Patent GB-694571-A (GB)
Title: Improvements in or relating to a photographic roll-film camera
IPC: G03B19/04
Filed: 1950-05-19
Abstract: 694,571. Photographic roll-film cameras. ACKERMANN, A. May 19, 1950, No. 12655/50. Class 98 (i). The camera comprises a camera body adapted to accommodate removable roll-film carriers sealed against the entry of light on removal from the camera body, one being, e.g. a carrier for a colour film and the other for a black and white film, wherein the camera body carries an exposure button and film-winding means adapted to be brought into operative engagement with a take-up spindle in the roll-film carrier and wherein insertion of the roll-film carrier produces engagement of an element in the roll-film carrier driven by the film with a locking device in the camera body which prevents winding of the film, the locking device being released by operation of the exposure button, which is thereafter locked until the film winder has been operated to bring a new section of film into the exposure position. As shown in Figs. 7, 8, the camera body 2 has a rectangular recess open at the back to receive the film carrier 1. The carrier has an aperture in front which is closed, when removed from the camera body, by a pivoted flap 20 which is held closed by a pin 22 on a disc 21 on a spring-urged shaft 29. When the carrier is in serted, a bracket 27 on the body engages a lever 75 on shaft 29 and so moves the pin 22 away from flap 20 which is then raised by a pinion 25 fast therewith engaging a rack 26 on the body. The film 81 is fed from a supply spool 9 over guides to a take-up spool 3 which is engageable with a film winding knob 8 mounted to slide axially in the body. The film perforations engage a sprocket 10 fast with a disc 14. Whenever a new length of film is fed, disc 14 rotates once and a pin 73 thereon moves a toothed wheel 12 fast with a counter disc 11. The film also engages sprockets 5 (see also Fig. 9) fast with a gearwheel 6 at the top of the carrier which, when the carrier is placed within the body, meshes with a gear-wheel 7. The shaft 35 of wheel 7 carries a cam 33 and a disc 32. A disc 31 loosely mounted on shaft 35 is connected to disc 32 by pin-and-slot connections 82, 83 (Fig. 10), and leaf-springs 44. The discs 31, 32 have slots 101, 102 which, when in alignment, are engaged by a spring-urged pivoted catch 43. When the shutter release 50 is depressed, the sloping surface of a latch 38 engages a slidebar 30 and moves it against action of a return spring so that a projection 41 thereof rocks catch 43 to remove it from slots 101, 102. Springs 44 then rotate disc 31 relatively to disc 32, so that catch 43 cannot re-engage the slots when bar 30 moves back, passing over latch 38 so that the release 50 cannot return. In this position a pin 51 on release 50 enters a hole 52 in the film carrier so that it cannot be removed from the camera body. The film is now wound, turning gear-wheels 6, 7 and shaft 35. A retarding member 53 bears on disc 31 with a pressure insufficient to prevent action of springs 44 but enough to cause disc 31 to turn more slowly than disc 32, so that slots 101, 102 come into alignment, and after one revolution are again engaged by catch 43, stopping the film wind. At the same time, cam 33 acts on a pin 34 on bar 30 which is thereby slid back, releasing latch 38 so that another exposure may be made.