Browse Prior Art Database

Vacuum Column to Reduce Tape Wear

IP.com Disclosure Number: IPCOM000077237D
Original Publication Date: 1972-Jun-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 44K

Publishing Venue

IBM

Related People

Baumann, GW: AUTHOR [+3]

Abstract

The vacuum column walls of this magnetic tape unit include a linear air bearing surface pattern having critical dimensions which provide a lubricating film of air, without allowing excessive air flow into the vacuum source.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 82% of the total text.

Page 1 of 2

Vacuum Column to Reduce Tape Wear

The vacuum column walls of this magnetic tape unit include a linear air bearing surface pattern having critical dimensions which provide a lubricating film of air, without allowing excessive air flow into the vacuum source.

The high-speed magnetic tape unit of Fig. 1 includes two parallel-wall vacuum columns 10 and 11 and two converging-wall vacuum columns 12 and
13. One-half inch wide magnetic tape 14 forms a loop in each of these four vacuum columns as it travels at a high speed between reels 15 and 16. This tape includes a backing layer, such as MYLAR*, and a recording layer. The backing layer engages the walls of the vacuum columns.

Damage to the tape's backing layer is reduced by providing the one-half inch wide vacuum column walls of all four columns with substantially full length grooves, extending parallel to the direction of tape movement. These grooves are critically dimensioned to form a linear air bearing which holds the tape away from the column walls. This air bearing is created by the air which flows in these grooves, and down the associated column walls, into the vacuum port which is located at the bottom of each column.

The grooves, shown in section in Fig. 2, have a depth 17 which varies between a minimum of 0.006 inch (to prevent hydrodynamic clinging of the tape to wall 18 of the column) and a maximum of 0.025 inch (to avoid excessive air flow and the resulting venturi effect tending to hold the tape against w...