GB330501A - Improvements in or relating to the making of matrices for use in the manufacture of sound records - Google Patents

Abstract

330,501. Thorogood, R. P., and Good, J. Feb. 7, 1929. Records, duplicating; ribbon records.-A metal matrix in ribbon form for use in the manufacture of sound records is made by electrodeposition on to the face only of the master record f, which is also of ribbon form and is wound helically in a long length around a carrier b with its convolutions spaced apart. The record ribbon f is wound in a helical groove e which is formed in the surface of the carrier b, and a rubber &c. cord g may be wound between and over the edges of adjacent convolutions of the ribbon, as shown in Fig. 3. Alternatively, the carrier b may be of non-conducting material and have a helical rib for separating the convolutions of the ribbon f. The carrier b, of hollow cylindrical form, and an anode c, arranged around the carrier, are supported within a vessel a containing -the electrolyte. The anode c may be of tapering form and, to avoid voltage drop along the conducting surface of the ribbon f, a metal strip connected with the negative pole of the source of current supply is provided with a number of tongues, adapted to bear against the said conducting surface at different points along its length. The carrier b may be rotated by means of a belt-driven drum m, and the ribbon f may be formed of a metal adapted to serve as a cathode, or it may be coated with graphite &c. Duplicate sound records are produced from the matrix ribbon by pressing the latter, under heat if desired, with a plain ribbon of celluloid &c.