Patent ID: 7565982
Filing Date: 2009-07-28
Classification: B66C

Abstract:
1. A boom hoisting device of a crane, said boom hoisting device being mounted on a body frame of the crane having a boom capable of rising and lowering and causing the boom to rise and lower, said boom hoisting device comprising: a mast, said mast having a base end portion connected to said body frame removably and pivotably about an approximately horizontal axis and further having a front end portion connected to a front end portion of said boom through a guy line; a mast-side spreader provided at the front end portion of said mast; a frame-side spreader removably mountable to said body frame, wherein said frame-side spreader is dismounted from said body frame with a hoisting rope being stretched between and spread on both said frame-side spreader and said mast-side spreader; and a hoisting winch directly mounted to said mast and adapted to unwind and wind said hoisting rope to raise and lower said mast and said boom, wherein the mast and the hoisting winch may together be removed from said body frame by disconnecting the frame-side spreader from the body frame and by disconnecting the base end portion of the mast from the body frame during transport.