Patent GB-359162-A (GB)
Title: Improvements in synchronising systems and apparatus more particularly applicable for synchronising kinematographs with sound recording or reproducing apparatus
IPC: G03B31/00
Filed: 1930-09-25
Abstract: 359,162. Associated working of sound recording or reproducing apparatus and kinematographs. THRELKELD, T. G., Jesmond, Colborne Way, Worcester Park, Surrey, and HOUGH, T., 62, Glengall Road, Peckham, London. Sept. 25, 1930, No. 28777. [Class 40 (ii).] Comprises an apparatus for synchronizing the running of two machines, more particularly for maintaining synchronism between a kinematograph projector or camera and a sound reproducing or recording machine, which latter is driven at a constant velocity by separate driving means. A gramophone 1 drives a rotary electric impulse transmitter 6 comprising a circular disc 8 provided with a series of peripheral contacts 9 which are electrically connected through the turntable spindle 2 with a conducting disc 10. The kinematograph 4 is driven by an electric motor 5 and drives a receiver 7 comprising two axially aligned discs 11, 12 provided with a series of contacts 13, 14, respectively. The drive to the discs 11, 12 is transmitted through a ratchet wheel 17 on the spindle 15 and a pawl 18 carried by the discs. The contacts on each of the discs 12, 13 are in staggered relationship relatively to those on the other. Brushes 19, 191 bear on the discs 8, 10 respectively, and brushes 20, 20<1> respectively contact with the discs 11, 12. The brush 191 is connected to a battery 22 and thence to the joined ends of two relay coils 24, 25. The brush 19 is connected to a terminal 28 on the casing 16 of the receiver 7 to establish electrical connection with the contacts 13, 14. The brushes 20, 20<1> of the receiver are connected to the ends of the relay coils 24, 25, respectively. The relays are associated with spring-controlled contact blades 31, 32. In use, the apparatus is adjusted by means of the ratchet and pawl 17, 18, so that while the machines are running in synchronism the circuit of the battery 22 is maintained open. Should the kinematograph speed increase relatively to that of the gramophone, the contacts 13 of the receiver disc 11 are brought successively into contact with the brush 20 at the same time as the contacts 9 are brought into contact with the associated brush 19 thus closing the battery circuit at each engagement of the contacts with the associated brushes, so intermittently energizing the relay coil 25. The contact blade 32 is thus operated to close the contacts 321, 35 so that the current supply to the motor 5 is caused to flow through the whole of a resistance 38 and the speed of the motor 5 is reduced until the machines are again running in synchronism. Should a relative reduction in the kinematograph speed take place, the contacts 14 on the disc 12 engage with the brush 20<1> at the same time as the contacts 9 on the disc 6 are brought into contact with the brush 19 thus intermittently energizing the relay coil 24 and operating the contact blade 31 to short circuit the resistance 38 and speed up the motor 5. One of the contacts on the transmitter disc 6 is elongated, as at 9<11>, to make contact with a brush 44 at each revolution of the disc, while an insulated contact 45 on the receiver 7 makes contact with a pair of associated brushes 46, 47 at each revolution of the receiver. The brushes 46, 47 are connected in the circuit of a lamp 49 while the brush 44 is connected in the circuit of a lamp 51. These auxiliary contacts are so situated that the circuits for both lamps are closed together at each revolution of the discs 6, 7 when the machines are running in synchronism. Thus simultaneous lighting of the lamps 49, 51 affords an indication that the transmitter and receiver discs are set in correct relation at starting, and simultaneous flashing of the lamps thereafter indicates that the machines are running in synchronism. The speed of the kinematograph motor may be manually adjusted if necessary by selective depression of one of the spring plungers 52 connected with the contact blades 31, 32.