Abstract: A burnishing tool includes a mandrel; and a frame fitted to the mandrel and holding balls contacting an outer peripheral surface on the mandrel. The outer peripheral surface has a contact surface with the balls. The contact surface is at a side of the outer peripheral surface which is closer to the work surface. The contact surface and the work surface have a distance therebetween in a direction normal to the work surface. A distance at a side of the mandrel closer to the processing machine and a distance at the opposite side of the mandrel have a distance difference therebetween. A diameter of the outer peripheral surface on the mandrel is set in such a way that the distance difference with the mandrel flexed during formation of the dimples becomes smaller than that before flexing of the mandrel.

Abstract: A preventive maintenance apparatus has a movable body and a water jet peening apparatus (WJP apparatus). The movable body installs a jet nozzle for driving and floating bodies on a base body. The movable body suspended in cooling water in a reactor pressure vessel jets high-pressure water from a high-pressure pump from the jet nozzle, advances in the cooling water, and is inserted into a pipe with the cooling water filled which is connected to the reactor pressure vessel. The posture of the movable body in the pipe is controlled by buoyancy adjustment of the floating bodies and the movable body can easily pass through a curve pipe portion. The high-pressure water from a high-pressure pump is jetted from jet nozzles of the WJP apparatus and for the inner surface of a vertical pipe portion, the WJP is executed.

Abstract: A drive system can be simplified and downsized, improves its operability, and can be configured to clamp or unclamp a work at an accurate drive timing. This invention is a clamp device of a drill. This invention includes a clamp collet inserted into a hole formed in the work, a mandrels inserted slidably inside the clamp collet, a piston-cylinder mechanism reciprocating the mandrels axially, and a directional valve driving a piston. The directional valve includes a forward introduction port introducing a pressured fluid for advancing a ram of the drill, and a main introduction port introducing the main pressured fluid. When the pressured fluid is introduced to the forward introduction port, it is clamped by a one-way movement of the piston.