JPH10251941A - Weft detector for air jet loom - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a weft detector which is improved in stability by controlling deterioration in S/N ratio resulting from differences between wefts in passing position and also by controlling unnecessary disturbing light from entering the detector to secure a high S/N ratio. SOLUTION: This weft detector is equipped with a projector 32 and light receiver 34 facing each other across a weft passage, which are respectively supported by a first holder 24 and second holder 26, wherein the first holder 24 is equipped on the weft passage side with a slit 62 extending to intersect with the weft passage, and the second holder 26 is equipped with a slit 64 on the weft passage side extending in parallel to the slit 62. This design allows a luminous flux of a virtually constant width in the slit width direction to be received, controlling S/N ratio from being deteriorated even when the wefts pass at different positions, and also minimizing the luminous flux with which the light receiver 34 is not irradiated so as to control reflection-caused disturbing light, with the result that the wefts can be detected more stably.

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 an air jet loom, and more particularly to an optical weft detecting device suitable for detecting a weft inserted.

[0002]

2. Description of the Related Art One of optical type weft detecting devices is disclosed in Japanese Patent Publication No. 63-19196.
This conventional weft detection device is provided adjacent to a deformed wing in an air jet loom, and detects a weft flying on a weft flight path formed by a deformed reed wing. Japanese Patent Publication No. 2517471, which is described as a reference in the gazette, includes a projecting device, a light receiving device, a projecting device, and a holder for the light receiving device, in which a weft detecting device is arranged to face each other. Has a dome-shaped lens and a dome-shaped window in front of the light receiver.

[0003]

In such a conventional technique, a diffused light beam from a light projector is focused by a dome-shaped lens and then radiated to a light receiver via a weft flight path. At this time, the squeezed light beam is irradiated so as to include at least the weft flight region 85 (FIG. 13), and the light receiver receives at least a circular light beam 80 having a diameter corresponding to the weft flight region (FIG. 13). 12 dash-dot line).

For this reason, the range length (length in the flight direction of the weft) of the light beam blocked by the weft differs depending on the difference in the passing position of the weft in the flight area. The / N ratio deteriorates, and there is a problem that stable weft detection cannot be performed in the entire detection range.

More specifically, as shown in FIG. 12, when a weft passes near the center of a circular light beam in a certain weft insertion, the light beam is blocked over the longest range (see reference numeral 83). When passing through a position distant from the center, the length becomes short (see reference numeral 82), and a good S / N ratio cannot be obtained.

Further, although the light beam from the light projector is converged by the lens, the light beam is directed toward the weft flight path while diffusing, so that there are light beams that are not directly radiated to the light receiver, and they are reflected by reeds, fluff, etc. The light is emitted to the light receiver as disturbance light. As a result, a high S / N ratio cannot be obtained even when weft yarns are present, resulting in a problem that the detection of weft yarns becomes unstable.

[0007] The present invention is based on the difference in S
It is an object of the present invention to stabilize the weft detection by suppressing deterioration of the / N ratio and suppressing a penetration of unnecessary disturbance light to obtain a high S / N ratio.

[0008]

A weft detecting device according to the present invention comprises a light emitter and a light receiver which are opposed to each other with a weft flight path interposed therebetween, and a holder for the light projector, which is on the side of the weft flight path of the light projector. A first holder having a slit extending in a direction intersecting with the flight direction of the weft, and a holder of the light receiver, wherein the holder extends in the same direction as the slit on the weft flight path side of the light receiver. A second holder having a slit.

According to the structure of the present invention, the light beam received by the light receiver via the slit has a substantially constant width in the weft insertion direction in a direction orthogonal to the weft insertion direction. Also, the length of the weft blocking the light beam is almost constant, and the S / N ratio is hardly deteriorated. Further, since the light projector irradiates the weft flight path through the slit, the light flux not directly irradiating the light receiver is reduced, and disturbance light due to reflection is suppressed accordingly, so that a high S / N ratio can be obtained.

[0010] If the slits of the first holder and the second holder are extended in a direction perpendicular to the flight direction of the weft, the required length of the slit is minimized.

It is preferable that the slit of at least the second holder is formed from a continuous opening and that the width at both ends is larger than the width at the center in the extending direction of the slit. With such a configuration, the luminous intensity of the received light beam becomes substantially uniform in the extending direction of the slit, and the luminous intensity of the light beam due to the difference in the passing position of the weft is increased.
/ N ratio variation can be suppressed.

Further, the slit of the second holder is formed by a large number of holes, and is formed such that the formation density of the holes at both ends is higher than the formation density of the holes at the center in the extending direction of the slit. You can also. Even with such a configuration, the variation in the S / N ratio can be suppressed for the same reason as described above.

[0013] The first holder is provided between the slit and the projector, and has a semi-circular lens having a flat surface and substantially semicircular both end surfaces so that the both end surfaces are spaced from each other in the extending direction of the slit. can do. According to such a configuration, the luminous flux from the light projector is narrowed in the width direction of the slit, and light with a high luminous intensity can be irradiated, so that a higher S / N ratio is achieved.
Ratio can be obtained.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

The transmission type weft detecting device 20 comprises a first support 24 mounted on a lead holder 22 of an air jet loom, and a plate-shaped and opaque fitting fitted to one end of the first support. A second support 26, a transparent cover 30 that covers the second support 26 so as to form a cutout 28 where the wefts fly, and a light projector 32 arranged on one side of the cutout 28. And a light receiver 34 arranged on the other side with respect to the cutout 28.

A reed (not shown) made of a modified reed wing having a weft guide groove defining a weft flight path is attached to the lead holder 22. Notch 28 of weft detecting device 20
Has the same shape as the weft guide groove of the modified reed dent. The weft detection device 20 is provided such that the notch 28 matches the weft guide groove of the reed.

One end of the first support 24 is formed as a plate-shaped portion 38, has a width (for example, 10 mm) sufficiently larger than the interval between the reeds, and has a recess 40 facing the front side of the weaving. On the other hand, the other end of the first support 24 is a mounting part 42 mounted on the lead holder 22, and the convex part 44 is fitted into the concave part of the lead holder 22, and the inclined convex part 46 is formed. 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, and is assembled to the lead holder 22. One end of the first support 24 has a recess 40
Has a projection 50 protruding inwardly at the top, and a hole 52 at the other end through which a mounting bolt passes.

The second support 26 has rear and upper and lower surfaces substantially the same as the inner bottom and upper and lower surfaces of the recess 40. Second
As shown in FIG. 5, the support 26 has a recess 54 with a front portion cut out, and a recess 56 fitted with the projection 50 of the first support 24. Then, the first support 24 is opened so that the recess 54 opens to the weave front side.
Is mounted in the recess 40.

Further, the second support 26 has a pair of vertically extending holes 58 and 60 for accommodating the light projector 32 and the light receiver 34 and a pair of holes 58 and 60 respectively.
4 has a pair of slits 62 and 64 communicating with the slit 4. Therefore, in the present embodiment, the second support 26 constitutes the first holder and the second holder in the present invention. As shown in FIGS. 3 to 5, the second support 26 has a projection 66 projecting into the recess 54 at the center of the deep bottom of the recess 54. The slits 62 and 64 will be described later in detail.

The cover 30 includes a first cover portion 30a that forms the surface of the notch 28 on the light emitter 32 side, a second cover portion 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 the rear surface of the second support 26 in the weft flight direction, and a fifth cover portion 30e covering the front surface of the weft in the flight direction.
A sixth cover 30f covering the upper front surface of the second support 26, a seventh cover 30g covering the lower front of the second support 26, and a lower front end of the seventh cover 30g. And a through hole 68 formed at the center of the third cover 30c. The angle formed by the second cover 30b and the third cover 30c 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 engaging step 30h of the cover 30 is engaged with the engaging portion of the first support 24, and the through hole 68 of the cover 30 is provided in the second support. 2
6 are fitted in the recesses of the first support 24 and fitted to the first support 24 in a state of fitting with the protrusions 66 of the sixth support. The protrusion 66 prevents the irradiation light from reaching the light receiver 34 through the inside of the third cover 30c.

The light projector 32 and the light receiver 34 are arranged in holes 58 and 60, respectively, and are connected to a connector 70 provided at the lower end of the first support 24 by electric wires 72 and 74. As shown in FIG. 9, a long semi-cylindrical lens 81 extending in the extending direction of the slit 62, in other words, extending in the longitudinal direction of the slit 62, may be arranged between the slit 62 and the projector 32. More specifically, the semi-cylindrical lens 81 is arranged such that the arc-shaped chord direction is orthogonal to the longitudinal direction of the slit 62 and the convex surface of the lens faces the slit 62 side. In addition, the kamaboko lens 81
Covers the entire light emitting surface of the light projector 32. By arranging the semi-cylindrical lens 81 in this way, the irradiation light from the light projector 32 can be focused on the slit 62.

As shown in FIG.
a is a flat surface, and the first cover portion 30a of the cover 30
Are formed in a plate shape having the same thickness dimension. The first cover portion 30a is inclined at a predetermined angle with respect to the inner bottom surface 28a so as to be higher toward the inner bottom surface 28a. The light projector 32 is disposed in the hole 58 such that the optical axis of the irradiation light from the light projector 32 toward the first cover 30a is parallel to the rear bottom surface 28a.

The slits 62 and 64 extend in a direction intersecting with the weft flight direction (for example, a direction forming 90 °), and are arranged to face each other as shown in FIGS. The slits 62, 64 are formed from rectangular openings as shown in FIGS. 3, 4, and 6, each having a width of 0.5 mm,
It has a length of 4 mm. Also, the slit 62
Is formed at a position where the center (the intersection of the diagonal lines of the rectangle) coincides with the light emitting point of the light projector 32.

The light beam from the light projector 32 is limited to a light beam having an irradiation angle θ1 (for example, 18 °) due to the presence of the slit 62 and is irradiated to the notch 28 (FIG. 8). Then, due to the presence of the slit 64, only the part of the irradiation light that is close to parallel light in the width direction of the slit reaches the light receiver 34. Therefore, as shown in FIG. 12, in the steady state, the light beam 84 having the shape of the slit 64 is received by the light receiver 34. At this time, the irradiation angle θ2 of the light beam that has passed through the slit 62 has a value (for example, 106 °) equal to the half-value angle of the light-emitting diode constituting the light projector 32.

Therefore, even if the passing position of the weft is different for each pick, the length of the cut off by the weft is almost the same. Does not vary greatly.

It should be noted that a slit 62 is provided from the front of the projector 32.
The longer the distance L to the distance, the smaller the irradiation angles θ1 and θ2 of the light beam passing through the slit 62 can be. For example, when the distance L is set to 3 mm, the irradiation angle θ1 of the light beam that has passed through the slit 62 is 9 °, so that the irradiation light traveling toward the notch 28 is closer to parallel light in the width direction of the slit. In addition, the irradiation angle θ2 becomes as small as 62 °, and unnecessary irradiation light passing through the slit 62 can be limited accordingly, so that the occurrence of disturbance light due to reflection can be reduced.

Each of the slits 62 and 64 has a larger width at both ends than the width (0.5 mm) at the center in the longitudinal direction of the slit as shown in FIG. So that, for example, 0.8 mm
May be formed. The irradiation light decreases in luminous intensity as the distance from the light emitting point position 86 in the longitudinal direction of the slit decreases and becomes lowest at the end. Therefore, if the width of both ends of the slit is made larger than the center, the luminous flux passing through the slit is increased. Of the luminous intensity in the longitudinal direction of the slit can be reduced. Therefore, a decrease in the S / N ratio can be further suppressed.

Further, since the longitudinal sides of the slits 62 and 64 are curved and the width gradually increases from the center to the end, the luminous intensity in the longitudinal direction of the slit becomes uniform. I have. Note that such a shape is
This is preferentially applied to the slit 64 on the side, and the slit 62 on the side of the projector 32 at this time may have a rectangular shape with a width of 0.8 mm.

The slits 62 and 64 may be formed of a group of a large number of holes instead of being formed from a continuous opening such as a rectangular opening. At this time, as shown in FIG. 11, if the formation density is set to be higher at both ends than at the center of the slit, it is more preferable that the formation density is gradually increased from the center to the end. If the height is gradually increased, the same effect as in the embodiment shown in FIG. 10 can be obtained.

In the embodiment described above, the slits 62,
Although the longitudinal dimensions of the optical receivers 64 are the same,
The length in the longitudinal direction of the slit 64 on the side may be increased to, for example, 6 mm. At this time, the slit 64 is
2mm (longitudinal dimension 4mm) on both sides 1mm
Are arranged so as to be longer each time.

[0032]

According to the present invention, a light beam having a substantially uniform width in the width direction of the slit can be received in a steady state due to the presence of the slit, so that the S / N ratio is deteriorated even when the weft passing position is different. In addition, since the amount of light that is not directly applied to the light receiver is reduced and disturbance light due to reflection is suppressed, stable weft detection can be performed as a result.

[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 a partially enlarged view of the weft detecting device of FIG. 1;

FIG. 7 is an enlarged sectional view taken along line 2-2 of FIG. 1;

FIG. 8 is a partial sectional view taken along line 6-6 in FIG. 5;

FIG. 9 is a view showing a state in which a kamaboko lens is mounted.

FIG. 10 is a diagram showing another embodiment relating to the shape of the slit.

FIG. 11 is a view showing another embodiment relating to the shape of the slit.

FIG. 12 is a diagram showing a conventional light receiving state and a light receiving state of the present invention.

[Description of Signs] 20 Weft detector 24 First support 26 Second support 32 Projector 34 Receiver 62, 64 Slit

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[Procedure amendment]

[Submission date] June 3, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Brief description of drawings

[Correction method] Change

[Correction contents]

[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 a sectional view taken along line 2-2 in FIG.

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 a partially enlarged view of the weft detecting device of FIG. 1;

FIG. 7 is an enlarged sectional view taken along line 2-2 of FIG. 1;

FIG. 8 is a partial sectional view taken along line 6-6 in FIG. 5;

FIG. 9 is a view showing a state in which a kamaboko lens is mounted.

FIG. 10 is a diagram showing another embodiment relating to the shape of the slit.

FIG. 11 is a view showing another embodiment relating to the shape of the slit.

FIG. 12 is a diagram showing a conventional light receiving state and a light receiving state of the present invention.

FIG. 13 is a diagram showing an irradiation state.

[Description of Signs] 20 Weft detector 24 First support 26 Second support 32 Projector 34 Receiver 62, 64 Slit

Claims (5)

[Claims] 1. A light projecting device and a light receiving device arranged opposite to each other with a weft running path interposed therebetween, and a holder of the light projecting device, wherein the light projecting device extends on a side of the light projecting device in a direction intersecting a weft flight direction. An air jet comprising: a first holder having a slit; and a second holder having a slit extending in the same direction as the slit on a side of the weft running path of the light receiver, the first holder having the slit. Room weft detector. 2. The weft detecting device for an air jet loom according to claim 1, wherein each slit of said first holder and said second holder extends in a direction orthogonal to a flight direction of the weft. 3. The slit of at least the second holder is formed of a continuous opening, and the width at both ends is larger than the width at the center in the extending direction of the slit. Or the weft detection device for an air jet loom according to 2. 4. The slit of at least the second holder is formed by a large number of holes, and the density of holes formed at both ends is greater than the density of holes formed at the center in the extending direction of the slit. Or the weft detection device for an air jet loom according to 2. 5. The first holder is provided with a semi-circular lens having a flat surface and substantially semicircular both end surfaces between a slit and a projector so that the both end surfaces are spaced from each other in a direction in which the slit extends. The weft detecting device for an air jet loom according to any one of claims 1 to 4, which is disposed.