GB297131A - Improvements in or relating to diaphragms for sound reproducing devices - Google Patents

Abstract

297,131. Waddell, B. F. May 14, 1927. Diaphragms; loudspeakers.-An acoustical diaphragm having a plurality of flexed surfaces associated in pyramidal relation is formed from a single piece of material, the surfaces being connected at their adjacent edges by folds to compensate for excess material. Fig. 3 shows one form of blank 10 from which the diaphragm may be formed. This blank is deeply notched at 11 at the corners and is creased or scored at 12, 13 and 14. The blank is then folded along the straight crease lines 13, flexed backwardly and folded along the curved crease lines 14 with the material in the spaces 17 overlapped upon the plain quadrants. A diaphragm of the form shown in Fig. 4 is thus produced with four strengthening ribs or folds 18 radiating from the stylus holder 12. The diaphragm so formed is held rigidly under tension in a groove 9 in the mouth of a casing 1, Fig. 2, by means of a clamping frame 8. As shown in Fig. 2, the diaphragm is employed in a loudspeaker, its apex being connected by a rod 4 with the armature 7 of an electromagnetic actuating unit 2. Fig. 5 shows an alternative form of blank having the corners 19 notched and slits 20, 21 cut therein. The blank is creased to produce a central area 12 and also scored along straight and curved radial lines 22, 23. When the blank is folded on the score lines and the quadrants are simultaneously flexed backwardly, the flaps 24, produced by the slits, extend under the adjacent, quadrants and are utilized for glueing the corners together and thus holding the quadrants under stress in their flexed position. Fig. 6 shows the final form of diaphragm with strengthening ribs 25, 26.