JPH0345984Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field of the Invention The present invention relates to a thread sensor for a loom, and particularly relates to a means for expanding the thread detection area and preventing it from being affected by fluff.

Prior Art For example, Japanese Patent Application Laid-Open No. 57-5947 discloses an optical weft filler in which a cylinder lens is disposed in front of a light-emitting element and a light-receiving element.
This cylinder lens is arranged substantially parallel to the weft thread during weft insertion. For this reason,
The light projection efficiency and light receiving efficiency for the weft yarn are good, and this is advantageous in that no weft yarn is overlooked.

However, when such a cylinder lens is used, a space corresponding to the thickness is required at the installation position, so it can be used for other purposes, such as a defective yarn removal device that detects when a weft yarn is guided into a narrow space. In applications such as this, it becomes difficult to incorporate the thread, and the thread detection area also decreases accordingly.

In addition, as stated in the above publication, such thread sensors are always susceptible to a decrease in sensitivity due to fluff, so it is important to have a structure that prevents fluff from adhering and is easy to clean. There must be.

Purpose of the invention Therefore, the purpose of the invention is to
It is easy to install, expands the thread detection area, and has a structure that prevents air fluff from adhering.
Moreover, it is to be possible to easily clean when fluff is attached.

Therefore, the present invention has a holder having a recess provided near the yarn detection area, and a light emitting element and a light receiving element are mounted in the recess so as to optically face each other, and a light shielding part is provided between them. In addition to preventing direct incidence of light from the light-emitting element to the light-receiving element, by covering at least the light-emitting element with a light-transmitting material, the light-emitting surface is formed as a smooth surface. By refraction of light between the light receiving element and the air, the detection range of the thread is expanded in front of the light receiving element. In this way, the light-transmitting body protects the light-emitting element and, if necessary, the light-receiving element, has a shape that is easy to clean, and at the same time refracts the light emitted from the light-emitting element at the boundary surface, so that it This makes thread detection possible. In a preferred embodiment, the transparent body is formed integrally with the holder by filling a recessed portion of the holder.

Configuration of the invention First, FIG. 1 shows a thread sensor 1 of the invention. The thread sensor 1 includes, for example, two light emitting elements 4, a light receiving element 5, and a light transmitting body 6 in a recess 3 at the edge of the holder 2.

The holder 2 is formed, for example, in a rectangular shape by a plastic plate or a metal plate, and
A W-shaped depression 3 is integrally formed at one end edge. The two light-emitting elements 4 are, for example, light-emitting diodes, and a thread detection area 8 is formed on the inclined surface 7 of the recess 3.
is fixed toward the center of the The light-receiving element 5 is, for example, a phototransistor, and is fixed at the center of the protruding surface 9 of the recess 3 toward the center of the yarn detection area 8, similarly to the light-emitting element 4. and,
Both shoulder portions of this protruding surface 9 form light shielding portions 10 for blocking direct incident light from both light emitting elements 4 to light receiving element 5 . The transparent body 6 is
For example, it is made of transparent plastic, and is formed to have the same thickness as the holder 2 by filling the recess 3, and has a smooth front surface that is the same as the outline of the holder 2. As a result, the two light emitting elements 4 and the light receiving element 5 are completely covered with the transparent body 6. Of course, this transparent body 6 is a medium with a higher refractive index than air.

Note that the holder 2 is integrally formed with two long holes 2a for attachment.

Effect of the invention FIG. 2 shows an example in which the yarn sensor 1 described above is incorporated into an incompletely wefted yarn removing device 11. This defective yarn removing device 11 was developed in the applicant's patent application filed in 1983.
No. 89720 "Incomplete weft insertion thread removal device for shuttleless loom"
It is a device for winding up the incomplete weft thread 12 while pulling it out from the weaving front on the weft insertion side of the woven fabric when the weft insertion is defective, and for guiding the weft thread 12 to the winding position. is provided with a guide tube 13 that is open at the top and bottom, and a cylindrical housing 1 that intersects with this guide tube 13.
It is equipped with 4. And this housing 14
communicates with the inside of the guide cylinder 13 through a guide hole 15.

The thread sensor 1 of the present invention has a holder 2.
The mounting screw 16 inserted into the elongated hole 2a allows the mounting screw 16 to be mounted, for example, to the lower surface of the housing 14 at an appropriate angle. Of course, the mounting position of this holder 2 can be adjusted back and forth within the range of the elongated hole 2a. In this way, the light-emitting element 4 and the light-receiving element 5 are directed toward the inside of the guide tube 13, and the inside thereof serves as the yarn detection area 8.

When a weft insertion failure occurs, the weft thread 12 is blown up by the airflow and sent into the guide tube 13 in a folded state. At this time,
Since the inside of the housing 14 is under negative pressure,
The air inside the guide tube 13 winds up the weft thread 12 and is drawn into the housing 14 through the guide hole 15. In this state, the weft thread 12 is
Inside the housing 14, by the action of a winding body (not shown), it is pulled out from the woven cloth and discharged to a predetermined position.

When the weft thread 12 is guided into the guide tube 13, the thread sensor 1 of the present invention detects the weft thread 12.
Check the existence of That is, when the weft yarn 12 crosses the yarn detection area 8 , the light from the light emitting element 4 is reflected by the weft yarn 12 , and the reflected light enters the light receiving element 5 . As a result, the output voltage of the light receiving element 5 changes, which causes the weft thread 12 to change.
The existence of can be confirmed.

Now, in the present invention, since the light transmitting body 6 forms a smooth surface on the front surface of the light emitting element 4, it is difficult for fluff to adhere to that part, and even if it does adhere to the board, it can be easily accessed from the outside. It is ready to be wiped off. Therefore, even if sensitivity is reduced due to accumulation of fluff or adhesion of dust, oil, etc., these obstacles can be easily removed from the outside. Of course, the transparent body 6 covers the entire surface of the light emitting element 4 and the light receiving element 5 to protect them.

Furthermore, as shown in FIG. 3, the light from the light emitting element 4 is irradiated onto the thread detection area 8 at a certain spread of irradiation angles, but in the process of exiting from the transparent body 6 to the air layer, the density difference between them As a result, the light beam is bent in the direction approaching the light-receiving element 5, so the thread detection area 8 can be enlarged by that amount on the front side of the thread sensor 1, that is, on the front side of the light-receiving element 5, as shown by diagonal lines. become. Note that if the refractive index is larger, the yarn detection area 8
is further enlarged on the front side of the light receiving element 5. As a result, even if the weft yarn 12 crosses the light-receiving element 5 while approaching it, the light beam from the light-emitting element 4 is reflected, so the light-receiving element 5 detects the weft yarn 12 in as wide a range as possible on the near side. It will be possible. Of course, the light beam from the light emitting element 4 is set at an incident angle that does not cause total reflection at the interface between the transparent body 6 and the air, that is, an incident angle that is equal to or smaller than the critical angle.

Modified example of the invention In the above embodiment, both the light emitting element 4 and the light receiving element 5 are covered by the light transmitting body 6, but this light transmitting body 6 covers at least the light emitting element 4, as shown in FIG. It is enough to cover it. In this case, the light receiving element 5 is covered with a hemispherical transparent cover 17 as necessary.
It can also be covered by In such an embodiment, since the light from the light emitting element 4 is bent at the inclined boundary surface, the range of the yarn detection area 8 is further extended to the light receiving element 5.
It can be expanded to the side.

Further, the light shielding section 10 may not be formed as a part of the holder 2, but may be constructed as a support member for the light receiving element 5 by a light shielding body 10a of another member, as shown in FIG.

Furthermore, in both the embodiments shown in FIGS. 1 and 4, the light emitting elements 4 are symmetrically arranged on the left and right positions with respect to one light receiving element 5, but the light emitting elements 4 are If sufficient, only one may be provided.

Of course, the present invention is not limited to the incomplete weft insertion yarn removal device 11 as described above, but can also be used as a detection means for a weft yarn filler.

Effects of the invention In the present invention, the light emitting element and the light receiving element are attached to the recessed part of the holder, and at least the front surface of the light emitting element is covered with a transparent body.
Even when detecting a state in which the weft thread is guided into a narrow space, it is easy to integrate because it does not require an extra space unlike the conventional method. In addition, since the transparent material can be formed smoothly, it is difficult for fluff to adhere to it.
Furthermore, even if they do adhere, they can be easily wiped off along the surface of the transparent body, making inspection easy and preventing malfunctions.

In particular, the light-transmitting body bends the light from the light-emitting element due to the density difference with the air, and bends the light in a direction approaching the light-receiving element, so that the thread detection area can be expanded in front of the light-receiving element. Therefore, even if this yarn sensor is installed in a narrow passage space for yarn, it can detect the presence or absence of yarn more reliably than conventional sensors. When the yarn detection area is expanded on the light-receiving element side in this way, the reflected light from the yarn can be obtained at a position close to the light-emitting element, that is, at a position where there is almost no attenuation of light, so that the yarn detection ability is improved.

[Brief explanation of the drawing]

Fig. 1 is a plan view of the yarn sensor of the present invention, Fig. 2 is a cross-sectional view of the main part of this yarn sensor incorporated into an incomplete weft insertion yarn removal device, Fig. 3 is an optical path diagram, and Fig. 4 is a FIG. 7 is a plan view of another embodiment. DESCRIPTION OF SYMBOLS 1... Thread sensor, 2... Holder, 3... Hollow, 4... Light emitting element, 5... Light receiving element, 6... Translucent body, 7... Inclined surface, 8... Thread detection area, 9... ...Protruding surface, 10... Light shielding part.

Claims (1)

[Claims for Utility Model Registration] (1) A holder having a recess provided near the thread detection area, a light emitting element fixed to the recess of the holder facing the thread detection area, and a light emitting element fixed to the recess of the holder facing the thread detection area; a light-receiving element fixed in a recess of the holder, a light-shielding part that blocks incident light that directly enters the light-receiving element from the light-emitting body, and at least a light-emitting surface of the light-emitting element provided in the recess of the holder. A thread sensor comprising: a translucent body that covers the thread sensor; (2) The yarn sensor according to claim 1, wherein the recess is integrally formed with the holder by filling a light-transmitting material into the recess. (3) The scope of the utility model registration claim, characterized in that depressions are formed symmetrically on the left and right positions across the light-receiving element, and a light-emitting element is fixed to each of the depressions facing the yarn detection area. The yarn sensor according to item 1 or item 2.