JPH0628752Y2 - Spring member for push button switch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a spring member for a push button switch used in a keyboard of a computer or the like.

<Prior Art> A large number of push button switches are used in computer keyboards and the like, and usually have a structure in which a push button that is given a restoring force by a metal spring provided inside is fitted into a hole in a board. However, this structure has many partial points,
The structure is complicated and the cost tends to be high. Recently, so-called rubber springs have been used instead of metal springs, and the number of parts can be reduced to some extent. This rubber spring is formed by molding a rubber or a polymer resin material having elasticity into a dome shape or a shape similar thereto, for example, an inverted cup shape to form a spring portion.

<Problems to be solved by the invention> However, even in the case of such a rubber spring, in order to fix the rubber spring in a predetermined position, a fixing member such as a frame material for pressing the base portion of the rubber spring, and the number of man-hours for fixing are fixed. is necessary. There is also one in which the spring portion and the substrate supporting the spring portion are integrally formed, but when the flexibility of the spring portion is tried to be secured, the rigidity of the substrate is insufficient, and another pressing member is required.

This invention has been made in view of this point, and an object thereof is to obtain a spring member for a push button switch which does not require a separate member for fixing and has a sufficient spring action.

<Means for Solving the Problems> In order to achieve the above-mentioned object, in the present invention, a thin spring portion having a dome shape or a shape similar to this, which is pressed from the outside by a separate push button, and the spring. A mounting substrate having a predetermined rigidity and a thickness greater than that of a spring portion supporting the spring portion is formed by an integrally molded product of a polymeric resin material having elasticity, and the spring portion is provided with a plurality of vertical slits. ing.

As the elastic polymer resin material, a thermoplastic elastomer can be used, and it is particularly preferable to use a thermoplastic elastomer having a Shore hardness of 40D to 55D.

<Operation> By making the mounting board thicker than the spring part, the required rigidity can be obtained, and the keyboard can be constructed simply by mounting it on the circuit board on which the required circuit is formed. No pressing member is required. Even if a material having a relatively high hardness is used to increase the rigidity of the mounting substrate, the spring portion has a thin wall and a plurality of vertical slits are provided. Part is obtained.

Further, when a thermoplastic elastomer is used as the resin material, good moldability and durability can be obtained, and particularly, the Shore hardness is 40D.
In the case of using one of 55 to 55D, it becomes easy to achieve both the rigidity of the substrate and the flexibility of the spring portion.

<Example> Next, one example shown in the drawings will be described. FIG. 1 is a sectional view showing the structure and operation, FIG. 2 is a plan view, and FIG. 3 is a perspective view.

In the figure, reference numeral 1 denotes a spring member formed by integrally molding a thin spring portion 11 and a thick substrate 12 supporting the thin spring portion 11. The spring portion 11 is formed so as to cover the round hole 13 of the substrate 12, and has a dome shape or an inverted cup shape similar to that conventionally known,
In this embodiment, the lower half 11a has a cylindrical shape and the upper half 11b has a truncated cone shape, and the inner surface has a cylindrical pressing protrusion 14.
Are projected downward, and a plurality of (four in the embodiment) vertical slits 15 are formed from the lower end of the lower half 11a to the upper end of the upper half 11b. As a result, the spring portion 11 is in a state of being divided into four substantially spring-shaped spring pieces 16. Further, the board 12 has a shallow U-shape, and fixing claws 17 are projected downward at important points on both side pieces. Mounted on the board.

2 is a push button, which is a guide claw 21 provided at the lower edge of the periphery.
Is inserted into the guide hole 18 of the substrate 12, and the protrusion 22 on the inner surface is attached to the substrate 12 in a state of abutting against the upper surface of the spring portion 11. When the push button 2 is pushed, the spring piece 16 of the spring portion 11 is deformed and the pushing projection 14 is pushed down as shown in FIG. 1 (b), and at the tip thereof, a flexible electrode provided on a circuit board, for example. The film 3 is pressed. When the pushing operation of the push button 2 is stopped, the shape of FIG. 1 (a) is restored by the restoring force of the spring portion 11, and a predetermined opening / closing operation is performed. The type of the switch opened and closed by such an operation is arbitrary, and the present invention can be applied to various switches.

The shape and thickness of the spring portion 11 and the longitudinal slits 15 provided in the spring portion 11 provide appropriate repulsive force and restoring force when the push button 2 is pressed as described above and a desired stroke is obtained. The size and number of are selected according to the hardness of the resin material. Further, the thickness of the substrate 12 is also selected according to the hardness of the resin material so that a desired rigidity can be obtained and the keyboard can be configured only by attaching the fixing claw 17 to the circuit substrate.

Further, a polymer resin having elasticity is used as the material of the spring member 1. However, the silicone rubber that is often used in conventional rubber springs is not preferable because it has a relatively low hardness, and a material having an appropriate hardness can be obtained. Moreover, in consideration of moldability and durability, the thermoplastic elastomer is most suitable. Specifically, for example, a crystalline thermoplastic polyester elastomer commercially available from Toray-Dupont Co., Ltd. under the name of “HYTREL” can be used, and particularly those having a relatively high Shore hardness of 40D to 55D can be used. When used, good results are obtained in which the rigidity of the substrate and the flexibility of the spring portion are compatible. An example of the dimensions of each part in the illustrated shape at this time is shown. When the diameter of the spring part 11 is 12 mm and the height is 6 mm, the thickness thereof is about 0.2 mm and the width of the longitudinal slit 15 is When the thickness of the substrate 12 is about 2 mm and the thickness of the substrate 12 is about 2 mm, the desired result can be obtained. In addition, almost the same good results were obtained when other crystalline thermoplastic elastomers having similar hardness such as polyurethane elastomer and polyamide elastomer were used as the material.

Further, in the spring portion 11 of this embodiment, the lower half portion 11a has a cylindrical shape and the upper half portion 11b has a truncated cone shape, and an upper portion of the lower half portion 11a spreads by a pressing operation, and the upper half portion 11b is cut in the middle. The shape is convex downward. This change in shape occurs relatively rapidly, and is the same when returning to the original shape, so the operation is accompanied by a snap action with a crispness, and a push button switch with a good operation feeling can be obtained. The snap action is based on the overall shape and thickness of the spring portion 11 and the vertical slit 15
The strength and weakness can be adjusted depending on the width and the number of the springs. Further, for example, if the entire shape is a smooth curved surface without bending in the middle, a spring member without snap action can be obtained.

<Effect of the Invention> As is apparent from the above-described embodiments, the present invention has a thin-walled spring portion having a dome shape or a similar shape,
A substrate for mounting, which is thicker than the spring portion for supporting the spring portion, is formed of an integrally molded product of a polymeric resin material having elasticity, and the spring portion is provided with a plurality of vertical slits. is there. Therefore, it goes without saying that a metal spring is not necessary, but since the mounting substrate is hard and difficult to deform, the fixing member and the pressing member that are required in the case of the conventional rubber spring are also unnecessary,
It will be easy to reduce the total cost of keyboards by greatly reducing the number of parts and the number of assembly steps. Also, while ensuring the rigidity of the substrate, the longitudinal slits can give sufficient flexibility and spring action to the spring portion, so that a spring member with good operability can be obtained and internal stress generated in the spring portion during operation can be obtained. The smaller size also improves durability. Further, since there are few restrictions on the shape and overall size of the spring portion, it is easy to obtain a relatively large stroke, and it is possible to obtain a spring member having a wide range of applications and suitable for various devices.

Further, when a thermoplastic elastomer is used as the polymer resin material, good moldability and durability are obtained, and particularly when a thermoplastic elastomer having a Shore hardness of 40D to 55D is used, the rigidity of the substrate and the spring are increased. It becomes easy to obtain a spring member having both flexibility of the parts.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention, and FIG. 1 (a) and FIG.
(b) is a sectional view showing the structure and operation, FIG. 2 is a plan view, and FIG.
The figure is a perspective view. 1 ... Spring member, 2 ... Push button, 11 ... Spring part, 12 ... Mounting board, 15 ... Vertical slit, 16 ... Spring piece.

Claims (3)

[Scope of utility model registration request] 1. A thin-walled spring portion having a dome shape or a similar shape and pressed from the outside by a separate push button, and a thick and rigid mounting substrate for supporting the spring portion, A spring member for a push button switch, which is composed of an integrally molded product of a polymeric resin material having elasticity and has a plurality of vertical slits in the spring portion. 2. A spring member for a push button switch according to claim 1, wherein a thermoplastic elastomer is used as the elastic polymer resin material. 3. The spring member for a push button switch according to claim 2, wherein a thermoplastic elastomer having a Shore hardness of 40D to 55D is used.