Patent GB-684916-A (GB)
Title: Improvements in or relating to roll-film photographic copying cameras
IPC: G03B27/58
Filed: 1949-11-29
Abstract: 684,916. Photographic copying cameras. ANDERSSON, A. V. H. Nov. 29, 1949, No. 30658/49. [A Specification was laid open to inspection under Sect. 91 of the Acts, May 31, 1950.] Classes 97 (i) and 98 (i). A roll-film photographic copying camera comprising a device for variably screening the image gate, a preferably spring-actuated mechanism for feeding the film after exposure of that part of the film under the image gate, and a control mechanism for controlling the amount of feed of the film, is characterised by the inclusion of a displaceable blind which screens more or less of the image gate, a handle for operating the blind, and an operative connection between the handle and a member of the control mechanism, such that the member can be displaced to regulate the feed of the film by an amount equal to the displacement of the blind. A gear-wheel 4, Fig. 1, loosely mounted on the shaft has a projection 3 urged against a pin H on the shaft by a coil spring 5, fixed at its ends to the shaft and to the wheel 4. A catch 2, shaped as shown, is loosely pivoted to the shaft, and has a nose engaging a wheel 11 forming part of a clockwork film-winding mechanism. A gear-wheel 7 fast with a sprocket engaging the film perforations is loosely mounted on a shaft to which a plate 8, carrying a rotatable wheel 9 in mesh with wheel 7, is also pivoted. A spring 12 acts on catch 2 and plate 8 to hold a projection 10 on the plate against a shoulder on the catch so that gearwheels 4, 9 are out of mesh. When an exposure is made, the shutter actuating means rocks an arm 15 which yields to ride over plate 8. As the arm returns by action of a spring 17, it first rocks plate 8 by camming action on its lower edge until wheels 4, 9 mesh together, and then rocks catch 2 to raise its nose and freewheel 11 so that the film is wound. Projection 10 engages a second shoulder on catch 2. The movement of the film turns the sprocket and the wheel 7, which drives wheels 9, 4 until a projection 3 on wheel 4 meets a projection 1 on catch 2, moving the catch to free its shoulder from projection 10, whereupon plate 8 and catch 2 are returned to their original positions by spring 12, catch 2 re-engaging wheel 11 to stop the film winding. The distance by which the film moves thus depends on the distance by which projection 3 moves, and the initial position of projection 3 depends on the setting of pin H when the masking blind is adjusted. The gearing is such that the film is stopped after a movement equal to the length of film exposed. A modification is described in which the parts take different forms and are differently arranged, but act in a generally similar manner. A stand for the camera A, Fig. 10, comprises two parallel motion linkages 101, 102 and 103, 104, pivotally supported at 108 on a clamp 118 fixed to a table or plate 117, and supporting a bracket 107 pivoted at 109, 110 and carrying the camera. The camera can thus be moved in any direction, but with its optical axis at a constant angle to the copy-supporting surface 117. A. bar 119 fixed to bracket 107 serves to determine the distance of the camera from the copy and to indicate the fixed end of the field to be recorded. A tube 121 contains a wire illuminated by a lamp 120 and lenses 123, 124 which project the image of the wire on to surface 117, and pivots about an axis passing through the optical centre of the camera lens. The tube is connected by a link 130 to a rack 129 engaging a pinion 128 fast with the setting member of the blind, so that the image of the wire on surface 117 indicates the variable end of the field to be recorded. A lamp 111 for illuminating the copy is mounted on bracket 107, and is lit at the moment of exposure by a mercury switch operated by the exposure initiating means.