US5313795A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Control system with tri-pressure selector network
Assignee: CNH Industrial America LLC
•
Filing: 1992-12-17
•
Granted: 1994-05-24
•
Expires: 2012-12-17
Abstract
Abstract The invention is an improvement in a control system having first, second and third sources of fluid at differing pressures. The improvement comprises a tripath pressure selector network connected to the first and second sources. A pressure-sensing device connects the network and the third source when the third source is at a predetermined minimum pressure. The invention has particular utility in mobile construction machinery having, e.g., steering, implement and brake hydraulic circuits, at differing pressures. In one embodiment, the third source is a brake hydraulic circuit. The improvement helps assure that adequate pilot pressure is available for a "downstream" pilot control valve.
Inventors
- 👤 Donnell L. Dunn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 14:39
CPC Classifications
E; E02; E02F; E02F9/00; E02F9/20; E02F9/22; E02F9/2217; E02F9/2278; E02F9/2292; F; F15; F15B; F15B11/00; F15B11/16; F15B11/17; F15B2211/00; F15B2211/20; F15B2211/205; F15B2211/2053; F15B2211/20538; F15B2211/20576; F15B2211/21; F15B2211/212; F15B2211/50; F15B2211/575; F15B2211/60; F15B2211/635; F15B2211/6355; F15B2211/70; F15B2211/71; F15B2211/7142; F15B2211/78; F15B2211/781
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
66 words
In a control system having first, second and third sources of fluid at differing pressures, the improvement comprising: a tri-path pressure selector network connected to the first and second sources; and wherein: the third source includes first and second accumulators; and, a pressure-sensing device connects the network and the third source only when the second accumulator is at a pressure in excess of about 600 p.s.i.
Claim 2
Dependent Claim
66 words
In a control system having first, second and third sources of fluid at differing pressures, the improvement comprising: a tri-path pressure selector network connected to the first and second sources; and wherein: the third source includes first and second accumulators; and, a pressure-sensing device connects the network and the third source only when the second accumulator is at a pressure in excess of about 600 p.s.i.
Claim 3
Dependent Claim
59 words
In a control system having first, second and third sources of fluid at differing pressures, the improvement wherein: a tri-path pressure selector network is connected to the first and second sources; the third source includes first and second accumulators; and, a pressure-sensing device connects the network and the second accumulator when the second accumulator is at a predetermined pressure.
Claim 4
Dependent Claim
59 words
In a control system having first, second and third sources of fluid at differing pressures, the improvement wherein: a tri-path pressure selector network is connected to the first and second sources; the third source includes first and second accumulators; and, a pressure-sensing device connects the network and the second accumulator when the second accumulator is at a predetermined pressure.
Claim 5
Dependent Claim
129 words
In a control system having first, second and third sources of fluid at differing pressures, the improvement comprising: a tri-path pressure selector network connected to the first and second sources; the third source and the pressure selector network are connected by a pressure line; a check valve is in the pressure line for preventing fluid from the first and second sources from flowing to the third source; a pressure-sensing sequence valve has a pilot signal line connected to the pressure line; the sequence valve connects the third source to the network when the third source is at a predetermined minimum pressure; the check valve is interposed between the pressure-sensing device and the third source; and, the pilot signal line is connected between the sequence valve and the check valve.
Claim 6
Dependent Claim
129 words
In a control system having first, second and third sources of fluid at differing pressures, the improvement comprising: a tri-path pressure selector network connected to the first and second sources; the third source and the pressure selector network are connected by a pressure line; a check valve is in the pressure line for preventing fluid from the first and second sources from flowing to the third source; a pressure-sensing sequence valve has a pilot signal line connected to the pressure line; the sequence valve connects the third source to the network when the third source is at a predetermined minimum pressure; the check valve is interposed between the pressure-sensing device and the third source; and, the pilot signal line is connected between the sequence valve and the check valve.
Claim 7
Dependent Claim
129 words
In a control system having first, second and third sources of fluid at differing pressures, the improvement comprising: a tri-path pressure selector network connected to the first and second sources; the third source and the pressure selector network are connected by a pressure line; a check valve is in the pressure line for preventing fluid from the first and second sources from flowing to the third source; a pressure-sensing sequence valve has a pilot signal line connected to the pressure line; the sequence valve connects the third source to the network when the third source is at a predetermined minimum pressure; the check valve is interposed between the pressure-sensing device and the third source; and, the pilot signal line is connected between the check valve and the third source.
Claim 8
Dependent Claim
129 words
In a control system having first, second and third sources of fluid at differing pressures, the improvement comprising: a tri-path pressure selector network connected to the first and second sources; the third source and the pressure selector network are connected by a pressure line; a check valve is in the pressure line for preventing fluid from the first and second sources from flowing to the third source; a pressure-sensing sequence valve has a pilot signal line connected to the pressure line; the sequence valve connects the third source to the network when the third source is at a predetermined minimum pressure; the check valve is interposed between the pressure-sensing device and the third source; and, the pilot signal line is connected between the check valve and the third source.
References Cited (Backward Citations)
US2309983A
Cited
DE1059768B
Cited
US3129781A
Cited
US3918847A
Cited
US4065228A
Cited
US4473090A
Cited
US4517800A
Cited
US4825659A
Cited
US4633666A
Cited
US4648466A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-05-23 | 1997-11-22 | 1998-05-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-05-23 | 2001-11-22 | 2002-05-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-05-23 | 2005-11-22 | 2006-05-24 | $7700.00 | Window Closed / Lapsed |