Browse Prior Art Database

Vacuum Controlled Transducer

IP.com Disclosure Number: IPCOM000091381D
Original Publication Date: 1968-Jan-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 3 page(s) / 49K

Publishing Venue

IBM

Related People

Bradford, RC: AUTHOR [+4]

Abstract

U.S. Patent 3,327,916 shows a magnetic transducer arranged to maintain a controlled thickness air film between its operating surface and a magnetic record tape moved over it. The transducer shown above makes use of the arrangement in the patent with an operating surface contoured to reduce separation variations caused by particles carried between the tape and the transducer.

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Vacuum Controlled Transducer

U.S. Patent 3,327,916 shows a magnetic transducer arranged to maintain a controlled thickness air film between its operating surface and a magnetic record tape moved over it. The transducer shown above makes use of the arrangement in the patent with an operating surface contoured to reduce separation variations caused by particles carried between the tape and the transducer.

The operating surface includes flat central portion 1 with leading and trailing portions 2 and 3 extending from it at a small bevel angle a. Each surface 2 and 3 is joined to the central portion by a curved portion having a small radius r, so that a smooth and continuous surface results. Working gaps 4 and 5 of the transducer are positioned in the curved portions. Transverse vacuum slots 6 and 7 are provided near the ends of the transducer in surfaces 2 and 3 as shown in the patent.

The recording tape, not shown, is guided over the transducer by guides which cause it to wrap at an angle b, smaller than a, with respect to the central portion 1. When no vacuum is applied to slots 6 and 7, as in a rewind operation, small radius r on the upstream side of portion 1 acts to build a lubricating hydrodynamic air film between the tape and the transducer to prevent contact. When vacuum is applied, the tape is drawn down toward surfaces 2 and 3 and a controlled separation is achieved in the manner shown in the patent. This separation is reduced somewhat, as the tape passes over the radius r, by the presence of small longitudinal grooves 8 extending between gaps 4 and 5. Grooves 8 channel a portion of the air forming the hydrodynamic bearing and reduce the thickness of the film at the area of gaps 4 and 5.

Longitudinal side grooves 9 connect with the vacuum slots and extend toward the working gap area of the transduce...