GB457353A - Improvements in means for controlling the film motion in sound recording or reproducing apparatus - Google Patents

Abstract

457,353. Sound-film feeding devices. HEPWORTH, R. PLATT-, 68, Paddington Street, near Sydney, Australia. Aug. 20, 1935, No. 23395. Convention date, Aug. 22, 1934. [Class 40 (ii)] Means for controlling film motion in sound, or combined motion picture and sound, recording or reproducing machines comprises a sprocket and a friction drum or cylinder located on opposite sides of the sound gate and mechanism to drive them at different peripheral speeds for drawing the film under tension past the sound gate, the construction being such as to permit slip between the drum or cylinder and the film so as to maintain the speed of the film past the gate substantially constant. As shown the film 11 is held in frictional contact with a drum 13 by a spring influenced impedance slide or pad 15 which bears on the marginal portions only of the film so as to remove flutter transmitted from the intermittent gear. The film then passes over a small arc of the curved face of the sound gate 16 to a sprocket 18 with which it is retained in mesh by a jockey 20. From thence the film passes with a looped span 21 to the take-off sprocket 22. The drum 13 is fixed to spindle 14 and thence connected by gears 23, 24, 25 and spindle 19 to sprocket 18 with which it rotates in unison, the diameter'of the drum being less than the face diameter of the sprocket. According to a modification, Fig. 2 (not shown), the drum is made larger in diameter than the face diameter of the sprocket and is placed on the shaft 19, the sprocket being placed on the shaft 14. A jockey pulley positioned within the bifurcation of the impedance shoe, is provided to increase the friction of the film on the drum. The Specification as open to inspection under Sect. 91 comprises also an arrangement in which the drum is replaced by a frictionally driven sprocket. This subject-matter does not appear in the Specification as accepted.