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Magnetic Configuration for Hall Sensor Emitter Wheel

IP.com Disclosure Number: IPCOM000080558D
Original Publication Date: 1974-Jan-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 44K

Publishing Venue

IBM

Related People

Braun, RJ: AUTHOR [+2]

Abstract

The emitter wheel comprises two identical pole plates 1 and 2, Fig. 1, with an appropriate number of fingers which are bent at right angles, so that they overlap and are spaced equally, as shown in Figs. 2 and 3. The pole plates are stamped out of flat sheet metal and bent in the same or a subsequent operation. The permanent magnet 3 may be of any material like INDOX*, CERAMAGNET**, etc., that has a high H to B ratio which lends itself to be used in a thin-disc form.

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Magnetic Configuration for Hall Sensor Emitter Wheel

The emitter wheel comprises two identical pole plates 1 and 2, Fig. 1, with an appropriate number of fingers which are bent at right angles, so that they overlap and are spaced equally, as shown in Figs. 2 and 3. The pole plates are stamped out of flat sheet metal and bent in the same or a subsequent operation. The permanent magnet 3 may be of any material like INDOX*, CERAMAGNET**, etc., that has a high H to B ratio which lends itself to be used in a thin-disc form.

The assembled emitter wheel provides strong, oppositely polarized magnetic poles around its periphery, which can be sensed with a regular type Hall sensor or similar magnetic pickup device. For an optimal design of minimum size and cost, a Hall sensor 4 shown in Fig. 3 is provided with a Hall chip mounted within a two sided symmetrical magnetic path.

This emitter wheel can be used for "paper jam" detection. It would have a thin coat of rubber-like plastic forming a skin around its periphery, on which it rides on the paper as a friction coupled wheel. Any movement of the paper will be transformed in a rotary movement of the emitter wheel and can be sensed. Whenever the paper advances a defined distance, like one line spacing, the emitter wheel is turned by the equivalent amount and one or several switching pulses may be generated by the Hall sensor. This can be used to detect a "paper jam" condition where the paper does not advance when an advance c...