Claims
- 1. A vehicular brake system comprising:
(A) at least one hydraulically actuated vehicle brake; (B) a master cylinder which has an inlet in fluid communication with a hydraulic fluid reservoir and an outlet in fluid communication with said brake, wherein said master cylinder is configured to be latched in an actuated position thereof to hold said brake in an engaged condition; (C) an accumulator which is dimensioned and configured to store energy generated by said master cylinder during an energy storage phase of a braking cycle master cylinder and to use said energy to assist in holding said brake in said engaged condition when said master cylinder is locked in said actuated position thereof; and (D) a booster which is coupled to said accumulator and which is automatically operated during a braking cycle to boost a magnitude of energy stored by said accumulator during an energy storage phase of a subsequent braking cycle without requiring manual deactivation of said booster.
- 2. A vehicular brake system as recited in claim 1, wherein said accumulator comprises a spring which is compressed upon master cylinder actuation to store energy, and wherein said booster interacts with said accumulator such that said spring is compressed more during the energy storage phase of the subsequent braking cycle than during the energy storage phase of the first braking cycle.
- 3. A vehicular brake system as recited in claim 2, wherein said spring is preloaded so as to set a threshold pressure below which at least substantially all work performed by said master cylinder is applied toward hydraulic pressure intensification and above which at least a portion of the work performed by said master cylinder is applied towards accumulator spring compression and energy storage, said threshold pressure being at least slightly higher after the subsequent brake and hold cycle than before the first brake and hold cycle.
- 4. A vehicular brake system as recited in claim 1, further comprising a brake pedal that is manually actuatable to at least indirectly actuate said master cylinder and said booster, said brake pedal being movable during a brake and hold cycle from a released position, through a service braking stroke in which said master cylinder is actuated to apply said brake, to a latched position in which said master cylinder is latched in said actuated position to hold said brake in said applied condition, and back to said released position, wherein said booster automatically engages said accumulator following unlatching of a latched brake pedal and is held out of active engagement with said accumulator during the energy storage phase.
- 5. The vehicular brake system as recited in claim 4, further comprising
a support on which said master cylinder and said accumulator are supported, wherein
said booster comprise an indexing arm and a spacer that is mounted on said indexing arm and that has a variable effective thickness, and wherein said indexing arm cooperates with said brake pedal such that, upon movement of said brake pedal toward said released position from said latched position, said indexing arm swings into an engaged position in which at least a portion of said spacer is lodged between an axial surface of said accumulator and a surface of said support.
- 6. The vehicular brake system as recited in claim 5, wherein said booster further comprises an actuator arm which is driven by said brake pedal to move either toward or away from said accumulator, and further comprising a return spring which urges said indexing arm either away from or toward said accumulator.
- 7. The vehicular brake system as recited in claim 6, wherein said actuator arm extends at least generally transversely from said indexing arm to a position in which said actuator arm is engaged by said brake pedal as said brake pedal moves from said released position towards said latched position.
- 8. The vehicular brake system as recited in claim 6, wherein said brake pedal is movable beyond said latched position to an overtravel position, and wherein said spacer is spaced further from said accumulator when said pedal is in said overtravel position than when said brake pedal is in said latched position.
- 9. The vehicular brake system as recited in claim 5, wherein said spacer comprises a stack of spacer plates that are mounted on said indexing arm, and wherein the effective thickness of said spacer is determined by the number of spacer plates that act upon said accumulator.
- 10. The vehicular brake system as recited in claim 9, wherein
each of said spacer plates has an inner surface which faces said accumulator and an outer surface which is disposed opposite said inner surface, and wherein said booster further comprises a biasing arrangement which biases said spacer plates toward said accumulator but which permits limited independent movement of each of said spacer plates relative to said indexing arm away from said accumulator upon contact between said spacer plates and a peripheral surface of said accumulator.
- 11. The vehicular brake system as recited in claim 10, wherein said biasing arrangement comprises a leaf spring assembly mounted on said indexing arm.
- 12. The vehicular brake system as recited in claim 10, wherein
said accumulator further comprises a stationary cap on which a first end of said spring is seated and a compression plate on which a second end of said spring is seated and which is movable relative to said cap upon actuation of said master cylinder to compress said spring, wherein said spacer plates engage said compression plate when said brake pedal is in said released position and automatically move away from said compression plate during movement of said bake pedal into said latched position, and wherein, said accumulator, said spacer plates, and said indexing arm are dimensioned and configured such that, prior to initiation of the first braking cycle, all of said spacer plates engage a peripheral surface of said compression plate, and after the end of the first braking cycle, at least one of said spacer plates is lodged between an axial end of said compression plate and said mount to set the effective thickness of said spacer.
- 13. A vehicular brake system comprising:
(A) at least one hydraulically actuated vehicle brake; (B) a brake pedal which is movable through a braking cycle in which said brake pedal moves from a released position, through a service braking stroke, to a latched position, is latched in the latched position, and then moves back to the released position; (C) a master cylinder housing which has a front wall; (D) a master cylinder which is mounted on said housing, which has an inlet in fluid communication with a hydraulic fluid reservoir and an outlet in fluid communication with said brake, which is actuated by said brake pedal to engage said brake when said bake pedal travels through said service braking stroke, and which is latched in said actuated position when said brake pedal is latched in said latched position thereof; (E) a hydraulic accumulator which is coupled to said master cylinder, which extends toward said front wall of said mounting bracket, and which is dimensioned and configured to store energy generated by said master cylinder upon actuation thereof and to use said energy to assist in holding said brake in the engaged condition thereof when said master cylinder is locked in said actuated position thereof, said accumulator including 1) a compression spring having an outer, stationary end and an inner, movable end and 2) a compression plate on which said inner end of said spring rests; and (F) a booster which is automatically operated during at least a portion of a first braking cycle of said brake system to boost an energy storage level of said accumulator during another, subsequent braking cycle without requiring manual deactivation of said booster, said booster comprising
1) an indexing arm which is pivotably mounted on said front wall of said mounting bracket; 2) a stack of spacer plates which are mounted on said indexing arm, and each of which has an inner surface which faces said compression plate and an outer surface which is disposed opposite said inner surface, 3) a biasing arrangement which biases said spacer plates toward said compression plate and which permits limited movement of said spacer plates relative to said indexing arm upon contact between said spacer plates and a peripheral surface of said compression plate, 4) a return spring which biases said indexing arm toward a position in which said spacer plates engage said compression plate, and 5) an actuator arm which extends rearwardly from said indexing arm toward said brake pedal, wherein said actuator arm cooperates with said brake pedal such that,
a) during movement of said brake pedal into the latched position following a service braking stroke, said actuator arm is driven by said brake pedal to move said indexing arm into a disengaged position in which all of said spacer plates are spaced radially from said peripheral surface of said compression plate in order to permit unhindered axial movement of said compression plate past said spacer plates, and b) upon release of said brake pedal from said latched position, said return spring automatically moves said indexing arm to an engaged position in which at least one spacer plate of said stack is lodged between an axial surface of said compression plate and said front wall of said master cylinder housing.
- 14. A brake booster comprising:
A) an indexing arm which is configured for pivotal mounting on a surface of a brake system, said indexing arm having inner and outer surfaces and front and rear surfaces; B) an actuator arm which is coupled to said indexing arm, which extends beyond said rear surface of said indexing arm, and which is configured for engagement with a brake pedal; and C) a variable thickness spacer which is mounted on said indexing arm and which is configured to selectively lodge between an axial surface of an accumulator and another surface of the brake system when said indexing arm is driven into an engaged position thereof in response to release of the brake pedal from a latched position thereof.
- 16. The booster as recited in claim 15, further comprising a return spring which is coupled to said indexing arm which is configured to bias said indexing arm toward said engaged position.
- 17. The indexing arm as recited in claim 15, wherein said spacer includes a stack of spacer plates, each of which has an inner surface which is configured to face the accumulator and a outer surface which is disposed opposite said inner surface, and further comprising a biasing arrangement which configured to bias said spacer plates toward a said inner surface of said indexing arm while permitting limited movement of said spacer plates relative to said indexing arm.
- 18. A method comprising:
(A) actuating a brake pedal of a vehicular brake system from a released position and through a brake and latch and phase of a first braking cycle to sequentially apply at least one hydraulically actuated brake of said vehicle and latch said brake in the applied condition, wherein, during at least a latter portion of said brake and latch phase, an accumulator is energized at least indirectly by movement of said brake pedal to store energy in said accumulator; then (B) releasing said brake pedal during a return phase of said first braking cycle to return said brake to said released position, wherein, during the return phase, only a portion of the energy stored by said accumulator during the first actuating step is released; (C) actuating said brake pedal through a brake and latch phase of a second braking cycle to sequentially apply said brake and latch said brake in said applied condition and to store energy in said accumulator, wherein a magnitude of energy stored by said accumulator during said second braking cycle is greater than a magnitude of energy stored during said first braking cycle.
- 19. The method as recited in claim 18, further comprising completing N+M additional braking cycles, where N and M are both greater than 1, and wherein said accumulator stores at least essentially the same magnitude of the energy during each of the N+1st through Mth braking cycles.
- 20. The method as recited in claim 19, wherein said accumulator releases at least essentially the same magnitude of energy during the release phase of each of the N+1st through Mth braking cycles.
- 21. The method as recited in claim 19, wherein a compression spring of said accumulator is compressed to lengths L1 and L2 during the brake and latch phases of the first and second braking cycles, respectively, L2 being less than L1, and wherein said spring is compressed to a length LF during the brake and latch phase of each of the N+1st and subsequent braking cycles, LF being less than L2.
- 22. The method as recited in claim 21, wherein a movable axial surface of said accumulator is located at an initial position P1 prior to the first braking cycle, and further comprising returning said axial surface to a second position P2 during the release phase of the first braking cycle and then holding said axial surface in the position P2 until the brake and latch phase of the second braking cycle, P2 being spaced from P1 by a distance L1-L2.
- 23. The method as recited in claim 22, wherein the holding step comprises inserting a spacer of an effective thickness equal to P2 between said axial surface of said accumulator and as stationary surface of said brake system, thereby preventing further movement of said axial surface toward said stationary surface and preventing further energy release.
- 24. The method as recited in claim 23, wherein said spacer is of a variable effective thickness, and wherein following each of the N+1st and subsequent braking cycles, the spacer has an effective thickness Pf equal to L1-Lf.
- 25. The method as recited in claim 23, wherein said spacer comprises a stack of spacer plates mounted on an indexing arm, and wherein an effective thickness of said spacer after each braking cycle is determined by the number of plates lodged betweens said axial surface of said accumulator and said stationary surface of said braking system at that time.
- 26. The method as recited in claim 23, wherein said spacer is mounted on an indexing arm that automatically 1) moves said spacer away from said accumulator during an energy storage portion of the brake and latch phase of each braking cycle in which said accumulator spring is being compressed and 2) moves into a position in which said spacer lodges between said axial surface of said accumulator and said stationary surface during the release phase of each braking cycle.
- 27. The method as recited in claim 26, wherein said brake pedal drives said indexing arm away from said accumulator during said energy storage portion of each braking cycle and a return spring drives said indexing arm toward said accumulator during the release phase of each braking cycle.
- 28. A vehicle comprising:
(A) at least front and rear wheels; and (B) a combined service/parking brake system including
(1) a plurality of hydraulically actuated brakes, one of which brakes each of said wheels, and (2) a brake actuator assembly that can be operated to effect both service braking and park and hold braking, wherein said brake system is configured such that all of said brakes are engaged during park and hold braking.
- 29. The vehicle as recited in claim 28, wherein said vehicle is a four-wheeled vehicle having two front wheels an two rear wheels, and wherein said brake system is configured such that both front brakes and both rear brakes are engaged during park and hold braking.
- 30. A vehicle brake system comprising:
(A) at least first and second hydraulically-actuated vehicle brakes; (B) a manually actuated multi-outlet master cylinder which has an inlet in fluid communication with a hydraulic fluid reservoir and at least first and second outlets in fluid communication with said first and second brakes, respectively, wherein said master cylinder is configured to be locked in an actuated position thereof to hold said brakes in an engaged condition; and (C) a hydraulic accumulator which has an inlet in fluid communication with at least one of said outlets of said master cylinder and which is dimensioned and configured to store energy generated by said master cylinder upon actuation thereof and to use said energy to assist in holding at least one of said first and second brakes in said engaged condition when said master cylinder is locked in said actuated position thereof.
- 31. The vehicle brake system as recited in claim 30, wherein said inlet of said accumulator is in fluid communication with only one of said outlets of said master cylinder and is dimensioned and configured to assist in holding only one of said first and second brakes in said engaged condition when said master cylinder is locked in said actuated position thereof.
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S. patent application Ser. No. 09/914,867, which is a national phase of PCT Application Ser. No. PCT/US00/05427, filed Mar. 2, 2000, which claims the benefit of priority of U.S. Provisional Application Ser. No. 60/122,405, filed Mar. 2, 1999, the entire contents of each of which are hereby expressly incorporated by reference into the present application.
Provisional Applications (1)
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Number |
Date |
Country |
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60122405 |
Mar 1999 |
US |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
09914867 |
Mar 2002 |
US |
Child |
10308970 |
Dec 2002 |
US |