Low profile tape drive for driving a mini-data cartridge

A magnetic tape drive for driving magnetic tape in a cartridge of the type in which a driven roller in an exposed edge of the cartridge moves the tape past a read/write head in the drive. A drive roller in the drive is rotated by a motor. The drive roller engages an idler capstan which, in turn, engages the driven roller in the cartridge.

FIELD OF THE INVENTION 
This invention relates to a magnetic tape drive and more particularly, to a 
low profile drive for a magnetic tape cartridge of the type in which a 
driven roller mounted in an exposed edge of the cartridge moves tape past 
a read/write head in the drive. 
BACKGROUND OF THE INVENTION 
U.S. Pat. No. 4,863,114 to Moeller, et al shows a mini-cartridge in which 
1/4" magnetic tape stores computer data. The tape is moved between two 
reels in the cartridge by a driven roller. The driven roller moves the 
tape and also moves the reels through a belt arrangement. The driven 
roller is engaged by a drive roller in the drive when the cartridge is 
inserted into the drive. 
Magnetic tape drives for use with this type of cartridge are available from 
a number of sources. U.S. Pat. Nos. 3,526,371 to Blackie, et al; 3,924,823 
to Cohen, et al; 4,647,994 to Irwin, et al; and 4,984,111 to Rudi, are 
examples of drives utilizing this type of data cartridge. These drives are 
mounted in a cabinet and rack containing a personal computer and 
peripherals. These drives are generally available in a size which has a 
height of approximately 15/8 inches. In the drives shown in the foregoing 
patents, the drive roller is directly driven by the motor. In other 
versions, the drive roller may be driven by a belt. 
The present invention is an improvement upon the tape drives discussed 
above. 
SUMMARY OF THE INVENTION 
In accordance with the present invention, the driven roller in a magnetic 
tape cartridge is driven by an idler capstan that, in turn, is driven by a 
drive roller on the cartridge drive motor. 
The invention has an important advantage over prior tape drives in that the 
height of the drive is considerably smaller than in previous drives. The 
drive of the present invention fits within the one inch high opening that 
is common for disk drives for 31/2" floppy disks. 
The present invention also has the advantage that the speed of the tape is 
not affected by changes in the diameter of the resilient idler capstan 
because it transmits the tangential velocity of the motor roller. 
Therefore, the diameter of the idler capstan need not be tightly 
controlled. In both the direct drive and belt drive designs, the diameter 
of the resilient drive roller directly affects the speed of the cartridge 
and must be held to tight tolerances. In addition, in a belt driven 
design, the thickness of the belt needs to be tightly controlled. In the 
idler capstan drive of the present invention, only the diameter of the 
motor drive roller requires tight tolerances, and this is easily 
controlled because it is metal, not a difficult to control resilient 
material. 
Because the pre-load force of the motor is transmitted to the cartridge by 
the idler capstan, the bearings in the idler are very lightly loaded, 
allowing the use of a low cost bushing instead of the ball bearings 
required in a belt driven design. Furthermore, fewer components are 
required than in a belt driven design. 
Further in accordance with the invention, a mount for the magnetic head 
provides an azimuth adjustment for the head with respect to the 
translational motion of the tape. The mount is integrally molded with the 
drive frame and resiliently connected to the frame. 
Further in accordance with the invention, a metal bracket attached to the 
drive frame provides means for mounting the drive in the rack and cabinet 
normally provided for a personal computer and its peripherals. The bracket 
is flexible and protects the drive frame from mounting stresses which 
might otherwise damage the frame. The metal bracket also provides an 
electrical ground and shield for the electronics of the drive. 
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 
A magnetic tape cartridge 10 has a driven roller 12 in the cartridge for 
moving magnetic tape 14 past a read/write head 16 (FIG. 2) in the tape 
drive. The cartridge 10 is generally rectangular in shape and has two 
reels upon which the tape is wound and unwound. The driven roller 12 is in 
an exposed edge of the cartridge. 
In accordance with present invention, the drive roller 18 in the drive is 
engaged by an idler capstan 20. The drive roller 18 is directly driven by 
the motor 22. The drive roller 18 engages the idler capstan 20 to rotate 
it. Idler capstan 20 has a resilient periphery 24. When a cartridge is 
inserted into the drive, the driven roller 12 in the cartridge engages the 
resilient periphery 24 of the drive roller 18. The idler capstan 20 and 
the driven roller 12 are rotated by drive roller 18 to move the magnetic 
tape in the cartridge. Because of the use of the idler capstan 20, changes 
in the diameter of the idler capstan, caused by wear of the resilient 
periphery, do not affect the speed of the tape. The diameter of the idler 
capstan 20 need not be tightly controlled. 
In accordance with the present invention, the drive roller 18 is mounted on 
the motor 22. The idler capstan 20 is mounted on arm 51 which is pivoted 
at 28. Bracket 26 supports pivot 28. The motor 22 is also pivoted about 
28. The spring 30 biases the motor 22 and the idler capstan 20 toward the 
cartridge. When a cartridge is inserted into the drive, the driven roller 
12 presses against the idler capstan 20 to move the motor 22 and the arm 
51, and idler capstan 20, slightly against the bias provided by spring 30. 
This provides firm engagement between idler capstan 20 and driven roller 
12. Guide 63 constrains vertical movement of motor 22 as the motor moves 
slightly about pivot 28. 
The mounting of the idler capstan 20 and drive roller 18 on top of the 
motor 22, with the entire assembly being pivoted, is important to the low 
profile of the drive. In prior designs in which the driven roller in the 
cartridge is driven directly by the drive roller on the motor, more height 
is required to insert the cartridge over the motor. The present invention 
provides a significant height advantage in drives of this type. 
Magnetic read/write head 16 is mounted on a rail 31 for movement along the 
rail transverse to the longitudinal direction of the tape. A stepper motor 
32 drives a gear train 59 which rotates the screw jack 60 to move the 
magnetic head 16 in increments across the tracks of the magnetic tape. 
Further in accordance with the present invention, the read/write head 16, 
rail 31 and stepper motor 32 are on a mount 38, which is shown in FIG. 3. 
Mount 38 is integrally molded with the drive frame 42. Mount 38 is 
flexibly connected at 40 and 41 to the drive frame 42. The space 61 allows 
the mount 38 to move with respect to frame 42. As the mount 38 is moved 
with respect to frame 42, by rotating adjusting screw 52, the azimuth of 
the magnetic head with respect to the translational motion of the tape is 
adjusted. This provides an important accuracy adjustment for reading and 
writing on the tape. 
Frame 42 is made of plastic which is not a good conductive material and 
which can be warped if severely stressed during mounting. A flexible metal 
mounting bracket 44 is connected to the plastic frame 42. Metal bracket 44 
has six screw holes 46 (FIG. 2) and four screw holes 48 for mounting the 
drive in a cabinet having a rack for the personal computer and other 
peripherals. The metal bracket 44 provides a good electrical connection to 
the cabinet which the plastic frame 42 does not otherwise provide. The 
metal bracket is connected at 50 to the printed circuit board to provide a 
positive electrical ground for the circuit board. The mounting bracket is 
flexible so that it absorbs the stress which occurs during mounting in a 
rack having slightly non-standard dimensions. 
While a particular embodiment of the invention has been shown and 
described, various modifications of the invention are within the true 
spirit and scope of the invention. All such modifications are encompassed 
by the following claims.