Turntable

Claim 1

IN A MACHINE TOOL HAVING AN AUTOMATICALLY INDEXED WORK SUPPORT, AN INDEXING MECHANISM FOR ROTATING AND STOPPING SAID WORK SUPPORT STEP-BY-STEP AT SEVERAL WORK STATIONS AND AT A LOADING STATION, TOOLS MOVABLE TOWARD AND FROM AT LEAST ONE WORKPIECE ON SAID WORK SUPPORT FOR MACHINING SAID WORKPIECE WHILE SAID WORK SUPPORT IS STOPPED AT SAID WORK STATIONS, CONTROL MEANS FOR AUTOMATICALLY CONTROLLING SAID MECHANISM COMPRISING MEANS FOR EMITTING AT LEAST ONE BEAM OF LIGHT NEAR SAID LOADING STATION ALONG A PATH DISPOSED IN A POSITION SO AS TO BE BOUND TO BE INTERRUPTED BY THE OPERATOR OF THE MACHINE WHILE MOUNTING A WORKPIECE ON SAID WORK SUPPORT AT SAID LOADING STATION AND WHILE REMOVING IT THEREFROM, TIMERESPONSIVE MEANS EFFECTIVE TO KEEP SAID WORK SUPPORT STOPPED FOR THE TIME NECESSARY FOR THE COMPLETION OF THE LONGEST OPERATION OF SAID TOOLS ON SAID WORKPIECE, SAID INDEXING MECHANISM THEREAFTER NORMALLY ADVANCING SAID WORK SUPPORT BY ONE STEP, SAID CONTROL MEANS INCLUDING A CIRCUIT OF WHICH SAID TIME-RESPONSIVE MEANS FORMS A PART AND WHICH FURTHER INCLUDES LIGHT-SENSITIVE MEANS IN THE PATH OF SAID LIGHT BEAM FOR NORMALLY MAINTAINING SAID INDEXING MECHANISM OPERATIVE, SAID CIRCUIT FURTHER INCLUDING MEANS RENDERING THE INDEXING MEANS INOPERATIVE TO ROTATE THE WORK SUPPORT WHEN THE BEAM IS INTERRUPTED, SAID CIRCUIT RENDERING THE INDEXING MEANS OPERATIVE TO MOVE THE WORK SUPPORT WHEN SAID BEAM IS RESTORED AT A TIME WHEN SAID TIME-RESPONSIVE MEANS IS INEFFECTIVE.