Patent GB-165489-A (GB)
Title: Synchronisation of machines for recording and reproducing sounds and movements
IPC: G03B31/00
Filed: 1920-01-28
Abstract: 165,489. Verity, C. H. Jan. 28, 1920. Synchronism indicators.-Relates to apparatus for synchronizing a gramophone or the like with a kinematograph. According to the invention, revolution counters driven from the two machines are arranged within an operator's vision, and means are provided for varying the relative speed of the machines in accordance with the readings of the counters. Further, to ensure accuracy of synchronization, in conjunction with the counters two or more rows or series of electric lamps or other visual signals are provided, the lamps or signals being illuminated or operated successively by contact devices on the gramophone and kinematograph respectively. In the arrangement shown in Fig. 1, the gramophone is driven by an electromotor 11, and the kinematograph by a motor 10, the motors being started simultaneously when a switch 12<a> is closed. A counter 17 is driven by the motor 11, and a counter c<3> by the motor 10. Adjacent to the counter 17 is arranged a counter 16, the readings of which agree with those of the counter c<3>, the counter 16 being operated through a solenoid 15 by intermittent currents from a switch 13 which is driven by the motor 10. Each motor 10, 11 also operates a rotary contact-device comprising a fixed disc 21 having a circular series of contacts 22 and an annular contact 23, and an arm 20 which is rotated by the motor so as to connect each contact 22 in turn with the contact 23. In each case, the gearing between the motor and the counter and the rotating contact-arm respectively is such that one rotation of the arm corresponds to four unit indications of the counter. Two rows 24, 28 of lamps are wired as shown to the rotary contact-devices of the kinematograph and gramophone respectively. Thus the lamps in each series are successively illuminated, and by controlling the speed of the motor 10 (by means of a rheostat 35) the operator keeps the illumination of the lamps in the series 24 in step with that in the series 28, so as to obtain exact synchronism. The lamps are, as shown in Fig. 6 (which shows two pairs of rows of lamps, corresponding to two sets of apparatus to be synchronized), in separate compartments in a casing having a perforated cover 26 for each set. Coloured glass is used to distinguish the lamps of one series from those of another. The control of the motor 10 may be effected automatically instead of by hand, for example by operating the rheostat 35 by an electromagnet which is so arranged and so connected in the circuits of the lamps 24, 28 that it causes the resistance to be increased or diminished if the illumination in one set of lamps leads or lags with respect to that in the other. The kinematograph films and the gramophone records are provided with marks indicating the starting-points, and the film is also numbered, coloured, or otherwise marked at intervals to correspond with the counter-indications, so that in case of a break in the film the apparatus can be readily restored to synchronism. The speed of the electromotor driving the gramophone may be controlled by a resistance operated by a governor. For a continuous performance, two complete and independent installations, each comprising a gramophone, kinematograph, and synchronizing-apparatus as described, are preferably used. Specification 103,407, [Class 40 (ii), Phonographs &c.], is referred to. The first Provisional Specification describes the use of revolution-counters only, for indicating synchronism. The second Provisional Specification describes a modification of the counter that is electrically operated bv the kinematograph; it also describes a modified arrangement of the contact-devices operated by the machines to be synchronized, and of the lamps.