A brake release mechanism for a spring-loaded, normally applied vehicle brake releasable by system hydraulic pressure when the system is disabled includes a pilot-operated brake release valve for isolating the brake from the disabled system, a brake control valve disposed between the system and the brake, and a manual hydraulic pump communicating with the brake for supplying fluid pressure thereto. A pilot-operated shunt valve is provided for shunting a hydraulic motor associated with the brake to allow free turning thereof during towing.
A tool for repairing an improperly positioned surface mounted component on the printed circuit board consisting of a body portion with a pair of legs positioned relative to the component mounting area on the printed circuit board with an included vacuum mechanism used to seize the component and reposition it against locating cams included in a pair of vertical legs.
A brake release apparatus for a vehicle equipped with a spring-applied hydraulically-released brake system. The apparatus includes a tow hook attached to the vehicle and operably connected to a hydraulic cylinder so that a towing force on the tow hook actuates the hydraulic cylinder. The hydraulic cylinder is connected to transmit a hydraulic pressure to the vehicle brakes, releasing the brakes to permit towing. A spring returns the tow hook to its original position when the towing force is removed, thereby permitting the spring-activated brakes to be reapplied.
A control arrangement for protecting the control circuit for a self propelled, automatically controlled wheeled vehicle having spring applied, electrically released brakes, to enable the vehicle to be manually pushed without damage to the vehicle control circuitry by generation of currents by the DC motors, the arrangement including a manually operable switch disconnecting the DC drive motors from the vehicle control circuit while simultaneously energizing a brake release actuator.
A braking apparatus for a hydraulic motor has a housing and a cylinder block. The apparatus includes fixed side frictional plates mounted to the housing and movable side frictional plates mounted to the cylinder block. In addition, a piston for pressing the fixed side frictional plates against the movable side frictional plates is also provided. A spring for thrusting the piston to move in a first direction thus tending to establish a first state in which the two sets of frictional plates are pressed together is also included. Furthermore, the apparatus includes a piston driving pressure receiving chamber disposed between the housing and the piston for thrusting the piston to move in a second direction under a pressure that is introduced into the piston driving pressure receiving chamber to establish a second state in which the two sets of frictional plates are separated from each other. The apparatus also includes a stopper for regulating a space between the fixed side frictional plates and the movable side frictional plates while the piston is moving in the second direction. In addition, the piston is movable in the second direction a distance that is greater than the size of the space.
A simplified brake control system comprises a source of pressurized fluid, a spring-set brake with a hydraulic release mechanism and a control valve connected between the brake and the source. The control valve has a valve body and a flow control mechanism in the body and mounted for movement between a first (solenoid-energized) position and a second (solenoid-de-energized) position. A one-way check valve is built into the valve body. How the system operates depends upon two factors, namely, (a) whether the valve flow control mechanism is in its first or its second position, and (b) the relationship of the pressure of the source, i.e., the first pressure, and the second pressure in the release mechanism. When the flow control mechanism is in the first position, the release mechanism may be pressurized for brake release. And when such mechanism is in the second position, the release mechanism is vented to the reservoir through the brake port, the second passage and the drain port. A new method for controlling a brake is also disclosed.