Patent GB-918000-A (GB)
Title: Improvements in magnetic memory devices
IPC: G11C5/02
Filed: 1961-07-14
Abstract: 918,000. Magnetic information-storage apparatus. AUTOMATIC ELECTRIC LABORATORIES Inc. July 14, 1961 [Aug. 24, 1960 (2); Oct. 27, 1960; Jan. 6, 1961], No. 25666/61. Class 40 (9). The ring cores of a magnetic matrix store are positioned vertically with respect to a stack of printed-circuit insulating sheets which support the cores. In one arrangement, Fig. 2, each core 12 is positioned in a sheet aperture 20 about a tongue 13A which extends a printed conductor 11 through the core. The printed conductor interrupted by the aperture is bridged by a short printed conductor in the next insulating sheet of the stack, as shown for example at 7C and 7D in Fig. 4. The cores and stack of sheets 10 are assembled by mounting the cores vertically in a jig 23, placing the stack of sheets 10A-10D over the cores with their tongues extending alternately in opposite directions as shown in Fig. 6, and sliding the stack of sheets inwards so that the tongues lock the cores in position. The inner sheets 10B, 10C have printed conductors on both surfaces. Assembly is completed by applying a heated press tool 24 which causes solder at the ends of the printed sections to melt and so complete the printed conductor circuits. When cooled, the soldered connections secure the assembled stack of sheets and cores which is removed from the jig. In a modification, Fig. 8, each printed circuit is shared between the adjacent surfaces of the insulating sheets, and the number of soldered connections required is therefore halved. An alternative form of sheet is shown in Fig. 5 which has provision for mounting two groups of orthogonally positioned cores, successive sheets in the stack having printed circuitry for alternate groups of cores. An alternative matrix is described, Fig. 13, in which comb-like insulating sheets 213 are threaded through the cores and apertured sheets 210 are placed over the cores. The sheets 210, 213 are applied alternately so that brief circuit sections 215 on the limbs of the sheets 213 complete the printed wiring circuits on sheets 210. In a modification, Fig. 14, all the sheets may be in the form of the comb-like members 213, 219 shown. A different method of construction is used in Figs. 10 to 12 in which a stack of insulating sheets 110-113 is assembled by adhesive after depositing the sense winding 14 and co-ordinate windings 15, 16 with the aid of stencils 125. The deposition process may make use of a silver nitrate solution with the addition of a reducing agent which is precipitated on to the insulating sheets. This process may be repeated several times or followed by electrolytic deposition. The assembled stack of sheets is then perforated at 121 and pairs of holes are exposed by stencils 124 temporarily placed on each side of the stack. The storage cores 122 are then formed by first depositing a metal such as copper on the stack by a chemical reduction process. This is followed by electrolytic deposition of the magnetic core material, using the deposited copper as a cathode and the magnetic material as an anode. When sufficient depth of magnetic core is obtained the stencils are removed.