JP3523002B2 - Weft detection device for 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 in a fluid jet loom such as an air-jet loom and a water jet loom.

[0002]

2. Description of the Related Art One of the reflection type weft detecting devices for detecting wefts having different light reflectances is disclosed in Japanese Utility Model Publication No. 3-18538. This weft yarn detecting device is provided on the arrival side of the weft yarn and irradiates pulsed light generated by a light projector onto two screens having different light reflectances which are sequentially arranged in the weft inserting direction on the front face side of the reed, and the screen The reflected light from is detected by a light receiver provided for each screen.
The detection signals of both light receivers are added, and the added signal is compared with a threshold value, that is, a reference signal in a comparator to determine the presence or absence of the weft.

In this conventional weft yarn detecting device, the difference between the output signal levels of both photodetectors when the weft yarn is present in the detection area,
Since the presence or absence of the weft is detected by using the difference between the output signal levels of the two photodetectors when the weft is not present in the detection area, it should be used commonly for the detection of multiple types of weft with different light reflectance. Therefore, it is widely used as a device for detecting whether or not weft insertion has been correctly performed in a multicolor fluid jet loom using a plurality of weft yarns having different light reflectances.

However, in this type of reflection type weft yarn detecting device, for example, in the case of the light receiving device on the upstream side in the weft inserting direction, a warp yarn is used, and in the case of the light receiving device on the downstream side in the weft inserting direction, a light receiving device is used. There is a possibility that the light reflected from the yarn adjacent to is incident on the light receiver. Thus, when the reflected light from the yarn adjacent to the light receiver enters the light receiver, the detection of the weft becomes unstable.

From the above, conventionally, the distance between the light receiver and the yarn next to the light receiver is set large so that the reflected light from the yarn adjacent to the light receiver does not enter the light receiver.
Therefore, the length of the weft discard selvage is increased, which is uneconomical.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to shorten the length of the weft discard selvage without destabilizing the weft detection.

[0007]

A weft detection device in a loom according to the present invention comprises a projector for generating light traveling toward a flight path of the weft and a juxtaposed direction of the light with respect to the projector. And a light receiver having a light receiving lens for receiving the light. In the light receiving lens, the size of the light incident part in the weft insertion direction is smaller than the size of the part on the opposite side, and at least a part of the size difference is formed at the end part of the light receiving lens on the side opposite to the projector. ing.

When the size of the light incident part of the light receiving lens in the weft insertion direction is made smaller than the size of the part on the opposite side, in other words, the size of the surface of the light receiving lens facing the flight path side is the light receiving element of the light receiving lens. If it is smaller than the dimension of the side surface, the detection area of the light receiver in the weft insertion direction becomes smaller. Moreover, by forming the dimensional difference at the end of the light receiving lens on the side opposite to the light projector, the detection region is reduced at least on the side opposite to the light projector.
Therefore, even if the distance between the photoreceiver and the yarn adjacent thereto is shortened by such a small amount, the yarn adjacent to the photoreceiver will be outside the detection area of the photoreceiver, and the yarn adjacent to the photoreceiver will be The reflected light of does not enter the light receiver. Moreover, even if it does so, there is no possibility that the light receiving level of the light receiver is lowered.

According to the present invention, as described above, the size of the light incident portion of the light receiving lens in the weft insertion direction is made smaller than the size of the portion on the opposite side, and at least a part of the size difference is caused by the projector of the light receiving lens. Since the end portions on the opposite side are formed, the distance between the light receiver and the yarn adjacent thereto can be shortened, there is no risk of unstable weft detection, and the length of the weft discard ear can be shortened. .

In a preferred embodiment, the light receiving lens is a semi-cylindrical lens having two end faces of an arcuate convex surface, a flat surface and a substantially semicircular shape, and the both end surfaces are spaced in the weft inserting direction. The loom is arranged so that the flat surface is on the side opposite to the flight path and the convex surface is on the flight path side.

The size of the light incident portion of the light receiving lens in the weft insertion direction is set to be equal to that of the light incident portion by, for example, making the end surface on the side opposite to the light projector an angle smaller than 90 degrees with respect to the flat surface. It can be smaller than the size of the opposite site. Further, the size of the light incident portion of the light receiving lens in the weft insertion direction is, for example, by forming a light blocking area at an end of the convex surface of the light receiving lens on the side opposite to the light projector. It can be smaller than the size of the part opposite to the part.

In the preferred embodiment, the light is applied to a pair of screens having different light reflectances. The boundaries of both screens are arranged so as to coincide with the optical axis of the light from the projector, and the light shielding band is arranged at the position where the widthwise center of the shaded portion coincides with the optical axis of the light from the projector. There is. However, the boundaries of both screens are displaced to the side of the screen where the light reflectance is high with respect to the optical axis of the light from the projector, and the center of the light shielding band in the width direction of the shaded part is aligned with the optical axis of the light from the projector. It may be displaced toward the screen having a high reflectance.
In addition, the boundaries of both screens are displaced to the side of the screen with high light reflectance with respect to the optical axis of the light from the projector, and the center of the light shielding band in the width direction of the shaded part matches the optical axis of the light from the projector. You may arrange in the position to do.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1 and 2, a weft detecting device 10 includes a pair of screens 12 and 14 having different light reflectances, a projector 16 for generating light directed to both screens, and a screen. A pair of light receivers 1 and 12 which individually correspond to 12 and 14 and receive reflected light from the corresponding screens.
8 and 20 are included. The pair of screens 12 and 14, the light projector 16 and the two light receivers 18 and 20 have a downstream warp yarn 24 in the weft flying direction, that is, the weft insertion direction 22,
It is arranged between the catch cord 26 for gripping the waste ear of the weft.

The screens 12 and 14 are combined so as to jointly form a long rectangular shape in the flight direction 22, and the boundary 28 between the two forms an optical axis 30 of the projector 16.
Is arranged at the weft arrival side end of a reed (not shown) so as to extend in the direction orthogonal to both the weft inserting direction 22 and the optical axis 30. The screens 12 and 14 are specifically,
It is arranged in the inner bottom portion 32 of the weft flying groove of the reed so as to extend in the weft inserting direction 22 and to move together with the reciprocating reed. In the following description, it is assumed that the reflectance of the screen 12 on the warp 24 side is higher than that of the screen 14 on the catch cord 26 side.

The projector 16 includes a light emitting element 34 using a light emitting diode, a tip lens or a first lens 36 arranged on the front side of the light emitting element, that is, a light sending side, and a light sending side of the first lens. And a second lens 38 disposed. The projector 16 is arranged and supported by an opaque holder 40. The light projector 16 and the later-described light receivers 18 and 20 are provided in a lead holder (not shown).

The first lens 36 is a convex lens for condensing light which prevents diffusion of light generated from the light emitting point 34a of the light emitting element 34. In the illustrated example, the first lens 36 is a hemispherical convex lens, and is arranged in the holder 40 such that the flat surface side thereof is the light emitting element 34 side and the spherical surface side thereof is the second lens side. . The light emitting element 34 and the first lens 36 are coaxially combined so that the light emitting point 34 a of the light emitting element 34 is in the center of the flat surface of the first lens 36.

The second lens 38 is a semi-cylindrical lens that converts the light emitted from the first lens 36 into a band-shaped cross section. In the illustrated example, in the second lens 38, the longitudinal direction is the weft inserting direction 22, the flat surface side is the first lens 36 side, and the arc surface side, that is, the convex surface side is the screens 12, 14 side. It is arranged in an opaque holder 40 and is coaxially combined with the first lens 36. Therefore, a long strip of light in the weft insertion direction 22 is projected on the screens 12 and 14.

The light receiver 18 collects and collects the reflected light from the corresponding screen 12, that is, a light receiving lens 42, and receives the light collected by the light receiving lens to generate an electric signal corresponding to the amount of light received. And a light receiving element 44 such as a phototransistor.

The light-receiving lens 42 is a semi-cylindrical lens that collects the band-shaped reflected light from the screen 12 on the light-receiving element 44, and the arc surface, that is, the convex surface side is the screen 12 side and the flat surface is the screen 12. The holder 40 is arranged so as to be on the opposite side. Light receiving element 44
Is provided on the flat surface of the light receiving lens 42. The light-receiving lens 42 has a surface 46 on the side opposite to the projector 16 at 90 degrees with respect to the flat surface 48 so that the dimension in the weft insertion direction 22 gradually decreases from the light-receiving element 44 side toward the incident side of reflected light. It is an inclined surface with a smaller angle θ 1. The surface 50 on the side of the projector 16 is a surface that is approximately 90 degrees with respect to the flat surface 48.

The dimension L1 of the light incident portion of the light receiving lens 42 in the weft insertion direction is the dimension L2 of the portion on the light receiving element 44 side.
Therefore, the size is reduced by L3. In the present embodiment, the light receiving lens 42 has the inclination angle θ 1 with respect to the flat surface 48 only for the surface 46 on the side opposite to the projector 16.
Therefore, the dimensional difference L3 between the light incident portion and the portion on the side of the light receiving element 44 is formed at the end of the light receiving lens 42 opposite to the light projector 16.

The angle θ 1 is selected so that the edge of the corresponding screen 12 is in the visual field of the light receiving lens 42, but the warp 24 is not in the visual field of the light receiving lens 42. Therefore, the angle of the surface 46 with respect to the flat surface 48 may be an angle θ 2 at which the edge of the corresponding screen 12 is the end of the visual field of the light receiving lens 42. It should be noted that not only the surface 46 but also the surface 50 of the light receiver 42 on the projector 16 side may have an inclination angle smaller than 90 degrees with respect to the flat surface 48. At this time, the dimension L3 which is a part of the dimension difference is formed at the end portion of the light receiving lens 42 on the side opposite to the projector 16.

The light receiver 20 also receives and collects the reflected light from the corresponding screen 12 and the light receiving lens 52, and receives the light collected by the light receiving lens to generate an electric signal corresponding to the received light amount. And a light receiving element 54 that operates. The light-receiving lens 52 and the light-receiving element 54 have the same functions as the light-receiving lens 42 and the light-receiving element 44 of the light receiver 18, respectively, are formed in the same manner as those, and are arranged similarly to them. Therefore, the light receiving lens 52 is provided with the surface 56 on the side opposite to the light projector 16.
Is an angle θ1 or θ smaller than 90 degrees with respect to the flat surface 58
2 is an inclined surface, and the surface 60 on the side of the projector 16 is
Is approximately 90 degrees with respect to the flat surface 58.

In the weft detecting device 10, the light emitting element 34
The light generated in the screen 12 and 14 is made into a band-like light long in the weft insertion direction 22 of the weft by the lenses 36 and 38.
And is reflected by the screens 12 and 14 to enter the photodetectors 18 and 20 as band-shaped light.

In the weft detecting device 10, the surfaces 46 and 56 of the light receiving lenses 42 and 52 are flat surfaces 4 respectively.
Angles θ1 or θ less than 90 degrees for 8 and 58
2, the dimension L1 of the light incident part of the light receiving lenses 42 and 52 in the weft insertion direction is flat.
The dimension L3 is smaller than the dimension L2 of the portion on the side of, and the warp yarn 24 and the catch cord 26 are respectively attached to the light receiver 18
And 20 out of view.

According to the weft detecting device 10, the light receiving lens 4
By making the size L1 of the light incident part of 2, 52 smaller than the size L2 of the part on the side of the light receiving elements 44, 54 by the size L3, the condensing range of the light receiving lens 42 on the warp 24 side is
Further, the catching range of the light receiving lens 52 is set to the catch code 26.
Each side can be as narrow as that. Therefore, the distance between the light receivers 18 and 20 and the yarns 24 and 26 adjacent thereto is shortened by the length of the position of the inner bottom portion 32 of the weft flying groove of the reed which is narrowed in the weft inserting direction. Even
The yarns 24 and 26 adjacent to the photodetectors 18 and 20 are outside the detection area of the photodetectors 18 and 20, and
The reflected light from the yarn adjacent to 0 does not enter the light receivers 18 and 20. Moreover, even if it does so, there is no possibility that the light receiving levels of the light receivers 18 and 20 are lowered. Those results,
There is no risk that the weft yarn detection becomes unstable, and the length of the weft discard ear can be shortened.

Instead of making the surfaces 46 and 56 of the light receiving lenses 42 and 52 inclined with respect to the flat surfaces 48 and 58 at an angle of less than 90 degrees, the condenser lens shown in FIG.
2, the surface 64 on the side opposite to the light projector is a surface of about 90 degrees with respect to the flat surface 66, and the crescent-shaped light blocking area 68 for blocking the passage of light is formed on the arc surface of the light receiving lens 62. The light blocking area 68 reduces the dimension L1 of the light incident portion of the light receiving lens 62 in the weft insertion direction by a dimension L3 smaller than the dimension L2 of the portion on the side of the flat surface 64 so that the adjacent yarns are out of the field of view of the light receiver. May be. In the light receiving lens 62, the surface 69 on the side of the projector 16 is a surface that is approximately 90 degrees with respect to the flat surface 66.

As in the weft detecting device 70 shown in FIG. 4, the light shielding band 72 may be formed on the light transmitting side of the second lens 38. The light-shielding band 72 is formed of a member that blocks passage of light, for example, a light-shielding film made of black paint, and the center in the width direction (flying direction 22) is aligned with the optical axis 30. The second lens 3 so that it is in the vicinity of 30
8 is formed on the convex surface. In the example shown in FIG. 4, the light shielding band 72 extends in an arc shape on the convex surface of the second lens 38 in the circumferential direction. For this reason, the center of the rectangular shadow portion 74 in the width direction is formed near the boundary 28 between the screens 12 and 14. This shaded portion 74 is
It extends through the border 28 and across the screen 14.

The detection range, that is, the detection area of the light receivers 18 and 20 is indicated by alternate long and short dash lines 76 and 78 in FIG. 4, respectively.
The shaded area 74, shown as a triangular area defined by
Is set so that it enters one end (end on the side of the projector 16) of the detection area, and the screen edge opposite to the corresponding screen boundary 28 enters the other end. For this reason, there is no possibility that each of the light receivers 18 and 20 will detect the reflected light from the screen on the side that does not correspond to this, and therefore the conventional device that also receives the reflected light from the screen that does not correspond to each of the light receivers 18 and 20. In contrast, when the weft yarn is not present in the detection area, the difference in the amount of light received by both light receivers, that is, the difference in the amount of incident light, is extremely large corresponding to the difference in the reflectance of the screens 12 and 14.

When both screens may vibrate and displace in the weft insertion direction with respect to the projector and both light receivers due to the vibration of the reed blades, the detection areas of the light receivers 18 and 20 include at least a part of the shaded portion 74. The range including, for example, the boundary 28 may be set so as to substantially coincide with the edge portion on the projector 16 side. In this case, for example, the surface 5 of the second lenses 42 and 52 on the projector 16 side is set so that the limit position of the detection area on the projector 16 side is the center in the width direction of the shaded portion 74.
Each of 0 and 60 may be an inclined surface having an angle smaller than 90 degrees with respect to the flat surface, as indicated by a chain double-dashed line in FIG.

In this way, the screens 12 and 14 are
Is oscillated and displaced with respect to the light receivers 18 and 20 in the weft insertion direction within a range of half the width L1 of the shaded portion 74 or less.
The reflected light from the unsupported screen does not enter each light receiver. In addition, the screens 18 and 20 are the light receivers 18 and 20.
On the other hand, even if the displacement in the weft inserting direction is within the range of L1 / 2 or more,
Receivers 18 and 20 for reflected light from incompatible screens
The amount of light incident on is significantly smaller than that of the conventional device. Therefore, the difference in the amount of light incident on both light receivers when the weft yarn is not present in the detection area is larger than that in the conventional device. Of course, the shaded portion 74 is always located at a fixed position regardless of the vibration displacement of the screens 12 and 14.

The detection areas of the photo detectors 18 and 20 are shown in FIG.
It is possible to prevent reflected light from an unsupported screen from entering the angular receiver simply by setting as shown by the one-dot chain lines 76 and 78 or the two-dot chain line. However, the detection areas of the light receivers 18 and 20 are located in a range including at least a part of the shaded area, for example, on the screens 12 and 14 to which the edges of the detection areas of the light receivers 18 and 20 on the projector 16 side correspond. It may be set so as to include a part of the shaded portion 74. By doing so, even if both screens 12 and 14 are largely displaced with respect to the light receivers 18 and 20 in the weft inserting direction, it is possible to prevent the reflected light from the incompatible screens from entering the light receivers 18 and 20. it can.

The width L1 of the shaded portion 74 is 4.04 mm,
The length dimension of one side of the square light emitting point 34a of the light emitting element 34 is 200 μm, and the second lenses 42 and 48 and the screen 1 are
When the distance L2 from 2, 2 is 10 mm, the angles θ1, θ2, θ3, θ4, θ5 and θ6 in FIGS. 1 and 4 are 72 degrees, 66 degrees, 59 degrees and 66 degrees, respectively.
The degrees can be 63 degrees and 55 degrees.

In the embodiment shown in FIG. 4, the boundary 28 between the screens 12 and 14 is moved to an appropriate value, for example, 1 mm (0 mm) toward the side of the photodetector 18 that receives the reflected light from the screen 12 having a high light reflectance. Both screens 12 and 14 may be arranged so as to be offset from each other on the reed 28 so as to be shifted by 0.5 to 1.5 mm. Instead of this, the light shielding band 72 is arranged so that the center in the width direction of the shaded portion 74 is shifted from the optical axis 30 toward the screen 12 having a high light reflectance by an appropriate value. To the appropriate value,
For example, it may be shifted by 1 mm.

FIG. 5 shows an embodiment of an electric circuit of the weft detecting device 10. The light receiving element 34 of the light projector 16 is driven by a rectangular wave drive pulse having a constant frequency f0. Therefore, light is projected from the projector 16 to a screen (not shown) at a cycle of 1 / f0, and reflected light from the screen is incident on the photodetectors 18 and 20 at a cycle of 1 / f0. The drive pulse is generated in a drive circuit (not shown).

The detection signals of the photo detectors 18 and 20 are detected and amplified in the detection / amplification circuits 80 and 82, respectively. The output signals of the detection and amplification circuits 80 and 82 are added in the adder 84. The summed signal is amplified by the voltage level in the amplifier 86, and then the comparator 88.
Is supplied to. The comparator 88 compares the voltage level of the addition signal with the reference signal, that is, the threshold level set in the threshold setting unit 90, and outputs a signal 92 indicating whether the former is higher than the latter.

The output signal 92 is used as a signal in a determination circuit (not shown) for determining whether or not a weft yarn is present at a predetermined timing when weft insertion is completed.
The above determination in the determination circuit can be performed, for example, by such a method that when the former is higher than the latter, the weft exists in the detection region, and when the former is lower than the latter, the weft does not exist in the detection region.

The detection / amplification circuits 80 and 82 are actually fair 3-1.
As described in detail in Japanese Patent No. 8538, the input signals from the corresponding photodetectors 18 and 20 are detected and the voltage level of the obtained signal is amplified. For example, screen 1
When the reflectance of 2 is set higher than the reflectance of the screen 14, the detection amplification circuit 82 amplifies the detected signal as it is, while the detection amplification circuit 80 inverts the detected signal and then amplifies it. To do. Detection amplification circuit 80, 82
The output signals from the adder 84 are added by the adder 84, and the amplifier 86
Is amplified by and is output to the comparator 88.

The present invention is not limited to the above embodiment. For example, the present invention can be applied not only to a weft yarn detector using two screens and two light receivers, but also to a weft yarn detector using one screen and one light receiver. Further, the light projector may be provided with only one of the lenses 32 and 34, or may be provided with a guide for guiding the band-shaped light beam.

[Brief description of drawings]

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

FIG. 2 is a perspective view showing an embodiment of a light receiving lens of a light projector.

FIG. 3 is a perspective view showing another embodiment of the light receiving lens of the projector.

FIG. 4 is a plan view showing another embodiment of the weft detection device of the present invention.

5 is a block diagram showing an example of an electric circuit in the weft detection device of FIG. 1. FIG.

[Explanation of symbols]

10,70 Weft detection device 12,14 screen 16 Floodlight 18,20 Receiver 22 Weft insertion direction 24 warp 26 Catch code 28 screen boundaries 30 optical axes 34 Light emitting element 36, 38 First and second lenses 40 holder 40 shaded area 42, 52, 62 Light receiving lens 44,54 Light receiving element 46,56,64 Light receiving lens surface 48,58,66 Flat surface of light receiving lens 68 Light blocking area

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-61-241628 (JP, A) Actual development 63-97255 (JP, U) Actual public Kohei 3-18538 (JP, Y2) (58) Survey Field (Int.Cl. ⁷ , DB name) D03D 51/34 101

Claims (4)

(57) [Claims] 1. A light projector for generating light traveling to a flight path of a weft, and a light receiver provided in parallel with the light projector in a weft insertion direction and provided with a light receiving lens for receiving reflected light of the light, In the light receiving lens, the size of the light incident part in the weft insertion direction is smaller than the size of the part on the side opposite to the light incident part, and each end of the light incident part in the weft insertion direction is defined as the light incident part. Each angle formed inside the light receiving lens with respect to the opposite side portion of each straight line connected to each corresponding end portion of the opposite side portion is such that the straight line on the projector side is more than the straight line on the anti-projector side. A weft detection device for a loom, which is also large. 2. The light-receiving lens is a semi-cylindrical lens having an arc-shaped convex surface, a flat surface, and two substantially semicircular end surfaces, and the both end surfaces are spaced in the weft insertion direction. The weft detecting device according to claim 1, wherein the weft detecting device is arranged on the loom so that the side opposite to the flight path and the convex surface side are on the flight path side. 3. The weft detecting device according to claim 2, wherein the end surface on the side opposite to the light projector has an angle smaller than 90 degrees with respect to the flat surface. 4. The weft detection device according to claim 2, wherein the light receiving lens has a light blocking region at an end of the convex surface on a side opposite to the light projector.