JPH0992073A - Fitting structure for rubber switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve assembly workability by making the tip side of the key top abut on a guiding rib to be guided toward a through hole to be inserted into a tubular part, and surely protrude the tip side outside a case body from the through hole. SOLUTION: In overlapping a rubber seat 2 on the inner side bottom surface of a case body 3, when the key top 21 of the rubber seat 2 is inserted into the tubular part 32 of the body 3, the tip side of the key top 21 abuts on the tilted surface 51 of a guiding rib 5, protruded from the inner peripheral surface of the tubular part 32, to be guided by the tilted, surface 51 to be led into a through hole 31. Consequently, the rubber seat 2 eliminates causing failure as usual, to surely protrude the tip side of the key top 21 outward from the through hole 31 of the body 3, and to make a seat surface abut on the tip surface of the tubular part 32, thereby overlapped to the inner bottom surface of the body 3. Then, respective fixed contacts 41a and 41b are overlapped, while facing the movable contact 25 of the seat 2, by a printed board 4; and then are fitted to the body 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a mounting structure of a rubber switch used in an operating section of information processing equipment or the like.

[0002]

2. Description of the Related Art Conventionally, a rubber switch mounting structure shown in FIG. 3 has been known. FIG. 3A is an exploded perspective view and FIG. 3B is a sectional view. The rubber switch mounting structure 1 includes a rubber sheet 2, a rubber sheet 2, a case main body 3 superposed on the rubber sheet 2, and a case main body 3 disposed on the lower surface side of the rubber sheet 2.
It is composed of a printed circuit board 4 for sandwiching. The rubber sheet 2 is formed of a soft rubber material having an insulating property in a plate shape, and a plurality of circular key tops 21 are projectingly provided on the upper surface thereof. As shown in FIG. 3B, the key top 21 includes a body portion 22 that bulges from the plate surface of the rubber sheet 2, and a body portion 2
It has integrally with the pressing part 23 following 2. A recess 24 is formed on the lower surface of the rubber sheet 2 at a position corresponding to each of the key tops 21, and a movable contact 25 made of conductive rubber is attached to the bottom of the recess 24. The peripheral wall of the body portion 22 is formed in a thin shape by the recess 24, and when the switch is operated, the pressing portion 23 is moved downward by bending the peripheral wall of the body portion 22.

Next, the case body 3 is made of, for example, ABS resin or the like in a box shape, and the bottom surface thereof is matched with the arrangement pitch of the key tops 21 of the rubber sheet 2.
A plurality of through holes 3 through which the pressing portion 23 of the key top 21 is inserted
1 is pierced. Further, from the vicinity of the peripheral edge of each through hole 31, a cylindrical portion 32 surrounding the periphery of the key top 21 inserted into the through hole 31 is provided so as to be concentric with the through hole 31. On the other hand, on the surface of the printed circuit board 4, fixed contacts 41a, 41 are provided corresponding to the movable contacts 25 of the respective key tops 21.
b is provided. These fixed contacts 41a and 41b form a switch together with the movable contact 25, and are formed by a pair of conductive foils printed on the printed circuit board 4.

Next, when assembling the above-mentioned rubber switch mounting structure, in the rubber sheet 2, each key top 21 is inserted into the corresponding cylindrical portion 32 of the case body 3, and the tip end side of the key top is inserted from the through hole 31 to the case. The sheet surface is brought into contact with the tip end surface of the tubular portion 32 while being projected to the outside of the main body 3, and is superposed on the inner bottom surface of the case main body 3. Next, the printed circuit board 4 is attached to the case main body 3 after the fixed contacts 41a and 41b are superposed with the corresponding movable contacts 25 on the rubber sheet 2 side facing each other. In the rubber switch mounting structure assembled as described above, the movable contact 25
The elastic force of the rubber sheet 2 causes the fixed contacts 41a,
It is separated from 41b. For this reason, when the switch is operated, the movable contact 25 is pushed down while the key top 21 is pushed down while elastically deforming the body portion 22, so that the movable contact 25 is fixed.
The switch operation is performed by contacting 41b and short-circuiting between the fixed contacts 41a and 41b.

[0005]

By the way, in the above-mentioned rubber switch mounting structure, when the rubber sheet 2 is superposed on the case body 3, the tip of the key top 21 inserted into the tubular portion 32 of the case body 3 is inserted. The portion was easily caught on the peripheral portion of the through hole 31 as shown in FIG. For this reason, the pressing portion 23 of the key top 21 does not completely protrude from the through hole 31, and a problem that the pressing portion 23 is incorporated in the case body 3 in a tilted state occurs, resulting in poor assembly workability and impaired reliability. became. The present invention has been made to solve the above-mentioned drawbacks, and when the rubber sheet is incorporated into the case body, by reliably inserting the key top into the through hole, the assembling workability is improved, and Provide a rubber switch mounting structure with increased reliability.

[0006]

The present invention has a rubber sheet having a plurality of key tops provided with movable contacts therein, and a plurality of through holes into which the key tops are inserted.
A cylindrical portion surrounding the key top is integrally projected from the vicinity of the periphery of the through hole, and a case body arranged on the rubber sheet and a fixed contact corresponding to a movable contact of the key top are arranged, In a rubber switch mounting structure including a printed circuit board laminated on the lower surface side of the rubber sheet, a guide rib for guiding the key top toward the through hole is projected on the inner peripheral surface of the tubular portion. It was set up.

In the rubber switch mounting structure configured as described above, when the rubber sheet is assembled in the case body, the key top inserted into the tubular portion is brought into contact with the guide rib at its tip end side. While being guided, it is introduced into the through hole. Therefore, the key top is surely projected to the outside of the case main body through the through hole, so that the assembling workability is improved, and the rubber switch mounting structure having improved reliability is obtained.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 is a sectional view showing a rubber switch mounting structure, FIG. 2 (a) is a partial perspective view of a case body according to the present invention, and FIG. 2 (b) is a sectional view of FIG. 1 (a). For the same shape and the same purpose as the conventional example, the same reference numerals are used and the detailed description thereof is omitted.

The difference between the present invention and the conventional example is that, as shown in FIG. 2, a plurality of guide ribs 5 are projected on the inner peripheral surface of the cylindrical portion 32 of the case body 3 at regular intervals in the circumferential direction. I set it up. Each of the guide ribs 5 extends from the open end of the tubular portion 32 toward the through hole 31, and is continuous with the bottom surface of the case body 3 around the through hole 31. Further, at the upper end of the guide rib 5, the slope 5 is formed so that the protruding height of the guide rib 5 gradually increases from the opening side of the tubular portion 32 toward the through hole 31.
1 is formed, whereby the upper end surface of the guide rib 5 continuous with the bottom surface of the case body 3 is aligned with the inner peripheral surface of the through hole 31.

Next, to assemble the rubber switch mounting structure as shown in FIG. 1, the rubber sheet 2 is first superposed on the inner bottom surface of the case body 3. At that time, the key top 21 of the rubber sheet 2 is placed in the tubular portion 32 of the case body 3.
When the key is inserted, the tip end side of the key top 21 comes into contact with the slope 51 of the guide rib 5 protruding from the inner peripheral surface of the tubular portion 32, and is guided into the through hole 31 while being guided by the slope 51.
Therefore, the rubber sheet 2 does not cause the assembly failure shown in the conventional example, the tip end side of the key top 21 is surely projected outward from the through hole 31 of the case body 3, and the seat surface is a cylindrical portion. It is brought into contact with the front end surface of 32 to be superposed on the inner bottom surface of the case body 3. Next, the printed circuit board 4 is attached to the case main body 3 after being superposed with the fixed contacts 41a and 41b facing the corresponding movable contacts 25 of the rubber sheet 2. As a result, the case body 3
The rubber switch mounting structure is assembled with the rubber sheet 2 sandwiched between the printed circuit board 4 and the printed circuit board 4.

[0011]

As described above, in the rubber switch mounting structure of the present invention, the guide rib for guiding the key top toward the through hole is integrally formed on the inner peripheral surface of the cylindrical portion provided in the case body. It is the one protruding from. As a result, when the rubber sheets are superposed on the case body, the key top is inserted into the cylindrical portion while being guided toward the through hole by abutting the leading end against the guide rib, so that the leading end of the key top is inserted into the through hole. It is possible to reliably project from the case to the outside of the case body. For this reason, it is possible to provide a rubber switch mounting structure with improved assembly workability and reliability.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a rubber switch mounting structure of the present invention.

2A is a perspective view showing a part of a case body according to the present invention, and FIG. 2B is a sectional view of FIG. 2A.

3A is an exploded perspective view showing a rubber switch mounting structure in a conventional example, and FIG. 3B is a sectional view showing the rubber switch mounting structure in FIG. 3A.

FIG. 4A is a perspective view showing a part of a conventional case body, and FIG. 4B is a sectional view of FIG.

FIG. 5 is a cross-sectional view showing a defect example in a conventional rubber switch mounting structure.

[Explanation of symbols]

 1 Rubber switch mounting structure 2 Rubber sheet 21 Key top 25 Moving contact 3 Case body 31 Through hole 32 Cylindrical part 4 Printed circuit boards 41a and 41b Fixed contact 5 Guide rib 51 Slope

Claims (2)

[Claims] 1. A rubber sheet in which a plurality of key tops having movable contacts are arranged, a plurality of through holes into which the key tops are inserted, and the key tops are provided near the periphery of the through holes. A print in which an enclosing tubular portion is integrally projected, a case main body disposed on the rubber sheet and a fixed contact corresponding to the movable contact of the key top are disposed, and the lower surface side of the rubber sheet is superposed. In a rubber switch mounting structure including a board, a rubber switch mounting structure characterized in that a guide rib for guiding the key top toward the through hole is provided on an inner peripheral surface of the tubular portion. Construction. 2. The rubber switch mounting structure according to claim 1, wherein the guide rib is formed with an inclined surface for guiding the key top to the through hole.