GB2193851A - Cable trunking - Google Patents

Abstract

Ducting for underfloor cable trunking comprises an open-ended tray (10) with side walls (12, 14) and with two higher dividing walls (16, 18), and a supporting strap 66 to hold two such aligned trays immediately below a floor panel (48). The walls (16, 18) have removable panels (38) to enable cables to cross over into the central channel between these walls. The removable panel (38) may be bent over (Figs 2 & 5) and/or removed by a hand tool having a body (42 Fig. 3) and a groove (44) engageable with the panel (38). The trays are carried by straps (60 Fig. 4) under the floor. A support (92 Figs 5 & 6) may be provided for cables as they are lead across the top of the side walls (12, 14). A T-juncton may be formed using two trays and bridging members (112, 114, Fig. 9) to lead cables from the inner channels over those in the outer channels. <IMAGE>

Description

SPECIFICATION Trunking Field of invention This invention concerns cable trunking particularly for installation within raised floors to enable wires and cables to be conveyed safely below floors in shops offices and the like.

Background to the invention It is known to provide ducting below floor level to convey services such as electical supply cables, telephone cables, data highway cables in computing installations and the like from one part of a room to another and from one part of a building to another.

It is an object of the present invention to provide an improved design of ducting for assembly into elogate lengths of cable trunking which are readily modified during assembly and after installation to accommodate bends and T-junctions and the like to provide for tap-offs and cross-over junctions.

Summary of the invention According to one aspect of the present invention ducting for forming underfloor cable trunking by cooperation with the underside of the flooring, comprises: 1. a parallel sided open topped tray having side walls but open at opposite ends and having two equally spaced apart intermediate dividing walls extending therealong parallel to the two side walls thereby to define three parallel channels along which cabling can be run, the height of the intermediate dividing walls being greater than the height of the side walls and the open ends of the tray allowing it to be linked in an aligned manner to other such trays to form longer channels along which the cabling can run;; 2. support means adapted to carry aligned trays immediately below flat flooring panels so that the upper edges of the intermediate dividing walls make contact with the underside of the paneis to form a closed box-like section; and, 3. sections of at least the intermediate dividing walls being in the form of removable panels which when removed define apertures to enable cables from an outer channel to cross over the central channel at a junction between a length of the trunking extending in one direction and another length of trunking extending at an angle to the first, into and along which cables from the first are to run.

In a preferred embodiment the open topped tray and the floor panels are at least in part formed from metal, typically galvanised sheet steel.

Preferably the removable panels in the said intermediate dividing walls adjoin the top edge of the wall and can be removed or simply bent down to leave an opening in the upper edge of the wall through which the cables can extend.

According to a preferred feature of the invention there is provided a tool for gripping the upper edge of a removable panel section of an intermediate dividing wall, to facilitate the bending of the panel section about a line parallel to the upper edge of the wall for removing the panel as by continual bending about the said line or for simply bending the panel about the said line.

Preferably the panels are defined by lines of perforations or weakness parallel and perpendicular to the upper edge of the wall.

The tool may conveniently comprise an elongate member having a groove in its underside for fitting over the upper edge of the wall and a handle section thereabove by which the tool can be gripped and twisted to one side or the other to effect the breaking or bending.

The invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 is a perspective view from above of part of one length of open topped ducting which can cooperate with the underside of flooring panels to form cable trunking, in accordance with the invention; Figure 2 is a perspective view to an enlarged scale of an intermediate dividing wall of the ducting with a section bent down; Figure 3 is a perspective view of a tool for bending down and/or breaking off segments of the walls of the ducting; Figure 4 is an end view of the ducting of Figure 1 shown in position below floor panels and forming cable trunking; Figure 5 is a perspective view of the ducting element of Figure 1 showing how a connection can be made to multiple way socket in the central channel; Figure 6 is a perspective view of a cable support;; Figure 7 is a perspective view of the ducting support used in Figure 4; Figure 8 is a perspective view of a bridge member for allowing cabling to extend over channels at a Junction; and Figure 9 is a perspective view of a completed Junction.

Description of the drawings In Figure 1 there is shown a section of ducting generally designated 10 in the form of a shallow open topped parallel sided tray, having two opposed parallel side walls 12, 14 and two parallel intermediate dividing walls 16, 18 which are approximately twice the height of the side walls 12, 14 measured from the base 20. The intermediate walls 16, 18 are perforated with relatively large regularly spaced apertures of equal size as denoted by reference numerals 22 and 24 and are further formed with lines of weakness (typically in the form of lines of miniature perforations or in dentations) as at 26, 28 and with half severed cuts 30, 32 in 16; and 34, 36 in 18, defining rectangular panels which can be removed by folding down along the line of weakness 26 or 28 respectively.

Figure 2 shows one such panel 38 folded down from the intermediate wall 22.

If the panel 38 is to be completely removed it can be bent backwards and forwards about the fold line 40 until it snaps off.

Figure 3 shows a hand tool for achieving the bending about the fold line 40. This comprises a metal body 42 adapted to be gripped between thumb and fingers, having a deep groove 44 in its lower edge for engaging over the upper edge of a weakened panel such as 38. When so positioned the tool can be tilted one way and then the other to break the lines of weakness 30, 32 and then bent to the left or the right as required, or simply twisted to remove it completely, as required.

Each tray like length of ducting 10 can be fitted end to end with other similar lengths to provide longer lengths of underfloor trunking and the manner in which the lengths 10 are supported below floor panels such as 46, 48, 50 is shown in Figure 4 and Figure 7. The cross-section through a typical office floor of Figure 4 shows the rigid metal panels 46, 48, 50 supported at their corners on adjustable legs 52, 54 which include feet 56, 58 and upper platforms 60, 62 respectively, the latter being screwthreadedly adjustable relative to the feet 56, 58 to allow the adjustment of the height of the platforms and therefore the floor panels, above the subfloor, 64. This adjustment also allows any unevenness in the subfloor to be accommodated.

The ducting elements such as 10 are carried by inverted bridging straps 66, one of which is shown in more detail in Figure 7. The extreme ends 68, 70 are trapped between the panels 46, 48 etc and the platforms 60, 62 of an adjoining pair of adjustable legs 52, 54 and the stepped region 72 of each strap 66 is displaced below the underside of the panels 46, 48 etc, by its intermediate legs 74, 76 to a depth just equal to the height of the intermediate dividing walls 16, 18 so that the two dividing walls 16, 18 form with the base of the ducting tray 20 and the underside of the floor panels, a box section 78. The two other channels 80, 82 defined between the side walls 12, 14 and the dividing walls 16, 18 respectively, are separated completely from the inner box section channel 78, but are not completely encased as is the central channel 78.

The central channel 78 is thus suitable for electrical supply cables and the like whilst the outer channels can carry telephone cables, data-communication cables, intercom cables and the like.

It will be seen that the trunking system forms an integral part of the flooring system and in general must be laid at the same time as the legs 52, 54 etc are positioned on the subfloor and adjusted for height, since the thickness of the plate member forming the ends of the step support 66 must be taken into account in assessing the height of the platforms 60, 62 etc. However, it will be seen that the floor can be laid without the need for any cabling to occur pro tem, and the wiring contractors can independently work on site after the floor is laid and gain access to the trunking by simply lifting the floor panels such as 48 overlying the main lengths of trunking and return these panels after the cabling has been completed.

The method by which electrical power can be distributed to sockets or appliances en route along the trunking is illustrated in Figure 5. Here multiway socket assemblies 84 are located at intervals along the length of the central channel 78 and plugs and flying leads 86, 88 connected to the socket assembly in manner known per se.

Access to the central channel 78 is achieved by bending down a panel such as 38 (see Figure 2). The bent down panel forms a platform for a clip 90 for securing the flying lead to the trunking.

As shown in Figures 5 and 6 a guide plate and cable support 92 is provided in alignment with the opening formed by bending down the panel 38, and this is secured to the outer wall 12 by spring clips 94,96 (see Figure 6). The upper edge of the support 92 is cut away to form three slots 98, 100, 102 into which one or more flying leads from the trunking can be passed. As shown there is one slot for each of the channels in the trunking.

If semi rigid, coated cable is employed or sleeving of steel or plastics is provided for the cables, the effect as shown in Figure 5 can be readily obtained, where cabling for a particular work station or the like in an office or workshop can be laid out between the underside of the flooring panels and the slots 98, 100 etc in a support plate 92, with minimal disurbance. Indeed the opening to permit the last of the cable 88 from the central channel can be formed even after the trunking and the flooring panels have been put in place, by simply lifting the relevant flooring panels, and using the tool of Figure 3, bending over the relevant section 38 and inserting a plug 86 into the nearest socket assembly such as 84.

A telephone cable 104 is shown leaving the nearside channel 80 through another of the sockets 98.

Where a T-junction is required it is simple to construct using two ducting elements at right angles, together with a member of the bridging elements such as shown in Figure 8.

The purpose of this is to provide a brige over the central and nearside channels 78, 80 for cabling from the remote channel 82, into the corresponding channel 106 of the orthogonal ducting element 108.

Thus one such bridge element 110 is fitted over the knocked down nearside central dividing wall 16 and the nearside outer wall 12 whilst two aligned elements 112, 114 bridge the central and nearside channels 78, 86 respectively. The downtail flaps 38, 38' and 38" provide the support at one end of each bridge element and one of the lines of holes 22 which align with holes 116 in the bridge element to allow quick-fix cage nuts to be inserted for securing the bridge elements in place.

A further bridge member 118 in the form of an inverted V-shape is provided for fitting over the low nearside outer wall 12.

The joint between the end of the element 106 and the side of the element 10 may be formed by simply abutting the end to the side, although adhesive or the like can be employed to improve the joint. In addition or alternatively brackets or fishplates (not shown) may be provided and screwed or riveted or otherwise secured to the walls of the ends and side walls of the two ducting elements.

It will be seen that the bridge members 110 and 114 form a tunnel through which cables running along the length of the channel 80 and the bridge member 112 form a tunnel through which electrical supply cables can run along the central channel 78.

If the bridge elements 110, 112, 114 are located at the end of the element 10, then the junction between the two elements 10 and 108 in an L-shaped junction. As shown the elements 10, 108 form a Junction.

It will be seen that the bridges can be fitted at any position along the length of a run of ducting elements either during initial construction or afterwards, both at a later stage of the installation or even after the installation has been completed for some months or years. In each case the procedure is the same, it merely being necessary to lift flooring panels and bend down the relevant panels 38, 38' etc and fit the bridge sections 110, 112, 114 etc to link to the new ducting element 108 which likewise can be fitted below the floor level by lifting the panels and adjusting the height of the support platforms to accommodate the strap supports such as 72 needed for the new ducting.

The ducting is particularly suited to being incorporated with distribution boxes let into floor panels and connected to the cabling, in the manner described in our copending patent application entitled ''Improvements in and relating to floor level distribution boxes".

Claims (7)

1. Ducting for forming underfloor cable trunking by cooperation with the underside of the flooring, comprising: a) a parallel sided open-topped tray having side walls but open at opposite ends and having two equally spaced apart intermediate dividing walls extending therealong parallel to the two side walls, thereby to define three parallel channels along which cabling can be run, the height of the intermediate dividing walls being greater than the height of the side walls, and the open ends of the tray allowing it to be linked in an aligned manner to other such trays to form longer channels along which the cabling can run; b) support means adapted to carry aligned trays immediately below flat floor panels so that the upper edges of the intermediate dividing walls make contact with the underside of the panels to form a closed box-like section; and c) segments of at least the intermediate dividing walls being in the form of removable panels which when removed define openings to enable cables from an outer channel to cross over the central channel at a junction between a length of the trunking extending in one direction and another length of trunking extending at an angle to the first, into and along which cables from the first are to run.

2. Ducting as claimed in claim 1 in which the open-topped tray and the floor panels are at least in part formed from metal, typically galvanised sheet metal.

3. Ducting as claimed in claim 1 or claim 2 in which said removable panel in each intermediate dividing wall adjoins the top edge of the wall and can be removed or simply bent down to leave an opening in the upper edge of the wall through which the cables can extend.

4. Ducting as claimed in any one preceding claim in which said removable panels are defined by lines of perforations or weakness parallel and perpendicular to the upper edge of the dividing wall.

5. A tool for gripping a removable panel of ducting as claimed in any preceding claim, comprising an elongate member having a groove in its underside for fitting over the upper edge of the removable panel and a body thereabove by which the tool can be gripped and twisted to one side or the other to effect the removal or bending.

6. Ducting for forming under floor cable trunking substantially as herein described with reference to, and as shown in, Figures 1, 2 and 4 to 9 of the accompanying drawings.

7. A tool for gripping a removable panel of ducting substantially as herein described with reference to, and as shown in, Figure 3 of the accompanying drawings.