US3916933A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multi-stage valve
Assignee: McDonnell Douglas Corp
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Filing: 1971-08-11
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Granted: 1975-11-04
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Expires: 1991-08-11
Abstract
Abstract A multi-stage, three port valve in which input commands are fed to a first stage which normally modulates the flow of medium to an actuator. During high demand conditions, differential pressures generated within the valve cause one or more other stages of the valve to automatically supplement medium flow as required.
Inventors
- 👤 Wilfred E Boehringer
- 👤 James V Walker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 19:51
CPC Classifications
B; B60; B60T; B60T8/00; B60T8/32; B60T8/321; B60T8/325; B60T13/00; B60T13/10; B60T13/12; B60T8/34; B60T8/36; Y; Y10; Y10T; Y10T137/00; Y10T137/2496; Y10T137/2544; Y10T137/2559; Y10T137/2574; Y10T137/2605; Y10T137/2617
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
234 words
A valve for controlling the flow of medium to a reservoir and from a source of pressurized medium to operate actuator means, said valve including: a source connection for conducting medium from the source of pressurized medium; a return connection for conducting medium back to the reservoir an output connection for conducting medium to and from the actuator means; a first valve stage in communication with said source connection, said return connection and said output connection, said first valve stage including means to feed inputs thereto and means responsive to the inputs to predeterminately conduct pressurized medium flow from said source connection to said output connection, to predeterminately conduct pressurized medium flow from said output connection to said return connection, and to predeterminately block flow of medium between said output connection and said source and return connections; differential pressure generating means connected between said first valve stage and said output connection to generate differential pressures thereacross when said first valve stage is conducting a flow of pressurized medium between said source connection and said output connection; and a second valve stage in communication with said source connection, said return connection and said output connection, said second valve stage including means in communication with said differential pressures and responsive thereto to augment the flow of pressurized medium from said first valve stage when a predetermined differential pressure is present across said Differential pressure generating means.
Claim 2
Dependent Claim
234 words
A valve for controlling the flow of medium to a reservoir and from a source of pressurized medium to operate actuator means, said valve including: a source connection for conducting medium from the source of pressurized medium; a return connection for conducting medium back to the reservoir an output connection for conducting medium to and from the actuator means; a first valve stage in communication with said source connection, said return connection and said output connection, said first valve stage including means to feed inputs thereto and means responsive to the inputs to predeterminately conduct pressurized medium flow from said source connection to said output connection, to predeterminately conduct pressurized medium flow from said output connection to said return connection, and to predeterminately block flow of medium between said output connection and said source and return connections; differential pressure generating means connected between said first valve stage and said output connection to generate differential pressures thereacross when said first valve stage is conducting a flow of pressurized medium between said source connection and said output connection; and a second valve stage in communication with said source connection, said return connection and said output connection, said second valve stage including means in communication with said differential pressures and responsive thereto to augment the flow of pressurized medium from said first valve stage when a predetermined differential pressure is present across said Differential pressure generating means.
Claim 3
Dependent Claim
65 words
The valve defined in claim 1 wherein said differential pressure generating means include means for generating reverse differential pressure when said first valve stage is conducting a flow of medium from said output connection to said return connection, said second valve stage including means responsive to a predetermined reverse differential pressure to augment the flow of medium between said output connection and said return connection.
Claim 4
Dependent Claim
205 words
The valve defined in claim 1 wherein said second valve stage includes: a second valve stage housing; a second stage valve spool within said second valve stage housing for controlling the augmenting flow of pressurized medium, said spool having first and second opposite end portions, a center position which blocks flow of pressurized medium through said second valve stage and first and second positions on opposite sides of said center position which enable flow from said source connection to said output connection and from said output connection to said return connection respectively; means to communicate the pressure on one side of said differential pressure generating means to said first end portion of said second stage valve spool; means to communicate the pressure on the other side of said differential pressure generating means to said second end portion of said second stage valve spool; and resilient means to bias said second stage valve spool to a predetermined position, whereby said predetermined differential pressure from said differential pressure generating means acting on said end portions of said second stage valve spool moves said spool against said resilient means to a position to augment the flow of pressurized medium between said first valve stage and said output connection.
Claim 5
Dependent Claim
67 words
The valve defined in claim 3 wherein said resilient means include: a first spring acting against said second stage spool to urge said spool toward said second spool position to said center position; and a second spring which is lighter than said first spring acting against said second stage spool to urge said spool toward said first spool position to said center position which prevents flow augmentation.
Claim 6
Dependent Claim
44 words
The valve defined in claim 3 wherein said first end portion of said second stage valve spool has a greater area than said second end portion so that pressure applied to said end portions tends to move said spool toward said second end portion.
Claim 7
Dependent Claim
108 words
The valve defined in claim 5 wherein said resilient means include: a first preloaded spring acting against said second stage spool to urge said spool toward said second spool position to said center position; and a second preloaded spring which is lighter than said first preloaded spring acting against said second stage spool to urge said spool toward said second position to allow flow augmentation between said output connection and said return connection, whereby a relatively small predetermined pressure acting on said second spool end portions is capable of overpowering said second preloaded spring and moving said second stage spool to said center position which prevents flow augmentation.
Claim 8
Dependent Claim
39 words
The valve defined in claim 6 wherein said differential pressure generating means include means which generate substantially no differential pressure when said first valve stage is conducting a flow of medium between said output connection and said return connection.
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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) | 1978-11-03 | 1979-05-05 | 1979-11-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-03 | 1983-05-05 | 1983-11-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-03 | 1987-05-05 | 1987-11-04 | $7700.00 | Window Closed / Lapsed |