Improvements in or relating to magnetic heads and magnetic recorders including the improved magnetic heads

摘要

594,571. Telegraphones. ARMOUR RESEARCH FOUNDATION. May 2, 1945, No. 11129. Convention date, Aug. 26, 1944. [Class 40 (ii)] A magnetic recording and reproducing head 10 comprises a paramagnetic plate 19 having a pair of holes 21, 22 therein, and slots 23, 24 extending between the holes and an edge 20 of the plate, two coils 12, 13 each extending through one of the holes and over the slot associated therewith, one of the coils, 12, being connected to a source of H.F alternating current 14, and the other, 13, being connected to a source of audio-frequency current such as the amplifier 16, the edge 20 of the plate defining a path along which a wire 11, of high magnetic retentivity is arranged to travel. The crowned edge 20 of the plate 19 is provided with a flaring groove 29 with diverging wall portions 30, 31, Fig. 3, and with a further groove 32 having a greater radius of curvature than the groove 29 so that any enlargement on the wire will cause it to ride up out of the inner groove 32 thus preventing jamming. The plate 19 is retained between two plates 33, 34 of insulating material, each having holes 35, 36 slightly smaller than the holes 21, 22 and concentric therewith. The upper edge 37 of each insulating plate is notched as at 38, 39 to receive the coils. The wire travels in the direction indicated in Fig. 1 and is demagnetized by passing through the highly concentrated field set up by the coil 12 between the polar portions 25, 26. The record is then made as the wire passes through a magnetic field which is the resultant of the A.F. exciting current in the coil 13 and the stray field in the vicinity of the polar portions 27, 28 due to the H.F. current in the coil 12. Reproduction takes place by reversal of the direction of travel.