WO1992012906A1

WO1992012906A1 - Pallet

Info

Publication number: WO1992012906A1
Application number: PCT/AU1992/000018
Authority: WO
Inventors: John Hood Clark; Colin Gregory Murphy; John Stanislaw Kajdrys
Original assignee: Comalco Aluminium Limited
Priority date: 1991-01-17
Filing date: 1992-01-17
Publication date: 1992-08-06
Also published as: CA2078433A1; JPH05505377A; EP0521126A1; AU1184992A; EP0521126A4

Abstract

A plastic molded pallet for coils of metal has a base (10), a series of support legs (12) to permit insertion of the forks of a forklift truck from a multiplicity of directions and a centrally located upstanding dowel (11) for engaging within the central cavity of a coil for restraining movement of the coil in a plane parallel to the base during shipment. A complementary lid (20) may be used with upstanding location means (26) for locating the support legs (12) of another pallet placed in the stack and location means (27, 28) for tiedown strapping is provided for securing a coil and engaging firmly the edge of a coil even when of lesser diameter than that the lid (20).

Description

-PALLET" TECHNICAL FIELD The present invention relates to pallets for shipping purposes and is especially concerned with the shipment of coils of metal strip but the invention may be equally applicable to the shipment of other products particularly in coil form but not necessarily so.

BACKGROUND ART During transportation/ a pallet may be subjected to severe forces due to impact when the pallet and its load is picked up and deposited by a forklift truck and furthermore during transportation forces are imposed due to substantial accelerations and decelerations. For example, when the pallet is being moved by rail, during shunting operations to prevent damage to the product on the pallet, the pallet must support the product and restrain movement.

Substantial economic loss occurs, for example, in relation to coils of thin aluminium strip where movement of the coil occurs on a conventional pallet thereby damaging the coil. It has been now found that strapping the coil onto a pallet, with the axis of the coil being vertical, does not adequately restrain movement of the coil and damage has easily occurred. The user of the coil will typically be intending to manufacture aluminium cans for beverages and any damage to the strip must be removed since such damaged strip cannot be used in precision machinery. Not only is there a loss of valuable aluminium strip but also machine down-time and labour cost contribute to the economic loss.

Thus, there has been a long standing problem of damage to coils of aluminium which typically weigh around six tonnes, have a diameter of around 1.4 meters and a width of around 1.5 meters. Attempts to protect the coil from movement on a timber pallet have included nailing timber battens to the upper surface of the pallet to attempt to restrict movement of the coil and also placing a thick rubber mat under the coil before it is placed on the pallet. In an attempt to further protect the coil it has been wrapped in plastic sheet material and strapped to the pallet.

Another approach that has been proposed involves the formation of a pallet from two moulded plastic halves which interengage and have an upstanding lip. The periphery of the pallet is secured by a steel band which pulls the two halves towards one another so that the lip engages around the periphery of the coil. However these pallets are expensive, heavy and only a very small range of adjustment is possible to accommodate coils of different diameter. This results in substantial capital investment for a range of pallet sizes for a typical aluminium strip product plant as significant variation in coil diameter occurs in practice. The capital cost of such pallets is a serious disadvantage as, for many consignments involving export, it is not practicable or feasible to return the pallets for further use. The pallets are of special purpose design and would have not general utility for shipment.

DISCLOSURE OF INVENTION The present invention consists in one aspect, in a pallet suitable for shipment of coils of metal strip or similar products and comprises a base for supporting the product, support means connected to the base and shaped and dimensioned for supporting the base and providing a clearance under the base for the insertion of forks of a forklift truck, and a centrally located dowel connected to the base and projecting upwardly therefrom for engaging within a central cavity in the product for restraining movement of the product in a plane parallel to the base.

Preferably the dowel is of circular shape and tapered upwardly to facilitate location and engagement of the cavity in the product. Advantageously the dowel can be of the order of 25mm to 75mm in height. When the invention is used for transporting coils of metal strip, the dowel typically will have a diameter of about 250mm and a taper of a few percent over the height of the dowel has proven to be convenient and satisfactory.

Advantageously, embodiments of the invention are formed with the base of circular shape whereby a high density of packing of pallets can be achieved. Alternatively the base could be of polygonal shape of at least five sides again to achieve high density packing. For example it has been found that a standard shipping container will accommodate only three conventional timber pallets but four pallets in accordance with the present invention can be accommodated in the same space thereby offering substantial economic advantage.

In a preferred embodiment, the support means comprises a multiplicity of legs in spaced array and most preferably the array permits the forks of a forklift truck to be inserted from any one of four directions.

Most preferably the array of legs includes a central space for accommodating the dowel of another pallet so that an interengaged stack can be formed.

In a preferred embodiment, the pallet is formed as a single plastic moulding and it has been found that this can be achieved economically by low pressure injection moulding in polypropylene. For the purpose of shipping six ton coils of aluminium strip, it has been found that a relatively cheap, lightweight and durable pallet can be formed. Typically the pallet will weigh only about 16KG and the pallet is of competitive price having regard to its durability compared to timber pallets. Such a pallet is considered to be economic for export where return of the pallet is not feasible and in any event the pallet is of valuable plastic material which can be recycled to form other products after shipment of the coil.

In another aspect the invention extends to a lid of suitable form for use on a coil supported on a pallet and the invention also extends to a method of shipment using such items.

BRIEF DESCRIPTION OF DRAWINGS For illustrative purposes only, an embodiment of the invention will be described with reference to the accompanying drawings of which:-

Figure 1 is a perspective view from above of a pallet;

Figure 2 is a side elevation of the pallet; Figure 3 is a sectional side elevation of the pallet taken along the line A-A in Figure 4; Figure 4 is a plan view of the pallet; Figure 5 is an inverted plan view of the pallet; Figure 6 is a plan view of a complimentary lid to be used with the pallet of Figures 1 to 5; and

Figure 7 is a cross sectional view taken along the line B-B of Figure 6.

MODES FOR CARRYING OUT THE INVENTION The pallet and lid illustrated are each integrally formed in polypropylene by low pressure injection moulding in a single operation. The pallet comprises a circular base 10, having an upstanding peripheral lip 9, an integral upstanding dowel 11 and array of twelve support legs 12. The dowel is slightly tapered, has an internal cross-shaped strengthening wall 17, and is of the order of 50mm high. The pallet diameter is 1590mm and thus can accommodate a wide range of coil sizes. Each of the support legs is hollow and slightly tapered and stiffened by a set of radially outwardly extending buttress walls 15, and a cross-shaped interior webbing 16. In the case of the buttress walls 15A reaching the periphery of the base, the buttress is the full depth of the support legs but the other buttress walls 15 terminate short of the bottom of the support leg. As illustrated in figure 5 by arrows a forklift truck can insert its forks in any one of four directions under the pallet. This facilitates pallet handling is an advantage over many one-trip pallets where strip-like supports for the base are used thereby restricting access of forks to two directions. Furthermore the array of legs provides a high degree of stability irrespective of direction of any loads or forces during transportation.

The base also includes a series of four notches 13 each defined by respective pairs of parallel walls 14 for accommodating strapping which can facilitate holding in place protective plastic sheeting.

Referring now to the lid of Figures 6 and 7, the lid 20 is of the same overall diametar as the pallet 10. The lid comprises a thin plastic disc-shaped portion 21 with a downwardly extending peripheral skirt 22 interrupted at four equally spaced locations 23, a central depending collar 24 and, extending from the upper surface, a central smaller location collar 25 and an array of location rings 26.

The location rings 26 are dimensioned to accomodate and locate the bases of the support legs 12 of another pallet which may be placed on top of the lid to form a stack. Similarly the collar 25 is dimensioned and located to cooperate with the rings and depending collar 24 of another lid so lids may be stacked and located for shipment and storage.

A series of four identical tie locators 27 are provided equally spaced around the lid, the radially outer portion of each locator being where there is an interruption 23 in the peripheral skirt 22. Each locator comprises a pair of spaced upstanding walls 28 extending substantially radially so that a tiedown strap passes between the walls and over the edge of the lid to secure the lid and a coil onto a supporting pallet. A series of transverse grooves or slots 29 are provided in the plastic material between the walls 28 thereby providing lines of weakening. When a strap-like tie is tensioned over a coil having an external diameter less than the full diameter of the lid, the plastic material can shear along one or more of the grooves to tighten the tie so as to bear on the edge of the coil.

A further feature which may be utilised is the provision of packing rings, the external dimension of the upstanding dowel 11 on the pallet being chosen to represent the smallest diameter used on a coiling machine. If machines providing a greater coil diameter are used then packing rings are simply inserted to make the coil a snug fit.

The present invention can be applied in plastics material such as polypropylene which readily can be recycled when pallets become damaged. It is envisaged that a multiplicity of trips will be completed before pallet damage is likely. It is then a simple matter to reuse the material to make further lids and pallets.

Embodiments of the invention can be utilised with plastic wrapping materials so that a completely weather tight package is provided to protect valuable products such as thin aluminium strips when in transit from the place of manufacture to the place of utilisation. Embodiments of the invention permit fast, safe and reliable handling with minimal chance of coil damage and wastage compared with conventional palletisation and delivery systems.

Claims

1. A pallet suitable for shipment of coils of metal strip or similar products and comprising a base for supporting the product, support means connected to the base and shaped and dimensioned for supporting the base and providing a clearance under the base for the insertion of forks of a forklift truck, and a centrally located dowel connected to the base and projecting upwardly therefrom for engaging within a central cavity in the product for restraining movement of the product in a plane parallel to the base.

2. A pallet is claimed in claim 1, and wherein the dowel is of circular shape and tapered upwardly to facilitate location and engagement of the cavity in the product.

3. A pallet is claimed in claim 1 or claim 2 and shaped and dimensioned for transporting a coil of metal strip which is of the order of 1.5m diameter and 1.5m width, the dowel having a height of about 50mm. 4. A pallet as defined in any one of the preceding claims and integrally formed by moulding in a high strength, durable plastics material.

5. A pallet as defined in any one of the preceding clauses, wherein the base is of circular shape. 6. A pallet as defined in any one of the preceding claims, wherein the base has an upstanding lip.

7. A pallet as defined in any one of the preceding claims, wherein the support means comprises a multiplicity of legs in spaced array, and wherein the array permits the forks of a forklift truck to be inserted from any one of four directions.

8. A pallet as defined in any one of the preceding claims, wherein the support means comprises a set of approximately 12 separate legs some which are adjacent the dowel and the others of which are adjacent the periphery of the base, each leg being of substantially circular cross-sectional shape and having a centre located on a square imaginery grid. 9. A pallet as defined in any one of the preceding claims, wherein each support leg is hollow with a cross-webbing internal wall and a plurality of external buttress walls. 10. A pallet as defined in claim 8 and claim 9, and wherein each buttress wall extends at approximately 45° to the lines of the imaginery square grid.

11. A protective lid for use in cooperation with a pallet as defined in any one of the preceding claims and comprising a disc-like base, upstanding location means for locating the support means of another pallet to be placed on top of the lid, peripheral depending means for engaging over the edge of a coil on which the lid is to rest and means for locating tiedown strapping whereby a coil and the lid may be secured to a supporting pallet.

12. A lid as claimed in claim 11 and wherein the locating means comprises a pair of upstanding walls extending inwardly from the edge of the lid at at least two diametrically opposed locations to provide a pair of locating means and weakening means being provided in the lid material between the walls whereby tiedown strapping bends or breaks the plastic material through the weakening means so as to bear tightly along the edge of a coil having a diameter less than the full diameter of the lid. 13. In combination of pallet as claimed in any one of claims 1 to 10 and a lid as claimed in claim 11 or claim 12.

14. A method of shipping coils of metal strip or similar products and comprising placing the coil on a pallet as claimed in any one of claims 1 to 10.

15. A method as claimed in 14 and further comprising applying a lid as claimed in claim 11 or claim 12 to the coil when supported on a pallet and applying tiedown strapping to secure the lid and coil on the pallet. [received by the International Bureau on 03 July 1992 (03.07.92); original claims 2 cancelled; original claim 1, amended; new claims 13, 14, 17 -19 added; claims 3 - 13 amended and renumbered as claims 2 - 12; claims 14 and 15 replaced by new claims 15 and 15 (3 pages)]

1. A pallet suitable for shipment of a coil of metal strip having a central cavity in an end of the coil which is to be supported on the pallet, the pallet comprising a base for supporting the product, support means in the form of a spaced array of legs connected to the base and shaped and dimensioned for supporting the base and providing a clearance under the base for the insertion of forks of a forklift truck from a multiplicity of directions, and a centrally located tapered dowel connected to the base and projecting upwardly therefrom for engaging within the central cavity in the coil for restraining movement of the coil in any direction in a plane parallel to the base. 2. A pallet as defined in claim 1 and shaped and dimensioned for transporting a coil of metal strip which is of the order of l.5m diameter and 1.5m width, the dowel having a height of about 50mm.

3. A pallet as defined in any one of the preceding claims and integrally formed by moulding in a high strength, durable plastics material.

4. A pallet as defined in any one of the preceding clauses, wherein the base is of circular shape.

5. A pallet as defined in any one of the preceding claims, wherein the base has an upstanding peripheral lip.

6. A pallet as defined in any one of the preceding claims, wherein the support means comprises a multiplicity of legs in a uniformly spaced array, and wherein the array permits the forks of a forklift truck to be inserted from any one of four directions spaced at 90° to each other.

7. A pallet as defined in any one of the preceding claims, wherein the support means comprises a set of approximately 12 separate legs some which are adjacent the dowel and the others of which are adjacent the periphery of the base, each leg being of substantially circular cross-sectional shape and having a centre located on a square imaginary grid.

8. A pallet as defined in any one of the preceding claims, wherein each support leg is hollow with a cross-webbing internal wall and a plurality of external buttress walls.

9. A pallet as defined in claim 8, and wherein each buttress wall extends at approximately 45° to the lines of the imaginary square grid.

10. A protective lid for use in cooperation with a pallet as defined in any one of the preceding claims and comprising a disc-like base, upstanding location means for locating the support means of another pallet to be placed on top of the lid, peripheral depending means for engaging over the edge of a coil on which the lid is to rest and means for locating tiedown strapping whereby a coil and the lid may be secured to a supporting pallet.

11. A lid as claimed in claim 10 and wherein the locating means comprises a pair of upstanding walls extending inwardly from the edge of the lid at at least two diametrically opposed locations to provide a pair of locating means and weakening means being provided in the lid material between the walls whereby tiedown strapping bends or breaks the plastic material through the weakening means so as to bear tightly along the edge of a coil having a diameter less than the full diameter of the lid.

12. In combination of pallet as claimed in any one of claims 1 to 9 and a lid as claimed in claim 10 or claim 11.

13. A pallet as defined in any one of claims 1 to 9 when in use for transporting or storing a coil of metal strip, the coil of metal strip having a central circular cavity directly or indirectly mounted on and engaging with the dowel whereby bilateral movement is restrained.

14. A pallet as defined in claim 13 and further comprising using a lid as defined in claim 10 or claim 11.

15. A method of shipping coils of metal strip and comprising placing the coil on one axial with its cental cavity engaged on a pallet as claimed in any one of claims 1 to 10.

16. A method as claimed in 15 and further comprising applying a lid as claimed in claim 10 or claim 11 to the coil when supported on a pallet and applying tiedown strapping to secure the lid and coil on the pallet.

17. A pallet suitable for shipment of coils of metal strip or similar products and comprising a base and wherein the support means comprises a symmetric array of spaced support legs integrally formed with the base, the legs comprising a first group of legs located near the periphery of the pallet and a second group of legs located near the central region of the pallet and the array providing spaces for the insertion of the forks of a forklift truck from four different directions spaced by ninety degrees.

18. A pallet as defined in claim 17 and wherein there are eight legs in the first group of legs and four legs in the second group of legs.

19. A pallet as claimed in claim 17 or claim 18 and wherein the dowel is a shallow upwardly tapering dowel of circular cross-sectional shape.