Patent US3760689A successfully refreshed from Google Patents.
US3760689A
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Control system for automatically sequencing operation of a plurality of hydraulic pumps for supplying a plurality of hydraulic actuators
Assignee: Harnischfeger Corp
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Filing: 1972-02-24
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Granted: 1973-09-25
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Expires: 1992-02-24
Abstract
Abstract A machine such as a mobile hydraulic crane has a telescopic boom comprising two independently movable boom sections. Each boom section is movable to extended and retracted positions by separate independently operable hydraulic actuators. Each actuator is operated or controlled by a manually operable three position hydraulic control valve. A plurality of hydraulic pumps are provided for supplying the actuators and a control system including a pressure-responsive sequencing valve is provided for automatically and sequentially connecting one or more pumps to supply the cylinders, depending on the number of cylinders that are being actuated at any given time. The sequencing valve responds to a pressure increase which occurs in the event the supply lines to both actuators are operated simultaneously in the boom-extend direction. If either actuator is being operated in the boom-extend direction, only one pump is connected to supply it. If more than one actuator is being operated in the boomextend direction, more than one pump is then automatically connected to supply fluid to the system by the pressureresponsive sequencing valve.
Inventors
- 👤 R Johnston
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 23:07
CPC Classifications
E; E02; E02F; E02F9/00; E02F9/20; E02F9/22; E02F9/2221; E02F9/2239; E02F9/2278; E02F9/2292; F; F15; F15B; F15B11/00; F15B11/16; F15B11/17; F15B2211/00; F15B2211/20; F15B2211/205; F15B2211/20576; F15B2211/50; F15B2211/505; F15B2211/50509; F15B2211/50536; F15B2211/515; F15B2211/5151; F15B2211/60; F15B2211/605; F15B2211/6058; F15B2211/70; F15B2211/71; F15B2211/7142
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
230 words
A machine having a telescopic boom comprising a plurality of boom sections, each movable to extended and retracted positions, a plurality of individually operable hydraulic actuators for moving said boom sections, each actuator being operable in boom extend and boom retract directions, one actuator being provided for each boom section, a multiposition control valve for each actuator, said control valve having neutral, extend and retract positions, a fluid supply line connected between each control valve and its associated actuator to effect operation of the actuator in the boom extend direction, a plurality of pumps for supplying hydraulic fluid to said actuators through said control valves, a pressure responsive sequencing valve having a pressure port, a fluid pressure line connected between each of said supply lines and said pressure port, and a flow control device connected in each fluid pressure line, said sequencing valve being connected between said pumps and said control valves and operable in response to fluid flow conditions to said actuators to connect one pump for fluid supply purposes when one actuator is operating in either the boom extend or retract direction when the control valve therefor is moved from neutral and to connect more than one pump for fluid supply purposes when more than one actuator is operating in the boom extend direction when all of the control valves therefor are moved from neutral to extend position.
Claim 2
Dependent Claim
230 words
A machine having a telescopic boom comprising a plurality of boom sections, each movable to extended and retracted positions, a plurality of individually operable hydraulic actuators for moving said boom sections, each actuator being operable in boom extend and boom retract directions, one actuator being provided for each boom section, a multiposition control valve for each actuator, said control valve having neutral, extend and retract positions, a fluid supply line connected between each control valve and its associated actuator to effect operation of the actuator in the boom extend direction, a plurality of pumps for supplying hydraulic fluid to said actuators through said control valves, a pressure responsive sequencing valve having a pressure port, a fluid pressure line connected between each of said supply lines and said pressure port, and a flow control device connected in each fluid pressure line, said sequencing valve being connected between said pumps and said control valves and operable in response to fluid flow conditions to said actuators to connect one pump for fluid supply purposes when one actuator is operating in either the boom extend or retract direction when the control valve therefor is moved from neutral and to connect more than one pump for fluid supply purposes when more than one actuator is operating in the boom extend direction when all of the control valves therefor are moved from neutral to extend position.
Claim 3
Dependent Claim
331 words
A machine having a telescopic boom comprising a plurality of boom sections, each boom section being movable between extended and retracted positions: a pair of pumps; an engine for driving said pumps; a two-position pressure responsive sequencing valve having a fluid output port, two fluid inlet ports, each of said inlet ports being connected to one of said pumps, and a pressure port, said sequencing valve normally connecting one of said pumps to provide fluid at said fluid output port and said sequencing valve being responsive to application of a predetermined fluid pressure at its pressure port to connect both of said pumps to provide fluid at said fluid output port; a plurality of individually operable hydraulic actuators for moving said boom sections, one actuator being provided for each boom section and each actuator having a pair of fluid ports, each actuator movable in extend and retract directions depending on which of its fluid ports is pressurized; a plurality of manually operable multiposition control valves for effecting operation of said actuators, one control valve being provided for each actuator and each contrOl valve having a pair of fluid ports connected to the pair of fluid ports on its associated actuator, each control valve having a neutral, extend and retract position, each control valve having a fluid inlet port connected to said fluid output port of said sequencing valve; fluid lines connected between the pressure port of said sequencing valve and one port of each said pairs of fluid ports of said control valves; and a flow control device in each of said fluid lines; said sequencing valve being responsive to pressurization of one of said fluid lines in response to operation of any one of said control valves to the extend position to connect one of said pumps to a selected actuator, said sequencing valve being responsive to operation of more than one of said control valves to extend position to connect said pair of pumps to said plurality of actuators.
Claim 4
Dependent Claim
331 words
A machine having a telescopic boom comprising a plurality of boom sections, each boom section being movable between extended and retracted positions: a pair of pumps; an engine for driving said pumps; a two-position pressure responsive sequencing valve having a fluid output port, two fluid inlet ports, each of said inlet ports being connected to one of said pumps, and a pressure port, said sequencing valve normally connecting one of said pumps to provide fluid at said fluid output port and said sequencing valve being responsive to application of a predetermined fluid pressure at its pressure port to connect both of said pumps to provide fluid at said fluid output port; a plurality of individually operable hydraulic actuators for moving said boom sections, one actuator being provided for each boom section and each actuator having a pair of fluid ports, each actuator movable in extend and retract directions depending on which of its fluid ports is pressurized; a plurality of manually operable multiposition control valves for effecting operation of said actuators, one control valve being provided for each actuator and each contrOl valve having a pair of fluid ports connected to the pair of fluid ports on its associated actuator, each control valve having a neutral, extend and retract position, each control valve having a fluid inlet port connected to said fluid output port of said sequencing valve; fluid lines connected between the pressure port of said sequencing valve and one port of each said pairs of fluid ports of said control valves; and a flow control device in each of said fluid lines; said sequencing valve being responsive to pressurization of one of said fluid lines in response to operation of any one of said control valves to the extend position to connect one of said pumps to a selected actuator, said sequencing valve being responsive to operation of more than one of said control valves to extend position to connect said pair of pumps to said plurality of actuators.
Claim 5
Dependent Claim
18 words
A machine according to claim 2 comprising two movable boom sections, two hydraulic actuators and two control valves.
References Cited (Backward Citations)
US2643516A
Cited
US2797551A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-09-24 | 1977-03-26 | 1977-09-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-24 | 1981-03-26 | 1981-09-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-24 | 1985-03-26 | 1985-09-25 | $7700.00 | Window Closed / Lapsed |