Patent GB-253142-A (GB)
Title: Improvements in film photographic cameras
IPC: G03B1/48
Filed: 1926-06-07
Abstract: 253,142. Nistri, U. June 5, 1925, [Convention date]. Aeronatuical cameras; roll-film dark slides. - The camera is continuously driven and comprises (1) a movable plate which presses the film forwards against the edges of the focal aperture during exposure, and is retracted during the feed movement of the film; (2) a roller-blind shutter carrying, adjacent to the exposure aperture, resiliently mounted rollers which press the film during exposure against the aforementioned pressure-plate; (3) an intermittently-driven film feeding- roller carrying on its ends diametrically-disposed pins which penetrate in succession the margins of the film and cause it to move with the roller; (4) an adjustable friction clutch for transmitting the movement of the feeding- roller to the take-up spool of the film; (5) a holder for the film reels, pivotally mounted in and removable from the camera casing; (6) a take-up spool having a metal tongue slotted to engage the end of the film; and (7) driving- mechanism, operated from a continuously-rotating shaft, for actuating the pressure plate, the shutter, and the film feeding-roller. In the form shown, the film 5, Fig. 1, which is adapted to receive a picture larger than a kinematograph picture, is contained in a removable casing 1 pivoted in the semi-cylindrical rear casing H of the camera, and is wound from the reel 2, over an idle roller 3, by way of the focal aperture A, B, to the feeding roller 4, and thence to the take-up spool 6, which carries a slotted metal tongue 21, Fig. 4, to which the end of the film is secured. Upon a continuously-driven shaft 22 is mounted a cam 9 which actuates link mechanism 10, 11 associated with a spring-urged plate 8, so that this plate presses the film forwards against the edges of the focal aperture during exposure, but is retracted to disengage the film during the feeding movement. The film feeding mechanism comprises a wheel 23, Fig. 5, fast with the shaft 22, driving a wheel 24 which is loose on the shaft 25 of the roller 4 and carries a pawl 27 adapted to engage a double-toothed cam 26 fast with the shaft 25. Once in each revolution of the wheel 23 a pin 28 thereon is adapted to release the pawl 27 from the cam 26, so that the cam, and therefore also the feeding roller 4, is driven during only half a turn of the wheel 24, and remains stationary during the other half. The roller 4 carries on its end faces a pair of reciprocating pins, Fig. 9, which are displaced to perforate the film, and cause it to move with the roller, by a stationary cam 53 engaging rollers 51, 52 on the pins. Fast with the cam 26 is a ratchet wheel 33, Fig. 5, cooperating with teeth 32 mounted on a wheel 31 which is loose on the roller shaft 25 and drives the take-up spool through friction-clutch gearing adapted to compensate for the varying diameter of the spool. This gearing may be manually disengaged when it is necessary to re-load the camera. Shutters, roller-blind.-The shutter comprises a blind adapted to be set by winding from a spring roller 50 on to a roller 45 which is driven from the main shaft 22 through toothed gearing including a cam gear and trip similar to that shown in Fig. 9, so that after the blind has been wound it is suddenly released to make the exposure, and is thereafter rewound. Upon the blind is mounted a member provided with an exposure aperture 18 and also carrying, on each side of this aperture, rollers 15 which are spring-urged so that they press the film upon the plate 8 as the aperture 18 traverses the focal aperture.