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Optical Flat for Measuring Tape Wrap Angle

IP.com Disclosure Number: IPCOM000037843D
Original Publication Date: 1989-Jul-01
Included in the Prior Art Database: 2005-Jan-30
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Hu, PY: AUTHOR [+4]

Abstract

Optical flats can be used to directly measure the mechanical dimensions of a magnetic head and its relationship to tape guides. The dimensions that can be measured are the gap to the air bearing slots in the head, the gap to the tangent of the tape to the head and the air bearing slots to the tangent of the tape to the head and guide. The measured dimensions can be used to determine the wrap angle of the tape across the head in both the forward and reverse directions of the tape with respect to the head.

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Optical Flat for Measuring Tape Wrap Angle

Optical flats can be used to directly measure the mechanical dimensions of a magnetic head and its relationship to tape guides. The dimensions that can be measured are the gap to the air bearing slots in the head, the gap to the tangent of the tape to the head and the air bearing slots to the tangent of the tape to the head and guide. The measured dimensions can be used to determine the wrap angle of the tape across the head in both the forward and reverse directions of the tape with respect to the head.

As shown in the Figure, a magnetic head 1 has an optical flat 2 placed at positions A, B and C to obtain the head dimensions. In position A, the optical flat 2 bridges from a tape guide 3 to a tangent point 4 which is the place where the tape will contact the slots 5 of the write head 6. At position A, the optical flat 2 can determine the contact of the tape with respect to the slots 5 and the write gap 7.

At position B, the tangent point 8 at which the tape leaves the write head 6 and contacts the slots 9 of the read head 10 at tangent point 11 can be determined as well as the distance between the tangent point 8 and the write gap 7 and the tangent point 11 and the read gap 12. With the optical flat 2 at position C, the wrap angle of the tape as it leaves the slots 13 of the read head 10 at tangent point 14 and the tangent point 15 where the tape contacts the tape guide 16 can be determined. Since the magnetic tape can...