GB679938A - Improvements relating to electromagnetic recording apparatus - Google Patents

Abstract

679,938. Magnetic recording apparatus. BRITISH ELECTRICAL & ALLIED INDUSTRIES RESEARCH ASSOCIATION. March 13, 1951. [March 13, 1950] No. 6280/50. Class 40 (ii). [Also in Group XIX] Magnetic recording heads 23, 24, Fig. 5, each comprising a loop of magnetic material 26 with a gap 28 and a coil 27 are supported on a recording drum 1 and at one point on a rod 31 which is mounted in a bracket comprising arms 32, 33 pivotally supported on bolts 35, 36 on axis A,B passing through the gaps 28. The angular position of the brackets about the axis A,B is adjusted by a wing nut 37 and bolt 38 working in a slot 39, to ensure that the area of contact between each head and the drum is divided in half by the gap 28. The magnetic material 26 is tapered towards the gap 28 to give a high fluxdensity across the gap. Erasing heads 45, 46 are mounted in corresponding supports and a rod 51 engages the frameworks supporting both sets of heads to ensure that the heads are properly aligned. The drum may be in two halves 2, 3, Fig. 1, each half having three pairs of recording heads spaced around the periphery of the drum. The drum is moved axially to make successive sets of recordings, by energizing a solenoid (Fig. 2, not shown). This causes a rod to rise and a pivoted pawl on the rod rotates a cam 72 having a series of steps against which a cam follower 69 fixed to an extension 60 of the drum shaft 4 engages. The follower is held in engagement with a step on the cam by a spring 71. Thus, when the cam rotates the extension 60 and the drum are moved axially. When a series of recordings has been completed, the drum is returned to its initial position by pulling the rod 60 to the right and the cam 72 is returned to initial position by a spring. A stop is provided to limit the positions to which the cam moves.