Structure of key switch

• US 5,283,408 A
• Filed: 08/04/1992
• Issued: 02/01/1994
• Est. Priority Date: 08/04/1992
• Status: Expired due to Term

• Current Assignee: Lite-On Technology Corporation
• Original Assignee: Silitek Corporation (Lite-On Technology Corporation)
• Inventors: Chen, S. H.
• Primary Examiner(s): Recla, Henry J.
• Assistant Examiner(s): BARRETT, GLENN
• Application Number:
  US07/924,710
• Time in Patent Office: 546 Days
• Field of Search: 200/341, 200/342, 200/343, 200/344, 200/345, 200/329, 200/520, 200/521, 200/530, 200/534, 200/517, 200/513, 4/255.11, 4/255.12
• US Class Current: 200/345
• CPC Class Codes: H01H 13/14 Operating parts, e.g. push-button
• CPC Class Codes: H01H 13/70 having a plurality of operating members associated with different sets of contacts, e.g. keyboard mounting together a plurality of independent switches H02B
• CPC Class Codes: H01H 2213/002 with external pressure
• CPC Class Codes: H01H 2215/004 Collapsible dome or bubble
• CPC Class Codes: H01H 2215/012 Positioning of individual dome
• CPC Class Codes: H01H 2221/026 Guiding or lubricating nylon
• CPC Class Codes: H01H 2233/036 with limited freedom

Abstract

A key switch includes a rectangular key cap having a unitary, hollow, rectangular plunger inserted into a rectangular hole on a key base and pressed to squeeze a rubber tone causing a conductor to electrically connect a contact on the printed circuit board of a keyboard, wherein the rectangular plunger has four circular rails on the four corners thereof along its length respectively inserted in four circular grooves on the rectangular guide slot of the key base for stable movement, and two smoothly curved, hooked spring plates releasably hooked with two opposite hooked portions on the key base for positioning.

Claims

1. A keyboard key switch comprising:

a rectangular key cap having an integral, downwardly directed, hollow, rectangular plunger on an inside thereof, said rectangular plunger having four segmented circular rails extending along four respective corners thereof, two fixed, flat wall side walls form two opposite sides of said plunger, and another two opposite sides thereof having two spring plates thereon, each of said spring plates being biased outwardly and terminating in an outwardly opening hook;

a key base adapted to be fastened on a frame of a keyboard, said key base having a rectangular guide slot on a top thereof, said rectangular plunger being received in said slot, a conical horn gate extending downwardly and outwardly from said rectangular guide slot, two hooked slots being formed at opposite locations within said rectangular guide slot in said conical horn gate for releasably receiving the hook on the respective spring plates, and a bottom ring extending downwardly from said conical horn gate, said rectangular guide slot having circular grooves along four corners thereof on an inside into which the four circular segment rails of said rectangular plunger ride; and

a compressible rubber tone received in the conical horn gate inside said key base, having a top portion abutting a bottom portion of said rectangular plunger, a conductor located on an inside thereof adapted to contact a contact on a printed circuit board of said keyboard when said key cap is depressed, and a plurality of air vents being formed through a bottom portion thereof.

2. The key switch according to claim 1, wherein said spring plates each have a smoothly curved outside surface adapted to ride along the respective hooked slot on said key base when said cap is depressed.