초록 ▼

A motor drives a pump to provide fluid under pressure in a closed hydraulic circuit through a pilot valve to a change speed clutch valve and a directional valve of a multi-speed transmission for an electrically powered vehicle, such as a mine haulage vehicle. The multi-speed transmission is connecte

A motor drives a pump to provide fluid under pressure in a closed hydraulic circuit through a pilot valve to a change speed clutch valve and a directional valve of a multi-speed transmission for an electrically powered vehicle, such as a mine haulage vehicle. The multi-speed transmission is connected by an output shaft to the driven wheels of the vehicle. A braking force is applied to the driven wheels by a hydraulically operated service brake to effect routine stopping of the vehicle. Under emergency conditions an emergency brake applies a braking force to the driven wheels by operation of a panic bar positioned in the operator\s compartment. A brake valve connected to the panic bar maintains a preselected fluid pressure in the hydraulic circuit of the emergency brake to retain the brake in a released position. The hydraulic circuit is interlocked through the pilot valve to the transmission clutch and direction valves. Depressing the panic bar actuates the brake valve to release the emergency brake and simultaneously actuate the pilot valve to interrupt fluid flow to the respective valves of the transmission. Transmission of power to the driven wheels is terminated, and the vehicle is stopped. Actuation of the panic bar also opens the main contactors of the electrical controller that supplies electrical power to the traction motors. Upon application of the emergency brake, the traction motors must be restarted before the vehicle can be moved, and a lever of the brake valve must be shifted from the park to run position. Thus, the emergency brake is confined to emergency use only and is not to be used as a service brake to provide less wear to preserve the emergency brake for emergency use.

대표청구항 ▼

A brake actuator for a vehicle comprising, propelling means for said vehicle, electric traction motors connected to said propelling means, an electric circuit to supply current to said electric traction motors, fluid pressure operated switch means to open and close said circuit, said fluid pressure

A brake actuator for a vehicle comprising, propelling means for said vehicle, electric traction motors connected to said propelling means, an electric circuit to supply current to said electric traction motors, fluid pressure operated switch means to open and close said circuit, said fluid pressure operated switch means arranged when subjected to fluid under pressure to close said circuit and energize said electric traction motors, fluid actuated brake means for engaging said propelling means and braking said vehicle, a source of fluid under pressure, a brake actuator valve, a fluid circuit for controlling the flow of fluid under pressure between said source of fluid under pressure to said brake actuator valve, said fluid actuated braking means and said fluid pressure operated switch means, said brake actuator valve arranged in a brake disengaged position to supply said fluid actuated brake means with fluid under pressure from said source and maintain said fluid actuated brake means in a brake disengaged position, said brake actuator valve arranged in a brake engaged position to vent said fluid under pressure from said fluid actuated brake means and vent said fluid under pressure from said fluid pressure operated switch means so that upon engagement of said fluid actuated brake means said fluid pressure operated switch means opens said circuit and deenergizes said traction motors, and brake reset means connected to said brake actuator valve for maintaining said brake in an engaged position after actuation of said brake actuator valve.