GB775795A - Arrangement for magnetically recording sound on and reproducing it from a magnetizable disk - Google Patents

Abstract

775,795. Magnetically recording and reproducing sound; magnetic sound record discs. SVENSKA AKTIEBOLAGET GASACCUMULATOR. April 19, 1955 [April 21, 1954], No. 11263/55. Class 40 (2). In an arrangement for magnetically recording and reproducing sound on a magnetizable rotatable disc 1 by a magnetic recording and reproducing head 5, 6 which is guided along a spiral recording path by a spiral guiding groove 2 or 3 formed on each side of the otherwise plane surface of the disc, the width, in the radial direction of the disc, of the part of the head abutting the disc equals the sum of the width of a groove turn and of the part 4 of the plane surface lying between two adjacent turns whereby in operation the said head part abuts a constant radial width of disc surface irrespective of the position of a groove turn or of parts of two adjacent groove turns below the head. The width of a groove turn is equal to that of the part of the plane surface lying between two adjacent turns. The two grooves 2, 3 may run in such direction that, viewed from one side of the disc they cross one another continually; alternatively they may run parallel to one another in which case in the radial direction they may be arranged either opposite one another or be displaced as shown. The magnetic material not shown on the parts 4 may descend into the grooves 2, 3, and the guide wheel 7 by which the head is guided radially engages a groove on the opposite side of the disc from the head.