TRAVELLING BLOCK LIMIT SWITCH Russian patent published in 2002 - IPC

FIELD: drilling equipment. SUBSTANCE: invention relates to safety devices used in load lifting facilities employing block-and-tackle system. Proposed traveling block limit switch has limit switch valve and crossmember with weights. It has also worm on winch lifting shaft which is in meshing with worm wheel on which hook is mounted for catching rod loop and pulling out cotter from limit switch valve crossmember. Working travel of lifting hook and traveling block is adjusted by shifting catch hook in slot of worn wheel. EFFECT: reduced time taken for mounting operations, improved safety at operation with load lifting devices. 2 dwg