JPS6134666Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a push-button switch structure used in push-button telephones and the like.

Usually, a push-button dial switch such as a telephone has a contact pattern formed on a printed board, and an elastic sheet having a total of 12 elastically deformable bowl-shaped contacts arranged in 4 rows and 3 columns is provided on this printed board. The elastic sheet and printed board are covered by a cover equipped with a push button at a position corresponding to each bowl-shaped contact portion, and this cover has a guide pin that fits into a positioning hole provided in the elastic sheet and printed board. It is. When such a pushbutton switch is used in a wall-mounted telephone, for example, if the telephone accidentally falls from the wall-mounted state, the impact will cause the guide pin to break from its base, causing the elastic sheet to shift and cause the bowl-shaped contact portion and the printed board to fall. There was a risk that the switch function would be impaired because the contact pattern did not correspond accurately.

The present invention was devised in view of the above points, and is equipped with a guide pin that does not easily break at its base even when subjected to impact such as a fall, and an elastic sheet that does not easily shift its position even when subjected to impact. The purpose is to provide a button switch structure. Therefore, in the push button switch structure according to the present invention, the entire outer peripheral edge of the elastic sheet and printed board engages with the side wall of the cover that covers them, and the position is fixed with respect to this cover, and the guide pin of this cover is compressed. It has a radial tip and an enlarged root.

FIG. 1 is a sectional view of an embodiment of a push button switch according to the present invention. An elastic sheet 2 made of insulating rubber or the like is provided on a printed board 1 and has a total of 12 (only 3 shown) elastically deformable bowl-shaped contact portions 2a arranged in 4 rows and 3 columns. A movable contact 3 made of conductive rubber is provided inside each bowl-shaped contact portion 2a. The movable contact 3 comes into contact with the printed board 1 by pressing the push button 4 arranged on the upper part of each bowl-shaped contact part 2a, and the contact pattern (not shown) is made conductive. A common actuation shaft 6 is provided, for example, between the first and second pushbutton rows and between the third and fourth pushbutton rows. An actuation lever 5 is provided which engages each pushbutton 4 and acts on this common actuation part 6. Therefore, no matter which push button 4 is pressed, the common contact 7 is activated via the common actuation shaft 6. The elastic sheet 2 and printed board 1 are covered with a cover 8 made of synthetic resin or the like. This cover 8 is placed in a suitable position, for example 4
It has a support part 8a at two places and a guide pin 9 at its tip.
is formed. The guide pins 9 fit into positioning holes provided in the printed board 1 and the elastic sheet 2. The positioning holes in the printed board 1 are smaller than the positioning holes in the elastic sheet 2. Guide pin 9
is composed of a diameter-reduced tip portion 9a that fits into a positioning hole in the printed board 1 and an enlarged root portion 9b that fits into a positioning hole in the elastic sheet 2. The entire outer peripheral edges of the elastic sheet 2 and the printed board 1 are engaged with the inner surface of the side wall 8b of the cover 8, and their positions are fixed.

In the push button switch structure as described above, the root part of the guide pin 9 of the cover 8 has a large diameter, so it will not easily break from the root part even if there is an impact, and in the unlikely event that the diameter-reduced tip part 9a breaks. Even if the printed circuit board 1 is fixedly held by the side wall 8b of the cover 8, it will not shift, and the elastic sheet 2 will not shift since it is also fixedly held by the side wall 8b of the cover 8 and the enlarged root portion 9b of the guide pin 9. Therefore, the switch function will not be impaired due to misalignment of the contact pattern positions of the movable contact 3 and the printed board 1. In addition, a common contact shaft 6 provided on the elastic sheet 2
Since the common contact 7 will not be displaced, the common contact 7 will operate reliably even after the telephone is dropped. Also,
When guide pins 9 are provided on two of the four support parts 8a of the cover 8 and the remaining two are used to fix the printed board 1 from below with screws, etc., a step is formed on the guide pins 9. Therefore, the elastic sheet 2 will not be excessively compressed and deteriorated due to over-tightening of the screws. Note that the shape of the guide pin 9 may be a truncated cone shape as shown in FIG.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a push-button switch according to the present invention, and FIG. 2 is a partial cross-sectional view of another embodiment of the push-button switch according to the present invention. 1... Printed board, 2... Elastic sheet, 4...
Push button, 8... Cover, 9... Guide pin, 2
a... Bowl-shaped contact portion, 8b... Side wall.

Claims (1)

[Scope of utility model registration request] An elastic sheet having a plurality of elastically deformable bowl-shaped contact portions is provided on a printed board, and the elastic sheet and the printed board are covered by a cover provided with a push button at a position corresponding to each bowl-shaped contact portion, and the cover is In the push button switch having a guide pin that fits into a positioning hole provided in the elastic sheet and the printed board, the end edges of the elastic sheet and the printed board engage with the side wall of the cover and are positioned relative to the cover. is fixed, and the guide pin of the cover has a reduced diameter tip and an enlarged root.