Apparatus for moving the film in motion picture cameras or projectors

摘要

693,480. Kinematograph apparatus. VITARAMA CORPORATION. Feb. 18,. 1952, No. 4257/52. Class 97 (i). Intermittent film feed mechanism comprises a feed device to accumulate film ahead of the gate, an air chest having a port across which the film passes beyond the gate and means to supply air intermittently to the chest to exert pressure on the film to move it through the gate a movable retarder engaging the film to slow its movement during the latter part of each intermittent film movement. As shown, the film 10, fed to and from the gate. by a sprocket 13 with pressure rollers 15, 16, 38, passes under a spring- loaded roller 22 and over a rubber-covered roller 18 of the same diameter as the sprocket and driven at the same speed by gearing 28, 29, 30. The gate 32 has a pressure plate 33. Below the gate the film passes across the mouth of an air chest 35 with depending walls 75 adjacent the film edges. Air is admitted through the side wall of the chest by a port 72 in the rotating disc 60 which rotates once for each film frame fed. The film loop is thus enlarged on to curved flanges 37 projecting inwardly from the walls 75. Register pins 40 then enter the film perforations and the roller 18 moves the film until the perforation edges abut the pins while the film is tensioned by air admitted through a part 76. Flexible strips 36 across the mouth of the air chest prevent loss of air through the film perforations. The register pins are carried by a spring 44 and actuated by an arm 51 on a shaft rotated by a lever 55 carrying a cam follower 56 engaging the periphery of the disc 60 formed with a cam 70. The construction shown is part of a projector wherein light from a source 49 is reflected to the gate by the prism 50. In a larger projector separate upper and lower film sprockets are used with a direct light path.