JPH0411314Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Field of Application) The present invention relates to a small switch that requires an extremely small installation space and has low and stable contact resistance during conduction.

(Conventional technology) Turns on/off by operating the electrical contacts for the keyboard of OA equipment or the screen opening/closing lid of a small LCD television receiver.
Conventionally, a small micro switch has been used as a power switch that is turned off, and also a power switch that is turned on and off when the card radio's earphones are connected and separated.

As shown in FIG. 6, the conventional micro switch 1 has one end of a tension member 2 fixed to a fixed base 3, the other end being a free end, and a movable contact 4 provided at the tip of the tension member 2. The other end of the compression member 5, which has one end fixed near the section, is locked in a compressed state by a receiver 6. Furthermore, the movable contact 4 is brought into contact with one of the two fixed contacts 8 and 9 by a snap action by the tension member 2 and the compression member 5 in response to the external force 7 applied from a direction substantially perpendicular to the tension member 2. is configured to allow

Since such a conventional micro switch 1 switches the contacts by a snap action, it is possible to reliably interrupt and conduct the electric circuit.
It is widely used in various electronic devices.

(Problem to be solved by the invention) Regarding the above-mentioned micro switch 1, a small one is also available, but in order to switch the contact point with a snap action, the leaf spring of the tension member 2, etc. The length l in the lateral direction with respect to the pressing direction of the external force 7 greatly influences the stroke of the movable contact 4. Therefore, if the tension member 7 etc. is shortened in order to shorten the lateral length l with respect to the external force 7, the movable contact 4
The snap action operation and contact with the fixed contacts 8 and 9 cannot be ensured, and the reliability of electrical circuit interruption and continuity is reduced. Therefore, the length of the tension member 2, etc. cannot be reduced much, and the microswitch 1 requires a larger installation space in the plane orthogonal to the pressing direction. As a result, this becomes a factor that hinders the miniaturization of devices, and there is also the problem that the switches cannot be arranged with a sufficiently high packaging density.

The purpose of this invention was made in view of the above-mentioned circumstances, and it is possible to minimize the installation space on a surface perpendicular to the pressing direction, absorb variations in pressing operation distance, and reduce contact resistance during conduction. The purpose is to provide a small switch that is stable.

(Means for solving the problem) In order to achieve the above object, the small switch of the present invention has a press-operated insulating member slidably disposed at the front of the insulating cylinder so as not to slip out forward. A bottomed hole is bored in this press-operated insulating member facing forward from the rear end, a movable contact is movably inserted into the bottomed hole so as not to slip out backward, and a coil spring is inserted so that the movable contact is moved backward. A connector pin is fixed at the rear of the insulating cylinder so that the plunger can be retracted against the elastic force by bringing the tip of the plunger into contact with the movable rear end. At the same time, a conductive washer is fixed in an insulated state with respect to the connector pin while facing away from the movable contact, and the conductive washer is provided with a tapered and flexible inclined contact portion toward the movable contact. has been done.

(Function) Since all the constituent members such as the press-operated insulating member and the movable contact that move by the press operation are incorporated into the insulating cylinder, the installation space in the plane perpendicular to the press-operation direction is extremely small. In addition, the press-operated insulating member is pressed against the elasticity of the connector pin to bring the movable contact into contact with the conductive washer, and the conductive washer is provided with a tapered and flexible inclined contact portion. When the movable contact contacts the conductive washer and is further pressed, a component force perpendicular to the pressing direction acts on the inclined abutting portion due to the tapered slope, and the contact point between the movable contact and the inclined abutting portion is displaced. Therefore, the contact point is cleaned by friction and the contact resistance is small and stable.

(Example) Hereinafter, an example of the present invention will be described with reference to FIGS. 1 to 4. FIG. 1 is a longitudinal cross-sectional view of one embodiment of the small switch of the present invention, FIG. 2 is a perspective view of the conductive washer shown in FIG. 1, and FIG.
4 is a side view from the rear of the figure, and FIG. 4 is a diagram illustrating the operation of the small switch of FIG. 1.

In the figure, the small switch has an outer diameter of 6 mm, for example.
The front end opening of the insulating cylindrical body 10 made of insulating resin and having a length of 13 mm is narrowed to form a small hole 11, and the operating rod 12 is projected forward from this small hole 11 to form a press-operated insulating member made of insulating resin. 13 is slidably disposed within the insulating cylindrical body 10 so as not to slip out forward. A bottomed hole 14 is formed forward from the rear end surface of the press-operated insulating member 13. A metal guide pipe 16 having a small hole 15 for preventing slippage formed at the rear end by caulking or the like is press-fitted into the bottomed hole 14 and fixed thereto. Further, a movable contact 17 made of a conductive material is inserted into the guide pipe 16 through a small hole 15 for preventing it from slipping out so as to be movable in the front-rear direction. The coil spring 18 is contracted within the bottomed hole 14 so as to elastically urge the movable contact 17 rearward. The rear end of the movable contact 17 is enlarged into a flange shape, and a truncated conical recess 19 is formed in the rear end surface. Further, at the rear part of the insulating cylinder 10, the inner diameter is partially enlarged from the rear end surface toward the front, and a stepped part 20 is formed. and a contact pin 21 from which the plunger can retreat against elasticity;
It is fixed to an insulating bushing 22 by insert molding, and a metal cylinder 23 made of a conductive material is placed over this insulating bushing 22. A step 24 is formed at the front end of the metal cylinder 23, and an annular conductive washer 25 is press-fitted into the step 24 and is insulated from the contact pin 21. In addition, wedge-shaped projections 26, 26 are provided in the middle part of the metal cylinder body 23 and become higher toward the rear.
... are provided to protrude outward, and a protruding ring 27 is formed inward by caulking and fixed to the insulating bushing 22. Furthermore, the metal cylindrical body 23
Terminals 28, 28 are formed by uncut portions at the rear portions. This assembly of the contact pin 21, insulating bushing 22, metal cylinder 23, and conductive washer 25 is press-fitted from the rear of the insulating cylinder 10 until the conductive washer 25 comes into contact with the stepped portion 20. Here, the wedge-shaped protrusions 26, 26... bite into the inner wall of the insulating cylinder 10 and are prevented from coming off, and the tip of the plunger of the contact pin 21 is connected to the movable contact 1.
It abuts against the rear end surface of 7. In addition, the conductive washer 25
A plurality of protrusions 29, 29, . . . are cut and raised to form a tapered and flexible inclined contact portion that tapers toward the movable contact 17. This protrusion 29,2
The free ends of the movable contacts 17 face the tapered surfaces of the recesses 19 on the rear end surfaces of the movable contacts 17. In addition, contact pin 2
The elasticity that presses the plunger 1 is set to be weaker than the elasticity of the coil spring 18.

In this configuration, first, if the operating rod 12 is not pressed, the movable contact 17 is biased forward due to the elasticity of the connector pin 21 that presses the plunger forward, and the movable contact 17 is separated from the conductive washer 25. . For this reason, contact pin 21
from the terminal 2 via the conductive washer 25 and the metal cylindrical body 23.
The circuit leading to 8 and 28 is cut off.

When the operating rod 12 is pressed against the elasticity of the contact pin 21, the movable contact 17 comes into contact with the conductive washer 25, and the circuit from the contact pin 21 to the terminals 28, 28 is connected via the movable contact 17. is conductive. Further, when the operating rod 12 is pressed, the coil spring 18 is compressed, and the movable contact 17 is brought into strong elastic contact with the conductive washer 25, ensuring reliable conduction, and variation in the pressing operation distance of the operating rod 12. is absorbed. Therefore, a switch function is obtained in which the circuit between the contact pin 21 and the terminals 28, 28 is made conductive by pressing the operating rod 12.

Here, the movable contact 17 is connected to the protruding piece 2 of the conductive washer 25.
9, 29..., the movable contact 17 is slightly tilted due to uneven elasticity of the coil spring 18 that elastically urges the movable contact 17 backward, and the movable contact 17 is slightly tilted, and the movable contact 17 is slightly tilted by the plural protrusions 29, 29... They do not contact each other at the same time, but at different times. For this reason, sparks are generated between the protrusion 29 and the movable contact 17 that come into contact with each other first, and the contact area becomes dirty with carbon etc. and the surface becomes rough, which tends to increase the contact resistance. The third contact piece 29,2
No spark occurs at 9. Furthermore, due to non-uniformity of elasticity of the coil spring 18, the protrusion 29 that comes into contact with the coil spring 18 at first is almost constant. Therefore, the contact portions of the second and third protruding pieces 29, 29, .

Further, since the free ends of the tapered protruding pieces 29, 29... contact the tapered surface of the truncated conical recess 19 of the movable contact 17, the movable contact 17 and the protruding pieces 29, 2
A component force perpendicular to the pressing direction acts on the contact points P of the recesses 9 , and the contact points P are shifted on the tapered surface of the recess 19 . Therefore, the contact point P is cleaned by the friction caused by the movement of the contact point P, and a small and stable contact resistance is maintained.

Further, the plunger of the connector pin 21 is always in elastic contact with the movable contact 18 facing the movable contact 18, and the contact resistance between the movable contact 17 and the connector pin 21 is small and stable compared to sliding contact or the like.

FIG. 5 is a partial vertical sectional view of another embodiment of the small switch of the present invention. In FIG. 5, members that are the same or similar to those in FIG. 1 are given the same reference numerals and redundant explanations will be omitted.

In the small switch shown in FIG. 5, a metal cylinder 23 and a conductive washer 25 are integrally formed of a flexible conductive material. Then, the conductive washer 25 is attached to the movable contact 1.
The inclined contact portion is formed in a tapered shape toward 7. Further, the rear end portion of the movable contact 17 is enlarged into a flange shape, and a plurality of protrusions 30 are provided on the rear end surface corresponding to the inclined contact portion of the conductive washer 25.
30... are provided.

In this configuration, when the operating rod 12 is pressed and the protrusions 30, 30... of the movable contact 17 come into contact with the conductive washer 25, the slight inclination of the movable contact 17 causes the protrusions 30, 30... to simultaneously contact the conductive washer 2.
It does not contact the inclined contact portion of No. 5, but contacts each of them at a time lag. Therefore, even if a spark occurs on the first protrusion 30 that comes into contact, the other protrusions 30, 3
No spark is generated at 0.

Furthermore, the protrusions 30, 30, . Therefore, even if the contact points become contaminated by sparks or the like, they are cleaned by friction, and a small and stable contact resistance is maintained.

(Effects of the invention) As explained above, according to the small switch of the present invention, all the constituent members are built into the insulating cylinder, and the switch requires an extremely small installation space in the plane orthogonal to the pressing operation direction. Can be configured. Therefore, the space required to install the switch in the device may be small, and the device can be made smaller and the switches can be mounted in a higher density. Further, even if the pressing operation distance varies, it is sufficiently absorbed, stable conduction is obtained, and the mechanical life of the switch is long. Furthermore, the contact point between the movable contact and the conductive washer is cleaned by friction, ensuring reliable electrical continuity, and maintaining a small and stable contact resistance, making it particularly suitable for use as a switch that handles small currents. play.

[Brief explanation of drawings]

1 is a longitudinal cross-sectional view of one embodiment of the small switch of the present invention, FIG. 2 is a perspective view of the conductive washer shown in FIG. 1, and FIG. 3 is a view from the rear of FIG. 1. FIG. 4 is a diagram explaining the operation of the small switch of FIG. 1, and FIG. 5 is a partial vertical cross-sectional view of another embodiment of the small switch of the present invention;
FIG. 6 is a diagram showing the operating principle of a conventional microswitch. 10... Insulating cylindrical body, 13... Press operation insulating member, 14... Bottomed hole, 17... Movable contact, 18...
...Coil spring, 21...Connector pin, 2
5... Conductive washer, 29... Projection piece.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A press-operated insulating member is slidably disposed at the front of the insulating cylinder so as not to slip out forward, and a bottomed hole is formed in the press-operable insulating member from the rear end. A movable contact is movably inserted into the bottomed hole so as not to slip out backward, and a coil spring is contracted so as to elastically bias the movable contact rearward. A connector pin whose plunger is capable of retracting against elasticity is fixed to the rear part of the insulating cylindrical body by bringing the tip of the plunger into contact with the rear end of the movable contact, and a conductive washer is placed facing away from the movable contact. 1. A small switch, characterized in that the conductive washer is fixed in an insulated state from the connector pin, and the conductive washer is provided with a tapered and flexible inclined contact portion toward the movable contact. (2) The small switch according to claim 1, wherein the inclined contact portion is formed by a plurality of protrusions cut and raised from the conductive washer.