Digital Equipment Corporation

Edward Courtney, Jr

Patrick L Hearn

A method of manufacturing a magnetic tachometer used to generate a signal as a function of the velocity of a transducer positioning arm in a disk drive. The tachometer is formed over a one piece plastic insert having a first and second portion separated by a central breakaway region. An armature member is disposed over each of said first and second insert portion and a flexible connector is placed on a groove cut on a surface of said plastic insert. Two coils are simultaneously wound over said first and second insert portion, respectively, and connected to the flex connection. The insert is then bent to snap the breakaway region, and the resulting two coil subassemblies are folded and fastened to spacers to form a pair of fixed parallel coils. The separation between the coil is maintained at a predetermined value by the spacers to allow a magnet, attached to a counterbalance portion of a rotary positioning arm, to move therebetween and thus to generate a voltage as a function of the velocity of the magnet.

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Pepperell, MA, United States of America

Edward Courtney, Jr