Hollow box section integrated lifting point

Abstract

A hollwo box setion beam comprises top and bottom walls and spaced parallel side walls. The beam has a longitudinal centreline axis extending along its length. The beam incorporates an extrusion or bu

Description

FIELD OF THE INVENTION The present invention relates to a novel lifting apparatus and related methods for use with a hollow box section beam. The hollow box section may be part of a structure inside a modular container. The invention relates to an integrated lifting point, which is located within a hollow box section beam. The hollow box section may have a rectangular cross sectional area, or it may have a square cross sectional area. BACKGROUND OF THE INVENTION Water treatment is a process which is required in many countries throughout the world to make water clean enough to drink. Water treatment systems are typically made up of various stages, such as flocculation, sedimentation, filtration, disinfection, and storage. It is possible to contain water treatment devices within a shipping container-shaped unit. These units may be modular, and may be designed to be connected to one another. The units may be formed of beams which are oriented horizontally, and columns which are oriented vertically. The beams and columns are connected together to form the structure of the building. The units may be made from structural steel sections which are in the form of hollow box section beams. The hollow box section beams may have a square or rectangular cross sectional area. Hollow box section is used as an alternative to I beams or universal beams. Throughout this specification, hollow box section beams will be referred to as any generic four sided box section shaped beam. Hollow box section beams are not as common as their universal beam counterparts. However box section beams have some advantages over universal beams. Hollow box section beams have higher torsional stability and higher strength to weight ratio than universal beams for example. This is particularly advantageous when twisting or high stress loads are anticipated. Hollow box section beams can also be considered to be more aesthetically pleasing than other beam types. However, one disadvantage with hollow box sections is that there is no currently easy way of lifting them. If the building which is made from hollow box needs to be lifted, then lifting points on the beams is a desirable feature. This makes lifting the building much easier. Existing solutions in the art include lifting eyes, which are generally welded onto the tops of the hollow box sections. These types of lifting points can be problematic as they protrude high above the top wall of the beam when in use. They are also permanently fixed on, and thus can be considered to be a permanent obstruction. There are no solutions in the art which integrate a lifting point into a hollow box section. Integrating a lifting point into a hollow box section is not an easy task, as there is no obvious place to put a lifting point into a hollow box section. Furthermore, the width associated with the hollow box section prohibits using standard shackles. The hollow box section needs to maintain structural integrity to continue to function as a beam. The hollow section beams can be used to form a structural skeleton, which can then be clad with any suitable material to form a strong, lightweight, waterproof, movable container which can contain any type of water treatment devices. The movable units can be modular in form, such that they can be stacked on top of one another, and be joined together side-to-side. To move the modular units, there is a requirement to lift them for transport onto a articulated trailer for example. Lifting points are typically added to allow lifting of the module, usually with the aid of a lifting or a spreader frame. The lifting points typically consist of plate steel, profiled or cut into a specific shape, then welded into a permanent location or welded onto a bolted base. The lifting points allow a shackle to be connected to them. These pad-eyes may be welded onto the top of hollow box section beams at suitable lifting point locations. Alternatively, pad-eyes are welded onto suitable base plates, and the base plates are bolted onto the tops of the hollow section beams. However both of these methods have downsides. Firstly, if the pad eye is welded onto a base plate and is bolted onto the existing hollow box section beam, then the hollow box section beam needs to be drilled. The bolted connection also requires installation on site, and would require correctly torqued bolts: both of which are time consuming tasks. This is therefore not a desirable solution. If the pad eye is welded onto the top of the hollow box section beam, this also requires additional labour to attach. Furthermore, the welded section on the top wall of the box section may be weakened by the heat from the welded portion. In addition, the overall height of the container will be increased, which due to transportation limits will result in the container being reduced in size (otherwise road transport rules will be broken). There is therefore a need for a solution which is less time consuming, and one which reduces the amount of work required on-site. There is also a need for a solution which provides a strong, low-profile, lifting point for use with a modular unit made from a hollow box section beam structure. There is also a need for a component which is integral to a universal beam, such that load testing can be done within a workshop environment, and not on-site. SUMMARY OF THE INVENTION According to a first aspect of the present invention there is provided a hollow box section beam comprising: a top wall, a bottom wall, and two side walls; a beam longitudinal centreline axis which extends along the length of the hollow box section beam; an extrusion which extends from one side wall to the other side wall, wherein the extrusion comprises a through-hole which is parallel to the top wall and the bottom wall, wherein the extrusion comprises an extrusion centreline axis; wherein the extrusion centreline axis is located between the beam longitudinal centreline axis and the top wall, wherein the extrusion and through-hole provide an integrated lifting point for use with a bow shackle. The extrusion centreline axis is generally arranged perpendicular to the beam longitudinal centreline axis. The extrusion may be cylindrical. The extrusion may be any suitable shape to house a through-hole which is suitable for use with a bow shackle. The through-hole may be concentric with the cylindrical extrusion. The through-hole may be eccentric with the extrusion. The through-hole may be located anywhere on the extrusion, which is suitable for attaching a bow shackle to. The outer diameter of the cylindrical extrusion may be at least double the diameter of the through-hole. The cylindrical extrusion may protrude above the top wall of the box section beam. The extrusion centreline axis may be located at the midpoint between the beam longitudinal centreline axis and the top wall. The hollow box section beam may comprise reinforcing plates attached to the side walls and / or the top wall to further strengthen the integrated lifting point. The reinforcing plates may be of any suitable shape or orientation. The reinforcing plates may be cuboidal. The reinforcing plates may be welded onto the hollow box section. The reinforcing plates may be used to brace the cut out in the top of the top wall, to provide reinforcing strength. The extrusion may extend to be flush with the side wall reinforcing plates. The extrusion may be of any suitable length to be strong enough to withstand the forces in a pin shackle. The extrusion may only extend to be flush with the side walls. The beam, the extrusion, and the reinforcing plates may be made of steel. The beam, the extrusion, and the reinforcing plates may be made from any other suitable material which is strong enough to withstand the forces of a lifting point. The top wall reinforcing plate may be 15mm thick, and the side wall reinforcing plates may be 10mm thick. The top wall reinforcing plate may be any suitable thickness to reinforce the top wall. The side wall reinforcing plates may be any suitable thickness to provide a bracing force to the side walls. The hollow box section beam may have a square cross section. The hollow box section beam may have any four sided shape cross section. The beam may be made from 5mm thick steel. The beam may be made from any thickness of material. In another example, there is provided a method for forming a hollow box section beam according to any beam which has been previously described, the method comprising the steps of: providing a hollow box section beam; drilling a hole through each of the side walls to accommodate an extrusion; slotting the extrusion through the drilled hole into location; fixing the extrusion into place via welding. There may be additional minor steps to the method process, such as preparing the materials for drilling and welding. The method may further comprise the step of fixing the reinforcing plates into place via welding. BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the present invention will now be described, by way of example only, with reference to the following figures: Figure 1 is an example of an integrated lifting point according to the invention, shown integrated into a hollow box section beam; Figure 2 shows an elevation view of the integrated lifting point according to the invention; Figure 3 shows a plan view of the integrated lifting point which is shown in Figure 2; Figure 4A is an elevation view of the cross section BB (from Figure 2) and Figure 4B is a perspective view of the cross section BB; and Figure 5 is an elevation view of a container comprising four integrated lifting points. DETAILED DESCRIPTION Generally speaking, the present invention relates to an integrating lifting point for a box section beam. Figure 1 is an example of an integrated lifting point 100 according to the invention, shown integrated into a hollow box section beam 102. In this particular example, the hollow box section beam 102 has a square cross section. Figure 1 is a cut away of a portion of a hollow box section beam 102, which is used as a hollow member from a building. Below the hollow box section beam 102 is a corrugated sheet of metal, which would act as a wall for the building. The hollow box section beam 102 comprises a top wall 110, a bottom wall 111, and two side walls 112. The hollow box section beam comprises a beam longitudinal centreline axis 114, which extends along the length of the beam. An extrusion 104 extends from one side wall 112 to the other side wall 112. The extrusion 104 comprises a through-hole which is parallel to the top wall 110 and the bottom wall 111. The extrusion 104 also comprises an extrusion centreline axis 116. In this example, the through-hole is concentric with the extrusion longitudinal centreline axis 116. The through-hole extends completely from one side wall 112 to the other side wall 112. In this particular embodiment, the extrusion centreline axis 116 is located between the beam longitudinal centreline axis 114 and the top wall 110. The extrusion centreline axis 116 and the beam longitudinal centreline axis are arranged generally perpendicular to each other. In use, the extrusion 104 and the through-hole provide an integrated lifting point 100 for use with a bow shackle. The lifting point 100 is used to lift the beam. The beam is typically arranged in a horizontal manner as part of a building structure. The integrated lifting point 100 provides a secure robust feature for attaching a bow shackle to. The pin-type connection allows for a pin to be inserted into the through-hole, and allows the pin to rotate freely. This prevents any unwanted forces from being transferred into the beam structure such as bending or twisting. In this embodiment of the invention, the extrusion 104 is cylindrical. The outer diameter of the cylindrical extrusion 104 as shown is around double the diameter of the through-hole. This wall thickness ensures a very strong extrusion, and ensures the safety of the integrated lifting point. However, other ratios of wall thickness of the extrusion are also possible. In addition, the location of the extrusion combined with the wall thickness of the extrusion 104, results in a portion of the extrusion 104 protruding above and through the top wall 110 of the beam 100. This is an design choice as part of the invention. The design intent of having a protrusion out of the top wall 110 is to allow for a bow shackle to be used which can easily reach the through-hole. If the extrusion 104 was centred on the beam longitudinal centreline axis 114, which is the obvious location for such a feature (if the designer had considered an extrusion), then the bow shackle would need to have greater reach and clearance to reach the through-hole. Furthermore, if the designer did not want to breach the walls of the hollow box section beam 102, then they would have needed to reduce the wall thickness of the extrusion 104. This would therefore limit the maximum lifting capability of the integrated lifting point 100. If the designer did consider to increase the thickness of the extrusion, and the extrusion was located in the midpoint between the top wall 110 and the bottom wall, then they would naturally breach both the bottom and the top walls 110 of the hollow box section 102. This however would seriously impair the strength of the hollow box section 102, and would render the beam 102 unsuitable for lifting. The designers of the present invention have therefore carefully chosen the extrusion and the through-hole to be located above the centreline axis, such that if the extrusion is of a wide enough diameter, then it only breaches the top wall 110 of the beam 102. There is also a significant reducing in manufacturing effort if only the top wall 110 is breached. Hollow box section beams 102 can withstand a breach in the top wall 110, and still be strong enough for continued use. If additional strengthening is required, then reinforcing plates can be added to the beam 102. Top wall reinforcing plates 108 can be added to the top wall 110, and side wall reinforcing plates 106 can be added to the side walls 112. The reinforcing plates 106 / 108 can be made from any suitable material such as steel. They can completely cover the width of walls or they may only partially cover them. The reinforcing plates 106 / 108 can also extend the whole length of the beam 102, or they may only extend partially along the beam length (as shown in Figures 1 and 2). The size of the hollow box section beam shown is 100mm x 100mm x 5mm. The side wall reinforcing plates 106 are 10mm thick, and the top wall reinforcing plates are 15mm thick. The extrusion 104 is 120mm long, and has a diameter of 120mm. The centre line 116 of the extrusion 104 is located at the midpoint between the top wall 110 and the beam longitudinal centreline axis 114. The extrusion 104 has a through-hole which has a diameter of 52mm. Therefore in this example, the extrusion 104 extends longitudinally to be flush with the side wall reinforcing plates 106. Figure 2 shows an elevation view of the integrated lifting point 100 shown in Figure 1, and Figure 3 shows a plan view of the integrated lifting point which is shown in Figure 2. The elevation view in Figure 2 clearly shows that the extrusion centreline axis 116 is located above the beam longitudinal centreline axis 114. The extrusion centreline axis 116 may be located anywhere between the beam longitudinal centreline axis 114 and the top wall 110. The plan view in Figure 3 shows clearly where the reinforcement plates 106 / 108 are located on the hollow box section beam 104. Figure 4A is an elevation view of the cross section BB (from Figure 2) and Figure 4B is a perspective view of the cross section BB. The extrusion centreline axis 116 can be clearly seen running through the centreline axis of the extrusion 104. The wall thickness of the extrusion 104 can also clearly be seen from Figures 4A and 4B. Figure 5 is an elevation view of a container 200 comprising four integrated lifting points 100. The four integrated lifting points 100 in the container 200 are shown being lifted by a lifting apparatus 300. A typical lifting apparatus 300 comprises flexible chains or straps which are orientated generally vertically, and a ridged spreader bar which is located between the chains or straps, and is generally horizontally oriented. The integrated lifting points 100 according to the invention therefore allow a container building 200 such as that shown to be safely lifted and transported, whilst maintaining the structural integrity of the container 200. Whilst specific embodiments of the present invention have been described above, it will be appreciated that departures from the described embodiments may still fall within the scope of the present invention.

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