GB312877A - Improvements in or relating to shutter mechanism for photographic apparatus - Google Patents

Abstract

312,877. Hart, S., and Stealey, J. I. Sept.. 5, 1928. Shutters with sliding plates, and with pivoting or rotating blades or discs.- Shutter mechanism comprises a shutter member or members, spring or otherwise influenced to tend to assume the closed position, and a solenoid coil with a soft iron armature. The energizing of the solenoid coil magnetically attaches the shutter to the armature and moves it to cause the opening of the lens aperture. Subsequently the shutter is automatically separated from the armature and returns to the closed position. In the form shown, a sliding plate 14 having a stem 15 with a piece of soft iron 18 at its upper end closes the aperture 12. The energizing of the solenoid (not shown) lifts the armature 20 together with the plate 14 until the latter, striking the stops 19, is separated from the armature and falls into the closed position. When the energization of the solenoid ceases, the armature falls, a rubber buffer 21 preventing jarring. Engagement between the shutter and the stops 19 may be made to break the solenoid circuit temporarily. The time of exposure may be altered by adjusting the stops 19, by providing adjustable return springs for the shutter, by suitably controlling the electrical circuit of the solenoid or by using shutter plates with apertures of differing size. The shutter proper may comprise a rotating disc or blade or a pair of plates operating through toggle lever mechanism.