Molded Pallet

Abstract

Resin impregnated wood fibrous material is molded to form a rectangular deck member and a set of separate elongated hollow leg members. The deck member has a generally uniform wall thickness and defines parallel spaced downwardly projecting reinforcing ribs, and the side walls of each of the leg members have teeth-like projections which extend upwardly between the ribs. The leg members are spaced laterally across the deck member and are secured to the underneath surface of the deck member by a waterproof adhesive. The leg members have outer surfaces perpendicular to the deck member to provide for storing loaded pallets within a rack, and define longitudinally spaced recesses to provide for four-way entry by a fork lift truck. The bottom wall portion forming each recess is spaced from the underneath surface of the deck member to define a longitudinally extending chamber within each leg member for receiving an optional rigid longitudinally extending reinforcing member.

Description

BACKGROUND OF THE INVENTION

In the art of material handling pallets, there has been considerable effort to produce a pallet which is less expensive than the standard pallet constructed of lumber and which provides substantially the same strength, durability, and other desirable characteristics. For example, the pallet shown in U.S. Pat. No. 3,140,672 is molded from a wood fibrous material impregnated with resin, and the pallet disclosed in U.S. Pat. No. 3,199,469 is molded of a thermoplastic material which may have a wood filler. Other molded pallets are shown in U.S. Pat. Nos. 3,187,691, 3,359,929 and 3,481,285.

It has been found desirable for any pallet to provide a number of features. For example, a pallet should not only be durable, warp resistant and provide substantial strength, it should also be inexpensive and lightweight in construction. It is also desirable for a pallet to be nestable, moisture resistant and have smooth exposed edges and surfaces. In addition, both the top and bottom surfaces of the pallet should be of substantial area so that the articles stacked on the pallet are not subject to undesirable stresses, and loaded pallets may be stacked without the legs of the pallets damaging the articles on the pallet below.

A bottom surface of large area is also desirable on a pallet for transporting the pallets along a roller conveyor where the rollers are spaced, for example, at a distance of 9 inches. Another important feature on a pallet is for the edge surfaces to be substantially perpendicular to the deck of the pallet so that loaded pallets may be stored within a rack having opposed support tracks or flanges. It is also desirable for a pallet to be conveniently constructed in various widths, for example, between 31 inches and 40 inches. Heretofore, molded pallets have been constructed with one or more molds or dies for each size or design.

After a careful study of the molded pallets disclosed in the above patents, it is apparent that each of the pallets does not provide one or more of the desirable features mentioned above.

SUMMARY OF THE INVENTION

The present invention is directed to an improved molded pallet which provides all of the aforementioned features and advantages and, in addition, provides for increasing the strength and rigidity of the pallet if desirable for handling an unusually heavy load. In accordance with a preferred embodiment of the invention, a generally flat deck member is molded from a resin impregnated wood fibrous material and includes longitudinally spaced parallel ribs which project downwardly. The deck member has a generally uniform wall thickness forming a corrugated cross-sectional configuration with laterally extending parallel spaced grooves within the upper surface of the deck member.

A plurality of elongated hollow leg members are each molded of the same resin impregnated wood fibrous material, and the side walls of each leg member have teeth-like projections which extend upwardly between the ribs on the underneath surface of the deck member. The leg members are arranged in laterally spaced relation and are bonded to the underneath surface of the deck member by a suitable water resistant adhesive so that a watertight chamber is formed within each leg member. The interfitting relation between the teeth-like projections on each leg member and the underneath surface of the ribbed deck member provides a substantial area for adhesive bonding and also provides for a positive interfitting connection between the leg and deck members.

The outer side wall and the end surfaces of the leg members are substantially perpendicular to the deck member, and the inner side wall surfaces are slightly inclined. Each of the leg members defines longitudinally spaced recesses to provide for four-way entry of a fork lift truck, and the wall portion defining each recess is spaced from the underneath surface of the deck member so that a rigid plank-like reinforcing member may be inserted within each leg to provide additional strength and rigidity.

Other features and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a pallet constructed in accordance with the invention and showing the top surface;

FIG. 1A is a fragmentary perspective view showing a modification of the pallet in FIG. 1;

FIG. 2 is another perspective view of the pallet in FIG. 1 and showing the bottom surfaces of the pallet;

FIG. 3 is an exploded section taken generally on the line 3--3 of FIG. 1 and with portions broken away;

FIG. 4 is a similar exploded fragmentary section taken generally on the line 4--4 of FIG. 3;

FIG. 5 is an exploded fragmentary perspective view showing a modification of the pallet in FIGS. 1 and 2;

FIG. 6 is a fragmentary perspective view showing another modification of the pallet;

FIG. 7 is an exploded perspective view showing a further modification of the pallet in FIGS. 1 and 2;

FIG. 8 is a schematic elevational end view showing another modified form of the pallet in FIGS. 1 and 2; and

FIG. 9 is a schematic end view of a plurality of pallets of FIGS. 1 and 2 stacked in offset nested relation.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The pallet shown in FIGS. 1 and 2 is molded in sections from a resin impregnated wood fibrous material, preferably using a molding technique perfected by Werzalit-Pressholzwerk of 7141 Oberstenfeld bei Stuttgart, West Germany and promoted in the United States under the trademark "Werzalit." The first section of the pallet includes a generally flat rectangular deck member 15 having a generally uniform wall thickness and defining longitudinally spaced and downwardly projecting parallel ribs 16. As a result of the uniform wall thickness, each of the ribs 16 defines a laterally extending groove 18 within the flat upper surface 20 of the deck member. The opposite end portions 22 of the deck member 15 form rails having a thickness corresponding to the thickness of the center portion of the deck member including the ribs 16. Thus the deck member has a uniform corrugated cross-sectional configuration across its width and transversely to the ribs 16, and could possibly be extruded with sufficiently large equipment.

The other sections of the pallet include a set of elongated hollow end and center leg members 25 and 26 respectively, each of which is molded of resin impregnated wood fibrous material in the same manner as the deck member 15 and has a generally uniform wall thickness. Each of the leg members 25 and 26 includes a bottom wall 28, opposite flat side walls 30 and 31 and flat end walls 32. Two longitudinally spaced recesses 34 are formed within each bottom wall 28 by an inverted U-shaped wall portion 36 which extend upwardly approximately one-half the height of the leg member. The side walls 30 and 31 of each leg member 25 include a plurality of longitudinally spaced and upwardly extending teeth-like projections 37 which define correspondingly spaced recesses or cavities 38.

The projections 37 and the cavities 38 conform to the configuration of the underneath surface of the deck member 15, and each of the leg members 25 and 26 is secured to the underneath surface of the deck member 15 by a suitable water resistant adhesive to form a substantially watertight chamber within each of the leg members. As shown in FIG. 4, the outer surface of the outer side wall 30 of the two outermost leg members 25 and the end walls 32 of each leg member extend substantially perpendicular to the deck member 15. The inner side wall 31 of the two leg members 25 and both of the side walls of the center leg member 26 are slightly inclined or tapered to facilitate molding each of the leg members as an integral body. Preferably, the projections 37 along the tapered side walls 31 also extend or curve outwardly of the leg members to provide additional reinforcement and a greater surface area for gluing or bonding the leg members to the underneath side of the deck members. These extended projections 37 also eliminate sharp corners within the grooves between the ribs 16 so that foreign matter does not tend to accumulate.

Referring to FIG. 1A which shows a modification of the pallet in FIGS. 1-4, the end portions 22 of the deck member 15 are provided with three laterally spaced slots or recesses 42 which receive an extended upper lip or edge portion 43 of the end wall 32 of the corresponding leg member. This modification has the advantage of providing an increased surface area for adhesive bonding the end walls 32 of each leg member to the underneath surface of the deck member 15 and to provide a somewhat more positive interfitting connection between the leg members and the deck member.

As mentioned above, the recesses 34 are defined within each of the leg members 25 and 26 by a bottom wall portion 36 (FIG. 7) which is spaced from the underneath surface of the ribs 16 to define within each leg member a chamber or cavity which extends the full length of the leg member. To increase the longitudinal bending strength of the pallet shown in FIGS. 1 and 2, an elongated plank-like reinforcing member 50 (FIG. 7) may be inserted within each of the leg members 25 and 26. Preferably, the member 50 is formed of plywood and has a thickness which corresponds to the distance between the underneath surfaces of the ribs 16 and the upper surfaces of the bottom wall portions 36 so that the member 50 is sandwiched between the surfaces.

Referring to FIG. 5 which shows another modified pallet of the invention, the opposite end portions of the pallet shown in FIGS. 1 and 2 may each be reinforced by a metal frame 55 consisting of a laterally extending angle member 56 rigidly secured to angle corner posts or legs 57. The angle member 56 extends into a corresponding laterally extending slot 58 formed within the end portion 22' of the deck member 15', and the leg members 57 are secured to the outer corners of the molded leg members 25 by a set of suitable fasteners such as screws 59.

As shown in FIG. 6, notches 62 are formed within a set of laterally aligned projections 36 on the side walls 30 and 31 of the leg members 25 and 26, and a laterally extending channel member 64 is inserted into the notches 62 adjacent the underneath surface of the deck member 15. The channel member defines a laterally extending slot for receiving a suitable strap or band (not shown) for securing a load of cargo to the deck member 15. While only one laterally extending slot is illustrated in FIG. 6, it is to be understood that a plurality of longitudinally spaced slots may be employed according to the number of tie down bands desired. The channel member 64 provides for guiding the end of a band through the slot and cooperates with the ribs 16 to provide lateral rigidity and strength to the deck member 15.

In accordance with another embodiment of the invention, a molded deck member 15 (FIG. 8) is cemented or bonded to a set of elongated molded leg members 65 which are molded and formed in the same manner as the leg members 25 and 26 described above. The leg members 65, however, have a width approximately one-half the width of the leg members 25 and 26 and are particularly adapted for use on a pallet having a width less than the standard 40". As shown in FIG. 8, two of the leg members 65 may be joined back to back with their vertical side walls abutting to form the center leg member. As illustrated in FIG. 9, a number of the pallets shown in FIGS. 1 and 2 may be stacked in interfitting nested relation by offsetting alternate pairs of adjacent pallets having their load supporting surfaces in abutting relation. This substantially reduces the space required to store or transport a number of pallets.

From the drawings and the above description, it is apparent that a pallet constructed in accordance with the present invention provides the desirable features and advantages mentioned above. For example, the combination of the deck member 15 with parallel spaced ribs 16 and the interfitting elongated hollow leg member 25 and 26, which are separately molded from resin impregnated wood fibrous material and are bonded together with adhesive, provides for a lightweight pallet of substantial strength and with smooth edges and surfaces. As a result of the relatively narrow parallel spaced ribs 16, the area of the top surface 20 is approximately 75 percent of the total area of the deck member, thereby providing a load supporting surface of substantial area.

The leg members 25 and 26 provide additional important features. That is, the flat pads formed by the bottom walls 28 of the leg members provide a bottom supporting surface of substantial area in the order of 39% of the total area of the deck member 15. This large bottom supporting area is desirable to prevent damage of the load when two or more of the loaded pallets are stacked one upon the other and to provide for conveying loaded pallets along a roller conveyor. As indicated in FIG. 9, the leg members 25 and 26 also provide for nesting of the pallets, and the outer perpendicular walls 30 and 32 of the leg members enable a loaded pallet to be stored in a rack having opposed flanges which engage the outer edge portions of the bottom walls 28. The wide flat bottom wall 28 of the center leg member (FIGS. 2 and 8) also provides for lifting a loaded pallet with lift truck forks which engage only two of the leg members and without the loaded pallet tipping as occurs with conventional four-way entry wood pallets.

The construction of the separate deck and leg members also provides for producing pallets of various widths. That is, as a result of the uniform longitudinal cross-sectional configuration of the deck member 15, the deck member may be cut according to a desired width after which the leg members are secured to the underneath surface of the deck member as shown in FIGS. 1-4. As mentioned above, to construct a relatively narrow pallet, the invention provides for using narrower leg members 65 (FIG. 8) and attaching two of the leg members 65 together to form a unitary center leg member while retaining the ability to nest the pallets in a manner as shown in FIG. 9.

The modifications shown in FIGS. 5-7 provide additional features. The end frames 55 not only provide for lateral reinforcement of the deck member 15 but also protect the end and corner surfaces of the pallet. The optional plank-like reinforcing members 50 enable the strength of the pallet to be conveniently increased in a longitudinal direction, and the channel members 64 (FIG. 6) provide for conveniently inserting tie down straps or bands under the deck member 15 and for increasing the strength in a lateral direction.

While the forms of pallets herein described constitute preferred embodiments of the invention, it is to be understood that the invention is not limited to these precise forms of pallets, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims. For example, it is within the scope of the invention to construct and locate the hollow molded leg members so that a peripheral edge portion of the deck member projects from the leg members if storage in a rack is not required and it is desirable to shrink-fit a plastic film over a load on the pallet.

Claims

What is claimed is:

1. A pallet comprising

a molded rectangular deck member forming a load supporting upper surface and including a plurality of substantially parallel spaced integral reinforcing ribs, said deck member having a substantially uniform wall thickness forming a corrugated cross-sectional configuration relative to said ribs and defining downwardly facing parallel spaced grooves,

at least two separate elongated molded hollow leg members arranged in spaced relation below said deck member and extending transversely of said ribs, each said leg member including a bottom wall forming a generally flat bottom surface and side walls projecting upwardly from said bottom wall, the upper portions of said side walls of each said leg member including teeth members projecting upwardly into said grooves and between said ribs,

said leg members each having at least one longitudinally extending said side wall inclined relative to said bottom wall, said leg members arranged to provide offset nesting of a pair of adjacent said pallets with said leg members disposed in interfitting relation, and

means for securing the upper portions of said side walls of each said leg member to the underneath surface of said deck member.

2. The pallet as defined in claim 1 wherein said deck member and said leg members each comprise a discrete unitary body consisting of resin impregnated wood fibrous material, and said securing means comprise an adhesive bonding said leg members to said deck member.

3. A pallet as defined in claim 1 wherein the outermost said leg members each has outer surfaces extending substantially perpendicular to said deck member to facilitate supporting said pallet on opposing horizontal flanges of a storage rack.

4. A pallet as defined in claim 1 wherein said deck member has a uniform cross-sectional configuration along its width to provide for locating said leg members at various laterally spaced intervals and thereby facilitate construction of pallets of different widths.

5. A pallet as defined in claim 1 wherein said bottom wall of each said leg member defines a set of longitudinally spaced recesses adapted to receive the forks of a lift truck.

6. A pallet as defined in claim 7 wherein each said recess of at least one of said leg members is defined by a wall portion spaced from the underneath surface of said deck member to define a longitudinally extending chamber within said leg member, an elongated rigid reinforcing member extending within said chamber, and said reinforcing member has a thickness corresponding substantially to the distance between said wall portions of said recesses and the underneath surface of said deck member.

7. A pallet as defined in claim 1 including means extending between two adjacent said ribs of said deck member to define a slot adapted to receive a tie down strap.

8. A pallet as defined in claim 1 including a rigid metal frame extending along at least one lateral edge of said deck member, and said frame includes leg portions positioned adjacent the outer corners of the outermost said leg members.

9. A pallet as defined in claim 1 wherein the center portion of said deck member is supported by a pair of said leg members each having a substantially perpendicular longitudinally extending side wall and a slightly inclined longitudinally extending side wall relative to said deck member, and said perpendicular side walls are disposed in adjacent relation.

10. A pallet as defined in claim 1 wherein said deck member has a substantially uniform wall thickness and a corrugated cross-sectional configuration transversely of said ribs, and each said leg member extends substantially the full length of said deck member.

11. A pallet as defined in claim 1 wherein at least one of said leg members includes substantially flat end walls, means defining recesses within the underneath surface of said deck member for receiving the upper portions of said end walls, and said securing means comprise an adhesive which extends into said recesses for securing said end walls to said deck member.