Patent ID: 7367238

Claim:
A method of clamping a bar, comprising: providing a collet assembly having a housing; a piston disposed within the housing, the piston defining a bore; and a collet disposed within the bore defined by the piston, the collet having a base and fingers which define a center bore extending along a longitudinal axis; extending the bar through the center bore of the collet that extends along the longitudinal axis; moving the piston from a first position to the second position in a direction along the longitudinal axis; moving a plurality of ball bearings disposed between the piston and the fingers of the collet longitudinal and radially inward towards the longtitudinal axis by the movement of the piston from the first position and the second position along the longitudinal axis and a second position along the longitudinal axis; and clamping the bar by the fingers of the collet deflected radially inward by the ball bearings; wherein each finger of the collet has a finger ball channel, the finger ball channels of the fingers being angled such that the finger ball channels are further from the longitudinal axis at a distal end than at the base, the bore defined by the piston having a plurality of piston ball channels, the collet being received in the bore of the piston of the collet assembly such that the finger ball channel of each finger of the collet aligns with a piston ball channel of the piston, the piston ball channels of the piston angled such that the piston ball channels are further from the longitudinal axis at an end closer to the distal end of the fingers of the collet, and the plurality of ball bearings interposed in the ball channels between the collet and the piston to provide movement of the piston along the longitudinal axis towards the distal end of the fingers to force the ball bearings to compress the fingers of the collet to clamp the torsion bar; and wherein moving the plurality of ball bearings includes deflecting the plurality of ball bearings along the ball channels between the collet and the piston.