Patent US3791775A successfully refreshed from Google Patents.
US3791775A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydraulic fluid supply apparatus for a hydraulic servomechanism
Assignee: RTX Corp
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Filing: 1972-06-19
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Granted: 1974-02-12
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Expires: 1992-06-19
Abstract
Abstract Under normal operating conditions a primary pump and a primary reservoir comprise the hydraulic fluid supply apparatus for each of two stages of a hydraulic servomechanism. A transfer valve is responsive to the difference of the hydraulic fluid pressures of each primary pump and an auxiliary pump. A failure which causes a reduction in the pressure provided by either or both primary pumps causes the connection of the auxiliary pump and an auxiliary reservoir to the respective stage.
Inventors
- 👤 G Bochnak
- 👤 Lennan R Mac
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 18:27
CPC Classifications
F; F15; F15B; F15B11/00; F15B11/16; F15B11/17; F15B2211/00; F15B2211/20; F15B2211/205; F15B2211/20576; F15B2211/20584; F15B2211/30; F15B2211/305; F15B2211/3056; F15B2211/3059; F15B2211/30595; F15B2211/315; F15B2211/3157; F15B2211/31582; F15B2211/40; F15B2211/405; F15B2211/40523; F15B2211/4053; F15B2211/70; F15B2211/71; F15B2211/7142; F15B2211/78; F15B2211/781; F15B2211/80; F15B2211/875; F15B2211/8757
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
161 words
A hydraulic supply system for maintaining servo power including: a first supply pump and a first reservoir connected to a first stage of a tandem servo, a second supply pump and a second reservoir connected to a second stage of said servo, a first transfer valve between said first supply pump and said servo, and said servo and said first reservoir, a second transfer valve between said second supply pump and said servo, and said servo and said second reservoir, a third pump and a third reservoir connected to said first and second transfer valves, means associated with each transfer valve for connecting its related supply pump and servo stage when supply pump pressure equals or exceeds third pump pressure, and means associated with each transfer valve for connecting said third pump to either or both said first and second servo stages when the supply pressure of either or both said related first and second pumps drops below a preselected pressure.
Claim 2
Dependent Claim
161 words
A hydraulic supply system for maintaining servo power including: a first supply pump and a first reservoir connected to a first stage of a tandem servo, a second supply pump and a second reservoir connected to a second stage of said servo, a first transfer valve between said first supply pump and said servo, and said servo and said first reservoir, a second transfer valve between said second supply pump and said servo, and said servo and said second reservoir, a third pump and a third reservoir connected to said first and second transfer valves, means associated with each transfer valve for connecting its related supply pump and servo stage when supply pump pressure equals or exceeds third pump pressure, and means associated with each transfer valve for connecting said third pump to either or both said first and second servo stages when the supply pressure of either or both said related first and second pumps drops below a preselected pressure.
Claim 3
Dependent Claim
45 words
A hydraulic supply system in accordance with claim 1 in which each transfer valve includes a spool valve subject to pressure from said third pump and one of said supply pumps and controlling the admission of pump pressure to one stage of said tandem servo.
Claim 4
Dependent Claim
30 words
A hydraulic supply system in accordance with claim 1 in which each pump and associated reservoir comprises a supply system completely isolated from other pump and associated reservoir supply systems.
Claim 5
Dependent Claim
208 words
A hydraulic supply system for maintaining servo power including: a first supply pump and a first reservoir connected to a first stage of a tandem servo, a second supply pump and a second reservoir connected to a second stage of said servo, a first transfer valve between said first supply pump and said servo, and said servo and said first reservoir, a second transfer valve between said second supply pump and said servo, and said servo and said second reservoir, a third pump and a third reservoir connected to said first and second transfer valves, means in said first transfer valve for connecting said first supply pump to said servo first stage when said first supply pump pressure exceeds said third pump pressure; means in said first transfer valve for connecting said third pump to said servo first stage when said first supply pump pressure decreases below said third pump pressure; means in said second transfer valve for connecting said second supply pump to said servo second stage when said second supply pump pressure exceeds said third pump pressure; and means in said second transfer valve for connecting said third pump to said servo second stage when said second supply pump pressure decreases below said third pump pressure.
Claim 6
Dependent Claim
208 words
A hydraulic supply system for maintaining servo power including: a first supply pump and a first reservoir connected to a first stage of a tandem servo, a second supply pump and a second reservoir connected to a second stage of said servo, a first transfer valve between said first supply pump and said servo, and said servo and said first reservoir, a second transfer valve between said second supply pump and said servo, and said servo and said second reservoir, a third pump and a third reservoir connected to said first and second transfer valves, means in said first transfer valve for connecting said first supply pump to said servo first stage when said first supply pump pressure exceeds said third pump pressure; means in said first transfer valve for connecting said third pump to said servo first stage when said first supply pump pressure decreases below said third pump pressure; means in said second transfer valve for connecting said second supply pump to said servo second stage when said second supply pump pressure exceeds said third pump pressure; and means in said second transfer valve for connecting said third pump to said servo second stage when said second supply pump pressure decreases below said third pump pressure.
Claim 7
Dependent Claim
24 words
A hydraulic supply system in accordance with claim 4 in which the means in said first and second transfer valves is a spool valve.
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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) | 1977-02-11 | 1977-08-13 | 1978-02-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-11 | 1981-08-13 | 1982-02-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-11 | 1985-08-13 | 1986-02-12 | $7700.00 | Window Closed / Lapsed |