US 3610172 A
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Description (OCR text may contain errors)
United States Patent Primary ExaminerPaul R. Gilliam Attorney-Joseph Rossman ABSTRACT: The pallet construction comprises a single platform supported on spaced molded plastic pallet feet mechanically secured to the platform. Each pallet foot consists of two separate components adapted for packing and shipping comprising: (1 a circular tapered cup portion having a flange extending outside of the cup; and (2) an open circular locking ring consisting of a flange of the same size as that on the cup with a downwardly depending body portion rim which extends into the cup and which has a locking means cooperating with the locking means inside the cup. A variation utilizes means for attaching a second board or runner to the bottom of the pallet feet by having holes in the bottom of the feet with matching holes in the bottom board or runner, and using retaining fasteners therethrough.
PATENTED 0m 51971 SHEET 1 [1F 3 INVENTOR THOMAS P. WHARTON PATENTED um 512m SHEET 2 BF 3 INVENTOR THOMAS P. WHARTON Y B Z MM ATTORNEY PATENTEDUEI SIB?! 3.610.172
SHEET 3 BF 3 iiiiiiii f FlG.ll
INVENTOR THOMAS P. WHARTON ATTORNEY PALLET CONSTRUCTION SUMMARY OF THE INVENTION This invention relates to a pallet construction comprising a platform of corrugated fiberboard or other suitable board material such as solid fiberboard, plywood, or other sheet material with some degree of rigidity, supported on spaced molded plastic feet secured to the platform. The individual pallet feet are preferably formed of a separate molded plastic cup portion and a separate molded plastic locking ring which interlocks with the cup portion and retains the pallet foot on the platform. According to this invention several modified foot constructions may be used to support the platform. Also the assembled pallet construction may be modified by providing bottom runner strips or a second bottom runner platform attached to the bottom of the pallet feet to facilitate moving the pallet on a roller conveyor.
ILLUSTRATIVE EMBODIMENTS Details of illustrative embodiments of the invention are described in the following specification and accompanying drawings, wherein,
FIG. 1 is a perspective view of an assembled pallet made of corrugated fiberboard platform having die-cut holes in which individual pallet feet are retained;
FIG. 1A is a fragmental perspective view of a pallet foot in disassembled relation showing the cup portion positioned adjacent a die-cut at the lower face of a corrugated fiberboard pallet platform and the locking ring positioned above the upper surface of the platform before being inserted and locked in the mouth of the cup portion;
FIG. 2 is a plan view of the upper face of the locking ring;
FIG. 3 is a plan view of the cup portion of the pallet foot viewed from the mouth portion;
FIG. 4 is a vertical sectional view of the locking ring taken on line 4-4 of FIG. 2;
FIG. 5 is a vertical sectional view of the cup portion taken on line 5-5 of FIG. 3;
FIG. 6 is an enlarged fragmental vertical sectional view taken on line 6-6 of FIG. 1;
FIG. 7 is an enlarged fragmental vertical sectional view of a modified construction of the pallet foot;
FIG. 8 is a perspective view of a modified pallet assembly provided with spaced bottom runner strips retained on the spaced pallet feet;
FIG. 9 is a perspective view of another modified pallet assembly provided with a second bottom runner platform retained on spaced pallet feet;
FIG. 10 is an enlarged vertical sectional view taken on line l10 of FIG. 8;
FIG. 11 is a fragmental perspective view in disassembled relation showing the pallet construction shown in FIG. 10;
FIRST EMBODIMENT Referring to the drawings, FIG. 1 illustrates a pallet consisting of a platform 7 made of corrugated fiberboard of suitable dimension, for example 40x48 inches, which is provided with nine spaced circular die-cut holes each of which receives a plastic molded locking ring 11, shown in greater detail in FIGS. IA, 2 and 4 which is inserted and locked in the mouth of a mating cup 10 positioned at the lower face of the platform 7 and axially aligned with the die-cut circular holes. The detailed construction of the cup portion of the foot is shown in FIGS. 3, and 6. The interlocked relation of the locking ring II and cup portion is shown in FIG. 6. It will be seen that the free cut edges of the circular diecut holes 7a are frictionally retained and slightly compressed between the flange portion of the locking ring II and flange portion 12 of the cup portion 10. The cup portion 10 is preferably formed of a suitable molded thermoplastic or thermosetting material, for example high-impact polystyrene, polypropylene or high density linear polyethylene, which are inherently rigid but which have some degree of elasticity to permit mechanically engaged interlocking of the complemental locking elements provided in the locking ring and cup portion. As shown in FIGS. 5 and 6, the generally frustoconically shaped cup portion comprises downwardly tapered wall portions I8 and 19, and a bottom I having internal integral radially extending reinforcing ribs 2. The bottom is also provided with holes 6 to permit drainage in event water should accidentally collect in cup portion, and also if desired to permit insertion of attachment means for attaching bottom runners as will be described hereinafter in connection with FIGS. 8 to II. The holes 6 also serve to relieve suction when the plastic cup portion is ejected from a forming mold. The depressed central portion in the bottom of the cup portion, shown in FIG. 5, serves to recess the tail or nib of plastic material which often remains at the point-where the plastic material is injected into the mold; otherwise this nib would project down past the bottom surface of the cup portion.
The exterior surface of the bottom I of the cup portion 10 is provided with spaced continuous slightly projecting annular beads or protrusions 3, 4 and 5, shown in FIGS. 5 and 6, which serve as hearing areas when the pallet is supported on a supporting surface and they also serve to reduce slipperiness of the bottom surface of the cup when the assembled pallet is in use.
The interior upper portion of the body portion I8 is provided with an inwardly extending locking shoulder portion 16, shown in FIGS. 5 and 6, which terminates inupper rounded edge portion 15 of the cup flange and lower rounded locking nose portion 17. The upper body portion of the cup is provided with-an integral outwardly extending annular flange I2 which is provided on its upper surface with spaced continuous annular beaded portions 13 and 14 which serve to compressively engage contacting portions of the platform 7, as shown in FIG. 6, adjacent the die-cut holes 70. The annular beads may be replaced by suitable protrusions, or roughened areas, to increase frictional engagement.
Referring to FIG. 4, the open circular locking ring 11 comprises a downwardly tapered body portion 31 which has a smooth continuous interior surface terminating in a downwardly extending portion 30. Portion 30 slopes at the same angle as the cup wall and is colinear with it to permit stacking of cups assembled into pallets. The exterior surface of the body portion of the ring is provided with a continuous circular channel or locking groove 27 which terminates in an upper shoulder 26 and a lower locking nose portion 28. The lower free end portion 29 of the tapered body portion of the locking ring may be slightly thickened for imparting strength. The tapered body portion 31 of the locking ring 11 is provided with an integral flange extending outwardly at the top of the body portion. The upper surface of the flange 20 is flat and the lower surface is provided with spaced continuous annular protrusions or beads 21 and 22 which provide gripping means for compressively engaging contact portions of the platform 7 adjacent the die-cut holes 7a, as shown in FIG 6, adjacent to the die-cut holes 70. The annular beads may be replaced by suitable protrusions, or roughened areas, to increase frictional engagement.
As stated previously, the pallet platform 7 which is preferably made of corrugated fiberboard is provided with a plurality of suitable spaced die-cut circular holes at which the supporting feet are positioned as shown in FIG. I. The die-cut holes are of a predetermined diameter and congruent with the outer diameter of the body portion 31 of the locking ring I I so as to permit insertion of the body portion 31 of the locking ring 11 through the upper surface of platform as shown in FIGS. 1 and 6. The flange portions 20 of the locking rings II are adapted to rest upon and engage the upper surface portions of the platform 7 adjacent the holes 7a, as shown in FIG. 6. The flange portions I2 of the cup component 10 is positioned to bear upon the lower surface portions of the platform 7 adjacent to holes 7a in axial alignment with the locking ring 11. In assembling the cup 10 and ring 11, suitable pressure is applied downwardly on the locking ring 11 so as to engage the locking shoulder 16 of the cup portion within the locking groove or channel 27 of the locking ring. Since the cup and the locking ring are circular no specific alignment is required, permitting assembly to be performed easily and, if desires, with a simple machine; and furthermore no twisting or threading operation is required to perform the assembly. The dimensions of the channel 27 and shoulder 16 are predetermined so that they can be mechanically interlocked in the relation shown in FIG. 6. In this position the locking nose portion 28 of the locking ring 11 engages the locking nose portion 17 of the cup 10, and the shoulder 26 (see FIG. 4) of ring 11 abuts the edge portion 15 of the cup flange l2 and thus serves as a stop portion to limit the downward movement of the ring within the cup 10. At the same time the areas of the platform 7 adjacent the die-cut holes are slightly compressed between the flange portion 20of the locking ring and the flange portion 12 of the cup portion which are both of the same width. The annular beads l3, I4, 21 and 22 of the respective flanges also serve to mechanically engage the areas of the platform adjacent the die-cut holes. The locking means is designed so that the locking ring 11 cannot be readily disengaged from the cup portions either accidentally or manually, since the pallet is expendable and is not intended to be disassembled for reuse.
A specific exemplary embodiment of the plastic pallet foot described may consist of a molded plastic cup portion of 0.055 thicknes, body height 2% inches, top flange diameter inches, width of locking shoulder one-fourth inch, flange width one-half inch, and bottom diameter 3% inches. The molded plastic locking ring has a top flange diameter 5% inches, flange width one-half inch, body height three-fourth inch, width of locking groove one-fourth inch, and open bottom diameter 4 inches. The circular die-cut holes in the platform have a diameter 4% inches. These dimensions are given by way of example and are not intended to be in limitation of the invention.
The configuration of the pallet foot is predetermined so that the cup portion can be nested for packing and shipping; the locking ring can also be nested for packing and shipping; and the assembled cup and locking ring attached to the pallet platfonn permits nesting of completely assembled pallets.
ADVANTAGES OF THE INVENTION Pallets made wholly of wood, plywood, metal or plastic are relatively heavy and expensive and usually must be returned for reuse at considerable expense rather than being discarded. They often have the disadvantage that the fork of a fork lift truck can enter the pallet only in one direction, and they are not nestable. Pallets made completely of corrugated fiberboard are usually not strong, their pallet feet are not moisture resistance, and the labor to assemble such pallets is time consuming and expensive. The present invention utilizes the inexpensiveness of fiberboard and the strength of plastics so that pallets of this invention can be considered expendable. The assembled pallet of the present invention as well as the components of the pallet feet are nestable as explained previously. When the savings in shipping and storage space of empty pallets, in shipping cost due to the light weight and nestability, and in fabrication and assembly labor costs of the present pallet construction are taken into account, the economies are very impressive. Furthennore, the light weight and nestability of the present pallet permits more pallets to be available at the point of use and permits empty pallets to be handled by female labor. The separate components of the pallet construction can be easily and quickly assembled without special tools, either by the manufacturer or at the point of use.
The apparent advantages of this pallet construction are thus low cost, light weight, nestability, and adaptability to any size and shape of platform required by the user, and any number and location of pallet feet that may be desired by the user.
A family of pallet feet and locking rings can be provided to permit a selection of desired feet heights and platform thicknesses. For example, the illustrative cup is 2% inches high; others can be made of different heights but using the same locking ring. To accommodate pallet platforms of different thicknesses, several styles of locking rings can be made differing only in the dimension from its flange 20 to its locking groove 27.
The family of plastic cups of different heights and locking rings can be interchangeable by standardizing the size of the die-cut holes in the pallet platform. The sizes and strengths of the pallet platforms can be varied to suit the particular loads to be supported thereon. Thus, according to the present invention it is possible to select suitable assemblies of the plastic cup, locking ring and platform for particular needs.
SECOND EMBODIMENT As previously stated, the construction of the pallet feet and pallet assembly may be varied. One modification is illustrated in FIG. 7 wherein the molded plastic cup 65 is provided with an interior recessed annular groove or channel 67 adjacent the open mouth of the cup which extends a short distance below the mouth. The downwardly tapered cup 65 has an integral flange 66 extending outwardly adjacent the mouth. The open molded locking ring 60 comprises a downwardly tapered body portion 63 which has an integral flange 61 extending outwardly at the top mouth portion. The lower end of the body portion is reduced in thickness to provide an annular flange portion 68 of suitable dimensions to be telescopically received in groove 67 of the cup and thus form a lap joint. The contacting areas of the lap joint may be bonded together with plastic cement or an autogenous seal may be produced by thermowelding same with high frequency or dielectric heat.
OTHER EMBODIMENT Modified pallet constructions are illustrated in FIGS. 8 to 11, wherein bottom runner strips or bottom runner platforms are attached to the pallet construction shown in FIG. I. The runners may be spaced strips 8 of corrugated fiberboard, solid fiberboard, or other suitable board material, as shown in FIG. 8; or a single bottom platform 4 of spaced corrugated fiberboard or suitable board material, coextensive with the upper platform 7 as shown in FIG. 9. The runner strips 8 are of a length of about the width of the upper platform 7. The bottom runners are provided die-cut holes 33 for receiving therethrough fastening means comprising spaced frustoconically shaped fastener heads 32 carried on supports 31 extending from the fastener base 30. The fastener heads 32 are adapted to be inserted through holes 6 in the bottom of the cup portion 10. The fastener heads 32 are preferably made of suitable soft flexible plastic or other elastomeric material so that they may be pushed through the holes 6 of the cup 10 and then can expand inside the cup into locking engagement with the bottom of the cup. As shown in FIG. 10, the slightly projecting base of the heads 32 frictionally engages the marginal portions of the bottom of the cup adjacent the holes 6. The construction and method of use of the different pallet constructions will be apparent from the foregoing detailed descriptions. Although Ihave shown and described several illustrative embodiments of my invention, changes may be made without departing from the scope of the invention as defined in the following claims.
I. A nestable molded plastic two-part foot adapted to be removably attached to a pallet platform of the type having openings for locating said foot and retaining same at the periphery of said openings, each said foot comprising in combination.
a. A nestable frustoconical cup having,
I. an open upper mouth and a bottom wall connected by a conical wall extending therebetween, said open mouth and said bottom wall being disposed in spaced apart planes orthogonal to the longitudinal conical axis of the cup, said open mouth being of greater diameter than the diameter of said bottom wall,
2. a flange extending radially outwardly from the substantially coplanar with said cup open upper mouth, said flange being of a width sufficient to underlie a portion of a pallet platform immediately adjacent a foot-receiving opening as aforesaid,
3. a locking shoulder extending radially inward from the inner surface of said conical wall adjacent to said open upper mouth and spaced thereaway from for a distance toward said bottom wall, said locking shoulder having a diameter less than the diameter of said open upper mouth,
b. a frustoconical locking ring having,
1. a conical wall terminating in upper and lower open mouths, said mouths being disposed in planes orthogonal to the longitudinal conical axis of the ring, said upper open mouth being of greater diameter than the diameter of said lower open mouth,
2. a flange extending radially outwardly from and substantially coplanar with the upper open mouth of said locking ring, said flange being of a width sufficient to overlie a portion of a pallet platform immediately adjacent to a foot receiving opening as aforesaid,
3. a locking shoulder extending radially outward from the outer surface of said locking ring conical wall adjacent to said open lower mouth and spaced therefrom for a distance toward said upper open mouth, the maximum diameter of said locking ring shoulder being slightly greater than the minimum diameter of the locking shoulder of said cup wall, the frustoconical walls of at least one of said cup and locking ring being radially deformable,
whereby, upon positioning said locking ring and cup into coaxial alignment with the open lower mouth of said locking ring proximate to the said open upper mouth of said cup and when said locking ring and cup are moved axially into engagement, the said locking shoulders engage and ride past one another by radial deformation of at least one of said locking shoulders followed by restoration to normal contour thereof to thereby mechanically interlock said shoulders, the diameter of the open lower mouth of said locking ring being dimensioned to lie in the conical surface of the conical wall of said cup when said cup and locking ring are interlocked as aforesaid, the said flanges of said locking ring and cup being thereby disposed in parallel planes and spaced apart a distance not greater than the thickness of the pallet platform at the periphery of the foot-receiving openings aforesaid.
2. A nestable molded plastic two-part foot of claim 1 wherein the bottom wall of the cup is provided with at least one opening, said opening, said opening being adapted to receive fastening means for retaining an auxiliary runner on the bottom wall of the cup.
3. A nestable molded plastic two-part foot of claim 1 wherein the lower face of the flange of the locking ring and the upper face of the flange of the cup are provided with protrusion adapted to grip-contacting portions of a pallet platform immediately adjacent a foot-locating opening 4. A nestable molded plastic two-part foot of claim 1 wherein the outer surface of the conical wall of the locking ring is provided with a stop shoulder positioned at a predetermined distance from the said locking shoulder toward the upper open mouth of the locking ring, said stop shoulder being adapted to abut the upper face of the cup flange and to position the flange of the locking ring at a predetennined distance thereabove not greater than the thickness of the pallet platform at the periphery of the foot locating opening aforesaid.