Patent Application
20160257444
1. Field of the Invention
The present invention is generally directed to a pallet assembly, and more particularly to a reinforced structural supporting pallet assembly having a protective polymeric coating material applied to its outer surfaces.
2. Description of the Prior Art
Generally, pallets are known to provide transport of supplies. Pallets are typically designed with apertures so that a forklift, pallet jack, front loader, or other device can be inserted underneath a top deck to lift and transport the pallet. This design allows the pallets to be easily lifted, moved, and loaded onto a transport vehicle for shipment to various facilities, points of sale, etc. Because of the usefulness of pallets, there is a constant need for improved stronger, lighter, more resilient, and less expensive pallets.
Representative examples of prior art include the following patent documents:
US Published Application Publication No. 2002/0088379 for novel pallets by inventors Phillips, et al. filed Sep. 17, 1999 and published Jul. 11, 2002 is directed to a novel pallet comprising conventional pallet coated with an elastomeric material, such as a polyurea. The invention is further directed to a novel composite pallet comprising an elastomeric material, such as a polyurea, and one or more filler materials.
US Published Application Publication No. 2006/0172074 for polyurea coating systems and related methods by inventor Diloreto filed Feb. 3, 2005 and published Aug. 3, 2006 is directed to a composition for forming a protective coating upon a substrate. The composition has been found particularly useful for forming a protective coating upon components of automotive vehicles, such as a bedliner for a pick-up truck. The composition may include, without limitation, an isocyanate component and an amine component and optionally includes one or more of a catalyst, stabilizer, pigment, fire retardant or other additives.
US Published Application Publication No. 2006/0249058 for fire resistant thermoplastic pallet by inventors Moore Jr., et al. filed Mar. 1, 2006 and published Nov. 9, 2006 is directed to a thermoplastic pallet that advantageously incorporates fire resistance by virtue of one or more of the following aspects: a sprinkler friendly deck or frame; variable fire retardant or coating distributions; fire collapsible cross beams; foam filled or foam coated parts; and pallet design, including proportioning amounts of plastic and metal utilized in construction. Exemplary combinations of features enables the pallet to meet all the dimensional, mechanical behavior and burn test requirements. The use of metal components including a corrugated aluminum deck having specially position through holes for sprinkler water, and the engineered placement of hollows in the structural plastic parts enables a reduction in the amount of plastic, and the amount of fire retardant in what plastic there is and in the pallet as a whole.
US Published Application Publication No. 2008/0156234 for co-extruded pallet block by inventor van de Camp filed Jan. 2, 2007 and published Jul. 3, 2008 is directed to a pallet block including an extruded inner core and an outer shell co-extruded with the inner core. The outer shell surrounds the inner core with respect to an extrusion axis defined by the inner core. The compositions of the inner core and outer shell differ by one or both of mass density and formula. For example, the outer shell may have a higher mass density than the inner core and may protect the inner core from impact and moisture ingression. Each of the inner core and outer shell may include product-packaging waste.
US Published Application Publication No. 2011/0005435 for wood pallet with multi-ply laminated lead boards by inventors Renck and Niu filed Jul. 9, 2009 and published Jan. 13, 2011 is directed to a wood pallet including a top deck affixed atop a plurality of spaced-apart wood spacer members such that openings for receiving tines of a forklift are defined between the spacer members. The top deck is formed by a plurality of elongate wood boards arranged parallel and side-by-side one another, the boards including two lead boards respectively located at two opposite edges of the top deck, and a plurality of intermediate boards disposed between the two lead boards. The intermediate boards are solid virgin wood boards. Each of the lead boards is a multi-ply laminated wood board made up of a plurality of wood material sheets adhesively laminated one atop another. The laminated wood boards have a capacity to withstand a greater number of edgewise forklift impacts of a given magnitude without failing, in comparison with the solid virgin wood boards.
US Published Application Publication No. 2013/0014676 for load bearing structure having antimicrobial properties by inventors Imbrecht, et al. filed Jul. 15, 2012 and published Jan. 17, 2013 is directed to a movable load bearing structure with a surface that includes antimicrobial agents capable of eliminating, preventing, retarding or minimizing the growth of microbes and also minimizing cross-contamination when the load bearing structure is being reused for cargos that differ from a previously transported cargo, for example, different food types, such as poultry, fresh vegetables, and fresh fruit. The load bearing structure may be a dunnage platform or a container for storing and/or shipping cargo.
US Published Application Publication No. 2013/0174762 for a reconfigurable load-bearing article by inventors Hedley and Bohan filed Apr. 16, 2012 and published Jul. 11, 2013 is directed to a reconfigurable load-bearing article including a deck unit and at least two supports configured to be coupled to the deck unit, the supports including at least one spacer receiving member configured to receive and releasably engage a spacer. The load-bearing article is reconfigurable to form any suitable load-bearing article and may be used to provide a lightweight, durable, strong, multipurpose pallet having a four-way forklift entry.
US Published Application Publication No. 2014/0102338 for pallets by inventor Stevens filed Apr. 4, 2012 and published Apr. 17, 2014 is directed to a method of coating wooden pallets having a low moisture content with an elastomer coating, so as to provide pallets combining the advantageous qualities of wooden and plastic pallets. The pallets are light and inexpensive, tough and durable, water and damage resistant, fire retardant and non-slip. They can be produced by treating existing wooden pallets. The pallets may also have an RFID attached before coating for tracking the pallets and goods transported thereon.
US Published Application Publication No. 2014/0141161 for a sprayable flame resistant polyurethane coating composition by inventor Bruchertseifer filed Jun. 25, 2012 and published May 22, 2014 is directed to a flexible polyurethane coating composition for application, preferably by spraying, to a substrate to protect and or improve the properties of the substrate. Specifically, the coating composition is a reactive polyurethane formulation which forms an elastomeric polyurethane coating with improved flammability properties. The reactive formulation comprises an A side comprising an isocyanate prepolymer with optional flame retardant compounds and a B side comprising a dispersion of red phosphorous, with optional additional flame retardant compounds, in an aromatic polyester polyol.
U.S. Pat. No. 3,682,110 for pallet with improved joint construction by inventor Harrison filed May 26, 1969 and issued Aug. 8, 1972 describes pallets having runners with intermediate stringers adhesively bonded to the decks.
U.S. Pat. No. 3,702,100 for a molded pallet by inventor Wharton filed Apr. 5, 1971 and issued Nov. 7, 1972 is directed to a lightweight, nestable, reusable, molded plastic pallets used for support and transport of articles stacked thereon.
U.S. Pat. No. 3,911,182 for load-supporting pallets by inventor Lieberman filed Jan. 25, 1974 and issued Oct. 7, 1975 is directed to a flat, expansible platform in the form of a rigid sandwich laminate in which the core is made of a rigid polymer material contained between top and bottom facings. At least two opposing sides of the platform are creased and slitted to form a series of integral foldable sections and constituting the expansible extent of the platform, whereby in operation the integral foldable sections are adapted to be folded over one another to complete and erect spaced parallel runners beneath the flat, expansible platform and abut the underside thereof and unfolded and expanded to return the platform to its original flat, expansible shape.
U.S. Pat. No. 4,119,205 for palletized containers by inventor Delaney filed Jul. 21, 1977 and issued Oct. 10, 1978 is directed to a palletized container including a case of folded corrugated board with strengthened parallel feet extending beneath the case to enable the container to be lifted by a fork-lift vehicle. The feet are made from lengths of corrugated board folded into a rectangular configuration and rolled around tongues which are formed from the bottom flaps of the case, thereby interlocking the case and the feet without any need for stitching or gluing of the parts. The security of the container is achieved by the interleaving of the corrugated board pieces.
U.S. Pat. No. 4,194,298 for air drying of refractory hardwoods by inventor Hart filed Jun. 2, 1978 and issued Mar. 25, 1980 describes integral wood pallets including hardwood sheets stacked between pallets.
U.S. Pat. No. 4,240,358 for wood pallet by inventor Munroe filed Feb. 22, 1977 and issued Dec. 23, 1980 describes pallets having runners with intermediate stringers and plywood-layered spacers.
U.S. Pat. No. 4,838,178 for hazardous material shipping pallet by inventors Chriske, et al. filed Jun. 2, 1988 and issued Jun. 13, 1989 describes pallets generally made from wood including sidewalls upwardly extending perpendicularly upward.
U.S. Pat. No. 5,042,396 for a plastic pallet by inventor Shuert filed Nov. 27, 1989 and issued Aug. 27, 1991 is directed to a plastic pallet in which an insert assembly is positioned within the hollow of the plastic pallet to discourage warpage and failure especially in racked, storage situations. The insert assembly includes a pair of beams arranged in an X-configuration, tower members secured at their upper ends to respective ends of the beams and positioned respectively in the four corners of the pallet, and tensioning straps extending between the tower members around the perimeter of the pallet proximate the upper surface of the bottom wall of the pallet. The X-configured beams are positioned in the space between the spaced upper and lower sheets of the platform structure of the pallet and are maintained in a convexly bowed configuration by the tensioning straps so as to resist downward bowing of the platform structure, even when the pallet is racked for extended periods of time in a loaded condition.
U.S. Pat. No. 5,237,936 for pallet and display assembly by inventor Susel filed Apr. 23, 1992 and issued Aug. 24, 1993 describes pallets generally made from wood.
U.S. Pat. No. 5,401,456 for a method of forming a plastic unit having an outer plastic shell encapsulating a foam core by inventors Alesi and Browning filed Aug. 31, 1992 and issued Mar. 28, 1995 is directed to a top sheet and a bottom sheet thermoformed about a foam core, which has feet making spaces for the tines of a fork lift truck. The top and bottom sheets meet at a line on the pallet edge to fuse and bond together and may be applied simultaneously to the core while the core is confined in a mold cavity.
U.S. Pat. No. 5,701,827 for pallet assembly by inventor Urabe filed Dec. 8, 1993 and issued Dec. 30, 1997 describes a pallet having a flat bottom deck design having support members including projections that engage holes in the flat bottom deck.
U.S. Pat. No. 5,833,207 for supports for transformers or other equipment by inventors Hagenhoff, et al. filed Oct. 21, 1996 and issued Nov. 10, 1998 is directed to a pad designed to permit multi-directional access to its underside; consequently, it need not be positioned specially once a transformer is mounted to it, but rather is accessible in almost any upright orientation to the tines of a fork-lift truck. In some embodiments the tine-receiving recesses do not abut an opening for electrical cables attached to the transformer, the opening instead being bordered by sections of the full depth of the pad. The multiple recesses of the pad thus fail to communicate with the opening, blocking any path along the underside from the periphery of the pad to the cable opening itself.
U.S. Pat. No. 6,003,448 for wooden pallets and components therefor by inventor Skuse filed Aug. 20, 1998 and issued Dec. 21, 1999 describes pallets generally made from wood having continuous stringers of laminated wood.
U.S. Pat. No. 6,418,861 for modular pallet construction by inventor Flam filed Nov. 15, 2000 and issued Jul. 16, 2002 is directed to a modular pallet construction allowing the formation of storage pallets of varying sizes and configurations. The pallet includes a top deck formed from a plurality of plate members interconnected to create a storage platform. The number and orientation of the plate members dictates the configuration of the top deck. The top deck is supported by beams which create a space beneath the top deck into which lift forks may be inserted to transport the pallet and its contents. In order to reduce the weight of the pallet yet provide ample strength, the plate members are formed with a core of high density expanded foam encapsulated in a rigid coating material.
U.S. Pat. No. 6,503,426 for a process for making foam laminates by inventor Horwitz filed Sep. 6, 2000 and issued Jan. 7, 2003 is directed to a method and apparatus for fabrication of foam laminates suitable for use in the construction of furniture and case goods are provided. The panel has an upper surface formed from a thermoplastic sheet of material such as PVC. A cavity formed by the interior surfaces of the sheet have suspended therein attachment or mounting hardware which is subsequently encapsulated by an in situ structural foaming step. The resulting laminated panel is useful as a table top, shelving, and as a structural component in a variety of case goods and furniture.
U.S. Pat. No. 6,521,298 for a process for applying polyurethane to a substrate by inventor Banks filed Mar. 11, 2002 and issued Feb. 18, 2003 is directed to a process for applying a polyurethane derived from VOC-free reactants wherein the reactants are polyol resin and isocyanate. The reactants are separately heated, proportioned and pressurized then the proportioned heated reactants are mixed together. The proportionate volume ratio of polyol resin reactant to isocyanate reactant is 1:1.05 to about 1:4. Combining the reactants initializes the formation of the polyurethane with a stoichiometric excess of the isocyanate reactant. The polyurethane reactants are sprayed onto a heated rotating substrate in an amount sufficient to create a polyurethane elastomer reinforcement layer after curing. The polyurethane reactants are polymerize or gel into an elastomer in the time range of 15 to about 120 seconds.
U.S. Pat. No. 6,613,389 for a coating process and composition for same by inventors Li, et al. filed Dec. 26, 2001 and issued Sep. 2, 2003 is directed to a composition for forming a protective coating upon a substrate. The composition has been found particularly useful for forming a protective coating upon components of automotive vehicles, such as a bedliner for a pick-up truck. The composition may include, without limitation, an isocyanate component and an amine component and optionally includes one or more of a catalyst, stabilizer, pigment, fire retardant or other additives.
U.S. Pat. No. 7,297,372 for a coating process and composition for same by inventors Li, et al. filed Jun. 27, 2003 and issued Nov. 20, 2007 is directed to a composition for forming a protective coating upon a substrate. The composition has been found particularly useful for forming a protective coating upon components of automotive vehicles, such as a bedliner for a pick-up truck. The composition may include, without limitation, an isocyanate component and an amine component and optionally includes one or more of a catalyst, stabilizer, pigment, fire retardant or other additives.
U.S. Pat. No. 8,181,580 for a composite structural material and method of making the same by inventors Roth and Palmer filed Dec. 29, 2005 and issued May 22, 2012 is directed to a composite structural material suitable, for example, as a replacement for wooden boards, sheets, or posts, is disclosed. It includes a dimensionally stable core material substantially surrounded by a dimensionally stable, laminar covering that is adherent to the core material.
U.S. Pat. No. 8,567,324 for foam pallets and methods of constructing by inventors Paradis, et al. filed Oct. 9, 2012 and issued Oct. 29, 2013 is directed to an exemplary pallet including a composite board having a foam core and a facer material coupled therewith. The composite board may define a roughly flat top surface that is configured to support one or more goods or other objects placed thereon. A plurality of composite blocks having a foam core and a facer material coupled therewith may be coupled with a bottom surface of the composite board to support the composite board above the ground. The plurality of composite blocks may also be arranged with respect to the bottom surface to allow forks of a fork lift to be positioned under the bottom surface of the composite board so that the pallet may be lifted and/or transported via the forklift.
Most recently, plastics have been used to produce pallets; however, the benefits of using wood still substantiate their use. Benefits of using wood to produce pallets are that wood 1) has a high coefficient of friction, which affords stability to an item while on a pallet and to a pallet while being transported on a forklift, 2) is a renewable and recyclable resource, 3) is easily reparable, and 4) can hold a large amount of weight (>1500 lb). Pallet production with wood is less expensive than plastic. Wood pallets are made from wood that was not harvested from a newly timbered tree, thus allowing for more efficient consumption of natural resources. Because wood is a natural resource, less energy is needed to produce a wooden pallet compared to a plastic pallet. On the contrary, a wood pallet gives off moisture, splinters, harbors bugs and mold, and is a fire hazard; a remedy to these downsides includes applying a polymeric coating to the entirety of a wood pallet. Moreover, wood may need fasteners, which can damage materials; use of adhesives is a way around this damage. With the pros and cons of both wood and plastic pallets described in the prior art, a pallet that incorporates the benefits of both may be a more acceptable alternative.
The present invention is directed generally to an improved pallet assembly and methods of making same. More particularly, the present invention is directed to a reinforced structural supporting pallet assembly having a protective non-pigmented or non-contaminant polymeric coating material applied to its outer surfaces. In one embodiment, the present invention provides a reinforced pallet, which is constructed generally of wood, includes a substantially planar top platform, a plurality of spacers to provide apertures for a forklift, bottom runners, and is coated or completely encapsulated by a polymeric (polyurea) material, preferably applied in a substantially uniform spray coating. The spacers may further include a foam core to reduce pallet weight but not compromise strength. The bottom runners provide structural reinforcement for enhanced overall pallet stability and strength. The polymeric material is preferably a non-pigmented polyurethane that provides a predetermined surface friction, resistance to surface damage, and overall integrity, while not introducing a contaminant surface that would prohibit food contact therewith.
In a preferred embodiment, a cross member is inserted into the core layer of the platform to provide reinforcement and increased strength to the platform for supporting a load placed thereon, i.e., under heavy cargo applied weight.
In one example, the present invention provides a hybrid wood/plastic pallet, including a unitary flat top deck surface with a foam core layer and a laminate outer layer. A wood cross member is positioned in the core layer, wherein the cross member fixedly connects to diagonally opposing corners of the top deck perimeter and crosses at the center of the pallet core layer horizontal plane. The core layer and cross member are completely surrounded by the laminate outer layer creating a laminate-core-laminate sandwich top deck. The unitary flat top deck is connected to a plurality of bottom support runners by a plurality of spacers. The plurality of spacers are fixedly, adherently connected to the top deck and the bottom support runners, and the spacers are wood but contain a central core hole, wherein the core hole is foam filled and centrally positioned through the long axis of the spacer, perpendicular to the horizontal planes of the top deck and plurality of bottom runners. The plurality of bottom runners form a bottom perimeter and include a center runner parallel and equidistant to the long edges of the perimeter creating a three-runner bottom. A plastic spray coating completely, adherently encapsulates the entire hybrid pallet. The flat top deck provides high friction. The cross member is stiff and provides support. The plurality of bottom runners are wood and provide support when the pallets are stacked. The plastic spray coating is thinly applied, provides additional friction, affords abrasion resistance, and is preferably non-pigmented or includes some pigmentation that is not considered a contaminant for foods, thereby allowing contact with food or food product placed directly on the platform surface without introducing contamination to the food or food product.
In a preferred embodiment, a cross member is inserted into the core layer of the platform to provide reinforcement and increased strength to the platform for supporting a load placed thereon, i.e., under heavy cargo weight.
These and other aspects of the present invention will become apparent to those skilled in the art after a reading of the following description of the preferred embodiment when considered with the drawings, as they support the claimed invention.
Referring to the drawings in general, the illustrations are for the purpose of describing a preferred embodiment of the invention and are not intended to limit the invention thereto.
The present invention provides a reinforced structural supporting pallet assembly having a protective non-pigmented or non-contaminant polymeric coating material applied to its outer surfaces. In one embodiment, the present invention provides a reinforced pallet, which is constructed generally of wood, includes a substantially planar top platform, a plurality of spacers to provide apertures for a forklift, bottom runners, and is coated or completely encapsulated by a polymeric (polyurea) material, preferably applied in a substantially uniform spray coating. The spacers may further include a foam core for reduced pallet weight but not compromised or decreased strength. The bottom runners provide structural reinforcement for enhanced overall pallet stability and strength. The polymeric material is preferably a non-pigmented polyurethane that provides a predetermined surface friction, resistance to surface damage, and overall integrity, while not introducing a contaminant surface that would prohibit food contact therewith.
The present invention provides a hybrid pallet, including components of different materials, by way of example and not limitation, wood and plastic components, for a lightweight and strong pallet. As shown in
The following description describes a pallet assembly having a generally planar top platform, which is multi-layered and with its components unitarily integrated. The multiple layers include a core layer and outer layers (top and bottom outer layers) on opposite sides of the core layer. The core layer includes an expanded polystyrene (EPS) foam or other suitable lightweight material, and the laminate layers are preferably formed of a wood laminate. A top surface on one side of the laminate is the most superficial layer and provides a contact surface that does not contain contaminants that may directly contact pallet cargo. Spacer blocks separate a bottom plurality of runners, which form a perimeter base of the core layer. The pallet is coated with a coating material, preferably a synthetic polymeric material, and the sum of the pallet components and coating combined preferably weighs less than about 40 lb. In another embodiment, the pallet is coated with a coating material, preferably a synthetic polymeric material, and the sum of the pallet components and coating combined preferably weighs less than about 50 lb. The polymeric material is preferably a non-pigmented (or non-contaminant pigmentation) polyurea hybrid that provides a predetermined surface friction, resistance to surface damage, and overall integrity, while not introducing a contaminant surface that would prohibit direct food contact therewith. In addition, the pallet can also be coated with a fire retardant chemical. Preferably, the fire retardant chemical is incorporated into the polymer spray coating.
The following description is provided for exemplary and preferred embodiments for a pallet assembly of the present invention. In one embodiment, a top platform perimeter is constructed and configured to a predetermined size suitable for supporting and transporting goods thereon. The top platform perimeter is about 40″× about 48″ according to dimensions of a short edge and a long edge with spaced apart parallel corresponding edges, respectively, and wherein the perimeter members are formed of knotty pine or other suitable, lightweight, impact resistant, strong wood or composite material. In one embodiment, the wood includes members that are about 1″× at least about ¾″ thick, more preferably about 1″× about 1″ thick. Furthermore, the top platform includes a core material encapsulated by laminate outer layers, wherein the core layer is made of expandable polystyrene (EPS) foam (25 PSI) or other suitable lightweight material, and the laminate outer layers are formed of hardwood and approximately 2.7 mm thick; wood laminate is known in flooring production, but its use in pallet production is limited. Inserted into the core layer is a cross member (also referred to as “X” or “X-member”) fixedly connecting to diagonally opposing corners. The “X” is approximately 1″×¾″ thick, more preferably 1″×1″ thick. The “X” is inserted into the core layer, whereby the EPS foam is divided into four triangular areas, wherein the EPS foam is a rigid, foamed plastic that confers water resistance, physical strength, and dimensional stability. A preferred EPS foam is the Type I 1.0 commercially manufactured by Cellofoam, but may be another Type as shown in
In a preferred embodiment, as shown in
In a preferred embodiment, bottom runners are about 0.5″ thick knotty pine or other suitable wood or composite material and form a perimeter along the short edge and long edge as the base of the pallet, wherein the short edge runners are about 4.5″ wide and about 40″ long, the long edge runners are about 5″ wide and about 39″ long, and a center runner is about 4.5″ wide and about 39″ long, wherein the center runner runs parallel and equidistant to the long edges and extends between the middle points of the short edge. The bottom runners connect to the spacer blocks by way of screws and/or adhesive.
In another embodiment, the top platform is approximately 40″×48″ according to the short edge and long edge, respectively, and wherein the perimeter members are knotty pine or other suitable wood or composite materials and about 1″× at least about ¾″ thick. The top platform core material is made of EPS foam (25 PSI) or other lightweight material, and the laminate outer layers are formed of hardwood and approximately 5 mm thick. No “X” member is inserted in the core layer, thus the EPS foam completely fills the core layer.
In an alternative embodiment, spacer blocks are positioned between the top platform and the bottom runners, wherein the spacer blocks are located at each perimeter corner, each mid-point on each edge of the perimeter, and exactly in the center of the bottom platform. The position of the spacer blocks determines the size of the block, wherein large blocks are at the perimeter corners and small blocks are at the other positions. Large spacer blocks are preferably of wood, about 3.5″ tall, and about 6″× about 4.5″ in perimeter. Preferably, the large spacer blocks contain holes that penetrate about 2.5″ deep from the upper surface, leaving a 1″ thick solid base, and are about 2.5″× about 5″ with about 1.25″ radius fillets on the vertical corners, wherein the holes are filled with lightweight foam to decrease overall pallet weight. Small spacer blocks are preferably of wood, about 3.5″ tall, and about 3.5″× about 4.5″ in perimeter. Preferably, the small spacer blocks contain holes that penetrate about 2.5″ deep from the upper surface, leaving about 1″ thick solid base, and are about 1.5″× about 2.5″ with about 0.75″ radius fillets on the vertical corners, wherein the holes are filled with lightweight foam to decrease overall pallet assembly weight while maintaining strength or pallet compression or deflection resistance under load.
In another embodiment, a three-runner pallet is provided, wherein the plurality of bottom runners form a perimeter along the short edge and long edge as the base of the pallet, wherein the perimeter runners are wood, about 4.5″ wide and about 0.5″ thick, and a center runner runs parallel and equidistant to the long edges and extends between the middle points of the short edges, wherein the center runner is formed of wood, about 5″ wide and about 0.5″ thick.
In an alternative embodiment, the top platform is approximately 40″×48″ according to the short edge and long edge, respectively, and wherein the perimeter members are wood and about 1″× about 1″ thick. The top platform core material is made of EPS foam (25 PSI) or other lightweight material, and the laminate outer layers are hardwood and approximately 5 mm thick. Inserted into the core layer is a cross member “X” connecting diagonally opposing corners. The “X” is approximately 1″×1″ and of wood. The “X” is included in the core layer, whereby the EPS foam is divided into four triangular areas and separated by the cross member that forms the “X”. The “X” pieces may be cut to facilitate cross-lap at the center spacer block.
In an alternative embodiment, the top platform is approximately 40″×48″ according to the short edge and long edge, respectively, and wherein the perimeter members are formed wood and about 1″× about 1″ thick. The top platform core material is made of EPS foam (25 PSI) or other lightweight material, and the laminate outer layers are hardwood and approximately 2.7 mm thick. No “X” member is inserted in the core layer, thus the EPS foam completely fills the core layer.
In another embodiment, the upper laminate layer of the top platform is about 2.7 mm and the bottom laminate layer is about 5.0 mm. The “X” member is about 1″ thick, and the large blocks are about 7″ long to provide more surface area contact for adhesion with the bottom runners and with the “X” member(s). In an alternative embodiment, adhesion or at least contact with the surface is enhanced by creating “L” shaped butting ends between the long and short edge bottom runners, wherein the “L” abutment is affixed to the bottom of the spacer block.
In an alternative embodiment, the upper laminate layer of the top platform is about 2.7 mm and the bottom laminate layer is about 2.7 mm. The “X” member is 1″ thick. In another embodiment, adhesion is enhanced by creating “L” shaped butting ends between the long and short edge bottom runners, wherein the “L” abutment is affixed to the bottom of the spacer block. An alternative to the traditional perimeter base of the bottom may be a non-perimeter, three-runner base measuring about 40″ in length.
In another embodiment, the top platform is continuous and minutely convexly shaped to help drain water and reduce flexion. The flat top platform may include drainage holes, which may be configured in a predetermined pattern, size, position, number, and combinations thereof. In one embodiment, the flat top platform includes 8 drainage holes. In an alternative embodiment, the rigid EPS foam core may have various densities of foam depending on the load-bearing use of the pallet, such that different pallets are made for different ranges of material weight; the pigment (or preferably non-pigment) of the polymer coating may differentiate the load range, wherein any pigmented material will not contaminate or be considered a contaminant for food items having direct contact with the pallet surface.
In an alternative embodiment, the spacer blocks are completely formed of the high-density, lightweight foam and are surrounded by the same laminate used for the outer layers of the top platform. In yet another embodiment, the spacers are formed completely of wood, preferably a lighter weight wood, such as by way of example and not limitation, knotty pine, balsa, or cedar. The wood includes hardwood. In yet another embodiment, the spacer blocks are between about 1″ to about 3.5″ tall, allowing for more pallets to be stacked in a given area, while still creating apertures tall enough to accept forklift tines inserted therein. The large spacer blocks have perimeter dimensions of between about 6.0 and about 9.0″× between about 4.5 and about 6.8″, and the small spacer blocks have perimeter dimensions of between about 3.5 and about 4.7″× between about 4.5 and about 6.0″. The larger spacer block dimensions provide more surface area for top platform and bottom runner adherence and greater structural support.
In another embodiment, the bottom runners are surrounded by laminate outer layers similar to those of the top platform. In an alternative embodiment, the bottom runners are formed of high-density, lightweight foam and include laminate outer layers similar to those of the top platform. In yet another embodiment, the bottom runners are hardwood. The bottom runners are attached to the spacer blocks by adhesive.
The present invention provides a pallet assembly with a thinly-applied polymeric spray coating to produce a substantially uniform thin coating over the surface of the pallet, preferably a polyurea hybrid (PUH). Polyurea has a very high shore hardness rating; ratings of approximately 90 have been observed, which is harder than a hard hat (typically 80 shore). Furthermore, polyurea has a high tensile strength of greater than 1900 psi. The amount of polymer sprayed to the weight of pallet preferably is approximately about 1 lb of polymer to between about 5 and about 6 lb of pallet, wherein the overall polymer thickness is between about 1 mm and about 1.5 mm, and wherein the overall pallet weight is between about 30 lb and about 40 lb. In another embodiment, the amount of polymer sprayed to the weight of pallet preferably is approximately about 1 lb of polymer to between about 5 and about 6 lb of pallet, wherein the overall polymer thickness is between about 1 mm and about 1.5 mm, and wherein the overall pallet weight is between about 30 lb and about 50 lb. The polymer may be pigmented any color, but preferably is non-pigmented. The lack of pigmentation of the polymer results in a pallet that is potentially rated for direct food contact. In an alternative embodiment, the plasticized spray coating may be of another suitable polymer, such as polyurethane. An alternative polymer may be a blend of suitable polymers, such as, by way of example and not limitation, a polyurea/polyurethane blend, which cures quickly and has excellent adhesion to various surfaces, such as wood, laminate, and foam. A preferred blend formulation is provided commercially by BASF in Elastocast S55090, wherein the resin and isocyanate mix together to form a protective, abrasive (to provide friction), impact-resistant coating. In an alternative embodiment, a preferred blend formulation includes elastomer polyurethane/polyurea which has a density of about 70 pcf (via ASTM-D-1622), has a hardness of about 45 shore “D (via ASTM-D-2240), has an abrasion resistance of about 0.10% taber per 1000 cycles (via ASTM-D-4060), has a tensile strength of about 1800 psi (via ASTM-D-2370), has an elongation percentage of about 115 (via ASTM-D-2370), and/or has a tear resistance of about 304 pli (via ASTM-D-1004) when in solid form at about 75 degrees Fahrenheit. In an alternative embodiment, a preferred liquid blend formulation includes an A (iso) component and a B (polyol) component. The A component has a viscosity of about 600+/−100 cps in iso form (via ASTM-D-1638/D-4878) and has a specific gravity of 1.15 gr/cc (via ASTM-D-1638/D-4878). TheB component has a viscosity of about 1100+/−100 cps in iso form (via ASTM-D-1638/D-4878) and has a specific gravity of 1.08 gr/cc (via ASTM-D-1638/D-4878). In an alternative embodiment, a spray material is provided according to U.S. Pat. Nos. 6,613,389 and 7,297,372 and US patent pending 20140141161, which are each incorporated by reference herein in their entirety. Additionally, a method for coating pallets is provided in US patent application 20140102338, which is incorporated by reference herein in its entirety. The polymer application creates a nonporous, waterproof surface compared to the porous nature of wood. The polymer application also helps reduce the amount of styrene particles in customer locations after damage events occur. Furthermore, the pallet can also be coated with a fire retardant chemical. Preferably, the fire retardant chemical is incorporated into the polymer spray coating.
The hybrid pallet embodiments and other pallet embodiments described herein within the scope of the present invention meet or exceed standards test results required for pallets and related structures employed in materials handling and shipping based on Active Standard ASTM D1185-98a (2009), which is hereby incorporated by reference in its entirety. The wood and plastic components used in pallet assembly meet or exceed ASTM Wood standards and ASTM Plastics standards. ASTM Wood standards include D2555-06 (2011) and D3043-00 (2011), which are herein incorporated by reference in their entirety, and ASTM Plastics standards include D732-10, D952-10, D953-10, D4508-10, D1621-14, D648-07, D5672-09, and D1894-14, which are herein incorporated by reference in their entirety. The embodiments and others within the scope of the present invention meet or exceed testing standards provided by the International Organization for Standards (ISO). ISO Plastics in general (83.080.01) and ISO Wood, sawlogs, and sawn timber (79.040) testing standards are hereby incorporated by reference in their entirety.
Coefficient of friction. In a preferred embodiment, when a 44-lb water bottle is placed on the top and edge of a pallet, and the opposite edge of the pallet is raised to tilt the pallet at an angle, a vertical displacement of approximately about 16″ to about 21″ is needed for the water bottle to slide off the pallet platform. In another embodiment, when a 44-lb water bottle is placed on the top and edge of a pallet, and the opposite edge of the pallet is raised to tilt the pallet at an angle, a vertical displacement of approximately about 16″ to about 24″ is needed for the water bottle to slide off the pallet platform. In comparison, a non-coated plastic pallet only requires a vertical displacement of approximately about 10″ to about 13″ for the 44-lb water bottle to slide off of the pallet platform, wherein the non-coated pallet does not include the polymeric coating. Therefore, the coefficient of friction of the coated pallet is greater than that of a non-coated plastic pallet. Further, when 4 bags of coffee (totaling 500 lb) are placed on the top platform of the pallet, and the pallet is driven by a forklift 2′ above the ground for approximately 6′ at 4 mph and then stopped immediately, the pallet slides on the forklift tines approximately about 3″ to about 6″. In another embodiment, when 3 bags of coffee (totaling 450 lb) are placed on the top platform of the pallet, and the pallet is driven by a forklift 2′ about the ground for approximately 6′ at 4 mph and then stopped immediately, the pallet slides on the forklift tines approximately about 1″. In comparison, a non-coated wooden pallet slides on the forklift tines approximately about 10″ to about 12″, wherein the non-coated pallet does not include the polymeric coating. Therefore, the coated pallet is superior to the non-coated wooden pallet.
Static deflection. In general for prior art pallets, when 3,100 to 3,400 lb load is placed directly on top of a stacked pallet, the prior art pallet platform should deflect downward only about ¼″ to about 1″. Advantageously, for a preferred embodiment of the present invention, when a 3,750 lb load is placed directly on top of a pallet, the pallet platform maximally deforms or deflects downward approximately 4 mm. The unloaded maximum deformation may be approximately 1.5 mm. With a 3,100 lb load placed on top of the pallet in 104° F. for 24 h, the maximum deflection at the middle spacer block may be about 0.5″ to about 0.83″; unloaded maximum deflection may be about 0.3″. With a 5,000 lb load placed on top of the pallet in 104° F. for 24 h while the pallet is supported across the center of the pallet, the maximum deflection may be approximately about 1/16″ to about ¼″, and on a flat surface the maximum deflection may be approximately ⅛″. In an alternative embodiment, the top surface of the pallet is formed of plywood having a thickness of about 7/16″. When a 2,000 lb load is placed directly on top of the pallet, the pallet platform deflects approximately equivalent to or lesser than a non-coated wooden pallet formed of plywood having a thickness between about ½″ to about 11/16″, wherein the non-coated pallet does not include the polymeric coating. Therefore, the coated pallet creates a much sturdier board when compared to a non-coated pallet.
Dynamic Strength Test. In a preferred embodiment, when a pallet is raised to heights of about 3′ and dropped directly on its corner 3 successive times to gauge any damage that occurs, the pallet drops result in little to no visible damage. In an alternative embodiment, when 8 bags of coffee (totaling 1000 lb) are placed on a pallet and then the corner blocks of the pallet are hit with forklift tines at various angles, the pallet receives no visible damage. In an alternative embodiment, when a pallet is placed against a pole and therefore unable to move after being hit by the forklift, the pallet is damaged but results in a sliced wooden block that is both load bearing and usable. In comparison, when this test is performed with a non-coated wooden pallet, wherein the non-coated pallet does not include the polymeric coating, the non-coated pallet is destroyed and is neither load bearing nor usable. With a pallet stored at −28° F. for 24 h and then dropped three times from a height of about 1 yd, the post-drop diagonal length may differ from the pre-drop diagonal length by no more than approximately 1/16″. A pallet stored at −28° F. for 24 h with a load of about 880 lb and run into a stop at about 2 mph on both the long and short edge twice each may reveal no cracks and/or no greater than about 1.5% deformation on the long edge. A pallet stored at −28° F. for 24 h with a load of about 440 lb and run into a stop at about 2 mph on a corner spacer block may reveal no cracks.
Certain modifications and improvements will occur to those skilled in the art upon a reading of the foregoing description. By way of example, while knotty pine wood was specified as one embodiment, other wood types such as plywood may be used as suitable replacements for providing lightweight, strong pallets as described hereinabove. Additionally, advantageously, the non-pigmentation may be provided to eliminate visual indication of chipping or wear of the coating, which may reduce the commercial value of the pallet. Furthermore, advantageously, having an all wooden structure inner frame and simplified top deck allows manufacturing of the entire pre-sprayed pallet at a single lumber mill, which saves both time and money. The above mentioned examples are provided to serve the purpose of clarifying the aspects of the invention and it will be apparent to one skilled in the art that they do not serve to limit the scope of the invention. All modifications and improvements have been deleted herein for the sake of conciseness and readability but are properly within the scope of the present invention.
This application claims priority from U.S. Provisional Patent Application No. 62/127,390, filed Mar. 3, 2015, which is incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 62127390 | Mar 2015 | US |
