Patent US3744244A successfully refreshed from Google Patents.
US3744244A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydrostatic drive
Assignee: AUTOMATION EQUIPMENT Inc
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Filing: 1971-07-30
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Granted: 1973-07-10
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Expires: 1991-07-30
Abstract
Abstract A control system for a closed circuit hydrostatic drive including means for positive filtration of fluid replenishing fluid losses in the closed circuit and means for filtering fluid flowing in the closed circuit. The system provides valves for relieving excessive pressure generated within the closed circuit and the replenishment system.
Inventors
- 👤 J Swoager
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 23:21
CPC Classifications
F; F15; F15B; F15B21/00; F15B21/005; F16; F16H; F16H39/00; F16H39/02; F16H61/00; F16H61/38; F16H61/40; F16H61/4078; F16H61/4139
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
165 words
In a closed circuit hydraulic drive including a first pump for supplying fluid under pressure to a motor selectively through first and second conduit means, and a second pump for replenishing fluid to said closed circuit from a source of fluid; a control system comprising: a first filter having an inlet and an outlet, said inlet being connected to the pressure side of said second pump; relief valve means disposed between said second pump and said inlet for returning fluid to said source; a manifold connected to the outlet of said filter for distributing said replenishing fluid to said closed circuit; second and third filters disposed in said first and second conduit means respectively, each of said second and third filters being arranged for fluid passage therethrough; and first and second check valve means disposed in said first and second conduits, respectively, for selectively by-passing each of said second and third filters, and for permitting fluid passage through each of said second and third filters.
Claim 2
Dependent Claim
165 words
In a closed circuit hydraulic drive including a first pump for supplying fluid under pressure to a motor selectively through first and second conduit means, and a second pump for replenishing fluid to said closed circuit from a source of fluid; a control system comprising: a first filter having an inlet and an outlet, said inlet being connected to the pressure side of said second pump; relief valve means disposed between said second pump and said inlet for returning fluid to said source; a manifold connected to the outlet of said filter for distributing said replenishing fluid to said closed circuit; second and third filters disposed in said first and second conduit means respectively, each of said second and third filters being arranged for fluid passage therethrough; and first and second check valve means disposed in said first and second conduits, respectively, for selectively by-passing each of said second and third filters, and for permitting fluid passage through each of said second and third filters.
Claim 3
Dependent Claim
46 words
A control system as recited in claim 1 which includes: a pair of valve means each disposed between said first and second conduit means, respectively, and said pressure side of said second pump for relieving excessive pressure caused by any malfunction of said relief valve means.
Claim 4
Dependent Claim
128 words
In a closed circuit hydraulic drive including a first pump for supplying fluid under pressure to a motor selectively through first and second conduit means, first and second valve means disposed within said motor for relieving high and low pressures within said closed circuit, and a shuttle valve shiftable between a first position and a second position in response to alternations in pressure differential between said first and second conduits, said shuttle valve providing open communication between said first and second conduits, respectively, and said first and second valve means when said shuttle valve in its first and second positions, the improvement comprising: means disposed in the central portion of said shuttle valve for communicating said first and second conduit means with said first and second valve means.
Claim 5
Dependent Claim
128 words
In a closed circuit hydraulic drive including a first pump for supplying fluid under pressure to a motor selectively through first and second conduit means, first and second valve means disposed within said motor for relieving high and low pressures within said closed circuit, and a shuttle valve shiftable between a first position and a second position in response to alternations in pressure differential between said first and second conduits, said shuttle valve providing open communication between said first and second conduits, respectively, and said first and second valve means when said shuttle valve in its first and second positions, the improvement comprising: means disposed in the central portion of said shuttle valve for communicating said first and second conduit means with said first and second valve 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) | 1976-07-09 | 1977-01-08 | 1977-07-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-09 | 1981-01-08 | 1981-07-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-09 | 1985-01-08 | 1985-07-10 | $7700.00 | Window Closed / Lapsed |