Patent US4526342A successfully refreshed from Google Patents.
US4526342A
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US
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Actuator device for a hydraulic spool valve
Assignee: Smiths Technologies Ltd
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Filing: 1982-12-22
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Granted: 1985-07-02
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Expires: 2002-12-22
Abstract
Abstract There is disclosed an actuation device for operating a hydraulic spool valve. The device includes a d.c. electric motor and a high-ratio gearbox. The output of the gearbox connects with the spool of the valve through a segmented rack and pitman pin or a rack and pinion arrangement. A control circuit for the electric motor includes position feed-back to permit accurate positioning of the spool. Further, spring means are included to bias the spool to its neutral position in the absence of a control signal or on occurrence of a fail condition.
Inventors
- 👤 Donald C. Wakefield, deceased
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 10:21
CPC Classifications
F; F15; F15B; F15B13/00; F15B13/02; F15B13/04; F15B13/044; F15B13/0442; F15B13/0444; F15B13/0401; F15B2013/0412; Y; Y10; Y10T; Y10T137/00; Y10T137/8593; Y10T137/86493; Y10T137/86574; Y10T137/86622
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
111 words
A hydraulic spool valve assembly comprising: a hydraulic spool valve and an actuation device for a spool valve; said actuation device including: an electric motor; control means for actuating said motor; a gear box having an input gear wheel driven by said motor and output means connected to the spool of said valve; wherein said output means comprises a segmented rack and pitman pin, the segmented rack being driven by said input gear wheel and the pitman pin being connected directly to the rack and to the spool valve and connected directly to the spool valve such that rotation of the input gear wheel effects linear movement of the spool valve.
Claim 2
Dependent Claim
111 words
A hydraulic spool valve assembly comprising: a hydraulic spool valve and an actuation device for a spool valve; said actuation device including: an electric motor; control means for actuating said motor; a gear box having an input gear wheel driven by said motor and output means connected to the spool of said valve; wherein said output means comprises a segmented rack and pitman pin, the segmented rack being driven by said input gear wheel and the pitman pin being connected directly to the rack and to the spool valve and connected directly to the spool valve such that rotation of the input gear wheel effects linear movement of the spool valve.
Claim 3
Dependent Claim
15 words
An assembly as claimed in claim 1 wherein the motor is a d.c. electric motor.
Claim 4
Dependent Claim
16 words
An assembly as claimed in claim 1 wherein said control means includes a position feedback loop.
Claim 5
Dependent Claim
18 words
An assembly as claimed in claim 1 and including means for returning the spool to its neutral position.
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) | 1988-07-01 | 1988-12-31 | 1989-07-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-07-01 | 1992-12-31 | 1993-07-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-07-01 | 1996-12-31 | 1997-07-02 | $7700.00 | Window Closed / Lapsed |