GB2504921A - An access tile assembly for a raised floor - Google Patents

Abstract

An access tile assembly for a raised floor comprises at least one tile 3 comprising a peripheral support frame adapted to rest on vertical stands 5. The support frame defines a plurality of access apertures 15 within the periphery of the frame, each with at least two opposed supports. The assembly includes a plurality of modules adapted to fit in the apertures, each module comprising at least one of a planar blanking plate to close the aperture or an aperture access plate comprising an opening. The supports may be recessed below a top plane of the access tile. The modules may comprise v-shaped reinforcement on its underside. A corner clamp 7 may be provided to secure a corner of the tile to an upright of the raised floor. Further modules may include a lockable storage box, a cable demarcation point or an attachment to support cables beneath the tile.

Description

AN ACCESS TILE ASSEMBLY FOR A RAISED FLOOR

The present invention relates to an access tile assembly for a raised floor and particularly but not exclusively relates to an access tile assembly for use with a raised floor in a data room for example.

It is well known to provide raised floors, particularly in commercial buildings. Such raised floors typically comprise a plurality of vertical stands spaced around the area in question and which rest on an underlying substrate, typically a concrete floor for example. The raised floor is supported on top of the stands so as to define a void underneath the floor. The raised floor then supports whatever equipment and office furniture is required. The cabling from the equipment can pass through the raised floor and into the void so that the cabling is hidden underneath the floor. The void beneath the floor can also be used to aid ventilation and cooling of the room concerned. Such an arrangement is typically used in a temperature controlled data room in which IT equipment is located, with the large amount of cabling being fed through the floor into the void underneath, and then out into the remainder of the building.

A raised floor can typically comprise a plurality of standard sized tiles. With the tiles in place, it is only once the IT equipment is selected and/or located on top of the raised floor that the exact positions of the cabling is known, ie, exactly where the cabling needs to be fed through the raised floor and into the void beneath. Often the tile is cut or drilled at the position required. This undesirably involves extra labour, time, mess and cost. Such alterations can also cause irreversible damage to the existing floor, likely beyond the acceptable limits of PSA MOB specification.

It has been proposed to provide replacement access tiles which are provided with a plurality of access apertures and blanking plates. However, the access apertures are of fixed size and position. This fixed size and position may not correspond ideally to the position of, and number of, cables in question.

There is a further requirement that the raised floor is sufficiently strong and hard wearing to support potentially relatively heavy equipment. For example, a computer server cabinet may be considerably heavier than normal office furniture. Some prior art access tiles are of relatively weak construction. It is also desirable to be able to avoid, or minimise, use of power tools in the installation of a raised floor.

The present invention sterns from some work in trying to provide an improved tile.

According to a first aspect of the invention there is provided an access tile assembly for a raised floor, the access tile assembly comprising at least one access tile comprising a peripheral support frame the underside of which is adapted to rest on vertical stands of the raised floor to form a void beneath the access tile, the topside of which comprises a floor surface for supporting items on the acccss tile, the support frame defining a plurality of access apertures within the periphery of the frame, the apertures enabling access to the void beneath the access tile in use, each aperture being provided with at least two opposed supports, the assembly further comprising a plurality of removable modules, at least one module being provided for each aperture, each module being adapted to be received in an aperture and to rest on the supports, each module comprising at least one of: a planar blanking plate to close the aperture, the blanking plate comprising a planar floor surface; and an aperture access plate comprising an opening to enable access to the void beneath the access tile in use.

The supports may be recessed below a top plane of the access tile, each module comprising a planar top floor surface such that when a module is received in an aperture, the planar top floor surface of the module is flush with the plane of the floor surface of the access tile.

More than one of each type of module may be provided.

The opening of the module comprising the aperure access plate may extend substantially the length of the plate, from a position adjacent one end of the module to a position adjacent the other end of the module.

A module may be provided comprising a partial aperture access plate, comprising an opening extending only partially the length of the plate, the remainder of the plate comprising a planar floor surface.

Preferably each aperture access plate further comprises a blanking plate dimensioned to be received in, and to blank the opening, the blanking plate comprising a planar floor surfacc.

A module may be provided comprising a storage box dimensioned to be received in an access aperture. The storage box may be lockable.

Preferably the floor surface of each module comprises reinforcement, on the underside of the floor surface. The reinforcement may comprise an elongate reinforcing bar extending along at least part of the floor surface. The reinforcement may comprise a reinforcing sheet of Vt shaped transverse cross section which extends along at least part of the underside of the floor surface, the outer margins of the sheet being secured to the tloor surface, with the apex of the V spaced from the floor surface.

A brush strip may be provided along at least one margin of the opening of the (partial) aperture access plate, the brush strip comprising a laterally projecting brush that cxtends along a margin of the opening and projects across the opening so as to partially close the opening, but to deflect around any cables or other objects extending through the opening.

A corner clamp may be provided comprising engagement means operative to engage a corner of the access tile, and clamping means operative to secure the corner clamp to an upright of the raiscd floor.

Preferably, the corner clamp is of sheet metal construction and comprises a base and engagement means upstanding from the base and comprising an upper channel comprising laterally spaced apart ends that are at 45° to the base when viewed in plan, the channel engaging the underside of the access tile in use, the clamping means extending around the upright of the raised floor and being secured to the base.

The clamping means may comprise a separate bracket adapted to engage the corner clamp.

An intermediate clamp may be provided comprising engagement means operative to engage a margin of the access tile, and clamping means operative to secure the intermediate clamp to an upright of the raised tloor.

Preferably, the intermediate clamp is of sheet metal construction and comprises a base and engagement means upstanding from the base and comprising an upper channel comprising laterally spaced apart ends that are at parallel0 with the base when viewed in plan, the channel engaging the underside of the access tile in use, the clamping means extending around the upright of the raised floor and being secured to the base.

Preferably the ends of the channel are sufficiently spaced apart that each cnd of the channel can engage a respective access tile, when the clamp is in use with adjacent access tiles.

A module may be provided comprising a cable demarcation point, that is, an electrical or data terminal or connection for terminating a given cable routed to the cable demarcation point.

A module may be provided comprising an attachment for support cables beneath the access tile, the attachment comprising a cable support attached to and spaced below the access tile.

According to a second aspect of the invention there is provided a raised tloor comprising the access tile assembly of the first aspect of the invention.

According to a third aspect of the invention there is provided a clamp for use with an access tile asscmbly of the first aspect of the invention, the clamp being of sheet mctal construction and comprises a base and engagement means upstanding from the base and comprising an upper channel comprising laterally spaced apart ends which engages the underside of the access tile in use, the clamping means extending around the upright of the raised floor and being secured to the base.

The clamp may comprise a corner clamp wherein the laterally spaced apart ends are at 45° to the base, when viewed in plan.

The clamp may comprise an intermediate clamp where tile laterally spaced apart ends are parallel with the base, when viewed in plan.

Other aspects of the present invention may include ally combmation of the features or limitations referred to herein.

The present invention may be carried into practice in various ways, but embodiments will now be described by way of example only with reference to the accompanying drawings in which: Figure I is a perspective view of an access tile assembly in accordance with the invention, with part of the assembly cut-away; Figure 2 is a plan view of a corner of the access tile assembly of Figure 1; Figure 3 is a plan view of an intermediate region of the access tile assembly of Figure 1; Figure 4 is a plan view of an access tile of the access tile assembly of Figure i; Figure 5 is a view from underneath the access tile of Figure 4; Figure 6 is a sectional view through line A-A of Figure 4; Figure 7 is a perspective view from underneath of the access tile of Figures 4 to 6; Figure 8 is a perspective view from above of the access tile of Figures 4 to 7; Figures 9a to 9e are plan, side, underneath, end and perspective views of a module comprising part of the access tile assembly of Figures i to 8; Figures ba to lOd are side, plan, end and perspective views of another module comprising part of the access tile assembly of Figures 1 to 8; Figures ha to lib are end and perspective views of another module comprising part of the access tile assembly of Figures 1 to 8; Figures 12a to Dc are plan, side, underneath, end and perspective views of a further module comprising part of the access tile assembly of Figures 1 to 8; Figures 13a to 13b are end and perspective views of a removable blanking plate adapted to be mounted on the module of Figure 12; Figures 14a to 14d are front, plan, rear and side views of a corner clamp comprising part of the access tile assembly of Figures 1 to 13; Figures iSa to 15d are front, plan, rear and side views of an intermcdiate clamp comprising part of the access tile assembly of Figures 1 to 14; Figures i6a to 16d are plan, end, side and end views of an equipment bracket comprising part of the access tile assembly of Figures 1 to 15; Figures l7a to 17c are sectional side, exploded perspective, and perspective views of a module comprising a storage box of the access tile assembly of Figures ito 16; Figures iSa to iSb are end and side views of a brush strip for use with the removable plate of Figures 9 to 13; Figure 19 is a perspective view of a cable tray attachment for the access tile assembly of Figures 1 to 18; and Figures i9a to 19e are respectively front and side views of part of the attachment of Figure 18, and preassembly, front and end views of another part of the attachment of Figure 18.

Referring initially to Figures 1 to 3, an access tile assembly 1 comprises a plurality of access tiles 3 arranged to form part of a raiscd floor. The underside of the corner of each access tile 3 is adapted to be supported by a respective upright 5 of the floor, adjacent access tiles 3 sharing an upright 5. The corner of each outermost access tile 3, that is, the outer corner of the access tiles 3 forming the periphery of the raised floor, is clamped to an upright 5 via a corner clamp 7. Intermediate access tiles 3 are clamped together, and to an upright 5, by an intermediate clamp 9.

Referring additionally to Figures 4 to S, each access tile 3 is oblong in plan and is formed from cut and folded sheet metal. The periphery of the sheet is folded downwardly and underneath planar top floor surface 11 to form a peripheral foot 13.

The floor surface 11 is formcd with three equal sized rectangular access apertures 15 equispaced across the floor surface 11. The underside of the floor surface 11 is reinforced with four reinforcing cross bars 17 that extend across the apertures 15 from front to back of the floor surface 11. Two of the cross bars 17 extend across central aperture ISA such that part of their upper surfaces are exposed to form elongate supports 19 along the outer margins of the central aperture ISA. The other two cross bars 17 extend across inner margins of the outer apertures 15B to form further elongate supports 19. Additional outermost supports 21 are provided by shorter strips located along the outer margins of the outer apertures 1SB.

The two pairs of cross bars 17 are further reinforced by n' shaped cross section channels 23, a respective channel 23 being located between each pair of cross bars 17.

Further reinforcement is provided by three lateral bars 25 that extend transversely across floor surface 11, adjacent an end margin of each aperture 15.

The access tile assembly 1 further comprises a plurality of modules that are arranged to fit in the apertures 15, to rest on the supports 19. The modules enable each access tile 3 to be tailored to the particular requirements in question, by selectively fully or partially blanking the appropriate access aperture(s) 15.

Referring additionally to Figure 9, a first module comprises a blanking plate 31 of sheet metal having a rectangular top floor surface 33, and two folded down ends 35.

A reinforcing rod 37 extends between the two ends 35 underneath the floor surface 33 and supports the apex of a V shaped support sheet 37. The support sheet 37 is also rectangular when viewed in plan and extends along the length of the removable

S

plate 31, between the ends 35. The two side margins of the removable blanking plate 31 are provided with a plurality of predrilled countersunk holes 39.

The removable blanking plate 31 is dimensioned to be received within an aperture 15 with the underside of floor surface 33 resting on supports 19. When so positioned, the removable blanking plate 31 blanks the aperture 15 completely, and the floor surface 33 is flush with the floor surface 11 of the access tile 3 Referring to Figures 10 and 11, another module comprises an access frame 41 and a drop-in blanking plate 43. The access frame 41 is of sheet metal construction and comprises a planar outer periphery 45 which bounds a rectangular access opening 47, two folded down side walls 49 bounding the long margins of the opening 47, and two folded down ends 51.

The access frame 41 is dimensioned to be received in an aperture 15 with the underside of the periphery 45 resting on supports 19, and optionally screwed in place.

When so fitted, the acccss frame 41 provides a permanent access opening allowing relatively large access for a plurality of cables to the underfloor void.

The drop-in blanking plate 43 is of sheet metal form and comprises a planar top tloor surface 53 and two folded down ends 55. A V' shaped reinforcing sheet 57 is located underneath the floor surface 53, extending between the ends 55. A central hole 59 is provided in the floor surface 53. The drop-in blanking plate 43 may be used to temporarily close the access opening 47 of access frame 43 by resting the floor surface 53 on the periphery 45 of frame 43. The central hole 59 may receive a finger of the installer, or a suitable tool to enable the blanking plate 43 to be more easily remove d.

Referring to Figures 12 and 13 a fur her module comprises another access frame 61 and another drop-in blanking plate 63.

The access frame 61 is of similar construction to frame 41 described above except that the access aperture 67 in this example only extends for about half of the width of the frame 61. The other half of the frame 61 comprises a planar floor surface 69 supported underneath by a T-shaped reinforcing bar 71, and a V shaped support sheet 73. Blanking plate 63 is as per blanking plate 43 but dimensioned to fit the smaller access aperture 67 to temporarily close the access aperture 67.

This arrangement allows access for a smaller number of cables but assists with containing the air flow and temperature control in the underfloor void.

With additional reference to Figure 14, the corner clamp 7 is of sheet metal construction cut to form an oblong base 75, an upwardly extending stem 77, a laterally extending cross piece 79 and two upstanding fingers 81, one at each end of the cross piece 79.

The stem 77 is inclined forwardly such that the base 75 and the fingers 81 do not occupy the same plane. The tops of the fingers 81 are bent backwardly to form a rear locating channel 83 at the top of the corner clamp 7. The distal ends of the cross piece 79 are bent forwardly so that the distal ends of the cross piece 79. and the fingers 81, and therefore the ends of the channel 83, are at about 45° to the plane of the remainder of the cross piece 79 and the base 75. Two diametrically opposed bolt holes 85 are formed in the base 75.

In use, with reference again to Figure 1, the bent part of the fingers 81 located onto the bent under part of the foot 13 of the access tile 3 so that part of the foot 13 is received in the locating channel 83. The base 75 is then located in the corner of the tile 3, at 45° to the side and end of the tile 3. Clamping means comprising a suitable intermediate bracket 87 with a clamping bar 89 is used to secure the corner clamp 7 to an upright 5 by way of the clamping bar 89 extending around the rear of the upright 5, and through the intermediate bracket 87, with the threaded ends of the clamping bar 89 extending through the bolt holes 85 in base 75 and being secured thereto by way of suitable nuts and washers.

Referring to Figure 15, intermediate clamp 9 is of similar construction to corner clamp 7, but the cross piece 79 is straight and not bent. With reference to Figure 1, the intermediate clamp 9 is used to clamp two adjacent tiles 3 to an intermediate upright 5, again using clamping means comprising a suitable intermediate bracket 87 and claniping bar 89.

Referring to Figure 16, an equipment clamp 91 is of sheet metal construction and comprises an elongate base 93 flanked by upstanding side walls 95 so as to be of U' shaped transverse cross section. One end of the base 93 comprises an upstanding leg 97 which terminates in a rearwardly directly platform 99, parallel to the base 93.

The leg 97 and platform 99 are also of U' shaped transverse cross section.

The base 93 is provided with an elongate slot 101 extending along most of its length.

The platform 99 is provided with an aperture 103 through which a foot assembly 105 extends. The foot assembly 105 comprises a threaded shaft 107, an upper knurled wheel 109, an intermediate nut 111 and a lower foot 113. The nut 111 abuts the underside of the platform 99 and can be adjusted along the length of the shaft 107 such that the foot 113 is in contact with the ground.

In use, a bolt or bolts may be extended through the slot 101 and into preformed holes formed in the access tile 3, or in one of the modules. The base 93 of equipment clamp 91 can therefore be secured to the access tile 3. Part of a piece of equipment such as an electrical cabinet or the like is then located between the upper face of the platform 99 and the underside of the knurled wheel 109, and the wheel 109 screwed down onto that part of the equipment to sandwich it between the platform and wheel 109. This provides a means to clamp the equipment to the access tile to resist tipping or movement of the electrical cabinet, without drilling or a more complex clamping arrangement. The elongate slot 101 allows the position of the cabinet clamp 91 to be easily adjusted relative to the access tile 3.

Referring to Figure 17, a further module comprises a storage box 111 dimensioned to be received in one of the apertures 15 of the access tile 3. The box Ill comprises a cuboidal sheet metal container 113, the upper open end of which is secured to a modified version of the access frame 41 described above which enables the box 111 to be screwed to the access tile 3. A lockable sheet metal lid 115 is also provided. The lid 115 comprises a rear lug 117 that is received in a slot formed in one end of the container 113, with a locking tab 119 being arranged to be received in a slot 121 formed in the other end of the container 113.

Referring to Figure 1 S. a brush strip 131 comprises a mounting strip 133 and a horizontally projecting elongate brush 135 extending along the length of the strip 133.

The mounting strip 133 is adapted to be mounted inside the periphery of access frame 41 such that the brush 135 extends partially across the opening. A similar brush strip 13 1 can bc provided on an opposite part of the access frame 41 such that the brushcs 135 close, or partially close the apcrturc, but still allow cables to extend through the access tile 3 into the underfioor void. The brushes 135 can assist in preventing air and heal transfer between the underfioor void and the room in which the raised floor is located, to facilitate cold aisle/hot aisle best practices. It will be appreciated that the dimensions of the brush strip 131 can be adapted to fit whatever size of opening is required.

Referring to Figure 19 an attachment 141 for an access tile 3 coniprises a pair of spaced apart elongate hangars 143 the upper ends of which are bent to form hooks 145 Ihat hook onto part of Ihe foot 13 of, and hang down below, access tile 3. An r' shaped cross section cross bar 147 is formed from sheet metal bent about a central fold line 148, and attached to the lower ends of the hangars 143 and a cable support which in this example comprises a generally planar cable support tray 149 mounted on the cross bar. The hangars 143 and cross bar 147 are each provided with a plurality of slots that enable the cross bar to be attached to the hangars 143 in various different positions.

In use, the cable support tray 149 provides support for any cables that pass through the access tile 3 into the underfloor void.

A further module may be provided comprising a cable demarcation point, that is, an electrical or data terminal or connection for terminating a given cable routed to the cable demarcation point. Such a module, for example, allows a cable in the underfloor void to terminate at the cable demarcation point, and then a further cable above the raised floor to be connected.

The above described examples are primarily formcd from sheet metal, and Ihis may be sheet steel for example. The metal may be corrosion treated, painted, and/or powder coated as required. The thickness of sheet can be selected to give the required strength for each component.

The access tiles 3 described above can be designed to be direct replacements for existing tiles used in raised flooring. Thus, the access tiles 3 can be produced in standard sizes accordingly. Examples of such sizes would be 600mm by 600mm, 800mm by 800mm and 1000mm by 1000mm. The depth of such tiles can be varicd to suit the load and space requirements in a particular scenario, but as an example only might be around 40mm. Likewise the size and shape of the access apertures 15 and/or the openings in the modules can be varied accordingly. As examples only, a large aperture/opening could be 410mm by 110mm, whilst a smaller aperture/opening could be 200mm by 110mm.

It will be appreciated that the above described access tile assembly I does not require any drilling or cutting in situ, even when alterations are required. The modules are secured by any suitable fixings which may simply be screws, or could be via snap fit or clip type connectors. The modules can therefore be removed and replaced relatively easily. For example if a blanking plate is used, and then subsequently it is required to have cables in that area, the blanking plate can be removed and replaced with an aperture plate. Any combination of modules can be provided and used as required. The access tile assembly 1 may be supplied as a kit with a predetermined number and/or combination of modules.

Likewise the access tiles 3 can be securely fixed to the raised flooring substructure without the need for any drilling, cutting or welding. Likewise any electrical equipment can be secured on top of the access tiles 3 without any alterations to the flooring substructure, and without any drilling into the underlying concrete floor or substrate.

Furthermore, the above described components arc of a robust construction with reinforcements that substantially strengthen the components, without overly increasing the bulk, weight or complexity. in particular, each floor surface is reinforced.

It will be appreciated that features of the access tile assembly as described above, and as shown in the drawings, may be present in any combination or configuration required.

Claims (24)

1: CLAIMS 1. An access tile assembly for a raised floor, the access tile assembly comprising at least one access tile comprising a peripheral support frame the underside of which is adapted to rest on vertical stands of the raised floor to form a void beneath the access tile, the topside of which comprises a floor surface for supporting items on the access tile, the support frame defining a plurality of access apertures within the periphery of the frame, the apertures enabling access to the void beneath the access tile in use, each aperture being provided with at least two opposed supports, the (0 assembly further comprising a plurality of removable modules, at least one module being provided for each aperture, each module being adapted to be received in an aperture and to rest on the supports, each module comprising at least one of: a planar blanking plate to close the aperture, the blanking plate comprising a planar floor surface; and IS an aperture access plate comprising an opening to enable access to the void CV) beneath the access tile in use.

If')

2. An access tile assembly according to Claim I wherein the supports arc 0 recessed below a top plane of the access tile, each module comprising a planar top 0) 20 floor surface such that when a module is received in an aperture, the planar top floor CSJ surface of the module is flush with the plane of the floor surface of the access tile.

3. An access tile assembly according to Claim I or Claim 2 wherein the opening of the module comprising the aperture access plate extends substantially the length of the plate, from a position adjacent one end of the module to a position adjacent the other end of the module.

4. An access tile assembly according to any foregoing claim wherein a module is provided comprising a partial aperture access plate, comprising an opening extending only partially the length of the plate, the remainder of the plate comprising a planar floor surface.

5. An access tile assembly according to any foregoing claim I wherein each aperture access plate further comprises a blanking plate dimensioned to be received in, and to blank the opening, the blanking plate comprising a planar floor surface.

6. An access tile assembly according to any foregoing claim wherein a module is provided comprising a storage box dimensioned to be received in an access aperture.

7. An access tile assembly according to Claim 6 wherein the storage box is lockable.

8. An access tile assembly according to any foregoing claim wherein the floor surface of each module comprises reinforcement, on the underside of the floor surface.

9. An access tile assembly according to Claim 8 wherein the reinforcement comprises an elongate reinforcing bar extending along at least part of the floor surface.

10. An access tile assembly according to Claim S or claim 9 wherein the CV) reinforcement comprises a reinforcing sheet of V' shaped transverse cross section which extends along at least part of the underside of the floor surface, the outer If') margins of the sheet being secured to the floor surface, with the apex of the V spaced 0 from the floor surface. 0)20

CSJ

Ii. An access tile assembly according to any foregoing claim wherein a brush strip is provided along at least one margin of the opening of the (partial) aperture access plate, the brush strip comprising a laterally projecting brush that extends along a margin of the opening and projects across the opening so as to partially close the opening, but to deflect around any cables or other objects extending through the opening.

12. An access tile assembly according to any foregoing claim wherein a comet clamp is provided comprising engagement means operative to engage a corner of the access tile, and clamping means being operative to secure the corner clamp to an upright of the raised floor.

13. An access tile assembly according to Claim 12 wherein the corner clamp is of sheet metal construction and comprises a base and engagement means upstanding from the base and comprising an upper channel comprising laterally spaced apart ends that are at 45° to the base when viewed in plan, the channel engaging the underside of the access tile in use, the clamping means extending around the upright of the raised floor and being secured to the base.

14. An access tile assembly according to Claim 12 or claim 13 wherein the clamping means comprises a separate bracket adapted to engage the corner clamp.

15. An access tile assembly according to any of claims 12 to 14 wherein an intermediate clamp is provided comprising engagement means operative to engage a margin of the access tile, and clamping means operative to secure the intermediate clamp to an upright of the raised floor.

16. An access tile assembly according to Claim 15 wherein the intermediate clamp is of sheet metal construction and comprises a base and engagement means upstanding from the base and comprising an upper channel comprising laterally spaced apart ends CO that are at parallel0 with the base when viewed in plan, the channel engaging the v underside of the access tile in use, the clamping means extending around the upright LI') of the raised floor and being secured to the base.0') 20

17. An access tile according to claim 13 or any of claims 14 to 16 when dependent C%J on claim 13, wherein the ends of the channel are sufficiently spaced apart that each end of the channel can engage a respective access tile, when the clamp is in use with adjacent access tiles.

1 8. An access tile assembly according to any foregoing claim wherein a module is provided comprising a cable demarcation point.

19. An access tile assembly according to claim 18 wherein the cable demarcation point comprises an electrical or data terminal or connection for terminating a given cable routed to the cable demarcation point.

20. An access tile assembly according to any foregoing claim wherein a module is provided comprising an attachment for support cables beneath the access tile, the attachment comprising a cable support attached to and spaced below the access tile.

21. A raised floor comprising an access tile assembly according to any of claims I to2O.

22. A clamp for use with an access tile assembly of any of claims I to 20, the S clamp being of sheet metal construction and comprises a base and engagement means upstanding from the base and comprising an upper channel comprising laterally spaced apart ends which engages the underside of the access tile in use, the clamping means extending around the upright of the raised floor and being secured to the base.

23. A clamp according to claim 22 comprising a corner clamp wherein the laterally spaced apart ends are at 45° to the base, when viewed in plan.

24. A clamp according to claim 22 or claim 23 wherein the clamp comprises an intermediate clamp where the laterally spaced apart ends are parallel with the base, when viewed in plan.CO25. An access tile assembly substantially as described herein with reference to any If') one or more ofthe accompanying drawings. 0) c'J