709,981. Photographic roll film cameras. HEIDECKE; R., [trading as FRANKE & HEIDECKE], June 2, 1950 [Feb. 23, 1949; Feb. 23, 1949], No. 13865/50. Class 98(1) In a roll film-camera having an exposure counter adapted to be operated against a return spring from a film-driven roller, the drive from the roller to the counter comprises gearing including an intermediate gear which is urged to an inoperative position by a spring and is moved against said spring into its operative position by closing the camera back. Preferably said gear is -carried by a pivoted lever which in the inoperative position of the gear releases a ratchet and pawl locking mechanism for the film wind. As shown, the winding knob 1 which is connected to the take-up spool (not shown) winds the film 2 in the direction of the arrow and thus by means of a film-driven roller 3 rotates a shaft 4 supported by a ball-andsocket mounting 5 and carrying a gear 6 meshing with a gear 7 on a lever 9 pivoted at 10 in the camera body so that a pinion 8 fast with the gear 7 only meshes with the toothed rim of an exposure counter disc 11 freely mounted on a fixed stub shaft 13 when the camera back 25 hinged to the body at 32 is closed, pivoting the lever 9 anticlockwise. A spring 14 between the stub shaft and the disc urges the disc clockwise so that the left hand end of a slot 17 therein is engaged by a pin 16 on a wheel 15 also freely mounted on the shaft 13 and connected to the disc by a spring 18. The wheel 15 is provided with a number of recesses spaced by a distance to a film feed of one frame and engaged by the tail 23 of a lever 21 which is pivoted in the body at 20 and has a nose 24 engaging a ratchet 22 on the film winding knob when the camera is closed, the lever 21 being held clear of the ratchet when the camera is open by the lever 9. In use the film leader strip is attached to the take-up spool and is wound on until a mark on it registers with a chosen mark in the camera, such as the tip of a slide 27 or the lever, the disc 11 being in its rest position with the numeral '0' appearing in a window 33 in the camera body. The camera back is then closed, pushing the slide 27 which is spring-urged against a projection 26 on it inwardly and so rocking the lever 9, to which it is pin-and-slot connected, anticlockwise a distance limited by an adjustable eccentric stop 12 to bring the gear 8 into mesh with the toothed counter disc 11 and to allow the tail of the lever 21 to bear against the wheel 15. The film is now wound on tensioning the spring 14 of the disc 11 until the numeral ' 1 ' appears in the window 33. and the wheel 15 is latched by the tail 23 of the lever 21 which in pivoting anticlockwise also engages the ratchet 22 and arrests the winding knob 1. To wind on a further frame, a knob 35 coaxial with the knob 1 is depressed against spring action so that a plate 37 engages a conical ,pin 38 on the lever 21 moving it clockwise to release the winding knob and the wheel 15. The film is then wound-on with the tail 23 riding on the periphery of the wheel 15 until a further notch allows the lever 21 to again effect latching. When the last frame has been wound on, a mark 39 appears in the window 33 and a mutilated portion 40 of the toothed disc 11 comes opposite the gear 8 so that by continued rotation of the knob 1 the trailer strip is wound up. In this position too, a disc secured to the wheel 15 presents a recess to a pin on a clockwise-urged lever pivoted in the body at and having a nose engaging in a loop on the camera back to hold it closed, so that the nose is withdrawn from the loop and the camera may be opened whereupon the tensioned spring 14 returns the counter disc 11 to its rest position shown. In this rest position, a second notch in the camera locking disc is presented to the latching lever so that the camera back may be closed when the leader strip has been wound off and the back is then latched on further film winding. In a modification, Fig. 2, (not shown), the slide 27 is connected to the.lever 9 by a hairpin spring.