US 3695188 A
Description (OCR text may contain errors)
United States Patent Granatstein 51 Oct. 3, 1972  PALLET OF MOLDABLE OR THERMO- FORMABLE MATERIAL  Inventor: David Lloyd Granatstein, Toronto,
Ontario, Canada  Foreign Application Priority Data March 19, 1971 Canada ..108178  US. Cl .Q ..108/58  Int. Cl. ..B65d 19/18  Field of Search ..108/51-58; 280/21  References Cited UNITED STATES PATENTS 3,140,672 7/1964 De Luca ..108/53 3,526,195 9/1970 Maryonovich 108/53 3,511,191 5/1970 Barry, Jr. et a1. ..108/58 3,167,341 l/1965 Higgins ..108/58 3,172,374 3/1965 Allen ..108/51 3,338,589 8/1967 Barton et al. ..280/21 3,424,110 1/1969 Toot 108/53 3,481,285 12/1969 Yellin ..108/58 3,587,481 6/1971 Kincade ..108/53 3,526,195 9/1970 Maryonovich 1 08/53 FQREIGN PATENTS OR APPLICATIONS 834,477 6/1960 Great Britain 108/ 5 1 Primary Examiner-Bobby R. Gay Assistant Examiner-Glenn O. Finch Attorney-George A. Rolston  ABSTRACT A pallet which may be fabricated from a mouldable or thermo-formable material, and which possesses rigidity. over the entire load bearing surface, is light in weight and easy to manufacture. The pallet is preferably formed of a single sheet of mouldable or thermo-formable material incorporating a plurality of legs depending from its lower surface so as to space the same above the floor to permit entry of any suitable lifting mechanism thereunder, and is provided with a network of interconnecting ribs projecting downwardly from the lower surface of the pallet and forming a network of corresponding channels in the load supporting upper surface of the pallet, the ribs and channels being arranged in a particular pattern, characterized by an absence of channels crossing one another, and at least one of said channels meeting each leg.
7 Claims, 5 Drawing Figures PATENTED 0m 3 I972 SHEET 1 [If 2 DAVID L. GRANATSTEIN PATENTED 0m 3 1972 SHEET 2 OF 2 DAVID L. GRANATSTEIN PALLET OF MOLDABLE OR THERMO- FORMABLE MATERIAL This invention relates to a warehouse pallet for use with a lift truck or other similar mechanism.
BACKGROUND OF THE INVENTION The most common pallet made today is made of wood. Wooden pallets suffer from many faults. They require several different operations to construct them, are very heavy and expensive, and suffer from splintering, rotting, weather degradation and short lifespan. In addition, they cannot be sterilized for use in the food industries.
Plastic pallets which do not suffer these faults have now come onto the market, but these too have their shortcomings. The pallet described in Canadian Patent No. 805,979 obtains maximum strength from a sheet of plastic at the expense of extensive spaces on the load bearing surface, making it unsuitable for supporting a load of small containers. The pallet described in Canadian Patent No. 746,752 suffers a lack of edgewise and diagonal rigidity due to long uninterrupted channels. The pallet described in Canadian Patent No. 633,024 suffers the same lack of rigidity.
The present invention has overcome the faults of the prior art pallets, by an improved design. The pallet shows rigidity over the entire load-bearing surface, is lightweight, can be made nestable to stack in a smaller space, can be manufactured inexpensively and easily, does not splinter or break, can be sterilized, and has a load-supporting surface which is relatively free of large open spaces, making it suitable for supporting all sizes of loads.
More specifically, this invention provides a pallet which can be fabricated from a mouldable or thermoformable material, and which possesses rigidity over the entire surface.
BRIEF SUMMARY OF THE INVENTION The pallet of this invention comprises an upper load supporting surface, a plurality of legs depending from a lower surface, spaced to allow fork-lift entry from at least one side, a network of interconnecting ribs projecting from said lower surface and forming a network of corresponding channels in said load-supporting upper surface, and a continuous rib projecting from said lower surface, forming a corresponding channel in said upper surface around and forming the perimeter of said pallet. The above-mentioned advantages are achieved by having said network of channels which meet the following conditions:
a. no channels cross each other b. every channel meets at least one other channel,
but no more than three channels meet at any point c. some channels meet a channel which forms the perimeter of the pallet perpendicularly or at a lesser angle, and
d. at least one channel meets each leg.
Any number of legs necessary to support the load may be used. In a preferred embodiment, the pallet has nine legs arranged to accept a lift truck from all four sides.
The pallet may have three legs running the length of the structure. This arrangement will allow two-way entry, but by cutting appropriate holes through the thickness of the legs, four-way entry is possible.
The legs may be formed integrally with the load-supporting platform or may be fabricated separately and attached to the underside of the platform. Additionally, where there is a possibility that full pallets may be stacked one on top of another, and there is danger that the pallet legs may dig into and damage the load below, a bottom platform or stage may be attached to each leg.
Any mouldable or thermo-formable material may be used in construction of the pallet. Preferred materials are high density polyethylene both non-reinforced and glass fiber reinforced, ABS, and polystyrene.
Preferred methods of construction are injection moulding and vacuum forming. In the case of vacuum forming, where the legs are formed integrally with the body of the pallet, these legs will be hollow projections from the bottom surface of the pallet. If no bottom stage is attached, this pallet will be nestable.
These various advantages will become apparent from the following description, with reference to the drawings which illustrate the preferred embodiments of the invention.
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a lower plan view of the underside of a pallet using a network of interconnected channels in the configuration of interconnected hexagons;
FIG. 2 is an enlarged lower plan view of a portion of the underside of the pallet shown in FIG. 1;
FIG. 3 is a lower perspective illustration of a portion of the underside of the pallet shown in FIGS. 1 and 2, partially cut away to reveal its construction;
FIG. 4 is a lower plan view of a further embodiment of the invention showing the underside of a portion of a pallet using a combination of squares, hexagons, and other multi-sided figures, for the configuration of the channels; and
FIG. 5 is a partial side elevational view of a further embodiment of the invention showing the attachment of a lower load-bearing surface.
DETAILED DESCRIPTION OF SPECIFIC EMBODIMENT Referring to FIG. 1, a pallet 10 is shown having channels or ribs 11 meeting a perimeter 12 at an angle shown as 13 and channels 11 meeting the legs 14 as at 15. Three channels meeting at a point are shown as at 16. Note that there are no crossing channels.
Referring more particularly to FIGS. 2 and 3, it will be seen in this preferred embodiment of the invention that the entire pallet 10 is formed of a single sheet of thermo-formable material, such as acrylonitrile-butadiene-styrene, high density polyethylene, glass fiber reinforced high density polyethylene and polystyrene or any other suitable sheet thermo-formable material. The ribs 11, and perimeter 12 and the legs 14, are all formed according to this preferred embodiment of the invention, by vacuum forming, or some other similar technique in which the sheet of thermo-formable material is first of all heated up to a thermo-formable temperature, and is then drawn downwardly, either into or over a die (not shown), thereby forming the various features mentioned.
It will, of course, be understood that in such forming process, the spaces between adjacent channels or ribs 11 will be constituted by continuous areas or webs of thermo-plastic material, indicated generally as 17, the
shape of the webs 17 corresponding to the shape defined by the ribs 11 surrounding such area or webs.
' Thus, where the ribs 11 define a generally hexagonal shape, then the webs l7 defined within such ribs will obviously be of hexagonal shape. The upwardly directed surface of the webs 17 will define the upper or load-bearing surface of the pallet l0, and the downwardly directed surface of the ribs 11 will define the lower surface of the pallet 10, which is normally engaged by any suitable lifting mechanism such as a fork lift truck or the like.
It will, of course, be appreciated that the legs 14 must necessarily depend downwardly from such lower surface in order to support the same above the floor, or above the next adjacent load of products so that the forks, or other lift mechanism may readily be inserted into the space defined thereby. As shown in the illustration, the legs 14 are of generally frusto-conical shape, but obviously, may be of any other suitable shape.
Referring now to FIG. 4, a further embodiment of the invention is shown, in which the ribs 11 are arranged in a somewhat different pattern, some of the ribs defining hexagonal spaces, and other ribs defining a rectangular space, and still other ribs 11 defining other geometrical shapes.
Referring now'to FIG. 5, a further embodiment of the invention is shown in which a lower supporting member or members 18 are provided suitably fastened to the underside of the legs 14. Supporting members 18 may be three wooden runners or one continuous platform 18 if desired.
However, in the majority of cases, it will not be found necessary to add the additional lower supporting members. In addition, in the embodiment of FIGS. 1 to 4, it will be found that pallets according to the invention may be nested one above the other. This additional advantage flows from the fact that both the leg members 14 and the channels 11 and the perimeter 12 are all formed by indenting portions of the thermo-formable sheet material in a generally tapering manner, so that the channels and legs of one pallet can fit at least partially within the corresponding indentations in a lower pallet in a nested stack.
According to the invention, it has been found that by the use of the channels or ribs 11 as disclosed, in which no channels actually cross one another in the formation, that a greatly increased degree of rigidity may be achieved.
The absence of channels crossing at right angles, clearly distinguishes this invention over the prior art, and produces the surprising result of greatly increased rigidity which was not present in prior art structures.
The foregoing is a description of a preferred embodiment of the invention which is given here by way of example only. The invention is not to be taken as limited to any of the specific features as described, but comprehends all such variations as come within the scope of the appended claims.
What I claim is:
l. A pallet formed from a mouldable or thermoformable material and having edgewise, transverse and diagonal rigidity, and which includes:
a panel having a load-supporting top surface and an undersurf ce;
a plurality 0 legs depending from said undersurface of said panel, said legs being mutually spaced apart so as to allow entry of the arms of a fork lift between said legs from at least one side of said pallet;
a continuous perimeter rib projecting from said undersurface of said panel substantially completely about the perimeter thereof and forming a corresponding perimeter channel in said, top surface; and network of interconnected ribs projecting from said undersurface of said panel and forming a network of corresponding channels in said load-supporting top surface of said panel, said network of corresponding channels being formed so that no said channels cross each other, so that each and every said channel meets at least one other said channel but so that no more than three said channels intersect at any one point, so that at least some of said channels meet said perimeter channel, and so that at least one said channel meets each and every said leg.
2. A pallet as claimed in claim 1, which pallet is formed from a single sheet of mouldable or thermoformable material, and in which said legs are formed as integral hollow downward projections of said sheet from said undersurface thereof.
3. A pallet as claimed in claim 1 in which said legs are spaced so as to allow entry of the arms of a fork-lift therebetween from each of four sides of said pallet.
4. A pallet as claimed in claim 1 and which additionally comprises a bottom stage fastened to lower ends of said legs.
5. A pallet as claimed in claim 1 in which said network of intersecting ribs is provided essentially as a plurality of interconnected hexagons.
6. A pallet as claimed in claim 1 in which said pallet is formed from at least one mouldable or thermoformable material selected from the group consisting of ABS, high density polyethylene, glass fiber-reinforced high density polyethylene and polystyrene.
7. A pallet as claimed in claim 1 in which said ribs and the corresponding said channels as well as said legs are formed integrally with said panel from a single sheet of said mouldable or thermo-formable material, said ribs, channels and legs so being constituted by downwardly indented portions of said sheet and each said downwardly indented portion of said sheet having a tapered cross-sectional configuration whereby said pallet may be nested with other like pallets one above the other with said ribs and legs of said pallet nesting at least partially within corresponding indented portions of the nest subjacent pallet.