GB592537A - View-finders and shutters for motion picture cameras - Google Patents

Abstract

592,537. Combined shutters and view finders for kinematograph cameras. WEISSBRODT, J., and BROIDO, J. J. April 11, 1945, No. 9062. Convention date, July 4, 1941. [Class 97 (i)] The combination comprises a shutter made in two parts lying face to face-the part nearer the objective carrying a reflector inclined to the optical axis of the camera and the other part an aperture identical with the exposure aperture-reciprocable out of phase with one another across the exposure aperture so that in turn the exposure aperture is uncovered to allow the formation of an image on the film and is then covered, in which position of the parts the reflector projects an image on to the screen of a view-finder. As shown, one shutter part consists of a rectangular plate 1 having an aperture 1a and a forked extension 1b and the other of a plate 2 having an aperture 2a and an extension provided with an aperture 2b which is slightly larger than the exposure aperture 14. The plates are supported face to face by slideways 3, 4 on the frame of the apparatus. A driven shaft 11 perpendicular to the plane of the shutter carries two cams 9, 10 which engage the apertures 1a, 2a in the shutter plates, the cams being preferably independently mounted as by securing one to a sleeve having two diametrically opposed longitudinal slots engaging a cross-pin on the shaft, and the other to an outer sleeve having a pair of helical slots in which are engaged the outer ends of the same pin on the shaft, so that by displacing the shaft axially, the angle between the cams and hence the exposure time may be altered. Plate 1 carries between its aperture and fork a reflector 5 arranged at an angle to the optical axis which, when carried by the plate into position on said axis, reflects the light from the objective to form an image on a view-finder screen 7 observable either directly or by a lens 8. Under the action of the cams, the shutter plates perform the following cycle of operations : starting with the shutter open when aperture 2b coincides with the exposure aperture 14 and prism 5 is withdrawn from the line of sight, (1) plate 1 is displaced across, and covers, the aperture 14 when the prism produces an image in the view-finder ; (2) plate 2 is displaced so that its opaque end also covers the aperture 14 ; (3) plate 1 is withdrawn leaving the aperture covered by the end of plate 2 ; and (4) plate 2 is withdrawn so that apertures 2b and 14 coincide, exposing the film.