Patent GB-573584-A (GB)
Title: Improvements in or relating to photographic copying apparatus
IPC: G03B27/465
Filed: 1943-12-01
Abstract: 573,584. Photographic copying and projection apparatus. EVANS, C. V. Dec. 1, 1943, No. 20068. [Class 98 (i)] Copying apparatus of the kind comprising a roll-film camera using small-size film, with its lens, shutter, and focusing-mechanism mounted on a stand to which the roll-film back of the camera is fitted, and having means for operating the shutter and feeding the film stepwise at each exposure, is combined with a projector unit adapted for fitting to the camera back so that a film bearing images copied in the camera may be fed stepwise through the camera by the filmfeeding mechanism thereof, and projected for viewing upon a screen. Provision is also made for displacing the roll-film back to replace it in the focal aperture by a focusing screen carried by the back ; for masking the focal aperture and the screen aperture simultaneously to the same extent ; for adjusting automatically the length of film fed and an exposure-counting mechanism in accordance with the extent of masking ; and for automatically focusing the lens for different scales of enlargement. As shown, the camera bellows 17, Fig. 1, is supported beneath an aperture in a carriage 16 adjustable vertically on a pillar 10, the shutter casing 19 and lens 18 being supported by a slide which is displaceable vertically, on a track 21 depending from the carriage 16, by a belt-crank lever 22 pivoted to the carriage and having a roller 24 bearing against a cam on the pillar, so that as the carriage is moved up and down the pillar, the lens is automatically focused upon a baseboard 11 supporting the document to be copied. The roll-film back 26, fitted with a detachable side-plate for film loading, has a centrally-disposed front plate 28 slidable on rails 27 on the carriage 16, and has an extension 53 fitted with a focusing-screen 29, Fig. 7, which may be substituted for the film in the focal aperture of the camera by sliding the back into the position shown in broken lines. Any focusing correction required is made by adjusting the lens axially in the shutter casing. A cover slide 59, Fig. 7, actuated by a knob 62 is provided to obscure either the film aperture or the focusing- screen aperture. The back has film chambers on each side of the plate 28, between which the film is fed stepwise by air-pressure supplied as by a foot-pump to a cylinder 74,'the piston 75 of which is linked to a crank arm 76 carrying a pawl 77 engaging a ratchet wheel 78 coupled by spur gears to a film-feed sprocket on a shaft 81, which also drives a belt transmitting the drive to the film take-up spindle 69. The film is held upon the feed sprocket by a pair of rollers mounted on a spring arm. A foot-pump may also actuate the shutter setting and release mechanism. The focal aperture may be reduced to half width by a pair of masking leaves pivoted one on each side on spindles 64 coupled together by crank arms 65 and a link 66 for simultaneous spring-biassed movement initiated by a handle on the spindle of one of the crank arms ; and a link 85 connects one of said arms to a pivoted stop 84 which is turned, when the masking leaves are moved into operative position, so as to limit the throw of the crank 76 and therefore also the feed movement of the film. The crank 76 also actuates, through links 86 ... 89, the spindle 73 of an exposure-counting device, which consequentially registers at only half rate when the masking leaves are operative. The spindles 64 carry also a similar pair of leaves for simultaneously masking the focusing screen 29. The roll-film back has behind the focal window a removable casing 44, Fig. 7, housing a spring-biassed, hinged film pressure plate 38 movable into and out of operative position by rotating an external knob 47. When a film which has been copied in the camera and processed is to be projected in the apparatus for inspection, the casing 44 is replaced by a projector head, comprising lamp 93, Fig. 8, reflector casing 30, and condensers 95, whereby, with the camera shutter set open, an image on the film is projected on to a screen placed on the base board 11. A horizontal disposition of the apparatus is also envisaged.