Corrugated pallet leg and method

There is disclosed an improved corrugated pallet having pallet legs attached at various points of attachment. The field of invention relates to a corrugated cardboard pallet of the type generally formed by a pair or more of pallet decks which are stacked atop one another, each of which has finger elements die cut therein radiating outwardly from a central circle and terminating on a circular score line of substantially the same diameter as the inner diameter of one of the leg elements. The die cut lines for the fingers radiate tangentially outwardly to create a substantially spiral pattern. The leg assembly is of the type formed by an outer leg, and an inner leg, with the radiating die cut fingers nested between the annulus created between the outer and inner leg and adhesively secured to the legs. The improvement consists of die cutting a series of linearly aligned perforations along the length of each finger, such that when the adhesive is applied to the outer and inner surfaces of the fingers, the adhesive is permitted to permeate the inner confines of the corrugated material forming the fingers thereby increasing the surface area of adhesive for securing the finger elements to the respective leg elements.

BACKGROUND OF THE INVENTION 
The present invention relates to corrugated pallets and in particular to 
the type of corrugated pallets which have been developed for the purpose 
of providing inexpensive and light weight pallets constructed of 
corrugated cardboard. 
Pallets are of course widely utilized in all industries for the purpose of 
stacking and transporting various goods. It is well-known that in the 
past, pallets were formed of wood, in order to lend rigidity and strength 
to the pallet so that merchandise of great weight could be stacked and 
transported on the pallets. However, with the advent of conservation, and 
preservation of the natural resources, the use of woods for constructing 
pallets has been deemed to be undesirable, and even more important, it has 
now been determined by many countries in the world that wood is a nesting 
place for various types of bacteria and other undesirable germs, 
especially when the wood is wet or rotted. Just as importantly, it has 
been found in many countries that pest infestation has become a widespread 
problem, and it has been found that wood pallets have a tendency to 
introduce unwanted pests in different countries. Hence, in many countries 
of the world, wood pallets are not even permitted into the country unless 
they have been properly fumigated. This has caused a tremendous cost 
impact on those entities employing wood pallets for the purpose of 
shipping goods from place to place. The net result is that there has 
developed a strong tendency toward pallets constructed of alternate 
material. 
In this connection, the art has gravitated to corrugated pallets which are 
made of corrugated paper and other materials which are relatively 
inexpensive, are capable of bearing weight, and are totally recyclable. 
Applicant has patented a certain pallet leg for a corrugated cardboard 
pallet under U.S. Pat. No. 4,487,136 which discloses and claims a 
corrugated pallet having leg elements which are installed onto the pallet 
deck, which yields a corrugated pallet having sufficient strength for 
virtually all applications in connection with the stacking and transport 
of goods placed thereon. Assignee's later U.S. Pat. No. 4,850,284 has 
further disclosed an improvement which relates to the cross-laminating of 
the cardboard pallet decks in order to further enhance the rigidity and 
strength of the subject pallet. 
In both instances, the method of attaching the pallet leg to the pallet is 
by die cutting a plurality of finger members in a tangentially radiating 
manner in order to create a substantially spiral pattern with the fingers. 
The core legs are installed onto the pallet deck by twisting an inner leg 
in the direction of the spiral pattern of the finger elements, and nesting 
the inner leg within an outer leg having the fingers interposed in the 
annulus formed there between. Attachment is achieved by means of the use 
of an adhesive which is applied to the finger elements such that once the 
finger elements are nested within the annulus formed between the inner and 
outer leg elements, the cores forming the leg elements will become 
adhesively secured to the pallet deck via the finger elements. 
It will be appreciated from the above description, that the method of 
attachment relates to the positioning of an adhesive such as a glue, on 
the outer as well as inner surfaces of the finger elements such that when 
the finger elements are interposed or nested within the annulus formed 
between the outer and inner leg elements, the finger elements will become 
adhesively secured on both surfaces to the respective core leg elements. 
It has been observed, however, that when the adhesive is applied in this 
manner, the adhesive merely spreads over the skin or surface of the outer 
surface and inner surface of the finger elements. Hence, the ability to 
secure the core legs to the deck is strictly a function of the securement 
which is achieved by the adhesive being interposed between the surface of 
the finger elements and the respective inner or outer leg element. While 
this has produced a pallet which has a high degree of strength and 
rigidity, and permits a great degree of weight to be stacked onto the 
pallet, and also provides a pallet having legs which are securely attached 
thereto, it has now been determined that the securement of the pallet legs 
to the pallet may be further enhanced by virtue of the present invention. 
Hence, the present invention is intended as a method of further enhancing 
the securement of the pallet legs to the pallet deck in order to further 
strengthen the pallet as a whole, and especially, to enhance the strength 
of the attachment or securement of the legs to the pallet deck. This 
feature has an impact since these pallets are utilized in connection with 
forklift vehicles which are employed for lifting and transporting the 
pallets from place to place. The use of such forklift vehicles is 
widespread and common knowledge, however, it is also known that the use of 
these types of vehicles, will often cause damage to the pallets where the 
tynes of the forklift strike the pallet legs when the operator attempts to 
position the forklift vehicle in a proper position to lift the pallet for 
transportation purposes. Hence, it is believed that the present invention, 
by providing a greater bond between the leg elements and the pallet deck, 
enhances the value of the pallet and further reduces the possibility of 
damage which occurs by the use of forklift vehicles. 
OBJECTS AND ADVANTAGES 
It is therefore the principal object of the present invention to provide an 
improved corrugated pallet which incorporates therein a leg which is more 
securely attached to the pallet deck thereby to further increase the 
strength and shear resistance of the pallet to damage. 
In connection with the foregoing object, it is a further object of the 
present invention to provide an improved corrugated pallet of the type 
wherein the core legs are attached to the pallet deck by means of die 
cutting a plurality of finger members in a spiral configuration such that 
the cores may be attached by twisting an inner core leg into an opening 
created by the die cut pattern of the finger elements and interposing the 
finger elements between the inner leg and an outer leg element, and by 
further die cutting into the finger elements a plurality of perforations 
linearly aligned such that an adhesive applied to the surfaces of the 
finger members incident to the securement procedure, will penetrate the 
inner confines of the finger elements and introduce adhesive into the 
corrugated inner structure of the finger elements such that when the 
adhesive dries, the core leg elements are more securely held onto the 
pallet deck. 
In connection with the foregoing objects, a further object of the present 
invention is to provide a pallet leg and method of attachment of the leg 
to a pallet deck wherein a plurality of linearly aligned perforations are 
provided in each of the finger elements, such perforations being 
positioned within the confines of the finger elements in a manner spaced 
slightly outwardly from the circular score line which bears substantially 
the same diameter as the inner leg element, and terminating at a point 
spaced inwardly from the central circle such that the structural integrity 
of the finger elements is not destroyed. 
Further features of the invention pertain to the particular arrangement of 
the parts and the method of operation, all of which is more fully 
disclosed in the specification set forth hereinafter, and specifically set 
forth in the claims. 
SUMMARY OF THE INVENTION 
In summary, the present invention provides an improved corrugated pallet 
wherein the pallet legs are more securely affixed to the pallet deck, and 
also provides a method for manufacturing such an improved pallet. The 
improvement resides in the recognition of the provision of a series of 
linearly aligned perforations extending along the length of each of the 
finger elements which are in turn, the securement means for securing the 
pallet leg elements to the pallet deck, such that an increase in the 
strength and shear resistance of the corrugated pallet legs is achieved. 
The perforations provide a means for the adhesive to penetrate and 
permeate the interior portions of the corrugated material forming the 
fingers thereby providing an improved adhesive base for adhesively 
securing the leg elements to the pallet deck. The method provides the 
additional step of die cutting into the finger elements, incident to die 
cutting the finger elements per se, a series of linearly aligned 
perforations penetrating the skin or surface of the corrugated pallet deck 
material, thereby to afford the adhesive an entry into the interior 
portion of the finger elements and spreading the adhesive such that the 
finger elements are more securely fastened to the leg elements.

DETAILED DESCRIPTION OF DRAWINGS 
With reference to FIG. 1 of the drawings, there is shown a typical 
corrugated pallet 10 of the type generally represented in U.S. Pat. No. 
4,487,136. This type of construction generally is formed from a pallet 
deck 11 to which a series of four legs 12 are secured. The method of 
securement of the pallet legs 12 to the pallet deck 11 is generally 
disclosed in U.S. Pat. No. 4,487,136. As indicated therein, the pallet 
deck 11 is die cut in each position where a pallet leg 12 is intended to 
be secured, by die cutting an opening consisting of a series of finger 
elements of a generally triangular configuration, having as their base a 
circular score line 14 (See FIG. 3), which defines a hinge point for each 
finger. The finger elements extend to an interior circle 16 as is 
understood, again, from the description set forth in U.S. Pat. No. 
4,487,136. For purposes of the present description, each finger element 
shall be referred to by the numeral 20. 
In connection with the assembly of the pallet 10 as shown in FIG. 1, the 
pallet deck 11 is introduced into a die cutting machine, which will die 
cut the finger elements 20 in the positions required in order to insert 
the legs 12, whether there be four or more legs. Once the finger elements 
20 are die cut, an inner leg member 22 is inserted downwardly through the 
circular score line 14 and twisted in the direction of the arrow as 
depicted in FIG. 5 of the drawings by the numeral 18. It will be 
appreciated that adhesive is first applied to the inner surface 21 of the 
fingers 20 (FIG. 3) prior to the insertion of the inner leg member 
therein, such that once the inner leg member 22 is pressed downwardly 
therethrough, the adhesive (not shown) will spread over the surface skin 
of the finger element 20 and come into touching contact with inner leg 
member 22. 
As indicated in both U.S. Pat. Nos. 4,487,136 and 4,850,284, adhesive 25 
(FIG. 5) is also applied to the outer surface of the finger element 20, 
such that when the outer leg member 26 is positioned on the outer surface 
of each finger element 20, the adhesive will expand and cover the outer 
surfaces of finger elements 20 relative to the interior side wall of the 
outer leg member 26. 
As described and shown, the corrugated pallet 10 will therefore consist of 
a pallet deck 11 which has a plurality, such as four or more, leg members 
secured thereto, by means of a plurality of die-cut finger elements 20 
which are die cut in a substantially tangential manner in order to create 
a substantially spiral pattern. 
As has been indicated in the past, the spiral pattern is important to the 
integrity of the pallet for the reason that when the inner leg member 22 
is inserted and pressed downwardly to nest within the outer leg member 26, 
it is rotated in the manner indicated in FIG. 5, and this rotational 
movement will fix the finger elements 20 in a nesting position in the 
annulus created between the inner and outer leg elements as depicted in 
FIG. 6 of the drawings. As has been indicated in the past, when the finger 
elements 20 are cut in a sunburst pattern as is known in the prior art, 
and not in a spiral pattern as indicated herein, the downward insertion of 
the inner leg member relative to the outer leg member has a tendency to 
cause a tearing of the finger elements thereby weakening the pallet 
structure. Hence, both U.S. Pat Nos. 4,487,136 as well as 4,850,284 have 
described a corrugated pallet which has far superior strength capabilities 
in terms of not only load bearing, but also in terms of resistance to 
shearing from the use of forklift vehicles. 
FIG. 2 is merely intended to illustrate still another version of a 
corrugated pallet which is intended to be within the scope of the present 
invention. The pallet illustrated in FIG. 2 is generally represented by 
the numeral 40, and is generally referred to as a double deck pallet. The 
double deck pallet includes an upper deck 42 and a lower deck 44 which are 
maintained in spaced apart secured position by means of a plurality of leg 
members 46. It is contemplated by the present invention that regardless of 
whether one constructs a pallet in accordance with FIG. 1 consisting of a 
single deck pallet, or a pallet constructed in accordance with FIG. 2 
consisting of a double deck pallet, the method of the present invention, 
and the resulting product, applies. 
As more specifically shown in FIGS. 3, 4, and 7 of the drawings, the 
present invention contemplates a plurality of finger elements 20 which, 
when die cut in the manner indicated, are further die cut in a manner to 
include a series of perforations 28 (See FIG. 3) which extend linearly 
along the length of each of the finger elements 20. The perforations 28 
(FIG. 3) once die cut, penetrate the surface skin of the finger elements 
20, and therefore allow access to the interior confines of the corrugated 
forming the material of the deck 11. As depicted in FIG. 3 of the 
drawings, the perforations may assume the configuration of elongated 
slots, and extend along the linear length of each finger element 20. 
However, it is important that the perforations be spaced both from the 
circular score line 14, as well as spaced inwardly from the interior 
circle 16 (See FIG. 3) in order to maintain the structural integrity of 
the corrugated material. It will be apparent from viewing FIG. 3 of the 
drawings that the finger elements 20 are in the form of a triangular 
configuration with the point of the triangle adjacent to the interior 
circle 16. It is therefore important that the perforations not extend all 
the way to the interior circle 16, but rather, be spaced inwardly 
therefrom. Furthermore, since the finger elements 20 extend from the 
circular score line 14, again, it is important that the perforations begin 
at a point spaced outwardly and away from the score line 14. It is 
preferable that perforations 28 be spaced at least 0.25 inches from the 
circular score line 14, and terminate at a distance not greater than 0.5 
inches from the interior circle 16. These distances represent an 
anticipated safe margin for insuring that the structural integrity of each 
of the finger elements 20 is not destroyed incident to the manufacturing 
process. 
As depicted in FIG. 4 of the drawings, where the corrugated pallet is 
constructed by having an upper double deck wherein there are 
cross-laminated layers of corrugated forming the upper deck 11, each of 
the upper decks will be die cut to create a plurality of finger members 
20. As depicted therein, when the finger elements 20 of the upper deck are 
die cut and the finger elements 20 of the lower deck are die cut, a 
cross-pattern is achieved such that the respective finger elements 20 
overlie one another but in a crisscross pattern. This construction has 
been explained in U.S. Pat. No. 4,850,284. It will be appreciated from a 
view of FIG. 4 of the drawings, that the method of the present invention 
may similarly be employed in that perforations 28 are die cut into all of 
the finger elements 20 such that when the adhesive is applied as generally 
depicted in FIG. 5, the adhesive will be allowed to permeate both finger 
elements 20 from each of the multiple decks forming the corrugated pallet 
10 or 40. 
An alternate embodiment of the present invention is depicted in FIG. 7 of 
the drawings. In this embodiment, the perforations are in the form of a 
series of circular perforations 30, and are shown to be, once again, 
linearly aligned along the length of each finger element 20. Once again, 
it is important that the spacing requirements indicated hereinabove be 
maintained in that the perforations 30 should be spaced approximately not 
less than 0.25 inches from the circular score line 14, and should 
terminate not more than approximately 0.5 inches from the interior circle 
16. Again, it is important to maintain the structural integrity of the 
finger elements 20 and it is therefore deemed desirable not to extend the 
perforations 30 or elongated slots 28, to the very tip ends of the finger 
elements 20 adjacent to the interior circle 16. It is believed that such a 
construction would weaken the tip ends of the finger elements 20 and take 
away from the structural integrity of the pallet assembly as a whole. 
It will be appreciated from a view of FIG. 4 of the drawings, that where a 
corrugated pallet having an upper double deck is constructed, each of the 
finger elements 20 would be perforated with perforations 28 as illustrated 
therein, and hence, when adhesive is applied to each of the fingers, the 
adhesive is permitted to permeate and enter into the interior confines of 
the corrugated material such that upon setting, both the inner leg member 
22 as well as outer leg member 20 will have a greater adhesive base for 
securement to the fingers 20 generally, and hence, the pallet 10 as a 
whole. 
Present research indicates that when a corrugated pallet having a core leg 
assembly in the manner indicated herein is affixed to the pallet deck in 
the manner set forth herein, but further including the perforated finger 
elements, the securement of the legs to the deck is strengthened by a 
factor of anywhere between fifteen (15%) and forty (40%) percent greater 
than the securement of legs heretofore achieved with corrugated pallets 
constructed in accordance with present techniques. 
It is further contemplated that it is possible to perforate each of the 
finger elements in a wide variety of patterns, or indeed, to create 
perforations in double or triple rows extending down the length of each 
finger element. It is contemplated that the criticality in any such 
perforating of the finger elements requires that the structural integrity 
of the finger elements be maintained such that during the manufacturing 
procedure for insertion of the legs into the deck material in order to 
create the pallet, the fingers maintain their structural integrity and not 
be subject to shearing or tearing. It is apparent that perforations do 
tear the surface and skin of the corrugated, and hence, it is believed 
that the greater the number of perforations, the greater the integrity of 
the finger is violated. Hence, it is believed that there is a requirement 
that there be a balance between the number of perforations, and the 
maintenance of structural integrity. A perforated pattern in accordance 
with the description set forth herein has been found to increase the 
strength and securement of the pallet legs to the pallet deck thereby 
creating a corrugated pallet having yet superior strength and shear 
resistant qualities. 
While there has been described what is at present considered to be the 
preferred embodiments of the invention, it will be understood that further 
modifications may be made therein, and is intended to cover in the 
appended claims all such modifications as fall within the true spirit and 
scope of the invention.