Repair device

A repair device that repairs a welded part on an inner peripheral side of a pipe, comprising:

• a casing;
• a slide shaft slidably arranged with respect to the casing;
• a turn table rotatably arranged with respect to the slide shaft;
• and
• a cutting mechanism installed on the turn table and including a plurality of cutting tools for cutting the welded part, wherein
• the turn table is rotationally displaced while the slide shaft slides in an axial direction, so that the cutting tools helically turn to cut an inner periphery of the pipe, and
• the cutting mechanism includes a cutting-tool switching unit that switches the cutting tools,
• the cutting-tool switching unit includes a switching-unit main body installed on a side of the turn table, a cutting-tool support body that supports the cutting tools and switches the cutting tools by a rotational displacement, a fitted rotating shaft that is connected to the cutting-tool support body, and a drive mechanism that is connected to the fitted rotating shaft via a ratchet mechanism, and
• the ratchet mechanism engages to rotate the fitted rotating shaft when the drive mechanism is driven in a predetermined forward direction, and the ratchet mechanism restricts rotations of the fitted rotating shaft when the drive mechanism is driven in an opposite direction.