Patent US3645296A successfully refreshed from Google Patents.
US3645296A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Power-assisted steering and like systems
Assignee: TRW Steering Systems Ltd
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Filing: 1969-10-31
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Granted: 1972-02-29
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Expires: 1989-10-31
Abstract
Abstract A power-assisting rack and pinion steering system including a housing, relatively rotatable torque input and output shafts mounted for rotation in the housing, a pinion mounted for joint rotation on the torque output shaft, a rack engaging the pinion and a fluid valve assembly for controlling the flow of fluid to and from the opposite ends of a double-acting servomotor also connected to the rack for assisting in the movement thereof. The valve assembly comprises a circumferentially grooved spool valve connected to one of said shafts for axial movement, such movement occurring when the shafts are rotated relative to one another. Axial movement of the spool valve establishes fluid communication between a power fluid pump and the servomotor for powered movement of the servomotor and hence the rack.
Inventors
- 👤 Frederick John Adams
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 22:32
CPC Classifications
B; B62; B62D; B62D5/00; B62D5/06; B62D5/08; B62D5/087; Y; Y10; Y10T; Y10T137/00; Y10T137/8593; Y10T137/86493; Y10T137/86574; Y10T137/8667; Y10T137/86694; Y10T137/8671
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
185 words
A power-assisted steering unit comprising a housing including means forming a fluid inlet and a fluid outlet, input shaft means and output shaft means mounted on said housing for relative rotation on aligned axes, spool valve means rotatably carried in said housing and shiftable axially for controlling the flow of fluid between said fluid inlet and outlet, said spool valve means being disposed coaxially with and in surrounding relation to said input shaft means, first and second follower grooves formed respectively on said input shaft means and said output shaft means, said first follower groove being arranged axially with respect to the axes of said shaft means and said second follower groove being arranged helically with respect to the axes of said shaft means, cam follower means operatively engaging said first and second follower grooves and movable axially in response to relative rotation of said input means and said output shaft means and means connecting said cam follower means and said spool valve means for joint movement whereby said spool valve means rotates jointly with and shifts axially with respect to said input shaft means.
Claim 2
Dependent Claim
185 words
A power-assisted steering unit comprising a housing including means forming a fluid inlet and a fluid outlet, input shaft means and output shaft means mounted on said housing for relative rotation on aligned axes, spool valve means rotatably carried in said housing and shiftable axially for controlling the flow of fluid between said fluid inlet and outlet, said spool valve means being disposed coaxially with and in surrounding relation to said input shaft means, first and second follower grooves formed respectively on said input shaft means and said output shaft means, said first follower groove being arranged axially with respect to the axes of said shaft means and said second follower groove being arranged helically with respect to the axes of said shaft means, cam follower means operatively engaging said first and second follower grooves and movable axially in response to relative rotation of said input means and said output shaft means and means connecting said cam follower means and said spool valve means for joint movement whereby said spool valve means rotates jointly with and shifts axially with respect to said input shaft means.
Claim 3
Dependent Claim
47 words
The invention as defined in claim 1 in which said first follower groove is disposed radially outwardly of and in axially overlapping relation with said second follower groove, and said cam follower means extends radially inwardly through said first follower groove and into said second follower groove.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-02-28 | 1975-08-30 | 1976-02-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-02-28 | 1979-08-30 | 1980-02-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-02-28 | 1983-08-30 | 1984-02-29 | $7700.00 | Window Closed / Lapsed |