JPH0411312Y2 - - 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. 4, 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. 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 with respect to the plane orthogonal to the pressing direction. As a result, this became a factor that hindered miniaturization of the device, and there was also the problem that the switches could not 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 formed in this pressing operation 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 first coil spring is inserted into the movable contact. A contact is contracted so as to be elastically biased toward the rear, a hole is bored in the movable contact toward the front from the rear end, and a hole is formed in the rear of the insulating cylindrical body,
A terminal member is fixed so that the front part is slidably inserted into the hole, and a conductive washer is fixed in an insulated state from the terminal member so as to face away from the movable contact, and the movable contact and the conductive washer A plurality of protrusions are provided on either one of the opposing surfaces of the first
A second coil spring whose elasticity is weaker than that of the coil spring is contracted so as to elastically urge the movable contact forward.

(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. Further, when the push-operation insulating member is pressed against the elasticity of the second coil spring to bring the movable contact into contact with the conductive washer, and the push-operation insulator is further pushed, the movable contact is moved by the elasticity of the first coil spring. Since it comes into elastic contact with the conductive washer, stable conduction can be obtained regardless of variations in the pressing operation distance. Furthermore, since multiple protrusions are provided on one of the facing surfaces of the conductive washer and the movable contact, when the movable contact contacts the conductive washer, the inclination of the movable contact causes each of the multiple protrusions to have a certain amount of time. Contact is off-center. Therefore, even if a spark is generated in the protrusion that comes into contact with the first protrusion, sparks will not be generated in the protrusion that comes into contact with the second and subsequent ones, 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 3. FIG. 1 is a longitudinal sectional view of one embodiment of the small switch of the present invention, FIG. 2 is a front view of the conductive washer shown in FIG. 1, and FIG.
It is a side view from the rear of a figure.

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 retaining caulking ring 15 formed in its intermediate portion 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 so as to be movable in the front and back direction so as to prevent it from slipping out rearward by a retaining caulking ring 15. This movable contact 1
The rear end portion of 7 is enlarged into a flange shape, and a first coil spring 19 is installed between this flange-like portion 18 and the rear end surface of the press operation insulating member 13 so as to elastically bias the movable contact 17 rearward. will be reduced. A hole 21 having a stepped portion 20 is bored in the movable contact 17 from the rear end face toward the front. Further, at the rear part of the insulating cylinder 10, the inner diameter is partially enlarged from the rear end face toward the front to form a stepped portion 22, and an annular conductive washer 23 is inserted up to this stepped portion 22. A terminal member 24 whose front part is slidably inserted into a hole 21 bored in the movable contact 17 is fixed to an insulating bushing 25 by insert molding, and terminals 26, 26 are formed on this insulating bushing 25 by leaving uncut parts. A metal cylindrical body 27 made of a conductive material is covered. And the second coil spring 2
8 is inserted into the hole 21 of the movable contact 17, and the insulating bush 25 is covered with a metal cylinder 27 so that the front part of the terminal member 24 is inserted into the hole 21.
is press-fitted into the insulating cylinder 10 until the front end of the metal cylinder 27 comes into contact with the conductive washer 23 . Here, the conductive washer 23 and the terminal member 24 are insulated. The elasticity of the second coil spring 28 is made weaker than that of the first coil spring 19. Further, a plurality of protrusions 29 , 29 , 29 are provided on the conductive washer 23 toward the movable contact 17 . Furthermore, a bottomed hole 30 is drilled from the rear side of the insulating cylinder 10 through the metal cylinder 27 to reach the insulating bushing 25, and a fixing pin 31 is press-fitted into the bottomed hole 30, and the insulating cylinder 10 is Insulation bushing 2
5 is fixed.

In this configuration, first, if the operating rod 12 is not pressed, the movable contact 17 is biased forward by the elasticity of the second coil spring 28, and the movable contact 17 is separated from the conductive washer 23. Therefore, the circuit from the terminal member 24 to the terminals 26, 26 via the conductive washer 23 and the metal cylindrical body 27 is interrupted.

When the operating rod 12 is pressed against the elasticity of the second coil spring 28, the movable contact 17 comes into contact with the conductive washer 23, and the movable contact 17 is interposed between the terminal member 24 and the terminals 26, 26. The circuit to is made conductive. Further, when the operating rod 12 is pressed, the first coil spring 19 is compressed, and the movable contact 17 is brought into strong elastic contact with the conductive washer 23 to ensure reliable conduction. Dispersion in distance is absorbed. Therefore, a switch function is obtained in which the circuit between the terminal member 24 and the terminals 26, 26 is made conductive by pressing the operating rod 12.

Here, the movable contact 17 is connected to the protrusion 2 of the conductive washer 23.
9, 29, 29, the movable contact 1
The movable contact 17 is slightly tilted due to uneven elasticity of the first coil spring 19 that elastically biases the coil spring 7 backward, and the movable contact 17 is slightly tilted, and the movable contact 17 is not applied to the plurality of protrusions 29 at the same time but at different times. and touch it.
For this reason, the protrusion 29 and the movable contact 1 that come into contact first
7, and the contact area becomes dirty with carbon etc. and the surface becomes rough, which tends to increase the contact resistance. However, sparks occur between the second and third protrusions 29 and 29 that come in contact with each other. do not have. Furthermore, due to non-uniform elasticity of the first coil spring 19, the projection 29 that comes into contact with the first coil spring 19 is almost constant. Therefore, the contact portions of the second and third protrusions 29, 29 that come into contact do not get dirty or rough, and there is no increase in contact resistance, and a small and stable contact resistance is maintained during conduction.

In the above embodiment, the first coil spring 19 is compressed between the rear end surface of the press-operated insulating member 13 and the flange-shaped portion 18 of the movable contact 17; The movable contact 17 may be compressed between the bottom of the movable contact 17 and the front end surface of the movable contact 17. Similarly, the second coil spring 28 may be compressed between the rear end surface of the movable contact 17 and the insulating bush 25. Further, the conductive washer 23 and the metal cylindrical body 27 may be formed integrally. Furthermore, the plurality of protrusions 29, 29, 29 provided on the conductive washer 23 may be provided on the movable contact 17, as long as they are provided on at least one of them.

(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 resistance does not increase due to sparks, and a small and stable contact resistance is maintained, making it particularly suitable as a switch that handles small currents.

[Brief explanation of the drawing]

1 is a longitudinal sectional view of one embodiment of the small switch of the present invention, FIG. 2 is a front view of the conductive washer shown in FIG. 1, and FIG. 3 is a view from the rear of FIG. 1. FIG. 4, which is a side view, is a diagram showing the operating principle of a conventional microswitch. 10... Insulating cylinder, 13... Press operation insulating member, 14... Bottomed hole, 17... Movable contact, 19...
...First coil spring, 21... Hole, 23...
...Conductive washer, 24...Terminal member, 29...Protrusion,
28...Second coil spring.

Claims (1)

[Scope of utility model registration request] A press-operated insulating member is slidably disposed at the front of the insulating cylinder so that it does not slip out forward, and a bottomed hole is bored in the press-operated insulating member toward the front from the rear end. A movable contact is movably inserted into the hole so as not to slip out backward, a first coil spring is contracted to elastically bias the movable contact rearward, and the hole is inserted into the movable contact from the rear end. A terminal member is fixed to the rear part of the insulating cylinder so that the front part is slidably inserted into the hole, and a conductive washer is opposed to the movable contact apart from the movable contact. Fix it in an insulated state with the terminal member,
A plurality of protrusions are provided on one of the facing surfaces of the movable contact and the conductive washer, and a second coil spring having a lower elasticity than the first coil spring is elastically biased toward the front of the movable contact. A small switch characterized by a compact structure.