Browse Prior Art Database

Motor Mount and Shield for Miniaturized Portable Recorder

IP.com Disclosure Number: IPCOM000084178D
Original Publication Date: 1975-Oct-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Frankeny, RF: AUTHOR [+2]

Abstract

In a miniaturized battery operated portable recorder having a soundhead in close proximity to a drive motor, an induced magnetic field can be caused by motor commutation and heard as noise through the soundhead. This noise can be eliminated by a magnetic shield which serves as a motor mount.

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Motor Mount and Shield for Miniaturized Portable Recorder

In a miniaturized battery operated portable recorder having a soundhead in close proximity to a drive motor, an induced magnetic field can be caused by motor commutation and heard as noise through the soundhead. This noise can be eliminated by a magnetic shield which serves as a motor mount.

Motor 1 is mounted interior of cylinder 3 and sleeve 4. Cylinder 3 is closed at one end and secured to a drive mounting frame 2. Motor 1 is positionably maintained within cylinder 3 and sleeve 4 by a standard resilient O-ring 5. Ring 5 prevents motor vibrations from being transmitted to the recorder.

Cylinder 3 and sleeve 4 form the magnetic shield. Sleeve 4 is of high permeability. Cylinder 3 is made of an inexpensive and readily machineable electrical iron. The air gap distance between motor 1 and cylinder 3 is determined by the spacing between the motor and the soundhead. This distance is maximized in order that the shield enclose the lowest possible field strength. Sleeve 4 provides a low-reluctance path for the majority of magnetic flux leakage. Cylinder 3 contains the end flux.

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