GB499544A - Improvements relating to film feed mechanism for photographic roll film cameras - Google Patents

Abstract

499,544. Photographic roll-film cameras. FRANKE, P., and HEIDECKE, R. Feb. 16, 1938, No. 4852. Convention date, Feb. 20, 1937. [Class 98 (i)] In film feed mechanism which is automatically locked, on completion of each picture length, by a pawl which may be released by a cam by a reverse movement of the winding handle, the cam acts on the pawl through an intermediate lever which is only operative during the reverse rotation of the winding handle. In the form shown, the winding handle rotates a ratchet wheel 1 and a cam 3, and also, after winding the backing paper at the commencement of each spool, the notched wheel 7 (through gearing not shown). The pivoted member 8 has a projection. 8a to engage the notches on the wheel 7, and a tooth Sb to engage the ratchet wheel 1. It also carries a pivoted lever 12 which is held by a spring 12a against a projection 10 and itself has a projection 13. As the winding handle is rotated forward, the projection 13 is engaged in the enlarged end 5 of a groove 4 and is pulled down thereby so that the portion 6 of the cam 3 is not obstructed. When one of the notches in the wheel 7 moves under the projection 8a, the tooth 8b engages the ratchet wheel 1 to lock the winding mechanism. A reverse rotation of the handle however causes the projection 13 to ride up on the end 3a of the cam, and the notch 8a to be released from the wheel 7 to allow a further section of film to be wound.