GB277052A - Improvements in or relating to a device for converting electric oscillations into mechanical vibrations - Google Patents

Abstract

277,052. Wade, H., (Naamlooze Vennoots. chap Philips' Gloeilampenfabrieken). May 7, 1926. Magnetic instruments. -A device for converting electrical oscillations into mechanical vibrations, more particularly for use in loud-speakers, comprises a ferromagnetic element movably provided within a permanent magnetic field and polarized by a surrounding immovable winding or windings, the element being adapted to move alongside the magnet pole-shoes so that the width of the air-gaps remains unvaried. Fig. 1 shews a construction employing an H-shaped armature having its ends located between the unlike poles of two horseshoe magnets 1, 2, the neutral points of which are connected by a magnetic yoke 3. A stationary coil 7 surrounds the yoke 6 connecting the legs 4, 5 of the armature, which is guided rectilinearly by bifurcated rods 8 passing through guides 9. One of the rods 8 carries at its end a cone 10. In the modified construction, Fig. 5, a double T-shaped armature 4, 5, 6 is rotatably mounted on a shaft 11, the yoke 6 being surrounded by two stationary coils 7. The pole-shoes of the magnets 1, 2, which have their poles of like nature oppositely disposed on a magnetically conducting yoke 3, are turned out concentrically to the shaft 11 so as to leave only a very narrow air gap between the poles and segments 4, 5. The neutral points of the magnets are connected at 13. The degree of stability can be controlled, in both constructions, by regulating the iron section of the. yoke 6 relatively to that of the segments 4, 5.