Patent Publication Number: US-11027881-B2

Title: Plastic pallet having an integrally formed deck and method of manufacturing the same

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a non-provisional application claiming priority from U.S. Provisional Application Ser. No. 62/712,272, filed Jul. 31, 2018, and incorporated herein by reference in its entirety. 
    
    
     FIELD OF THE DISCLOSURE 
     The present description relates generally to plastic pallets and more particularly to a plastic pallet having an integrally formed injection molded deck and method of manufacturing the same. 
     BACKGROUND OF RELATED ART 
     Various plastic pallets are well known in the art. For example, EP 2628686 describes a pallet and a method for assembling and disassembling a pallet formed of two identical plastic material half pallet members assembled to each other in face to face relationship by interlocking snap-fit latches. Each half pallet includes a first row of hollow posts disposed on its first lateral side, a second row of support legs disposed on its second lateral side and a third central row of half hollow posts integral with half support legs disposed opposite to the half hollow posts with regard to said central axis of the pallet. The snap-fit latches are formed by protruding parts arranged to snap in corresponding holes and are disconnectable with a tool. 
     In another example, U.S. Pat. No. 8,943,981 describes a reinforced plastic pallet including a top deck and a bottom deck supported in spaced apart relationship by a plurality of post assemblies. A reinforcement assembly is encapsulated within at least one of the top or bottom deck. The reinforcement assembly includes at least one reinforcement rod having opposed ends and a plurality of reinforcement caps. 
     Finally, in another example, U.S. Pat. No. 8,584,599 describes a plastic pallet that is formed from two pieces, namely a base and a deck that can be coupled to each other with fasteners therebetween. The base and deck are provided with posts each projecting in a direction towards the other and able to be coupled to each other in order to form hollow columns. The posts projecting from the base form the outer wall of a plurality of columns, and the posts projecting from the deck are located at the interior of the columns, forming the inner wall thereof and thus constituting a hollow passage between the outer and inner walls of the columns. The hollow space is filled up with a foamed material to provide a greater impact resistance and resistance to disassembly under normal conditions of operation. 
     While the above pallets may be generally suitable for their intended purposes, there is an identifiable need for an improved plastic pallet construction with a unitary deck as disclosed herein. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a top, perspective view of an example plastic pallet constructed in accordance with the teachings of the present disclosure. 
         FIG. 2  is a bottom, perspective view of the example pallet of  FIG. 1 . 
         FIG. 3  is an exploded, perspective view of the example pallet of  FIG. 1 . 
         FIG. 4  is a top, perspective view of an example integrally formed injection molded deck for use in the example pallet of  FIG. 1 . 
         FIG. 5  is a bottom, perspective view of the example integrally formed injection molded deck of  FIG. 4 . 
         FIG. 6A  is a top plan view of an example bottom sheet for use in the example pallet of  FIG. 1 . 
         FIG. 6B  is an enlarged cross section of the example bottom sheet of  FIG. 6A  as assembled with the example deck of  FIG. 4 . 
         FIG. 7A  is a top plan view of an example top sheet for use in the example pallet of  FIG. 1 . 
         FIG. 7B  is a perspective view of the top sheet of  FIG. 7A . 
         FIG. 7C  is an enlarged cross section of the example top sheet of  FIG. 7A  as assembled with the example deck of  FIG. 4 . 
         FIG. 8A  is a top, perspective view of the example deck of  FIG. 4 . 
         FIG. 8B  is an enlarged cross-sectional view of the example deck taken along rectangle A-A of  FIG. 8A . 
         FIG. 9A  is a bottom, perspective view of the example deck of  FIG. 4 , showing the location of various radiused perimeters. 
         FIG. 9B  is an enlarged cross-sectional view of the identified radiused perimeters of  FIG. 9A . 
         FIG. 10  is an exploded perspective view of the example deck of  FIG. 4  including example reinforcement rods. 
         FIG. 11A  is a perspective view of one of the example reinforcement rods of  FIG. 10 . 
         FIG. 11B  is an end elevational view of the example reinforcement rod of  FIG. 11A . 
         FIG. 12  is an illustration of an example method of manufacturing the top sheet and bottom sheet of the example pallet. 
         FIG. 13  is an illustrated example step in the method of injection molding the deck. 
         FIG. 14  is another example step in the method of injection molding the deck. 
         FIG. 15  is another example step in the method of injection molding the deck. 
         FIGS. 16A-16C  together illustrate another example manufacturing step of the deck. 
         FIGS. 17A-17B  together illustrate another example manufacturing step of the deck. 
         FIG. 18  is an illustration of an assembly step of the pallet showing the reinforcement rod placement. 
         FIG. 19  is an illustration of an assembly step of the pallet showing the welding of the top sheet. 
         FIG. 20  is an illustration of an assembly step of the pallet showing additional reinforcement rod placement. 
         FIG. 21  is an illustration of an assembly step of the pallet showing the welding of the bottom sheet. 
         FIG. 22  is a top, perspective view of an example plastic pallet constructed in accordance with the teachings of the present disclosure. 
         FIG. 23  is a bottom, perspective view of the example pallet of  FIG. 22 . 
         FIG. 24  is a top, perspective view of an example integrally formed injection molded deck for use in the example pallet of  FIG. 22 . 
         FIG. 25  is a bottom, perspective view of the example integrally formed injection molded deck of  FIG. 24 . 
         FIG. 26  is another top, perspective view of the example deck of  FIG. 24 . 
         FIG. 27  is an enlarged cross-sectional view of the example deck taken along line  27 - 27  of  FIG. 26 . 
     
    
    
     DETAILED DESCRIPTION 
     The following description of example methods and apparatus is not intended to limit the scope of the description to the precise form or forms detailed herein. Instead the following description is intended to be illustrative so that others may follow its teachings. 
     Referring now to  FIGS. 1-11B , an example plastic pallet  10  is illustrated and disclosed.  FIGS. 1 and 2  illustrate a top and bottom perspective view of the fully assembled pallet  10 . As disclosed, the example plastic pallet  10  has an integrally formed deck  12 . More precisely, as illustrated in  FIG. 3 , the example plastic pallet includes the deck  12 , a top reinforcement rod assembly  14 , a top sheet  16 , a bottom reinforcement rod assembly  18 , and a bottom sheet  20 . In the present example, the deck  12  is molded as a single monolithic member and more precisely, the example deck  12  is a single piece injection molded deck. 
     As completely assembled, the pallet  10  is fully encapsulated and is compliant with NSF International standards. By being encapsulated, the pallet  10  may reduce any opportunity for insect and/or creature intrusion and may minimize any opportunity for liquids, such as spills, washing fluids, etc. to collect or pool. Thus, the encapsulated pallet  10  is increasingly insect resistant, easily washable, etc. More particularly, the deck  12  is provided with the example reinforcement rod assemblies  14 ,  20 , comprising a plurality of reinforcement rods, such as pi-shaped rods shown in  FIGS. 11A and 11B , to optionally reinforce either or both of the top and bottom of the deck  12 . For instance, the reinforcement rods  14 ,  20  may be formed from any suitable substantially rigid material, such as for example a metal, carbon fiber, etc. Finally, the top sheet  16  and the bottom sheet  20  are permanently or semi-permanently attached to the deck  12  to enclose the surfaces of the deck  12  and to seat the reinforcement rod assemblies  14 ,  20 , by any suitable process, including for instance, hot plate welding. 
     Referring to  FIGS. 4 and 5 , the example deck  12  of the pallet  10  includes a top deck surface  30  having a generally rectangular shape, a bottom deck surface  32  having a generally rectangular perimeter shape, and a plurality of spaced apart supports  34  coupled at the corners and mid-section between the top deck surface  30  and the bottom deck surface  32 , forming a gap therebetween for receiving a lifting member, such as the forks of an electric pallet jack (EPJ). By utilizing a single piece injection molded deck  12  to make the design more durable and resistant to deformations, the gap opening is, in this example, larger than the gap of similar multi-piece deck assemblies. A plurality of deck boards or stringers  36  extend between the supports  34 . In this example, the stringers  36  include chamfers  39  on the leading and trailing edges to allow easier access over the stringers  36  by the lifting member. For example, a typical EPJ includes a wheeled support fork and the chamfers  39  allow the wheels of the EPJ to be inserted and removed more easily. In one example, the chamfer is approximately 21° (see  FIG. 6B ). 
     As shown in  FIG. 5 , with a typical 40 inch span (W 40 ), the width of a formed aperture  35  is 12.2 inches, while the height of the formed aperture  35  is 3.75 inches. Similarly, with a typical 48 inch span (W 48 ), the width of a formed aperture  37  is 14.2 inches, while the height of the formed aperture is 3.75 inches. 
     As can be seen in  FIGS. 4 and 5 , each of the top deck surface  30  and the bottom deck surface  32  of the molded deck  12  includes a plurality of channels, voids, valleys, etc formed in this example by a plurality of outwardly extending ribs  31   a ,  31   b , extending generally perpendicular from the top deck surface  30  and the bottom deck surface  32 , respectively. The top reinforcement rod assembly  14  is placed within one of the channels  33   a  in the top deck surface  30 , while the bottom reinforcement rod assembly  18  is placed within one of the channels  33   b  in the bottom deck surface  32  (see  FIG. 10 ). To enclose the noted spaces and the respective reinforcement rod assemblies  14 ,  18 , the top sheet  16  is coupled to the top deck surface  30  and the bottom sheet  20  is coupled to the bottom deck surface  32 . As illustrated in  FIGS. 6A and 6B , the bottom sheet  20  is welded to the bottom deck surface  32  and as illustrated in  FIGS. 7A-7C , the top sheet  16  is welded to the top deck surface  30 , although any suitable coupling method may be utilized. Also as illustrated in  FIGS. 7A and 7B , the example top sheet  16  includes at least one grip surface  40 , such as a Thermoplastic Elastomer (TPE), which may be coextruded or otherwise coupled, attached, and/or mounted to the top sheet  16 . As will be appreciated, a similar TPE or other grip surface may be provided on the example bottom sheet  20 . The grip surface  40  thus provides a coefficient of friction that differs from that of the material from which the top sheet  16  and the bottom sheet  20  are formed and in one example, the grip surface  40  associated with the top sheet  16  may have a coefficient of friction that differs from that of the grip surface  40  associated with the bottom sheet  20 . For instance, in one example, the grip surfaces  40  would have an approximate dimension of L 47″×W 2″×H 1/16″. 
     As shown in  FIGS. 8A-9B , the deck  12  includes various features. For instance, as mentioned above, the deck  12  includes both an inner and outer chamfer. In this example, an inner chamfer  41  is manufactured with a pass through in the injection molding tooling, such as by passing through an aperture or pass-through slot  50  formed in the top deck surface  30 . In this example, there are a plurality of slots  50 , specifically four formed pass-through slots  50 . As shown in  FIGS. 9A and 9B , the deck  12  also includes a radius perimeter  52 . As illustrated, the radius perimeter allows for fluid, such as rain, to flow under the deck  12 . 
       FIG. 11A  illustrates a perspective view of an example reinforcement rod  60  that may be used with either of the reinforcement rod assemblies  14 ,  20 . As shown in  FIG. 11B , the reinforcement rods are generally “Pi-shaped” in cross section, with two flanges  61  extending from a central horizontal cross member  63 . 
     Moving to  FIGS. 22-27 , there is illustrated another example pallet  10 ′ constructed in accordance with the teachings of the present invention. In this example, the pallet  10 ′ includes a plurality of ventilation holes  210  formed through a top sheet  16 ′ and a deck  12 ′. In addition, as best seen in  FIG. 24 , the deck  12 ′ includes a plurality of outwardly extending ribs  31   a ′ that are arranged in a different reinforcement pattern than the ribs  31   a  in the pallet  10 , thereby accommodating the ventilation holes  210  (see  FIG. 4 ). The example deck  12 ′ similarly includes at least one channel  33   a ′ to accommodate various reinforcement rods, such as for example the reinforcement rod assembly  14  as previously disclosed. In a similar manner, the bottom of the deck  12 ′ includes a plurality of outwardly extending ribs  31   b ′ and at least one channel  33   b ′ to, once again, accommodate various reinforcement rids, such as for instance the reinforcement rob assembly  18 . 
     As shown in  FIGS. 26 and 27 , the deck  12 ′ likewise includes both an inner and outer chamfer. In this example, an inner chamfer  41 ′ is manufactured via a pass through in the injection molding tooling, such as by passing through an aperture or pass-through slot  50 ′ formed, once again, in a top deck surface  30 ′. In this example, there are a plurality of slots  50 ′, specifically four formed pass-through slots  50 ′. As shown in  FIGS. 9A and 9B , the deck  12  also includes a radius perimeter  52 . As illustrated, the radius perimeter allows for fluid, such as rain, to flow under the deck  12 . 
     Returning now to  FIGS. 12-21 , there is shown one example method of manufacturing the pallet  10  and the various component assemblies. While the present manufacturing methodology is disclosed with reference to the pallet  10 , it will be appreciated that the manufacturing techniques and methodologies detailed herein are applicable to any suitable pallet, including pallet  10 ′, as desired. For example,  FIG. 12  illustrates that the top sheet  16  and the bottom sheet  20  may be extruded and may include various non-slip surfaces. For example, as constructed, the top of the pallet  10  promotes resistance to slipping against a payload without components protruding from the pallet  10 , such as a grommet or molded lip. Similarly, the bottom of the pallet promotes resistance to slipping against the ground. Accordingly, as illustrated, the example top sheet  16  and bottom sheet  20  are extruded with co-extruded TPE strips to provide a non-slip surface with a low profile. 
       FIGS. 13-17B  together illustrate an example method of molding the unitary deck  12 . It will be appreciated by one of ordinary skill in the art that in general, the deck  12  is molded with a traditional molding process. However, in the present example, a few modifications to the design of the deck  12  allow for various manufacturing techniques and allow for a single form deck. For instance, as illustrated in  FIG. 14 , features  110  shown are manufactured by side action outside the perimeter of the deck  12  of the pallet  10 . The same process may be employed for the opposite side of the deck  12 . Further, as illustrated in  FIG. 15 , features  112  are similarly manufactured by side action outside of the deck  12  of the pallet  10 . Once again, the same process may be employed for the opposite side of the deck  12 . 
     Turning to  FIGS. 16A-16C , it will be appreciated that the lower chamfers, and in particular the inside chamfers  41  is manufactured with a pass through in the injection molding tooling, such as by passing through the pass-through slots  50  formed in the top deck surface  30 . In addition, a transverse region  114  is made using a sliding tool action during injection molding after the top of the mold is lifted from the deck  12  to create the inner chamfer  41  on the inner edge of the stringers  36 . In this illustrated example, the tooling slides towards the center of the deck  12  upon part ejection. 
     Turning to  FIG. 18 , once the deck  12  is unitarily formed, the top reinforcement rod assembly  14  is inserted into a reciprocal slot formed in the top of the deck  12 . Then, as shown in  FIG. 19 , the top sheet  16  is attached to the top of the deck  12 , such as by welding, to enclose the deck  12  and to prevent the top reinforcement rod assembly  14  from dislodging. 
     Once the top sheet  16  is attached, the partially assembled pallet is flipped over and the bottom reinforcement rod assembly  18  is inserted into a reciprocal slot formed in the bottom of the deck  12  as illustrated in  FIG. 20 . Then, as shown in  FIG. 21 , the bottom sheet  20  is attached to the bottom of the deck  12 , such as by welding, to enclose the bottom of the deck  12  and to prevent the bottom reinforcement rod assembly  18  from dislodging, finally resulting in the fully assembled pallet  10 . 
     It will be appreciated that in certain applications it is beneficial, if not required, for pallets to resist burning in the event of a fire and to that end, prior art pallets have been treated with fire retardant material. In the case of plastic pallets it is known to incorporate a fire retardant chemical into the plastic that is ultimately injection molded. One downside is the high cost of fire retardant chemicals, substantial quantities of which are required if included in the plastic itself. According, in one example of the present disclosure, only the top sheet  16  is treated with a fire retardant material. In another example, only the bottom sheet  20  is treated with a fire retardant material. It is further contemplated that the amount and even type of fire retardant material used with the top sheet  16  may differ from that used for the bottom sheet  20 . While it is envisioned that the fire retardant would be incorporated directly into the plastic material forming the top and bottom sheets, other means of applying or treating these components are considered within the scope of the present disclosure. Accordingly, the pallet according to the present invention may possess the required fire retardant qualities without the necessity of treating the deck  12  and thereby saving material and cost. 
     Although certain example methods and apparatus have been described herein, the scope of coverage of this patent is not limited thereto. On the contrary, this patent covers all methods, apparatus, and articles of manufacture fairly falling within the scope of the appended claims either literally or under the doctrine of equivalents.