JPH111848A - Light transmission-type weft detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the subject detector designed to enlarge weft detection range without enlarging the light-receiving area of the receiver. SOLUTION: This detector, comprising a 1st detection means outputting a 1st signal in response to the reduction in the incident light levels to a receiver and a 2nd detection means outputting a 2nd signal in response to the increase in the incident light levels to the receiver, is designed to assess the presence/ absence of a weft based on both the 1st and the 2nd signals by an assessment means. Thereby the detection range of the receiver is expanded to the passable region for the reflected light capable of incidence to the receiver as well as the passable region for the direct light entering the receiver.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art As one of optical weft detecting devices using a light projector and a light receiver facing each other, Japanese Patent Application Laid-Open No.
There is a transmission type weft detecting device described in 42047. This conventional transmission type weft detecting device irradiates light to a flight region of a weft from a light emitter, receives light passing through the flight region by a light receiver, and detects when the weft blocks incident light to the light receiver. The presence or absence of a weft is detected from the decrease in the amount of light received by the light receiver.

However, in a loom, the weft rarely passes outside the original flight area. In such a case, although the weft blocks the light, the cutoff cannot be detected by the light receiver, so that the conventional weft detecting 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 poor even though the weft has reached the non-feed side,
As a result, the loom is stopped.

If the light receiving area of the light receiver is increased to prevent this, the light receiver must be large. For example, even if the amount of received light decreases due to the light blocking described above,
The ratio of the decrease in the amount of light received due to the interruption 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 decreases.

[0005]

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

[0006]

According to the transmission type weft detecting device of the present invention, at least the first and second output signals from the light receiver are output.
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 branch signal; and second branching means A second detection unit that outputs a second electric signal corresponding to an increase in the amount of light incident on the light receiver based on the signal, and a determination that determines the presence or absence of a weft based on the first and second electric signals Means.

Light incident on the light receiver includes so-called direct light that directly enters the light receiver from the light emitter, and so-called reflected light that is incident after being reflected by a weft passing near the outside of the direct light passage area. If the weft is not present in the detection area, the amount of light incident on the light receiver is only direct light and is almost constant.

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

The presence or absence of a weft can be determined by, for example, determining that the weft is present 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 reflected light that can be incident on the light receiver, in addition to the passage area of direct light incident on the light receiver.

According to the present invention, the output signal from the light receiver 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 light receiver is output. In addition to the first detecting means, a second detecting means for outputting a second electric signal corresponding to an increase in the amount of light incident 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 can be increased without increasing the light receiving area of the light receiver.

[0011] The first electric signal is a signal corresponding to the amount of decrease in the amount of light incident on the light receiver, and the second electric signal is a signal corresponding to the amount of increase in the amount of light incident on the light receiver. After adding the first and second signals, the presence / absence of a weft can be determined using the added signal. The addition of the first and second signals can be performed after inverting one of the polarities.

[0012] Preferably, the ground glass is arranged on the light emitting side of the projector. By doing so, the detectable area becomes wider due to the frosted glass feature of scattering light, and the weft can be more accurately detected.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, an embodiment of the structure of a light transmission type weft detecting device 20 shown in FIGS. 1 to 6 will be described. The transmission type weft detecting device 20 is arranged on a loom as an optical type weft detecting device for detecting the inserted weft.

The weft detecting device 20 comprises a first support 24 mounted on a lead holder 22 of a loom, and a plate-shaped and opaque second support fitted to one end of the first support. 26, a transparent cover 30 covering the second support 26 so as to form a notch 28 through which the wefts fly, and a notch 28
, A light projector 32 arranged on one side with respect to
8 and a light receiver 34 arranged on the other side.

The notch 28 has substantially the same shape as the weft guide groove of a reed (not shown). The reed is attached to the lead holder 22. The weft detection device 20 is assembled to the lead holder 22 on the first support 24 so that the notch 28 matches the weft guide groove of the reed.

One end of the first support 24 is connected to a plate 38
And has a recess 40 facing the weave front side.
On the other hand, the other end of the first support 24 is a mounting portion 42 mounted on the lead holder 22, and a projection 44
Is fitted into 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. Is done. The first support 24 has, at one end, a projection 50 protruding inside the upper part of the recess 40, and has a hole 52 at the other end through which a mounting bolt passes.

The second support 26 is provided at the bottom of the recess 40,
It has a back surface, a top surface, and a bottom surface that are substantially the same as the top and bottom surfaces. The second support 26 has a recess 54 in which a front portion thereof is notched, and a protrusion 50 of the first support 24.
And the concave portion 54 is arranged in the concave portion 40 of the first support 24 so that the concave portion 54 is on the weave 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 a pair of elongate holes communicating the holes 58 and 60 with the recesses 54, respectively. Have a portion facing the slits 62 and 64 via the recess 54, and a projection 66 protruding from the recess 54 is provided at the center of the deep bottom of the recess 54. The slits 62 and 64 extend in a direction intersecting with the flight direction of the weft (the depth direction of the notch 28).

The cover 30 includes a first cover part 30a that forms the surface of the notch 28 on the light emitter 32 side, a second cover part 30b that forms the surface of the notch 28 on the light receiver 34 side,
Third cover portion 30c forming the inner bottom surface of cutout portion 28
A fourth cover 30d covering a front surface in the weft flight direction, a fifth cover portion 30e covering a rear surface in the weft 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 third cover portion 30g that covers the lower front surface of the third cover portion, an engagement step portion 30h formed at the lower front end portion of the seventh cover portion, and a through hole 68 formed at the center of the third cover portion 30c. Having.

The first, second and third cover portions 30a,
30b and 30c each have a substantially uniform thickness dimension. Second and third cover portions 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 30h of the cover 30 is engaged with the engagement portion of the first support 24, and the projection 66 of the second support 26 is The first support 24 is fitted into the through hole 68 of the first support 30.
And is bonded to the first support 24. The protrusion 66 prevents the irradiation light from reaching the light receiver 34 through the inside of the third cover 30c.

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

The slits 62 and 64 transmit light having a band-like cross-sectional shape that is long in the depth direction of the notch 28 and short in the flight direction of the weft, respectively.
To guide. This narrows the sensing area of the light receiver 34 in the weft flight direction, so that the presence or absence of the weft can be accurately detected.

A long cylindrical lens extending in the longitudinal direction of the slit 62 may be arranged between the slit 62 and the light projector 32. More specifically, the semi-cylindrical lens is arranged such that the chord direction of the arc-shaped lens is in the width direction of the slit 62 and the convex surface of the lens is on the slit 62 side.
Further, the kamaboko type lens covers the entire light emitting surface of the light projector 32. Therefore, if the semi-cylindrical lens is arranged, the irradiation light from the light projector 32 can be focused on the slit 62.

The inner 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. The first cover part 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 floodlight 32 is a floodlight 32
Are arranged in the hole 58 such that the optical axis of the light beam traveling from the first to the first cover portion 30a is parallel to the inner bottom surface 28a.

As shown in FIG. 6, the light that enters the light receiver 34 from the light projector 32 mainly passes through the notch 28 to the inner bottom surface 2.
Direct light 76a traveling parallel to 8a and directly entering the light receiver 34. Therefore, if the weft does not exist 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 78a exists between the light projector 32 and the light receiver 34, the weft 78a
Since part of the so-called direct light 76a that directly enters the light receiver 34 through the notch 28 is cut off, the amount of light incident on the light receiver 34 decreases. 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 78b is located in the notch 28 and is located at a position deviating from between the light projector 32 and the light receiver 34, the light directed in the notch 28 at an angle to the direct light 76a. 76b irradiates the weft 78b and the reflected light 7
Eventually, the light enters the light receiver 34. Thereby, the light receiver 3
4, the amount of light incident on the light receiver 34 is confirmed to have increased by a predetermined amount.
8b can be detected.

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

The judging device 80 receives the output signal S of the light receiver 34 at a terminal 82, and receives the first and second timing signals Ta and Tb at terminals 84a and 84b, respectively.
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 control device of the loom.

The timing signal Ta is a timing before the weft reaches the weft detecting device.
b is the timing when the weft reaches the weft detecting device and the weft insertion ends. For example, the timing signal Ta
And Tb can be signals when the main shaft rotation angle is 100 degrees and 290 degrees, respectively.

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

The reference unit 88 is a circuit which takes in the signal supplied from the amplifier 86 every time the timing signal Ta is supplied and stores it as a reference value. The stored reference value is supplied with the timing signal Ta. Update every time. However, the reference value may be a fixed value set in advance. The reference value stored in the storage 88 is supplied to the light cutoff 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 for subtracting the reference value supplied from the reference unit 88 by the signal supplied from the amplifier, or subtracting the signal supplied from the amplifier by the reference value supplied from the reference unit 88. Circuit. Thus, every time the second timing signal Tb is generated, an analog signal corresponding to an increase or decrease in the amount of light incident on the light receiver is output from the light cutoff detector 90 and the light increase detector 92.
Output from

Light cutoff detector 90 and light increase detector 92
Since the timing signal Tb is a signal corresponding to the end of weft insertion, that is, a signal when the leading end of the weft reaches the sensing area of the light receiver, the presence or absence of the weft in the sensing area of the light receiver, respectively. Is a signal corresponding to the amount of decrease and increase of the light incident on the light receiver due to the above.

The output signal of the light cutoff detector 90 corresponds to the amount of decrease in the amount of light received by 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 by 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 output signal of the light increase detector 92 is inverted in polarity by the inverter 94, and the output signal of the inverter 94 is added to the output signal of the light cutoff 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 unit 88 by a signal supplied from the amplifier, and the other is supplied from the amplifier. The inverter 94 may be omitted by providing a circuit for subtracting the signal from the reference value supplied from the reference unit 88.

The output signal of the adder 96 is used by the discriminator 98 to determine whether or not weft insertion is performed, that is, whether or not a weft is present. The discriminator 98 compares the output signal of the adder 96 with a threshold having a predetermined voltage level range, and when the output signal of the adder 96 is within the threshold, it means that the weft insertion has been correctly performed. A signal (weft-present signal) is output to the terminal 100, and a weft-insertion failure signal (weft-less signal) is output to the terminal 100 when the output signal of the adder 96 is outside the threshold value, which means that weft insertion was not correctly performed. I 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, the signal corresponding to the increase in the amount of light incident on the light receiver due to the reflected light from the weft is used. If the presence or absence of the weft insertion is determined, the detection range of the light receiver is expanded to the transmission area of reflected light that can be incident on the light receiver, in addition to the transmission area of direct light incident on the light receiver. As a result, the weft detection range is increased without increasing the light receiving area of the light receiver.

Instead of determining the presence or absence of a weft by processing the output signal of the light receiver in an analog manner, the presence or absence of the weft may be determined by digitally processing the output signal of the light receiver. In this case, for example, the output signal of the amplifier may be converted into a digital signal, and the presence or absence of the weft may be determined using the converted digital signal.

Also, signals corresponding to the increase or decrease of the amount of light incident on the light receiver are separately detected, and after adding both signals, instead of judging the presence or absence of a weft, a light cutoff detector 90 and a light increase detector 92 are used. As a comparison, a comparison operation processing circuit such as a window comparator and an operational amplifier is used. In one comparison operation processing circuit, it is determined whether or not the amount of light incident on the light receiver has decreased by a predetermined amount, and in the other comparison operation 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 finally the presence or absence of the weft may be determined based on the OR condition of both determination results.

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

In general, as shown in FIG. 9A, the light 112 of the light source has the characteristic that the center 114 of the light source is the brightest and that the light 112 sharply decreases outward from the center 114. On the other hand, if frosted glass is present, FIG.
The light from the light source is dispersed by scattering in the ground glass as shown in FIG.

FIG. 10 shows a light receiving amount 116 when the ground glass 110 is present and a light receiving amount 116 when the ground glass is not present, where the horizontal axis represents the distance (light receiving position) from the center 114 and the vertical axis represents the light receiving amount. And the received light amount 118 of FIG.

As is apparent from FIG.
When 10 is present, the vicinity of the center 114 becomes darker, but light around the center 114 is attenuated more slowly than when no ground glass is present.

As described above, if the ground glass 110 is arranged on the light emitting side of the light projector 32, the light from the light source is dispersed by scattering in the ground glass 110 (the attenuation of light around the center with respect to the center is moderate. In this state, the light is directed to the notch 28, so that the amount of light incident on the light receiver becomes more uniform. Therefore, the amount of light blocked by the weft does not vary much depending on the position at which the weft passes. That is, since there is not much difference in the ratio of the cutoff light amount to the entire light amount incident on the light receiver, the gain can be easily set.

In the embodiment shown in FIG.
Although 0 is disposed between the light projector 32 and the slit 62, the ground glass 110 may be disposed in the slit 62 or may be disposed in front of the slit 62.

Between the increase (absolute value) of the light incident on the light receiver due to the reflected light from the weft and the decrease (absolute value) of the light incident on the light receiver due to the interruption of the light by the weft. If there is a difference that cannot be ignored, the reference signal for determining the presence or absence of the weft based on the decrease amount and the reference signal for determining the presence or absence of the weft based on the increase amount have different values ( (Absolute value).

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

[Brief description of the drawings]

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

FIG. 2 is an end view taken along line 2-2 of FIG. 1;

FIG. 3 is an enlarged sectional view taken along line 3-3 in FIG. 1;

FIG. 4 is an enlarged sectional view taken along line 4-4 in FIG. 1;

FIG. 5 is a sectional view taken along the line 5-5 in FIG. 3;

FIG. 6 is an enlarged view near a notch for explaining a relationship between a flying position of a weft and light incident on a light receiver in the weft detecting device of FIG. 1;

FIG. 7 is a block diagram of an electric circuit showing one embodiment of a judging device in the weft detecting device of the present invention.

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

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

FIG. 10 is a diagram for explaining a difference in received light amount between a case where frosted glass is present and a case where it is not present;

[Explanation of symbols]

 Reference Signs List 20 weft detecting device 28 notch 32 light emitter 34 light receiver 76a, 76b light from light emitter 76c reflected light from weft 78a, 78b weft 110 ground glass

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI G01V 8/12 G01V 9/04 J

Claims (3)

[Claims] 1. A weft detecting 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 the output signal from the light receiver is at least a first signal and a first signal. 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 branch signal; Second detecting means for outputting a second electric signal corresponding to an increase in the amount of light incident on the light receiver based on a second branch signal; and a weft yarn based on the first and second electric signals A transmission type weft detection device, comprising: a determination unit for determining the presence or absence of a weft. 2. The method according to claim 1, wherein the first electric signal is a signal corresponding to a decrease in the amount of light incident on the light receiver, and the second electric signal is a signal corresponding to an increase in the amount of light incident on the light receiver. 2. The weft detecting device according to claim 1, wherein the judging unit adds the first and second electric signals, and judges the presence or absence of a weft using the added signal. 3. 3. The transmission type weft detecting device according to claim 1, further comprising frosted glass disposed on a light emitting side of the light projector.