Patent ID: 6497417
Filing Date: 2002-12-24
Classification: B23B,Y10T

Abstract:
A collet chuck comprising:a tubular body having a front end and a rear end; a rotating shaft assembly journalled within said tubular body, and including an outer sleeve and an inner sleeve that defines a frustoconical recess ,said outer sleeve being sleeved fixedly on said inner sleeve; a belt pulley sleeved fixedly on said rotating shaft assembly; a collet disposed operably within said frustoconical recess in said inner sleeve and adapted to hold a rod-shaped workpiece therewithin; a movable member mounted axially and movably within said tubular body and movable within said tubular body in a selected one of a tightening direction and a loosening direction; and two ball bearings disposed between said tubular body and said outer sleeve so as to facilitate rotation of said rotating shaft assembly within said tubular body, said ball bearings being spaced apart from said inner sleeve so as to prevent said movable member from contact with said ball bearings during movement of said movable member in said tubular body; said tubular body further having a front oil chamber formed between said inner and outer sleeves and located immediately in front of said movable member, a rear oil chamber formed between said inner and outer sleeves and located immediately behind said movable member, a first oil passage formed in an assembly of said outer sleeve and said tubular body and in fluid communication with said front oil chamber so that hydraulic oil can be fed to said front oil chamber therethrough, thereby moving said movable member rearward within said tubular body, and a second oil passage formed in the assembly of said outer sleeve and said tubular body and in fluid communication with said rear oil chamber so that hydraulic oil can be fed to said rear oil chamber therethrough, thereby moving said movable member forward within said tubular body; wherein movement of said movable member in said tightening direction is one of forward and rearward movements of said movable member within said tubular body and results in further movement of said collet into said frustoconical recess in said inner sleeve for compressing said collet, and wherein movement of said movable member in said loosening direction is the other one of said forward and rearward movements of said movable member and results in movement of said collet away from said frustoconical recess in said inner sleeve so as to be adapted to release the workpiece from said collet.