US4664210A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydraulic steering system
Assignee: Kanzaki Kokyukoki Manufacturing Co Ltd
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Filing: 1986-01-17
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Granted: 1987-05-12
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Expires: 2006-01-17
Abstract
Abstract A hydraulic steering system for use in four-wheel running vehicles or the like of small size and low horsepower. The steering system and a hydraulic system for lifting a working implement are both operable by a single hydraulic pump without the necessity of using a variable displacement hydraulic pump or providing two hydraulic pumps for the two systems. The steering system is operable by an engine of low horsepower.
Inventors
- 👤 Kojiro Yamaoka
- 👤 Toshiro Azuma
- 👤 Shigenori Sakikawa
- 👤 Jiro Shibata
- 👤 Atsushi Odagaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 08:32
CPC Classifications
B; B62; B62D; B62D5/00; B62D5/06; B62D5/07
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
166 words
In a four-wheel running vehicle having hydraulic steering means and a hydraulic system C for lifting a working implement, a hydraulic steering system characterized in that the steering system comprises steering hydraulic valve means A having a first end connected to a housing and a second end connected to a spool moveable within said housing, said valve means A being connected so that a working fluid from a hydraulic pump 23 operable by a drive engine E is fed through the hydraulic valve means A to hydraulic valve means 26 of the hydraulic lifting system C in series with the valve means A, the steering hydraulic valve means A having one end connected to a pitman arm 3 and the other end connected to means for operating knuckle arms 9, a bypass being provided in parallel with the steering hydraulic valve means A having a relief valve 7, and a check valve 6 openable in response to a negative pressure in a steering hydraulic cylinder 8.
Claim 2
Dependent Claim
166 words
In a four-wheel running vehicle having hydraulic steering means and a hydraulic system C for lifting a working implement, a hydraulic steering system characterized in that the steering system comprises steering hydraulic valve means A having a first end connected to a housing and a second end connected to a spool moveable within said housing, said valve means A being connected so that a working fluid from a hydraulic pump 23 operable by a drive engine E is fed through the hydraulic valve means A to hydraulic valve means 26 of the hydraulic lifting system C in series with the valve means A, the steering hydraulic valve means A having one end connected to a pitman arm 3 and the other end connected to means for operating knuckle arms 9, a bypass being provided in parallel with the steering hydraulic valve means A having a relief valve 7, and a check valve 6 openable in response to a negative pressure in a steering hydraulic cylinder 8.
Claim 3
Dependent Claim
28 words
A hydraulic steering system as defined in claim 1 wherein the check valve 6 and the relief valve 7 are incorporated in the steering hydraulic valve means A.
Claim 4
Dependent Claim
79 words
A hydraulic steering system as defined in claim 1 wherein the steering hydraulic valve means A is of the tandem-center type when in its neutral position, and the steering hydraulic cylinder 8 is of the single piston rod type, wherein a fluid channel in the steering hydraulic valve means for the hydraulic lifting system C is prevented from communicating with fluid channels in the steering hydraulic valve means connected to opposite chambers of the steering hydraulic cylinder 8 simultaneously.
Claim 5
Dependent Claim
136 words
A hydraulic steering system as defined in claim 1 wherein the steering hydraulic valve means A is of the open-center type when in its neutral position, the steering hydraulic cylinder 8 is of the single piston rod type, and a spring 14 is provided and supplies a biasing force on the spool of the steering valve means A urging the spool toward its neutral position, said biasing force being greater than the force required for rotating the pitman arm 3 from the drag rod side, so that when the steering hydraulic valve means A is in its neutral position and when the steering hydraulic cylinder 8 is extended by a change of the hydraulic pressure of the lifting system C, the force of the extension is not delivered to a steering wheel 2 of the vehicle.
Claim 6
Dependent Claim
33 words
A hydraulic steering system as defined in claim 1 wherein a flow control valve 30 is disposed in parallel with the valve means A, the relief valve 7 and the check valve 6.
Claim 7
Dependent Claim
52 words
A hydraulic steering system as defined in claim 1 wherein the steering hydraulic cylinder 8 is of the single piston rod type, and the output Pa of the rod-side fluid chamber of the cylinder 8 is always positive relative to variations in the lift pressure P2 of the hydraulic lifting system C.
References Cited (Backward Citations)
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Cited
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Cited
US4174018A
Cited
US4213511A
Cited
US4500250A
Cited
US4470260A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-05-11 | 1990-11-10 | 1991-05-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-05-11 | 1994-11-10 | 1995-05-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-05-11 | 1998-11-10 | 1999-05-12 | $7700.00 | Window Closed / Lapsed |