Surface grinding machines

Claim 1

IN A SURFACE GRINDING MACHINE COMPRISING A WORK TABLE, A FIXED COLUMN, A WHEELHEAD MOUNTED IN SAID COLUMN AND DISPLACEABLE TOWARDS AND AWAY FROM SAID WORK TABLE, A MOTOR, FEED MEANS ASSOCIATED WITH SAID MOTOR FOR DISPLACING SAID WHEELHEAD, AND A GRINDING WHEEL MOUNTED IN SAID WHEELHEAD, THE COMBINATION OF MEANS FOR AUTOMATICALLY TERMINATING THE FEED DISPLACEMENT OF SAID WHEELHEAD TOWARDS SAID WORK TABLE, WITH REGARD TO THE PROGRESS OF WEAR OF THE WORKING SURFACE OF SAID GRINDING WHEEL, WHEN SAID WORKING SURFACE IS AT A PREDETERMINED DISTANCE FROM THE WORK TABLE, SAID MEANS COMPRISING A SLIDEWACE FROM THE WORK TABLE, SAID MEANS COMPLACEABLE IN SAID SLIDEWAY IN THE DIRECTION OF MOVEMENT OF THE WHEELHEAD, A POROBE PIVOTALLY MOUNTED ON SAID SLIDE AND PROJECTING TOWARDS THE WORK TABLE, A MAGNIFYING LEVER ENGAGED WITH SAID PROBE AND DISPLACEABLE WHEN THE PROBE ENGAGES A WORKPIECE, A CONTROL SWITCH ACTUABLE BY SAID MAGNIFYING LEVER, MEANS FOR DISPLACING SAID SLIDE WITH RESPECT TO THE SLIDEWAY, AN AUXILIARY MOTOR OPERABLE BY SAID CONTROL SWITCH WHEN ACTUATED TO MOVE SAID DISPLACING MEANS TO DISPLACE SAID SLIDE AWAY FROM SAID WORK TABLE, A FEED STOP SWITCH IN CIRCUIT WITH SAID MOTOR, AND A TRIP CAM CARRIED BY SAID SLIDE TO BE DISPLACEABLE THEREWITH, SAID TRIP CAM SERVING TO ACTUATE SAID FEED STOP SWITCH.