Shutter actuating arrangement

Claim 1

IN A SHUTTER ACTUATING ARRANGEMENT FOR MAINTAINING A SHUTTER IN AN OPEN POSITION DEPENDING UPON THE INTENSITY AN AMBIENT LIGHT, IN COMBINATION, ACTUATING MEANS ADAPTED TO MOVE BETWEEN AN INOPERATIVE POSITION AND AN OPERATIVE POSITION IN WHICH IT MAINTAINS SAID SHUTTER IN OPEN POSITION; MEANS PERMANENTLY TENDING TO MOVE SAID ACTUATING MEANS INTO INOPERATIVE POSITION; ELECTROMAGNETIC MEANS TENDING TO MOVE SAID ACTUATING MEANS IN OPERATIVE POSITION UPON ENERGIZATION; ELECTRICAL INDICATOR MEANS ADAPTED TO INDICATE THE SUFFICIENCY OF AMBIENT ADAPTED TO EXPOSURE PURPOSES; A SHUTTER OPENING MEMBER ADAPTED TO MOVE THE SAID SHUTTER INTO SAID OPEN POSITION THEREOF; PHOTOSENSITIVE MEANS THE RESISTANCE OF WHICH VARIES WITH THE INTENSITY OF AMBIENT LIGHT; A SOURCE OF DIRECT CURRENT; AND SWITCHING MEANS COMPRISING A FIRST TRANSISTOR CONNECTED TO SAID ELECTROMAGNETIC MEANS AND SAID INDICATOR MEANS FOR OPERATING SAME; A SECOND TRANSISTOR FOR DIRVING SAID FIRST TRANSISTOR BETWEEN CONDUCTING AND NONCONDUCTING STATES, SAID ELECTROMAGNETIC MEANS AND SAID INDICATOR MEANS BEING ENERGIZABLE AND OPERABLE WHEN SAID FIRST TRANSISTOR IS IN THE CONDUCTING STATE; AND MEANS COUPLING SAID PHOTOSENSITIVE MEANS TO SAID SECOND TRANSISTOR FOR CONTROLLING THE LATTER IN RELATION TO THE INTENSITY OF THE AMBIENT LIGHT.