Note: Descriptions are shown in the official language in which they were submitted.
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WOOD-METAL COMPOSITE PALLET AND STRUCTURES
FIELD
[0001] The improvements generally relate to the field of composite
forms, and more
particularly, to a wood-metal composite structure.
BACKGROUND
[0002] Wood composites typically consist of one type of wood adhered to
another type of
wood to provide a structural and/or aesthetic product. Some wood composites do
not
sufficiently resist moisture on their own, and thus require relatively costly
coatings, or
relatively complicated moisture barriers, to make them suitable for a given
application.
Furthermore, the adhesive used to assemble some wood composites can wear off
over time.
SUMMARY
[0003] In accordance with one aspect, there is provided a shipping
pallet, comprising: a
wood-metal composite sheet shaped as a body, the body defining an inner
cavity, the wood-
metal composite sheet including at least one metal layer having metal
protrusions extending
away from both sides of the at least one metal layer, the wood-metal composite
sheet
including wood veneer layers disposed on both sides of the at least one metal
layer, the
metal protrusions extending into the wood veneer layers.
[0004] In accordance with another aspect, there is provided a wood-metal
composite
structure, comprising: a wood-metal composite sheet shaped as a body closed
onto itself,
the body defining an inner cavity, the wood-metal composite sheet including at
least one
metal layer having metal protrusions extending away from both sides of the at
least one
metal layer, the wood-metal composite sheet including wood veneer layers
disposed on both
sides of the at least one metal layer, the metal protrusions extending into
the wood veneer
layers.
[0005] In accordance with another aspect, there is provided a method of
forming a wood-
metal composite structure, comprising: providing a wood-metal composite sheet
including
wood veneer layers disposed on both sides of at least one metal layer, metal
protrusions of
the at least one metal layer extending into the wood veneer layers; supplying
the wood-metal
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composite sheet between a compression roller and a mold having a shape of the
structure to
be formed; and bending the wood-metal composite sheet with the compression
roller to wrap
the wood-metal composite sheet around an outer surface of the mold.
DESCRIPTION OF THE FIGURES
[0006] Reference is now made to the accompanying figures in which:
[0007] Fig. 1A is a perspective view of a shipping pallet, according to
an embodiment of
the present disclosure;
[0008] Fig. 1B is a cross-sectional view of the shipping pallet of Fig
1A;
[0009] Fig. 10 is an enlarged view of a portion of the shipping pallet
of Fig. 1B;
[0010] Fig. 1D is an enlarged view of another portion of the shipping
pallet of Fig. 1B;
[0011] Fig. lE is an enlarged view of another portion of the shipping
pallet of Fig. 1B;
[0012] Fig. 2 is a schematic view of a method of forming a wood-metal
composite
structure;
[0013] Fig. 3A is a cross-sectional view of a wood-metal composite
structure, according to
an embodiment of the present disclosure;
[0014] Fig. 3B is a cross-sectional view of the wood-metal composite
structure of Fig. 3A,
having extra layers.
[0015] Fig. 4 is a cross-sectional view of a wood-metal composite
structure, according to
another embodiment of the present disclosure;
[0016] Fig. 5 is a cross-sectional view of a portion of a wood-metal
composite structure,
according to another embodiment of the present disclosure; and
[0017] Fig. 6 is a cross-sectional view of a portion of a wood-metal
composite structure,
according to another embodiment of the present disclosure.
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DETAILED DESCRIPTION
[0018] Fig. 1A illustrates a composite wood structure 10. In the
depicted embodiment, the
composite wood structure 10 (sometimes simply referred to herein as "structure
10") is in the
form of a shipping pallet 11. The shipping pallet 11 shown in Fig. 1A is a bed
used to support
objects during transport. The shipping pallet 11 can also be used to support
stationary
objects. The structure 10 can take other forms, and is not limited to the
pallet 11 described
herein. Some non-limitative examples of alternate forms for the structure 10
include flooring,
walls, and panels. Other non-limitative examples of forms for the structure 10
include closed
structures, such as a house made from a floor, walls, and a roof. An outer
surface of the
structure 10 can have a finishing or lining to provide an aesthetically-
pleasing appearance.
[0019] In the depicted embodiment, the structure 10 is formed from a
sheet of wood
composite material. More particularly, the structure 10 is formed from a wood-
metal
composite sheet 12. The wood-metal composite sheet 12 includes both wood
material and
metal material arranged in the form of a broad, continuous surface. The
structure 10
disclosed herein is a therefore a wood-metal composite structure 10.
[0020] The wood-metal composite sheet 12 (sometimes simply referred to
herein as
"sheet 12") is folded, bent, curved, or otherwise shaped to provide the form
of the structure
10. For example, and as shown in Fig. 1A, the sheet 12 is shaped as a body 14
which
provides the form of the shipping pallet 11. The body 14 in Fig. 1A has a
substantially tubular
or cylindrical shape. More particularly, the body 14 in Fig. 1A has an obround
shape, in that
the body 14 consists of two semi-circular bodies connected by parallel
surfaces that are
tangential to the endpoints of the semi-circular bodies. Therefore, the sheet
12 forms a
substantially rigid shell body 14 and defines the shape of the shipping pallet
11. The body 14
can have other shapes, such as triangular, circular, and rectangular. In an
alternate
embodiment, the body 14 has a box-like shape.
[0021] The sheet 12 is shaped to form the body 14 such that the body 14 can be
manufactured without using mechanical fasteners and without an adhesive to
attach the
components of the sheet 12. Stated differently, the body 14 has overlapping
portions which
are covered by segments or portions of the sheet 12, as described in greater
detail below.
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The body 14 is therefore, in at least some embodiments, substantially seamless
along its
circumference or peripheral length, so as to form an relatively uninterrupted
surface. This
relatively uninterrupted surface of the body 14 helps to reduce the number of
points of stress
concentrations or weakness. The body 14 in Fig. 1A is closed onto itself.
There is no
opening through the sheet 12 which forms the body 14. The expression "closed
onto itself'
refers to the body 14 being an object without an end. For example, in Fig. 1A,
the body 14 is
an annular object without an end. In an alternate embodiment, the body 14 is
interrupted
such that is has at least two ends.
[0022]
Still referring to Fig. 1A, the body 14 of the shipping pallet 11 is at
least partially
hollow such that it defines an inner cavity 16. The inner cavity 16 reduces
the overall weight
of the shipping pallet 11, and allows for the insertion of the forks from fork-
lifts, for example,
to lift and displace the shipping pallet 11 and the objects thereon. The body
14 of the
shipping pallet 11 in Fig. 1A extends along a longitudinal axis 18. The body
14 extends along
the longitudinal axis 18 between longitudinally opposed extremities 20. An
opening 22 is
defined in one or both of the extremities 20. In Fig. 1A, the openings 22 are
extensions of the
inner cavity 16 which extends through the entirety of the body 14. The
openings 22 allow the
forks of a forklift, for example, to be inserted into the inner cavity 16 to
lift or displace the
shipping pallet 11.
[0023]
Referring to Figs. 1A to 1D, the shipping pallet 11 of the depicted
embodiment
includes additional, optional components. The shaped wood-metal composite
sheet 12
which forms the shipping pallet 11 includes elongated bumper portions 24. Each
bumper
portion 24 protects the body 14 of the shipping pallet 11 from impacts. In the
depicted
embodiment, each bumper portion 24 extends in a direction parallel to the
longitudinal axis
18 along a longitudinal side edge of the body 14. Each bumper portion 24 is
curved. More
particularly, each bumper portion 24 has a semi-circular cross-sectional
shape, as shown in
Figs. 1B and 10. The bumper portions 24 can have other cross-sectional shapes.
In an
alternate embodiment, the cross-sectional shape of one or more of the bumper
portions 24 is
rectangular. In another alternate embodiment, the cross-sectional shape of one
or more of
the bumper portions 24 is "S"-shaped. In the embodiment of Figs. 1B and 10,
the bumper
portions 24 are not hollow. More particularly, one or more of the bumper
portions 24 includes
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a filler member 26 disposed within an inner volume defined by the bumper
portion 24. The
filler member 26 reinforces the bumper portion 24 and provides strength
thereto. In the
depicted embodiment, the filler member 26 includes a wood core cut and shaped
to fill the
semi-circular shape of the bumper portion 24. The filler member 26 can include
other
components, or be made from other materials.
[0024] Still referring to Figs. 1A to 10, the shipping pallet 11 can
have optional internal
reinforcements to further reinforce the surfaces of the shipping pallet 11 to
better resist the
loads generated by the objects stored thereon. In the embodiment of Figs. 1B
and 10, the
inner cavity 16 of the body 14 is defined between opposed inner surfaces 28 of
the body 14.
One or more support members 30 are disposed within the inner cavity 16 and
extend
between the opposed inner surfaces 28. In the depicted embodiment, at least
one of the
support members 30 includes a support post 32. The support post 32 is
cylindrical in shape.
The cylindrical support post 32 in Figs. 1B and 10 is also made from the same
wood-metal
composite material that makes up the sheet 12. It will be appreciated that the
support post
32 can be made from other materials, and have other shapes. In Fig. 1A, the
supports posts
32 are spaced apart from one another in a direction that is parallel to the
longitudinal axis 18.
[0025] The wood-metal composite sheet 12 which makes up the body 14 of the
structure
10, and in some embodiments some of its components, is now discussed in
greater detail
with reference to Figs. 1B and 1E. The sheet 12 is composed of one or more
metal layers 34
attached to one or more wood veneer layers 36. Each metal layer 34 is
textured, enhanced,
or otherwise treated to improve its engagement with the wood veneer layers 36
to which it is
attached. In the depicted embodiment, the metal layer 34 has multiple metal
protrusions 38
which extend outwardly from one or both sides 40 of the metal layer 34. Each
metal
protrusion 38 is an extension from the corresponding side 40 of the metal
layer 34 which is
adapted to mechanically engage with another material (e.g. the wood material
of the wood
veneer layer 36). Each metal protrusion 38 can therefore take any suitable
shape, or form
any suitable non-parallel angle with a plane of the side 40, to achieve such
functionality.
Some non-limitative examples of shapes for one or more of the metal
protrusions 38 include
spikes, hooks, ribs, bumps, and teeth. In the depicted embodiment, each metal
protrusion 38
is a burr which is integral with the corresponding side 40 of the metal layer.
The metal
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protrusion 38 burr is formed by machining the side 40 the metal layer 34 to
cut or plow a
path/groove/channel/furrow into the side 40 and displace the material from the
groove or
channel to a position generally above the plane of the side 40, while
permitting the material
to remain attached to the side 40. Examples of treated metal materials are
described in US
patent 5,376,410 to Macke!vie, the entirety of which is hereby incorporated by
reference.
One or more of the metal layers 34 may include the product commercialised
under the name
GRIP Metal TM by GRIPmetal Limited of Toronto, Ontario, Canada.
[0026] The one or more wood veneer layers 36 are disposed on one or both of
the sides
40 of the metal layer 34. When disposed on both sides 40 of a metal layer 34,
the wood
veneer layers 36 sandwich the metal layer 34. One or more of the wood veneer
layers 36
are composed of a relatively thin slice of wood, and is relatively easy to
produce because it
does not require the deconstruction or reconstruction of pieces of wood.
Indeed, the wood
veneer layer 36 may be made by "peeling" a circular wood log or by slicing
large blocks of
wood. Other techniques are possible. The type of wood used for the wood veneer
layer 36
can vary. For example, where the wood veneer layer 36 will be visible and
serve an
aesthetic function, the wood used to make the wood veneer layer 36 can be a
hardwood or a
wood having an aesthetically pleasing growth ring pattern. Conversely, where
the wood
veneer layer 36 will be hidden and serve a primarily structural function, a
relatively
inexpensive softwood can be used. The wood veneer layers 36 are relatively
thin, for
example thinner than about 3 mm or 0.125 in.
[0027] One or more of the wood veneer layers 36 has wood fibers or grains
which have
an orientation. The orientation of the wood fibers may depend on the manner by
which the
wood veneer layer 36 is made. It is observed that the wood veneer layer 36
provides a
relatively stiff resistance to bending in the direction of the orientation of
its wood fibers, while
being relatively pliable in a direction that is transverse to the orientation
of its wood fibers. It
can thus be appreciated that the orientation of the wood fibers can be
selected to optimise
bending and/or pliability of the sheet 12 along any desired direction. The
wood veneer layer
36 can be provided so that the majority of its wood fibers are substantially
parallel to one
another, and oriented in the same direction. For example, at least 70% of the
wood fibers of
the wood veneer layer 36 can be oriented along one direction.
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[0028]
Referring to Fig. 1E, the metal protrusions 38 of the metal layer 34 extend
into the
neighbouring wood veneer layers 36. The metal protrusions 38 penetrate into
the wood
material of the wood veneer layers 36 to mechanically engage the wood material
and
provide a mechanical interlocking action. The metal protrusions 38 are
therefore firmly
affixed within the adjacent wood veneer layers 36. This helps the wood veneer
layers 36 to
resist shear forces which may act to separate the wood veneer layers 36 from
the metal
layer 34. The penetration of the metal protrusions 38 within the wood material
of the wood
veneer layers 36 acts as a mechanical adhesive, thus reducing or eliminating
the need for a
chemical adhesive to bond the metal layer 34 to the wood veneer layer 36. If
the wood-metal
composite sheet 12 is free of adhesive, it can also be immersed in water or
exposed to
humidity.
[0029] A sheet 12 having a specific configuration of metal and wood veneer
layers 34,36
is shown in Fig. 1E. The wood-metal composite sheet 12 includes three metal
layers 34 and
four wood veneer layers 36. Each metal layer 34 is disposed between two of the
wood layers
36. At least some of the metal protrusions 38 of immediately adjacent metal
layers 34 extend
into the same wood veneer layer 36. For example, in the configuration shown in
Fig. 1E, the
metal layer 34A is immediately adjacent to the metal layer 34B on one side 40A
of the metal
layer 34A, and is immediately adjacent to the metal layer 340 on the other
side 40B of the
metal layer 34A. The metal protrusions 38 extending outwardly from the side
40A of the
metal layer 34A penetrate into the wood material of the wood veneer layer 36A,
and the
metal protrusions 38 extending outwardly from one side 40 of the metal layer
34B penetrate
into the same wood material of the same wood veneer layer 36A. Similarly, the
metal
protrusions 38 extending outwardly from the side 40B of the metal layer 34A
penetrate into
the wood material of the wood veneer layer 36B, and the metal protrusions 38
extending
outwardly from one side 40 of the metal layer 340 penetrate into the same wood
material of
the same wood veneer layer 36B. In the configuration of the sheet 12 shown in
Fig. 1E, the
middle metal layer 34A reinforces the sheet 12 and gives it rigidity. The
sheet 12 in other
embodiments can have more or fewer metal layers 34 and wood veneer layers 36.
The
orientation of the metal protrusions 38 of one or more of the metal layers 34
can be selected
to facilitate the shaping of the sheet 12 into the form of the body 14. For
example, the metal
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protrusions 38 can be oriented in the direction along which the sheet 12 will
be folded or
bent.
[0030]
There is also disclosed a method of forming a wood-metal composite
structure.
Referring to Fig. 2, the method includes providing the wood-metal composite
sheet 12
described above. In the depicted embodiment, the sheet 12 is conveyed along
direction D.
The method also includes supplying the sheet 12 between a compression roller
40 and a
mold 42 having the shape of the structure 10 to be formed from the sheet 12.
In the depicted
embodiment, the shape of the mold 42 is substantially obround so as to form
the
substantially obround shape of the shipping pallet 11 described above. The
method also
includes bending the sheet 12 with the compression roller 40 to wrap the sheet
12 around an
outer surface 44 of the mold 42. The method may also include moving the mold
42 and/or
the compression roller 40 to maintain the application of a suitable pressure
on the sheet 12
being conveyed between the compressor roller 40 and the mold 42. In the
depicted
embodiment, the mold 42 is rotatable in direction R about a rotation axis 46.
[0031] Fig. 3A shows the sheet 12 wrapped around the outer surface 44 of
the mold 42 to
create the body 14. The sheet 12 includes a first sheet assembly 12i
consisting of a metal
layer 34 sandwiched between, and attached to, a first wood veneer layer 36i
and a second
wood veneer layer 36ii. The first sheet assembly 12i is fed between the
compression roller
40 and the mold 42. The first sheet assembly 12i wraps around the outer
surface 44 of the
mold 42. Once the outer surface 44 has been substantially covered by the first
wood veneer
layer 36i, the first wood veneer layer 36i is cut. Alternatively, the first
wood veneer layer 36i
can be supplied in a predetermined length. The metal layer 34 continues to be
wound about
the outer surface of the second wood veneer layer 36ii. The second wood veneer
layer 36ii
continues to be wound about the outer surface of the metal layer 34. The sheet
12 can be
wound in this fashion to form the body 14 having as many layers 34,36 as
desired, and thus
can spiral outwardly in a continuous fashion. Fig. 3B shows an example of a
sheet 12
created in this manner. The body 14 is formed from a single metal layer 34, a
first wood
veneer layers 36i and a second wood veneer layer 36ii.
[0032]
Fig. 4 shows an embodiment of the sheet 112 wrapped around the outer surface
44 of the mold 42 to create the body 114. The sheet 112 includes a first sheet
assembly 112i
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consisting of a first metal layer 34i sandwiched between, and attached to, two
wood veneer
layers 36. The first sheet assembly 112i is fed between the compression roller
40 and the
mold 42. The first sheet assembly 112i wraps around the outer surface 44 of
the mold 42
until a leading extremity 112A of the first sheet assembly 112i approaches the
feed between
the compression roller 40 and the mold 42. The first sheet assembly 112i is
then cut to form
a trailing extremity 112B, and a gap 113 is formed between the leading and
trailing
extremities 112A,112B of the first sheet assembly 112i. The sheet 112 also
includes a
second sheet assembly 112ii wrapped around the first sheet assembly 112i. More
particularly, the second sheet assembly 112ii is wrapped around the outermost
wood veneer
layer 36 of the first sheet assembly 112i. In the depicted embodiment, the
second sheet
assembly 112ii consists of a second metal layer 34ii which engages the
outermost wood
veneer layer 36 of the first sheet assembly 112i, and another wood veneer
layer 36 which
forms the outermost wood veneer layer 36 of the sheet 112 when the second
sheet
assembly 112ii covers the first sheet assembly 112i. In the depicted
embodiment, the
second sheet assembly 112ii is pressed into the gap 113 at least partially by
the
compression roller 42 and/or the mold 42, and covers the gap 113.
[0033] Fig. 5 shows an embodiment of a portion of the sheet 212 forming
the body 214.
The sheet 212 includes a first sheet assembly 212i consisting of a first metal
layer 34i
sandwiched between, and attached to, two wood veneer layers 36. The first
sheet assembly
212i has a first gap 213A between its leading and trailing extremities
212A,212B. The sheet
212 also includes a second sheet assembly 212ii wrapped around the first sheet
assembly
212i. More particularly, the second sheet assembly 212ii is wrapped around the
outermost
wood veneer layer 36 of the first sheet assembly 212i. In the depicted
embodiment, the
second sheet assembly 212ii consists of a second metal layer 34ii which
engages the
outermost wood veneer layer 36 of the first sheet assembly 212i, and another
wood veneer
layer 36. In the depicted embodiment, the second sheet assembly 212ii is
pressed into the
first gap 213A at least partially, and covers the first gap 213A. The second
sheet assembly
212ii has a second gap 213B defined between its leading and trailing
extremities
212A,212B. The sheet 212 also includes a third sheet assembly 212iii wrapped
around the
second sheet assembly 212ii. More particularly, the third sheet assembly
212iii is wrapped
around the outermost wood veneer layer 36 of the second sheet assembly 212ii.
The third
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sheet assembly 212iii consists of a third metal layer 34iii which engages the
outermost wood
veneer layer 36 of the second sheet assembly 212ii, and another wood veneer
layer 36
which forms the outermost wood veneer layer 36 of the sheet 212 when the third
sheet
assembly 212iii covers the second sheet assembly 212ii. The third sheet
assembly 212iii is
5 pressed into the second gap 213B at least partially, and covers the
second gap 213B.
[0034] Fig. 6 shows an embodiment of a portion of the sheet 312 forming
the body 314. In
the depicted embodiment, the sheet 312 includes a single metal layer 34 that
engages each
of the wood veneer layers 36. The sheet 312 therefore includes a single sheet
assembly
312i consisting of a single metal layer 34 and multiple wood veneer layers 36.
Beginning at a
10 first end 34D of the single metal layer 34, the single metal layer 34 is
wrapped around and
engaged with an innermost wood veneer layer 36i. A second wood veneer layer
36ii is
supplied, and an inner surface thereof is applied against the single metal
layer 34. The
single metal layer 34 is also wrapped around an outer surface of the second
wood veneer
layer 36ii. A third wood veneer layer 36iii is supplied, and an inner surface
thereof is applied
against the single metal layer 34. The single metal layer 34 is also wrapped
around an outer
surface of the third wood veneer layer 36iii, and the single metal layer 34
terminates at a
second end 34E thereof. Finally, an outermost wood veneer layer 36iv is
supplied, and an
inner surface thereof is applied against the single metal layer 34. The sheet
312 and the
body 314 formed thereby in Fig. 6 is substantially free of joints. Stated
differently, the body
314 has overlapping portions which are covered by segments or portions of the
sheet 312.
The body 314 is therefore substantially seamless along its circumference or
peripheral
length, so as to form a relatively uninterrupted outer and inner surface. This
relatively
uninterrupted surface of the body 314 helps to reduce the number of points of
stress
concentrations or weakness. The body 314 in Fig. 6 is closed onto itself.
There is no opening
through the sheet 312 which forms the body 314.
[0035] Referring to Figs. 3 to 6, the embodiments of the sheet
12,112,212,312 do not
have a mechanical fastener to join the different sheet assemblies together.
Instead, the
sheet assemblies are wrapped over one another, and the metal layers 34 of each
sheet
assembly mechanically attach one sheet assembly to an adjacent sheet assembly.
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[0036] As can be understood, the examples described above and illustrated are
intended
to be exemplary only. The scope is indicated by the appended claims.
