Patent ID: 7140818
Filing Date: 2006-11-28
Classification: B23Q,Y10T

Abstract:
1. A machine tool comprising: a machine tool body provided with a spindle, a driving means for driving said spindle, and at least one control axis for changing a relative position between said spindle and a workpiece; a control apparatus for driving and controlling said driving means and control axis in accordance with a machining program; a tool attachable to said spindle and provided with a machining tool for machining a workpiece, a motor for driving said machining tool, a generator for generating electric power by the rotation of said spindle, a light signal generation means for generating a light signal in accordance with the rotational speed of said motor, and a light guiding means for guiding light into said light signal generation means from outside to output the light signal by said light signal generation means to the outside; a light receiving and emitting means for emitting light to said light guiding means without contact and receiving said light signal without contact; and a rotational speed detecting means for detecting the rotational speed of said motor based on said received light signal.