US3554089A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Servosteering system
Assignee: ZF Friedrichshafen AG
•
Filing: 1969-04-07
•
Granted: 1971-01-12
•
Expires: 1989-04-07
Abstract
Abstract A dual cylinder hydraulic steering booster system is disclosed which has one primary servomotor normally operable, but which system also has a secondary servomotor automatically pressurized to supplement the power of the primary servomotor in response to an increase in steering required effort. A single servopump output feeds both servomotors; thus if only the primary servomotor is operating, the steering rate is rapid, but the rate is decreased when the secondary servomotor is pressurized should increased steering resistance be met; the booster force of both servomotors then being utilized.
Inventors
- 👤 Armin Lang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 22:06
CPC Classifications
B; B62; B62D; B62D5/00; B62D5/06; B62D5/09; B62D5/093
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
171 words
A hydraulic steering booster system comprising: a primary control valve and a primary servomotor connected thereto to be pressurized therethrough; a secondary control valve connected to said primary servomotor and actuatable in response to a predetermined pressure therein; a secondary servomotor connected to said secondary control valve to be pressurized therethrough in response to said predetermined pressure; including a source of pressure fluid communicating with and controllable through said primary valve by an operator to pressurize said primary servomotor and communicating with said secondary valve for pressurizing therethrough said secondary servomotor; whereby at steering resistance loads below that which effect said predetermined pressure in said primary servomotor said source feeds only to said primary servomotor for actuation at a relatively rapid rate and at low pressure, but wherein said predetermined pressure is reached upon an increase in steering resistance to actuate said secondary valve so that said source then feeds to said secondary servomotor also, said servomotors then being actuated simultaneously at a relatively slower rate and at a higher pressure.
Claim 2
Dependent Claim
171 words
A hydraulic steering booster system comprising: a primary control valve and a primary servomotor connected thereto to be pressurized therethrough; a secondary control valve connected to said primary servomotor and actuatable in response to a predetermined pressure therein; a secondary servomotor connected to said secondary control valve to be pressurized therethrough in response to said predetermined pressure; including a source of pressure fluid communicating with and controllable through said primary valve by an operator to pressurize said primary servomotor and communicating with said secondary valve for pressurizing therethrough said secondary servomotor; whereby at steering resistance loads below that which effect said predetermined pressure in said primary servomotor said source feeds only to said primary servomotor for actuation at a relatively rapid rate and at low pressure, but wherein said predetermined pressure is reached upon an increase in steering resistance to actuate said secondary valve so that said source then feeds to said secondary servomotor also, said servomotors then being actuated simultaneously at a relatively slower rate and at a higher pressure.
Claim 3
Dependent Claim
23 words
A hydraulic steering booster system as set forth in claim 1, each of said servomotors being double ended and having mechanically connected pistons.
Claim 4
Dependent Claim
69 words
A hydraulic steering booster system as set forth in claim 1, said secondary control valve being a multiway valve and comprising a reciprocal valve spool, a housing for said spool effecting pressure chambers at respective ends thereof; said pressure chambers communicating with respective ends of said primary servomotor, including means biasing said spool to a neutral position whereat pressure fluid thereto is blocked from communicating with respective housing grooves.
Claim 5
Dependent Claim
62 words
A hydraulic booster steering system as set forth in claim 3, said spool having three grooves in symmetrical array and said housing having coacting grooves for flow thereinto upon actuation of said spool; said souRce of pressure fluid communicating with the center groove of said spool and said secondary servomotor being double ended and the ends thereof communicating with respective housing grooves.
Claim 6
Dependent Claim
97 words
A hydraulic steering booster system as set forth in claim 1, said secondary control valve comprising a reciprocal valve spool and means therefore effecting chambers for pressure communication to the ends of said spool from said primary servomotor, said chambers having pressure actuatable pistons exposed to said primary servomotor pressure and disposed to abut respective ends of said spool for reciprocation thereof and having a cross sectional area less than that of said spool; including means for biasing said spool against pressure actuation in either direction until a predetermined pressure becomes operative on either of said pistons.
Claim 7
Dependent Claim
57 words
A hydraulic steering booster system as set forth in claim 1, said primary control valve and primary servomotor having hydraulic circuitry comprising a flow regulating valve connected intermediate said source of pressure fluid and said primary control valve wherein said source of pressure fluid communicates from a point upstream of said latter valve to said secondary control
Claim 8
Dependent Claim
111 words
As supplemental power arrangement for a hydraulic steering booster system installation having a source of pressure fluid and wherein said installation comprises an arrangement having a steering spindle operated multiway valve and a servomotor controlled thereby and mechanically connected to operate a steering mechanism; said supplemental power arrangement comprising a pressure operable multiway valve and means for connection thereof with the source of pressure fluid and having means operative to actuate said latter valve responsive to a predetermined pressure in said servomotor; and another servomotor communicating with said latter multiway valve for pressurizing control thereby responsive to actuation of said latter valve; and connection means between the pistons of said servomotors.
Claim 9
Dependent Claim
111 words
As supplemental power arrangement for a hydraulic steering booster system installation having a source of pressure fluid and wherein said installation comprises an arrangement having a steering spindle operated multiway valve and a servomotor controlled thereby and mechanically connected to operate a steering mechanism; said supplemental power arrangement comprising a pressure operable multiway valve and means for connection thereof with the source of pressure fluid and having means operative to actuate said latter valve responsive to a predetermined pressure in said servomotor; and another servomotor communicating with said latter multiway valve for pressurizing control thereby responsive to actuation of said latter valve; and connection means between the pistons of said servomotors.
Claim 10
Dependent Claim
123 words
A supplemental booster steering unit for attachment to an existing booster servomotor steering system and comprising a multiway valve and means for connecting said valve to the source of fluid pressure which feeds said existing system; a servomotor having connections to said multiway valve to be pressurized therethrough upon actuation thereof; means for biasing said multiway valve to a neutral position comprising springs requiring a predetermined force to effect flexure thereof and means providing pressure chambers for said multiway valve communicating with the servomotor of said existing system whereby said multiway valve is actuated upon predetermined pressure in said latter servomotor to effect operation of the servomotor controlled thereby, and means to connect the piston thereof to the piston of said existing system.
Claim 11
Dependent Claim
123 words
A supplemental booster steering unit for attachment to an existing booster servomotor steering system and comprising a multiway valve and means for connecting said valve to the source of fluid pressure which feeds said existing system; a servomotor having connections to said multiway valve to be pressurized therethrough upon actuation thereof; means for biasing said multiway valve to a neutral position comprising springs requiring a predetermined force to effect flexure thereof and means providing pressure chambers for said multiway valve communicating with the servomotor of said existing system whereby said multiway valve is actuated upon predetermined pressure in said latter servomotor to effect operation of the servomotor controlled thereby, and means to connect the piston thereof to the piston of said existing system.
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) | 1974-01-11 | 1974-07-13 | 1975-01-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-01-11 | 1978-07-13 | 1979-01-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-01-11 | 1982-07-13 | 1983-01-12 | $7700.00 | Window Closed / Lapsed |