Operating crane with gripper with main and auxiliary drives - actuates auxiliary drive, after gripper closure, until one gripper cable comes under preset tension

摘要

The crane operating system has a suspension cable (4) and a closure cable (4`) for the gripper, raised and lowered by the same main drive (1), with a auxiliary drive (1`) allowing relative adjustment of the 2 cables for opening and closing the gripper jaws. The auxiliary drive is maintained in operation after closure of the gripper jaws, until a defined tension is obtained in one cable. Pref. the latter cable tension is independent of the load. The crane operation is typically controlled by a computer (10), programmed by a memory. The auxiliary drive has a speed control coupled to the computer. ADVANTAGE - Simple, low-cost design for load distribution onto both cables.