Pallet Structure

Abstract

A pallet structure comprises a grid or network formed of a plurality of spaced ribs substantially narrower in width than in depth and having upper edges substantially coplanar and defining a load supporting platform. The ribs are preferably of substantially equal lateral spacing across the pallet structure but may vary with the spacing being such that the ribs will properly support the goods to be deposited thereon. The structure has a plurality of spaced vertical hollow legs or supports depending from the load supporting platform and a marginal edge portion extending around the periphery of the grid structure with the edge portion having a bottom wall member extending between an edge rib and an adjacent parallel rib thereby defining an edge support surface. The pallets are stackable when empty due to the supports nesting one in another and are such that the edges are spaced whereby a lift fork is insertible therebetween to separate and lift a desired portion of a stack. The edge of the pallet is shaped to provide a convenient portion for manually moving individual pallets.

Description

The present invention relates to a load-bearing pallet and more particularly to a plastic pallet having an open grid structure which is nestable, adapted to permit a desired number to be easily separated from a stack of a plurality of like pallets, and has an edge thined for convenient handling.

The principal objects of the present invention are: to provide a light weight plastic pallet having an open grid deck or platform structure and having legs which are nestable and having edge portions adapted to permit a desired number of pallets to be easily separated from a stack of a plurality of like pallets; to provide such a pallet which is easily handled and moved on conveying equipment and which has an edge portion shaped and sized to form a space between adjacent pallets of a stack and to guide arms of a fork lift to effect easy separation of a desired number of pallets from a stack; to provide such a pallet structure which is adapted for service over a wide temperature range, such as substantially below 0.degree. F. and substantially above 200.degree. F.; to provide a reusable load-bearing pallet capable of supporting heavy loads during storage and transportation; to provide such a pallet which is generally rectangular and adapted to be lifted using mechanical pallet handling equipment from any of its sides; to provide such a pallet adapted for easy passage of banding or other tying material through the pallet from any of its sides or through an open grid deck structure during securing the load to the pallet; to provide a strong, light weight, inexpensive and durable pallet; to provide such a pallet which is formed of structural foam plastic having a substantially increased useful life, as compared to wood and paper pallets; to provide such a plastic pallet adapted to be nested or stacked vertically in a minimum of space to minimize shipping costs; to provide such a plastic pallet having an open grid deck structure thereby permitting easy banding of irregular sized and shaped loads; to provide such a plastic pallet having a marginal edge portion around the periphery thereof which is adapted to permit wheels on a conveyor to movably support the pallet for movement along the conveyor; and to provide such a pallet which is economical to manufacture, durable in construction, weather resistant, immune to rot and growth of fungus or other micro-organisms, rigid, dimensionally stable in a humid atmosphere and over a wide temperature range, and particularly well adapted for the proposed use.

Other objects and advantages of this invention will become apparent from the following description taken in connection with the accompanying drawings wherein are set forth by way of illustration and example certain embodiments of this invention.

FIG. 1 is a plan view of a pallet embodying features of the present invention.

FIG. 2 is a side elevational view of the pallet.

FIG. 3 is a longitudinal, sectional view through the pallet taken on line 3--3, FIG. 1.

FIG. 4 is an enlarged fragmentary sectional view of a marginal edge portion of the pallet.

FIG. 5 is a side elevational view of a plurality of like pallets stacked vertically showing the space between adjacent marginal edge portions.

FIG. 6 is a fragmentary sectional view of a modified rib showing reinforcing members therein.

Referring more in detail to the drawings:

The reference number 1 generally designates a load-bearing pallet which is a one piece, integral structure formed of a suitable plastic. It is preferable that the pallet 1 be formed by molding, particularly of a light weight material, such as a structural formed plastic, for example, polycarbonate, polyethylene, urethane, polypropylene, or the like to thereby form a light weight rigid pallet structure. It is desirable that the pallet 1 be formed of polypropylene when the pallet 1 is to be subjected to temperatures in the nature of 250.degree. F.

It is preferable that the pallet 1 have a density in the range of 25 lbs. per cubic foot to 44 lbs. per cubic foot. These values represent 40 to 70 percent densities when compared to the density of water, namely 62.5 lbs. per cubic foot.

The pallet has a load supporting platform 2 and a plurality of nestable leg members or supports 3 depending from the load supporting platform 2. The pallet 1 is particularly adapted for storing and transporting material or merchandise and the legs or supports 3 are arranged to provide easy access from any direction for the arms or prongs of a fork lift (not shown) between adjacent legs 3 and for easy insertion of banding or other tying material used to secure a load thereto.

The load supporting platform 2 is formed of a plurality of spaced intersecting perpendicular ribs 4 and 5 respectively. The ribs 4 and 5 have the upper edges 6 thereof in registry in a common plane thereby defining the load supporting platform 2. The ribs 4 and 5 are each deep members which are substantially narrower in width than depth and are narrower at their lower edges than at their upper edges to permit removal from a mold (not shown).

It is desirable to provide the load supporting platform 2 with a large surface area in contact with the load on the pallet to thereby distribute the load over a wide area and decrease the unit load, therefore, the ribs 4 and 5 each have lateral extensions from each side at the upper edge thereof with the upper surfaces of the extensions being in the common plane with the upper edges 6 of the ribs 4 and 5.

The pallet 1 is nestable with like pallets and it is desirable that the load supporting surface 2 be fully supported when stacked, therefore, the ribs 4 and 5 each have lower edges 7 thereof in a common plane spaced from and substantially parallel with the plane of the upper edges 6 of said ribs. When the pallets are nested or stacked vertically, the lower edges 7 of the ribs of an upper pallet engage and are supported on the upper edges 6 of ribs of a lower pallet.

A marginal edge portion 8 extends continuously around the periphery of the grid structure formed by the ribs 4 and 5 and the marginal edge portion 8 has an edge rib 9 parallel with and laterally spaced from an adjacent rib 9' of the grid structure. A bottom wall member 10 extends between the edge rib 9 and the adjacent parallel rib 9' thereby defining an edge support surface which is particularly adapted to be movably supported on rollers of a conveyor (not shown) whereby the pallet 1 and a load thereon may be moved along the conveyor.

It is desirable to provide a space between the marginal edge portions 8 of adjacent pallets when same are stacked vertically to permit easy entrance for the arms or prongs of a fork lift between pallets to be separated, therefore, the edge rib 9 has less depth than the ribs 4 and 5. The adjacent parallel rib 9' has a depth intermediate that of the edge ribs 9 and the ribs 4 and 5.

A lower surface of the bottom wall member 10 is positioned intermediate the planes of the upper and lower edges 6 and 7 of the ribs 4 and 5 and each of the ribs 4 and 5 have opposite end portions 11 sloped between a lower edge of the adjacent parallel rib 9' and the lower edge 7 of the respective rib, thereby forming a ramp surface to be engaged by the prongs or arms of a conventional fork lift (not shown) to thereby facilitate separation of adjacent pallets when stacked or nested. Engagement of the arms or prongs of the fork lift with the end portions 11 of the ribs 4 and 5 raises the upper pallet out of the lower pallet to facilitate easy separation of upper pallet and pallets thereabove from a stack of like pallets.

The legs or supports 3 are laterally spaced, vertical members so spaced apart to permit easy ingress of lifting members, such as the arms or prongs of a convention fork lift, therebetween and to permit ingress of banding or tying material and the arms or prongs of the fork lift from any side of the pallet 1.

The nestable leg members 3 each have an open upper end or top 12 and each of the leg members 3 are downwardly and inwardly sloped from the load supporting surface 2 whereby like pallet structures are stackable vertically. The leg members may be any desired shape, however, in the illustrated structure, the nestable leg members 3 are each rectangular and have side walls 13 each having the upper edges thereof aligned with the upper edge 6 of the respective ribs of the grid structure forming the load supporting platform 2. The side walls 13 of the nestable leg members 3 each have at least one rib of the grid structure normal thereto and positioned intermediate the ends of the respective side wall. When the nestable leg members 3 are in side-by-side position, the side walls 13 have a common upper portion 14, as best seen in FIG. 3.

The leg members 3 each have a bottom wall member 15 closing a lower end thereof to thereby provide additional area over which to distribute the supported load.

Particularly when the pallet 1 is stored in an area which is unprotected from the elements, it is desirable to provide means to prevent the collection of liquid within the open top leg members 3, therefore, each of the bottom wall members 15 has an aperture 16 extending vertically therethrough. It is also desirable to provide a plurality of apertures 17 through the bottom wall member 10 of the marginal edge portion 8. An aperture 17 is formed for each compartment formed by extensions of the end portions 11 of the ribs which extend normal to the edge rib 9 and the adjacent parallel rib 9' thereby preventing collection of liquid in the compartments by permitting liquid to flow through the apertures 17 and away from the pallet 1.

The pallet 1 is designed to permit the lower edges 7 of an upper pallet to be in engagement with the upper edges 6 of a lower pallet when the pallets are stacked vertically. In the illustrated structure, the pallet 1 is a generally rectangular structure and the marginal edge portion 8 and the bottom wall member 10 thereof are continuous along each edge of the pallet 1 whereby there is a space formed between the bottom wall member 10 of an upper pallet and the load supporting platform 2 of a lower pallet. The space is sized to permit the free ends of the arms or prongs of a conventional fork lift to move into the space between the pallets to be separated and then into engagement with the sloped end portions 11 of the ribs 4 or 5 to thereby separate the adjacent pallets.

A suitable dye may be mixed with the structural foam plastic to color code the pallets whereby specific types of merchandise may be loaded on pallets of a specific color.

It is noted that the ribs and walls of the pallet are designed to have a substantially equal thickness, consistent with proper draft for removal from the mold, whereby all portions of the pallet 1 will have substantially the same cooling time and thereby a minimum cooling time within the mold for the particular wall thickness.

FIG. 6 illustrates means for forming a composite structure including reinforcing material in the grid structure defining the load supporting platform 2. The reinforcing material is illustrated as rods or strands 20 and 21 positioned adjacent upper and lower edges 6 and 7 respectively of the ribs 4 and 5 and enclosed within the plastic material. The rods or strands 20 and 21 may be any suitable material having high tensile strength and a good bond to the foamed plastic, such as metal rods or strands or strands of glass fibers. This reinforcing increases the load carrying ability of the pallet and reduces the deflection from such load.

It is to be understood that while I have illustrated and described certain forms of my invention, it is not to be limited to these specific forms or arrangement of parts herein described and shown.

Claims

What I claim and desire to secure by Letters Patent is:

1. In a one piece, molded, nestable pallet:

a. a platform having a load carrying top surface;

b. said platform being a grid structure formed of a plurality of ribs individually presented edge-wise to said top surface, said ribs intersecting each other at a plurality of intersections and united to each other at said intersections, said ribs defining openings therebetween normal to said top surface, said ribs being wider adjacent said top surface and tapering downwardly;

c. a plurality of spaced apart, hollow legs having an open top and side walls extending downwardly from said top surface, said leg side walls being united with ribs intersecting same, said leg side walls being connected to adjacent side walls and connected at lower ends with a bottom wall, said legs side walls each sloping downwardly and inwardly from said top surface to a size whereby legs of one pallet will enter the open top of the hollow legs of a lower pallet for verticle nesting; and

d. a marginal edge portion extending around the periphery of said grid structure and having at least one edge rib supported on end portions of the ribs of said platform, said edge portion having a depth less than said grid structure to provide a space between the bottom edge of edge portions of one pallet and the top surface of a next lower pallet in a stack.

2. The pallet structure as set forth in claim 1 including:

a. a bottom wall member connecting a lower portion of said edge rib and adjacent ribs of said grid structure thereby providing an edge structure with a continuous bottom wall surface around the grid structure from the edge rib to adjacent parallel ribs.

3. The pallet structure as set forth in claim 2 wherein end portions of ribs normal to a respective edge rib have lower edges sloping downwardly and inwardly from a rib that is next adjacent to and parallel to said respective edge rib.

4. The pallet structure as set forth in claim 3 wherein:

a. said leg members each depending below the grid structure a distance greater than the height of the ribs of the grid structure to space the grid structures when pallets are stacked vertically with a greater spacing of edge portions thereof;

b. said bottom wall members of said leg members each have an aperture therethrough; and

c. said bottom wall members of said edge portion each have an aperture therethrough between each of said ribs extending between said edge rib and the adjacent parallel rib.

5. The pallet structure as set forth in claim 2 wherein:

a. the pallet structure is generally rectangular;

b. said leg members are spaced apart to permit ingress of arms of a fork lift, said leg members being positioned to permit ingress from each side of the pallet structure;

c. said bottom wall member of said edge portion is positioned above said lower edges of said ribs, said bottom wall member being continuous along each edge of the pallet structure; and

d. said ribs each have opposite end portions sloped between said bottom wall of said edge portion and a lower edge of an adjacent rib parallel to the respective edge rib.

6. The pallet structure as set forth in claim 5 wherein:

a. said ribs and wall of the grid structure, leg members and edge portion are integral and of structural foam plastic.

7. The pallet structure as set forth in claim 6 including reinforcing material in said grid structure, said reinforcing including elongate members extending longitudinally of the ribs of the grid structure to increase the strength and reduce the deflection thereof.