The present invention relates to an equipment handling system. Equipment for use on an offshore platform such as an oil rig is usually transported in a shipping container. However, conventional shipping containers are not suited to transportation of heavy equipment. Heavy equipment may be loaded into a shipping container using a forklift truck, but conventional forklift trucks are not permitted on offshore platforms and thus cannot be used to remove the heavy equipment from the shipping container when it arrives at the offshore platform.

There is no straightforward way of removing heavy equipment from a shipping container on an offshore platform. Manual handling of the heavy equipment may sometimes be used, but such manual handling is often inappropriate and commonly leads to injury. An alternative approach is to use a crane on the offshore platform to drag the heavy equipment out of the shipping container. However, cranes on offshore platforms are designed to provide vertical lifting and are not suited to pulling equipment from a shipping container. As a result, attempting to use a crane in this manner is hazardous and liable to fail, potentially with the risk of injury to operators.

Since there is no straightforward way of removing heavy equipment from a shipping container on an offshore platform, it is common to ship heavy equipment on a pallet with an open top instead of in a shipping container. However, shipping heavy equipment on a pallet with an open top suffers from the disadvantage that the equipment is exposed to the elements during shipping. In addition, if a wooden pallet is used then it must be treated before shipping in order to prevent possible infestation on the offshore platform.

It is an object of the invention to address or mitigate a problem associated with transportation of heavy equipment.

According to a first aspect of the invention there is provided an equipment handling system comprising a pallet provided with air casters, a shipping container with a floor arranged to support air casters, and a support structure with a surface arranged to support air casters, the support structure being configured to be received at an entrance of the shipping container such that the support structure surface and the shipping container floor meet to form a continuous air caster supporting surface.

The system allows the pallet and equipment to be moved out of the container onto the support structure on a cushion of air provided by the air casters. The cushion of air may be considered to be a boundary layer of air. Movement of the equipment and pallet is easily achieved without operators being required to lift them. Thus, injuries caused by operators lifting heavy equipment are avoided. The support structure may comprise a pair of elongate structures, each elongate structure having a surface arranged to support air casters.

Each elongate structure may comprise a track which is configured to guide the air casters of the pallet.

Sides of the track may be defined by lips which run along sides of the elongate structure.

A wall or the roof of the shipping container may be provided with brackets configured to receive one or more of the elongate structures.

The elongate structures may be beams.

One or more holes may be provided at the end of the support structure.

The system may further comprise a locking mechanism configured to secure the support structure to the entrance of the shipping container. The locking mechanism may be at an opposite end of the elongate structure from the one or more holes. The pallet may be provided with a recess which runs along the length of the pallet.

The shipping container floor may be provided with a ridge which is configured to be received in the recess in the pallet. The pallet may comprise a plurality of pallet modules connected together, each pallet module being provided with at least four air casters.

An air caster may be provided adjacent to each corner of each pallet module. The pallet may comprise two pallet modules connected together along one side.

Each pallet module may have an air conduit which supplies air to the air casters. The air conduits of each pallet module may be connected to each other when the pallet modules are connected together.

Protective barriers may extend partway up side walls of the shipping container from the floor of the shipping container.

According to a second aspect of the invention there is provided a pallet comprising a plurality of pallet modules connected together, each pallet module being provided with at least four air casters.

An air caster may be provided adjacent to each corner of each pallet module. The pallet may comprise two pallet modules connected together along one side.

Each pallet module may have an air conduit which supplies air to the air casters. The air conduits of each pallet module may be connected to each other when the pallet modules are connected together.

Embodiments of the invention will now be described by way of example only, with reference to the accompanying figures, in which:

Figure 1 is a perspective view of an equipment handling system according to an embodiment of the invention;

Figure 2 is a schematic cross-sectional view of the equipment handling system shown in figure 1 ;

Figure 3 is a schematic cross-sectional view of an air caster of the equipment handling system ;

Figure 4 is a schematic cross-sectional view of part of the equipment handling system; and

Figure 5 is a schematic view from below of a pallet of the equipment handling system.

Figure 1 shows in perspective view an equipment handling system 1 comprising a pallet 2 provided with air casters 3, a shipping container 4 and beams 6 (which may also be referred to as outriggers). The shipping container 4 has a floor 5 arranged to support the air casters, and the beams 6 are provided with upper surfaces 7 arranged to support air casters. The height of the air caster supporting surface 7 of a beam corresponds with the height of the floor 5 of the shipping container 4. The beams 6 are positioned such that the upper surfaces 7 of the beams meet the floor 5 of the shipping container, and thereby provide a continuous air caster supporting surface along which the pallet 2 may be moved.

Figure 2 is a cross-sectional view of the shipping container 4 with the pallet 2 positioned in situ. Equipment schematically indicated by a box 8 is supported by the pallet 2. A recess 1 1 is provided at the centre of the pallet 2 and extends along the length of the pallet. The recess 1 1 is dimensioned to receive a ridge 12 which projects from the container floor 5. The ridge 12 extends along the length of the container 4. The recess 1 1 and ridge 12 cooperate to prevent significant sideways movement of the pallet 2 within the container 4 and thus act as a guide for the pallet 2 as it is being moved out of the container 4.

Protective barriers 14 extend partway up side walls of the container 4 from the floor 5. The protective barriers 14 prevent accidental impact of the pallet 2 against walls of the container 4 during movement of the pallet (e.g. during loading of the pallet into the shipping container using a forklift truck).

The pallet 2 is provided with an air inlet port 16 through which pressurised air may be delivered into the pallet. Conduits within the pallet 2 connect the air inlet port 16 to each of the air casters 3. Thus, when pressurised air is supplied through the air inlet port 16, the pressurised air is delivered to the air casters 3 and thereby energises the air casters. Pressurised air supplies are widely available on offshore platforms. The air inlet port may be dimensioned to receive a hose (not shown) which provides pressurised air from an offshore platform pressurised air source. The pallet 2 is provided with openings 13 which are dimensioned to receive prongs of a forklift truck. This allows the pallet 2 and the equipment 8 to be moved using a forklift truck when onshore. Thus, easy loading of the pallet 2 into the container 4 is possible onshore. The protective barriers 14 may help to guide an operator of an forklift truck to keep the pallet 2 central within the container 4, such that the ridge 12 will be received in the recess 1 1 when the pallet is lowered by the forklift.

The ridge 12 and the protective barriers 14 may be secured to the container 4 using bolts which are screwed into threaded holes, for example provided in the floor 5 of the container. The ridge 12 and protective barriers 14 are thus easily removable, thereby allowing the container 4 to be returned to being a conventional container. The threaded holes may be capped when the ridge 12 and protective barriers 14 are not present. In figure 2 the beams 6 are attached to walls of the container 4 using brackets 18. This is advantageous because it provides for transport of the beams 6 together with the pallet 2 and equipment 8 in the container 4. In an alternative embodiment, instead of having the brackets on walls of the container 4 the brackets may be fixed to the roof of the container (extending downwardly from the roof). Because the brackets 18 are on the walls or extend down from the roof of the container 4 they occupy space that is not needed for equipment 8 to be transported by the container. The beams 6 may be slid into and out of the brackets 18 by an operator at the door of the container. This is advantageous because it avoids for example an operator being required to stand inside the container 4 and lift the beams 6 over the equipment 8. The term "bracket" is not intended to imply a particular shape, but instead is intended to generally describe a structure which is configured to receive and hold a beam. In an alternative arrangement (not depicted) the beams may be attached to doors of the container.

In an embodiment, the beams 6 may be transported separately, or may be already present on an offshore platform such that transportation of beams in the container 4 is not required.

Figure 3 shows the air caster 3 (which may also be referred to as an air bearing) schematically in cross-section. The air caster 3 comprises a housing 30 which includes a base 31 , a perimeter wall 32 and a central protrusion 33. The housing 30 may, for example, be metal. A flexible membrane 35 extends between the perimeter wall 32 and the central protrusion 33. The flexible membrane 35 may, for example, be formed from rubber. The air caster 3 is held in a recess in the pallet 2. An air conduit 36 in the air caster 3 connects with an air conduit 17 in the pallet 2. The air conduit 36 extends to an air outlet 38 provided at the end of the central protrusion 33. Branch conduits 40 extend through sides of the central protrusion 33 to outlets which are configured to deliver air to a cavity located between the flexible membrane 35 and the base 31 .

The air caster 3 is energized in Figure 3, i.e. pressurized air is being provided to the air caster via the air conduit 17 of the pallet 2. The pressurized air which passes out of the branch conduits 40 pushes the flexible membrane 35 outwards such that it forms a generally flat surface (bending upwards where the flexible membrane connects to the housing 30). Pressurized air which passes out of the outlet 38 in the central protrusion 33, passes between the flexible membrane 35 and the floor 5 and then passes out from underneath the perimeter wall 32. The pressurized air flowing between the flexible membrane 35 and the floor 5 provides an air cushion which supports the air caster 3. Since the housing 30 is no longer in contact with the floor 5, there is no friction between the housing and the floor, and instead the air cushion provides an almost frictionless interface between the air caster 3 and floor 5. Since friction has been substantially eliminated, movement of the pallet 2 when supported by the air casters 3 may be achieved using very small amounts of force (compared with the force that would be required if the pallet 2 was not supported by an air cushion).

When the air caster 3 is not energized, the flexible membrane 35 is no longer pushed outwards and there is no flow of air beneath the flexible membrane. Consequently, the housing 30 rests upon the floor 5 of the container. The flexible membrane 35 is accommodated in the space between the base 31 and the floor 5.

The perimeter wall 32 may be, square, rectangular, circular or some other suitable shape. The membrane 35 may include openings which allow some air to bleed through the membrane 35. The central protrusion may have a configuration which differs from that shown in Figure 3. In general, the air caster may have any suitable form. Figure 4 shows in cross-section the pallet 2 supported on the beams 6 via the air casters 3. In Figure 4 the pallet 2 has been moved out of the container 4 and is supported entirely on the beams 6. As may be seen, the beams 6 include lips 20 which extend along sides of the beams. The lips 20 form a track 21 within which the air casters 3 are received, and along which the air casters are guided. The track 21 has a generally U-shaped cross-sectional profile. The lips 20 prevent significant sideways movement of the pallet 2 when it is being moved out of the container 4.

The beams 6 may, for example, be made from metal or plastic. The beams 6 should be sufficient strong to support the anticipated weight of the equipment 8 which will be transported using the pallet 2.

Operation of the equipment handling system will now be described with reference to Figures 1 to 4. The equipment 8 is placed onto the pallet 2 when the pallet 2 is not located within the shipping container 4. The pallet 2 may, for example, be in an onshore warehouse where the equipment 8 is stored. Once the equipment 8 has been lifted onto the pallet 2 (e.g. using a crane) the pallet 2 is lifted using a forklift truck and is transported to the container 4. The forklift is used to insert the pallet 2 into the container 4, with some guidance being provided by the barriers 14. The pallet 2 is lowered by the forklift such that housings 30 of the air casters 3 rest upon the floor 5 of the container 4. The forklift is then removed from the pallet 2. If needed, beams 6 are secured to the brackets 18 mounted on the walls of the container 4 (this may be done before or after the pallet 2 and equipment 8 have been loaded into the container). The pallet 2 and equipment 8 are secured to the container 4 in a conventional manner. Doors of the container 4 are then closed, following which the container 4 is shipped to an offshore platform.

The container 4 is transferred to the offshore platform, for example using a crane. The doors of the container 4 are then opened and the beams 6 are removed from the brackets 18 and positioned as shown in Figure 1 . That is, the beams 6 are pushed up against the container 4 such that an air caster supporting surface of each beam adjoins the floor 5 of the container 4. In this way a continuous air caster supporting surface which extends from within the container to the beams 6 is provided. A locking mechanism (not shown) may be used to secure each beam 6 to the container 4. The locking mechanism may for example comprise an arm which extends outwards and then downwards from the beam 6, and which is received in a slot in the floor of the container 4.

A source of compressed air on the offshore platform is connected via a hose to the air inlet port 16. This supplies air to the air casters 3 via the conduit 17 such that the air casters are energized and support the pallet 2 on an air cushion. The pallet 2 is then pulled out of the container 4 either by pulling the pallet directly or by pulling the equipment 8. The pallet 2 is guided by the ridge 12 engaged in the recess 1 1 , such that significant sideways movement of the pallet cannot occur. This ensures that the pallet remains aligned relative to the container 4 as the container is moved out of the container. By ensuring that the pallet 2 can move in only one linear direction, the ridge 12 and recess 1 1 ensure that the pallet moves in a predictable manner and thereby avoid the possibility of an operator being injured by unexpected sideways movement of the pallet.

As the pallet 2 moves out of the container 4 the air casters 3 transition from being supported by the floor 5 of the container to being supported by the beams 6. A continuous air caster supporting surface is provided at the point where the container floor 5 meets each beam 6, such that the air casters 3 continue to operate normally and support the pallet 2 as they pass across the join between the floor and the beam. In other words, the join does not provide a leakage path which would allow enough air to escape from an air caster 3 that the air cushion provided by the air caster collapses and ceases to support the pallet (if this were to happen then it would be likely to prevent further movement of the pallet).

As the pallet 2 is moved out of the container 4 the air casters 3 are guided by tracks 21 formed by the lips 20 of the beams 6. The lips 20 prevent significant sideways movement of the pallet 2. Thus, the pallet 2 continues to be constrained to move only in a longitudinal direction. That is, the pallet can only move further out of the container 4 or be pushed back into the container and cannot move to a significant degree in other directions. As noted above, by restricting movement of the pallet 2 to a linear and predicable direction, injuries caused by unexpected movements of the pallet in other directions are avoided. Once the pallet 2 has been moved fully out of the container 4 the supply of compressed air to the air casters 3 is stopped. Since compressed air is no longer being supplied, the air casters 3 no longer provide an air cushion and the pallet 2 rests upon the housings 30 of the air casters. Further movement of the pallet 2 will now not take place. A crane may then be used to hoist the equipment 8 from the pallet 2, and the equipment may be moved by the crane to its desired location.

The supply of compressed air source is then resumed to provide compressed air to the air casters 3. The air casters 3 once again provide an air cushion which supports the pallet 2, allowing the pallet 2 to be pushed back into the container 4. The compressed air is then stopped, and the hose which supplies the compressed air is removed from the air inlet port 16. The beams 6 are secured to the brackets 18 inside the container 4 (if the beams are not to remain on the offshore platform) and the doors of the container are then closed. The container is then shipped back onshore and used to transport other equipment.

At any point during use, the supply of compressed air provided to the pallet 2 may be stopped in order to stop movement of the pallet. This may be done, for example, if continued movement of the pallet is liable to cause an accident. Because the air casters 3 lift the pallet 2 and equipment 8 on a cushion of air, movement of the equipment and pallet is easily achieved without operators being required to lift them. The substantially frictionless cushion of air provided by the air casters 3 allows the equipment 8 and pallet 2 to be moved easily out of the container 4. Thus, injuries caused by operators lifting heavy equipment are avoided.

At least one of the beams 6 may be provided with one or more holes (not depicted) at one end (e.g. the opposite end from the locking mechanism). When the air caster 3 is located over the holes air will pass through the holes, thereby collapsing the air cushion of the air caster and preventing the air caster from moving beyond the holes. Since the holes are located at one end of the beam (the distal end of the beam in use) the pallet 2 is able to travel along the beam 6 until an air caster 3 overlaps with the holes. When the air caster 3 overlaps with the holes it collapses, and this prevents the pallet from travelling beyond the end of the beam 6. Holes may be provided in both beams 6. In an alternative arrangement a lip (not depicted) may be provided at the end of at least one beam 5. The lip is configured to stop the air caster 3 and thus prevents the pallet from travelling beyond the end of the beam 6. A lip may be provided on both beams.

Figure 5 shows the pallet 2 viewed from underneath. The pallet 2 is provided as two separate pallet modules 2a, 2b which are secured together using a locking arrangement. The locking arrangement (not depicted) may for example comprise a peg which extends from one pallet module 2a through a hole into the other pallet module 2b and is secured in place (e.g. using a split pin). When the pallet 2 is formed from two pallet modules 2a, 2b as shown in Figure 5, the pallet has eight air casters 3, an air caster being provided adjacent to each corner of each pallet module. Four of the air casters 3 are located adjacent to the join at which the pallet modules 2a, 2b are connected together. Thus, these four air casters 3 are provided relatively close together (i.e. with a separation which is less than the separation between air casters at opposite ends of a pallet module). A central region of the pallet 2 therefore has more air casters 3 than other regions of the pallet. Each air caster 3 is capable of safely supporting a particular weight. Providing more air casters 3 at a central region of the pallet 2 is advantageous because it allows a heavier weight to be safely supported at a central region of the pallet (the heaviest part of heavy equipment will typically be located at the centre of that equipment).

In an embodiment, a pallet which is a single pallet module 2a (or 2b) may be used to transport equipment. A single pallet module may be used for example to transport equipment with a relatively small footprint (e.g. a footprint which is smaller than the pallet module and thus does not require two pallet modules for transportation). Where this is the case a correspondingly smaller shipping container may be used.

In an embodiment, a pallet may be formed from three or more pallet modules connected together. A dotted line in Figure 5 indicates the conduit 17 which carries compressed air through the pallet 2 from the air inlet port 16 to each of the air casters 3. As may be seen, the conduit 17 followed by the compressed air passes through a join between the pallet modules 2a, 2b. In order to achieve this, an air outlet port and an air inlet port may be provided in the pallet modules 2a, 2b, with an O-ring and corresponding groove (or other sealing arrangement) being used to provide a seal at the connection between the pallet modules. A plug 34 is provided at an opposite end of the air channel 30 from the air inlet port 16. The plug 34 may for example be threaded and received in a correspondingly threaded opening. Although Figure 4 shows the track 21 which guides the air casters 3 as being formed from lips 20 on both sides of each beam 6, the track may have any suitable form. In an embodiment, the track may be formed from lips provided only on inner edges of the beams. This will still constrain movement of the pallet 2 such that the pallet cannot move a significant amount in a sideways direction. In an alternative embodiment the track may be formed from lips provided only on outer edges of the beams 6. Again, this will constrain movement of the pallet 2 such that the pallet cannot move a significant amount in a sideways direction. In both of these embodiments there is a risk that an air caster 3 may fall off a beam 6 if it is not aligned correctly with respect to shipping container (this risk is avoided when lips 20 are provided along both sides of each beam 6).

The beams 6 are examples of elongate structures suitable for supporting an air caster. Any suitable elongate structures may be used. The air caster supporting surfaces of the elongate structures may have a height which corresponds with the height of the floor of the container. The elongate structures may be generally linear. The elongate structures may be provided with tracks which guides the air casters.

Other suitable support structures may be used instead of elongate structures. A support structure which is a single entity may be used. A support structure which provides a single caster supporting surface may be used. Where this is the case, lips may be provided on the caster supporting surface in a manner which corresponds with that shown in Figure 4 in order to prevent significant sideways movement of the pallet 2. Alternatively, lips may be provided only along outer edges of the path along which the pallet is to travel, or only along inner edges of the path along which the pallet is to travel. Alternatively, or additionally, a ridge may be provided on the support structure which generally corresponds with the ridge 12 on the container floor 5 shown in Figure 2.

In an embodiment, a support structure may comprise elongate structures such as beams secured together using a frame or other means. An advantage of such an arrangement is that it ensures that the beams are always parallel to each other and reduces the likelihood that one of the beams is not properly aligned with the container.

Embodiments of the invention do not use any electrical equipment, but instead only use compressed air. Electrical equipment may be hazardous on an offshore platform due to the potential presence of flammable gases. The invention avoids this potential hazard.