JPH0448588Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Technical Field of the Invention) The present invention relates to a key switch, and particularly relates to a structure for attaching a cup-shaped rubber contact to a switch base.

(Conventional example) As a key switch used in various devices such as personal computers and word processors, the key top can be pressed with a soft touch.
Switches with rubber contacts placed inside the switch case are often used. FIG. 3 shows a conventional key switch of this kind, in which a cup-shaped rubber contact 33 made of an elastic material such as silicone rubber is attached to a switch base 32 housed in a switch case 31. When pressed, the conductive part 35 of the rubber contact 33 comes into contact with the contact parts 37, 37 on the wiring board 36 and conducts. When the pressure is released, the conductive part 35 rises due to the spring force of the coil spring 38, and the conductive part 35 contacts the contact parts 37, 37 on the wiring board 36. 37
I'm starting to move away from it. However, since the rubber contact 33 has a structure that is attached to the inside of the switch base 32, the switch base 32 requires attachment means such as a recess 39 for attachment, which not only complicates the structure at the end but also makes the rubber contact 33
The attachment force to the switch base 32 of No. 3 is weak and it easily falls off, and furthermore, the rubber contact 33
Due to the poor airtightness of the inside 30 of the key top 34
When pressed, the air inside 30 escapes and becomes a negative pressure state, and the shape of the rubber contact changes.
There were problems such as poor contact.

(Summary of the invention) The present invention was made in view of the above circumstances, and the purpose of the invention is to easily and firmly attach a cup-shaped rubber contact to the base of a switch.
Another object of the present invention is to provide a key switch that can be operated with a soft touch with good tactility.

To this end, the present invention forms a fitting part corresponding to the entire circumference of the switch base on the upper part of the rubber contact, and elastically fits the fitting part around the entire circumference of the switch base. The upper surface of the fitted fitting portion is pressed against the ceiling surface of the switch case by the spring force of a spring interposed between the key top and the switch case. By attaching the rubber contact to the switch base in this way, the rubber contact can be attached to the switch base easily and firmly, and the airtightness inside the rubber contact is ensured, and the air inside the rubber contact is kept under negative pressure. In addition, the elastic force of the rubber contact itself and its internal air pressure are used to resist the pressing force of the key top, preventing the rubber contact from buckling suddenly when the key top is operated, and pressing with a soft touch with good feel. It is made to be operable. Furthermore, when the pressure on the key top is released and the rubber contact rises, the fitting part hits the ceiling of the switch case and stops rising, so the fitting part acts as a cushioning material and prevents unpleasant collision sounds from occurring. In addition, the fitting part elastically contacts the ceiling surface to prevent unnecessary wobbling of the key top.

(Embodiments) Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a key switch 1 according to the present invention, where 2 is a key top and 3 is a switch case. Inside the switch case 3, a key top 2 is vertically disposed below the key top 2 via a connecting rod 5. A substantially disk-shaped switch base 4 is housed so as to be movable up and down by pressing the key top 2. Reference numeral 41 denotes a protruding edge portion protruding from the periphery of the switch base 4. Reference numeral 6 denotes a coil spring for springing the key top 2, which is interposed between the key top 2 and the switch case 3, and the key top 2 is springed upward by the spring force.

Reference numeral 7 denotes a cup-shaped rubber contact mounted below the switch base 4 (see also FIG. 2), which includes a cup-shaped main part 71 and an upper part of the main part 71 that is attached to the disc-shaped switch base 4. It consists of a fitting part 72 formed in a ring shape and having a substantially U-shaped cross section so as to correspond to the entire circumference, and a conductive part 73 is formed at the lower part of the main part 71. This rubber contact 7
is made of a soft elastic material such as silicone rubber. The outer diameter of the switch base 4 is slightly larger than the inner diameter of the fitting part 72, and the rubber contact 7 surrounds the entire circumference of the switch base 4 while forcibly expanding the fitting part 72 and is elastically fitted. In this state, the upper part of the fitting part 72 protrudes above the switch base 4. If the rubber contact 7 is fitted to the switch base 4 using its elasticity in this way, there is no need to specifically form a mounting part for the rubber contact 7 on the switch base 4, and the structure can be simplified accordingly. Rubber contact 7
It can be installed easily, firmly and airtightly.

Reference numeral 9 denotes a wiring board, and a contact portion 1 is provided on the upper surface of the wiring board.
0 and 10 are provided. Reference numeral 11 denotes an O-ring attached to the ground plane of the switch case 3 to the wiring board 9, which improves the grounding condition of the switch case 3 and prevents unnecessary gaps from forming between the switch case 3 and the wiring board 9 and dust. prevent intrusion.

The present key switch 1 has the above-mentioned configuration, and when the key top 2 is pressed against the spring force of the spring 6, the switch base 4 and the rubber contact 7 descend together with the key top 2, and the conductive part 73 of the rubber contact 7 becomes a contact point. It contacts the parts 10, 10 and becomes electrically conductive. When the pressed state is released, the key top 2 is lifted by the spring 6, the conductive part 73 is separated from the contact parts 10, and the upper surface of the fitting part 72 is in contact with the ceiling surface of the switch case 3. Then, key top 2 stops rising. In the above operation, the rubber contact 7 is attached with its fitting part 72 surrounding the entire circumference of the switch base 4 and being elastically fitted, so the airtightness inside the rubber contact 7 is extremely high, and the key top 2 Since the pressing force can be countered by the elastic force of the rubber contact 7 itself and the internal air pressure, the rubber contact 7 does not buckle suddenly due to the pressing force, and can be pressed with a soft touch with good feel.

Further, as mentioned above, since the upper part of the fitting part 72 protrudes above the switch base 7, the upper surface of the fitting part 72 made of an elastic material comes into contact with the ceiling surface of the switch case 3, and when the key top is operated. It is possible to prevent the occurrence of collision noise, and since there is a suitable sliding friction between the fitting part 72 and the ceiling surface of the switch case 3, there are advantages such as preventing the key top 2 from unnecessarily wobbling.

(Effects of the invention) As explained above, according to the invention, there is no need to specially form a mounting part for the rubber contact 7 on the switch base 4, and the rubber contact 7 can be easily attached by using its own elastic force. It can be installed firmly and securely, and since the inside of the rubber contact 7 is highly airtight, the pressing force of the key top 2 can be counteracted by the elastic force of the rubber contact 7 itself and the internal air pressure. The rubber contact 7 does not buckle suddenly and can be operated with a soft touch, and the cushioning action of the fitting part 72 that touches the ceiling of the switch case 3 prevents the generation of unpleasant collision sounds.
Unnecessary wobbling when the key top 2 is in the raised position can be prevented.

[Brief explanation of the drawing]

The figure shows an embodiment of the present invention.
This figure is a sectional view of a key switch, FIG. 2 is a partial perspective view, and FIG. 3 is a sectional view of a conventional key switch. 1...Key switch, 2...Key top, 3...
...Switch case, 4...Switch base, 6...
Spring, 7...Rubber contact, 72...Fitting part.

Claims (1)

[Scope of utility model registration request] A key top 2, a switch base 4 that moves up and down when the key top 2 is operated, a cup-shaped rubber contact 7 made of an elastic material, and a switch case 3 disposed on a wiring board 9 and housing the rubber contact 7. , a spring 6 interposed between the switch case 3 and the key top 2, and a fitting part 72 formed on the upper part of the rubber contact 7 to correspond to the entire circumference of the switch base 4;
The fitting portion 72 is elastically fitted to the switch base 4 by surrounding its entire circumference, and the upper surface of the fitted fitting portion 72 is pressed against the ceiling of the switch case 3 by the spring force of the spring 6. A key switch characterized by being pressed against a surface.