US3736842A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Breathing and failure detection system for spring brakes
Assignee: Bendix Corp
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Filing: 1972-02-22
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Granted: 1973-06-05
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Expires: 1992-02-22
Abstract
Abstract A service and spring brake actuator including service and spring brake chambers arranged in tandem, the spring brake chamber including a spring cavity and a control cavity and wherein valve means are provided for interconnecting the spring cavity with the service chamber and the control chamber during operation of the spring brake actuator in order to prevent the entry of dirt and other foreign matter into the spring cavity. Means are also provided for automatically indicating a failure or loss of load of the main spring and failure or serious leakage of the seal between the control and spring cavities.
Inventors
- 👤 H Valentine
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 19:59
CPC Classifications
F; F01; F01B; F01B19/00; F01B19/02; B; B60; B60T; B60T13/00; B60T13/10; B60T13/24; B60T13/26; B60T13/261; B60T17/00; B60T17/08; B60T17/083; B60T17/18; B60T17/22
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
176 words
In a tandem spring and service brake actuator for applying a vehicle brake, comprising a service actuator provided with a fluid pressure receiving chamber having a brake applying element therein, a spring actuator having a piston dividing the latter into a fluid pressure control cavity and a spring cavity, a piston rod connected with said piston and arranged to actuate the brake applying element of said service actuator and a spring within the spring cavity for operating said piston in one direction to apply the brake when fluid pressure is released from said control cavity, application of fluid pressure to said control cavity moving said piston in the opposite direction and compressing said spring to release the brake, the invention which comprises valve means for connecting said chamber and spring cavity during spring operation of said piston to apply the brake when fluid pressure is released from said control cavity and for connecting said control cavity and spring cavity when fluid pressure is applied to said control cavity to compress said spring and release the brake.
Claim 2
Dependent Claim
176 words
In a tandem spring and service brake actuator for applying a vehicle brake, comprising a service actuator provided with a fluid pressure receiving chamber having a brake applying element therein, a spring actuator having a piston dividing the latter into a fluid pressure control cavity and a spring cavity, a piston rod connected with said piston and arranged to actuate the brake applying element of said service actuator and a spring within the spring cavity for operating said piston in one direction to apply the brake when fluid pressure is released from said control cavity, application of fluid pressure to said control cavity moving said piston in the opposite direction and compressing said spring to release the brake, the invention which comprises valve means for connecting said chamber and spring cavity during spring operation of said piston to apply the brake when fluid pressure is released from said control cavity and for connecting said control cavity and spring cavity when fluid pressure is applied to said control cavity to compress said spring and release the brake.
Claim 3
Dependent Claim
49 words
The actuator of claim 1 wherein said valve means includes a spring-closed check valve carried by said piston rod, and a stationary part for opening said check valve to connect the spring cavity and control cavity when said piston is moved in said opposite direction to a predetermined position.
Claim 4
Dependent Claim
60 words
The actuator of claim 2 which includes an interior wall within the actuator separating the chamber and control cavity, said piston rod including a hollow sleeve passing through an opening in said wall and having an end portion for actuating said brake applying element and wherein said valve means includes a seal carried by said wall and engaging said sleeve.
Claim 5
Dependent Claim
58 words
The actuator of claim 3 which includes a valve cavity in communication with said spring cavity when said check valve is open, said sleeve being provided with an opening arranged to be uncovered by said seal to connect said valve cavity and said control cavity when said piston is moved in said opposite direction to compress the spring.
Claim 6
Dependent Claim
26 words
The actuator of claim 4 wherein said opening is arranged to connect the valve cavity and chamber when the piston is moved in said one direction.
Claim 7
Dependent Claim
45 words
The actuator of claim 1 which includes means for supplying fluid pressure to said chamber, and means dependent upon operation of the last named means for supplying fluid pressure to said control cavity after the brake has been applied by spring operation of said piston.
Claim 8
Dependent Claim
45 words
The actuator of claim 1 which comprises in addition a detection system for indicating failure of said spring actuator comprising a pressure differential switch subjected to opposing pressures in said control and spring cavities, a signal, and electrical circuit means interconnecting said switch and signal.
Claim 9
Dependent Claim
26 words
The actuator of claim 7 wherein said switch is constructed and arranged to close when the pressures in said control and spring cavities are substantially equal.
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) | 1976-06-04 | 1976-12-04 | 1977-06-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-04 | 1980-12-04 | 1981-06-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-04 | 1984-12-04 | 1985-06-05 | $7700.00 | Window Closed / Lapsed |