US4017216A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Variable underspeed system linkage
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 one or more implements includes control means operative to automatically adjust pump displacement to the output horsepower of a prime mover driving the pumps of the system. The control system includes an underspeed valve responsive to a deviation in the speed of the prime mover from any of a wide range of selected speeds to transmit a fluid pressure signal to servocontrol means for adjusting the displacement of the pumps. The underspeed control means includes an infinitely variable orifice connected by way of lost motion linkage to the engine throttle control for adjusting the underspeed valves to respond to a deviation of an infinite range of engine speeds.
Inventors
- 👤 Huber A. Moore
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 14:03
CPC Classifications
E; E02; E02F; E02F9/00; E02F9/20; E02F9/22; E02F9/2278; E02F9/2296; E02F9/2221; E02F9/2232; E02F9/2239; E02F9/2292; F; F04; F04B; F04B49/00; F04B49/007; F04B49/10; F04B49/103; F15; F15B; F15B11/00; F15B11/16; F15B11/17; F15B2211/00; F15B2211/20; F15B2211/205; F15B2211/2053; F15B2211/20538; F15B2211/20546; F15B2211/20553; F15B2211/20576; F15B2211/40; F15B2211/405; F15B2211/40515; F15B2211/40576; F15B2211/40592; F15B2211/415; F15B2211/41509; F15B2211/41518; F15B2211/42; F15B2211/426; F15B2211/428; F15B2211/455; F15B2211/60; F15B2211/605; F15B2211/6051; F15B2211/6054; F15B2211/70; F15B2211/71; F15B2211/7142
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
188 words
A hydraulic system comprising the combination of a plurality of variable displacement pumps driven by a single prime mover, and a horsepower-controlling system for controlling the horsepower output of the variable displacement pumps, including a source of pilot pressure including a fixed displacement pump driven by a prime mover for controlling displacement of said pumps in relation to the speed output of said prime mover, throttle control means for controllably selecting the speed of said prime mover, underspeed control valve means responsive to a deviation from selected operating speeds of said prime mover for normally controlling the communication of said pilot control pressure with said pump displacement means to thereby vary the displacement of said pumps in proportion to loads thereon, and infinitely variable means movable with said throttle control means for adjusting the response of said underspeed valve to respond to a deviation from said operating speed, the improvement comprising: lost motion linkage means connecting said infinitely variable means to said throttle control means for movement of said infinitely variable means with said throttle control means only after said throttle control means has advanced a predetermined amount.
Claim 2
Dependent Claim
188 words
A hydraulic system comprising the combination of a plurality of variable displacement pumps driven by a single prime mover, and a horsepower-controlling system for controlling the horsepower output of the variable displacement pumps, including a source of pilot pressure including a fixed displacement pump driven by a prime mover for controlling displacement of said pumps in relation to the speed output of said prime mover, throttle control means for controllably selecting the speed of said prime mover, underspeed control valve means responsive to a deviation from selected operating speeds of said prime mover for normally controlling the communication of said pilot control pressure with said pump displacement means to thereby vary the displacement of said pumps in proportion to loads thereon, and infinitely variable means movable with said throttle control means for adjusting the response of said underspeed valve to respond to a deviation from said operating speed, the improvement comprising: lost motion linkage means connecting said infinitely variable means to said throttle control means for movement of said infinitely variable means with said throttle control means only after said throttle control means has advanced a predetermined amount.
Claim 3
Dependent Claim
54 words
The hydraulic system of claim 1 wherein said variable means comprises variable flow control means including valve means connected in parallel with said underspeed control valve means, said valve means connected to said throttle control means by said lost motion linkage means 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 lost motion means is a chain having sufficient slack for said engine throttle to advance to a predetermined minimum speed of said prime mover prior to movement of said valve means.
References Cited (Backward Citations)
US3963378A
Cited
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 |