JPS5926991Y2 - Conductive elastomer type key switch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a conductive elastomer key switch using a dome-shaped elastomer spring having conductive elastomer contacts.

For convenience of explanation, an example will be exemplified below in which rubber is used as the elastomer.

An example of the structure of a conventional conductive rubber key switch is shown in FIG.

In Fig. 1, 1 is a dome-shaped rubber spring made of silicone rubber (hereinafter simply referred to as a rubber spring), and a spring portion 2
, a base portion 3, a pressing portion 4, and a contact portion 5, the contact portion 5
is provided with a conductive rubber contact 6, the base 3 of which is located on a base 7.

8 is a key lever, 9 is a key top, and when the key top 9 is pressed down, the conductive rubber contact 6 short-circuits between a pair of fixed contacts 10 provided on the base 7.

Also, the large diameter portion 8 at the bottom of the rubber spring 1 and the key lever 8
a is housed in the housing 11.

Further, the base 7 has a structure that can be attached to and detached from the housing 11.

This action is such that when the key top 9 is pressed down, the rubber spring 1 deforms, and the conductive rubber contacts 6 short-circuit between the fixed contacts 10.

If this pressing is repeated, the spring portion 2 will become fatigued and eventually break.

In order to extend the service life, it is necessary to make the spring part resistant to fatigue, and for this purpose, it is important to reduce the stress in the spring part 2.

In order to reduce the stress, it is effective to reduce the thickness of the spring portion 2, reduce the amount of deformation, etc.

When the stroke of the key switch is constant, the spring part 2
The larger the diameter is, the smaller the amount of deformation in each part, which is advantageous for extending the life.

The part where the diameter of the spring part 2 is largest is the lowest part, that is, the base part 3, and it is important to make the base part 3 as large as possible.

However, the space for arranging the key switch is limited, and the size of the key switch itself is determined by itself, which poses a problem in the durability of the key switch.

This invention was made in order to eliminate the above-mentioned drawbacks, and was designed to maximize the diameter of the spring portion within the limited dimensions of the housing, thereby improving durability.

This invention will be explained in detail below with reference to the drawings.

FIG. 2 shows an embodiment of this invention, and is a bottom view with the base 7 removed.

In this figure, reference numeral 12 denotes an arc-shaped depression formed on each wall surface of the housing 11, and the base 3 of the rubber spring 1 is inserted into the arc-shaped depression 12.

Therefore, the spring portion 2 can be made as large as possible within the limited dimensions of the housing 11.

Reference numeral 13 denotes a projection for locking the base 7 to the housing 11, and is provided at an end of the housing 11, that is, at a position away from the spring portion 2 of the rubber spring 1 inscribed in the housing 11.

FIG. 3 is a side view of the key switch shown in FIG. 2, with the base 7 locked to the housing 11.

That is, a cantilever-shaped locking spring 14 is attached to the base 7.
is attached, and the tip 15 of the locking spring 14 is L.
When the base 7 is fitted into the housing 11 from below, it slides on the slope of the protrusion 13, and when the base 7 comes into contact with the lower end of the housing 11, the tip 15 comes off the slope of the protrusion 13. As shown in the figure, the base 7 is locked to the housing 11 by the tip 15 of the L-shaped portion being hooked on the protrusion 13.

Four locking springs 14 are provided corresponding to the four protrusions 13.

Since this locking mechanism does not use the central part of the wall of the housing 11, it does not interfere with increasing the diameter of the base 3 of the rubber spring 1.

In the above embodiment, the case of a conductive comb type key switch has been described, but this invention is not limited to rubber, and any material having flexibility and elasticity like rubber, that is, elastomer may be used.

Similarly, the conductive rubber contact 5 may also be a conductive elastomer contact.

As explained above, in this invention, the inner wall surface of the housing in which the base of the elastomer spring is inscribed is made into an arc-shaped recess, so that the spring portion of the elastomer spring can be made as large as possible within the limited housing dimensions. This makes it possible to improve durability and extend life.

In addition, when attaching the base to the housing, a protrusion is provided at a position that avoids the spring part of the elastomer spring inscribed in the housing, and the locking spring provided on the base is locked to this protrusion. The advantage is that the spring portion of the spring can be made larger.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing the configuration of a conventional key switch;
The figure is a bottom view with the base removed of a key switch showing an embodiment of the invention, and FIG. 3 is a side view of the key switch shown in FIG. 2 with the base locked to the housing. In the figure, 1 is a rubber spring, 2 is a spring part, 3 is a base, 6 is a conductive rubber contact, 7 is a base, 8 is a key lever, 9 is a key top, 10 is a fixed contact, 11 is a housing, 12 is a circle 13 is a protrusion, 14 is a locking spring, and 15 is a tip.

Claims (1)

[Scope of utility model registration request] The key switch is configured such that, by pressing down a dome-shaped elastomer spring housed in a housing and having a conductive elastomer contact, the conductive elastomer contact short-circuits a pair of fixed contacts provided on the base. A portion of the inner wall surface of the lower portion of the housing in which the base of the dome-shaped elastomer spring is inscribed is formed into an arc-shaped recess, and a mechanism for locking the base to the housing is located at a position other than the position where the arc-shaped recess is formed. A conductive elastomer type key switch characterized by being provided with.