JPS6311728B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a push button switch having a plurality of contacts supported by a flexible support.

The structure and operation of a conventional push button switch of this type will be explained with reference to FIGS. 1 and 2. Reference numeral 1 denotes a substrate made of a copper-clad laminate or the like, and a plurality of fixed electrodes 2 are provided on the surface thereof. Reference numeral 3 denotes a cup-shaped support made of a flexible insulator such as silicone rubber, and the support 3 is attached to the substrate 1 so as to cover the fixed electrode 2. A thick part 4 is formed on the top of this support, and a plurality of contacts 5 corresponding to the fixed electrodes 2 are attached to the lower surface of the thick part 4.

Here, as shown in FIG. 2, when the thick part 4 of the support body 3 is pushed down in the direction of the arrow directly with a finger or through a button or the like, the side surface of the support body 3 is bent and the thick part 4 is pressed down. When the contact points 5 are displaced downward on the body and the contact points 5 contact the fixed electrodes 2 on the substrate 1, the fixed electrodes 2
is in the switch ON state.

When the pressing force on the thick part 4 is released, the support 3 returns to its original cup shape due to its own recovery force.
As a result, the contacts 5 separate from the fixed electrodes 2 and turn off.

FIG. 3 is a diagram showing the pressing force-displacement characteristics of the conventional pushbutton switch mentioned above, where P is the pressing force,
δ indicates displacement. As seen in this figure, when the thick part 4 of the support body 3 is pushed down, the P-δ curve changes and moves up to the load rising point F.
f ₁ and f ₂ indicate contact points in the case of contact contact. Here, if the contact point f ₂ is after the load rising point F, the load will rise rapidly and the load difference ΔP with respect to the displacement timing difference Δδ between the contact points f ₁ and f ₂ will become large. In order to reliably contact the fixed electrode 2, it is necessary to bring each contact 5 into contact with the fixed electrode 2 at the same time at the load rising point F, or to continue the operation even after passing the load rising point F.

However, with conventional pushbutton switches in which the contact point is simply supported on the lower surface of the thick part of the support, continuation of operation after the load rise point F as described above cannot be expected due to an increase in the pressing force; It is difficult to contact multiple contacts at the same time at the rising point F due to variations in component precision and operation, so it has the disadvantage that multiple contacts cannot be brought into contact with the fixed electrode simultaneously and reliably. .

The present invention aims to solve such drawbacks, and in order to achieve this purpose, a plurality of contact seats are formed protruding from the lower surface of the thick part of the support, and a contact is attached to each of the contact seats. Accordingly, the timing of the contact point between the contact point and the fixed electrode of the substrate is set before the load rise point.

An embodiment of the present invention will be described below with reference to the drawings. In FIGS. 4 to 7, reference numeral 6 denotes a support according to the present invention, which is formed into a cup shape from a flexible insulator and is fixed. It is attached to the substrate 1 so as to cover the electrode 2. A plurality of contact seats 8 are formed protruding from the lower surface of the thick part 7 provided at the top of the support body 6, and the contacts 5 corresponding to the fixed electrodes 2 are attached to the contact seats 8, respectively. .
A hole 9 is provided in the thick part 7 to determine the deflection load of the contact seat 8, and a hole 9 is provided near the contact seat 8 to prevent the contact seat 8 from being plastically deformed due to switch operation. A boss 10 is formed.

The above-mentioned configuration includes a support 6 as shown in FIG.
When the thick part 7 of the support body 6 is pushed down in the direction of the arrow directly with a finger or via a button or the like, the side surface of the support body 6 bends and the contact point 5 is displaced together with the thick part 7, as shown in FIG. , contacts the fixed electrode 2 of the substrate 1. When the thick part 7 is further pushed down, the contact seat 8 is bent, and at the same time, the contact 5 is pressed against the fixed electrode 2 by the bending force of the contact seat 8, ensuring reliable contact between each contact 5 and the fixed electrode 2. obtained, and the switch is turned on. At this time, the boss 10 hits the substrate 1 and the resulting increase in load can be felt with the fingers, so the operation of pushing down the thick portion 7 is stopped at this point. To return the switch to the OFF state, release the pressing force on the thick part 7, and the contact 5 will be restored by the restoring force of the support 6.
is separated from the fixed electrode 2.

In the present invention, the contacts 5 are individually attached to the contact seats 8 formed on the lower surface of the thick part 7 of the support 6, and when the contacts 5 and the fixed electrode 2 come into contact, each contact seat 8 is attached independently. Since the bending load of the contact seat 8 can be determined by the size of the hole 9 provided in the thick wall portion 7, the load difference ΔP for the displacement timing difference Δδ can be freely obtained. , thereby making it possible to reliably bring the plurality of contacts 5 into contact with the fixed electrode 2 before the load rise point F.

FIGS. 8 and 9 are diagrams showing the pressing force-displacement characteristics in the above-mentioned embodiment, and as is clear from both figures, contact between the two contact points f ₁ and f ₂ can be obtained before the load rise point F. Can be done.

As explained above, in the present invention, a contact seat is formed protruding from the lower surface of a thick part provided at the top of a support body, and a contact is attached to each contact seat, thereby making a plurality of contacts per key independent. This ensures a constant load and displacement of the contacts, so even if there are operational fluctuations or component accuracy fluctuations, reliable contact between multiple contacts and fixed electrodes on the board can be achieved. It is effective and can be used for keyboards of communication terminal equipment.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a conventional example, FIG. 2 is a sectional view showing its operating state, FIG. 3 is a diagram showing the pressing force-displacement characteristics in the conventional example, and FIG. 4 is an example of an embodiment of the present invention. 5 is a sectional view showing its operating state, FIG. 6 is a plan view of the support used in the present invention, FIG. 7 is a bottom view of the same, and FIGS. 8 and 9 are views of the present invention. It is a figure showing the pressing force-displacement characteristic in the example. DESCRIPTION OF SYMBOLS 1... Substrate, 2... Fixed electrode, 5... Contact, 6... Support, 7... Thick part, 8... Contact seat, 9... Hole, 10... Boss.

Claims (1)

[Scope of Claims] 1. A push button switch comprising a flexible cup-shaped support mounted on a substrate provided with a fixed electrode, and a plurality of contacts corresponding to the fixed electrode mounted on the support, Contact seats are formed on the lower surface of the thick part provided at the top of the support body so as to protrude independently according to the number of contacts, and a hole is provided for attaching a contact to each contact seat and determining the deflection load of the contact seat. A push-button switch characterized in that the thick wall portion is provided in correspondence with each contact seat. 2. The push button switch according to claim 1, characterized in that the support body is provided with a boss for preventing plastic deformation of the contact seat.