GB264046A - Improvements in or relating to means for effecting simultaneous reproduction of motion and sound - Google Patents

Abstract

264,046. Brown, S. April 20, 1926. Differential speed indicators.-Relates to indicating-devices by means of which synchronous working of a kinematograph and a sound-reproducing machine may be effected, and particularly to apparatus of the kind described in Specification 27717/08, [Class 40, Electric telegraphs &c.]. The indicator, Fig. 2, comprises, a hand I<1> moved step-by-step by an electrical escapement, to which current impulses are transmitted by means of a make-and-break contact device D, E, operated by the spindle B of the sound-reproducing machine R, Fig. 1. The hand moves over an indicating member I which is rctated by gearing driven by the kinematograph projector C, the gearing comprising a worm M on a spindle L, which is connected by sprockets and a chain F to the mechanism of the projector. According to this invention, the worm M is splined on the spindle L, along which it may be moved to some extent in either direction by means of a fork U carrying a rack V engaging with a pinion X, the pinion being mounted on a spindle Y bearing a knob and an indicating pointer (not shown). The purpose of such movements is to correct for accidental variations in phase between the two machines, due, for example, to the reproducing needle being jarred from its proper position on the track. A scale over which the pointer on the spindle Y moves is calibrated to indicate phase differences, e.g. in terms of revolutions of the record. To correct for a known difference in phase, the pointer on the spindle Y is turned in either direction through the proper angle, thus altering temporarily the relative positions of the hand I<1> and its dial. The speed of the kinematograph is then changed until the necessary correction, indicated by the return of the hand I<1> to zero, has been brought about.