Note: Descriptions are shown in the official language in which they were submitted.
2 ~ 2
This invention relates to pallets, including slave
pallets, for use in the shipment and storage of merchandise.
A variety of pallets of various constructions have ~-
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been used and designed over the years. A simple form of ; ~
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pallet that has been used for years is made of wood and
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comprises a platform or upper surface made from a single
wooden sheet that is plywood or from wood slats. The
platform is generally supported by parallel wooden frame
members or beams that are spaced apart to provide openings ~-
for the insertion of the forks of a forklift truck. The
lower surfaces of the frame members or beams can be
connected by a single sheet of material or by slats. one
known difficulty of these wooden pallets is that they tend
ts be heavy which causes handling difficulties and results
in high transportation costs. Wooden pallet are readily
damaged and have proven to be difficult to dispose of. All
metal pallets are also known but these are generally heavy
and expensive to construct.
U.S. Patent No. 3,722,430 issued March 27, 1973 to ;;;
Clifford E. Woodley et al. describes a pallet having an
upper continuous, rigid sheet of plywood, chipboard or
plastic and a lower sheet or set of strips or runners
connected to the upper sheet by cylindrical chipboard
spacers. Metallic eyelets fit centrally through the spacers
which are distributed at regular intervals on the lower
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surface of the upper sheet. The forks of a lift truck can
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be inserted from either end or from either side of the
pallet.
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U.S. Patent No. 3,910,202 issued October 7, 1975 to
Air Sea Packaging Inc. describes a pallet having a platform
of corrugated flberboard or other suitable board material
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supported on moulded plastic legs. The bottoms of the legs
are connected by bottom runners. The legs are in the form
of hollow cups having annular lips at their upper ends for '
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attachment of the legs to the platform. The preferred
runners have channels extending therethrough and each has
an elongate opening in the top surface communicating with a
respective channel. ~i -
The present invention provides a pallet which is both ~ ~;
strong and light compared to other pallets. Both pallets
with legs supporting a platform and slave pallets comprising
load bearing platform members of novel constructlon are ~ - ~
disclosed herein. The pallets of this invention can be `~ ,~"
constructed using known manufacturing techni~ues and readily
available materials.
According to one aspect of the present lnvention a
pallet for use in the shipment and storage of merchandise
includes platform means for supporting material including `
two parallel spaced-apart sheets and an interposed, high
compressive strength core of honeycomb material secured
therebetween. A plurality of leg members support the
platform and are attached to a lower surface thereof. ;~
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Openings are provided between the leg members to receive the '.'. ; ~f'''',".'
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forks of a lift truck inserted therein.
In a preferred embodiment of the pallet, the leg
members are made of tubing adhesively bonded to the lower
surface of the platform. The tubing can be steel cylinders ~ ~;
lined with high compressive strength cardboard cylinders.
According to another aspect of the invention, a pallet
for use in the shipment and storage of merchandise includes
a platform or upper panel for supporting material including
two parallel spaced-apart sheets and an interposed core made
of closely spaced, high compressive strength cardboard rings
securing the sheets together. This pallet also has a number
of leg members supporting the platform means and arranged in
rows on a lower surface of the platform. Openings are
provided between adjacent rows for the passage, in use, of -
lifting forks therebetween and there are means for
connecting together the bottom ends of at least some of the
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legs in at least some of the rows.
According to a further aspect of the invention, a ~;
load bearing platform for use ln the shipment and storage of ;
merchandise comprises a high density plastic panel with
upper and lower surfaces and at least one reinforcing metal
sheet embedded in the plastic panel between its upper and
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lower surfaces and secured therein. ~ ~
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In a preferred form of the aforementioned pallet, the
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plastic panel is made of polyethylene. Leg members depend
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from the platform undersurface and are arranged in rows on
this undersurface.
According to still another embodiment of the invention
a pallet for use in the shipment and storage of merchandise
includes a top panel forming a platform for supporting
material, this panel including two parallel spaced-apart
metal sheets and an interposed core securing the sheets
together. A number of leg members depend from the top
panel and are arranged in rows on a lower surface thereof. -;
A one piece, plastic bottom panel connects together the leg
members at the bottom ends thereof. ~ ~;
A preferred form of core in the aforementioned pallet ~ , -
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is made of lightweight metal honeycomb material. The
preferred leg members include steel cylinders with steel
tops adhesively bonded to the top panel.
Further features and advantages will become apparent
from the following detailed description taken in
con;unction with the accompanying drawings.
In the drawings,
Figure 1 is a perspective view of a pr~ferred form of
pallet constructed in accordance with the present invention
taken from the top and to one side;
.
Figure 2 is a cross-sectional elevation taken along
the line II-II of Figure 1 and showing the construction of
one leg member, the upper panel connected thereto and a
bottom runner; ;~
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Figure 3 is a perspective view similar to Figure 1 but
showing another embodiment of a pallet constructed in
accordance with the invention;
Figure 4 is a bottom view of the pallet of Figure 3;
S Figure 5 is a cross-sectional view taken along the
line V-V of Figure 3 but showing only the edge portion of ~.
the upper panel or platform;
Figure 6 is a plan view of another embodiment of a
pallet constructed in accordance with the invention whereln
a portion of the upper sheet has been broken away to
illustrate the core material below this sheet;
Figure 7 is a plan view of still another embodiment of
the present invention showing only the upper panel of the ;
pallet;
Figure 8 is a cross-sectional view taken along the
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line VIII-VIII of Figure 7 and showing only the upper panel .~
of a pallet; :. : ;`:
Figure 9 is a cross-sectional view similar to Figure 8
but showing a variation of the upper panel;
~20 Figure 10 is an end view detail of one form of runner
usable on the pallet;
Figure 11 is an end vlew detail of another form of ; .
runner usable on the pallet; . -:'
Figure 12 is a cross-sectional detail similar to the `
bottom portion of Figure 2 but showing another way of
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: connecting a leg member to a runner or bottom panel;
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Figure 13 is a cross-sectional detail view showing
another form of leg member and another form of runner
connected to the bottom end of this leg member; ~ ~ ~
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Figure 14 is a plan view of a further embodiment of
the present invention; and
Figure 15 is a sectional elevation taken along the
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line XV-XV of Figure 14. --
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A pallet 10 for use in the shipment and storage of a ,
load of merchandise comprises platform means 12 for
supporting the load, on which the load is normally stackedand a number of leg members 14 depending from the platform
means and distributed in rows on a lower surface thereof.
Openings 16 are provided between adjacent rows of leg
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members 14 to permit the insertion of the forks of a ~ -~
forklift truck in a well known manner. Preferably further
openings 18 are also provided between the leg members so
that the pallet can be lifted by the insertion of the forks
into any of the four sides of the pallet. Preferably means
are provided for connecting together the leg members ln each
row at the bottom ends thereof. In the version of Figures 1
and 2, these connecting means comprise elongate runners or
skids 20.
A preferred construction of a platform or upper panel
12 is shown in detail in Figure 2. Two parallel spaced~
apart metal sheets or diaphragms 22 and 24 extending
substantially the entire width and length of the pallet.
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Interposed between and adhesively bonded to the inner faces
of these sheets is a metal core 26 of lightweight honeycomb
material which per se is of known construction but which, as
far as the applicant is aware, has never before been used in
pallets. The thickness of the core 26 can be selected in
accordance with the required load rating of the pallet. The
core honeycomb can be made of aluminum or aluminum alloy.
Honeycomb aluminum material suitable for present purposes is
available from Pollux Corp. of Jessup, Maryland, U.S.A.
Other possible materials for the honeycomb core include
carbon composites and plastics.
Preferably the upper sheet 22 is made of lightweight
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aluminum or aluminum alloy while the lower sheet 24 can be
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made of steel, if desired, for increased strength. The
upper and lower sheets can be joined at the edges by ~-
channel-shaped strips 28 which can be made of metal or a
suitable plastic material. In one prefered embodiment, the
upper panel is constructed to withstand 110 psi from a load
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supported on its upper surface. However the strength of the ~ ,i
upper panel can vary widely, for example from 50 to 1000 :
psi depending on the particular ~ob requirements. ~ -
A preferred form of leg member 14 as illustrated in
Figure 2. Each leg member is made of tubing and is
adhesively bonded to the lower surface of the platform 12.
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The preferred tubing for each leg member comprises a -~;
galvanized steel cylinder or canister 30. The illustrated
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cylinder has an integral steel top 32 which is the portion
connected to the sheet 24. If desired the top end of the
cylinder can be spot welded to the sheet 24 to secure the ;~ ;~
leg in place while the adhesive bond becomes fully cured.
The preferred steel cylinder has a steel bottom 34 which is ~ i-
firmly attached such as by welding to the side of the
cylinder. In order to provide each leg with improved
compressive strength, a high compressive strength cardboard
cylinder 36 is inserted into the cylinder prior to
attachment of the bottom 34 so that it lines the sidewall
thereof. A preferred form of cardboard material for these
cylinders is resin impregnated cardboard having a
compressive strength of at least 7500 psi. This is a known
material used in the paper industry to provide cores for
1~ paper rolls. In one preferred embodiment, the thickness of
the wall of the cardboard cylinder is 1/2 inch. ;; ~;
In order to improve the appearance of and protect the
pallet, each leg member can be covered with an optional
plastic tube 38, generally extending the entire height of
the leg member. Also if desired, the interior of each leg
member at 40 can be filled wlth a sultable materlal such as
foamed plastic of suitable density to further increase the
strength of the leg. Alternatively, a further steel
cylinder or canister 41 shown in dashed lines can be placed
inside the cardboard cylinder to provide increased leg
strength.
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In one preferred embodimen~ of the pallet 10, the
runners 20 are made of high density polyethylene strips, ~ ;
typically measuring 3/4 inch thick by 6 inches wide. These
strips can be attached by use of a suitable adhesive or
possibly ultrasonic rivets indicated in dashed lines at 42. ~;
The attachment means may also be self tapping screws.
Another optional form of attachment consists of the use of ;
aluminum pads or plates 44 that are embedded in the runners,
as illustrated in dashed lines in Figure 2. These pads are
positioned beneath leg members and adhesively bonded to the
bottoms 34 of the leg members.
Turning now to a further embodiment shown in Figures 3
to 5 of the drawings, this embodiment 50 has a top panel 52
forming a platform for supporting material and a number of
leg members 54 depending from the top panel and distributed
in rows on a lower surface thereof. The leg members 54 can
be constructed in the same manner as the leg members 14 of
the pallet 10. However in this pallet the leg members are ~-
connected together at the bottom ends thereof by a one piece ;;
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plastlc bottom panel 56. The panel 56 can be made of solid ~ ~
plastic such as high denslty polyethylene and can have a ~;; ;
thickness in the order of 1 inch. The leg members are ;
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adhesively secured to the bottom panel. If desired a -~
reinforcing metal sheet can be sandwiched in the plastic
panel 56. ; -~;
One form of bottom panel has openings 58 which are ~
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located between the rows of leg members 54. These openings ;
58, which are preferably square, can receive the wheels of
a lifting and transporting device, known as a ~walkie truck~
which can be maneuvered manually about a shop room floor or
warehouse. Again, with this construction the forks can be
inserted from any of the four sides of the pallet 50.
Although only three leg members are shown in each row
in Figures 1 to 3, further leg members in each row can be
provided of course to increase the racking strength of the
pallet.
- The construction of the top panel 52 is similar to
that of the top panel in the first embodiment except for the ;~ ,
construction of the edging 60 along all four sides. Thus as -~
indicated in Figure 5, the top panel has two parallel
spaced-apart metal sheets 22 and 24 and adhesively securing ~ --
these two sheets together is an interposed core of ~--
lightweight honeycomb material 26. The edging 60 comprises ,~
a strip of high density polyethylene which can be recycled
material. The edges of the two sheets 22 and 24 are
embedded in the edging and can be further connected thereto
by rivets 62 formed by a high frequency or ultrasonic
welding process. The plastic rivets extend into holes
formed along the edge of the metal sheet. An epoxy adhesive
can also be used to attach the edging to the edges of the ` ~
metal sheets. In this case, it is desirable to flame treat ~ ~i
the plastic edging material first in a ~er se known manner
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in order to obtain better adhesion to the plastic.
In a preferred form of a top panel 52 the stripping 60
is about 1 lnch wide and its thickness is in the range of ;
1/4 inch to 1 inch.
It will be appreciated by those skilled in the
construction of pallets, that the aforementioned top panel
52 can be used by itself, that is without the leg members or ;;~
the bottom panel, as a platform or slave pallet. A slave ;~
pallet is simply a platform designed to provide a supporting
surface for stacking packages or articles for transport or
storage and may be used to build a load upon a pallet or
even to upgrade the load rating of a pallet. Slave pallets ; ~ ;
are not designed to be lifted directly by the forks of a
forklift truck and do not provide the necessary openings for
a forklift. Similarly the platform means 12 can be used by ~ ~ ;
itself as a slave pallet, if desired.
Turning now to the third embodiment illustrated in `~
Figure 6 of the drawings, this pallet 70 can be constructed
in the same manner as the flrst embodiment except for the ;
construction of the core between the two parallel metal i~
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sheets. Thus this pallet has platform means 72 for
supporting material including two parallel spaced-apart
sheets 74 and 76. Interposed between these two sheets is a
core of closely spaced, high compressive strength cardboard
rings 78 which secure the sheets together. These rings can
; be made of the same material as the aforementioned
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12
cardboard cylinders 36, that is, resin impregnated cardboard
with a compressive strength of 7500 pounds per square inch
or more. These cardboard rings are adhesively secured to
the adjacent metal sheets. Again, it will be noted that
the cardboard rings are ~er se of known construction since
this material is also used as for centre cores for paper
rolls.
It will be understood that the pallet 70 can be
provided with a number of leg members 80 depending from the
platform 72 and distributed in rows on a lower surface of
- the platform. These legs can be constructed in the same ~;~
manner as the legs of the first version illustrated in ~-~
Figures 1 and 2. Also in this version connecting means are
provided for connecting the bottom ends of the legs. These
15 connecting means can be runners as in Figure 1, or a unitary ~ -~
bottom panel as in Figure 3.
The top of a fourth form of pallet is illustrated in
Figures 7 and 8. In this embodiment the pallet has platform
means 87 for supportlng material and leg members dlstributed
on the lower surface of the platform means. In this version
a unitary lower panel, or runners, can be used to connect
the leg members in the same manner as in the embodiments of - `
Figures 1 to 6. However in this version the platform means
or upper panel 87 comprises a high density plastic panel 88
and two metal sheets 90 embedded completely in the plastic
panel and spaced from one another. One preferred form of
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plastic panel is made of polyethylene and has a thickness
from 1/4 inch to 1/2 inch at the perimeter thereof. The
metal sheet 90 can be secured in the plastic panel by means
of rivets formed ultrasonically, if desired. These plastic;- ~-
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rivets extend through holes 92 formed in the metal sheet. ~
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In addition to or as an alternative to these rivets, an
epoxy adhesive can be used to secure the metal sheets inside
the plastic panel. Before using this adhesive, the plastic
material is flame treated in a well known manner. Although
the use of two or more metal insert sheets is preferred, it
- is possible to use a single sheet for some pallet uses. ;~
In a typical embodiment of the pallet of Figure 7, the
flat metal sheets 90 measure 36 inches in each direction
and are centred in the plastic panel which measures 48 ; ;~;~
inches in each direction. The pallet 85 can be provided
. ......
with leg members extending from the platform and distributed
in rows in the same manner as in Figure 1. It is also
- possible to use the platform of Figures 7 and 8 as a slave ;
pallet having no leg members.
Flgure 9 also illustrates an upper panel or platform
for a pallet. Thls platform 94 is similar to the platform
87 except that it has two corrugated metal sheets 96
embedded in the plastic panel 98. In one preferred
embodiment there is a 1/4 inch layer of plastic on both
sides of each metal sheet. It will be appreciated that the
corrugations act to increase the strength and stiffness of
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the platform as well as to enhance the bond between the
metal and the plastic. The use of two or more of the
cor-rugated metal sheets 96 embedded in the plastic panel one
above another is preferred. In the two sheet version
illustrated the corrugations of the two-sheets are arranged
to extend at 90 degrees to one another, thus providing
improved rigidity in both horizontal directions. ;~
Figures 10 and 11 show alternate forms of runners for
pallets constructed in accordance with the invention. In
Figure 10 the runner 100 is preferably made from high
- density polyethylene but the edges of the plastic strip are
protected and reinforced by channel-shaped, elongate edge -
pieces 102. These can be made from a strong durable metal ~ -
such as steel and they can be mechanically secured to the
lS edge of the plastic or adhesively bonded or both. In the
embodiment of Figure 11, the runner 104 has plastic edge -~
portions 106 which extend along opposite sides of a central - ;
I-beam 108 which can be made of steel or other high strength ~ ;``
material. The beam can be embedded in the plastic when the
runner is formed, for example by moulding.
Figure 12 of the drawings illustrates another way of -~
securing the bottom of a leg member 14 to an elongate runner
20. In this case the bottom 34 of the steel cylinder
forming the leg has a central opening at 36 for receiving a
rivet 38. The rivet 38 passes through a suitable hole in
the runner 20 and has a flat end section 40 which is
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preferably embi~dded in the bottom surface of the runner so
that the rivet projects only a short distance from or not at
all from the bottom of the runner. It will be appreciated
that in addition to the mechanical fastener provided by the
rivet, adhesive bonding can also be provided between the
bottom 84 and the runner. It is also possible to replace
the rivet with a screw thread fastener such as a bolt and
nut.
Figure 13 of the drawings illustrates an alternate
form of construction for the leg members forming the pallet
- and for runners connecting these leg members. In this `;~
embodiment, the leg member again comprises a steel cylinder ; ;
112 which is closed at the top end by a steel cap 114.
Connected to the exterior of the cylinder 112 at the top
thereof is a connecting flange member 116 which extends
about the circumference of the cylinder. The flange member
can form part of the connecting means for joining the leg -
member to the lower surface of the platform 12. The flange
member 116, as well as the top cap 114 assist in load
transfer between the leg member and the platform 12. The
cap member 114 ls adheslvely bonded to the bottom of the
platform 12. Also extending about the exterior of the steel
cylinder is optional plastic tube 118.
Connected to the bottom of the leg member 110 is an
elongate runner 120 which in this case is a metal runner
with longitudinal side flanges 122 and 124. If desired the
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runner can also have longitudinal ribs or ridges 126 which
stiffen the runner in the longitudinal direction. The
ridges 126 are arranged and located so as not to interfere
with the attachment of the leg members 110 to the runner.
5The runners 120 can be adhesively bonded to the bottom ends
of the leg members. In one embodiment, the width of the
runner 120 not including the side flanges is 3 inches while
the width of the steel cylinder 112 is 2.5 inches. The ~-
thickness of the wall of the steel cylinder is 0.1 inch ;'
10while the depth of the cap member and the flange member 116
- is 0.5 inch.
~
Another embodiment of a pallet constructed in :~ -
accordance with the invention is illustrated in Figures 14 ~-
and 15 of the drawings. This platform or pallet 130 has a
15horizontal deck 132 made of two parallel, spaced-apart metal
sheets 134 and 136 and connecting these sheets ls a metal
core of llghtweight honeycomb material which has been ;
described above. In one typical embodiment the thickness of
the decks is 5/8 inch. Extending along two opposite sides
20of the pallet are two elongate beams 138 and 140 made of
plastics material. Although the illustrated beams are solid
plastic, the beams can be made hollow when they are formed
by an extrusion process and this helps to reduce the amount
of plastic required. Also, it is possible to use recycled
25plastic to form these beams and this is advantageous for the
environment. An upper edge of each beam is recessed to
17
accommodate the adjacent edge of the deck as illustrated in
Figure 15. Preferably the upper portion 142 of each beam
extends around the edge of the deck as shown and the edge of
the deck is embedded in the side of the beam. More than two
beams can be employed if required, for example, a central ~;
beam between the two side beams.
Extending along the other two sides of the deck 132
are channel shaped strips 28, essentially the same in their
construction as the strips illustrated at Figure 2. Each
strip 28 extends the entire width of the pallet between the
~~ two beams.
It will be appreciated to those skilled in the art ~ ;
that the pallets described herein can be manufactured so
that they are both strong and light in weight. One typical ~ -~
embodiment of a pallet constructed in accordance with the
invention weighs approximately 35 pounds while a wooden
pallet of the same size made with plywood weighs about 70
pounds. A weight reduction of this magnitude can result in
considerable savings in freight charges alone for
manufacturers and distributors using the present pallets.
Platforms and pallets as herein described may be used widely
in the safe transportation and/or storage of many classes of
goods. In the case of the pallets having plastic components
or beams, recycled plastic can be used and this is helpful
to the environment and to resource conservation.
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It will be appreciated by those skilled in this art
that various modifications and changes can be made to the
pallets described herein without departing from the spirit
and scope of this invention. Accordingly all such ;
modifications and changes as fall within the scope of the
appended claims are intended to be part of this invention.
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