Note: Descriptions are shown in the official language in which they were submitted.
2Q~9~ ~
` wo 92/12061 PCr/US91/09545
- PAPER CARGO PALLEr
R~lated A~plications
This is a continuation-in-par~ of U.S. Ser. No. 07/~35,195, filed
December 26, 1990, ~ntltled NPALLET DESIGN USING PAPER
MATERIALS", the entirety of which is incorporat~d by notice.
Field of the Invention
This invention is a paitet as might be used to support cargo during
that cargo's transportation or storage. The pallet is constructed of
paper. The pallet design involves a central plafform or deck constructed
OT a noneycomb filler bounded on the top and bottom surfaces by
corrugated sheets. To enhance the torsional and deflective s~rength of
the central platform, th~ corrugated sheets ar~ posHioned so that the
corrugations are not parallel. Additionally, the corrugated sheets may be
folded over the edges of the honeycomb cor~ and ~astened tc the other
side. Runners or legs may be included to suppor~ the central plafform.
Background of the Invention
A pallet is a portable, horizontal, rigid, platform used as a base for
assembling, storing, stacking, handling goods as a unit load.
Conventional pallets are typically constructed of wood and are made by
stapling or nailing a number of boards (known as "deckboards") at ~heir
ends to a number of continuous solid boards (known as Ustringers").
The upper set and lower set (wh~re used) of deckboards ~hereby form
an open area defined by the thickness of the stringers. This opening is
used to accommodate a fork lift or hand truck. In this way the pallet may
be moved from place ~o piace by lifting the pallet and its load off the
f!oor.
, "e vasi majoriiy of aii paiiets used in the U.S. are constructed of
.
.
wo 92/12061 2 ~ 2 P~T/uss1/oss4s
wood, b~ wood palle~ have many disadvantages. Laborand material
c~sts for wooden pallets have increased faster than inflation. Because of
their expense, the pallets ara often reused or returned to their place nF
origin. The cost of retuming empty pallets to ~heir owners is obviously
high. Additionally, The averagc weight of a wooden pallet is about forty
pounds. Sinc~ shipping costs are usually tied to the weight of the goods
shipped, the cost of shipping is increased by the weight of the pallet.
Indeed, pallets are sufficiently heavy that sm~ler warehouse workers are
able manually to move the pallets only with some d~icuity. Wooden
pallats are often damaged during use and, be~ause of the pallet cost,
must be repaired if possible or disposed of. Depending upon the
industry involved, paliets may be used between two and four times
before they are disposed of. Disposal of any solid materials including
broken pallets is an increasingly difficult and ~stly problem.
My invention is a pallet constructad of paper involving a cantral
plafform or deck constructed of a honeycomb filler bounded on the top
and bottom surfaces by corrugated sh~ets. To enhance the torsional
and deflective strength of the cen~al platforrn, the corrugated sheets are
positioned so that the corrugations or flutings are not parallel.
Additionally, the corrugated shects may be folded over the edges of the
honeycomb core and fastened to the other side. Runners or legs may
be included to support the central pla~form. In addition to the inherent
strength and low cost of my pallet, by careful selection of construction
rnaterials, my design may be complet21y recycled as pap~r without
separation into constituent parts.
There are a numb~r of pallet designs which are made mostly of
paper.
For instance, U.S. Pat. No. 3,661,0g9, to Shelor, shows a paper
shipping pall~t having a deck having a core section made of small strips
cut from single, double, or triple wall corrugated paper board sheet stock
-. ~
2 ~
~0 92/12061 3 PCr/US91/09545
glued face to face. Sheets of corrugated are glued to the longitudinal
edges of the composite core. The oore and fadng shests are desirably
of a specific ske of corrugated sheets, i.e., having a size "A~ flute or
better. The legs of the pall9t appear to be wooden blocks.
Shelor does not appear to suggest that the flu~es in the facing
sheets are in any relational configuration other than parallel.
U.S. Pat. No. 3,650,459, to TucX~r, shows a paper pailst design
involving a folded corrugatc she0t as th~ cargo support area. That cargo
deck is provided with a num~er of palle~ f~et (which op~rate as spac~r
blocks within the cargo deckj made of molded plastic rnaterial such as
polystyrene. The use of a hon~ycomb core within the cargo support
area is not ciisclosed.
U.S. Pat. No. 3,952,672, to Gordon et ~I, shows a disposable
pallet rnade of a single folded corrugated sheet. The use of a
honeyoomb core on ~he cargo support area is not disclosed.
U.S. Pat. INos. 4,867,074 and 5,001,991, to Smith, each show a
pallet design in which the cargo deck is made up of a large number of
girders folded from corrugateci shee~ and assembled with a series of
cross girders. The use of a honeycomb core in the cargo support area
is not disclosed.
U.S. Pat. No. 4,790,249, to W~bb, shows a pallet desi0n in which
the cargo d~ck is made up of facing sheets separated by a number of
blocks having a speclfic design. The block design involves a cellulosic
material glued together by a bonding material (such as
ureaformalciehyde) all extruded into the shape of a box beam. The
boxes are pos-~ioned so to protect the deck from the tines on a fork l ft.
Netherlands Patent Application 83 00024 shows an interesting
design for a paper pallet. The cargo support deck appears to be
constructed of a number of loops of paper glued ~ogether at a number of
sites within the deck and also giued to a periphery formin~ the edge of
~ -
: ~
:. , - , , ~::
'~ U ?~ 4
WO92/12061 4 p~/US91/09545 ~i
the deck. Neither the usa of a honeycomb core nor the use of
corrugated sh~t in the cargo deck support area is disclosed.
There are few disclosures showing the use of honeycomb
materials in the core of the cargo support deek.
One such disclosur~ is Published U.K. Patent Application
2,213,462-A to Green ~I. This published application shows a paper
pallet design in which the cargo deck is made up of two face sheets of,
e.g., corrugated cardboard and having a an open structlJre such as a
paper or card honeycomb between them. i~ is said that the deck may be
raised from the floor using feet of similar cons~ruction. The deck core is
made to be p0netrable by th0 tines of a fork lift. There is no suggestion
that the corrugated sheets on alternate sides of the core should be
positioned so that the flutes arP not parallei. Furthermore, the disclosure
is silent on the use of a corrugated sheet folded over the edge of the
central core and fastened to the opposite side.
U.S. Pat. No. 4,319,530, to Moog, discioses a pallet, said to be
disposable, having a cargo supporting deck area made up of a central
core of a honeycomb made of laminated corrugate. The core is fa~ed
- with one or more corrugated sheets glued to the core. The facing on the
cargo support surface of the central core may be made up of multiple
layers of corrugated sheets. Although these multiple facing layers are
said to be positionable so to permit Ucross laminating where the flutes of
the d fferent sheets are oriented at right angles~, there is no suggestion
that use of corrugated sheets on alternate sides of the core positioned
so that the flutes are not parallel is useful. Further, ~he disclosure is
silent on the use of a corrugated sheet folded over the edge of the
central core and fastened to the opposite side nor, obviously, is any
benefit accorded such a folded sheet.
None of these disclosures show a pallet construoted of paper
involving a central plafform or deck constructed of a honeycomb filler
; .:
,~- -..... , - .. . ; ...
2~9~ ~
'~.WO9~/12061 5 PCl/lJS91/09545
bound~d on the top and bottom surfaces by corrugated shee~s nor do
these disclosures show th~ features of increased torsionai and daflective
strength of the central platform via the use of car~fully positioned
corrugated sheets such that the corrugations or flutings in those face
sheets are not parallel.
BRIEF DE.~ÇRIPTIQN OF THE~ DRAWlN(~
Figure 1 is an exploded drawing of the ~omponents of the basic
cor~iguration of tha inventiun.
Figure 2 is an sxploded drawing of ~he components of a variation
of the invention.
Figure 3 is a drawing showing a variation of the invention using
runrlars instead of feet to support the cargo deck.
Figure 4 is an exploded drawing of another variation of the
invention.
Figure 5 is a perspective drawing of a four-way entry pallet made
according to the invention.
SUMMARY OF THE INVENTION
In general, this invention is a pallet as might be used ~o support
cargo during that cargo's transportation or storage. The pallet is
constructed of paper. The pallet design involves a central platForm
constructed of a honeycomb fill~r bound~d on the top and bottom
surfaces by corrugated sheets. To enhance the torsional and deflective
strength of the central plafform, the corrugated sheets are positioned so
that the corrugations are not parallal. Additionally, the corrugated sheets
may be foldecl over the edges of the honeycomb core and fastened to
their opposite side. Runners or legs, particularly those utilizing
honeycomb or corrugate cores and corrugate skins and adapted so that
the skins overlap up on to the edges of the central plafform, may be
.
20~91:~
wo 92/l2b6l 6 PCr/US91/09545 T
included to support that central plafform.
Although thè invention may be made of a variety of materials, I
prefer to constrùct the pallet from materials which may be readily
r0cyc~ed using commercially available technology. For instance, the
various sheet material is desirably from kraft pap~r or other similar paper
stock~ Of course, depandirlg upon the seM~e into which the pallet is
placad, other materials may be selected, e.g., MYLAR, polyethylene,
polypropylene (clear or fibrous paper product), or the like is ac~ptable.
Some thermosetting polymeric materials are not currenUy widely
recyclable and may not be the best of choices for the pallet from that
viewpoint. However even with nonrecyclable materials the improvements
of the pallet design will be apparent. Choice of materials and methods to
join together ~he various components of the pallet may also be made on
the basis of recyclability. For instance, most water-based glues, e.g.,
hida glu~, mucilage, ~tc. are glues compatibla with the kraft paper
recycling processes. Heat ealing th6rmoplastic materials such as
polypropylene is an expedient using no adhesive.
Figure 1 is an exploded diagrarn showing ~he components of the
basic c~nfiguration of the invention. In this c~nfiguration, the central core
(100) comprises an expanded honeycomb material. Joined So this core
on the upper and lower faces of the core are two facing sheets (102,
104). If the rnethod for joining the ~wo facing sheets to the core is
properly carried out, the cells within the core are isolated from each
other. The core strength is enhanced by the formation of these closed
cells and irnparts an amount of springiness and shock absorbing
eapabilities to the core.
Attached to the facing sheets (102, 104) are two corrugated
sheets (106, 108). The fllnes on the respective corrugated sheets are
depicted such that the flutes on sheet (106) are not parallel to th~ flutes
on sheet (108). The angle between the respect~ve flutes may between
. ~ . " ,. ~ .
. ,.. , :
,
2 ~ 9 ~
:` ~ WO 92/12061 7 Pcr/us9l/095q5
.
about 30 and 9O although for a ve~ practical pallet from th~ vantage
of. strength1 v~rsatility, and ease of construction, an included angle
b~twaen the flutes of about 90' is dssirable.
Attach~d to the outcr ~dges of th0 ~ut~d, corrugatsd shcsts (10~,
108) are sha~ts (110, 112).
Cl~arly, th0 combination of facing she~t (104), corrugatsd sheet
(108), and sh~t (112) and th~ combination of facing shset (102),
corrugated sheet (106), and shest (110) are commonly available articles
of commerce which may be employed in the invention.
This invention is not limited to the basic variation shown in Figure
1. Addltional sheets of corrugated material may be added to the upper
and lower faces of the cornbination shown in that Figure ~ additional
strength is needed for some particular purpose. Addltion of a sheet on
the upper lor load-bearing fac0) is preferable to enhance the impact
resistanc~ of the pall~t deck.
As will be discuss0d below, addition of runners. Iegs, etc. to rnake
a practical pallet is desirable but the basic components of the invention
are shown in Figure 1.
The pallet may be coated w~h a material which will harden or
waterproof or dustproof the pallet. These materials may be chosen to
meet whatever criteria are appropriate for the pallet use. For instance, if
used in a humid atmosphere or used outside or are moved between
refrigerated and non-refrigerated areas, waterproofing is desirable.
Known water-based and oil-based materials may be applied as needed.
Addltionally, th~ cargo fac~ of the deck may be covered with or
coated with a suitable mat~rial to prevent slippaga of the cargo.
Figure 2 shows an explod~d drawing of a variation of the
invention. Beginning with the basic combination shown in Figure 1, the
variation in Figure 2 involves a honeyc~mb core (200). Ths lower sheet
(202) is a combination corruga~ed sheetstock (similar to a cornbination of
. ~
, ~
. . .
-
WO 92/12061 ~3 pcrlus91lo95~5 ,~-
sheet 102, corrugated sheet 106, and sheet 110 shown in Figure 1). It is
a~proximately the size of the lower face of honeycomb core (200~. The
upper sheet (204) is configured so that it may be folded over the edge of
the honeycomb core (200) and overlapped onto and fastened to the
lower sheet (~32). As with the Figure 1 variation, the flutes in the upper
sheet (204) are not parallel to the corrugated fl~as in the lowar sheet
(202). This feature, in add~ion to th~ provision of ~he tabs (206)
adhesively fastened to lower sheet t202), provides additional strength to
~he pall~t cargo support platform.
Add-~ionally, the pallet may have feet of the construction shown in
Figure 2. The legs may have a center block (208) made preferably of a
honeycomb material similar to the core (200). They may also be made
of an assembly of corrugated sheet if so desired. Ths center block is
covered with a skin of a corrugated material (~10) having a number of
tabs which may be folded as shown (212) and glued together to form the
foot (214). It may be seen from Figure 2 that foot (214) has tabs which
are then adhesively flxed to the outside corners of the cargo support
decking made of core (200), upper sheet (204), and lower sheet (202).
Of course, ~ a foot is desired in the middle of a side of the decking two
extended tabs ore not necessary; one will do. Ths tabs on the feet on
the outside periphery of the cargo support decking are desirable since
they prevent the feet from being separated from ~he decking by a
misplaced tine on a forklift.
Figure 3 shows a pallet made according to ~he invention. It is
made of a top deck covered by a top sheet (302) of a corrugate sheet.
It has an expanded honeycomb core (304) and an adhering lower skin
(306) also of a corrugate sheet. The runners (3~8) are made up of a
corrugate tray (310) enclosing a portion of expanded honeycomb core
(312). The runners (308) are adhesively secured to the underside skin
(306). The runners utilize tabs (314) to allow sturdy attachment of the
~ .
- . , . ., , ~ ~
, ~: wo 92/t206l 9 2 ~ ~ 9 ~ ~/usg1/09545
runners to the top deck assembly.
The Figure 3 embodiment is a design known as a two-way entry
pallet. The wide slots between the runners on the underside of th0 cargo
deck permit entry of forklffl or hand truck tines from e~her of opposite
ends.
When the pallet of this invention is used in conjunction with roller
conveyer systems, a hard paperboard (316) may be glued to the bottom
of the runner trays (310). The paperboard is typically one-fourth to ona-
haK inch in thickness and made form thin sheets of paper glued and
compressed together to give a hard surface to the bottom of the runners.
rne hard surface prevents the bottom of the corrugatè trays from
depressing around the conveyer roller and ~hereby preventing the load-
bearing pailet form rolling easily down the conveyer. The hard
paperboard provides adequate hardness for reducing the compressibility
of the runner bottom and therefore reduces the drag on the pallet.
Figure 4 shows a variation of the pallet shown in Figure 3 but in
which the lower corrugate sheet is integrated with the runner tray to
enhance the overall strength of ~he runners. In this variation, the deck
includes an expanded honeycomb core (402) and an upper face (404) of
corrugate. The runners and ~he lower deck facing are made of a set-of
runner cores (406) of expanded honeycomb or multilaminated corrugate
and a lower folded corrugate sheet (408). The lower corrugated folded
sheet (408) adheres to and encloses the runner core blocks (406). It
also has tabs (410) which may be folded over and allow it to adhere to
the cargo (or upper) surface of the upper corrugate face (404). Similarly,
the upper corrugate face (40~) adheres to the honeycomb core (402) by
use of adhesives, glue, or solvents and also has tabs (412 which may be
folded under the runner core blocks (406) and ~abs (414) which may be
folded under the honeycomb core (402). The runners obviously cannot
be separated from the deck without the virtually complete destru~tinn of
: , ,......... -
, :. . ,. :
wo s2~l~0Ql9 91 ~ ~ PCI-/US91/0954; '~i
the pallet.
Figure 5 shows a four-way pallet made according to the invention.
As with the variations discussed above, the pallet incorporates a cargo
deck (502) made up of an upper and lower skin surrounding a
honeycomb core. The deck is supported by a lumber of legs (~4) each
having gussets reaching up onto the edge of the cargo deck. Placement
of the legs in the manner shown allows entry of forklift or hand truck
tines beneath the cargo deck frorn any side, e.g., into the slots shown
via directions "x" and "y".
EXAMPLE
This example demonstrates the strength of the pallet deck made
according to the invention by comparison to decks made in other ways.
In this example a series of pallet decks were constructed using expanded
honeycornb as a core. Th~ core was glued to the core using an
industrial mucilage, approved by the FDA for use with foodstuffs. Each
core was about four foot by four foot. Thc core was a 1-1/2 " thick
expanded honeycomb of 33 Ib. paper arranged into 1/2" cells.
Th~ first deck (Deck "AU) was made using a good grade of paper,
i.e., 42 Ib. kraft paper, as the upper and lower skins on the core. The
paper did not cover the edge of the core.
A second set of two identical decks (Decks ~su and "CU~ was
made using corrugate skins (200 Ib. test corrugate) in which the flutes in
the skins were parallel to 0ach other. The skins were glued to the
honeycomb core. The edges of the core were not covered.
A fourth deck (Deck "D") was made in the same fashion as Deck
"C" using corrugate skins in which th0 flutes were at right angles to each
other. The edges of the core were not covered. This deck is in accord
with the invention.
A fifth deck (Deck UE") was made also in accord with thi.s invention
,; .~ . .. ...
,
2~9~
WO 92/12061 1 1 Pcr/US91/09545
in the same fashion as Decl~ "D" except that one skin was wrapped
around the edge of the core and glued to the other skin.
Each of th~ decks was mount~d on a testing table. The
approximately two feet of the decks overhung the edge of the table. The
end of th~ deck on the table was secure~ clamped to the table. The
edge overhanging the floor was loaded with increasing weights until the
deck bent at the edge of table and sustained a 15- bend. The two
decks with parallel ~utes in the corrugate skins ~decks "B' and UC") were
tested w~h so that flutes were either p~rpandicular to the table edge or
parallel to the edge.
The results of the tests were as shown in the table.
TABLE
_ _ _ --_ = _ -
Deck Skin Parallel Edge Failure
Type Flutes? Cover? Weight
_.--. _= , -._. =_ .
A paper no 26
B corrugate yes no 90
_
C _corrugate yes no _ 72
D corrugate no no 81
E corrugate no yes 88
~ flutes tested p arallel to table ~dge
** flutes tested perpendicular to table edge
A comparison of the failure weight of Decks "B" and "C" shows
that these identical decks have a signfflcant variation in the failure level as
a function of the direction. The two inventive decks UD" and "E" are each
stronger than the weaker direction of the Deck "B"/"C" and inventive
Deck "E", with its covered edge is substantially the same strength as the
strongest of the decks with the non-covered edge.
., ~ :
.
209~
WO92/12061 1 2 PCJ/US91/0954sf~.
The invention has been described by description and by example.
The examples are just examples and are not to be used to lim~ ~he
scope of the invention in any way. Additionally, one having ordinary skill
in this art will recognize variations and equivalents within the inv0ntion as
describ0d which will not necessarily be wi~hin the scope of the appended
claims.
