GB907955A - Magnetic recording head structure - Google Patents

Abstract

907,955. Magnetic recording &c. heads. SYLVANIA ELECTRIC PRODUCTS Inc. June 2, 1961 [June 24, 1960], No. 20035/61. Class 40 (2). [Also in Group XXII] A magnetic recording head is made by evaporating a layer of magnetic material on to a support and by then cutting an air gap. The support, preferably of glass tubing, is first masked into bands, where a stacked head is to be made, and a preliminary, tenacious coating of about 1 Á thickness of an iron-rich nickel/iron alloy deposited, followed by a layer of 10 to 25 Áthickness of a nickel-rich alloy. The region which will be away from the gap may also carry an additional thickness of alloy. The gaps are produced in line across all the component heads by a diamond cutter. It is found that the gap spacing is related to the deposited thickness so that gaps narrower than the thickness of the deposit may be produced by controlled electrolytic build-up. As an alternative, the gaps may be etched. Compared with conventional heads, the thin poles have low leakage inductance and low fringe fields. In Fig. 3, the support is in two parts; the bands 32 are continued diametrally inwardly on the curved member 30, which is clamped to a striped flat member 48, gapped at 56 to provide space for windings and inter-winding screens (not shown). In Fig. 4, a circular glass tube is provided with winding apertures 78 opposite the gaps 24.