Pallet Structure With Self Locking Leg

Abstract

The pallet comprises a deck sheet to which is secured a plurality of spaced legs arranged in a pattern to permit handling of the pallet by a forklift truck or other material handling equipment. Each leg comprises a reinforced synthetic support which is preferably shaped like the frustum of a cone and which includes a flange area and locking slot at the upper end thereof. The pallet is formed by forcing the legs through openings in the deck sheet where the legs are automatically locked in position.

Description

BACKGROUND OF THE INVENTION

This invention relates generally to a pallet structure having a deck sheet or platform member formed from any convenient material such as wood, plastic, paper or any combination thereof, and a novel leg member formed from a synthetic material such as high density polyethylene, Fiberglas reinforced high density polyethylene or other ABS type materials. The term "ABS Materials" is used herein to define a group of engineering plastics which contain acrylonitrile-butadiene-styrene resins.

The invention relates more particularly to an improvement in pallets and deals with a pallet having in its preferred form, a deck sheet or platform member of corrugated paperboard or the like, and legs made from an injected-molded synthetic which can be produced at low cost and assembled with a minimum of effort.

Pallets are very commonly used in materials handling operations. In view of the fact that wooden pallets are quite expensive to produce, many such pallets are now being manufactured of paperboard or solid fiber. While pallets of this type are not as durable as wooden pallets, they are sufficiently less expensive so that they may be disposed of after use. Such an arrangement is particularly desirable where goods are being shipped from a manufacturer to a distant point, as it eliminates the necessity of returning the empty pallets to the manufacturer. However, this situation, where the pallets have only one useful life is not always the case, and, to present a solution for both the requirements of a reusable pallet and a disposable pallet the hereinafter described invention was developed.

Applicant discovered that most loads applied to pallets were well distributed and that the limiting factor in weight support was the ability of the leg structure to support a load. Accordingly, a low cost, easily manufactured, novel, one piece leg structure, having maximum load carrying ability for its weight and cost, was developed.

Moreover, applicant further discovered that most single faced nestable pallets failed when any one leg collapsed. These failures occurred when the leg proper failed, and the attachment flange bent, or, the leg structure became detached from the platform because of poor attachment, thus increasing the load in unbalanced proportion on the remaining leg structures. Accordingly, applicant developed an attachment structure on the upper end of the pallet leg to overcome the problems with the prior art by uniformly loading the leg portion of the leg structure and mechanically locking the leg structure to the platform automatically upon assembly and without any attendant manipulation.

BRIEF SUMMARY OF THE INVENTION

Pallets of the class to which this invention relates are used extensively for storing, handling and transporting numerous kinds of goods. Essentially, they are formed of a platform or deck sheet and a plurality of legs, the legs being spaced apart to accommodate the fork arms of a lift truck extending under the platform, preferably from any side of the platform. When not loaded or otherwise being used, they are usually stacked, and for some business arrangements, the empty pallets are required to be returned to the supplier of the shipped goods.

Various pallet structures have been proposed and many have been put to use which are adapted to be nested so as to occupy less storage space and less return shipping volume, but none have been known to encompass all of the features of the pallet structure of the present invention.

Since the novel pallet of the herein described and claimed invention is formed in its preferred embodiment from a combination of paperboard and plastic, applicant has made use of two inexpensive yet extremely strong raw materials. In addition, by arranging for the construction of the pallet without tools, fasteners, or machinery of any kind, applicant has further provided a pallet structure which can be set up with a minimum of effort and skill. Accordingly the novel pallet of the present invention could readily be used only once then thrown away; used and stored in nested condition for reuse or return to the supplier; or, used and then disassembled for other use or return to the supplier.

A general object of this invention is to provide a pallet structure which is simple and rugged in construction, reliable in service and economical to manufacture.

Another object of the present invention is to provide in one form an inexpensive pallet in which the legs thereof are made of a high strength synthetic material and the platform portion thereof is made of low cost paperboard.

A second object of the present invention is to provide a pallet construction which may utilize for example wood, plastic, paper or any combination thereof for the platform, and polyethylene, Fiberglas, or any ABS material for its leg construction.

A further object of the present invention is to provide a pallet construction wherein the component parts thereof may be shipped separately for assembly at the point of use.

An additional object of this invention is the provision of a novel pallet leg construction which includes an automatically locking feature adjacent the flanged upper end thereof for securely fixing the pallet leg to the pallet platform.

A feature of the invention is the provision of a pallet platform having a plurality of openings therein which accommodate tapered pallet legs with locking slots near the upper flanged edges thereof. The locking slot in each pallet leg is somewhat smaller in diameter than the diameter of the upper portion of the leg, and, it is a great deal smaller in diameter than the flange at the extreme upper edge of the leg. The vertical height of the locking slot is substantially the same size as the thickness of the pallet platform being used. The flanges have very little vertical thickness, but they are fairly wide so as to offer adequate support for the load on the pallet.

Other features and advantages of the novel pallet in accordance with the present invention will appear in the following part of the specification wherein the details of construction and manner of assembly is described in more detail.

BRIEF DESCRIPTION OF DRAWING

FIG. 1 is a plan view of the top surface of a supporting platform with the legs affixed in position;

FIG. 2 is a side view of the pallet structure of FIG. 1;

FIG. 3 is a detailed view of one pallet leg as assembled with the support platform, and;

FIG. 4 is a vertical cross section of one of the preferred pallet legs.

DETAILED DESCRIPTION

Referring to the drawing in greater detail, the pallet shown in FIG. 1 is designated generally by reference numeral 10. It comprises a flat platform or deck sheet 11 and a plurality of legs 13 which are adapted to be frictionally received in openings cut from the platform 11. The platform may take any desired form, but it is preferred that either a corrugated paperboard or solid fiberboard sheet be used for the sake of cost, convenience and weight saving. When corrugated board is used, the platform may be formed from a single conventional double faced board having any desired flute size, or any combination of sheets and flutes as long as the thickness of the platform does not exceed the vertical dimension of the locking slot in the leg structure.

The pallet platform includes a plurality of openings 20 extending therethrough so that the legs 13 might be pressed into the openings to be locked in position. Openings 20 in platform 11 are sized to be slightly smaller than the upper end 16 of the pallet leg but approximately equal in diameter to the locking slot 17 in pallet leg 13. This relative construction permits the pallet leg 13 to be forced into the opening 20 until the periphery of opening 20 fits snugly into the slotted area 17 of the pallet leg. When this assembly takes place, the edges of the opening 20 are only slightly distorted and the platform opening 20 "pops" into locking position in the slot 17.

The pallet illustrated in FIG. 1 is shown as having five openings 20 and legs 13, which are spaced apart throughout the area of the platform 11 to accommodate the fork lift arms of a lift truck (not shown) extended between the legs, preferably from any edge of the platform, for lifting the platform. However, it should be understood that a pallet as constructed according to this invention could have any number of legs desirable. As an example, a standardized pallet having as many as nine openings for legs could be used. This pallet could then accommodate selectively as few as four legs or as many as nine legs placed in the respective openings in accordance with the load to be carried.

The legs 13 are preferably formed by injection molding of high density polyethylene or fiberglass reinforced high density polyethylene although synthetics of ABS materials might be used. The legs are of hollow construction having a relatively thin wall thickness, and are of frustoconical configuration, each having a sidewall 18 and a flat bottom wall 14. The upper end of the legs 13 include the leg end 16, an indented locking slot 17 and a load supporting flange area 15. The illustrated pallet platform 11 is made from corrugated paperboard and is prepared separately from the legs 13.

Since the legs are of a hollow frustoconical shape, they can be stacked in nested configuration prior to use, or assembled with the platform 11 and then stacked as desired. Further, to provide additional strength to the legs, it is desirable to add reinforcing ribs to the inside of the leg walls during the molding process. An example of the reinforcing ribs are illustrated in FIG. 4.

FIG. 2 shows the assembled pallet with the legs 13 extending below the platform 11 and the flanges 15 above the platform 11. This figure illustrates clearly that the platform element 11 serves only to position and fix the leg members 13 in place. The load carrying elements of the pallet are clearly the leg members 13 with the flanges 15 serving to distribute the load throughout the respective legs.

FIG. 3 is an enlarged, detailed view of one pallet leg 13 in combination with the pallet platform 11. This figure illustrates a desirable taper to the outer peripheral edges of the upper load supporting flanges 15. Moreover, the close fitting relationship of the locking slot 17 and the thickness of the pallet platform 11 is shown.

FIG. 4 shows a typical vertical cross-sectional view of the pallet leg 13. The tapered outer walls 18 of the pallet leg are shown as extending from a relatively small lower portion or base 14 up to a somewhat larger upper end 16. The locking slot 17 is located above the pallet leg upper end 16 and spaced slightly below the flange element 15. The locking slot is obviously of smaller diameter than the upper end 16 since the periphery of opening 20 must fit into slot 17 to positively lock the leg in position. The relative size of the upper end 16 and locking slot 17 would be chosen in accordance with several different factors. For instance, in view of the fact that the upper end 16 should pass through the accommodating opening 20 in the pallet platform 11, while allowing the platform material to then extend as far as possible into the locking slot 17, the material used for the pallet platform would be a determining factor. A relatively flexible pallet platform material such as corrugated paperboard could be successfully employed with a rather wide difference between the diameter of the pallet leg 13 at its upper end 16 and the diameter of the locking slot 17. The corrugated paperboard would tend to flex as the pallet leg was forced through the pallet platform opening and then return to its prior shape upon encountering the smaller locking slot at 17. Ideally, using corrugated paperboard, the diameter of the locking slot 17 would be the same as the diameter of the platform opening 20 with the pallet leg diameter at 16 being much larger. Of course, the diameter of the base at 14 would be smaller than opening 20. However, with heavier platform material, the platform opening 20 would have to be made more nearly the same size as the pallet leg at 16. In an experiment performed with a corrugated paperboard pallet, when the load was situated off center and away from the legs, the platform flexed so that the adjacent openings 20 assumed an elliptical shape which tended to grip the legs 13 more securely than in the normal state.

In practice, the pallet forming materials could be shipped to the user in different containers for assembly at the point of use, or, preassembled. If unassembled, the pallet platforms 11 would be precut and stacked and the leg elements 13 would be premolded and stacked much like paper cups in a dispenser. The user would then be required only to select a platform member 11 and choose the selected number of pallet legs 13 to insert in the openings 20, then simply force each leg into a respective opening 20 until the leg became locked in position. This assembly could be performed at the point of use without fasteners either by hand or with machinery such as a jig or the like. Obviously only a small amount of skill or effort would be involved.

From the foregoing, it will be seen that a novel and convenient structure has been invented. While only a preferred embodiment has been illustrated and described in detail, it should be recognized that any practical departure could be made therefrom within the scope of the invention. Thus having described the invention and the preferred manner of construction and assembly, what is desired to be protected by Letters Patent is defined in the appended claims.

Claims

I claim:

1. A pallet structure comprising:

a. a platform member having a plurality of spaced openings therein for receiving a plurality of leg members;

b. a plurality of one-piece leg members for selective use in the spaced openings of said platform;

c. each of said leg members including upper and lower portions with a continuous flange element integrally attached to said leg members above the upper portions thereof and extending outwardly therefrom;

d. means integral with each of said leg members for locking said leg members in the selected openings;

e. said integral locking means comprising a continuous slotted area around the periphery of each leg member and located above the upper portion of each leg member and below the flange element thereof.

2. The pallet structure of claim 1 wherein:

f. the locking slot of each leg member is smaller in diameter than the upper portion of said leg member and larger in diameter than the lower portion of said leg member.

3. The pallet structure of claim 2 wherein:

g. the locking slot of each leg member is substantially the same diameter as the corresponding opening in said platform member.

4. The pallet structure of claim 3 wherein:

h. the locking slot of each leg member has a vertical height which is substantially equal to the thickness of the associated platform member.

5. The pallet structure of claim 4 wherein:

i. said leg members are of frustoconical shape with a flat bottom surface so as to be nestable with one another.

6. The pallet structure of claim 5 wherein:

j. said leg members include internal ribs for increased compression strength.