GB1488541A - Loudspeaker - Google Patents

Abstract

1488541 Loud-speaker diaphragms W L REHDE and J A REHDE 23 July 1975 [12 Aug 1974] 30727/75 Heading H4J In a moving coil loud-speaker a central stiffening ring 4 of material is adhered firmly to both the diaphragm and voice coil former and, beyond the ring 4, stiffened zones 7, 8, 9, 10 are produced by impregnation with a hard-setting varnish, these zones 7, 8, 9, 10 being independent of one another and extending outwards to the outside edge of the diaphragm. Preferably the hardsetting varnish is of cellulose type and the central stiffening ring 4 is of hard setting adhesive. Preferably an annular coating layer 5 of varnish surrounds the annular zone. A corrugated spider (3) Fig. 1 (not shown) is provided. The zones 7, 8, 9, 10 may be reinforced by additional cloth, paper or other material bonded by the varnish. In alternative arrangements three regions (11) Fig. 4 (not shown) are used or four strips extend from the layer 5 to the periphery of an elliptical diaphragm. Fig. 6 (not shown) shows the part of the diaphragm outside the annular layer 5 entirely covered by varnish except for four strips (13) arranged at right angles to each other. In Fig. 7 (not shown) four narrow arcuate strips (14) of varnish are used. In Fig. 8 (not shown) eight radial strips (15) extend from the annular layer 5 to the periphery. All arrangements may be applied to diaphragms of elliptical or any other non-circular shape.