Horizontally supported planar surfaces – Industrial platform – Having plastic load-contacting surface
Reexamination Certificate
2000-02-28
2002-09-10
Cuomo, Peter M. (Department: 3636)
Horizontally supported planar surfaces
Industrial platform
Having plastic load-contacting surface
C108S902000, C108S056300, C108S053300
Reexamination Certificate
active
06446563
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to pallets and shipping trays, and more particularly to improved load bearing pallets and shipping trays comprising thermoplastic material.
2. Description of Related Art
Many wooden and plastic pallets are known in the art. However, pre-existing wooden and plastic pallets are characterized by a number of disadvantages. Wooden pallets are relatively heavy and difficult to manufacture. Typical construction of such pallets utilize a first set of parallel boards forming an upper surface, and a second set of parallel boards forming a lower surface, nailed to three or more stringers positioned perpendicular to the length of the boards, and sandwiched between the upper and lower surfaces. The stringers used to separate the upper and lower deck surfaces create two openings to accommodate the arms of a forklift for lifting and moving the pallets. The wood used to construct the pallets may swell and warp if exposed to moisture. Wooden pallets are subject to rotting and splintering, and the wood may be a substrate for the growth of fungus and bacteria, especially under moist conditions. The nails used in the pallets may rust, and sometimes causes cargo damage or injuries.
Attempts to form pallets from other materials in order to avoid the disadvantages inherent in wooden pallets have been only partially successful. Prior art designs using plastics to form pallets have been characterized by a trade off between cost and weight bearing capability. Those pallets having a significant weight bearing capability tend to be heavy and expensive, whereas plastic pallets produced inexpensively typically have reduced durability and weight bearing capacity.
What is needed is a pallet design comprising a plastic material that overcomes the disadvantages of the prior art. Specifically, it is desirable to provide a pallet that is inexpensive and relatively light weight yet strong, that is formed of recyclable materials, that is stackable, that may be readily assembled on site, that may be picked up by a fork lift from all four sides, that is resistant to the growth of fungus and bacteria, and that is easily cleaned.
SUMMARY OF THE INVENTION
Accordingly, the invention is an improved load bearing pallet including at least an upper deck formed of a sheet of rigid but formable material, such as plastic or metal but preferably a thermoplastic material, with a load engaging surface on one side of the sheet and a lift engaging surface on the other. A number of features such as ridges, channels, depressions, and legs are formed in the sheet with corresponding features being defined by the sheet on the opposite side. The pallet preferably includes a peripheral channel formed around a periphery of the upper deck and nine legs positioned in three rows of three creating two gaps on each side of the pallet for the tines of a fork lift to enter to lift the pallet.
In a second embodiment, the pallet may further include at least one integral reinforcing member received within the peripheral channel. Preferably one reinforcing member is positioned within the peripheral channel on each side of the pallet, but in alternate embodiments, a unitary ring that fits around the pallet, but within the peripheral channel, may be used. The reinforcing members may be formed of any desired materials, including metal or wood. However, the reinforcing members preferably comprise a steel support structure encapsulated within a thermoplastic material. The reinforcing members are preferably bonded within the channel of the upper deck by causing the molecular structure of the thermoplastic material encapsulating the support structure to cross-link with the thermoplastic material comprising the upper deck to integrally bond the reinforcing member to the upper deck to form a unitary object.
In other embodiments, the pallet may further include a lower deck or other support structure. The lower deck is preferably formed of a single sheet of rigid but formable material, preferably a thermoplastic material, comprising a top surface and a bottom surface. A plurality of legs are formed in the top surface of the lower deck, corresponding to an equal number of legs extending from the lifting surface of the upper deck. Each leg formed in this way in the lower deck is coupled to a corresponding leg of the upper deck. The bond between the legs of the lower deck and the legs of the upper deck are preferably made by causing the molecular structure of the thermoplastic material of the upper deck to cross link to the molecular structure of the lower deck, although in alternate embodiments, other means for coupling the upper and lower decks may be used.
The lower deck may further include a plurality of channels and ridges formed in the top surface of the lower deck, which correspond to channels and ridges formed in the bottom surface. The lower deck may additionally include a plurality of reinforcing members, each preferably comprising a steel support structure encapsulated within a thermoplastic coating, although other materials may be used in alternate embodiments. The reinforcing member is received within the peripheral channel of the lower deck and is preferably bonded therein by causing the molecular structure of the thermoplastic material encapsulating the support structure to cross link with the molecular structure of the thermoplastic material of the lower deck.
The invention further includes a single deck pallet with runners. Such a pallet comprises a single sheet comprising a rigid but formable material, a load bearing surface on a first side of the sheet, and a lifting surface on an opposite second side of the sheet. A plurality of depressions are formed in the load bearing surface corresponding to an equal number of legs extending from the lifting surface. A runner is coupled to at least two of the legs. The lifting surface is substantially parallel to the load bearing surface such that features defined in the load bearing surface will have a corresponding feature defined in the lifting surface. Thus, a plurality of top channels and top ridges are formed in the load bearing surface wherein each top ridge formed in the load bearing surface corresponds to a bottom channel formed in the lifting surface and each top channel formed in the load bearing surface corresponds to a bottom ridge formed in the lifting surface.
The single sheet has four edges defining a periphery. A peripheral channel is formed adjacent to the periphery of the sheet. The rigid but formable material of the sheet comprises a thermoplastic material. The runner is coupled to one of the rows of three legs. The plurality of depressions comprises nine depressions corresponding to nine legs, the nine depressions and legs being disposed in three rows with each row having three depressions and three corresponding legs. The runner has a substantially flat upper and lower surface. The runner comprises wood or any other solid material. The runner comprises a thermoplastic covering.
At least two of the legs which are coupled to the runner each comprise a recessed portion and an exposed portion. The runner may have a flat bottom runner surface as well as a flat top runner surface. The runner is disposed in the recessed portions of the at least two of legs such that the bottom runner surface is substantially flush with the exposed portions of the at least two legs. Furthermore, the runner may be removably coupled to at least two of the legs with a locking pin or any other securing mechanism.
The invention further comprises a pallet made of two sheets, or a dual deck pallet. A first sheet, or upper deck, is coupled to a second sheet, or lower deck, to form the single pallet. The second sheet may have a structure that is substantially similar to or different from a structure of the first sheet. If the sheets are identical or substantially similar in structure, the first sheet may be nested on top of the second sheet when the pallet is disassembled and not in use. If the sheets are different in structu
Andras Joseph C.
Cuomo Peter M.
Lin Vic Y.
Myers Dawes & Andras LLP
Tran Hanh V.
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