JPH0249619Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to an improvement of a push-button switch that uses a click dome to provide a click feeling.

[Prior art]

7 to 9 show a conventional push button switch 10. FIG.

This push button switch 10 has a conductive path 1
2 and 14 are arranged one above the other with a spacer 16 in between, a click dome 18 is placed on the conductive path 12, and a key top 20 is installed above the click dome 18.

In this push button switch 10,
When the key top 20 is pressed down from the state shown in FIG. 7, the click dome 18 is deformed as shown in FIG.
a contacts the contact point 14a of the conductive path 14, and the conductive path 1
2 and 14 are measured. During this period, that is, from when the click dome 18 begins to be displaced until the contact point 12a of the conductive path 12 comes into contact with the contact point 14a of the conductive path 14, the click action of the click dome 18 is performed. When the pressing force on the key top 20 is released, the click dome 18 returns to its original shape as shown in FIG. 7 by its own restoring force, and the key top 20 is pushed up by the click dome 18. Then, the electrical connection between the conductive paths 12 and 14 is released. Note that while the click dome 18 returns to its original shape, the click dome 18 performs a click operation.

By the way, the above-mentioned push button switch 10
Due to its structure, when the key top 20 is pressed down, the conductive paths 12 and 14 are made conductive after the click operation, and when the pressing force of the key top 20 is released, the conduction between the conductive paths 12 and 14 is broken and then the click operation is performed. will be done. That is, in such a push-button switch 10, the conductive paths 12 and 14 take two states, a state in which they are electrically connected and a state in which they are electrically disconnected, during the two click operations described above.

Therefore, in the above push button switch,
Even if the operator presses the key top 20 and feels a click, this does not necessarily mean that the conductive paths 12 and 14 are electrically connected, and the switch operation is uncertain. As a result, the pushbutton switch is susceptible to chattering.

[Purpose of invention]

In view of the above-mentioned problems, this invention aims to provide a push-button switch that provides stable switch operation and has a high degree of freedom in design.

[Structure of the idea]

Therefore, in the present invention, the key top, the click dome, the elastic body, the movable contact, and the fixed contact are arranged in this order, the convex surface of the click dome is placed facing the elastic body, and the key top is pressed by pressing the key top. The pressing force is transmitted to the movable contact via the click dome and the elastic body, thereby causing the movable contact to come into contact with the fixed contact, and the reaction force of the elastic body when the key top is pressed down causes the click dome to clickly displace. The above objectives have been achieved.

That is, in the push-button switch of the present invention, the click dome is installed in the opposite direction to the conventional one, so that the movable contact contacts the fixed contact before the click dome is clicked. When the click dome is arranged in this manner, when the click dome is click-displaced, the pressing force on the movable contact decreases, but the reaction force accumulated in the elastic body causes the push-down force on the movable contact to decrease. Maintain contact with fixed contacts.

〔Example〕

Hereinafter, one embodiment of the push button type switch according to the present invention will be described in detail.

FIG. 1 shows a push-button switch (hereinafter simply referred to as "switch") of the present invention.

In this switch 30, a conductive path 34 is formed on the back plate 32, and a conductive path 34 is formed on the back plate 32.
A contact sheet 38 is placed on top of the contact sheet 38 via a spacer 36.
is installed. A conductive path 40 is formed on the lower surface of the contact sheet 38, and the contacts 34a, 40a of the conductive paths 34, 40 are arranged to face each other. Further, a base frame 42 is arranged above the spacer 36, and this base frame 4
2 has a hole 44 passing through in the vertical direction.
An elastic body 46 is disposed within this hole 44 on the contact sheet 38, and a key top 48 is further disposed on the elastic body 46. The elastic body 46 has a convex portion 46a extending in the vertical direction at its center, a disk portion 46b having a funnel-shaped cross section around the convex portion 46a, and a peripheral edge 46c of the disk portion 46b.
is held between the base frame 42 and the contact sheet 38. The lower end 46d of the convex portion 46a of the elastic body 46 is in contact with the contact sheet 38, and the convex portion 46a
The upper end 46e is the convex surface 50a of the click dome 50.
It is placed so that it touches the center.

Next, the operation of the above-mentioned switch 30 will be explained with reference to FIGS. 2 to 4, and the structure will also be explained in more detail.

In the inoperative state of this switch 30, the conductive path 4
The zero contact 40a is separated from the contact 34a of the conductive path 34, and the key top 48 is pushed upward together with the click dome 50 by the biasing force of the elastic body 46.

When the key top 48 is pressed from the initial position shown in FIG.
It is pressed into contact with and turns on. In the state shown in FIG. 3, the click dome 50 is slightly deformed, but has not yet performed a click action. and,
The convex portion 46a of the elastic body 46 is connected to the click dome 50.
is compressed between the convex surface 50a and the contact sheet 38. Furthermore, when the key top 48 is pressed from the state shown in FIG. 3, the click dome 50 causes a click action to rapidly expand the space between the contact sheet 38 and the click dome 50, as shown in FIG. The convex portion 46a of the elastic body 46 also expands due to the click action of the click dome 50, with both ends 46d and 46e in close contact with the convex surface 50a of the click dome 50 and the contact sheet 38 due to its own elastic force. , the pressure contact between the contact 40a and the contact 34a is not released, and the ON state is maintained. Furthermore, when the key top 48 is released from the press after the click operation, the key top 48 and the contact 40a
is returned to the initial position shown in FIG. 2 by the restoring force inherent in the click dome 50 and the elastic body 46.

FIG. 5 is a graph showing the relationship between the pressing force F applied to the key top 48 and the stroke S of the key top 48. As is clear from this graph, the pressure contact point between the contact 40a and the contact 34a, that is, the ON point C is , are set before the click operation of the click dome 50 (from point a to point b). Note that this ON point C can be set at an arbitrary stroke position of the key top 48 by changing the material of the elastic body 46.

In the above embodiment, the contact 40a of the conductive path 40 formed on the contact sheet 38 is brought into pressure contact with the contact 34a by the elastic body 46, but the present invention is of course not limited to the above embodiment. As shown in FIG. 6, in which the same parts as in the above embodiment are denoted by the same reference numerals, a contact 54 is directly attached to the lower end of the convex portion 46a of the elastic body 46, and this contact 54 is connected to a contact 58 formed on the printed wiring board 56. The pressure may be applied between 60 and 60 mm.

[Effect of idea]

As mentioned above, this device ensures that the movable contact and the fixed contact are in pressure contact from the click operation when the key top is pressed to the click operation when the key top is raised, so that the occurrence of chattering is minimized. Furthermore, by appropriately setting the elastic coefficient of the elastic body, the timing of the click operation can be changed, providing a large degree of freedom in design.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional perspective view of a push-button switch according to the present invention, FIGS. 2 to 4 are cross-sectional views showing the operation of the push-button switch according to the present invention, and FIG. 5 is a diagram showing the stroke of the key top. FIG. 6 is a cross-sectional perspective view of a push-button switch showing another embodiment, and FIGS. 7 to 9 are cross-sectional views showing conventional push-button switches. 30, 52...Push button switch, 34
a, 58, 60... Fixed contact, 40a, 54...
Movable contact, 46... elastic body, 48... key top, 50... click dome, 50a... convex surface.

Claims (1)

[Scope of utility model registration request] In a push-button switch, the displacement of a key top is transmitted to a movable contact via a click dome, and the movable contact is brought into pressure contact with a fixed contact to perform a switching operation. interposing an elastic body, arranging the convex surface of the click dome toward the elastic body, and pressing a key top to bend the elastic body and bring the movable contact into contact with the fixed part; A push-button switch characterized in that, when the key top is further pressed down, the click dome is click-operated by the reaction force of the elastic body, thereby holding both the contacts in a state in which they are in contact with each other.