GB383060A - Improvements relating to driving sound films in sound recording and reproducing apparatus - Google Patents

Abstract

383,060. Sound recording and reproducing apparatus. BRITISH THOMSON-HOUSTON CO., Ltd., Crown House, Aldwych, London.-(Assignees of Kellogg, E. W. ; 17, South Colonial Avenue, Moorestown, New Jersey, U.S.A.) Nov. 12, 1931, No. 31378. Convention date, Nov. 12, 1930. Addition to 316,320, [Class 40 (ii), Phonographs &c.]. [Class 40 (ii).] The film-feeding apparatus described in the parent Specification is arranged and driven so that the flywheel and drum maintain a slight tension on the film passing to the drum from a feed sprocket, this tension tending to reduce the speed of the drum. The film and feed rolls are housed in a flanged casing 1 supporting a sleeve bearing 11 for the shaft 10 of the drum 8, on which sleeve is mounted a boss 12 carrying a wheel 13 and an electromagnet 16 with windings 15. An armature 20 carried by a flywheel 21 fixed to the shaft 10 extends into the gap between the poles of the magnet. The boss 12, and thereby the magnet, is driven, as by a synchronous motor, through gears 23, 24, 13 at a speed about 15 per cent in excess of the speed to be transmitted to the drum through the pull on the armature 20, resulting in a small tension in the film between the drum and the sprocket 7, which is driven by gear 9 from the gear 13. The film is held in contact with the sprocket by guide rolls 27, 28 on arms supported in eccentric bearings with operating knobs 29 to separate the rolls for threading the film, and is led round a flanged guide roll 31 to the drum 8 from which it passes over a guide roll 34 to the sprocket 7. A guide roll 30 on an eccentrically mounted arm 36 holds the film against the roll 31.