JP3447919B2 - Transmission type weft detector - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmissive weft detecting device for a loom, and more particularly to an optical transmissive weft detecting device for projecting light from a light projector toward a light receiver.

[0002]

2. Description of the Related Art As one of optical weft detection devices using a light transmitter and a light receiver opposed to each other, JP-A-7-
There is a transmission type weft detection device described in Japanese Patent No. 42047. This conventional transmissive weft detection device irradiates light from the projector to the flight area of the weft, receives the light passing through the flight area by the light receiver, and when the weft cuts off the light incident on the light receiver. The presence or absence of weft is detected from the amount of decrease in the amount of light received by the light receiver.

However, in the loom, the weft thread rarely passes outside the original flight area. In such a case, the weft blocks the light, but the interception cannot be detected by the light receiver, and therefore the conventional weft detection device cannot detect the presence of the weft. In this way, if the presence of the weft is not detected, it is determined that the weft insertion is defective even though the weft has reached the counter-feed side,
As a result, the loom becomes dry.

If the light receiving area of the light receiving device is increased to prevent this, the light receiving device must be made large. For example, even if the amount of light received decreases due to the blocking of light described above,
The ratio of the amount of decrease in the amount of received light due to the blocking of the weft to the total amount of light incident on the light receiver is low, and as a result, the accuracy of weft detection is reduced.

[0005]

An object of the present invention is to increase the weft detection range without increasing the light receiving area of the light receiver.

[0006]

SOLUTION, ACTION, EFFECT The transmission type weft detection device of the present invention uses at least the first and second output signals from the light receiver.
Branching signal for branching to the branching signal, first detecting means for outputting a first electric signal corresponding to a decrease in the amount of light incident on the light receiver based on the first branching signal, and second branching Second detection means for outputting a second electric signal corresponding to an increase in the amount of light incident on the light receiver based on the signal, and a judgment for judging the presence or absence of a weft based on the first and second electric signals And means.

The light incident on the light receiver is classified into so-called direct light that is directly incident on the light receiver from the light emitter, and so-called reflected light that is incident after being reflected on the weft yarn passing near the outside of the direct light passage region. When the weft is not present in the detection area, the amount of light incident on the light receiver is only direct light, which is a substantially constant amount.

However, when the weft yarn exists in the direct light passage region, the weft yarn blocks the direct light incident on the light receiver, so that the amount of light incident on the light receiver is reduced, and as a result, the weft yarn is detected. Further, when the weft exists in the passing area other than the passing area of the direct light from the passing area of the irradiation light, the reflected light from the weft enters the light receiver together with the direct light, so that the amount of incident light to the light receiver increases, As a result, the weft is detected.

The presence or absence of the weft thread is determined, for example, by the presence of the weft thread when the amount of light incident on the light receiver decreases by a predetermined amount and when the amount of light incident on the light receiver increases by a predetermined amount. Can be determined. as a result,
The detection range of the light receiver is expanded to the passage area of the reflected light that can enter the light receiver, in addition to the passage area of the direct light incident on the light receiver.

According to the present invention, the output signal from the photodetector is branched into the first and second branch signals, and the first electric signal corresponding to the decrease in the amount of light incident on the photodetector is output. In addition to the first detection means, a second detection means for outputting a second electric signal corresponding to an increase in the amount of incident light on the same light receiver is provided, and based on the first and second electric signals, Since the presence / absence of the weft is determined, the weft detection range is increased without increasing the light receiving area of the light receiver.

The first electric signal is a signal corresponding to the decrease amount of the incident light amount to the light receiver, and the second electric signal is a signal corresponding to the increase amount of the incident light amount to the light receiver. After adding the 1st and 2nd signals, the presence or absence of the weft can be determined using the added signals. The addition of the first and second signals can be performed after inverting the polarity of either one.

A frosted glass is preferably arranged on the light emitting side of the projector. In this way, due to the characteristic of the frosted glass that scatters light, the detectable region becomes wider and the weft yarn can be detected more accurately.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, one embodiment of the structure of the light transmission type weft detection device 20 shown in FIGS. 1 to 6 will be described. The transmissive weft detection device 20 is arranged in the loom as an optical weft detection device that detects the wefts that have been inserted.

The weft detecting device 20 includes a first support 24 mounted on a lead holder 22 of a loom, and a plate-like and opaque second support fitted to one end of the first support 24. 26, a transparent cover 30 for covering the second support 26 so as to form a notch 28 in which the wefts fly, and the notch 28
And the notch 2 arranged on one side with respect to
8 on the other side.

The notch 28 has substantially the same shape as the weft guide groove of the reed not shown. The reed is attached to the lead holder 22. The weft detecting device 20 is assembled to the lead holder 22 in the first support 24 so that the cutout portion 28 is aligned with the weft guide groove of the reed.

One end of the first support 24 has a plate-shaped portion 38.
And has a recess 40 facing the weave side.
On the other hand, the other end portion of the first support 24 is the mounting portion 42 mounted on the lead holder 22, and the convex portion 44.
Is fitted in the recess of the lead holder 22, the inclined convex portion 46 is brought into contact with the side surface of the lead holder 22, and the inclined surface 48 is brought into contact with the inclined surface of the lead holder 22. To be done. The first support body 24 has a protrusion 50 projecting inside the upper portion of the recess 40 at one end, and a hole 52 through which a mounting bolt is inserted at the other end.

The second support 26 is a bottom surface of the recess 40,
It has a rear surface, an upper surface and a lower surface that are substantially the same as the upper surface and the lower surface. The second support member 26 has a recess 54 formed by cutting out a front portion of the second support member 26, and the protrusion 50 of the first support member 24.
Has a recess 56 fitted therein, and is arranged in the recess 40 of the first support 24 so that the recess 54 is on the front side.

The second support 26 also has a pair of vertically extending holes 58 and 60 for accommodating the light projector 32 and the light receiver 34, respectively, and an elongated pair of holes 58 and 60 communicating with the recess 54, respectively. Has slits 62 and 64 facing each other through the recess 54, and has a projection 66 projecting into the recess 54 at the center of the bottom of the recess 54. The slits 62, 64 extend in a direction intersecting the weft flying direction (depth direction of the cutout portion 28).

The cover 30 has a first cover portion 30a forming a surface of the cutout portion 28 on the side of the projector 32, and a second cover portion 30b forming a surface of the cutout portion 28 on the side of the light receiver 34.
Third cover portion 30c forming the inner bottom surface of the cutout portion 28
A fourth cover portion 30d that covers the front surface of the weft in the flight direction, a fifth cover portion 30e that covers the rear surface of the weft in the flight direction, and an upper portion of the second support 26. A sixth cover portion 30f for covering the front surface and a second support 26
A seventh cover portion 30g that covers the lower front surface of the third cover portion, an engagement step portion 30h formed at the lower end portion of the front surface of the seventh cover portion, and a through hole 68 formed in the center of the third cover portion 30c. Have.

The first, second and third cover portions 30a,
30b and 30c each have a substantially uniform thickness dimension. Second and third cover parts 30b and 30
The angle formed by c is a right angle.

The cover 30 is adhered to the second support 26. In the assembly of the second support 26 and the cover 30, the engagement step portion 30h of the cover 30 engages with the engagement portion of the first support 24, and the projection 66 of the second support 26 covers the cover. The first support 24 is fitted into the through hole 68 of the first support 24.
Is fitted in the recess 40 and is bonded to the first support 24. The protrusion 66 prevents the irradiation light from passing through the inside of the third cover portion 30c and reaching the light receiver 34 side.

The projector 32 and the receiver 34 are arranged in the holes 58 and 60, respectively, and the electric wire 72 is connected to the connector portion 70 provided at the lower end of the first support 24.
And 74. The light emitted from the light projecting device 32 to the cutout portion 28 through the slit 62 enters the light receiving device 34 through the slit 64. The light projector 32 and the light receiver 34 face each other, and the slits 62 and 64 also face each other.

The slits 62 and 64 respectively transmit light having a strip-shaped cross section which is long in the depth direction of the cutout 28 and short in the weft flight direction.
I will guide you to. As a result, the sensing area of the light receiver 34 in the flight direction of the weft becomes narrower, so that the presence or absence of the weft can be accurately detected.

A long semi-cylindrical lens extending in the longitudinal direction of the slit 62 may be arranged between the slit 62 and the projector 32. Specifically, in this kamaboko type lens, the arcuate lens is arranged so that the chord direction is the width direction of the slit 62 and the convex surface of the lens is on the slit 62 side.
The kamaboko lens covers the entire light emitting surface of the projector 32. Therefore, by arranging the kamaboko type lens, the irradiation light from the light projector 32 can be focused on the slit 62.

The bottom surface 28a of the recess 28 is a flat surface,
The first cover portion 30a of the cover 30 is formed in a plate shape having the same thickness dimension. The first cover portion 30a is
It is inclined at a predetermined angle with respect to the inner bottom surface 28a so that it becomes higher toward the inner bottom surface 28a. The projector 32 is a projector 32.
Is arranged in the hole 58 so that the optical axis of the light beam from the first cover portion 30a to the first cover portion 30a is parallel to the inner bottom surface 28a.

As shown in FIG. 6, the light incident from the light projector 32 to the light receiver 34 mainly passes through the notch 28 and the inner bottom surface 2.
The direct light 76a travels in parallel with 8a and is directly incident on the light receiver 34. Therefore, if the weft yarn is not present between the light projector 32 and the light receiver 34, the amount of light incident on the light receiver 34 is substantially constant.

However, if the weft yarn 78a is present between the light projector 32 and the light receiver 34, the weft yarn 78a will be positioned between the light projector 32 and the light receiver 32.
Since a part of the so-called direct light 76a which is directly incident on the light receiver 34 through the cutout portion 28 is blocked, the amount of light incident on the light receiver 34 is reduced. Thus, the weft 78a can be detected by confirming that the amount of light incident on the light receiver 34 has decreased by a predetermined amount.

If the weft yarn 78b is present in the cutout portion 28 and at a position apart from between the light projector 32 and the light receiver 34, light that is directed in the cutout portion 28 at an angle with respect to the direct light 76a. 76b irradiates the weft 78b, and the reflected light 7
6c is incident on the light receiver 34. As a result, the light receiver 3
4 is increased, the weft yarn 7 is confirmed by confirming that the amount of incident light on the light receiver 34 is increased by a predetermined amount.
8b can be detected.

An embodiment of a judgment device 80 for judging the presence or absence of wefts using the output signal of the light receiver 34 will be described with reference to FIG.

The determination device 80 receives the output signal S of the photodetector 34 at the terminal 82, and receives the first and second timing signals Ta and Tb at terminals 84a and 84, respectively.
Receive in b. Both timing signals Ta and Tb are signals corresponding to when the main shaft of the loom reaches a predetermined rotation angle,
Output from the loom controller.

The timing signal Ta is the timing before the weft reaches the weft detecting device, and the timing signal T
b is the timing when the weft reaches the weft detection device and the weft insertion is completed. For example, the timing signal Ta
And Tb can be signals when the rotation angles of the main shaft are 100 degrees and 290 degrees, respectively.

The signal S supplied to the terminal 82 is supplied to the amplifier 8
Amplified at 6. The output signal of the amplifier 86 is branched into three branch signals. These branch signals are sent to the reference device 88 which temporarily stores them as reference values, the light cutoff detector 90 which outputs the first electric signal corresponding to the decrease in the amount of light incident on the light receiver, and the light receiver. Is supplied to a light increase detector 92 that outputs a second electric signal corresponding to the increase in the incident light amount of the light.

The reference unit 88 is a circuit that takes in the signal supplied from the amplifier 86 each time the timing signal Ta is supplied and stores it as a reference value, and the stored reference value is supplied with the timing signal Ta. Update every time. However, the reference value may be a preset fixed value. The reference value stored in the storage 88 is supplied to the light blocking detector 90 and the light increase detector 92.

Light cutoff detector 90 and light increase detector 92
Outputs a signal corresponding to the difference between the reference value supplied from the reference unit 88 and the signal supplied from the amplifier each time the timing signal Tb is supplied.

Light cutoff detector 90 and light increase detector 92
Can be a circuit that subtracts the reference value supplied from the reference unit 88 by the signal supplied from the amplifier, or subtracts the signal supplied from the amplifier by the reference value supplied from the reference unit 88. It can also be a circuit. As a result, every time the second timing signal Tb is generated, an analog signal corresponding to the increase / decrease in the amount of light incident on the light receiver is output as the light cutoff detector 90 and the light increase detector 92.
Is output from.

Light cutoff detector 90 and light increase detector 92
Indicates that the timing signal Tb corresponds to the end of weft insertion, that is, the signal when the tip of the weft reaches the sensing area of the photodetector. Is a signal corresponding to the amount of decrease and the amount of increase of the incident light on the light receiver due to.

The output signal of the light-blocking detector 90 corresponds to the amount of decrease in the amount of light received in the light receiver, and the output signal of the light increase detection circuit 92 corresponds to the amount of increase in the amount of light received in the light receiver. Therefore, the output signal of the cutoff detector 90 and the light increase detection circuit 9
The two output signals have opposite polarities. The polarity of the output signal of the light increase detector 92 is inverted by the inverter 94, and the output signal of the inverter 94 is added to the output signal of the light interruption detection circuit 90 in the adder 96.

However, one of the light cutoff detector 90 and the light increase detector 92 is a circuit for subtracting the reference value supplied from the reference device 88 by the signal supplied from the amplifier, and the other is supplied from the amplifier. The inverter 94 may be omitted by forming a circuit that subtracts the signal by the reference value supplied from the reference device 88.

The output signal of the adder 96 is used by the discriminator 98 to judge whether the weft insertion is correct, that is, the presence or absence of the weft. The discriminator 98 compares the output signal of the adder 96 with a threshold value having a predetermined voltage level range, and when the output signal of the adder 96 is within the threshold value, it means that the weft insertion is correct. The signal (the signal with the weft) is output to the terminal 100, and when the output signal of the adder 96 is out of the threshold value, the weft insertion failure signal (the signal without weft) is output to the terminal 100, which means that the weft insertion is not performed correctly. To do.

As described above, in addition to the signal corresponding to the decrease in the amount of light incident on the light receiver by the weft yarn, the signal corresponding to the increase in the amount of light incident on the light receiver due to the reflected light from the weft yarn is used. If the presence or absence of the weft insertion is determined, the detection range of the photodetector is expanded to the pass region of the reflected light that can enter the photodetector, in addition to the pass region of the direct light that enters the photodetector. As a result, the weft detection range is increased without increasing the light receiving area of the light receiver.

Instead of analogically processing the output signal of the light receiver to determine the presence or absence of the weft thread, the output signal of the light receiver may be digitally processed to determine the presence or absence of the weft thread. In this case, for example, the output signal of the amplifier may be converted into a digital signal, and the converted digital signal may be used to determine the presence or absence of the weft.

Further, the signals corresponding to the increase and decrease of the amount of light incident on the photodetector are detected separately, and after adding both signals, instead of judging the presence or absence of the weft, the light cutoff detector 90 and the light increase detector 92 are used. As a comparison processing circuit such as a window comparator or an operational amplifier, one of the comparison processing circuits determines whether or not the amount of light incident on the photoreceiver has decreased by a predetermined amount, and the other comparison processing circuit It may be determined whether or not the amount of light incident on the light receiver has increased by a predetermined amount, and the presence or absence of the weft yarn may be finally determined based on the OR conditions of both determination results.

In the embodiment shown in FIG. 8, the frosted glass 110 is arranged in front of the projector 32. This is because the light from the light projector is dispersed in the cutout portion by utilizing the fact that the frosted glass has a characteristic of scattering light.

In general, as shown in FIG. 9 (A), the light 112 from the light source has a feature that the center 114 of the light source is brightest and the light 114 rapidly decreases outward from the center 114. On the other hand, when the frosted glass is present, FIG.
The light from the light source is dispersed by scattering in the frosted glass as shown in FIG.

In FIG. 10, when the distance from the center 114 (light receiving position) is on the horizontal axis and the light receiving amount is on the vertical axis, the light receiving amount 116 when the frosted glass 110 exists and when the frosted glass does not exist. And the received light amount 118 of.

As is apparent from FIG. 10, the ground glass 1
When 10 is present, the vicinity of the center 114 is darker than that in the case where no frosted glass is present, but the attenuation of light around the center 114 is moderate.

As described above, when the frosted glass 110 is arranged on the light emitting side of the projector 32, the light from the light source is dispersed by the scattering in the frosted glass 110 (the attenuation of the light around it relative to the center is moderate). Since the light is directed to the cutout portion 28 in the state), the amount of light incident on the light receiver becomes more uniform. Therefore, the amount of light blocked by the weft thread does not vary much depending on the position where the weft thread passes. That is, since there is not much difference in the ratio of the amount of light blocked to the total amount of light incident on the light receiver, the gain can be easily set.

In the embodiment of FIG. 8, frosted glass 11
Although 0 is arranged between the projector 32 and the slit 62, the frosted glass 110 may be arranged in the slit 62 or in front of the slit 62.

Between the increase amount (absolute value) of the incident light to the light receiver due to the reflected light from the weft and the decrease amount (absolute value) of the incident light to the light receiver due to the blocking of the light by the weft yarn. If there is a difference that cannot be ignored, the reference signal for determining the presence or absence of wefts based on the decrease amount and the reference signal for determining the presence or absence of wefts based on the increase amount are different values ( It may be set to an absolute value).

The present invention is not limited to the above embodiment. For example, the present invention can be applied not only to the weft detecting device for detecting the weft inserted in the weft inserting device, but also to the weft detecting device in the weft processing device for processing the weft. Further, a light projector may be used in which the light beam generated by the light emitting element is directed by the light guide as described above.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of a weft detection device of the present invention.

2 is an end view taken along line 2-2 of FIG.

3 is an enlarged sectional view taken along line 3-3 of FIG.

FIG. 4 is an enlarged cross-sectional view taken along line 4-4 of FIG.

5 is a cross-sectional view taken along line 5-5 of FIG.

FIG. 6 is an enlarged view of the vicinity of a notch for explaining the relationship between the flying position of the weft and the incident light to the light receiver in the weft detection device of FIG.

FIG. 7 is a block diagram of an electric circuit showing an embodiment of a determination device in the weft detection device of the present invention.

FIG. 8 is an enlarged view of the vicinity of a notch portion in another embodiment of the weft yarn detecting device of the present invention.

9A and 9B are views for explaining a light dispersion state in the embodiment shown in FIG. 8, in which FIG. 9A is an explanatory view in the case where no frosted glass is present, and FIG. It is explanatory drawing of a case.

FIG. 10 is a diagram for explaining the difference in the amount of received light between the presence and absence of frosted glass.

[Explanation of symbols]

20 Weft detection device 28 Notch 32 Floodlight 34 Receiver 76a, 76b Light from the projector 76c Reflected light from weft 78a, 78b weft 110 ground glass

Claims (3)

(57) [Claims] 1. A weft detection device for receiving light projected from a light projector by a light receiver and outputting an electric signal corresponding to the amount of received light from the light receiver, wherein at least first and first output signals from the light receiver are provided. Branching means for branching into two branch signals, first detecting means for outputting a first electric signal corresponding to a decrease in the amount of light incident on the light receiver based on the first branching signal, and Second detection means for outputting a second electric signal corresponding to an increase in the amount of light incident on the light receiver based on the second branch signal, and a weft based on the first and second electric signals A weft detection device of the transmission type, which comprises a determination means for determining the presence or absence of 2. The first electric signal is a signal corresponding to a decrease amount of an incident light amount to the photodetector, and the second electric signal is a signal corresponding to an increase amount of an incident light amount to the photodetector. The weft detection device according to claim 1, wherein the determining means adds the first and second electric signals and then determines the presence or absence of a weft using the added signals. 3. The transmissive weft detection device according to claim 1, further comprising a frosted glass arranged on the light emission side of the light projector.