US3773367A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fluid pressure braking systems for vehicles
Assignee: Whitnash PLC
•
Filing: 1971-07-20
•
Granted: 1973-11-20
•
Expires: 1991-07-20
Abstract
Abstract A liquid pressure reducing valve for use in a liquid pressure vehicle braking system to reduce the pressure acting to apply the rear wheel brakes in relation to the pressure available at the pressure source of the braking system under heavy braking comprises a valve closed when a predetermined pressure is built up in the braking system and including a plunger through which pressure is transmitted to rear wheel brake operating motor cylinders when the valve is closed, a spring being provided which opposes the source pressure acting on the plunger and so reduces the pressure exerted by the plunger on liquid in the motor cylinders. The liquid pressure acting to close the valve is opposed by resilient means the load of which is varied in accordance with the load supported by the rear wheels of the vehicle.
Inventors
- 👤 D Osborne
- 👤 L Chouings
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 02:53
CPC Classifications
B; B60; B60T; B60T8/00; B60T8/18; B60T8/1812; B60T8/1831; B60T8/1837; B60T8/185
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
286 words
A pressure reducing valve for use in a liquid pressure vehicle braking system to provide a pressure in motor cylinders of said braking system actuating brakes on wheels of the vehicle less than the pressure at a pressure source providing liquid pressure to operate said motor cylinders, said pressure reducing valve comprising a valve body having a valve bore, a first plunger slidable in said valve bore, a second plunger slidable in said valve bore, said second plunger being annular and surrounding said first plunger, an inlet passage opening into said bore on one side of said second plunger, an outlet bore opening into said bore on the other side of said second plunger, passage means in said first plunger providing a connection between opposite sides of said second plunger, a valve closure member on said first plunger co-operating with a seat in the bore to close said passage means, first resilient means acting on said first plunger to urge it in a direction to unseat said valve closure member, and second resilient means acting on said second plunger to oppose thrust exerted thereon by pressure in the inlet passage, the arrangement being such that the pressure in the outlet passage opposes the thrust exerted by the first resilient means on the first plunger and, when said pressure in the outlet passage reaches a predetermined value, moves the first plunger to seat the valve closure member, after which the pressure in the inlet passage acts on the end of the second plunger adjacent that passage to produce a pressure at the outlet passage which is less than the pressure at the inlet passage by an amount depending on the thrust exerted by the second resilient means.
Claim 2
Dependent Claim
286 words
A pressure reducing valve for use in a liquid pressure vehicle braking system to provide a pressure in motor cylinders of said braking system actuating brakes on wheels of the vehicle less than the pressure at a pressure source providing liquid pressure to operate said motor cylinders, said pressure reducing valve comprising a valve body having a valve bore, a first plunger slidable in said valve bore, a second plunger slidable in said valve bore, said second plunger being annular and surrounding said first plunger, an inlet passage opening into said bore on one side of said second plunger, an outlet bore opening into said bore on the other side of said second plunger, passage means in said first plunger providing a connection between opposite sides of said second plunger, a valve closure member on said first plunger co-operating with a seat in the bore to close said passage means, first resilient means acting on said first plunger to urge it in a direction to unseat said valve closure member, and second resilient means acting on said second plunger to oppose thrust exerted thereon by pressure in the inlet passage, the arrangement being such that the pressure in the outlet passage opposes the thrust exerted by the first resilient means on the first plunger and, when said pressure in the outlet passage reaches a predetermined value, moves the first plunger to seat the valve closure member, after which the pressure in the inlet passage acts on the end of the second plunger adjacent that passage to produce a pressure at the outlet passage which is less than the pressure at the inlet passage by an amount depending on the thrust exerted by the second resilient means.
Claim 3
Dependent Claim
100 words
A pressure reducing valve according to claim 1, wherein the valve body is formed with a stepped bore closed at the end thereof having the largest diameter, the first plunger includes a first end portion slidable in and projecting from the other end of the said bore, an intermediate portion of larger diameter than the first end portion and carrying a seating ring co-operating with a seat in the bore, and a second end portion of smaller diameter than said first end portion extending through the annular plunger which is slidable in the largest diameter portion of the valve bore.
Claim 4
Dependent Claim
102 words
In a vehicle having a vehicle frame, road wheels, resilient suspension means supporting said road wheels, brakes on said wheels, a liquid pressure braking system for operating said brakes including a source of liquid pressure and motor cylinders to operate said brakes, the provision of a pressure reducing valve as claimed in claim 1 between said pressure source and motor cylinders of the braking system, the said reducing valve being mounted on the vehicle frame and the first resilient means being connected to said road wheels so as to be stressed to an extent which increases with the loading of the vehicle.
Claim 5
Dependent Claim
56 words
The combination of claim 3, wherein the said first resilient means comprise a blade spring pivotally mounted at one end on the vehicle frame, the said blade spring engaging thE first plunger of the reducing valve adjacent that end and being attached at its other end to an axle carrying the said wheels of the vehicle.
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) | 1976-11-19 | 1977-05-21 | 1977-11-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-19 | 1981-05-21 | 1981-11-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-19 | 1985-05-21 | 1985-11-20 | $7700.00 | Window Closed / Lapsed |