JPH06251662A - Membrane contact sheet - Google Patents

Abstract

PURPOSE:To provide a membrane contact sheet of excellent durability wherein no excessive-force is applied to each of a movable contact and a stationary contact, by providing an elastic member of width reduced more than that of the notched portion of a spacer to the notched portion so that the elastic member may be laid at both end portions thereof above the notched portion via a movable contact film. CONSTITUTION:When a key top 19 is depressed, a movable contact 5a is abutted upon a stationary contact 6a to establish a closed-circuit condition between the movable contact 5a and the stationary contact 6a. When the key top 19 is further depressed from this closed-circuit condition, an elastic member 20 is gradually deformed elastically with absorbing the resultant impact force so as to make the key top 19 incapable of being depressed still further in the direction of an arrow. When the key top 19 is then released from pressure by operator's finger, the depressed face thereof is rotationally moved in the direction of an arrow D by elastic force of the elastic member 20 and consequently detached from the elastic member 20 on a movable contact film 5 while the movable contact film 5 is detached at its movable contact 5a fro the stationary contact 6a of a stationary contact film 6. As the result, an open-circuit condition is reestablished between the movable contact 5a and stationary contact 6a of a membrane contact sheet 23.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a membrane contact sheet used as a contact of a key switch.

[0002]

2. Description of the Related Art Conventionally, as a contact of a key switch, a movable contact film provided with a movable contact is pressed by a pressing surface to be arranged on a fixed contact film through a notch of a spacer. A membrane contact sheet is used in which the movable contact contacts the fixed contact.

The structure of a conventional membrane contact sheet will be described below with reference to the drawings. 10 is a vertical sectional view showing a conventional key switch, and FIG. 11 is an exploded perspective view showing the conventional key switch. In FIGS. 10 and 11, the key switch 1 is roughly composed of a membrane contact sheet 2 and a push button key.
3 and the reinforcing plate 4.

First, the membrane contact sheet 2 is composed of a movable contact film 5 formed by arranging a pattern of conductive ink on an insulating thin film such as a polyester film, and a fixed contact film paired with the movable contact film 5. 6 and a spacer 7 having a predetermined thickness and bonded between the movable contact film 5 and the fixed contact film 6 with an adhesive material or the like are laminated and integrated. It is attached with an adhesive or the like. In the arrangement pattern of the movable contact film 5 and the fixed contact film 6, the movable contact 5a and the fixed contact 6a are arranged so as to face each other. A notch 7a is provided in the spacer 7 at this portion, the movable contact 5a and the fixed contact 6a face each other, and a predetermined clearance is maintained between the movable contact 5a and the fixed contact 6a. The movable contact 5a
A push button key-3 is disposed above the fixed contact 6a and the fixed contact 6a.

The push button key-3 includes a key top 10 having a sliding pin 8 and a clamp claw 9 for preventing slipping off, and a sliding pin 8
Guide 11 for slidably supporting the arrow in the direction of arrow AB
And a key switch base 13 integrally formed with a plurality of clamp portions 12 accumulating the clamp claws 9, one end of which engages with the key top 10 and the other end of which engages with the slide guide 11.
It is composed of a cup rubber 14 that biases the key top 10 in the direction of arrow A. The movable contact film 5
The key switch base 13 and the key switch base 13 are fixed at a position not shown.

A conventional key switch 1 having the above structure
When the key is not pressed, the key top 10 is pushed up in the direction of arrow A by the elastic force of the cup rubber 14, the clamp claw 9 is accumulated in the clamp portion 12 and is held at the uppermost position, and the sliding pin 8 is The movable contact film 5 is held at a position slightly apart from it, and therefore the movable contact 5a and the fixed contact 6a are in an open state.

Next, the operation of the membrane contact sheet having the above structure when the key top 10 is pressed will be described. FIG. 12 is a longitudinal sectional view showing the operation of the conventional key switch. In FIG. 12, when the key top 10 is pushed down, the sliding pin 8 descends along the sliding guide 11 in the direction of arrow B, and the sliding pin 8 pushes down the movable contact film 5 in the direction of arrow B to bend it. Then, the movable contact 5a contacts the fixed contact 6a, and the movable contact 5a and the fixed contact 6a are closed. Even if you press the key top 10 from this state,
The sliding pin 8 does not descend further in the arrow B direction due to the contact between the movable contact 5a and the fixed contact 6a.

Next, when the finger is released from the key top 10 in the closed state, the sliding pin 8 is lifted in the direction of arrow A by the elastic force of the cup rubber 14, and the sliding pin 8 moves. And the movable contact 5a of the movable contact film 5 separates from the fixed contact 6a of the fixed contact film 6,
As a result, the space between the movable contact 5a of the membrane contact sheet 2 and the fixed contact film 6 returns to the open state.

[0009]

However, the membrane contact sheet having the above structure has the following problems. When the key top is pressed, the pressing force directly presses the membrane contact sheet by the pressing surface. Therefore, since the pressing surface of the key top is a rigid body, if the key top is pressed with excessive force, the impact force of the pressing surface causes cracks or peeling of the conductive ink forming the movable contact and the fixed contact. Sometimes occurred.

Further, there has been a problem that the function as a switch is impaired when a defect such as cracking or peeling occurs in the conductive ink.

The present invention is a membrane contact sheet having excellent durability, in which excessive force is not applied to the movable contact and the fixed contact.
The purpose is to provide

[0012]

In order to achieve the above object, the first means for solving the problems provided by the present invention is to press a key top, and press the key top through a notch portion of a spacer,
A membrane contact sheet in which the movable contact provided on the movable contact film comes into contact with the fixed contact provided on the fixed contact film.
Has a narrower width than the notch of the spacer,
Both ends of the elastic member that presses the movable contact through the notch of the spacer by the pressing surface are installed in the notch of the spacer.

According to a second solving means, the elastic member has a rod shape having a thickness thicker than the gap between the movable contact and the fixed contact, and the pressing surface of the key top has a width narrower than that of the notch. In addition to having the above, the elastic member intersects and abuts the elastic member.

[0014]

When the key top is lowered and the pressing surface presses and bends the elastic member of the movable contact film, the movable contact comes into contact with the fixed contact, and the movable contact and the fixed contact are closed.
At this time, since the elastic member absorbs the impact force of the pressing surface,
Since the impact force on the movable contact and the fixed contact is small and no excessive force is applied, cracking and peeling do not occur. Therefore, it is possible to provide a membrane contact sheet having excellent durability.

[0015]

First Embodiment An embodiment of the present invention will be described with reference to the drawings.
Elements common to the drawings are given the same reference numerals. FIG. 1 is a vertical sectional view showing a key switch according to a first embodiment of the present invention,
2 is an exploded perspective view showing the key switch of the first embodiment, and FIG. 3 is an exploded perspective view showing the membrane contact sheet of the first embodiment.

In FIG. 1, the key switch 15 is roughly composed of a membrane contact sheet 16, a push button key-3 and a reinforcing plate 4.
Composed of and.

First, as shown in FIGS. 1, 2 and 3, the membrane contact sheet 2 comprises a movable contact film 5 in which an array pattern is formed by conductive ink on an insulating thin film such as a polyester film. The fixed contact film 6 paired with the movable contact film 5 and the spacer 7 having a predetermined thickness and bonded between the movable contact film 5 and the fixed contact film 6 with an adhesive material or the like. Reinforcement plate 4 with integrated lamination
It is attached to the upper surface of the with an adhesive or the like. In the arrangement pattern of the movable contact film 5 and the fixed contact film 6, the movable contact 5a and the fixed contact 6a are arranged so as to face each other. A notch 7a is provided in the spacer 7 at this portion, the movable contact 5a and the fixed contact 6a face each other, and a predetermined clearance is maintained between the movable contact 5a and the fixed contact 6a. On the movable contact film 5 facing the movable contact 5a, an elastic member 17 formed of silicon rubber or the like and having a width narrower than the cutout portion 7a of the spacer 7 is provided so that both ends are bridged to the cutout portion 7a. It is provided in. A push button key is provided above the movable contact 5a and the fixed contact 6a.
3 are arranged.

The push button key-3 is a key top 10 having a long slide pin 18 and a clamp claw 9 for preventing slipping off, and a slide for slidably supporting the slide pin 18 in the directions of arrows AB. A key switch base 13 formed by integrally molding a plurality of moving guides 11 and a clamp portion 12 for accumulating the clamp claws 9, one end of which engages with the key top 10, and the other end of which engages with a sliding guide. And the cup rubber 14 that urges the key top 10 in the direction of arrow A. The movable contact film 5 and the key switch base 13 are fixed at a location not shown.

In the key switch 15 of the first embodiment having the above-mentioned structure, the key top 10 has the cup rubber 1 when not pressed.
The elastic force of 4 pushes it up in the direction of arrow A, the clamp claw 9 is accumulated in the clamp portion 12 and is held at the uppermost position, and the slide pin 8 is held at a position slightly apart from the movable contact film 5, and , Movable contact 5a and fixed contact 6
It is in an open state with a.

Next, the operation of the membrane contact sheet 16 having the above structure when the key top 10 is pressed will be described. FIG. 4 is a vertical sectional view showing the operation of the first embodiment while the key switch is being pressed, and FIG. 5 is a vertical sectional view showing the key switch pressing stop operation of the first embodiment. In FIG. 4, when the key top 10 is pushed down, the sliding pin 18 moves into the sliding guide 11.
When the sliding pin 18 pushes down the elastic member 17 of the movable contact film 5 in the direction of arrow B to bend the movable contact 5a, the movable contact 5a comes into contact with the fixed contact 6a and the movable contact 5a. The fixed contact 6a is closed. When the key top 10 is further pressed from this state, the elastic member 17 elastically deforms while absorbing the impact force, and finally, the key top 10 and the tip portion 11a of the sliding guide 11 are moved to the positions shown in FIG.
As shown in FIG. 3, the sliding pin 18 cannot be further lowered in the arrow B direction.

Next, when the finger is released from the key top 10 under the closed state, the sliding pin 18 is lifted by the elastic force of the cup rubber 14, and the sliding pin 18 is moved by the elastic member 17 of the movable contact film 5. The movable contact 5a of the movable contact film 5 separates from the fixed contact 6a of the fixed contact film 6 as a result, and as a result, the movable contact 5a of the membrane contact sheet 16 moves.
The state between a and the fixed contact 6a returns to the open state.

Second Embodiment Next, a second embodiment of the present invention will be described with reference to the drawings. The same parts as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted. FIG. 6 is an exploded perspective view showing the key switch of the second embodiment, and FIG. 7 is the key of the second embodiment.
FIG. 8 is a perspective view showing the top, and FIG. 8 is a vertical sectional view showing the key switch of the second embodiment. The second embodiment differs from the first embodiment in that the elastic member 20 is connected to the movable contact 5a.
The pressing surface 21 of the key top 19 has a width narrower than that of the cutout portion 7a and is in contact with the elastic member 20 while intersecting with the elastic member 20.

More specifically, as shown in FIG. 6, the key switch 22 is mainly composed of a membrane contact sheet 23, a push button key 24 and a reinforcing plate 4.

First, the membrane contact sheet 23 has a movable contact film 5, a fixed contact film 6 paired with the movable contact film 5, and a predetermined thickness. 6 and a spacer 7 joined together by an adhesive or the like between 6 and 6 are laminated and integrated.
It is attached to the upper surface of the with an adhesive or the like. In the arrangement pattern of the movable contact film 5 and the fixed contact film 6, the movable contact 5a and a fixed contact (not shown) are arranged in a facing state, respectively. At this portion, the spacer 7 has a cutout portion 7a.
Is provided, the movable contact 5a and the fixed contact 6a face each other,
A predetermined clearance is maintained between the movable contact 5a and the fixed contact 6a. The movable contact film 5 facing the movable contact 5a is formed of silicon rubber or the like,
A rod-shaped elastic member 20 thicker than the gap between the fixed contact 6a and the fixed contact 6a is provided, and the length of the elastic member 20 is set to be longer than the diameter of the cutout portion 7a of the spacer 7. A push button key 24 is arranged above the movable contact 5a and the fixed contact 6a.

The push button key 24 is provided with a rotary shaft 25 rotatably held in a bearing 29 provided on the cover 26 in the directions of arrows CD, and the push surface 21 is formed into a rib shape for molding. The key top 19 and the stopper 28 attached to the key top 19 for preventing the key top 19 from projecting from the opening 27 of the cover 26. The pressing surface 21 of the key top 19 has a width narrower than the cutout portion 7a of the spacer 7, and the key top 1
The pressing surface 21 of 9 and the elastic member 20 are arranged such that the elastic member 20 crosses the pressing surface 21 of the key top 19 and abuts when the key top 19 is pressed.

As shown in FIG. 8, the key switch 22 of the second embodiment having the above-mentioned structure is in the key top 1 when not pressed.
9 is pushed up in the direction of arrow A by the elastic force of the elastic member 20, and the stopper 28 is locked in the opening 27 and held at the uppermost position. Therefore, the movable contact 5a and the fixed contact 6a
It is open between and.

Next, the operation of the membrane contact sheet 23 having the above structure when the key top 19 is pressed will be described. FIG. 9 is a vertical sectional view showing the operation of the key switch of the second embodiment.

In FIGS. 8 and 9, when the key top 19 is pushed down, the key top 19 rotates about the rotary shaft 25 as a fulcrum in the direction of arrow C, and the pushing surface 21 moves the elastic member 20 toward the arrow B.
When it is pushed down in the direction to bend it, the movable contact 5a becomes fixed contact 6
It comes into contact with a and the movable contact 5a and the fixed contact 6a are closed. If you press the key top 19 further from this state,
The elastic member 20 elastically deforms while absorbing the impact force, and finally, the one end portion 19a of the key top 19 and the movable contact film 5 come into contact with each other, and the key top 19 is further moved in the direction of the arrow B. Is not allowed to descend.

Next, when the finger is released from the key top 19 under the closed state, the pressing surface 21 is rotated in the direction of the arrow D by the elastic force of the elastic member 20, and the pressing surface 21 of the movable contact film 5 is moved. The movable contact 5a of the movable contact film 5 moves away from the elastic member 19 and the fixed contact 6a of the fixed contact film 6 moves.
And the movable contact 5a and the fixed contact 6a of the membrane contact sheet 23 are returned to the open state.

[0030]

Since the present invention is configured as described above, it has the following effects. Even if the pressing surface of the key top, which is a rigid body, is pressed with an excessive force, the impact force of the pressing surface is absorbed by the elastic member, so that the conductive ink is free from defects such as cracks and peeling, and the switch is used as a switch. The function of will not be impaired. Therefore,
It is possible to obtain stable opening and closing of the switch.

Further, since the elastic member is provided at a position where it crosses and comes into contact with the pressing surface of the key top when the key top is pressed, the size of the cross section of the pressing surface depends on the notch of the spacer. I am not bound by the size.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a key switch according to a first embodiment of the present invention.

FIG. 2 is an exploded perspective view showing the key switch of the first embodiment.

FIG. 3 is an exploded perspective view showing a membrane contact sheet of the first embodiment.

FIG. 4 is a vertical cross-sectional view showing an operation during pressing of the key switch according to the first embodiment.

FIG. 5 is a vertical cross-sectional view showing a key switch pressing stop operation of the first embodiment.

FIG. 6 is an exploded perspective view showing a key switch of a second embodiment.

FIG. 7 is a perspective view showing a key top according to a second embodiment.

FIG. 8 is a vertical sectional view showing a key switch according to a second embodiment.

FIG. 9 is a vertical sectional view showing the operation of the key switch of the second embodiment.

FIG. 10 is a vertical sectional view showing a conventional key switch.

FIG. 11 is an exploded perspective view showing a conventional key switch.

FIG. 12 is a vertical cross-sectional view showing the operation of a conventional key switch.

[Explanation of symbols]

 5 Movable contact film 5a Movable contact 6 Fixed contact film 6a Fixed contact 7 Spacer 7a Notch part 10, 19 Key top 16, 23 Membrane contact sheet 17, 20 Elastic member 21 Pressed surface

Claims (2)

[Claims] 1. A key top is depressed, and the depressed surface of the key top causes the movable contact provided on the movable contact film to come into contact with the fixed contact provided on the fixed contact film through the notch of the spacer. In the membrane contact sheet, both ends of the elastic member that has a width narrower than the notch of the spacer and presses the movable contact through the notch of the spacer by the pressing surface Membrane contact sheet characterized by being installed in the section. 2. The elastic member is in the form of a rod having a thickness thicker than the gap between the movable contact and the fixed contact, and the pressing surface of the key top has a width narrower than that of the notch and intersects with the elastic member. 2. The membrane contact sheet according to claim 1, which abuts against each other.