Improvements in or relating to synchronizing arrangements for sound cinematography

摘要

878,956. Automatic speed control systems. TRAINQUART, R. June 12, 1959, No. 20276/59. Class 38 (4). A gear-wheel 33, forming part of a differential gear, is driven in accordance with the speed of a magnetic tape for sound recording, whilst the speed of a gear-wheel 36 depends upon the linear rate of advance of a cinematographic film. When the ratio between the speeds deviates from a predetermined value, a planet cage 39 is displaced and a slider 40 is adjusted in relation to a resistor 42 in circuit with the electric motor driving the film in such a manner that synchronism is restored. The gear-wheel 33 is coupled to a pulley 27 engaging the magnetic tape, the gear-wheel 36 being secured to a disc 34 having magnetic core members 35 which cooperate with solenoids 43. A step-by-step rotation is imparted to the gear-wheel 36 by means of the solenoids which are energized in sequence at a frequency which depends upon the rate of feed of the film.