rapier weaving machine in order to take up a thread end of the inserted weft thread (9) and to hold it, characterized in that the catching device additionally includes a deflection nozzle (3) which can be mounted in stationary manner on the rapier weaving machine, in particular a deflection nozzle having a cyclically pulsed blowing flow in order to deflect the thread end of the inserted weft thread to the holding channel (5).

2. A catching device in accordance with claim 1, wherein the holding channel (5) is designed for connection to a suction line.

3. A catching device in accordance with claim 1, including in addition fastener elements (7.1, 7.1′, 7.1″, 7.2) in order to mount the holding channel (5) and the deflection nozzle (3) in the region of the rapier track (6 a) in particular on opposite sides of the rapier track.

4. A catching device in accordance with claim 1, wherein the deflection nozzle (3) can be mounted so that a blowing flow (4) of the same is directed transverse to the rapier track (6 a).

5. A catching device in accordance with claim 1, wherein the deflection nozzle (3) and the holding channel (5) can be mounted in such a way that the blowing flow (4) of the deflection nozzle is partly or fully taken up by the holding channel.

6. A method for the holding of an inserted weft thread in a rapier weaving machine having a shed and at least one rapier (6) which inserts the weft thread along a rapier track (6 a) into the shed, in which method the inserted weft thread (9) is released by the rapier and a thread end of the inserted weft thread is taken up and held by a holding channel arranged in a stationary manner on the rapier weaving machine, characterized in channel arranged in a stationary manner on the rapier weaving machine, characterized in that the thread end of the inserted weft thread is deflected to the holding channel (5) by means of a deflection nozzle (3) which is arranged in stationary manner on the rapier weaving machine.

7. A method in accordance with claim 6, in which a blowing flow (4) transverse to the rapier track (6 a) is produced by means of the deflection nozzle (3).

8. A method in accordance with claim 6, in which the thread end of the inserted weft thread (9) is blown by means of a blowing flow (4) of the deflection nozzle (3) into the holding channel (5).

9. A method in accordance with claim 6, in which the thread end of the inserted weft thread (9) is held by means of a blowing flow and/or suction flow in the holding channel (5).

10. A rapier weaving machine comprising a catching device in accordance with claim 1.

11. A rapier weaving machine adapted to carry out a method in accordance with claim 5.