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Vacuum Operated File Protect Switch Assembly

IP.com Disclosure Number: IPCOM000078500D
Original Publication Date: 1973-Jan-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 53K

Publishing Venue

IBM

Related People

Kellow, RE: AUTHOR

Abstract

This switch assembly includes a vacuum operated actuator, which is energized when a sensing pin mechanically engages a file reel's write-enable ring. The actuator then pulls the pin out of engagement with the ring, to prevent wear as the reel subsequently rotates. This movement of the sensing pin also closes an electrical switch and thereby activates an associated magnetic tape unit's write circuits, allowing data to be written on the reel's magnetic tape.

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Vacuum Operated File Protect Switch Assembly

This switch assembly includes a vacuum operated actuator, which is energized when a sensing pin mechanically engages a file reel's write-enable ring. The actuator then pulls the pin out of engagement with the ring, to prevent wear as the reel subsequently rotates. This movement of the sensing pin also closes an electrical switch and thereby activates an associated magnetic tape unit's write circuits, allowing data to be written on the reel's magnetic tape.

A reel 4 carrying one-half inch magnetic tape is mounted to rotate about axis 2, by means not shown. The reverse side of the reel includes annular groove 3 which is adapted to hold a write-enable ring, not shown. This ring serves the purpose of protecting the magnetic tape from inadvertent writing thereon, since it is only the presence of a ring in groove 3 which activates the write circuits associated with the tape unit's write head.

Electrical switch 4 is controlled by the position of sensing pin 5. When a ring is present in groove 3, pin 5 is moved to the right, causing switch 4 to close, and activating the write circuits. Pin 5 is spring biased to the left, by switch actuator 6 which is coupled to annular groove 7 carried by the sensing pin 5.

Movement of the sensing pin to the right, as above mentioned, also energizes vacuum actuator 8. This actuator includes valve 9 and piston 10, both of which are integral parts of the sensing pin. Both valve 9 and piston 10 a...