Patent US3680312A successfully refreshed from Google Patents.
US3680312A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydrostatic machine
Assignee: Linde GmbH
•
Filing: 1970-10-09
•
Granted: 1972-08-01
•
Expires: 1990-10-09
Abstract
Abstract A hydrostatic machine, e.g. a hydrostatic pump or hydrostatic motor operating in a closed fluid circuit and having a housing into which leakage of the hydraulic medium can occur, is provided with check valves communicating between the housing and the main ports to enable leakage fluid to pass directly into the main hydraulic circuit.
Inventors
- 👤 Franz Forster
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 16:59
CPC Classifications
F; F16; F16H; F16H61/00; F16H61/38; F16H61/40; F04; F04B; F04B1/00; F04B1/12; F04B1/20; F04B1/2014; F04B1/2064; F16H39/00; F16H39/04; F16H39/06; F16H39/08; F16H39/10; F16H39/14; Y; Y10; Y10S; Y10S60/00; Y10S60/912
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
115 words
A hydraulic system comprising a hydrostatic pump and a hydrostatic motor constituting hydrostatic machines; means connecting said machines in a closed fluid-circulating path and including a high-pressure passage and a low-pressure passage; a pressure-retentive housing surrounding at least one of said machines and forming a chamber maintainable at an elevated pressure corresponding substantially to that of said low-pressure passage; and a duct wholly within said housing constituting the sole leakage-fluid path therefrom and connecting said lowpressure passage with said chamber, and a check valve in said duct for unidirectional flow of fluid between said chamber and said low-pressure passage and blocking reverse flow of fluid through said duct between said low-pressure passage and said chamber.
Claim 2
Dependent Claim
115 words
A hydraulic system comprising a hydrostatic pump and a hydrostatic motor constituting hydrostatic machines; means connecting said machines in a closed fluid-circulating path and including a high-pressure passage and a low-pressure passage; a pressure-retentive housing surrounding at least one of said machines and forming a chamber maintainable at an elevated pressure corresponding substantially to that of said low-pressure passage; and a duct wholly within said housing constituting the sole leakage-fluid path therefrom and connecting said lowpressure passage with said chamber, and a check valve in said duct for unidirectional flow of fluid between said chamber and said low-pressure passage and blocking reverse flow of fluid through said duct between said low-pressure passage and said chamber.
Claim 3
Dependent Claim
38 words
The hydraulic system defined in claim 1 wherein a respective duct connects each of said passages with said chamber and is provided with a respective check valve permitting unidirectional flow of fluid from the chamber into said passages.
Claim 4
Dependent Claim
22 words
The hydraulic system defined in claim 1, further comprising distributing valve means for selectively connecting said duct with one of said passages.
Claim 5
Dependent Claim
20 words
The hydraulic system defined in claim 1, further comprising a feed pump connected with said chamber for circulating fluid therethrough.
Claim 6
Dependent Claim
20 words
The hydraulic system defined in claim 4, further comprising a heat-dissipating cooler in a hydraulic circuit with said feed pump.
Claim 7
Dependent Claim
16 words
The hydraulic system defined in claim 1 wherein both said machines are provided within said housing.
Claim 8
Dependent Claim
23 words
The hydraulic system defined in claim 1, further comprising a hydropneumatic accumulator connected to said chamber for maintaining a predetermined pressure level therein.
Claim 9
Dependent Claim
27 words
The hydraulic system defined in claim 1, further comprising means for maintaining the pressure within said chamber at a level of substantially 6 to 8 atmospheres gauge.
Claim 10
Dependent Claim
22 words
The hydraulic system defined in claim 1 wherein said housing encloses a pair of hydrostatic pumps, coupled together in a double-pump aggregate.
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) | 1975-08-01 | 1976-01-31 | 1976-08-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-01 | 1980-01-31 | 1980-08-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-01 | 1984-01-31 | 1984-08-01 | $7700.00 | Window Closed / Lapsed |