The present invention relates to a modular foundation chamber apparatus, particularly but not necessarily exclusively to an apparatus suitable for supporting an electric vehicle charging station. Other types of above-surface structure, other than electric vehicle charging stations, will of course be feasible to use in conjunction with the modular foundation chamber apparatus. A method of assembling a modular foundation chamber apparatus is also provided.

In many contexts, there is a requirement for boxes housing electrical, or other types of, cable above ground, where said cables would ordinarily be routed underground. Such abovesurface structures are commonly referred to as street furniture, including electric vehicle charging stations, telecommunications boxes, traffic signal control units, for instance. It will be apparent that such structures are not necessarily purely for use in traditional ‘street’ contexts; similar constructions are required, for example, adjacent motorways and railway lines.

Although cables are essential for providing power to, for example, an electric vehicle charging station, the cables can be unsightly. Storage apparatus are used widely to store cables below the surface of the ground and therefore to hide the cables from public view.

The cable housing can be pre-assembled, before the housing is placed into a cavity in the ground. The assembly, and the combination of the components, is usually performed from the base up. The components of the housing therefore need to be welded and/or otherwise secured together; this can take a large amount of time.

It is also possible that the lifting and placement of the housing into the cavity could result in weakening of any fasteners used, potentially allowing water and/or surrounding ground soil to enter the cabling void of the housing. This pre-assembly could make it difficult to place the potentially heavy housing into the cavity, and therefore machinery may be required.

Once the housing is assembled, the housing could end up being the incorrect height for the cavity and it will be difficult to take the housing apart as the components of the housing have been welded together.

It may also be difficult to access the cables within the cabling void once a cap of the housing has been connected.

It is an object of the present invention to provide a modular foundation chamber apparatus that solves or alleviates one or more of the above stated problems. According to a first aspect of the invention, there is provided a modular foundation chamber apparatus for housing cabling and mounting above ground an above-surface structure, the modular foundation chamber apparatus comprising: a base member having an anchoring connector thereon; a chamber body stackable onto the base member to define a cabling void; a top member having a cable access aperture therethrough, the top member being stackable onto the chamber body; and a securing element connectable with the anchoring connector and connectable to the top member to clampingly secure the chamber body between the base member and the top member.

It is advantageous that the modular foundation chamber apparatus can be assembled modularly from the base up, providing the user with a convenient assembly procedure from above. This promotes ease of assembly as no welding is required to interconnect the components of the modular foundation chamber apparatus, and therefore the apparatus can be disassembled if the modular chamber foundation apparatus is required to have a height alteration. Similarly, there is no need for an installer to enter into a trench in which the apparatus is located to perform the assembly; all work can be conducted from above.

Optionally, the base member may comprise a frame. A frame having an at least in part open portion may reduce the weight of the apparatus as well as providing a potential fluid escape path in the event of water ingress into the cabling void. This may also improve manufacturing simplicity.

Optionally, the top member may comprise a frame. This is advantageous as this structure allows for the easy access to the cables once the cover plate has been removed, since there is already a cable access aperture present within the top member due to its frame-like structure.

Preferably, the chamber body may further comprise a plurality of chamber body portions which are stackable onto one another. Having a plurality of chamber body portions allows for the user to assemble the modular foundation chamber apparatus to a desired height, and the clamping process does not result in any loss of structural integrity as a result.

Preferably, the plurality of chamber body portions may comprise a first chamber body portion and a second chamber body portion, wherein the first chamber body portion has at least one cable port and the second chamber body portion is different to the first chamber body portion. The first and second chamber bodies are stackable to form the chamber body, and the cable port allows for the cables that are external to the modular foundation chamber apparatus are able to access the modular foundation chamber apparatus. Subsequently, a portion of the cables are housed within the cabling void, the cables being able to connect to an abovesurface structure through the cable access aperture. Typically, one would expect the cable port to be positioned at the base of the chamber body, with non-ported portions stacked on top to limit dirt or water ingress into the cabling void.

Optionally, the chamber body comprises an inner wall and an outer wall, wherein the inner and outer walls may define a securing element channel for receiving the securing element. The securing element channel provides a means of guiding the securing element into position through the chamber body, or a guiding means for receiving the chamber body or chamber body portions onto a pre-assembled base member with a securing element. This simplifies the assembly process.

Optionally, each chamber body portion of the plurality of chamber body portions may comprise an inner portion-wall and an outer portion-wall which form the said inner and outer walls of the chamber body when the chamber body portions are stacked on top of one another. The inner portion-wall and the outer portion-wall advantageously combine to form the inner wall and the outer wall, therefore depending on how many chamber body portions are stacked on top of one another, the inner and outer walls can be made to a desired height.

Preferably, the anchoring connector may extend into the securing element channel from the base member. This is advantageous as the user can easily identify the correct position for the securing element and the anchoring connector to interconnect. The anchoring connector thus also serves as an additional locator for receiving the chamber body in position, simplifying installation.

Optionally, the base member may comprise at least one locator for locating the chamber body onto the base member. The locator advantageously provides the user with the ability to position the chamber body on top of the base member and prevents the base member from moving on the surface of the base member.

Advantageously, the securing element and the anchoring connector preferably screw- threadingly interengage with one another. The screw-threading engagement provides the securing element and the anchoring connector to have a secure interconnection and therefore provide a strong clamping force to the chamber body. Optionally, the securing element may be selectably assembleable to a desired length. Given that the height of the modular foundation chamber assembly is alterable, it stands to reason that it may be desirable to modularly extend the securing element.

Optionally, the top member may comprise a locator for positioning the chamber body. Locators can simplify the correct positioning of the top member so that the chamber body is correctly oriented.

Advantageously, the top member may preferably comprise a first aperture and a second aperture to receive the securing element. Preferably, the first aperture may have a larger area than the second aperture, the first aperture may have an area greater than that of a connector for engaging the securing element with the top member, the second aperture may have an area less than that of the connector. This multi-aperture configuration allows for the connector to hold the securing element in place at the top member to be recessed relative to the top of the cover plate. There are therefore no above-surface projections which would reduce the effectiveness of the cover plate as a walkway.

Optionally, the top member may have a cover plate support for receiving a cover plate. The purpose of the apparatus is to provide a walkable surface over the foundation chamber once installed, and therefore a suitable cover plate support is highly desirable.

Preferably the modular foundation chamber apparatus may further comprise a cover plate, the cover plate being releasably engageable with the cover plate support to cover the cable access aperture.

Optionally, the cover plate may cover the first and second apertures to prevent access to the securing element when the cover plate is in place. The hiding of the apertures prevents tampering with the foundation chamber, as well as reducing the risk of water ingress.

Preferably, the cover plate may comprise a blank plate support adjacent an access opening of the cover plate and a removable blank plate receivably engageable with the blank plate support to cover the access opening. Optionally, the blank plate support may be connectable to the cover plate support. The provision of a blank plate provides a means of rapidly converting the apparatus from a walkway-suitable apparatus into a usable above-surface structure support, through which cables can be passed. The blank plate support also advantageously provides a neat position for connecting the cover plate to the cover plate support in a hidden manner.

Advantageously, the cover plate may have an adapter connection portion for attaching an adapter for an above-surface structure thereto. The modular foundation chamber apparatus may further comprise an adapter, the adapter being releasably engageable with the adapter connection portion. In this case, it is desirable to provide a means of connecting the abovesurface structure easily and quickly, and the adapter arrangement is a simple means of doing so.

According to a second aspect of the invention, there is provided a method of assembling a modular foundation chamber apparatus, the steps comprising: a] stacking a chamber body onto a base member to define a cabling void; b] stacking a top member onto the chamber body, the top member having a cable access aperture therethrough; c] connecting a securing element with an anchoring connector of the base member and connecting the securing element with the top member to clampingly secure the chamber body between the base member and the top member, thereby forming a modular foundation chamber apparatus.

It is clear that the modular assembly of the modular foundation chamber apparatus is advantageous due to the ease of assembly. The user needs to simply stack a chamber body on top of the base member and then stack a top member on top of the chamber body. A securing element is connected to clamp the chamber body between the base member and the top member, providing the modular foundation chamber apparatus with a securely fastened housing for cables.

Most importantly, the user is able to assemble the modular foundation apparatus chamber from the base up; there is no need to assemble the apparatus above ground and then use machinery to lift the apparatus into the hole. The user can stack the base member, chamber body and top member into the hole and secure the modular foundation chamber apparatus using the securing element. The securing element connects to the anchoring connector at the base member and then the securing element connects to the top member to provide a clamping force.

Preferably, the chamber body further comprises a plurality of chamber body portions which are stackable onto one another and during step a], a first chamber body portion of the plurality of chamber body portions may be stacked onto the base member and at least one second chamber body portion of the plurality of chamber body portions may be stacked onto the first chamber body portion to form the chamber body. The provision of a multi-portion chamber body allows for height adjustment, without compromising on the structural integrity of the whole apparatus, due to the clamping arrangement created by the structure.

Optionally, during step c], the connecting of the securing element with the anchoring connector may be performed from the top of the modular foundation chamber apparatus and wherein connecting of the securing element to the top member may be performed from the top of the modular foundation chamber apparatus. Top-down assembly of the apparatus greatly simplifies the ease with which a foundation chamber can be built.

The invention will now be more particularly described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 shows an isometric representation of one embodiment of a modular foundation chamber apparatus in accordance with the first aspect of the invention;

Figure 2 shows an exploded isometric representation of the modular foundation chamber apparatus of Figure 1 ;

Figure 3 shows a first step of an assembly process of the modular foundation chamber apparatus of Figure 1 , in which a first chamber body portion is installed onto a base member;

Figure 4 shows a second step of an assembly process of the modular foundation chamber apparatus of Figure 1 , in which a second chamber body portion is installed onto the first chamber body portion;

Figure 5 shows a third step of an assembly process of the modular foundation chamber apparatus of Figure 1 , in which a top member is installed onto the second chamber body portion;

Figure 6 shows a fourth step of an assembly process of the modular foundation chamber apparatus of Figure 1 , in which at least one securing element is installed from the top member to the base member;

Figure 7 shows a fifth step of an assembly process of the modular foundation chamber apparatus of Figure 1 , in which a cover plate is installed onto the top member; Figure 8 shows an isometric representation of an underside of the cover plate of the modular foundation chamber apparatus of Figure 7;

Figure 9 shows an isometric representation of the top member of the modular foundation chamber apparatus of Figure 7;

Figure 10A shows an isometric representation of the modular foundation chamber apparatus of Figure 7, inclusive of a blanking plate, shown in a detached condition;

Figure 10B shows the modular foundation chamber apparatus of Figure 10A, with the blanking plate in a blanking condition;

Figure 11 A shows a side view of the modular foundation chamber apparatus of Figure 10B;

Figure 11 B shows a vertical cross-section through line C-C of Figure 11A; and

Figure 12 shows an indicative in-use arrangement of the modular foundation chamber apparatus with an above-surface structure mounted onto the cover plate.

Referring to Figure 1 , there is indicated a modular foundation chamber apparatus referenced globally at 10. The modular foundation chamber apparatus 10 is designed to act as a housing for electrical cables below ground, for introduction to an above-surface structure.

The modular foundation chamber apparatus 10 comprises a chamber body 12 which comprises a plurality of chamber body portions 12a, 12b. Of the plurality of chamber body portions 12a, 12b, there is illustrated a first chamber body portion 12a and a second chamber body portion 12b. The first and second chamber body portions 12a, 12b are interconnectable to build the chamber body 12. The chamber body 12 is preferably made of a rigid material such as plastic, fibreglass or metal. Whilst two chamber body portions 12a, 12b are shown, it will be apparent that, given the stackable arrangement, any number of chamber body portions could be provided, though typically only one first chamber body portion would be present. It is entirely feasible that a single non-portioned chamber body be provided.

The first chamber body portion 12a is attached to a base member 14, which would be received on the base of any trench in which the modular foundation chamber apparatus 10 is to be installed. The first chamber body portion 12a has at least one cable port 16, here shown with cable port caps 18 situated in side walls 20 thereof. This provides cable access into the chamber body 12. Said cable ports 16 could be pre-fabricated, or could be machined in situ as required.

The second chamber body portion 12b is stacked on top of the first chamber body portion 12a. The side walls of the second chamber body 20 portion broadly align with the corresponding side walls 20 of the first chamber body portion 12a. The second chamber body portion 12b is preferably made of the same material as the first chamber body portion.

A top member 22 is then positioned on top of the second chamber body portion 12b. The top member 22 is parallel to the base member 14 once installed, and the first and second chamber body portions 12a, 12b are situated between the top member 22 and the base member 14. Attached to the top member 22 is a cover plate 24, said cover plate 24 being visible at the ground surface, and indeed acting as a walkway over the modular foundation chamber apparatus 10 once installed. The top member 22, base member 14 and the cover plate 24 are preferably made of a rigid material such as plastic, fibreglass or metal.

The cover plate 24 comprises a removable blank plate 26 therein, the removable blank plate 26 being fastenable to the cover plate 24. This may be achieved, for example, by the use of a screw-threaded fastener. The cover plate 24 may have an anti-slip surface to provide grip for any individual stepping on the cover plate 24 when the modular foundation chamber apparatus 10 is not being used to support an above-surface structure.

There is an adapter connection portion 28 for attaching an adapter for an above-surface structure to the cover plate 24, which here takes the form of an array of screw-threaded receivers in the top surface of the cover plate 24.

Figure 2 shows an exploded view of Figure 1 , revealing some of the hidden components, and in particular, the cabling void 30 which is positioned inside the modular foundation chamber apparatus 10 in use. The base member 14 is preferably formed as a frame, having four structural members 32 arranged in the shape of a rectangle, surrounding a central aperture. The structural members 32 may be hollow to reduce the weight of the base member 14. The base member 14 is shown to have at least one locator 34. The locators 34 shown are integrally formed with an inner surface of the frame. The locators 34 each have an in-use upwardly projecting tang which receivably engages with the side wall 20 of the first chamber body portion 12a. The base member 14 is also shown to comprise a chamber-body-contact surface 36. The chamber-body-contact surface 36 is a surface of the base member which receives the chamber body 12 when the chamber body 12 is stacked onto the base member 14. The base member 14 has an anchoring connector 38 associated therewith, which in the depicted embodiment extends up through the frame through the hollow structural members 32, so as to sit proud of the chamber-body-contact surface 36.

The chamber body 12 is shown to comprise an inner wall 40 and an outer wall 42 defining a securing element channel 44 therebetween. As the chamber body 12 is here comprised of the first and second chamber body portions 12a, 12b, each of the first and second chamber body portions 12a, 12b have an inner portion-wall 40a, 40b and an outer portion-wall 42a, 42b.

Positioned the inner portion-walls 40a, 40b and outer portion-walls 42a, 42b of the first and second chamber body portions 12a, 12b, and by extension the inner wall 40 and outer wall 42 of the whole chamber body 12, are at least one brace element 46. The brace elements 46 interconnect the inner wall 40 and outer wall 42, and also create discrete securing element channels 44 within the chamber body 12. The brace elements 46 also provide structural support for the chamber body 12, to avoid buckling of the outer wall 42.

The top member 22 is constructed in a similar manner to the base member 14, though they could be formed so as to be wildly different to one another. The top member 22 is preferably formed as a frame, having four structural members 32 arranged in the shape of a rectangle, with a cable access aperture 48 being formed therein. The structural members 32 may be hollow to reduce the weight of the top member 22. The top member 22 is shown to have at least one locator 34. The locators 34 shown are integrally formed with an inner surface of the frame. The locators 34 each have an in-use downwardly projecting tang which receivably engages with the side wall 20 of the second chamber body portion 12b.

The top member 22 also has a cover plate support 50. The cover plate support 50 comprises a perimetric upstanding rim 52, the cover plate 24 being receivably engageable with the cover plate support 50. The cover plate support 50 also here comprises a pair of bridging members 54 either side of the cable access aperture 48 which have fasteners associated therewith for securing the cover plate 24 in place. The top member 22 also comprises at least one first aperture 56 in a receiving surface 58 of the cover plate support 50. Four such first apertures 56 are indicated. The cover plate 24 includes a blank plate support 60 adjacent an access opening 62 of the cover plate 24, with the removable blank plate 26 being receivably engageable with the blank plate support 60 to cover the access opening 62. The blank plate support 60 is engagable with the bridging members 54 of the cover plate support 50 to hold the cover plate 24 in place, whilst the blank plate 26 is securable using one or more fasteners, typically screw-threaded fasteners. Other connection means will of course be apparent to the skilled person, such as a bayonet type engagement.

The first apertures 56 are dimensioned to receive a securing element 64 therethrough, as well as a connector 66, such as a nut and washer, for fixing the securing element to the top member 22. Corresponding second apertures 68, only visible in Figure 11 B, are provided aligned with the first apertures 56, and which are dimensioned to receive the securing elements 64 therethrough, but which are sufficiently small to provide an anchor point for the connectors 66. The first and second apertures 56, 68 once installed, are aligned to the anchoring connectors 38 of the base member 14.

Each securing element 64 is an elongate member which is received by the securing element channel 44. The securing element 64 is made of a rigid material such as plastic, fibreglass or metal. A top portion 70 of the securing element 64 is engaged with the top member 22 using the connector 66, the top portion 70 here having an external screw thread. A bottom portion 72 of the securing element 64. The securing element 64 is dimensioned to a correct height of the modular foundation chamber apparatus 10 in order to interconnect the top member 22 with the base member 14, though it will be apparent that a modularly extendible securing element could be provided, which increases in length according to the height of the modular foundation chamber apparatus 10.

Figures 3 to 7 show a step-by-step assembly process of the modular foundation chamber apparatus 10. The modular foundation chamber apparatus 10 is assembled from the base member 14 upwards so as to promote the ease of assembly within a below-surface trench.

Again, whilst the assembly is shown in respect of a chamber body 12 having first and second chamber body portions 12a, 12b, it is clear that the assembly process is feasible regardless of the number of chamber body portions used, if any.

The first chamber body portion 12a is placed onto the base member 14, as depicted in Figure 3, the position of the first chamber body portion 12a being assisted via the provision of the locators 34, which abuttably engage with an inner surface of the inner-wall portion 40a of the first chamber body portion 12a. The anchoring connectors 38 nestle within the securing element channels 44 of the first chamber body portion 12a.

The second chamber body portion 12b, as shown in Figure 4, is then stacked onto the first chamber body portion 12a, the first and second chamber body portions 12a, 12b aligning so that the inner portion-wall 40a, 40b and the outer portion-wall 42a, 42b collectively form the securing element channel 44. The securing element channel 44 is by default aligned with the anchoring connector 38 from top to bottom.

The top member 22 is, as shown in Figure 5, stacked onto the second chamber body portion 12b. The positioning of the top member 22 is aided by the locators 10 which abuttably engage with an inner surface of the inner-wall portion 40b of the second chamber body portion 12b. At this point, the first and second apertures 56, 68 are each aligned to the counterpart anchoring connector 38.

Each securing element 64 is inserted through a first aperture 56 of the top member 22 and subsequently the second aperture 68 thereof, as shown in Figure 6, to enter the securing element channel 44. The securing element 64 is engaged with the anchoring connector 38, typically by screwing the bottom portion 72 of the securing element 64 into place with a suitable tool.

The securing element 64 is then secured to the top member 22 using the connector 66. The connector 66 may be integrally formed with the top portion 70 of the securing element 64 or the connector 66 may be discrete from the securing element 64. Once the connector 66 secures the securing element 64 to the top member 22, the top portion 70 of the securing element 64 remains received by the second aperture 68. The connector 66 remains hidden from view within the structural member 32 of the top member 22.

The cover plate 24 is then placed onto the top member 22, as shown in Figure 7. Specifically, the cover plate 24 contacts, and is therefore supported by, the cover plate support 50 of the top member 22. Secure fixing is here achieved by connection through the blank plate support 60 to the bridging members 54 of the cover plate support 50.

Figure 8 shows the underside of the cover plate 24. The blank plate support 60 protrudes into an access opening 62 to support the removeable blank plate 26. The blank plate support 60 here comprises elongate members engaged to the underside 74 of the cover plate 24, the underside 74 being the side in-use facing the cabling void 30. The sub-surface structure 76 of the adapter connection portion 28 is also shown, formed as downwardly depending structures within which are mounted stud connectors 78, thus forming the screw-threaded receivers visible in Figure 1.

Figure 9 shows the top member 22 in further detail. There are upstanding fasteners 80 held captive within the bridging members 54 which are able to receivably engage with the blank plate support 60 directly.

Figures 10A and 10B show the positioning of the cabling access aperture 48 and the removable blank plate 26 covering the cabling access aperture 48 respectively.

The removeable blank plate 26 is complementarily-shaped to the cable access aperture 48 and is attached to the cover plate 24 using one or more fasteners.

Figure 10B illustrates a scenario for use of the modular foundation chamber apparatus 10. The blank plate 26 is installed, and thus a continuous walkway is formed by the cover plate 24. The modular foundation chamber apparatus 10 can thus be installed in a manner similar to any traditional manhole cover; however, the cover plate 24 is adapted to receivably engage with an adapter for above-surface structures. The blanking plate 26 is thus removable to provide cable access through the cabling access aperture 48.

Figure 11A demonstrates a side profile of the modular foundation chamber apparatus 10. It can be observed that the top member 22 is stacked on top of the second chamber body portion 12b, that the second chamber body portion 12b is stacked on top of the first chamber body portion 12a, and the first chamber body portion 12a is stacked onto the base member 14. The entire modular foundation chamber apparatus 10 is held together in a clamped arrangement, as will be apparent from the cross-section shown in Figure 11 B through line C-C of Figure 11 A.

From this cross section, the form of the anchoring connector 38 can be seen, here provided as a coach bolt 82 coupled to a stud connector 84 within a structural member 32 of the base member 14. The first and second apertures 56, 68 can also be seen in the top member 22, with the first aperture 56 having a larger area than the second aperture 68.

The larger area of the first aperture 56 allows the user to threadingly engage the connector 66 with the securing element 64. The smaller area of the second aperture allows a secure attachment of the connector 66 with the top portion 70 of the securing element 64, clamping the securing element 64 against the structural member 32 of the top member 22. The securing element 64 is housed within the securing element channel 44 between the inner 40 and outer walls 42 of the chamber body 12. The anchoring connector 38 and a bottom portion 72 of the securing element 64 screw-threadingly interengage with one another. The coupling between the anchoring connector 38 and the securing element 64 can thus be tightened entirely from above, by cranking of the connector 66 to provide a clamping force to hold the position of the chamber body 12. A strong modular foundation chamber apparatus 10 is thus provided.

Figure 12 shows an installed system 100 the modular foundation chamber apparatus 10 disposed in a trench 86 below the ground surface 88. The modular foundation chamber apparatus 10 is also shown in use here with the above-surface structure 90. The abovesurface structure 90 is attached to the cover plate 24 via an adapter 92, which may be an adapter plate or similar receiver, connected to the cover plate 24 via the adapter connection portion 28. The adapter 92 may be attached to the adapter connection portion 28 via a twist lock or a screw.

The top member is flush or substantively flush with the ground surface. The modular foundation chamber apparatus is therefore not visible above the surface - only the top member is visible. This hides the modular chamber apparatus from the user.

The first chamber body and the second chamber body could be made out of different materials. For example, the first chamber body can be made of fibreglass and the second chamber body can be made of plastic.

The first and second chamber bodies are described as having four walls, but it is feasible that each chamber body has at least three walls.

The first and second chamber body portions are described having a rectangular shape, however the first and second chamber body portions could also have a polygonal shape with at least three walls.

The attachment means is described as a screw, however the removable plate could be attached to the cover plate via a hinge mechanism which in turn creates a door opening into the cabling void.

The anchoring connector is described as extending through the base member. It is however feasible that the anchoring connector may be contained within the base member. The adapter is described as a plate however it is feasible that the adapter can be a cap attached over the cover plate or a frame attached to the cover plate.

It is therefore possible to provide a modular foundation chamber apparatus for housing cabling, the apparatus being assembled modularly for increased ease of installation. The modular nature of the modular foundation chamber apparatus provides the user with the option to alter the height of the modular foundation chamber apparatus and also prevents the need of heavy machinery to lift a fully assembled apparatus into the ground cavity.

After the apparatus is assembled, it is still possible to alter the height of the apparatus and it is easy to access the cables within the cabling void when maintenance is required. The cables can be accessed by removing the cover plate and/or removing the removable blank plate.

The words ‘comprises/comprising’ and the words ‘having/including’ when used herein with reference to the present invention are used to specify the presence of stated features, integers, steps, or components, but do not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination.

The embodiments described above are provided by way of examples only, and various other modifications will be apparent to persons skilled in the field without departing from the scope of the invention as defined herein.