Dust venting contact with a non-circular hole

• US 4,412,113 A
• Filed: 08/04/1982
• Issued: 10/25/1983
• Est. Priority Date: 08/10/1979
• Status: Expired due to Term

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Oka, Shunzo, Nakagawa, Yoshinobu, Shiho, Kenichi, Mitsugi, Itaru
• Primary Examiner(s): Shepperd, John W.
• Assistant Examiner(s): Kidorf, Renee
• Application Number:
  US06/405,108
• Time in Patent Office: 447 Days
• Field of Search: 200/242, 200/241, 200/279, 200/159 B, 200/340, 200/67 DB
• US Class Current: 200/406
• CPC Class Codes: H01H 13/48 using buckling of disc springs
• CPC Class Codes: H01H 2227/026 Separate dome contact
• CPC Class Codes: H01H 2227/0261 with an aperture in contact making centre of dome

Abstract

In a push-on switch comprising a moving contact 6 of partial-hemisphere-face-shaped resilient metal diaphragm which is disposed with its periphery on a pair of peripheral fixed contacts 2b,2b in a contacting manner and at its central part apart above a central fixed contact 2a in an isolated manner at normal state,

the improvement is made such that the metal diaphragm moving contact 6 has an opening 6a having at least a protrusion 6b with respect to the opening 6a;

so that the opening 6a allows air to pass at inversing and restoring motions of the central principal part of the moving contact 6, thereby preventing drafting of dust onto the central fixed contact 2a, and that the protrusion 6b slides on and cleans the surface of the central fixed contact 2a at each pushing down of the central part of the moving contact 6.

Claims

1. A switch comprising:

a case having a recessed space therein;

a central fixed contact disposed at the center of the bottom face of said recessed space;

at least one peripheral fixed contact fixedly disposed at a peripheral part of the bottom face of said recessed shape;

a movable contact of resilient metal which is partially hemispherically shaped with a central portion movable between a normal state where said resilient metal is unflexed and no force is applied thereto and a strained state where said central portion is pushed down;

an actuation member having a pushing part movable in engagement with said central portion of said moving contact;

the improvement comprising said central portion of said moving contact having an opening, said opening having a peripheral edge at least a portion of which projects into said opening whereby said opening is non-circular.

2. A switch in accordance with claim 1 wherein said actuation member has a pushing part which is formed under said actuator and has at least an opening on the bottom face thereof.

3. The switch as claimed in claim 1 wherein said pushing part is in the form of an interrupted ring.

4. A switch in accordance with claim 1, wherein said opening is shaped into a cross having rounded ends.

5. A switch in accordance with claim 1, wherein inner diameter of said opening of said actuator is larger than said opening on said moving contact.