Twin-sheet thermoformed pallet with high stiffness deck

• US 5,813,355 A
• Filed: 10/21/1996
• Issued: 09/29/1998
• Est. Priority Date: 08/15/1995
• Status: Expired due to Term

• Current Assignee: Trienda Holdings, L.L.C. (Kruger Family Industries, LLC)
• Original Assignee: TriEnda Corporation (Newell Brands Inc.)
• Inventors: Giannini, Dennis A., Brown, Henry F.
• Primary Examiner(s): Brittain, James R.
• Assistant Examiner(s): Anderson, Gerald A.
• Application Number:
  US08/729,643
• Time in Patent Office: 708 Days
• Field of Search: 108/51.1, 108/53.1, 108/53.3, 108/52.1, 108/901
• US Class Current: 108/53.3
• CPC Class Codes: B65D 19/0018 and each contact surface having a discrete foot-like shape
• CPC Class Codes: B65D 2519/00034 Plastic
• CPC Class Codes: B65D 2519/00069 Plastic
• CPC Class Codes: B65D 2519/00268 made of one piece
• CPC Class Codes: B65D 2519/00288 made of one piece
• CPC Class Codes: B65D 2519/00318 made of one piece
• CPC Class Codes: B65D 2519/00338 contact surface having a discrete foot-like shape
• CPC Class Codes: B65D 2519/0094 nestable
• CPC Class Codes: Y10S 108/901 Synthetic plastic industrial platform, e.g. pallet

Abstract

The high stiffness of the legs of a twin-sheet thermoformed pallet are effectively made to contribute to the overall stiffness of the pallet deck by utilizing vertical webs which tie into the legs through a plurality of special purpose depressions or knee Joints and which work with narrow channels in the bottom deck which extend parallel to the predominate lines of stress expected to be experienced by the pallet.

Claims

1. A twin-sheet thermoformed thermoplastic pallet, comprising;

a) a load-bearing deck formed of a first sheet of thermoplastic material defining a plane and a second sheet of thermoplastic material fused to the first sheet in selected locations; and

b) at least four feet arrayed in a rectangular array, each foot being a downwardly protruding portion of each of said first and second sheets joined together at a terminating foot floor, wherein between each foot of the array and every other of said four feet is defined a deck portion, each said deck portion being reinforced by at least one rib structure extending across said deck portion and between each of said legs, and wherein each rib is defined by at least four pockets arrayed to form the extending rib, the pockets fusing a portion of said second sheet to said first sheet at approximately the plane defined by the first sheet the pockets being elongated in a direction the ribs extend, and wherein at least two of said pockets are joined by an upstanding solid web formed in said second sheet.

2. A twin-sheet thermoformed thermoplastic pallet, comprising;

a) a means for forming a deck formed of an upper sheet of thermoplastic material defining a plane and a lower sheet of thermoplastic material;

b) at least four support means for supporting the deck means arrayed in a rectangular array, wherein between each support means and every other of said support means is a means for resisting deflection when the means for forming a deck is subjected to a deflection producing load, and wherein each means for resisting deflection includes at least four pockets arrayed to form the means, the pockets fusing a portion of said lower sheet to said upper sheet at approximately the plane defined by the upper sheet, and the pockets being elongated in a direction the means for resisting deflection extend, and wherein at least two of said pockets are joined by an upstanding solid web formed in said lower sheet, wherein the means for resisting deflection are positioned to be generally parallel to the predominant lines of stress experienced in common pallet loading conditions to thereby optimize deck stiffness between the support means.

3. A twin-sheet thermoformed thermoplastic pallet comprising:

a) an upper thermoplastic sheet, said upper sheet defining a pallet deck top surface; and

b) a lower thermoplastic sheet fused in selected locations to the upper thermoplastic sheet, wherein a plurality of upwardly opening legs are formed in the fused upper sheet and lower sheet, and a deck defined by the upper sheet and the lower sheet extends between said legs, and a plurality of downwardly opening pockets are formed in the lower sheet and fused to the upper sheet, each pocket being longer than it is wide, and fused sidewardly to at least one adjacent pocket, and wherein an upwardly opening joint depression is formed in the upper sheet adjacent to a leg, and wherein one of said pockets in said lower sheet is fused to said joint depression to define a rib extending from a leg.

4. The pallet of claim 3 further comprising a plurality of entry depressions formed in the lower sheet, and not fused to the upper sheet, along a line of entry of a lift truck tine beneath the pallet deck.

5. The pallet of claim 4 wherein the upper sheet has a downwardly extending portion which is fused to an upwardly extending portion of the lower sheet at a seam to define a peripheral deck side wall, and wherein the seam above said entry depressions is spaced a greater distance from the deck top surface than the seam not above entry depressions.

6. A twin-sheet thermoformed thermoplastic pallet, comprising;

a) a load-bearing deck formed of an upper sheet of thermoplastic material defining a plane and a lower sheet of thermoplastic material;

b) at least four feet arrayed in a rectangular array, each foot being a downwardly protruding portion of each of said upper and lower sheets joined together at a terminating foot floor; and

c) a deck portion defined between each foot of the array and every other of said four feet, wherein said deck portion is reinforced by at least one rib structured extending across said deck portion and between each of said other four feet, wherein each rib structure is defined by at least four aligned pockets, and each pocket is formed by a portion of said lower sheet fused to said upper sheet at approximately the plane defined by the upper sheet the pockets being elongated in a direction the ribs extend, and wherein at least two of said pockets are joined by an upstanding solid web formed in said lower sheet, and wherein the ribs are positioned to generally be parallel to the predominant lines of stress experienced in common pallet loading conditions to thereby optimize deck stiffness between the supporting feet.

7. The pallet of claim 6 wherein at least one of the four pockets of the at least one rib structure is fused to a foot.

8. The pallet of claim 6 wherein the rectangular array defines side deck portions between adjacent feet and wherein the side portions have continuous ribs formed by continuous adjacent pockets arrayed to form the ribs, the pockets each fusing a portion of said lower sheet to said upper sheet at approximately the plane defined by the upper sheet, said continuous adjacent pockets having an upstanding solid web therebetween and formed in said lower sheet.

9. The pallet of claim 6 wherein the rectangular array defines side deck portions between adjacent feet, and diagonal portions between opposite feet, and a central pocket approximately equidistant from all legs, and wherein the diagonal portions have ribs formed by two segments of angled ribs formed of continuous adjacent pockets arrayed to form the angled ribs between adjacent feet, the pockets each fusing a portion of said lower sheet to said upper sheet at approximately the plane defined by the upper sheet, all said continuous adjacent pockets having an upstanding solid web therebetween and formed in said lower sheet.

10. The pallet of claim 6 further comprising the tines of a lift truck which extend only partly through the pallet, with the result that a portion of the pallet is cantilevered out from the tines, and wherein rib structures extend generally parallel to the predominant lines of stress experienced when the pallet is supported on said times.

11. A twin-sheet thermoformed thermoplastic pallet comprising:

a) a deck having an upper skin and a lower skin, the upper skin being fused to the lower skin at selected locations;

b) a plurality of feet connected to the deck, wherein each foot is formed from the upper skin and lower skin and has an upwardly opening cavity;

c) a plurality of downwardly opening pockets formed in the pallet lower skin, wherein each pocket is longer than it is wide, and wherein at least a first pocket and a second pocket are formed in closely spaced relation to one another such that a web of fused plastic material is defined between the first pocket and the second pocket, and wherein said at least first pocket and second pocket define a reinforcing deck rib; and

d) a downwardly extending shell formed in the deck adjacent a foot cavity, and fused to the deck lower skin, wherein portions of said first pocket are fused to said shell, the foot being thereby joined to the rib.

12. The pallet of claim 11 having at least four feet, wherein a rib extends between each foot and at least one other foot.

13. The pallet of claim 11 wherein a plurality of ribs are positioned to generally be parallel to the predominant lines of stress experienced in common pallet loading conditions to thereby optimize deck stiffness between the plurality of feet.