JP3102059B2 - Limit switch head structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a limit switch head structure, and more particularly to an improvement in a switch operating mechanism provided in a limit switch head.

[0002]

2. Description of the Related Art A conventional switch operating mechanism of this type of limit switch includes a shaft 51 rotatably provided on a head case 50 as shown in FIGS.
A cam operating shaft portion 52 having a substantially semicircular cross section is provided with two cam members 53 and 54, a stopper 56 is provided in a shaft hole 55 of the cam members 53 and 54, and a return spring is provided between the cam members 53 and 54. The two ends of the return spring 57 are engaged with the cam members 53 and 54, respectively, and the cam members 53 and 54 are rotated in opposite directions by the spring force of the return spring 57. The stopper 58 provided on the cam case 53 is brought into contact with a stopper 59 provided on the inside of the head case 50, and the circumscribed cam 6
1 is in contact with the top of the plunger 60.

[0003]

However, such a conventional switch operating mechanism of a limit switch has a problem in assemblability. That is, when assembling to the head case 50, first, the cam members 53 and 54 are attached to both ends of the return spring 57 and inserted into the head case 50, and in this state, the cam member 54 is fixed with a finger. When the shaft 51 is inserted into the cam member 53 and the cam member 53 is rotated to reach the set position (angle), the shaft 51 is inserted into the cam member 54 and assembly is performed. There was a problem.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a limit switch capable of improving assemblability without requiring skill in assembling a switch operation mechanism. The present invention provides a head structure.

[0005]

In order to achieve the above object, the present invention provides a cam member which rotates against a return spring by one-way rotation of a shaft and presses a plunger with a circumscribed cam. A projection is provided on the other cam member, which rotates against the return spring by the rotation of the shaft in the other direction and presses the plunger with the circumscribed cam, and engages the projection of one cam member with the return spring compressed. It is characterized in that a projection is provided for stopping and holding both cam members at the set position.

[0006]

With this configuration, the return spring is compressed, the projection of one cam member is engaged with the projection of the other cam member, the two cam members are held at the set position, and the cam member and the return spring are integrated. The unitized cam assembly can be inserted into a head case and assembled to a shaft.

[0007] For this reason, assemblability can be improved without requiring skill in assembling the switch operating mechanism.

[0008]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a front view of a limit switch according to the present invention. The limit switch 1 includes a box body 2, and a head section 3 is provided above the box body 2.
And a switch operating mechanism 4 is provided in the head portion 3.

The head part 3 has a head case 5 which is provided with a switch operating mechanism housing part 6, a shaft support part 7, a plunger guide mounting part 8, and a pair of stopper parts 39. is there. A support hole 10 is formed in the side surface of the switch operating mechanism housing 6 so as to be located on the axial extension of the shaft support 7.

The switch operating mechanism 4 includes a shaft 14, cam members 17, 18, a return spring 19, and a plunger guide 2.
0 and a plunger (not shown). The shaft 14 includes a roller lever mounting portion 14a, a support shaft portion 23, a cam operating portion 24 having a substantially semicircular cross section, and a support portion 25.

The cam member 17 has a boss portion 26, and a hole 27 of the boss portion 26 has a stopper projection 28 formed along the axial direction. A projection 26a is formed at the inner end of the boss 26, and the projection 26a
It is formed over a ４ circumference. A circumscribed cam 29, a stopper 30, and a spring locking portion 31 are provided around the boss portion 26, and a spring is located inside the circumscribed cam 29, the stopper 30, and the spring locking portion 31. An insertion portion 32 is formed.

Further, the cam member 18 is provided with the cam member 1 described above.
7 has the same configuration as that of FIG. 7, and the corresponding parts are indicated by adding 'to the reference numerals. The plunger has a guide portion 37 at the top thereof, and the guide portion 37 has a pair of cam contact surfaces 38 formed thereon.

Then, one end of the return spring 19 is inserted into the spring insertion portion 32 of the cam member 17 and the cam member 18 is inserted.
The other end of the return spring 19 is inserted into the spring insertion portion 32 ', the first jig 40 is inserted into the cam member 18, the cam member 17 is pressed with a finger, and the projections 26a, 26a' are separated from each other. To rotate the cam member 18 to lock one end of the spring wire 19a to the spring locking portion 31 and lock the other end of the spring wire 19a to the spring locking portion 32 'to compress the return spring 19. When the set position (the circumscribed cams 29, 29 'of the cam members 17, 18 are oriented in the same direction) is reached, the cam member 1
8 is brought close to the cam member 17 side, and the side edge 26b 'of the projection 26a' is locked to the side edge 26b of the projection 26a to form a unit, thereby forming the cam assembly A. In this case, the protrusion 26a 'of the cam member 18 hits the protrusion 26a of the boss 26 of the cam member 17, and the cam members 17, 18
No rotation at 9

Next, the cam assembly A is gripped by the second jig 41 while the projections 26a and 26a 'are in contact with each other, and the first jig 40 is pulled out of the cam assembly A. Next, the second
The cam assembly A is gripped by the jig 41 of FIG.
The cam operating part 24 having a substantially semicircular cross section is inserted into the plunger-operating mechanism housing part 6 of the cam member 5 and the shaft 14 is inserted from the shaft bearing part 7 side.
And the flat portion 24a of the cam operating portion 24 is
8, 27 stopper holes 27 'of the holes 27', 27,
28, and the bearing 25 of the shaft 14 is
The shaft 14 is rotatably supported in the bearing hole 10 of the shaft 5, and the bearing shaft 23 of the shaft 14 is rotatably supported on the shaft support 7 via the O-ring 14b and the oil seal 14c. The cam assembly A is fitted to the shaft 14 by fitting into the ring groove 14e.

Then, the plunger is inserted into the plunger guide 20, the plunger guide 20 is mounted on the head case 5, and the circumscribed cams 29,
29 'is in contact with the cam contact surfaces 38, 38 of the plunger.

The head structure thus constructed is fitted to the upper part of the box body 2 and mounted on the box body 2 by mounting bolts (not shown). An end of the plunger is in contact with an actuator of a switch body (not shown) provided in the box body 2, and a roller lever mounting portion 14a of the shaft 14 is provided with a roller. Lever
5a is attached.

Next, the operation of the limit switch configured as described above will be described.

The operating body (not shown) moves, and the roller
The shaft 1 is brought into contact with the lever 5a by pushing it.
4 rotates in one direction. When this rotation direction is the left direction in FIG. 3, the stopper 30 of one cam member 17 abuts against the stopper portion 39, and the cam member 17 rotates left against the return spring 19, The circumscribed cam 29 of the cam member 17 pushes the cam contact surface 38 of the plunger,
By moving the plunger, the operator of the switch body is pressed to switch on.

When the rotation direction of the shaft 14 is rightward in FIG. 3, the stopper 30 ′ of the other cam member 18 abuts against the stopper portion 39, and the cam member 17 is opposed to the return spring 19. Rotating clockwise, the circumscribed cam 29 of the cam member 17 pushes the cam contact surface 38 of the plunger, moves the plunger against the return spring, and presses the operator of the switch body to switch on. Let it. When the shaft 14 is rotated to the left, the cam member 18 is rotated.
Rotates against the return spring 19, and the circumscribed cam 29 'operates the plunger to switch on.

According to the above embodiment, the cam members 17, 1
8 and the return spring 19 can be integrally assembled into a unit, and the unitized cam assembly A can be inserted into the head case 5 to assemble the cam assembly A to the shaft 14, and the switch can be assembled. The assemblability of the operating mechanism 4 is improved.

[0021]

As described above, the head structure of the limit switch according to the present invention is constructed such that the rotation of the shaft in one direction causes the cam member to rotate against the return spring and press the plunger with the circumscribed cam. A projection is provided, and the other cam member which rotates against the return spring by rotation in the other direction of the shaft and presses the plunger with the circumscribed cam is engaged with the projection of one cam member while the return spring is compressed. Since the projections for holding the two cam members at the set position are provided, the return spring is compressed, and the projection of one cam member is engaged with the projection of the other cam member to hold the two cam members at the set position. The member and the return spring can be integrally assembled into a unit, and the unitized cam assembly can be inserted into a head case and assembled to a shaft.

[0022] For this reason, assemblability can be improved without requiring skill in assembling the switch operating mechanism.

[Brief description of the drawings]

FIG. 1 is a front view of a limit switch according to the present invention.

FIG. 2 is a longitudinal sectional view of a head structure of a limit switch according to the present invention.

FIG. 3 is a sectional view of the head structure.

FIG. 4 is an exploded perspective view of the head structure.

FIG. 5A is a perspective view of a cam assembly using a first jig. (B) shows the case where the cam assembly is caged using the second jig.
FIG. 4 is an exploded perspective view when the device is incorporated into a device.

FIG. 6 is a longitudinal sectional view of a conventional limit switch head structure.

FIG. 7 is a sectional view of the head structure.

FIG. 8 is a perspective view of the head structure in an exploded state.

[Explanation of symbols]

 14 Shaft 17 Cam member 18 Cam member 19 Return spring 26a Projection 26a 'Projection

Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01H 21/28

Claims (1)

(57) [Claims] 1. A projection is provided on one cam member which rotates against a return spring by one-way rotation of a shaft and presses a plunger with a circumscribed cam, and which is opposed to the return spring by rotation of the shaft in another direction. Rotate and plunger with circumscribed cam
A head member of a limit switch, wherein the other cam member that presses the return spring is provided with a protrusion that locks the protrusion of one of the cam members in a state where the return spring is compressed and holds both cam members in a set position. .