GB337094A - Improvements in, or relating to, electrical sound reproducing apparatus - Google Patents

Abstract

337,094. Colassi, W. L. Jan. 29, 1930. Magnetic instruments. -The reed of a loudspeaker or other soundreproducing apparatus of the kind which comprises a diaphragm operatively connected with a reed having lateral supporting arms under tension and supporting the reed in a magnetic field is directly mounted by the extremities of its supporting arms 29a in such manner that tension is applied to to the arms during the act of mounting. The arms 29<a>, Fig. 1, may be integral with the armature portion 29 of the reed and disposed and tensioned in the same plane as the armature, and may be arranged in the form of a T, X, or Y with the central portions 32 of the arms apertured or reduced in thickness for lightness. The ends of the arms 29a are clamped by nuts 26 to bolts 21 which are secured at their lower ends to a base 2 of non-magnetic material, the bolts being spaced slightly further apart at their lower ends than the holes in the arms of the reed so that tension is applied to the reed when the securing nuts 26 are tightened. A platform 5, to which a horseshoe magnet 17 with pole pieces 19 and voice coils 22, is clamped is pivotally attached bv trunnions 6 to pillars 3 carried by the base 2. Small springs 8, 9 tend to turn the platform 5 about the pivots 6 in one direction against a much stouter spring 10 on the opposite side of the pivots, a set screw limiting the movement. The platform and magnet are adjusted relatively to the reed by a screwed rod 11 screwed to the platform 5 and passing through a bush or sleeve 13 carried by the base 2. A lock nut 14 is provided for mounting the unit, which is enclosed in a dust-proof cover. In a modified construction of reed, Fig. 17, two reeds 29a similar in construction to the ones described above are superimposed and spaced apart at their outer ends and are placed in further and adjustable tension by drawing them together at the centre.