Patent ID: 8302789

Claim:
A rotating superstructure, comprising: a front block on which is arranged a power unit that includes a prime mover; and a rear block on which is arranged a unit for raising and lowering a boom that includes a winch and a sheave, wherein: the rotating superstructure is configured to be split into the front block and the rear block; a first abutment section having a first abutment surface is provided at an end of the front block at a side joining with the rear block, the first abutment section being a plate-like member; a second abutment section having a second abutment surface is provided at an end of the rear block at a side joining with the front block, the second abutment section being a plate-like member; and when the front block and the rear block are joined together, the first abutment surface of the first abutment section and the second abutment surface of the second abutment section contact each other in face contact to receive compressive forces.