Patent GB-598202-A (GB)
Title: Improvements connected with photographic roll film cameras
IPC: G03B19/04
Filed: 1945-07-26
Abstract: 598,202. Photographic roll-film cameras. LOEBSTEIN, H.. and ENGELHARD, N. N. July 26, 1945, No. 19184. [Class 98 (i)] The camera is provided with a device operable by the film and adapted to control the camera opening, film winding and shutter setting and releasing mechanisms so as to prevent inappropriate operation of these mechanisms. As shown, the camera consists of a forward part 67, carrying the objective, shutter, and a lever system connected to the shutter setting and releasing members ; and a rear part 38 containing the spool holders, film winding mechanism, mechanism controlling the lever system carried in the forward part, and means for preventing unintentional opening of the camera whilst it contains unexposed film. The rear part 38 of the camera comprises a removable base member 40 on which the operating mechanisms are mounted closed off from the exposure frame 46, semi-cylindrical ends 39 which contain extentions 47 of the exposure frame housing the spools, a back plate hinged on the exposure frame and a fixed top cover having hinged portions above the spools for facilitating their removal. Starting with the camera ready for an exposure, as in Figs. 7 and 9, the sequence of operations is as follows : The sliding trigger 17 is pressed causing the pin 19 to rock the lever 20, Fig. 10, from its dotted line position to the full line position and release the shutter through lever 59 which is normally spring-urged into its dotted line position, and also to move the lever 28 from the dotted chain line position to its full line position so that a plate 29 on a vertically depending pivoting lever engaging lever 28 obstructs the shutter setting lever 30. Actuation of the trigger 17 also moves, by way of the cranked rod 53, the bar 15 to the left causing a projection 21 on the nose of the bar to engage with an upstanding flange on a cam 22, releasing the film winding mechanism by disengaging teeth 14 at the end of the bar from the ratchet wheel 12 on the take-up spool spindle. During the winding of the film it rotates a roller 23 bearing against it and hence drives, through gears 66, a disc 24 mounted eccentrically on the shaft of the cam 22 to reciprocate a lever 25, pivoted at 25<11>, which moves a spring pawl 25<1> so that the ratchet wheel 9 moves round one tooth, thereby rotating the coaxial disc 4 carrying the exposure numbers visible through a window. At the end of the film winding, the projection 21 rides off the cam 22 through the slot 57 and the teeth 14 relock the film wind, whilst the pin 19 returns to its original position and the lever 20 follows it so that plate 29 is moved out of the path of the shutter setting lever, allowing the shutter to be reset and completing the cycle of operations. Operation of the trigger 17 prior to setting the shutter is prevented by a projection 31 having moved into the path of the end of the lever 58, as shown in dotted lines, said projection only being movable out of its locking position by setting the shutter, whereupon the lever 28 assumes its dotted chain line position. The camera is maintained closed by sliding latches 44 held immovable by the periphery of the disc 4. After the last exposure has been made the bar 15 is held, as it returns during the film winding to its locking position, by a ridge 32 on the disc 4 engaging a projection 33 on the bar thus allowing the opaque end of the film to be wound off. The disc 4 is then positioned so that a keyhole is uncovered to permit insertion of a key controlling the latches or the word "open" " carried by the disc appears in a window, whereupon the noses 5 of the latches may be slid by means of thumbpieces into slots 6 arranged along a non- diametral chord of the disc to open the camera and allow the base-plate carrying the spools to be lifted out for reloading. To open the camera before the film is fully exposed, a projection 34 is turned which causes the pawl 37 to be reciprocated so as to push against successive teeth of the ratchet wheel 9, thereby rotating it and thus allowing the disc to be turned to the " open " position.