US3695710A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydraulic lift controls
Assignee: Individual
•
Filing: 1970-09-22
•
Granted: 1972-10-03
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Expires: 1990-09-22
Abstract
Abstract A control apparatus for hydraulic lifts of the type associated with elevating mechanism for vehicle bodies or dump trucks. Fluid under pressure is supplied to the hydraulic cylinder only when the gear shift lever of the transmission is in neutral position and the brakes of the vehicle have been applied. An electric clutch is interposed between the transmission power take-off and the pump which supplies fluid to the lift cylinder and this clutch is actuated only when the gear shift lever is in neutral position.
Inventors
- 👤 Paul A Cresci
- 👤 Thomas H Paris
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 21:18
CPC Classifications
B; B60; B60P; B60P1/00; B60P1/04; B60P1/16; B60P1/162; Y; Y10; Y10S; Y10S60/00; Y10S60/911
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
121 words
In combination with a hydraulic lift mechanism for vehicle bodies including a cylinder and piston, a change speed transmission provided with a power take-off shaft, a gear shift lever for changing engagement of gears in said transmission and having a neutral position, a reservoir for fluid, a pump for supplying fluid under pressure from said reservoir to said cylinder, an electric clutch interposed between said power takeoff shaft and said pump, a source of electrical energy for energizing said clutch to connect said shaft to said pump, and a switch controlling the supply of electrical energy to said clutch, said switch being associated with said gear shift lever and being closed only when said gear shift lever is in neutral position.
Claim 2
Dependent Claim
121 words
In combination with a hydraulic lift mechanism for vehicle bodies including a cylinder and piston, a change speed transmission provided with a power take-off shaft, a gear shift lever for changing engagement of gears in said transmission and having a neutral position, a reservoir for fluid, a pump for supplying fluid under pressure from said reservoir to said cylinder, an electric clutch interposed between said power takeoff shaft and said pump, a source of electrical energy for energizing said clutch to connect said shaft to said pump, and a switch controlling the supply of electrical energy to said clutch, said switch being associated with said gear shift lever and being closed only when said gear shift lever is in neutral position.
Claim 3
Dependent Claim
20 words
The combination defined in claim 1, in which means are provided for locking said gear shift lever in neutral position.
Claim 4
Dependent Claim
57 words
The combination defined in claim 1, in which a by-pass conducts fluid from said pump to said reservoir, said by-pass being interposed between said pump and said cylinder, a normally open solenoid valve in said by-pass, and a switch for energizing said solenoid valve to close said by-pass whereby fluid under pressure is supplied to said cylinder.
Claim 5
Dependent Claim
61 words
The combination defined in claim 3, in which a conduit returns fluid from said cylinder to said reservoir, a normally closed solenoid valve in said conduit, the switch for controlling said valve in said by-pass being adjustable to interrupt the supply of electrical energy to said normally open valve and to energize said normally closed valve to open said return conduit.
Claim 6
Dependent Claim
17 words
The combination defined in claim 4, in which said return conduit is provided with flow restricting means.
Claim 7
Dependent Claim
55 words
The combination defined in claim 1 in which a by-pass conducts fluid from said pump to said reservoir, said by-pass being interposed between said pump and said cylinder, and a pressure responsive valve in said by-pass, said last mentioned valve opening said by-pass when the pressure of fluid in said cylinder exceeds a predetermined limit.
Claim 8
Dependent Claim
47 words
The combination defined in claim 1 in which the vehicle is provided with brake means, a second switch in series with the switch for energizing said clutch, said second switch being responsive to brake application pressure and being closed upon application of pressure to said brake means.
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) | 1975-10-03 | 1976-04-03 | 1976-10-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-03 | 1980-04-03 | 1980-10-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-03 | 1984-04-03 | 1984-10-03 | $7700.00 | Window Closed / Lapsed |