Cover for providing a floor structure over an opening

Abstract

A cover for providing a floor structure over an opening. The cover includes first and second elongate side members 106a, 106b, a beam 1 extending between the elongate side members 106a, 106b, and firs

Description

BACKGROUND OF THE INVENTION This invention relates to a cover, and to a method of manufacturing a cover. The cover is suitable for providing a floor structure over an opening (i.e. for covering an opening), for example for covering a swimming pool. It is desirable to be able to place a cover over a swimming pool or other opening when it is not in use. It is important for safety purposes, to reduce the risk of accidental drowning due to a person or animal falling into the water of a full swimming pool or other body of water unexpectedly, and possibly also to reduce the risk of injury due to a person or animal falling into an empty swimming pool or other opening. In many countries there are safety restrictions which require the covering of swimming pools when not in use. A cover is also desirable in order to prevent dirt and debris from accumulating within the swimming pool, either in the empty recess or in the water if the swimming pool is full. It is known to provide flexible, floating swimming pool covers which may be slid or unrolled onto a swimming pool to cover it. These can be inconvenient to deploy and retract and since they are flexible most of them cannot safely be walked on, and therefore the area of the swimming pool is unusable when the swimming pool is covered. It is known, as an alternative, to provide rigid swimming pool covers, which retain their shape and are selectively slid either into a position covering the swimming pool or are slid away. Such covers are advantageous since they provide a usable deck area which can be used whether the cover is slid over the pool or off the pool, meaning that the area above the pool is usable for other activities (e.g. as a dining or play area) when the swimming pool is covered. However, known arrangements are often very bulky because significant vertical load must be carried by the beam, which is inconvenient for users, particularly since for a longer span they create a large step up which must be taken in order to step onto the usable area of the cover, and moreover they are often very heavy and therefore difficult for users to move between the covering position and the retracted position. Similar issues also arise with covers intended to cover other kinds of openings and provide a floor structure over them. The present invention seeks to provide a cover for providing a floor structure over an opening which addresses at least some of these shortcomings. SUMMARY OF THE INVENTION From a first aspect, the invention provides a cover for providing a floor structure over an opening, the cover comprising: a first elongate side member; a second elongate side member; a beam extending between the first elongate side member and the second elongate side member; a first length of elastic suspension member, connected between a first sidemember contact point, on the first elongate side member, and a first beam contact point on the beam, so as to (i.e. such as to, the connection arranged to) apply a tensile force to (i.e. induce a tensile stress in) the first length of elastic suspension member; and a second length of elastic suspension member, connected between a second side-member contact point, on the second elongate side member, and a second beam contact point on the beam, so as to apply a tensile force to the second length of elastic suspension member; wherein the tensile force in (i.e. through, transmitted along) the first length of elastic suspension member and the second length of elastic suspension member provides a force to at least the first beam contact point and the second beam contact point, so as to provide a supporting force to the beam which acts against (i.e. in opposition to) a load force produced by a load placed, in use, on the beam. Thus it will be seen that, in accordance with the invention, by connecting first and second lengths of elastic suspension member to the beam, and placing these in tension, they provide, in use, a supporting force to the beam, acting against a load force produced by a load placed on the beam (i.e. so as to be load-bearing lengths of suspension member). Thus they provide, in use, an upwards supporting force acting in response to a downwards force due to gravity acting on a weight placed on a top of the beam, i.e. when acting as a floor structure. It will be understood that the beam is intended, in use, to span over an opening. This upwards force acts on at least a portion of the beam (i.e. at least at the first and second beam contact points). As a result, the beam itself doesn’t need to be as strong, and it can therefore have a smaller cross-section than if no load bearing member(s) are provided. In particular, the height of the beam (i.e. the distance it extends upwards, in a direction perpendicular to the plane of an opening covered, in use, by the cover) is reduced compared to if no elastic suspension members are used. This is beneficial for customers since the cover is less obstructive when its height is reduced, and it is easier for customers to use (e.g. as a deck or patio space) since the height of a step up that a user must make to be stood on the cover is lower than would otherwise be the case. It also reduces the overall weight of the cover, which makes the cover easier for a user to move. Furthermore, the cost may also be lower for such a cover since less beam material is needed (due to the reduced cross-section), and even though there is additional cost for the elastic suspension member(s) and associated parts, this may be much less than the saving made due to reduced beam material, giving a cost saving overall. These advantages are particularly significant for large covers (e.g. more than 4 metres by 8 metres, optionally more than 5 metres by 10 metres), particularly if the beam is intended to span the larger dimension of the opening (e.g. swimming pool) (depending on the particular layout), since the beams needed to provide support for the cover over such a large opening are particularly large, thus creating a particularly high and obstructive step, and a heavy cover. A floor structure will be understood as a load-bearing surface on which a person or people may safely stand and on which objects, such a furniture, may be safely placed. Thus the cover is deployable over an opening such that it covers over the opening and provides a structure over the opening (e.g. void) on which people may safely stand or walk and on which furniture may be placed. The cover is thus a load-bearing cover, able to withstand a load greater than simply its own weight, optionally at least double its own weight. The lengths of suspension member are referred to as elastic. By this it will be understood that the suspension member (i.e. the material forming the suspension member) is resiliently deformable, i.e. able to be deformed from its normal or neutral length without breaking, and able to then spontaneously resume its normal or neutral shape, such that deformation (e.g. stretching) from its normal shape (e.g. length) is resisted by a restoring force, such that the suspension member(s) are able to withstand an applied tensile stress. It will be appreciated that deformation of the elastic suspension member(s) by application of a tensile force (or forces) induces deformation which stores potential energy in the elastic suspension member(s) as elastic strain energy, and causes it to produce a restoring force at the first and second beam contact points. In some embodiments, the modulus of elasticity of the elastic suspension member(s) (e.g. of the first length and / or the second length) (i.e. of the material of the elastic suspension member(s)) may be at least 50 GPa, optionally at least 100 GPa, further optionally at least 150 GPa, further optionally at least (or approximately) 200 GPa. It will be appreciated that in order to provide a supporting force which acts against a (downwards) load force produced by a load placed on the beam in use, the lengths of elastic suspension member must be connected to the respective (first or second elongate side members) at a higher position then where they connect to the beam, such that a component of the force produced due to the tensile force in the length(s) of suspension member will act vertically upwards. In some embodiments, the second elongate side member extends parallel to the first elongate side member, defining a cover plane. Each elongate side member may extend perpendicular to the beam (optionally to more than one beam, further optionally to all the beams, where multiple beams are present). The upward direction and the downwards direction will be understood as extending in mutually opposite directions perpendicular to the cover plane, i.e. with the upwards direction being understood as the direction which extends, in use, away from the opening (e.g. the opening in the ground defining an upper surface of a swimming pool), and the downwards direction extending, in use, towards the opening that is covered. Thus the supporting force provides a force (i.e. has at least a component) in a direction perpendicular to the cover plane (i.e. upwards). It will be appreciated that in order to provide this supporting force the side-member contact points cannot be level with the beam contact points (since otherwise they could only provide horizontal force). Thus, in some embodiments, the first sidemember contact point is located at a first height relative to the direction perpendicular to the cover plane, and the first beam contact point is located at a second height relative to the direction perpendicular to the cover plane, wherein the first height is greater than the second height (i.e. further along the upwards direction). Similarly, in some embodiments, the second side-member contact point is located at a third height relative to the direction perpendicular to the cover plane, and the second beam contact point is located at a fourth height relative to the direction perpendicular to the cover plane, wherein the third height is greater than the fourth height (i.e. further along the upwards direction). The first height and the third height may be the same and / or the second height and the fourth height may be the same. This advantageously gives a symmetrical arrangement, which produces a more symmetrical supporting force in the beam. Height will be understood as referring to the distance along that particular distance, but not as suggesting that the referenced points are co-axial along that particular direction. In some embodiments, the first length of suspension member is arranged to contact the beam at a (first) secondary beam contact point, wherein the tensile force in the first length of elastic suspension member provides a force to the secondary beam contact point, so as to provide a supporting force to the beam which acts against a load force produced by a load placed, in use, on the beam (i.e. the first length of suspension member contacts the secondary beam contact point in such a manner as to apply a vertically upwards force on the beam). The first length of suspension member may thus provide upwards force at multiple contact points on the beam, allowing a particularly desirable force to be achieved. It may of course also contact the beam at other contacts points in a manner which does not impart such a force. The secondary beam contact point may be located between the first beam contact point and the first side-member contact point, along the length of the beam (i.e. along the length direction, horizontally). The secondary beam contact point may be located at a height (i.e. relative to the direction perpendicular to the length of the beam or to the cover plane, in the vertical direction) which is between the first height, of the first side-member contact point and the second height, of the first beam contact point. The same features may likewise apply to the second length of elastic suspension member. Thus, in some embodiments, the second length of suspension member is arranged to contact the beam at a second secondary beam contact point, wherein the tensile force in the second length of elastic suspension member provides a force to the second secondary beam contact point, so as to provide a supporting force to the beam which acts against a load force produced by a load placed, in use, on the beam. The second secondary beam contact point may be located between the second beam contact point and the second side-member contact point, along the length of the beam (i.e. along the length direction, horizontally). The second secondary beam contact point may be located at a height (i.e. relative to the direction perpendicular to the length of the beam or to the cover plane, in the vertical direction) which is between the third height, of the second side-member contact point and the fourth height, of the second beam contact point. The first secondary beam contact point and the second secondary beam contact point may be positioned at the same height. The first secondary beam contact point and / or the second secondary beam contact point may be provided by a protrusion or sheave. In some embodiments, the first beam contact point and / or the second beam contact point are located towards a lower edge of the beam (e.g. in the lower half, optionally in the lower third, further optionally in the lower quarter). Lower will be understood as referring to the part which is lower, in use, along the vertical direction (i.e. lower along the height direction, e.g. perpendicular to the cover plane, described above). The first beam contact point and / or the second beam contact point may be positioned level with or above a lower edge of the first elongate side member and / or the second elongate site member. Thus, the first beam contact point and / or the second beam contact point (i.e. the second height and / or the fourth height) may be within the height of the first and second elongate side members. In some embodiments, the first side-member contact point is located towards an upper edge of the first elongate side member (e.g. in the upper half, optionally in the upper third, further optionally in the upper quarter). The first side-member contact point may be located at an upper edge of the first elongate side member. Similarly, in some embodiments, the second side-member contact point is located towards an upper edge of the second elongate side member (e.g. in the upper half, optionally in the upper third, further optionally in the upper quarter). The second side-member contact point may be located at an upper edge of the second elongate side member. In some embodiments the first side-member contact point is positioned level with or below an upper edge of the beam. Similarly, in some embodiments, the second side-member contact point is positioned level with or below an upper edge of the beam. The first side-member contact point and / or the second-side member contact point may be within the height of the beam (i.e. rather than above or below it). The beam may be substantially level with (i.e. extending between, but not substantially above or below) the first elongate side member and the second elongate side member. The beam is therefore not suspended from a position located above the beam, but rather from a contact point within the vertical span of the beam (i.e. the height of the beam), but connecting to a higher point than the point at which the suspension member connects to the beam. The first length of elastic suspension member is connected between a first sidemember contact point on the first elongate side member and a first beam contact point on the beam, and similarly the second length of elastic suspension member is connected between a second side-member contact point on the second elongate side member and a second beam contact point on the beam. By this it will be understood that there is a connection between the respective length of suspension member and the respective points on the side members and the beam, but that this connection may be direct or indirect (i.e. the suspension member being connected to an intermediate component which itself is connected to the beam or side member). Furthermore it will be understood that the connection(s) need not necessarily be fixed connections. For example, one or more connection(s) may be a sliding connection, e.g. such that the suspension member extends around a roller or slides within a groove. In some embodiments, the first length of elastic suspension member is fixedly connected to the first side-member contact point. In other embodiments, the first length of elastic suspension member is movably connected to the first side-member contact point (e.g. in sliding connection with the first side-member contact point). In some embodiments, the second length of elastic suspension member may be fixedly connected to the second side-member contact point. In other embodiments, the second length of elastic suspension member is movably connected to the second side-member contact point. The cover may be a cover for covering a swimming pool (i.e. a swimming pool cover). Thus, there is provided a swimming pool cover, comprising a cover as described herein above and further below). By this it will be understood that the cover is suitable for covering a recess in a structure (e.g. the ground) within which fluid (e.g. water) may be placed for the purpose of bathing or swimming (e.g. for leisure). For example, it may be sized so as to cover a swimming pool. The (upper) opening of the recess may define a recess plane, wherein, in use, the cover plane is arranged substantially parallel to the recess plane. The cover may be (substantially) rigid, e.g. non-foldable. As described below, the cover may further comprise an outer covering (e.g. so as to provide a closed cover), however the cover need not necessarily be fully closed, e.g. it may comprise only the side members and the support members. This may allow a user to later provide an outer covering to the claimed cover structure. The invention further extends to a swimming pool system, comprising a swimming pool and further comprising a cover as described herein above, and in further detail below, the cover selectively deployable to cover the swimming pool so as to provide a floor structure over the swimming pool. In some embodiments a (single) elastic suspension member provides both the first length of elastic suspension member and the second length of elastic suspension member. Thus the cover may comprise a suspension member, providing both the first length and the second length. Thus, in some embodiments, a (single) elastic suspension member extends continuously between the first side-member contact point on the first side member and the second side-member contact point on the second elongate side member (i.e. and contacts the beam at both the first beam contact point and the second beam contact point). The extension of the elastic suspension member continuously from one side member to the other side member is advantageous since it provides improved force distribution, by providing a continuous length through which horizontal forces are balanced, since the horizontal component acting on each end of the central connecting part of the suspension member (between the beam contact points) is equal in magnitude from each of the first and second length and opposite directions so that it is balanced in that central section. Thus, in some embodiments, the first length of suspension member and the second length of suspension member may be connected by a first connecting length of elastic suspension member (i.e. they may be part of the same suspension member). The first connecting length of elastic suspension member may contact the beam along substantially along all of its length. In some embodiments, the cover further comprises a third length of elastic suspension member, connected between a third side-member contact point, on the first elongate side member, and a third beam contact point on the beam; and a fourth length of elastic suspension member, connected between a fourth side-member contact point, on the second elongate side member, and a fourth beam contact point on the beam; wherein the tensile force in the third length of elastic suspension member and the fourth length of elastic suspension member provides a force to at least the third beam contact point and the fourth beam contact point, so as to provide a supporting force to the beam which acts against a load force produced by a load placed, in use, on the beam. The provision of an additional suspension member (or members) is advantageous since the forces that each individual suspension member must withstand are lowered by sharing out the load. In some embodiments a (single) elastic suspension member provides both the third length of elastic suspension member and the fourth length of elastic suspension member. Thus the third length and fourth length of elastic suspension member may be connected by a second connecting length of elastic suspension member. This provides the same advantages as described above with respect to the first and second lengths. A first suspension member may provide the first and second lengths of suspension member and a second (separate) suspension member may provide the third and fourth lengths of suspension member (e.g. each with outer ends attached to the respective side members). Any of the features described above with respect to the first and second lengths may apply equally to the third and fourth lengths. In some embodiments a (single) elastic suspension member provides the first, second, third and fourth lengths of elastic suspension member (e.g. by looping the suspension member at the first side-member contact point (to also provide the third side-member contact point) and / or at the second side-member contact point (to also provide the fourth side-member contact point). Thus in some embodiments, a single looped elastic suspension member provides the first, second, third and fourth lengths of elastic suspension member. In some instances the partially or fully looped suspension member may be able to be tensioned more easily than using two separate suspension members, and need to be fixed in place in fewer locations along their length. The elastic suspension member(s) (i.e. the first length of elastic suspension member, and / or the second length of elastic suspension member and / or the third length of elastic suspension member and / or the fourth length of elastic suspension member) may be elongate (i.e. long and thin). The suspension member(s) may be (substantially) cylindrical. The suspension member(s) (e.g. the first length and / or the second length) may have a diameter or width (i.e. in a direction perpendicular to its length) of less than 20mm, optionally less than 10mm, further optionally less than 8mm, optionally of approximately 6mm. The first length and / or the second length may have a length of at least 2m, optionally at least 3m, further optionally at least 4m. The elastic suspension member(s) may be wire(s), e.g. metal wire. The elastic suspension member(s), or lengths, may all be made of the same material. The (first or second length of) elastic suspension member(s) may comprise (or be formed from or consist of) steel, for example galvanised steel or stainless steel. This is particularly advantageous since it provides a suitable amount of both strength and elasticity to act as a load bearing suspension member in the described arrangement. In some embodiments, the first beam contact point and the second beam contact point are separated along the length of the beam (where the length is defined along the direction extending between the side members). This similarly applies to the third and fourth beam contact points, where present. The first and third beam contact points may be positioned at the same length along the beam (i.e. in the horizontal direction), and the second and fourth beam contact points may be positioned at the same length along the beam (i.e. in the horizontal direction). This is advantageous since if both are connected to the same point then the beam is effectively (in terms of forces) divided into just two beams, and each of these will have to be sufficiently strong to withstand the maximum bending moment of a beam of that length. In contrast, if the beam contact points are separated, then the beam is effectively (in terms of considering forces produced by a load supported by the beam) split into three lengths, which allows each beam to be shorter, and therefore reduces the maximum bending load each section must withstand. In some embodiments, the first beam contact point and the second beam contact point are (approximately) equidistant from each other and from the first side-member contact point and the second-side member contact point, along the length of the beam (i.e. relative to its length axis, e.g. along the horizontal direction, in use, as set out above they are not all on the same axis). In terms of forces, this effectively divides the beam into three sections of (approximately) equal length, thereby minimising the length of each section and therefore minimising the maximum bending moment which each section, and therefore the overall beam, must be dimensioned to withstand. Thus, in such an embodiment, the central section is the same length as two side sections, each located on opposite sides of the central section (i.e. between the central section and the respective side members). In some embodiments, the first side-member contact point and / or the second sidemember contact point comprises a clamp, arranged to engage the respective first length of elastic suspension member or second length of elastic suspension member. Thus the suspension member(s) may first be tensioned (e.g. using a suitable ratchet or screw or other tensioning device), and then fixed place in the clamp to maintain this tension in the suspension member(s). The contact point(s) (or clamp(s)) may be located on an inner side of the respective side member(s) (i.e. the side closer to the beam), or may alternatively be located on an outer side of the respective side members). Location on the outside provides easier access for tensioning, but also exposes the contact point or clamp to the weather when in use. In some embodiments, the supporting force (i.e. provided by the first and second lengths of elastic suspension member) may be at least 600 N, optionally at least 800N, further optionally at least (or approximately) 1200N. Thus, the supporting force provided by the first length of suspension member (or the second length of suspension member) may be at least 300 N, optionally at least 400 N, further optionally at least (or approximately) 600 N. The second suspension member (or third and fourth suspension member lengths) may apply the same force, thus doubling the total supporting force. In order to achieve these supporting forces, the tensile stress applied through the first length and / or the second length of suspension member (or the first suspension member where one suspension member provides both lengths) may be at least 5000N, optionally at least 10000N, further optionally at least 15000N. The tensile stress applied through the first length and / or the second length of suspension member (or the first suspension member where one suspension member provides both lengths) may be less than 40000N, optionally less than 30000N, further optionally less than 12000N. It will be appreciated that selecting the magnitude of the tensile force applied to the first and second lengths of elastic suspension member affects the amount of load which the floor structure is capable of supporting, since it affects the magnitude of the upwards force that the suspension members provide to the beam. The magnitude of the tensile force(s) may therefore be selected based on the (maximum) load which the floor structure is intended (i.e. desired) to support. In some embodiments, the tensile force may be arranged to cause a central portion of the beam to be raised up in the absence of an external load acting downwards on the beam. Thus, when no additional load is placed on the floor structure provided by the cover the beam will be raised up (i.e. curved up) in its central section compared to its outer sections. This slightly upwards curve in the centre prevents water from accumulating on the cover since instead it will run downwards from the raised central point towards the outer edges of the beams, and ideally off the cover. In some embodiments, a central section of the beam, extending between the first beam contact point and the second beam contact point, is reinforced (i.e. relative to the other portions of the beam, not positioned between the first beam contact point and the second beam contact point). This advantageously may provide additional strength to the central section which may need to withstand a larger bending moment, and the central section may also be formed or shaped so as to facilitate easy and convenient connection of the suspension member(s) at the first beam contact point and the second beam contact point. Thus, in some embodiments, the beam comprises a primary section (or portion), extending between the first elongate side member and the second elongate side member, and further comprises a secondary section, attached to the primary section. The secondary section may provide the first beam contact point and the second beam contact point. The secondary section may be connected to a central part (i.e. portion, section) of the primary section. The first beam contact point may be a first (e.g. lower) corner of the secondary section. The second beam contact point may be a second (e.g. lower) corner of the secondary section. Thus the secondary section may provide the reinforcement referenced above, i.e. it may be a reinforcement section. The beam (e.g. the secondary section) may comprise one or more grooves to accommodate a suspension member. The groove(s) may be located in a lower portion of the beam (e.g. the secondary section), i.e. in the part located, in use, closer to the opening that is covered. The first connecting length of elastic suspension member and / or the second connecting length of elastic suspension member (as referenced above) may be accommodated within a groove (e.g. both in a groove or respectively in a first and a second groove). The groove may be elongate, and may extend along (i.e. parallel to) the length of the beam. In some embodiments, the beam comprises (or consists of or is formed from) aluminium. It is common for supporting beams more generally to be made of steel, due to its higher strength, however steel is much denser and therefore weighs much more, and is also often more expensive (stainless steel is generally more expensive than aluminium). Using aluminium for the beam therefore allows a lighter beam to be provided which is still capable of withstanding the loads needed in order for the floor structure to be used as desired. In some embodiments, the first elongate side member and / or the second elongate side member are also provided by beams. These beams may have different profiles to the beam referenced above (i.e. the supporting beam which extends between them) or they may all have the same profile. They may comprise aluminium. The cover may be deployable to cover the opening, i.e. movable into a covering position. The cover may be arranged in sliding contact with the surface in which the opening is defined (e.g. with the ground). The elongate side members are thus supported from below (e.g. by the ground), and in turn support the outer edges of the beam(s) which are in contact with them. In some embodiments, the cover further comprises one or more wheels or castors. The cover may comprise at least a first wheel or castor, connected to the first elongate side member and a second wheel or castor, connected to the second elongate side member. This allows the cover to be slid into position covering an opening (e.g. a swimming pool), and moved away to allow access to the opening (e.g. to the swimming pool). The wheels or castors may be arranged to run along tracks. The invention further extends to a cover system (e.g. a swimming pool cover system), comprising the cover as described herein above, further comprising one or more wheels or castors as described, and further comprising one or more tracks along which the wheel(s) or castor(s) are arranged to slide, to enable movement of the cover between a covering position, covering an opening (e.g. a swimming pool), and a retracted position, allowing access to the opening (e.g. the swimming pool). It will be understood that the beam extends continuously between the first elongate side member and the second elongate side member. The cover may further comprise one or more additional beams, extending between the first elongate side member and the second elongate side member (i.e. extending parallel to the beam referenced above, in a different position along the length of the side members). Said beams may have any of the features described above with reference to the (first) beam. These provide a greater supported area, and therefore a larger cover, suitable for covering a larger opening. The separation of adjacent beams along the length direction of the cover (i.e. perpendicular to the beam, parallel with the elongate side members) may be less than 2 metres, optionally less than 1 metre, further optionally less than 50 cm, further optionally less than 30 cm. The separation of the beams along that direction may be selected based on the load that it is desired for the cover to support, in use (i.e. the beams may be placed closer together in order for the cover to support a greater load). The first elongate side member and / or the second elongate side member may be at least 2m long, optionally at least 4m long, further optionally at least 6m long. The beam may be at least 2m long, optionally at least 4m long, further optionally at least 6m long, further optionally at least 8m long. The beam may have a height (perpendicular to its length direction i.e. along the vertical direction, in use) of less than 400mm, optionally less than 300 mm, further optionally less than (or approximately) 200 mm. In some embodiments, the cover is rectangular (i.e. defining a length direction and a (perpendicular) width direction). The cover may extend further along the length direction than along the width direction. The beam may extend along (i.e. parallel to) the width direction or along the length direction. The cover may extend at least 2m along the length direction, optionally at least 4m, further optionally at least 6m. The cover may extend 2m along the width direction, optionally at least 4m, further optionally at least 6m, further optionally at least 8m. In some embodiments, the cover further comprises an upper (or outer) covering, arranged to be positioned, in use, on the beam and to extend between the first elongate side member and the second elongate side member so as to cover the beam. The upper covering may extend between adjacent beams (optionally across all the beams), e.g. to provide a solid surface to the cover, on which a user may safely stand, walk, and place furniture. In some embodiments the cover further comprises one or more side coverings, arranged to be positioned, in use, to cover the first side member and / or the second side member (and / or a side surface of the outer beams, at each outer edge of the cover). A method of manufacturing a cover for providing a floor structure over an opening, the method comprising: extending a beam between a first elongate side member and a second elongate side member; connecting a first length of elastic suspension member between a first side-member contact point, on the first elongate side member, and a first beam contact point on the beam, so as to apply a tensile force to the first length of elastic suspension member; and connecting a second length of elastic suspension member between a second side-member contact point, on the second elongate side member, and a second beam contact point on the beam, so as to apply a tensile force to the second length of elastic suspension member; wherein the tensile force in the first length of elastic suspension member and the second length of elastic suspension member provides a force to at least the first beam contact point and the second beam contact point, so as to provide a supporting force to the beam which acts against a load force produced by a load placed, in use, on the beam. The method may comprise steps of carrying out or forming any of the features described above in relation to the cover. It will be understood that connecting each length of elastic suspension member between the respective side-member contact point and beam contact point may comprise separate stages of connecting the suspension member to the beam and to the side-member, or these stages may be carried out together, i.e. at the same time or stage. It is stated that the suspension member lengths are connected so as to apply a tensile force to the respective suspension members. It will be understood that this connecting may be the initial connection between the suspension members and the respective contact points (i.e. such that the tension is introduced when they are initially connected together), or this step may comprise altering the connection between the suspension member and one or more of the contact points. For example, the suspension members) may initially be connected in the claimed manner but in the absence of any tension. The suspension member may then have an external tensile force applied to it, and may then be fixed (e.g. clamped) in its stretched configuration to keep this tensile force on it. In this case the connection at the clamp point (which may be one or more of the side-member contact points) is changed in order that the claimed tensile force is applied. This will be understood as connecting a first length of elastic suspension member between a first side-member contact point, on the first elongate side member, and a first beam contact point on the beam, so as to apply a tensile force to the first length of elastic suspension member. In some embodiments, the method further comprises tensioning the first length of suspension member and / or the second length of suspension member (optionally a first suspension member and / or a second suspension member) using an external tensioning device, e.g. a ratchet or screw tensioning device. The method may comprise selecting a magnitude of the tensile force applied to the first length of suspension member and / or the second length of suspension member based on the (maximum) load which the floor structure is intended (i.e. desired) to support. It will be appreciated that, unless otherwise stated, the method steps may be carried out in any order and need not necessarily be carried out in the order in which they are listed. Features of any aspect or embodiment described herein may, wherever appropriate, be applied to any other aspect or embodiment described herein. Where reference is made to different embodiments or sets of embodiments, it should be understood that these are not necessarily distinct but may overlap. BRIEF DESCRIPTION OF THE DRAWINGS Certain preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a schematic diagram showing a perspective view of a swimming pool cover according to an embodiment of the present invention; Figure 2 is a perspective view showing certain components of the swimming pool cover of Figure 1; Figure 3 is a side view showing certain components of the swimming pool cover of Figure 1, in particular showing a wheel engaged with a track; Figure 4 is a cross-sectional side view of an alternative attachment mechanism for a wheel; Figure 5 is a perspective view showing a cutaway view of a central section of a beam and showing the elongate side members of the swimming pool cover of Figure 1; Figure 6 is a schematic diagram representing the distribution of load, and the corresponding bending moments, for a beam extending over an opening and supported on two support points, as is known in the prior art; Figure 7 is a schematic diagram representing the distribution of load, and the corresponding bending moments, for a beam according to the present invention; Figure 8 is a perspective view showing certain components of the swimming pool cover of Figure 1, in particular showing certain lengths of suspension member and showing the second and fourth side-member connection points; Figure 9 is a perspective view showing an external end portion of a swimming pool cover according to a second embodiment of the present invention; Figure 10 is a cutaway view showing the same perspective as Figure 9, with the primary section removed so that the suspension member and the secondary portion of the beam are more easily visible; Figure 11 is a cross-sectional view of the beam taken in its central section, along the line A indicated in Figure 7; Figure 12 is a schematic diagram representing a beam and associated components of a cover according to a third embodiment of the invention; and Figure 13 is a flow diagram representing a method according to the present invention. DETAILED DESCRIPTION Throughout the figures, like reference numerals have been used for like elements. An example cover 100, according to an embodiment of the present invention, is illustrated in Figure 1. In this particular example, the cover is intended to cover a swimming pool 101, although it will be appreciated that in other examples other types of openings may be covered. The swimming pool cover 100 is intended to selectively cover the swimming pool 101, by moving the swimming pool cover 100 to either be over the pool 100 (covering it) or to be retracted to a position in which the pool is uncovered. The term swimming pool 101 will be understood to refer to the recess in both the empty and the full state, where in the full state the recess is filled with water and is suitable for use for swimming. For ease of movement the swimming pool cover 100 is provided with wheels 102 along both sides which are arranged to roll along elongate parallel tracks 104 so as to move the swimming pool cover back and forth, covering or uncovering the swimming pool 101. The swimming pool cover 100 has a rigid top surface 108, and also rigid side surfaces 110. The swimming pool cover 100 includes a support structure, described in further detail below with reference to Figures 3-11, which enables the swimming pool cover 100 to provide a floor structure which is capable of supporting substantial loads, meaning it can be safely stood on and walked on and also used as a deck or patio area whilst covering the swimming pool. To achieve this, a support structure as shown in Figure 2 is provided, which includes elongate side members 106a, 106b which extend along the movement direction of the swimming pool cover 100. The weight of these is directly supported on the wheels 102, i.e. the side members are located, in use, directly above ground (rather than the swimming pool void). To provide support above the swimming pool 101, beams 1 are provided which extend, in use, over the pool (in the covering position) between the two side members. This structure is described in further detail below. The swimming pool cover 101 has a width 112 (in the direction across the pool opening to be covered, i.e. parallel to the beams) and a length 114 along its movement direction. It also has a height 116, i.e. in the direction perpendicular to the swimming pool 101. The height 116 of the cover is largely determined by the height of the beams 1 required to span the swimming pool 101 in order to support the pool cover 100. It is desirable that this height be minimized so that the pool cover 100 does not create a step which is uncomfortably high for a user. It is therefore advantageous that the pool cover according to the present invention allows the height of the beam required to withstand the necessary loads on the pool cover 100 to be reduced, as described further below. Figure 3 is a side view showing an end-on view of the swimming pool cover 100 of Figure 1. In this view a wheel 102 is visible, which is grooved so as to engage with a protrusion from the track 104. The wheel 102 is supported by a structure provided by the first elongate side member 106a. In this view an end covering panel 110a and a side covering panel 110b, providing two of the side surfaces, are also visible. Figure 4 is a cross-sectional view of a slight variation of the arrangement of Figure 3. In this example the shape of the wheel engaging part 118 is slightly more curved and less angular than in the other arrangement, but otherwise the parts are the same. In the cross-sectional view of Figure 4 a lip 120 on the side member 106a is visible. This lip is also present, though not visible, in the example of Figure 3 (and is seen in other Figures which show this embodiment). The beams 1 sit on this lip 120, and a corresponding lip on the other side member 106b, and these provide the outer support points for the beams 1 and support their weight. Figure 5 is a perspective view in which details of one of the beams 1, extending between the two side members 106a, 106b, and associated components, are visible in more detail. In this view, only a central section 6 of the beam 1 is shown, although in reality the beam 1 extends all the way across from the first elongate side member 106a to the second elongate side member 106b. As a result of the outer parts of the beam 1 being cutaway, to more clearly show the suspension members which are described below, the end covering panel 110a, which provides a rigid end surface of the cover 100, is visible. The side parts of the beam 1, between the central section 6 and the two elongate side members, are likewise missing in Figures 8-10, and are there represented by dashed lines 19. The side parts of the beam 1 are visible in the view of Figure 2. The pool cover 100 also includes a first suspension member 4 and a second suspension member 5. The first suspension member 4 extends from the first elongate side member 106a to the second elongate side member 106b, and in its central part it contacts the central section 6 of the beam 1. The second suspension member 5 likewise extends between the first elongate side member 106a and the second elongate side member 106b, contacting the beam 1 in its central section 6. Thus, each suspension member 4,5 includes a first length 4a, 5a which extends from a respective side-member contact point 8a, 9a on the first elongate side member 106a, to a respective first beam contact point 10a, 11a on the central section 6 of the beam 1. Each suspension member 4, 5 also includes a second length 4b, 5b which extends from a respective side-member contact point 8b, 9b on the second elongate side member 106b, to a respective second beam contact point 10b, 11b on the central section 6 of the beam 1. For each suspension member a third, connecting length 4c, 5c (visible in Figures 7 and 11), extends between the first length 4a, 5a and the second length 4b, 5b, within the central section 6, as described further below and as seen in Figure 11. These connecting lengths advantageously transfer horizontal force due to the tension in the suspension members 4, 5, and thereby avoid creating a high stress point on the central section 6 of the beam 1. However, it will be understood that in some examples the connecting lengths need not be present, and instead separate suspension member lengths may be connected on each side to the central section of the beam. The side-member contact points 8a, 9a, 8b 9b are provided by clamps in this example. This allows the suspension members 4, 5 to be pulled to create a desired amount of tension through the suspension members, and then fixed in place in these clamps 8a, 9a, 8b 9b. This tensile force which acts along the suspension members 4, 5 provides a force to at least the first beam contact points 10a, 11a and the second beam contact points 10b, 11b, so as to provide a supporting force to the beam which acts against (i.e. in opposition to) a load force produced by a load placed, in use, on the beam, as described further below. The suspension members 4, 5 are elastic, and therefore they do not irreversibly deform as a result of the tension force (provided it does not exceed their elastic limit), and once it is removed they therefore return to their natural length. The suspension members 4, 5 may have a large elastic modulus, meaning that they deform very little under a high applied stress. To better understand the advantages provided by the load-bearing suspension member(s) first the loads on a standard, prior art beam arrangement, are described with reference to Figure 6. Figure 6 shows a standard beam 60, extending across an opening 62 (in which a swimming pool may be located), between two support points 64a, 64b, located at each outer edge of the beam (or at least any part of the beam outwards of these points may be disregarded when considering the loads that the beam must withstand). If a distributed load is applied onto the beam 60, i.e. as would be created by loads being placed on top of the beam, in use, and acted on by gravity, this creates a distributed downwards force 66 as seen in Figure 6. A bending moment diagram 68 illustrates schematically, with arrows, the bending moment created by the weight of the distributed load across the beam 60. As is demonstrated the largest bending load occurs in the centre of the beam 60 (i.e. the centre with respect to its length, along its elongate direction). This bending moment defines the maximum bending moment magnitude 70 (represented by a dashed line) which the beam must be constructed to withstand. The beam 60 must therefore be dimensioned (e.g. be sufficiently large and / or thick) to withstand this maximum bending moment 70. The bending load at the centre of the beam 60 creates an inwards force 61, towards the centre of the beam 60 and in the upper part of the beam 60, and correspondingly creates an outwards force 63 away from the centre of the beam 60, in a lower part of the beam, as seen in Figure 6. Figure 7 illustrates the induced bending moments when a distributed load 66’ is applied onto the beam arrangement according to the present invention, which includes both the beam 1 and also at least one suspension member 4 (and may also include a second or even several or more suspension members). As in the prior art, the beam 1 is supported at its two outer edges by two outer support points 64a’, 64b’. As described above, the suspension member 4 is tensioned. This creates a first tensile force 20a acting through the first length 4a of the suspension member4 and a second tensile force 20b acting through the second length 4b of the suspension member 4. These tensile forces 20a, 20b each have a horizontal component, parallel to the beam length, and have a vertical component 24a, 24b. The horizontal component of the tensile force 20a, 20b is counteracted by inwards horizontal forces 22a, 22b, which are applied at each of the side-member contact points 8a, 8b, acting towards the centre of the beam 1. The horizontal components of the tensile forces are balanced on either side of the central section 6, such that they produce no resultant force on the central section 6. The vertical component 24a, 24b of the tensile forces effectively create two additional support points for the overall beam 1. These effective support points 26a, 26b which are created at the point where the suspension member 4 contacts, and transfers the force to, the central section 6 of the beam 1, are shown with dashed lines. The effective support points 26a, 26b which are created by the tensioned suspension member 4 effectively divide the beam 1 into three sections, in terms of force distribution, with each beam extending between two support points. In this example each “section” is of equal length, since the beam contact points 10a, 10b are equidistant from each other and from the side-members (in terms of their distance along the length direction, not their total separation, since they are also separated in height as seen in Figure 7. The bending moment in each of these beam sections is illustrated in the bending load diagram 68’ in the lower part of Figure 7. Since each section is effectively a beam, and is across a smaller span than the prior art beam of Figure 6, which effectively spans the larger separation between the outer support points 64a, 64b, the maximum bending moment 70’ which occurs anywhere along the length of the beam 1, and therefore which the beam must be dimensioned to withstand, is smaller than the maximum bending moment 70 for the prior art beam. The beam 1 therefore does not need to be as strong as prior art beams, and therefore need not be as large or heavy. Thus the suspension member 5 distributes load vertically such that effectively the load through the beam is transferred only horizontally, as represented by the horizontal force arrows 22a, 22b in Figure 7. There are also outwards forces 28 acting in the lower part of each beam section, which result from the bending moment as described with reference to Figure 6, but these are generally small compared to the horizontal tensile force 22a, 22b. In order to provide the additional effective support points 26a, 26b, the suspension member 4 is tensioned. The amount of tension is selectable depending on the load which the pool cover 1 is desired to support, but preferably is such as to provide (approximately) the same upwards force as is provided by the external support points 64a’, 64b’. Preferably, the amount of tension is actually such that, when no load is acting downwards on the beam 1, there is a resultant upwards force on the central section 6 of the beam 1, due to the tension in the suspension members 4, 5, giving a resultant upwards bending moment 71 in load-free conditions as seen in the lower part of Figure 7. As a result of this force, the central part of the beam 1 is slightly raised which, if a suitable cover is placed over it, causes the central part of the cover 100 to be raised, helping water to run off the cover rather than pooling on it. By way of an example, if a tension of 15000N is applied to the suspension member 4, and the beam 1 if 12m long (i.e. across the width direction of the view of Figure 7) then the upwards forces 24a, 24b at each effective support point 26a, 26b will be approximately 600N. Thus the total support force will be 1200N, which is approximately 7.5% of the total tensioning force. It will be appreciated that for a shorter beam length, a greater proportion of the tensioning force will contribute to the support force. Thus if the beam length is reduced but the tensioning force remains the same (e.g. 15000N), a larger support force will be produced. Figure 8 is a perspective view showing the arrangement of Figure 5 from a different perspective. In this view the second side-member contact points 8b, 9b can be seen more clearly. Although shown here on the inside of the second elongate side member 106b (i.e. the side closer to the beam 1) it will be understood that in other examples they may also be placed on the outer (i.e. external) side of the elongate side member 106b. Figures 9 and 10 show a rear perspective view of a slightly different arrangement to that of Figure 7. In Figure 10, the side parts of both the beam 1 and also the end covering panel 110a have been omitted in order to show the suspension member more clearly. All like elements are labelled with the same reference numerals. This embodiment differs in that instead of two separate suspension members 4, 5 each clamped to both the first and second side-members 106a, 106b, instead there is provided a single suspension member 4’ which provides all of the described lengths (although other separate, additional suspension members may be present). This suspension member 4’ provides all of the lengths described above with reference to the first embodiment. Instead of being clamped to the first elongate side member 106a, the suspension member 4’ passes around a wheel 8’ (i.e. a roller, a sheave) which is located on the first side member 106a. The suspension member 4’ is therefore tensioned by pulling only on the ends close to the second side member 106b, and then placed under tension by clamping those ends at the contact points 8b, 9b on the second side member 106. It will be appreciated that in a further embodiment (not illustrated) a single suspension member may be provided which is looped in a suitable manner at contact points on both the first side member 106a and the second side member 106b, i.e. it is one continuous loop. In this embodiment a suitable amount of tensioning may be provided by selecting the appropriate length for the single, looped, suspension member such that once it is stretched to meet all of the contact points it is under the desired amount of tension. Figure 11 shows a cross-section of the central section 6 of the beam 1 taken along the line A shown in Figure 7. In this view the cross-sectional profile of the beam 1, in at least its central section 6, and the end covering panel 110a are visible. As is seen in this Figure, the suspension members 4, 5 are positioned on opposite sides of the beam 1 (i.e. adjacent opposite faces of the beam 1). The end covering panel 110a includes an upper flange 90 and a lower flange 92. The beam 1 includes an upper channel 94 and a lower channel 96. In order to secure the end covering panel 110a and the beam 1 together, the upper flange 90 is inserted into the upper channel 94 and the lower flange 92 is inserted into the lower channel 96. The beam 1 further includes a suspension member attachment portion 98. The beam 1 (i.e. in particular the suspension member attachment portion 98) includes two elongate grooves 91a, 91b, extending along the length of the central section 6 of the beam 1, i.e. parallel to the length of the beam. These grooves accommodate, in use, the connecting lengths 5c, 4c of the first and second suspension members 4, 5, as illustrated. The suspension member attachment portion 98 further includes a first retaining portion 93a and a second retaining portion 93b. These are shaped at their lower ends to accommodate the suspension members 4, 5 when placed over them, as illustrated in Figure 11. These retaining portions 93a, 93b, having been placed over the suspension members 4, 5 positioned in the grooves 91a, 91b, are then fixed in place by engagement with a further retaining structure 95 (e.g. a lip in the secondary portion). This secures the suspension members 5 in contact with the central section 6 of the beam 1. It will be appreciated that any other suitable connection means may be used. Figure 12 is a schematic drawing of a beam T and associated components, for a pool cover 100’ according to a further embodiment of the invention. Like components are labelled with the same reference numerals as are used for the embodiment of Figure 7, but followed by an apostrophe. Components which are the same will not be described again in detail. This embodiment differs from that of Figure 7 in that in addition to contacting the beam T at a first beam contact point 10a’, in a manner which applies the described forces, the first length of suspension member 4a’ also contacts the beam 1’ at another contact point, referred to herein as the first secondary beam contact point 15a’. Similarly, the second length of suspension member 4b’ also contacts the beam T at another beam contact point, referred to as the second secondary beam contact point 15b’. The tensile force 20a’, 20b’, acts also at the secondary contact points 15a’, 15b’. This force has a vertical component 224a’, 224b’ and a horizontal component 223a’, 223b’. In this case the horizontal forces act inwards towards the centre of the beam, and the vertical forces again act upwards, providing further upwards force on the beam at these contact points, reducing the bending moment which the beam must be able to withstand at these points. The secondary contact points 15a’, 15b’ may be provided by a protrusion or sheave, which the suspension member length 4a, 4b passes underneath or around, so as to convert its tensile force into an upwards lifting force on the beam. Figure 13 is a flow diagram illustrating a method of manufacturing a pool cover according to the present invention. In a stage 200, the beam 1 is formed. In a stage 202, the suspension members 4, 5 are connected to the central section 6 of the beam. This may be done using the method described above with reference to Figure 11. Alternatively, if no connecting section of the suspension member(s) is present then separate suspension member lengths may be connected on either side of the central section, i.e. at separate contact points. In stage 204, the beam 1 is attached to the first side member 106a and to the second side member 106b, so as to extend between them. In a stage 206 the suspension members 4, 5 are tensioned up to a desired tension level so as to provide the desired amount of supporting force to the beam 1 through the contact points, as described above, and are attached to the side members 106a, 106b in a suitable manner. Although shown in this particular order, it will be understood that the method steps need not necessarily be carried out in this illustrated order. For example, the beam 1 may be connected between the side members 106a, 106b before or after connecting the suspension members 4,5 to the central section 6. It will be appreciated by those skilled in the art that the invention has been illustrated by describing one or more specific embodiments thereof, but is not limited to these embodiments; many variations and modifications are possible, within the scope of the accompanying claims.

Claims

1. A cover for providing a floor structure over an opening, the cover comprising: a first elongate side member;a second elongate side member;a beam extending between the first elongate side member and the second elongate side member;a first length of elastic suspension member, connected between a first sidemember contact point, on the first elongate side member, and a first beam contact point on the beam, so as to apply a tensile force to the first length of elastic suspension member; anda second length of elastic suspension member, connected between a second side-member contact point, on the second elongate side member, and a second beam contact point on the beam, so as to apply a tensile force to the second length of elastic suspension member;wherein the tensile force in the first length of elastic suspension member and the second length of elastic suspension member provides a force to at least the first beam contact point and the second beam contact point, so as to provide a supporting force to the beam which acts against a load force produced by a load placed, in use, on the beam.

2. The cover of claim 1, wherein the cover is a swimming pool cover.

3. The cover of claim 1 or 2, comprising an elastic suspension member extendingcontinuously between the first side-member contact point and the second sidemember contact point, providing both the first length of elastic suspension member and the second length of elastic suspension member.

4. The cover of any preceding claim, wherein the first length of suspension member and the second length of suspension member are connected by a first connecting length of elastic suspension member, the first connecting length of elastic suspension member contacting the beam along substantially along all of its length5. The cover of any preceding claim, wherein the first length of elastic suspension member is fixedly connected to the first side-member contact point and wherein thesecond length of elastic suspension member is fixedly connected to the second sidemember contact point.

6. The cover of any of claims 1 to 4, wherein the first length of elastic suspension member is fixedly connected to the first side-member contact point and the second length of elastic suspension member is movably connected to the second side-member contact point.

7. The cover of any preceding claim, wherein the first beam contact point is located towards a lower edge of the beam and the second beam contact point is located towards the lower edge of the beam.

8. The cover of any preceding claim, wherein the first side-member contact point is located towards an upper edge of the first elongate side member and the second side-member contact point is located towards an upper edge of the second elongate side member.

9. The cover of any preceding claim, wherein the second elongate side member extends parallel to the first elongate side member, defining a cover plane, wherein the first side-member contact point is located at a first height relative to a direction perpendicular to the cover plane, and the first beam contact point is located at a second height relative to the direction perpendicular to the cover plane, wherein the second side-member contact point is located at the first height relative to the direction perpendicular to the cover plane, and the second beam contact point is located at the second height relative to the direction perpendicular to the cover plane, and wherein the first height is greater than the second height.

10. The cover of any preceding claim, further comprising a third length of elastic suspension member, connected between a third side-member contact point, on the first elongate side member, and a third beam contact point on the beam; and a fourth length of elastic suspension member, connected between a fourth side-member contact point, on the second elongate side member, and a fourth beam contact point on the beam; wherein the tensile force in the third length of elastic suspension member and the fourth length of elastic suspension member provides a force to at least the third beam contact point and the fourth beam contact point, so as to provide asupporting force to the beam which acts against a load force produced by a load placed, in use, on the beam.

11. The cover of any preceding claim, wherein the first length of suspension member is arranged to contact the beam at a secondary beam contact point, wherein the tensile force in the first length of elastic suspension member provides a force to the secondary beam contact point, so as to provide a supporting force to the beam which acts against a load force produced by a load placed, in use, on the beam.

12. The cover of any preceding claim, wherein the first beam contact point and the second beam contact point are separated along the length of the beam.

13. The cover of claim 12, wherein the first beam contact point is approximately equidistant from both the first side-member contact point and the second beam contact point, along the length of the beam, and wherein the second beam contact point is approximately equidistant from both the first beam contact point and the second-side member contact point, along the length of the beam.

14. The cover of any preceding claim, wherein the tensile force is arranged to cause a central portion of the beam to be raised up in the absence of an external load acting downwards on the beam.

15. The cover of any preceding claim, wherein the first length of elastic suspension member has a diameter of less than 20 mm.

16. The cover of any preceding claim, wherein the modulus of elasticity of the first length of elastic suspension member is at least 100 GPa.

17. The cover of any preceding claim, wherein the first length of elastic suspension member and the second length of elastic suspension member are metal wire.

18. The cover of any preceding claim, wherein the first length of elastic suspension member comprises steel.

19. The cover of any preceding claim, wherein the beam comprises aluminium.

20. The cover of any preceding claim, wherein the beam has a height of less than 300 mm.

21. The cover of any preceding claim, wherein the cover further comprises one or more wheels or castors.

22. The cover of any preceding claim, wherein the beam is a first beam, and wherein the cover further comprises a second beam, extending between the first elongate side member and the second elongate side member.

23. A method of manufacturing a cover for providing a floor structure over an opening, the method comprising:extending a beam between a first elongate side member and a second elongate side member;connecting a first length of elastic suspension member between a first sidemember contact point, on the first elongate side member, and a first beam contact point on the beam, so as to apply a tensile force to the first length of elastic suspension member; andconnecting a second length of elastic suspension member between a second side-member contact point, on the second elongate side member, and a second beam contact point on the beam, so as to apply a tensile force to the second length of elastic suspension member;wherein the tensile force in the first length of elastic suspension member and the second length of elastic suspension member provides a force to at least the first beam contact point and the second beam contact point, so as to provide a supporting force to the beam which acts against a load force produced by a load placed, in use, on the beam.

24. The method of claim 23, further comprising tensioning the first length of suspension member and the second length of suspension member using an external tensioning device.

25. The method of claim 23 or 24, comprising selecting a magnitude of the tensile force applied to the first length of suspension member and / or the second length of suspension member based on the load which the floor structure is intended to support.

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