Patent GB-689511-A (GB)
Title: Improvements in or relating to film holders for photographic cameras
Inventor: TAIT WILFRED ELIOT
IPC: G03B17/26
Filed: 1950-11-01
Abstract: 689,511. Photographic cameras. AMERICAN SAFETY RAZOR CORPORATION. Nov. 1, 1950, No. 26665/50. Class 98 (i). A disc-shaped filmholder for a photographic camera includes a film-carrying base, a cover rotatably mounted on the base and provided with an aperture normally closed by a shutter, the aperture overlying the film carried by the base whereby successive sections of the film are brought under the aperture on rotation of the cover, means adjacent to the aperture for detachably securing a lens and shutter mounting to the cover, and means engageable by the mounting or its attachment to the cover to open the shutter, the base having an edge extending beyond the edge of the film, and the cover being rotatably secured to the base by means of a U-sectioned clamping strip embracing the edges of the base and cover. The camera consists of two separable parts: a disc-like film holder, and a mount for a lens, shutter, and view-finder. The film-holder is shown in exploded view in Fig. 11, and has a circular base 25 having a central square boss 26, a shallow circular depression 28, and a deeper circular depression 29 bounded by a turned-over edge 31. Step-like raised portions 30 are formed within the depression 29. A circular piece of photographic film 27 lies on the base 25 with its edge overlying the depression 28 and with the boss 26 passing through a square aperture in the film. A ring 32 lies over the film, and has a number (e.g. four) of projections 33 which enter between adjacent raised portions 30 to hold the ring against rotation. The ring also has a number of fingers 34, formed with bent ends 35 and sprung outward from ring 32. The film-holder cover consists of three discs. The outermost disc 42 has a central circular aperture 48, and an off-centre flanged aperture 50 forming an attachment for the lens mount. The next disc 43 has a boss 53 fitting loosely in aperture 48 and formed with an aperture 54 of oval shape, and an aperture 52 at one side. The third disc 41 has a central circular aperture 47 and a rectangular picture-defining aperture 49 at one side. Disc 42 has its edge 45 turned over to grip the edge of disc 41, disc 43 being rotatable between them. The three discs are placed over ring 32 and held in position by a knurled ring 37 fitting over the edge 31 of the base. Discs 41, 42 have registering peripheral notches, equal in number to the number of exposures to be made on one film, which coact with fingers 34. Aperture 49 in disc 41 is in register with aperture 50 of disc 42, but aperture 52 of disc 43 is out of register therewith so that no light can reach film 27. A boss 55, Fig. 3, has a rearward projection 57 fitting into aperture 54 in disc 43 and is formed with a large tooth 61 and a series of smaller teeth 60. A mount 21, carrying a lens and shutter in a housing 23, and a direct-vision view-finder 22, can be inserted in a bayonet attachment on the flange surrounding aperture 50 in disc 42. Mount 21 has a large tooth 63 and smaller teeth 64. The mount is inserted with these teeth in register with a mark on disc 42, and; when the mount is turned to secure the bayonet joint, the teeth on the mount engage the teeth on boss 55 to rotate disc 43 until tooth 63 abuts a stop 68 and aperture 52 registers with apertures 50, 49. A photograph may then be made on part of film 27. Discs 41, 42, 43 are turned by hand with respect to ring 37, base 25, film 27, and ring 32 until a fresh area of film is in register with the aperture 49. This is indicated by an arrow on the disc 42 which indicates numbers marked on ring 37, and by fingers 34 which clock into the peripheral notches on discs 41, 42. These fingers also prevent reverse rotation of the parts. A projection on ring 37 meets the flange for the mount 27 when the film is completely exposed, so that the parts cannot be rotated further. The mount is removed, turning disc 43 so that its aperture 52 returns to its previous position. The film-holder may then be posted to a central depot for development of the exposed film and for re-loading. Two cassettes may be welded together back-to-back, and may be loaded with different kinds of film. Specifications 674,849 and 685,388 are referred to.