KR100629049B1 - Limit switch - Google Patents

Abstract

By using only one contact portion of the movable contact and the fixed contact, a limit switch can be obtained which improves contact performance and enables long-term use. A rotating shaft that rotates in conjunction with the actuator, a mover provided on the rotating shaft and rotating together with the rotating shaft, a movable contactor having one end mounted to the mover and having a movable contact at the other end, and movable at one end It has a fixed contact which faces a contact, a fixed contact with the other end provided in an external terminal, and a conductive elastic body provided with the one end provided in a movable part and the other end provided in the external terminal different from the said external terminal.

Description

Limit switch {LIMIT SWITCH}             

1 is a side view of a limit switch in Embodiment 1 of the present invention;

Fig. 2 is a longitudinal sectional view of the state in which the main body of the limit switch of Fig. 1 in the first embodiment of the present invention is opened;

3 is a rear view of a state in which the main body of the limit switch in the first embodiment of the present invention is opened;

4 is a front view of the conductive spring used in Example 1 of the present invention;

Figure 5 is a side view of the conductive spring used in Example 1 of the present invention.

Explanation of symbols for the main parts of the drawings

1: Body 1a: Opening

1b: elastic support 2: rotating shaft

3: Actuator 3a: Elastic Body Support

3b: shaft 4: roller

5 elastic body 6 mover

TECHNICAL FIELD This invention relates to the limit switch used for positioning, object detection, etc. in a production facility or an industrial machine.

A conventional limit switch includes a working shaft pressurized by a plunger as a built-in switch, a first contact plate having an intermediate portion inserted through a first holding hole formed by the working shaft and having normally closed contacts at both ends thereof; A second contact plate having an intermediate portion inserted through a second holding hole formed in the operating shaft and having normally open contacts at both ends, and between the inner circumferential surfaces of the first and second holding holes and the first and second contact plates; A contact spring interposed therebetween and a fixed contact adjacent to the normally closed contact and the open contact, respectively, and when the object is in contact with the actuator roller, the fixed contact is moved by moving the plunger coupled with the operating shaft to a straight line. There is an opening separation of the normal closing contact from the contact point, and contacting the open contact with the other fixed contact (see, for example, Japanese Patent Laid-Open No. 1999-238430).

 In the limit switch described in Japanese Laid-Open Patent Publication No. 1999-238430, when the roller of the actuator is pressed against the sensing object and pressurized, the normally closed contacts provided at both ends of the first contact plate are separated from the fixed contact, respectively, and the second contact is made. The built-in switch is configured to open and close by contacting the upper fixed contacts provided at both ends of the plate with other fixed contacts, respectively. However, since the movable contact (upper contact and the normally closed contact) which interlocks with the operation | movement of an actuator is provided in the both ends of a 1st and 2nd contact plate, at the time of opening and closing of a limit switch, there are two contact parts of a movable contact and a fixed contact. It was to exist. For this reason, if a contact failure occurs in at least one of the contact portions formed of the movable contact and the fixed contact, the entire circuit is opened regardless of the contact state of the other contact portion, so that the limit switch functions normally. There is a problem that does not. Moreover, in the limit switch which has two contact parts like the limit switch of Unexamined-Japanese-Patent No. 1999-238430, the probability that the contact part which consists of a movable contact and a fixed contact in one operation will function normally will be N contacts. Speaking of the probability of poor contact occurring to the negative,

[Equation 1]

Pn = (1-N) × (1-N)

Is displayed.

In addition, a limit switch including one movable contact and one fixed contact is also contemplated so that there is one contact portion at the time of opening and closing of the limit switch. Since it is interlocked, when the conductive member, such as an electric wire, is used for the part from the external terminal which connects an external wire to the movable contact, the problem of the bending life of a conductive member deteriorates.

This invention is made | formed in order to solve the above-mentioned subject, The objective is to provide the limit switch which improves contact performance and enables long-term use by making one contact part of a movable contact and a fixed contact.

The limit switch according to the present invention has a rotating shaft that rotates in conjunction with an actuator, a mover installed on the rotating shaft and rotating together with the rotating shaft, one end of which is installed on the mover, and having a movable contact at the other end. A contactor, a fixed contact having a fixed contact opposite to the movable contact at one end, the other end being provided at an external terminal, and a conductive elastic body having one end mounted at the movable part and the other end provided at an external terminal different from the external terminal. It is equipped.

Example 1

Fig. 1 is a side view of the limit switch in Embodiment 1 of the present invention, Fig. 2 is a longitudinal cross-sectional view of the main body of the limit switch in Fig. 1 being opened, and Fig. 3 is a limit in Embodiment 1 of the present invention. It is a rear view of the state which opened the main body of a switch, FIG. 4 is a front view of the conductive spring used in Example 1 of this invention, and FIG. 5 is a side view of this conductive spring.

In the drawing, the rotational shaft 2 is substantially horizontally supported by the substantially box-shaped main body 1 having the opening 1a at the rear thereof over the opposing side surfaces, and at one end of the rotational shaft 2 with an actuator. (3) is fixed. One end of the shaft 3b is fixed to the upper portion of the actuator 3 substantially in parallel with the rotational shaft 2 at a position above the main body 1, and an object to be detected (not shown) on the shaft 3b. The roller 4 in contact with) is rotatably installed. Moreover, the elastic body support part 3a is provided in the lower part of the actuator 3 below the rotation shaft 2. The elastic body support part 1b of the fixed side is provided in the lower part of the main body 1 so that it may oppose this elastic body support part 3a, and the elastic body 5 which consists of a coil spring etc. between these elastic body support parts 1b and 3a. Is installed. The lower part of the actuator 3 is urged toward the semi-elastic support 1b side by the elastic body 5, so that the actuator 3 is always subjected to a force in the clockwise direction about the rotation shaft 2 in FIG. Therefore, the roller 4 provided in the upper part of the actuator 3 will always be pressed toward the opening part 1a side of the main body 1. As shown in FIG. Moreover, the cover 12 is being fixed to the opening part 1a of the main body 1 for dustproofing.

Next, the inside of the main body 1 is demonstrated.

The lower part of the movable part 6 is being fixed to the rotation shaft 2 which rotates in cooperation with the actuator 3 which an external force acts when an object to contact with the roller 4 acts on. A substantially cylindrical conductive through-type metal fitting 7 made of a conductive member is inserted into the central portion of the movable element 6, and the conductive through-type metal fitting 7 is formed at the opening 1a side of the movable element 6. It is penetrated from one side of the surface to the other side facing this side surface. A lower portion of the plate-shaped and conductive movable contact 8 is fixed to the end face of the semi-opening portion 1a side of the conductive through-type metal fitting 7 by a bolt 13a, and the upper portion of the movable contact 8 The movable contact 8a is provided on the same side as the conductive through metal fitting 7. Further, the plate-shaped and conductive fixed contact 9 exhibits a substantially U-shape, and has an upper portion inside the main body 1 such that the U-shaped opening is downward and the opposite side faces parallel to the rotational shaft 2. Installed in The fixed contact 9a is provided in the position which opposes the movable contact 8a of the inner surface side edge part in the one side surface at the side of the opening part 1a among the opposing side surfaces of this fixed contact 9, and the other side is the edge part. It is fixed to the external terminal 10a provided in the side surface which opposes the opening part 1a of the main body 1 by the bolt 13c. Moreover, in the conductive spring 11 which consists of a conductive elastic body which has plate shape and substantially U shape, the fixing hole 11a is formed in the one end, and the fixing hole 11b is formed in the other end. Then, through the fixing holes 11a and 11b, one end portion is provided with the external terminal 10b provided with the same side surface as the external terminal 10a of the main body 1 in the same direction, and the other end portion has a conductive through metal fitting 7 Is fixed by bolts 13d and 13b made of mounting means, respectively, on a U-shaped inner side of the rotating shaft 2 and a conductive through metal fitting 7 on an end face of the opening 1a side of have. 3 and 4, since the conductive spring 11 is provided at a position shifted in the horizontal direction when viewed from the opening 1a side of the main body 1, the bolts 13b and 13d. Is disposed at a position which does not interfere with the conductive spring 11 on the projection surface from the mounting direction.

In the limit switch comprised as mentioned above, since the rotating shaft 2 is always pressurized in the clockwise direction in FIG. 2 by the elastic body 5 provided in the lower part of the main body 1, the movable contact 8a and a fixed contact 9a is in contact, and the whole circuit is in a closed state. Here, when the roller 4 is pressed against the elastic body 5 by the to-be-detected object, the actuator 3 rotates with the rotation shaft 2 about the rotation shaft 2 centering. In addition, since the movable shaft 6 whose lower portion is fixed to the rotating shaft 2 also rotates in association with the actuator 3 by the rotation of the rotating shaft 2, the movable member 6 and the external terminal ( Elastic deformation occurs in the conductive spring 11 having both ends fixed to 10b). In this way, the fixed contact 9a and the movable contact 8a provided in the movable element 6 open-separate, and the whole circuit is opened.

According to the embodiment of the present invention, since the limit switch is provided with only one contact part composed of the movable contact 8a and the fixed contact 9a, the contact point is compared with the limit switch provided with two contact parts as in the prior art. It is possible to improve negative contact reliability. That is, in the limit switch of the embodiment, the probability that the contact portion composed of the movable contact 8a and the fixed contact 9a in a single operation is normal is defined as N probability of contact failure occurring in one contact portion.

[Equation 2]

Pn = 1-N

It is represented by Therefore, it becomes possible to improve the contact reliability of the limit switch by 1 / (1-N) times compared with the conventional structure in which two contact parts existed. In addition, since both ends are provided in the external terminal 10b and the movable element 6, and the conductive spring 11 which is bent every time the rotation of the rotation shaft 2 is performed has electroconductivity and elasticity, electroconductivity, such as an electric wire, Compared with the case where the member is used, the bending life can be significantly extended. In addition, a conductive through metal fitting 7 is inserted into the mover 6, and together with the rotating shaft 2, the mover 6 and the movable contactor 8, the U-shaped inner side of the conductive spring 11. It is arrange | positioned, Since the operation | movement is performed in U-shaped inner side of the conductive spring 11 at the time of the contact / separation of the movable contact 8a and the fixed contact 9a, a limit switch can be made small. Further, bolts for fixing the ends of the conductive spring 11 having the external terminals 10a and 10b in the same direction and having a substantially U-shape to the external terminal 10b and the conductive through-type metal fittings 7 ( 13b and 13d are provided in the position where the electroconductive spring 11 does not interfere on the projection surface from the opening part 1a side of the main body 1. For this reason, when the mounting of the fixed contact 9 to the external terminal 10a and the mounting of the conductive spring 11 to the external terminal 10b and the conductive through-type metal fittings 7, the main body 1 serving as the mounting direction is provided. The bolts 13b, 13c, and 13d can be fastened easily from the side of the opening 1a, the assembly performance is excellent, and the working time can be shortened.

The present invention relates to a rotating shaft rotating in conjunction with an actuator, a mover provided on the rotating shaft and rotating together with the rotating shaft, a movable contactor having one end mounted to the mover and having a movable contact at the other end thereof, And a fixed contact having a fixed contact opposite to the movable contact, having a fixed contact with the other end provided at an external terminal, and a conductive elastic body having one end provided at the mover and an other end provided at an external terminal different from the external terminal. As a result, contact performance is improved by using one contact portion between the movable contact point and the fixed contact point, and it is possible to use for a long time.

Claims (5)

In the limit switch, A rotating shaft rotating in conjunction with an actuator, A mover installed on the rotating shaft and rotating together with the rotating shaft, A movable contactor having one end mounted to the mover and having a movable contact at the other end; A fixed contact having a fixed contact opposite to the movable contact at one end and provided at the other end at an external terminal, A conductive elastic body having one end mounted to the mover and the other end provided at an external terminal different from the external terminal; A mounting means for fixing the conductive elastic body, The said mounting means is provided in the position which does not interfere with the said conductive elastic body on the projection surface from a mounting direction, It is characterized by the above-mentioned. Limit switch. delete delete The method of claim 1, The conductive elastic body is made of a conductive spring having a U-shape, and a movable member is provided inside the U-shape. Limit switch. The method according to claim 1 or 4, Both ends of the conductive elastic body and the other end of the fixed contact are attached in the same direction, characterized in that Limit switch.

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