AN IMPROVED HEAD FRAME

摘要

A hoist frame (150) for engaging a pair of spreaders in an expanded position and a single spreader in a retracted positon comprising, a first and second head frame (65a, b), each for engaging a lifting device; a rigid first frame (160a) fixed to the first head frame and a rigid second frame (160b) fixed to the second head frame; a plurality of assemblies (155a,b) pivotably mounted to each fixed frame so as to be intermediate the head frames, wherein, each assembly comprises an upper horizontal member (175), a first inclined outer member (165) povotally mounted to the first fixed grame and pivotally mounted to a first end of the upper horizontal member, a second inclined outer member (185) pivotally mounted to the second fixed frame and pivotally mounted to a second end of the upper horizontal member, a first inclined inner member (170a) pivotaly mounted to the first fixed frame and picotally mounted to a mid-point of the upper horizontal member so as to be parallel to the first outer inclined member in a first positon of the hoist frame and a second inclined inner member (180) pivotally mounted to the second fixed frame and pivotally mounted to a mid-point of the upper horizontal member so as to be parallel to the second outer inclined member in a frist positon of the hoist frame, such that the first members and the first fixed frame define a first parallelogram (217), and the second member and the second fixed frame define a second parallelogram (216).