JPH02260338A - Pushbutton switch - Google Patents

Abstract

PURPOSE:To obtain a pushbutton switch at low cost by providing such a constitution as making a press plate serve as a stem. CONSTITUTION:On the inner bottom surface of a case 11, fixed contacts 12, 13 are formed by insert molding, and a curved reversing spring 14 is laid on the both side fixed contacts 12. A water-proofing and dust-preventing sheet 15 consisting of polyimide is mounted on the upper surface of the case by a viscous material, and a press plate 16 is laminated and mounted on the viscous material. The press plate 16 is formed of a support part 19 having an opening 17 in the center part and engaging claws 18 on a pair of the side surfaces, a pair of bending parts 20 extending from one end of the support part 19 and narrowly formed, and a plane part 22 provided on the bending part 20 top end and having a projection 21 facing the curved reversing spring 14.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a push button switch used in TVs, VTRs, cassette decks, etc.

[Conventional technology]

A conventional push button switch of this type will be explained with reference to FIG.

In the figure, reference numeral 1 denotes a case, and a fixed contact 2.3 is formed by insert molding on the inner bottom surface of the case 1, and a dome-shaped movable contact 4 that can be bent and reversed is arranged on the fixed contact 2. A stem 5 is placed on the movable contact 4, and a holding plate 6 is attached to the case to prevent the stem 5 from coming off above the case 1. A waterproof and dustproof sheet 7 is interposed between the case 1 and the holding plate 6.

[Problem to be solved by the invention]

However, in order to obtain a waterproof structure for this type of push button switch, it is conceivable to attach the seat 7 directly to the movable contact 4 without placing the stem 5 on it, but in this case, a device such as a cassette deck etc. Since the movable contact 4 is directly pressed by the key top of the operation panel via the sheet 7 when installed in the
If misalignment occurs, there is a problem that the pressing feeling of the movable contact 4 becomes poor or the movable contact 4 is not pressed reliably, so the structure of the conventional example shown in FIG. 5 has been adopted.

However, in this conventional push button switch, 1.
Since the stem 5 made of synthetic resin or the like is placed on the movable contact 4, there is a problem in that it is not possible to further reduce the thickness.

Therefore, the present invention has been made to solve the above-mentioned conventional technical problems, and an object of the present invention is to obtain a thin push button switch that can reliably switch the contacts.

[Means to solve the problem]

In order to solve the above technical problems, the present invention has a fixed contact formed on the inner bottom surface of the case, a movable contact arranged to face the fixed contact, a presser plate attached to the upper surface of the case, and a fixed contact formed on the inner bottom surface of the case. In a push button switch having a sheet interposed between the presser plate and the presser plate, the presser plate has a support portion having a through hole, and a protrusion extending from the support portion and capable of pressing a movable contact located in the through hole. It is composed of a plate portion having.

(Function) Therefore, in the present invention, when a pressing operation force is applied to the flat plate portion of the presser plate, the bent portion is elastically deformed and the protrusion of the plate portion reverses the reversing spring, and when the pressing operation force is removed, the bent portion automatically deforms. The elasticity allows the stem to return to its intended position, reducing the number of parts and weight compared to a structure with a resin stem.Also, since a protrusion is formed on the lower surface of the flat plate, push button switches and key tops can be easily removed. Even if a positional shift occurs between the two, the movable contact will always be pressed in a constant manner.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view of the main parts of the push button switch, FIG. 2 is a plan view of the push button switch, FIG. 3 is a developed view of the holding plate, and FIG. 4 is a side view of the holding plate.

In the figure, reference numeral 11 denotes a case, and fixed contacts 12 and 13 are formed on the inner bottom surface of the case 11 by insert molding, and curved reversal springs 14 are placed on the fixed contacts 12 on both sides.

A waterproof and dustproof sheet 15 made of polyimide or the like is attached to the upper surface of the case 11 with an adhesive, and a presser plate 16 is laminated and attached on the adhesive. Presser plate 1
6 has an opening 17 in the center and engaging claws 18 on a pair of sides.
a pair of bent portions 20 extending from one end of the supporting portion 19 and formed narrowly; The flat plate part 22 is provided with a protrusion 21. This protrusion 21 is formed by punching, and is placed on the curved reversing spring 14 via the waterproof anti-shock sheet 15 in the initial state.

Also, when attaching the holding plate 16 to the case 11,
The protrusion 22 provided on the side wall of the support portion 19 is fixedly attached to the recess 23 of the case 11.

With the above configuration, when the key top provided on the operation panel is pressed, the flat plate part 22 of the holding plate 16 is pressed by the key top, and the curved reversing spring 14 is activated by the protrusion 21 of the flat plate part 22 via the waterproof and dustproof sheet 15. When the upper end of the curved reversing spring 14 comes into contact with the central fixed contact 13, the switch becomes conductive.

Then, by releasing the pressure on the key top, the curved reversing spring 14 returns to the fixed contact 13 due to its own elastic return force.
When you move away from the camera, the switch turns OFF.

At this time, since the flat plate part 22 is formed relatively large, even if there is some positional deviation between the key top and the push button switch, a part of the upper surface of the flat plate part 22 is pressed and the protrusion on the lower surface of the flat plate The push button switch will not feel bad when pressed.

In addition, a plurality of recesses 23 are provided in the side wall of the case 11, and after bending the curved portion 24 of the holding plate 16 in the side direction from the dotted line position in FIG. is installed. Therefore, the presser plate 16
When installing, no engaging protrusions are provided on the case 11 side, and the protrusions 22 of the holding plate 16 are locked into the recesses 23 of the case 11, so the size is reduced due to the lack of engaging protrusions. can be achieved.

〔Effect of the invention〕

Therefore, in the present invention, since the holding plate is configured to also serve as a stem, a low-cost push button switch can be obtained. Furthermore, since the movable contact is pressed by the protrusion on the lower surface of the flat plate, the contact can be pressed reliably.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the main parts of the push button switch of the present invention, FIG. 2 is a plan view of the push button switch of the present invention, FIG. 3 is a developed view of the presser plate of the present invention, and FIG. A side view of the holding plate and FIG. 5 are sectional views of essential parts of a conventional push button switch. 11...Case, 12.13...Fixed contact, 14.
... Movable contact (curved inversion spring), 15 ... Sheet (dustproof and waterproof sheet), 16 ... Holding plate, 17 ... Through hole,
21...Protrusion, 22...Plate part.

Claims (1)

[Claims] A push button switch consisting of a fixed contact formed on the inner bottom of the case, a movable contact placed to face the fixed contact, a holding plate attached to the top of the case, and a sheet interposed between the case and the holding plate. In the push button switch, the presser plate is constituted by a support portion having a through hole, and a plate portion extending from the support portion and having a protrusion capable of pressing a movable contact located within the through hole. .