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Browse Prior Art Database

Magnetic Slot Encoder

IP.com Disclosure Number: IPCOM000078296D
Original Publication Date: 1972-Dec-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 3 page(s) / 42K

Publishing Venue

IBM

Related People

Coker, CW: AUTHOR [+4]

Abstract

This apparatus 10 is arranged to record digital data at constant density on a card 12, having a magnetic record stripe 14, as the card 12 is moved through a slot 16 by hand, at a velocity which may vary considerably because of human factors.

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Magnetic Slot Encoder

This apparatus 10 is arranged to record digital data at constant density on a card 12, having a magnetic record stripe 14, as the card 12 is moved through a slot 16 by hand, at a velocity which may vary considerably because of human factors.

The device 10 is arranged to support a bearing, not shown, which encompasses a shaft 28 and allows the latter to rotate freely. A friction roll 30 is arranged on one end of the shaft 28 at one side of the slot 16, and protruding slightly therein. A recording transducer 32 is arranged on the other side of the slot 16 and spring loaded to bear against the roll 30. The spring loaded transducer urges the card 12 against the roll 30, causing the latter to rotate with a peripheral velocity equal to the card velocity.

Attached to the shaft 28 is a disk 34, which has 8 mil wide timing marks in the form of apertures spaced on 16 mil centers located around the circumference of the disk 34.

The disk 34 rotates between the light source (light-emitting diode) on one side of the disk and a phototransistor on the other side of the apertures. The phototransistor and the light-emitting diode are arranged in housings 36, 38. As the disk 34 rotates, the phototransistor is turned on by light passing through the timing apertures.

The phototransistor signal is detected by a photoamplifier, not shown, that produces clock pulses at the amplifier output that are used to clock write data from a message register to the transducer 32, for recording on the magnetic stripe 14. A clock pulse is generated every four mils of card displacement. Therefore, the clock rate is proportional to the speed of the card 12 through the slot 16 and a constant recording density is mainta...