US3773362A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Proportioning valve with pressure limiting
Assignee: Bendix Corp
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Filing: 1971-12-01
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Granted: 1973-11-20
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Expires: 1991-12-01
Abstract
Abstract A proportioning valve is installed in the rear brake line of the vehicle equipped with separate brake hydraulic systems for the front and rear brakes. The proportioning valve permits uninhibited fluid communication to the rear wheel brakes until a first pressure level is attained whereupon the valve restricts flow of fluid to the rear wheel brakes to establish a lower fluid pressure level in the latter than the fluid pressure level communicated to the front wheel brakes. An additional valve in the rear brake line is responsive to the pressure differential across the proportioning valve to terminate fluid communication to the rear wheel brakes when the pressure differential across the proportioning valve attains a predetermined amount. This feature enables the relationship between the braking pressure delivered to the rear wheel brakes and the braking pressure delivered to the front wheel brakes to approximate closely the ideal pressure relationship. In one embodiment of the invention, the point at which fluid communication to the rear wheel brakes is initially restricted by the proportioning valve varies as the rate of deceleration of the vehicle varies. In a second embodiment of the invention, the pressure level at which the proportioning valve initially restricts fluid pressure communication to the rear wheel brakes varies as the load carried by the rear axle of the vehicle varies.
Inventors
- 👤 R Lewis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 06:56
CPC Classifications
B; B60; B60T; B60T8/00; B60T8/26; B60T8/28; B60T8/285; B60T11/00; B60T11/10; B60T11/28; B60T11/34; B60T8/18; B60T8/1812; B60T8/1831
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
148 words
In a vehicle having front and rear wheel brakes: first and second hydraulic systems communicated to said front and rear wheel brakes respectively; fluid motor means for simultaneously generating braking pressure in said first and second hydraulic systems; valve means in one of said hydraulic systems permitting unrestricted fluid communication through said one system until a first pressure level is attained in said system whereupon said valve means restricts communication through said one system to establish a lower pressure level at the corresponding wheel brakes than the fluid pressure level generated by said fluid motor means, said valve means including pressure differential responsive means terminating fluid communication to said corresponding wheel brakes when the pressure differential across said valve means attains a predetermined level; and sensing means responsive to the rate of deceleration of the vehicle to vary said first pressure level as the rate of deceleration wanes.
Claim 2
Dependent Claim
148 words
In a vehicle having front and rear wheel brakes: first and second hydraulic systems communicated to said front and rear wheel brakes respectively; fluid motor means for simultaneously generating braking pressure in said first and second hydraulic systems; valve means in one of said hydraulic systems permitting unrestricted fluid communication through said one system until a first pressure level is attained in said system whereupon said valve means restricts communication through said one system to establish a lower pressure level at the corresponding wheel brakes than the fluid pressure level generated by said fluid motor means, said valve means including pressure differential responsive means terminating fluid communication to said corresponding wheel brakes when the pressure differential across said valve means attains a predetermined level; and sensing means responsive to the rate of deceleration of the vehicle to vary said first pressure level as the rate of deceleration wanes.
Claim 3
Dependent Claim
158 words
In a vehicle having front and rear wheel brakes: first and second hydraulic systems communicated to said front and rear wheel brakes respectively; fluid motor means for simultaneously generating braking pressure in said first and second hydraulic systems; valve means in one of said hydraulic systems permitting unrestricted fluid communication through said one system until a first pressure level is attained in said system whereupon said valve means restricts communication through said one system to establish a lower pressure level at the corresponding wheel brakes than the fluid pressure level generated by said fluid motor means, said valve means including pressure differential responsive means terminating fluid communication to said corresponding wheel brakes when the pressure differential across said valve means attains a predetermined level; and means responsive to the weight carried by the axle of the vehicle mounting said corresponding set of wheel brakes to increase said first pressure level as the load carried by the vehicle increases.
Claim 4
Dependent Claim
158 words
In a vehicle having front and rear wheel brakes: first and second hydraulic systems communicated to said front and rear wheel brakes respectively; fluid motor means for simultaneously generating braking pressure in said first and second hydraulic systems; valve means in one of said hydraulic systems permitting unrestricted fluid communication through said one system until a first pressure level is attained in said system whereupon said valve means restricts communication through said one system to establish a lower pressure level at the corresponding wheel brakes than the fluid pressure level generated by said fluid motor means, said valve means including pressure differential responsive means terminating fluid communication to said corresponding wheel brakes when the pressure differential across said valve means attains a predetermined level; and means responsive to the weight carried by the axle of the vehicle mounting said corresponding set of wheel brakes to increase said first pressure level as the load carried by the vehicle increases.
Claim 5
Dependent Claim
19 words
The invention of claim 2: said one hydraulic system being communicated to the rear wheel brakes of the vehicle.
Claim 6
Dependent Claim
61 words
The invention of claim 2: said valve means including housing means defining a first bore therein, valve members within said first bore dividing the latter into an inlet chamber communicated to said fluid motor means and an outlet chamber communicated to said corresponding wheel brakes, said pressure differential responsive means responding to the pressure differential between said inlet and outlet chambers.
Claim 7
Dependent Claim
65 words
The invention of claim 4: said pressure differential responsive means including a plunger, valve mechanism responsive to movement of said plunger to terminaTe fluid communication between said outlet chamber and said corresponding wheel brakes, and means communicating the pressure level in said inlet chamber to one side of said plunger and the pressure level in said outlet chamber to the other side of said plunger.
Claim 8
Dependent Claim
108 words
The invention of claim 4: said pressure differential responsive means including a second bore defined within said housing means, a plunger slidably mounted within said second bore and defining a pair of compartments between opposite ends of the plunger and corresponding ends of the second bore; one of said compartments being communicated to said inlet chamber, the other compartment being communicated to said outlet chamber and to said corresponding wheel brakes; and second valve means in said second bore for terminating fluid communication between said other compartment and said corresponding wheel brakes upon sliding of said plunger when the pressure differential between said compartments attains a predetermined level.
Claim 9
Dependent Claim
38 words
The invention of claim 6; and resilient means yieldably urging said plunger toward one end of said bore, whereby the pressure differential between said compartments must exceed the force exerted by said resilient means before said plunger slides.
Claim 10
Dependent Claim
71 words
The invention of claim 6: said second valve means including a first valve member carried by said plunger and a second valve member mounted in said second compartment, said plunger sliding in said bore when a pressure differential of a predetermined magnitude is established across said plunger to urge said first valve member into sealing engagement with said second valve member to thereby prevent fluid communication to said corresponding wheel brakes.
References Cited (Backward Citations)
US3680922A
Cited
US3671080A
Cited
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 |