GB769070A - Improvements in or relating to photographic shutters - Google Patents

Abstract

769,070. Photographic cameras. DECKEL, H. and DECKEL, F. W. May 31, 1955 [May 31, 1954], No. 15663/55. Class 98(1) In a photographic lens shutter with which an interchangeable lens assembly with a diaphragm is associated, whereby disconnectible coupling means are provided to couple" the shutter-setting member and the diaphragm-setting member, the disconnectible coupling means are so arranged that when the lens assembly is in place, adjustment of the disconnectible coupling effects an adjustment of the setting members to different relative positions. As shown in Fig. 1, a lens shutter 10 of conventional pivoted-blade type is mounted on the front wall 12 of the camera. The time of exposure is adjusted by means of a setting ring 16 rotatably mounted on the front end of the shutter. A plate 18. clamped about the lens tube 22 of the shutter by means of a screwthreaded ring 20, has bayonet slots 24 engaging the corresponding projections 26 of a housing 28 of an interchangeable lens 30. An iris diaphragm comprising pivoted blades 33 mounted in a recess 32 within the housing 28 is adjustable by a diaphragm-setting ring 34 having a radial arm 36 projecting outwards through a slot 38 in the housing 28. A coupling ring 40 is mounted for rotation on the housing 28, and is normally urged by compression swings. 44'towards the .ring 16. The arm 36 enters a longitudinal groove 50 in the coupling ring 40, so that the diaphragmsetting ring 34 moves therewith. A tooth 46 on the, coupling ring 40 is urged by the springs 44 into one of a series of grooves on the front edge. of the ring 16. The ring 16 carries a scale 52 of exposure times and a fixed index 60, Fig. 2, while the control ring 40 carries a scale 56 of diaphragm apertures and a scale 58 of light values. To set shutter speed and .exposure time, the ring 40 is pulled forward to disengage tooth 46 from the ring 16, and is turned relatively to ring 16 to set the light value on scale 58 opposite the mark 40 in accordance with the light conditions prevailing; or alternatively the rings are so arranged that a given aperture value and shutter speed are set opposite one another on the scales 56. 52. Ring 40 is then released, and tooth 46 is urged by springs 44 into engagement with the ring 16. The rings 40, 16 are then rotated 'together until a desired combination of shutter speed and diaphragm aperture appear opposite a fixed index 54.