US3752248A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydraulic steering system
Assignee: Doosan Bobcat North America Inc
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Filing: 1971-08-31
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Granted: 1973-08-14
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Expires: 1991-08-31
Abstract
Abstract A hydraulic steering system for vehicular equipment, such as lift trucks, earth moving equipment, and the like, having two steerable wheels, an axle bed for the wheels and a linkage interconnecting the wheels, in which the steerable wheels are operated by power cylinders connected to the axle bed and to the linkage, and a valve controls a fluid under relatively high pressure for operating the two cylinders. A pilot cylinder normally operating under a relatively low pressure is controlled by a remotely positioned metering pump responsive to the operation of the steering wheel by the operator. The pilot cylinder is connected to the linkage and to the steering valve to provide a follow-up effect through the pilot cylinder and steering valve. This system permits the use of a relatively high pressure sub-system for operating the power cylinders and a relatively low pressure sub-system controlled by the operator at a position remote from the steering mechanism for controlling the power cylinders.
Inventors
- 👤 D Stevens
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 15:32
CPC Classifications
B; B62; B62D; B62D5/00; B62D5/06; B62D5/10; B62D5/12
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
166 words
A hydraulic steering system for vehicular equipment having an operator controlled steering means, two steerable wheels, an axle bed for the wheels and a linkage interconnecting said wheels: said system comprising a hydraulic motor means connected to said linkage, a source of hydraulic fluid under relatively high pressure, a line connecting said source with said motor means, a steering valve disposed in said line and mounted on said axle bed for controlling the operation of said motor means, a hydraulic pilot cylinder means mounted on said axle bed and haVing two relatively movable operating parts for actuating said valve, means connecting one of said parts to said steering valve, means connecting the other of said parts to said linkage for obtaining a follow-up effect through said cylinder means and valve, a fluid supply means for said pilot cylinder, and a fluid metering means controlled by said steering means for controlling the flow of fluid in said fluid supply means and thereby controlling said pilot cylinder means.
Claim 2
Dependent Claim
166 words
A hydraulic steering system for vehicular equipment having an operator controlled steering means, two steerable wheels, an axle bed for the wheels and a linkage interconnecting said wheels: said system comprising a hydraulic motor means connected to said linkage, a source of hydraulic fluid under relatively high pressure, a line connecting said source with said motor means, a steering valve disposed in said line and mounted on said axle bed for controlling the operation of said motor means, a hydraulic pilot cylinder means mounted on said axle bed and haVing two relatively movable operating parts for actuating said valve, means connecting one of said parts to said steering valve, means connecting the other of said parts to said linkage for obtaining a follow-up effect through said cylinder means and valve, a fluid supply means for said pilot cylinder, and a fluid metering means controlled by said steering means for controlling the flow of fluid in said fluid supply means and thereby controlling said pilot cylinder means.
Claim 3
Dependent Claim
28 words
A hydraulic steering system for vehicular equipment as defined in claim 1 in which said fluid metering means controlled by said steering means consists of a metering pump.
Claim 4
Dependent Claim
38 words
A hydraulic steering system for vehicular equipment as defined in claim 1 in which said hydraulic motor means consists of two hydraulic cylinders, each connected to the axle bed and having pistons connected by rods to said linkage.
Claim 5
Dependent Claim
52 words
A hydraulic steering system for vehicular equipment as defined in claim 3 in which said relatively movable parts of said hydraulic pilot cylinder means includes a piston and a piston rod, means connecting said piston rod to said linkage, and means connecting the cylinder of said cylinder means to said steering valve.
Claim 6
Dependent Claim
28 words
A hydraulic steering system for vehicular equipment as defined in claim 4 in which said fluid metering means controlled by said steering means consists of a metering pump.
Claim 7
Dependent Claim
75 words
A hydraulic steering system for vehicular equipment as defined in claim 1 in which the linkage includes a spider mounted on said axle bed and movable angularly on a horizontal axis and a tie rod and steering arm connecting the spider with the axle of each steerable wheel, and in which said hydraulic motor means consists of cylinder means having one end anchored on said axle bed and the other end connected to said spider.
Claim 8
Dependent Claim
27 words
A hydraulic steering system for vehicular equipment as defined in claim 6 in which said hydraulic motor means includes a piston rod pivotedly connected to said spider.
Claim 9
Dependent Claim
28 words
A hydraulic steering system for vehicular equipment as defined in claim 7 in which said fluid metering means controlled by said steering means consists of a metering pump.
Claim 10
Dependent Claim
52 words
A hydraulic steering system for vehicular equipment as defined in claim 1 in which said relatively movable parts of said hydraulic pilot cylinder means includes a piston and a piston rod, means connecting said piston rod to said linkage, and means connecting the cylinder of said cylinder means to said steering valve.
Claim 11
Dependent Claim
75 words
A hydraulic steering system for vehicular equipment as defined in claim 9 in which the linkage includes a spider mounted on said axle bed and movable angularly on a horizontal axis, and a tie rod and steering arm connecting the spider with the axle of each steerable wheel, and in which said hydraulic motor means consists of cylinder means having one end anchored on said axle bed and the other end connected to said spider.
Claim 12
Dependent Claim
27 words
A hydraulic steering system for vehicular equipment as defined in claim 10 in which said hydraulic motor means includes a piston rod pivotedly connected to said spider.
Claim 13
Dependent Claim
28 words
A hydraulic steering system for vehicular equipment as defined in claim 11 in which said fluid metering means controlled by said steering means consists of a metering pump.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-08-13 | 1977-02-12 | 1977-08-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-13 | 1981-02-12 | 1981-08-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-13 | 1985-02-12 | 1985-08-14 | $7700.00 | Window Closed / Lapsed |