US3832849A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Servo steering device, especially for automobiles
Assignee: ZF Friedrichshafen AG
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Filing: 1973-07-05
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Granted: 1974-09-03
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Expires: 1993-07-05
Abstract
Abstract A hydrostatic servo operated steering system having primary and shunt motors connected to the steering linkage under control of steering wheel and pressure operated valves to effect a change in steering effort in order to meet changes in load or resistance. A shuttle valve responsive to a pressure differential between the output of the engine driven servo pump and the pressure applied to the primary servo motor, controls supply of operating pressure medium to the shunt motor from either the servo motor or the steering wheel actuated control pump in the event the servo pump fails.
Inventors
- 👤 A Lang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 12:38
CPC Classifications
B; B62; B62D; B62D5/00; B62D5/06; B62D5/09; B62D5/093
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
172 words
In a hydrostatic servo steering system including an engine driven servo pump 2 supplying an operating pressure medium through a control valve 4 and a metering control pump 3 to a servo motor 5 and a shunt motor 7 to which said pressure medium is supplied through a shunt valve 6 having control ports 24 and 25 through which pressure medium from the control valve is conducted, means for supplying said pressure medium to the shunt motor from the control pump in the event the servo pump fails, comprising a pressure supply conduit 8 connecting the servo pump to the shunt valve, passage means 9 interconnecting the supply conduit with the control valve for conducting the pressure medium to the servo motor, and shuttle valve means 28 connected to the control ports of the shunt valve and responsive to a pressure differential between said supply conduit and the control ports for conducting the pressure medium to the shunt valve from either the supply conduit or the control pump through the control valve.
Claim 2
Dependent Claim
172 words
In a hydrostatic servo steering system including an engine driven servo pump 2 supplying an operating pressure medium through a control valve 4 and a metering control pump 3 to a servo motor 5 and a shunt motor 7 to which said pressure medium is supplied through a shunt valve 6 having control ports 24 and 25 through which pressure medium from the control valve is conducted, means for supplying said pressure medium to the shunt motor from the control pump in the event the servo pump fails, comprising a pressure supply conduit 8 connecting the servo pump to the shunt valve, passage means 9 interconnecting the supply conduit with the control valve for conducting the pressure medium to the servo motor, and shuttle valve means 28 connected to the control ports of the shunt valve and responsive to a pressure differential between said supply conduit and the control ports for conducting the pressure medium to the shunt valve from either the supply conduit or the control pump through the control valve.
Claim 3
Dependent Claim
47 words
The combination of claim 1 including a spring biased check valve 30 in the passage means for reducing the pressure of the medium supplied to the shuttle valve means from the control port relative to the pressure in the supply conduit while the servo pump is operating.
Claim 4
Dependent Claim
26 words
The combination of claim 1 wherein said shuttle valve means 128 includes a spring 131 opposing the pressure of the medium supplied from the control port.
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) | 1977-09-02 | 1978-03-04 | 1978-09-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-02 | 1982-03-04 | 1982-09-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-02 | 1986-03-04 | 1986-09-03 | $7700.00 | Window Closed / Lapsed |