To facilitate recycling of a body frame, etc., by forming a long hole for penetrating a fastening member to be fastened to a first fastening object, and forming a plurality of fastening holes on a second fastening object for the fastening member.

In order to fasten an angle 43 to a fastening position of a main body frame 40, a positioning boss 45 is fitted to a positioning hole 42 of the frame 40. A screw 47 penetrates through a fastening long hole 41 of the frame 40, and is fastened to a center hole among three screw holes 44 of the angle 43. One use of the center hole 44 is recorded in a record area 46 of the angle 43. Each use of the center hole 44 is stored at the time of assembling after disassembling required by maintenance and mending. When the screw thread of the center screw hole 44 is crushed, the screw 47 is slid through the long hole 41 and fastened to the unused screw hole 44. One use thereof is also recorded. Number of operation cycles is not increased by recycling, and recycling itself is facilitated.