CA2209245A1 - Paperboard pallet system - Google Patents

Abstract

Disclosed is a superior strength pallet system (10, 11, 12, 13), having particular advantages over corrugated pallets of prior art, yet providing the same advantages of lighter weight and less cost than that of wooden pallets.
Due to the design flexibility in accommodating as many interior components (11, 12, 13, 14) as is necessary to support a stable load, the strength of this pallet is virtually unlimited within its peer grouping of corrugated pallets.

Description

CA 0220924~ l997-07-02 W O97/16354 PCT~US96n7455 PAPERBOARD PALLET SYSTEM

BACKGROUND OF THE INVENTION

While serving distribution channels for many years, conventional wool~en pallets have come under displacement pressures from corrugated pallets. The growing popularity of corrugated pallets can be linked in part to the inherent drawbacks of wooden pallets which 5 include but are not limited to, safety considerations (splinters, weight, and ~roken boards), contamination concerns in food processing plants, disposal costs, and space requirements for storage.
The proliferation of paperboard pallets is the result of many atternpts to overcome one or several of the wooden pallet drawbacks.
10 By categorizing the evolution of paperboard designs it becomes evident that no one design has yet been developed which satisfies the requirements of multiple distribution channels, thereby possessing mass appeal. I~ is safe to say that virtually all of the paperboard palle:s are relatively lightweight, maintenance free, can be recycled in 15 an e,~isting recycling infrastructure which is characterized with a residual value for the reclaimed material, can be transported and stored unassembled for maximum freight utilization, and assembled on-site for loading.
The most significant characteristic is featured in those designs 20 whic~ have a method or apparatus which provides for automatic assembly. This characteristic in and of itself establishes commercial viability. Because of the rising cost of transportation and labor, a comrnercially viable design must, (1) provide for efficient transportation of the material to the end user or be physically located 25 close to the end user; and (2) minimize, if not totally eliminate, the need to fabricate the pallet manually, which has a greater impact on cost than the transportation consideration. Virtually all patented CA 0220924~ l997-07-02 W 097/16354 PCT~US96/17455 paperboard pallet designs from U.S. Pat. No. 3,131,656 and prior are manually assembled designs. By virtue of this fact aione, these = designs are rendered commercially enviable and thus, obsolete.
The remaining pallet designs, while possessing various degrees 5 of automation potential, are limited in the scope of their end use application. A group of these remaining pallets are illustrated by the designs shown in U.S. Pat. Nos. 4,714,026; 3,434,434 and . 4,319,530. Such pallets are limited to light weight end uses due to the weak lateral rigidity.
- - 10 A more recent grouping of pallets, illustrated by U.S. Pat. Nos.
4,979,446; 5,218,913; 5,184,558; and 4,792,325 are constructed - from a single, scored and folder sheet of corrugated. This type of design significantly limits the range of application. Such pallets were - designed to be either very strong for heavy weight applications, as in '446, or for medium to light weight applications, as in '5E;8. The only - differentiating component of the pallet is in the weight of the combined materials. Attempting to increase the strength, or reduce the cost of any one of these pallets, can only be accomplished by - changing the basis weight of the paper materials used in the - -- 20 construction. However, any attempt at reducing the amount of board square footage utilized in the design would in fact change the patented design of the pallet. This, in essence, pigeon holes these designs to a specific market end use segment.
- Many of the automated pallet designs of the prior art require extensive and continuous folding and gluing. There are at least three ~- undesirable attributes to this fabrication method; (1) the space required to accommodate the machinery; (2) the manufacturing speed ~ of ~the equipment is limited due to the variances in the corrugated sheet and the requirement for the corrugated sheet to be contorted so - 30 that it folds back upon itself several times through the process; and (3) the high maintenance cost and associated down time of = preventing, and correcting, machine failures: i.e., blocked glue heads, , CA 0220924~ 1997-07-02 W O 97~16354 PCT~US96/17455 jan~med sheets of corrugated, cracked or ripped sheets through the folcling process.
No known self-supporting paperboard pallet structure makes adequate accommodation for wet environments. Due to the fact that 5 mo,t pallets engineered for automation utilize one sheet of corrugated, adding a barrier coating to combat moisture would result in not being able to glue the sheet into its final form. In fact this is a significant limiting attribute. Paperboard pallets exposed to even surface moisture on the shipping platform will begin to realize accelerated 10 str~ngth loss.
There is clearly a need and a market demand for a pallet constructed of sheet material, such as corrugated paperboard and the like. that assembles efficiently, meets a broad range of customer expectations for strength, stability and ease of use, and that is easily 1 5 disposable or recyclable.

SUMMARY OF THE INVENTION

The primary objectives of the present invention are (1) to 20 provide a paperboard pallet that is represented with a higher supl~orting strength to pound of paper utilized ratio; and (2) to provide a pallet design that serves the mass market requirements, from light to heavy weight applications.
Further, while keeping the primary objectives in mind, this 25 design was held to a requirement that insures cost efficient fabrication em,r,loying manufacturing operations that favor a high volume mix of busi ness.
It is also an object of the present invention to provide a pallet con~truction that is suitable for use in specialty applications such as 30 for display purposes, e.g., in a retail store environments.
It is an additional object to provide a pallet design which minimizes the number of components used to construct the pallet, but CA 0220924~ 1997-07-02 W O 97/16354 PCT~US96/17455 places no restrictions on the amount of fiber board utilized to meet the ~- strength requirements of the end use application.
In another aspect, the present invention provides a pallet for storing and transporting material thereon comprising of stringers and 5 cross members that are manufactured to an end use specification.
The stringers and runners are comprised of iaminated corrugated, and the like; die cut sheets which are sheathed in an outer corrugated die cut sheet that is capable of featuring a moisture barrier coating. The number of laminated die cut sheets is a direct function of the strength 10 requirements for the end user. Further, the number of stringers and cross members is aiso a function of the end use strength = requirements.
- In a further aspect, the present invention provides a pallet for storing and transporting material thereon comprising of interlocking 15 cross members and stringers that can be formed to create two versions of a finished pallet. One form is characterized by a flush - edge around the perimeter of the pallet. In this way, the pallet is compatible with automated racking systems which are found in many of the high volume distribution warehouses. Further, this flush edge 20 version compliments the stacking requirements of corrugated shipping containers which require a flat and solid stacking platform under the corners of said container for maximum strength utilization.
The other version employs an interlocking means of final assembly by hand. In this way, end users can take advantage of :
25 transportation cost as well as down time from their current labor ~- situation.
The stringers and cross members for both of these pallet ~; versions are also capable of featuring cut outs for fork tine entry in two or four way configuration. These cut outs also provide additional 30 stability by utilizing the cut out portion, in hinged fashion, to create a buffer to the underside of the fork tine channel. This buffer assist in preventing tearing of the individual components from the pressure , CA 0220924~ 1997-07-02 W O 97/16354 PCT~US961174~5 exerted by the fork tines.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention have been chosen for purposes of illuslration and description, and are shown in the accompanying drawings wherein;
Fig. 1 is a perspective view, partially cut away, of a corrugated pallet in accordance with the present invention. This version features the ~lush edge design which requires automated assembly.
Fig. 2 is an enlarged fragmentary perspective view of a base member (stringer) and a deck member (cross member) of Fig. 1, shov/ing their manner of locking for the Flush Edge design.
Fig. 3 is an enlarged fragmentary perspective view showing the 1~ comi~onents which make up a base member (stringer). It is important to ncte that the cross members are fabricated on the same piece of machlinery in the identical fashion.
Fig. 4 is an enlarged fragmentary perspective view showing three modifications of the base member for various end use applications. Shown on a continuum, the components requiring great_r strength are specified with additional interior components.
Fig. 5 is a front plan view of an interior blank, by itself or when laminated to a like interior biank is suitable for forming the interior of the b3se member (stringer) of Figs. 1, 2, 3 and 4.
Fig. 6 is a front plan view of the sheath blank suitable for forming the protective covering to the base member (stringer) of Figs.
1 , 2, 3 and 4.
Fig. 7 is a front plan view of the interior blank, by itself or when iamin;3ted to a like interior blank, is suitable for forming the interior of the cross member of Figs. 1 and 2. This particular schematic features access holes for fork tine entry.
Fig. 8 is a front plan view of the sheath blank suitable for CA 0220924~ 1997-07-02 -. W O 97/163~4 PCT~US96/17455 .

forming the protective covering to the cross-member of Figs. 1 and 2.
Fig. 9 is a perspective view, partially cut away, of a corrugated pallet in accordance with the present invention. This version features the interlocking design which accommodates manual assembly.
Fig. 10 is an enlarged fragmentary perspective view of a base member (stringer) and a deck member (cross-member) of Fig. 9, showing their manner of interlocking.
Fig. 11 is a perspective view showing the underside of the fork tine cut outs which feature a buffer pad.
DESCRIPTION OF THE PREFERRED EMBODIMENTS

Fig. 1 shows an embodiment 10 of a pallet in accordance with the present invention which comprises a plurality of elongated base - 15 member or stringers 11 laid in parallel, spaced positions longitudinally of the pallet 10 and perpendicularly interconnected to form a free standing weight supporting lattice structure by a plurality of elongated - deck members or cross members 12, laid in parallel, spaced positions - laterally of the paliet 10 to respectively perpendicularly intersect the members 11 at axially displaced positions there along. The pallet 10 ~ is not limited to any specific number of base members and deck - members but is designed to be customized to meet the specific weight distribution requirements of the end user.
This Flush Edge version of joining the cross members and stringers is used within distribution environments that require a smooth edge so that the pallet is not hung up on automated conveyor . .
systems. Additionally, this version is specified for those applications which demand structural support on the extreme corners.
- A sheet or deck 13 (shown in cutaway) is applied to the top and four sides to cover the interstices of the underlying lattice framework as well as to lock in the exterior intersections 15 of the stringers and cross members. The stringers 11 and the cross =

CA 0220924~ 1997-07-02 W O 97/16354 PCTnUS96/17455 meml)ers 12 are each provided with aligned cutouts 14 to provide longitudinal channels between the floor and the pallet structure 10 for four-way access there into for pallet lifting purposes by the tines of a fork lift or a similar material handling apparatus. These cutouts can be 5 cust~mized to limit the access to two-way, restricting the entry to the front and rear.
The sheet or deck member 13, and members 1 1 and 12 are all constructed of corrugated paperboard, plastic, or similar material.
Figs. 2 through 8 show members 1 1 and 12 having individually 10 lamin~ted components making up a solid core with their corrugation directions running vertically and an outer sheath of the same material which creates a moisture barrier along the bottom surface and which provides additional thickness and support.
The members, 1 1 and 12 are interconnected at their points of 15 intersection. This interconnection can be accomplished one of two ways First, as shown in Fig. 9, and again in close up separated form in Fig. 10, the locking and linking of the interstices, in which a void of one member mates in close tolerance relationship with a comp ementary void of and intersecting member. The joints should 20 impar~ sufficient rigidity to the intersection to maintain a fixed relatic nship. Shown again in close up fragmentary view in Fig. 9 with all interstices employing this method of interconnecting the stringers to the deck members. Members 11 are provided with upwardly facing "U" shaped rectangular notches 17 having spaced vertical walls 25 ascending from opposite edges of an interior horizontal wall.
Memters 12 are provided with similar downwardly facing "U" shaped notch3s 18. The notches 17 and 18 are oriented perpendicularly to the elongation of the respective members 11 and 12, with the width (distance between opposite walls) of notches 17 being slightly less 30 than the width (dimension perpendicular to the elongation) of the opposing member 12, and the width of notches 18 being slightly less than tne width of the opposing member 11. The vertical dimensions CA 0220924~ 1997-07-02 W O97tl6354 PCT~US96/17455 of the longitudinal members 11 and lateral members 12 are made equal, and the sum of the depths of the notches 17 and 18 is equal to - the vertical dimension of each member 11 and 12.
-- This type of interconnecting and locking design is used for all ~= 5 interstices, as stated earlier. It also facilitates manual assemble of the fabricated components at the location of the end user. It is also possible to eliminate the deck sheet 13 if the lattice structure and the packaging configuration (usually boxes) of the material being shipped are compatible. The primary drawback of this design is the void that is created at the exterior perimeter of the pallet. The void that is created, particularly at the extreme corners of the pallet dramatically reduces the compression strength of a corrugated shipping container that is positioned over it. Empirically, is has been proven that a corrugated container that overhangs a pallet can lose up to thirty percent (30%) of its compression strength.
To overcome the limiting attributes of the aforementioned interconnecting design, alterations to the design have been made to -- the extreme ends of the stringers and cross members to create a- continuous, flush perimeter of the pallet. As shown in Fig. 2, this has the greatest impact on the extreme exterior corners 16 of the pallet.
The stringers 11 have underlapping extensions 19, which mate with - the overlapping extensions 20, of the cross members.
Similarly, the extensions, 19 and 20 combine in equal halves to make up the height of the pallet. Fig. 1 shows that within the ~ 25 corners, the identical "U" shaped configuration 17 is employed on the ~- stringers which mate with the overlapping extension 20 of the cross members. Likewise, as shown in Fig. 1 along the base member, the - "U" shaped configuration 18 which mates with the underlapping extension 19 of the stringer. The length of the extensions 19 and 20 is in direct relationship to the thickness of its interconnecting mate to create a flush and full overlapping joint. The use of a deck sheet 13 with full overlapping edge flaps 21 is required to secure the perimeter . . .

CA 0220924~ 1997-07-02 W O 97/16354 PCT~US96/174 for lhis interconnecting design.
As the skilled artisan will appreciate, there is a basic structure that is characteristic in each of the aforementioned pallet conligurations. Both, stringer and deck member, sre made up of two 5 basic components. Shown in Fig. 3 in separated form, is an interior component 22 for the stringer and 24 for the cross member, which is a die cut component with vertical corrugation direction for maximum compression strength. An exterior sheath 23 for the stringer and 25 for the cross member, also die cut, encases the interior component(s) 10 Z2 a nd 24 on three sides, across the bottom and extending vertically on koth sides. The function of the sheath is to create a moisture barr er to the undersurface of the interior components 22 and 24.
This undersurface also happens to be the contact surface to the shipJing pl~tform. As sh~wrl Ir, Fig. 4, the r.umber o, inierior 15 components is commensurate with the strength requirements of the pallet. An "end use continuum" reflects the possible construction of the l~allet stringer and/or cross members for heavy, medium and light weight applications.
Fig. 5 shows a profile view of the interior component to the 20 stringer 22. This individual component is not restricted to a specified construction i.e., single, double or triple wall. While shown as a component for the 'Flush Edge' design, this component is commonly employed in both Flush Edge and Interlocking designs and can be modified as desired to satisfy each design. Additionally, this drawing 2~ is not shown with fork tine cutouts, but it can readily be modified to crea~e a pallet with four way fork tine entry. This interior component _ 22 is laminated to like components to build a structure that is strong str~cturally to meet the end use specifications. Depending upon the thickness, or number of components employed, an outer sheath 23, 30 as shown in Fig. 6 in front plain view, is used to encase the interior components. If specified, the sheath 23 can be manufactured with a moisture barrier coating such as wax or a Michelman coating. The .
- CA 0220924~ 1997-07-02 W O 97/16354 PCT~US96/17455 - size of the interior panel 26, is in direct proportion to the total thickness of the laminated interior pieces 22.
Fig. 7 shows a profile view of the interior component to the cross member 24. This individual component is not restricted to a ~ 5 specified construction i.e., single, double or triple wall. While shown as a component for the Flush Edge design, this component is employed in both Flush Edge and Interlocking designs and can be modified to satisfy each design. This interior component 24 is laminated to like components to build a structure that is strong structurally to meet the end use specifications. Depending upon the thickness, and/or the number of components employed, an outer sheath 25, as shown in Fig. 8 shown in front plain view, may be used to encase the interior components. If specified, the sheath 2~ can be manufactured with a moisture barrier coating such as wax or a Michelman coating. The size of the interior panel 26, is in direct - proportion to the total thickness of the laminated interior pieces 24.
Each fork tine cut out features a buffer pad 27, shown in Fig. 8 in front plain view and again in perspective view of the underside of - the cut out in Fig. 11. This feature can be incorporated into all fork tine openings. The buffers 27, are hinged along the top edge of the opening 28, and extend downward at a length from the platform _ r surface that is specified by the end user. The Buffer Pad extends on each side of the fork tine opening, and as such, there is no restriction to a left of right handed piece thereby simplifying final assembly.
, 25 In accordance with the invention, a superior strength pallet has been described by reference to preferred embodiments thereof, having particular advantages over corrugated pallets of prior art, yet providing the same advantages of lighter weight and less cost than that of - wooden pallets. Due to the design flexibility in accommodating as many interior components as is necessary to support a stable load, the - strength of this pallet is virtually unlimited within its peer grouping of corrugated pallets.

-- =
CA 0220924~ 1997-07-02 The design of the pallet provides for more supporting members to contact either the floor or the top of an underlying pallet load. This ensu~res greater weight distribution and, for stacked pallets, signlficantly reduces crushing or creasing of the load (in most 5 instances boxes) of underlying pallets. Because the base and deck merr bers support the load through contact with the floor in both the long tudinal and lateral members, the pallet in accordance with the invention can traverse most roller conveyor systems in any direction.
Mos-~ prior art pallets which have only longitudinal floor support are 10 limited to movement in only one direction since the rollers must generally be oriented perpendicularly to the main supporting member in order to roll the pallet.
The pallet design provides for the ability of the pallet to absorb and ~Nithstand motion shock in all directions. By providing for 15 interlocking members and having all supporting members contacting the f oor, this pallet will not collapse because of side motion pressure.
Most prior art pallets do not have this ability and are subject to failure when used to transport loads by truck or rail over long distances.
Those skilled in the art to which the invention relates will 20 appreciate that the foregoing detailed embodiments serve merely to illustlate exemplary implementations of the invention and that various subs1itutions and modifications may be made to the same, without departing form the spirit and scope of the present invention as defined by the claims appended hereto.

Claims (19)

CLAIMS:

1. A corrugated pallet comprising the following features:
(a) a flush edge, formed by automated assembly;
(b) a plurality of base or stringer members; and (c) a plurality of deck or cross members, locked with said base or stringer members;
wherein the cross members and stringer members are fabricated in an essentially identical manner; and wherein the strength of the cross members and stringer members is predetermined based upon the desired end use application of the pallet.

2. The pallet of Claim 1, wherein each of the base or stringer members are formed from one or more laminated corrugated interior blanks.

3. The pallet of Claim 1, further comprising a sheath blank which provides a protective covering to the base or stringer members.

4. The pallet of Claim 1, wherein each of the deck or cross members is formed from one or more laminated corrugated interior blanks.

5. The pallet of Claim 4, wherein the deck or cross members further include access holes for fork tine entry.

6. A corrugated pallet-comprising the following features:
(a) interlocking design formed by manual assembly;
(b) a plurality of base or stringer members; and (c) a plurality of deck or cross members, locked with said base or stringer members;
wherein the cross members and stringer members are fabricated in an essentially identical manner; and wherein the strength of the cross members and stringer members is predetermined based upon the desired end use application of the pallet.

7. The pallet of Claim 6, wherein each of the base or stringer members are formed from one or more laminated corrugated interior blanks.

8. The pallet of Claim 6, further comprising a sheath blank which provides a protective covering to the base or stringer members.

9. The pallet of Claim 6, wherein each of the deck or cross members is formed from one or more laminated corrugated interior blanks.

10. The pallet of Claim 9, wherein the deck or cross members further include access holes for fork tine entry.

11. A pallet comprising a plurality of stringers and cross members that are manufactured from laminated corrugated die cut sheets, said sheets being sheathed in an outer corrugated die cut sheet, and wherein the number of laminated die cut sheets is a predetermined function of the end use strength requirements, and wherein the number of stringers and cross members is also predetermined based upon end use strength requirements.

12. The pallet of claim 11, further comprising interlocking cross members and stringers and a flush edge around the perimeter of the ballet.

13. The pallet of claim 11, further comprising an interlocking means for final assembly by hand.

14. The pallet of claim 12 or 13, wherein the stringer members and the cross members further include two or more hinged cut out segments which, when hinged, form a buffer to the underside of a fork lift tine.

15. The pallet of claim 11, wherein the stringer and cross members support a load on the pallet through contact with the floor in both the longitudinal and lateral direction.

16. The pallet of claim 15, having sufficient longitudinal and lateral support to enable it to traverse most roller conveyor systems in any direction.

17. The pallet of claim 1 1, having sufficient longitudinal and lateral support to enable it to absorb and withstand motion shock in all directions.

18. The pallet of claim 11, further comprising interlocking stringer and cross members, and wherein all of said interlocking members are extend to the base of said pallet, for contact with the floor.

19. The pallet of claim 11, having sufficient longitudinal and lateral support to enable it to not collapse because of side motion pressure.