JPS5929932B2 - Method for manufacturing a movable contact member for a push button switch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a push button switch using rubber contacts, and particularly to a method of manufacturing a movable contact member that has low contact resistance and is suitable for mass production.

Figure 1 shows a conventional method for manufacturing rubber contacts, in which 1 is a contact piece punched out of a conductive rubber sheet, which is placed in a mold 2a.
The movable contact body 4 for a push-button switch as shown in FIG. 2 is manufactured by inserting the contact body 4 into an insulating rubber 3 and molding it integrally into an insulating rubber 3 using molds 2b and 2c, and then punching it. Inserting the contact piece 1 into the mold 2 is time-consuming, and the integration process takes a considerable amount of time (about 10 minutes).

Further, since the conductive rubber sheet is highly elastic, it is not suitable for automatic insert molding in the sheet state, so individual contact pieces 1 are punched out in advance as described above.
This has to be inserted one by one into the mold 2a, which has the disadvantage that automation is difficult and it is not suitable for mass production 1.

The present invention aims to eliminate the drawback of slanting, and embodiments thereof will be described in detail below with reference to the drawings.

FIG. 3a shows a conductive fiber sheet 10 formed by densely weaving carbon fibers into a thin cloth.

First, let's look at Figure 3. In the first step shown in C, for example, a so-called conductive rubber sheet 11 in which fine carbon powder is mixed and dispersed in silicone rubber is stacked and pressed onto the conductive fiber sheet 10, so that the cross section becomes as shown in C in the figure. One contact plate 12 is formed into a hoop shape, and then in the second step shown in FIG.
... to form.

Next, in a third step, the strip 13 is set in a mold (not shown).

Umbrella-shaped cavities corresponding to cover members to be described later are provided in the mold at regular intervals.

When an insulating material such as silicone rubber is injected into the cavity and integrally molded, umbrella-shaped cover members 14 are bonded to the strip strips 13.

The time required for molding in the third step is only about 30 seconds.

Figure 4 a and b are taken out from the mold, a is a bottom view, b is a top view, Figure 5 is an AA sectional view of Figure 4, and Figure 6 is a BB sectional view. In the fourth and final step, the contact portion 1 is formed by pressing and cutting from the state shown in FIG.
5, individual movable contact bodies 16 (FIG. 7) are formed.

FIG. 8 shows a push button switch using a movable contact body 16 according to the present invention, in which fixed contacts 17 and 17 are formed on an insulating substrate opposite to the contact portion 15.

As shown above, in the present invention, a conductive fiber sheet and a conductive rubber sheet are integrated into a continuous hoop shape at the stage of the contact plate 12, and the contact plate 12 has almost no elasticity and has a moderate degree of elasticity. It takes advantage of its strength, and allows a large number of movable contact bodies to be molded at once by automatic insert molding.

Therefore, by applying the present invention, the manufacturing of rubber contacts can be easily automated, mass-producible, and costs can be reduced, and remarkable effects can be achieved, such as being able to provide an inexpensive push button switch.

[Brief explanation of the drawing]

Fig. 1 shows a conventional method for molding a movable contact body, Fig. 2 shows a conventional movable contact body, Fig. 3 and the following relate to the present invention, and Fig. 3 a = d.
4A is a manufacturing process diagram of the contact strip, FIG. 4A is a bottom view showing the state of the movable contact body after molding;
6 is a sectional view of FIG. 4, FIG. 7 is a front view of the movable contact body, and FIG. 8 is a longitudinal sectional view of the push button switch. DESCRIPTION OF SYMBOLS 10... Conductive fiber sheet, 11... Conductive rubber sheet, 12... Contact plate, 13... Strip strip, 14...
- Cover member, 15... Contact portion, 16... Movable contact member.

Claims (1)

[Claims] 1 A step of bonding a conductive fiber sheet and a conductive rubber sheet to form a contact plate, a step of cutting the contact plate into strips to form strips, and a step of attaching insulating rubber to the strips. forming a cover member by injection molding;
A method for manufacturing a movable contact member for a push button switch, characterized in that the step of forming the movable contact member by pressing the molded body forms a contact portion on the lower surface of an umbrella-shaped cover member.