| 摘要 |
<p>986,390. Electrodynamic transducers; diaphragms. G. R. POUTOT. June 22, 1961 [June 23, 1960], No. 22725/61. Heading H4J. A rigid diaphragm for a loud-speaker or microphone has, a specific gravity of less than 0À1, one plane side and on its opposite side at least one protrusion which carries a conductive member disposed in a magnetic field. The diaphragm 1a consists of a foamed polystyrene rectangular sheet (specific gravity less than 0À02) of dimensions 120 x 80 x 6 mm. and it has a number of parallel grooves 14 formed in one face thereof. An aluminium wire 2a or ribbon (Fig. 3, not shown) is glued to the projecting ribs 15 so as to form a number of rectangular loops (Fig. 11, not shown). The magnet system comprises a number of sheet-metal laminations 22, 23 of high permeability which are glued to plates 24 of a magnetic ferrite material, the individual " magnets " so formed being retained in a framework 18a, 18b, 25a, 25b. The diaphragm la is positioned and supported above the magnets by flexible strips 12a, 13a of foamed P.V.C. or polyurethane. Stranded leads 16 connect insulated terminals 20a, 20b to the coil (2a). The use of triangular shaped and trapezoidal diaphragms is discussed with reference to Figs. 4, 5 and 8, 10 respectively (not shown) and a number of conventional circular coils are used on a diaphragm described with reference to Figs. 13 and 14. It should be noted that for any free point on the plane side of the diaphragm a cone can be drawn with its vertex at the junction of a protrusion and the main portion of the diaphragm, with its axis at right angles to the plane of the diaphragm and with a vertex angle of less than 100 degrees such that the free point lies within the cone.</p> |
