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(11) | EP 0 134 659 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Paperboard pallet |
| (57) A paperboard pallet has a sheet (A) of cardboard forming a pallet platform (12) supported
above the floor by a plurality of skid runners (B). The skid runners (B) each comprise
a continuous U-shaped channel member with a pair of outwardly extending flange portions
(34, 36) which have an open top channel in which supporting cores (40) are received,
the cores (40) mating flush with the bottom of the platform (12). The flange portions
(34, 36) having tacking surfaces which are attached to the bottom of the pallet platform
(12). The tacking surfaces extend the length of the channel members and provide spaced
apart tacking surfaces, staples may also be inserted, which resist twisting of the
skid runners (B) relative to the pallet platform (12) in the yaw, roll and pitch direction.
In particular, the unitizing, tacking surfaces resist twisting in the yaw direction
to prevent destruction of the pallet should the runner (B) be struck by a fork of
a lift truck. Score lines (14, 16) are formed in the pallet platform to form unitizing flaps (18, 20) which fold up to meet the stacked material and by means of wrapping facilitate the provision of a unitary package. The skid runner (B) terminate short of the score lines (14, 16) to facilitate nesting of two palletized packages one on top of the other. |
[0001] The invention relates to a pallet on which material can be supported for storage and handling. Pallets are normally shifted using forklifts and for this purpose are provided with skid runners which support a pallet platform above floor level in such a manner that forks of the forklift may be inserted underneath the pallet platform.
[0002] Typically, wood pallets have been utilized in the material handling industry owing to the structural needs of such platforms in handling heavy loads and their shifting weights. The forces and loads imposed upon the pallet by the forklift have also made a heavy wood construction highly desirable. However, wood pallets are becoming increasingly expensive and also are heavy which means that extra freight must be paid for when shipping material on these pallets by air, rail, road, or water.
[0003] Heretofore, various cardboard pallets have been proposed which are mainly disposable. When the loaded pallet shipment reaches its destination, and the material stacked on the pallet is unloaded, the pallet may be disposed of. Thus, the return freightage of the pallet or disposition of an otherwise expensive wood pallet is eliminated.
[0004] However, the problem that occurs with cardboard pallets is that these pallets must of necessity support heavy loads of stacked material. The loaded pallets are typically stacked on top of each other in warehouses. Thus, if any of the structural features of the cardboard pallet fail, the resulting palletized material package may be unhandeable from the standpoint of being conveniently maneouvered with a forklift.
[0005] In United States Patent No. 3,891,429 a cardboard pallet is disclosed having a specially designed runner in which a plurality of cylindrical cores are aligned in a row for supporting tthe pallet. Top flaps of the runner are folded down and adhered together. The exposed top flap is then glued to the bottom of the pallet platform. This is the sole connection between the runner and the platform. However, the double-folded flaps cause an uneven runner surface to be adhered to the bottom of the platform and there is not enough surface area adhered to the platform to accommodate a heavy load and shifting of the weight about the skid runners in a stable manner. Any twisting of the runner relative to the platform in the yaw direction will cause the runner to come unglued. In the event that the forks of a forklift truck strike the skid runner, the runner will be easily knocked loose and the skid and the pallet destroyed.
[0006] United States Patent No. 3,601,067 likewise discloses a disposable cardboard pallet having individual legs supporting the pallet above the floor. Each leg includes a cylindrical core acting as a base. While such a pallet provides for entry of the forklift from either side, the individual legs are particularly susceptible to bumping by the forks of a truck and destruction of the pallet as each individual leg must take the full impact of the pallet as well as shifting forces of the load of material thereon.
[0007] United States Patent No. 2,611,569 discloses a cardboard pallet having continuous skid runners. Here again, the skid runner has a rectangular box section with a top wall which is glued to the bottom platform surface. Staples may also be utilized for securing the platform and skid runner. However, the same problem exists of having too little tack surface for gluing the runner to the skid platform. Not only is the tack surface insufficient, but it is concentrated in a narrow strip which is unlikely to be able to resist twisting in the yaw direction should a fork of the lift truck strike the skid runner. The same is true of twisting moments about the roll and pitch axes between the skid runner and the pallet platform as the loads imposed upon the platform by the stacked material shift during handling.
[0008] It is among the objects of the invention to provide a paperboard pallet construction in which a pallet platform and skid runners supporting the platform above floor level are joined together in a unitary construction.
[0009] According to the invention there is provided a paperboard pallet on which material can be stacked for handling and which may be transported by
a forklift comprising
a member forming a pallet platform;
a plurality of continuous elongate skid runners carried across a bottom of the pallet platform, supporting and elevating the platform above the floor and spaced apart sufficiently to permit forks of a forklift to be inserted therebetween underneath the platform with each said skid runner including an elongate channel member having a pair of spaced vertical side portions vertically dimensioned to provide said elevation and a base portion bridging the vertical sides defining a generally U-shaped open top channel; and
a plurality of tubular cores carried in each channel and having a cross-sectional width dimension generally equal to the width of the base portion;
characterised by load-bearing unitizing flange means integrally attached to upper edges of the vertical sides portions and extending in opposing directions leaving the channel open and exposed to the bottom of said pallet platform permitting attachment of the cores thereto, the cores having a top surface in load bearing contact with the bottom of the pallet platform and a bottom surface attached to the base portion of the runner, the unitizing flange means having upper tacking surfaces facing and mating with the bottom of the pallet platform and the unitizing load-bearing flange means extending on opposing sides of the open top of the channel lying generally coplanar with the top surfaces of the cores against the platform bottom; means securing the tacking surfaces of the unitizing flange means to the bottom surface of the pallet platform;
the unitizing load-bearing flange means being spaced apart a distance corresponding generally to the width of the channel providing attachment to the bottom surface of the pallet platform over a surface area outside of a projection of the surface area of the base portion of the channel member providing increased resistance to twisting moments of the skid runners relative to the platform; and
the top surfaces of the cores and the tacking surfaces of the load-bearing flange means providing an increased load-bearing surface securing the pallet platform and skid runners in a unitized manner to resist forces on a loaded pallet due to shifting load and inertia forces.
[0010] Providing the pallet platform, the skid runners supporting the pallet platform, and the material stacked on the platform to be joined together in a unitized configuration makes the palletized package of material a more integral construction having increased structural integrity for accommodating material handling loads.
[0011] The construction can facilitate stacking of loaded pallets on top of each other and can give improved crush strength and resistance to twisting of the paperboard skid runners relative to the paperboard pallet platform.
[0012] The load-bearing flanges of the channel members are spaced from one another over a much greater area than the conventional box formed skid runners to provide increased resistance to twisting moments of the skid runner relative to the platform and to provide a wider surface over which the load is distributed over each skid runner. Not only are the load-bearing flanges attached to the bottom of the pallet platform, but the top perimental surface of each core element is secured between the bottom of the platform and the base of the skid runner for increased structural integrity and load-bearing ability. Thus, the forces acting on the pallet tending to separate the skid runners from the pallet platform during handling of material are greatly reduced to enhance the non-destructibility and reuse of the pallet.
[0013] The material stacked on the pallet platform and made integral therewith by means of the unitizing flaps either polywrapped or strapped together and the increased surface attachment skid runners and cores all provide for a unitized pallet construction in which the material, platform, and skid runners provide a unitary, palletized package which may be moved as a unit with increased structural integrity.
[0014] The invention is diagrammatically illustrated by way of example in the accompanying drawings, in which:-
Figure 1 is a perspective view illustrating a palletized package of stacked material incorporating a paperboard pallet according to the invention;
Figure 2 is a perspective view of a paperboard pallet according to the invention;
Figure 3 is a fragmentary sectional view of a paperboard pallet according to the invention showing a pallet platform and a skid runner having increased attachment and load bearing and moment resisting ability;
Figure 3a is a perspective view of a high crush strength cylindrical core element for use with skid runners in a paperboard pallet according to the invention;
Figure 4 is a bottom plan view of a paperboard pallet according to the invention;
Figure 5 is an end view of the pallet of Figure 4;
Figure 6 is a side view of the paperboard pallet of Figure 4;
Figure 7 is a perspective view of a palletized package incorporating a paperboard pallet according to the invention illustrating the nesting features thereof; and
Figure 8 is a fragmentary plan view showing a core element located in position within a skid runner of a paperboard pallet according to the invention.
[0015] The intention is that a paperboard pallet according to the invention and a palletized package made from the pallet can either be used as a disposable product or is of such structural characteristics that it may be reused. The pallet may be constructed either from pasteboard or corrugated or fluted paperboard.
[0016] Material can be stacked on the pallet and tied thereto by any conventional means for handling of the material and transportation thereof. The pallet is of the kind which is typically handled by a forklift truck and the palletized package can be stacked and stored or transported by a freight transportation system.
[0017] Referring to the drawings, a paperboard pallet generally indicated at 10 comprises a piece of cardboard A which forms a pallet platform 12 and which has a pair of inwardly spaced marginal score lines 14 and 16 which form marginal material unitizing flaps 18 and 20 which can be folded upwardly about the score line 14 and 16 to meet the material stacked on the pallet and provide a unitized package P therewith by means of strapping or wrapping about the material and unitizing flaps, as can be seen in Figure 1.
[0018] While only the two unitizing flaps (18, 20) are shown which extend across the entire side of the cardboard piece A, unitizing flaps may be provided at two other sides 12a also so that there are flaps on all four sides of the platform 12 for unitizing particular kinds of loads.
[0019] Carried by the bottom of the pallet platform 12 are a plurality of skid runners B. Each skid runner B includes a channel member 24 forming a channel 26. The skid runners may be formed from a single piece of cardboard which is scored such that the channel member 24 may be folded and formed as can best be seen in Figure 3.
[0020] Each channel member 24 includes a pair of vertical side portions 28 and 30 which are joined by a base portion 32. The side portions 28 and 30 have a sufficient height to elevate the platform 12 above the floor as desired. The skid runners B are spaced across the bottom of the pallet platform to permit insertion of the forks of the forklift truck therebetween and underneath the platform. Unitizing load-bearing flange means extend from each vertical side outwardly away from the channel 26. The load-bearing flange means includes a first horizontal flange 34 extending from the side portion 30 and a second horizontal flange 36 extending from the side portion 28. The flange means unitize the skid runners B and pallet platform 12 and extend continuously along the length of each skid runner B. Fluting 37 extends in the direction shown for increased vertical stiffness in the sidewalls.
[0021] Perforated sections 38 are provided in the side walls of the channel members 24 which can be punctured by the forks of a forklift truck. This makes the pallet a four-way pallet so that the pallet may be engaged by the forklift from any of its four sides.
[0022] A plurality of high crush strength fibre or cardboard cores 40 are disposed in a row inside the channel 26 of each skid runner B. The cylindrical tubular cores 4 may be spiral or convulute wound fibre tubes for example with a crush strength of 800 kilos. As many cores 40 may be utilized as is necessary to meet the load requirements.
[0023] The flange portions 34 and 36 extend away from the U-shaped channel 26 to leave the top of each channel member 24 open and exposed to the bottom of the pallet platform 12. The cores 40 extend from the base portion 32 of the channel member 24 to the underneath side of the pallet platform 12 and are adhesively secured both to the base portion 32 and to the pallet platform 12.
[0024] The flange portions 34 and 36 lie generally coplanar with a top surface 42 of each of the cores 40 such that tacking surfaces 34a and 36a of the flange portions and the top surface 42 of the core element lie generally coplanar for attachment of the flange portions to the underneath side 13 of the pallet platform 12.
[0025] As can be seen in Figure 8, the tacking surfaces 34a and 36a of the unitizing flange portions and the top surface 42 of the core elements 40 produce a much wider attachment surface against the bottom of the pallet platform. Particularly, the tacking surfaces 36a and 34a being spaced considerably apart, a larger moment arm is produced for resisting twisting of the skid runner B in a yaw direction relative to the pallet platform 12.
[0026] This also produces increased resistance against twisting in the roll direction of the skid runner B and pallet platform 12 as well as in the pitch direction. The continuous attachment of the tacking surfaces 34a and 36a along the entire length of the skid runner to the underneath side 13 of the pallet platform 12 make twisting of the skid runner in the yaw direction relative to the platform highly unlikely so as to render the pallet less destructible with respect to the bumping of the pallet by the forks of a lift truck.
[0027] The ends of the skid runners B terminate short of the unitizing flaps A and short of the score lines 14 and 16 to facilitate stacking of the skid runners. As can be seen in Figure 7, a top of the stacked material typically includes a 90 degree corner board 46 at each of two sides, each corner board 46 having a vertical leg 48 and a horizontal leg 50. The corner boards 46 are typically made from paperboard and fit over an edge of the stack of the material which receives strapping 52 so as to prevent damge to the material. In this case, the skid runners B of a superposed palleted package are designed to nest and fit between the horizontal legs 50 of the corner boards 46 in an interlocking manner. This provides for more stability ih the stacking configuration of the palletized packages. The strapping 52 is wrapped around the unitizing flaps 20, 18 and the corner boards 46. In the palletized package P illustrated in Figure 1, a polywrap material is wrapped about the pallet platform underneath the sides thereof and over the corner boards 46 which is heat shrunk making an integral palletized package. In this application, the unitizing flaps 18 and 20 of the piece of cardboard A are particularly advantageous in securing the polywrap and pallet together. the polywrap material may be any suitable stretch film which is generally of 4 to 8 mil thickness either blown or extruded such as LFX 90-20 stretch film manufactured by the Linear Film Co.
a member (A) forming a pallet platform (12);
a plurality of continuous elongate skid runners (B) carried across a bottom of the pallet platform, supporting and elevating the platform above the floor and spaced apart sufficiently to permit forks of a forklift to be inserted therebetween underneath the platform with each said skid runner (B) including an elongate channel member (24) having a pair of spaced vertical side portions (28, 30) vertically dimensioned to provide said elevation and a base portion (32) bridging the vertical sides defining a generally U-shaped open top channel (26); and
a plurality of tubular cores (40) carried in each channel (26) and having a cross-sectional width dimension generally equal to the width of the base portion (32);
characterised by load-bearing unitizing flange means (34, 36) integrally attached to upper edges of the vertical sides portions (28, 30) and extending in opposing directions leaving the channel (26) open and exposed to the bottom (13) of said pallet platform (12) permitting attachment of the cores (40) thereto, the cores (40) having a top surface (42) in load bearing contact with the bottom (13) of the pallet platform (12) and a bottom surface attached to the base portion (32) of the runner (B), the unitizing flange means (34, 36) having upper tacking surfaces (34a, 36a) facing and mating with the bottom (13) of the pallet platform (12) and the unitizing load-bearing flange means extending on opposing sides of the open top of the channel (26) lying generally coplanar with the top surfaces (42) of the cores (40) against the platform bottom (13); means securing the tacking surfaces (34a, 36a) of the unitizing flange means (34, 36) to the bottom surface (13) of the pallet platform (12);
the unitizing load-bearing flange means (34, 36) being spaced apart a distance corresponding generally to the width of the channel (26) providing attachment to the bottom surface (13) of the pallet platform (12) over a surface area outside of a projection of the surface area of the base portion (32) of the channel member (24) providing increased resistance to twisting moments of the skid runners (B) relative to the platform (12); and the top surfaces of the cores (40) and the tacking surfaces (34a, 36a) of the load-bearing flange means (34a, 36a) providing an increased load-bearing surface securing the pallet platform (12) and skid runners (B) in a unitized manner to resist forces on a loaded pallet due to shifting load and inertia forces.
a pallet platform (12) including a single rectangular piece of paperboard (A) having four sides and a plurality of skid runners (B) carried by a bottom surface (13) of the pallet platform (12) supporting the platform above the floor with the skid runners (B) being spaced sufficiently from one another to permit forks of a forklift to be inserted therebetween;
characterised by a first pair of parallel scores (14, 16) spaced inwardly from two opposing sides of said piece of paperboard (A) forming marginal unitizing flaps (18, 20) along substantially the entire length of said sides; the marginal flaps (18, 20) being foldable to a vertical position about the score line (18, 20) to meet the material stacked on the pallet across substantially the entire width of the stacked material and unitize the material with the pallet when the wrapping means is wrapped thereabout.
a generally rectangular section (A) of paperboard having four sides providing
a pallet platform (12);
a plurality of elongated skid runners (B) carried by a bottom (13) of the pallet platform (12) extending continuously and substantially from one side to an opposing side;
the skid runners (B) each including a continuous paperboard channel member (24) having an open interior channel (26);
a plurality of cores (40) disposed in a row within the channels (26); characterised in that the skid runners (B) terminate short of the sides to create a nesting space so that the skid runners (B) fit between horizontal flanges (50) of the corner boards (46) when fitted on opposing sides of the top of the stack to permit nesting of the skid runners (B) within the corner boards (46) of a stacked pallet therebelow.