JPH05205562A - Push button switch - Google Patents

Abstract

PURPOSE:To provide a cheap push button switch without losing reliability by incorporating a conductive rubber and simply and surely installing a fixed contact or metal terminal to a frame without use of insert forming which causes a cost up. CONSTITUTION:A rubber molding 2 having conductive rubber portions 9, 10 is mounted on the inner surface of a frame 1 to make the conductive rubber portion 9, 10 into fixed contacts and also fixed at the frame 1 in such a state that metal terminals 3, 4 are pressure-welded to the conductive rubber portions 9, 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a push button switch for switching on and off by contacting and separating a movable contact with a fixed contact conducted to a metal terminal, and more particularly to a mounting structure for the fixed contact and the metal terminal. ..

[0002]

2. Description of the Related Art A push button switch of this type is usually constructed by a casing having a fixed contact on the inner bottom surface and a metal terminal protruding to the outside, a movable contact which is brought into contact with and separated from the fixed contact, and this movable contact. In order to attach a fixed contact and a metal terminal to the housing, the conventional product has a housing formed by inserting a press-formed hoop-shaped metal plate into the housing. That is, of the inserted metal plate, a portion exposed on the inner surface of the housing serves as a fixed contact, and a portion protruding to the outside of the housing serves as a metal terminal, so that the fixed contact and the metal terminal are connected. Continuity failure can be avoided and the strength of attachment to the case can be secured.

[0003]

However, if a metal plate pressed as in the above conventional product is inserted to form a housing, the initial cost of the hoop supply equipment and the like increases and the assembly line also becomes long. Therefore, there was a problem that the cost of the product was forced to increase.

The present invention has been made in view of the above problems of the prior art, and an object thereof is to provide an inexpensive push button switch which can easily and reliably attach a fixed contact or a metal terminal to a housing without performing insert molding. To provide.

[0005]

The above-mentioned object of the present invention is to mount a conductive rubber on the inner surface of a casing to make the conductive rubber a fixed contact and to press a metal terminal to the conductive rubber. This can be achieved by fixing it in the above state in the case.

[0006]

By utilizing the elastic force of the conductive rubber, the metal terminal can be easily fixed to the housing in a state of being pressed against the conductive rubber. Since it can be sandwiched between the metal terminal and the housing, insert molding is unnecessary. Further, the fixed contact made of conductive rubber can absorb the impact when the movable contact comes into contact.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the push button switch according to the present invention will be described below with reference to FIGS. Here, FIG. 1 is a cross-sectional view of the push button switch when it is not operated, FIG. 2 is a cross-sectional view of the push button switch when it is pushed, and FIG. 3 is a main part showing a mounting structure of a rubber molded product incorporated in the push button switch. FIG. 4 is a cross-sectional view, and FIG. 4 is a perspective view of an essential part showing a mounting structure of a metal terminal incorporated in the push button switch.

The push button switch shown in these figures has a housing 1 made of a synthetic resin material, a rubber molded product 2 mounted and fixed on the inner bottom surface of the housing 1, and bent into a substantially U-shape. A position facing the upper surface of the rubber molded product 2 with a pair of metal terminals 3 and 4 of which both ends are made of rectangular wire rods and protruded downward from the housing 1, and a flexible member formed by printing a conductive pattern on a resin film. The contact sheet 5 installed in the housing 1, the coil spring 6 that is disposed above the contact sheet 5 in the housing 1 and is elastically deformed including buckling, and the coil spring 6 is movable up and down with respect to the housing 1. When the stem 7 is pushed downward a predetermined stroke against the spring force of the coil spring 6, the coil spring 6 compressed by a predetermined amount buckles downward, The buckling portion 6a of the coil spring 6 is at the center of the contact sheet 5. The so that the push downward.

Here, as is apparent from FIG. 3, the rubber molded product 2 has an insulating rubber portion 8 made of silicon rubber and an insulating rubber portion 8 made of a conductive rubber material obtained by kneading silicon rubber with conductive powder. It is a molded product in which a pair of conductive rubber portions 9 and 10 arranged side by side on the insulating rubber portion 8 with the central portion interposed therebetween is integrated, and is a thin portion 9a of each conductive rubber portion 9 and 10. , 10a
The metal terminals 3 and 4 are press-contacted with each other. That is, the substantially U-shaped metal terminals 3 and 4 project downwardly of the housing 1 as shown in FIG. 4, with the central portions thereof pressed against the thin portions 9a and 10a of the conductive rubber portions 9 and 10. The metal terminals 3 and 4 attached to the housing 1 in this way are locked and fixed to the housing 1 by twisting the part to be twisted by about 90 degrees. , 10 are maintained in pressure contact with each other, and the rubber molded product 2
Both ends of itself are sandwiched between the metal terminals 3 and 4 and the housing 1. The terminal projecting portion 1a of the housing 1 in which the metal terminals 3 and 4 are projected to the outside is formed in a substantially V shape in order to prevent the flux from rising.

Further, although one end of the coil spring 6 which is an elastic buckling member is fixed to the stem 7, the other end is fixed although it is elastically contacted with the peripheral edge of the positioning protrusion 1b in the housing 1. The casing 1 supports the end portion in a non-fixed state. Therefore, when buckling, as shown in FIG.
The end portion of the coil spring 6 can rotate around the positioning protrusion 1b in a direction away from the housing 1. This ensures a large buckling action of the coil spring 6. The buckling portion 6a of the coil spring 6 which is buckled downward bends the central portion of the contact sheet 5 toward the rubber molded product 2 as shown in FIG. 2, so that the conductive pattern of the contact sheet 5 becomes conductive. The conductive rubber portions 9 and 10 that are in contact with the thick portions 9b and 10b of the conductive rubber portions 9 and 10 are electrically connected to each other through the contact sheet 5. That is, in this push button switch, the thick portions 9b and 10b of the conductive rubber portions 9 and 10 are used as fixed contacts, and the contact sheet 5 is used as a movable contact that contacts and separates both fixed contacts.

Furthermore, in the center of the bottom surface of the stem 7,
A buckling force projection 7a that comes into contact with the buckling portion 6a of the coil spring 6 at the time of descending operation is provided, and the buckling operation of the coil spring 6 is forcibly started by being pushed downward by this projection 7a. Is becoming

Reference numeral 11 in the drawing denotes a printed circuit board on which the push button switch is mounted, and the metal terminals 3 and 4 are soldered to the circuit pattern of the printed circuit board 11.

Next, the operation of the push button switch will be briefly described.

In the non-operating state shown in FIG. 1, the pair of conductive rubber portions 9 and 10 in the housing 1 are insulated from each other and thus kept in a switch-off state. Is pushed downward, the coil spring 6 buckles at the time of pushing for a predetermined stroke and a click feeling is generated. Immediately after that, as shown in FIG. 2, the contact sheet 5 pushed into the buckling portion 6a of the coil spring 6 Bends and abuts against the pair of conductive rubber portions 9 and 10,
Is conducted through the contact sheet 5, so that the switch is turned on. At this time, the operator can feel the switch-on by the click feeling transmitted to the fingers.

When the pushing operation force on the stem 7 is removed in the switch-on state, the buckled coil spring 6 returns to the state shown in FIG. The conductive rubber portions 9 and 10 are separated from each other and switched to the switch-off state, and the restoring force of the coil spring 6 causes the stem 7 to rise to the initial position along the housing 1.

As described above, according to the above-described embodiment, the metal terminals 3 and 4 are pressed against the conductive rubber portions 9 and 10 of the rubber molded product 2 mounted on the inner bottom surface of the casing 1, respectively, and the metal terminals 3 are pressed. , 4 are locked to the housing 1 by a simple twisting process, and when the metal terminals 3, 4 are fixed to the housing 1 in this way, the rubber molded product 2 can be automatically fixed at a predetermined position in the housing 1. Therefore, the fixed contacts (conductive rubber portions 9 and 10) and the metal terminals 3 and 4 can be attached to the housing 1 easily and reliably without performing insert molding that causes a cost increase, and a rubber molded product can be obtained. Since the elastic force of 2 is used, the conduction between the conductive rubber portions 9 and 10 and the metal terminals 3 and 4 is sure. Moreover, after fixing the rubber molded product 2 and the metal terminals 3 and 4 to the housing 1, the contact sheet 5, the coil spring 6 and the stem 7 are subsequently incorporated into the housing 1 to complete the product. The assembly process can be completed by one automatic assembly, and the assembly cost can be significantly reduced.

Further, in the above embodiment, since the conductive rubber portions 9 and 10 of the rubber molded product 2 are used as the fixed contacts, the rubber molded product 2 alleviates the impact when the coil spring 6 buckles. This has the advantage that it is possible to avoid sparks that may occur when metals are brought into contact with or separated from each other. Moreover,
In this rubber molded product 2, the distance between the pair of conductive rubber portions 9 and 10 can be regulated with high precision by the insulating rubber portion 8. When the pair of conductive rubber portions 9 and 10 are brought close to each other, In addition, since the insulation between the two can be secured, there is also an advantage that the space factor can be improved.

Furthermore, in the above embodiment, the contact sheet 5 is used.
Is installed in a position to cover the rubber molded product 2, so that dust can be prevented from entering the contact portion. Moreover, since the metal terminals 3 and 4 are not press-fitted into the housing 1, the scraps of the square wire stick to the contact portion. There is no fear, and therefore the contact portion has a structure that is unlikely to cause poor conduction or a short circuit accident.

In the above embodiment, the case where the metal terminals 3 and 4 are twisted and fixed to the housing 1 has been described, but the metal terminals may be fixed by heat-sealing part of the housing.

Further, in the above-mentioned embodiment, the push button switch with a click feeling for performing the on / off switching by utilizing the buckling operation of the coil spring is illustrated. However, the fixed contact made conductive with the metal terminal is provided on the inner surface of the housing. The present invention can be applied to all push button switches arranged in.

[0021]

As described above, according to the present invention in which the conductive rubber is used as the fixed contact and the metal terminal is pressed against the conductive rubber and fixed to the housing, the conductive rubber is elastic. Since it has a force, it has a reliable electrical connection with the metal terminal, and since the conductive rubber can be sandwiched between the metal terminal and the housing, the conductive rubber (fixed It is possible to easily and surely attach the contact point) and the metal terminal to the housing, and thus it is possible to provide an inexpensive push button switch without impairing reliability.
Further, since the fixed contact made of conductive rubber can absorb the impact when the movable contact comes into contact, it also has an effect of improving the operability and extending the life.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a push button switch according to an embodiment when it is not operated.

FIG. 2 is a cross-sectional view of the push-button switch when it is pushed.

FIG. 3 is a cross-sectional view of an essential part showing a mounting structure of a rubber molded product incorporated in the push button switch.

FIG. 4 is a perspective view of an essential part showing a mounting structure of a metal terminal incorporated in the push button switch.

[Explanation of reference symbols] 1 case 1a terminal protruding portion 2 rubber molded product 3.4 metal terminal 5 contact sheet 6 coil spring 7 stem 8 insulating rubber portion 9, 10 conductive rubber portion (fixed contact)

Claims (2)

[Claims] 1. A housing made of a synthetic resin material, a fixed contact disposed on an inner surface of the housing, a metal terminal electrically connected to the fixed contact and protruding to the outside of the housing, and the fixed member. In a push-button switch having a movable contact that contacts and separates from a contact, a conductive rubber is mounted on the inner surface of the casing to make the conductive rubber the fixed contact, and the metal terminal is used as the conductive rubber. A push button switch characterized in that it is fixed to the above-mentioned housing in a pressed state. 2. The metal terminal according to claim 1, wherein the metal terminal is made of a rectangular wire, and a portion of the metal terminal protruding to the outside of the housing is locked to the housing by twisting. Push button switch characterized by.