US3854780A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multi-stage brake valve
Assignee: McDonnell Douglas Corp
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Filing: 1973-06-08
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Granted: 1974-12-17
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Expires: 1993-06-08
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
- 👤 W Boehringer
- 👤 J 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; Y10S; Y10S303/00; Y10S303/90; Y10T; Y10T137/00; Y10T137/2496; Y10T137/2559; Y10T137/2562
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
236 words
A valve for controlling the operation of at least one hydraulic brake actuator, said valve including: a connection to a source of pressurized hydraulic fluid; a connection to a return of hydraulic fluid; an output connection for conducting hydraulic fluid to and from said brake actuator; 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 fed thereto to predeterminately conduct the pressurized hydraulic fluid from said source connection to said output connection, to predeterminately conduct the pressurized hydraulic fluid from said output connection to said return connection, and to predeterminately block flow of the hydraulic fluid between said output connection and said source and return connection; flow restrictor means connected between said first valve stage and said output connection to the brake actuator to generate differential pressures thereacross when said first valve stage is conducting flow of pressurized hydraulic fluid 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 the differential pressures generated by said flow restrictor means and responsive thereto to augment the flow of pressurized hydraulic fluid from said first valve stage when a predetermined differential pressure in present across said flow restrictor means.
Claim 2
Dependent Claim
236 words
A valve for controlling the operation of at least one hydraulic brake actuator, said valve including: a connection to a source of pressurized hydraulic fluid; a connection to a return of hydraulic fluid; an output connection for conducting hydraulic fluid to and from said brake actuator; 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 fed thereto to predeterminately conduct the pressurized hydraulic fluid from said source connection to said output connection, to predeterminately conduct the pressurized hydraulic fluid from said output connection to said return connection, and to predeterminately block flow of the hydraulic fluid between said output connection and said source and return connection; flow restrictor means connected between said first valve stage and said output connection to the brake actuator to generate differential pressures thereacross when said first valve stage is conducting flow of pressurized hydraulic fluid 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 the differential pressures generated by said flow restrictor means and responsive thereto to augment the flow of pressurized hydraulic fluid from said first valve stage when a predetermined differential pressure in present across said flow restrictor means.
Claim 3
Dependent Claim
181 words
The valve defined in claim 1 wherein said second valve stage includes: a pressure port connected to said connectioN to a source of pressurized hydraulic fluid; a return port connected to said connection to a return of hydraulic fluid; an output port connected to said output connection; a second stage valve spool located in said valve for controlling flow of hydraulic fluid between said pressure port and said output port and between said output port and said return port; and bias means for biasing said second stage valve spool in a predetermined position which prevents hydraulic flow between the ports, said second stage valve spool also having first and second end portions each in communication with an opposite side of said differential pressures generated by said flow restrictor means whereby predetermined differential pressures are capable of overcoming the bias of said bias means on said second stage valve spool to move said second stage valve spool to positions which allow flow of hydraulic fluid from said pressure port to said output port and from said output port to said return port.
Claim 4
Dependent Claim
105 words
The valve defined in claim 2 wherein said second stage bias means include: a first spring acting to urge said second stage valve spool from a position allowing flow from said pressure port to said output port to the predetermined position allowing no flow; a second spring acting to urge said second stage valve spool from a position allowing flow from said output port to said return port to the predetermined position allowing no flow, whereby said first and second springs are sized to be overpowered by predetermined differential pressures generated by said flow restrictor means to move said spool to the flow allowing positions.
Claim 5
Dependent Claim
58 words
The valve defined in claim 3 wherein said first spring is a preloaded spring and wherein said first end portion of said second stage valve spool has a greater area exposed to pressure than said second end portion, whereby the pressures at said end portions generate force which assists in overcoming the preload of said first preloaded spring.
Claim 6
Dependent Claim
231 words
The valve defined in claim 1 wherein said second valve stage includes: a pressure port connected to said connection to a source of pressurized hydraulic fluid; a return port connected to said connection to a return of hydraulic fluid; an output port connected to said output connection; a second stage valve spool located in said valve for controlling flow of hydraulic fluid between said pressure port and said output port and between said output port and said return port; first bias means to urge said second stage valve spool from positions allowing flow from said pressure port to said output port to a position allowing no flow; and second bias means to urge said spool from the position allowing no flow to positions allowing flow from said output port to said return port, said second bias means being weaker than said first bias means, said second stage valve spool also having a first end portion in communication with pressure on one side of said flow restrictor means, and a second opposite end portion in communication with pressure on the opposite side of said flow restrictor means whereby predetermined pressures acting differentially on said first and second end portions are capable of overcoming said first and second bias means to move said second stage valve spool to a position allowing flow of hydraulic fluid from said pressure port to said output port.
Claim 7
Dependent Claim
146 words
The valve defined in claim 5 wherein said second stage valve spool first end portion has a greater area exposed to pressure than said second stage valve spool second end portion and wherein said flow restrictor means is a one-way restrictor which produces relatively little differential pressure thereacross when flow is from the actuator to the return of hydraulic fluid, said second bias means being sized to be overcome by the force generated by a predetermined pressure acting on the different exposed areas of said first and second end portions so that when the pressure applied to the actuator is reduceD below the predetermined pressure, said second bias means are no longer overcome and said second bias means move said spool to a position to allow flow from said output port to said return port thereby relieving any pressure in the actuator to prevent dragging brakes.
Claim 8
Dependent Claim
66 words
The valve defined in claim 1 wherein said flow restrictor means include means for generating reverse differential pressure when said first valve stage is conducting a flow of hydraulic fluid 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 hydraulic flow between said output connection and said return connection.
Claim 9
Dependent Claim
208 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 hydraulic fluid, said spool having first and second opposite end portions, a center portion which blocks flow of pressurized hydraulic fluid through said second valve stage and first and second positions on opposite sides of said center position which enables 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 flow restrictor means to said first end portion of said second stage valve spool; means to communicate the pressure on the other side of said flow restrictor 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 flow restrictor 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 hydraulic fluid between said first valve stage and said output connection to the brake actuator.
Claim 10
Dependent Claim
67 words
The valve defined in claim 8 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 11
Dependent Claim
45 words
The valve defined in claim 8 wherein said first end portion of said second stage valve spool has a greater area than said second end portion so that the pressures applied to said end portions tend to move said spool toward said second end portion.
Claim 12
Dependent Claim
108 words
The valve defined in claim 10 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 low augmentation.
Claim 13
Dependent Claim
39 words
The valve defined in claim 11 wherein said flow restrictor means include means which generate substantially no differential pressure when said first valve stage is conducting a flow of hydraulic fluid between said output connection and said return connection.
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 |