Patent ID: 7036409

Claim:
Spring collet for use within a spindle assembly of machine tools and automatic lathes configured for machining high-precision parts, wherein: the spring collet has an axis and concentrically aligned thereto, a variable central axial opening adjustable to a first open position and to a second closed position, for respectively, releasing and clamping a workpiece, the spring collet having at least two grooves, where each one of the two grooves has two mutually opposite faces, a collar extending concentrically outward from the spring collet, and having a tapering surface against which rests a corresponding face of a sleeve operable for translating forth and back along a limited axial course length c, to reversibly dispose the variable central axial opening, respectively, in the open and in the closed position, and an axial length λ of the collar being retained within a length interval whose lower and upper limits are about, respectively, twice and five times the axial course length c, comprising: the tapering surface being inclined by about 45° relative to the axis of the spring collet.