US3785393A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fluid power braking and steering system
Assignee: DBA SA
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Filing: 1972-05-02
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Granted: 1974-01-15
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Expires: 1992-05-02
Abstract
Abstract The vehicle hydraulic system comprises a pump, an accumulator adapted to energize a closed-centre power brake booster, and a open-centre power steering mechanism, the supply line of the power steering mechanism including a throttle in parallel relationship with a control valve. The valve member of the said control valve is actuated by a stepped piston responsive to the fluid pressures in the accumulator and in the supply line downstream said throttle, both pressures acting against a spring, thereby insuring a minimum level of pressure in the accumulator.
Inventors
- 👤 C Tanguy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 11:42
CPC Classifications
B; B62; B62D; B62D5/00; B62D5/06; B62D5/07; B60; B60T; B60T13/00; B60T13/10; B60T13/12; B60T13/14; B60T13/148; F; F15; F15B; F15B1/00; F15B1/02; F15B1/027; F15B11/00; F15B11/16; F15B2211/00; F15B2211/20; F15B2211/205; F15B2211/2053; F15B2211/20538; F15B2211/30; F15B2211/305; F15B2211/30505; F15B2211/31; F15B2211/3105; F15B2211/3111; F15B2211/3116; F15B2211/40; F15B2211/405; F15B2211/40507; F15B2211/40515; F15B2211/415; F15B2211/41509; F15B2211/42; F15B2211/428; F15B2211/45; F15B2211/70; F15B2211/78; F15B2211/781; Y; Y10; Y10T; Y10T137/00; Y10T137/2496; Y10T137/2559; Y10T137/2562; Y10T137/265; Y10T137/2663
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
235 words
In a hydraulic system including a fluid pressure source, a fluid accumulator pressurized by said source, and an open center receiver device operated by said source: a first throttle in the supply line communicating the pressure source with said open center receiver; a control valve in bypass relationship with said first throttle, said control valve including a body defining a stepped bore therewithin, stepped piston means slidably mounted in said bore and cooperating with the latter to define first and second chambers therewithin, a first inlet communicating one of the chambers to said supply line upstream of said first orifice, a second inlet communicating the other chamber with the accumulator, an outlet communicating said bore to said supply line downstream of said first throttle, passage means extending through said piston for communicating said first inlet with said outlet, normally closed valve elements in said bore controlling communication through said outlet, resilient means yieldably urging said piston to a position closing said valve elements, the pressure level in said chambers opposing said resilient means whereby the valve elements are opened when the sum of the corresponding pressure forces in said chambers reaches a predetermined value, said passage means including a cylindrical bore in said piston parallel to said stepped bore; and a projection secured to the body and extending into said stepped bore, one end of said cylindrical bore in said piston sealingly receiving said piston.
Claim 2
Dependent Claim
235 words
In a hydraulic system including a fluid pressure source, a fluid accumulator pressurized by said source, and an open center receiver device operated by said source: a first throttle in the supply line communicating the pressure source with said open center receiver; a control valve in bypass relationship with said first throttle, said control valve including a body defining a stepped bore therewithin, stepped piston means slidably mounted in said bore and cooperating with the latter to define first and second chambers therewithin, a first inlet communicating one of the chambers to said supply line upstream of said first orifice, a second inlet communicating the other chamber with the accumulator, an outlet communicating said bore to said supply line downstream of said first throttle, passage means extending through said piston for communicating said first inlet with said outlet, normally closed valve elements in said bore controlling communication through said outlet, resilient means yieldably urging said piston to a position closing said valve elements, the pressure level in said chambers opposing said resilient means whereby the valve elements are opened when the sum of the corresponding pressure forces in said chambers reaches a predetermined value, said passage means including a cylindrical bore in said piston parallel to said stepped bore; and a projection secured to the body and extending into said stepped bore, one end of said cylindrical bore in said piston sealingly receiving said piston.
Claim 3
Dependent Claim
177 words
In a hydraulic system including a fluid pressure source, a fluid accumulator pressurized by said source, and an open center receiver device operated by said source: a first throttle in the supply line communicating the pressure source with said open center receiver, a control valve in bypass relationship with said first throttle having an inlet and an outlet, said control valve including valve members controlling communication through the outlet, piston means for actuating said valve members, said piston means being responsive to the fluid pressure in the accumulator and the fluid pressure level upstream of the first throttle, resilient means opposing the fluid pressures acting on said piston means, whereby said resilient means urges said piston means to a position closing said valve elements when the sum of the fluid pressures acting on the piston means drops below a predetermined level, and a second throttle having a larger effective cross sectional area than that of the first throttle in the supply line communicating the outlet of the control valve and a port downstream of said first throttle.
Claim 4
Dependent Claim
177 words
In a hydraulic system including a fluid pressure source, a fluid accumulator pressurized by said source, and an open center receiver device operated by said source: a first throttle in the supply line communicating the pressure source with said open center receiver, a control valve in bypass relationship with said first throttle having an inlet and an outlet, said control valve including valve members controlling communication through the outlet, piston means for actuating said valve members, said piston means being responsive to the fluid pressure in the accumulator and the fluid pressure level upstream of the first throttle, resilient means opposing the fluid pressures acting on said piston means, whereby said resilient means urges said piston means to a position closing said valve elements when the sum of the fluid pressures acting on the piston means drops below a predetermined level, and a second throttle having a larger effective cross sectional area than that of the first throttle in the supply line communicating the outlet of the control valve and a port downstream of said first throttle.
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) | 1977-01-14 | 1977-07-16 | 1978-01-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-14 | 1981-07-16 | 1982-01-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-14 | 1985-07-16 | 1986-01-15 | $7700.00 | Window Closed / Lapsed |