Patent GB-236649-A (GB)
Title: Improvements in the art of producing motion pictures and sound synchronising therewith
IPC: G03B31/04
Filed: 1924-04-09
Abstract: 236,649. Imray, O. Y., (Aleograph Co.). April 9,1924. Combined working of phonographs with kinemaiographs; driving; feed-motions; mandrels; cylinder records.-Relates to combined kinematographic and phonographic apparatus in which counters are provided in association with the machines, to enable them to be set in synchronism. The phonograph and the kinematograph are directly geared together, and a clutch is provided which allows the machines to be positively connected in any one of a predetermined number of settings with respect to each other, which number corresponds to the number of pictures in a given length of film. In the apparatus shown, the kinematograph drives the phonograph through a shaft 50, one end of the shaft having a worm or spiral gear 51 meshing with a gear 52 on the main shaft 7 of the projecting-machine, and the other end bearing a worm or spiral gear 49 driving a wheel 48 which is fixed to a clutch member 47 loose on the mandrel shaft 27 of the phonograph. The other member 43 of the clutch is splined on the shaft 27, and is movable by means of a yoke 44 into or out of engagement with the part 47. The kinematograph film is numbered, preferably along one edge, in units of length (each one of which corresponds to one revolution of the phonograph mandrel), and each unit is also provided with a series of numbers, one for each picture in it. The mandrel has a circumferential index 54, Fig. 1, the divisions of which correspond with the number of pictures in a unit length of film ; the number of teeth in each of the clutch-members 43, 47 is the same as that of the divisions of the index 54. A reversible counter 53 is operatively connected to the shaft 27, to indicate the number of complete revolutions thereof. The feed-mecha.nism of the sound-box 34 comprises a screw 29, connected to the mandrel shalt 27 by spur gearing (not shown), and carrying a nut formed on the sound-box carriage 33, which is guided by rails. A crank 40 and gear-wheels 41, 42 are provided so that the screw may be rotated by hand to return the sound-box to the starting-point after a record has been played through, or to set the sound-box in any desired position. Means are provided for ensuring that the record can be placed on the mandrel only in one definite position. For this purpose, the mandrel and a metal lining on the record may both be tapered, the lining having a notch to engage with a key fixed at one end of the mandrel. There must be agreement, at the commencement of the operation of the two machines, between the film and sound record indications provided respectively by the numbers on the film and the counters 53, 54. If, them, synchronism should be interrupted by the breaking of the film, it can be restored after the film has been repaired by declutching the driving connection between the record mandrel and the kinematograph and revolving the mandrel independently until the number indications are again in agreement. In making the sound record, the camera and the sound-recording machine are geared together, and an electromagnetic sound-box is used, in circuit with one or more transmitters located in proximity to the actors. The sound-reproducer 34 is a microphonic sound-box, connected as shown diagrammatically in Fig. 12 in circuit with a battery 72 and the primary coil P of a transformer. The secondary transformer-coil S is connected to the diaphragm-operating coil 74 of a loud speaker 68 (which as shown is of the moving coil type), arranged behind or adjacent to the picture screen 100. A rheostat 75 is connected in shunt with the coil S, to control the volume of sound emitted. The field magnet 70 of the loud speaker is connected directly to the battery 72 and to one pole 80 of a switch 76, the other pole 82 of which is joined to the primary P of the transformer. An indicator lamp 77, connected as shown, lights up when the switch 76 is closed, and thus shows when the apparatus is set for operation. In order that the sound-reproducing circuit may be broken automatically if the film breaks, a switch comprising two normally-contacting spring fingers 88, 89 is arranged in the battery circuit as shown. A spring-controlled insulating arm (not shown) is normally held inoperative by the film, but if a 'breakage occurs, this arm is released and passes between the fingers 88, 89, thus interrupting the circuit.