US3579984A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fluid power steering system with fluid pressure reserve
Assignee: Motors Liquidation Co
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Filing: 1969-06-04
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Granted: 1971-05-25
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Expires: 1989-06-04
Abstract
Abstract A reserve supply of fluid pressure is provided for a vehicle fluid power steering system including an accumulator kept charged to a predetermined minimum pressure and communicated to the fluid power steering gear in parallel with the normal or primary pump source of pressure fluid. The rotary control valve for the fluid power gear includes a primary set of open center configuration lands and grooves operable over a normal steering travel range in the valve to selectively pressurize either side of the fluid motor, and a further set of closed center configuration lands and grooves communicated to the accumulator fluid pressure but normally blocking communication between the accumulator and the fluid motor until normal steering travel is exceeded in either direction of actuation, as during failure of the primary pump.
Inventors
- 👤 Robert P Rohde
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 20:38
CPC Classifications
B; B62; B62D; B62D5/00; B62D5/06; B62D5/30
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
297 words
In a vehicle power steering system, a double-acting fluid motor, a primary source of pressure fluid, a secondary source of pressure fluid, a reservoir, and a control valve including a pair of relatively movable valve members, one of said valve members having alternate lands and grooves and the other of said valve members having complementary alternate grooves and lands juxtaposed to said first mentioned land and grooves and defining therewith an open center pressure port communicated with said primary source, a pair of motor ports flanking said pressure port and each communicated with a respective end chamber of said fluid motor, and a return port adjacent each said motor port and communicated with said reservoir, said valve members being relatively movable in opposite directions from an open center neutral relation and over a normal steering valve travel range for selective pressurization of one of said motor end chambers to varying degrees, said valve members having further juxtaposed lands and grooves defining adjacent each said return port a further motor port communicated to a respective one of the motor end chambers and secondary pressure ports communicated with said secondary source of pressure fluid, and further juxtaposed lands and grooves of said valve members cooperating to block communication between said secondary pressure source and said further motor ports during said movement of said valve members in either direction over said normal travel range thereof, further relative movement of said valve members in either direction beyond said normal travel range thereof connecting one of said secondary pressure ports with a further motor port respective to the selected direction of movement to communicate said secondary pressure source with said motor whereby in the absence of pressure fluid from said primary source said secondary pressure source serves to selectively operate said motor.
Claim 2
Dependent Claim
297 words
In a vehicle power steering system, a double-acting fluid motor, a primary source of pressure fluid, a secondary source of pressure fluid, a reservoir, and a control valve including a pair of relatively movable valve members, one of said valve members having alternate lands and grooves and the other of said valve members having complementary alternate grooves and lands juxtaposed to said first mentioned land and grooves and defining therewith an open center pressure port communicated with said primary source, a pair of motor ports flanking said pressure port and each communicated with a respective end chamber of said fluid motor, and a return port adjacent each said motor port and communicated with said reservoir, said valve members being relatively movable in opposite directions from an open center neutral relation and over a normal steering valve travel range for selective pressurization of one of said motor end chambers to varying degrees, said valve members having further juxtaposed lands and grooves defining adjacent each said return port a further motor port communicated to a respective one of the motor end chambers and secondary pressure ports communicated with said secondary source of pressure fluid, and further juxtaposed lands and grooves of said valve members cooperating to block communication between said secondary pressure source and said further motor ports during said movement of said valve members in either direction over said normal travel range thereof, further relative movement of said valve members in either direction beyond said normal travel range thereof connecting one of said secondary pressure ports with a further motor port respective to the selected direction of movement to communicate said secondary pressure source with said motor whereby in the absence of pressure fluid from said primary source said secondary pressure source serves to selectively operate said motor.
Claim 3
Dependent Claim
343 words
In a vehicle power steering system, a double-acting fluid motor, a pump providing a primary source of pressure fluid, an accumulator source of secondary pressure fluid, a reservoir, means connection said pump and said accumulator for maintaining the latter at a predetermined level of fluid pressure, and a control valve including a pair of relatively rotatable valve members, one of said valve members having angularly spaced alternate lands and grooves and the other of said valve members having complementary angularly spaced alternate grooves and lands juxtaposed to said first mentioned land and grooves and defining therewith an open center pressure port communicated with said pump, a pair of motor ports flanking said pressure port and each communicated with a respective end chamber of said fluid motor, and a return port adjacent each said motor port and communicated with said reservoir, said valve members being relatively angularly movable in opposite directions from an open center neutral relation and over a normal steering valve travel range for selective pressurization of one of said motor end chambers to varying degrees, said one valve member having further angularly spaced alternate lands and grooves and said other valve member having further angularly spaced alternate grooves and lands juxtaposed to the further lands and grooves of said one member and defining adjacent each said return port a further motor port each communicated to a respective one of the motor end chambers and secondary pressure ports communicated with said accumulator, said further juxtaposed lands and grooves of said valve members cooperating to block communication between said accumulator an said further motor ports during said angular movement of said valve members in either direction over said normal travel range thereof, further relative angular movement of said valve members in either direction beyond said normal travel range thereof connecting one of said secondary pressure ports with a further motor port respective to the selected direction of movement to communicate said accumulator with said motor whereby in the absence of pressure fluid from said pump said accumulator serves to selectively operate said motor.
Claim 4
Dependent Claim
343 words
In a vehicle power steering system, a double-acting fluid motor, a pump providing a primary source of pressure fluid, an accumulator source of secondary pressure fluid, a reservoir, means connection said pump and said accumulator for maintaining the latter at a predetermined level of fluid pressure, and a control valve including a pair of relatively rotatable valve members, one of said valve members having angularly spaced alternate lands and grooves and the other of said valve members having complementary angularly spaced alternate grooves and lands juxtaposed to said first mentioned land and grooves and defining therewith an open center pressure port communicated with said pump, a pair of motor ports flanking said pressure port and each communicated with a respective end chamber of said fluid motor, and a return port adjacent each said motor port and communicated with said reservoir, said valve members being relatively angularly movable in opposite directions from an open center neutral relation and over a normal steering valve travel range for selective pressurization of one of said motor end chambers to varying degrees, said one valve member having further angularly spaced alternate lands and grooves and said other valve member having further angularly spaced alternate grooves and lands juxtaposed to the further lands and grooves of said one member and defining adjacent each said return port a further motor port each communicated to a respective one of the motor end chambers and secondary pressure ports communicated with said accumulator, said further juxtaposed lands and grooves of said valve members cooperating to block communication between said accumulator an said further motor ports during said angular movement of said valve members in either direction over said normal travel range thereof, further relative angular movement of said valve members in either direction beyond said normal travel range thereof connecting one of said secondary pressure ports with a further motor port respective to the selected direction of movement to communicate said accumulator with said motor whereby in the absence of pressure fluid from said pump said accumulator serves to selectively operate said motor.
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) | 1974-05-24 | 1974-11-23 | 1975-05-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-24 | 1978-11-23 | 1979-05-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-24 | 1982-11-23 | 1983-05-25 | $7700.00 | Window Closed / Lapsed |