US3854847A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for damping the pressure increase of hydrostatic drives
Assignee: Putzmeister Interholding GmbH
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Filing: 1973-02-20
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Granted: 1974-12-17
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Expires: 1993-02-20
Abstract
Abstract An apparatus for damping the pressure increase of hydrostatic drives, especially axial piston pumps, with swash plate control and pre-biased oil circulation, wherein the pressurized oil compartment of an adjustment cylinder is connected with the lower pressure side of the oil infeed of the pump via a check or nonreturn valve which opens in the direction of the low pressure conduit of the oil infeed.
Inventors
- 👤 K Schlecht
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 10:04
CPC Classifications
F; F16; F16H; F16H61/00; F16H61/38; F16H61/40; F16H61/42; F16H61/433; F04; F04B; F04B49/00; F04B49/002; F16H61/4183; F16H61/46; F16H61/465
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
142 words
An apparatus for damping the pressure increase of hydrostatic drives, especially axial piston pumps with swash plate control and pre-biased oil circulation system, the improvement comprising an adjustment cylinder having a pressurized oil compartment, a pump, an oil infeed means including an oil infeed line for the pump, a check valve, the pressurized oil compartment of the adjustment cylinder being flow connected with the low pressure side of the oil infeed line of the pump via the check valve, said check valve opening in the direction of the low pressurE infeed line, an internal hydraulic servo-adjustment means, said adjustment cylinder defining an external adjustment cylinder, an internal adjustment cylinder, said servo-adjustment means incorporating an external adjustment lever hingedly connected with the external adjustment cylinder, and a further check valve for flow connecting the internal adjustment cylinder with the low pressure infeed line.
Claim 2
Independent Claim
142 words
An apparatus for damping the pressure increase of hydrostatic drives, especially axial piston pumps with swash plate control and pre-biased oil circulation system, the improvement comprising an adjustment cylinder having a pressurized oil compartment, a pump, an oil infeed means including an oil infeed line for the pump, a check valve, the pressurized oil compartment of the adjustment cylinder being flow connected with the low pressure side of the oil infeed line of the pump via the check valve, said check valve opening in the direction of the low pressurE infeed line, an internal hydraulic servo-adjustment means, said adjustment cylinder defining an external adjustment cylinder, an internal adjustment cylinder, said servo-adjustment means incorporating an external adjustment lever hingedly connected with the external adjustment cylinder, and a further check valve for flow connecting the internal adjustment cylinder with the low pressure infeed line.
Claim 3
Dependent Claim
44 words
The apparatus as defined in claim 1, wherein the external adjustment cylinder is equipped with a spring, the restoring force of which corresponds to a pressure which is only slightly less than the pressure prevailing at the low pressure infeed line of the pump.
Claim 4
Dependent Claim
36 words
The apparatus as defined in claim 2, further including an external auxiliary pump for supplying both the external adjustment as well as also via the check valve the low pressure infeed line and the servo-adjustment means.
Claim 5
Dependent Claim
22 words
The apparatus as defined in claim 1, further including a check valve means for connecting the servo-adjustment means with the auxiliary pump.
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) | 1977-12-16 | 1978-06-17 | 1978-12-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-16 | 1982-06-17 | 1982-12-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-16 | 1986-06-17 | 1986-12-17 | $7700.00 | Window Closed / Lapsed |