Patent US3797245A successfully refreshed from Google Patents.
US3797245A
Expired / Lapsed
US
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Dual range pressure dependent variable flow fluid delivery system
Assignee: Caterpillar Inc
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Filing: 1972-08-25
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Granted: 1974-03-19
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Expires: 1992-08-25
Abstract
Abstract Using a variable displacement pump as a source of pressurized fluid in a pressurized fluid delivery circuit, the displacement of the pump can be controlled by pressure in the fluid delivery circuit over a first pressure compensated range when work circuits connected thereto are capable of being operated within the first pressure range and also at a second higher pressure compensated range if any work circuit requires a higher pressure by using the pressure above a preselected value in the work circuit to change the range pressure compensation to a higher level through adjustment of control components.
Inventors
- 👤 A Hein
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 09:54
CPC Classifications
F; F15; F15B; F15B11/00; F15B11/02; F04; F04B; F04B49/00; F04B49/002; F04B49/08; F15B11/16; F15B11/161; F15B11/165; F15B2211/00; F15B2211/20; F15B2211/205; F15B2211/20507; F15B2211/20515; F15B2211/2053; F15B2211/20546; F15B2211/20553; F15B2211/25; F15B2211/30; F15B2211/305; F15B2211/30505; F15B2211/3051; F15B2211/30525; F15B2211/3053; F15B2211/30535; F15B2211/31; F15B2211/3105; F15B2211/3111; F15B2211/315; F15B2211/3157; F15B2211/31576; F15B2211/50; F15B2211/505; F15B2211/50509; F15B2211/50518; F15B2211/55; F15B2211/60; F15B2211/605; F15B2211/6051; F15B2211/6052; F15B2211/6054; F15B2211/6058; F15B2211/70; F15B2211/705; F15B2211/7051; F15B2211/7053; F15B2211/7054
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
189 words
A dual range pressure compensated fluid delivery system giving pressure compensated output flow over two independent pressure ranges comprising: a variable displacement pump driven by a prime mover and having an inlet connected to a source of hydraulic fluid and an outlet delivering pressurized fluid; a fluid delivery circuit connected to said output having at least one work circuit connected thereto; an actuator system connected to said pump to control its displacement, pressure responsive control means operably associated with said actuator system and having communication with said outlet of said pump whereby an output flow of said pump is proportional to its outlet pressure over a part of its displacement within a first preselected pressure range; and pressure responsive valve means in communication with pressure in said fluid delivery circuit and associated with said pressure responsive control means, said pressure responsive valve means operable above a preselected pressure to adjust said control means whereby said output flow of said pump is proportional to its outlet over part of its displacement within a second preselected pressure range, said second preselected pressure range being higher than said first preselected pressure range.
Claim 2
Dependent Claim
189 words
A dual range pressure compensated fluid delivery system giving pressure compensated output flow over two independent pressure ranges comprising: a variable displacement pump driven by a prime mover and having an inlet connected to a source of hydraulic fluid and an outlet delivering pressurized fluid; a fluid delivery circuit connected to said output having at least one work circuit connected thereto; an actuator system connected to said pump to control its displacement, pressure responsive control means operably associated with said actuator system and having communication with said outlet of said pump whereby an output flow of said pump is proportional to its outlet pressure over a part of its displacement within a first preselected pressure range; and pressure responsive valve means in communication with pressure in said fluid delivery circuit and associated with said pressure responsive control means, said pressure responsive valve means operable above a preselected pressure to adjust said control means whereby said output flow of said pump is proportional to its outlet over part of its displacement within a second preselected pressure range, said second preselected pressure range being higher than said first preselected pressure range.
Claim 3
Dependent Claim
23 words
The dual range pressure compensated fluid delivery system defined in claim 1 wherein the variable displacement pump is of the axial pistoN type.
Claim 4
Dependent Claim
35 words
The dual range pressure compensated fluid delivery system defined in claim 1 wherein the fluid delivery circuit includes at least one closed center valve between the fluid delivery circuit and at least one work circuit.
Claim 5
Dependent Claim
38 words
The dual range pressure compensated fluid delivery system defined in claim 3 wherein the pressure responsive valve means is in communication with a portion of the fluid delivery circuit downstream of said at least one closed center valve.
Claim 6
Dependent Claim
55 words
The dual range pressure compensated fluid delivery system defined in claim 4 wherein a locking valve is disposed between the fluid delivery circuit and at least one work circuit whereby pressures in a hydraulic motor in said work circuit cannot activate the pressure responsive valve means unless its associated closed center control valve is actuated.
Claim 7
Dependent Claim
77 words
The dual range pressure compensated fluid delivery system defined in claim 3 wherein a plurality of closed center control valves are disposed between the fluid delivery circuit and a corresponding number of work circuits, each control valve operable to actuate a separate work circuit, and common conduit means connecting each of the control valves with the pressure responsive valve means through one way check valves whereby any work circuit activated can operate said pressure responsive valve means.
Claim 8
Dependent Claim
72 words
The dual range pressure compensated fluid delivery system defined in claim 1 wherein the actuator system includes two pressure responsive members, one of said pressure responsive members in communication with pump output pressure and having biasing means associated therewith and wherein the pressure responsive control means includes a servo-valve means associated with one of said pressure responsive members operable to control the actuator system as a function of said pump output pressure.
Claim 9
Dependent Claim
38 words
The dual range pressure compensated fluid delivery system defined in claim 7 wherein the pressure responsive valve means activates additional biasing means on the servo-valve means thereby causing the pump to operate within the second preselected pressure range.
Claim 10
Dependent Claim
25 words
The dual range pressure compensated fluid delivery system defined in claim 7 wherein the additional biasing means includes a reacting surface operated by pump pressure.
References Cited (Backward Citations)
US2512799A
Cited
US3366064A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-03-18 | 1977-09-17 | 1978-03-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-18 | 1981-09-17 | 1982-03-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-18 | 1985-09-17 | 1986-03-19 | $7700.00 | Window Closed / Lapsed |