JPH0615734B2 - Weft tension detector for loom - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a weft tension detector for detecting the tension at the end of weft insertion of a weft.

<Prior Art> According to Japanese Patent Application No. 59-149663, the present applicant proposes a weft tension detector for detecting the tension at the end of flight of a weft in a fluid jet loom in which a weft is inserted by a weft insertion nozzle. Control of a fluid-jet loom comprising: a tension at the end of flight of the weft and a reference tension, and control means for controlling the fluid supplied to the weft insertion nozzle or the rotational speed of the loom main spindle in accordance with the difference. Proposed a device.

FIG. 4 shows an example of the above control device, which will be described.

The weft storage device 1 is disclosed, for example, in Japanese Examined Patent Publication No. 59-32577, in which the winding pipe 3 rotates around the drum 2 at a constant speed to wind the weft yarn 4 around the drum 2, and the locking pin 5, When the weft yarn 4 moves in and out of the drum 2 peripheral surface at a predetermined timing, the weft yarn 4 is separately stored for one pick between the locking pins 5 and 6, and then the weft insertion is performed by retracting the locking pin 6. The weft insertion is performed by air injection of the main nozzle 8 through which the weft yarn 4 is guided through the weft guide 7, and the weft yarn 4 is unwound while being unwound from the drum 2, and the weft yarn 4 being rewound is retained by the locking pin 5. The weft insertion is completed when locked in. 9 is a warp yarn, 10 is a cloth cloth, and 11 is a woven cloth.

An electric-pneumatic proportional valve having a function of adjusting the air pressure proportional to an electric signal from a pressure air supply source to the main nozzle 8.
12, an air tank 13 that stores an air amount equivalent to approximately one pick, a solenoid valve 14 that is opened by turning on the start preparation switch of the loom and closed by stopping the loom, and a cam 15 that rotates in conjunction with the main shaft of the loom By means of this, pressurized air is supplied through the mechanical valve 16 that opens at a predetermined time of the weaving cycle, that is, at the weft insertion time. 17 is a pressure gauge.

A digital signal from a control circuit 18 is converted into an analog voltage via a D / A converter 19 and input to the electric-pneumatic proportional valve 12, and the control circuit 18 receives a control input from a weft tension detector 20 as a control input. And the signal from the presetter 21 are input.

The weft tension detector 20 detects the tension of the weft 4 at the end of the flight, and is attached to the side wall of the locking pin 5 to fix the weft 4.
A strain gauge that detects the deflection when the is locked, or a piezoelectric element that directly detects the impact at that time is used. The presetter 21 is provided to set information (reference tension etc.) necessary for control by the control circuit 18.

Here, the control circuit 18 compares the tension at the end of flight of the weft yarn 4 detected by the weft tension detector 20 with the reference tension preset by the presetter 21, and according to the comparison result, the electro-pneumatic proportional valve 12 The supply pressure to the main nozzle 8 is controlled via.

That is, when the weft insertion is performed by the injection of the pressurized air from the main nozzle 8 and the weft 4 is locked to the locking pin 5, the tension of the weft 4 at this time is detected by the weft tension detector 20. In the control circuit 18, the detected tension is compared with the reference tension, and when the detected value is smaller, the electric-pneumatic proportional valve 12 increases the supply pressure to the main nozzle 8 to increase the flying speed of the weft thread 4. As a result, the tension at the end of flight is made to approach the reference tension. On the contrary, when the detected value is larger, the electric-pneumatic proportional valve 12 lowers the supply pressure to the main nozzle 8 to lower the flying speed of the weft 4, and the tension at the end of flying is set to the reference tension. Try to get closer.

<Problems to be Solved by the Invention> However, in the above control device, the weft yarn 4
It was found that the weft tension detector 20 for detecting the tension when the hook is locked by the locking pin 5 has the following problems.

That is, when the weft thread 4 is locked to the locking pin 5 at the end of weft insertion, as shown in FIGS. 5 and 6, the weft thread 4A to be weft-inserted at the time of the next weft insertion is already wound a plurality of times. Therefore, the taper portion 2A of the drum 2 slides down and is caught by the locking pin 5 to apply a lateral force to the main nozzle 8 side.

This will be described with reference to FIG. 7. The tension T of the weft thread 4A is
_A lateral force F ₁ is applied to the locking pin 5 by the resultant force of _{1 and} T ₂ . Further, a lateral force T ₃ also acts on the locking pin 5 by a force F ₂ that slides down the taper portion 2A of the drum 2 caused by the tensions T _{1 and} T ₂ of the weft yarn 4A. Therefore, the lateral force of F _0, which is the sum of the forces F ₁ and T ₃ , is applied to the locking pin 5.

Therefore, even just before the weft yarn 4 is engaged with the engaging pin 5, the locking pin 5 is not flexed by F _0, the weft detector 20, for example from strain gauges, is proportional to the force F ₀ An electrical signal is being output.

On the other hand, when the weft thread 4 is locked by the locking pin 5, a resultant force F ₃ due to the tensions T _5, T ₆ proportional to the impact force at that time acts on the locking pin 5. Weft tension detector 20, so that it can best detect the force F _3, is adhered to the surface perpendicular to the force F _3.

However, in the case of using a thin and weak weft yarn 4 of about 40 denier, in order to prevent the weft yarn 4 from being cut, the reference tension is set low and the supply pressure to the main nozzle 8 is low, that is, the flying speed of the weft yarn 4 Since the thread is thin, the fact that the thread is thin also means that the mass is small.
There is an impact force or the force F ₃ acts on the locking pin 5 when it is engaged with the engaging pin 5 is reduced.

Then, there occurs a situation in which the output of the weft tension detector 20 does not change even if the force F ₃ is applied to the output of the weft tension detector 20 caused by the lateral force F ₀ of the weft yarn 4A to be inserted next time. Sometimes. Thus weft tension detector 20
If the output change does not occur, the tension cannot be detected and the control becomes impossible.

Therefore, in view of such problems, the present invention provides a weft tension detector that can reliably detect the tension when the weft is locked by the locking pin even when a thin and weak weft is used. The purpose is to do.

<Means for Solving Problems> In order to achieve the above-mentioned object, the present invention operates locking pins for locking wefts at the same timing at positions shifted in the weft rewinding direction at the end of weft insertion. It is divided into two pins, and of these pins, the pin on the upstream side in the weft rewinding direction is displaced to the weft insertion side with respect to the pin on the downstream side in the weft rewinding direction, and the weft tension detector is attached to this upstream pin. It was done like this.

<Action> That is, the lateral force of the weft thread to be inserted next time to the pin on the upstream side is reduced or reduced to zero, and only the force when the weft thread is locked to this pin acts. Then, the weft tension at that time is surely detected.

<Embodiment> An embodiment of the present invention will be described below with reference to FIGS.

The locking pin 5 is moved in the same manner as the conventional one,
Its tip is bifurcated and has pins 5A and 5
It is divided into B. The pin 5A is located upstream of the pin 5B in the unwinding direction of the weft yarn 4 (direction A in the drawing),
Moreover, it is deviated to the weft insertion side (right side in the figure) from the pin 5B. A weft tension detector, for example, a strain gauge 20 is attached to the pin 5A. 22 is the lead wire.

In this way, the pin 5A is divided into the two pins 5A and 5B, and the pin 5A having the weft tension detector, that is, the strain gauge 20 attached thereto is arranged on the upstream side of the other pins 5B in the weft rewinding direction so as to be displaced toward the weft inserting side. In the case, weft yarn 4A to be inserted next time
1 is locked to the pin 5B as apparent from FIG. 1, does not act on the pin 5A, and the weft yarn 4 in which the weft is inserted is locked to the pin 5A at the end of the weft insertion.

Therefore, the above-mentioned force F ₀ is applied to the pin 5B, and the force F ₃
Since only the weft thread is applied to the pin 5A, even if a thin and weak weft thread is used, the weft thread 4 being weft-inserted is locked by the locking pin 5 without being affected by the tension of the weft thread 4A to be inserted next time. The tension at the time can be detected.

In this case, the strain gauge 20 is preferably attached at a position on the longitudinal extension of the portion of the pin 5B with which the weft thread 4 abuts, and a position on the back side of that position, as shown in FIGS. Of course, as a weft tension detector, a strain gauge
Other than 20, a piezoelectric element or the like may be used.

The locking pin 5 is not bifurcated as in the embodiment, but the pins 5A and 5B may be provided completely separately and driven separately.

The weft tension detector according to the present invention can be used not only in the control device for the supply pressure to the main nozzle described above, but also in various control devices, and can of course be used when only the tension of the weft yarn is detected.

Further, the weft inserting device is not limited to one using a fluid jet nozzle, and may be a gripper shuttle system.

Further, the weft storage drum is not limited to the cylindrical shape, but may be a substantially cylindrical shape by arranging a plurality of rollers in a frame shape.

<Effects of the Invention> As described above, according to the present invention, when the weft-inserted weft is locked by preventing the force of the weft inserted next time from acting on the pin to which the detector is attached. Since it is possible to take out only the force of, the effect is obtained that the tension when the weft is locked by the locking pin can be reliably detected.

[Brief description of drawings]

FIG. 1 is a side view of a drum showing an embodiment of the weft tension detector according to the present invention, FIG. 2 is a perspective view of an essential part of the same, and FIG. 3 is an enlarged view of an essential part of FIG. 1 and FIG. Is a schematic configuration diagram of a weft insertion control device in which the weft tension detector according to the present invention is used, FIG. 5 is a side view of a drum showing conventional problems, and FIG. 6 is an enlarged view of an essential part of FIG. 7 (A) and 7 (B) are views for explaining the force acting on the locking pin. 2 ... Drum, 4 ... Weft, 5 ... Locking pin, 5A, 5
B: pin, 8: main nozzle, 20: weft tension detector (eg strain gauge)

Claims (1)

[Claims] 1. A weft yarn wound and stored on a drum (2).
(4) is rewound from the drum (2) by the weft insertion device (8) and weft-inserted, and the weft thread (4) being rewound at a predetermined timing comes in and out of the drum (2) locking pin (5). ) To restrict the weft insertion length for one pick by stopping the weft insertion, and the weaving loom is attached to the locking pin (5) to engage with the locking pin (5). A weft tension detecting device (20) for detecting the tension of the weft (4) when stopped, wherein two locking pins (5) are operated at the same timing at positions shifted in the weft rewinding direction. The pin (5A, 5B) is divided into the pins (5A, 5B), and the pin (5A) on the upstream side in the weft rewinding direction is displaced to the weft insertion side from the pin (5B) on the downstream side in the weft rewinding direction. A weft tension detector for a loom, which is mounted on a pin (5A).