US3768608A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydraulic spring brake control system
Assignee: Bendix Corp
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Filing: 1971-01-20
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Granted: 1973-10-30
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Expires: 1991-01-20
Abstract
Abstract A vehicle hydraulic braking system is disclosed which includes a hydraulic brake booster which operates a standard automotive master cylinder. Disc brakes which include a hydraulic service actuator and spring-applied parking actuator are mounted on at least two of the wheels of the vehicle. Pressurized fluid from a hydraulic source, such as the vehicle''s power steering pump, is used to operate the brake booster when a service brake application is effected. The spring actuator on each of the disc brakes includes a pressure responsive device that opposes the resiliency of the springs. Fluid is communicated from the booster pressure chamber to the pressure responsive device when the engine of the vehicle is started and the first brake application is effected to release the spring actuator. A control valve is provided so that fluid may be purged from the pressure responsive means when the vehicle is parked or when an emergency occurs. The fluid pressure from the booster pressure chamber is communicated to a pressure intensifier which increases the fluid pressure level that is provided to the pressure responsive means. The pressure intensifier includes a manually operated device to release the spring brake when a malfunction in the vehicle''s hydraulic system prevents fluid communication to the booster pressure chamber.
Inventors
- 👤 K Fulmer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 19:56
CPC Classifications
F; F16; F16D; F16D65/00; F16D65/38; F16D65/40; F16D65/52; F16D65/56; F16D65/567; B; B60; B60T; B60T13/00; B60T13/10; B60T13/12; B60T13/14; B60T13/142; B60T13/145; B60T13/146; B60T13/22; B60T17/00; B60T17/18; B60T17/22; B60T17/226; F16D65/14; F16D65/16; F16D65/18; F16D2121/00; F16D2121/02; F16D2121/12; F16D2123/00; F16D2127/00; F16D2127/02; F16D2127/04
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
357 words
In a vehicle hydraulic system: a fluid pressure source; a hydraulic brake actuating assembly including a master cylinder portion and a brake booster portion; said booster portion including a housing defining a pressure chamber therewithin, a piston slidably mounted in said pressure chamber and operably connected to said master cylinder portion, and operator-operated valve means for controlling fluid communication between the pressure chamber and the pressure source for sliding said piston to develop braking pressure in said master cylinder portion; a brake including a service actuator communicated to said master cylinder portion and a brake booster portion; said booster portion including a housing defining a pressure chamber therewithin, a piston slidably mounted in said pressure chamber and operably connected to said master cylinder portion, and operator-operated valve means for controlling fluid communication between the pressure chamber and the pressure source for sliding said piston to develop braking pressure in said master cylinder portion; a brake including a service actuator communicated to said master cylinder portion for effecting a brake application when braking pressure is developed in the master cylinder, and a spring actuator including resilient means yieldably urging said brake into an applied condition and pressure responsive means opposing said resilient means when pressurized fluid is communicated to said pressure responsive means; structure communicating said pressure responsive means to said pressure chamber to thereby prevent said resilient means from urging said brake into an applied condition when pressurized fluid is admitted into said pressure chamber; said structure including a pressure intensifying device to increase the fluid pressure level delivered to said pressure responsive means to a valve higher than the fluid pressure level in said pressure level and a first conduit communicating said intensifying device to the pressure chamber, check valve means in said conduit to maintain the pressure level in said intensifying device and therefore the pressure communicated to said other means at a level sufficient to oppose the resilience of said resilient means after pressurized fluid is admitted into said pressure chamber; and an operator-actuated control valve for venting said intensifying device to a fluid reservoir to permit said resilient means to apply said brake.
Claim 2
Dependent Claim
357 words
In a vehicle hydraulic system: a fluid pressure source; a hydraulic brake actuating assembly including a master cylinder portion and a brake booster portion; said booster portion including a housing defining a pressure chamber therewithin, a piston slidably mounted in said pressure chamber and operably connected to said master cylinder portion, and operator-operated valve means for controlling fluid communication between the pressure chamber and the pressure source for sliding said piston to develop braking pressure in said master cylinder portion; a brake including a service actuator communicated to said master cylinder portion and a brake booster portion; said booster portion including a housing defining a pressure chamber therewithin, a piston slidably mounted in said pressure chamber and operably connected to said master cylinder portion, and operator-operated valve means for controlling fluid communication between the pressure chamber and the pressure source for sliding said piston to develop braking pressure in said master cylinder portion; a brake including a service actuator communicated to said master cylinder portion for effecting a brake application when braking pressure is developed in the master cylinder, and a spring actuator including resilient means yieldably urging said brake into an applied condition and pressure responsive means opposing said resilient means when pressurized fluid is communicated to said pressure responsive means; structure communicating said pressure responsive means to said pressure chamber to thereby prevent said resilient means from urging said brake into an applied condition when pressurized fluid is admitted into said pressure chamber; said structure including a pressure intensifying device to increase the fluid pressure level delivered to said pressure responsive means to a valve higher than the fluid pressure level in said pressure level and a first conduit communicating said intensifying device to the pressure chamber, check valve means in said conduit to maintain the pressure level in said intensifying device and therefore the pressure communicated to said other means at a level sufficient to oppose the resilience of said resilient means after pressurized fluid is admitted into said pressure chamber; and an operator-actuated control valve for venting said intensifying device to a fluid reservoir to permit said resilient means to apply said brake.
Claim 3
Dependent Claim
270 words
In a vehicle hydraulic system: a fluid pressure source; a hydraulic brake actuating assembly including a master cylinder portion and a brake booster portion; said booster portion including a housing defining a pressure chamber therewithin, a piston slidably mounted in said pressure chamber and operably connected to said master cylinder portion, and operator-operated valve means for controlling fluid communication between the pressure chamber and the pressure source for sliding said piston to develop braking pressure in said master cylinder portion; a brake including a service actuator communicated to said master cylinder portion for effecting a brake application when braking pressure is developed in the master cylinder, and a spring actuator including resilient means yieldably urging said brake into an applied condition and pressure responsive means opposing said resilient means when pressurized fluid is communicated to said pressure responsive means; structure communicating said pressure responsive means to said pressure chamber to thereby prevent said resilient means from urging said brake into an applied condition when pressurized fluid is admitted into said pressure chamber; said structure including a pressure intensifying device having a housing defining a stepped bore therewithin having larger and smaller diameter sections with a shoulder therebetween, a stepped piston having a larger diameter portion slidable in the larger portion of the bore, and a smaller diameter portion slidable in the smaller portion of the bore, the larger and smaller ends of the piston cooperating with the corresponding ends of the bore to define first and second fluid chambers respectively therebetween; said first chamber being communicated to said pressure chamber; said second chamber being communicated to said pressure responsive means.
Claim 4
Dependent Claim
270 words
In a vehicle hydraulic system: a fluid pressure source; a hydraulic brake actuating assembly including a master cylinder portion and a brake booster portion; said booster portion including a housing defining a pressure chamber therewithin, a piston slidably mounted in said pressure chamber and operably connected to said master cylinder portion, and operator-operated valve means for controlling fluid communication between the pressure chamber and the pressure source for sliding said piston to develop braking pressure in said master cylinder portion; a brake including a service actuator communicated to said master cylinder portion for effecting a brake application when braking pressure is developed in the master cylinder, and a spring actuator including resilient means yieldably urging said brake into an applied condition and pressure responsive means opposing said resilient means when pressurized fluid is communicated to said pressure responsive means; structure communicating said pressure responsive means to said pressure chamber to thereby prevent said resilient means from urging said brake into an applied condition when pressurized fluid is admitted into said pressure chamber; said structure including a pressure intensifying device having a housing defining a stepped bore therewithin having larger and smaller diameter sections with a shoulder therebetween, a stepped piston having a larger diameter portion slidable in the larger portion of the bore, and a smaller diameter portion slidable in the smaller portion of the bore, the larger and smaller ends of the piston cooperating with the corresponding ends of the bore to define first and second fluid chambers respectively therebetween; said first chamber being communicated to said pressure chamber; said second chamber being communicated to said pressure responsive means.
Claim 5
Dependent Claim
252 words
In a vehicle hydraulic system: a fluid pressure source; a hydraulic brake actuating assembly including a master cylinder portion and a brake booster portion; said booster portion including a housing defining a pressure chamber therewithin, a piston slidably mounted in said pressure chamber and operably connected to said master cylinder portion, and operator-operated valve means for controlling fluid communication between the pressure chamber and the pressure source for sliding said piston to develop braking pressure in said master cylinder portion; a brake including a service actuator communicated to said master cylinder portion for effecting a brake application when braking pressure is developed in the master cylinder, and a spring actuator including resilient means yieldably urging said brake into an applied condition and pressure responsive means opposing said resilient means when pressurized fluid is communicated to said pressure responsive means; structure communicating said pressure responsive means to said pressure chamber to thereby prevent said resilient means from urging said brake into an applied condition when pressurized fluid is admitted into said pressure chamber; said structure including a check valve dividing said structure into a first section between the check valve and the pressure chamber and a second section between the check valve and said pressure responsive means, said check valve being effective to prevent return flow of fluid through said structure into said pressure chamber; and conduit means communicating said second section to a fluid reservoir; said conduit means including operator-actuated control means for initiating and terminating fluid communication through said conduit means.
Claim 6
Dependent Claim
252 words
In a vehicle hydraulic system: a fluid pressure source; a hydraulic brake actuating assembly including a master cylinder portion and a brake booster portion; said booster portion including a housing defining a pressure chamber therewithin, a piston slidably mounted in said pressure chamber and operably connected to said master cylinder portion, and operator-operated valve means for controlling fluid communication between the pressure chamber and the pressure source for sliding said piston to develop braking pressure in said master cylinder portion; a brake including a service actuator communicated to said master cylinder portion for effecting a brake application when braking pressure is developed in the master cylinder, and a spring actuator including resilient means yieldably urging said brake into an applied condition and pressure responsive means opposing said resilient means when pressurized fluid is communicated to said pressure responsive means; structure communicating said pressure responsive means to said pressure chamber to thereby prevent said resilient means from urging said brake into an applied condition when pressurized fluid is admitted into said pressure chamber; said structure including a check valve dividing said structure into a first section between the check valve and the pressure chamber and a second section between the check valve and said pressure responsive means, said check valve being effective to prevent return flow of fluid through said structure into said pressure chamber; and conduit means communicating said second section to a fluid reservoir; said conduit means including operator-actuated control means for initiating and terminating fluid communication through said conduit means.
Claim 7
Dependent Claim
95 words
The invention of claim 2: spring means yieldably urging the larger end of the piston toward the corresponding end of said bore to thereby reduce the fluid pressure level in said second chamber when the first chamber is vented to said fluid reservoir; and manually manipulable means carried by the housing for urging said piston away from the larger end of the housing to communicate fluid to said pressure responsive means at a pressure level sufficient to oppose said resilient means when a malfunction prevents fluid communication into said first chamber from said pressure chamber.
Claim 8
Dependent Claim
43 words
The invention of claim 2: the fluid communicated into said first chamber being hydraulic fluid, the fluid in said second chamber communicated to said pressure responsive means being brake fluid; and a reservoir communicated to said other chamber for storing said brake flUid.
Claim 9
Dependent Claim
65 words
The invention of claim 1: a warning device mounted in the vehicle operator''s compartment; and pressure responsive switch means responsive to the fluid pressure level at said pressure responsive means to actuate said warning device when the fluid pressure level at said pressure responsive means falls below a predetermined value, to thereby inform the vehicle operator that said spring actuator has effected a brake application.
Claim 10
Dependent Claim
34 words
The invention of claim 3; and a pressure intensifying device in said second section for supplying fluid to said pressure responsive means at a higher pressure level than that available to said pressure chamber.
Claim 11
Dependent Claim
31 words
The invention of claim 3; and manually manipulable means on said second section releasing said spring actuator when a malfunction prevents fluid communication between the pressure chamber and said other areas.
Claim 12
Dependent Claim
61 words
The invention of claim 3: a warning device mounted in the vehicle operator''s compartment; and pressure responsive switch means sensitive to the fluid pressure level in said second section to actuate said warning device when the pressure level in said second section falls below a predetermined level to inform the vehicle operator that said spring actuator has effected a brake application.
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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) | 1976-10-29 | 1977-04-30 | 1977-10-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-29 | 1981-04-30 | 1981-10-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-29 | 1985-04-30 | 1985-10-30 | $7700.00 | Window Closed / Lapsed |