JPH0447052B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Technical Field> The present invention relates to a method for operating a weft pull-back device in a fluid jet loom.

<Prior Art> As a conventional weft pulling back device, there is one shown in FIG. 1, for example. To explain this, the weft gripper 2 on the frame 1 side and the reed holder 3
Weft insertion nozzle 4 attached to the weft insertion side end of
A pull-back lever 6 having a yarn guide 6a is disposed on the path of the weft yarn 5 between the
is made to swing by a cam 7 via a swing lever 8 and a shaft 9.

That is, after the beating of the inserted weft yarn is completed and the weft yarn is cut by the cutter at the end of the woven fabric on the weft insertion side, the pull-back lever 6 begins to gradually rise, thereby causing the weft gripper 2 and the weft yarn to be cut off by the cutter. The yarn path of the weft yarn 5 is bent between the weft yarn 5 and the insertion nozzle 4 with the yarn guide 6a of the pull-back lever 6 as the apex. At this time, while the weft thread gripper 2 is holding the weft thread 5, the nozzle 4 side is not restraining it in any way, so as the pull-back lever 6 is raised, the weft thread length coming out from the tip of the nozzle 4 after cutting is It gradually decreases. Therefore, it is possible to prevent the weft yarn 5 coming out from the tip of the nozzle 4 from becoming entangled with the warp yarn when the weft yarn 5 is stretched straight especially by the advance injection before the start of weft insertion. Then, around the time when the timing of the advance injection starts, the pullback lever 6 starts to descend, gradually decreasing the amount of bending of the weft yarn, and moving the weft yarn 5, which has been straightened by the advance injection and coming out from the tip of the nozzle 4, into the warp. Insert it into the opening. Of course, the bending of the weft yarn 5 is completely eliminated by the time the weft insertion is started (the weft gripper 2 is opened) to prevent flying resistance. Incidentally, FIG. 2 shows the operating characteristics of a conventional weft pullback device.

By the way, in the past, the main weft storage device was the so-called air pool method, which stores the measured weft yarn in a suspended state due to air currents, but in recent years, the so-called air pool method has been used for the purpose of saving energy or increasing versatility. , So-called drum-type weft storage devices that store weft yarns by wrapping them around a drum are becoming popular.In this case, the weft flying resistance during weft insertion becomes smaller than necessary, and the weft insertion speed becomes excessively high. As a result, the weft yarn is subjected to an impact at the end of weft insertion, which may cause the weft yarn to break, although in rare cases, and the weft yarn stored in the drum becomes almost unrestrained at the time of weft insertion, for example. When spun yarn is used for the weft, the fuzz of the weft gets entangled with each other and unravels all at once.
Tangle of the weft threads also occurred.

<Object of the Invention> In view of the above-mentioned problems, it is an object of the present invention to make it possible to maintain an appropriate state during weft insertion by using a weft pull-back device.

<Structure of the Invention> For this reason, the present invention, when operating the weft pulling back device, pulls back the weft by maximizing the bending amount of the weft after cutting the weft at the end of the weft insertion side woven fabric after beating the reed. At the beginning of weft insertion, the amount of bending of the weft yarn is gradually reduced, and during this reduction process, flying resistance is applied while decreasing to prevent weft entanglement, and at the end of weft insertion, the amount of bending of the weft yarn is gradually increased, In this increasing process, flying resistance is applied to prevent weft breakage.

<Example> Examples will be described below.

In FIG. 3, the weft yarn storage device winds the weft yarn 5 from a yarn feeder (not shown) around the drum 10 by means of a winding guide 11 that rotates around the drum 10 held in a stationary state, and winds the weft yarn 5 from the drum 10 outside the drum 10. The first
By moving the second locking bodies 12, 13 into and out of the holes 14, 15 of the drum 10 at predetermined timing, the wound weft 5 is transferred between the first and second locking bodies 12, 13. It is something to store. (still,
Such a weft storage device was filed in a patent application filed in 1983 by the present applicant.
It was previously proposed in No. 86497. ) The weft 5 from the drum 10 of the weft storage device is passed through the weft gripper 2, the yarn guide 6a of the pull-back lever 6, and the weft insertion nozzle 4 in this order. The weft gripper 2 may be omitted depending on the case.

In order to carry out the present invention, the cam 7 for operating the pull-back lever 6 has a cam ridge having three heights: a high part H, a middle part M, and a low part L, as shown in FIG. At the high part H, the weft bending amount becomes a minimum value (0), and at the low part L, the weft bending amount takes a maximum value. If the reed beating is 0° and the weft insertion is 105° to 250°, then, for example, 30° to 50° is the connecting part ML from the middle part M to the lower part L for pulling back after weft cutting, and 95° to Connecting part LH from low part L to high part H to provide flying resistance (preventing weft entanglement) while decreasing 135°,
200° to 225° serves as a connecting portion HM from the high portion H to the middle portion M for imparting flying resistance (preventing weft breakage) while increasing.

Next, the operation will be explained with reference to FIG.

At the time of reed beating (0°), the pullback lever 6 is moved by the middle part M of the cam 7, and the weft yarn 5 is slightly bent.

Thereafter, when the beaten weft yarn 5 is cut at the end of the woven fabric on the weft insertion side, the connecting portion ML (30° to 50°) from the middle part M to the lower part L of the cam 7 pulls back the pull-back lever 6.
is driven, and when it moves to the lower part L, the amount of bending of the weft yarn 5 reaches its maximum value, and the weft yarn 5 is pulled back significantly. This is so-called pulling back after weft cutting, and is intended to prevent the weft tip from being woven back during the next weft insertion.

After that, the second locking body 13 is inserted into the hole 15 of the drum 10.
When the weft gripper 2 is opened, the weft 5 stored between the first and second locking bodies 12 and 13 is pulled out by the weft insertion nozzle 4, and weft insertion begins. From a little before the start of weft insertion (105°) (95°), from the lower part L of the cam 7 to the higher part H
The connecting part LH (95° to 135°) acts, the pulling back state is gradually released and the amount of bending of the weft yarn 5 decreases, and at an appropriate time (135°) after weft insertion starts, it is not pulled back at all. state (bending amount 0). Therefore, at the initial stage of weft insertion (105° to 135°), the weft 5 is still bent, and in the drum-type weft storage device, the weft 5 wound around the drum 10 during weft insertion is almost unrestrained. As a result, the weft yarns 5 were unwound from the drum 10 all at once, causing weft tangles. However, in this case, resistance is generated at the bending part of the weft yarns when the weft yarns start flying, so that the weft yarns are unwound from the drum 10 all at once, resulting in weft tangles. Since running resistance is appropriately applied, weft yarn tangles do not occur, and this running resistance gradually decreases, so sudden force is not applied to the weft yarns.

Then, from an appropriate time (135°) after weft insertion starts, the bending amount is maintained at 0, and when weft insertion ends (250°).
From the previous appropriate time (200 degrees), the pull-back lever 6 is gradually driven by the connecting part HM (200 degrees to 235 degrees) from the high part H to the middle part M of the cam 7, and the amount of bending is gradually increased, and the middle reach the value. As a result, flying resistance is gradually applied to the weft yarn 5 again at the final stage of weft insertion (200° to 250°), and the weft yarn 5 is appropriately braked by the end of weft insertion. Therefore, at the end of weft insertion, it is possible to alleviate the large impact force when the weft yarn 5 is stopped suddenly by the second locking body 13 due to the traction force of the weft insertion nozzle 4, and the weft yarn It is possible to prevent the cutting accident described in No. 5.

<Effects of the Invention> As explained above, according to the present invention, it is possible to apply resistance to the weft yarn according to its state by using the weft yarn pulling device, and it is possible to prevent the weft yarn from being cut or entangled. . In addition, in implementation,
Since a cam or the like based on the gist of the present invention can be replaced with a conventional pull-back device, there is also the advantage that there is no need to make major changes to the device.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the configuration of a conventional weft pulling device, FIG. 2 is a diagram showing the operating characteristics of the conventional weft pulling device, and FIG. 3 is a perspective view showing the configuration of an embodiment of the present invention. FIG. 4 is an enlarged view of the cam in the same embodiment, and FIG. 5 is a diagram showing the operating characteristics of the weft pulling device, etc. in the above embodiment. 2... Weft gripper, 4... Weft insertion nozzle, 5... Weft, 6... Pull-back lever, 7... Cam, 10... Drum, 11... Winding guide, 12... First locking body, 13
...Second locking body.

Claims (1)

[Claims] 1. Activate the weft pulling back device 6 which is disposed between the weft storage device 10 and the weft insertion nozzle 4 and pulls back the weft 5 inserted into the weft insertion nozzle 4 by bending the weft 5. At this time, after the weft is cut at the end of the woven fabric on the weft insertion side after beating, the amount of bending of the weft 5 is set to the maximum value and the weft 5 is pulled back, and the amount of bending of the weft 5 is gradually reduced at the beginning of weft insertion, In this decreasing process, the flying resistance of the weft yarn 5 is gradually reduced, and the amount of bending of the weft yarn 5 is gradually increased in the final stage of weft insertion, so that flying resistance is imparted to the weft yarn 5 in this increasing process. A method for operating a weft pull-back device in a fluid jet loom, characterized by: