PURPOSE: To perform the mast removal of a tower crane easily by locking a crane body an uppermost floor skeleton and supporting it tight with an outrigger at the position after the completion of skeletal construction work with the tower crane, and then lifting up the upper masts successively.
CONSTITUTION: When uppermost floor skeletal construction work is completed, two outriggers 10 and 10 are overhung, and each hydraulic cylinder 11 is situated on the specified steel frame, and then these hydraulic cylinders 11 and 11 are pushed out. In addition a crane body 4 is supported by the steel frame via these hydraulic cylinders 11 and the outriggers 10. Subsequently, a mast upper part being inserted through an opening part of a swivel base 12 of this crane body 4 and slightly projecting upward from this upper end is hitched on a hook at the end of a boom 13, lifting it just above, and thus it is removed. At this time, a climbing boom 6 is stored in a lower part of the outrigger 10 in advance after contracting another hydraulic cylinder 7. In succession, the next mast upper part is hitched on by the hook, lifting up as it is for removal. This operation is repeated successively, whereby this mast upper part is lifted up to the mast and a footing base for removal.
OKAFUJI MASANOBU
OGOSHI NORIO
