Inertial hand brake release apparatus

摘要

Apparatus (1) for automatically releasing a railroad car hand brake (HB) normally maintained in its applied position. An air pressure activated piston (11) acts on a hand brake release (5) to release the hand brake. An air conduit (13) directs pressurized air from a pressurized air source to the air cylinder. A normally closed first valve (25) is connected in the air conduit between the source and the air cylinder. A normally closed second valve (29) is connected in the air conduit between the source and a control inlet of the first valve. A sensor (33) senses an inertial load on the car and opens the second valve when the inertial load sensed exceeds a predetermined acceleration factor. Air pressure directed to the control inlet of the first valve through the second valve, when it is open, opens the first valve if the air pressure level is sufficiently great to release the air brakes of the car. The hand brake is released only if source pressure is sufficiently high and the inertial load sensed exceeds the acceleration factor.