Palletized container

A reusable plastic base serves as a pallet which may be lifted by the skids of a forklift truck. A sleeve is removably attached to the base and forms the side walls of the container. In the preferred embodiment, the sleeve is made of corrugated material having tabs formed along its lower edge. The tabs are adapted to pass through slots in the base and be folded underneath the base to hold the components together. The base is preferably designed with a peripheral groove lying substantially at floor level to receive the edge of the sleeve. Compressive loads applied to the container are transferred by the sleeve directly to the floor thereby minimizing deformation of peripheral portions of the base.

TECHNICAL FIELD 
This invention relates to shipping and storage containers. More 
particularly, it relates to containers in which the base thereof serves as 
a reusable pallet. 
BACKGROUND ART 
Various container designs have been employed to ship and store industrial 
goods. In many instances the containers are stored in large warehouse 
facilities where they are moved from one location to another by forklift 
trucks or the like. One commonly used container incorporates a corrugated 
sleeve which is nailed to a conventional wooden pallet. The sleeve forms 
the side walls of the container and the pallet serves as its bottom. The 
use of the wooden pallets, however, has some drawbacks. For example, they 
are subject to be broken and thus, are not reuseable over an extended 
period of time. Wooden pallets also taken up a considerable amount of 
valuable floor space in the warehouse when they are not currently in use. 
In an effort to solve some of the problems with the wooden pallets, 
reusable plastic pallets have been employed with some degree of success. 
Such pallets have been combined with corrugated sides and a plastic cover 
to form a container. The plastic pallet and cover are reusable and may be 
more compactly stacked when not in use thereby providing significant 
advantages over the use of conventional wooden pallets. U.S. Pat. No. 
4,254,873 to Cook, III et al is a representative example of such a 
composite container design. 
These composite container designs also have their drawbacks. The edges of 
the sleeve merely rest in grooves in the pallet and cover in most of the 
known designs. Consequently, some additional means must be provided to 
hold them together prior to shipping. Generally, the pallet, corrugated 
sleeve and cover are banded together by steel bands or cords encircling 
the three components. This banding process introduces an additional 
expense in both time and money since the container must not only be bound 
prior to shipping but it also must be unbound before the container's 
contents can be removed. 
As noted before, warehouse space is valuable. It is therefore desirable to 
be able to stack these composite containers on top of one another in order 
to conserve space. In such instances the lower containers often experience 
substantial compressive forces from the weight of the upper containers. 
These compressive forces are generally transferred by the sides of the 
container downwardly to the peripheral edges of the pallet. In the 
majority of the known plastic pallets, legs or spacers providing clearance 
for the skids of the forklift are spaced inwardly of the peripheral edges 
of the pallet experiencing the compressive loads. The drawing labeled 
"Prior Art" shows a simplified cross-sectional view of a corner of such a 
construction. As shown in the dotted lines therein, the compressive loads 
applied via sleeve A are often sufficient enough to deform the peripheral 
portions of the pallet outside of the leg B which rests on the supporting 
surface such as the floor. Such deformation may damage the pallet to such 
an extent that it is not readily reusable. The structural rigidity of 
these pallets may be enhanced by using more plastic material or by using 
special reinforcing means but such measures unduly increase manufacturing 
costs. 
The present invention is directed to solving one or more of these problems. 
SUMMARY OF THE INVENTION 
There are several inventive features disclosed in this patent which may be 
used alone or in combination. One feature is the provision of a container 
employing a base and a removable sleeve providing side walls for the 
container. The sleeve includes a plurality of tabs formed at spaced points 
along its edge. These tabs are aligned with slots formed in peripheral 
portions of the base. The tabs are adapted to pass through the slots and 
be folded underneath the base to securely hold the sleeve on the base. In 
the preferred embodiment, the base is made of plastic and the sleeve is 
made of corrugated material. The base is also formed with indentations 
which serve to receive the skids of a forklift or the like so that the 
base may function as a pallet. 
A cover may optionally be provided for the container. The cover is 
preferably a mirror image of the base and is removably attached to the 
sleeve in an identical manner. 
Another feature of this invention is that the base includes means lying in 
substantially the same plane as the bottom surface of the base for 
receiving the lower edges of the sleeve. The skid receiving indentations 
in the base are located inboard and above at least the corner edges of the 
sleeve. Accordingly, downward compressive loads applied to the container 
are transferred by the sleeve substantially directly to the supporting 
surface thereby minimizing deformation of peripheral portions of the base. 
Another feature is the design of the sleeve for use with the pallet.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
FIGS. 1 and 2 illustrate a container 10 made in accordance with the 
preferred embodiment of this invention. Container 10 is of a composite 
design employing a sleeve 12 removably attached to a base 14 and cover 16. 
Sleeve 12 takes the form of an open ended rectangular box providing side 
walls 18, 20, 22 and 24 for the container 10. In this embodiment, sleeve 
12 is formed of three ply panels of corrugated material such as is 
commercially available from Tri-Wall Containers, Inc. Corrugated material 
for sleeve 12 is preferred because it is relatively inexpensive, is easy 
to form foldable tabs therein as will be explained, and can be collapsed 
when not in use. At the same time, the preferred corrugated sleeve 
exhibits comparatively good strength characteristics. However, it should 
be understood that various other suitable materials could be used for 
sleeve 12. 
The top edge 26 and bottom edge 28 of sleeve 12 each include a plurality of 
spaced pairs of tabs 30, 30' and 32, 32', respectively. These tabs are 
conveniently formed by cutting the corrugated sleeve along a horizontal 
line 34 and cutting a vertical notch 36 therein. The tabs are thus capable 
of being folded horizontally about fold line 38. As can be seen most 
clearly in FIGS. 1 and 9-11, the tabs are adapted to be folded at about a 
90 degree angle towards the middle of the container 10 to thereby securely 
attach sleeve 12 to the base 14 and cover 16. 
In the preferred embodiment, base 14 and cover 16 are mirror images of one 
another. In other words, they are identical except that the cover 16 has 
been flipped over 180 degrees with respect to the base 14. Base and cover 
14 are preferably made of plastic and thus, the same mold may be used to 
make both of the structures. In this embodiment, the base and cover are 
made by vacuum forming sheets of organic polymeric material such as 
polyethylene. They are both made of a twin sheet construction employing 
two skins which are fused or knitted together at various points to aid in 
structural rigidity. However, it should be noted that various plastic 
materials and other formation techniques such as injection molding, 
rotocasting and the like may be alternately employed. 
Since the base 14 and the cover 16 are identical and same reference 
numerals will be used to refer to common elements. For ease of description 
some of these elements will be described in connection with the base 14 
whereas others will be described in connection with the cover 16. For 
example, it is easier to describe the tab attachment arrangement with 
respect to the cover 16 due to the layout of the drawings. However, it 
should be understood that the same construction is employed in the base 
14. 
Beginning then with reference to base 14, it is provided with an flat lower 
or outer face 40 configured so that at least the corners thereof lie on 
the supporting surface such as the floor for the container. A plurality of 
elongated indentations 42-48 displaced from the plane of face 40 criss 
cross in the middle of base 14 and terminate on the sides thereof. As can 
be seen most clearly in FIG. 1, these indentations 42-48 provide relieved 
access areas for receiving the skids 50 of a forklift truck or the like. 
As a consequence, the base 14 may serve as a pallet for the container 10 
which may be lifted and moved by conventional warehousing equipment. 
Peripheral portions of the upper or inner face 52 of base 40 are provided 
with a groove 54 for receiving the edges of sleeve 12. It is important to 
note that the bottom of groove 54 extends downwardly substantially the 
same level as outer face 40 as can be seen most clearly in FIG. 4. This 
allows the bottom edge 28 of sleeve 12 to terminate substantially at 
ground level. This is in contrast with the prior art design shown in the 
drawing where the edge of the sleeve A terminates above floor level 
because of the design of leg B. In the present design compressive forces 
applied downwardly to the container 10 are transferred via the sleeve 12 
substantially directly to the floor or other supporting surface. As a 
consequence, the deformation problem associated with the shown prior art 
design is effectively eliminated without a substantial increase in 
manufacturing costs. 
The sides of the skid indentations 42-48 form the tab attachment sections 
generally noted by the reference numeral 60. This feature of the present 
invention will be described in connection with cover 16. However, it again 
should be emphasized that the same construction is used in the base 14. 
Tab attachment section 60 includes a pair of transverse slots 62, 62' which 
are adapted to receive tabs 30, 30' respectively, in an unfolded condition 
as can be seen most clearly in FIG. 9. Slots 62, 62' extend transversely 
through the outer face 40 to the inner face 52 of cover 16. The slots lie 
in generally the same vertical plane defined by adjacent portions of 
peripheral groove 54. Slots 62 and 62' are divided by a bridge portion 64 
to give the construction added rigidity. Notch 36 in each of the tab pairs 
provide clearance for bridge 64. 
It will be appreciated that it will not always be possible to maintain the 
tabs in their perfect coplanar alignment with their associated walls of 
the sleeve 12 as shown in FIG. 2. After a period of use it is expected 
that the tabs will have a tendency to point inwardly about their 
respective fold lines 38 when the container is disassembled. Accordingly, 
it may become a burdensome task to manually align all of the tab pairs so 
that they easily pass through their respective slots in the cover 16 and 
base 14 when the container is assembled. It would also be desirable to 
maintain the flaps coplanar with their respective slots when the container 
is disassembled so that the cover and base may be easily lifted from the 
sleeve without catching one or more of the tabs which may have a tendency 
to retain their folded angular orientation. These potential problems are 
overcome by way of the aspect of the present invention which will now be 
described. 
With particular reference to FIG. 6, the inner face 52 defining the tab 
attachment section 60 includes a ramp 70. Ramp 70 (which can also be seen 
in FIG. 2) is inclined at an angle which slopes toward the slots 62, 62'. 
Ramp 70 cooperates with inner portions of a vertical side flange 72 to 
form a v-shaped chute converging towards slots 62, 62'. 
FIG. 6 shows in solid lines a tab 30 which has been bent. When the cover 16 
is brought downwardly so that the tabs enter the chute, the bent tab 
engages the inclined ramp 70 which straightens it out and guides it 
through its respective slot as shown by the dotted lines. The camming 
action provided by way of ramp 70 thus enables the base 14 and cover 16 to 
be easily fitted on the edges of the sleeve 12 even though some of the 
tabs may have been bent. 
FIGS. 8 and 9 illustrate the initial position of the tabs once they pass 
through their respective slots with the top edge 26 of the sleeve 12 
abutting peripheral groove 54. With additional reference to FIGS. 3, 5 and 
7, tab attachment section 60 further includes a channel 78 in face 40 
extending orthogonally in the horizontal plane from each of the slots 
beginning at the point where the fold lines 38 of the tabs are located; 
i.e. the intersection of the channels with their respective slots. A wedge 
shaped camming surface 80 is provided between each of the channel-slot 
intersectiona in face 40. The camming surface slopes toward the 
intersection of the channels and slots so that the point of the wedge is 
substantially in the same plane as the cut line 34 defining the bottom 
edge of each tab. The sides of the camming surface 80 define upstanding 
shoulders 82 and 84. Shoulder 84 provides one side wall for channel 78. 
As shown in FIG. 10 the tabs are folded by lifting the distal end thereof 
up over shoulder 82 and bending the tab about fold line 38 until the 
bottom edge thereof traverses over camming surface 80 and is received 
within the pocket defined by channel 78. As shown in FIG. 11, the channel 
78 holds the tabs securely in place since the shoulder 84 prevents the tab 
from returning to its original position. 
When this tab attachment procedure has been performed for the base 14 it 
will be noted that the tabs 32 are folded underneath the base and thus 
securely lock the sleeve 12 thereon. The goods then may be placed within 
the interior of the container without fear of the sleeve shifting or 
falling off the base. After the goods have been placed within the open 
container then the cover 16 may be assembled to the sleeve 12 as noted 
above. It should be understood that in some applications it may not be 
necessary to provide a cover for the container and thus cover 16 may be 
eliminated. 
To disassemble the base and cover from the sleeve, the procedure noted 
above is merely reversed. Briefly, the distal ends of the tabs are lifted 
to clear shoulder 84 and then folded over camming surface 80 until they 
become aligned with their respective wall portions of the sleeve 12. Note 
that the flange 72 extends beyond the bottom cut line 34 of the tabs to 
provide a stop for preventing the tabs from being swung outwardly too far 
as shown most clearly in FIG. 8. The shoulder 82 analogously prevents the 
tabs from returning to their folded condition toward the middle of the 
container. Thus, once the tabs are swung outwardly they drop down within 
the confines of flange 72 and shoulder 82 thereby maintaining them in 
alignment with their respective wall portions. Accordingly, the base or 
cover may be lifted from the sleeve with the tabs easily passing through 
their respective slots without interference. 
Those skilled in the art will appreciate that the design of the present 
invention offers significant advantages over previous composite container 
designs. Among the advantages is the elimination of the requirement of 
banding the components together. In contrast, the container of the present 
invention may be assembled or disassembled quite easily without 
necessitating external apparatus. The containers when assembled are 
stackable on top of one another due to their durable design. It may be 
advantageous to employ some sort of interlocking structure on the bottom 
of the base and top of the cover to prevent lateral slippage of the 
stacked containers. However, this is well within the skill of the ordinary 
practitioner. By bringing the sleeve substantially to the floor level the 
container can withstand substantial compressive loads without having to 
use substantial amounts of plastic or additional reinforcing means when 
forming the base to counteract such loads. When the container is 
disassembled the base and cover may be easily stacked and nested within 
one another in a compact manner ready for use. The sleeve, likewise, may 
be collapsed and neatly stored when not in use. On the other hand, the 
relatively inexpensive corrugated sleeve material may just be thrown away 
if desired after a period of time. Still other advantages and 
modifications of the preferred embodiment of the invention will become 
apparent to those skilled in the art upon a study of the specification, 
drawings and claims.