Patent GB-441920-A (GB)
Title: Improvements in photographic roll film cameras
IPC: G03B19/04
Filed: 1934-04-26
Abstract: 441,920. Photographic cameras. REASON, R. E., CLIFFORD, T. W., and KAPELLA, LTD., 104, Stoughton Street, Leicester. April 26, 1934, No. 12543. [Class 98 (i)] In roll-film cameras of the kind in which the successive exposure positions of the film are determined by winding of measured lengths, a counting device is provided with a cam which controls a detent lever coacting with the film-winding mechanism, so as to ensure that the film can be wound to its first exposure only in the starting position of the counter. In that position of the counter, the film is wound continuously to the first exposure and then automatically stopped. Thereafter the counter is moved automatically step-bystep after each exposure, and after the last exposure, the cam again comes into play to permit continuous winding off of the tailstrip. A cover-plate is retained by a latch which is locked by the counter in all positions except the starting position. Figs. 10 and 11 of the drawings show the camera in side and front views. The take-up spool has three stops 4, 5, 6 spaced at 120‹ apart which are adapted to engage with a spring- pressed lever S for measuring of the exposure lengths of film. The hub 27 of the take-up spool has three laterally projecting lugs 38, 39, 40 which, at each winding movement actuate a spring-controlled lever L, which at its upper end acts as a spring pawl to drive the counter disc 43. The counter-disc has an annular rib 64 which, during the exposure of the film, supports a lug 82 on a lever F which is mounted on the same spindle 71 as the lever L and is connected thereto by a spring 80 biassing it in a clockwise direction. A lever P which is spring-pressed in a counterclockwise direction is tripped at each exposure to actuate the shutter. At each exposure the projecting part 60. of the lever P lifts the lever F and releases the detent lever S which swings in a clockwise direction to clear a stop 5 on the take-up spool. The winding of the spool first turns the lever L and with it the counter, then by means of an extension 75 resets the shutter lever, and by means of the extension 77 resets the detent lever so that its upper end lies behind the end 85 of the lever F. To allow continuous winding of the film to its first exposure position, the annulus 64 has a gap 65, a spring latch 67 and a protuberance 66 on the leading side of the gap. A projection 68 on the face of the disc coacts therewith to control the lever F so as to hold the detent out of action. The action is that the protuberance 66 lifts the lever so that the lever S swings in a clockwise direction and leaves the winding mechanism free, and actuation thereof operates the lever L so as to turn the counter and simultaneously interengage projections 92, 79 on the levers S and L respectively so that these two levers are interlocked in their open position. The lug 82 on the lever F drops under its spring control through the gap 65, until a projection 87 on an extension of the lever bears against the film strip and the end of the lever S bears against the step 86 of the lever F. The parts are now held in this position and the leading strip is wound off until an aperture therein comes opposite the projection 87. The lever F drops further, allowing the lever S to swing further in the clockwise direction and engage the stop 96 of the lever F. This frees the lever L which thereupon swings counter clockwise, lifting the lug 82 of the lever F past the spring latch 67, and the further winding movement moves the counter on one division and sets the parts in the position shown for the first exposure. When all the exposures are made, the cam and gap in the ring 64 operate to allow continuous winding of the tailstrip and automatic stopping when the strip ends. The spring latch retaining the cover plate coacts with a notch in the counter-disc disposed so that it can only be operated when the counter-disc is in the starting position. The apparatus is particularly designed for use with 16 mm. film, and the spool is made of larger than usual size so as to maintain for the exposure movements a substantially constant angle not exceeding 360‹.