Airplane cargo handling system

A cargo handling system for use in combination with an airplane cargo compartment having a floor structure and a door opening moves cargo placed in the loading area inside the compartment at the door opening to the further recesses of the compartment and returns the cargo to the loading area for unloading. The system generally comprises fore and aft end panels, each attached to its own looped cable and movable from a position adjacent its respective end of the compartment to a position adjacent its respective side of the door opening; a movable main panel attached to a power cable; a drive means, such as a hydraulic cylinder, is attached to the power cable and drives the main panel in the door area between the door positions of the end panels; and indexing plungers which selectively couple the main panel with a cable of an end panel such that, when coupled, the end panel is driven simultaneously with and in the same direction as the main panel. The cables and rolling supports for the panels move in passageways in drive strips which extend the length of the compartment. Roller strips, lining the compartment floor, reduce friction. Exemplary embodiments include a removable door adapter and ball mat which aid in loading bulk or containerized cargo. In the preferred embodiment, the hydraulic cylinder is in a power pack which is removably attached to the main panel.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates in general to an aircraft cargo handling system and 
more particularly to an improved method and device for loading and 
unloading cargo, both containers and bulk, in an aircraft belly 
compartment. 
2. Background of the Invention 
The cargo compartment in the belly of a commercial airliner is typically 
elongate and semi-circular in cross-section. The curved lower aircraft 
body structure generally defines both the bottom and side walls of the 
compartment. A common ceiling height is approximately forty five inches. 
Because of the low ceiling and curved floor, men cannot easily work in the 
compartment, and cargo handling is difficult. Manual loading is physically 
hazardous work. While in a crouched or crawling position, a person must 
lift and stack forty to fifty pound bags, boxes, and cases. Therefore, 
other methods have been attempted for belly compartment cargo handling. 
One method of belly compartment cargo handling comprises a series of pairs 
of conveyor belts and rollers mounted on the compartment floor. This 
method has been used in the Boeing 757. Incoming cargo is placed on a 
first pair of moving belts which conveys it to a second pair and then to a 
third pair and so on until the end of the available compartment space is 
reached. Each pair of belts must have its own motor, gearbox, and clutch, 
allowing it to be selectively activated so that it does not continue to 
run after its cargo can no longer move. 
This modular belt system has several drawbacks. The system is only 
practical for standard containers and cannot readily handle bulk cargo. It 
requires a considerable amount of the usable compartment space. With the 
many motors and drive components, the system is quite heavy and detracts 
from the airplane's carrying capacity. It is complex and expensive. 
Importantly, because the system is modular, if one motor fails, the others 
must carry the overload. At the least, the cargo remaining on a failed 
module must be removed by hand. 
In another prior art method, referred to here as the telescoping method, a 
series of successively smaller intersheaved shells lines the compartments. 
Upon loading, the shells are collapsed to a position adjacent the door 
opening whereby only the innermost shell is available for loading. After 
this innermost shell is loaded, it is extended into the compartment which 
permits the next shell to be loaded, etc. To unload, the cargo in the door 
area is removed, exposing the largest shell adjacent the door. When the 
largest shell is unloaded, the remaining shells are telescoped toward the 
door area and each is unloaded in sequence. The telescoping method is 
heavy and requires a different shell shape for each aircraft shape. It 
handles bulk cargo only. The shells take up considerable cargo volume 
since each shell is approximately one inch thick. The shells are easily 
damaged and can hang up and otherwise malfunction. 
Therefore, it is desirable to have a powered cargo loading system for an 
aircraft belly compartment which is simple, reliable and can handle both 
bulk and containerized cargo, singly or intermixed. 
It is further desirable that such a system be designed to minimize possible 
failure modes and that the most failure-prone components can be quickly 
replaced with minimal cargo removal. 
It is further desirable that the system be light weight and require only a 
small volume. It is further desirable that the system is easily adaptable 
to the different aircraft shapes using common components. 
SUMMARY OF THE INVENTION 
This invention is a cargo handling system for use in combination with an 
airplane cargo compartment having a floor structure and a door opening. 
Except as noted, the system elements are disposed within the compartment. 
The system moves cargo placed in the loading area inside the compartment 
at the door opening to the further recesses of the compartment and returns 
the cargo to the loading area for unloading. 
The system generally comprises fore and aft end panels, each attached to 
its own looped cable and movable from a position adjacent its respective 
end of the compartment to a position adjacent its respective side of the 
door opening; a movable main panel attached to a power cable; a drive 
means, such as a hydraulic cylinder, is attached to the power cable and 
drives the main panel in the door area between the door positions of the 
end panels; and indexing plungers which selectively couple the main panel 
with a cable of and end panel such that, when coupled, the end panel is 
driven simultaneously with and in the same direction as the main panel. 
According to a further precept of the invention, the floor of the 
compartment is lined with a plurality of roller strips including roller 
panels which are arranged in removable sections. The cables and rolling 
supports for the panels move in passageways in drive strips which extend 
the length of the compartment. 
According to an exemplary embodiment, the system includes a door adapter to 
aid in loading bulk cargo. The door adapter includes a hinged panel 
mounted in and traversing the door opening. The hinge axis is adjacent the 
door sill. In a lowered position, the panel serves as a platform, protects 
the door sill, and does not obstruct the door opening. In a raised 
position, the adapter covers the bottom portion of the door opening and 
allows bulk cargo to be stacked to a greater height and width in the 
loading area. 
In the preferred embodiment, the hydraulic cylinder is in a power pack 
which is removably attachable to the main panel. As this contains the 
parts most subject to malfunction, its easy replacement reduces down time 
and airplane delay. 
In operation, cargo to be loaded is placed in the loading area and the main 
panel is driven to push the cargo toward a compartment end. The main panel 
is returned, more cargo is loaded into the loading area, and the main 
panel is driven to push this cargo and the previous cargo. This is 
repeated. To unload, any cargo in the loading area is unloaded, the main 
panel is moved to its position adjacent the end from which cargo is to be 
unloaded, and the main panel is indexed to the cable attached to that end 
panel. The main panel is driven across the loading area, also pulling the 
end panel toward the door. The end panel pushes the cargo ahead of it 
toward the loading area. This is repeated as necessary. 
Other features and many attendant advantages of the invention will become 
more apparent upon a reading of the following detailed description 
together with the drawings in which like reference numerals refer to like 
parts throughout. The drawings disclose by way of example, and not by way 
of limitation, the principles of the invention and the structural 
implementations of the inventive concept.

DETAILED DESCRIPTION OF THE INVENTION 
With reference now to the drawing, and more particularly to FIG. 1 thereof, 
there is shown a perspective view, partially cut away, of the major 
visible components of the cargo handling system, denoted generally as 10, 
of the invention as they are situated in the belly compartment of an 
airplane (not shown). The airplane's outer skin 15 and my reinforcing 
ribbing 16 (seen in FIG. 3) define the floor structure of the compartment. 
Compartment door 11 is shown by phantom lines to illustrate its typical 
cargo loading position, i.e. rotated outward and upward, relative to the 
compartment. That portion of the compartment inside the doorway and into 
which cargo can be placed is referred to as the loading area. Also, since 
the compartment typically has a concave floor structure which curves 
upward to form side walls which may or may not be vertical, and there may 
be no demarcation between floor and wall; the term "compartment floor" as 
used herein refers to such of this structure may support cargo and 
generally includes all structure below the ceiling. 
The cargo handling system includes friction reduction means, such as roller 
strips 70, which generally line the floor of the compartment, and may 
include ball mat 14 in the loading area. A preferred embodiment of a 
roller strip, denoted generally as 70, is illustrated in FIG. 2 and 
includes rails 72 and a roller panel, denoted generally as 74. As best 
seen in FIG. 2b, roller panel 74 includes an upper surface 78, a plurality 
of roller apertures 75, and support flanges 76, which extend from its 
lower surface. A pair of rollers 80 are mounted on an axle, such as 
shouldered pin 81, which is supported on its ends by a pair of flanges 76. 
Rollers 80 project thru apertures 75 and protrude above panel upper 
surface 78. As seen in FIG. 2c, D-shaped flange hole 77 receives shoulder 
pin 81 and prevents its rotation. Suitable means, such as cotter pin 82, 
provides for easy removal and replacement of rollers 80. 
As seen in FIG. 2a, rails 72, permanently attached to the floor structure, 
support roller panel 74 such that rollers 80 can turn freely. Typically, 
rails 72 are one inch in height, and rollers 80 are one inch in diameter. 
Roller sets 80 within a panel are mounted within a short distance from one 
another; preferably within approximately three and one-half inches. The 
top of each rail 72 supports the outside edge of two abutting roller 
panels 74 such that rollers 80 and the upper surface 78 form a continuous 
cargo-supporting surface. Roller panels 74 are removably fastened to rails 
72, preferably by a quick-release method, such as by T-shaped, 
quarter-turn retained pin 84. Retained pin 84 passes thru hole 73 in rail 
72 and is held by W-type snap ring 85 and is upward biased by preload 
spring 86. Notches 87 in the outside edge of roller panel 74 accommodate 
passage of the stem of retainer pin 84 and allow adjacent roller panels to 
abut. Formed deflectors 88 in the roller panel upper surface 78 prevent 
cargo from snagging on retainer pins 84. In the exemplary embodiment, 
roller panels 74 are in suitable modular lengths, such as forty inches, 
and are of narrow enough width, such as three and one-half inches, so that 
they may conform to the curved compartment wall. A ninety degree turn of 
retainer pin 84 either locks or unlocks the edge of both adjacent roller 
panels for their removal and replacement. 
The narrow width of roller strips 70 allows them to conform to any of the 
several aircraft body shapes and to present a continuous, low-friction, 
bulk cargo transporting surface. FIG. 3 illustrates this ability. FIG. 3 
is a cross-sectional view of an aircraft belly compartment which is fully 
radiused, such as on the DC8and DC9. The airplane outer skin 15 and 
support structure, such as rib 16, define the floor of the compartment. 
Compartment ceiling 17 is the floor structure for the airplane cabin. 
Roller strips 70 are mounted on the floor structure. Their narrow width 
allows them to conform quite closely to the contours of the belly 
compartment. 
FIG. 3 also shows the ability of roller strips 70 to support and handle 
standard containerized cargo. In cross-section, the bottom of a typical 
standard cargo container 18 has a flat mid-section 19 and radiused outer 
portions 20. The flat bottom is required to adapt to the terminal conveyor 
systems. Container 18 is fully supported by the roller strips 70 in the 
curved portion of the compartment. Volume loss of the flat-bottomed 
container 18 in a radiused belly is normal. However, bearing container 18 
on the rollers in the curved portion of the belly precludes the addition 
of a continuous "flat" floor with its considerable weight and cost 
increase. For handling containerized cargo, ball mat 14 (see FIG. 1) which 
may be removable, is located on the floor of the loading area. 
Returning once more to FIG. 1, the importance and advantages of roller 
strips 70 can now be better appreciated. The compartment floor may include 
a flat center section 13 as is common on airplanes such as the 727, 737, 
and 757. Roller strips 70 cover the floor of the compartment. Roller 
panels 74 are installed in sections beginning at the door area. For 
example there may be as many as five modular roller panel sections to 
either side of the loading area. Because cargo enters the compartment thru 
door 11 and is rolled fore and aft, the rollers nearer the door are used 
much more and subsequently wear more than the more remote rollers. 
Sectional installation of the roller panels 74, coupled with their ease in 
removal and replacement, allows the sections nearer the door to be 
replaced more often or, alternately, permits the exchange of the roller 
panels between sections to provide for even wear of all rollers. Also, if 
individual rollers 80 fail, it has been seen from the discussion of FIG. 2 
that these are easily individually replaced. 
Main drive panel 30, aft panel 50, and fore panel 60 approximate the 
cross-sectional area of the compartment in area and are movable 
longitudinally, i.e. fore and aft, in the compartment. Aft panel 50 is 
movable from its shown position, remote from the door and defining the aft 
end of the compartment, to a position near the aft side of the door 
opening. Fore panel 60 is movable from its position shown, remote from the 
door opening and defining the fore end of the compartment, to a position 
near the fore side of the door opening. Typically, in their remote 
positions, the fore and aft panels would abut bulkheads. 
The main drive panel drive means may include power pack 95, which is 
described in greater detail later in reference to FIG. 7. Main drive panel 
30 is drivable thru the distance D between position A, shown, which is 
immediately adjacent the fore most position of aft panel 50, and position 
F, shown in phantom lines, which is immediately adjacent the aft-most 
position of fore panel 60. Distance D, defined as the loading distance, is 
approximately the width of the door in the exemplary embodiment. 
Preferably, the lengths of both sides of the compartment, i.e. from point 
A to the compartment aft end and from point F to the compartment's fore 
end, are multiples of the loading distance D. The displacement of the 
drive panel moving distance D is defined as the loading volume. The 
section of the compartment demarcated by the fore and aft positions of 
main drive panel 30 shall be referred to generally as the loading area. 
In FIG. 1, for descriptive purposes, the door opening is shown to be in 
mid-compartment so that cargo can be loaded both fore and aft. However, it 
will be seen that the invention is easily adaptable to the situation where 
door 11 accesses a compartment immediately adjacent a bulkhead so that 
cargo can only move one direction. 
Bulk cargo entering the compartment is placed into the loading area from 
which it can roll longitudinally on rollers 80. Optional ball mat 14 is 
shown on the floor of the loading area. Ball mat 14 supports containers 
and allows them to be rolled into the loading area from the side. 
Two drive strips 90 (shown on darker shade) run the length of the 
compartment and provide means for longitudinally moving panels 30,50,60. 
FIGS. 4 and 5 illustrate an exemplary embodiment of an alternate means for 
moving the panels. FIG. 4 is a partially cut away, perspective schematic 
view of an exemplary embodiment of the major components of a panel moving 
means. FIG. 5 is a cross-sectional view of an exemplary embodiment of a 
drive strip 90 along line 5--5 of FIG. 1 and illustrates the 
interrelationship of the panels 30,50,60 with the drive strip 90 and drive 
means. In general, main drive panel 30 is driven over the loading distance 
D by drive panel drive means including power stroke means, such as powered 
screw or hydraulic cylinder 40, and main drive panel drive transmission 
means including a flexible tension member, such as drive panel power cable 
42, and anchored routing pulleys 47 (not all numbered). 
The flat central floor configuration of FIG. 1 is common in 727 and 757 
type aircraft. In these aircraft, the flat section 13 is approximately 
fifty inches wide. In this configuration, cylinder 40 could be located 
beneath the floor of the loading area and attached to the airplane 
structure in any powering and activating the drive panel drive means and 
such is not within the confines of this invention and will not be 
discussed in detail. 
In the exemplary embodiment, drive power cable 42 may be thought of as a 
single cable having end anchors 43,44. It is connected to support footings 
32 of drive panel 30 from both fore and aft. In FIG. 4, drive panel 30 is 
shown in its full aft position A. Hydraulic cylinder 40 moves power 
pulleys 45. To move drive panel 30 to fore position F, cylinder 40 moves 
power pulleys 45 thru stroke S from position A1, shown, to position F1, 
shown in phantom. Since, in this exemplary embodiment, this distance is 
one-fourth of loading distance D and the pulley ratio is one-to-four, 
drive panel 30 is driven distance D to the fore position F. It can be seen 
that the cable routing configuration shown completely manages cable 42 by 
simultaneously feeding out cable 42 attached to the front of support 
fittings 32 of drive panel 30 and taking in cable 42 attached to the back. 
Reversing the direction of the power stroke again moves the power pulleys 
45 thru distance S from position F1 to position A1, whereby main panel 30 
once more is driven thru distance D, this time from position F to position 
A. 
Aft panel 50 is attached to and driven by a looped flexible tension member 
assembly including aft cables 52. Fore panel 60 is also attached to and 
driven by a looped flexible tension member assembly including fore cables 
62. Fore and aft cables 62,52 are in the shape of a loop and turn around 
pulley rollers at each endpoint. Indexing means, such as a plurality of 
swaged lugs 99 attached at intervals to cables 52,62 allow the cables and 
attached aft and fore panels 50,60 to be driven. Lugs 99 could be standard 
cylindrical tube lugs swaged onto the cable. Although cables and swaged 
lugs are shown as fore and aft panel drive transmission means, it is 
understood that other similarly functioning elements, such as chains or 
the like, could be used and are intended to be covered by the inventive 
concept of this invention. 
FIG. 5 is a cross-sectional view taken along line 5--5 of FIG. 1. FIG. 5 
illustrates a cross-sectional view of an exemplary embodiment of the port 
drive strip 90 in the loading area. The starboard drive strip is similar. 
Preferably, drive strip 90 is narrower in width than roller strips 70. 
Drive strip 90 is mounted on floor structure 12 and can support the roller 
panels 74 on either side, as is shown. top surface 91 is below the top of 
adjacent rollers 80, which support and transport cargo. Drive panel 
support fitting 32 is connected to and is movably supported by a plurality 
of spaced apart bearings 33, which roll in channel track 92 of drive strip 
90. Spaced bearings 33 and channel track 92 counter moment induced to a 
panel when it pushes cargo. Drive panel power cable 42 attaches to both 
fore and aft of support fitting 32. Thus, it is seen how main drive panel 
30 is driven. 
Both forward and aft panels 60,50 are likewise movably supported by 
equivalent support fittings 32 and bearings 33 running in channel tracks 
92 of drive strips 90. 
Aft cable passageway 54 and fore cable passageway 64 within drive strip 90 
are each comprised of top and bottom chambers in which the top and bottom 
runs 52a, 52b and 62a, 62b of their respective cables are disposed. Cable 
engaging means, such as aft panel indexing plunger 34 and forward panel 
indexing plunger 36, are mounted in drive panel 30. Plungers 34,36 are 
lowered to engage their respective cables 52,62. Aft indexing plunger 34 
is shown in the lowered, cable engaging position, and fore indexing 
plunger 36 is shown in the raised, disengaged position. When an indexing 
plunger is lowered, the lower end of the plunger is designed to engage a 
lug 99, as shown. Upon longitudinal movement of drive panel 30, the 
engaged lug 99, the cable and attached fore or aft panel are similarly 
moved. Indexing plungers 34,36 may be activated by any of several means, 
such as manual or hydraulic, which would be obvious to one skilled in the 
art and the exact nature of which is not germane to this inventive 
concept. Appropriate controls for the elements of the invention could be 
located on an outside edge of main drive panel 30 or other location 
accessible by loading personnel. 
FIG. 6 is a representation of the operating sequence for handling cargo in 
the aft section of a cargo compartment using the system of the present 
invention. The cargo compartment, denoted generally as 22, terminates at 
fore bulkhead 24 and aft bulkhead 26 and includes aft compartment 22a and 
fore compartment 22b. Referring to FIG. 6a, when compartment 22 is empty, 
main drive panel 30, fore panel 60, and aft panel 50 typically are located 
in the positions shown. Cargo X, either bulk load or container, is loaded 
into the loading area. Referring to FIG. 6b, the drive means for main 
drive panel 30 is activated, thereby moving main panel 30 loading distance 
D from point F to point A. Main drive panel 30 forces cargo X and aft 
panel 50 aft a loading distance. In FIG. 6c, drive panel 30 is driven to 
position F. In FIG. 6d, cargo Y is loaded into the loading area. In FIG. 
6e, the main drive means is activated to move panel 30 aft one loading 
distance, thereby pushing aft both cargo loads X,Y and aft panel 50 in 
front of it. This sequence is repeated until the aft section of the 
compartment is full as is shown with the inclusion of cargo Z in FIG. 6f. 
Although only three cargo loadings X,Y,Z are shown as filling the aft 
section 22a of the compartment, typically a fore or aft compartment 
section may hold as many as five loading segments. 
The unloading sequence is shown starting with FIG. 6f. With drive panel 30 
at position A, aft plunger 34 is engaged. In FIG. 6g, the main drive panel 
drive means is activated to move drive panel 30 and aft panel 50 foreward 
loading distance D. Aft panel 50, driven by its cable 52, pushes all of 
the aft cargo X,Y,Z ahead of it, moving cargo Z into the loading area. 
Cargo Z in the loading area can now be offloaded. This sequence is 
repeated to unload the aft compartment. 
Loading and unloading of fore section 22b is basically the reverse of the 
sequence described above with fore plunger 36 engaging and disengaging 
fore cable 62. 
FIG. 7 is an exploded perspective view of a preferred embodiment of the 
main drive panel and its drive means. The embodiment of FIG. 7 further 
simplifies the replacement of those parts most likely to fail and, 
therefore, reduces down time and the resulting delay of aircraft 
departure. This is a simplified configuration in that the main panel drive 
means is contained on or within drive panel 30. This allows the main drive 
panel to be contoured to fit any narrow body aircraft (727, 757, F100, 
DC8, DC9) irrespective of whether it has a flat floor or full radius type 
belly compartment. 
In FIG. 7, a power pack, denoted generally as 95, includes housing 28 and 
is removably attached to the top of main panel 30 by quick release 
fittings 94. Power pack 95 contains the power stroke means, such as 
hydraulic cylinder 40 and its reservoir 46, pump 48, valves 49, and hoses. 
Hydraulic cylinder 40 powers push rod 41 nd hole 97 on its end thru stroke 
S. 
A control panel 96 on the door-side end of power pack 95 houses the 
controls for hydraulic cylinder 40 and the indexing plungers 34,36 for 
driving aft and fore panels 50,60. A stress monitor gage, movement rate 
control, and other features could be provided on control panel 96. Power 
may be supplied to power pack 95 by any suitable means from the aircraft 
electrical system or from a ground power source. 
The main drive panel drive transmission means, which translates the 
movement of push rod 41 into movement of main panel 30 and which is 
primarily disposed within main drive panel 30, includes power connection 
means, denoted generally as 170, fore and aft drive cables 65,55, and a 
plurality of routing pulleys 47' (not all numbered). Power connection 
means 170 includes pin 172 which exits the top of panel 30 thru a slot, 
enters housing 28 thru slot 27, and connects with hole 97. Pin 172 is 
mounted on trolley 174 which includes sets of spaced wheels 176 ride in 
channel tracks, not shown. Fore and aft drive cables 65,55 are anchored at 
one end 66,55 respectively within the drive strip and at the other end to 
trolley 174. From the configuration shown, it can be seen that outward 
movement of push rod 41 moves trolley 174 so as to drive main panel 30 in 
the aft direction, and inward movement of push rod 41 drives panel 30 in 
the fore direction. Trolley 174 takes up the moment forces of the power 
transfer so that fore and aft drive cables 65,55 receive only tension 
forces. 
Other than the change of location of the main panel drive means and the 
other associated changes discussed above with respect to FIG. 7, the 
remaining components of the cargo handling system, including support 
fittings 32' and bearings 33', are basically the same as described 
previously and the system operates in the same manner. 
It can be seen that the power pack embodiment of FIG. 7 allows for quick 
change of the drive and power components of the cargo handling system that 
are most likely to fail. It is envisaged that the ground crew will have 
spare power packs handy. 
FIG. 8 is a perspective view of a typical door opening 100 including frame 
101 to an airliner belly cargo compartment showing a door adapter, denoted 
generally as 110, for use in combination with the cargo handling system as 
described above when handling bulk cargo. Compartment door 11, not shown, 
typically is hingedly connected to the upper door frame and is latched to 
the lower frame with pins that enter holes in the frame. To load cargo the 
door is unlatched and is swung up and out of the way. 
Bulk cargo door adapter 110 is attached to an airplane upon cargo loading 
and unloading. Adapter 110 includes a frame, denoted generally as 120, and 
hinged panel, denoted generally as 140, which is shown in broken view with 
an open section at position 140a and a raised section at position 140b. 
Frame 120 includes left and right vertical members 122,124 and cross 
member 126. The upper ends of vertical members 122,124 are attached to the 
door pin holes in the lower door jamb. Pads 123,125 on the lower end of 
vertical members 122,124 rest against airplane outer skin 12. Cross member 
126 connects the vertical members outside of the door frame and includes 
arms 127 extending to the door sill 130. Hinges 142 connect the lower end 
of hinged panel 140 to end of arms 127 at the door sill. Hinged panel 140 
extends across the door opening and protects door sill 130. Hinged panel 
140 has a first position, denoted by broken view 140a, in which it is 
generally horizontal and is supported by frame 120. In this position, 
hinged panel 140 can support loading personnel and accommodate loading 
conveyers so that the loading area can be filled out to the door sill. At 
this time, hinged panel 140 is raised to position 140b and held by latches 
150. The remaining volume in the door area can then be loaded by passing 
cargo over the top of hinged panel 140. The inner surface of panel 140 is 
curved to match up with the compartment wall and provide a smooth matching 
contour for cargo being moved into or out of the loading area. 
From the foregoing description, it is seen that that the present invention 
provides an extremely simple, efficient, and reliable manner of handling 
both bulk and container cargo in an airplane belly compartment. 
Additionally, the system does not require any basic aircraft modifications 
and is easily adaptable to all compartment configurations. 
Although particular embodiments of the invention have been illustrated and 
described, various changes may be made in the form, construction and 
arrangement of the parts herein without sacrificing any of its advantages, 
and it is to be understood that all matter herein is to be interpreted as 
illustrative and not in any limiting sense. Accordingly, the present 
invention is to be construed as limited only by the spirit and scope of 
the appended claims. 
For brevity, as used in the following claims, the word "cable" denotes a 
flexible tension member, such as a cable, chain, or the like.