Nest type pallet improved racking and conveyor performance

Abstract

To provide a pallet, particularly a nest type pallet with improved racking, stacking and conveyor performance.SOLUTION: A nest type pallet (100) has a deck (102) for supporting a load and a set of tapered hollow leg parts (106), the hollow leg part has an upper opening and an inwardly tapered inner surface (108) for receiving a part of a corresponding leg part of another pallet when a plurality of similar pallets are stacked, a part of the hollow leg part has a peripheral support configuration including a lower leg part extension part (110) that projects horizontally from an inwardly tapered part of the hollow leg part toward an edge part of the pallet, and an upper leg part opening (114) for receiving the lower leg part extension part of another pallet when the plurality of similar pallets are stacked.SELECTED DRAWING: Figure 3A

Description

[Technical field]

[0001] The present invention relates to pallets, and more particularly to nestable pallets for improved racking, stacking and conveyor performance.

[0002] A conventional pallet is usually made of wood and has a load-supporting base (1000) that contacts the ground and runways (1002), as illustrated in Figure 1. The runways extend to the ends of the pallet.

[0003] Pallets (1004) (FIG. 2A) are known to be made primarily of polymeric materials and offer many advantages, including being sturdy and reusable. Pallets are sometimes implemented with tapered hollow leg structures (1006) to allow for compact nesting with other similar pallets for compact return shipment. The inward taper required to allow for nesting, and the placement of the legs inside the perimeter of the deck, results in the underside of the legs being significantly set back from the edge of the pallet deck, as shown at d in FIG. 2A.

[0004] Nesting pallets are increasingly being used because they occupy a much smaller volume when stacked empty. Typically, a stack of nested pallets can accommodate roughly three times as many pallets in the same volume as a conventional (bottom deck) pallet of the same external dimensions. However, nesting pallets have a number of limitations and weaknesses due to their shape. To be nestable, the legs of nesting pallets need to have a draft that allows them to nest inside each other and to easily separate from each other when nested inside each other. This means that the pallet legs at the bottom (the part that touches the floor or supporting surface) do not reach the external dimensions of the pallet's top deck, but slope inwards. Typically, for a pallet that is 120 cm long, the bottom legs will be set in from the pallet's perimeter by a "d" of at least 4 cm on each side, but typically more.

[0005] This position of the legs set in from the edge of the pallet limits the functionality of the pallet in several ways. Firstly, as illustrated diagrammatically in FIG. 2B, there is less margin of safety when racked between two beams in storage. The outer distance between the legs of a conventional (e.g. wooden) pallet is the full length of the pallet, which is 120 cm for a 120 cm x 100 cm pallet. The outer dimension of the legs at the bottom of a nesting pallet is typically 120 cm - 8 cm = 112 cm or less. The outer dimension between the beams of the racking system is fixed and is usually around 110 cm. This means that a conventional pallet has a higher margin of safety when placed on this rack compared to a nesting pallet. FIG. 2B shows a nesting pallet placed on the beams of the rack in the "correct" position (solid lines) and in the "incorrect" position (dashed lines).

[0006] A further limitation of conventional nesting pallets, as illustrated in Figure 2C, relates to the inability to "double stack" a nesting pallet on top of an open crate. As can be seen in this schematic, the outer legs of the pallet do not reach the walls of the crate below, resulting in the upper pallet becoming unstable and / or compressing the crate contents.

[0007] A further problem relates to use on conveyors. Nested pallets have a high risk of rolling when transported on a conveyor (roll or chain) because the alignment of the pallet on the conveyor is achieved by guiding devices at the sides of the conveyor, i.e. at foot level. With nested pallets, the width of the feet at any location below the bottom or top deck is less than the full width of the pallet at the top deck. This can lead to the pallet rolling and getting caught on objects etc., as illustrated in Figure 2D. Summary of the Invention

[0008] The present invention is a nestable pallet that provides improved racking and conveyor performance.

[0009] In accordance with the teachings of one embodiment of the present invention, there is provided a nestable pallet for supporting a load on a floor comprising: (a) a deck having an upper surface for supporting a load and having an outer periphery; and (b) a set of hollow legs rigidly integrated with the deck and extending downwardly therefrom to support the deck on the floor, each of the hollow legs having an upper opening and an inwardly tapering inner surface for receiving a portion of a corresponding leg of another pallet when multiple similar pallets are stacked, each of the multiple hollow legs adjacent the outer periphery including a peripheral support arrangement comprising: (i) a lower leg extension that projects horizontally from the inwardly tapering portion of the leg toward an edge of the pallet that corresponds to a donwards projection of the outer periphery; and (ii) an upper leg opening for receiving a lower leg extension of another pallet when multiple similar pallets are stacked.

[0010] According to a further feature of an embodiment of the invention, the lower leg extension forms part of a closed lower portion of the leg.

[0011] According to a further feature of an embodiment of the invention, the inwardly tapered portions of the legs have a taper angle of at least 3 degrees and the lower leg extension has a draft angle of no more than 2 degrees.

[0012] According to a further feature of one embodiment of the invention, the perimeter of the deck is continuous around the deck and the lower leg extensions are sized to fit within the perimeter when multiple similar pallets are stacked.

[0013] In accordance with a further feature of one embodiment of the present invention, the inwardly tapering inner surface of each of the hollow legs defines a generally rectangular horizontal cross-sectional shape, at least one edge of the rectangular horizontal cross-sectional shape being separated by the upper leg opening and the lower leg extension, the lower leg extension extending outwardly of the rectangular horizontal cross-sectional shape.

[0014] According to a further feature of an embodiment of the invention, at least one of the hollow legs adjacent a corner of the deck is formed with two of the peripheral support formations extending towards two adjacent edges of the pallet.

[0015] According to a further feature of an embodiment of the invention, the hollow legs are integrally formed with the deck.

[0016] According to a further feature of an embodiment of the invention, the hollow legs are mechanically attached to the deck. [Brief description of the drawings]

[0017] The invention is herein described, by way of example only, with reference to the accompanying drawings. [Figure 1] FIG. 1 is a schematic partial side view of a conventional non-nesting pallet. [Figure 2A] FIG. 1 is a schematic partial side view of a conventional nesting pallet. [Figure 2B] FIG. 2B is a schematic diagram of the functional limitations of the pallet of FIG. 2A in the context of racking. [Figure 2C] FIG. 2B is a schematic diagram of the functional limitations of the pallet of FIG. 2A in the context of stacking. [Figure 2D] FIG. 2B is a schematic diagram of the functional limitations of the pallet of FIG. 2A in a transportation context. [Figure 3A] 1 is an isometric view of a pallet constructed and operative in accordance with the teachings of one embodiment of the present invention; [Figure 3B] FIG. 3B is an enlarged view of the area indicated by I in FIG. 3A. [Figure 3C] FIG. 3B is an enlarged view of the area indicated by II in FIG. 3A. [Figure 3D] FIG. 3B is a plan view of the pallet of FIG. 3A. [Figure 3E] FIG. 3B is a side view of the pallet of FIG. 3A. [Figure 3F] FIG. 3B is an end view of the pallet of FIG. 3A. [Figure 3G] FIG. 3B is a cross-sectional view taken along line III-III in FIG. 3D. [Figure 3H]FIG. 3B is a bottom view of the pallet of FIG. 3A. [Figure 4A] FIG. 3C is an enlarged view of the foot of the pallet shown in the area indicated by IV in FIG. 3G. [Figure 4B] FIG. 4B is a cut-away isometric view of the foot of the pallet cut in plane VV of FIG. 4A. [Figure 5A] FIG. 3B is an isometric view showing two of the pallets of FIG. 3A nested inside one another. [Figure 5B] FIG. 5B is a cross-sectional view of the nested pallet of FIG. 5A through the plane indicated at VI. [Figure 6A] FIG. 3B is a cut-away isometric view of a corner leg of the pallet of FIG. 3A cut in a vertical plane parallel to the length of the pallet. [Figure 6B] FIG. 3B is a cut-away isometric view of a corner leg of the pallet of FIG. 3A cut in a vertical plane parallel to the width of the pallet. [Figure 7A] FIG. 13 is an isometric view of a pallet constructed and operative in accordance with the teachings of a further embodiment of the present invention. [Figure 7B] FIG. 7B is an enlarged view of the area indicated by VII in FIG. 7A. [Figure 7C] FIG. 7B is an enlarged view of the area indicated by VIII in FIG. 7A. [Figure 8A] FIG. 7B is a bottom isometric view showing two of the pallets of FIG. 7A nested inside one another. [Figure 8B] FIG. 8B is an enlarged view of the area indicated by IX in FIG. 8A. [Figure 9A] FIG. 13 is a schematic vertical cross-sectional fragmentary view through the legs of two nested pallets according to a further modified implementation of a pallet in accordance with an embodiment of the present invention, in which the lower leg extension deviates outwardly from the generally inwardly tapering contour of the legs. [Figure 9B] FIG. 9B is a partial isometric view of a leg of a pallet illustrating a first alternative implementation of the divergent lower leg extension of FIG. 9A. [Figure 9C] 9B is a schematic vertical cross-sectional partial view of a leg of a pallet illustrating a second alternative implementation of the divergent lower leg extension of FIG. 9A. FIG. [Figure 10]FIG. 13 is a schematic partial isometric view of a foot of a pallet according to a further alternative embodiment of the present invention. [Figure 11A] FIG. 13 is a schematic vertical cross-sectional partial view through a leg of a pallet according to a further embodiment of the invention, showing the pivotally retractable lower leg extension in an unfolded state; [Figure 11B] FIG. 13 is a schematic vertical cross-sectional fragmentary view through a foot of a pallet in accordance with a further embodiment of the present invention, showing the pivotally retractable lower leg extension in a retracted position; [Figure 12A] FIG. 13 is a schematic partial vertical cross-sectional view through a foot of a pallet according to a further embodiment of the invention, showing the slidably retractable lower leg extension in an unfolded state; [Figure 12B] FIG. 13 is a schematic partial vertical cross-sectional view through a foot of a pallet in accordance with a further embodiment of the present invention, showing the slidably retractable lower leg extension in a retracted position; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The present invention is a nestable pallet that provides improved racking and conveyor performance.

[0019] The principles and operation of a pallet according to the present invention may be better understood with reference to the drawings and the accompanying description.

[0020] Referring now to the drawings, Figures 3A-10 illustrate various implementations of nestable pallets, generally designated (100, 200, 300, 400), for supporting a load on a floor, constructed and operative in accordance with the teachings of an embodiment of the present invention. In general terms, a nestable pallet has a deck (102) that provides an upper surface for supporting a load, and a perimeter (104). A set of hollow legs (106) are rigidly integrated with the deck (102) and extend downwardly therefrom to support the deck on the floor. Each of the hollow legs (106) has an upper opening and an inwardly tapering inner surface (108) for receiving a portion of a corresponding leg of another pallet when multiple similar pallets are stacked.

[0021] The hollow legs may be some or all of the legs adjacent the perimeter (104), each having a peripheral support configuration including a lower leg extension (110) (see FIG. 4A) that projects horizontally from the inwardly tapering portion of the leg toward the edge (112) of the pallet defined by the downward projection of the perimeter (104), and an upper leg opening (114) for receiving the lower leg extension of another pallet when multiple similar pallets are stacked.

[0022] The advantages of this leg structure are easily understood. On the one hand, the legs maintain the overall preferred shape of the legs of the nesting pallets, which requires a large inward taper angle, preferably at least 3 degrees, typically about 4 degrees, to provide compact nesting and strength. This taper angle is determined by the nesting shape. For a pallet with a deck height of approximately 145 mm from the floor and a nesting depth of about 85 mm, i.e. a vertical step between successive pallets of about 60 mm, the gap between nested legs with a wall thickness of about 4 mm requires an angle of arctan (4 / 60), which approaches 4 degrees, making 4 degrees the preferred choice to ensure sufficient clearance and avoid wedging together of nested pallets. At the same time, by providing the lower leg extensions (110) that project towards the edge (112) of the pallet, the tips of the legs are very close to the edge of the pallet, thereby remedying various shortcomings of conventional nesting pallets as discussed above with respect to Figures 2B-2D. When nesting an empty pallet, the lower leg extensions (110) are received by the corresponding upper leg openings (114) of the underlying pallet, and the lower leg extensions preferably stack on top of the lower leg extensions of the underlying pallet when similar pallets are stacked, as illustrated in Figures 5A and 5B. As a result, the walls of the lower leg extensions may be vertical or nearly vertical, depending on the draft angle required to ensure release from the mold during manufacturing. A draft angle of less than 2 degrees is preferred, with a draft angle of around 1 degree typically being sufficient. Typical values ​​for these angles are illustrated in Figure 4A.

[0023] As a matter of terminology, when a taper, angle or slope is referred to herein as "inward" or "converging", this refers to a slope toward the center of the leg, such that the surface approaches the center as it moves from the deck to the base of the leg. Similarly, "outward" refers to a slope that moves away from the center of the leg as it moves from the deck to the base of the leg. Thus, the major inner surfaces (108) of all pallet legs described herein (other than in the region of the lower leg extension) are referred to as tapering inwardly.

[0024] The legs (106) are described as being rigidly integral with the deck (102). In a first set of preferred implementations, the legs and deck are integrally formed during a single injection molding manufacturing process. This option provides the highest strength-to-weight ratio and reduced manufacturing costs, but limits options for repairing damaged pallets. In an alternative preferred implementation (not shown), the leg structure may be manufactured separately and then attached using any suitable attachment format. Advantageously, the attachment of the legs uses a reversible form of attachment, such as a threaded fastener (screw or bolt) arrangement, thereby facilitating replacement and exchange of any damaged legs.

[0025] In the preferred but non-limiting implementation of Figures 3A-9B, the deck's perimeter (104) is continuous (uninterrupted) around the deck (102), thereby optimally contributing to the stiffness and strength of the pallet. The lower leg extensions (110) are therefore sized to fit within the perimeter when multiple similar pallets are stacked. The spacing between the opposing protruding lower leg extensions (110) at opposite ends of the pallet is therefore typically at least about 6 mm (3 mm at each edge) less than the outer dimensions of the deck to accommodate the wall thickness of the deck perimeter outside the upper leg openings (which can optionally be locally thinned compared to the wall thickness around the remainder of the deck perimeter). The inset of the lower leg extensions (110) relative to the pallet's edge (112) is preferably in the range of 6 mm to 20 mm, and most preferably 7 mm to 10 mm. By having the tips of the feet within 2cm of the edge of the pallet, and in some cases within 1cm of the edge, most of the limitations of conventional nesting pallets discussed above with reference to Figures 2B-2D are avoided and the pallet can be used with similar functionality as a non-nesting pallet.

[0026] In the pallet implementation (100), the lower leg extension is formed as an outward undulation of the leg wall, thereby forming part of the closed shape of the lower part of the leg. This is best seen in the view of the leg (106) shown in FIG. 4B, cut through a horizontal plane. As seen in this view, the inwardly tapering inner surface (108) of the hollow leg (106) defines a generally rectangular horizontal cross-sectional shape, at least one edge of which is separated by the upper leg opening and the lower leg extension, which extends outside of the rectangular horizontal cross-sectional shape. The "generally rectangular" shape is typically a rectangle with rounded corners, and the radius of the rounded corners may vary along the height of the leg as the horizontal dimension and shape change with the taper angle. Since most of the strength of the molded polymer legs is provided by these corners, the lower leg extension and upper leg opening are preferably implemented as modifications of the flat areas of the leg walls, leaving the corner areas complete along the entire height of the leg. As best seen in Figure 5B, a set of reinforcing ribs (116) are typically provided at the bottom of the hollow legs, as is common in the art, to provide additional rigidity and provide a surface for the feet of similar pallets to rest on when nested, thereby preventing over-fitting and squeezing of the pallets together. Also visible in Figure 4B is a slot (118) that may be optionally provided for the insertion of an RFID to support various pallet tracking functions.

[0027] The choice of the positioning of the peripheral support arrangements depends on the expected application. For example, in the case of racking, it may be sufficient to provide the peripheral support arrangements on the legs at either end of the short side of the pallet. However, to maximize application flexibility, it is typically preferred to provide the peripheral support arrangements along all four sides of the pallet. For this purpose, the hollow legs adjacent to the corners of the deck are most preferably provided with two of the peripheral support arrangements extending towards the two adjacent edges of the pallet, as can be seen for example in Figures 3B and 3C. In certain applications, for example in the context of a pallet conveyor system where a central pallet stop is used to align the pallet before turning, it may be preferred to also provide the peripheral support arrangements on the intermediate legs adjacent the long side of the pallet, thereby ensuring consistent alignment of the pallet by the pallet stop.

[0028] 7A-8B, there is shown a nestable pallet, generally designated (200), constructed and operative in accordance with a further embodiment of the present invention. Pallet (200) is generally similar to pallet (100) described above, and equivalent features are similarly labeled. Pallet (200) differs from pallet (100) primarily in that, instead of the generally rectangular legs (116) of pallet (100), legs (216) of pallet (200) are implemented with reduced size openings to provide greater continuity (smaller openings) with the upper surface of deck (102). By way of non-limiting example, the legs are shown implemented herein with a cross-sectional shape similar to that disclosed in U.S. Pat. No. 11,820,551, each having a horizontal cross-sectional shape consisting of the intersection of several relatively elongated shapes to form a generally T- or H-shaped leg. These shapes are modified by the addition of the peripheral support features described above, including lower leg extensions (110) and upper leg openings (114). In all other respects, pallet (200) is structurally and functionally similar to pallet (100), as will be clearly understood by analogy with the structure and function described and illustrated above.

[0029] 9A-9C, while the above embodiments illustrate the lower leg extensions (110) as being vertical or having a slight inward draft, an alternative implementation of the pallet (300) may have the lower leg extensions (110) angled outward toward the base of the leg, thereby ensuring that the closest point of contact with the underlying surface is at the point of the leg closest to the end of the pallet. This is shown diagrammatically in FIG. 9A, which shows the lower leg extensions to be a thickened portion of the wall of the leg. This thickened portion may be provided by attachment of the extension element, for example, by adhesive, heat welding, or any other suitable form of mechanical attachment. Alternatively, the lower leg extensions may be formed by the use of a suitable mold as part of the main injection molding process of the pallet's manufacture. FIG. 9B shows one possible implementation for injection molding, which requires a lateral moving core to form an outer rib structure to support the extensions. Figure 9C illustrates an alternative approach in which the mold is designed to form an outwardly sloping wall section of normal thickness to provide the lower leg extension (110). This can be accomplished by using a lower mold portion that extends upward into the interior volume of the leg in the region of the lower leg extension and a complementary upper mold portion that extends downward through the upper leg opening (114) to define the outer surface of the lower leg extension. Various design considerations for designing a mold to manufacture the implementations of Figures 9B and 9C will be apparent to one of ordinary skill in the art.

[0030] Referring now to FIG. 10, while all of the implementations described above maintain a continuous perimeter (104) around the deck (102), an alternative implementation of the pallet (400) uses upper leg openings (114) that extend to the perimeter of the pallet and create gaps in the perimeter (104). This may reduce the overall stiffness of the pallet, but allows the lower leg extensions to extend to the ends of the pallet, thereby more closely emulating the functionality of a non-nesting pallet. Pallet stiffness can be maintained through the use of reinforcing beams (120), typically formed from metal or reinforced polymeric materials, that are inserted along corresponding channels (122) along the length of the pallet (400) (shown in the figure during insertion). Incidentally, such reinforcing beams and channels are also advantageously used in the aforementioned embodiments, as illustrated by way of non-limiting examples in FIGS. 3A, 3F, 6B, 7A, and 9B.

[0031] As seen in FIG. 10, the portion of the leg (106) below the area that vertically overlaps during nesting of the pallets is preferably formed with a closed shape (in the horizontal plane), thereby maintaining most of the strength and rigidity of the leg structure.

[0032] Finally, referring to Figures 11A-12B, as an alternative to the rigid lower leg extensions of the above embodiments, pallets (500) and (600) according to the teachings of certain embodiments of the present invention use displaceable lower leg extensions (510 or 610) to provide extensions to some of the pallet legs during use (Figures 11A and 12A), and the displaceable lower leg extensions (510 or 610) retract to nest the pallet (Figures 11B and 12B). In these cases, the upper leg openings of the previous embodiments are not required, since the leg extensions retract to allow for nesting. If the leg extensions are contained within the internal volume of the legs when retracted, the lower leg openings are required to allow for outward projection of the leg extensions when deployed.

[0033] In the case of pallet (500), the lower leg extension (510) is pivotally mounted on pivot (512) and spring-biased by spring (514) towards the deployed state of Figure 11A. The lower leg extension (510) may be manually retractable for nesting, e.g., held in its retracted state by a catch mechanism (not shown) that releases upon nesting with the underlying pallet, such that it deploys automatically upon separation of the pallets. Alternatively, the shape of the corresponding surfaces of the extensions and legs may be such that the lower leg extension is mechanically displaced by the interaction of the two pallets during nesting, and retracts without manual intervention.

[0034] In the case of pallet (600), the lower leg extension (610) is slidably displaceable along a channel (612) defined in the pallet leg under the bias of a spring (614). As with pallet (500), similar options of manual retraction, with or without a catch mechanism, or retraction via mechanical interaction between pallets during nesting, are all possible implementations.

[0035] It will be appreciated that the above description is intended to serve as an example only, and that many other embodiments are possible within the scope of the invention as defined in the appended claims.

Claims

1. 1. A nestable pallet for supporting a load on a floor, comprising: (a) a deck having an upper surface for supporting the load and having a perimeter; (b) a set of hollow legs rigidly integrated with said deck and extending downwardly therefrom to support said deck on a floor, each said hollow leg having an upper opening and an inwardly tapering inner surface for receiving a portion of a corresponding leg of another pallet when a plurality of like pallets are stacked, each of a plurality of said hollow legs adjacent said periphery having: (i) a lower leg extension that projects horizontally from the inwardly tapered portion of the hollow leg toward an edge of the pallet corresponding to the downward projection of the outer periphery; and (ii) an upper leg opening for receiving the lower leg extension of another pallet when multiple similar pallets are stacked; a hollow leg including a peripheral support arrangement comprising: A nestable pallet comprising:

2. 2. A nestable pallet as claimed in claim 1, wherein said lower leg extension forms part of the closed lower shape of said hollow leg.

3. 2. A nestable pallet as claimed in claim 1, wherein the inwardly tapered portions of the hollow legs have a taper angle of at least 3 degrees and the lower leg extensions have a draft angle of no more than 2 degrees.

4. 2. The nestable pallet of claim 1, wherein the perimeter of the deck is continuous around the deck and the lower leg extensions are sized to fit within the perimeter when multiple like pallets are stacked.

5. 2. A nestable pallet as claimed in claim 1, wherein the inwardly tapering inner surface of each of the hollow legs defines a generally rectangular horizontal cross-sectional shape, at least one edge of the rectangular horizontal cross-sectional shape being separated by the upper leg opening and the lower leg extension, the lower leg extension extending outside of the rectangular horizontal cross-sectional shape.

6. 2. The nestable pallet of claim 1, wherein at least one of the hollow legs adjacent a corner of the deck is formed with two of the peripheral support formations extending toward two adjacent edges of the pallet.

7. 2. A nestable pallet according to claim 1, wherein said hollow feet are integrally formed with said deck.

8. 2. The nestable pallet of claim 1, wherein said hollow feet are mechanically attached to said deck.

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