Automatic grinding apparatus

An automatic grinding apparatus comprising:

• a constant rotating grinder comprising a grinding motor and a grinding disk actuated by said grinding motor, said grinding motor having substantially no variation in RPM due to variation of load on said grinding disk, and a load current of said motor which increases or decreases due to metal removal rate;
• an industrial robot having a wrist means thereon;
• a robot controller;
• a travelling device attached to said write means of said industrial robot and supporting said grinder for three-dimensional movement of said constant rotating grinder along a surface of a workpiece to be ground;
• a sliding device on said robot comprising an elevation motor for adjusting the distance between said grinding disk and said surface of the work piece to be ground and a slider actuated by said elevation motor and supporting said constant rotating grinder at the front surface thereof for raising and lowering said grinder, said sliding device being capable of independently actuating said travelling device;
• a programmable controller for controlling said grinder and sliding device to start and stop the control thereof, to recover to the initial start point, and to stop by receiving respective signals from said robot controller;
• timer means for generating a signal for actuating said sliding device to move said grinding disk towards the workpiece after slip current of said grinding motor becomes stable at initiation of grinding;
• detecting means outputting a driving signal to said travelling device simultaneously with or after a time delay after detecting that said disk contacts said surface to be ground due to the variation of the load current of said grinding motor;
• and
• means for recovering the relative location of said disk and said sliding device to a certain condition by regulating an actuating time of said elevation motor before and after the grinding.