GB324005A - Improved means for synchronising cinematographs and sound reproducing apparatus - Google Patents

Abstract

324,005. Hepworth, C. M. Sept. 14, 1928. Combined working of kinematographs with gramophones .-A synchronizing device for combined kinematograph and sound-reproducing machines wherein synchronism is obtained without disturbing the operation of the latter element of the machine, comprises shafts 5, 18 rotatable in unison with the sound-reproducing device and projector respectively, a rheostat in the energizing circuit of the projector motor, and a controller for the rheostat consisting of a brush 10 on one of the shafts wiping a co-operating con tact element 11 on the other shaft. The soundreproducing device and the projector are driven by separate motors. The rheostat is in the form of a series of resistances 13, which are mounted on a cylinder 12 on the shaft 18 and are connected to a ring of segments constituting the contact element 11. The current enters the rheostat by way of a brush 15 and slip-ring 14 and leaves it by a brush 17 and slip-ring 16. The brush 10 is mounted on a, disc 9 on the shaft 5. Should a difference of speed occur between the gramophone and projector motor, the brush 10 will move over the segments according to the direction of the difference and resistance will be added in, or cut out of, the energizing circuit of the projector motor until the speeds are equalized. The resistances may be on a stationary part of the apparatus and the current led to the resistances by way of a series of slip-rings on the shaft 18. Specifications 7694/13, [Class 88 (i), Musical instruments, Automatic], 325,882 and 331,256 are referred to.