Patent GB-718917-A (GB)
Title: Improvements in photographic cameras wherein the film-winding mechanism is coupled to the shutter-setting mechanism
IPC: G03B17/42
Filed: 1952-04-10
Abstract: 718,917. Photographic cameras. DANZER, J. H. April 10, 1952 [April 16, 1951 No. 9178/52. Class 98(1) A photographic camera comprises a film winding-on spool and a film re-winding spool, a winding-on knob coupled to the winding-on spool and having a spiral track, a spring-loaded longitudinally slidable lever engaged with the track for radial movement relative to the knob as the latter is rotated, and a manual release shutter mechanism having a movable setting member engageable by the lever for setting the shutter as the knob is rotated, the knob having a radial channel at one end of its spiral track so that at the end of one turn of the knob the lever is caused to engage in the channel to lock the knob against further rotation, the setting member, in set position, serving to prevent return of the lever for dis-engagement from the channel until the shutter is released. The camera shown comprises a film winding knob 2 frictionally coupled at 22, 23 to a roll-film spool 24, the film, in travelling thereto from a supply spool normally freely rotatable relative to a knob 3, engaging a sprocket 15 carrying a cam disc 16 with two re-entrant parts 17. A spiral track 4 on the underside of knob 2 is engaged by a bent-up part 5 of a lever 6 so that rotation of the knob 2 for winding on the film moves this lever to the left in Fig. 2 against the action of a spring 7. Lever 6 has an arm 8 engaged between the forks 9a, 9b, of a member secured to the shutter whereby movement of the lever to the left winds up the shutter. Such movement of the lever 6 also releases a lever 12 pivoted at 13a whereby this lever 12 moves under the action of a spring 14 and a lug 18 engages the surface of the rotating cam 16, and a lug 11 engages a toothed exposure counting wheel 20 and rotates it through one tooth. Cam 16 continues to rotate until the lug 18 snaps into one of the re-entrant parts 17 thereof-this arrests the film movement, but by reason of the frictional coupling 22 the knob 2 can continue to rotate to wind up the shutter. When the shutter has been fully wound up the end 5 of lever 6 enters a radial channel 4a at one end of the spiral track 4 and is held there by the forks 9a, 9b until the shutter is released. Release of the shutter allows return movement of lever 6 under spring action and a nose 10 on the lever engages the lug 11 on lever 12 so that the latter is pivoted against the action of spring 14 and the cam disc 16 thereby freed. Lug 11 takes up a position in the light path of a view finder 21a, 21b, thus indicating that the film has not been wound on. In the re-winding knob 3 is threaded a bolt 27 carrying a plate 28 apertured at 29, this plate being held normally in the position shown by fingers 32 on a spring ring 31 which encircles a sleeve 25 carrying the spool which is normally freely rotatable. Sleeve 25 has a lug 34 which when the knob 3 is pulled out engages one of the apertures 29 in the plate and this locks the knob to the sleeve 25 and allows the film to be rewound onto the supply spool by turning the knob.