GB261506A - Improvements in and relating to apparatus for transmitting or reproducing sound - Google Patents

Abstract

261,506. Brown, S. G. Sept. 19, 1925. Loud-speakers ; magnetic instruments.-In a toud-speaher of the kind in which a vibrating reed is attached to a diaphragm, means are provided for adjusting the position of the reed so as to regulate the air-gap in the magnetic circuit. In the form shown in Figs. 1 and 2, the reed 10 is carried by a T-piece 7 which is screwed at 9 to the arms of the V-shaped magnet 1. The reed lies in the upper part of the space between the laminated pole-pieces 4, and the gap between it and them is regulated by tilting the T-piece 7 by adjusting the set-screw 12, which passes through a hole in the tail 8 of the T-piece. The deformable arms of the T-piece serve as a pivot for the movement. An adjustable reed-stop 17 is carried by a plate 16 on the under side of the magnet. In a modification the pole-pieces are solid and have screwed to their under sides three brass plates 19, 20, 21, Fig. 4, of which the middle plate is shorter than the outer two. The latter carry a reed stop screw 23, and owing to their resilience they serve as a looking means to secure it during vibration. When the instrument is first assembled the pin 25 on the diaphragm may pass freely through a slot at the end of the reed 10, but after the magnets have been fixed in position the pin is soldered to the reed ; strains are avoided by this procedure which is particularly applicable to instruments of the type described in Specification 257,747.