US3760688A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Synchronized control system for telescoping booms
Assignee: NORTHWEST ENGINEERING Co A CORP OF
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Filing: 1971-11-09
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Granted: 1973-09-25
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Expires: 1991-11-09
Abstract
Abstract A fluid control circuit for driving a plurality of double-acting linear fluid actuators at proportional, synchronized rates to extend and retract a multi-section boom has a flow divider assembly that meters proportional amounts of operating fluid into and out of each of the rod ends of the actuators to maintain the synchronization of the actuators. The flow divider assembly includes a plurality of relief valves, each of which are connected between a rod end of one of the actuators and the circuit reservoir to provide a means for resynchronizing the actuators with one another.
Inventors
- 👤 R Dummer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 23:22
CPC Classifications
B; B66; B66C; B66C23/00; B66C23/62; B66C23/64; B66C23/70; B66C23/701; B66C23/705; F; F15; F15B; F15B11/00; F15B11/16; F15B11/22
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
344 words
A hydraulic control circuit for simultaneously synchronously driving at least two double acting hydraulic cylinders, the combination comprising: first and second double acting hydraulic cylinders, each cylinder containing a reciprocable piston with a rod projecting therefrom through one end of said cylinder, and each cylinder having a rod end enclosing said piston rod and a blind end on the opposite side of said piston; a reservoir of operating fluid with a pump to impel fluid under pressure to drive said first and second hydraulic cylinder; a directional control valve means connected to receive operating fluid under pressure from said reservoir and to return fluid to said reservoir, and adapted alternately to conduct said operating fluid under pressure out of either of at least two ports and to conduct fluid from the other of said two parts to said reservoir; a first circuit branch connecting one of said two ports of said directional control valve means to said blind ends of said first and second double acting hydraulic cylinders; and a second circuit branch connecting the other of said two ports of said directional control valve means to said rod ends of said first and second double acting hydraulic cylinder; said second circuit branch including a first pilot operated flow control valve means connected between said rod end of said first double acting hydraulic cylinder and said other port of said directional control valve means, a second pilot operated flow control valve means connected between said rod end of said second double acting hydraulic cylinder and said other port of said directional control valve means said first and second pilot operated flow control valve means being responsive to operating fluid pressure between the other pilot operated flow control valve means and said directional control valve means to shut said pilot operated flow control valve means when said operating fluid pressure falls below a predetermined minimum, and pressure responsive valves connecting each of said rods ends of said first and second double acting hydraulic cylinders to said reservoir when operating fluid pressure exceeds a predetermined maximum.
Claim 2
Dependent Claim
344 words
A hydraulic control circuit for simultaneously synchronously driving at least two double acting hydraulic cylinders, the combination comprising: first and second double acting hydraulic cylinders, each cylinder containing a reciprocable piston with a rod projecting therefrom through one end of said cylinder, and each cylinder having a rod end enclosing said piston rod and a blind end on the opposite side of said piston; a reservoir of operating fluid with a pump to impel fluid under pressure to drive said first and second hydraulic cylinder; a directional control valve means connected to receive operating fluid under pressure from said reservoir and to return fluid to said reservoir, and adapted alternately to conduct said operating fluid under pressure out of either of at least two ports and to conduct fluid from the other of said two parts to said reservoir; a first circuit branch connecting one of said two ports of said directional control valve means to said blind ends of said first and second double acting hydraulic cylinders; and a second circuit branch connecting the other of said two ports of said directional control valve means to said rod ends of said first and second double acting hydraulic cylinder; said second circuit branch including a first pilot operated flow control valve means connected between said rod end of said first double acting hydraulic cylinder and said other port of said directional control valve means, a second pilot operated flow control valve means connected between said rod end of said second double acting hydraulic cylinder and said other port of said directional control valve means said first and second pilot operated flow control valve means being responsive to operating fluid pressure between the other pilot operated flow control valve means and said directional control valve means to shut said pilot operated flow control valve means when said operating fluid pressure falls below a predetermined minimum, and pressure responsive valves connecting each of said rods ends of said first and second double acting hydraulic cylinders to said reservoir when operating fluid pressure exceeds a predetermined maximum.
Claim 3
Dependent Claim
172 words
A hydraulic control circuit as set forth in claim 1 wherein said first circuit branch includes a first normally closed pilot operated on-off valve means connected between the blind end of said first double acting hydraulic cylinder and said directional control valve means responsive to operating fluid pressure in said second circuit branch to open when said operating fluid pressure exceeds a predetermined maximum and a one way valve connected to conduct operating fluid under pressure from said directional control valve means to said blind end of said first double acting hydraulic cylinder, and a second normally closed pilot operated on-off valve means connected between the blind end of said second double acting hydraulic cylinder and said directional control valve means responsive to operating fluid pressure in said second circuit branch to open when said operating fluid pressure exceeds a predetermined maximum, and a one-way valve means connected to conduct said operating fluid under pressure from said directional control valve means to said blind end of said second double acting hydraulic cylinder.
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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) | 1976-09-24 | 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 |