JPH03180548A - Weft feeler of loom - Google Patents

Abstract

PURPOSE:To enable sure weft detection in high speed air jet weaving by inserting an assistant optical system using light of light-emitting element as parallel line having rectangle cross section in an optical system constituting weft filler arranged in the vicinity weft running path. CONSTITUTION:A weft filler formed of an optical system consisting of the first and second to wholly reflecting prisms inserted and attached in a gap between light-emitting element 11 having high directing property and dent 1 through weft guide groove RG formed in the dent 1 and light-intercepting element 14 is arranged and set. An assistant optical system consisting of the first reflecting body 21 having projected face and the second reflecting body 22 having recessed face is inserted between the above-mentioned light-emitting element 11 and the first prism 12 in at least longitudinal direction and constituted so as to introduce light into the above mentioned first prism 12 after light of light-emitting element 11 containing central light shaft La is formed into parallel line having rectangle and light projecting to allowable weft running religion in the above-mentioned weft guide groove RK is kept so as to have sufficiently large and uniform luminous intensity over total range of the cross section.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a weft feeler for a loom for accurately detecting a weft inserted into the loom.

In prior art looms, a weft feeler is used to determine whether weft insertion has been performed normally.

Various types of weft feelers have been developed for a long time, but among them, transmission-type optical weft feelers are
For example, even when applied to a high-speed loom such as a jet loom, it can operate stably.

Generally, a light emitting element and a light receiving element are arranged as a pair near the weft flight path above the liquid, and the light from the light emitting element is
The light reaches the light receiving element by crossing the weft running path, and when the weft inserted into the weft running path blocks the light, the amount of light that enters the light receiving element decreases. The weft can be detected by binding and taking it out. As the light emitting element, in addition to general incandescent lamps, various light emitting elements such as light emitting diodes and semiconductor laser elements are used, and as the light receiving elements, photoelectric conversion elements such as photodiodes, phototransistors, and photovoltaic cells are used. Therefore, one with sufficient sensitivity and responsiveness is selected.

Some transmission-type optical weft feelers are known in which a pair of light reflecting members are inserted between the reed feathers so as to sandwich the weft flight path from above and below (Unexamined Japanese Patent Publication No. Publication No. 60-104560, Publication No. 63-295743). The light from the light emitting element is deflected by one of the light reflecting members, crosses the weft flight path, and reaches the light receiving element via the other light reflecting member, so that it can operate in the same way. This product is made by assembling a light-reflecting member, a light-emitting element, and a light-receiving element.

can be inserted between the reed blades, it is easy to maintain the optical axis from the light emitting element correctly on the weft flight path and the light receiving surface of the light receiving element, and therefore mechanically high operational stability is achieved. can be obtained.

The problem to be solved by the invention is, as described above, when using such prior art,
Even if it is easy to obtain mechanically good stability, there is a problem in that it is not easy to electrically achieve a necessary and sufficient S/N ratio.

In other words, when an optical system including a light reflecting member is inserted into the reed blades, if the light emitting element serving as the light source is large, only a portion of the luminous flux from the light emitting element will be introduced between the reed blades. Therefore, it is desirable to use a light emitting element as small as possible. on the other hand,
Since small light emitting elements generally do not have a large amount of total luminous flux, it is necessary to use one with a powerful condensing lens to provide sharp directivity characteristics and increase the S/N ratio of the output signal. However, when the luminous flux is narrowed down in this way, good S
/N ratio, it is difficult to achieve stable weft detection ability in other areas due to insufficient luminous intensity.

Especially 1. In a wide, high-speed air jet room, the tips of the weft yarns vibrate greatly, so it is necessary to set a wide allowable flight range for the weft yarns, and with conventional weft yarns, it is difficult to achieve a sufficient S/N ratio over that entire range. The situation was that it was extremely difficult.

Therefore, in view of the problems of the prior art, an object of the present invention is to convert light from a light emitting element with high directivity characteristics into parallel light beams with a rectangular cross section including the central optical axis, and to introduce the parallel light beams between the reed blades. Accordingly, an object of the present invention is to provide a weft feeler for a loom that can easily realize a necessary and sufficient S/N ratio in the entire range even when the allowable flight range of the weft is wide.

Means for Solving the Problems The structure of the present invention to achieve the object is to form an optical system for weft detection through a weft guide groove formed in the reed blades when it is inserted into the gap between the reed blades. The light emitting element includes a light emitting element, first and second total reflection prisms, and a light receiving element, and between the light emitting element with high directivity and the first total reflection prism, the light from the light emitting element including the central optical axis is shaped into a rectangular cross section. The first parallel ray of
The gist is to install an auxiliary optical system that guides the light to the total reflection prism.

Note that the auxiliary optical system may include at least a first reflector that is convex in the vertical direction and a second reflector that is concave in the at least vertical direction.

Therefore, when using this configuration, the light from the light emitting element is
By passing through the auxiliary optical system, the light enters the first total reflection prism as a parallel light beam with a rectangular cross section including its central optical axis. Therefore, the auxiliary optical system is designed so that the cross section of the light incident on the first total reflection prism becomes a rectangular cross section corresponding to the maximum cross section formed by the gap between the reed blades and the maximum width of the allowable flight area of the weft. If the characteristics are determined, the first total reflection prism will cause
Of the light emitted from the light-emitting element, only the light within an extremely narrow range around the central optical axis can be effectively used as the light projected onto the permissible flight range of the weft within the weft guide groove. A uniform and sufficient luminous intensity can be easily achieved over the entire allowable flight range. Therefore, if the second total reflection prism focuses the light that has passed through the permissible flight range of the weft threads onto the light receiving surface of the light receiving element, the output signal of the light receiving element will reflect all the weft threads within the permissible flight range. On the other hand, a good S/N ratio can be obtained.

An auxiliary optical system is formed by the first reflector and the second reflector, and the former is convex at least in the vertical direction, and the latter is concave at least in the vertical direction. Since the light can be diffused in the vertical direction by the former and then converted into parallel rays by the latter, the permissible flight area of the weft is large, and the incident cross section of the light to the first total reflection prism is long in the vertical direction. Even if it is necessary, it is possible to easily keep the luminous intensity constant over its entire length. This is because even light from a light emitting element with high directivity characteristics has a nearly uniform luminous intensity distribution in a narrow region around its central optical axis.

Example Examples will be described below with reference to the drawings.

The weft feeler of the loom includes a light emitting element 11 and a first reflector 2.
1 and a second reflector 22, a first total reflection prism 12, a second total reflection prism 13, and a light receiving element 14 (FIG. 1).

The first and second total reflection prisms 12.13 are integrally assembled so as to be sandwiched between a pair of thin plate members (not shown), and are formed so as to be insertable into the gap d of the liquid state R1, R1 of the reed R. There is. A weft guide groove RG is formed on the weaving side of the liquid R (, R1).

The first total reflection prism 12 has its oblique side at an apex angle θζ4
The second total reflection prism 13 has a reflective surface 12a having a diagonal angle of 5 (degrees), and the oblique side thereof is formed with a reflective surface 12a having an appropriate curved surface.
3a. The reflective surfaces 12aN 13a face each other, and therefore the first and second total reflection prisms 12.13 are optically coupled via the weft guide groove RG. First and second total reflection prisms 12.1
3, the rear end surfaces 12b and 13b that serve as light passages and the end surface 12cs13c facing the weft guide groove RG are coated with an antireflection coating known as a transparent film, and For surfaces 12a, 13a,
It is preferable to apply a reflective treatment such as aluminum vapor deposition.

The first and second total reflection prisms 12.13 have an end surface 12c.
, 13c are inserted into the gap d of the liquid RI SR1 so as to match the lower and upper sides of the weft guide groove RG.

A case body C that houses the light emitting element 11, the first reflector 21, the second reflector 22, and the light receiving element 14 is disposed at the rear of the first and second total reflection prisms 12, 13.

The light emitting element 11 is optically coupled to the first total reflection prism 12 via an auxiliary optical system consisting of a first reflector 21 and a second reflector 22, and the light receiving element 14 is optically coupled to the first total reflection prism 12. It is assumed that the total reflection prism 13 is optically coupled to the total reflection prism 13 of No. 2. Therefore, the light emitting element 11, the first reflector 2
1, second reflector 22, first total reflection prism 12, second
The total reflection prism 13 and the light receiving element 14 form a series of optical systems via the weft guide groove RG.

That is, the light from the light emitting element 11 passes through the first reflector 21,
After being reflected by the second reflector 22, it is projected from the rear end surface 12b of the first total reflection prism 12 into the first total reflection prism 12, and after being totally reflected by the reflection surface 12a, the weft yarn guide groove RG The light enters the second total reflection prism 13, is totally reflected again by the reflection surface 13a, and enters the light receiving element 14.

The first reflector 21 is convex in the vertical direction (referring to the cross-sectional direction XX in FIG. 1, the same applies hereinafter), and concave in the horizontal direction (referring to the cross-sectional direction Y-Y in the same figure, the same hereinafter). The second reflector 2 reflects light from the light emitting element 11 including the central optical axis La.
Reflect towards 2.

The second reflector 22 is a reflector that is concave both in the vertical and horizontal directions, and converts the light including the central optical axis La reflected by the first reflector 21 into parallel rays. It is reflected toward total reflection prism 12 of No. 1.

When a weft (not shown) is inserted into the weft guide groove RG, an allowable flying area Ka is defined as an area where the presence of the weft is allowed. Its shape is generally a fan-shaped area in the upper depths of the weft guide groove RG. Therefore, the light from the light emitting element 11 passes through the first reflector 21 and the second reflector 22, enters the first total reflection prism 12, is reflected by its reflection surface 12a, and crosses the allowable flight area Ka. However, at this time, the characteristics of the auxiliary optical system consisting of the first reflector 21 and the second reflector 22 are determined as follows.

First, consider the maximum cross section 31=dXL formed by the gap d of the reed wings R1 and R1 and the maximum width of the allowable flight area Ka.

However, the maximum width is taken in the direction perpendicular to the light that crosses the allowable flight area Ka. Further, an arbitrary virtual plane P is taken at right angles to the central optical axis La of the light incident on the first total reflection prism 12, and the maximum cross section S1 is projected onto the virtual plane P via the reflective surface 12a. Incidence cross section 32 = d2
Define it as XL2.

Therefore, when the light from the light emitting element 11 passes through the incident cross section S2, the rectangular cross section S3 including the central optical axis La = d3
It is a parallel ray of XL3, and the incident cross section S2
The characteristics of the auxiliary optical system are determined so that the luminous intensity distribution within the area is approximately uniform. That is, when the directional characteristic of the light emitting element 11 is sharp as shown in FIG. 2, a small angular range Oo including the central optical axis La and corresponding to the minute relative luminous intensity difference δ is determined, and θl≦θo1θ2≦ Angle range θ of θ0
1. The curved surface shapes of the first reflector 21 and the second reflector 22 may be selected so that the light within θ2 is converted into parallel rays with a rectangular cross section and reaches the incident cross section S2 (Fig. 3). . However, the rectangular cross section 33 = d3XL3 is da', d2
, L3'', L2, and d3≧d2, L3≧L2, the rectangular cross section S3 approximately corresponds to the maximum cross section S1 formed by the gap d of the reed wings R1, R1 and the maximum width of the allowable flying area Ka. shall be allowed to do so.

Here, FIGS. 3(A) and 3(B) schematically show cross sections in the XX direction and Y-Y direction of FIG. 1, respectively, and therefore the angular ranges θ1 and θ2 are respectively , indicates the vertical and horizontal angular range of the width of the light reflected by the auxiliary optical system. Note that it is preferable to provide a suitable shield C2 on the front surface of the case body C having an opening CI that matches the size of the rectangular cross section S3;
Regardless of FIGS. 1 and 3, the case body C and the first and second total reflection prisms 12.13 are brought into close contact with the rear end surfaces 12b and 13b of the first and second total reflection prisms 12.13. It is sufficient to assemble them in one piece.

However, the first total reflection prism 12 has a rear end surface 12
It is assumed that the size of b is not smaller than the incident cross section S2, and that the reflective surface 12a can project the entire range of the maximum cross section S1 onto the virtual plane P.

In this way, the light that enters the first total reflection prism 12 passes through the allowable flight area Ka while crossing the weft guide groove RG, but at that time, the light that crosses the allowable flight area Ka is It becomes a parallel light beam that includes the central optical axis La and has a nearly uniform luminous intensity. Therefore, if the curved shape of the reflective surface 13a of the second total reflection prism 13 is determined so that the entire luminous flux passing through the maximum cross section S1 of the allowable flight area Ka is focused on the light receiving element 14, the light receiving element 14 The output signal from
It is possible to realize a sufficiently large S/N ratio that is approximately constant regardless of the presence or absence of a weft yarn at any position within the allowable flying area Ka.

Note that the light emitting element 11, the first reflector 21, the second reflector 22
In order to maintain a predetermined relative positional relationship within the case body C, the light receiving element 14 is preferably filled entirely inside the case body C with a transparent resin or the like.

The first reflector 21 generally needs to be convex in the vertical direction in order to diffuse the light from the light emitting element 11 within a narrow angle range θ0 into a vertically long rectangular cross section S3. Also, the second
The reflector 22 may be concave in the vertical direction in order to convert the light thus diffused into parallel light rays. However, if the first reflector 21 is further concave in the lateral direction, the angular range θ1≦00 in the lateral direction is widened, and the incident cross section S2,
Advantageously, the luminous intensity at the largest cross section 31 can be further increased. Conversely, when the maximum luminous intensity of the light emitting element 11 is sufficiently large, the first reflector 21 does not necessarily need to be concave in the lateral direction. Further, in this case, the second reflector 22 does not necessarily need to be concave in the lateral direction when the light within the angular range θl can be regarded as substantially parallel rays.

In the above description, the first reflector 21, the second reflector 22
The auxiliary optical system consisting of a lens system, a mirror system, and a prism can be used to create parallel rays of uniform luminous intensity with a predetermined rectangular cross section S3 by using a part of the light from the light emitting element 11 with high directivity. It is possible to change to any optical system such as the optical system.

A light emitting element 11, a light receiving element 14, and a first incidental thereto,
Of course, the second total reflection prisms 12 and 13 may be installed upside down, but generally, as shown in Fig. 1, the light passes through the weft guide groove RG from bottom to top. By doing so, the light receiving end surface 13c faces downward, so that the influence of disturbances caused by ceiling lighting and the like can be reduced.

In addition, the light emitting elements 11 may be used in any number of 2 or more depending on their directional characteristics and the size of the allowable flight area Ka, and in this case, the light emitting elements 11 correspond to a long rectangular cross section S3 in the vertical direction. Therefore, it is preferable to arrange a plurality of light emitting elements 11, 11, . Furthermore, the light incident on the first total reflection prism 12 and the light exiting from the second total reflection prism 3 do not necessarily have to be perpendicular to the rear end surfaces 12b and 13b, unless harmful reflection occurs. Of course it's a good thing.

Further, as the light emitting element 11 in the present invention, any light source such as an incandescent bulb, a light emitting diode, or a semiconductor laser element can be used alone or in combination with a condensing lens or the like.

As described in detail, according to the present invention, a light emitting element and a first
An auxiliary optical system is interposed between the total reflection prism of the first total reflection prism, and this auxiliary optical system converts the light from the light emitting element including the central optical axis into parallel light beams with a rectangular cross section and passes it to the first total reflection prism. By guiding the light, the light projected onto the permissible flight area of the weft in the weft guide groove through the first total reflection prism is sufficiently large and has a uniform luminous intensity over the entire range of its maximum cross section. Therefore, even for high-speed air jet rooms where the permissible flight range is wide,
It has the excellent effect of being able to obtain an output signal with a good S/N ratio and being able to be applied without any problems.

[Brief explanation of drawings]

1 to 3 show examples, FIG. 1 is an exploded perspective view of the entire structure, FIG. 2 is a directional characteristic diagram of a light emitting element, and FIG.
A) and (B) are x-X line and Y-Y line in Fig. 1, respectively.
FIG. 3 is a schematic explanatory diagram corresponding to a cross section taken along the line. R1... Reed feather d... Gap RG... Weft guide groove La... Central optical axis 11... Light emitting element 12... First total reflection prism 13... Second total reflection Prism t4... Light receiving element 21... First reflector 22... Second reflector

Claims (1)

[Scope of Claims] 1) A light emitting element and first and second total reflection prisms that form an optical system for weft detection through a weft guide groove formed in the reed blades when inserted into the gap between the reed blades. and a light receiving element, the light from the light emitting element including the central optical axis is transmitted between the light emitting element having a high directivity characteristic and the first total reflection prism as parallel light beams having a rectangular cross section. A weft feeler for a loom, characterized in that an auxiliary optical system is interposed to guide the first total reflection prism. 2) The weft of a loom according to claim 1, wherein the auxiliary optical system includes at least a first reflector that is convex in the longitudinal direction and a second reflector that is concave in the longitudinal direction. Feeler.