US4017218A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dual-speed setting underspeed system
Assignee: Caterpillar Inc
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Filing: 1976-03-15
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Granted: 1977-04-12
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Expires: 1996-03-15
Abstract
Abstract A hydraulic power system having a plurality of variable displacement pumps for supplying pressurized fluid for manipulation of an implement includes a control system operative to automatically adjust pump displacement to the output horsepower of a prime mover driving the pumps of the system. The control system includes underspeed valve means responsive to a deviation in the speed of the prime mover from a predetermined normal speed and a selectable second speed to transmit a fluid pressure signal to a servocontrol means for adjusting the displacement of the pumps. The control system includes a valve for selectively conditioning the control system to cause the underspeed valve to respond to a deviation of the selected engine speed and an indicator for indicating the conditioning of the control system.
Inventors
- 👤 Duane L. Burk
- 👤 Huber A. Moore
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 21:38
CPC Classifications
F; F04; F04B; F04B49/00; F04B49/007; F04B49/002; F15; F15B; F15B11/00; F15B11/16; F15B11/17; F16; F16H; F16H61/00; F16H61/38; F16H61/40; F16H61/46; F16H61/465; F15B2211/00; F15B2211/20; F15B2211/205; F15B2211/2053; F15B2211/20538; F15B2211/20546; F15B2211/20553; F15B2211/40; F15B2211/405; F15B2211/40515; F15B2211/40576; F15B2211/40592; F15B2211/415; F15B2211/41509; F15B2211/41518; F15B2211/42; F15B2211/428; F15B2211/455; F15B2211/60; F15B2211/605; F15B2211/6051; F15B2211/6054; F15B2211/70; F15B2211/71; F15B2211/7142
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
173 words
A hydraulic system comprising the combination of a horsepower-controlling system for controlling the horsepower output of a plurality of variable displacement pumps driven by a single prime mover, a source of pilot pressure including a fixed displacement pump driven by said prime mover for controlling displacement of said pumps in relation to the speed output of said prime mover, underspeed control valve means responsive to a deviation from either one of a predetermined normal operating speed of said prime mover and a second predetermined operating speed less than said normal speed controlling the communication of said pilot control pressure with said pump displacement means to thereby vary the displacement of said pumps in proportion to load thereon, and adjustable means for selectively adjusting said pilot control pressure so that the response of said underspeed valve is to a deviation from a selected one of said normal operating speed and said second operating speed, the improvement comprising pilot pressure-responsive indicator means for indicating said predetermined normal operating speed and said second predetermined operating speed.
Claim 2
Dependent Claim
173 words
A hydraulic system comprising the combination of a horsepower-controlling system for controlling the horsepower output of a plurality of variable displacement pumps driven by a single prime mover, a source of pilot pressure including a fixed displacement pump driven by said prime mover for controlling displacement of said pumps in relation to the speed output of said prime mover, underspeed control valve means responsive to a deviation from either one of a predetermined normal operating speed of said prime mover and a second predetermined operating speed less than said normal speed controlling the communication of said pilot control pressure with said pump displacement means to thereby vary the displacement of said pumps in proportion to load thereon, and adjustable means for selectively adjusting said pilot control pressure so that the response of said underspeed valve is to a deviation from a selected one of said normal operating speed and said second operating speed, the improvement comprising pilot pressure-responsive indicator means for indicating said predetermined normal operating speed and said second predetermined operating speed.
Claim 3
Dependent Claim
46 words
The hydraulic system of claim 1 wherein: said adjustable means comprises an orifice connected in parallel with said underspeed control valve means, and a valve for controlling the flow of fluid through said orifice for adjusting the flow of fluid through said underspeed control valve means.
Claim 4
Dependent Claim
39 words
The hydraulic system of claim 2 wherein said valve is biased to a first predetermined position for permitting free flow through said orifice and is shiftable to a second position for blocking the flow of fluid through said orifice.
Claim 5
Independent Claim
198 words
A method of adjusting the operation of a hydraulic system comprising the combination of a horsepower-controlling system for controlling the horsepower output of a plurality of variable displacement pumps driven by a single prime mover, a source of pilot pressure including a fixed displacement pump driven by said prime mover for controlling displacement of said pumps in relation to the speed output of said prime mover, underspeed control valve means responsive to a deviation from either one of a predetermined normal operating speed of said prime mover and a second predetermined operating speed less than said normal speed controlling the communication of said pilot control pressure with said pump displacement means to thereby vary the displacement of said pumps in proportion to load thereon, and adjustable means for selectively adjusting said pilot control pressure so that the response of said underspeed valve is to a deviation from a selected one of said normal operating speed and said second operating speed comprising the steps of: providing pilot pressure-responsive indicator means for indicating said predetermined normal operating speed and said second predetermined operating speed; and, adjusting the speed of said prime mover until one of said operating speeds is obtained.
Claim 6
Independent Claim
198 words
A method of adjusting the operation of a hydraulic system comprising the combination of a horsepower-controlling system for controlling the horsepower output of a plurality of variable displacement pumps driven by a single prime mover, a source of pilot pressure including a fixed displacement pump driven by said prime mover for controlling displacement of said pumps in relation to the speed output of said prime mover, underspeed control valve means responsive to a deviation from either one of a predetermined normal operating speed of said prime mover and a second predetermined operating speed less than said normal speed controlling the communication of said pilot control pressure with said pump displacement means to thereby vary the displacement of said pumps in proportion to load thereon, and adjustable means for selectively adjusting said pilot control pressure so that the response of said underspeed valve is to a deviation from a selected one of said normal operating speed and said second operating speed comprising the steps of: providing pilot pressure-responsive indicator means for indicating said predetermined normal operating speed and said second predetermined operating speed; and, adjusting the speed of said prime mover until one of said operating speeds is obtained.
Claim 7
Dependent Claim
98 words
The method of claim 4 wherein said adjustable means comprises an orifice connected in parallel with said underspeed control valve means and a valve for controlling the flow of fluid through said orifice for adjusting the flow of fluid through said underspeed control valve means, and said method includes the steps of shifting said valve to a first position for permitting free flow through said orifice for selecting one of said operating speeds, and shifting said valve to a second position for blocking the flow of fluid through said orifice for selecting the other of said operating positions.
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) | 1980-04-11 | 1980-10-11 | 1981-04-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-04-11 | 1984-10-11 | 1985-04-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-04-11 | 1988-10-11 | 1989-04-12 | $7700.00 | Window Closed / Lapsed |