This invention relates to trunking for use in a raised floor and to a raised floor incorporating said trunking.

Generally, trunking is buried in a concrete floor screed below a raised floor. Where such trunking is inadequate to accommodate additional cables or is not provided it is conventional to fix trunking on the concrete floor and cover the trunking with a raised floor. This latter arrangement is widely employed although this results in the finished floor level being relatively high. As shown in UK-A-2 202 246, the minimum finished floor level is determined by the combined depth of the trunking and the raised floor plus a small allowance for irregularities in the existing surface and clearing other services. This level can be unacceptable particularly where the remaining distance from the raised floor to the ceiling is less than the minimum permitted by planning regulations.

It is an object of at least preferred embodiments of the present invention to reduce the minimum finished floor level. According to the present invention there is provided trunking for use in a raised floor, which trunking comprises a channel portion including a base bounded on either side by two upwardly extending walls, each of which is provided with an outwardly extending support section comprising a flange which extends outwardly from each upwardly extending wall for supporting a cover, characterized in that means are provided below each said flange which means, in use, rest on floor pedestals and support at least part of the weight of said channel portion.

In contrast to prior proposals the volume of trunking available for the passage of cables extends into the thickness of the floor. Although this distance may be quite small it can represent the difference between a building being suitable for commercial use and of no significant work, particularly where the floor itself cannot be channelled.

The means could simply comprise a second flange extending outwardly from each upwardly extending wall. Alternatively, it could comprise a downwardly extending portion which extends downwardly from the flange. Alternatively the means could comprise a box section having a lower wall which, in use, rests on loor pedestals and an upper surface which supports the flange, for example directly or via a spacer.

Preferably, at least one of said support sections comprises a flange which extends away from the top of an upwardly extending wall, a downwardly extending portion which extends downwardly remote from said upwardly extending wall, and a return portion which extends inwardly from the bottom of said downwardly extending portion

The upwardly extending wall, flange, downwardly extending portion and return portion may be formed as an integral structure.

If desired, the support section may also comprise a second downwardly extending portion which extends downwardly from the inner end of said return portion adjacent said upwardly extending wall. Advantageously, a second return portion extends inwardly from the bottom of said second downwardly extending portion adjacent the base of said trunking.

Preferably, the second downwardly extending portion and/or the second return portion are spot-welded

to the upwardly extending wall and/or the base respectively.

Preferably, said trunking further comprises additional means of support. Such means may comprise threaded studding which is threadedly connected to the base of said trunking.

Advantageously, said trunking further comprises one or more channel sections which may be detachably mountable on the base or may be permanently secured thereto.

Conveniently, said channel section(s) are secured to said base by said additional means of support.

Preferably, said channel section(s) include at least one outwardly extending lip for providing support for said cover.

Advantageously said trunking also includes a cover.

Preferably, the cover is removably secured to said flanges which extend outwardly from each of said upwardly extending walls of said channel portion.

The present invention also provides trunking for use in a raised floor for enabling individual communication between separated areas of three or four lengths of converging trunking, characterized in that said trunking comprises a removable section which can be placed in position after a first cable has been laid in a first area communicating with all said converging lengths of trunking and which can support and guide second and third cables in second and third areas which are separated from one another and from said first area.

This arrangement differs significantly from the prior art, for example PCT/AU 87/00356, in that the whole of the first area can be carcassed in all directions before the removable section is fitted. This

is a considerable advantage when handling data cables which are relatively delicate and should not be subjected to sharp bends, or heavy power cables which are extremely unwieldy. Advantageously, said trunking enables individual communication between separated areas of four lengths of trunking converging in substantially the same plane at right-angles to one another, and is characterized in that said removable section is in the shape of a cruciform.

Preferably, said cruciform has four arms each having two channel sections thereon which converge onto a cross-over area.

Preferably, said cross-over area is provided with a removable bridge section.

Advantageously, said cross-over area is provided with two bridges which are so arranged that, in use, cables in said second areas can communicate with one another without passing over a bridge and cables in said third area can communicate with one another by passing over said bridges.

Preferably, said bridges are each provided with upwardly extending barriers.

Advantageously, said trunking includes a cover.

The present invention also provides a raised floor part of which is formed by trunking in accordance with the invention.

Preferably, the upper surface of the trunking is flush with the surface of the remainder of the raised floor.

Advantageously, the trunking is supported by pedestals which are also used to support adjacent panels. Preferably, the trunking is provided with

further supports.

For a better understanding of the invention reference will now be made, by way of example, to the accompanying drawings, in which:-

Figure 1 is a cross-section through one embodiment of trunking in accordance with the invention incorporated in a raised floor;

Figure 2 is an exploded perspective view of the trunking shown in Figure 1;

Figure 3 shows four lengths of trunking as shown in Figure 2, converging on a second embodiment of trunking in accordance with the invention which is shown in exploded form with two alternative removable bridge units;

Figure 4 is a section taken on line IV-IV of Figure 3 but with the trunking fully assembled using the removable bridge unit shown at the top right of Figure 3 but with the trunking fully assembled using the removable bridge unit shown at the top right of Figure 3; and Figure 5 is a cross-section through a detail of an alternative embodiment of trunking to that shown in Figures 1 and 2.

Referring to Figure 1, there is shown a raised floor which is generally identified by reference numeral 1. The raised floor 1 comprises a plurality of square panels which are approximately 600 mm x 600 mm. Each panel is supported at each of its corners by a floor pedestal, the height of which can be adjusted. Panels 2 and 3 are supported by floor pedestals 4 and 5 which also serve to support trunking 6.

The trunking 6 comprises a channel portion 7 and a cover 8. The channel portion 7 comprises a base 9, bounded at its sides by two upwardly extending walls 10 and 11 respectively. Flanges 12 and 13 extend outwardly from the two upwardly extending walls 10 and 11 and

terminate adjacent flanges 12a, 13a which extend inwardly from downwardly extending portions 14 and 15. Return portions 16, 17 extend inwardly from the bottom of the downwardly extending portions 14 and 15. A second downwardly extending portion 18, 19 extends downwardly from the inward extremity of return portions 16 and 17 respectively and terminates in a second return portion 20, 21 which extends under and reinforces the base 9.

The downwardly extending portions 18, 19 and the return portions 20 and 21 are spot-welded to the upwardly extending walls 10 and 11, and the base 9 of the channel portion 7 respectively.

The base 9 is further supported by threaded studding 28, 29 which threadedly engages threaded bushes 25, 27 welded to the base 9.

Two channel sections 22 and 23 are welded to the base 9.

The top of each channel section 22, 23 is provided with an outwardly extending lip 30, 31 which gives further support to the cover 8.

The cover 8 is secured to the flanges 12a and 13a by a multiplicity of screws 32.

During fixing the floor pedestals are first set out at the required centres and then levelled. The trunking 6 and the panels are then simply laid in position. In order to install cables screws 32 are removed and cover 6 lifted to reveal four separate and distinct areas 33, 34, 35, 36 for the reception of cables. It will be noted that the combined length of downwardly extending portion 14 and the thickness of the cover 8 is equal to the thickness of the panels 2 and 3.

This ensures that the top of the cover 6 is flush with the upper surface of the panels 2 and 3. Furthermore, almost one half of the volume available for cables is within the thickness of the panels 2 and 3.

As can be seen in Figure 2, end 37 of trunking 6 is terminated by a member 38 having a base 39, an upright 40 and a top member 41 which finishes immediately below the underside of the surrounding panels. The member 38 is secured to the trunking 6 via a splice plate 42. The splice plate 42 can also be used for joining adjacent lengths of trunking. The trunking 6 and the channel sections 22, 23 are provided with knockouts, for example 43, at regular intervals to facilitate the entry and exit of cables.

Referring now to Figure 3, four lengths of trunking 6a, 6b, 6c and 6d are shown converging at right-angles to one another. Each section of trunking 6a, 6b, 6c and 6d is divided into four areas 33, 34, 35 and 36 by means of channel sections. For the purpose of this description areas 33 and 36 are intended to accommodate computer data cables, area 34 power cables, and area 35 telephone cables. One of the problems associated with this arrangement is designing trunking which is capable of separating the power cables, the computer data cables and the telephone cables from one another whilst enabling full communication between equivalent areas in each section of trunking 6a, 6b, 6c and 6d. To solve this problem trunking is proposed which comprises a square pan 150 which has a bottom 151, side walls 152, and flanges 153. As can be seen in Figure 3, the flange 153 is arranged to lie flush with the bases 9a, 9b, 9c and 9d of the trunking 6a, 6b, 6c and 6d which are all in the same plane. Computer data cables in areas 33 and 36 of each trunking 6a, 6b, 6c and 6d can thus communicate with one another and with corresponding areas in other trunking 6a, 6b, 6c and 6d by simply dropping down the side walls 152 and along the bottom 151 of the pan.

The trunking also comprises a removable section 100 which comprises a base plate 101 in the shape of a cruciform. The base plate 101 comprises four arms 102a, 102b, 102c and 102d. Two channel sections are mounted on each arm 102a, 102b, 102c and 102d and converge on a cross-over area 106. Channel sections 122a and 123a are mounted on arm 102a. The width of channel sections 122a and 123a is equal to the width of channel sections 22a and 23a. However, the depth is slightly less. As better shown in Figure 4 a support 154a extends downwardly from the free extremity of arm 102a and rests on the flange 153. Arms 102b, 102c and 102d are provided with corresponding supports 154b, 154c and 154d respectively. These supports 154a, 154b, 154c and 154d are optional but can prove useful for increasing the distance between the base plate 101 of the removable section and the bottom 151 of the pan 150.

Each channel section is provided with an outwardly extending lip, for example 130a, 131a for supporting a cover 108 as shown in Figure 4.

Four threaded sleeves 155 extend upwardly from the bottom 151 of the pan 150. Each threaded sleeve 155 has a threaded bore which contains a threaded rod 156 which can be raised or lowered by rotation relative to its sleeve as desired. The top of the threaded sleeve 155 is also threaded to receive a screw 157 for retaining the cover 108. The threaded screws 155 and the threaded rods 156 thus support the cover 108 from the oversite whilst the threaded sleeves 155 also act to locate the removable section 100. If desired nuts may be provided on the threaded rods 156 to further support the pan 150 which is screwed to the trunking 6a, 6b, 6c, 6d by screws (not shown).

The cross-over area 106 comprises a removable bridge unit comprisingtwo bridges and associated barrier

walls. Alternative embodiments of removable bridge units 158', 258' are shown to the left and right at the top of Figure 3.

When removable bridge unit 158 is placed in cross-over area 106 channel section 122a communicates directly with channel section 122b, 122c and 122d. The bases of each of channel sections 122a, 122b, 122c and 122d are all at the same level. It will be noted that cables can be placed in channel sections 122a, 122b, 122c and 122d prior to the removable unit 158 being positioned.

From closer inspection it will be appreciated that this arrangement allows the computer data cables in areas 33 and 36 to communicate freely whilst being at all times separated from the remaining cables.

Channel section 123a communicates with channel sections 123b, 123c and 123d via a first bridge 158. The first bridge 158 comprises a first side wall 159, a platform 160 and a second side wall 161. The platform 160 is also bounded by two barrier walls 162 and 163 which extend upwardly and finish flush with the outwardly extending lips 130a and 131a.

In a similar manner channel section 123b communicates with channel sections 123a, 123c and 123d via a second bridge 164.

The second bridge 164 comprises a first side wall 165, a platform 166 and a second side wall 167. The platform 166 is also bounded by two barrier walls 168 and 169 which extend upwardly and finish flush with the outwardly extending lips 130a, 131a.

On closer inspection it will be appreciated that this arrangement allows the telephone cables in areas 35 to communicate freely whilst being at all times separated from the remaining cables. It will be noted that the barrier walls 162

and 168 are joined to fully separate the areas.

It will be appreciated that the pan 150, whilst highly desirable, is not absolutely essential.

The fact that the section 100 is removable greatly facilitates installation since computer data cables or heavy power cables can simply be laid in position and removable section 100 subsequently dropped into place.

An alternative removable bridge unit 258' is shown at the top right of Figure 3. The removable bridge unit 258' comprises two bridges.

The first bridge is defined by a first side wall 259, a platform 260, and a second side wall 263.

The platform 260 is also bounded by two barrier walls 261 and 262 which extend upwardly and finish flush with the outwardly extending lips 130a and 131a.

The second bridge comprises a first side wall

264, a platform 265, and a second side wall which is defined by an extension of side wall 263. The platform 265 is also bounded by two barrier walls, viz: barrier wall 266 and an extension of barrier wall 262.

Whilst this arrangement ensures separate and distinct communication between areas 32 and 34 in all directions it has the disadvantage that the area 34 cannot be carcassed in all four directions before the removable bridge unit 258' is positioned.

Various modifications to the trunking shown in Figures 1 and 2 are envisaged, for example the channel portion 7, the flanges 12, 12a; 13, 13a; downwardly extending portions 14, 15 and return portions 16, 17 could be formed in a single extrusion. Alternatively the channel portion 7 could be provided with flanges 12 and 13 and box sections disposed below the flanges 12, 13 and adjacent the upright walls 10, 11. Such box sections could conveniently be welded to their associated flange

and/or upright wall. If desired the first bridge 158 and the second bridge 164 may be fixed in the centre of the removable section 100. However, this arrangement has the disadvantage that the cables have to be threaded under the first bridge 158 and/or the second bridge 164.

Figure 5 shows part of a length of trunking which is similar to the trunking shown in the previous figures. In particular, the trunking which is generally identified by reference numeral 6' comprises a channel portion 7' comprising a base 9 bounded at its sides by two upwardly extending walls only one of which 10' is shown. Flange 12' extends outwardly from the upwardly extending wall 10' . A box section 200 having an upper portion 201 parallel to to the flange 12' , a first side wall 202 adjacent the upwardly extending wall 10', and a second side wall 204 extending downwardly remote from the first side wall 202 and a lower wall 203, rests on the floor pedestal 4' . The box section 200 is welded to a spacer 208 and the upwardly extending wall 10' by welds 205, 206 as shown. The flange 12' supports a cover 8' , the upper surface of which is flush with the top of ad acent panels, for example panel 2'.

The panel 8' is screwed to the flange 12' by screws 32' . It will be appreciated that the thickness of the spacer 208 can be varied according to the thickness of the panel 8' .