Abstract:
A solenoid operated control valve for establishing an operational pressure differential in a servomotor located in a trailer to activate the wheel brakes of the trailer in response to an operational electrical signal derived from corresponding hydraulic actuation of the wheel brakes of a tow vehicle.
Abstract:
A control valve for use in a tow vehicle-trailer system to synchronize the activation of the trailer brakes with the brakes of the tow vehicle. The control valve transfers an operational signal to a servometer which pressurizes a first fluid to activate the trailer brakes in response to a second pressurized fluid which activates the brakes of the tow vehicle. A piston within the control valve has a first face joined to a smaller diameter second face by a stem with an axial opening. The second pressurized fluid acts on the first and second faces to move the axial opening against a seat when the pressure of the second pressurized fluid reaches an initial predetermined value. An increase in the pressure of the second pressurized fluid will act on the second face and move the piston away from the seat to allow the increase to modify the operational signal to the servometer.
Abstract:
A power brake system for a parking brake having a hydraulically operated spring brake with a manual control. A single stroke pump responsive to a pressure differential created by the flow of a first and second fluid under pressure regulated by the manual control is capable of pressurizing hydraulic fluid. This pressurized hydraulic fluid is adapted to overcome the resiliency of the spring brakes to maintain the parking brake in a released position. A flow control device adjacent the manual control will assure that a constant differential pressure is maintained in the pump to stabilize the force of the pressurized hydraulic fluid. An indicator responsive to the pressure of the hydraulic fluid provides a visual indication of the operational mode of the spring brake to an operator.
Abstract:
A control for positively regulating the alternate flow of partial vacuum from a source of air at atmospheric pressure to operate a pressure differential pump.