Information handling system for use with information containing storage discs

An information handling system for use with information containing storage discs, specifically optical discs, is disclosed herein. This system, which may be referred to as a jukebox, includes a combination drive and disc storage unit, a separate disc storage unit without a drive, and a storage disc transport unit. The combination drive and disc storage unit contains a drive assembly for writing information onto and retrieving it from the storage discs as well as shelves for individually storing specific ones of the discs. The separate disc storage unit includes only the shelves. While the storage disc transport unit contains an arrangement of robotic components for transporting specific storage discs between their storage shelves and the drive assembly pursuant to commands from an external source, specifically from a control computer forming part of the system and an outside host computer.

The present invention relates generally to information handling systems and 
more particular to a very specifically designed information handling 
system for use with information containing storage discs, for example, 
optical discs. 
Information handling systems for optical discs, video discs or information 
storage discs generally are known in the art. An example of one such 
system is illustrated in U.S. Pat. No. 4,271,489. Another such system is 
described in U.S. Pat. No. 4,608,679. In each of these cases, a group of 
storage discs are stored on individual shelves in a storage area and 
transported to and from one or more read/write players (drive assemblies) 
in a drive area by means of a movable carriage arrangement in response to 
external commands. Each of these types of systems and the system disclosed 
herein will at times herein be referred to as a jukebox for convenience. 
It is an object of the present invention to provide a jukebox, that is, an 
information handling system for use with information containing storage 
discs, which incorporates a number of improvements over the art. 
One particular object of the present invention is to provide a jukebox 
which is readily expandable by the user in an uncomplicated and economical 
way. 
As will be described in more detail hereinafter, the information handling 
system or jukebox disclosed herein utilizes a combination drive and disc 
storage unit and a storage disc transport unit and it may or may not 
include a third unit for disc storage only. The combination drive and disc 
storage unit includes a drive/disc support structure having a specific 
system coupling side, at least one drive assembly for writing information 
onto or retrieving information from the storage disc and a group of 
storage shelves for individually storing specific ones of the discs. Both 
the discs and the drive assembly are accessible from the coupling side of 
the drive/disc support structure. The storage disc transport unit includes 
its own transport support structure having at least one coupling side 
removably positionable in an operating position adjacent to and facing the 
coupling side of the drive and disc storage unit and means for 
transporting specific ones of the storage discs between any of the storage 
shelves and the drive assembly pursuant to commands from an external 
source. 
The overall system just described briefly above is expandable in a number 
of uncomplicated and economical ways. First, a unit devoted to disc 
storage alone can be added to the system without structurally changing 
either the combination drive and disc storage unit or the disc transport 
unit. Rather, this latter unit is already designed to include a second 
coupling side removably positionable in an operating position with the 
added unit for transporting storage discs between the drive assembly and 
any shelf in the system, again without structurally modifying any of the 
units and particularly without structurally modifying the transport unit. 
Another way to readily expand the system, especially if a separate storage 
unit is added, is to add one or more drive assemblies to the combination 
drive and disc storage unit in place of shelves. The system is designed so 
that this can be done without structurally changing the disc transport 
unit. Still another way to expand the overall system economically is to 
add one or more drive and disc storage units with or without additional 
driveless disc storage units without adding an additional transport unit. 
The latter can be readily mounted for movement between different ones of 
the other units and operably coupled thereto without having to be 
physically connected to these units. 
A second particular object of the present invention is to provide a jukebox 
in which individual information storage discs can be easily placed into 
and removed from the system without requiring deviations in the way in 
which its transport unit functions. 
As will be described in detail hereinafter, this last-mentioned object is 
accomplished by providing an entry/exit arrangement in the combination 
drive and disc storage unit which to the transport unit appears merely as 
another storage shelf from a mechanical movement standpoint. To this end, 
the entry/exit arrangement includes its own entry/exit storage shelf 
supported by the drive/disc support structure so that it is accessible 
from both the coupling side of that structure and a different external 
side. Most important, the entry/exit shelf is configured and positioned so 
that it appears merely as another storage shelf to the transport unit and 
is located between two storage shelves or a storage shelf and drive 
assembly or two drive assemblies. Once a storage disc to be placed into 
the system is inserted into the entry/exit shelf from its outer accessible 
side, the transport unit may retrieve it mechanically in exactly the same 
manner it retrieves a storage unit from another shelf, although it does so 
at a slow speed to protect internal components within the entry/exit 
shelf. 
Another feature of the entry/exit arrangement just described resides in its 
ability to prevent storage discs from inadvertently being placed in the 
system in the wrong way. Specifically, the arrangement disclosed herein 
includes mechanical means configured to cooperate with the design of the 
storage disc so that an individual storage disc can be placed into the 
entry/exit shelf from its external side in only one way, the right way. 
A third particular object of the present invention is to provide an 
uncomplicated and yet reliable storage disc transport unit and 
specifically one which takes care not to damage the storage discs being 
transported from point to point. 
As will be described in detail hereinafter, the specific transport unit 
disclosed herein and the other units utilize vertically extending 
structures. The transport unit utilizes a carriage assembly including a 
carriage and means for moving the carriage vertically within its own 
vertically extending transport support structure, means for moving the 
carriage vertically within the transport support structure, and at least 
one disc engaging and disengaging arm arrangement carried by the carriage 
and means also carried by the carriage for moving the arm arrangement 
horizontally across the carriage for transporting discs between the 
carriage and a storage shelf or drive assembly. 
In accordance with one feature of the transport unit, the carriage itself 
is moved vertically by means of vertically extending drive belts 
supporting opposite sides of the carriage. In this way, the carriage can 
more reliably be maintained in a desired horizontal plane than can be 
achieved by the typical drive screw means utilized heretofore. This 
particular drive belt arrangement also includes the added feature of 
ensuring that the carriage does not move vertically as its arm arrangement 
is taking a storage disc out of or moving into a storage shelf or drive 
assembly. Specifically, as this latter operation takes place, a mechanical 
brake prevents vertical movement and preferably at the same time the drive 
means used to provide vertical movement of the carriage is de-energized 
and/or de-coupled from the carriage. 
As the arm arrangement just recited is in the process of moving a 
particular storage disc out of or into a shelf or drive assembly, if it 
does so in an improper way, as will be described, the overall system is 
alerted and automatically goes into a safety mode. As will be seen, in 
some cases, attempts are made to correct the situation. However, as these 
attempts are made, those drive motors involved are operated in a torque 
mode rather than the normal acceleration mode. 
A fourth object of the present invention is to provide an uncomplicated but 
reliable way in which the arm arrangement forming part of the carriage 
assembly engages a storage disc for movement between the carriage and 
either a storage shelf or the drive assembly. As will be seen hereinafter, 
each of the storage discs, actually its cartridge housing, includes a 
front edge and a pair of cartridge housing features consisting of 
laterally outward protrusions or indentations. The arm arrangement 
includes a pair of disc engaging hooks, means for moving the hooks around 
the back of the protrusions or into the indentations (hereinafter merely 
referred to as protrusion) and bumper mechanisms for engaging the front 
face of the cartridge housing. In that way, the storage disc and its 
cartridge housing cannot move to any significant degree relative to the 
arm arrangement. 
With particular regard to the hooks just recited, in a preferred 
embodiment, each is designed to include a plurality of links pivotally 
connected to one another and movable between a storage disc engaging 
position and a disengaged position by means of a suitable drive mechanism, 
for example, an electrically actuated solenoid. Each hook is configured so 
that two of its links form a knee lock when the hook is moved into its 
disc engaging position and breaks out of this knee lock when the hook is 
moved back to its disengaging position. In that way, because of its knee 
lock, the hook maintains a strong hold on the storage disc without 
requiring the application of a large force by its associated solenoid or 
other such drive mechanism.

Turning now to the drawings, wherein like components are designated by like 
reference numerals throughout the various figures, attention is first 
directed to FIGS. 1A, 1B and 1C. FIG. 1A illustrates by means of block 
diagram an expandable type of information handling system which is 
designed in accordance with the present invention for use with information 
containing storage discs, one of which is shown in FIG. 1C within its own 
cartridge housing. The system is generally indicated by the reference 
numeral 10 and the overall disc assembly, that is, the disc and its 
cartridge housing, is generally indicated at 12. The disc itself is shown 
by dotted lines at 14 and the cartridge housing is shown at 16. The disc 
itself is connected to a frame having an end tab 18 which extends out of 
the housing so that the disc can be moved into and out of its housing. 
The disc itself may be any suitable type containing information that can be 
read onto or retrieved from it by a cooperating player or drive assembly. 
Neither the disc itself nor the drive assembly per se forms part of the 
present invention. Both are readily providable components in the art and 
hence will not be described herein. In an actual working embodiment of the 
present invention, the disc itself can be and preferably is an optical 
disc which contains digital data and the drive assembly may be for example 
an optical disc read station. However, even this actual working embodiment 
can be used with other types of storage media such as, for example, tapes. 
For purposes of the description to follow, it will be assumed that the 
entire disc assembly (the disc and its housing) is transported back and 
forth between its storage point and the player (drive assembly) and that 
the player, upon receipt of the assembly, automatically gains access to 
the disc itself either by removing it from its cartridge housing or 
otherwise. However, unless pertinent to the description to follow, 
reference will be made only to the disc assembly rather than the disc 
alone or the cartridge housing by itself. 
Turning to FIG. 1A in conjunction with FIG. 1B, the overall system 10 is 
shown including a combination drive and disc storage unit 20, a disc 
storage unit without a drive, that is, a driveless disc storage unit 22, 
and a storage disc transport unit 24. All three are linked in a readily 
providable, conventional way to control computer 26. The control computer 
itself does not per se form part of the present invention and can be 
readily provided along with operating software by those with ordinary 
skill in the computer and computer software design art in view of the 
teachings herein. In other words, computer 26 and its operating software 
can be readily provided to operate overall system 10 in the manner to be 
described utilizing the structural components of the system which will 
also be described in view of the detailed description to follow. Moreover, 
it is important to note that control computer 26 is designed to command 
transport unit 24 so as to transport disc assemblies between various 
locations in the system to be described below. However, the particular 
disc assembly or assemblies to be transported and where they are 
transported is determined by a host computer (not shown) which interfaces 
with computer 26 and which gives these commands to that computer. 
Referring specifically to FIG. 1B, the drive and disc storage unit 20 is 
shown including the following components broadly. First it includes a 
vertically extending drive/disc support structure 28 having a plurality of 
vertically extending sides including a specific system coupling side 30. 
One or more drive assemblies 32 are supported by structure 28 and each has 
means (not shown) for writing information onto or retrieving information 
from a particular storage disc 14 (FIG. 1C) pursuant to commands from the 
host computer referred to above when the particular disc is in an 
operating position defined by the drive assembly. As indicated above, 
these drive assemblies are known in the art and hence will not be further 
described herein. It suffices to say that each is supported by drive/disc 
support structure 28 at a particular point along its vertical extent such 
that the operating position of the assembly is accessible from the 
coupling side 30 of the support structure. 
In addition to the general components thus far described, the drive and 
disc storage unit 20 includes a plurality of readily removable storage 
shelves 34 for individually storing specific ones of the storage disc 
assemblies and an entry/exit arrangement generally indicated at 36 in FIG. 
1A for placing a specific storage disc into and removing it from overall 
system 10. The storage shelves are supported by the drive/disc support 
structure in vertically spaced positions above and/or below drive 
assemblies 32 so as to be accessible from the coupling side 30 of 
structure 28. As stated above, they are readily removable and thereby 
groups thereof can be easily replaced with a larger shelf for containing 
an additional drive assembly. At the same time, as will be best described 
in conjunction with FIG. 2 hereinafter, entry/exit arrangement 36 includes 
its own entry/exit storage shelf 38 (see FIG. 2) which is accessible both 
from coupling side 30 of structure 28 and from an opposite external side 
40. 
Still referring to FIG. 1B, the driveless disc storage unit 22 also 
includes a vertically extending support structure 42 having its own 
vertically extending sides including a specific coupling side 44. A 
plurality of storage shelves 46 for containing individually specific disc 
assemblies 12 also form part of unit 22 in vertically spaced positions so 
as to be accessible from coupling side 44. Note that unit 22 does not 
include a drive assembly 32 and, as will be seen hereinafter, it does not 
actually have to form part of overall system 10. Rather, it can be added 
to the system at a subsequent time as a means of expanding it when that 
becomes desirable. However, for purposes of describing the overall system, 
unit 22 will be included. 
Referring now to the storage disc transport unit 24, this unit is shown in 
FIG. 1B including its own vertically extending transport support structure 
48 having a number of vertically extending sides including opposite system 
coupling sides 50 and 52 which, as will be seen hereinafter, are removably 
positionable in operating positions adjacent to and facing the coupling 
sides 30 and 44, respectively, of units 20 and 22 without having to be 
mechanically connected to either one. The storage disc transport unit also 
includes an overall apparatus which is generally indicated at 54 in FIG. 
1B for transporting specific ones of the disc assemblies 12 between any of 
the storage shelves 34 and 46, the entry/exit shelf 38 and drive 
assemblies 32 pursuant to commands from computer 26 which, in turn, 
receives its instructions from the host computer, as stated previously. As 
will be described in detail hereinafter, apparatus 54 includes a carriage 
assembly 56 including a carriage 58, a drive arrangement generally 
indicated at 60 in FIG. 1B for moving the carriage vertically within 
transport support structure 48, two disc engaging and disengaging arm 
arrangements 62 and 64 carried by carriage 58, and drive mechanisms 66 and 
68 (see FIG. 18) for moving the arm arrangements horizontally across the 
carriage. 
Referring specifically to FIG. 2, overall system 10 is shown 
diagrammatically in an operating position, that is, with the coupling 
sides 50 and 52 of transport unit 24 in their respective operating 
positions adjacent to and facing the coupling sides 30 and 44 of units 20 
and 22, respectively. Note that the storage shelves 34 and 46 have been 
exaggerated in size (with some obviously not shown) and that all of the 
shelves including those containing drive assemblies 32 have been given 
position numbers 1-24 for purposes of description. In the diagrammatic 
depiction of FIG. 2, some of the storage shelves include disc assemblies 
12, specifically shelves 2, 14, 16 and 18, as does the entry/exit shelf 38 
which is in position 8. In this regard, for reasons which will become 
apparent hereinafter, when a given disc assembly 12 is properly stored in 
or on its particular shelf, a front end segment thereof extends out beyond 
the coupling side of its unit, coupling side 30 in the case of unit 20 and 
coupling side 44 in the case of unit 22. 
Still referring to FIG. 2, carriage assembly 56 is also depicted quite 
diagrammatically and, as shown in this figure, includes only the carriage 
56 and arm arrangements 62 and 64 for purposes of the present discussion. 
The entire carriage assembly and arm arrangements are moved as a single 
entity by drive arrangement 60 to be described hereinafter, as indicated 
by vertical arrows 70. Note that as it does so, opposite edges of the 
carriage move past the front spaces of shelves 34, 46, entry/exit shelf 38 
and drive assemblies 32. At the same time, each of the arm arrangements 62 
and 64 is movable horizontally from one end of the carriage to the other 
end by means of drive mechanisms 66 and 68 to be described hereinafter in 
conjunction with FIG. 18, as indicated by two-way arrows 72. Moreover, as 
will also be described in more detail hereinafter in conjunction with 
FIGS. 14, 15 and 18, a section of carriage 58 is capable of rotating 
180.degree. back and forth about a center shaft 74 (without rotating arm 
arrangements 64), by means of a drive arrangement (see FIGS. 18-22) to be 
described hereinafter. 
With overall system 10 described thus far, attention is now directed to the 
way in which it operates without regard to the details of its structural 
components. Still referring to FIG. 2, system 10 is initially placed into 
operation first by ensuring that the three units 20, 22 and 24 are at 
their proper operating positions with respect to one another. In this 
regard, as will be seen hereinafter in conjunction with the description of 
FIGS. 3 and 4, the three units do not have to be physically connected or 
even touching one another. The carriage assembly 56 and units 20 and 22 
include cooperating optical sensing arrangements which ensure the units 
are in the proper operating positions and also tells the computer exactly 
where each shelf position is with respect to the carriage assembly at any 
point along its vertical path of movement and whether the shelf is a 
storage shelf, an entry/exit shelf or at drive assembly location. 
Therefore, the carriage assembly is initially caused to move through its 
entire vertical extent from, for example, its top end to its bottom end. 
As it does so, it senses the various positions of shelves 1-24 to 
determine first if they are in acceptable locations (that is, operatively 
coupled properly) which is determined by the fact that the optical sensing 
arrangements function properly at all and exactly where and what each is 
on the vertical path. This information is delivered to computer 26 through 
a flexible lead bus 80 illustrated in FIG. 1B. In this regard, the drive 
arrangement 60 for moving carriage assembly 56 vertically includes an 
electric drive motor 82 (see FIGS. 1B and 13) having an encoder 
incorporated therein and also a servo-feedback circuitry responsive to the 
acceleration/deceleration curve associated with the carriage as it moves 
between its extreme upper end and its extreme lower end. In that way, as 
the carriage moves vertically, the computer through the encoder can keep 
track of where the carriage is comparing actual position to that 
calculated by the computer based on the acceleration/deceleration curve 
associated with the carriage. If there is too large of a discrepancy 
between actual and calculated position, the computer includes software to 
cause the carriage assembly to recalibrate its position along its vertical 
extent. To this end, the carriage also senses when it has reached the 
extreme top end of its movement and its extreme bottom end by sensing when 
the carriage and therefore the encoder have stopped at either end. 
In addition to assuring that the three units 20, 22 and 24 are operatively 
positioned correctly and calibrating the vertical extent of the carriage 
assembly, the horizontal movement of each arm arrangement must be 
calibrated and input into computer 26. This is accomplished in part by 
means of optical sensors and by means of mechanical stops as will be 
described hereinafter in conjunction with FIG. 5. For the moment, it 
suffices to say that each actuator arm is first moved horizontally to one 
end of carriage 58 and then to the opposite end. At each end of the 
carriage, it senses the point at which it is physically caused to stop 
(its end edge) then moves back a small distance to a photosensing point 
(its alignment point). 
The drive mechanisms 66 and 68 for arm arrangement at 62 and 64 include 
their own drive motors 84 and 86, respectively (see FIG. 18), which like 
motor 82 have their own encoder and similar servo-feedback circuits. The 
computer 26 monitors where each arm arrangement is via the associated 
encoder of each motor 84 and 86 while comparing actual position to that 
calculated based on the acceleration/deceleration curve associated with 
the arm arrangement. Thus, when, for example, arm arrangement 62 reaches 
its far left end stop on carriage 58 (as viewed in FIG. 2), this is fed 
into the computer by the encoder as, for example, counter point 0000. When 
the arm arrangement moves back a small distance to its alignment point, 
the amount of distance (in counts) is fed into the computer by means of 
the encoder, telling the computer exactly where the left end alignment 
point is. This is repeated for the right end of the carriage and for both 
ends with respect to arm arrangement 64. 
During subsequent operation of the overall system, the computer through the 
encoder of each motor 84 and 86 determines where its specific arm 
arrangement is while comparing that actual position to that calculated 
based on the acceleration/deceleration curve associated with the arm 
arrangement. In order to ensure that there is not a significant disparity 
between these two positions, that is, where the computer thinks the arm 
arrangements are, (which is the calculated position), and where they 
actually are, (which is the encoder position), each time an arm 
arrangement has reason to be in a position near one end of the carriage it 
automatically realigns itself at its alignment point. In this regard, 
these alignment points are specifically designed into the overall system 
so as to be located at or near points where the arm arrangements always 
must go, specifically, to points where they actually pick up or drop off 
disc assemblies. 
The reason it is critical that the computer know exactly where the carriage 
is at any point along its vertical extent and that it know where each arm 
arrangement is during its horizontal movement is that the computer 
operates the arm arrangements in a manner to be described hereinafter such 
that each is able to transport particular disc assemblies between storage 
shelves 34 and 46, entry/exit shelf 38 and drive assemblies 32. To this 
end, when, for example, computer 26 commands the carriage assembly to 
transport disc 12 from shelf position 2 and deliver it to the drive 
assembly in position 6, the carriage assembly moves to position 2 as shown 
in FIG. 2 and, for example, the actuator arm 62 moves through a series of 
end positions to be described hereinafter in conjunction with FIGS. 6-8 
for engaging the disc assembly in position 2. One of these end positions 
corresponds to an alignment position, at which time the arm arrangement 
can recalibrate itself. At the same time, it includes an arrangement of 
hooks and bumpers to be described in conjunction with FIG. 5 for engaging 
the front face of cartridge assembly in shelf position 2. 
Thereafter, arm arrangement 62 moves back away from that shelf 2 so as to 
pull the disc assembly onto carriage 58. In this regard, it can be seen 
from FIG. 2 that the carriage assembly is capable of supporting two such 
cartridge assemblies, one movable by arrangement 62 and the other movable 
by arrangement 64. Once the disc assembly 62 is properly supported on 
carriage 58, either that disc assembly or the other one on the carriage 
can be transported to another shelf or to a drive assembly by moving the 
carriage assembly downward or upward. At that time, the hook and bumper 
arrangements of the appropriate actuator can engage its associated 
cartridge assembly and move into the designated shelf or drive assembly. 
Before a cartridge assembly is removed from the carriage 58 it may be 
necessary to rotate the particular disc assembly before it is either 
stored away or more specifically because it is to be inserted into a drive 
assembly with a particular side of the disc facing upward. To this end, a 
section 130 of the carriage (see FIGS. 14 and 18) can be rotated in a 
manner described briefly above and more specifically in the manner to be 
described in detail hereinafter. In this regard, it should be noted that 
the carriage assembly needs a certain amount of clearance at its top end 
and a certain amount of clearance at its bottom end to perform this 
rotation function. Computer 26 is designed to allow the carriage to rotate 
only if it is a predetermined distance below its top end and a 
predetermined distance above its bottom end. 
Still referring to FIG. 2, it should be noted that as the carriage assembly 
56 moves vertically through drive/disc support structure 42, an entire 
vertical space is present between the top end of the structure and its 
bottom end on either side of the carriage assembly between the latter and 
the front faces of the disc assemblies stored in units 20 and 22. These 
vertical alignment corridors are supposed to be present if the disc 
assemblies are properly located in units 20 and 22 and the carriage 
assembly is properly positioned for vertical movement which means that the 
arm arrangement 62 and 64 are maintained within the confines of carriage 
58. Only under these conditions is it desirable to move the carriage 
assembly vertically. Therefore, unit 24 includes mechanisms to detect 
across the vertical extent of each corridor. Specifically, as shown in 
FIG. 2, phototransmitters 80 are mounted to the bottom end of support 
structure 42 at the appropriate locations and cooperating receivers 
(detectors) 82 are located at the top end of the structure in direct 
alignment with transmitters 80. This arrangement produces a pair of light 
beams 84 on either side of the carriage assembly. Should either of these 
light beams be interrupted by an obstacle in its path, for example, an 
incorrectly positioned disc assembly or should arm arrangement 62 or 64 be 
inadvertently located .beyond its carriage 58, this information will be 
given to computer 26 which will prevent the carriage assembly from moving 
vertically. As will be seen hereinafter in conjunction with FIGS. 9-12, 
this detection arrangement is also used to determine whether a disc 
assembly is properly removed from or stored into shelves 34, 38 and 46 and 
players 32. 
Speaking of shelves, as indicated previously, drive/disc support structure 
28 includes an entry/exit shelf 38 which is accessible from both the 
coupling side of the structure and an opposite external side. As shown in 
FIG. 2, the entry/exit slot includes a mechanism, for example the motor 
and belt arrangement generally indicated at 86 within shelf 38 for moving 
a tray 88 between a pickup position accessible from side 40 of support 
structure 28, as illustrated in dotted lines, and a storage position 
accessible from coupling side 30, as indicated by solid lines. This tray 
carries a disc assembly which is inserted into the system through the 
external side of unit 20 and moves the disc assembly to its internal 
storage position illustrated in FIG. 2. With the disc assembly in this 
latter position, it is so positioned to appear like any other disc 
assembly stored on a storage shelf 34 or 46. In other words, the carriage 
assembly 56 will pick up the disc assembly from and deliver it to 
entry/exit shelf 38 in the same mechanical way as it does so with regard 
to any other shelf. In this way, placing a disc assembly into or removing 
it from system 10 does not interrupt or change the normal mechanical 
operation of carriage assembly 56. However, as will be seen below in 
connection with FIGS. 3 and 4, a disc assembly may be picked up from and 
delivered to the entry/exit shelf or the drive assemblies at different 
rates of speed, for example slower speeds, than it is picked up and 
delivered to a storage shelf. This, for example, helps ensure that the 
disc assembly does not inadvertently damage any components within the 
entry/exit shelf or a drive assembly. 
Still referring to entry/exit shelf 38, as indicated previously this shelf 
is configured to allow a disc assembly to be placed therein in the right 
way only. To this end, an actuating arm 89 (see FIG. 2) carrying a detent 
89A thereon is spring-loaded (by means not shown) within shelf 38 for 
movement between a biased disc blocking position and a retracted position. 
With the actuating arm in its biased blocking position, if a disc assembly 
is placed in shelf 38 incorrectly, an opened edge 16A of its housing 16 
(see FIG. 16) is engaged by detent 89A to prevent the assembly from 
entering. If the disc assembly is inserted correctly, its closed end 16B 
pushes the actuating arm out of the way (to its retracted position) 
without engaging the detent. 
Turning now to FIGS. 3 and 4, attention is directed to the specific way in 
which carriage assembly 56 calibrates its vertical movement and determines 
the location of various positions 1-24 of units 20 and 22. As illustrated 
in FIGS. 3 and 4, each of the support structures 28 and 42 forming part of 
units 20 and 22 include in plates 90 mounted on the edges of coupling 
sides 30 and 44. As best seen in FIG. 4, each of these vertical plates is 
positioned near a corner of its support structure beyond the edges of 
those disc assemblies in the shelves. As best seen in FIG. 3, each plate 
90 includes a relief 92 which is precisely located with respect to an 
associated shelf or drive assembly. This is possible since each plate is 
physically connected to an associated support structure 28, 42. In this 
regard, it should be noted that whether a storage shelf in unit 20 is 
provided for storing a disc assembly, as for example in the case of 
position 2, or a drive assembly, as in the case of position 7, the disc 
assembly is delivered to or picked up from the same relative position with 
respect to relief 92. In this way, any of shelf positions can be utilized 
to receive a drive assembly and either of the drive assembly shelves shown 
can be used to support the disc assembly. 
Still referring to FIGS. 3 and 4, carriage assembly 56 is shown including 
photosensing devices 94 mounted to opposite sides of its frame. Each 
device which is readily providable includes a phototransmitting side 94A 
and a photoreceiving side 94B with a light beam (not shown) therebetween. 
Each device is positioned so that the solid part of cooperating plate 
member 90, between reliefs 92, will break the beam of a cooperating device 
while the relief will not. Thus, as the carriage assembly moves through 
its vertical extent, plate members 90 and devices 94 cooperate to sense 
the precise position of the carriage assembly. 
Carriage assembly 56 also carries a third photosensing device 95 which may 
be identical to devices 94 and unit 20 carries individual flags (plates) 
97A and 97B adjacent those shelves having drive assemblies (97A) and the 
entry/exit shelf (97B). Device 95 cooperates with these flags in the same 
manner as devices 94 cooperate with plate 90 to distinguish the drive 
assembly and entry/exit shelves from the storage shelves. With this 
information, the computer 26 operates arm arrangements 62 and 64 at a 
slower speed when transporting a disc assembly to and from the drive 
assemblies and entry/exit shelf than to and from a storage shelf. 
Moreover, the flag 97A associated with a drive assembly can vary in height 
depending on the type of drive assembly used to vary the speed in 
different ways or otherwise make computer 26 aware of the particular 
device assembly being used. In this regard, the flag 97A is easily 
removable and easily engagable into different shelf positions for 
converting a storage shelf to a drive assembly shelf. 
There may be a situation where unit 24 moves horizontally relative to units 
20 and 22, as will be discussed hereinafter in conjunction with FIG. 16 as 
an example. Under these circumstances, a different type of optical sensing 
arrangement may be used instead of devices 94, 95 and plates 90 and flags 
97A,B. FIG. 4A illustrates such an arrangement which includes a strip 99A 
of vertically spaced reflective surfaces 99B which would replace the 
plates 90 and reliefs 92. Individual reflective surfaces could replace 
flags 97A and 97B. A combination optical transmitter/receiver 99C would 
replace each device 94, 95. A beam of light 99D is directed to strip 99A 
and caused to reflect off of surfaces 99B as each device 99C moves with 
carriage assembly 56 and is reflected back to the device. The reflective 
strips can be positioned to correspond with the positions of reliefs 92 
thus operating in the same way. The reflective strips corresponding to 
flags 97A, 97B can vary in height just as the flags do. The advantage to 
this approach is that units 20, 22 and 24 can move horizontally (from side 
to side) without having to move away from one another as would be the case 
with plates 90, flags 97 and devices 94 and 95. 
Referring to FIG. 5, attention is now directed to the way in which arm 
arrangement 62 calibrates its horizontal movement 72 on carriage 58. Both 
the arm arrangement 62 and the carriage 58 have been illustrated 
diagrammatically in FIG. 5. For an actual working embodiment of these 
components, reference is made to FIGS. 17-22. Arm arrangement 62 is shown 
in FIG. 5 including a cross arm 96 having opposite front faces 98 and 100 
and sides 102. The cross arm 96 moves on carriage 58 in the manner 
described previously and carries with it an end plate 104. At the same 
time, a photosensing device 106 corresponding to the previously described 
devices 94 is mounted near each end of carriage 58. One such device is 
shown in FIG. 5. The other such device is mounted on the other end of the 
carriage. Each device is mounted inward a short distance from a mechanical 
stop 108 which prevents cross arm 96 from moving beyond the carriage. As 
the cross arm moves to its stop 108 end plate 104 moves through and past 
device 106. As indicated above, in order to calibrate the horizontal 
movement of the cross arm (actually the overall arm arrangement), it first 
moves to its stop position and then goes back to its alignment position. 
As shown in FIG. 5, this alignment position is where the end plate 104 
first breaks the optical beam forming part of device 106. As just stated, 
a similar device is located at the other end of the carriage along with a 
cooperating mechanical stop. Moreover, a similar pair of stops and 
cooperating optical sensing devices are mounted on the underside of 
carriage 58 for use with arm arrangement 64 which includes a corresponding 
cross arm and end plate. 
As indicated previously, each of the arm arrangements 62 and 64 serves to 
engage a disc assembly for transporting it onto and off of the carriage. 
Turning to FIGS. 6-8 in conjunction with FIG. 1C and FIG. 5, attention is 
directed to the way in which this is accomplished. First, it is important 
to note that the cartridge housing 16 of the disc assembly 12 includes 
laterally outwardly extending protrusions 110 on opposite sides of the 
cartridge housing at its front end, as illustrated in FIG. 1C. Similar 
protrusions 110 are on opposite sides of end tab 18. In FIG. 1D a modified 
cartridge housing 16' is shown with indentations 110' so as to 
functionally provide corresponding protrusions 110'A. For purposes herein, 
only the protrusions 110 will be referred to, it being understood that 
they could be functionally provided by indentations such as indentations 
110'. 
As illustrated in FIG. 5, the front face 98 of cross arm 96 carries with it 
a pair of laterally spaced, horizontally aligned hook members 112 and 
adjacent laterally spaced, horizontally aligned bumper members 114. The 
bumper members are mounted for simultaneous movement between raised, 
non-actuated positions shown in FIG. 5 and lowered, actuating positions, 
best seen in FIG. 7. In a similar manner, the hook members 112 are mounted 
for simultaneous movement between raised non-actuating positions shown in 
FIGS. 5 and 7 and lowered, actuating or disc engaging positions shown in 
FIG. 8. While not shown in FIG. 5, an identical arrangement of bumper 
members and hook members are located on the opposite face 100 of cross arm 
96. Moreover, as also will be described hereinafter in conjunction with 
FIG. 23, a single drive arrangement is provided for simultaneously moving 
all of the bumper members on cross arm member 96 and two drive 
arrangements are provided for moving the two pairs of hook members. 
Referring particularly to FIGS. 6-8, attention is now directed to the way 
in which the cross arm 96 actually engages a cooperating disc assembly for 
movement onto and off of carriage 58. As a first step, the carriage itself 
must be moved to a vertical position in alignment with the particular disc 
assembly in question. In FIG. 2, the carriage assembly is positioned next 
to position 2. Once that is done, the arm arrangement is moved 
horizontally to a predetermined first position close to but spaced from 
the disc assembly in shelf position 2. This might be for example its 
alignment position determined by device 106 or another position spaced 
inward from stop 108. During this movement, the bumper and hook members 
are in their unactuated positions. The cross arm 96 is stopped in the 
first position at which time the bumper members are actuated, as shown in 
FIG. 7. The cross arm is then moved in incremental distance forward so 
that the bumper members engage the front face of cartridge housing 16. At 
that time, the hook members 112 are actuated, thereby moving downward, 
rotating 90.degree., as illustrated in FIG. 8, so that they extend around 
protrusions 110. In this manner, the cartridge housing is locked into 
engagement with the hook members and the bumpers so as now to be able to 
move horizontally. Once this takes place, the cross arm can be moved 
horizontally rearward so as to pull the disc assembly onto carriage 558. 
Thereafter, the hook members can be deactuated in order to release the 
disc assembly and the cross arm can be moved an incremental distance 
further so that the bumper members disengage the disc assembly and can 
thereby be deactuated. This places the disc assembly on carriage 58 free 
of arm arrangement 62. 
The description immediately above was for one side of cross arm 96. The 
hook and bumper members on the other side can be operated in a similar 
manner for engaging a disc assembly on that side. Moreover, the cross arm 
forming part of arm arrangement 64 includes corresponding hook and bumper 
members. These various hook and bumper members are operated through 
commands from computer 26 in order to transport disc assemblies between 
various storage shelves, the entry/exit shelf and drive assemblies. 
Further, while they have been shown diagrammatically in FIGS. 5-8, they 
are shown more realistically in FIGS. 17-23. 
Referring now to FIGS. 9-12, attention is directed to the way in which 
overall system 10 ensures that a given disc assembly is properly moved 
between a storage shelf or drive assembly and carriage 58. At this point, 
it should be recalled that the vertical corridors defined by light beams 4 
(FIG. 2) are normally clear if there are no unintended obstructions and so 
long as a disc assembly is not being moved between a shelf and the 
carriage. When a disc assembly is moved between a shelf and the carriage, 
system 10 is designed to operate the carriage assembly so that this is 
supposed to take a specific amount of time known by the computer. FIG. 9 
diagrammatically illustrates in exaggerated manner the point in time when 
cooperating hook members 112 are in their actuated positions ready to pull 
the cooperating disc assembly from its shelf onto the carriage. For 
purposes of clarity, the bumper members have not been shown but they would 
be in their actuated positions also. Moreover, it should be noted that at 
this very point in time, beam 4 is free to move between the disc assembly 
and carriage assembly, as shown in FIG. 9. However, as arm arrangement 62 
moves horizontally to the right (as viewed in FIG. 9) pulling out the disc 
assembly, the latter starts to block beam 4, as shown in FIG. 10. Under 
normal intended conditions, this continues for a predetermined period of 
time which can be determined by the computer since the length of the disc 
assembly is fixed and since the speed of its movement is known. Thus, so 
long as the beam 4 is blocked only for that period of time, the computer 
will know that the disc assembly has been successfully moved onto the 
carriage. This is also true where the disc assembly is moved off of the 
carriage and into a shelf (or drive assembly). In this regard, it should 
be recalled that the disc assembly moves into and out of a storage shelf 
at a different speed than it moves between a drive assembly and entry/exit 
shelf. Computer 26 can compensate for this difference. 
There are two distinct problems that may occur as a disc assembly is moved 
between its shelf and the carriage assembly. First, the cartridge housing 
and the disc (including its frame) may partially separate from one 
another, as illustrated in FIG. 11. If this occurs, the length of the 
overall disc assembly as it moves between the shelf and carriage assembly 
is longer than it should be. Thus, the light beam 4 is blocked for a 
longer period of time which alerts the computer to this situation. The 
second possibility is that only the cartridge housing is pulled off the 
shelf (or out of the drive assembly), leaving the disc and frame in place. 
Under this circumstance, only the cartridge housing blocks beam 4 which 
means that the beam is blocked for a shorter period of time than expected. 
Thus, the computer is alerted to this situation. 
In the actual operation of overall system 10, if either of the unintended 
situations described immediately above occurs, the computer commands the 
carriage assembly to attempt to retrieve the disc itself (in the second 
case) or commands it to move back into and out of its disc assembly 
engaging position (in the first case) in hopes of bringing the disc and 
its cartridge housing back together. It will attempt to do this at least 
once or several times in a preferred operating embodiment. However, as it 
does so, the computer will order the drive motor for moving the particular 
cross arm in question at a slower speed each and preferably the motor will 
be driven in a torque mode rather than an acceleration mode. In this way, 
should it be even slightly difficult to correct the situation, the motors 
will shut down so as prevent the carriage assembly from inadvertently 
damaging the disc assembly. Since the technique of utilizing an electric 
motor in both its acceleration and torque mode is not per se new, the 
description of how this is accomplished will not be provided herein. The 
present invention resides in the utilization by system 10 of this 
technique for protecting its equipment, not in the technique itself. 
Turning now to FIG. 13, attention is directed to the way in which overall 
carriage assembly 56 is moved vertically through transport support 
structure 48. For purposes of this description, the carriage assembly has 
been shown in FIG. 13 only diagrammatically as a plate member. As 
indicated previously, the carriage assembly is moved vertically by means 
of drive arrangement 60 including electric drive motor 82. As shown in 
FIG. 13, drive arrangement 60 includes a pair of endless drive belts 120 
connected at their upper ends to ends of a freewheeling shaft (not shown) 
and at their bottom ends to a drive shaft 122 which is shown in FIG. 13. 
The drive motor 82 is coupled to drive shaft 122 through a belt assembly 
124 for driving the shaft in one direction or the other. The carriage 
assembly 56 is connected to aligned horizontal points on one side of each 
drive belt 120 by suitable fastening lugs generally indicated at 126. At 
the same time, support structure 48 includes guides 127 (see FIG. 17) 
cooperating with the carriage assembly to ensure that the assembly remains 
horizontally aligned. As the drive belts 120 are driven by motor 82, this 
causes the connecting lugs 126 to move vertically, thereby pulling the 
carriage assembly with it. The fact that the carriage assembly is 
supported at two horizontally aligned points as it moves vertically, helps 
ensure that the carriage assembly remains horizontally aligned during its 
movement. 
As a safety feature in the overall operation of system 10, any time that an 
arm arrangement 62 or 64 is actually delivering or picking up a disc 
assembly in the manner described above, an electrically operated brake 128 
(which i in its braking mode when not electrically energized) forming part 
of drive arrangement 60 is deenergized for braking drive shaft 122 in 
order to ensure that the drive belts are not inadvertently moved during 
those times. To further ensure the drive belts do not move, will 
disconnect the power to the motor as well as the brake which, as stated 
above, causes the brake to engage. In addition, suitable switch means are 
provided for automatically shunting motor 82 in order to lock its drive 
shaft. Thus, there are several features which ensure that the carriage 
assembly does not move vertically as it is picking up and delivering a 
disc assembly. Moreover, so as not to place a large load on brake 128, the 
side of each endless belt includes a counterweight 129. 
As indicated previously, carriage assembly 56 is capable of flipping each 
disc assembly or assemblies supported on its carriage in order to rotate 
them 180.degree.. FIGS. 14 and 15 illustrate this. In both figures, the 
section of carriage 58 is shown diagrammatically at 130. That section is 
shown supporting a single disc assembly 12, although the overall carriage 
assembly is capable of supporting two such assemblies. Note from FIGS. 14 
and 15 that carriage section 130 is supported by the previously recited 
center shaft 74 for rotation about the axis of the latter in the manner 
described previously in conjunction with FIG. 2. In order to ensure that 
the disc assembly remains properly supported to the carriage section, the 
carriage includes spring-biased bearings 132 which engage in cooperating 
detents 134 in the sides of cartridge housing 16 (or corresponding detents 
134' in housing 16') (see FIGS. 1C and 1D). Two such arrangements are 
shown in FIG. 15. While this may suffice, it is possible to include 
additional such arrangements to ensure that the disc assembly remains in 
place. At the same time, the disc assembly must be readily removable from 
the carriage by means of cooperating arm arrangement 62 or 64 in the 
manner described above. 
With the exception of certain details to be described hereinafter, the 
foregoing has been the description of overall system 10 including both a 
drive and disc storage unit 20 and a driveless disc storage unit 22 along 
with a storage disc transport unit 24. As indicated previously, the 
overall system could include only the units 20 and 24 without the 
driveless disc storage unit 22. Under such circumstances, unit 24 would 
operate in the same manner described above. However, it would only act to 
transport disc assemblies on one side of its support structure. On the 
other hand, the system could be expanded to include more units 20 and more 
units 22 sharing a common transport unit 24. This is illustrated in FIG. 
16 which shows two transport units 24 on cooperating track assemblies 140 
for movement along straight lines paths. On either side of the path of 
each unit 24 are a series of units 20 and 22 in the same relationship 
illustrated in FIG. 1B. In the expanded system illustrated in FIG. 16, a 
given unit 24 can be controlled by its control computer from instructions 
by a host computer to move between units 20 and 22 and thereby provide 
substantial expansion without requiring additional units 24. To this end 
each unit 24 would include its own internal or external drive arrangement 
for moving it along a cooperating track 140. 
Turning now specifically to FIGS. 17-23, a number of details of the overall 
carriage assembly 56 will be described. In this regard, it is to be 
understood that these latter figures illustrate an actual working 
embodiment of the carriage assembly with various components missing for 
purposes of clarity. Also, it is to be understood that the actual 
components illustrated in FIGS. 17-23 and the corresponding components 
diagrammatically illustrated in the earlier figures are designated by the 
same reference numerals. 
Turning specifically to FIG. 17, both of the arm arrangements 62 and 64 are 
illustrated including their respective cross arms. The cross arms are 
shown mounted to opposite sides of carriage 58. Their respective hook 
members 112 and bumper members 114 on corresponding sides of the cross 
arms are shown in their raised, unactuated positions. FIG. 18 specifically 
illustrates the carriage segment 130 and shaft 74 about which it rotates 
to flip a disc assembly 12. FIG. 17 on the other hand illustrates a 
carriage assembly to accomplish this. Specifically, FIG. 17 illustrates a 
drive motor 160 connected through gears 162 to an endless chain 164 
supported by cooperating sprockets including one mounted to shaft 74 
(shown in FIG. 18). The drive motor, upon receiving commands from computer 
26, drives the chain in one direction or the other to rotate carriage 
section 130 in the desired manner. 
Still referring to FIGS. 17 and 18 in particular conjunction with FIGS. 
19-22, arrangements 66 and 68 for driving arm arrangements 62 and 64 are 
illustrated in detail. As indicated previously, the drive arrangement 66 
includes a drive motor 84 and the drive arrangement 68 includes a drive 
motor 86. The drive motor 84 is connected to and drives an endless drive 
chain 170 while the drive motor 86 is connected to and drives an endless 
drive chain 172. These drive chains are connected to the respective cross 
arms of arm arrangements 62 and 64 in the same manner as belt 120 is 
connected to the overall carriage itself, that is, by a connecting lug 
(not shown) on one side of each chain. In that way, as each chain 170 and 
172 is driven horizontally in one direction or the opposite direction, it 
moves its associated cross arm with it. It does so in either an 
acceleration mode or a torque mode, depending upon the commands by 
computer 26 under the circumstances discussed previously. Also, as stated 
previously, each of the drive motors 84 and 86, like carriage motor 82 
includes its own encoder and a servo-feedback circuit for monitoring the 
position of its cross arm in the manner described. 
Directing attention to FIG. 23 in conjunction with FIGS. 19-22, note the 
way in which a given pair of hook members 112 and a pair of bumper members 
114 are moved between their respective actuated and deactuated positions. 
To this end,. one of the cross arms, for example, cross arm 96, is 
illustrated apart from the rest of its arm arrangement. Cross arm 96 is 
shown with its hook members and bumper members in their deactuated 
positions. Each of the hook members on one side of the cross arm, for 
example the side shown in FIG. 23, are actuated by an electrically 
actuated solenoid 180 which is connected to both of the members through a 
linkage arrangement shown at least in part in FIGS. 19-23. A second 
solenoid 182 operates the hook members (not shown) on the opposite side of 
cross arm 96 through a similar cooperating linkage arrangement. A third 
solenoid 184 is connected through a similar linkage arrangement to the 
bumpers 114 shown in FIG. 23 and bumpers on the other side of the cross 
arm (not shown) so that all four bumpers on the cross arm are 
simultaneously actuated and deactuated together. 
Turning to FIGS. 24A and 24B, attention is directed to a specific detail in 
the linkage system between the solenoid 180 or 182 and its associated hook 
members 112. In particular, FIGS. 24A and 24B show solenoid 180 and one of 
the hook members 112. Note that the hook member is connected to the output 
of solenoid 180 through a series of three links 183, 184 and 186 which are 
pivotally connected to one another. FIG. 24A illustrates how these links 
are positioned when the solenoid places the hook member in its deactuated 
position and FIG. 24B shows how these links are positioned when the 
solenoid places the hook member in an actuated position. Note that the two 
links 183 and 184 are bent relative to one another in the FIG. 24A 
position while they are relatively straight in the FIG. 24B. In this 
latter figure, the two links 183 and 184 form a knee lock which is 
difficult to break without use of the solenoid itself. In this way, the 
knee lock serves as a means of locking the hook member 112 in an actuated 
position without requiring a large force from the solenoid itself. Once 
the solenoid breaks this knee lock, it can readily move to its deactuated 
position. A similar linking arrangement is provided for each of the other 
hook members. 
Overall system 10 has now been described including various specific 
features. Among those features which have been specifically described are 
ones that are considered important to the present invention while other 
features which have been described are those important to understanding 
the overall environment of the invention. Some features of the overall 
system have been illustrated in the drawings but not necessarily described 
and there are some readily providable features which have not been 
described or shown at all. Those features which have been illustrated but 
not described and those features which have not been either illustrated or 
described could be readily provided by those with ordinary skill in the 
art in view of the disclosure herein. Moreover, it is to be understood 
that the present invention is not directed to the actual computer software 
forming part of computer 26. It suffices to say again that an individual 
with ordinary skill in the art could readily provide the software required 
for computer 26 to operate the system along with the cooperating hardware 
including the appropriate communication links between the system, computer 
26 and a host computer. Further, while the present invention has been 
described with respect to information storage discs, it is in most 
instances equally applicable to other types of information storage media 
such as tapes. Moreover, the transport unit could be used to transport 
other objects between various points in its system.