JP3246635B2 - Weft detection device for water jet loom - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a weft detecting device for detecting a weft inserted by an optical detecting means in a water jet loom.

[0002]

2. Description of the Related Art Conventionally, an optical weft detecting device of a water jet loom is, for example, disclosed in Japanese Patent Publication No. 57-13653. There is one in which a light emitter and a light receiver are arranged opposite to each other with a trajectory therebetween, the distance between the light emitter and the light receiver is narrowed, and water is always held in the gap by surface tension. This is because when water drops are scattered by the water jet at the time of weft insertion and this scattered water sometimes crosses between the light emitter and receiver, it is detected as noise, and also when the weft passes through the wet weft. To prevent water droplets from adhering to the light emitting and receiving device and causing noise. Then, water is always present between the light emitting and receiving devices, and there is no influence of the scattered water droplets, and the detection accuracy is improved.

However, in the case of the above technique, when vibrations accompanying weaving motion such as beating and rotation of a motor are transmitted to the light emitting and receiving devices, the water held between the light emitting and receiving devices fluctuates. If the light receiving amount is reduced and a waveform that becomes noise is detected and cannot be distinguished from a signal due to the passage of the weft, this noise may be erroneously detected as the weft.

[0004] Accordingly, Japanese Patent Application No. Hei.
As described in No. 3112, a signal obtained from the photodetector is differentiated to detect a change rate of the signal obtained from the photodetector, and a signal change rate detecting means obtained by the signal change rate detecting means. A comparison means for comparing the signal with a predetermined reference value; if the signal from the signal change rate detection means is larger than the predetermined reference value by the output of the comparison means, the signal is judged to be a weft; There has been proposed a weft detecting device for a water jet loom which is determined to be present.

[0005]

The weft detecting device for performing the above-described differential processing detects a rate of change of an output signal waveform when a weft enters between the light emitting and receiving devices, and compares the rate of change with a predetermined reference value. Then, since it is determined whether or not it is a weft yarn, it may not be possible to accurately determine whether the signal is a signal due to intrusion of a yarn or a water drop. That is, when a large vibration is suddenly applied to the detection device holding the light emitting and receiving devices, the water between the light emitting and receiving devices rapidly fluctuates, and the sudden change in the transmittance due to the fluctuation of the water causes a sudden change in the output signal of the light receiving device. Appears,
As in the case of the infiltration of the weft, there was a case where the signal suddenly changed. Also, when water jumps in from the outside between the light emitting and receiving devices, the water between the light emitting and receiving devices fluctuates rapidly, and a steep output signal change may occur as in the case of the infiltration of the weft. Further, if water does not exist between the light emitting and receiving devices and water jumps in from the outside between the light emitting and receiving devices, the output signal of the light receiving device also changes abruptly in the same manner as described above.

The present invention has been made in view of the above-mentioned problems of the prior art, and is directed to a water jet loom capable of performing accurate weft detection without being affected by noise signals due to fluctuations in water or the like. It is an object to provide a weft detection device.

[0007]

According to the present invention, a photoelectric sensor such as a photodiode provided facing a locus through which a weft to be beaten passes, and a rate of change of a signal obtained from the photoelectric sensor are detected. Signal change rate detecting means such as a differentiating circuit, and a value of a signal obtained by the signal change rate detecting means when the weft escapes from the detection unit of the photoelectric sensor among signals obtained by the signal change rate detecting means. For example, comparing the absolute value with a predetermined reference value, if the reference value is greater than or equal to the reference value, a comparison means for outputting a weft insertion success / failure determination signal that weft insertion has been successfully performed is provided. It is a weft detection device.

Further, according to the present invention, there is provided an integrating means such as an integrating circuit for integrating a signal obtained when the weft escapes from the detecting section among the signals from the signal change rate detecting means, and the integrating circuit. The value of the signal, for example the absolute value,
A weft detecting device for a water jet loom, comprising a comparing means for outputting a judgment signal of success or failure of weft insertion by comparing with a predetermined reference value. Further, between the signal change rate detecting means and the integrator, a signal such as a diode for passing a signal having the same sign as a signal obtained when the weft exits from the detection unit and removing the reverse signal is removed. Means are provided.

Further, the photoelectric sensor of the present invention comprises a light emitting element and a light receiving element, and the detecting portion is formed so that one end face of each optical fiber faces the locus of weft passage, and the other end of each optical fiber has The light emitting element and the light receiving element are arranged.

[0010]

According to the weft detecting device for a water jet loom of the present invention, the weft insertion is detected by the change rate of the signal obtained when the weft exits from the detecting portion of the photoelectric sensor. Signals caused by fluctuations of water or jumping in of water droplets during the time are ignored, and only signals due to a sharp output change when the weft escapes from the detection unit of the photoelectric sensor are reliably determined as the weft.

That is, the output signal of the photoelectric sensor when the weft enters the detection unit and when the weft exits the detection unit undergoes a large change, and the absolute value of the signal change rate is large. On the other hand, the signal obtained by the drop of the water drop may have a large change in the output signal when the water drop jumps into the detection section and the detection section may be drowned by water. When going out, the water cannot suddenly completely come out, and some water always remains attached to the detection unit due to the surface tension of the water. Therefore, the output signal of the photoelectric sensor when the water droplet leaves the detection unit does not change relatively largely. In addition, the signal due to the fluctuation of the water of the detection unit does not change as sharply as the output signal when the weft passes, and can be reliably distinguished. Therefore, by detecting the weft yarn based on the value of the output signal when the weft yarn leaves the detection unit, it is possible to completely overcome the noise caused by the sway of the water and the ingress and egress of the water.

In addition, since the moving speed of the weft at the detecting portion is reduced due to looseness of the weft and the like, even if the output level of the signal change rate detecting means is low, the period until the weft comes off becomes longer. By further integrating the signal obtained by the means, the signal at the time when the weft thread exits can be a relatively large value equal to or greater than a certain value, regardless of the magnitude of the output of the signal change rate detecting means.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 4 show a first embodiment of a weft detecting device for a water jet loom according to the present invention. As shown in FIGS. The warp 10 is provided at an end of the loom opposite to the weft insertion side, and is provided to face one end of a reed 12 through which a warp 10 opened by a heald (not shown) is inserted. One end of the reed 12 has an opening 1 for avoiding interference with the weft detecting device 11 during beating.
2a is formed. The weft 16 inserted by the water jet injected from the weft insertion nozzle 14 is inserted into the opening of the warp 10 at a predetermined weft insertion timing.

The weft detecting device 11 of this embodiment includes a holding member 20 having a narrow slit 18 through which the inserted weft 16 can pass, and a slit 18 sandwiching the slit 18 on both sides of the slit 18. Provided in the holding member 20,
At predetermined positions of the slit 18, there are optical fibers 22 and 24 which are light transmitting members whose one end faces each other. As shown in FIG. 1, a light emitting element 23 such as a light emitting diode is provided at the other end of the optical fiber 22, and a light receiving element 25 such as a photodiode or a phototransistor is provided at the other end of the optical fiber 24. Have been. The pair of light emitting element 23 and light receiving element 25 form the photoelectric sensor of the present invention. Detector 21 which is a portion where optical fiber 22 and end of optical fiber 24 of slit 18 face each other.
, Water is usually held by its surface tension. The holding member 20 is fixed to an attachment member 28 attached to a loom frame (not shown) so that the slit 18 is located on the movement locus of the beaten weft 16.

As shown in FIG. 1, the detection circuit of the weft detection device 11 of this embodiment is connected to the light emitting element 23, to which the output of the drive amplifier 30 is connected, so as to emit light constantly during operation of the loom. ing. The light receiving element 25 is connected to the input side of an amplifier 32 such as an operational amplifier. Amplifier 3
The output of 2 is connected to a non-inverting input terminal of a comparator 36 composed of an operational amplifier or the like via a differentiator 34 as a signal change rate detecting means. The inverting input terminal of the comparator 36 is grounded via a predetermined reference voltage _Vref . The output of the comparator 36 is connected to an AND gate 38. A timing signal that repeats ON and OFF at a predetermined timing corresponding to the weaving operation of a weaving machine (not shown) is connected to the AND gate 38. The ON period of the predetermined timing signal is a period between the timings at which the weft yarn 16 passes through the detection unit 21, and is, for example, a period from the completion of the weft insertion to the beating.

The operation of the weft detecting device 11 of this embodiment will be described with reference to FIG. First, during operation of the loom, light is constantly emitted from the light emitting element 23, and the light receiving element 25 is always in a light receiving state via the optical fibers 22 and 24, and outputs an output signal by light reception. In this state, the weft yarn 16 is inserted at a predetermined weft insertion timing, and the reed 12
When the beating is performed, the weft 16 passes between the end faces of the optical fibers 22 and 24 of the slit 18. Thereby, the weft 16 blocks the light from the light emitting element 23, and the output signal of the light receiving element 25 is output via the amplifier 32. The output signal A of the amplifier 32, as shown in the schematic waveform of FIG. 2, the output only during the period T ₁ in which the light is blocked is reduced. Then, the differentiator 34 outputs a differential signal B corresponding to the change rate of the signal A, and the differential signal B is input to the comparator 36,
It is compared with a predetermined reference voltage _Vref .

Here, this reference voltage V _ref is
In the signal B obtained by differentiating the output signal of the light receiving element 25 amplified by 2, the signal B is set to the same sign as the signal obtained when the weft 16 exits the detection unit 21, that is, to the plus side in this embodiment. The level is set within a signal level obtained when the weft yarn 16 exits the detecting section 21 between the slits 18 and is set to a value equal to or higher than a differential value due to other noise components. The output C of the comparator 36 is
When the differential signal B of the signal A when the weft yarn 16 leaves the detection unit 21 is higher than the reference voltage _Vref (H),
When it is low, it is (L).

Next, the output signal C is supplied to the AND gate 3
8 is input. The AND gates 38, a timing signal synchronized with the weaving motion of the loom, weft detection timing signal becomes during the period T ₂ of the from the weft insertion completion until beating point (H) is input. The weft detection timing signal is intended to define the weft detection period at the weft inserting weft 16 at the time of beating is a period including the period T ₁ of the passing through the slit 18. The output of the AND gate 38 is output as a weft detection signal D to a loom control device (not shown).

As a result, the weft yarn 16 is normally inserted into the slit 1
8, the change of the output signal A of the light receiving element 25 is relatively steep, and the weft 16
The output B of the differentiator 34 when exiting from the
_ref is obtained, and the output C of the comparator 36 becomes (H)
Then, a weft detection signal D indicating that the weft 16 has passed normally is output via the AND gate 38.

On the other hand, when the weft 16 does not cross the detecting portion 21 of the slit 18, for example, when the output of the light receiving element 25 changes due to fluctuation of the water of the detecting portion 21, the signal A becomes The waveform has a relatively gentle fluctuation, and the output B of the differentiator 34 can only obtain a signal equal to or lower than the reference voltage _Vref . Therefore, the output signal C of the comparator 36 remains (L), and the weft detection signal is not generated from the AND gate 38. Similarly, the detecting unit 2 of the slit 18
The fluctuation of the output signal A of the light receiving element 25 when water flows out of the line 1 is also relatively gentle, and the output B of the differentiator 34 can obtain only a signal equal to or lower than the reference voltage _Vref . Further, when water jumps into the detection unit 21 of the slit 18, even if the rate of change of the output signal A is sharp, the output B of the differentiator 34 at that time is opposite to the reference voltage _Vref. Is definitely excluded.

According to the weft detecting device 11 of this embodiment,
The passage of the weft 16 and the signal caused by the fluctuation of the water of the detecting section 21 of the slit 18 and the ingress and egress of the water are reliably distinguished, and accurate weft insertion detection is possible.

Next, a weft detecting device according to a second embodiment of the present invention will be described with reference to FIGS. Here, the same members as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. The weft detecting device 11 of this embodiment includes an amplifier 32
Is input to the differentiator 34 as in the first embodiment, and then the output signal of the differentiator 34 is changed to an integrator 4 having an integrating circuit.
This is what has been input to 0. Differentiator 34 and integrator 4
Between 0 and 0, a diode 42 serving as a signal selecting means is provided in parallel, and a signal of a sign on the side obtained when the weft 16 escapes from the detecting section 21 where the end faces of the optical fibers 22 and 24 are located, this embodiment. In this example, only the signal on the plus side enters the integrator 40.

The reference voltage V _ref set in the comparator 36 of this embodiment is different from the signal B obtained by differentiating the output signal of the light receiving element 25 amplified by the amplifier 32, by the weft 16 of the optical fibers 22 and 24. It is set to a value that is within the level of the integrated signal E with respect to the signal B obtained when exiting from the end face, and is equal to or greater than the integrated value of the other noise components.

The operation of the weft detecting device 11 of this embodiment is as follows.
As in the above embodiment, the signal input to the comparator 36 is a signal obtained by integrating the plus signal of the differentiator 34 by the integrator 40. Based on the signal integrated by the integrator 40, the signal obtained when the weft 16 exits the detecting portion 21 between the slits 18 is reliably detected as compared with the reference voltage _Vref .

This ensures that only the weft yarn is detected even when the speed at which the weft yarn 16 passes through the detecting portion 21 of the slit 18 becomes slow. That is, the weft 16
But normally passes through the detection unit 21 of the slit 18,
The waveform of the signal A shown in FIG. 6 as indicated by the solid line is obtained.
Can be detected. However, in some cases, as shown by the two-dot chain line in FIG. 6, the passing time of the weft 16 may be long.

As shown in FIG. 8, when the weft 16 is pushed by the reed 12 and passes through the detecting portion 21, the weft 16 is subjected to the resistance of water in the detecting portion 21 and the sliding surface of the slit 18. This is because the weft loosens in a substantially U-shape due to the resistance of the weft. When the slack is present, the weft 16 is slightly delayed from the point at which the reed 12 passes through the
Will pass through. On the other hand, the speed of the reed 12 in the beating motion is a speed at which a sine curve is drawn. The speed decreases as the reed 12 approaches the cloth fell, and the moving direction is reversed after the beating. Accordingly, if the weft 16 is loose on the rear side with respect to the moving direction, the timing at which the weft 16 passes through the detection unit 21 is delayed, and the weft 16 is pushed by the reed 12 and moves. The weft 16 passes through the detection unit 21 at the point in time when the speed becomes slow. And reed 1
When the weft 16 comes out of the detection unit 21 at the point in time when the speed of the signal 2 becomes slow, the slope of the rising side of the signal A becomes gentle and the level of the differential signal B becomes relatively high, as shown by the two-dot chain line in FIG. It will be low.

On the other hand, the weft 16 always crosses the detecting section 21, and even if the moving speed is slow, the time required for the weft 16 to escape from the detecting section 21 is longer. Therefore, even if the level of the differential signal B is low, if the integrated value of the signal A when the weft 16 exits while the differential signal B is being output is taken, the weft 16 exits regardless of the magnitude of the differential signal. In this case, the integration signal has a relatively large value equal to or larger than a certain value. By setting the reference voltage _Vref as described above based on the integration signal, the passage of the weft yarn 16 can be reliably detected.

According to the weft detecting device of this embodiment, the weft insertion is performed normally, but the weft is smoothly detected by the detecting unit 2.
Even when the detection signal A does not pass through 1 and changes slowly, the weft insertion is reliably detected, and an erroneous weft insertion error signal is not output.

The weft detecting device according to the present invention detects the rate of change of the output of the photoelectric sensor when optically detecting the weft, and based on the change rate of the signal when the weft exits the detection unit, the signal is used as a basis. What is necessary is just to detect the weft, and the type of the light emitting element and the light receiving element is not limited.
Further, as shown in FIG. 7, the detection unit of the present invention may be a reflection type in which one end of an optical fiber as a light transmitting member is formed side by side facing a weft passage locus, Further, if necessary, a light reflecting portion 26 of black, white, or a mirror surface may be formed to face each optical fiber with the weft passage locus interposed therebetween.

The light transmitting member may be a combination of a lens and a mirror other than the optical fiber, and may be a member such as glass or transparent resin provided separately or integrally on the front surface of the light emitting element and the light receiving element. It may be. Further, the light transmitting member may be omitted and the light emitting element and the light receiving element may be provided directly facing the weft passage locus. Further, instead of constantly emitting light during the operation of the loom, the light emitting element may emit light only during a period necessary for weft detection, for example, only during a period in which a weft detection timing signal is input.
Similarly, the light receiving element may be operated only during a period necessary for weft detection. Further, similar to that of Japanese Patent Publication No. 57-13653, the slit 1
In order to prevent the jet water from directly jumping into the detection unit 8 of FIG. 8, a shielding plate of an appropriate shape may be provided on the weft insertion side of the slit 18.

[0031]

According to the weft detecting device for a water jet loom of the present invention, a predetermined reference value is determined based on a signal when the weft exits from the detecting portion among the signals obtained by the signal change rate detecting means. Since the comparison is made, there is no erroneous detection of the weft yarn due to water or the like, and accurate weft yarn detection becomes possible.

In particular, of the signals obtained by the signal change rate detecting means, the signal when the weft exits from the detecting portion is further integrated and compared with a predetermined reference value, so that the weft passing speed is low. Also in this case, there is no possibility that weft passage cannot be detected, and there is no erroneous detection of the weft due to water or the like, so that more accurate weft detection can be performed.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a weft detection circuit of a first embodiment of a weft detection device of the present invention.

FIG. 2 is a time chart showing an operation of the weft detecting circuit according to the first embodiment of the present invention.

FIG. 3 is a partial perspective view showing the weft detecting device of this embodiment.

FIG. 4 is a plan view showing the weft detecting device of this embodiment.

FIG. 5 is a circuit diagram of a detection circuit according to a second embodiment of the weft detection device of the present invention.

FIG. 6 is a time chart showing the operation of the weft detecting circuit according to the second embodiment of the present invention.

FIG. 7 is a diagram showing a modified example of the weft detecting device of the present invention.

FIG. 8 is a diagram illustrating the loosening of the weft during beating of the loom of the present invention.

[Explanation of symbols]

 Reference Signs List 11 weft detecting device 16 weft 18 slit 20 holding member 21 detecting portion 22, 24 optical fiber (light transmitting member) 23 light emitting element 25 light receiving element 30, 32 amplifier 34 differentiator 36 comparator 40 integrator

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-136639 (JP, A) JP-A-48-41069 (JP, A) JP-A-63-154687 (JP, U) 13653 (JP, B1) Jikku Sho 61-33013 (JP, Y2) (58) Fields investigated (Int. Cl. ⁷ , DB name) D03D 51/18-51/46

Claims (4)

(57) [Claims] 1. A photoelectric sensor provided so as to face a locus through which a beaten weft passes, signal change rate detecting means for detecting a change rate of a signal obtained from the photoelectric sensor, and a signal change rate And comparing means for comparing the value of the signal obtained when the weft thread exits from the detection unit of the photoelectric sensor among the signals obtained by the detection means with a predetermined reference value and outputting a determination signal of success or failure of weft insertion. Weft detector for the water jet loom provided. 2. A photoelectric sensor provided to face a locus through which a beaten weft passes, signal change rate detecting means for detecting a change rate of a signal obtained from the photoelectric sensor, and a signal change rate Integrating means for integrating a signal obtained when the weft escapes from the detecting section of the photoelectric sensor among signals from the detecting means, and comparing a value of the signal obtained by the integrating means with a predetermined reference value. A weft detecting device for a water jet loom, comprising a comparing means for outputting a weft insertion success / failure determination signal. 3. The photoelectric sensor comprises a light emitting element and a light receiving element. The detecting section is formed such that one end face of each optical fiber faces a weft passage locus, and the other end of each optical fiber emits light. The weft detecting device for a water jet loom according to claim 1 or 2, wherein the element and the light receiving element are arranged. 4. A signal having the same sign as that of a signal obtained when the weft exits from the detection unit of the photoelectric sensor is passed between the signal change rate detection means and the integrator, and a reverse signal is removed. 3. A signal selecting means for providing a signal
Or a weft detection device for a water jet loom according to 3.