Browse Prior Art Database

Reel To Reel Unit with Decreased Acceleration Time

IP.com Disclosure Number: IPCOM000076096D
Original Publication Date: 1972-Jan-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 45K

Publishing Venue

IBM

Related People

Kollar, EP: AUTHOR [+3]

Abstract

This reel-to-reel magnetic tape unit (no capstan and no tape buffer) moves tape 10 solely by closed-loop servo energization of the two direct-current reel motors 11 and 12. An idler tachometer 13 is driven by tape movement and provides an output signal on conductor 14, which indicates tape speed. As an alternative, the tape may include a constant-frequency timing track which is read by a transducer to obtain tape speed information.

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Reel To Reel Unit with Decreased Acceleration Time

This reel-to-reel magnetic tape unit (no capstan and no tape buffer) moves tape 10 solely by closed-loop servo energization of the two direct-current reel motors 11 and 12. An idler tachometer 13 is driven by tape movement and provides an output signal on conductor 14, which indicates tape speed. As an alternative, the tape may include a constant-frequency timing track which is read by a transducer to obtain tape speed information.

The tape can be moved forward or backward under the command of input conductors 15 and 16. In either direction, the motor receiving tape functions as the take-up motor. The other motor operates during acceleration to buffer the tape and operates during steady-state constant-speed operation to maintain tape tension.

Assuming that a command is received for forward tape movement, as soon as the GO command on conductor 17 becomes active, servo network 18 energizes take-up motor 11 in accordance with the algorithm expressed by the graph of Fig. 2, and energizes supply motor 12 in accordance with the algorithm expressed by the graph of Fig. 3.

Referring to Figs. 2 and 3, the GO command becomes active at time t(0). During the accelerate interval t(0)-t(1) both motors are energized to move tape in a forward direction. During this interval, tape tension is maintained at a relatively low level to produce the effect of a tape buffer. As a result, motor 11 experiences little drag during the accele...