US4638720A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electro-hydraulic control system
Assignee: Deere and Co
•
Filing: 1980-12-01
•
Granted: 1987-01-27
•
Expires: 2000-12-01
Abstract
Abstract An electro-hydraulic control system includes a plurality of two-position control valves, each controlling fluid flow into and out of a corresponding one of a plurality of hydraulic functions. First and second pressure responsive servo actuators associated with each control valve operate to move each control valve to first and second positions, respectively. A two-position, solenoid-operated, pilot valve controls fluid flow into and out of a pilot circuit. The pilot circuit communicates fluid to and from the second servo actuator of each control valve and to and from a plurality of two-position, soleniod-operated, pilot valves. Each pilot valve controls fluid flow into and out of the first servo actuator of a corresponding one of the control valves. A detent mechanism holds each control valve in either its first or its second position in the absence of fluid pressure in the servo actuators. A particular hydraulic function may be actuated by momentary energization of particular solenoids of the rest and/or the pilot valves.
Inventors
- 👤 Kevin D. McKee
- 👤 Charles W. Formwalt, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 22:33
CPC Classifications
F; F16; F16H; F16H61/00; F16H61/02; F16H61/0202; F16H61/0251; F16H61/0204; F16H61/0206; F16H2061/0209; F16H61/0262; F16H61/0276; F16H2061/0288; F16H61/12; F16H2061/1232; F16H2061/1236
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
124 words
An electro-hydraulic control system for a hydraulic system having a plurality of functions, the control system comprising: a plurality of two-position control valves for controlling the flow of fluid to and exhaust of fluid from the plurality of hydraulic functions; first and second servo means associated with each control valve responsive to fluid pressure to move the control valve to first and second positions, respectively; a two-position, solenoid-operated, reset valve for controlling the flow of fluid to and exhaust of fluid from the second servo means of the plurality of control valves; and a two-position, solenoid-operated, pilot valve associated with each control valve for controlling the flow of fluid to and exhaust of fluid from the first servo means of the associated control valve.
Claim 2
Dependent Claim
124 words
An electro-hydraulic control system for a hydraulic system having a plurality of functions, the control system comprising: a plurality of two-position control valves for controlling the flow of fluid to and exhaust of fluid from the plurality of hydraulic functions; first and second servo means associated with each control valve responsive to fluid pressure to move the control valve to first and second positions, respectively; a two-position, solenoid-operated, reset valve for controlling the flow of fluid to and exhaust of fluid from the second servo means of the plurality of control valves; and a two-position, solenoid-operated, pilot valve associated with each control valve for controlling the flow of fluid to and exhaust of fluid from the first servo means of the associated control valve.
Claim 3
Dependent Claim
37 words
The electro-hydraulic control system set forth in claim 1 wherein each control valve includes detent means for holding the control valve in the first and second positions in the absence of fluid pressure in the servo means.
Claim 4
Dependent Claim
174 words
An electro-hydraulic control system for a hydraulic system having a plurality of hydraulic functions, the control system comprising: a plurality of two-position control valves for controlling the flow of pressurized fluid to and exhaust of fluid from the hydraulic functions; first and second servo means associated with each control valve responsive to fluid pressure to move the control valve to first and second positions, respectively, the first servo means associated with each control valve being of a larger size than the second servo means; detent means associated with each control valve for holding the control valve in the first and second positions in the absence of fluid pressure in the servo means; a solenoid-operated pilot valve associated with each control valve for controlling the flow of pressurized fluid to and exhaust of fluid from the first servo means of the associated control valve; and a solenoid-operated reset valve for controlling the flow of fluid to and exhaust of fluid from the second servo means of the plurality of control valves and the pilot valves.
Claim 5
Dependent Claim
174 words
An electro-hydraulic control system for a hydraulic system having a plurality of hydraulic functions, the control system comprising: a plurality of two-position control valves for controlling the flow of pressurized fluid to and exhaust of fluid from the hydraulic functions; first and second servo means associated with each control valve responsive to fluid pressure to move the control valve to first and second positions, respectively, the first servo means associated with each control valve being of a larger size than the second servo means; detent means associated with each control valve for holding the control valve in the first and second positions in the absence of fluid pressure in the servo means; a solenoid-operated pilot valve associated with each control valve for controlling the flow of pressurized fluid to and exhaust of fluid from the first servo means of the associated control valve; and a solenoid-operated reset valve for controlling the flow of fluid to and exhaust of fluid from the second servo means of the plurality of control valves and the pilot valves.
Claim 6
Dependent Claim
223 words
An electro-hydraulic control system for a hydraulic system having a source of fluid pressure, a fluid reservoir, and a plurality of hydraulic functions, the control system comprising: a plurality of two-position control valves providing communication between the source and functions when in a first position and between the reservoir and functions when in a second position; first and second servo means associated with each control valve responsive to fluid pressure to move the associated control valve to its first and second positions, respectively, the first servo means being of a larger size than the second servo means; detent means associated with each control valve for holding the control valve in the first and second positions in the absence of fluid pressure in the servo means; fluid transfer means communicating with the second servo means of each control valve; a two-position, solenoid-operated, reset valve providing communication between the source and fluid transfer means when in a first position and between the fluid transfer means and the reservoir when in the second position; and a two-position, solenoid-operated, pilot valve associated with each control valve providing communication between the fluid transfer means and the first servo means of the associated control valve when in a first position and between the first servo means of the associated control valve and the reservoir when in a second position.
Claim 7
Dependent Claim
223 words
An electro-hydraulic control system for a hydraulic system having a source of fluid pressure, a fluid reservoir, and a plurality of hydraulic functions, the control system comprising: a plurality of two-position control valves providing communication between the source and functions when in a first position and between the reservoir and functions when in a second position; first and second servo means associated with each control valve responsive to fluid pressure to move the associated control valve to its first and second positions, respectively, the first servo means being of a larger size than the second servo means; detent means associated with each control valve for holding the control valve in the first and second positions in the absence of fluid pressure in the servo means; fluid transfer means communicating with the second servo means of each control valve; a two-position, solenoid-operated, reset valve providing communication between the source and fluid transfer means when in a first position and between the fluid transfer means and the reservoir when in the second position; and a two-position, solenoid-operated, pilot valve associated with each control valve providing communication between the fluid transfer means and the first servo means of the associated control valve when in a first position and between the first servo means of the associated control valve and the reservoir when in a second position.
Claim 8
Dependent Claim
41 words
An electro-hydraulic control system as set forth in claim 4 wherein the pilot valves and reset valve are each biased to its second position, each includes a solenoid, and each is moved to its second position upon energization of its solenoid.
Claim 9
Dependent Claim
36 words
An electro-hydraulic control system as set forth in claim 4 or 5 wherein the servo means are subjected to the same fluid pressure as the hydraulic functions when their respective valves are in the first positions.
Claim 10
Dependent Claim
43 words
An electro-hydraulic control system as set forth in claim 4 or 5 wherein the servo means are subjected to a fluid pressure less than the fluid pressure to which the hydraulic functions are subjected when their respective valves are in the first positions.
Claim 11
Dependent Claim
171 words
An electro-hydraulic control system for a hydraulic system having a source of fluid pressure, a fluid reservoir and a plurality of hydraulic functions, the control system comprising: a plurality of two-position control valves providing communication between the source and functions when in a first position and between the functions and reservoir when in a second position; first and second servo means associated with each control valve responsive to fluid pressure to move the associated control valve to its first and second positions, respectively; a two-position, solenoid-operated, pilot valve associated with each control valve providing communication between the source and first servo means of the associated control valve when in the first position and between the first servo means of the associated control valve and the reservoir when in the second position; and a two-position, solenoid-operated, reset valve providing communication between the source and the second servo means associated with each control valve when in a first position and between the second servo means and the reservoir when in a second position.
Claim 12
Dependent Claim
171 words
An electro-hydraulic control system for a hydraulic system having a source of fluid pressure, a fluid reservoir and a plurality of hydraulic functions, the control system comprising: a plurality of two-position control valves providing communication between the source and functions when in a first position and between the functions and reservoir when in a second position; first and second servo means associated with each control valve responsive to fluid pressure to move the associated control valve to its first and second positions, respectively; a two-position, solenoid-operated, pilot valve associated with each control valve providing communication between the source and first servo means of the associated control valve when in the first position and between the first servo means of the associated control valve and the reservoir when in the second position; and a two-position, solenoid-operated, reset valve providing communication between the source and the second servo means associated with each control valve when in a first position and between the second servo means and the reservoir when in a second position.
Claim 13
Dependent Claim
37 words
A control system as set forth in claim 8 wherein each control valve includes detent means for holding the control valve in the first and second positions in the absence of fluid pressure in the servo means.
Claim 14
Dependent Claim
40 words
A control system as set forth in claim 9 wherein the pilot valves and reset valves are each biased to the second position, each includes a solenoid, and each is moved to its first position upon energization of its solenoid.
Claim 15
Dependent Claim
33 words
A control system as set forth in claim 10 wherein the servo means are subjected to the same fluid pressure as the hydraulic functions when their respective valves are in the first positions.
Claim 16
Dependent Claim
40 words
A control system as set forth in claim 10 wherein the servo means are subjected to a fluid pressure less than the fluid pressure to which the hydraulic functions are subjected when their respective valves are in the first positions.
References Cited (Backward Citations)
US2732860A
Cited
US2775982A
Cited
US3026892A
Cited
US3155365A
Cited
US3283784A
Cited
US3491982A
Cited
US3556154A
Cited
US3512453A
Cited
US3598148A
Cited
DE2038661A1
Cited
US3750705A
Cited
US3817153A
Cited
US3735781A
Cited
US3827668A
Cited
DE2360530A1
Cited
US4014509A
Cited
US4046165A
Cited
US4194719A
Cited
US4212165A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-01-26 | 1990-07-28 | 1991-01-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-01-26 | 1994-07-28 | 1995-01-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-01-26 | 1998-07-28 | 1999-01-27 | $7700.00 | Window Closed / Lapsed |