Drive belt loading system

A drive belt loading system for automatically loading and unloading a drive belt onto a pulley of a removable device employs a conical transfer means for automatically transferring the drive belt to the pulley upon tensioning of the belt. The transfer means is located below the device pulley so that upon slackening of the belt, the belt is automatically unloaded by dropping back onto the transfer means to allow removal of the device. The system is applied to drive belt loading in a magnetic disk file employing a disk module with an external pulley.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The invention relates to drive belt loading systems and to magnetic disk 
drives employing such systems. 
2. Description of the Prior Art 
A drive belt loading system for use in a magnetic disk file is shown in 
FIGS. 2A and 2B of U.S. Pat. No. 3,786,454 to Lissner and Mulvany. In that 
patent a pair of spring biased idler arms are employed in a disk drive to 
splay apart a drive belt and enable the receipt of a data module pulley 
within the loop formed by the belt. A loading mechanism moves the data 
module so that its pulley contacts the belt and overcomes the action of 
the idler arms which are then pivoted inwardly. Loading motion of the 
module also moves a belt drive motor, mounted on a pivot plate, against a 
spring bias. A cam on the pivot plate strikes the idler arms and forces 
them to a position out of contact with the belt. Reversal of the above 
procedure unloads the belt and permits removal of the module. The Lissner 
and Mulvany arrangement requires both motion of the module and the drive 
motor to effect loading and is relatively complex. 
United Kingdom Pat. No. 593,780 shows an arrangement for coupling two 
horizontal shafts for co-rotation by means of a belt. The belt is placed 
on an idler pulley on one shaft and is manually shifted from a perch to a 
conical portion of a pulley fixed to a second shaft. Rotation of the shaft 
causes the belt to climb the conical portion of the second shaft pulley 
and at the same time to transfer from the first shaft idler pulley to an 
adjacent pulley fixed to the first shaft. Thus the two shafts are coupled 
for rotation together. However, this coupling is not automatic and neither 
shaft is part of a removable device. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide a new and simplified 
drive belt loading system for automatically loading and unloading a drive 
belt to a removable device. 
It is a further object of the invention to provide an automatic drive belt 
loading system employing tensioning and slackening of a drive belt 
together with gravity to effect loading and unloading of the belt. 
These and other objects of the invention are achieved in a drive belt 
loading system in which a belt is maintained in contact with a drive motor 
output shaft and, when unloaded, rests on a tapering transfer device 
located below the connecting shaft or pulley of a removable device which 
is to be driven. Means for tensioning the belt move it up the transfer 
device and transfer it to the connecting shaft or pulley of the removable 
device which is thereby coupled to be driven by the drive motor output 
shaft. When the same means are used to slacken the belt, it drops from the 
driven shaft or pulley back to the transfer means and allows removal of 
the removable device.

In FIG. 1A a crown drive pulley 2 is rigidly attached to a vertical shaft 4 
of an electrical motor 6. Drive pulley 2 has an integral flange 8 on its 
lower side adjacent to the motor 6. An endless drive belt 10 is supported 
by flange 8. 
A driven pulley 12 is rigidly attached to a vertical shaft 14 supported by 
suitable bearings (not shown). Located below, adjacent and concentric with 
driven pulley 12 is a conical frustum 16 on a circular base plate 18. 
Conical frustum 16 tapers towards driven pulley 12 and the diameter of its 
upper surface 20 is approximately equal to the diameter of driven pulley 
12. Conical frustum 16, shaft 14 and driven pulley 12 share a common 
vertical axis. Circular base plate 18 forms a ledge 22 around the base of 
conical frustum 16, and is fixed to a rigid support 24. 
Drive pulley 2 and driven pulley 12 are in the same horizontal plane. Drive 
belt 10 has its length chosen so that it has a slack fit around drive 
pulley 2 and may extend around conical frustum 16 to rest on ledge 22. In 
this inoperative position, if power were applied to electric motor 6 to 
rotate drive pulley 2, belt 10 might rotate, but no power would be applied 
to driven pulley 12. It may be noted that in the inoperative position as 
shown in FIG. 1A, belt 10 is held loosely around drive pulley 2 and 
conical frustum 16 by gravity. As pulleys 2 and 12 are in the same 
horizontal plane, belt 10 is not horizontal and slopes downwards from 
flange 8 to ledge 22. 
Electric motor 6 is pivotally mounted and may be moved in a direction 
indicated by arrow A to increase the distance between drive pulley 2 and 
drive pulley 12 whilst maintaining shaft 4 vertical. When electric motor 6 
is moved, tension is applied to belt 10 which slides upwards on the 
surface of conical frustum 16 towards driven pulley 12. When electric 
motor 6 is switched on and rotates, drive motion indicated by arrow D is 
applied to belt 10 which assists transfer of the belt from conical frustum 
16 to driven pulley 12 to rotate driven pulley 12 as shown in FIG. 1B. 
In this figure belt 10 is shown in a horizontal drive position and remains 
in this position due to the centripetal action of crown pulley 2. When it 
is desired to remove the drive from driven pulley 12, electric motor 6 is 
switched off and moved as indicated by arrow B. Tension is removed from 
belt 10 which slides down the surface of conical frustum 16 and takes up 
the inoperative position as shown in FIG. 1A. It should be noted that in 
this position, driven pulley 12 attached to shaft 14 may be removed as 
belt 10 is resting on the surface of conical frustum 16. 
Drive belt 10 is preferably a flat belt made of a plastics material which 
in an untensioned condition tends to form a circle. Conical frustum 16 may 
be of metal or of a plastics material and should have a smooth surface 
along which drive belt 10 may slide easily. 
FIG. 1B shows drive belt 10 tensioned in a horizontal drive position, with 
shafts 4 and 14 vertical. However, although it is essential that shafts 4 
and 14 should be parallel, there is no necessity for drive belt 10 to be 
horizontal when in the drive position. The belt drive arrangement may be 
used with drive belt 10 in a non-horizontal drive position provided that 
when tension is removed from drive belt 10 and motor 6 switched off, the 
belt 10 moves downwards under gravity to rest on ledge 8 or some other 
suitable support, and to rest on the surface of conical frustum 16 or an 
equivalent transfer device. Then when tension is applied again to belt 10 
and motor 6 switched on, belt 10 will return to the drive position as 
previously described. 
In FIGS. 1A. and 1B the belt transfer device is shown as conical frustum 
16, as a cone is probably the easiest suitable shape to fabricate. It may 
be noted that only a portion of the surface of conical frustum 16 remote 
from drive pulley 2 is contacted by drive belt 10 and thus only this 
surface portion actually needs to be provided. Therefore only 
approximately one half of conical frustum 16 is essential and the half 
designated by 17 in FIG. 1A is redundant and could be removed. 
Essentially the belt transfer device acts as a guide for belt 10 and must 
provide at least a surface on which drive belt 10 may be supported just 
before transferring to driven pulley 12, together with a surface tapering 
towards the curved surface to provide a rest position for drive belt 10. 
The surfaces need not be continuous and may be formed by an assembly of 
rods pointing towards driven pulley 12. 
Although in FIGS. 1A and 1B, electric motor 6 is movable to tension drive 
belt 10, this tensioning may be accomplished by other methods. For example 
drive belt 10 may be tensioned by a movable idler pulley or driven pulley 
12 and conical frustum 16 could be moved away from drive pulley 2. 
The belt transfer arrangement as described with reference to FIGS. 1A and 
1B has application in providing drive for magnetic disk files. A disk file 
in which a removable data module has an external drive pulley which is 
belt driven to rotate disks within the module is shown in the above 
referenced U.S. Pat. No. 3,786,454 (Lissner et al). 
Referring now to FIG. 2 which is a diagram illustrating an application of 
the invention to a magnetic disk file similar to that described in the 
Lissner et al patent. Whenever possible the same reference numerals for 
similar components are used as in FIGS. 1A and 1B. FIG. 2 shows an 
interchangeable disk module 30 in dotted outline with a carrying handle 32 
shown in position locked to base plate 38. Disk module 30 contains 
magnetic disks 34 attached to shaft 14 mounted for rotation on bearings 
36. The module also contains magnetic heads (not shown) for transducing 
data on the disks. A driven pulley 12 is attached to the lower end of 
shaft 14. A conical frustum 16 is mounted on base plate 38 below and 
concentric with driven pulley 12. 
Electric motor 6 is mounted on plate 40 which is mounted on base plate 38 
to pivot horizontally. Shaft 4 of electric motor 6 has a crown drive 
pulley 2 fixed to its upper end. A drive belt 10 is supported in position 
around drive pulley 2 by a support plate 42 attached to base plate 38. 
Drive belt 10 is shown in the inoperative position resting on conical 
frustum 16 as previously described with reference to FIG. 1A. 
Electric motor 6 is held in the inoperative position by pivotally attached 
rod 44 being held against cam 46 by spring 48. Cam 46 is rotated by the 
act of closing lid 50 as indicated schematically by arrow 52 which 
represents actuation as described in detail in the aforementioned Lissner 
et al patent. This action moves rod 44 to the left as indicated by arrow A 
to pivot plate 40 and move drive pulley 2 into the drive position. 
Alternatively electric motor 6 may be moved by an electromagnetic actuator 
operated by a microswitch when lid 50 is closed. When electric motor 6 is 
started, drive belt 10 will transfer to driven pulley 12 as previously 
described with reference to FIG. 1B. 
When it is required to remove disk pack 30, electric motor 6 is stopped, 
and lid 50 opened to rotate cam 46 and allow drive pulley 2 to move back 
to the inoperative position as indicated by arrow B. This places drive 
belt 10 in the inoperative position resting on conical frustum 16 below 
driven pulley 12. Thus disk module 30 may be removed and replaced by 
another disk module. 
The invention provides a simple belt loading and unloading arrangement 
which is particularly useful in applications where the driven pulley is in 
an inaccessible position. In most applications involving continuously 
running machinery it is usual and desirable for the drive arrangements to 
be permanently connected. However, there are some applications in which 
the drive needs to be disconnected from time to time and subsequently 
reconnected. Such applications include: 
(i) disk stores in which disk modules having an external drive pulley are 
connected in use to a belt drive in a drive unit; 
(ii) test equipment in which the apparatus to be tested is temporarily 
connected to a belt drive in the test equipment before being connected to 
a permanent drive in a using system: and 
(iii) an alternative to inertia clutch arrangements for driving large loads 
where the driving means is incapable of starting under load conditions. 
Belt slip during transfer of the moving belt from transfer device to 
driven pulley enables the driven pulley to be accelerated under relatively 
high load condition.