GB864601A - Shutters for photographic cameras - Google Patents

Abstract

864,601. Photographic shutters. VOIGTLANDER A.G. Sept. 23, 1957 [Sept. 22, 1956], No. 29841/57. Class 98(1) A centrally opening photographic shutter of the roller blind type is characterized in that blind is an endless band disposed in front of the film and behind at least one lens element, passing around rollers disposed on opposite sides of the light path and having openings which overlap in the region of the light path to allow the passage of light. As shown, the band 1 passing over rollers 6, 7, 8 and 9, has apertures 2 and 3 which-on rotation of the rollers-may be brought into coincidence with light path halfway between the rollers 8 and 9. The rollers 6 and 7 have teeth 23 which engage apertures 22 of the band to obviate slipping. To the spindle of the roller 6 is attached a gear wheel 39 which meshes with a driving wheel 40 to which is fastened a locking disc 41 and both members are freely mounted on a shaft 42 to which one end of a spring 43 is anchored-the other resting on the disc 41. On the disc 41 is a lug 44 which co-operates with abutments 45, 46 on a slide 47 manually displaceable by means of the button 49 and urged upward by spring 50. The end 61 of the shaft 42 is connected to the camera film winding mechanism so that during winding the spring 43 is tensioned but the disc 41 held from rotation by the lug 45. On depression of the button 49 the disc 41 is released and the roller 6 is driven by the wheels 39 and 40 to rotate the blind 1. The motion continues until the lug 44 abuts the member 46. Variation of exposure is effected by the lug 44 engaging the arm 52 of a braking mechanism for part of its rotation predetermined by means of a setting member 55 co-operating with a cam 54. In another embodiment, there are no braking means and the torsion drive mechanism is incorporated within one of the rollers.