Pneumatically actuated parking brake
First Claim
1. A parking brake system for a vehicle comprising:
- a hand control including a manually operated hand lever;
a parking brake actuator pneumatically actuated in response to a positive pressure generated by movement of said manually operated hand lever; and
a latching mechanism that selectively locks a vehicle brake in a park condition when said parking brake actuator is actuated wherein said latching mechanism initially locks the vehicle brake at a first mechanical parking force level and wherein said latching mechanism is automatically reactivated in response to the vehicle brake cooling subsequent to movement of said manually controlled hand lever into a park position and wherein reactivation of said latching mechanism generates a second mechanicaL parking force level that is greater than said first mechanical parking force level.
3 Assignments
0 Petitions
Accused Products
Abstract
A parking brake system uses a pneumatically controlled brake actuator to provide both service and parking brake functions. The parking brake system for a vehicle includes a hand control that is manually movable between a plurality of operational positions. A valve is responsive to movement of the hand control and controls air flow from a parking brake air supply to the pneumatically controlled brake actuator. The valve includes a gate that defines the plurality of operational positions, which include a park position, a release position, and an off position. When the hand control is moved out of the off position and into the park position, the pneumatically controlled brake actuator remains pressurized and a latching mechanism is activated to mechanically lock the vehicle brake. When the hand control is moved to the release position, the vehicle brakes are re-applied to unload the latching mechanism. The parking brake system can be used on vehicles equipped with an electronic braking system, or can be used on vehicles that do not have an electronic braking system.
10 Citations
20 Claims
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1. A parking brake system for a vehicle comprising:
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a hand control including a manually operated hand lever; a parking brake actuator pneumatically actuated in response to a positive pressure generated by movement of said manually operated hand lever; and a latching mechanism that selectively locks a vehicle brake in a park condition when said parking brake actuator is actuated wherein said latching mechanism initially locks the vehicle brake at a first mechanical parking force level and wherein said latching mechanism is automatically reactivated in response to the vehicle brake cooling subsequent to movement of said manually controlled hand lever into a park position and wherein reactivation of said latching mechanism generates a second mechanicaL parking force level that is greater than said first mechanical parking force level. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A method of actuating a parking brake system comprising the steps of
(a) manually moving a hand control lever out of an off position; -
(b) generating a positive air pressure to pneumatically apply a parking brake actuator in response to step (a); and (c) mechanically locking a vehicle brake in a park condition when the hand control lever is moved into a park position and the parking brake actuator is applied, including initially locking the vehicle brake at a first mechanical parking force level with a latch mechanism and automatically re-activating the latch mechanism in response to the vehicle brake cooling after the hand control lever is moved into the park position to generate a second mechanical parking force level that is greater than the first mechanical parking force level. - View Dependent Claims (17, 18, 19)
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20. A method of actuating a parking brake system comprising the steps of;
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(a) manually moving a hand control lever out of an off position; (b) generating a positive air pressure to pneumatically apply a parking brake actuator in response to step (a); and (c) mechanically locking a vehicle brake in a park condition when the hand control lever is moved into a park position and the parking brake actuator is applied, including initially locking the vehicle brake at a first mechanical parking force level with a latch mechanism, and automatically reactivating the latch mechanism in response to the vehicle brake cooling subsequent to movement of the hand control lever into the park position wherein reactivation of the latch mechanism generates a second mechanical parking force level that is greater than The first mechanical parking force level.
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Specification