JPS62117228A - Keyboard switch - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a keyboard switch, and more particularly to a keyboard switch using a metal Of helper spring having a reversal displacement characteristic.

(Prior technology) In order to obtain a sense of movement by pressing down on the key top with finger pressure and reliable contact, a movable gold mH spring with reverse displacement characteristics is used for the keyboard switch, so that a snap action can be obtained. are often used. Conventionally, this type of keyboard switch has a dome shape, a modified dome shape, and a gold spring with reversal displacement characteristics placed on the switch board as a movable contact spring, so that multiple points around the spring can also serve as conductors. It serves as a fulcrum and allows contact to be made between the contact provided at the center of the spring and the fixed contact provided at the center of the board. In addition, another spring is inserted between the key top and the center upper surface of the movable contact spring to provide an appropriate amount of depressing displacement, and when the depressing pressure of the key dog reaches a certain value, the contacts are brought into contact in a snap manner. It has become.

(Problem to be Solved by the Invention) However, in the above configuration, when the pressing pressure of the key top reaches the reverse displacement pressure of the spring having reverse displacement characteristics, the spring stress decreases and the amount of displacement rapidly increases. , the movable contacts provided on the base plate collide with the fixed contacts on the board and stop. Therefore, depending on the speed of the collision, there is a problem in that the wear of the contact points becomes considerably large.

SUMMARY OF THE INVENTION An object of the present invention is to provide a keyboard switch that can alleviate the above-mentioned drawbacks and extend the life of the contacts.

(Means for Solving the Problems) The present invention provides, in addition to the original spring with reverse displacement characteristics, between the fulcrum of a metal movable spring having reverse displacement characteristics and a contact point provided at the center of this spring. It is constructed by providing an auxiliary spring with a linear characteristic that operates in series with this spring. In this configuration, as shown in the strain stress characteristic diagram of the spring in FIG. The amount of displacement from the reversal point of a spring with reverse displacement characteristics to the fixed contact becomes small, and when the movable contact collides with the fixed contact, the energy is also small, causing the movable contact to land soft on the fixed contact. .

Moreover, the contact pressure remains unchanged from the conventional one.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a perspective view of one embodiment of a movable spring used in the present invention.
2 is configured as a moving point.

This central portion 12 is connected to a central spring 14 that connects the centers of both side edge portions 11 via yokes 13 provided symmetrically, and the yoke 13 constitutes a sub-spring with the central spring 14 as a fulcrum. . On the other hand, a pair of side springs 1 connect the corresponding ends of the center spring 14 and both side edges 11.
5 constitutes a spring exhibiting reverse displacement characteristics. Furthermore, a movable contact 1G is provided at the center of the back surface of the center portion 12.

FIG. 2 is a perspective view of the keyboard switch using the movable spring shown in FIG. 1, and is constructed in the same way as the conventional keyboard switch. In the figure, the nousing 21 which is a switch board has a fulcrum holder 22 which also serves as a conductor on both sides of the inner surface and a fixed contact 23 in the center, and the movable spring 100 of FIG. 1 is straddled over both fulcrum holders 22. There is. Further, a coil spring 25 is provided at the upper center of the movable spring 100 via a spring guard 24, and a key top 26 is provided above the coil spring 25.

Figure 3 is a visual diagram of a conventional movable spring without a secondary spring.
In the figures, the same reference numerals as in FIG. 1 indicate the same things.

FIG. 4 is a strain stress curve diagram of the movable spring of FIGS. 1 and 2, in which the vertical axis shows the pressing pressure F applied to the center of the movable spring, and the horizontal axis shows the displacement of the movable contact.

In the figure, the solid line is for the movable spring in Figure 1, and the dotted line is for the third movable spring.
The case of the movable spring shown in the figure is shown, and the movable spring of FIG. 1 is displaced by the displacement of the sub spring 13 of the movable spring of FIG. 1 with respect to the movable spring of FIG. The amount of displacement has increased. However, when the contact pressure between the movable contact and the fixed contact is the same f, the displacement point of the movable spring in FIG. 1 is d.

The displacement d, -d corresponding to the displacement d from to the fixed contact.

is smaller than the displacement d4-d, which corresponds to the displacement d4 from the displacement point of the movable arm in Fig. 2 to the displacement d4 to the fixed contact, and by that much the movable contact in Fig. 1 becomes the fixed contact. This shows that contact wear is reduced by reducing impact energy.

5 and 6 each show another embodiment of the movable spring used in the present invention, in which the same reference numerals as those in FIG. 1 are designated by the same reference numerals. Although the yoke 13 provided on the movable spring in FIG. 5 is attached in a direction 90° different from the yoke 13 in FIG. In addition, in Fig. 6, cantilever springs 18 are attached to the four corners of the movable spring, and the tips of the cantilever springs 18 act as fulcrums by straddling the fulcrum holder provided on the switch board, but the edges on both sides of the movable spring 17 is a virtual fulcrum of a spring exhibiting reverse displacement characteristics, and in this case as well, the spring having reverse displacement characteristics and the cantilever spring 18, which is an auxiliary spring, form a series spring configuration, which is the same as the movable spring in FIG. It has the effect of

(Effects of the Invention) As explained in detail above, the keyboard switch of the present invention has the same contact pressure as the conventional one, but reduces the collision energy when the contacts make contact, thereby extending the life of the contacts and, by extension, the life of the keyboard switch. There is an effect.

[Brief explanation of drawings]

Figure 1 is a perspective view of an embodiment of a movable spring used in the present invention, Figure 2 is a schematic diagram of a keyboard switch using a movable spring with reverse displacement characteristics, and Figure 3 is a conventional one with reverse displacement characteristics. FIG. 4 is a perspective view of a typical movable spring, FIG. 4 is a strain stress characteristic diagram of the movable spring, and FIGS. 5 and 6 are perspective views of other embodiments of the movable spring used in the present invention. 11.19...Fully point, 13...Yoke, 16...--Movable contact, 18...Cantilever spring, 22...Fulcrum holder , 23...Fixed contact. Kaya no 1 mo [Σ

Claims (1)

[Claims] In a keyboard switch that uses a metal movable spring that has a movable contact in the center and has reverse displacement characteristics, a secondary spring that operates in series with the spring that has reverse displacement characteristics between the fulcrum of the movable spring and the central movable contact. A keyboard switch characterized by having.