PNEUMATIC PARKING BRAKE RELEASING DEVICE FOR MOVING AND TOWING VEHICLES BY RELEASING A PARKING BRAKE BY DRIVING FORWARD OR REVERSELY AN ELECTRIC MOTOR WITH AN ELECTRONIC CONTROL UNIT

摘要

PURPOSE: A pneumatic parking brake releasing device is provided to move and tow vehicles by releasing a braking state of a parking brake with an electric motor although engine and brake air supply systems are broken down and accordingly the air is not supplied to a parking brake chamber. CONSTITUTION: A pneumatic parking brake releasing device is composed of a parking brake chamber(30) contacted with a main brake chamber(50) with interposing a flexible diaphragm(60) between the parking brake chamber and the main brake chamber; a sliding plate(32) sliding horizontally in the parking brake chamber; a guide bar(33) for guiding the sliding plate to slide only in the horizontal direction without rotating; a spring(34) for moving the sliding plate toward the main brake chamber as the pneumatic pressure in the chamber is decreased; a bolt(35) combined to a nut(31) formed at the sliding plate to execute a braking operation by pressing a push rod(52) of the main brake chamber by the diaphragm as the sliding plate moves; a motor(70) for regulating the length of the bolt projected from the sliding plate to the diaphragm by rotating the bolt; and an electronic control unit(80) for controlling and driving the motor.