Heat diffuser for magnetic tape drive

A magnetic tape drive for reading and writing data on magnetic tape in a cartridge of the type in which a driven roller in the cartridge moves tape past a read/write head in the drive and has a tape drive motor with a fan blade assembly which draws cooling air over the baseplate of the cartridge.

BACKGROUND OF THE INVENTION 
This invention relates to a magnetic tape drive and more particularly, to a 
diffuser for removing heat from a tape drive. 
U.S. Pat. No. 5,210,664-Perona shows a tape drive for use with so-called 
"Mini-Data" cartridges. There are standards for these drives so that 
drives manufactured by different companies can read and write data 
interchangeably. These standards are referred to as the "QIC" 
(Quarter-Inch Cartridges) standards. One set of standards is referred to 
as the "QIC-80 Standards for 250-800 megabyte products." Recently, a new 
wide tape cartridge referred to as "TRAVAN" has been announced for use 
with such drives. The Travan cartridge has a metal base plate which is a 
reference for all cartridge/drive interface specifications. It is 
important to minimize thermal variations in the cartridge. The Traban 
cartridge has increased data capacity so this cartridge may be in the 
drive for extended periods of time making thermal gradient control more 
difficult. 
These drives are typically mounted in a cabinet and rack containing a 
personal computer and peripherals. In such use, the dissipation of heat 
from the cartridge and the tape drive is a particular problem. 
U.S. Pat. No. 5,014,141-Gervais is typical of prior art heat dissipation in 
magnetic tape drives. This patent shows a tape drive having a cooling 
blower for circulating cooling air within air ducts in the tape drive. 
Prior commercially available tape drives have air circulated by fans 
driven by the tape drive motor. These include the Cipher DC 3000 XL drive 
and Model 06-31-004-01 drive made by Mountain/Summit. 
It is an object of the present invention to provide improved heat 
dissipation in a magnetic tape cartridge and drive. 
SUMMARY OF THE INVENTION 
In a magnetic tape drive of the type in which a driven roller in the 
cartridge moves tape past a read/write head, the tape drive motor has a 
fan blade assembly which circulates cooling air. The air flows past the 
baseplate of the cartridge to minimize thermal gradients which might 
otherwise cause changes in the critical dimensions of the cartridge. The 
metal baseplate is a convenient way to remove heat from the cartridge. 
The tape drive motor has a drive shaft for a drive roller which engages the 
driven roller in the cartridge. The motor is mounted under a chassis with 
the fan assembly beneath the chassis. The cartridge is inserted over the 
chassis. Cooling air flows beneath the cartridge baseplate to cool the 
cartridge. The air is drawn by the blade assembly under the chassis and 
out through the rear of the pan in which the chassis is mounted. 
The foregoing and other objects, features and advantages of the invention 
will be better understood from the following more detailed description and 
appended claims.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Tape drives of this type are for use with cartridges 10 having a metal 
baseplate 10a. The drive includes a drive roller 11 which engages a driven 
roller in the cartridge to move magnetic tape in the cartridge. The tape 
is read by a magnetic head 13 in the drive. 
The drive roller 11 is driven by a motor 14 which has a drive shaft 15. 
In accordance with the invention, a fan assembly including blades 16 is 
rotated by drive shaft 15. The fan assembly circulate air beneath the 
molded, one-piece chassis 17. The motor 14 is mounted beneath the chassis 
17 with the fan assembly 16 also beneath the chassis. Motor 14 is mounted 
to the chassis 17 by a spring retainer clip 24 over motor plate 18 (FIGS. 
2, 3 and 6). The chassis 17 is snapped into the pan 19. Sheet metal 20 
rests on the ribs 21 (FIG. 3) in the pan 19. 
The air enters the bezel 12 in the front of the drive, it flows over the 
front portion 22 of chassis 17. This air flow is directed across baseplate 
10a of cartridge 10. This cools cartridge 10 at its interface 10b with 
front portion 22 of chassis 17. Fan assembly 16 draws air down beneath 
chassis 17. The air exits through the vent holes 23 in the rear of pan 19. 
In this way, cooling air circulates through the area directly beneath 
cartridge baseplate 10a. Using the motor 14 to circulate air saves the 
costs of having a separate fan and motor. Drawing air over the baseplate 
10a of the cartridge cools the cartridge efficiently and helps minimize 
changes in critical dimensions otherwise caused by thermal gradients. 
Various modifications may be made to the preferred embodiment. The appended 
claims are, therefore, intended to cover all such modifications within the 
true spirit and scope of the invention.