JP3175294B2 - Limit switch - 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 that is mechanically opened and closed by an external operation of an actuator.

[0002]

2. Description of the Related Art FIG. 8 is a partial sectional front view of a limit switch showing a conventional example. In the figure, 10 is a case for storing a switch 12 having a push button 11, and 13 is one end of the case.
An actuator having a retaining ring 14 fitted on the outer periphery of the case 10 projecting outside and having the other end inserted into the hole 10a of the case 10,
The actuator 13 is slidable in the case 10 in the axial direction, and a retaining ring 14 prevents the actuator 13 from slipping upward. Fifteen
Is a hole provided along the axis from the other end of the actuator 13, and 16 is a push rod which is housed in the hole 15 provided in the actuator 13 and presses the push button 11 by a pressing operation of the actuator 13, and is stopped below. The ring 19 is fitted. Reference numeral 17 denotes a plurality of annular guides fitted on the outer periphery of the push rod 16.
Are guided along the axis of the actuator 13. Also,
Reference numeral 18 denotes a retaining ring 14 fitted to an actuator 13 and a case 10
A return spring 20 is interposed between the stepped portion 10b and an operation spring 20 interposed between the actuator 13 and the push rod 16 so that both ends thereof abut on the guides 17, 17.

In the above-described structure, when the actuator 13 is pressed from the outside by a detector (not shown), the actuator 13 moves downward in the hole 10a of the case 10 against the spring force of the return spring 18. . A push rod 16 is inserted into the hole 15 of the actuator 13, and the push rod 16 moves downward with the actuator 13 to press the push button 11 of the switch 12. When the actuator 13 is further pressed, the operation spring 20 inserted between the actuator 13 and the push rod 16 bends, and only the actuator 13 slides, so that the operation spring 20 absorbs the overstroke of the actuator 13.

[0004]

However, in such a conventional limit switch, the components constituting the limit switch are concentrated in a hole provided in a case, and the limit switch is assembled. Has a drawback that it is complicated because of the complicated parts and the assembly work is difficult.

In view of the above, an object of the present invention is to provide a limit switch which simplifies the structure of a limit switch and facilitates an assembling operation.

[0006]

SUMMARY OF THE INVENTION In view of the above, the present invention has an upper opening, a front opening and a rear opening which are opened in a direction orthogonal to the upper opening. And a switch element part attached to the front side of the case, a switch element part having a push button of the switch element protruding from the front opening part, and inserted into the case from the rear opening part of the case, and into the front opening part. It is positioned in contact with the contact part formed on the continuous case inner wall and the contact part formed on the case inner wall continuous with the upper opening, and slides in the direction perpendicular to the line connecting the front opening and the rear opening. A push rod capable of opening and closing the switch element, inserted between the push rod and the case, and pressing the push rod against an abutting portion connected to the upper opening of the case to oppose the push rod and the upper opening of the case; Return spring to form a gap between the inner wall surface of, it is inserted from the upper opening of the case,
The push rod is fitted into the push rod so as to prevent the push rod from coming off in the direction of the rear opening, and a pressing movable portion including an actuator that slides in the same direction as the push rod, and is inserted between the actuator and the push rod, and the push rod and the case Stroke absorption consisting of an operation spring that has a larger contraction dimension than the gap between the inner wall surface on the opposite side of the upper opening and has a larger force than the return spring, and absorbs the overstroke when pressing the actuator. And a unit.

[0007]

In the construction described above, the limit switch mechanism is divided for each function, that is, a case having an upper opening, a front opening, and a rear opening, and each opening communicates with each other. A push element, a push rod for opening and closing the switch element, a return spring, and a pressing movable section comprising an actuator fitted to the push rod; and a stroke absorbing section comprising an operation spring for absorbing an overstroke when the actuator is pressed. The configuration of the limit switch is simplified. To assemble the limit switch thus divided, a push rod is inserted into the case through an opening on the rear surface of the case, a return spring is inserted between the push rod and the inner wall surface of the case, and then the upper side of the case is The operation is completed by inserting the operation spring through the opening and inserting the actuator into the push rod from above the operation spring.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are a longitudinal sectional view of the limit switch and a front view of FIG. FIG. 3 is a plan view of FIG.
FIG. 3 is a diagram showing an assembled state of the actuator on the push rod. In the figure, reference numeral 1 denotes an upper opening 1b having a notch 1a (see FIG. 3) on the upper surface, a concave portion 1c provided on an inner wall surface opposite to the upper opening 1b, and a direction orthogonal to the upper opening 1b. A case composed of a front opening 1d and a rear opening 1e that are open, and each opening communicates with each other. 2 has a push button 2a for opening and closing a switch, and is attached to the front side of the case 1 by a screw 3. Switch element 4 is the case 1
Is inserted into the case 1 through the rear opening 1e, and the front opening
A push rod slidably housed in a direction orthogonal to a line connecting 1d and the rear opening 1e. The push rod 4 is located above the push button 2a of the switch element 2 and is pushed by an actuator 6 to push the push button 2a. And a concave portion 4b provided at an upper portion into which one end of an operation spring 7 for absorbing an overstroke at the time of pressing operation of the actuator 6 is fitted.
And a projection 4c provided below at which one end of the return spring 5 is fitted, and vertical grooves 4d (see FIG. 4) provided on both side surfaces.

A push rod 4 is inserted between a recess 1c on the inner wall surface of the case 1 and a projection 4c below the push rod 4.
Is pressed against a contact portion 8b formed on the inner wall of the case 1 connected to the upper opening 1b of the case 1 to form a gap 9 between the push rod 4 and the inner wall surface on the opposite side of the upper opening 1b of the case 1. The return spring 6 has a leg 6a (see FIG. 4) fitted into the vertical groove 4d of the push rod 4, and has a substantially U-shape having a projection 6b into which one end of the operation spring 7 is fitted at the center of both legs 6a. The actuator 6 is inserted through the upper opening 1b of the case 1 and the leg 6a of the actuator 6 is fitted into the vertical groove 4d of the push rod 4, thereby preventing the push rod 4 from coming off in the direction of the rear opening 1e. Done, leg of actuator 6
6a can slide the vertical groove 4d. Reference numeral 7 denotes an operation spring inserted between the recess 4b of the push rod 4 and the protrusion 6b of the actuator 6, and the operation spring 7 is provided between the push rod 4 and the inner wall surface on the opposite side of the upper opening 1b of the case 1. It has a larger contraction dimension than the gap 9 and has a larger force than the return spring 7, and ensures a sufficient stroke when the actuator 6 is pressed. Since the stroke regulation for the switch element 2 is determined only by the relationship between the case 1 and the push rod 4, the combination dimensional accuracy is improved. Note that the gap 9 between the case 1 and the push bar 4 matches the stroke when the push bar 4 presses the push button 2a of the switch element 2.

Next, the assembly of the limit switch will be described.
First, the push button 2a is provided on the front side of the case 1 as described above.
The switch element 2 is mounted so as to protrude from the case 1, and the push rod 4 is inserted from the rear opening 1 e of the case 1 with the arm 4 a first, and the push rod 4 is connected to the front opening 1 d.
Into the contact portion 8a formed on the inner wall of the device.
The arm 4a of the push rod 4 passes through the front opening 1d of the case 1,
It is located above the push button 2a of the switch element 2 attached to the front side of the case 1. At this time, the push rod 4 is the front opening
The contact portion 8a formed on the inner wall of the case 1 connected to 1d and the contact portion 8b formed on the inner wall of the case 1 connected to the upper opening 1b are brought into contact with each other to maintain the relative positional relationship with the switch element 2. I have. Next, the return spring 5 is inserted between the projection 4c of the push rod 4 and the recess 1c provided on the inner wall surface of the case 1. Then, one end of the operation spring 7 is inserted into the concave portion 4b provided on the upper surface of the push rod 4 inserted into the case 1 from the upper opening 1b of the case 1. Then, the substantially U-shaped actuator 6 is inserted from the upper opening 1b of the case 1 so that the legs 6a of the actuator 6 are fitted into the vertical grooves 4d on both sides of the push rod 4, and the other end of the operation spring 7 Are fitted into the protrusions 6b of the actuator 6, and the leg portions 6a are fitted into the vertical grooves 4d on both side surfaces of the push rod 4 by pressing from above. At this time, since the outside of the leg 6a of the actuator 6 is fitted into the notch 1a on the upper surface of the case 1, the push rod 4 can be prevented from dropping in the direction of the rear opening 1e of the case 1. In this way, the limit switch can be assembled. The above assembly is for Case 1
, A push rod 4, a return spring 5, an actuator 6,
Since the operation is completed when the operation spring 7 is fitted, the assembling work can be easily performed without using components such as screws.

As described above, the configuration of the limit switch described above includes a switch element portion as a main element, a pressing movable portion including a push rod for opening and closing the switch element, a return spring, and an actuator, and an over-pressure member when the actuator is pressed. It is clearly divided into a stroke absorbing portion made of an operation spring for absorbing a stroke. Then, the assembly is completed by sequentially incorporating each element into the case.

The push rod 4 and the actuator 6 are assembled by providing a vertically long hole 6c in the leg 6a of the actuator 6 and engaging the hole 6c in the vertical groove 4d of the push rod 4 as shown in FIG. Alternatively, a protrusion 4e may be provided, and the hole 6c may be fitted into the protrusion 4e. At this time, the assembly of the push rod 4 and the actuator 6 is performed by the leg portion having the hole 6 c of the actuator 6.
6a is pressed from above so as to fit into the vertical groove 4d provided with the projection 4e of the push rod 4, and the leg 6a of the actuator 6 is bent outward, and the hole 6c provided in the leg 6a is vertically What is necessary is just to engage with the projection part 4e provided in the groove 4d. By doing so, it is possible to prevent the actuator 6 from coming off the push rod 4 upward.

FIGS. 6 and 7 are a longitudinal sectional view of a roller lever type limit switch in which the limit switch of the present invention is housed in a waterproof case 30 and a front view with a cover removed. In the figure, lever is applied by external force.
When the 40 slides from the neutral position, the rotating shaft 4 follows
1. The limit switch actuator 6 is pressed through the plunger 42. When the actuator 6 is pressed from above, the push rod 4 in which the legs 6a of the actuator 6 are fitted into the vertical grooves 4d on both sides resists the spring force of the return spring 5 having a smaller spring force than the operation spring together with the actuator. Then move down. An arm at the tip of the push rod 4
4a is located above the push button 2a of the switch element 2, and the arm 4a pushes the push button 2a downward to turn on (close) the switch. When the actuator 6 is further pressed, the push rod 4 keeps pushing the push button 2a of the switch element 2, and the leg portions 6a at both ends of the actuator 6 slide down the vertical grooves 4d on both side surfaces of the push rod 4, and only the actuator 6 is moved. Moves downward against the spring force of the operation spring 7 to absorb the overstroke. The operation spring 7 inserted between the push rod 4 and the actuator 6 in this manner absorbs the overstroke and sufficiently secures the stroke of the actuator 6.

When the actuator of the lever 40 returns to its original position, the limit switch slides the leg 6a of the actuator 6 upward in the vertical groove 4d by the spring force of the operation spring 7, and the actuator 6 is pushed upward. Then, the push rod 4 and the operation spring 7 are pushed upward by the spring force of the return spring 5, and the limit switch returns to the original state.

[0015]

According to the present invention, the limit switch comprises a case, a switch element mounted on the case, a push rod for opening and closing the switch element,
The structure of the limit switch can be simplified by dividing the pressing switch into a return movable portion including a return spring and an actuator, and a stroke absorbing portion including an operation spring that absorbs an overstroke when the actuator is pressed. In addition, assembling of the limit switch is completed when the push rod, the return spring, the operation spring, and the actuator are sequentially assembled in the case, so that an effect that the assembling work can be easily performed is obtained.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a limit switch showing one embodiment of the present invention.

FIG. 2 is a front view of the limit switch of the present invention.

FIG. 3 is a plan view of FIG. 1;

FIG. 4 is a diagram showing an assembled state of an actuator on a push rod.

FIG. 5 is a view showing an assembled state of an actuator to a push rod according to another embodiment.

FIG. 6 is a longitudinal sectional view of a roller lever type limit switch of the present invention.

FIG. 7 is a front view showing a state where a cover is removed in FIG. 6;

FIG. 8 is a partial cross-sectional front view of a limit switch showing a conventional example.

[Explanation of symbols]

 1 Case 1a Notch 1b Upper Opening 1c Concave 1d Front Opening 1e Rear Opening 2 Switch Element 2a Push Button 4 Push Rod 4a Arm 4b Concave 4c Protrusion 4d Vertical Groove 4e Projection 5 Return Spring 6 Actuator 6a Leg 6a Projection 6c Hole 7 Operation spring

Claims (2)

(57) [Claims] 1. A case having an upper opening, a front opening and a rear opening opening in a direction perpendicular to the upper opening, and a case in which the respective openings communicate with each other, and a case attached to the front side of the case. And a switch element part having a push button of the switch element protruding into the front opening, and a contact part formed on the inner wall of the case connected to the front opening through the rear opening of the case and connected to the upper opening. It is positioned in contact with the contact part formed on the inner wall of the case,
A push rod slidable in a direction orthogonal to a line connecting the front opening and the rear opening and operating to open and close the switch element, and the push rod inserted between the push rod and the case is inserted into the upper opening of the case. A return spring that presses against a continuous contact portion to form a gap between the push rod and the inner wall surface opposite to the upper opening of the case, is inserted from the upper opening of the case, and comes off in the direction of the rear opening of the push rod. A pressing movable portion formed of an actuator that is fitted into the push bar so as to perform a stop and slides in the same direction as the push bar, and is inserted between the actuator and the push bar, and is opposite to the upper opening of the push bar and the case. An operating spring having a contraction dimension larger than a gap between the inner wall of the actuator and a spring having a larger force than the return spring and absorbing an overstroke when the actuator is pressed. Limit switches, characterized by comprising a stroke absorbing portion. 2. The limit switch according to claim 1, wherein the push rod has a vertical groove on both side surfaces, and the actuator has a substantially U-shape and has both legs fitted into the vertical groove. Limit switch.