Patent US3686862A successfully refreshed from Google Patents.
US3686862A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydraulic system for single engine truck crane or the like
Assignee: NORTHWEST ENGINEERING Co A CORP OF
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Filing: 1971-04-14
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Granted: 1972-08-29
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Expires: 1991-04-14
Abstract
Abstract A hydraulic system for a single engine truck crane includes a pump input section in the carrier that is driven by the carrier engine and an output section in the upper works. A closed loop connects the input and output sections and requires only two passages through the swivel joint. The working reservoir is in the upper works, and a supercharge pump in the upper works is driven by the output section and draws from the reservoir to feed the loop. In one embodiment the output section comprises a flow divider leading to valve units and working motors which are incorporated in the closed loop, and in another embodiment the output section includes a power motor which is driven by the pump in the carrier and which drives working pumps in the upper works that serve the working motors.
Inventors
- 👤 Lyle D Grider
- 👤 John T Hornagold
- 👤 Ram N Rathi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 23:08
CPC Classifications
F; F15; F15B; F15B11/00; F15B11/16; F15B11/17; B; B66; B66C; B66C13/00; B66C13/18; B66C2700/00; B66C2700/06
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
144 words
A hydraulic operating system for a truck crane or the like including a carrier with an engine, an upper works revolvably mounted on the carrier and a hydraulic swivel joint interposed between the carrier and upper works, said system comprising: a pump input section mounted in the carrier and driven by the engine; an output section in the upper works; a closed hydraulic loop connecting the input and output sections, the loop including a single pressure line leading from the input section through the swivel joint into the upper works and a single return line leading from the upper works through the swivel joint to the input section; a fluid reservoir in the upper works that supplies substantially alL of the working fluid for the system; and a supercharge pump that draws from the reservoir and serves to pump fluid into the closed loop.
Claim 2
Dependent Claim
144 words
A hydraulic operating system for a truck crane or the like including a carrier with an engine, an upper works revolvably mounted on the carrier and a hydraulic swivel joint interposed between the carrier and upper works, said system comprising: a pump input section mounted in the carrier and driven by the engine; an output section in the upper works; a closed hydraulic loop connecting the input and output sections, the loop including a single pressure line leading from the input section through the swivel joint into the upper works and a single return line leading from the upper works through the swivel joint to the input section; a fluid reservoir in the upper works that supplies substantially alL of the working fluid for the system; and a supercharge pump that draws from the reservoir and serves to pump fluid into the closed loop.
Claim 3
Dependent Claim
38 words
A hydraulic operating system according to claim 1 wherein the supercharge pump is in the upper works and is driven by the output section and pumps fluid into the closed loop at a point in the upper works.
Claim 4
Dependent Claim
111 words
A hydraulic operating system according to claim 2 wherein: the upper works includes a plurality of control valve units with each unit adapted to have a closed loop connection with at least one working motor and to supply all pressure fluid to and receive all return fluid from the working motor; and the output section comprises a flow divider connected to the pressure line; and there are a plurality of outputs from the flow divider which lead to respective valve units; and return fluid from all of the valve units enters the return line in the upper works; and an output line from the supercharge pump leads to the return line.
Claim 5
Dependent Claim
105 words
A hydraulic operating system according to claim 3 wherein: at least one valve unit serves at least one working motor which is a double acting cylinder that requires more fluid for extension than for retraction and returns more fluid during retraction than during extension; and the supercharge pump is adapted to supply the extra fluid required for extension; and there is a relief line leading from the return line to the reservoir which includes pressure relief valve means, the pressure relief valve means serving to limit the output pressure of the supercharge pump and to dispose of excess fluid entering the return line during retraction.
Claim 6
Dependent Claim
56 words
A hydraulic operating system according to claim 4 wherein the pressure relief valve means includes two pressure relief valves in parallel, one of which opens at a certain predetermined pressure to control the output pressure of the supercharge pump and the other of which opens at a higher predetermined pressure to dispose of excess return fluid.
Claim 7
Dependent Claim
54 words
A hydraulic operating system according to claim 3 wherein: there is a cooling fan in the upper works that is driven by the flow divider; and there is an intermediate return line leading from one of the valve units to a point on the return line which includes a heat exchanger facing the fan.
Claim 8
Dependent Claim
51 words
A hydraulic operating system according to claim 2 wherein: there is at least one working pump in the upper works which draws from the reservoir; and the output section comprises a hydraulic power motor which is driven by the input section and which drives the working pump and the supercharge pump.
Claim 9
Dependent Claim
40 words
A hydraulic operating system according to claim 7 wherein: the upper works includes a plurality of valve units; and there are a corresponding number of working pumps all driven by the power motor, one working pump serving each valve unit.
Claim 10
Dependent Claim
47 words
A hydraulic operating system according to claim 8 wherein: an output line leads from the supercharge pump to the return line and includes a heat exchanger; and there is a fan in the upper works which is driven by the power motor and faces the heat exchanger.
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) | 1975-08-29 | 1976-02-28 | 1976-08-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-29 | 1980-02-28 | 1980-08-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-29 | 1984-02-28 | 1984-08-29 | $7700.00 | Window Closed / Lapsed |