Note: Descriptions are shown in the official language in which they were submitted.
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BACKGROUND OF T~IE INVENTION
This invention relates to pallets, and in particular to
inexpensive and lightweight pallets.
The pallets of the present invention preferably are
constructed of corrugated cardboard, however, it will be
appreciated that they may be constructed of other simular types
of materials such as solid fibreboard or pasted chipboard.
Prior art pallets have employed flat corrugated pallet decks
to which a plurality of leg members are attached. The pallet
deck is supported above its resting surface so that the pallet
and its contents may be picked up by mechanized equipment such as
a forklift truck.
Prior art corrugated pallets have utilized a simple and
effective attachment means by which a tubular cardboard leg,
usually constructed of spiral laminated paperboard material, is
attached to the pallet deck by gluing. To effect a strong
attachment, the prior art corrugated pallets have utilized a
sunburst-shaped pattern which is die-cut in the corrugated pallet
deck at each leg attachment point. The die-cut pattern utilizes
a central hole with radiating die cuts terminating at an outer
radius corresponding to the inner diameter of the pallet leg.
The finger members thus formed are generally referred to as
straight finger members and have blunt tips where they originate
from the central hole.
After cutting, the straight finger members are forced
downward into an annulus between two nested tubular leg elements.
Glue is applied to the finger elements prior to being forced
downward into the annulus to fixedly secure the finger elements
within the annulus, and hence the pallet leg to the pallet deck.
Pallets having pallet legs attached thereto in the manner
described are disclosed in U.S. patents 2,665,807; 3,052,397;
3,266,444 and French patent 1,470,774.
An improvement of the above-described pallet and method o
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attaching pallet legs thereto is disclosed in United States Patent
No. 4,487,136 issued December 11, 1984. As disclosed therein, the
finger elements are formed by die-cut lines tangent to a central
hole so that a somewhat spiral pattern is formed, much like a
camera iris. The resulting finger members are generally referred
to as spiral finger elements, as opposed to the straight finger
elements. These spiral finger elements, according to various test
results, provide a pallet leg which is far stronger and less
subject to damage when a sideways force parallel to the pallet
deck member is applied to the pallet leg.
The pallets disclosed in the above-identified U.S. patents,
in many cases, have another corrugated cardboard pallet deck
member adhesively affixed atop the pallet deck to which the pallet
legs are affixed in order to provide additional strength to the
pallet. The pallet per se is strengthened in this fashion, but
the added pallet deck member does not strengthen to any
substantial degree the pallet leg against damage from sideway
forces applied to them.
While the pallets of the above-identified type are generally
satisfactory, there is still a desire for an inexpensive and
lightweight pallet of corrugated cardboard which has both greater
deck strength and pallet legs which are not as susceptible to
damage when a sideways force is applied to them. The deck
strength can be increased by adhesively affixing another pallet
deck member atop the pallet deck as described above, but this
method of increasing the deck strength suffers from the expense
and difficulties associated with adhesively affixing the other
pallet deck member to the pallet. For example, adhesive must be
applied to one or surfaces of the two pallet deck members, the two
deck members properly aligned atop one another, and then clamped
until the adhesive sets. These requirements all add to the cost
of the pallets.
Also, for the purpose of storing and shipping these standard
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pallets, the pallets normally are stacked atop one another to a
height of 84". The four corners of the stacked pallets are
protected with creased corrugated cardboard dimensioned to extend
the 84" height of the stack and 6 inches on each side of the
stack about the corners. The stacked pallets then are stretch
wrapped or banded. The need to provide the corner protectors
likewise adds to the cost of the pallets.
Accordingly, it is an object of the present invention to
overcome the above as well as other disadvantages of these prior
art pallet designs, and to provide an improved inexpensive and
lightweight pallet having both a greater deck strength and pallet
legs having greater strength against sideways force applied to
them.
Further still, it is an object to provide such an improved
pallet which is far simpler to manufacture.
A still further object is to provide such an improved pallet
which is far simpler and less expensive to stack for storage and
shipment.
The above as well as other objects not specifically
mentioned are accomplished by providing a pallet having a pallet
deck which is formed from at least two pallet deck members, each
of which has finger elements die-cut therein at each leg
attachment point. The pallet deck members may be of solid
fibreboard, pasted chipboard and other like materials, however,
it is preferred to use corrugated cardboard since this material
is lightweight and the most inexpensive. The pallet legs are
formed from tubular outer and inner leg elements, and are
attached to both pallet deck members by stacking them atop one
another and forcibly urging the finger eiements on both pallet
deck members within the annulus between the nested outer and
inner leg elements. With this construction, the pallet deck is
increased in strength since two pallet deck members are utilized
and the pallet legs have greater strength and are less subject to
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damage from sideways forces parallel to the pallet applied to
them since they are attached to the pallet by the finger elements
die-cut in both of the pallet deck members.
Pallets constructed in this fashion also are far easier to
assemble. The finger elements are die-cut into each of the
pallet deck members by the same die, and therefore are in perfect
alignment when the two deck members are stacked atop one another.
Also, it is not necessary to adhesively affix the two deck
members to one another, since the tubular leg elements
effectively function like rivets to secure the deck members
together. Preferably, however, some adhesive is applied to the
mating surfaces of the deck members. Even though some adhesive is
used, a substantial advantage is still provided, since the
tubular leg elements function to secure the deck members together
until the adhesive sets, thus the need to clamp them together as
in the past is eliminated.
A multiple number of pallet deck members can be stacked atop
one another to form the pallet deck and when corrugated cardboard
is used each pallet deck member can be single wall, double wall
or thicker corrugated cardboard or any combination thereof.
However, in a preferred embodiment, only two pallet deck members
are used, and each of them is a double wall corrugated cardboard.
The double wall deck members are die-cut and assembled as
described above, and provide a pallet which is both economical
and sufficiently strong for most applications. The inner leg
elements preferably are of a length to substantially cover the
finger elements when assembled to form the pallet legs. The
pallet legs can be reinforced for both load capacity and abrasive
wear by using an inner leg element which is of substantially the
same height, or length, as the outer leg element. A pallet leg
of this construction also can be used on a standard pallet which
has a pallet deck formed of one single wall corrugated cardboard
deck member, but the single wall corrugated deck member does not
have sufficient strength and the pallet leg under extremely rough
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use can be torn off. Accordingly, there is little benefit in
reinforcing the pallet legs on a standard pallet in this fashion,
if the pallet is to be subjected to extremely rough use.
In accordance with the invention, it is also preferred to
cross laminate the corrugated cardboard deck members, i.e., the
corrugations of the deck members extend perpendicular to each
other. Such cross laminating of the deck members substantially
increases the deck strength of the pallet. Further still,
according to the invention, a substantial improvement in the
strength of the pallet legs is provided whether straight or
spiral finger elements are used, when the finger elements die-cut
in both pallet deck members are captured between the nested outer
and inner legs elements. Again, however, it is preferred to use
spiral finger elements, since they provide several advantages not
provided by the straight finger elements. In particular, the
spiral finger elements are much stronger and therefore provide a
pallet leg which is much stronger and more resistant to sideways
forces applied to them. In adddition, the spiral fingers are
longer in length than the straight fingers. Accordingly, when
the multiple corrugated cardboard deck members are used, the
spiral finger elements when forced downwardly into the annulus
between the two nested outer and inner leg elements forming the
pallet legs provide a longer and hence more finger surface area
which is affixed together to one another and to the walls of the
leg elements.
Also, according to the invention, it is preferred that the
spiral finger elements on each of the pallet deck members
substantially fully overlap each other. Also, the score lines
defining the outer periphery of the finger elements should
project downwardly on both pallet deck members when stacked atop
. .
one another. In order to achieve this arrangement, one pallet
deck member is run through the die-cutting machine with its
corrugations running in one direction and the other pallet deck
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member is run through with its corrugations running perpendicular
to the first deck member. Effectively, a top and a bottom pallet
deck member are die cut, but it makes no difference which is the
top, or the bottom, deck member. When die-cut in this fashion
and stacked atop one another with a cross lamination, the finger
elements when forced downwardly into the annulus between the
nested outer and inner leg elements will substantially fully
overlap each other. The overlapped spiral finger elements
~ .... .
provide pailet legs which have far greater strength, particularly
against sideways forces applied against them.
It is also possible to die-cut the pallet deck members as
described above,and to then flip over one pallet deck member and
stack it atop the other. In this instance, however, when the
finger elements are forced downwardly into the annulus between
the outer and inner leg elements, the spiral finger elements of
one deck member project radially in one direction and those on
the other deck member project radially in the opposite direction
so that there is a radial overlapping of the finger elements.
While assembling the pallet deck members in this fashion provides
an increase in the strength of the pallet legs, the increase is
not as great as it is when the finger elements substantially
fully overlap each other.
Pallets constructed in accordance with the present invention
provide still another advantage over the standard pallets when
stacking the pallets for storage or shipment. As indicated
above, the pallets normally are stacked atop one another to a
height of 89" and prior to banding or stretch wrapping the
stacked pallets, the four corners of the stacked pallets are
protected with corrugated cardboard corner protectors. Since the
deck members of the pallets of the present invention are much
stronger than the standard pallets, it is found that the normally
used corrugated cardboard corner protectors can be eliminated.
Also, the pallets can be secured in the stacked relationship
simply by banding them together by extending a band through the
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holes of the pallet legs. In each instance, a substantial cost
savings is provided.
A lightweight and inexpencive pallet having exceptional beam
strength for supporting and transporting heavy loads, by means of
forklift trucks and automated mechanical load handling conveying
or transporting equipment, can be provided by adding a second
pallet deck to the underside of the pallet. More specifically,
according to the invention, a second pallet deck is secured to
the pallet by attaching the second pailet deck to the bottom of
the pallet legs in the same fashion as the pallet deck is
attached to the top of the pallet legs. The pallet legs thus are
effectively sandwiched between the two pallet decks. With this
construction, a rigid pallet having a substantially greater beam
strength, i.e., less tendency to flex in the longitudinal plane
thereof, is provided. The beam strength also can be increased by
affixing parallel strips, as opposed to a fully pallet deck, to
the pallet legs. Further still, the beam strength can be
increased by extending one length of the pallet deck such that
the pallet deck can be folded essentially U-shaped along two
opposing edges thereof and affixed to the pallet legs.
Other objects and advantages of the invention will become
apparent from the following detailed description and upon
reference to the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a perspective view of a pallet exemplary of the
invention;
Fig. 2 is a partial bottom plan view of the pallet of Fig.
1, partially sectionalized to illustrate the cross lamination of
the pallet deck members;
Fig. 3 is an enlarged sectional view taken along lines 3-3
of Fig.2;
Fig. 4 is a partial top plan view of one of the pallet deck
members illustrating the straight finger elements die cut therein
13~3~88
at a leg attachment point;
Fig. 5 is a view like Fig.4 only illustrating the spiral
fingers die cut in a pallet deck member at a leg attachment
point;
Fig. 6 is a partial perspective view, with the outer leg
element removed, illustrating the manner in which the straight
finger elements overlap when disposed within the annulus between
the outer and inner leg elements;
Fig. 7 is a view like Fig. 6 illustrating the manner in
which the spiral fingers overlap in accordance with a preferred
embodiment;
Fig. 8 is also a view like Figs. 6 and 7 illustrating an
alternative manner in which the spiral fingers can be overlapped;
Figs. 9 and 10 are partial side sectional views
illustrating the longer spiral finger elements and the shorter
straight finger elements, respectively; and
Fig. 11 is a side plan view illustrating how the pallets
can be stacked for storage an shipping.
Fig. 12 is a perspective view of a pallet having a second
pallet deck affixed to it to provide improved beam strength;
Fig. 13 is a sectional view taken along lines 13-13 of Fig.
12, and
Fig. 14 and 15 are side plan views of pallets illustrating
alternative methods of improving beam strength.
DESCRIPTION OF THE PREFERRED EMBODIMENT
_
Referring now to the drawings, in Fig 1 there is illustrated
a pallet 10 having four pallet legs 12 affixed thereto to the
underside thereof. While only four pallet legs 12 are shown, it
is apparent that any number of pallet legs can be affixed to the
pallet. The pallet 10 includes a pallet deck 14 which is
constructed of multiple (two as illustrated) pallet deck members
16 and 18 which are of the same dimensions and are stacked atop
1323588
one another, as more specifically described beiow. As indicated
above, the pallet deck members 16 and 18 may be of solid
fibreboard, pasted chipboard and other like materials, but
preferably they are of a corrugated cardboard material. The
pallet legs 12 each is formed of an outer leg element 20 which is
dimensioned to receive therein an inner leg element 22, with the
finger elements 24 which are die-cut in the respective ones of
the pallet deck memebers 16 and 18 at the leg attachment points
compressed and retained within the annulus 28 between the nested
outer and inner leg elements 20 and 22, as illustrated in Fig. 3.
The outer and inner leg elements 20, 22 may be laminated paper
tubular elements.
The finger elements 24 die-cut in the respective ones of the
pallet deck members 16 and 18 may be straight finger elements as
illustrated in Fig. 4, or spiral finger elements, as illustrated
in Fig. 5. More specifically, the straight finger elements of
Fig. 4 are die-cut in a sunburst-shaped pattern and utilize a
central hole 30 with radiating die cuts 32 terminating at an
outer radius or score line 34 having a diameter corresponding to
the inner diameter of the pallet leg 12. The finger elements 24
thus formed have blunt tips where they originate from the central
hole 30. The spiral finger elements of Fig. 5 are formed in
substantially the same fashion, however, the die-cuts 32 radiate
outwardly tangentially from the central hole 30 so as to provide
a spiral or iris-like pattern. In forming the pallet 10 either
straight finger elements or spiral finger elements can be used.
In either case, a substantially stronger pallet which is far
easier to assemble is provided, as more specifically set forth
below. However, a preferred embodiment includes spiral finger
elements since such type finger elements provide pallet legs
which are much stronger and more resistant to sideways forces
parallel to the pallet deck 14 applied to them.
The pallet deck 14, as indicated above, may be formed of
multiple pallet deck members and these pallet deck members may be
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corrugated cardboard which is single wail, double wail, triwall
or any combination thereof. However, a pallet deck 14 formed of
at least two double wall corrugated cardboard pallet deck members
16 and 18, as illustrated, has been found to be satisfactory in
most applications and is preferred except in those appiications
where the pallet 10 may be subjected to unusual rough treatment.
Furthermore, the multiple pallet deck members preferably are
stacked atop one another with the corrugations 46 thereof cross
laminated, as illustrated in Fig. 2.
In assembling the pallet 10, the outer leg elements 20 are
placed beneath the two stacked pallet deck members 16 and 18, and
aligned with the respective circular score lines 34. Prior to
stacking the pallet deck members 16 and 18, adhesive is applied
over the finger elements 24 and the area immediately surrounding
them on and preferably at least about the mating surfaces of the
pallet deck members 16 and 18 adjacent the peripherial edges
thereof. The inner leg e~ements 22 are aligned with the circular
score lines 34 on top of the stacked pallet deck members 16 and
18, and then forcibly urged downwardly into the outer leg
elements 20 while at the same time forcing the finger elements 24
of the respective ones of the pallet deck members 16 and 18 into
the annulus 28 between the two nested outer and inner leg
elements. The pallet legs 12 when attached to the pallet 10
effectively function like rivets to secure the two pallet deck
members 16 and 18 together, hence the need to apply adhesive to
the mating surfaces thereof and to clamp them together until the
adhesive sets is eliminated. As indicated above, it is preferred
to apply adhesive to the pallet deck members adjacent the
peripheral edges thereofl but the pallet deck members 16 and 18
are fixedly secured to one another whether such adhesive is used
or not. This feature of the improved pailet 10 provides
substantial savings in both material costs and labor in handling,
as well as the time involved in waiting for the adhesive to set,
` 1323~88
whether the pailet deck members 16 and 18 are single waii, doubie
wall or other type of corrugated cardboard. Even when single
wall pallet deck members 16 and 18 are used, a pallet 10 which is
substantially stronger both with respect to deck strength and
pallet leg strength is provided. A conventional pallet having a
single wall corrugated cardboard deck member, with another single
wall corrugated cardboard deck member adhesively affixed atop of
it is not as strong as the pallet 10 of the present invention,
since the pallet legs are attached to only the one single wall
pallet deck member. As indicated above, the preferred
construction of the pallet 10 has at least double wall corrugated
cardboard pal~et deck members 16 and 18, since they provide a
pallet lO which has far greater deck strength and leg strength.
~Also, while such pallets lO whether formed of single wall or
double wall corrugated cardboard pallet deck members display
greater strength if straight finger elements are used, again it
is preferred to use spiral finger elements because of the gredter
strength of the pallet legs against sideways forces parallel to
the pallet deck applied to them.
In stacking the pallet deck members 16 and 18 atop one
another, it is preferred that they are stacked such that the
circular score lines 30 defining the periphery of the finger
elements both project toward the bottom of the pallet lO. It has
been found that this arrangement provides greater leg strength.
Also, as indicated above, it is preferred that the corrugations
of the pallet deck members be cross-laminated when assembled. In
this respect, when using spiral fingers, it is preferred to run
one pallet deck member through the die-cutting machine with the
corrugations running longitudinally of the machine, and to then
run the other pallet deck member with its corrugations running
perpendicular to the longitudinal axis of the machine so as to
effectively die-cut a top and a bottom pallet deck member. As a
practical matter, however, it makes no difference which pallet
deck member is the top or the bottom one. The pallet deck
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13235~8
members 16 and 18 preferabiy are die-cut in this fashion and then
stacked atop one another with the circular score lines 30 facing
downwardly. With this arrangement, when the pallet legs 12 are
affixed to the pallet deck members 16 and 18, the finger elements
24 of the respective pallet deck members substantially completely
overlie one another within the annulus 28 between the outer and
inner leg elements 20, 22, as illustrated in Fig. 7. The finger
elements are effectively adhesively secured to each other over
substantially the entire surface area of the respective finger
elements and to the walls of the outer and inner leg elements 20
and 22. It is found that this arrangement provides pallet legs
which provide the greatest resistence to sideways forces applied
to them.
The pallet deck members 16 and 18 can be die-cut as
described above and then one flipped over atop the other prior to
affixing the pallet leg 12 to them. When assembled in this
fashion, the finger elements when urged into the annulus between
the outer and inner leg elements 20 and 22 will radially overlap,
as illustrated in Fig. 8. This arrangement provides a
satisfactory pallet 10 having improved leg strength, but the leg
strength of the pallets 10 having finger elements which overlap
as illustrated in Fig. 7 is greater yet and thus preferred.
The straight finger elements, of course, so long as the
pallet deck members 16 and 18 are die cut with the sarne dies
always overlap as illustrated in Fig. 6.
While the straight finger elements provide a satisfactory
pallet 10, it is preferred to use spiral finger elements for at
least several reasons. As indicated above, independent tests
have shown that pallet legs when attached to the pallet deck with
spiral fingers are much stronger and resistant to damage from
sideways forces applied to them then the straight finger
elements. Futhermore, as generaily illustrated in Figs. 9 and
10, the spiral finger elernents are longer and project further
12
1323~8
into the annulus between the outer and inner leg elements than
the straight finger elements. Accordingly, when multiple pallet
deck members are used, more of the finger elements are available
to be retained within the annulus between the outer and inner leg
elements when the finger elements are folded over atop one
another and forced into the annulus. Therefore, there is more
surface area of the finger elements to adhesively secured
together and to the walls of the leg elements.
As indicated above, the pallets 10 are stacked one atop the
other for storage and shipment, generally in the manner
illustrated in Fig. 11. In this case, however, since the pallet
decks 14 are much stronger the corner protectors normally used
with the standard pallets can be eliminated. Accordingly, a
substantial savings in material can be realized. Furthermore,
the stacked pallets normally are band-wrapped to secure them in
stacked relationship one atop the other. With the pallets 10 of
the present invention, this is easily accomplished by extending
the bands through the holes in the pallet legs 12, as
illustrated, making banding thereof much easier. The pallets 10
then can be shrink-wrapped, if desired.
A pallet 50 having exceptional beam strength for supporting
and transporting heavy loads is illustrated in Fig.12 & 13. As
can be seen, the pallet 50 has a top pallet deck 52 and a bottom
pallet deck 59, both of which are affixed to a number to pallet
legs 56 in the same fashion as the pallet deck 19 of the pallet
10 is affixed to the pallet legs 12 thereof. More specifically,
the pallet deck members 58 and 60 forming the pallet deck 54 are
die cut to form finger elements, and the latter are forcibly
urged into the annulus between the nested outer and inner leg
elements forming a pallet leg 56. In this case, a second inner
leg element is required and is nested in the same outer ieg
element used in attaching the top pallet deck 52 to a pallet leg
56. The second pallet deck 59 adds substantial rigidity to the
pallet 50 and greatly increases its beam strength so that it is
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" 1323~8
iess likely to bend or flex in i~s longitudinal plane.
In Fig. 14 there is illus~rated still another pallet 70
which is similar to the pallet 50, but in this case instead of a
full second pallet deck only strips 72 are die-cut with finger
elements and affixed to the pallet legs 74, as illustrated.
Another pallet 80 is illustrated in Fig. 15 having the one
length of the pallet deck 82 extended and folded generally U-
shaped around the opposed sides of the pallet and affixed to the
pallet legs 84. The beam strength of both of the pallet 70 and
80 is increased, but not to the extent that it is increased when
a full pallet deck is used, as illustrated in Figs. 12 and 13.
Also, with the pallet 80, entry for forklift trucks is only
provided or possible from two sides of the pallet.
Accordingly, from the above description it can be seen that
a pallet 10 which can be easily manufactured and assembled, and
particularly one which is light weight and inexpensive, is
provided by the present invention. More particularly still, the
pallet 10 has far greater deck strength and pallet legs which are
much stronger and more resistant to damage from sideways forces
parallel to the pallet deck applied to them than those known in
the prior art or disclosed in the above identified copending
application. The pallets 10 also can be easily stacked for
shipment and storage.
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