Gantry mounted double grab mechanism - has storage drums actuating grabs and providing additional rope when working at different depths

摘要

The grab mechanism has two grabs travelling on a gantry and coupled to a common hoisting and closing mechanism, so that one is lifted as the other is lowered. When the grabs are working at different depths, the additional rope lengths are provided by two storage drums (5, 6). - The drives to these drums effect the corresponding lifting and lowering motions. To control the end position of the grabs (1, 2) slack rope contacts (11, 12) and limit switches (13, 14) casn be provided. The design allows the grabs to work at widely differing depths.