GB215719A - Speaking trumpet and sound receiver of the azimuth-measuring type - Google Patents

Abstract

215,719. Perrin, J. B., and Marcelin, A. J. May 12, 1923, [Convention date]. Sound magnifying and directing appliances. - A combined speaking and soundreceiving trumpet comprises a sound collecting or transmitting horn 1, Fig. 3, the conduit 6 of which can be put into communication either with a tube 8 leading from a mouthpiece 18, Fig. 2, or with a tube 9 leading to an earpiece 22, by means of a switch member 11 rotatable axially by means of a knob 13. In order to locate the direction of received sounds or to send the voice in a particular direction, the whole apparatus is rotatable vertically upon a pedestal 3 and is provided with sighting means 23 and a pointer and scale 5. A small horizontal rotation about an axis 24 is also permitted'. In a modification, Fig. 5, the horn comprises four elements 25, the central passages 26 of which unite in a common passage 27. Fig. 8 shows a modified switch member for use with two earpieces and two horn members of the type shown in Fig. 5. In the position shown, passages 44, 45 connect the pipes 31 leading from the horns to separate earpiece tubes arranged adjacent to the apertures 46, 47, whilst with the switch device rotated through 90‹, the passage 40 (shown in dotted lines) connects the tubes 31 with a single central tube leading from the mouthpiece. The horn elements 1, 25 are formed as solids of revolution so that incoming sound waves traverse equal paths on their way to a central collecting tube.