Patent US3811281A successfully refreshed from Google Patents.
US3811281A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydraulic engine starting systems
Assignee: Northrop Grumman Properties Ltd
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Filing: 1972-07-12
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Granted: 1974-05-21
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Expires: 1992-07-12
Abstract
Abstract An hydraulic engine starting system includes a motor which is used both for engine starting and for driving a pump for charging accumulators for storing liquid under pressure. For engine starting the motor is connected to one accumulator to receive liquid therefrom. For charging the accumulators the motor is connected to an hydraulic circuit powered by the engine and a clutch connects the motor to the pump. The clutch is operated by pressure in the circuit so that it is disengaged during engine starting. The motor has a constant flow servo-system which has means for varying the displacement of the motor according to whether the motor is receiving liquid from the accumulator or the circuit.
Inventors
- 👤 E Williams
- 👤 J Wise
- 👤 R Wellings
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 08:50
CPC Classifications
F; F02; F02N; F02N15/00
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
120 words
An hydraulic engine starting system comprising an accumulator, a pump for charging the accumulator, and connected thereto by a non-return valve, a clutch for drivingly connecting said pump to a prime mover when charging of the accumulator is required, an engine starting motor and valve means controlling the connection of said engine starting motor to said accumulator so that on actuation of said valve means liquid is discharged from the accumulator into the motor, said clutch being fluidpressure actuated and being connected to an hydraulic circuit associated with the engine such that hydraulic pressure is normally present in said circuit when the engine is running, said cLutch being disengaged when the pressure in said circuit is below a predetermined value.
Claim 2
Dependent Claim
120 words
An hydraulic engine starting system comprising an accumulator, a pump for charging the accumulator, and connected thereto by a non-return valve, a clutch for drivingly connecting said pump to a prime mover when charging of the accumulator is required, an engine starting motor and valve means controlling the connection of said engine starting motor to said accumulator so that on actuation of said valve means liquid is discharged from the accumulator into the motor, said clutch being fluidpressure actuated and being connected to an hydraulic circuit associated with the engine such that hydraulic pressure is normally present in said circuit when the engine is running, said cLutch being disengaged when the pressure in said circuit is below a predetermined value.
Claim 3
Dependent Claim
30 words
A system as claimed in claim 1 in which said clutch is connected to said motor so that the pump is driven by the motor when the clutch is engaged.
Claim 4
Dependent Claim
62 words
A system as claimed in claim 2 in which the motor has a constant flow servo-control for varying the displacement of the motor, said servo-control comprising means for producing a signal pressure varying with the rate of flow of liquid through the motor, and a pressure sensitive displacement control device for decreasing the displacement of the motor as the flow rate increases.
Claim 5
Dependent Claim
47 words
A system as claimed in claim 3 wherein, said pressure sensitive displacement control device includes biasing means sensitive to the pressure in said hydraulic circuit so as to decrease the displacement of the motor for a given flow rate when pressure is present in said hydraulic circuit.
Claim 6
Dependent Claim
25 words
A system as claimed in claim 4 in which means are provided for increasing the maximum displacement of the motor when the clutch is engaged.
Claim 7
Dependent Claim
39 words
A system as claimed in claim 3 in which there is provided temperature sensitive means controlling the position of a maximum displacement stop in the motor whereby maximum displacement of the motor is decreased as the ambient temperature rises.
Claim 8
Dependent Claim
37 words
A system as claimed in claim 1 in which there are a pair of accumulators connected by non-return valves to the outlet of the pump and a selector valve for selectively connecting said accumulators to the motor.
Claim 9
Dependent Claim
15 words
A system as claimed in claim 7 in which the selector valve is pilot operated.
Claim 10
Dependent Claim
37 words
A system as claimed in claim 1 further comprising an auxiliary pump for charging the accumulator, said auxiliary pump having automatic displacement control means for reducing the auxiliary pump displacement as the auxiliary pump output pressure rises.
Claim 11
Dependent Claim
46 words
A system as claimed in claim 9 in which the auxiliary pump is of the radial piston type including a cam ring spring-loaded to a position of maximum eccentricity and movable in a direction to decrease its eccentricity by the loads applied thereto by the pistons.
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) | 1977-05-20 | 1977-11-19 | 1978-05-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-20 | 1981-11-19 | 1982-05-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-20 | 1985-11-19 | 1986-05-21 | $7700.00 | Window Closed / Lapsed |