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 cylinder (9) acts on a hand brake release (5) to release the hand brake. An air line (13) directs pressurized air from a pressurized air source to the air cylinder. A valve (27) connected in the air line is responsive to the source air pressure. The valve is normally closed but opens when source air pressure reaches a level sufficient to release the air brakes on the car. A draft load sensor (29) is positioned in the air line between the valve and air cylinder. The sensor normally blocks the air line, but unblocks it when a sufficiently great draft load is sensed. The hand brake is released only if source air pressure is sufficiently high and the draft load on the railroad car is sufficiently great.