GB585691A - Improvements in or relating to photographic shutters - Google Patents

Abstract

585,691. Photographic shutters. TAYLOR, TAYLOR, & HOBSON, Ltd., and CLIFFORD, T. W. Feb. 26, 1945, No. 4798. [Class 98 (i)] In a pivoted blade symmetrical opening shutter, each pivot pin constitutes the pivot of a set of superimposed blades whose operating studs lie at different distances from the pivot pin so that upon operation of the blade-operating member the blades of each set move respectively through different distances. For an increasing number of blades in each set, the slots have to be correspondingly larger. The front body of the shutter assembly carries a fixed blade pivot ring with pivot pins E<4>, and a blade-operating ring, F carrying studs F<1>, F<2> is angularly adjustable thereon. The blades are in pairs E<1>, E2, the studs F<1>, F<2> being offset and lying at different radial distances from the main axis O. The stud F<1> extends through an elongated slot F<3> of the lower blade E<1> and through an opening F<4> in the upper blade E<2>. The second stud F<2> extends through different parts of the openings F<3>, F<4>, which are so shaped (roughly L-shaped) that pivotal movement of one blade does not interfere with that of the other blade. In the fully-open position of the shutter, the two sets of blades are superimposed so that the annular space accommodating the blades is roughly equal to their width. Movement of the ring F swings the lower blade E<1> further than the other blade E<2>, and the two blades cover different areas of the aperture. Widening and/or thickening of the blades E<1>, E<2> at their pivot ends enables the pivot pins E<4> to be positioned to engage the blades at or near their centres of gravity. Specification 585,690 is referred to.