JP3438802B2 - 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 weft yarn detector, and more particularly, to an improved weft yarn controllability of a detector having a shape almost the same as that of a reed wing that detects success or failure of weft insertion by a photoelectric method on the weft arrival side. It is about.

In this specification, the expression "front and back" is used. Among them, the "front" means the cloth fell side and the "rear" means the non-woven cloth side.

Further, FIG. 6 shows a typical structure of a detection device to which the present invention is applied. The detection light from the light projecting element 31 crosses the yarn guide groove as shown by the arrow and reaches the light receiving element 32. However, when the weft is properly wefted, the detection light is blocked by the weft in this process. . The "thread guide groove inner wall surface" referred to in the present invention is a wall surface that defines the rear end surface of the thread guide groove shown in FIG. However, it goes without saying that the light emitting and receiving devices may be arranged upside down.

[0004]

2. Description of the Related Art As shown in FIG. 5, in a conventional detecting device, the inner wall surface of the yarn guiding groove is formed of a flat surface parallel to the extending direction of the reed groove. The position is flush with the inner wall surface of the reed groove or slightly recessed.

[0005]

For this reason, as shown by the arrow in the figure, the air jet from the sub-nozzle hits the flat surface and is reflected forward. In many cases, the weft thread that has arrived due to the action of this reflected air jet jumps forward from the reed groove.

As a result, not only the weft insertion becomes unstable, but also a detection error is likely to occur. That is, although weft insertion is actually successful, it is determined that weft insertion is unsuccessful because there is no weft in the reed groove at the detection timing.

In view of the situation of the prior art, an object of the present invention is to cause an air jet reflection of a sub-nozzle in a detection device having substantially the same shape as a reed wing that detects success or failure of weft insertion on the weft arrival side by a photoelectric method. It is to suppress the rampage of the weft.

[0008]

Therefore, in the present invention, in the weft detector of the photoelectric type of the above type,
The gist of the present invention is that the inner wall surface of the yarn guiding groove is projected further forward than the inner wall surface of the reed groove, and that the inner wall surface of the yarn guiding groove is provided with a curved surface shape for reflecting an air jet.

It is preferable that the curved surface is formed so as to start from the back wall surface of the reed groove or from the rear side thereof.

[0010]

The air jet from the sub-nozzle is guided to the curved surface of the inner wall surface of the yarn guiding groove and flows along the inner wall surface of the reed groove by the Coanda effect.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a detection device 3 of the present invention is arranged between rows of reeds 1 and its shape is almost the same as that of reeds.

FIG. 2 shows an embodiment of the detection device of the present invention, in which the yarn guiding groove inner wall surface 33 is formed in a circular curved surface (may be an elliptic curved surface) projecting forward from the reed groove inner wall surface 11. Has been done. It is desirable that the starting point of the curved surface be selected to be the same as the rear wall surface 11 of the reed groove or rearward thereof.

As indicated by the arrow in the figure, the air jet from the sub nozzle flows along the curved surface after hitting the inner wall surface 33 of the yarn guiding groove, and after leaving the end point of the curved surface, by the Coanda effect, the reed groove deep inside. It flows along the wall surface 11. Therefore, the weft yarns normally fly in the yarn guide groove without violently as in the prior art.

FIG. 3 shows another embodiment of the detecting device of the present invention, in which the yarn guiding groove inner wall surface 33 is a flat surface which projects forward from the reed groove inner wall surface 11 and is parallel to the reed groove extending direction. However, the starting point and the ending point of the flat surface are rounded. It is desirable to select the starting point of the curved surface to be the same as or behind the inner wall surface 11 of the reed groove.

In this case, although the air jet is reflected on the flat surface portion, the downstream side of the detector is chamfered, and is drawn into the flow along the yarn guiding groove inner wall surface 33 and the reed groove inner wall surface 11 by the Coanda effect. It does not affect the weft.

FIG. 4 shows still another embodiment of the detecting device of the present invention, in which the yarn guiding groove inner wall surface 33 is flat and intersects with the reed groove extending direction which projects forward from the reed groove inner wall surface 11. The flat surface is formed by chamfering the starting point and the ending point of the flat surface, and the yarn feeding side projects more than the counter yarn feeding side. It is desirable that the starting point of the curved surface is selected to be the same as or behind the inner wall surface 11 of the reed groove.

In this case also, as in FIG. 3, there is reflection of the air jet on the flat portion, but the inclination further reduces the reflection, and there is also the effect of the air flow due to the Coanda effect on the downstream side.
The influence on the weft is further reduced.

To give an example of the structure, the width of the detector is 1
A value of 0 mm is usually used, but the smaller the thickness, the better the result. The degree of protrusion of the thread guiding groove inner wall surface from the reed groove inner wall surface is 2
It is desirable to set up to mm. In the case of a flat surface, it is desirable that the radius of the start point and the end point be about 1 to 5 mm.

[0019]

The Coanda effect in which the air jet of the sub-nozzle flows along the inner wall surface of the reed groove suppresses the weft from jumping forward from the reed groove, stabilizes the weft insertion, and reduces detection errors.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of arrangement of a detection device of the present invention.

FIG. 2 is a horizontal cross-sectional view showing the configuration of an embodiment of the detection device of the present invention.

FIG. 3 is a horizontal cross-sectional view showing the configuration of another embodiment of the detection device of the present invention.

FIG. 4 is a horizontal cross-sectional view showing the configuration of another embodiment of the detection device of the present invention.

FIG. 5 is a horizontal cross-sectional view showing the configuration of a conventional detection device.

FIG. 6 is a cross-sectional view showing the internal structure of the detection device.

[Explanation of symbols]

1 reed feather 11 Reed groove inner wall 3 detector 31 Thread guide inner wall

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) D03D 51/34 101 D03D 47/30

Claims (2)

(57) [Claims] 1. A detection device having substantially the same shape as a reed wing that detects success or failure of weft insertion on the weft arrival side by a photoelectric method, and includes a yarn guide groove and light projecting and receiving light arranged vertically with the yarn guide groove interposed therebetween. A weft detector characterized in that the weft guide inner wall surface projects forward from the reed groove inner wall surface and has a curved surface shape that alleviates the reflection of an air jet from the sub nozzle. 2. The weft yarn detector according to claim 1, wherein the curved surface on the inner wall surface of the yarn guiding groove starts from the inner wall surface of the reed groove or from the rear side thereof.