Patent ID: 7618030

Claim:
A screw engagement type clamping apparatus which pulls and fixes an object ( 10 ) to be fixed provided with an internal threaded hole ( 12 ) by a screw engagement force of an engaging bolt ( 45 ), comprising: an annular piston ( 21 ) inserted into a cylinder hole ( 20 ) provided in a housing ( 4 ) so as to reciprocate axially and to be prevented from rotating; a cylindrical rotating member ( 25 ) inserted into a cylindrical hole ( 24 ) of the piston ( 21 ) so as to be prevented from moving axially; a ball screw mechanism ( 28 ) provided between the piston ( 21 ) and the rotating member ( 25 ) such that raising or lowering the piston causes rotation of the rotating member; and an output rod ( 30 ) rotatably and movably axially inserted into a guide hole ( 29 ) formed in the housing ( 4 ), an input portion ( 41 ) of the output rod ( 30 ) is connected to the rotating member ( 25 ) so as to be rotated thereby, and the bolt ( 45 ) provided on a leading end portion of the output rod ( 30 ) is constructed so as to engage with the internal threaded hole ( 12 ) of the object ( 10 ) to be fixed.