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Browse Prior Art Database

Non-Contact Analog Rotary Position Sensor

IP.com Disclosure Number: IPCOM000043138D
Original Publication Date: 1984-Jul-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 2 page(s) / 33K

Publishing Venue

IBM

Related People

Griffing, BM: AUTHOR

Abstract

A simple method of constructing a rotary position sensor is provided that lacks the wear associated with rotary potentiometers. The device includes a permanent magnet 10, a Hall effect device 12 and amplifier, and a closed magnetic circuit comprised of a specially profiled cam 13 and return path, which includes case 14, as shown in Figs. 1 and 2. The cam 13, constructed of soft electrical iron, can be rotated in the case 14, which is also constructed of soft electrical iron. The magnetic flux emanating from the permanent magnet 10 passes through the Hall effect device 12 into the rotating cam 13, thence into the case 14 to return to the magnet 10. The space between the end of the cam and the case is held to a very small value.

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Non-Contact Analog Rotary Position Sensor

A simple method of constructing a rotary position sensor is provided that lacks the wear associated with rotary potentiometers. The device includes a permanent magnet 10, a Hall effect device 12 and amplifier, and a closed magnetic circuit comprised of a specially profiled cam 13 and return path, which includes case 14, as shown in Figs. 1 and 2. The cam 13, constructed of soft electrical iron, can be rotated in the case 14, which is also constructed of soft electrical iron. The magnetic flux emanating from the permanent magnet 10 passes through the Hall effect device 12 into the rotating cam 13, thence into the case 14 to return to the magnet 10. The space between the end of the cam and the case is held to a very small value. The variable gap 15, caused by rotating the cam, will cause changes in flux density experienced by the Hall device 12 whose output goes to an amplifier (not shown). Proper cam design will create an output linearly proportional to the angular displacement of the cam.

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