GB365057A - Device for automatically adjusting the size of the loop in kinematographic apparatus - Google Patents

Abstract

365,057. Kinematograph apparatus. OEHMICHEN, E., Rue de Graviers, Valentigney, Doubs, France. Oct. 8, 1930, No. 30110. Convention date, Jan. 27. [Class 97 (i).] In kinematograph apparatus having intermittent feed mechanism, the feed and take-up rollers are in the form of friction drums adapted to engage the edges only of the film, and the size of the loops is automatically regulated by utilizing the natural spring of the film strip to vary the pressure on the friction roller or the arc of contact therewith or both. In one form as applied to the feed side of the apparatus 5, Fig. 3, the friction drum 2 is driven at a speed in excess of the average speed of the film, and coacts with a roller 4 to enclose the loop 3. As the loop shortens or lengthens the variation in the pressure on the driving drum or the arc of contact serves to readjust the loop to normal proportions. In the case of the take-up roller, the speed of the roller is less than or in the reverse direction to the speed of the film. Another form of construction comprises a lever 21, pivoted at 22 and biased by a spring, gravity, &c. The film is looped between a roller 14 and a roller 16 on the end of the lever and passes between another roller 17 and the friction drum 18. The movement of the lever may be used to actuate electric, hydraulic, &c. relays for varying the pressure of the film on the drum. Safety rollers 25 carried by resilient arms 26 may be mounted in the loops. The driving drum construction may be of the kind described in Specifications 296,728 and 305,776, [both in Class 97 (i), Optical systems &c.].