ELECTROMAGNETIC TRANSDUCER APPARATUS USING DC MAGNET INPUT AND ELECTROMAGNETIC PICKUP COIL OUTPUT

摘要

1294150 Displacement encoder; indexing magnetic disc records MEMOREX CORP 29 May 1970 [5 June 1969] 25938/70 Headings G4H and G5R A stack of magnetic storage discs has a bottom indexing disc 18 of aluminium with indexing slots 21 around the periphery. A transducer for detecting the slots has a plastics casing 11 enclosing a permanent magnet 13 and a coil 14 positioned on either side of a slot 17 through which the edge of the disc passes. The coil detects changes in the eddy currents induced in the disc as a slot passes through the field of the magnet. A D.C. operated coil may be used and the magnet or coil may be on the same side of the disc as the pick-up coil 14.