Improvements in or relating to freight container utilisation and to a pallet therefor

Abstract: The present invention relates to the transport of cargo in containers, especially cargo which would usually be transported as bulk cargo, for example coils of sheet steel. The problem of securely loading cargo within a container is overcome by the present invention by utilising a plurality of pallets which in combination occupy the floor space of a container and using the required number of pallets, whether loaded or not, to provide pallet load location and restraint. For the anticipated bulk cargo comprising loads of up to 10 tonnes, and between 10 and 25 tonnes, two pallet sizes are envisaged with latter being twice as long as the former. The preferred pallets have a width equal of the width of the container. For a container capable of carrying 30 tonnes, three load configurations are contemplated, namely: - four of the shorter pallets with each loaded at say 7 tonnes, two of the large pallets with each loaded at say 13 tonnes, or one large pallet and two small pallets with only the large pallet loaded at say 25 tonnes. The unloaded pallets serve as localised restraint for the loaded pallet. The invention further proposes a pallet (I or II) for use in the method comprising a pair of laterally spaced longitudinally extending ground contacting surfaces 9 which serve to distribute load to the outer one third of the width thereof. The centre one third is clear. The pallet further comprises a load receiving cradle which provides longitudinal restraint between oppositely inclined surfaces (10,11). Adjustable lateral restraint means is provided including repositionable legs 24 upstanding from the load receiving cradle or bars 150 which are pivotally and slidably adustably mounted with respect to the pallet for lateral adjustment.

Description: The present invention relates to the transportation of objects by container, a modular container palletisation system, and to a pallet for use in transporting goods by container. The invention has particular application to the transportation of metal coils, especially coils of sheet material, especially steel coils, or other high value products such as paper aluminium coils, or organic or other high value coated steel coils, but without limitation to same. It provides a means by which goods which are usually transported as bulk freight can be containerised. Historically the transportation of goods by road, rail or water involved loading individual items and was labour intensive. Cranes provided assistance for handling some loads and the advent of the fork lift truck led to the introduction of palletised loads which avoided handling of individual items when transferring between different types of transport at freight terminals. Palletised loads still offered limitations in relation to the speed of handling and especially in relation to their stacking capacity. This has led to development and widespread adoption of containers. Various sizes have now become standardised 20' (6m) long containers are the most common. The width has become standardised at 2438 mm. Containers can be loaded at source and are easily transferred from different types of transport e.g. road, rail or ship. Forklift trucks can be used to load a container with palletised loads. Pallets are approximately 48" x 40" (1200-1000 mm) square. Ten pallet places can be accommodated in a standard container. Large ocean going vessels have been designed for handling the containers which can be stacked one on top of the other perhaps as many as seven high. Containers have the advantage of offering protection to the contents within. There is a constant flow of containers around the globe to meet the requirements for the supply of raw materials and products. To maximise container utilisation it is desirable to be able to fill a container whenever it is moved from one location to another, but- it has been calculated that 20% of containers are transported empty on re-positioning runs. EP -A-0596755 discloses the use of sub-containers that are of a size to permit multiple sub-containers to be accommodated cross wise on a standard ISO flat bed container. The sub-containers are individually secured to the flat bed container. Some products are still transported as bulk loads. One of the products which is still most frequently transported as a bulk load on board ship is steel coil. These vary in weight between 7 tonnes and 25 tonnes. The coils are stored in dockside warehouses which have a large capacity say of the order of 20,000 to 50,000 tonnes. The capacity has to be large enough to cover the required demand for steel coils between shipments. If a more regular supply chain could be established the need for these warehouses could be reduced. The transportation of the likes of steel coils as bulk cargo exposes the coils to potential damage be it mechanical damage or that resulting from exposure to sea water. Often the base material is provided with a high value coating such as an organic paint finish which needs to be protected against damage. For bulk cargo this has led to the encapsulation of the coils. Because containers can be sealed against water ingress, the need for additional protective packaging could be avoided if the coils were transported in containers and it would be particularly advantageous if it was possible to use containers which would otherwise be empty. There are frequent container shipments and the ability to utilise containers for shipment of the likes of steel coils would provide a possible solution to the above mentioned problems. However, there is a problem with the utilisation of the existing construction of containers for the shipment of small high weight loads because, whilst the containers are designed to carry up to 30 tonnes; the weight has to be evenly distributed over the floor. A typical design of pallet comprises 3 or 4 longitudinal wooden bearers interconnected by a number of longitudinally spaced laterally extending planks providing a load surface for the pallet. Placing a coil of steel, say a 7 tonne coil of steel, on a pallet of this design, say with its axis vertical for stability reasons, would impart localised loading on the container floor which would exceed its design capacity when supplemented by the dynamic loads imposed during transportation at sea. US -A-5413054 discloses a one piece plastic cradle pallet. The pallets have pairs of integrally formed triangular formations to locate coils and are configured to nest with identical pallets for transportation purposes. The pallets have three longitudinal legs that are spaced apart laterally. One is set along the longitudinal centre line of the pallet and the other two are inset from the lateral edges of the pallet. In theory a container could carry 3 x 7 tonne coils, 2 x 13 tonne coils or one 25 tonne coil. In addition to the above mentioned weight distribution problem, there is a further problem of how to load such heavy weights into a container. Various designs of fork lift truck have the capacity to lift palletised loads of 7 tonnes, 13 tonnes and even 25 tonnes, but they can only deposit the load into the rear of the container. Open frame containers have been developed which permit side loading, or loading by way of a crane, but there are relatively few of these containers in circulation. In order to improve container utilisation a system needs to be developed which facilitates the transportation of such large weights. Another problem which has detracted from the utilisation of containers for transportation of such large weights is the need to ensure secure stowage of the likes of steel coils within the container. Such large weights could easily burst their way through the container sides and the traditional approach to securing loads is to brace the load within the container, typically using wood. The construction of wooden bracing is time consuming and its subsequent disposal and/or recycling further adds to the cost. The EEC Directive on Packaging and Packaging Waste 94/62 EEC will have far reaching effects on the costs of producing and transporting of goods which requires considerable packaging. The above factors have conspired to render the bulk transportation of steel coils the most appropriate means of transportation of such items until now. The present invention aims to provide a solution. Accordingly, a first aspect of the invention provides a modular container palletisation system comprising a container and a plurality of generally rectangular pallets having at least two different sizes wherein the width of each pallet equals the internal width of the container and wherein the length of a plurality of pallets in combination equals the internal length of the container, wherein a number of said pallets are used in combination to provide pallet location and restraint within the container with the pallets occupying the full width and length of the container and with at least one pallet carrying the load, and wherein each pallet comprises oppositely disposed side members serving as abutments which in use limit lateral movement within a container and further comprising ground engaging support members extending in from opposite lateral sides of the pallet and disposed spaced apart to opposite sides of a longitudinal centre line of the pallet, and comprising means for locating a load, when present, longitudinally and laterally with respect to the pallet. By using the pallets in combination whether loaded or not, the need for additional bracing materials is avoided. The length is a fraction of the length of the container. More preferably different sizes of pallets are utilised at least as concerns the length. More preferably still the different lengths are related. It is preferred to employ two different sizes of pallets with the longer of the two being a multiple of the shorter. In the preferred embodiment four of the shorter pallets occupy the full length of a 6m container. Preferably a longer pallet is twice as long as a shorter pallet. Such a combination allows four shorter pallets to be used in one configuration. In another configuration, two longer pallets are used, or in a third configuration one longer pallet and two shorter pallets are used. By using pallets in this configuration, the load can be distributed along the length of the container. In a preferred embodiment the load supporting cradle provides one of the longitudinal and lateral locating means and further means is provided to provide the other of the lateral and longitudinal locating means. In an alternative embodiment the cradle provides both the lateral and longitudinal locating means. More particularly the load supporting cradle comprises a pair of longitudinally spaced laterally extending elongate members. More preferably still the load supporting cradle comprising means which is configured to contact the load. Where the load is a coil said means contacts an arcuate part of the load. Said means may comprise a part cylindrical contact surface or a pair of part cylindrical contact surfaces. Conveniently these may be covered by a resilient material which acts to cushion the load as well as to distribute the forces into the load supporting cradle. In a preferred embodiment, the means which is contacted by the load comprises a pair of oppositely inclined surfaces defining a V-shape to receive the load nestling therebetween. The inclined surfaces are backed up by one or more gussets which are preferably orientated in the longitudinal direction and abut the ground engaging support members to distribute the load thereto. Preferably the means for locating and holding the load laterally is laterally adjustable to cater for different widths of load. Said means may comprise laterally movably adjustable bar means. In one embodiment said means are conveniently releasably relocatable in aperturing therefor. Said means may be mounted in alternative orientations. In a first orientation said means functions as a lateral abutment for the load. In a second orientation, the upper end provides a spigot by which two pallets can be located with respect to one another, one on top of the other. Two spigots are provided for each pallet. In an alternative embodiment a pair of bars means are provided and each comprise an elongate element which extends across the cradle and is movably adjustably in the lateral direction. Means is provided for locating the bar means with respect to the pallet. Preferably the bar means is pivoably and slidably connectable with the cradle. A rack having a plurality of notches facilitates locating the bar means in a selected lateral position. Adjustable strapping may be further provided to resist lateral telescoping of the load. Conveniently the pallet has aperturing permitting entry from one or both ends to receive the forks of a fork lift truck. More particularly the pallet has a recess open to the underside thereof to permit use with spaced elongate load carrying tracks employed with mating trolleys for movement of the pallets within a container. The different sizes of pallet are constructed similarly. Another aspect of the invention provides a method of locating a load within a container utilising a plurality of generally rectangular pallets having at least two different sizes wherein the width of each pallet equals the internal width of the container and wherein the length of a plurality of pallets in combination equals the internal length of the container, the method comprising selecting a number of said pallets so that the width and length of the plurality of pallets in combination equals the internal width and length of the container, determining the maximum number of loaded pallets which can be accommodated in the container having regard to its weight carrying capacity, determining the proportion of container floor area which is occupied by the maximum number of loaded pallets which can be accommodated in the container, selecting the number of unloaded pallets, if any, which are required to occupy the unoccupied space, and positioning the loaded pallets and any unloaded pallets into the container in a sequence which will distribute the load most evenly over the floor of the container, providing pallet location and restraint within the container. The present invention will now be described further by way of example only with reference to the accompanying drawings in which:- Figures 1 & 2 are perspective views of two sizes of pallet, Figures 3, 4 & 5 are cut away perspective views illustrating how the two different sizes of pallets can be used in different combinations, Figures 6 to 13 illustrate a method of loading a container, Figures 14 and 16 are plan views of two sizes of pallet according to an alternative embodiment, Figure 15 is a side view looking in the direction of arrow A of Figure 14, Figure 17 is a side view looking in the direction of arrow A of Figure 16, Figure 18 is an end view looking in the direction of arrow B of Figure 14 or 16, and Figure 19 is an end view looking in the direction of arrow C of Figure 14 or Figure 16. Figure 1 illustrates a loading handling pallet I according to a first embodiment of the invention. This is generally rectangular and has a width W which corresponds substantially to the internal width of a standard freight container (i.e. min. 2330 mm) with manoeuvring clearance. The length of the pallet is shown by the dimension X. The dimension X is equal to one quarter of the length of a standard 6m enclosed ISO container. Opposite lateral edges of the pallet are formed by an upstanding member 1 to provide lateral location of the pallet within the container. Member 1 is curved to form the comers 3 and has inwardly extending limbs 5 to opposite ends, each of which is secured to the edge of a box section channel member 7. Two of said box section channel members 7 are provided running in the longitudinal direction and spaced to opposite sides of the centre line of the pallet. The hollow box sections allow entry of a pair of spaced forks of a fork lift truck for lifting the pallet. The area comprising the underside of the elongate box section 7 and laterally outwardly thereof to the boundaries of the limbs 5 and lateral side members 1 provides a ground contacting support surface 9 and is infilled. The centre one third of the pallet is devoid of any ground support surface. The pallet has a load supporting cradle which in the illustrated embodiment comprises two longitudinally spaced oppositely inclined spaced apart laterally extending support surfaces 10, 11 connected by a base 12 which engages with the elongate box section elements 7. The longitudinally spaced extremities of the inclined surfaces 10, 11 are connected to respective laterally extending elongate load distribution members 13. These distribute load into the ground contacting support surfaces, divided by webs 8 and gussets 15 beneath the inclined surface and at the lateral ends which serve to reinforce same and distribute load into the ground contacting engaging surface 9 and aid weight distribution thereto. Longitudinally extending webs 14 also serve to distribute load onto the ground contacting support surfaces 9. As illustrated in outline at 19 the item to be carried is usually a cylindrical element and in the preferred application is a coil of steel sheet. The inclined surfaces will accommodate coils of different diameters. Surface 10 is covered with a sheet or discrete strips 16 of resilient material, such as high density plastics, to avoid marking of the coil and/or to act as an anticorrosion layer and to further aid weight distribution. Two securing straps shown at 21 are secured at opposite ends 21a, 21b to the cradle and arranged to pass around the circumference of the coil 19. A ratchet adjustment system is provided. In the illustrated embodiment two laterally spaced securing straps are illustrated but this is not to be viewed as limiting. In the illustrated embodiment lateral restraint of the coil is provided by lateral support legs 24. These are received releasably in a selected one of a plurality of apertures 25 in the inclined surface. The leg has a round cylindrical spigot to one end for this purpose whereby the legs 24 can be positioned in the desired lateral position. Brackets 26 provide an alternative reception location for the legs. The legs are received in this alternative location in an inverted orientation so that the spigot is uppermost. The spigot is designed to be received in an aperture in the underside of another pallet when correctly positioned on top of another to locate the two with respect to one another. There is a space 29 beneath the underside of the weight transfer lateral members 13 and the ground contacting portion of the pallet. The purpose of this will become apparent from the following description. A further adjustable load restraining strap is illustrated at 17. It is threaded through the hollow core of a coil and has its ends 17a, 17b secured to the pallet at a position within the width of the coil. It is pulled taught by a ratchet adjustment system as is well known in the art and not described further hereinafter. Where the strap changes direction it passes over curved L-shaped brackets 28 which distribute the load. This strapping also serves to prevent telescoping of the coil beyond the effect of the latest restraint legs 24. Referring now to Figure 2, this shows an alternative embodiment of load carrying pallet II which has all the same characteristics as the pallet described with reference to Figure 1 and corresponding reference numerals have been employed. The only significant difference is that the pallet is dimensioned differently in relation to the length. The width corresponds to that of the previous pallet but it is twice as long. The first embodiment is designed to carry loads of up to 10 tonnes; the second embodiment is designed to carry loads up to 25 tonnes and more specifically standard coil weights of 10 tonnes and 25 tonnes. It will be seen that the load from the coil is distributed into the ground engaging support surfaces 9 from the load receiving cradle by the above described load distribution elements. Webs 8 are increased in length to resist and distribute longitudinal forces. The pallets are preferably made of steel, although other materials may be suitable. The use of the two embodiments of pallet as illustrated in Figures 1 and 2 are described further hereinafter. Figure 3 shows a standard 6m ISO container C in which are received four of the pallets I illustrated in Figure 1. It will be seen that they are a close fit within the container and it will be apparent that the load supporting surface is positioned to distribute load into the outer one third of the floor leaving the central third of the floor clear of any load. This enables the load carrying capacity of the floor of the container to be best utilised. Figure 4 shows the same container C accommodating two of the pallets II of Figure 2, each of which is carrying a coil which can be up to 13 tonnes in weight. The two pallets occupy the floor area of the container and as such locate and restrain one another and the load thereon. Finally, Figure 5 shows the same ISO container accommodating one pallet II of the Figure 2 design and two pallets I of the Figure 1 design. In this combination the pallets I of the Figure 1 design are used to locate the other pallet II centrally within the container permitting the centre container to carry a coil of 25 tonnes weight. In an alternative configuration the centre pallet might contain a 13 tonne weight and the two outer pallets 7 tonne weights. Referring now to Figures 14 to 19, there is illustrated two sizes of pallet constructed according to an alternative embodiment. As with the previous embodiments the two sizes of pallet have the same width, which width is dimensioned to be a close fit in the width of a typical shipping container. Typically of the order of 2294 mm overall. The larger pallet of Figure 14 is substantially twice as long as the smaller pallet. Typically of the order of 2930 mm versus 1470 mm, thus permitting the same combinations of the two sizes to be fitted in a shipping container as previously described. Parts corresponding to those of the previously described embodiment utilise the same reference numerals and are not described in further detail. The pallets retain the aforementioned pair of box section channel members 7. However, the opposite lateral edges of the pallet are formed by a smaller section hollow box section 1', which is secured to the channel member 7 by a plurality of similar section hollow box section limbs 5'. Using this construction it has been found that adequate weight distribution can be achieved, whilst making considerable savings in the weight of the pallet. An open frame construction is utilised, making it possible to dispense with the previous in filling for the ground contacting support surface and with the webs 14. The load supporting cradle is substantially the same as that described previously and utilises the two longitudinally spaced oppositely inclined spaced apart laterally extending support surfaces 10, 11 connected by a base 12. Laterally extending elongate load distribution member 13 connect with the pallet foot. The comers of the pallet foot are chamfered as shown at 14. The lateral margin of the cradle is reduced in width compared with the width of the pallet foot - see a. The inclined surfaces of the cradle are provided with a plurality of strips 16' which conveniently comprise extruded rubber or synthetic equivalents, and which provide some cushioning and good frictional contact with the load. An alternative means of restraining the load in the lateral direction is employed and is described further hereinafter. It utilises a bar 150 which extends across the width of the cradle and one end carries a journal 152 by which the bar is received pivotably and laterally slidably adjustably on a tube 154 which allows it to pivot as shown by arrow X and slide in the direction represented by arrow Y. The opposite sides of the cradle carry a notched rack 156. The bar 150 carries respective lugs 158 to cooperate with respective notches of the racks 156 when the bar is in the lowered (illustrated) position. A T-bar locating element 160 (typically spring loaded) is provided to the other end of the bar to locate it in the lowered position by engaging underneath the notched bar 156 to that end of the bar 150. By means of this mechanism the two bars 150 can be positioned in close proximity to the lateral sides of the load when placed on the cradle. Strapping means is provided to further locate the coil to the pallet and comprising a first strapping element which is intended to pass through a central aperture in the coil between a lashing point 160 and an anchor point comprising a winch element 162. One or two strips may be applied over the coil from winch element 164 and passing around anchor 166. Steel loops 170 are provided to receive pulling hooks for manoeuvring the pallet on skates. Reference is now made to Figures 6 through 13 which illustrate the steps in one method by which a container C can be loaded with the above-described pallets. For the purpose of illustration two pallets II corresponding to those of Figure 2 design carrying coils of 1300 tonnes are being loaded. A standard container is shown at C in Figure 6. It comprises a standard 6m foot ISO end loading dry freight container. Figure 7 shows the positioning of elongate load handling track elements 101 within the container and braced by laterally extending brace elements 103. Load handling trolleys for use in each of the tracks is shown at 105. Such a portable track load handling system is marketed under the trade mark Joloda. The tracks are at a spacing which positions them between the elongate box section member 7. In this position the load handling trolleys 105 will engage with the underside of the member 13 so that the pallet can be raised for movement. In view of the weight to be loaded into the container it is desirable to incline the floor of the container by 3° to 5°. This can be achieved by fitting angle brackets 107 to the front corner posts and using a hydraulic jack 109 to elevate the open end of the container or by the use of blocks. Thereafter a pallet of the type II as illustrated in Figure 2 and on which a steel coil has been previously located and secured is manoeuvred by a fork lift truck 111 and deposited in the open end of the container as illustrated in Figures 8 and 9. Once in this position the load can be elevated using the hydraulic skates 107 and the load moved to the forward end of the container as shown in Figure 10. In this position the skates are lowered to allow them to be removed and the portable track removed. The open end of the container can also be lowered to the ground. A second loaded pallet II is loaded into the container using a fork lift truck as shown at Figure 12, whereafter the fully loaded container with loaded pallets/coils restrained is ready for sea shipment or otherwise. Unloading follows the reverse of the above procedure. It will be appreciated from Figures 3, 4 and 5 that alternative load configurations can be readily adopted using the two different sizes of load pallet. The pallets are configured to be stacked one on top of the other to facilitate return in a container so that it is possible to return several sets of pallets in one container.

Claims: A modular container palletisation system comprising a container (c) and a plurality of generally rectangular pallets having at least two different sizes (I, II), wherein the width of each pallet equals the internal width of the container and wherein the length of a plurality of pallets in combination equals the internal length of the container, wherein a number of said pallets are used in combination to provide pallet location and restraint within the container with the pallets occupying the full width and length of the container and with at least one pallet carrying the load, and wherein each pallet comprises oppositely disposed side members (1) serving as abutments which in use limit lateral movement within a container and further comprising ground engaging support members (1, 5, 7) extending from opposite lateral sides of the pallet and disposed spaced apart to opposite sides of a longitudinal centre line of the pallet, and comprising means for locating a load, when present, longitudinally and laterally with respect to the pallet. A modular palletisation system as claimed in claim 1, in which there are two lengths of pallet with the longer being twice as long as the shorter. A modular palletisation system as claimed in claim 1 or 2 in which two, three or four pallets occupy the length of a 6m container. A modular palletisation system as claimed in claim 1, 2 or 3 in which each pallet further comprises a load support cradle (10,11) to receive a load and distribute it to the ground engaging support members. A modular palletisation system as claimed in claim 4 in which the means for locating the load laterally comprises two legs (24, 150) which are adjustably positionable laterally to facilitate positioning in close proximity to opposite laterally sides of the load. A modular palletisation system as claimed in claims 4 or 5 in which each pallet further comprises load restraining means comprising at least one adjustable strapping member (21). A modular palletisation system as claimed in claims 4, 5 or 6 in which each pallet further comprises two laterally spaced longitudinally extending ground engaging members of hollow box section (7) and laterally outwardly thereof further ground engaging support means (1,5) in the form of a framework. A method of locating a load within a container (c) utilising a plurality of generally rectangular pallets having at least two different sizes (I, II), wherein the width of each pallet equals the internal width of the container and wherein the length of a plurality of pallets in combination equals the internal length of the container, the method comprising selecting a number of said pallets so that the width and length of the plurality of pallets in combination equals the internal width and length of the container, determining the maximum number of loaded pallets which can be accommodated in the container having regard to its weight carrying capacity, determining the proportion of container floor area which is occupied by the maximum number of loaded pallets which can be accommodated in the container, selecting the number of unloaded pallets, if any, which are required to occupy the unoccupied space, and positioning the loaded pallets and any unloaded pallets into the container in a sequence which will distribute the load most evenly over the floor of the container, providing pallet location and restraint within the container. A method as claimed in claim 8 in which the pallets are selected from pallets having equal width but two different lengths, and in which, the longer of the two lengths is twice as long as the shorter of the two lengths of pallet.

Inventors: KORDEL WOJCIECH JOSEPH, KORDEL, WOJCIECH JOSEPH
Applicants: COIL TAINER LTD, COIL-TAINER LIMITED
Application year: 1999
Main classification: B65D88
IPC codes: B65D19, B65D85, B65D90, B65D88