Indexing apparatus for marking devices and the like

Claim 1

AN INDEXING APPARATUS COMPRISING AN INDEXING GEAR, A PAWL MECHANISM MOVABLE BETWEEN TWO POSITIONS ENGAGING THE INDEXING GEAR IN ONE DIRECTION OF MOVEMENT ONLY TO ROTATE THE GEAR INCREMENTALLY, A FLUID MOTOR INCLUDING A RECIPROCATING PISTON AND A ROD, THE ROD EXTENDING BEYOND THE MOTOR AND CONNECTED TO THE PAWL MECHANISM FOR IMPARTING RECTILINEAR MOTION THERETO, A FLUID SLIDE VALVE HAVING A RECIPROCATING SLIDE ELEMENT THEREIN, ARMATURES CONNECTED TO THE SLIDE ELEMENT FOR MOVEMENT THEREWITH AND EXTENDING BEYOND THE VALVE AT OPPOSITE ENDS OF THE SLIDE ELEMENT, CONDUITS FLOW-CONNECTING THE FLUID SLIDE VALVE WITH THE MOTOR FOR INTRODUCING FLUID FROM THE VALVE TO OPERATE THE MOTOR PISTON SELECTIVELY FROM ONE POSITION TO ANOTHER WHEREBY THE MOTOR PISTON ROD IS RECIPROCATED, SOLENOID COILS CONNECTED IN PARALLEL AND COUPLED MAGNETICALLY TO EACH OF THE ARMATURES, A SOURCE OF CURRENT CONNECTED TO EACH OF THE SOLENOID COILS, A SWITCH CONNECTED IN SERIES WITH EACH OF THE SOLENOID COILS AND THE SOURCE OF CURRENT, BOTH SWITCHES BEING NORMALLY OPEN AND POSITIONED FOR TRIPPING ALTERNATELY BY TRAVEL OF THE PAWL MECHANISM SUCH THAT THE COILS ARE ENERGIZED ALTERNATELY TO MOVE THE SLIDE ELEMENT OF THE VALVE FOR CONTROLLED MOVEMENT OF THE MOTOR PISTON BY FLUID PORTED FROM THE VALVE SELECTIVELY ON BOTH SIDES OF THE PISTON, A RELAY WITH A CONTACTOR CONNECTED IN SERIES BETWEEN THE CURRENT SOURCE AND THE SWITCHES AND WITH A COIL FOR OPERATING THE CON-