US4115033A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Control device for a hydraulic system having at least two pumps
Assignee: Linde GmbH
•
Filing: 1977-01-24
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Granted: 1978-09-19
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Expires: 1997-01-24
Abstract
Abstract A hydraulic system having at least two pumps including a variable-displacement pump and a constant-displacement pump, both driven from a common prime mover, includes a control-pressure pump operated by the shaft of the prime mover and operating with its input a valve which controls the pressure of a control piston acting upon a spring which bears upon the control member in a direction opposite to its setting piston. A cylinder of the setting piston is connected to the output of the adjustable-displacement pump.
Inventors
- 👤 Gustav Kleineisel
- 👤 Dietrich Kuchenbecker
- 👤 Gerd Ahrens
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 03:26
CPC Classifications
F; F04; F04B; F04B49/00; F04B49/007; F04B49/002; F04B49/08
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
210 words
A control device for a hydraulic system comprising at least one first pump having a variable output per revolution as determined by the position of a control member and connected to a first hydraulic network, at least one second pump having a predetermined output per revolution, an energy source having an output shaft connected to said pumps for driving same, and a setting piston shiftable in a respective cylinder and operatively connected to said member for varying the displacement per revolution of said first pump, said control device comprising, in combination: a control line connecting the output side of said first pump with said cylinder; a control-pressure pump connected to said shaft and having an output determined by the speed of said shaft; a spring action on said member in a direction opposite to that at which pressure in said cylinder acts upon said member; a control piston acting upon a seat of said spring for varying the degree to which said spring tends to allow displacement of said control member; a control cylinder slidably receiving said piston; a control valve responsive to the output of said control pressure pump; and means for applying the output of said control pressure pump as controlled by said valve to said control cylinder.
Claim 2
Dependent Claim
210 words
A control device for a hydraulic system comprising at least one first pump having a variable output per revolution as determined by the position of a control member and connected to a first hydraulic network, at least one second pump having a predetermined output per revolution, an energy source having an output shaft connected to said pumps for driving same, and a setting piston shiftable in a respective cylinder and operatively connected to said member for varying the displacement per revolution of said first pump, said control device comprising, in combination: a control line connecting the output side of said first pump with said cylinder; a control-pressure pump connected to said shaft and having an output determined by the speed of said shaft; a spring action on said member in a direction opposite to that at which pressure in said cylinder acts upon said member; a control piston acting upon a seat of said spring for varying the degree to which said spring tends to allow displacement of said control member; a control cylinder slidably receiving said piston; a control valve responsive to the output of said control pressure pump; and means for applying the output of said control pressure pump as controlled by said valve to said control cylinder.
Claim 3
Dependent Claim
19 words
The device defined in claim 1 wherein said control piston acts upon said member in parallel with said spring.
Claim 4
Dependent Claim
45 words
The control device defined in claim 2 wherein said control cylinder is formed in a housing and said spring bears at one side against said housing and at the opposite side against a plate connected to said member, said control piston acting upon said plate.
Claim 5
Dependent Claim
17 words
The device defined in claim 3 wherein said control piston is in force-transmitting relationship with said plate.
Claim 6
Dependent Claim
26 words
The device defined in claim 1 wherein said control piston engages one end of said spring, the other end of said spring bearing against said member.
Claim 7
Dependent Claim
14 words
The device defined in claim 5, further comprising an abutment for said control piston.
Claim 8
Dependent Claim
12 words
The device defined in claim 6, wherein said abutment is selectively adjustable.
Claim 9
Dependent Claim
31 words
The device defined in claim 1, further comprising a first throttle connected between said control pressure pump and said cylinder, and a second throttle connected across the actuators of said valve.
Claim 10
Dependent Claim
19 words
The device defined in claim 8 wherein said throttle is adjustable in response to the settings of said source.
Claim 11
Dependent Claim
33 words
The device defined in claim 1 wherein a plurality of such first pumps are provided and the respective control members of said first pumps are interconnected by a coupling acting upon said spring.
Claim 12
Dependent Claim
18 words
The device defined in claim 10, further comprising means for selectively applying a controllable force to said coupling.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-09-18 | 1982-03-20 | 1982-09-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-09-18 | 1986-03-20 | 1986-09-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-09-18 | 1990-03-20 | 1990-09-19 | $7700.00 | Window Closed / Lapsed |