JPH05302244A - Weft detector of loom - Google Patents

Abstract

PURPOSE:To reduce the loss of a metal member forming a contact part and improve the weft-detecting performance and life of the device. CONSTITUTION:The weft detector of the loom is characterized by containing the first and second members having mutually contacting contact parts 46, 48, respectively, the contact parts being separated from each other with a warp passing therebetween to form an electrically non-conductive state, and one 46 of the contact parts and the other 48 being maintained in the positive potential and in the negative potential, respectively, and the contact part 46 maintained in the positive potential being formed from a noble metal material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention includes first and second members having contact portions which are in contact with each other and which are separated from each other by a weft thread passing therebetween to be in an electrically non-conductive state. , A weft detection device for a loom.

[0002]

2. Description of the Related Art As one of weft detection devices for jet loom, a contact portion between a fixed member and a movable member is always in contact with a direct current electric signal, for example, a direct current is applied between both contact portions. , When the weft passes between both contact parts due to beating, the two contact parts are separated by the weft,
Accordingly, there is a so-called normally-closed type weft detection device that detects the presence of a weft (for example, Japanese Patent Publication No. 49-8833). In this type of weft yarn detecting device, the positional relationship between the fixed member and the movable member is in the vertical direction, and both members gradually approach from the warp supply side toward the cloth winding beam side,
Finally, the two members are arranged on the loom so that they are in line contact with each other. The movable member is made of an elastically deformable material, and its contact portion is elastically deformed by being pressed by the contact portion of the fixed member. When the surplus end of the weft passes between the contact parts due to the beating of the weft, the contact parts are separated from each other by being spread by the surplus end part of the weft. Be placed in an electrically non-conducting state. Therefore, the electrical signal passing between both contact parts is
It represents whether or not both contact portions are in a conductive state, that is, whether or not there is a weft, and is used as a signal for determining the presence or absence of a weft at a predetermined timing each time weft is inserted.

However, in this type of conventional weft detection device, the metal member forming the contact portion is heavily worn, and the weft detection performance deteriorates in a short period of time, resulting in a short life. It is estimated that this is due to the following phenomenon. In a normally-closed type weft detection device, when the weft passes between the contact parts, the contact parts are slightly separated from each other, so that an arc discharge occurs between the contact parts and the melted film contacts. Formed on the part. The film of the melt is an oxide film that is extremely easy to drop off. Further, in the case of the water jet loom, the contact portion is further affected by the surrounding atmosphere such as water and the glue contained in the water, and as a result, an oxide film which is extremely easy to fall off is formed at the contact portion. The oxide film formed on the contact parts is peeled off by the weft thread passing between the contact parts, and the peeled film is moved between the contact parts by the weft thread, and at that time, the metal member of the contact part is scraped off as the film moves. .. As a result of the above, in a normally-closed type weft detection device in which both contact parts are formed of a normal conductive material, particularly a base metal material such as copper, an oxide film that is extremely easy to fall off is present in the contact part due to arc discharge or ambient atmosphere. Since it is easily formed, the metal member forming the contact portion is heavily worn, and the weft detection performance deteriorates in a short period of time.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to reduce wear of a metal member forming a contact portion and improve weft detection performance and device life.

[0005]

A weft detecting device of the present invention has first and second contacting portions that are in electrical contact with each other and that are in contact with each other and are separated by a weft thread passing between them. The second member, which includes first and second members in which one of the contact portions is maintained at a positive potential and the other of the contact portions is maintained at a negative potential, and is maintained at the positive potential The contact portion is formed of a noble metal material.

When the contact portion is made of a noble metal, even if arc discharge occurs between the contact portions, the amount of melt produced by this arc discharge is small, and therefore the oxide film of the melt formed at the contact portion Few. Further, the oxide film of the reduced melt is scraped off by the weft thread passing between the contact portions. Therefore, the metal member forming the contact portion is less worn. Particularly, the oxide film caused by the arc discharge and the surrounding atmosphere is more likely to be formed at the contact portion maintained at the positive potential than at the contact portion maintained at the negative potential. As a result, the wear of the metal member is larger at the positive contact portion than at the negative contact portion.

As described above, according to the present invention, since the contact portion maintained at the positive potential is formed of the noble metal, the oxide film formed on the contact portion is small, and therefore the metal forming the contact portion is small. The wear of the members is small, the weft detection performance is maintained with high accuracy for a long time, and the life is long.

It is preferable that the contact portion maintained at the negative potential is made of a conductive material other than a noble metal material. As a result, it is not necessary to use an expensive noble metal in the contact portion where a small amount of oxide film is formed, and the device becomes inexpensive.
One of the first and second members is a fixed member, the other of the first and second members is a movable member that is elastically deformable with respect to the fixed member, and the movable member has a large elastic coefficient. In addition, it is preferable to use a metal material having corrosion resistance. As a result, jumping or rolling of the movable member can be prevented as compared with the case where the movable member is made of a material having a small elastic coefficient, and therefore the detection performance is improved.

[0009]

EXAMPLE Referring to FIG. 1, a weft yarn 10 is weft-inserted into an opening of a warp yarn 14 by a weft-inserting nozzle 12 and beaten by a reed 16 before weaving. Both ends of the weft yarn 10 are cut by a discarding ear cutter 18, and only one of them is entwined with a discarding twine yarn 20 shown in the figure. Weft detection device 22
Is disposed between the throwing-edge cutter 18 and the throwing-off twine yarn 20 on the side of inserting the weft.

As shown in FIG. 2, the weft detecting device 22 is
A base 24 attached to the frame of the loom, a guide 26 supported by the base 24 so as to extend from the base to the warp supply side, and an electric insulator 30 attached to the side surface of the guide 26 by a plurality of screws 28. , A fixed member 32 attached to the insulator, and a movable member 34 above the fixed member and attached to the insulator 30.

The guide 26 has an elongated hole 36 which is long in the front-rear direction (the warp moving direction), and a screw 38 penetrating the elongated hole 36 allows the position of the base 24 relative to the front-rear direction to be adjusted. Is attached to.

The fixing member 32 has a plurality of elongated holes 40 that are long in the front-rear direction, and a screw 42 that penetrates each elongated hole 40 allows the insulator 30 to be adjusted in its longitudinal position relative to the insulator 30. It is installed. The fixing member 32 is formed of a conductive material having corrosion resistance, and extends from the insulator 30 to the warp supplying side.

The movable member 34 is made of an elastically deformable conductive material, and is attached to the insulator 30 by screws 44 so as to extend from the insulator 30 to the warp supplying side. The movable member 34 is preferably made of a conductive material having a large elastic modulus and corrosion resistance. The tip of the movable member 34 is bent in an arc shape, and acts as a contact portion 48 that is always in contact with the contact portion 46 at the tip of the fixed member 32. In the movable member 34, the contact portion 48 has a contact portion 46.
It is slightly elastically deformed so that it comes into contact with a predetermined pressure.

The fixed member 32 is connected to the positive terminal of a detection circuit (not shown) by the lead wire 50 to maintain the positive potential, and the movable member 34 is connected by the lead wire 52 to the negative terminal of the detection circuit. As a result, the negative potential is maintained. A noble metal such as gold, silver, platinum and alloys thereof is arranged in the contact portion 46 of the fixing member 32 which is maintained at the positive potential. For this precious metal,
For example, a noble metal defined by JIS CP2 can be used. When the movable member 34 is connected to the positive terminal of the detection circuit, a noble metal may be placed on the contact portion 48.

A guide surface is formed at the tips of the guide 26 and the fixing member 32 for guiding the surplus end of the weft 10 between the contact portions 46 and 48. On the reed 18, the weft 10
A push-in member 54 for pushing the surplus end portion of the above between the contact portions 46 and 48 is movably attached together with the reed 18.

When the weft yarn 10 inserted in the opening of the warp yarn 14 is struck by the reed 18 before weaving, this weft yarn 1
The surplus end portion of 0 is contacted by the pushing member 54.
Then, the contact portions 46 and 48 are temporarily separated from each other. As a result, the contact portions 46 and 48 are opened to be in a non-conductive state, so that the signal passing through the contact portions 46 and 48 becomes a signal indicating the presence of the weft, and the detection circuit of the weft detection device 22 detects the presence of the weft. To detect.

When the space between the contact portions 46, 48 is opened and closed by the weft yarn 10, arc discharge is generated between the contact portions 46, 48. However, the contact portion 46 to which the melted material due to the arc discharge tends to adhere, that is, the fixing member 3 maintained at the positive potential.
Since the noble metal is placed in the second contact portion 46, the oxide film of the melt formed in the contact portion 46 by the arc discharge is smaller than in the case where the noble metal is not placed in the contact portion 46. Even when the weft yarn detecting device 22 is applied to a water jet loom, compared to the case where no noble metal is placed in the contact portion 46, water, glue contained in the water, or the like is formed in the contact portion 46 due to the surrounding atmosphere. There are few oxide films.

Therefore, according to the weft yarn detecting device 22, since the oxide film formed on the contact portion 46 is small, the contact portion 4
There are few films peeled off by the weft thread 10 passing between No. 6 and 48, and less metal members are scraped off from the peeled film,
Therefore, the metal members forming the contact portions 46 and 48 are less worn, the weft detection performance is maintained with high accuracy for a long time, and the life is long.

Noble metal may also be arranged on the contact portion 48.
However, since the oxide film caused by the arc discharge and the ambient atmosphere is more likely to be formed on the contact portion 46 maintained at the positive potential than the contact portion 48 maintained at the negative potential, the contact portion 48 is made of a material other than noble metal. It is preferable to use a conductive material. As a result, the cost of the device is lower than that in the case where the noble metal is arranged in the contact portion 48.

Since the movable member 34 is formed of an elastically deformable material, after the weft 10 passes between the contact portions 46 and 48, the movable member 34 bounces with respect to the fixed member 32 and also in the lateral direction. Shaking, which causes both contact parts 46, 4
When 8 is opened and closed a plurality of times, it becomes noise in the detection signal, and the weft detection performance deteriorates. However, the bouncing and rolling of the movable member 34 can be solved by making the movable member 34 from a metal material having a large elastic coefficient, preferably an elastic coefficient E of 150 GPa or more.

The movable member 34 may be a plate member in which the contact between the contact portions 46 and 48 is a line contact, but the contact portion 4
It is preferable that the linear member is such that the contacts of 6, 48 are point contacts. By doing so, by making point contact between the contact portions 46 and 48, the arc discharge is always performed at the same position, so that the oxide film does not exist in the contact portion between the fixed member 32 and the movable member 34. , Both contact parts 46, 48
Since the contact resistance value at is decreased, it can be detected at a low current and can be detected at a low contact pressure.

It is preferable that the position of the fixed member 32 with respect to the movable member 34 in the front-rear direction is changed by the screw 42. As a result, the position of the contact portion 46 with respect to the contact portion 48 can be changed, so that the life of the contact portion 46 can be extended.

As shown in FIG. 3, the contact portion 46 is defined by a member 56 which is separate from the fixing member 32, and the member 56 is formed by an elongated hole 58 extending in the front-rear direction and a screw 60 penetrating the elongated hole. May be attached to the fixing member 32 such that the position thereof can be adjusted in the front-rear direction.

[Brief description of drawings]

FIG. 1 is a plan view showing an example of a cloth fell portion of a loom.

2 is an enlarged sectional view taken along line 2-2 in FIG.

FIG. 3 is a diagram showing another embodiment of a contact portion.

[Explanation of symbols]

 10 weft 12 weft insertion nozzle 14 warp 16 reed 22 weft insertion detection device 26 guide 30 electrical insulator 32 fixed member 34 movable member 46, 48 contact part

Claims (3)

[Claims] 1. A first member and a second member which have contact portions which are in contact with each other and which are separated from each other by a weft thread passing between them to be in an electrically non-conducting state, and one of the contact portions. Includes a first member and a second member whose positive potential is maintained and the other of the contact portions is maintained at a negative potential, respectively, and the contact portion maintained at the positive potential is formed of a noble metal material. Weft detection device for loom. 2. The weft detecting device according to claim 1, wherein the contact portion maintained at the negative potential is made of a conductive material other than a noble metal material. 3. One of the first and second members is a fixed member, and the other of the first and second members is a movable member that is elastically deformable with respect to the fixed member. Is formed of a metal material having a large elastic coefficient and corrosion resistance.