GB519510A - Photographic system and apparatus for time and other announcements - Google Patents

Abstract

519,510. Optical sound-reproducing apparatus; clocks. SOLBERG, T. A. Nov. 24, 1938, No. 34200. [Class 40 (ii)] [Also in Group XVIII] A time-controlled announcing system comprises two concentric cylinders separately rotated by gearing with a clock, one of the cylinders carrying a photographic or like announcement record and the other operating mechanism which reciprocates a photo-electric device for scanning the record in timed relationship with the clock, the scanner being adapted to operate sound-reproducing means. In the apparatus shown, an electric clock drives through gearing 3, 13 two cylinders 7, 14 the cylinder 7 being fixed on a spindle 4 and 14 being mounted, concentrically therewith, on bearings 15, 16. The cylinder 14 carries a photographic or like transparent sound record. Between the cylinders extends an arm of a U- shaped frame 9, which is guided on a rail 10 and which carries a photo-electric device for scanning the sound-record. The scanner comprises a lamp 11, an optical system 17, 18, and a photo-electric cell 19. In order to traverse the scanner longitudinally along the record, the inner end of the frame 9 carries a block 8 engaging in a groove 7a in the cylinder 7, Fig. 5, by which, as the cylinder rotates, the block, together with the frame carrying the scanning- device, is moved axially along the cylinders. Thus, the record track on the rapidly rotating cylinder 14 is scanned by the light passing through it from the lamp 11. The groove 7a is continuous, and changes the direction of its pitch at each end of the cylinder, so that the frame 9 is reciprocated. The photo-electric cell 19 is connected in the input of an amplifier which operates a loud-speaker, a suitable circuit being described and shown. Switching mechanism, operated by the clock, is provided to condition the amplifier for operation shortly before each time the passage of light through the sound-track is required to activate the photo-electric cell. For this purpose, a rotary contact arm driven by the clock bridges contacts in the circuit of the transformer which supplies current to the valves, before closing a circuit through the exciter lamp. In a modification, the contacts first closed by the clockdriven switch operate a low-voltage relay by which the transformer supplying the amplifier is energized. Instead of the optical system shown an elongated lamp with a movable shutter may be provided. The apparatus described may be used for announcing time, by speech or by chimes &c. for sounding an alarm, or for' making other announcements or signals, at predetermined times.