BACKGROUND OF THE INVENTION
[0001] This invention relates to shipping containers for flowable substances and, more particularly,
to heavy-duty shipping containers for the bulk transport of flowable bulk materials,
including liquids, dry powders or granular substances, semi-solid materials such as
grease, pastes or adhesives and, as well, highly viscous fluids, in volumes of at
least fifty-five gallons and in quantities of weight greater than four hundred-fifty
pounds.
[0002] Shipping containers used for the transport of flowable bulk materials must accommodate
extraordinary weight, due to the high density of the contained materials and, at the
same time, must be designed to withstand damage that can result from the nonuniform
and sometimes cyclic stresses caused by the material shifting during the handling
and transport of the container. Even a minor puncture or crack can cause the total
loss of the flowable material. Heavy-duty shipping containers containing bulk flowable
materials exceed the limits of manual handling capability and are typically mounted
on pallets and handled by mechanical means such as fork lifts and hand-lift trucks.
[0003] Various types of containers and container materials have been designed for the transport
of flowable bulk materials. Single wall (double face) corrugated fibreboard boxes,
for example, have been used as inexpensive, disposable containers for light-duty applications.
Such fibreboard containers, where necessary, are waxed or provided with a plastic
liner bag. As the volume and weight of the contained material increases, however,
the pressure of the material within the container causes bulging of the sides of the
container. This makes the container difficult to stack with other similar containers.
Furthermore, the bulging of the sides of the container significantly reduces the inherently
limited column strength of single wall containers making this type of container unsuitable
for stacking or heavy-duty application.
[0004] The term fibreboard is a general term applied to paperboard utilized in container
manufacture. Paperboard refers to a wide variety of materials most commonly made from
wood pulp or paper stock. Containerboard refers to the paperboard components -- liner
and corrugating material -- from which corrugated fibreboard is manufactured. Thus,
the term fibreboard, as used in the packaging industry and in the present specification
and claims, is intended to refer to a structure of paperboard material composed of
various combined layers of containerboard in sheet and fluted form to add rigidity
to the finished product. Fibreboard is generally more rigid than other types of paperboard,
allowing it to be fabricated into larger sized boxes that hold their shape and have
substantial weight bearing capability.
[0005] Double or triple wall corrugated fibreboard, when made into shipping containers,
provides many distinct advantages for the packaging and transport of heavy loads.
Double wall corrugated fibreboard comprises two corrugated sheets interposed between
three flat facing or spaced liner sheets. In triple wall corrugated fibreboard, three
corrugated sheets are interposed between four spaced facing or liner sheets. Triple
wall corrugated fibreboard, in particular, compares favorably with wood in rigidity
and strength and, as well, in cost, and provides cushioning quality not found in wooden
containers. In addition, triple wall corrugated fibreboard, relative to other fibreboard
materials, advantageously provides great column strength. The column strength of triple
wall corrugated fibreboard containers permits stacking, one on top of the another,
of containers containing heavy loads without excessive buckling or complete collapse
of the vertical walls. Triple wall corrugated fibreboard also has great resistance
against tearing.
[0006] F ibreboard shipping containers employing an outer multi-sided
tubular member and a simularly configured inner reinforcement to strengthen the overall
container have been disclosed. See, for example, U.S. Patents 3,159,326, 3,261,533,
3,873,017, 3,937,392, 4,013,168 and 4,418,861.
[0007] In order to form multi-sided fibreboard tubes, it is necessary to form major score
lines in the fibreboard to allow bending of the fibreboard along the edges of each
panel of the container which is formed. However, scoring adversely affects the container
since the lateral stability of the container significantly decreases as the number
of major score lines is increased. The major scoring of the container typically permits
the container, when empty, to be shipped in a knocked down, flat condition.
[0008] Circular cylindrical-shaped containers have long been regarded as the most efficient
shape to use in containing liquids or dry flowable products. Paperboard designs utilizing
circular cylindrical type containers, however, have been restricted to small capacity
cylindrical shapes typlified by the 55 gallon capacity spiral wound fibre drum. Producing
larger containers of this type has proven impractical, on a commercial basis, due
to a number of reasons including excessive material and fabrication costs and the
unavailability of fabricating equipment. Moreover, the fibre drums are rigid and cannot
be folded into a flattened state when empty. Since existing technology requires that
these fibre drums be pre-erected at a central location and then shipped to and stored
empty in an erected or pre-formed condition at user locations, the utilization of
cylindrical fibre drums also presents handling, shipping, and storing difficulties.
Most importantly, the structural performance and handling requirements of a fibre
drum, as capacity climbs to the 110 gallon to 380 gallon range, have exceeded the
industry's ability to produce a readily available commercial product. Utilization
of higher-strength reinforced plastic or metal drums has not provided a satisfactory
alternative as such materials are typically more expensive, do not increase utilization
of cubic storage space, when empty, and present a variety of disposal problems.
[0009] Thus, despite the efficiencies of circular cylindrical containment, corrugated fibreboard
has not been generally used as a circular cylindrical container material. Corrugated
fibreboard, particularly in the heavier grades of multi-wall fibreboard capable of
containing and supporting the weights and hydrostatic pressures produced by 110 to
380 gallons of contained liquid, or an equal volume and weight of flowable solids,
does not lend itself to being fabricated into circular cylindrical shapes without
substantial loss of key performance features of corrugated fibreboard, that is, top
to bottom compression strength and lateral stability.
SUMMARY OF THE INVENTION
[0010] The invention is directed to a heavy-duty shipping container for bulk materials comprising
an inner tubular sleeve of a multi-wall corrugated fibreboard of substantially circular
cross section, adapted to contain a flowable bulk material, and an outer sleeve of
polygonal cross section assembled about the inner sleeve for its full length, the
outer member also being constructed of a multi-wall corrugated fibreboard. The inner
circumferential facing of the inner sleeve is formed with a plurality of false scores
extending lengthwise, i.e. substantially parallel to the length of the inner sleeve
or parallel to the flutes or corrugations thereof.
[0011] The outer sleeve is preferably constructed of triple wall corrugated fibreboard and
is preferably octagonal in cross section.
[0012] The inner sleeve is a corrugated fiberboard sleeve in the form of a right circular
cylinder formed of a multi-wall corrugated fibreboard such as double wall or, preferably,
a triple wall corrugated fibreboard which has been subjected to a bending process
to form the false scores randomly at intervals of one to six inches.
[0013] Preferably, the outer sleeve of the container is provided with bottom end flaps of
single-wall corrugated fibreboard and is provided with a removable upper end cap formed
from folded corrugated fibreboard.
[0014] When formed, shipping containers made in accordance with the invention are designed
to contain flowable materials in volumes of at least 55 gallons and weights exceeding
four hundred-fifty pounds.
[0015] Shipping containers of the invention, in comparison to steel or fibre drums presently
in use, per unit of volume are less costly on a material and fabrication basis. The
shipping containers of the invention provide increased utilization of cubic storage
space when the containers are being shipped or stored empty in that the inventive
shipping containers can be folded flat when not is use. Moreover, since the materials
employed have recycle salvage value and, as well, are biodegradable, post-use disposal
does not present problems associated with plastic and metallic containers.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] In the accompanying drawings, forming a part of this specification, and in which
reference numerals shown in the drawings designate like or corresponding parts throughout
the same,
Figure 1 is a schematic perspective view of a shipping container, partly broken away,
formed in accordance with the invention;
Figure 2 is a top view of a shipping container, with the top cap removed, formed in
accordance with an embodiment of the invention;
Figure 3 is an enlarged view of the encircled detail of Fig. 2;
Figure 4 is a section of a portion of a side and the bottom of the shipping container
of Fig. 1;
Figure 5 is a top plan view illustrating a blank, prior to false scoring, from which
an inner sleeve of the shipping container may be formed;
Figure 6 is a top plan view of a blank from which an outer sleeve of the shipping
containers may be formed;
Figure 7 is a sectional view taken along line 7-7 of Fig. 6;
Figure 8 a perspective view showing on end flaps of and outer sleeve of the shipping
containers; and
Figure 9 is an exploded schematic view, in perspective, illustrating a shipping assembly
embodying the invention.
DETAILED DESCRIPTION
[0017] The shipping container 10, as disclosed herein, is constructed with a right circular
inner cylindrical sleeve 12 of a multi-wall corrugated fibreboard substantially coaxially
received within an outer sleeve 14 of a multi-wall corrugated fibreboard which has
a polygonal cross section as best shown in Figures 1, 2 and 3.
[0018] The inner sleeve 12 is a multi-wall corrugated fibreboard which may consist of a
single wall or double wall corrugated fibreboard for certain applications. In accordance
with the preferred embodiments of the invention, the inner sleeve 12 is preferably
composed of triple wall corrugated fibreboard as is illustrated by Figure 4. Corrugated
fibreboard, particularly heavy grades such as double and triple wall corrugated fibreboard,
when used for inner sleeve construction, dramatically increases the stacking strength
of the overall container as compared to a solid fibre and single wall inner sleeves.
[0019] The inner sleeve 12, in the preferred embodiment, is formed from a flat sheet 11
of triple wall corrugated fibreboard. The flat sheet 11, as shown in Figure 5, is
first formed with two major score lines 13, 17, provided preferably at diametrically
opposite locations on the assembled inner sleeve 12, to allow the inner sleeve to
be shipped, when empty, in a knocked down condition, with a uniform folded slope.
The flat sheet 11 is circularly shaped in a bending apparatus, such as a sheet metal
roller or a modified four bar slitter, by subjecting the corrugated sheet to a prebreaking
process. The prebreaking process comprises pa ssing the
corrugated sheet through a curved path having a radius of curvature which causes the
random formation of multiple scores 75, so-called false scores, running in the direction
of the corrugations, on the smaller radius of the curved sheet. The randomly spaced
false scores 75, which in the case of a triple wall corrugated fibreboard occur variously,
approximately from one to six inches apart, help facilitate the formation of a nearly
perfect cylindrical shape of the inner sleeve 12, when the inner sleeve is placed
within the outer polygonal sleeve, and filled with a liquid or flowable solid substance.
Besides providing these random scores, the prebreaking process also stretches the
outer facing of the corrugated fibreboard sheet, and compresses the inner facing to
the extent that when assembled into a sleeve, and secured by a glue joint, the sleeve,
although it can be folded flat, maintains a circular cylindrical shape when erected.
The end portions of the sheet, which comprises the circular inner sleeve, are overlapped
and adhesively combined in a lap joint. The outer circumferential facing of the inner
sleeve is not creased or scored but remains smooth.
[0020] The randomly-spaced false scores 75 of the corrugated fibreboard sheet, when assembled
into a sleeve configuration, extend generally parallel to the longitudinal axis of
inner sleeve 12. As used herein, it should be understood that the terminology "false
scores" does not comprise score lines of the type which are formed with a scoring
tool but are the type of scores known in the fibreboard industry as "false scores"
which result from the application of prebreaking stress to sheetstock materials. As
best shown in the enlarged detail view provided in Figure 3, the false scores only
crease the innermost (on the small diameter side of the sleeve) facing of the inner
sleeve 12 of triple wall fibreboard. In comparison, the mechanical scores 13, 17 formed
to allow folding of the inner sleeve blank crease the innermost facing and, as well,
the intermediate facings and flutes of the triple wall fibreboard comprising the inner
sleeve 12. It is critical that the described false scores be used to obtain the circular
configuration of the inner sleeve as, for example, use of a multiplicity of numerous
mechanical score lines would debilitate the strength of the inner sleeve.
[0021] Outer sleeve 14, in accordance with a preferred embodiment of the invention, comprises
a tubular member having an octagonal cross section. The outer sleeve 14 is formed
from a substantially rectangular sheet 16 of corrugated fibreboard, or equivalent,
shown in Figure 6. The rectangular sheet 16 is die cut and scored for folding, by
techniques well understood in the art, and includes a plurality of substantially rectangular
wall panels 18, 20, 22, 24, 26, 28, 30 and 32, foldably connected to each other by
lateral score lines 34, 36, 38, 40, 42, 44, 46 and a sealing flange 48 foldably connected
to wall panel 32 via a lateral score line 50. End flaps 52, 54, 56, 58, 60, 62, 64,
66 are formed at one of the opposite edges of the respective wall panels and are foldable
along score lines 51, 53, 55, 57, 59, 61, 63, 65 which are formed on the end flap
approximately one-eigth inch from the bottom edge 68 of the wall panels. The wall
panels are preferably formed from triple wall corrugated fibreboard which, as shown
in Figure 7, include three corrugated sheets 70, 72, 74. The ridges of the corrugated
sheets are adhesively secured to liner sheets 76, 78, 80 and 82. The end flaps are
preferably formed of single wall corrugated fibreboard, as shown in Fig. 8. which
is integral to the triple wall side wall panels. The end panels may be formed on a
triple wall combiner machine as part of the combiner process in a manner well-known
to those skilled in the corrugated fibreboard container industry.
[0022] The rectangular sheet 16 is bent along the lateral fold lines into the form of an
octagon, when viewed in cross section. The sealing flange 48 overlaps the exposed
face of liner 76 and is adhesively secured thereto, in a known manner, to form outer
sleeve 14. The end flaps are then sequentially folded inwardly of the outer sleeve
14 so that adjacent flaps overlie each other. The use of end flaps adds to the structural
integrity of the container. The end flaps can be omitted and a lower end cap, similar
to the upper end cap, employed with less favorable results. Alternatively, both a
bottom end cap and bottom end flaps can be utilized.
[0023] The inner sleeve 12 is then inserted into the outer sleeve 14. The outer sleeve 14
is sized such that the wall of the inner sleeve 12 touches at approximately the mid-point
of each of the walls of the outer sleeve 14 as typically shown at 15. Gaps 19 are
formed between the inner sleeve 12 and the corners of the outer sleeve 14, the corners
being defined by the lateral score lines between the wall panels of the outer sleeve
14.
[0024] Although the outer sleeve 14 is shown as octagonal in cross section, it will be appreciated
that any polygonal cross section may be utilized.
[0025] The container 10 is preferably closed at its top by a removable end cap 90, which
has a cross section similar to that of the outer sleeve and, thus, in the illustrated
embodiment has an octagonal configuration. End cap 90 has a downwardly extending peripherial
side flanges 92 which extend outside and are engageable with the ends of the outer
sleeve below the upper edge of the outer sleeve 14. The end cap 19 is not a load bearing
member and, therefore, may be formed from single wall corrugated fibreboard.
[0026] Figure 9 illustrates a shipping assembly in accordance with the invention. A separate
pallet 96 of conventional construction is employed beneath the shipping container
to facilitate movement of the containers by a fork lift or hand lift truck.
[0027] A bottom pad 98 is preferably inserted into the outer sleeve 14 and rests upon the
infolded end flaps 52, 54, 56, 58, 60, 62, 64. The bottom pad 98, in the illustrated
embodiment, has an octagonal-shaped cross section and is designed to be closely received
within the outer sleeve 14. The peripheral edges of the bottom pad 98 bear against
the side walls of the outer sleeve 14. The bottom pad 98 is preferably composed of
triple wall corrugated fibreboard.
[0028] A plastic liner bag 100 is preferably provided within the inner sleeve 12 to leak-proof
the container. The liner bag 100 precludes the flow of the contained materials between
the interstices that may exist in between the end flaps and at the bottom pad. A suitable
liner bag 100 can be made from a flexible plastic film material, such as polyethylene
extruded film or the like.
[0029] In certain applications, a compressible top pad 102 with a circular cross section
is provided as a filler to fill any head space or void area that may exist or occur,
for example, due to incomplete filling, settling, or contraction of the contained
material, between the liner bag 100 and the end cap 90. The top pad 102 is particularly
suited for applications in which a liquid is contained as it prevents, or at least
helps to reduce, the harmful sloshing or surging of the liquid which tends to occur
during transit motion. However, the compressibility of the top pad 102 still allows
expansion of the liquid, thereby releasing some of the hydrostatic or hydraulic pressures
which would otherwise be exerted against the sidewalls and bottom of the container.
The top pad 102 is preferably composed of triple wall corrugated fibreboard or polyether
foam. The periphery of the top pad bears against the inner surface of the inner sleeve
12.
[0030] Steel strapping 84 is employed to hold the shipping containers to the pallet 96.
In order to avoid damage to the end cap 90, inverted U-shaped steel strapping braces
86 are mounted across the end cap 90 intermediate of both the upper surface and side
flanges 92 of the end cap and the strapping 84. Each strapping brace 86 consists of
a flattened central elongated plate and depending legs
designed to overlie the top surface and flanges 92, respectively, of the end cap.
The braces 86 are provided with a greater width than the strapping 84 in order to
more evenly distribute the strap forces over the shipping container. The surface of
the strapping brace 86 is preferably beaded in order to inhibit slippage between the
strapping and the brace. When the strapping braces 86 are tightened down by the strapping
84, the inner sleeve 12 is positively seated against the bottom pad 98 to further
stabilize the contained load. The end flaps are held in place by the weight of the
contained materials pressing down on the bottom pad and, in conjuction with the pressure
of the strapping, provide a strengthening or resistance to lateral deflection at the
bottom of the outer sleeve 14, which is the area that is most vulnerable to buckling
or deflection.
[0031] A bottom spout fitment 88, as is known in the bag industry, may be provided. The
fitment 88 extends through cutouts formed in the outer sleeve and the inner sleeve.
The fitment 88 is connected to the liner bag to allow gravity evacuation of the material
contained within the liner bag 100. The fitment extends through apertures formed through
the walls of the inner and outer sleeves.
[0032] Actual containers, built in accordance with the invention, have been subjected to
drop tests, vibration tests and high humidity compression tests with markedly successful
test results. The following examples are illustrative and explanatory of portion of
the invention.
EXAMPLE I
[0033] A shipping container was constructed according to the invention. The outer sleeve
was formed of a triple wall 1500 AAA grade corrugated fibreboard. The outer sleeve
had an octagonal cross section and was approximately 40 inches across and 44 inches
high. The inner sleeve was also formed from triple wall 1500 (Beach puncture test
rating) AAA grade corrugated fibreboard material bent into a circular cylindrical
shape with random scores. Single wall bottom end flaps were employed. An octagonal-shaped
bottom pad formed from 0900 AAA grade corrugated fibreboard and a top end cap of 275#
single wall, fluted fibreboard as utilized to close the ends of the outer sleeve.
A plastic liner bag, filled with 220 gallons of water, was inserted into the container.
A top pad composed of a triple wall 0900 AAA grade corrugated fibreboard having an
octagonal shape was placed on top of the liner bag to substantially fill the void
between the liner bag and the top end cap. Three 3/4-inch x .020 inch size steel strappings
were used to attach the container to a 2-way entry wooden pallet 44 x 44 inches. Two
straps were placed in the same direction and one strap was placed crosswise over the
other two. Each strap was mounted on a five inch wide brace of 16 gauge beaded sheet
metal with three-inch long legs.
[0034] The container was tested using a distribution cycle patterned after ASTM standard
D-4169, distribution cycle no. 11 rail, trailer on flat car to simulate handling,
vertical linear motion, loose-load-rotary motion vibration and rail switching. The
liquid was retained within the liner bag without leakage throughout the entire test
procedure.
(A)
Handling Drop Test
[0035] In the drop test, the container was raised six inches off of a concrete floor by
means of a fork lift and dropped on edge. The test was repeated on the opposite edge.
No leakage occured.
(B)
Vertical Linear Motion Vibration Tests
[0036] The container was subjected to vertical linear motion vibration by placing it on
the table of a vertical linear motion vibration tester having a table displacement
of 1.0 inch. The low and medium vibration emported in vertical linear vibration testing
simulates truck transit conditions and determines whether destructive resonance of
the container will occur. The container was horizontally restained. The c
ontainer was placed on the table and subjected to 260 cpm for 40 minutes. The container
was then placed on an a higher vibration machine, again restrained in the horizontal
direction, and subjected to 40 minutes of vertical linear vibration at the following
frequencies and displacements:

No leakage occured throughout the vertical linear motion vibration testing.
(C)
Loose Load-Rotary Motion Vibration Test
[0037] The container was also placed on a rotary motion vibration machine with a table displacement
of 1.0 inch. The rotary vibration test simulates the side-to-side motion which commonly
occurs in rail transport or piggy back shipments. The container was vibrated for twenty
minutes at a frequency of 235 rpm. It was then rotated ninety degrees and vibrated
for another twenty minutes at 235 rpm. No leakage occured.
(D)
Rail Switching-Incline Impact Test
[0038] The container was placed on the dolly of an incline-impact machine for impact against
a bulkhead to simulate train car bumping. A second container (also filled) was placed
behind the first container. The container was subjected to one impact of 4 mph and
two impacts of 6 mph. No leakage occured.
EXAMPLE II
[0039] A shipping container was constructed according to the invention (as set forth in
Example I) for testing after being subjected to adverse humidity conditions. A plastic
liner bag was filled with 220 gallons of water and inserted into the container.
[0040] The container was conditioned for 72 hours at 90°F and a relative humidity of 90%.
After 72 hours the conditioned container was compression tested to simulate container
stacking. A load was applied by a top platen travelling downwardly at a speed of 0.5
inch per minute until the container failed. Failure did not occur until a load of
8,600 pounds was reached.
EXAMPLE III
[0041] A container constructed as in Example I was conditioned for 72 hours at 73°F and
a relative humidity of 50%. A plastic liner bag was filled with 220 gallons of water
and inserted into the container. A load was applied as set forth in Example II. Failure
of the container did not occur until a load of 18,000 pounds was reached.
[0042] It is a particular feature of the container according to the invention that the inner
sleeve 12 may be filled with a bulk flowable material without bulging. This is due
to the circular cross section of the inner sleeve 12, which transmits the pressure
from the flowable load, purely into hoop stress in the walls of the inner sleeve 12,
inherently resisting any bulging of those walls.
[0043] The outer sleeve 14, due to its construction from a double wall or triple wall corrugated
fibreboard, is adapted to resist endwise crushing loads, permitting a number of such
containers to be stacked one upon the other.
[0044] The enhanced capability of the heavy-duty shipping container to accommodate and withstand
static and cyclic loads is attributable to a structure which utilizes a circular multi-wall
fibreboard inner sleeve and an outer multi-wall fibreboard container against which
the inner sleeve bears. Constructions utilizing solid fibre or single wall (double
face) corrugated fibreboard inner and outer sleeves are not suited to use as heavy-duty
shipping containers and are outside of the scope of the invention.
[0045] The term "heavy duty" is used herein to define containers designed to accommodate
bulk flowable materials in volumes of at least 55 gallons and weights of 450 pounds
and greater.
[0046] The shipping container design described herein, when utilized in conjunction with
a plastic liner bag, is suitable for liquids and dry, flowable products in volumes
of 55 gallons up to 380 gallons, liquid measure. Liquids and suspensions which weigh
as much as 12.5 lbs. per gallon and flowable dry solids which weigh as much a
s 115 lbs. per cubic foot can be effectively contained in fibreboard containers of
this design in those volumes.
1. A heavy-duty shipping container (10) for bulk flowable materials of the type having
an outer sleeve (14) with an octogonal cross section; an inner sleeve (12), having
a substantially circular cross section, substantially coaxially mounted within the
outer sleeve (14); the outer sleeve having a plurality of parallel wall panels (18,
20, 22, 24, 26, 28, 30, 32); and the inner sleeve (12) axially bearing centrally along
each of the wall panels; the inner sleeve (12) being characterized by an inner circumferential
facing with a multiplicity of false scores (75) extending axially along the inner
sleeve (12); and wherein the inner sleeve (12) and outer sleeve (14) each comprise
a triple-wall corrugated fibreboard.
2. A heavy-duty shipping container according to claim 1, wherein the circular inner
sleeve comprises a sheet of triple wall corrugated fibreboard formed by the steps
of passing the sheet through a curved path so as to impart a curvature to the corrugated
sheet to cause the randomly spaced formation of multiple false scores on the inner
circumferential facing of the inner sleeve in the direction of the corrugations, overlapping
edges of the sheet, and adhesively securing the overlapped edges to each other.
3. A heavy-duty shipping container according to claim 1 or 2, wherein the false scores
of the inner sleeve are spaced from one to six inches apart.
4. A heavy-duty shipping container according to claim 3, further comprising a plurality
of end flaps (52, 54, 56, 58, 60, 62, 64, 66), each end flap being foldably connected
to a respective one of the side walls at a first end of the outer sleeve (14), each
of the end flaps comprising a single wall corrugated fibreboard, and each of the end
flaps being folded inwardly of the outer sleeve.
5. A heavy-duty shipping container according to claim 4, further comprising a bottom
pad (98), the bottom pad having a octagonal cross section, and the bottom pad being
mounted on the end flaps intermediate the end flaps and the inner sleeve.
6. A heavy-duty shipping container according to claim 5, wherein the bottom pad (98)
ha a peripheral edge mounted against the wall panels of the outer sleeve (14).
7. A heavy-duty shipping container according to claim 6, wherein the bottom pad (98)
comprises triple wall corrugated fibreboard.
8. A heavy-duty shipping container according to claim 7, further comprising bag means
(100) for containing the flowable materials mounted within and substantially filling
the inner sleeve (12).
9. A heavy-duty shipping container according to claim 8, further comprising a top
pad (102), and an end cap (90) for closing a second end of the outer sleeve (14) opposite
the first end, the top pad having a circular cross section, the top pad being mounted
within the inner sleeve (12) intermediate the bag means (100) and the end cap (90),
and wherein the top pad has a circular periphery in engagement with the inner sleeve.
10. A heavy-duty shipping container according to claim 9, wherein the top pad (102)
comprises a triple wall corrugated fibreboard.
11. A heavy-duty shipping container according to claim 9, wherein the top pad (102)
comprises a compressible polyether foam.
12. A heavy-duty shipping container according to claim 9, wherein the end cap (96)
has a cross section similar to the cross section of the outer sleeve (14), the end
cap having peripheral side flanges which overlie the side wall of the outer sleeve
and further comprising a plurality of inverted U-shaped braces (86) mounted to the
end cap (90), each brace (86) including a central portion overlying the end cap intermediate
the flanges of the end cap and depending legs overlying opposite flanges of the end
cap, a pallet (96), and strap means (84) overly
ing the braces for holding the container to the pallet.