AU2016100306A4 - Adjustable Sleeper - Google Patents

Abstract

An adjustable sleeper is provided for mounting a portable structure. The portable structure can be of the type comprising a chassis on its underside. The adjustable sleeper can comprise a weighted sleeper body and an elongate rail associated with the sleeper body. The elongate rail can have a mounting surface onto which the portable structure can be mounted. A support system can also be associated with the weighted sleeper body and the elongate rail. The support system can be arranged to enable adjustment of the inclination of the rail relative the sleeper body. 7548127 1 (GHMailers- P102724 AlU NICOI Al Co 04)

Description

Adjustable sleeper Background Mobile or portable buildings or dwellings are often used where a temporary structure is required for shelter. The portable dwellings can be referred to as modular buildings because they can form modules which can be joined to one another to form larger structures as required. Modular structures may be used for long-term, temporary or permanent facilities, such as construction camps, schools and classrooms, civilian and military housing, and industrial facilities. Modular buildings are usually used in remote and rural areas where conventional construction may not be reasonable or possible. Once the portable building or dwelling is no longer required, it can be moved and relocated to another site. The mining industry is one industry that uses portable buildings. On mine sites, portable buildings are often positioned to form a mining camp to house workers and to provide recreational, ablution and/or sleeping areas. Once the mine has closed, the portable buildings forming the mining camp need to be removed. Typically, portable buildings are transportable by trucks and/or trains, and are often moved into and out of their in use position by a crane. Because portable buildings are not permanently fixed to a foundation, they must be anchored to the ground so that the building is not adversely affected (i.e. moved) by the weather, particularly windy weather. During periods of extreme wind, such as a cyclone, portable buildings can be blown over if the portable building is not adequately anchored to the ground. Chains and/or cables can be used to tie the portable building to an anchor. One anchor is a hulk anchor that can be buried in the ground. However, but if these anchors are not held tightly, and/or if the anchor is not suitable at high winds, then the portable building will be blown over. This situation can present a significant safety issue for any occupants sheltered in the portable building e.g. during a cyclone. Furthermore, despite removal of the portable building, the anchors are often left buried in the ground. The buried anchors can pose a hazard when later utilities companies wish to lay cables (and the like) in the area. It is to be understood that, if any prior art is referred to herein, such reference 1 7548127 1 (GHMailerse P102874 Al NICOLAL does not constitute an admission that the prior art forms a part of the common general knowledge in the art, in Australia or any other country. Summary In a first aspect the disclosure provides an adjustable sleeper for mounting a portable structure. The portable structure can be of the type comprising a chassis on its underside. The adjustable sleeper comprises: a weighted sleeper body, an elongate rail associated with the sleeper body, the elongate rail having a mounting surface onto which the portable structure can be mounted, a support system associated with the weighted sleeper body and the elongate rail and arranged to enable adjustment of the inclination of the rail relative the sleeper body. The support system can comprise at least one support member supporting the elongate rail relative to the sleeper body, the support members arranged towards respective ends of the elongate rail, wherein at least one of the support members is adapted to adjust the inclination of the elongate rail relative to the sleeper body so that the mounting surface of the elongate rail is substantially horizontal. The portable structure can be lifted up and mounted onto the mounting faces of the elongate rails, and secured into positon. The adjustable sleepers can thereby allow the portable structure to be securely mounted substantially horizontally. The adjustable sleepers can make installation of the portable structure relatively easy. The weighted sleeper body can help to ensure that the resultant portable structure is stable in e.g. high winds. Upon removal of the portable structure, the adjustable sleepers can be easily removed from the location in which they were used. In an embodiment, each of the support members supporting the elongate rail are adapted to adjust the position of the elongate rail relative to the sleeper body. Having both of the supporting members being adjustable may provide greater control over whether the mounting face of the elongate rail is substantially horizontal. When only one of the f support members is adjustable, the other support member may provide a pivot point about which the elongate rail can pivot. 2 7548127 1 (GHMalersn P102724 Al NICOI Al The support members may each comprise a device that is movable and can be fixed in a linear direction. The support members could each be a linear actuator or a hydraulic ram. In an embodiment, at least one of the support members is a screw threaded adjustable stump. Optionally at least one support member is a pair of support members, and each can comprise a screw threaded adjustable stump. In second aspect of the disclosure there is provided a system for mounting a portable structure. The portable structure can be of the type comprising a chassis on its underside. The system can comprise providing two or more adjustable sleepers in accordance with the first aspect, wherein the underside of the portable structure can be secured to each of the substantially horizontal elongate rails to mount the portable structure. In an embodiment, the weighted sleeper body comprises steel reinforced concrete. The steel used to reinforce the concrete may help to increase the weight of the sleeper body. The sleeper body may have a weight in the range of from about 1 to 4 tonnes, such as 2 to 3 tonnes. In one embodiment, the weighted sleeper body weighs at least 2 tonnes. The weight can provide ballast. The weighted sleeper body can ensure that the portable structure is securely held into positon e.g. during windy conditions. Another aspect of the disclosure provides a method of mounting a portable structure, the method comprising: providing at least one adjustable sleeper in accordance with the first aspect; optionally adjusting at least one of the support members to adjust the positon of the elongate rail relative to the sleeper body so that the mounting surface of the elongate rail is substantially horizontal; securing the portable structure to the adjustable sleeper to mount the portable structure. The step of providing the adjustable sleeper can be providing it onto pre-pre prepared ground. The pre-prepared ground/surface can comprise laying the sleeper onto a pad of earth. If after positioning the sleeper, the mounting surface of the elongate rail is not horizontal, the mounting surface can be adjusted by movement of one or both of the support members. A laser level can be used to determine whether the mounting surface is substantially horizontal. The portable structure can then be 3 7548127 1 (GHMailers P10224 AlU NICOL Al lifted and lowered into position on the elongate rail. The step of positioning the portable structure relative to the adjustable sleeper can comprise positioning the portable structure onto the mounting surface of the elongate rail. After the portable structure has been mounted, the floor (installed before or after mounting) inside the portable structure can be substantially horizontal. The step of securing the portable structure to the adjustable sleeper to mount the portable structure can comprise securing a chassis on the underside of the structure to the elongate rails. The chassis of the underside of the portable structure can be secured to the elongate rail using e.g. a clamp or a bolt. In some embodiment, the adjustable sleeper is simply used as ballast and is positioned adjacent to the portable structure. In this embodiment, adjustment of the elongate rail may not be necessary. In order to secure the adjustable sleeper to the weighted sleeper body in this embodiment, an anchor line may be attached to the portable structure and then passed through a passageway in the adjustable sleeper. The anchor line can be a chain. The step of securing the portable structure to the adjustable sleeper to mount the portable structure can comprise passing a chain from the portable structure, through a passageway formed between the weighted sleeper body and the elongate rail associated with the sleeper body and securing the chain back onto the portable structure. Alternatively, the step of securing the portable structure to the adjustable sleeper may comprise passing a chain from the portable structure, through a passageway formed in the material of the sleeper body and securing the chain back onto the portable structure. Brief description of figures Figure 1 shows an embodiment of an adjustable sleeper from a side view. Figure 2 shows a perspective view of Figure 1. Figure 3 shows a partial cross-section of an end view of a part of the adjustable sleeper. Figure 4 shows an internal frame from a side view. Figure 5 is a cross-section of A-A in Figure 4. Figure 6 is a cross-section of C-C in Figure 4. 4 7548127 1 (GHMalersn P102724 A[ NICOI Al Figure 7a is a side view of a securing means. Figure 7b is an end view of the securing means of Figure 7a. Figure 8a is a side view of a securing means. Figure 8b is an end view of the securing means of Figure 8a. Figure 9 shows two adjustable sleepers on a pre-prepared surface. Figure 10 shows a building being positioned on the two adjustable sleepers of Figure 9. Figure 11 shows an adjustable sleeper on a surface that is not horizontal. Figure 12a shows a top view of an adjustable sleeper. Figure 12b shows a top view of an adjustable sleeper. It should be understood that the line drawings in the Figures are schematics that are not drawn to scale. In some case the components may be sized and/or angled differently relative to one another than is shown in the drawings. Detailed description The structure described here in can be a mobile or portable building formed from any material including plastic and/or metal. The building can be for any use including providing shelter for people living within it, or people performing other activities within it e.g. learning or working. The type and use of the portable, mobile dwelling is not limited. The building can be modular and can be used together with other modules for form larger structures. The portable structure can be a building comprising walls defining an interior space. In some embodiments, there may be four walls defining a closed space. In some embodiments there can be an opening instead of a wall to allow access into the interior space. The dwelling can have all the usual accessories such as windows, doors, air conditioning units, electricity and other service supplied. The roof may cover the interior space and may extend over some of the walls to provide additional cover to e.g. a veranda or a porch. The roof of the mobile building can be substantially flat. The roof of the building can be pitched. If the roof is pitched, the pitch can have any angle as known in the art. In 5 7548127 1 (GHMalersn P102724 Al NICOI Al one embodiment the modular building has walls with lengths 3 m x 9 m. The modular building can be 2.4 m x 4.8 m, or 6 m x 3 m, or 9.6 m x 3 m, or 12 m x 3 m. Figure 1 shows an adjustable sleeper 10 for mounting a portable structure 12. The portable structure 12 is the type comprising a chassis 14 on its underside. The adjustable sleeper 10 has a weighted sleeper body 16 and a support system 18, 23, 20. The support system has an elongate rail, in the form of a beam or a rail 18, associated with the sleeper body 16 and onto which the portable structure 12 can be mounted. The rail 18 can be described as elongate because it extends along the sleeper body 16 longitudinally. The elongate rail 18 can have a mounting face 23. The support system can also have at least one support member 20 to support the elongate rail 18 relative to the sleeper body 16. The support members 20 can be arranged towards respective ends of the elongate rail 18. At least one of the support members 20 can be adapted to adjust the inclination of the elongate rail 18 relative to the sleeper body 16. The adjustment of the inclination can be so that the mounting face 23 of the elongate rail 18 is substantially horizontal. The adjustable sleeper 10 in Figure 2 is a perspective view of the embodiment of Figure 1, but with the portable building 12 and chassis 14 omitted for clarity. The sleeper body acts as a weight. Ideally the sleeper body 16 weighs more than 1 tonne. In an embodiment, the sleeper body 16 weighs approximately 2 tonnes. In an embodiment, the sleeper body 16 weighs more than 2 tonnes. The weight of sleeper body 16 can be determined by its size. The sleeper body 16 may have a size of approximately 3000 mm x 800 mm by 350 mm. In circumstances where the sleeper body 16 must be small, for example due to size constraints of a worksite, the weight of the sleeper body 16 may have weighted items housed within the body 12. For example, lead weights may be housed within the sleeper body 16 to increase the weight of the sleeper body. The sleeper body 16 may be made from a sufficiently heavy material. In one embodiment, the sleeper body 16 is made from concrete. The concrete may include steel reinforcement. The concrete may be extruded in accordance with relevant concrete construction regulations, for example A.S.3600. The ultimate compressive strength of the concrete may be such that concrete cylinders at 28 days must not be less than 20 MPa. The concrete may have aggregates. The aggregates may have a maximum size of 20 mm. The sleeper body 16 may be made from concrete that slumps between 50-80 mm in a slump test. 6 7548127 1 (GHMailers P10224 AlU NICOL Al The sleeper body 16 may be hollow and the internal cavity may be filled with a fluid to increase the weight of the sleeper body 16, such as water. Using a hollow sleeper body may be advantageous where transport costs are an issue, as a hollow sleeper will often be lighter compared to the hollow sleeper body filled with a weighted fluid. A sleeper body 16 that is hollow may be heavy enough to support the portable structure 12 without the need to be filled with a fluid. In such circumstances, the cavity within the sleeper body 16 may act as a reservoir, for example the cavity may house portable water or be a reservoir to review waste fluids. The elongate rail 18 may be formed from a metal. The metal may be steel. The rail 18 may have a cross-section that is square, rectangular or circular. In one embodiment, the rail 18 is hollow steel. Rectangular hollow steel and circular hollow steel may be rated to 350 MPa. Square hollow steel may be rated to 300 MPa. In the embodiment shown in Figure 1, the length of the rail 18 is shown as being less than the length of the sleeper body 16. However, in some embodiments the rail 18 may be longer than the sleeper body 16. The rail 18 may have a length corresponding to the width of the chassis 14 from the portable structure 12. In some embodiments, the length of the rail 18 is longer than the width of the chassis 14 to allow the rail 18 to support the portable structure 12 when the portable structure is being moved relative the sleeper body 16. The portable structure 12 is moved relative to the sleeper body during installation and removal. The rail 18 is shown as being substantially straight. The rail 18 can have any longitudinal shape including a zig-zag along the length of the sleeper body 16. The rail 18 can be disposed in the middle of the sleeper body 16, or it can be disposed towards one edge of the sleeper body 18. The rail 18 can be set at any angle on the sleeper body 16. For example, the rail 18 can be approximately parallel to a side 17 of the sleeper body 16 (Figure 12a), or the rail 18 is set at an angle to the side 17 (Figure 12b). When two or more adjustable sleepers 10 are used to secure a portable structure 12, the rail 18 on each adjustable sleeper 10 may each be placed on the sleeper body at different angles with respect to the side 17. The support system is able to support the rail 18 and allow adjustment of the inclination of the rail. The support system can include the rail and the at leastr one support member. The at least one support member can be a pair of support members, shown in the form of rods 20, can be adjustable to allow the rail 18 to 7 754A127 1 (H tes P102924 A[U NICOL1Al move relative the sleeper body 16. In some forms, the adjustable sleeper 10 only has one support member that can be adjusted, with the other support member simply providing an pivot point for the rail 18 to pivot about. The rods 20 can be seen more clearly in Figure 3. The rod 20 is threaded and engages with nut 26. The nut spans a top plate 28 that holds the nut 26 relative to the top of the sleeper body 16. A cavity 30 is provided in the sleeper body 16 to allow the rod 20 to retract into the cavity when the nut 26 is turned to decrease the spacing between the sleeper body 16 and the rail 18. Likewise, turning the nut 26 to increase the spacing between the sleeper body 16 and the rail 18 allows the rod 20 to extend out of the cavity 30. The size of the nut and rod may differ depending on the portable building 12 size. In an embodiment, the nut may be a M32 sized nut. The embodiment shown in Figure 3 is an adjustable stump post. Although a stump post is shown in Figure 3, other adjustable support members 20 can be used. For example, the cavity 30 may house a linear actuator or a hydraulic ram. The linear actuator or hydraulic ram may be manually operated, or they can be automatic. Automatic linear actuators or hydraulic rams may be useful to keep the rail 18 level, for example where the ground supporting the sleeper body 16 is unstable. Optionally, the support members 20 can each be rated to at least in a range of from about 30 to 50 tonnes, optionally 25 to 48 tonnes, optionally each support member is able to support at least 46 tonnes before failure. The distance that the rods 20 can be extended can be determined by the depth of the cavity 30. In an embodiment, at least one of the rods 20 can be extended by at least in the range of from about 100 to about 200 mm, optionally about 100 to about 170 mm, optionally at least one of the rods is able to move the rail over a range of at least about 150 mm. The rod 20 can be attached to a plate 32. The plate 32 can be attached to rail 18. The rod 20, plate 32 and rail 18 can be attached together by welding, although other attachment means such as rivets, screws, bolts and/or adhesives may be used. The plate 32 is shown attached to the outside of the rail, but is can alternatively be attached to the inside surface of a hollow rail. Because the rod 20 is fixed relative to the rail 18, the rods 20 may only be adjusted so that the difference in height of the rods 20a, 20b extending above the top plate 28 is less than about 50 to about 80 mm, preferably about 75 mm. If the difference in the height of the rods 8 7548127 1 (GHMailers P10224 AlU NICOL Al exceeds a threshold value (such as 75 mm) the threads on the rod 20 may start to bind with the nut 26. For example, in Figure 11, line 76 represents the height of a first rod 20a and line 78 represents the height of a second rod 20b. The difference between lines 76 and 78 should preferably be less than e.g. 75 mm. It should be noted however, that the threshold value may be dependent on the spacing between each rod 20, and that rods 20 which are spaced further apart on the sleeper body 16 may have a larger threshold value before the nut(s) 26 start to bind compared to rods 20 that are spaced closer together. For example, when the rods are spaced apart by 1.83 meters, the threshold value is approximately 75 mm. Support member rods 20 of different lengths may be needed when the sleeper body 16 is placed onto a ground 80 that is not horizontal, such as in Figure 11. During installation, if the rods start to bind before the mounting surface 23 is horizontal, the adjustable sleeper 10 may need to be temporarily removed so that surface 80 can be levelled to be more horizontal. While 75 mm height difference may be sufficient for most applications of the adjustable sleeper 10, in some circumstances for the rail 18 to be horizontal, the rods 20 may require a length difference greater than 75 mm. In these circumstances, the plate 32 may comprise upwardly extending webs (not shown) to form a C-section in which the rail 18 sits. The rail 18 can then be pivotally connected to the plate, for example with the use of a pin that passes through one side of the C-section, through the rail 18, and to the other side of the C-section. Alternatively, a resilient material, such as rubber, may be placed between the plate 32 and the rail 18 to allow movement of the plate 32 relative to the rail. When the rods 20 are fully retracted, it may be an advantage to ensure that the height of the adjustable sleeper 10, that is from the bottom surface of the sleeper body 16 to the upper surface of the rail 18, is not less a distance that is defined as a confined space. For example, in Australia, confined spaced are spaces having a height less than 540 mm, so it may be advantages to ensure that the minimum height of the adjustable sleeper 10 is greater than 540 mm, as shown by arrow 70 in Figure 9. In the embodiment shown in Figure 1, lifting points 24 are provided on the sleeper body 16. The lifting points 24 can extend upwards near the edges of the sleeper body 16. The lifting points 24 can be used by a crane to lift the adjustable sleeper 10. The lifting points 24 are shown as bent rod, but a plate having a 9 7548127 1 (GHMailers P10224 AlU NICOL Al passageway may also be used. The lifting points may be recessed into the top surface of the sleeper body 16. Passageway 22 can be located in the sleeper body 16. The passageway 22 can comprise two spaced apart passageways. The cross-sectional shape of the passageway 22, 22' can be any shape such as square. Each passageway 22, 22' can receive forks from a forklift. In one embodiment, the passageway 22, 22' are formed in the concrete and lined with square box steel. As shown in Figure 4, in embodiments where concrete is used to form the sleeper body 16, a steel frame 34 can be encased in the concrete. The frame 34 can comprise longitudinal bars 36 and ring members 38 connected the longitudinal bars 36. The lifting point 24 is a bar that has ends 40 that are engaged with the longitudinal bars 36, see for example Figure 6. The square box steel passageways 22, 22' can be connected to the longitudinal bar 36 for additional structural integrity. However, it should be appreciated that the passageway 22 does not have to be connected to reinforcement bars 36. As shown in Figures 5, the supporting members 20 can be independent of the reinforcing frame 34. Optionally, the supporting members 20 can be connected to the frame 34. The frame 34 can be made from steel. The longitudinal bars 36, ring members 38, lifting points 24 and/or support members 20 may be connected to one another by welding. When the frame 34 is encased in the concrete, the frame may act to reinforce the concrete sleeper body 16. Also shown in Figure 4 are securing means 42 for connecting or securing or affixing the chassis 14 to the rail 18. The securing means can be more clearly seen in Figures 7a-b and 8a-b. Accordingly, the sleeper body 16 and support members 20 are omitted from Figures 7a-b and 8a-b. In Figure 7a and 7b, the chassis 14 has a bottom plate 14a that rests on the mounting surface 23, 18b of rail 18. A U-shaped bolt 44 has bolts 46 that engage with an engagement plate 48. Once the chassis 14 has been positioned on the rail 18, the engagement plate 48 can slide over the bottom plate 14a. The nuts 46 can then be tightened to compress the U-shaped bolt 44 so that a bottom portion 45 of the U-shaped bolt engages with a bottom side 18a of the rail 18. Engagement plate 48 can compress the bottom plate 14a into the top, mounting surface 18b of the rail 18. The securing means 42 shown in Figure 7a-b 10 7548127 1 (GHMailers P10224 AlU NICOL Al can be a dog-clamp. Other similar clamping means may be used in place of a dog clamp, for example a C-clamp. In another embodiment, the securing means 42 can be an engagement plate 50 that sits on top of bottom plate 14a of the chassis 14. The engagement plate 50 can have strips 52a and 52b extending down the side 56a and 56b of the rail 18. A fastener, in the form of a bolt 54, can be passed through the strips 52a and 52b and the sides 56a and 56b. A nut 55 can then be screwed onto the bolt 54 to secure the plate 50 to engage the bottom plate 14a into the top surface 18b of the rail 18. Alternatively, a fastener may additionally be passed through the engagement plate 50 and the top surface 18b of the rail 18. In another form, a clamp such as a C-clamp may be placed onto the bottom plate 14a and a bottom surface of rail 18 and a camping force may be applied to secure the chassis 14 to the rail 18 (not shown). In another form, a fastener may be simply passed through bottom plate 14a into the top surface 18b of the rail 18. In another form, the chassis 14 may be secured to the rail 18 by welding and/or adhering the bottom plate 14a to the top surface 18b of the rail 18. In some forms, the chassis 14 may be secured to the rail 18 using a combination of welding and/or adhering with a securing means of Figure 7a-b or Figure 8a-b. Although the chassis 14 in the Figure is shown as being a C-rail, an I-rail or other shaped-rail having a lip can be secured to the rail 18. To mount a portable structure 12 at least one adjustable sleeper 10 is placed onto a pre-prepared surface. The pre-prepared surface can be a pad of a building site. The pad can be prepared by known methods. As shown in Figure 9, any number of adjustable sleepers can be arranged in series. In one embodiment, two adjustable sleepers 10 are placed onto a prepared surface, in the form of the area represented by the dashed lines 60. For clarity, the portable structure 12, and the details of the sleeper 10 (lifting points 24 and passageway 22) have been omitted from Figure 9. Once the sleeper have been lifted by a crane into place, one or both of the support members 20 from each adjustable sleeper 10 can be then be adjusted to ensure that the mounting surface of each rail 18 is substantially horizontal. Advantageously, each rail is adjusted so as to be substantially horizontal at the same height as the other rails, as represented by dashed lines 62. The rails 18 can be set to horizontal using, for example a laser levellers and/or individual spirit levels to ensure that they are substantially horizontal. Depending upon how horizontal the pre-prepared surface 60 is, the support members 20 may require little, if any, 11 7548127 1 (GHMailerse P102874 Al NICOLAL adjustment to ensure that the rails 18 are substantially horizontal. Once the rails 18 are substantially horizontal, a portable structure can then be moved onto the rails 18 so that the chassis 14 of the portable structure 12 is resting on the rails. Because the rails 18 span substantially the length of the sleeper body 16, the chassis 14 can be mounted by sliding it across the rails 18 until the chassis is in the correct position for securing the portable building 12 to the rail 18. In some forms, it may be advantageous to slide the portable building 12 onto the rails 18 from the side, such as shown in Figure 10. In Figure 10, the chassis 14, in the form of an I-beam, of the portable structure 12 is placed on the mounting face 23 of the rails 18 and then the portable structure 12 is slid across the mounting surface 23 in the direction of arrow 72. The portable building 12 can slide across the mounting surface 23 until the portable building 12 is in a position ready to be secured to the rails 18. In other forms, the portable building 12 is place onto the adjustable sleeper 10 by craning the portable structure 12 from above. A combination of craning and sliding the portable structure 12 may be used to position the portable structure 12 on the adjustable sleeper 10. The rails 18 may be coated with a friction reducing material to help the chassis 14 slide across the rails 18. A dog clamp or other suitable fastening means can then be used to secure the portable structure 12 to the rails of the adjustable sleeper 10 to mount the portable structure 12. Being able to use the rail, 18 to both position the portable structure 12 and secure the portable structure 12 to the adjustable sleeper 10 may save time and simplify installation of the portable structure 12 on site. To remove the portable structure 12 from the adjustable sleeper 10, the fastening means 42 can be removed, and the portable structure 12 can then be removed from the adjustable sleeper 10. The adjustable sleepers 10 can then be removed, for example by using a crane by lifting from lifting points 24, or by using a fork lift to lift using passageway 22. Although only two adjustable sleepers 10 are described, more than two adjustable sleepers 10 can be used to secure the portable structure 12. The number of adjustable sleepers 10 used to secure the portable building can be determined by the structure type and where the structure is being secured. For example, in areas that are more likely to encounter windy conditions such as a cyclone, three or more adjustable sleepers 10 can be used. For example, if each adjustable sleeper weights 12 7548127 1 (GHMailers P10224 AlU NICOL Al approximately 2 tonnes and a portable structure 12 requires approximately 8 tonnes of anchoring weight, 4 adjustable sleepers 10 can be used to secure the portable structure 12. When a plurality of adjustable sleepers 10 are used to secure a portable structure, some of the adjustable sleepers 10 may be secured together, for example with a chain passing through the adjacent passageway 22. Additionally, in circumstances where addition weight needs to be added to secure the portable structure 12, one or more adjustable sleepers 10 may be placed at one or more sides of the portable structure 12 and chains and/or cables may be looped through the lifting points 24 and/or passageway 22 to secure the building. In some embodiment, the adjustable sleeper 10 is simply used as ballast and is positioned adjacent to the portable structure. In this embodiment, adjustment of the elongate rail 18 may not be necessary. In order to secure the portable structure 12 to the weighted sleeper body in this embodiment, an anchor line may be attached to the portable structure and then passed through the passageway 22, 22'. The anchor line can be a chain. The step of securing the portable structure to the adjustable sleeper to mount the portable structure can comprise passing a chain from the portable structure, through a passageway formed between the weighted sleeper body and the elongate rail associated with the sleeper body and securing the chain back onto the portable structure. Alternatively, the step of securing the portable structure to the adjustable sleeper may comprise passing a chain from the portable structure, through a passageway formed in the material of the sleeper body and securing the chain back onto the portable structure. It will be understood to persons skilled in the art of the invention that many modifications may be made without departing from the spirit and scope of the invention. In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention. 13 7548127 1 (GHMailers P10224 AlU NICOl Al

Claims (5)

1. An adjustable sleeper for mounting a portable structure, the adjustable sleeper comprising: a weighted sleeper body; an elongate rail associated with the sleeper body, the elongate rail having a mounting surface onto which the portable structure can be mounted, a support system associated with the weighted sleeper body and the elongate rail and arranged to enable adjustment of the inclination of the elongate rail relative the sleeper body.

2. The adjustable sleeper according to claim 1, wherein the support system comprises at least one support member supporting the elongate rail relative to the sleeper body, the support members arranged towards respective ends of the elongate rail, wherein at least one of the support members is adapted to adjust the inclination of the elongate rail relative to the sleeper body so that the mounting surface of the elongate rail is substantially horizontal.

3. The adjustable sleeper of claim 1 or 2, wherein each of the support members supporting the elongate rail are adapted to adjust the position of the elongate rail relative to the sleeper body, and wherein at least one of the support members is a screw threaded adjustable stump.

4. A system for mounting a portable structure, the system comprising two or more adjustable sleepers in accordance with any one of claims 1 to 3; wherein the underside of the portable structure can be secured to each of the substantially horizontal elongate rails to mount the portable structure.

5. A method of mounting a portable structure, the method comprising: providing at least one adjustable sleeper in accordance with any one of claims 1 to 3; optionally adjusting at least one of the support members to adjust the positon of the elongate rail relative to the sleeper body so that the mounting surface of the elongate rail is substantially horizontal positioning the portable structure relative to the adjustable sleeper; and securing the portable structure to the adjustable sleeper to mount the portable structure. 14 7548127 1 (GHMailers- P102724 A[U NICOI Al