Vacuum blanket and focusing means for exposure device

Claim 1

IN A VACUUM FRAME TYPE OF EXPOSURE DEVICE, THE COMBINATION INCLUDING A VACUUM FRAME MOVABLE INTO AND FROM AN OPERATIVE POSITION, A SOURCE OF RADIANT ENERGY MOUNTED FOR RECIPROCATING MOVEMENT WITH RESPECT TO THE FRAME BETWEEN TWO TERMINAL POSITIONS, DRIVING MEANS FOR EFFECTING MOVEMENT OF THE RADIANT ENERGY SOURCE, A VACUUM PUMP FOR PRODUCING A VACUUM WITHIN THE FRAME UPON OPERATION OF THE PUMP, A PRESSURE RESPONSIVE SWITCH HAVING A CLOSING ACTION WHEN A PREDETERMINED VACUUM EXISTS IN THE VACUUM FRAME, A TERMINAL SWITCH LOCATED AT EACH TERMINAL POSITION AND BEING ACTUATED TO CLOSE BY MOVEMENT OF THE RADIANT ENERGY SOURCE INTO THE SAID TERMINAL POSITIONS RESPECTIVELY, AND CONTROL MEANS INCLUDING A UNIDIRECTIONAL RELAY, A REVERSING RELAY FOR THE SAID DRIVING MEANS, A MASTER RELAY, AND A COVER SWITCH ACTUATED INTO A CLOSED POSITION BY MOVEMENT OF THE VACUUM FRAME INTO AN OPERATIVE POSITION, A FIRST CIRCUIT INCLUDING SAID UNIDIRECTIONAL AND REVERSING RELAYS AND ONE OF THE TERMINAL SWITCHES AND BEING CONNECTED IN SERIES WITH THE COVER SWITCH, A SECOND CIRCUIT INCLUDING THE MASTER RELAY, THE OTHER TERMINAL SWITCH AND A NORMALLY OPEN CONTACTOR WHICH IS CAUSED TO CLOSE UPON ENERGIZATION OF THE UNIDIRECTIONAL RELAY, SAID SECOND CIRCUIT BEING CONNECTED IN SERIES WITH THE PRESSURE RESPONSIVE SWITCH AND THE COVER SWITCH, AND A HOLDING CIRCUIT FOR THE UNIDIRECTIONAL AND REVERSING RELAYS, SAID HOLDING CIRCUIT CONNECTING THE FIRST AND SECOND CIRCUITS AND INCLUDING THE SAID CONTACTOR, THE PRESSURE RESPONSIVE SWITCH AND THE COVER SWITCH.