Patent GB-550324-A (GB)
Title: Improvements in photographic projection-copying apparatus
IPC: G03B27/32
Filed: 1941-06-27
Abstract: 550,324. Photographic copying-apparatus. DEHN, F. B. (Martin Co., G. L.). June 27, 1941, No. 8130. [Class 98 (i)] A photographic projection copying apparatus, of the type in which the subject to be copied is mounted on a panel movable by means of a carriage travelling on a track, includes electrically conducting rails which are mounted on the track and are engaged by shoes mounted on the carriage and connected to the motor by which the carriage is moved. In the apparatus shown, a carriage formed by a framework having side and cross bars 26, 28 is movable to and from the camera A on tracks carried by the ceiling or otherwise supported, wheels 38 mounted on the carriage running on lower flanges 10 of the tracks. Pneumatic wheels 46 carried by upwardly spring-pressed brackets mounted on the frame engage the underside of the tracks, and rollers 47 engage their inner edges. The carriage is moved along the rails by a reversible motor 78 which through gearing 76 and shafts 74 drives rubber-tyred wheels  which frictionally engage the undersides of the tracks. The carriage supports at its front end a vertical frame having upper and lower crossmembers 30, 32 between which is mounted a large flat panel 102 on which either, the copy or the sensitive material is held by suction. For this purpose a number of grooves in the face of the panel, indicated by heavy lines in Fig. 3, extend from apertures 106 passing through to the rear face of the panel; to which apertures are connected pipes leading to a pair of manifolds connected to two motor-operated suction devices 112. During exposure the copy is illuminated progressively by traversing across it a carriage having vertical walls 134 serving as reflectors for vertical lamps, such as mercury vapour tubes 136. The carriage is provided with wheels engaging the upper and lower edges of the cross-members 30, 32 respectively and it is traversed by a reversible motor (not shown) carried by it and rotating a wheel which engages the top cross member 30. A reversing switch 158 mounted on the carriage is operated by a push rod which at each end of the path of the carriage engages a stop adjustably secured to the cross-member 30, so reversing the movement of the carriage. The width of the copy exposed at any moment may be varied by adjusting two flexible curtains 148 mounted on spring rollers 150 on the carriage and operated by cables so arranged that the curtains move in opposite directions to vary the width of the exposure aperture formed between their edges. Four pairs of conductor rails 18, 20, 22, 24 are carried on the sides of the tracks on which the main carriage runs, with which engage contact shoes, four of which, 48, 50, 52, 54, mounted on spring pressed arms 64 pivoted on brackets 36 secured to the carriage, are shown in Fig. 7. One pair of the conductor rails serves to supply current at 440 volts for the motor driving the main carriage and for the transformers supplying the vapour lamps ; a second pair provides current at 110 volts for the motor which traverses the illuminting carriage, the air suction motors, and for " safe-light " and ordinary lamps for illuminating the panel 102 during manipulation; the other two pairs provide connections to switches 90, 186 by which the motors of the main carriage and of the illuminating carriage may be controlled from a point adjacent the cameras. A negative to be enlarged may be placed in the camera and illuminated by means carried by a carriage C, or the negative may be held in the carriage C.