Tractor-trailer fluid pressure brake monitoring system
First Claim
1. In a vehicle having fluid-operated spring brakes and supply means for supplying operating fluid to the brakes whereby to release the brakes from a locked condition, security means to prevent unauthorized release of the brakes comprising a bistable solenoid valve for controlling the supply of fluid to the brakes, energizing circuit means for operating the valve, and limited access switching means interconnected with said energizing circuit means and and operable to set the solenoid valve selectively in an open or a closed condition.
1 Assignment
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Accused Products
Abstract
In a vehicle such as a tractor or a trailer having fluid-operated spring brakes to which fluid is supplied under pressure for releasing the brakes from a locked condition, security means are provided to prevent unauthorized release of the brakes. The security means comprises a bistable solenoid valve for controlling the supply of fluid to the brakes, energizing circuit means for operating the valve, and limited access switching means operable to set the solenoid valve selectively in an open or a closed condition.
40 Citations
7 Claims
- 1. In a vehicle having fluid-operated spring brakes and supply means for supplying operating fluid to the brakes whereby to release the brakes from a locked condition, security means to prevent unauthorized release of the brakes comprising a bistable solenoid valve for controlling the supply of fluid to the brakes, energizing circuit means for operating the valve, and limited access switching means interconnected with said energizing circuit means and and operable to set the solenoid valve selectively in an open or a closed condition.
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4. In a vehicle having fluid-operated spring brakes and supply means for supplying operating fluid to the brakes whereby to release the brakes from a locked condition, security means to prevent unauthorized release of the brakes comprising:
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a bistable solenoid valve for controlling the supply of fluid to the brakes, a first energizing circuit in series with a first solenoid operable to open the valve, a second energizing circuit in series with a second solenoid operable to close the valve, said first energizing circuit including a limited access switch and said second energizing circuit including normally open manually operable resetting switch. - View Dependent Claims (5, 6, 7)
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Specification