GB883911A - Improvements relating to photographic cameras - Google Patents

Abstract

883,911. Camera shutters. OPTISCHE INDUSTRIE DE OUDE DELFT. N.V. April 20, 1959 [Oct. 30, 1958], No. 13400/59. Class 98(1). A photographic camera has a focal plane shutter comprising at least two coaxial, axially spaced, adjacent, opaque circular discs differentially rotatable in a common direction about a common axis perpendicular to the focal plane each disc having at least one radial aperture extending to the periphery of the disc the aperture(s) in one disc being narrower than those in the other. In the stereoscopic camera shown, one of two films is mounted on shafts 32, 33 so that it passes over sprocket rollers 34, 35; the other film is similarly mounted in a compartment 28. These films are advanced by the rollers which are driven at a constant selected speed by an electric motor 40 through an electromagnetic coupling 47 and a worm gear 49. To drive each film at a different speed a second electromagnetic coupling and worm gear may be provided. The spindle 33 of take-up spool 30 is rotated by shaft 50 through pulleys 53, 54 and crossed belt 55. The two shutter discs 26, 25 are mounted on coaxial shafts 39, 38 respectively and are driven at differential speeds by sprocket wheels co-operating with toothed belts 43, 42 driven by the motor 40. The width of the wider aperture in disc 26 depends on whether both image areas are exposed by the apertures in the same revolution in which case the aperture is very wide or whether only one area is exposured every x rotations when the aperture can be narrower. Each disc may be provided with a second aperture and a third apertured disc may be added to vary the frequency of the exposures. This shutter is also described when incorporated in an ordinary camera and in a miniature camera. When in the latter it is spring driven as shown in Fig. 8. The spring motor comprises a drum 83 rotatably mounted on a shaft 84 and controlled by a spring 87 which may be wound up by a knob on shaft 84. When the drum rotates it drives the shaft 109 to which one of the shutter discs is attached through gear-wheel 86, 106, 103, 108 and the other shutter disc mounted coaxial with the first is similarly rotated. When a button 101 is depressed the latch 96 on arm 97 moves downwards together with the projection 95 on the arm 96 which is moved away from a pin 93 on the drum. The drum then rotates clockwise until the pin 93 pushes the arm 97 to the right thereby freeing the arm 94 which is brought back to the position shown by a spring.