Cover Member For Push-Button Switch And Method Of Manufacturing The Same

• US 20070199814A1
• Filed: 03/15/2005
• Published: 08/30/2007
• Est. Priority Date: 03/25/2004
• Status: Active Grant

• Current Assignee: Shin-Etsu Polymer Company Limited (Shin-Etsu Chemical Company Limited)
• Original Assignee: Shin-Etsu Polymer Company Limited (Shin-Etsu Chemical Company Limited)
• Inventors: Watanabe, Kimihiko, Kobayashi, Takato, Nozaki, Tomohiro
• Granted Patent: US 7,525,061 B2
• Time in Patent Office: Days
• US Class Current: 200/520
• CPC Class Codes: B29C 45/14 incorporating preformed parts or layers, e.g. injection moulding around inserts or for coating articles B29C45/1671 takes precedence
• CPC Class Codes: B29L 2031/466 Keypads, keytops
• CPC Class Codes: H01H 13/86 characterised by the casing, e.g. sealed casings or casings reducible in size
• CPC Class Codes: H01H 2209/012 avoiding too large deformation or stress
• CPC Class Codes: H01H 2209/074 elastomeric
• CPC Class Codes: H01H 2219/062 Light conductor
• CPC Class Codes: H01H 2221/002 integral with membrane
• CPC Class Codes: H01H 2221/05 Force concentrator; Actuating dimple
• CPC Class Codes: H01H 2229/044 Injection moulding
• CPC Class Codes: H01H 2231/022 Telephone handset
• CPC Class Codes: H01H 2233/004 One molded part

Abstract

Influence of an impact on a hard base or deformation of the hard base is alleviated on a circuit board.

A push-button switch cover member has a hard base 1 and a keypad 2, the hard base 1 is made of a hard resin with a through hole 4 for a key top, and the keypad 2 is made of a silicone rubber film. The keypad 2 thinly covers the entire back surface of the hard base 1 and is exposed through an internal periphery of the through hole 4 of the hard base 1 to the front surface side of the hard base 1. The back side of the keypad 2 located in an inside region of the through hole 4 is provided with a press projection 6a for press of a contact part.

Claims

1. A cover member for a push-button switch comprising a hard base and a keypad, wherein the hard base is made of a hard resin with a through hole for a key top, and

wherein the keypad is made of a silicone rubber film, a front surface of the keypad is in contact with an entire back surface of the hard base, the keypad is exposed through the through hole, and a back surface of the keypad corresponding to the through hole is provided with a press projection for pressing a contact point.

2. The cover member for the push-button switch according to claim 1, wherein a portion of the keypad exposed through the through hole of the hard base forms the key top.

3. The cover member for the push-button switch according to claim 1, wherein the front surface of the keypad exposed through the through hole of the hard base is provided with the key top made of a hard resin.

4. The cover member for the push-button switch according to claim 1, wherein the hard base is made of a polycarbonate resin, and

wherein the silicone rubber film is made of a selectively adhesive silicone rubber containing an additive of an auxiliary agent to be chemically bonded to the polycarbonate resin.

5. The cover member for the push-button switch according to claim 1, wherein a groove is formed between said through holes adjacent to each other on the back side of the hard base.

6. The cover member for the push-button switch according to claim 1, wherein the hard base is made of an optically transparent resin.

7. A method of producing the cover member for the push-button switch as defined in claim 1, the method comprising the steps of:

inserting the hard base preliminarily shaped and decorated, in a mold; and

thereafter filling the mold with a silicone rubber containing a component highly adhesive to the hard base, and heating and curing the silicone rubber, thereby integrating the hard base and the keypad.

8. A method of producing the cover member for the push-button switch as defined in claim 3, the method comprising the steps of:

inserting the hard base preliminarily shaped and decorated, in a mold;

thereafter filling the mold with a silicone rubber containing a component highly adhesive to the hard base, and heating and curing the silicone rubber, thereby integrating the hard base and the keypad; and

thereafter bonding and fixing the key top to the front surface of the keypad exposed through the through hole of the hard base.

9. The production method of the cover member for the push-button switch according to claim 7, wherein the hard base is made of a polycarbonate resin, and

wherein the silicone rubber film is made of a selectively adhesive silicone rubber containing an additive of an auxiliary agent to be chemically bonded to the polycarbonate resin.

10. The production method of the cover member for the push-button switch according to claim 9, wherein a heating temperature in the heating step is not less than a temperature necessary for curing the selectively adhesive silicone rubber and not more than a deflection temperature under load of the hard base.

11. The production method of the cover member for the push-button switch according to claim 7, wherein the mold in which the hard base is inserted, is a movable mold opposed to a fixed mold having a gate for injection of a material, and

wherein after the step of integrating the hard base and the keypad, the movable mold is moved, and the integrated hard base and keypad attached to the movable mold are detached therefrom.