| 摘要 |
1,236,375. Film advancing mechanism. EASTMAN KODAK CO. July 18, 1968 [July 19, 1967], No.33249/67. Headings G2A and G2E. Film advancing mechanism, especially for joined lengths of film having unperforated portions at the joint, comprises a carriage 3 which reciprocates along a channel 2 and carries feed claws 14 pivoted in blocks 11 and extending through slots 12 to engage the film; the stroke of the carriage 3 equalling or exceeding the perforation pitch, but being less than twice the pitch and the claws 14 being spaced from each other a multiple of the pitch, so that although one claw may abut an unperforated portion of film, the other will engage a perforation. The claws 14, biased by springs or gravity against the film, are cammed so that they trail over the film on the return stroke, a pawl 6 preventing film return. The carriage 3 may be stopped if film tension becomes excessive e.g. it may be reciprocated by a piston-driven bar magnet (17) Fig.5 (not shown) which abuts a magnet (18) fixed to the carriage 3, the attractive force between the magnets being less than the film breaking force. The mechanism is intended for use in a photographic printer or a film projector. |
