JPH0650921Y2 - Switch mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a switch mechanism used for setting adjustment of a side mirror for an automobile, a keyboard switch or the like.

[Prior Art] Conventionally, as shown in FIG. 6, a switch mechanism has a key top 20 arranged in an opening 11 formed in an equipment panel 10.
And a tactile switch 40 arranged on the printed circuit board 30 inside the device panel 10.

Further, the key top 20 is formed with a plurality of protrusions 22 extending from one surface side facing the tactile switch 40 to the switch portion of the tactile switch 40. Further, a central protrusion 21 is formed on the central portion of the key top 20, that is, on one surface side facing the printed circuit board 30. The central protrusion 21 is provided with a coil-shaped return spring 50. The return spring 50 is assembled between the key top 20 and the printed circuit board 30.

Now, in order to operate the switch, when the key top 20 is pressed from the outside of the device panel 10, the tactile switch 40 operates. However, when the central portion of the key top 20 is pressed, the central projection 21 is formed to be longer than the projection 22, so that the tip of the central projection 21 hits the printed circuit board 30 and the stroke of the key top 20 is restricted. It
As a result, the tactile switch 40 switches do not operate.

Therefore, each of the tactile switches 40 operates when one surface portion of the key top 20 above the protrusion 22 is pressed downward.

In this way, by pressing the key top 20, the contact of the tactile switch 40 is switched. Further, when the pressing of the key top 20 is released, at the same time, the reaction force of the return spring 50 returns the key top 20 to the original position.

[Problems to be solved by the invention] However, a tactile switch 40 for switching contacts is mounted on the printed circuit board 30 and a return spring is provided between them.
Since 50 are arranged, the key top 20 and the printed circuit board 3
0, that is, the distance from the device panel 10 becomes large.
As a result, the thickness of the switch mechanism itself increases, making it difficult to obtain a thin switch mechanism.

Further, since each tactile switch 40 and the return spring 50 are formed of individual parts, the structure is complicated and the number of assembling steps is increased.

Therefore, a technical problem of the present invention is to provide a switch mechanism which has a simple structure and can be made thin.

[Means for Solving the Problems] According to the present invention, in a switch mechanism that operates in response to a pressing operation of a key top that is movable in a direction intersecting with a board, a plurality of contacts arranged on the board. A membrane switch having a portion, and a push plate arranged between the membrane switch and the key top,
The push plate is located between the dome and the plurality of domes that face the plurality of contact parts in a one-to-one manner and are operated by the key top to drive the contact parts. A switch mechanism having a return spring for applying a return force to the top is obtained.

[Operation] In the present invention, a plurality of movable domes are arranged at positions corresponding to the contacts of the membrane switch, and a return spring having a slit integrally provided at the center between the movable domes is arranged on the membrane switch. Then, the key top is operated and pressed by the protrusion protruding on the back surface of the key top to bend the movable dome and the return spring, thereby switching the contacts of the membrane switch.

[Embodiment] An embodiment of the present invention will be described below with reference to the accompanying drawings.

1 to 4 show a switch mechanism according to an embodiment of the present invention. In this embodiment, components similar to those shown in FIG. 6 are designated by the same reference numerals and their description is omitted.

The switch mechanism has a key top 20 arranged in the opening 11 of the device panel 10 and a membrane switch 40 arranged on the printed circuit board 30. A push plate 60 is arranged in the space formed between the key top 20 and the membrane switch 40.

The key top 20 is made of a square plate. A flange 21 extending outward is formed at the peripheral edge of the key top 20. This flange 21 is an opening of the instrument panel 10.
The key top 20 is prevented from coming off by abutting on the abutting portion 25 formed on the inner circumference of 11. On the back surface of the key top 20, that is, the one surface side facing the membrane switch 70,
A plurality of protrusions 22 (in this embodiment, formed at four locations corresponding to each edge of the square) and a central protrusion 23 that also serves as a stopper are formed.

A wiring pattern (not shown) is formed on one surface of the printed circuit board 30. The membrane switch 70 is electrically connected to the wiring patterns and has contacts 71 for switching the circuits of these wiring patterns. In this membrane switch 70, an electrically insulating spacer 70c is arranged between two electrically insulating sheets 70a, leaving a through hole 70b. Each sheet 71a inside the through hole 70b is provided with each contact 71 so as to face each other.

The push plate 60 is made by punching a phosphor bronze plate for a spring using a press machine. On the push plate 60, a plurality of movable domes 61 formed at positions facing the plurality of contacts 71 are formed. Also,
One return spring 62 is formed on the push plate 60. The return spring 62 is located at the center surrounded by each movable dome 61. As shown in FIG. 4, the return spring 62 has a plurality of arcuate slits 63 projecting in a cylindrical shape and radially extending from the central portion of the ceiling portion 66 thereof. Also, as shown in FIG.
The 63 may be formed concentrically. These slits 63
Plays a role of giving return elasticity to the return spring 62.

The movable dome 61 is formed in a dome shape. These movable domes 61 are formed with four slits 64 long in the circumferential direction with respect to the center in order to have elasticity. In addition, the movable dome 61 has contacts of the central membrane switch 70.
A protrusion 65 is formed so as to protrude in the direction of pressing 71.

Next, the operation of this switch mechanism will be described.

When the center of the key top 20 is pressed, the tip of the central protrusion 23 of the key top 20 hits the printed circuit board 30 via the return spring 62, and the stroke of the key top 20 is limited. At this time, since the contact 71 is not pressed, the circuit is not switched.

If you press a part of the area around the keytop 20,
Movable dome 61 that corresponds to the position where the tip of is pressed as a fulcrum
Bends and switches its contact point 71. At this time, the other contacts 71 do not operate.

[Advantage of the Invention] According to the present invention, the movable dome for switching the contacts of the membrane switch and the return spring are integrally molded with a metal plate so as to have the above-described configuration, and the movable dome and the return spring are combined with the key top and the printed circuit board. Since it is placed in between, it is thin and easy to configure.
Moreover, it is possible to obtain an inexpensive switch mechanism with a small number of assembling steps.

[Brief description of drawings]

1 is a sectional view showing a switch mechanism according to an embodiment of the present invention, FIG. 2 is a perspective view of the key top of FIG. 1 seen from the back side, and FIG. 3 is a top view of the push plate of FIG. FIG. 4 is an enlarged view of the return spring, FIG. 4A is a top view, FIG. 4B is a cross-sectional view, and FIG. 5 is an enlarged view showing another embodiment of the return spring. (A) is a top view, (B) is a sectional view, and FIG. 6 is a sectional view showing a conventional switch mechanism. 10 …… Device panel, 11 …… Opening, 20 …… Key top, 22
…… Protrusions, 23 …… Center protrusion, 30 …… Printed circuit board, 60…
… Push plate, 61 …… Movable dome, 62 …… Return spring, 63 …… Slit, 64 …… Slit.

Claims (1)

[Scope of utility model registration request] 1. A switch mechanism which operates in response to a pressing operation of a key top movable in a direction intersecting with a board,
It includes a membrane switch having a plurality of contact portions arranged on the substrate, and a push plate arranged between the membrane switch and the key top, and the push plate has a pair of contact portions on the plurality of contact portions. A plurality of domes that face each other and are operated by the key top to drive the contact portion; and a return spring that is located between the plurality of domes and provides a return force to the key top. A switch mechanism characterized by being present.