GB405730A - An improved device for forwardly feeding roll films in roll film cameras - Google Patents

Abstract

405,730. Photographic roll - film cameras. THORSCH, B. B., 30, Bõrensteiner Strasse, Dresden, Germany. Sept. 5, 1932, No. 24753. Convention date, Sept. 5, 1931. [Class 98 (i).] Relates to feeding devices for roll-film cameras of the kind in which the winding-spool is actuated by means of a rocking lever 2, the stroke of which is progressively diminished by means of a cam plate. According to the invention, the pawl 20 for effecting the advance of the cam plate 12, is actuated by means of a pin, protrusion, cam, or the like 23, capable of rotating together with the lever 2. In the form shown, the pin 23 is secured to a disc 5 mounted on the same shaft 3 as the operating handle, and engages with a spring-controlled pivoted lever 18 on which the pawl 20 is mounted. The pawl engages with the teeth of a wheel 10 secured to the shaft 11 of the cam plate 12 and effects a slight rotation of the cam plate on each downward stroke of the lever 2. The length of this downward stroke is determined by the position of the cam, which forms an abutment for a spring-controlled member 13 pivoted at 15 to the lever 2 and having a pin-and-slot connection 16, 17, with the casing 1 of the camera. A spring-controlled pivoted catch 24 prevents unintentional backward rotation of the cam plate. A wheel 8 on the film-winding shaft 9 meshes with a wheel 7 loosely mounted on the shaft 3. A number of pawls 6 are mounted on the wheel 7 and engage with the teeth of a ratchet wheel 4 which is rigidly secured to the shaft 3. This arrangement provides that the shaft 9 of the winding spool is rotated in one direction only.