Timing mechanism for photographic shutters

Abstract

Timing mechanism for timing an adjustable and controlled interval between commencement of movement of two light obstructing elements of a photographic shutter, such as commencement of movement of an opening blade or curtain, and subsequent commencement of movement of a closing blade or curtain. A cam operatively connected to the first element starts to move upon the movement of that element, and controls the movement of a first pivoted lever. There is a second pivoted lever spaced from the first pivoted lever and adapted to be moved from the movement of the first lever, through an intermediate adjusting member which is moved by the movement of the first lever and which, in turn, causes movement of the second lever. For adjusting the time interval, the adjusting member is movable toward or away from the fulcrum of the first lever, and simultaneously away from or toward the fulcrum of the second lever, thereby varying the transmission ratio from one lever to the other. Predetermined movement of the second lever releases a release member, whereupon movement of the second or trailing shutter element commences. Provision is made for moving the second lever to an inoperative position, whenever it is desired to control the time interval automatically by electronic means, rather than by the mechanical lever system. The invention is particularly useful in connection with shutters of the focal plane type.