JPH05190052A - Key switch - Google Patents

Abstract

PURPOSE:To reduce collision sound generated when a key top returns by absorbing contact energy between the respective engaging pieces of a guide cylinder and the springing out prevention portion of a plunger by means of the deflection of the springing out prevention portion. CONSTITUTION:A key top returns to an original position before depressing through the contact of the springing out prevention portion 11 contact part 16 of a plunger 10 and the guide cylinder 8 engaging part 12 of a housing 9. Since the portion 11 is deflected by energy produced through the return force of a moving portion 5, when the part 16 of the portion 11 is brought into contact with the piece 12 of the cylinder 8, the energy during the process of the collision thereof is absorbed and relieved. And since the part 16 and the piece 12 are put in line contact, a contact area becomes extremely small so that generated sound caused by the collision becomes small. Thereby the collision sound generated during the process of key top return can be made extremely small than before, since the contact energy between the respective pieces 12 of the cylinder 8 and the portion 11 of the plunger 10, caused through the return force of the moving portion of a rubber during the process of the key top return, is absorbed and relieved by the deflection of the portion 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a key switch,
In particular, the present invention relates to a key switch of a keyboard widely used as an input device for information processing equipment, office equipment, industrial equipment and the like.

[0002]

2. Description of the Related Art Conventionally, this kind of key switch has been constructed as shown in FIGS. 9, 10 and 11, for example.

In the figure, reference numeral 21 denotes a membrane sheet laminated on a fixed plate 22, which is provided with a contact portion composed of a movable contact 23 and a fixed contact 24 which are arranged to face each other in the thickness direction. On the membrane sheet 21, a rubber 26 provided with a movable portion 25 capable of pressing the contact portion is laminated,
The rubber 26 includes a rectangular guide cylinder 27 surrounding the movable portion 25.
The housing 28 provided with is mounted. Guide tube 2
The escape prevention portion 3 that abuts the locking pieces 29 on both sides of the escape prevention portion 7.
The escape is prevented by 0, and the plunger 31 is fitted in such a manner that it can move up and down. A key top 32 is detachably attached to the plunger 31.

In FIG. 7, 33 is a fixed plate 2.
2, screws for fixing the membrane sheet 21 and the rubber 26.

When the plunger 31 and the movable portion 25 are pushed down by the operation of the key top 32, the contact portion is switched on, and when the key top 32 is released, the restoring force of the depressed movable portion 25 causes the contact portion. Is switched off, and the plunger 31 and key top 3
2 is configured to return to the position before pressing.

[0006]

In this conventional key switch, the escape preventing portion for preventing the escape of the plunger and the respective locking pieces of the plunger are in surface contact with each other. In the above, there was a problem that the plunger that received the restoring force of the movable part of the rubber returned to the state before it was pressed, and a loud collision sound was generated when the key top was returned.

[0007] Therefore, an object of the present invention is to provide a key switch capable of reducing the collision noise generated when the key top is returned.

[0008]

A key switch according to the present invention is laminated on a membrane sheet laminated on a fix plate, and a rubber provided with a movable portion capable of pressing a contact portion of the membrane sheet and mounted on the rubber. The housing is provided with a guide tube surrounding the movable part, and the guide tube of the housing is fitted in the guide tube so as to prevent the escape from coming off by the escape prevention parts that come into contact with the locking pieces on both sides of the guide tube, and the upper end portion. And a plunger having a key top attached thereto, wherein the escape portion of the plunger has flexibility.

It is preferable that the escape prevention portion includes a contact portion that comes into line contact with each locking piece of the guide cylinder.

[0010]

In the above means, when the key top is returned, the contact energy between each locking piece of the guide cylinder and the escape prevention portion of the plunger, which is generated by the restoring force of the movable portion of the rubber, is changed by the deflection of the escape prevention portion. Absorption is eased.

Further, since the escape prevention portion is provided with the contact portion which comes into line contact with each locking piece, the contact area between each locking piece and the escape prevention portion becomes extremely small.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

1, FIG. 2, FIG. 3 and FIG. 4 are an exploded perspective view of an embodiment of the present invention, a perspective view of a main portion, a plan view of the main portion and a front view of a half section of the main portion.

The fixed plate 1 has a membrane sheet 4 provided with a contact portion composed of a movable contact 2 and a fixed contact 3, which are arranged to face each other in the thickness direction (vertical direction in FIG. 4).
And a rubber 6 provided with a movable part 5 capable of pressing the contact part
Are sequentially laminated and are fixed by screws 7.

A housing 9 provided with a rectangular guide cylinder 8 surrounding the movable part 5 is placed on the rubber 6, and the movable part 5 of the rubber 6 is pushed into the guide cylinder 8 of the housing 9. The plunger 10 that is brought into contact with the guide pieces 8 has the flexible escape prevention portions 11 brought into contact with the locking pieces 12 protruding from both sides (left and right sides in FIG. 3) in the guide tube 8 from below. It is fitted in such a way that it can move up and down while preventing it from coming out of the tube 8. The plunger 10 has a U-shaped plunger body 13 that connects the bottoms of front and rear walls parallel to the long side of the guide cylinder 8, and a key to which a key top 14 is detachably attached at the center of the bottom. A top mounting post 15 is erected. As shown in detail in FIG. 2, both upper end portions of the front and rear walls of the plunger body 13 are connected by the T-shaped escape preventing portions 11, and the lower end portions of the escape preventing portions 11 are A contact portion 16 having a triangular cross section is provided in line contact with each locking piece 12 of the guide cylinder 8. The contact portion 16 allows the escape prevention portion 11 to move by bending, and thus the plunger main body 13 It is loosely fitted in a hole 17 provided at the bottom of the.

In the key switch having the above structure, when the key top 14 is pushed with a finger, the movable portion 5 of the rubber 6 pushes the contact portion of the membrane sheet 4 as the plunger 10 is pushed down, and the movable contact 2 is fixed. The contact point 3 is pressed and brought into contact, electricity flows through the membrane sheet 4, and a switch-on signal is obtained.

Then, when the finger is released from the key top 14, the plunger 10 is pushed up by the restoring force of the pushed down movable portion 5 of the rubber 6 to return to its original shape, and the escape preventing portion of the plunger 10 is prevented. By the contact between the contact portion 16 of 11 and the locking piece 12 of the guide tube 8 of the housing 9, the key top 14 is returned to the position before the depression.

When the contact portion 16 of the escape prevention portion 11 and the locking piece 12 of the guide tube 8 come into contact with each other, the escape prevention portion 11 bends due to the energy generated by the restoring force of the movable portion 5, and the energy at the time of the collision. Is absorbed and relaxed, and the contact portion 16 and the locking piece 12 are in line contact with each other, and the contact area is extremely small, so that the sound generated by the collision is significantly reduced.

5, FIG. 6, FIG. 7 and FIG. 8 are an exploded perspective view of a key switch of another embodiment of the present invention, a perspective view of a main portion, a plan view of the main portion and a front view of a half section of the main portion. is there.

In the key switch of this embodiment, the flexible escape prevention portions 110 of the plunger 10 are provided upright on both sides of the bottom portion of the plunger main body 13 in an L shape, and the upper portion thereof. To form a contact portion 111 that can be in line contact with the lower surface of the locking piece 12 of the guide tube 8 by being curved in an S shape.
And the plunger body 13 below the contact portion 111
The bottom portion of the device is appropriately cut out to allow the escape prevention unit 110 to bend.

Since the other constructions and operational effects are almost the same as those in FIGS. 1 to 4, the same constituent members and the like are designated by the same reference numerals and the description thereof will be omitted.

[0022]

As described above, according to the key switch of the present invention, each locking piece of the guide cylinder and the escape prevention portion of the plunger caused by the restoring force of the movable portion of the rubber when the key top is returned. Since the contact energy with and is absorbed and relaxed by the flexure of the escape prevention portion, the collision noise generated at the time of returning the key top can be significantly reduced as compared with the conventional case.

Further, since the escape prevention portion is provided with the contact portion which comes into line contact with each locking piece, the contact area between each locking piece and the escape prevention portion becomes extremely small, so that the collision noise is further reduced. can do.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a key switch according to an embodiment of the present invention.

FIG. 2 is a perspective view of a main part of a key switch according to an embodiment of the present invention.

FIG. 3 is a plan view of a main part of a key switch according to an embodiment of the present invention.

FIG. 4 is a front view, in half cross section, of a main part of a key switch according to an embodiment of the present invention.

FIG. 5 is an exploded perspective view of a key switch according to another embodiment of the present invention.

FIG. 6 is a perspective view of a main part of a key switch according to another embodiment of the present invention.

FIG. 7 is a plan view of a main part of a key switch according to another embodiment of the present invention.

FIG. 8 is a front view, in half cross section, of a main part of a key switch according to another embodiment of the present invention.

FIG. 9 is an exploded perspective view of a conventional key switch.

FIG. 10 is a plan view of a main part of a conventional key switch.

FIG. 11 is a half cross-sectional plan view of a main part of a conventional key switch.

[Explanation of symbols]

 1 Fix plate 2 Movable contact 3 Fixed contact 4 Membrane sheet 5 Movable part 6 Rubber 7 Screw 8 Guide tube 9 Housing 10 Plunger 11 Escape prevention part 12 Engagement piece 13 Plunger body 14 Keytop 15 Keytop mounting post 16 Contact Part 17 Hole 110 Escape prevention part 160 Contact part

Claims (2)

[Claims] 1. A rubber laminated with a membrane sheet laminated on a fixed plate and provided with a movable portion capable of pressing a contact portion of the membrane sheet, and a guide cylinder mounted on the rubber and surrounding the movable portion. Housing,
A key switch having a plunger having a key top attached to the upper end of the guide tube of the housing, the escape prevention portion abutting the locking pieces on both sides of the housing prevents the escape and prevents the escape. A key switch, wherein the escape prevention portion of the plunger has flexibility. 2. The key switch according to claim 1, wherein the escape prevention portion includes a contact portion that comes into line contact with each locking piece of the guide cylinder.