Pallet with Magnetic Anti-Tipping Feature

Abstract

A pallet includes a deck and a plurality of legs extending downward from the deck. At least one permanent magnet is disposed on the underside of the deck adjacent to at least one tine entry location defined between the legs. The magnet is configured to attract the tines of a forklift to provide a magnetic retention force that resists tipping of the pallet when lifted and moved by the forklift. Preferred examples include nestable polymer pallets.

Claims

1. A pallet for lifting by a forklift, the pallet comprising: (a) a deck; (b) a plurality of hollow legs extending downward from the deck and defining a plurality of tine entry locations between the legs; and (c) at least one permanent magnet disposed on an underside of the deck adjacent to at least one of the tine entry locations, the magnet configured to attract the tines of the forklift to provide a magnetic retention force that opposes tipping of the pallet when lifted by the forklift.

2. The pallet of claim 1, wherein the pallet is a nestable polymer pallet and wherein the legs are hollow and configured for nesting with legs of other similar pallets.

3. The pallet of claim 1, further comprising skids extending between the legs, the magnet being disposed adjacent to a tine entry location beneath which the skids do not pass.

4. The pallet of claim 1, wherein the permanent magnet is disposed on the underside of the deck adjacent to at least two tine entry locations.

5. The pallet of claim 4, wherein the deck is rectangular, and the magnets are disposed adjacent to two tine entry locations on each of two opposite sides of the deck.

6. The pallet of claim 4, wherein the deck is square, and the magnets are disposed adjacent to two tine entry locations on each of four sides of the deck.

7. The pallet of claim 1, wherein the pallet is a rectangular pallet having a longer side and a shorter side, and wherein the magnets are disposed adjacent to two tine entry locations on each of the shorter sides.

8. The pallet of claim 1, wherein the magnetic retention force provided by the at least one permanent magnet adjacent to one tine entry location is between 40 N and 100 N.

9. The pallet of claim 5, wherein the combined magnetic retention force provided by the magnets adjacent to two tine entry locations on a single side of the deck is between 40 N and 100 N.

10. The pallet of claim 6, wherein the combined magnetic retention force provided by the magnets adjacent to two tine entry locations on a single side of the deck is between 40 N and 100 N.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The invention is herein described, by way of example only, with reference to the accompanying drawings, wherein:

[0016] FIG. 1 is an isometric view of a pallet according to the present invention, shown from above;

[0017] FIG. 2 is an isometric view of the pallet of FIG. 1, shown from below; and

[0018] FIG. 3 is a schematic side view of the pallet of FIG. 1, shown asymmetrically back-loaded and raised on tines of a forklift.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] The present invention is a pallet with a magnetic anti-tipping feature. By way of one particularly preferred but non-limiting exemplary embodiment, FIGS. 1-3 show a pallet 10 having a deck 12 and a plurality of hollow legs 14 that extend downward from deck 12. The spaces between legs 14 along at least one side of the pallet define tine entry locations 16 for insertion of tines of a forklift or pallet jack to lift the pallet and its load.

[0020] The pallet 10 also includes at least one permanent magnet 18 disposed on an underside of the deck 12 adjacent to at least one of the tine entry locations 16 defined between the legs 14. The magnet 18 is configured to attract the tines 22 of a forklift 20 when the pallet 10 is lifted, providing a magnetic retention force Fm that resists tipping.

[0021] This simple addition of magnets 18 creates a significant improvement in the stability of the pallet 10 during lifting and maneuvering operations. The magnetic retention force Fm, while relatively small in magnitude, generates a substantial anti-tipping moment M2 due to the lever arm d2 created by the distance between the magnets 18 and the tips of the forklift tines 22. This anti-tipping moment M2 counteracts the static and/or dynamic tipping moment M1 caused by an asymmetrically distributed load, by the tines 22 not being fully inserted into the pallet 10 and/or due to horizontal acceleration during use.

[0022] As shown in FIG. 3, when pallet 10 is asymmetrically loaded and lifted by a forklift 20, a tipping force F acts on the center of gravity of the load. This force generates a tipping moment M1 that tends to rotate the pallet 10 around the tips of tines 22. Additionally, a dynamic tipping moment results from inertia of a load, particularly when piled high, under acceleration of the pallet, such as when a forklift truck backs up while carrying the pallet. The magnetic retention force Fm acting on the tines 22 creates an opposing anti-tipping moment M2 which is preferably sufficient to overcome both static and dynamic tipping moments which may be generated during a wide range of usage scenarios.

[0023] The lever arm d2 associated with the magnetic retention force Fm is significantly greater than the lever arm d1 associated with the static tipping force F. This means that a relatively small magnetic retention force Fm can effectively counteract a much larger tipping force F, preventing the pallet 10 from tipping over. The retaining force required to overcome the dynamic tipping moment will depend on the mass and loading height of loads expected to be carried, as well as the horizontal accelerations likely to be encountered.

[0024] The invention is particularly applicable to pallets in which no tip-limiting structure, such as a lower deck or skids, passes below the tine entry locations. In one particularly preferred subset of embodiments, this may be a nestable polymer pallet with legs 14 configured for nesting with legs of other similar pallets, enabling efficient stacking when the pallets are empty. The invention is however also applicable to non-nesting pallets including pallets with skids. In the latter case, the magnets are disposed adjacent to a tine entry location beneath which the skids do not pass.

[0025] Pallet 10 is formed from any suitable material, including polymer materials such as polypropylene or polyethylene, and may be made by any suitable method, such as by injection molding. By way of one non-limiting example, pallet 10 may have dimensions of approximately 1200 mm by 800 mm or 1200 mm by 1000 mm, which are standard sizes for many logistics applications. The pallet 10 may be implemented with nine legs 14, although other numbers of legs are also possible.

[0026] The magnets 18 may be ferrite magnets, which are cost-effective, durable, and provide sufficient magnetic force for this application. Other suitable magnetic materials, such as neodymium magnets or samarium cobalt magnets, may also be used.

[0027] The term adjacent is used herein in the description and claims to describe positioning of magnets 18 such that they are reliably aligned with tines inserted at the tine entry locations 16 and are not distant from the edge of the deck: magnets 18 are preferably positioned on the underside of the deck 12, spaced a short distance (e.g., 1-20 cm) from the edges of the deck 12 to avoid unintended engagement with other magnetic objects, and are typically positioned roughly centrally within, e.g., in the middle third of the width of, the tine entry paths so as to accommodate slight variations in spacing between the tines while maintaining overlap with the tines. Magnets 18 may be fixed in place by bolting or by overmolding during the manufacturing process.

[0028] In some embodiments, pallet 10 may have magnets 18 adjacent to two tine entry locations 16 on each of the two shorter (e.g., 800 mm or 1000 mm) sides. This configuration is suitable for rectangular pallets where there is a preferred tine entry direction. Additionally, for rectangular pallets, when lifted by tines entering from the longer side, the tines will typically extend across and support the entire smaller dimension of the pallet, thereby rendering the chances of tipping greatly reduced.

[0029] In other embodiments, pallet 10 may have magnets 18 adjacent to two tine entry locations 16 on each of the four sides. This configuration is particularly suitable for square pallets where the tines 22 can be inserted from any side.

[0030] The number of magnets 18 per tine entry location 16 can vary. In some embodiments, a single magnet 18 per tine entry location 16 is sufficient. In other embodiments, two or more magnets 18 per tine entry location 16 may be used to increase the magnetic retention force Fm. Optionally, the magnetic retention force may be adjustable according to the parameters of a given usage scenario by installing more or fewer magnets.

[0031] The magnetic retention force Fm provided by the magnets 18 is preferably in the range of 40 N to 100 N. This force is sufficient to resist tipping without interfering with the normal handling of the pallet 10 by a forklift 20 or pallet jack. This force is typically the sum total of the magnetic retaining force for a give entry direction of a forklift, which may be the combination of magnets locking onto two tines or may be provided by one or more magnets attracting only one of a pair of tines inserted from a given side. Depending on details of particular applications, retaining forces below 40 N or above 100 N may also be appropriate in certain cases.

[0032] When the pallet 10 is lifted by a forklift 20, the tines 22 enter the tine entry locations 16 and come into contact with the magnets 18. Magnets 18 attract the tines 22, locking on to the tines so as to create an additional retention force Fm that helps to prevent the pallet 10 from tipping.

[0033] Even if the load on the pallet 10 is unbalanced or the tines 22 are not fully inserted, the magnetic retention force Fm provides a counteracting moment M2 that resists tipping. This significantly improves the stability of the pallet 10 during lifting operations, reducing the risk of accidents and damage to goods.

[0034] Magnets 18 may be oriented with their north-south axis horizontal. This configuration allows the magnetic flux to close through the metal of the tine 22, increasing the magnetic attraction. In some embodiments, the magnets 18 may be formed as (possibly flattened) horseshoe magnets to further enhance this effect.

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