US3651885A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydrostatic steering system for vehicles
Assignee: ZF Friedrichshafen AG
•
Filing: 1970-09-15
•
Granted: 1972-03-28
•
Expires: 1990-09-15
Abstract
Abstract The wheels of a vehicle are turned by fluid power operating devices when pressurized in response to directionally controlled shift of a control valve from a neutral position. The valve is shifted in opposite directions by manual rotation of a hand wheel and in a followup direction by a reversible motor through a selflocking reduction gear drive. Position sensing devices monitor followup movement of the motor and turning movement of the vehicle wheels to control energization of the motor in response to unbalance of a bridge circuit.
Inventors
- 👤 Armin Lang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 17:10
CPC Classifications
B; B62; B62D; B62D5/00; B62D5/06; B62D5/09
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
126 words
In a hydrostatic steering control system having a source of pressurized operating medium, at least one power operating device, a control valve through which the medium is supplied to the power operating device and manual actuating means operatively connected to the control valve, follow-up means for maintaining alignment between the manual actuating means and the power operating device, comprising a reversible motor, drive means operatively connecting the motor to the control valve for imparting follow-up movement thereto, a pair of sensing devices respectively driven by the power operating device and the drive means for monitoring movements thereof, and bridge circuit means connected to said sensing devices for controlLing operation of the motor in response to relative movement of said power operating device and the drive means.
Claim 2
Dependent Claim
126 words
In a hydrostatic steering control system having a source of pressurized operating medium, at least one power operating device, a control valve through which the medium is supplied to the power operating device and manual actuating means operatively connected to the control valve, follow-up means for maintaining alignment between the manual actuating means and the power operating device, comprising a reversible motor, drive means operatively connecting the motor to the control valve for imparting follow-up movement thereto, a pair of sensing devices respectively driven by the power operating device and the drive means for monitoring movements thereof, and bridge circuit means connected to said sensing devices for controlLing operation of the motor in response to relative movement of said power operating device and the drive means.
Claim 3
Dependent Claim
15 words
The system of claim 1, wherein said drive means includes a self-locking, reduction drive assembly.
Claim 4
Dependent Claim
44 words
The system of claim 2, wherein said power operating device is connected by the control valve to the source in a closed fluid circuit, said valve being shiftable from a neutral recirculating flow position to flow blocking positions causing pressurization of the operating device.
Claim 5
Dependent Claim
18 words
The system of claim 3, including torsionally yieldable means coupling the manual actuating means and the drive means.
Claim 6
Dependent Claim
18 words
The system of claim 2, including torsionally yieldable means coupling the manual actuating means and the drive means.
Claim 7
Dependent Claim
18 words
The system of claim 1, including torsionally yieldable means coupling the manual actuating means and the drive means.
Claim 8
Dependent Claim
44 words
The system of claim 6, wherein said power operating device is connected by the control valve to the source in a closed fluid circuit, said valve being shiftable from a neutral recirculating flow position to flow blocking positions causing pressurization of the operating device.
References Cited (Backward Citations)
US2962108A
Cited
US3011579A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-03-28 | 1975-09-27 | 1976-03-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-03-28 | 1979-09-27 | 1980-03-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-03-28 | 1983-09-27 | 1984-03-28 | $7700.00 | Window Closed / Lapsed |