Shutter mechanism

Claim 1

IN A PHOTOGRAPHIC CAMERA, FOCAL PLANE SHUTTER MECHANISM FOR EFFECTING AN EXPOSURE THROUGH A PICTURE WINDOW FORMED IN THE FRAME OF SAID CAMERA, COMPRISING: FIRST AND SECOND BLADE GROUPS EACH CONSISTING OF A MAIN AND A SUBSIDIARY BLADE, EACH OF SAID MAIN AND SUBSIDIARY BLADES CARRIED BY RESPECTIVE DRIVING LEVERS PIVOTED ON SAID FRAME AT ONE SIDE OF SAID PICTURE WINDOW, WHEREBY UPON MOVEMENT OF SAID LEVERS FOR AN EXPOSURE SAID BLADE GROUPS TRAVEL LINEARLY ACROSS SAID PICTURE WINDOW IN THE TRANSVERSE DIRECTION TO THE LENGTH THEREOF; FIRST SPRING MEANS OF SUBSTANTIALLY S-SHAPE SECURED AT ITS CENTER TO SAID FRAME AT SAID ONE SIDE THEREOF AND HAVING ITS OPPOSITE FREE ENDS BEARING AGAINST SAID MAIN BLADE DRIVING LEVERS RESPECTIVELY; A GUIDE SHAFT MOUNTED ON SAID FRAME AT SAID ONE SIDE THEREOF AND EXTENDING IN THE DIRECTION OF MOVEMENT OF SAID BLADE GROUPS; A SHAFT CO-AXIALLY SURROUNDING SAID GUIDE SHAFT AND MOVABLE AXIALLY THEREOF; SECOND SPRING MEANS BIASING SAID MOVABLE SHAFT TO A RELEASED POSITION; SAID MOVABLE SHAFT ALSO HAVING A PAIR OF SHOULDERS POSITIONED THEREON IN SPACED RELATIONSHIP, SAID SHOULDERS SIMULTANEOUSLY ENGAGING SAID SUBSIDIARY BLADE DRIVING LEVERS RESPECTIVELY TO SET SAID BLADE GROUPS IN A CHARGED-UP POSITION AGAINST THE FORCE OF SAID WIRE SPRINGS; AN ARRESTING LEVER ENGAGEABLE WITH SAID SUBSIDIARY BLADE DRIVING LEVER OF SAID SECOND BLADE GROUP WHEN SAID BLADE GROUP IS IN THE CHARGED-UP POSITION; HOLDING MEANS FOR HOLDING SAID AXIALLY MOVABLE SHAFT IN THE CHARGED-UP POSITION AGAINST THE FORCE OF SAID SECOND WIRE SPRING; AND MEANS FOR RELEASING SAID HOLDING MEANS THEREBY RELEASING SAID MOVABLE SHAFT FROM SAID CHARGED-UP POSITION WHEREBY SAID SHOULDERS DISENGAGE FROM SAID SUBSIDIARY BLADE DRIVING LEVERS CAUSING SAID SUBSIDIARY BLADE DRIVING LEVER OF SAID FIRST BLADE GROUP TO DRIVE GROUP ACROSS SAID PICTURE WINDOW AND THEREAFTER SAID MOVABLE SHAFT ENGAGES SAID ARRESTING LEVER TO DISENGAGE SAID ARRESTING LEVER FROM SAID SUBSIDIARY BLADE DRIVING LEVER OF THE SECOND BLADE GROUP CAUSING SAID SUBSIDIARY BLADE DRIVING LEVER TO DRIVE SAID SECOND BLADE GROUP ACROSS SAID PICTURE WINDOW FOLLOWING SAID FIRST BLADE GROUP.