Corrugated pallet

Abstract

A corrugated paperboard pallet is produced from two flat blanks which comprise a pallet top and a pallet bottom. The two blanks are each folded to produce only two parallel vertically extending double thickness ribs, three horizontal panels, two vertical side walls and two horizontal flaps. The ribs of the pallet top and pallet bottom lock each other from opening in the center of the pallet by intersecting perpendicularly with notches in the ribs. The horizontal flaps lock the ribs from opening at the edges of the pallet by intersecting perpendicularly with notches, and the vertical sidewalls include vertical flaps that open inward defining fork passages whereby the vertical flaps lock said horizontal flaps from opening.

Claims

1. A corrugated pallet produced from two flat blanks which comprise a pallet top and a pallet bottom; the blanks are each folded to produce only two parallel vertically extending double thickness ribs, three horizontal panels, two vertical side walls and two horizontal flaps; the ribs of said pallet top and the pallet bottom lock each other from opening in the center of the pallet by intersecting perpendicularly with notches; and the horizontal flaps lock the ribs from opening at the edges of the pallet by intersecting perpendicularly with notches, and the vertical sidewalls comprise vertical flaps that open inward defining fork passages whereby the vertical flaps lock the horizontal flaps from opening.

2. A corrugated pallet as defined in claim 1 wherein: the vertical flaps of the side walls provide transfer of load between the pallet bottom and the pallet top.

3. A corrugated pallet as defined in claim 2 wherein: the pallet top and the pallet bottom each have a non-crushed total flute thickness of greater than 5.6 mm and each of the pallet top and the pallet bottom has an outside width of the ribs that is greater than .sup.th the outside width of their respective sidewalls.

4. A corrugated pallet as defined in claim 3 wherein: adjacent panels of the three horizontal panels of the pallet top and the pallet bottom abut each other without overlapping and the ribs are locked free of adhesive.

5. A corrugated pallet as defined in claim 1 wherein: corners of the horizontal flaps overlap the horizontal panels and lock into outer horizontal surfaces of the pallet.

6. A corrugated pallet as defined in claim 1 wherein: the cross machine direction of the corrugation of the pallet top and the pallet bottom is perpendicular to the direction of their respective ribs.

7. A corrugated pallet as defined in claim 6 wherein: a portion of the horizontal flaps overlap portions of the horizontal panels and lock into outer horizontal surfaces of the pallet.

8. A corrugated pallet produced from two flat blanks which comprise a pallet top and a pallet bottom; the blanks are each folded to produce two parallel vertically extending double thickness ribs, three horizontal panels, two vertical side walls and two horizontal flaps, wherein: the horizontal panels of the pallet top and the pallet bottom form a top surface and a bottom surface of the pallet, respectively; and each of the vertical side walls transition at an edge of a horizontal panel to extend between the top surface and the bottom surface to define a portion of an exterior perimeter of the pallet; the ribs of the pallet top and the pallet bottom lock with each other from opening in the center of the pallet by intersecting perpendicularly with notches; and the horizontal flaps lock the ribs from opening at the edges of the pallet by intersecting perpendicularly with notches, and a portion of the horizontal flaps overlap portions of the horizontal panels and lock into outer horizontal surfaces of the pallet.

9. A corrugated pallet as defined in claim 8 wherein: the vertical sidewalls comprise vertical flaps that open inward defining fork passages whereby the vertical flaps lock the horizontal flaps from opening.

10. A corrugated pallet as defined in claim 9 wherein: the vertical flaps of the side walls provide transfer of load between the-pallet bottom and the pallet top.

11. A corrugated-pallet as defined in claim 8 wherein: adjacent panels of the three horizontal panels of the pallet top and the pallet bottom abut each other without overlapping and the ribs are locked without the use of adhesive.

12. A corrugated pallet as defined in claim 8 wherein: the cross machine direction of the corrugation of the pallet top and the pallet bottom is perpendicular to the direction of their respective ribs.

13. A corrugated pallet as defined in claim 12 wherein: the pallet top and the pallet bottom each have a non-crushed total flute thickness of greater than 5.6 mm and each of the pallet top and the pallet bottom has an outside width of the ribs that is greater than .sup.th the outside width of their respective sidewalls.

14. A corrugated pallet produced from two flat blanks which comprise a pallet top and a pallet bottom; the blanks are each folded to produce two parallel vertically extending double thickness ribs, three horizontal panels, two vertical side walls and two horizontal flaps, wherein each of the vertical sidewalls extend from an edge of a horizontal panel and the horizontal flaps extend inwards towards a center of the pallet directly from a terminal edge of the vertical side walls; the ribs of the pallet top and the pallet bottom lock with each other from opening in the center of the pallet by intersecting perpendicularly with notches; and the horizontal flaps lock the ribs from opening at the edges of the pallet by intersecting perpendicularly with notches.

15. A corrugated pallet as defined in claim 14 wherein: the cross machine direction of the corrugation of the pallet top and the pallet bottom is perpendicular to the direction of their respective ribs.

16. A corrugated pallet as defined in claim 15 wherein: the vertical sidewalls comprise vertical flaps that open inward defining fork passages whereby the vertical flaps lock the horizontal flaps from opening.

17. A corrugated pallet as defined in claim 16 wherein: the vertical flaps of the side walls provide transfer of load between the pallet bottom and the pallet top.

18. A corrugated pallet as defined in claim 14 wherein: a portion of the horizontal flaps overlaps portions of the horizontal panels and lock into outer horizontal surfaces of the pallet.

19. A corrugated pallet as defined in claim 18 wherein: the corners of the horizontal flaps overlap portions of the horizontal panels and lock into outer horizontal surfaces of the pallet.

20. A corrugated pallet as defined in claim 14 wherein: adjacent panels of the three horizontal panels of the pallet top and the pallet bottom abut each other without overlapping and the ribs are locked without the use of adhesive.

21. A foldable pallet comprising: a top member consisting of two top ribs, three top horizontal panels, two top vertical sidewalls, and two top horizontal flaps; and a bottom member consisting of two bottom ribs, three bottom horizontal panels, two bottom vertical sidewalls, and two bottom horizontal flaps; wherein the top horizontal flaps lock the bottom ribs from opening at the edges of the pallet by intersecting perpendicularly with notches, and the bottom horizontal flaps lock the top ribs from opening at the edges of the pallet by intersecting perpendicularly with notches.

22. The foldable pallet of claim 21 wherein the top vertical sidewalls comprise top vertical flaps that open inward defining fork passages whereby the top vertical flaps lock the bottom horizontal flaps from opening; and the bottom vertical sidewalls comprise bottom vertical flaps that open inward defining fork passages whereby the bottom vertical flaps lock the top horizontal flaps from opening.

Description

DESCRIPTION OF THE DRAWINGS

(1) The invention and its many advantages and features will become better understood upon reading the following detailed description of the preferred embodiments in conjunction with the following drawings, wherein:

(2) FIG. 1 is a schematic drawing of a corrugated paperboard pallet in accordance with the invention.

(3) FIG. 2 is a schematic drawing of the pallet of FIG. 1 in partially folded but unassembled state, in accordance with the invention.

(4) FIG. 3 is a schematic drawing of the pallet of FIG. 1 prior to assembly in flat blanks state in accordance with the invention.

(5) FIG. 4 is a schematic drawing of the pallet bottom of the pallet of FIG. 1 in the assembly process with ribs folded up in accordance with the invention.

(6) FIG. 5 is a schematic drawing of the pallet top of the pallet of FIG. 1 in the assembly process with ribs folded down in accordance with the invention.

(7) FIG. 6 is a schematic drawing of the pallet bottom and pallet top of the pallet of FIG. 1 in the assembly process aligned prior to compression together in accordance with the invention.

(8) FIG. 6A is a cut-away perspective view of one end of the pallet of FIG. 1, showing how the horizontal flap is tucked under the top sheet, with slots engaging the ribs to hold them closed and to hold the top and bottom panels together.

(9) FIG. 7 is a schematic drawing of the pallet bottom and pallet top of the pallet of FIG. 1 in the assembly process after being compressed together in accordance with the invention.

(10) FIG. 7A is a cut-away perspective view of the pallet of FIG. 1, showing the inter-engagement of the intersecting ribs in the central area of the pallet.

(11) FIG. 8 is a schematic drawing of the pallet of FIG. 1 in the assembly process after the horizontal flaps have been inserted in accordance with the invention.

(12) FIG. 9 is a schematic drawing of the pallet of FIG. 1 in the assembly process after the fork passages are folded open in accordance with the invention.

(13) FIG. 10 is a schematic drawing of the pallet of FIG. 1 in the assembly process after the top and bottom locking straps are folded over in accordance with the invention.

(14) FIG. 11 is a schematic drawing of the pallet bottom of the pallet of FIG. 1 marked showing the corrugation directions with respect to rib direction, in accordance with the invention.

(15) FIG. 12 is a comparison of the corrugated paperboard use per pallet between the prior art and the invention.

(16) FIG. 13 is a comparison of the pallet shipping per truckload between the prior art and the invention.

(17) FIG. 14 is a comparison of the relative pallet torsional stiffness between the prior art and the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

(18) Turning to the drawings, wherein like reference characters designate identical or corresponding parts, FIG. 1 shows a corrugated paperboard pallet 30 in accordance with the invention. The pallet 30 has fork passages 31, 32 for lifting and moving the pallet when loaded with shipping goods. The pallet 30 is compromised of a pallet bottom 50 and a pallet top 70 that are comprised of sheets of corrugated paperboard.

(19) A schematic drawing of the pallet of FIG. 1 in partially folded but unassembled state, in accordance with the invention is shown in FIG. 2. The corrugated paperboard pallet 30 is produced from two flat blanks which comprise a pallet top 70 and a pallet bottom 50. The blanks 70, 50 are each folded to produce only two parallel vertically extending double thickness discontinuous ribs 71 and 51, three horizontal panels 40 and 45, two vertical side walls 41, 42, 46, 47 and two horizontal flaps 43, 44, 48, 49. The ribs 71 of the pallet top 70 and the ribs 51 of the pallet bottom each have a central portion and two rib ends. The central portions of the ribs 51 and 71 lock each other from opening in the center of the pallet 30 by intersecting perpendicularly with notches 53, as shown in FIG. 7A. As shown in FIG. 6A, when completely assembled, the horizontal flaps 43, 44, 48, 49 lock the end portions of the ribs 71, 51 from opening at the edges of the pallet 30 by intersecting perpendicularly with notches 57, 58, 75, 55, 77. The vertical sidewalls 41, 42, 46, 47, once assembled, have vertical flaps 59, 79 that open inward defining fork passages whereby the vertical flaps lock horizontal flaps 43, 44, 48, 49 from opening.

(20) A schematic drawing of the pallet of FIG. 1 prior to assembly in flat blanks state in accordance with the invention is shown in FIG. 3. The pallet 30 is produced from two flat, die cut corrugated paperboard blanks that produce the pallet top 70 and pallet bottom 50. To facilitate shipping, it is preferable that the blanks 50, 70 be shipped flat to the shipper site such that more blanks can fill a truckload.

(21) The pallet bottom of the pallet of FIG. 1 is shown in the assembly process with ribs folded up in FIG. 4. The pallet bottom 50 is folded to produce only two vertically extending double thickness discontinuous ribs 51 near the longitudinal center, three horizontal panels 45, two sidewalls 46, 47 that will be vertical in the assembled pallet and two horizontal flaps 48, 49.

(22) The pallet top of the pallet of FIG. 1 is shown in the assembly process in FIG. 5 with ribs 71 folded down. The pallet top 70 is folded to produce only two vertically extending double thickness discontinuous ribs 71 near the longitudinal center, three horizontal panels 40, two sidewalls 41, 42 that will be vertical in the assembled pallet and two horizontal flaps 43, 44.

(23) A schematic drawing of the pallet bottom and pallet top of the pallet of FIG. 1 in the assembly process aligned prior to compression together in accordance with the invention is shown in FIG. 6. The pallet 30 is assembled by rotating the pallet top 70 and pallet bottom to be perpendicular with each other and aligned such that ribs 71, 51 cross and nest in notches 53, as illustrated in FIG. 7A. The pallet bottom 50 has openings 54 for pallet jack wheels, should a pallet jack be used to lift and move the finished pallet 30. The ribs 51, 71 are preferably locked without the use of adhesive. The ribs 51, 71 may be mechanically locked during the intermediate step before assembly of the pallet top 70 with pallet bottom, through the use of rib punch locks 52. However, for simplicity and strength, preferably no rib punch locks are utilized and ribs 51, 71 are locked closed by each other in the center when assembled together using notches 53. The end portions of the ribs 51, 71 are later locked by notches 57, 58 with 75, 76 and with 77, 78 with 56, 56.

(24) One end of the pallet of FIG. 1, shown in FIG. 6A, illustrates how the horizontal flap 48 of the pallet bottom 50 is tucked under the pallet top 70, with notches 57 engaging the top of the ribs 71 to hold them closed and to lock the top and bottom panels against separating. We have found it to be desirable that the pallet be designed so that it maintains integrity throughout shipping and handling vibration and loading conditions. We have found that one way to accomplish this goal is to design the pallet using multiple series locks. For example, the top blank ribs 71 are locked from opening by the bottom blank ribs 51. The top blank horizontal flaps 43, 44 lock the bottom blank ribs 51 from opening. The top blank vertical flaps 79 lock the top blank horizontal flaps 43, 44 from opening. The corner straps 91, 92 clamp the pallet top and bottom together, thereby locking the top blank vertical 79 flaps from opening.

(25) Once aligned, the pallet top 70 and pallet bottom 50 are compressed together. A schematic drawing of the pallet bottom and pallet top of the pallet of FIG. 1 in the assembly process after being compressed together in accordance with the invention is shown in FIG. 7. The pallet 30, in compressed stated, is shown in FIG. 7. Horizontal flaps 48, 49, are ready to be folded to engage the notches 57, 58 with the notches 75 on the rib ends of the ribs 71 to lock the edges of ribs 71 closed, and the horizontal flaps 43, 44 are ready to be folded to engage the notches 77, 78 with the notches 55, 56 on the rib ends of the ribs 51 to lock the edges of ribs 51 closed.

(26) A schematic drawing of the pallet of FIG. 1 in the assembly process after the horizontal flaps have been inserted in accordance with the invention is shown in FIG. 8. The pallet 30 has the pallet top 70 and pallet bottom 50 locked together by the sidewalls 41 and 46 being folded vertical and horizontal flaps 43, 48 locking the edges of the end portions of the ribs 71, 51. The corner straps 91, 92 of the horizontal flaps 43, 48 are not assembled yet and will later be locked to the pallet top 70 and pallet bottom 50 through slots 93. Vertical flaps 59, 79 on the sidewalls 41, 46 are ready to be assembled.

(27) A schematic drawing of the pallet of FIG. 1 in the assembly process after the fork passages are folded open in accordance with the invention is shown in FIG. 9. The pallet 30 has pallet top 70 locked together with pallet bottom 50. The sidewalls 42, 46 are vertical as the horizontal flaps 43, 48 are locking the edges of the ribs 51, 71. Vertical flaps 59, 79 are folded inward defining fork passages 31, 32. The vertical flaps 59, 79 also thereby lock the horizontal flaps 43, 49 from opening.

(28) The final assembly step is locking the corners of the pallet 30. A schematic drawing of the pallet of FIG. 1 in the assembly process after the top and bottom locking straps are folded over in accordance with the invention is shown in FIG. 10. The pallet 30 is completed with pallet top assembled together with pallet bottom. The corners 91, 92 of the horizontal flaps 42, 46 overlap the pallet top 70 and pallet bottom 50 and lock into the pallet top and the pallet bottom from the top and bottom surfaces of the pallet 30. The corner straps 91, 92 lock into slots 93, 94.

(29) Corrugated paperboard is constructed with two directions; machine direction which is the direction it is pulled during fabrication and cross machine direction which is perpendicular to it, and is the axial direction of the flutes inside the corrugated paperboard. A schematic drawing of the pallet bottom of the pallet of FIG. 1 marked showing the corrugation material directions with respect to rib direction, in accordance with the invention is shown in FIG. 11. In order to provide maximum load capacity for the pallet 30 and transfer of load between the pallet top and pallet bottom 50, the cross machine direction 102 is preferably perpendicular to the rib direction 100.

(30) Although many corrugated pallets are designed using a high amount of corrugated paperboard, the invention even provides substantial savings compared to lighter two piece type corrugated pallets. A comparison of the corrugated paperboard use per pallet between the prior art two piece pallet and the invention is shown in FIG. 12. The corrugated paperboard use per pallet is shown with a prior art four-rib per blank pallet 121 using 56 sq-ft compared to a 20% reduction for the invention 122 at 45 sq-ft. This directly translates to a 20% reduction in raw material costs.

(31) One of the most significant benefits of the invention is that the blanks can be shipped flat and be easily assembled on site at a shipper, compared to prior art corrugated pallets that must be preassembled at an outside plant due to complexity. This greatly increases the number of pallets that can be shipped per truckload. The blanks may also be shipped directly from a corrugator or sheet plant to a product shipper without secondary transportation and logistics. A bar chart shown in FIG. 13 shows a comparison of the pallet shipping per truckload between the prior art and the invention. The pallet shipping per truckload for prior art preassembled pallets 131 is roughly 600 pallets. The pallet shipping per truckload with the invention 132 is 2160. This ability directly translates to lower shipping and handling costs from both more pallets per truckload and from preferably only shipping blanks directly to the product shipper.

(32) Besides the cost savings, the invention also provides a stronger and stiffer pallet with increased reliability. A bar chart shown in FIG. 14 shows a comparison of the relative pallet torsional stiffness between the prior art and the invention. The relative pallet torsional stiffness is increased by about 85% in the invention 142 in comparison with a prior art two piece pallet without corner straps 141. During vibration as well as lifting of highly unbalanced loads, the invention is much more likely to perform without failure or separation of the pallet top and pallet bottom.

(33) Obviously, numerous modifications and variations of the described preferred embodiment are possible and will occur to those skilled in the art in light of this disclosure of the invention. Accordingly, I intend that these modifications and variations, and the equivalents thereof, be included within the spirit and scope of the invention as defined in the following claims,