DUAL MATERIAL PALLET ASSEMBLY
FIELD AND BACKGROUND OF THE INVENTION
The present invention relates to a pallet and, more particularly, to a
pallet assembly made of two materials, each with different properties.
A pallet is a low platform on which goods are placed for storage or
shipment. A conventional pallet is typically designed to be safely lifted and
ported by a forklift. To this end, a conventional pallet typically includes
spaces adapted for receiving the fork elements of a forklift.
Old pallets were typically made of wood. However, following the
development of rigid plastic materials, and of plastic engineering nowadays
most pallets are made of plastic materials.
A typical plastic pallet typically includes two elements. The first is a
pallet top article which serves as a platform on which goods are placed,
whereas the second is pallet bottom deck (also known in the art as base
board), which is attached to the pallet top from underneath and which serves
to provide the pallet as a whole with extra strength and rigidity.
Prior art plastic pallets are characterized in that they are made of a
single plastic material. More rigid pallets are made of polycarbonate or
polyphenilin derivatives, such as polyphenilin oxide and polyphenilin ether,
having an elastic modulus in a range of 2200-3500 megapascal, whereas
weaker pallets, which are designed to carry less weight, are made of poly
polyolefin, such as polyethylene or polypropylene having an elastic
modulus in a range of 800-1500 megapascal.
Prior art plastic pallets made of a single material, polycarbonate,
polyethylene or polypropylene are disclosed, for example, in U.S. patent
Nos. 5,368,156 to Bruzzi et al., and 3,581,681 to Newton both teaching
polycarbonate pallets; 3,680,495 to Pike, teaching a polyethylene or
polycarbonate pallet; and 4,375,265 to van de Wetering et al. and 3,776,435
to Smith, both teaching polyethylene, polypropylene or polycarbonate
pallets.
Polycarbonate and polyphenilin derivatives, however, are much more
expensive as compared with polyethylene or polypropylene, yet a composite
pallet, in which some parts are made of polycarbonate or polyphenilin
derivatives, for extrarigidness, and other parts are made of polyolefin, for
cost effectiveness, were never attempted, nor were they suggested by the
prior art. For example, the market price of polyethylene or polypropylene is
in a range of about U.S. $ 0.6-1 per kilogram, whereas the market price of
polycarbonate and polyphenilin derivatives is in a range of about U.S. $ 2-3
per kilogram.
There is thus a widely recognized need for, and it would be highly
advantageous to have, a pallet in which some parts are made of
polycarbonate and/or polyphenilin derivatives for extrarigidness and other
parts are made of polyolefin, for cost effectiveness
SUMMARY OF THE INVENTION
According to the present invention there is provided a pallet
assembly comprising a pallet top article and a pallet bottom deck being
underneath and connected to said pallet top article, the pallet assembly
being made in part of a first material having an elastic module below 2000
megapascal and in part of a second material having an elastic module above
2000 megapascal.
According to further features in preferred embodiments of the
invention described below, the pallet bottom deck is selected from the group
consisting of a plurality of runners, a frame and framed runners.
According to still further features in the described preferred
embodiments the pallet top article is made of the first material, whereas the
pallet bottom deck is made of the second material.
According to still further features in the described preferred
embodiments the first material is polyolefin.
According to still further features in the described preferred
embodiments the polyolefin is selected from the group consisting of
polyethylene and polypropylene.
According to still further features in the described preferred
embodiments the second material is polycarbonate or polyphenilin
derivative, such as polyphenilin oxide and polyphenilin ether.
According to still further features in the described preferred
embodiments the pallet bottom deck is selected from the group consisting of
a plurality of runners, a frame and framed runners.
The present invention successfully addresses the shortcomings of the
presently known configurations by providing a pallet assembly which is
comparable in strength to prior art sole polycarbonate pallets on one hand,
yet is more cost-effectiveness therefrom, on the other hand.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention herein described, by way of example only, with
reference to the accompanying drawings, wherein:
FIG. 1 is a perspective view from top of an exemplary two way pallet
according to the present invention;
FIG. 2 is a perspective view from top of an exemplary four way
pallet according to the present invention;
FIG. 3 is a perspective view from below of an exemplary two way
pallet according to the present invention; and
FIG. 4 is a perspective view from below of an exemplary four way
pallet according to the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention is of a pallet assembly made of two materials,
each with different properties, which can be used for storage and shipment
of goods. Specifically, the present invention provides a pallet assembly
which is rigid enough to replace the prior art sole polycarbonate or
polyphenilin derivatives pallets yet includes polyolefin parts which render
the pallet assembly cost-effectiveness.
The principles and operation of a pallet assembly according to the
present invention may be better understood with reference to the drawings
and accompanying descriptions.
Before explaining at least one embodiment of the invention in detail,
it is to be understood that the invention is not limited in its application to the
details of construction and the arrangement of the components set forth in
the following description or illustrated in the drawings. The invention is
capable of other embodiments or of being practiced or carried out in various
ways. Also, it is to be understood that the phraseology and terminology
employed herein is for the purpose of description and should not be
regarded as limiting.
Referring now to the drawings, Figures 1-4 are illustrative examples
of two-way and four-way pallet assemblies according to the present
invention, which are referred to hereinbelow as pallet assemblies 10.
Pallet assembly 10 includes a pallet top article 12 and a pallet bottom
deck 14 being underneath and connected to pallet top article 12. According
to the present invention, pallet assembly 10 is made in part of a first
material having an elastic module below 2000 megapascal and in part of a
second material having an elastic module above 2000 megapascal.
According to the present invention pallet top article 12 is made of the
first material, whereas pallet bottom deck 14 is made of the second material.
The first material according to the present invention is polyolefin, such as,
but not limited to, polyethylene and/or polypropylene. The second material
according to the present invention is preferably polycarbonate and/or
polyphenilin derivatives, such as, but not limited, to polyphenilin oxide and
polyphenilin ether.
As specifically shown in Figures 1-2, pallet bottom deck 14 can be
either a plurality of runners 16, a frame 18 or framed runners 20, attached to
top article 12.
The specific design of top article 12 may vary to a great degree. In
the examples shown in the drawings article 12 includes top runners 22 and
legs 24. Top plates and top rib structures, as well as other designs are not
excluded. In any case, as used herein in the specification and in the claims
section below, the term "pallet top article" refers to the top and legs attached
thereto.
Pallet's 10 dimensions are preferably as set forth in ISO 6780: 1988
(E), which is incorporated by reference as if fully set forth herein.
The growth and widespread usage of pallets throughout industry has
led to the development of standards for pallet performance. ISO 8611 : 1988
entitled "general-purpose flat pallets for through transit of goods - test
methods", is an international recognized standard for flat-pallets
performances. This standard, which is incorporated by reference as if fully
set forth herein, describes a series of tests which rate a pallet's load bearing
capacity, as well as defining a safe working load. The tests have their origin
in practical experience and simulate operating realities. The following tests
are applicable to plastic pallets: bending or racking test; base board or
bottom deck test; inclined plane test; stacking test; and corner drop test.
The pallet assembly according to the present invention successfully
passed these tests for grade N (normal grade pallets), as defined in ISO TR
10232, entitled "general-purpose flat pallets for through transit of goods -
design rating and maximum working load", First Edition, November 1,
1989; and in ISO TR 10233, entitled "general-purpose flat pallets for
through transit of goods - performance requirements", First Edition,
November 1, 1989, both incorporated by reference as if fully set forth
herein.
The pallet assembly according to the present invention is unique in
that it is a composite pallet made of two materials with different properties.
The first, being more rigid, serves to provide the pallet assembly with the
required strength to render the pallet assembly according to the present
invention comparable in strength to sole polycarbonate pallets. The second
material serves to render the pallet as a whole more cost-effectiveness as
compared with sole polycarbonate or polyphenilin derivative pallets.
Although the invention has been described in conjunction with
specific embodiments thereof, it is evident that many alternatives,
modifications and variations will be apparent to those skilled in the art.
Accordingly, it is intended to embrace all such alternatives, modifications
and variations that fall within the spirit and broad scope of the appended
claims.