Patent ID: 6394437
Filing Date: 2002-05-28
Classification: B25B,Y10T

Abstract:
A clamping apparatus comprising:a cylinder portion (13) having a first end wall (15) and a second end wall (16); an annular piston (120) having a push surface (37) and inserted into the cylinder portion (13) axially movably and hermetically; a first chamber (21) having a driving means (47), and formed between the first end wall (15) and the piston (20); a second chamber (22) formed between the second end wall (16) and the piston (20) so that pressurized fluid is supplied to the second chamber (22) and is discharged therefrom; an output rod (26) having a first end (26a) and arranged substantially concentrically with the piston (20), the output rod (26) being axially movably and hermetically inserted into the second end wall (16); a first pressure receiving member (31) and a second pressure receiving member (32) axially opposing to each other in an annular space defined between the piston (20) and the output rod (26) within the second chamber (22), the first pressure receiving member (31) and the second pressure receiving member (32) being connected to the first end (26a) of the output rod (26) and to the second end wall (16), respectively; an annular engaging space (33) formed between the first pressure receiving member (31) and the second pressure receiving member (32) so that it narrows radially inwards; and a plurality of engaging members (34) inserted into the engaging space (33) and spaced apart from each other peripherally at a predetermined interval, the driving means (47) driving the piston (20) toward the second end wall (16), thereby enabling the push surface (37) of the piston (20) to drive the output rod (26) toward the first end wall (15) through the engaging members (34) and the first pressure receiving member (31) in the mentioned order and on the other hand, the pressurized fluid, when it is supplied to the second chamber (22), driving the piston (20) to return it toward the first end wall (15) and the output rod (26) to return it toward the second end wall (16).