Spiral extension instep arbor for use in e.g. inner gripper for clamping workpiece in e.g. turning machine, has top and bottom flanges which are expandable or shrinkable in axial directions when axial force is exerted on flanges

摘要

The arbor has top and bottom flanges which are shrunk by applying axial pressure force such that diameters of the flanges expand outward, where the top flange is provided with a coarse thread. A coarse thread spindle (2) is rigidly connected with the bottom flange, where the top flange rotates opposite to the bottom flange such that arcuate spirals move radially outward. A differential screw (7) comprising differential screw threads exerts axial force on the flanges such that the flanges are expandable or shrinkable in both axial directions. An independent claim is also included for a spiral extension clamping sleeve.