EP0155432A1 - Loom - Google Patents

Abstract

Between the stationary supply package (4) and the yarn transfer point (20) of the projectile weaving machine there is disposed a yarn accelerating nozzle (14) and a yarn braking nozzle (13) with or without a yarn transfer nozzle (18). The accelerator nozzle (14) can receive an air pulse at the start of insertion, which, in particular in the case of a high number of picks for minute and rapid acceleration of the weft thread (1), ensures an additional entraining effect and consequently a lower stress on the yarn. Accordingly, towards the end of insertion, the retarder or brake nozzle (13) can receive an air pulse to initiate a particularly gentle braking phase. This again serves to reduce the stress on the weft thread. The compressed air fed device for influencing the weft thread movement during insertion is suitable in particular for high numbers of picks per minute, of the order of 400 min<-><1> or more, and also for large weaving widths with a relatively high inertial force of the weft thread to be inserted. <IMAGE>

Description

The invention relates to a weaving machine with a weft supply bobbin remaining outside the shed and an entry element which penetrates the shed during the weft insertion, e.g. Projectile.

In a previous machine of this type (DE-PS 836 926 = US-PS 2 589 429 / T. 129), the weft thread is drawn in exclusively by the tensile force of the projectile and is drawn off from a thread supply (supply spool). At the end of the entry, the projectile and the trailing thread are simultaneously braked by friction brakes and brought to a standstill.

If the weaving machine is to be operated at high speed and, if necessary, sensitive yarns are to be processed, the disadvantage can arise that the weft yarn must be subjected to particularly high acceleration and thus thread stress at the start of entry. Conversely, the yarn at Entrysenae must be braked strongly and therefore subjected to special stresses. At the start of entry, the thread tip can be torn out of the clamp of the entry element under the suddenly occurring high tensile force (thread loser), at the end of the entry, the thread can be crushed in the thread brake under the influence of the relatively high mass force that quickly sets in during braking. In both cases, the web operation can be disrupted.

The invention has for its object to provide a particularly improved machine in this regard.

The invention consists in that a compressed-air-fed device for influencing the weft movement during the insertion is provided between the supply spool and a point of transfer of the weft thread to the insertion member.

This makes it e.g. possible to influence the weft thread during the entry so that it experiences a particularly gentle, additional acceleration at the beginning of the entry. As a result, the strong thread stress that arises at the start of the entry can be reduced or avoided.

At the end of the entry, the thread can be slowed down in a particularly gentle manner. For this purpose, the device for influencing the weft movement only has to be fed and controlled accordingly with compressed air. In this case too, the thread stress can be reduced.

This makes it possible to process sensitive weft yarn at an exceptionally high speed of, for example, 400 min even with a large weaving width of five meters and more. The yarn is not damaged because the entire mass of the thread during acceleration (start of entry) is no longer set in motion by the entry element alone and conversely, at the end of entry, is no longer slowed down solely by the thread brake needs. In both cases, the movement (acceleration or deceleration) can be supported by the additional compressed air device between the supply spool and the thread transfer point.

• Fig. 1 zeigt schematisch die für die Erfindung wesentlichen Teile einer Projektil-Webmaschine,
• Fig. 2 una 3 veranschaulichen abgewandelte Ausführungsformen.

Further features emerge from the following description of exemplary embodiments in conjunction with the drawing and the claims.

• 1 schematically shows the parts of a projectile weaving machine essential for the invention,
• Fig. 2 and 3 illustrate modified embodiments.

In the weaving machine, the weft thread 1 is drawn off from a stationary supply bobbin 4 that remains outside the shed 3 formed by the warp threads 2. It first arrives at a drum store 5, then through a delivery device 6 consisting of two rollers running one on top of the other and from here into a blow store 7. This contains a pipe 9 standing transversely to the entry direction 8 and an air nozzle 11 blowing the thread 1 into this pipe a thread loop 12 is blown out.

The weft thread 1 is then passed through a deceleration nozzle (brake nozzle) 13 blowing against the entry direction 8, an acceleration nozzle 14 blowing in the entry direction 8, a thread clamp 15, a thread tensioner 17 movable in the direction of arrow 16 and a thread transfer nozzle 18 through which the weft thread 1 with its end 19 aer weft clamp 21 of the projectile 22 is presented. The projectile 22 can by the impact lever 23 in the shed 3 (Web wide W) can be shot. The fabric that arises at the stop 24 is designated by 25, the projectile brake located on the catch side 41 by 42.

If a weft thread 1 is to be inserted into the compartment 3, the projectile 22 must be positioned in the thread transfer position shown in FIG. 1 at the firing point. A control device of the weaving machine now emits a short air pulse from the thread transfer nozzle 18, whereby the thread end 19 is blown into the opened projectile clamp 21. The thread transfer point is designated 20.

The thread clamp 21 is then closed and the air pulse of the nozzle 18 is turned off. The impact lever 23 is pivoted clockwise in FIG. 1 and the projectile 22 is shot into the shed 3. At the same time, an air pulse is given in the acceleration nozzle 14 and the thread tensioner 17 is moved into the position 17a. The projectile 22 flies through the shed 3, the weft 1 is pulled under acceleration through the nozzle 14, the thread loop 12 in the store 7 being used up more or less. If necessary, thread is drawn from the memory 5.

Towards the end of the weft insertion, that is when the projectile 22 arrives at the catching side 41 of the weaving machine and is braked by the brake 42, the air pulse in the nozzle 14 is switched off and a pulse is given through the nozzle 13 in the direction of entry 8 in the opposite direction. This will slow down the weft. The thread brake 15 is then closed, causing the thread 1 to come to a complete standstill.

The projectile 22 is then defined in a Thread release position pushed back, which is exactly the same with every weft insertion. During the pushing back movement of the projectile 22, the thread tensioner is moved from the position 17a back to the starting position 17, as a result of which the weft thread is kept tensioned in the shed 3. The thread 1 is cut by a shear 26 on the weft side. Then the sheet of the inserted weft is struck against the tissue 25 by means of the reed 27.

In the embodiment according to FIG. 2, a thread guide tube 31, which is only indicated schematically, is arranged instead of the acceleration nozzle 14 and the deceleration nozzle 13. By feeding compressed air into a nozzle 32, the thread 1 can be accelerated, and by feeding compressed air into the nozzle 33, it can be reversed (braked).

In addition, in the variant according to FIG. 2, a controllable thread clamp 34 is installed between the drum store 5 and the blow store 7. It can be closed, for example, during the weft insertion, so that the weft thread length to be entered is removed from the blow memory 7 or the loop 12. When the entry is complete, terminal 34 is opened and terminal 15 is closed. The nozzle 11 now receives an air pulse, whereby a new loop 12 is formed in the memory 7.

In the example according to FIG. 3, no part corresponding to the blow memory 7.11 is installed between the parts 34, 31, and a thread clamp corresponding to the part 15 according to FIG. 2 is also omitted between the parts 31, 17.

Further variants result, for example, from the fact that in Fig. 1, the separate acceleration nozzle 14 is omitted and its function is taken over by the transfer nozzle 18. In this case, nozzle 18 receives an air pulse for thread transfer and a further air pulse when the thread is inserted into shed 3.

Furthermore, the device according to Fig. 1 can e.g. are controlled such that the piece of thread that is released when the thread tensioner 17 moves in position 17a is blown back into the loop 12 through the nozzle 13. Furthermore, e.g. the drum store 5 can be omitted and only one blow store 7, 11 can be provided. A whole number of different combinations of compressed air-controlled thread influencing parts in the area between the supply spool 1 and the thread transfer point 20 are possible.

A compressed air-fed device for influencing the weft thread movement in the described or a similar form can also be used, for example, in a belt rapier weaving machine in which, instead of a free-flying projectile 22, a rapier attached to an insertion banana moves through the compartment 3.

If the compressed air-fed device is to be used for influencing the weft thread movement during entry for a two- or multi-weft machine, a corresponding plurality of parts 4, 5, 1, 17, 18 shown in FIG. 3 will be installed, such an arrangement for each thread type Corresponding to FIG. 3. The type of thread to be entered in the compartment 3 is then presented to the projectile 22 at the thread transfer point 20 by a multi-shot device.

Claims (9)

1.Weaving machine with a weft supply spool (4) remaining outside the shed (3) and an entry element which penetrates the shed when the weft is inserted, e.g. Projectile (22), characterized in that between the supply spool (4) and a point (20) of the transfer of the weft thread (1) to the insertion element (22), a device fed with compressed air is provided for influencing the weft thread movement during the insertion. 2. Machine according to claim 1, characterized in that the compressed air-fed device contains a tubular element (31) connected to a compressed air source, through which the weft thread (1) is guided. 3. Machine according to claims 1 and 2, characterized in that the tubular element is a controlled compressed air nozzle (14) which blows in the entry direction (8) and through which the weft thread (1) is accelerated during the entry. 4. Machine according to claims 1 and 2, characterized in that the tubular element is a controlled compressed air nozzle (13) blowing against the entry direction (8), through which the weft thread (1) is braked during the entry. 5. Machine according to claims 1 and 2 and one of the following claims, characterized in that at the point (20) of the transfer of the weft thread (1) to the insertion member (22) a controlled thread transfer nozzle (18) for presenting the weft thread (1 ) is arranged. 6. Machine according to one of the preceding claims, characterized in that at least one weft thread store (5,9) is arranged between the supply spool (4) and the thread transfer point (20). 7. Machine according to claim 6, characterized in that the weft thread store is a mechanical drum store (5). 8. Machine according to aen claims 6 or 7, characterized in that the weft thread store is a compressed air fed, the weft thread (1) to a thread loop (12) extending transversely to the direction of entry (8) blow out memory (7). 9. Machine according to one of the preceding claims, characterized in that between the supply spool (4) and the thread transfer point (20) is provided with an arm which can be swung out transversely to the entry direction (8) and is provided with a thread deflector (17).

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