JP3046785B2 - Push-on switch - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a push-on switch. 2. Description of the Related Art Conventionally, as shown in FIG. 4, fixed contacts 2 and 2 are formed on a substrate 1 and a movable contact 3 is held on the substrate 1 at a predetermined interval above the fixed contacts 2. There has been proposed a push-on switch in which a cover member 4 having a dome portion 4a made of a material having elasticity is fixed. In this switch, when a pressing force is applied from above the dome portion 4a, the dome portion 4a is deformed, and the movable contact 3 comes into contact with the fixed contacts 2 and 2, and electrical conduction between the fixed contacts is performed. When the pressing force applied to the dome portion 4a is released, the dome portion 4a returns to its original state by its own elastic force, and the electrical conduction between the fixed contacts 2 is interrupted. In a conventional push-on type switch, a movable contact 3 and a fixed contact 2 are simply used.
However, there is a problem that there is almost no click feeling because the surface 2 only makes surface contact. Therefore, in a conventional switch,
There is a problem that the operator repeatedly performs the switch operation because there is no clicking feeling. Accordingly, Japanese Utility Model Application Laid-Open No. 58-150230 and
No. 57-55124.
Switches using tact metal plates, such as
was suggested. With these conventional push-on switches
Is used to ensure contact with the center contact.
A through hole is formed in the center of the dish-shaped portion of the metal plate. I
However, in the conventional structure, the center of the dish
Since the through hole is cut out, the inner peripheral edge of the through hole
Edge at the boundary between the inner surface of the through hole and the inner surface of the dish-shaped part
Are formed. This edge is where the switch action occurs
Each time, the surface of the center contact is shaved,
When the thickness of the contact is thin and the strength is low,
Conductive failure occurs due to less conductive members in contacting parts
There is a possibility that. Also, the plate-shaped part can be moved freely
When the amount of moving conductive powder increases, a short-circuit
May cause a switch malfunction.
You. An object of the present invention is to achieve normal switch operation with a simple configuration.
It is to provide a push-on type switch which can maintain the following. According to the present invention, in order to solve the above-mentioned conventional problems, a center contact 20a and an end contact 20b are formed on an insulating substrate 10 and an outer peripheral edge is formed. A reversible operable dish-shaped portion 30 partially curved so as to abut the end contact and protrude away from the substrate.
The tact metal plate 30 having “a” was placed on the substrate 10.
A through hole 30c is formed in the center of the dish-shaped part of the tact metal plate.
Have been. And contact with the surface of tact metal plate 30
An insulating cover member 40 is fixed to the substrate 10 so as to cover the surface.
Set. In the present invention, especially in the inner peripheral portion of the through hole 30c.
A curved surface 30d is formed. Forming a curved surface such as this
Then, the inner peripheral edge of the through hole may cut the central contact.
Since it disappears, continuity failure occurs and short-circuit between contacts
Can be prevented from occurring, and the normal switch
Switch operation can be maintained for a long period of time. Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a sectional view of an embodiment in which the present invention is applied to a membrane switch. In FIG. 1, reference numeral 10 denotes a substrate having an insulating property, and a flexible substrate having flexibility may be used depending on the application. Substrate 10
As shown in FIG. 2, a central contact 20a, an end contact 20b, a jumper wire 20c, and the like are formed using a conductive paint such as copper foil, silver paint, or carbon. As the conductive paint, it is preferable to use an epoxy resin-based, phenolic resin-based, melamine resin-based, or polyimide resin-based paint containing a conductive powder such as silver or carbon. The central contact 20a is
Through-hole conductor 20e provided through substrate 10
The electrode 20f is formed at the other end of the through-hole conductor 20e. Jumper wire 2
An overcoat 20d is formed on 0c using an appropriate material such as an epoxy resin. In the drawings,
For easy understanding, the thickness of the contacts 20a and 20b is exaggerated. In FIG. 1 and FIG. 3, reference numeral 30 denotes a dish-shaped portion 30a which is curved so as to protrude in a direction away from the substrate 10 and which can be inverted, and is formed continuously on the outer periphery of the dish-shaped portion 30a. It is a tact metal plate comprising a flange 30b. The tact metal plate 30 is placed on the substrate 10 such that the outer peripheral edge of the dish-shaped portion 30a and the flange portion 30b always contact the end contact 20b. The end of the flange portion 30b can be soldered to the end contact 20b to facilitate positioning, but in this case, the soldering is performed to such an extent that the deformation of the dish portion 30a is not hindered. The outer peripheral edge of the dish 30a, that is, the flange 30
b and the connecting portion between the dish portion 30a have a curved surface or roundness 3
0e is formed. Further, a through hole 30c is formed in the center of the dish-shaped portion 30a, and a curved surface or roundness 30d is also provided on the inner peripheral portion of the through hole 30c. The roundness 30d of the inner peripheral portion of the through hole 30c is obtained by, for example, fixing the tact metal plate 30 having the through hole formed therein to a jig, inserting a punch having a sharp end into the through hole, pushing up, and performing drawing. It is formed. Furthermore, the dish-shaped portion 30a
At the position near the flange portion 30b, elongated through holes 30f and 30g extending in the circumferential direction are formed. When forming these through-holes 30f and 30g, before forming the dish-shaped portion 30a, the through-holes 30f and 30g are previously placed at predetermined positions on the flat metal plate which is the material of the tact metal plate.
0 g is formed by punching. The through-holes 30c, 30f and 30g are formed by
When it is deformed by the pressing force in the direction toward zero, it has a function of releasing air in a space formed between the dish-shaped portion 30a and the substrate 10 from the space. Reference numeral 40 denotes an insulating cover member made of a synthetic resin made of, for example, polyester, polyethylene terephthalate, etc., having insulating properties and flexibility. The insulating cover member 40 is fixed to at least the substrate 10 using an adhesive so as to come into contact with and cover the surface of the tact metal plate. The flange portion 30b and the dish-shaped portion 30a are not bonded to the insulating cover member 40, and in this embodiment, the dish-shaped portion 3
In the state in which the insulating cover member 40a is not deformed,
A slight gap or space g is formed in a part between the plate-shaped portion 30a. Although only one switch is shown in FIG. 1, a plurality of switches having the structure shown in FIG. The switch of the present embodiment can be pressed directly with a finger from above the insulating cover member 40, but if necessary, a flexible flat plate as shown by a dashed line is placed on the insulating cover member 40. It is also possible to provide a pressing member 50 in the shape of a circle. When the switch operation is performed, the dish-shaped portion 30
The center part of a is pressed with a finger from above the insulating cover member 40. At the stage of applying the pressing force, the plate 30a and the substrate 1
Since the air in the space formed between 0 and 0 mainly passes through the through holes 30f and 30g into the gap g, the dish-shaped portion 30a is easily deformed. When the dish 30a is deformed, a clear click feeling is transmitted to the fingertip of the operator. When the operator releases his / her finger, the dish-shaped portion 30a performs a reversing operation and returns to the state shown in FIG. At this time, the air in the gap g passes through the through holes 30c, 30f and 30g and returns to the space formed between the dish 30a and the substrate 10, so that the dish 30a is quickly returned to its original state. Return to. In the above embodiment, the dish-shaped portion 30a
The rounded portions 30d and 30e are formed between the outer peripheral edge of the dish-shaped portion 30a even when the pressing operation is performed and the tact metal plate 30 is deformed. In addition, it is possible to prevent the end contact 20b and the center contact 20a from being scraped by the peripheral portion of the through hole 30c, thereby preventing the occurrence of poor conductivity. In this embodiment, the dish-shaped part of the tact metal plate is
When the pressing force is applied to deform the dish, the air in the space formed between the dish and the substrate is moved into the space formed between the dish and the insulating cover member. A through hole or cutout is formed so that the air in the space formed between the dish and the board does not hinder the dish, and the dish-shaped part of the tact metal plate is smoothly applied without applying a large pressing force. Can be transformed into In the above embodiment, the tact metal plate 30
Is used having a flange portion 30b as
A tact metal plate having only the dish portion 30a may be used. In this case, a notch of an appropriate shape may be formed on the outer peripheral edge of the dish-shaped portion, and air may be vented from the space formed between the dish-shaped portion and the substrate. Further, the position of the through hole or the notch for venting air may be anywhere as long as it does not hinder the deformation operation of the tact metal plate, and is not limited to the above embodiment. According to the present invention, the central part of the tact metal plate is provided.
A curved surface is formed on the inner periphery of the through hole
As a result, the inner peripheral edge of the through hole does not cut the central contact.
Malfunctions and short-circuits between contacts
Can be prevented from producing a normal switch
Operation can be maintained for a long time.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view showing one embodiment of the present invention. FIG. 2 is a partial perspective view showing one embodiment of a substrate used in the embodiment of FIG. FIG. 3 is a plan view of a tact metal plate used in the embodiment of FIG. FIG. 4 is a cross-sectional view showing a configuration of a conventional switch. [Description of Signs] 10 Insulating substrate 20a Central contact 20b End contact 30 Tact metal plate 30a Dish 30b Flange 30c, 30f, 30g Through hole 40 Insulating cover member

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yozo Ohara 3158 Shimookubo, Osawano-cho, Kamishinkawa-gun, Toyama Prefecture Inside Hokuriku Electric Industry Co., Ltd. 58-150230 (JP, U) Japanese Utility Model Showa 57-55134 (JP, U) Japanese Utility Model Utility Model Showa 61-100845 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01H 13/52 H01H 13/48

Claims (1)

(57) [Claims] An insulating substrate on which a center contact and an end contact are formed; and an outer peripheral portion disposed on the substrate so as to abut on the end contact and protruding in a direction away from the substrate. A tact metal plate (30) having a curved reversible dish-like portion; and a flexible insulating cover member which is in contact with and covers the surface of the tact metal plate and is fixed to the insulating substrate ( 40), and a through hole (30 ) is formed in the center of the dish-shaped portion of the tact metal plate.
c) is a push-on switch formed with
And a curved surface (30d) on the inner peripheral portion of the through hole (30c).
A push-on type switch, characterized in that a switch is formed .