Patent ID: 6113086
Filing Date: 2000-09-05
Classification: B25B

Abstract:
A rotary clamping apparatus comprising:a housing (1) having a first end wall (1a) and a second end wall (1b);an annular piston (4) provided with a through-hole (4a) and inserted into the housing (1) axially movably but unrotatably;a first chamber (11) formed between the first end wall (1a) and the piston (4);a second chamber (12) formed between the second end wall (1b) and the piston (4), a pressurized fluid being supplied to and discharged from the second chamber (12);a clamp rod (9) having an input portion (9a) for clamping and an input portion (9c) for rotation and hermetically inserted into the through-hole (4a) of the piston (4), the input portion (9a) for clamping being projected into the second chamber (12);a clamping spring (20) mounted in the first chamber (11) for urging the piston (4) toward the second end wall (1b);a converting mechanism (21) provided between the input portion (9c) for rotation and the piston (4) so as to convert an axial movement of the piston (4) to a rotary movement of the clamp rod (9);a stopper (23) for preventing the input portion (9a) for clamping from moving toward the first end wall (1a); anda pushing means (P) for pushing the input portion (9a) for clamping to the stopper (23).