Patent GB-637855-A (GB)
Title: Improvements in photographic projection copying apparatus
IPC: G03B27/465
Filed: 1946-08-01
Abstract: 637,855. Photographic copying apparatus. WILLIAMSON, C. M. Aug. 1, 1946, No. 22979. [Class 98 (i)] In apparatus of the type in which a camera is guided to move in a predetermined. path towards and away from a copy holder, more particularly to be used for making microfilm copies of documents on 35 m.m. film, the camera is provided with an illuminated graticule and a projecting lens or graticule objective to project on to the copy holder an image of the graticule which defines for every position of the camera, the boundaries of the area of the copy holder which will be copied on the film. This provision enables copy matters of varying sizes to be correctly located so that they are copied with the minimum reduction ratio within the limits of the size of film in use. The graticule objective and the camera objective may be placed side by side and provided with a single pivoted blade to serve as shutter for either of them in turn, and the graticule beam is arranged to incline, according to the camera distance, so as to maintain coincidence between the graticule image and the camera field, focusing for both objectives being automatic. Fig. 1 shows the camera casing 1 with film magazine 2 supported on bracket 3 which is slidably mounted on vertical column 6 above a table top 7 serving as copy holder. Lamps 13 on standards 12 illuminate the copy for exposure purposes. The camera casing 1 contains a lamp 14, Fig. 3, which may shine through an opening 23 in a box 22 towards a condenser in horizontal housing 24 carrying the graticule 30 which has " tennis court " marking corresponding to a fully opened camera objective and also one masked to expose a smaller area of film, and the beam from the graticule is diverted by a reflector 36 set at approximately 45 degrees to pass through graticule objective 34 to the copy holder 7. On movement of the camera up or down the column 6, two rocker bars 52 secured by a strip hinge 53 on a partition 21 of the camera casing 1 are rocked in a vertical plane by cam 55 anchored to one end of a telescopic rod 56, the other end of which is attached to the column 6, to cause a stirrup 50 carrying an objective slide 31 to impart a movement to the objectives 34, 35 to maintain focus, while. a plate cam 63 also carried by the stirrup 50 moves a lug 62 on the mount of the reflector 36 to cause the latter to move about its pivot 60 to incline the graticule beam and so maintain the graticule image on the copy holder 7 in central position relative to the camera objective 35. A counterweight and chain (not shown) in the column 6 enable the camera to be raised or lowered by a motor 11 operated by reverse and off switch CS. A negative film in the container 2 is driven by a motor in camera casing 1, and connections, from mains switch MS, are provided so that an operator may place a document on copy holder 7, adjust camera height by switch CS so that the graticule image coincides with the area he wishes to copy, at which time the lamps 13 burn dimly, operate a foot switch (not shown) to illuminate the lamps 13 at full voltage and displace the shutter 40 to cover the graticule objective 34 instead of camera objective 35 and so effect exposure, and then to move the film, restore the shutter to its original position as shown and decrease illumination of the lamps 13, to leave the apparatus ready for the next sequence of these operations. Specifications 596,185 and 605,563 are referred to.