Patent US4859820A successfully refreshed from Google Patents.
US4859820A
Expired / Lapsed
US
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Quiet key switch
Assignee: AT&T Inc
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Filing: 1988-03-31
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Granted: 1989-08-22
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Expires: 2008-03-31
Abstract
Abstract A key switch utilizing a buckling compression spring to move a switch actuator mechanism includes a cylindrical core of resilient material located within an opening formed by the coils of the compression spring to attenuate the acoustical energy generated by the buckling and unbuckling action of the spring.
Inventors
- 👤 Casimer Gotfryd
- 👤 Stephen L. Kay
- 👤 Hartland P. Klotz
- 👤 Robert M. Wentzel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 16:37
CPC Classifications
H; H01; H01H; H01H13/00; H01H13/70; H01H13/702; H01H13/705; H01H2221/00; H01H2221/062; H01H2235/00; H01H2235/012
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
125 words
In a key switch acutating mechanism comprising: a key top; a housing having means for slidably receiving said key top for vertical motion thereof; a pivoting rocker means located in said housing opposite said key top; a buckling compression spring including coils forming a cylindrical opening, said spring mounted between said key top and said pivoting rocker means, the spring buckling and unbuckling in response to the downward and upward motion of the key top, respectively, the spring generating acoustical energy by the buckling and unbuckling action of the spring which energy manifests itself in at least two distinct types of sounds--metallic click and metallic ringing; and means for damping acoustical energy generated by the spring which manifests itself by the sound of metallic ringing.
Claim 2
Dependent Claim
125 words
In a key switch acutating mechanism comprising: a key top; a housing having means for slidably receiving said key top for vertical motion thereof; a pivoting rocker means located in said housing opposite said key top; a buckling compression spring including coils forming a cylindrical opening, said spring mounted between said key top and said pivoting rocker means, the spring buckling and unbuckling in response to the downward and upward motion of the key top, respectively, the spring generating acoustical energy by the buckling and unbuckling action of the spring which energy manifests itself in at least two distinct types of sounds--metallic click and metallic ringing; and means for damping acoustical energy generated by the spring which manifests itself by the sound of metallic ringing.
Claim 3
Dependent Claim
29 words
Apparatus as described in claim 1 wherein said damping means comprises a cylindrical core of resilient material positioned within the opening formed by the coils of the buckling spring.
Claim 4
Dependent Claim
19 words
Apparatus as described in claim 2 wherein said cylindrical core is made of a closed cell urethane foam material.
Claim 5
Dependent Claim
28 words
Apparatus as described in claim 3 wherein the diameter of said cylindrical core is larger than the diameter of the opening formed by the coils of the spring.
Claim 6
Dependent Claim
19 words
Apparatus as described in claim 4 wherein the length of said cylindrical core is substantially equal to its diameter.
Claim 7
Dependent Claim
20 words
Apparatus as described in claim 5 wherein one end of said cylindrical core is positioned near said pivoting rocker means.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-08-21 | 1993-02-20 | 1993-08-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-08-21 | 1997-02-20 | 1997-08-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-08-21 | 2001-02-20 | 2001-08-22 | $7700.00 | Window Closed / Lapsed |