PURPOSE: To enable holding mechanisms to exhibit a great bridging force through a simple structure by having a direction changing mechanism that converts displacement of the spindle of a main cylinder into displacement perpendicular thereto and a toggle mechanism, and causing a plurality of bridging arms to expand and contract in the radial direction of piping.
CONSTITUTION: A reverse side bead removal system which grinds reverse side by running inside the piping 1 of a nuclear power plant or the like has an in-pipe travel device connected to the rear of a grinding device along the direction in which the grinding device moves, with in-pipe holding mechanisms 13 provided at the front and rear of the in-pipe travel device along the direction in which the travel device moves. The in-pipe holding mechanisms 13 each have a main cylinder 21 disposed approximately in the center of the inside of a main body casing 20 and along the direction of the axis of the piping, and the displacement of the spindle 21a of the main cylinder 21 in the direction of the piping axis is converted into the displacement of a supporting block 31 in the direction of the piping axis by a direction changing mechanism 22 that utilizes a wedge mechanism. By operation of a toggle mechanism 33 supported against the supporting block 31, bridging arms 32 mounted on the supporting block 31 are pressed into contact with the inner surface 1a of the piping, and thus the in-pipe travel device can be held inside the piping.
SATOU TERUAKI
SAITO KAZUO
ONO MITSUO
NAKAMURA MANABU
TOSHIBA CORP
ISHIKAWAJIMA HARIMA HEAVY IND
ISHIKAWAJIMA INSPECTION & INST