Tower crane with derricking jib - has slewing rings on base-plate which may be supported on rail bogies or crawler tracks

摘要

The slewing tower crane has a central tower on a baseplate, with slewing rings around the tower. A derricking jib for use when concreting extends obliquely upward from the baseplate slewing ring, being supported by ropes etc. from the tower slewing ring. The baseplate is mounted on a travel chassis. The latter can run on rails or crawler tracks, and the design allows the crane to be used for work other than the erection of high-rise buildings.