Retarding device for photographic shutter

Claim 1

A RETARDING DEVICE FOR A PHOTOGRAPHIC SHUTTER HAVING OPERATING MEANS FOR OPENING AND CLOSING IT AND A MOVING ELEMENT CONNECTED TO IT CHARACTERIZED IN THAT THE EXPOSURE TIME PROVIDED BY SAID SHUTTER IS A FUNCTION OF THE SPEED OF MOVEMENT OF SAID MOVING ELEMENT, SAID RETARDING DEVICE COMPRISING A RETARDING LEVER INCLUDING DRIVEN AND RETARDED ENDS, PIVOT MEANS ROTATABLY MOUNTING SAID RETARDING LEVER WITH ITS DRIVEN END INTERPOSED IN THE PATH OF SAID MOVING ELEMENT FOR ENGAGING SAID MOVING ELEMENT TO RETARD IT AND SAID SHUTTER, A RETARDING MASS, BEARING MEANS ROTABLY MOUNTING SAID RETARDING MASS IN THE PATH OF SAID RETARDED END OF SAID RETARDING LEVER, SAID RETARDING LEVER AND MASS HAVING CONTACTING SURFACES WHICH ENGAGE EACH OTHER AT A MOMENT ARMS RELATIVE TO THEIR AXIS OF ROTATION WHICH VARY DURING THEIR CONTACTING MOVEMENT TO CAUSE THE RETARDING FORCE TRANSMITTED THROUGH SAID LEVER TO VARY DURING THE OPERATION OF SAID SHUTTER, AND CONTROL MEANS ENGAGED WITH SAID RETARDING LEVER FOR VARYING THE AMOUNT OF INITIAL INTERPOSITION OF SAID DRIVEN END OF SAID RETARDING LEVER INTO THE PATH OF SAID MOVING ELEMENT AND THE INITIAL MOMENT ARM OF SAID CONTACTING SURFACES RELATIVE TO THE AXIS OF ROTATION OF SAID RETARDING MASS AT THE BEGINNING OF SAID CONTACTING MOVEMENT TO VARY ITS RETARDING EFFECT UPON SAID SHUTTER WHEREBY SLOWER SHUTTER SPEEDS ARE PROVIDED WITH GREATER AMOUNTS OF SAID INTERPOSITION AND SMALLER INITIAL MOMENT ARMS.