Patent Publication Number: US-10322847-B2

Title: Pallet with support elements configured as one-piece skids and related methods

Description:
RELATED APPLICATIONS 
     This application is a divisional of U.S. patent application Ser. No. 14/127,309 filed on Apr. 21, 2014 which is a 371 of PCT/EP2012/063731 filed on Jul. 12, 2012 which claims the priority to European Patent Application No. 11174175.7 filed on Jul. 15, 2011, which are hereby incorporated herein in their entirety by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to the field of pallets, and more particularly, to a pallet having an improved resilience to impacts from material handling equipment while still supporting a nominal load capacity, and to related methods for making the same. 
     BACKGROUND OF THE INVENTION 
     Conventional wood pallets include a base layer and a cargo layer separated therefrom by support blocks. The cargo layer has end deck boards assembled on connector boards that run the full length or width of the pallet. The end deck boards are coupled through the connector boards to the support blocks to build the primary structure of the pallet. The end deck boards are also known as lead boards, and the connector boards are also known as stringer boards. The base layer has end deck boards coupled to the support blocks. 
     To move the wooden pallets with cargo thereon, the lifting members of material handling equipment, such as fork lift tines from a forklift, are inserted into the gaps between the base and cargo layers. If the forklift is not stopped in time, the forklift crashes into one of the end deck boards of the pallet. Impacts such as this weaken the pallet and greatly shorten the lifespan of the pallet, thereby causing the pallet to be repaired more frequently and/or removed from service before its anticipated life cycle has been reached. 
     One approach for improving the resilience to impacts from material handling equipment is disclosed in FR 26600283, which provides separate support elements made out of plastic that have notches formed therein to receive connector boards from the cargo layer. The connector boards are positioned edgewise. 
     Another approach is disclosed in GB 2080763 which provides a support element configured as an elongated block of low density cellular material, such as polystyrene. An upper surface of the support element includes a sheet of stiffening material, and a corresponding lower surface also includes a sheet of stiffening material. The sheets of stiffening material may be wood, for example. An adhesive or other bonding material may be used to secure the sheets of stiffening material to the support element. 
     Yet another approach is disclosed in GB 2265137 which provides a plastic pallet comprising three spaced apart support elements that are linked together by three base plank members. The base plank members are orthogonal to the support elements. Supported by the support elements is a plurality of beams. Each of the support elements is an elongated member having on its upper surface a series of upstanding ribs and on its lower surface three recesses integrally connected together by sections. The beams are positioned between the ribs and bridge the three support elements while the base plank members located in the recesses bridge the support elements. Each support element comprises a one-piece member composed of a plastic material. Each beam is a hollow extruded member. The base plank members are also hollow extruded members. 
     Even in view of the above-described pallets, there is still a need to lengthen the lifespan of a pallet by improving its resiliency to impacts from material handling equipment. 
     SUMMARY OF THE INVENTION 
     In view of the foregoing background, it is therefore an object of the present invention to provide a pallet that has improved resiliency to impacts from material handling equipment while maintaining support of nominal load capacities. 
     This and other objects, advantages and features in accordance with the present invention are provided by a pallet comprising a base layer and a cargo layer, with the cargo layer comprising a pair of spaced apart connector boards and a pair of spaced apart end deck boards orthogonal to said pair of connector boards. The pallet may further comprise a plurality of spaced apart support elements positioned between the base layer and the cargo layer and forming a gap therebetween for receiving a lifting member, with each support element extending in length between the pair of spaced apart end deck boards and configured as a one-piece skid, and including an open recessed channel therein to receive a respective connector board from the cargo layer. 
     Each support element may comprise a connector board receiving area, and a plurality of spaced apart support blocks integrally formed with the connector board receiving area and contacting the base layer. The connector board receiving area may include the open recessed channel that is to receive the respective connector board. The connector board receiving area may also comprise spaced apart sidewalls adjacent sidewalls of the respective connector board received therein, and open ends exposing ends of the respective connector board. 
     With the support element configured as one-piece skids and extending the full depth of the pallet, the resiliency to impacts from material handling equipment is improved. This is particularly so with when the support element is molded from plastic. To provide the necessary stiffness so that a support element can support a support of nominal load capacity, the connector board from the cargo is positioned within the open recessed area. Each connector board and each deck board may comprise wood. 
     The open recessed channel in each support element may have a depth equal to a thickness of the connector board placed therein so that an outer exposed surface of the connector board is coplanar with an outer exposed surface of the support element. 
     Each support element may further comprise a pair of backstops positioned immediately adjacent a respective end deck board. This further increases the resiliency of the pallet to impacts from material handling equipment, as well as improving the structural rigidity. When an impact force is applied to an end deck board, the backstops advantageously absorb the impact force instead of the fasteners used to secure the end deck boards to the support elements. The backstops may be integrally molded with each support element. 
     The cargo layer may further comprise a plurality of intermediate deck boards between the pair of end deck boards. The cargo layer may further comprise at least one intermediate connector board. The pallet may further comprise at least one intermediate support element positioned between the base layer and the cargo layer and extending in length between the pair of spaced apart end deck boards and configured as a one-piece skid, and including an open recessed channel therein to receive the at least one intermediate connector board. 
     The base layer may comprise a pair of spaced apart bottom end deck boards extending across the plurality of spaced apart support elements in a same direction as the end deck boards in the cargo layer, and at least one intermediate bottom deck board between the pair of bottom end deck boards. 
     Yet another aspect is directed to a method for making a pallet as described above. The method may comprise providing the plurality of spaced apart support elements, with each support element extending in length between the pair of spaced apart end deck boards and configured as a one-piece skid, and including an open recessed channel therein. A respective connector board of the cargo layer may be positioned in each open recessed channel of the plurality of spaced apart support elements. The method may further comprise fastening the pair of spaced apart end deck boards of the cargo layer to a top side of the plurality of spaced apart support elements, and fastening the pair of spaced apart bottom end deck boards of the base layer to a bottom side of the plurality of spaced apart support elements. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a pallet in accordance with the present invention. 
         FIG. 2  is a perspective view of the pallet shown in  FIG. 1  without the end deck boards and intermediate deck boards from the cargo layer. 
         FIG. 3  is a perspective view of a support element with an open recessed channel, and a respective connector board from the cargo layer to be positioned in the open recessed channel in accordance with the present invention. 
         FIG. 4  is a side view of an end of the support element shown in  FIG. 3  with the connector board positioned in the open recessed channel. 
         FIG. 5  is a perspective view of a support element with a connector board, with backstops extending across the connector board, and with rivets used to secure the end deck boards and intermediate deck boards to the support element in accordance with the present invention. 
         FIG. 6  is a perspective view of another embodiment of the support element shown in  FIG. 5  wherein the backstops do not extend across the connector board. 
         FIG. 7  is a flowchart illustrating a method for making a pallet in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, 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 be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout, and prime notation is used to indicate alternative embodiments. 
     Referring initially to  FIGS. 1 and 2 , a pallet  10  comprises a base layer  20 , a cargo layer  30 , and spaced apart support elements  40  positioned between the base and cargo layers to define a space  50  therebetween for receiving the lifting members of material handling equipment, such as fork lift tines from a forklift. The cargo layer  30  comprises a pair of spaced apart connector boards  32 , and a pair of spaced apart end deck boards  34  orthogonal to the connector boards. The end deck boards  34  are also known as lead boards, and the connector boards  32  are also known as stringer bards. 
     The illustrated pallet  10  is substantially rectangular shaped. An example size of the pallet  10  is 800 mm deep by 1200 mm wide, with a height of 144 mm. As readily appreciated by those skilled in the art, the pallet  10  is not limited to these dimensions, and may be formed with other dimensions. Moreover, the pallet  10  may be formed having a substantially square shape. 
     In particular, each support element  40  extends in length between the pair of spaced apart end deck boards  34  and is configured as a one-piece skid. Each support element  40  includes an open recessed channel therein to receive a respective connector board  32  from the cargo layer. 
     With the support element  40  configured as one-piece skids and extending the full depth of the pallet  10 , the resiliency to impacts from material handling equipment is improved. This is particularly so with when the support element  40  is molded from plastic. To provide the necessary stiffness so that a support element  40  can support a nominal load capacity, the connector board  32  from the cargo layer  30  is positioned within the open recessed area  60 . 
     The illustrated pallet  10  also includes at least one intermediate support element  42 , and the cargo layer  30  includes at least one intermediate connector board  36 , and a plurality of intermediate deck boards  38  between the end deck boards  34 . The connector boards  32  are similar in design and function as the intermediate connector board  36 . 
     A perspective view of the pallet  10  without the end deck boards  34  and the intermediate deck boards  38  from the cargo layer  30  is provided in  FIG. 2 . The base layer  20  includes a pair of spaced apart bottom end deck boards  24  extending across the spaced apart support elements  40 , and the intermediate support element  42  positioned therebetween. The bottom end deck boards  24  extend in a same direction as the end deck boards  34  in the cargo layer. The base layer  20  also includes an intermediate bottom deck board  28  between the pair of bottom end deck boards  24 . 
     Normally, pallets include a separated support block positioned between the base and cargo layers to define a space therebetween for receiving the lifting members of material handling equipment. In sharp contrast, with each support element  40  in the illustrated pallet  10  being configured as a one-piece skid, this advantageously combines multiple support blocks into a single component. In this example, three support blocks are being combined into a one-piece skid. 
     Each support element  40  may be molded from thermoplastic or other polymer materials, including high density polyethylene (HDPE), polypropylene (PP), among other polymer materials. As may be appreciated by those skilled in the art, the polymer materials may be filled or unfilled and/or may include particulate or fibrous, natural or synthetic materials, among other features. For example, unfilled HDPE may provide improved impact strength, PP having strengtheners (e.g., long or short glass fibers, impact modifiers or performance enhancement additives) may provide improved structural properties, and unfilled PP with random copolymers may provide improved reinforcement qualities. 
     In order for each support element  40  to provide the necessary stiffness to maintain a desired rate load, such as 1000 kg, for example, a connector board  32  from the cargo layer is placed within an open recessed channel  60 , as best illustrated in  FIGS. 3 and 4 . Although the intermediate support element  42  is not discussed in detail, discussion of the support elements  40  is applicable to the intermediate support element, as readily appreciated by those skilled in the art. 
     Each support element  40  comprises a connector board receiving area  62 , and a plurality of spaced apart support blocks  64  integrally formed with the connector board receiving area. The connector board receiving area  62  includes the open recessed channel  60  that is to receive the respective connector board  32 . The connector board receiving area  62  also includes spaced apart sidewalls  66  adjacent sidewalls of the respective connector board  32  received therein, and open ends exposing ends of the respective connector board. 
     The open recessed channel  60  in each support element  40  has a depth equal to a thickness of the connector board  32  placed therein so that an outer exposed surface of the connector board is coplanar with an outer exposed surface of the sidewalls  66  of the support element, as best illustrated in  FIG. 4 . 
     Manufacturing and assembly of the pallet  10  is advantageously simplified with the use of support elements  40  being configured as one-piece skids that also have an open recessed channel  60  for receiving a connector board from the cargo layer  30 . As readily appreciated by those skilled in the art, discussion of the support elements  40  is applicable to the intermediate support element  42 . The intermediate support element  42  is thus similar in design and function as the other support elements  40 . 
     Since the support elements  40  and the intermediate support element  42  are both formed out of plastic, they have a high impact resistance during impact with the tines of a forklift. In addition, the support element  40  and the intermediate support element  42  may include rounded corners/edges  68  along the perimeter thereof, which also helps to reduce and/or deflect damage during impact with the tines of a forklift, as well as providing an improved aesthetic appearance. 
     To further improve impact resistance and structural rigidity, each support element  40  and the intermediate support element  42  may optionally include a pair of backstops  70  that extend across the width of the connector board  32  or across the width of the intermediate connector board  36 , as best shown in  FIGS. 2 and 5 . Each backstop  70  extends across a width of the open recessed channel and is positioned immediately adjacent a respective end deck board  34 . When an impact force is applied to an end deck board  34 , the backstops  70  absorb the impact force instead of the fasteners used to secure the end deck boards  34  to the support elements  40 . 
     In an alternative embodiment, the backstops  70 ′ do not extend across the width of the connector board  32 ′ or across the width of the intermediate connector board, as best shown in  FIG. 6 . Instead, the backstops  70 ′ are limited to the sidewalls of the support element  40 ′ and the intermediate support element. 
     Each backstop  70 ,  70 ′ embodiment may be integrally formed with the support element  40 ,  40 ′ and with the intermediate support element  42 . In this case, each backstop  70 ,  70 ′ is molded from the same thermoplastic or other polymer materials used for the support elements  40 ,  40 ′ and the intermediate support element  42 . 
     Alternatively, each backstop  70 ,  70 ′ may be separately formed from the support element  40 ,  40 ′ and from the intermediate support element  42 . In this case, the backstops  70 ,  70 ′ may be molded from different thermoplastics or polymer materials. For example, the backstops  70 ,  70 ′ may be molded from a first type of thermoplastic or polymer material, while the support elements  40 ,  40 ′ and the intermediate support element  42  may be molded from a second type of thermoplastic or polymer material. 
     Fasteners  80  are used to couple the end deck boards  34  to the support elements  40 . The fasteners  80  may be rivets, for example. The fasteners  80  may extend all the way through the pallet from the top to the bottom, i.e., from the cargo layer  30  to the base layer  20 . Alternatively, the fasteners  80  may extend all the way through the pallet from the bottom to the top, i.e., from the base layer  20  to the cargo layer  30 . In addition, some of the fasteners  80  extend from the top to the bottom while some of the fasteners extend from the bottom to the top within the same pallet  10 . 
     The connector boards  32  and end deck boards  34  are pre-drilled with “rivet” holes extending therethrough. Similarly, the support elements  40  are pre-dilled with “rivet” holes for receiving the rivets  80 . The rivets  80  allow the end deck boards  34  and the intermediate deck boards  38  to be secured to a top side of the support elements  40  and to the intermediate support elements  42 . The intermediate deck boards  38  that are not directly over a support block  64  are coupled to the support element  40  or the intermediate support element  42  using fasteners other than rivets, such as nails or staples, for example. 
     Rivets  80  are used to secure the bottom end deck boards  24  and the intermediate bottom deck board  28  of the base layer  20  to a bottom side of the support elements  40  and the intermediate support element  42 . Other types of fasteners may be used, as readily appreciated by those skilled in the art, such as nails and staples, for example. 
     Another aspect is directed to a method for making a pallet  10  as described above. Referring now to the flowchart  100  illustrated in  FIG. 7 , from the start (Block  102 ), the method comprises providing the plurality of spaced apart support elements  40  at Block  104 , with each support element  40  extending in length between the pair of spaced apart end deck boards  34  and configured as a one-piece skid, and including an open recessed channel  60  therein. A respective connector board  32  of the cargo layer  30  is positioned at Block  106  in each open recessed channel  60  of the spaced apart support elements  40 . 
     The method further comprises fastening the pair of spaced apart end deck boards  34  of the cargo layer  30  to a top side of the spaced apart support elements  40  at Block  108 , and fastening the pair of spaced apart bottom end deck boards  24  of the base layer  20  to a bottom side of the spaced apart support elements  40  at Block  110 . The method ends at Block  112 . 
     Many modifications and other embodiments of the invention will come to the mind of one skilled in the art having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is understood that the invention is not to be limited to the specific embodiments disclosed, and that modifications and embodiments are intended to be included as readily appreciated by those skilled in the art.