FIELD OF THE INVENTION
[0001] The invention relates to pallets for supporting items during shipment and storage.
In particular, the invention relates to a pallet formed predominately from fibrous
material.
BACKGROUND OF THE INVENTION
[0002] Pallets traditionally have been manufactured of wood. The drawbacks associated with
wooden pallets are well known, as noted for example in U.S. Patent No. 5,184,558,
incorporated herein by reference. Briefly, such drawbacks include heaviness, which
makes the pallets cumbersome to handle and costly to ship, relatively great expense
because of the costliness of wood, and difficulty and expense of disposing of the
pallets when their useful life has been expended.
[0003] Because of such problems, various types of non-wooden pallets have been proposed.
Some of these pallets are based on corrugated paperboard materials; others are based
on honeycomb sandwich types of sheet materials. Still others are one-piece structures
molded from fibrous material.
[0004] Pallets based on corrugated paperboard materials suffer from relatively poor rigidity
because corrugated paperboard material by its nature is weak in bending parallel to
the running direction of the flutes. Attempts have been made to improve rigidity in
all directions by forming laminations of multiple layers of corrugated paperboard
with the flutes in successive layers being oriented orthogonally. There is thus a
need for a substantial number of separate pieces of corrugated sheet material, each
die cut to appropriate size and shape, the pieces then being glued together. Thus,
production and assembly of a pallet from such materials is relatively complex and
expensive.
[0005] Pallets formed from honeycomb sandwich materials likewise tend to consist of a substantial
number of separate pieces, and hence are relatively complex and expensive to produce
and assemble. Additionally, the bond between the honeycomb cells and the face sheets
represents a weak link in honeycomb sandwich structures; if this bond should break,
the structure loses a great deal of its bending stiffness. In honeycomb sandwich panels
based on paper, furthermore, exposure of the panels to water or other liquids can
substantially weaken the panels.
[0006] With regard to one-piece molded fibrous pallets, a significant drawback is the need
for a differently configured mold for each different pallet size or configuration
to be produced.
SUMMARY OF THE INVENTION
[0007] The invention addresses the above needs and achieves other advantages, by providing
a pallet formed of molded fibrous panel material of a special type having substantial
strength and relatively light weight. The pallet can be constructed from a small number
of separate pieces of the panel material, or even from a single piece of the panel
material.
[0008] More particularly, in accordance with the invention, a pallet is constructed of a
molded fibrous panel material comprising a sheet portion defining opposite planar
surfaces, and a grid of intersecting ribs projecting from one of the planar surfaces
of the sheet portion, the sheet portion and ribs being integrally molded in one piece
from fibrous material. The fibrous material can be, for example, recycled paper fibers.
If water-resistance is required, the molded fibrous panel material can be impregnated
with a suitable resin. The panel has substantial rigidity and integrity by virtue
of its one-piece construction and the grid of intersecting ribs.
[0009] A pallet in accordance with the invention comprises a horizontal portion of the molded
fibrous panel material forming an upper support surface of the pallet, and at least
two spaced runners joined to and extending downward from the horizontal portion for
engaging the ground to space the horizontal portion above the ground. Each runner
comprises at least two vertical portions of the molded fibrous panel material arranged
in parallel relation and bonded to one another.
[0010] In one embodiment, a single panel member is folded along a series of parallel fold
lines extending across a width of the member, so as to form the runners and the horizontal
portion from the single member. Because of the substantial rigidity of the panel,
the grooves are formed in the panel to create the fold lines. The grooves represent
regions in which fibrous material that would otherwise be there is missing or removed.
The grooves preferably are generally V-shaped with a 90-degree included angle between
opposite side walls of the grooves so that the panel can be folded 90 degrees about
the fold line. The grooves either can be molded into the panel when it is molded,
or alternatively can be formed by mechanically removing material (e.g., by routing)
from the panel after it is formed.
[0011] In another embodiment, a top panel is affixed atop the horizontal portion of the
pallet, such as by gluing. The top panel gives added strength to the pallet and also
presents a smooth top surface. The top panel in one embodiment comprises a laminated
multi-layer sheet, for example formed from paperboard sheets. Alternatively, the top
panel can be another piece of the molded fibrous panel material, with the ribs facing
downward toward the horizontal portion of the pallet. The ribs of the top panel can
be bonded to the ribs of the horizontal portion, optionally with an intervening piece
of sheet material (e.g., paperboard or the like) disposed therebetween.
[0012] The molded fibrous panel material forming the horizontal and vertical portions of
the pallet can comprise a single layer of the molded fibrous panel material, such
that one side of the panel is planar and the other side has exposed ribs. Alternatively,
the panel material can comprise a double layer wherein the two layers are joined rib-to-rib,
for added rigidity.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)
[0013] Having thus described the invention in general terms, reference will now be made
to the accompanying drawings, which are not necessarily drawn to scale, and wherein:
FIG. 1 is a perspective view of a piece of molded fibrous panel material used for
constructing pallets in accordance with the invention;
FIG. 2 is a cross-sectional view taken along line 2-2 in FIG. 1;
FIG. 3 is a pallet in accordance with a first embodiment of the invention;
FIG. 4A shows a portion of a molded fibrous panel, illustrating a series of parallel
fold lines defined as V-shaped grooves in the panel;
FIG. 4B shows the panel after being folded 90 degrees along one of the fold lines;
FIG. 5 shows a portion of the panel of FIG. 3, depicting a runner in greater detail;
FIG. 6 illustrates an alternative embodiment of the invention;
FIG. 7 shows another embodiment of the invention;
FIG. 8 depicts a further embodiment of the invention;
FIG. 9 shows a still further embodiment of the invention; and
FIG. 10 shows yet another embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0014] The present inventions now will be described more fully hereinafter with reference
to the accompanying drawings, in which some, but not all embodiments of the invention
are shown. Indeed, these inventions may be embodied in many different forms and should
not be construed as limited to the embodiments set forth herein; rather, these embodiments
are provided so that this disclosure will satisfy applicable legal requirements. Like
numbers refer to like elements throughout.
[0015] FIGS. 1 and 2 show a molded fibrous panel
20 that is used for constructing pallets in accordance with the invention. The panel
20 can be formed by a process generally similar to that disclosed in U.S. Patent No.
4,702,870 to Setterholm et al., incorporated herein by reference, or by a process
such as described in co-pending U.S. Patent Application Serial No. 10/729,686, filed
on December 5, 2003, entitled "Apparatus and Process for Forming Three-Dimensional
Fibrous Panels" incorporated herein by reference. The process produces a three-dimensional
panel that has a sheet portion
22 defining opposite planar surfaces
24 and
26, and a grid of intersecting ribs
28 projecting from one surface
24 of the sheet portion. To make the panel, an aqueous fiber stock is deposited into
a mold comprising a porous support plate or screen on which are affixed a plurality
of resilient elastomeric mold pieces or projections of truncated conical or pyramidal
shape. The mold pieces are spaced apart on the porous support plate so that intersecting
channels are defined between the mold pieces. The aqueous stock fills the mold to
a depth greater than the height of the mold pieces, so the stock covers the upper
surfaces of the mold pieces. A flat mold plate is urged against the stock and presses
the stock down into the mold; the stock is dewatered through openings in the porous
support plate. The pressure dewaters and densifies the panel, and the wet panel is
then dried fully to complete the process.
[0016] The panel
20 advantageously can have a thickness ranging from about ¼-inch to about ¾-inch or
more. The panel can be formed from recycled paper fibers. The panel can be impregnated
with a resin to render it water-resistant, if desired. An advantage of the panel over
the prior art is its relatively large strength-to-weight ratio, which makes possible
the construction of pallets of relatively light weight but substantial strength.
[0017] FIG. 3 depicts a pallet
30 in accordance with a first embodiment of the invention. The pallet
30 is constructed from a single molded fibrous panel
20 and a top panel
50. The molded fibrous panel
20 is rectangular in shape. The panel
20 is folded along a series of parallel fold lines to form three runners
32, 34, 36 spaced apart and parallel to one another, as further described below. The top panel
50 is then bonded to the folded panel 20 by gluing or the like.
[0018] The formation of the runner
32 is depicted in FIGS. 4A, 4B, and 5; the other runners are formed in a similar fashion.
The panel
20 is provided with a series of spaced, parallel fold lines
A, B, C, D, E, F, G, H, I, J (FIG. 3); the fold lines
A, B, and
C are used for forming the first runner
32. The fold line
A is spaced from one edge of the panel
20 by a distance corresponding to a desired vertical extent of the runner
32; panel section
20a is defined between the panel edge and the fold line
A. The fold line
B is spaced from the fold line
A by a minimum distance roughly equal to 1.5 to 2 times the thickness of the panel;
panel section
20b is defined between fold lines
A and
B. The fold line
C is spaced from the fold line
B by a distance approximately equal to the vertical height of the runner minus the
thickness of the panel
20; panel section
20c is defined between the fold lines
B and
C, and a panel section
20d is connected to the panel section
20c at the fold line
C.
[0019] Because the panel
20 has substantial bending stiffness as a result of the ribs
28, it is not possible to fold the panel without substantial breakage of fibers and buckling
of the panel along the fold, and accordingly it is necessary to provide a groove or
channel along each of the desired lines about which the panel is to be folded, as
shown in FIG. 4A. In the region of each groove, the ribs are substantially removed
or interrupted so that the remaining material, at least at the bottom of the groove,
consists substantially entirely of the sheet portion
22 of the panel. A preferred configuration of the grooves is depicted in FIG. 4A. Each
groove preferably is V-shaped; the opposite side walls of the groove preferably define
an angle of substantially 90 degrees therebetween. Accordingly, when the panel is
folded 90 degrees about the fold line, the opposite side walls of the groove come
into substantially abutting relation and can be glued together to secure the panel
in the folded position.
[0020] The V-shaped grooves can be formed in various ways. In one embodiment, the grooves
are formed during the molding process, by suitably configuring the mold. Alternatively,
the panel can be molded without grooves, and then the panel can be routed, machined,
or otherwise mechanically operated upon to remove material to form the grooves.
[0021] To form the runner
32, the panel sections
20a and
20b are folded as a unit 90 degrees clockwise about the fold line
B as shown in FIG. 4B, then the panel section
20a is folded relative to panel section
20b 90 degrees clockwise about the fold line
A. At this point, the panel sections
20a and
20c are parallel to each other and are rib-to-rib. These panel sections are glued together
to form the runner
32. The runner is then folded 90 degrees counterclockwise about the fold line
C, with the resulting structure being shown in FIG. 5. Panel section
20d forms a horizontal portion of the pallet on which a load will be supported. The other
runners
34 and
36 and further horizontal portions are similarly formed by folding the panel about the
respective fold lines
D-J. Finally, the top panel
50 is attached atop the panel
20 by gluing or the like to complete the pallet construction. Although a particular
order of folding the panel
20 about the fold lines has been described, it will be recognized that the order may
be different while arriving at the same end result.
[0022] FIG. 6 illustrates a portion of a pallet
30' in accordance with a second embodiment of the invention. This pallet is essentially
the same as the pallet
30 described above, except that the panel
20 is reinforced in the region of the fold lines
A and
B by a reinforcing web
52. The reinforcing web
52 is employed to prevent or minimize fiber breakage in the region of the fold lines
that may otherwise result upon folding of the panel. The reinforcing web may be an
adhesive tape such as a pressure-sensitive adhesive tape comprising a substrate of
paper or cloth having a layer of pressure-sensitive adhesive thereon. The reinforcing
web preferably is affixed to the panel prior to folding.
[0023] A third embodiment of the invention is depicted in FIG. 7. The pallet 130 shown in
FIG. 7 is generally similar to the pallet
30 previously described, except as noted herein. The pallet
130 has a panel
20 folded along fold lines
A, B, C, etc., so as to form runners
32, etc., as previously described, and a top panel
50 affixed atop the panel
20. However, in the present embodiment, the runners are reinforced with additional stiffening
members. Thus, the runner
32 is shown having a stiffening member
60 disposed between the panel portion
20a and the panel portion
20c that make up the runner. The stiffening member is bonded to the panel portions
20a and
20c with adhesive or the like. To provide the necessary space between the panel portions
to accommodate the thickness of the stiffening member
60, the fold lines
A and
B are spaced slightly farther apart than in the previously described pallet
30, so that when the panel portions
20a and
20c are parallel to each other there is a space between them substantially equal to the
thickness of the stiffening member
60. The stiffening member
60 can comprise various materials, including but not limited to metal, wood, hard plastic,
hard rubber, fiber-reinforced plastic, multi-layer paperboard laminations, and the
like.
[0024] FIG. 8 shows a fourth embodiment of the invention. The pallet
230 of FIG. 8 is generally similar to the pallet
30 described above, except that the top panel
250 comprises a fibrous molded panel of the type shown in FIG. 1. Thus, the top panel
250 has a sheet portion
252 and ribs
258 projecting therefrom. The top panel
250 is bonded to the panel
20 that forms the runners of the pallet. Preferably, the panel
20 has its ribs
28 projecting upwardly and the top panel
250 has its ribs
258 projecting downwardly, and the two panels are bonded rib-to-rib. Optionally, there
can be an intervening sheet
260 of paper or other material disposed between and bonded to the two panels.
[0025] A fifth embodiment of the invention is illustrated in FIG. 9. The pallet
330 of FIG. 9 is constructed in a fashion similar to that used for constructing the pallet
30, except that the starting panel
320 used for forming the runners is a double-layer panel having two panels of the type
illustrated in FIG. 1, bonded rib-to-rib (with or without an intervening sheet therebetween).
Thus, both opposite surfaces of the panel
320 are smooth and planar. The panel is provided with grooves along the desired fold
lines by routing or the like, as previously described, and is folded to form the runners
332, etc., and the horizontal portions
320d, etc. However, in the pallet
330, since the horizontal portions of the panel
320 already comprise a double-layer of panel material, there is no need for an additional
top panel. Thus, the entire pallet is formed from one double-layer panel. As with
the embodiment of FIG. 7, the runners can be further strengthened, if desired, by
stiffening members.
[0026] Finally, a sixth embodiment of the invention is shown in FIG. 10. The pallet
430 of FIG. 10 is formed differently from the previously described pallets, with respect
to the formation of the runners. In this embodiment, each runner, such as the runner
432 shown in the drawing, is formed by bonding together two or more separate and discrete
pieces of panel material, and is then bonded to a top panel of the pallet. Thus, as
shown, the runner
432 comprises two double-layer pieces of panel material
440 and
442 bonded together. The piece
440 comprises two panels
440a and
440b bonded together rib-to-rib (with or without an intervening sheet therebetween); likewise,
the piece
442 comprises two panels
442a and
442b bonded together rib-to-rib (with or without an intervening sheet therebetween). The
pallet
430 includes a top panel
450 comprising a double-layer piece of panel material having two panels bonded together
rib-to-rib (with or without an intervening sheet therebetween). Alternatively, the
top panel could be a single layer of the panel material, or could be another type
of construction such as a multi-layer paperboard lamination. The runners could be
formed of fewer than four layers of the panel material; for example, the runners could
comprise two layers of the panel material. The runners could include stiffening members
as previously described.
[0027] Many modifications and other embodiments of the inventions set forth herein will
come to mind to one skilled in the art to which these inventions pertain having the
benefit of the teachings presented in the foregoing descriptions and the associated
drawings. Therefore, it is to be understood that the inventions are not to be limited
to the specific embodiments disclosed and that modifications and other embodiments
are intended to be included within the scope of the appended claims. Although specific
terms are employed herein, they are used in a generic and descriptive sense only and
not for purposes of limitation.
1. A pallet formed predominately of molded fibrous material, comprising:
a molded fibrous panel material comprising a sheet portion defining opposite planar
surfaces, and a grid of intersecting ribs projecting from one of the planar surfaces
of the sheet portion, the sheet portion and ribs being integrally molded in one piece
from fibrous material;
a horizontal portion of said molded fibrous panel material forming an upper support
surface of the pallet;
the pallet further comprising at least two spaced runners joined to and extending
downward from the horizontal portion for engaging the ground to space the horizontal
portion above the ground, each runner comprising at least two vertical portions of
the molded fibrous panel material arranged in parallel relation and bonded to one
another.
2. The pallet of claim 1, wherein each runner includes a separate stiffening member disposed
between and bonded to two of the vertical portions.
3. The pallet of claim 1, wherein the horizontal portion and the vertical portions are
all integrally and serially joined together along a series of spaced parallel fold
lines in the molded fibrous panel material.
4. The pallet of claim 3, wherein each fold line comprises a groove in the molded fibrous
panel material.
5. The pallet of claim 4, wherein the grooves are molded into the molded fibrous panel
material.
6. The pallet of claim 4, wherein the grooves are formed by mechanically removing fibrous
material from the molded fibrous panel material.
7. The pallet of claim 4, wherein at least some of the grooves are generally V-shaped
with an included angle of about 90 degrees between opposite side walls of the groove.
8. The pallet of claim 1, further comprising a top panel affixed atop the horizontal
portion.
9. The pallet of claim 8, wherein the top panel comprises a multi-ply laminated material.
10. The pallet of claim 9, wherein the laminated material comprises paperboard.
11. The pallet of claim 8, wherein the top panel comprises another piece of the molded
fibrous panel material.
12. The pallet of claim 11, wherein the ribs of the top panel face downward and the ribs
of the horizontal portion face upward to oppose the ribs of the top panel.
13. The pallet of claim 12, wherein the ribs of the top panel are bonded directly to the
ribs of the horizontal portion.
14. The pallet of claim 12, wherein the ribs of the top panel are joined to the ribs of
the horizontal portion via an intervening piece of sheet material disposed therebetween,
said sheet material being bonded to the ribs of the top panel and horizontal portion.
15. The pallet of claim 3, wherein the molded fibrous panel material forming the horizontal
and vertical portions comprises a single layer of the molded fibrous panel material.
16. The pallet of claim 3, molded fibrous panel material forming the horizontal and vertical
portions comprises two layers of the molded fibrous panel material joined rib-to-rib.
17. The pallet of claim 3, further comprising a reinforcing web bonded to one side of
the molded fibrous panel material along at least one of the fold lines.
18. The pallet of claim 17, wherein the reinforcing web comprises a pressure-sensitive
adhesive tape.
19. The pallet of claim 3, wherein the molded fibrous panel material has, in order, from
one end to an opposite end of the molded fibrous panel material:
first, second, and third fold lines for forming a first runner;
fourth, fifth, sixth, and seventh fold lines for forming a second runner; and
eighth, ninth, and tenth fold lines for forming a third runner.
20. The pallet of claim 1, wherein the molded fibrous panel material is formed from recycled
paper fibers.
21. The pallet of claim 20, wherein the molded fibrous panel material is impregnated with
a resin for rendering the molded fibrous panel material substantially water-resistant.
22. The pallet of claim 1, wherein each runner comprises a first pair of layers of the
molded fibrous panel material joined rib-to-rib.
23. The pallet of claim 22, wherein each runner comprises a second pair of layers of the
molded fibrous panel material joined rib-to-rib and joined to the first pair such
that the runner comprises four layers.
24. The pallet of claim 22, wherein the horizontal portion comprises a separate piece
of the molded fibrous panel material joined to the runners.