X-ray timer

Claim 1

IN AN X-RAY TUBE EXPOSURE INTERVAL TIMER CIRCUIT, WHEREIN AN X-RAY TUBE MAY BE ENERGIZED DURING EXPOSURE INTERVALS CONSISTING OF A CONTINUOUS ODD OR EVEN NUMBER OF HALF CYCLES OF A POWER LINE FREQUENCY OR DURING SPACED HALF CYCLES OF ALTERNATE POLARITY, AN A.-C. POWER LINE, AN X-RAY TUBE, A STEP-UP TRANSFORMER FOR ENERGIZING THE XRAY TUBE FROM THE POWER LINE, A BRIDGE RECTIFIER COUPLING THE SECONDARY WINDING OF SAID TRANSFORMER TO SAID X-RAY TUBE THROUGH THE SAME DIRECT CURRENT PATH FOR ANY OF THE AFOREMENTIONED EXPOSURE INTERVALS, CONTACTOR MEANS IN CIRCUIT WITH THE PRIMARY WINDING OF THE TRANSFORMER, SAID CONTACTOR MEANS BEING ADAPTED TO CLOSE DURING ANY CONTINUOUS INTERVAL AND TO OPEN AT THE END THEREOF AND TO CLOSE AND OPEN FOR EACH INTERVAL CONSISTING OF SPACED HALF CYCLES OF ALTERNATE POLARITY, START RELAY MEANS FOR STARTING AN INTERVAL, A PARALLEL CIRCUIT INCLUDING MEANS SELECTIVELY CONDUCTIVE IN ACCORDANCE WITH POWER LINE POLARITY, SAID PARALLEL CIRCUIT BEING IN SERIES WITH SAID START RELAY MEANS AND CONNECTED TO A POWER LINE, TRANSFER MEANS FOR RENDERING CONDUCTIVE ONE OF SAID PARALLEL PATHS FOR ONE LINE POLARITY AND THE OTHER PATH FOR ANOTHER LINE POLARITY BEFORE AN EXPOSURE INTERVAL, A CONTROL CIRCUIT SUPPLYING SAID CONTACTOR MEANS, MEANS FOR CLOSING SAID CONTROL CIRCUIT UNDER THE CONTROL OF SAID TRANSFER MEANS FOR INITIATION OF CONDUCTION ON A POLARITY CORRESPONDING WITH THAT DURING WHICH THE START RELAY BEGINS CONDUCTING, WHEREBY SAID CONTACTOR MEANS MAY CLOSE THE CIRCUIT THROUGH THE PRIMARY WINDING OF THE TRANSFORMER WHEN THE POLARITY OF THE VOLTAGE ON THE LATTER IS OPPOSITE TO THAT AT THE END OF THE PRECEDING HALF CYCLE ENDING THE PREVIOUS INTERVAL.