JPH07141958A - Pressure sensitive switch - Google Patents

Abstract

PURPOSE:To provide a pressure sensitive switch which generates a good electric continuity, when a pressure is applied, and with which a sure insulated condition can be held with no pressure applied even in such a case where the switch is serving in curved condition. CONSTITUTION:A pair of electroconductive members 1, 1' in which flexible conductors 2, 2' are inserted, are arranged in parallel in such a condition as insulated from one another. An elastic electroconductive member 3 insulated from the conductive members 1, 1' is installed as confronting them with a gap 4 is reserved in between, and the whole of them is enclosed with an elastic insulative member 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a pressure-sensitive switch in which a good conductive state is obtained when pressure is applied and reliable insulation is maintained when no pressure is applied.

[0002]

2. Description of the Related Art In recent years, labor saving and unmanning have progressed in all fields, and various types of switches and sensors have been developed. However, start and stop switches for factory equipment, crime prevention, medical care, civil engineering, daily life peripherals, etc. A pressure switch is used as the measurement and detection sensor.

For example, as shown in FIG. 2, it is known that gaps 14 and 14 'are formed between a pressure conductive rubber 11 and flat braided wires 12 and 12', and the whole is covered with an insulating rubber 13. (JP-A-61-161621).

However, in this switch,
When the local pressure is applied, there is a problem that the flat braided wires 12 and 12 'do not return to their original shapes while being deformed, and current flows even in the non-pressurized state.

Therefore, as shown in FIG. 3, the present inventor first made the pair of conductive members 21 and 21 ′, into which the flexible conductors 22 and 22 ′ are inserted, to face each other with a gap 24 between them, and A pressure-sensitive switch in which the above is covered with an elastic insulating member 23 has been proposed (Japanese Patent Application No. 3-155595).

Although this switch can solve the above-mentioned problems, when it is used by being attached to a curved surface such as a bumper of an automobile, the void 24 is crushed by bending the switch, and the conductive member 21, 21 '
It has been found that a new problem arises in that the switch contacts and becomes conductive, and a current always flows from one of the flexible conductors 22 and 22 'to the other, thereby failing to perform the switch function.

[0007]

SUMMARY OF THE INVENTION Therefore, according to the present invention, even when it is attached to a curved surface such as a bumper of an automobile and used in a curved state, a good conduction state can be obtained at the time of pressurization. It is an object of the present invention to provide a pressure-sensitive switch in which a reliable insulating state is maintained when pressure is applied.

[0008]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventor has arranged an elastic conductive member having good expandability on the side that is expanded by bending, and The present invention has been completed in consideration of arranging the conductive member having the inferior flexible conductor inserted therein on the side contracted by bending.

That is, according to the present invention, a pair of conductive members having a flexible conductor inserted therein are arranged in parallel in a state of being insulated from each other, facing the pair of conductive members and insulated from the pair of conductive members. In the pressure-sensitive switch, an elastic conductive member is arranged via a gap and the whole is covered with an elastic insulating member.

[0010]

According to the switch of the present invention, a pair of conductive members having a flexible conductor inserted therein are arranged in parallel with each other in an insulated state, facing the pair of conductive members and insulated from the pair of conductive members. Since the elastic conductive member is arranged through the gap and is entirely covered with the elastic insulating member, in the unpressurized state, the pair of conductive members are completely insulated and a current flows through the flexible conductor. There is no such a case, and it is possible to avoid the danger of heat generation and unnecessary current consumption.

Further, since it is composed of a conductive member having a flexible conductor inserted therethrough, an elastic conductive member, and an elastic insulating member, it is excellent in bendability in any direction and is resistant to local pressure. However, the restoring force is strong, the original shape is not restored after the pressurization, and there is no problem that the electric current flows even in the non-pressurized state.

When the switch of the present invention is pressed, the void is crushed and the pair of conductive members and the elastic conductive member come into contact with each other,
The pair of conductive members are brought into conduction via the elastic conductive member, and a current flows from any one of the flexible conductors to the other to operate as a switch.

When the switch of the present invention is used in a bent state, the elastic conductive member can be bent according to the deformation by bending the switch so that the side on which the elastic conductive member having high stretchability is arranged is the outer side. Stretches and voids do not collapse. Therefore, the pair of conductive members are kept insulated from each other, and there is no problem that a current always flows through the flexible conductor and the switch function is not fulfilled.

However, in the conventional pressure sensitive switch shown in FIG. 3, the flexible conductors 22 and 22 'are attached to the conductive members 21 and 21'.
Since it is inserted, the expandability that can follow the bending is not obtained, and the void 24 is crushed by the bending, and the conductive members 21 and 21 'come into contact with each other and become conductive.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail below with reference to the drawings. FIG. 1 is a perspective view showing an example of the pressure-sensitive switch of the present invention, in which 1 and 1'are conductive members, 2 and 2'are flexible members inserted through the conductive members, 3 are elastic conductive members, and 4 respectively. Is a space formed between the conductive members 1 and 1'and the elastic conductive member 3, and 5 is an elastic insulating member that covers the entire space.

A pair of conductive members 1 and 1'through which the flexible conductors 2 and 2'are inserted are arranged in parallel in a mutually insulated state, and are opposed to the pair of conductive members 1 and 1 '. An elastic conductive member 3 which is insulated from the conductive members 1 and 1 ′ is arranged via a gap 4.

As the conductive members 1 and 1 ', C or Ni,
Natural rubber or synthetic rubber containing metal powder such as Ag or Pt is used, and C-containing silicone rubber is usually used. Examples of the flexible conductors 2 and 2'include core wires for electric wires and plate conductors made of a conductive material such as phosphor bronze, and twisted wires made of a plurality of conductor wires are preferably used. As the elastic conductive member 3, the same elastic body as that used for the conductive members 1 and 1'is used, and usually C-containing silicone rubber is used.

Further, as the elastic insulating member 5, ethylene-propylene rubber, chloroprene rubber, nitrile rubber,
Synthetic rubbers such as silicone rubber are usually used, and silicone rubber is particularly preferably used.

The surfaces of the conductive members 1 and 1'and the elastic conductive member 3 which face each other are easily separated when the pressure is released and the original shape is restored after the pressure contact between them. Therefore, it is desirable to form the unevenness 6 in advance.

The size of the void 4, that is, the distance between the surfaces of the conductive members 1 and 1'and the surface of the elastic conductive member 3 may be appropriately selected according to the purpose of use, but is usually 0.5 to 5. 0 mm
It should be about.

Further, the elastic insulating member which insulates the pair of conductive members 1 and 1'from each other is easily deformed when a part of the elastic insulating member 5a is applied to the switch, but is not deformed only by bending. It is preferable to have a thickness of, for example, 0.5 to 5.0 mm so as to project into the space 4 because it can prevent the space 4 from being crushed when the switch is used in a curved state.

When pressure is applied to this switch, the gap 4 is crushed, the pair of conductive members 1, 1'and the elastic conductive member 3 contact each other, and the conductive member 1 and the conductive member 1'separate the elastic conductive member 3. Conduction is conducted through the flexible conductors 2 and 2 ', and a current flows from one of the flexible conductors 2 and 2'to the other. When the pressure is released, the void 4 is restored to its original shape by the restoring force of the elastic insulating member 5, the conductive members 1, 1 ′ and the elastic conductive member 3 are separated, and the conductive member 1
The conductive state between the conductive member 1'and the conductive member 1'is released.

When this switch is used in a bent state, if the side where the elastic conductive member 5 is located is bent outward, the elastic conductive member 5 expands in accordance with the deformation and the void 4 is formed. There is no such thing as a crush. In particular, a part 5 of the elastic insulating member that insulates the conductive members 1, 1'from each other.
When a is projected into the void 4, the effect of preventing the void 4 from collapsing is further enhanced.

For example, as the conductive member and the elastic conductive member, a thermosetting C-containing conductive silicone rubber having a hardness of 70 (volume resistivity 3 to 5 Ω · cm), and as the elastic insulating member,
A heat-curable silicone rubber having a hardness of 70 is used, and as the flexible conductor, 34 element conductor wires having a diameter of 0.05 mm are twisted together. When the elastic conductive member and the elastic insulating member are simultaneously extruded and cured by heating, a pressure sensitive switch as shown in FIGS. 1 and 2 is obtained.

[0025]

According to the pressure-sensitive switch of the present invention, it is excellent in flexibility in any direction, and has a strong restoring force against local pressure. There is no problem that the current flows in the non-pressurized state without restoring the shape.

Further, even if the pressure-sensitive switch of the present invention is used in a bent state, there is no problem that the gap is crushed and the pair of conductive members are conducted, and the switch is activated, and the bumper of an automobile is not affected. It can be used by attaching it to a curved surface such as.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a pressure-sensitive switch of the present invention.

FIG. 2 is a perspective view showing an example of a conventional pressure sensitive switch.

FIG. 3 is a perspective view showing another example of a conventional pressure sensitive switch.

[Explanation of symbols]

 1, 1'conductive member 2, 2'flexible member 3 elastic conductive member 4 void 5 elastic insulating member

Claims (5)

[Claims] 1. An elastic conductive member in which a pair of conductive members inserted with a flexible conductor are arranged in parallel in a state of being insulated from each other, facing the pair of conductive members and insulated from the pair of conductive members. A pressure-sensitive switch, characterized in that it is disposed through a gap and is entirely covered with an elastic insulating member. 2. The pressure-sensitive switch according to claim 1, wherein the flexible conductor is a stranded wire composed of a plurality of conductor wires. 3. The pressure sensitive switch according to claim 1, wherein the conductive member is a conductive silicone rubber. 4. The pressure-sensitive switch according to claim 1, wherein the elastic conductive member is conductive silicone rubber. 5. The sense switch according to claim 1, wherein the elastic insulating member is silicone rubber.