PURPOSE: To provide a polished surface of excellent quality by surely polishing the inner surface of a bent tube.
CONSTITUTION: In an equipment for polishing the inner surface of a bent tube to polish the inner surface 1a of a bent tube 1 with a polishing material 3 fitted to a polishing tool 4 by inserting the polishing tool 4 connected to the tip part of a main spindle 2 into the bent tube 1 and moving the tool in the longitudinal direction while being rotated, the polishing tool 4 is connected to the main spindle 2 through a coil spring 5, and an expansion restricting mechanism 6 to restrict the expansion of the coil spring is provided in the coil spring 5. The expansion suppressing mechanism 6 consists of a ball joint 6A, and the coil spring 5 is kept in the tense condition by interposing the ball joint 6A between the polishing tool 4 in the coil spring 5 and the main spindle 2.
TAMIYA KATSUTSUNE
NAKAGAWA SHIGEKI
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