Pneumatic hoist with precise load positioning - has linear motion transferred to shaft with fail=safe brake and pneumatic sensing valves

摘要

The purpose of the invention is to control a pneumatic cylinder type hoist such that widely varying loads can be lifted and precisely positioned, and the load can be sustained in the event of power failure. The cylinder (1) hangs from a shafer (2) which is mounted on a tranversing carriage (d). At the gripper end of the piston rod (3) is fastened an outer cylinder (8) which moves with the piston rod and has a peg (10) linked to an endless chain (11) running on two sprockets (12, 13). Movement of the hoist therefore causes shaft (2) and a braking disk (17) to rotate. A brake reaction disk (18) is spring loaded against the braking disk (17) but is released by actuation of a pneumatic cylinder (20). A radial arm on the brake reaction disk permits limited movement between two stops and also switches two sensing valves forming part of the control circuit. The circuit design causes the air pressure to be balanced against the load before the brake is released, thus enabling varying loads to be lifted at the same speed. USE/ADVANTAGE - Pallet loading systems; load manipulation in foundries refuse sorting systems. Low cost design with fail safe features.