244,138. Burke, J. B. Butler-. June 13, 1924. Electric type actions; sound and electr@c-wave-controlled and record-controlled driving-mechanism. - Relates to apparatus for selectively controlling a series of electromagnets (1) by printed or written letters or signs, (2) by spoken letters or monosyllables or other sounds, and (3) by a keyboard. The electromagnets may actuate the levers of a typewriter or typesetting or like machine or the control levers of machines such as electric dynamos and motors in ships and railways. The apparatus is applicable to the copying of printed, typewritten &c. signs, to the conversion of such signs into Braille type or Morse code, and to the automatic printing of telephone messages. Wireless signalling may be used to give distant control. (1) A beam of light varying in intensity with or without variations in direction and produced by one or more lamps 5, Figs. 1 and 4, by one or more radial slits 55 at various slopes in a screen and by a stroboscopic wheel 7 close to the screen is focussed on signs 3 exposed singly and successively and is reflected, transmitted, or scattered on to one or more selenium or lead-antimony sulphide or like cells 6 in circuit with a telephone 9. The current variations through the cell 6 depend on the arrangement of black and white in the exposed sign, and for each sign a characteristic harmonic partial of such variations may be found by testing with an oscillograph and harmonic analyzer. The partials are uniquely selected by tuning forks 15 to which the sound from the telephone 9 is led by tubes 13. One limb of each fork carries a pin contacting with the membrane of a telephone 16, the current in the telephones being amplified by relays or thermionic valves 20 and passed with or without the intervention of a microphone 28 through transformers 29. The secondaries 31 of the transformers 29 are in individual circuits tuned by condensers 32 and inductances 33, a thermal detector 34 in each circuit decreasing in resistance and allowing the operation of a corresponding electromagnetic relay 37 by a battery 27 when the circuit resonates, and the relay closing the circuit of a corresponding electromagnet 41. The electromagnets 41 may operate the levers of a typewriter, one fork 15, one tuned circuit, and one electromagnet being affected by each sign. Instead of light, radium rays or other electromagnetic radiations may be used, the sign being correspondingly formed, for example, in ink containing lead. The wheel 7 has apertures bounded by sine curves to give harmonic variations in the light and arranged along concentric circles or along a spiral emanating from the centre of the wheel. The light may be focussed on selenium cells by lenses. Two cells may be used and connected differentially as in the optophone described in Specification 134,675. [Class 146 (ii), Stationery &c.], one cell being exposed to light affected by the sign and the other to similar light unaffected. Clockwork is provided operating a rack to move intermittently the surface on which the signs are printed. During the movement, light is cut off from the signs by a screen with circumferentially arranged apertures intermittently rotated by the clockwork or by a screen oscillated by the clockwork or by a rotary switch controlling the circuit of the lamps 5. The tuning forks may be dispensed with. a secondary coil around the coil at 9 being connected between the grid and filament of the first valve 20, or telephone receivers at the ends of the tubes 13 being included directly in the tuned circuits, which may also include the electromagnets 37. Instead of operating the electromagnets 41 directly, the relays 37 may insert resistances 43, Fig. 12, in parallel with each other into the circuit of a deadbeat d'Arsonval galvanometer 47, the pointer of which by direct contact with studs 49 or by light reflected on to selenium cells allows energization of one of the electromagnets 41, the inductance of the electromagnets or of coils inserted in their circuits preventing their energization except for a steady deflection. A combination of partials instead of a single partial may then characterize each sign, a definite deflection of the galvanometer corresponding to each sign. (2) The apparatus described in (1) modified as in Fig. 12 and with the. parts 3 - - 7 omitted may be controlled by sounds spoken, or reproduced from a wax record, into a mouthpiece 9, a characteristic partial or combination of partials of the sound being chosen for each letter, monosyllable, or other sound and being selected by the tuned circuits with or without the tuning forks. (3) A keyboard may control the apparatus shown in Fig. 1 with the parts 3 - - 13 omitted and modified as in Fig. 12, the keys closing the circuits of electromagnets or otherwise operating hammers striking the forks 15. One typewriter or keyboard may then control a number of other typewriters &c., from a distance if the oscillations of the valves 20 are transmitted by wireless. Specification 10368/14. [Class 146 (ii), Stationery &c.], also is referred to.