CABLE MANAGEMENT SYSTEM AND METHOD OF LAYING CABLE

Abstract: A cable management system comprising an elongate wire frame tray for supporting cables lengthwise thereof, and flame-retardant plastics sheeting fixed to the base of the tray to form a resiliently deformable lining for cushioning the cables which lining also rigidifies the tray against bending about axes transverse to the length of the tray.

Description: CABLE MANAGEMENT SYSTEM AND METHOD OF LAYING CABLE This invention relates to a cable management system particularly, although not exclusively, for electrical cables, and to a method of laying cable. It is particularly useful at present for laying data transmission cables of the type CAT 5 to CAT 7, i.e. high speed data transmission cables. Cables which are to be laid along the flooring generally have their layout mapped out by painting a line along the floor, for example. For cables which need to be supported above ground, connected to a wall or suspended from a ceiling, they are often guided and supported by means of a metal tray, for example a tray whose base consists of metal plate. This smooth surface minimises bruising and provides electromagnetic screening, i.e. radio frequency interference shielding, in the case of power cables, but is bulky. Cables are typically bundled together using ties, for example plastics ties, but this in itself can lead to bruising. Laying cables directly on to flooring has led to problems of the ingress of moisture. Suspending cables on conventional trays has been expensive because of the need for strength together with the avoidance of irregular surfaces which would damage cable. These technical problems are recognised by international standards for the laying of high-speed data transmission cables and power cables; such standards typically specify the minimum spacing lengthwise for support members. A first invention is directed to the suspension of cables above ground, although it could also be used resting on the ground. The first invention provides a cable management system comprising an elongate wire frame tray for supporting cables lengthwise thereof, and flame-retardant plastics sheeting fixed to the base of the tray to form a resiliently deformable lining for cushioning the cables which lining also rigidifies the tray against bending about axes transverse to the length of the tray. This invention exploits the rigidity of the plastics sheeting against bending by connecting it to the wire tray to provide a rigid structure; this allows the tray to be made much lighter in weight than has previously been possible with metal trays, for example. Further, the resilient deformability of the plastics sheeting when impacted on its surface is exploited in the cushioning of the cables, avoiding the need for any metal plate or fine mesh in the base of the tray. Advantageously, the system further comprises a plurality of strips for bundling cables together or for encircling a single cable, at intervals along the cable or cables, and for adhering removably to respective ones of the cable-fixing members so as to hold the cable or cables on the sheeting with the cable or cables running generally lengthwise of the sheeting. This avoids the need for conventional plastics ties around the cables which have on occasions led to bruising of the cables. We have found that bundling cables with a strip of Velcro ® material at predetermined intervals along the cable is sufficient, and this facilitates the laying of the cable by connecting respective Velcro ® ties with the cable-fixing members which are preferably strips also of Velcro ® material. According to the CAT 5 to CAT 7 specifications, these fixing strips need only be spaced at 300mm intervals. The preferred plastics sheeting material is a twin-wall packing material sold in the UK under the Trade Mark TWINPLAST, which has lengthwise fluting, providing the required rigidity i.e. resistance to bending about transverse axes. A second invention is intended to improve the system for laying cables on a floor. It provides a cable management system comprising: pre-formed elongate pieces of flame-retardant sheeting, preferably of plastics, capable of acting as floor decking; means for fixing the sheeting pieces to a floor during installation; and, for each sheeting piece, a plurality of cable-fixing members, such as strips, each secured at intervals along its length. The thickness of the sheeting has the desired effect of lifting the cables above floor level; this can be enhanced if necessary by providing the floor-fixing means in the form of pads of a particular thickness; such pads would also help with levelling. The natural resilience of plastics sheeting, which is preferred, minimises bruising of the cable. Such plastics sheeting can also easily be colour coded so as to assist in the correct laying of cables particularly where many different channels are required to be laid in a building. In order that the invention may be better understood, preferred embodiments of the invention will now be described by way of example only with reference to the accompanying diagrammatic drawings, in which: Figure 1 is a broken away perspective view from above of two pieces of plastics sheeting embodying the second invention; Figure 2 is an end elevation of the plastics sheeting of Figure 1 , drawn to a larger scale and additionally showing extra features; Figure 3 is a perspective view of a partially open box section of plastics sheeting embodying the second invention; Figure 4 is an exploded perspective view from above and one side of a cable management system embodying the first invention, and comprising two pieces of plastics sheeting with corresponding pieces of tray; Figure 5 is a cross-sectional view of the assembled cable management system of Figure 4; and Figure 6 is an exploded perspective view corresponding to that of Figure 4, but showing additional features including compartments. A first example of a cable management system, particularly although not exclusively for high speed data transmission cables, is shown in Figures 1 and 2. As shown in Figure 1 , an elongate cable track for laying on a floor is formed by interconnecting rectangular pieces 1 end-to-end using connectors 3. Each connector 3, which is a plastics extrusion, has an H-shaped cross-section, with hook-shaped edges for assisting in retaining the sheeting once inserted. Each rectangular piece of sheeting 1 is formed in this example of a twin wall plastics packing material available in the UK under the trade name TWINPLAST. As shown in the end view in Figure 2, the sheeting has lengthwise fluting, to provide rigidity against bending about transverse axes. It is formed of a flame-retardant plastics, with an anti-static finish on each wall surface. In this example, the sheeting is 4mm thick, although thicknesses of 2mm to 6mm are envisaged. The fluting defines channels of width from say 2mm to 8mm. The fire-retardant twin wall decking may be fixed directly to the floor by means of 2mm thick fire-retardant double-sided self-adhesive pads 4 that can be fixed to the floor. These pads will take up any deviations in the surface level of the floor, in the space between the underside of the pads and the underside of the sheeting 1. The sheeting or decking 1 is edged using U-shaped channel members 5, optionally with sign printed information. Thus each sheeting piece has upper and lower walls 6,7 defining elongate channels 8 which are open at each end. For some purposes, such as radio frequency interference shielding, the plastics sheeting may be made conductive, either with the inclusion of microscopic conductive particles, or by the use of metallic foils or meshes or the like. The sheeting or the edging for the sheeting may be printed with the intended customer's requirements including its logo, or with information as to the routing of the cables. Standard lengths of sheeting would be 3m, in this example, and the sheeting is supplied in stacks of such pieces. To comply with the regulations on cable tying, this system comprises a plurality of cable-fixing strips 2 each secured transversely on the sheeting piece, and spaced at regular intervals lengthwise thereof, in this example at intervals of 300mm. In this example, these are strips of Velcro ® hook-and-loop fabric material. Although not shown in the drawings, similar strips of Velcro ® material are provided as bundling strips for the cables, which are wrapped around the cables at 300mm intervals and which are removably attachable to the cable-fixing strips 2 when the cables are laid over the plastics sheeting. In a modification of this example shown in Figure 3, the plastics sheeting comes in the form of box sections 10. Each box section 10 is provided in the form of a flat plastics sheet with preformed elongate lengthwise hinges at the intended corners of the box, to enable it to be folded over as shown in Figure 3 and finally closed using mutually adhesive fixtures 16 and 17. The box section comprises side walls 12 and 13, a base 11 on which the cable-fixing strips 2 are attached, an upper wall 14 and a further flap 15 for attachment over the first side wall 12 using the spaced fixtures 16 and 17. This is floor mountable using the pads 4, as with the example of Figures 1 and 2. The box serves to enclose the cables, and allows further cables to be laid on top. A still further example is shown in Figures 4 and 5. This differs from the examples of Figures 1 , 2 and 3, in that it additionally provides a wire-framed tray or basket 20 for supporting the cables, enabling the entire system to be suspended from a ceiling or attached to a wall, or else to be laid on a floor. Each elongate wire frame tray 20 is typically 50cm to 100cm long and 30cm to 60cm wide. It comprises a pair 21 ,22 of longitudinal wires on one side, and another pair 23,24 of similar longitudinal wires on the other side, joined together by U-shaped cross-wires 25 to which they are welded. Thus each side wall is ladder-shaped, the rungs of the ladder being interconnected by the cross pieces which form the base. As in this example, each rung is continued across the base, but for some applications there could be fewer wires across the base. It is a benefit of the invention that there is no need for any other longitudinal wires, due to the rigidifying effect of the plastics sheeting which is bonded, e.g. by spot welds or adhesive, to the cross-wires 25. Each tray 20 in this example has a number of feet 26, for example consisting of metal clips which project downwards, and which in use support the tray above the floor level. This means of course that the plastics sheet pieces 1 will not need the pads 4. During assembly in use of a cable management system in situ, the required number of trays 20 are joined end-to-end by means of electrically-conductive clips 27, one on each side, although only one is illustrated in Figure 4. These provide continuity of electrical earthing along the tray. Each clip 27 has a generally H- shape, with upper spring clips 28 and lower spring clips 29 gripping respectively the upper 23 and lower 24 wires of the trays 20. The connector 27 is of sheet steel, with rigidifying elongate formations 31 of part cylindrical section projecting from its major surface. A pair of holes 30 are provided in case of a need for earth bonding wires to be bolted through them. Each spring clip 28, 29 is formed with a pair of burr holes acting as earth tangs for penetrating the surface of the respective wires 23,24. Each section of tray 20 is bonded to a corresponding piece of sheeting 1 during manufacture, and is supplied in that form, so that in use each composite component 1 , 20 is connected end-wise to a neighbouring one. In this example, the tray sections 20 are formed using 4mm wires 25 and 5mm wires 21 ,22,23 and 24; the cross-wires 25 are at 50mm spacings. The upper wires 22,23 are welded to the outside of the containment, and the lower wires 21 ,24 are welded to the inside. In a modification of this example shown in Figure 6, vertical partitions 43 and 44 are provided, allowing for different cabling systems to be separated. Thus the top deck can be multi-compartmented, and each compartment can be printed with a different colour for route designation. The cable ties can also be coloured to correspond. The compartment partitions 43,44 may be formed of sheet steel, wire, or plastics sheeting of the type used for the pieces 1. Also shown in Figure 6 is an example of a fixture 41 acting as an edge mounting bracket to a wall or to a support member for suspending from the ceiling. The cable management systems may be adapted to suit bends, T-junctions, cross-overs and other associated shapes. Factory-made kits will also allow for the fitting to be made on site. All fittings or kits will provide for gussets for alleviating stress in the cable when changing direction. Whilst in this example mention is made of data transmission cables, the system is also appropriate for power cables, optical cables and other types of cable. Other types of tray are also envisaged, using wire structures with different configurations, but exploiting the rigidity of the plastics sheeting to which they are connected. Also, different types of plastics sheeting are of course available, and whilst the fluted twin wall type is preferred, other possibilities would include more solid structural plastics sheeting or webbing, for example.

Claims: CLAIMS 1. A cable management system comprising an elongate wire frame tray for supporting cables lengthwise thereof, and flame-retardant plastics sheeting fixed to the base of the tray to form a resiliently deformable lining for cushioning the cables which lining also rigidifies the tray against bending about axes transverse to the length of the tray. 2. A system according to Claim 1 , in which the plastics sheeting has cable fixing members secured at intervals along its length. 3. A system according to Claim 1 or 2, further comprising a plurality of strips for bundling cables together or for encircling a single cable, at intervals along the cable or cables, and for adhering removably to respective ones of the cable-fixing members so as to hold the cable or cables on the sheeting with the cable or cables running generally lengthwise of the sheeting. 4. A system according to Claim 1 , 2 or 3, in which the bundling strips and cable-fixing members are of the Velcro ® type of hook-and-loop fabric. 5. A system according to any of Claims 1 to 4, in which the cable-fixing members are strips spaced at predetermined regular intervals. 6. A system according to any of Claims 1 to 5, in which the sheeting is of twin- wall plastics with lengthwise fluting between the walls. 7. A system according to any of Claims 1 to 6, in which the fluting defines channels of width from 2mm to 8mm. 8. A system according to Claim 6 or 7, in which the twin walls are spaced by 2mm to 6mm. 9. A system according to any of Claims 1 to 8, in which the sheeting has an anti-static surface. 10. A system according to any of Claims 1 to 9, in which the means for fixing the sheeting to the base of the tray comprises spot welds or adhesive. 11. A system according to any of Claims 1 to 10, in which each piece of sheeting further comprises side walls and a top wall which together define an elongate box for enclosing the cable or cables in use. 12. A system according to any of Claims 1 to 11 , in which the box is formed from a single sheeting piece with elongate hinges, and means for fixing the edges together after folding the sheeting over on itself to form a closed box. 13. A system according to Claim 12, in which the means for fixing the edges together comprises self-adhesive pads or Velcro ® type hook-and-loop fabric pads. 14. A system according to any of Claims 1 to 13, in which at least part of the sheeting comprises a metal layer for radio frequency interference shielding the cable. 15. A system according to Claim 14, further comprising transverse partitions for different cables. 16. A system according to any of Claims 1 to 15, in which the partitions are colour coded and/or different portions of the sheeting are colour coded. 17. A system according to any of Claims 1 to 16, comprising a plurality of such elongate wire frame trays, and means for coupling them end-to-end. 18. A system according to Claim 17, in which the coupling means is electrically conductive and grips the wires of both trays to form a good electrical contact for earthing. 19. A system according to any of Claims 1 to 18, in which each tray has ladder- shaped wire side walls interconnected by transverse continuations of at least some of the rungs of the ladders. 20. A system according to any of Claims 1 to 18, in which each tray has a pair of longitudinally-extending wires forming each of two side walls interconnected by cross-wires forming a base. 21. A system according to any of Claims 1 to 20, comprising feet for connection to the underside of the base of the tray, for supporting the tray above floor level in use. 22. A system according to any of Claims 1 to 21 , comprising side connectors for securing a side of the tray to a wall or suspending it from a ceiling. 23. A method of laying cable comprising fitting trays according to any of Claims 1 to 22 end-to-end to form the intended layout for the cable, and laying the cable over the sheeting of the interconnected trays. 24. A method of laying cable comprising fitting trays according to Claim 2, or any of Claims 3 to 22 as dependent upon Claim 2, end-to-end to form the intended layout for the cable, laying the cable over the sheeting and securing it using the cable-fixing members. 25. A method of manufacture of a cable management system comprising fixing flame-retardant plastics sheeting to the base of an elongate wire frame tray for supporting cables lengthwise thereof, to form a resiliently deformable lining for cushioning the cables, which lining also rigidifies the tray against bending about axes transverse to the length of the tray. 26. A method according to Claim 25, comprising spot welding or adhering the said sheeting to the base. 27. A cable management system comprising: pre-formed elongate pieces of flame-retardant sheeting capable of acting as floor decking; means for fixing the sheeting pieces to a floor during installation; and, for each sheeting piece, a plurality of cable-fixing members secured at intervals along its length. 28. A system according to Claim 27, further comprising a plurality of strips for bundling cables together or for encircling a single cable, at intervals along the cable or cables, and for adhering removably to respective ones of the cable-fixing members so as to hold the cable or cables on the sheeting with the cable or cables running generally lengthwise of the sheeting. 29. A system according to Claim 28, in which the bundling strips and cable-fixing members are of the Velcro ® type of hook-and-loop fabric. 30. A system according to any of Claims 27 to 29, in which the cable-fixing members are strips spaced at predetermined regular intervals. 31. A system according to any preceding claim, in which the sheeting is of twin- wall plastics with lengthwise fluting between the walls. 32. A system according to Claim 31 , in which the fluting defines channels of width from 2mm to 8mm. 33. A system according to Claim 31 or 32, in which the twin walls are spaced by 2mm to 6mm. 34. A system according to any of Claims 27 to 33, in which the sheeting has an anti-static surface. 35. A system according to any of Claims 27 to 34, in which the means for fixing the sheeting to a floor comprises self-adhesive pads. 36. A system according to any of Claims 27 to 35, in which each piece of sheeting further comprises side walls and a top wall which together define an elongate box for enclosing the cable or cables in use. 37. A system according to Claim 36, in which the box is formed from a single sheeting piece with elongate hinges, and means for fixing the edges together after folding the sheeting over on itself to form a closed box. 38. A system according to Claim 37, in which the means for fixing the edges together comprises self-adhesive pads or Velcro ® type hook-and-loop fabric pads. 39. A system according to any of Claims 27 to 38, in which at least part of the sheeting comprises a metal layer for radio frequency interference shielding the cable. 40. A system according to any of Claims 27 to 39, further comprising transverse partitions for different cables. 41. A system according to Claim 40, in which the partitions are colour coded and/or different portions of the sheeting are colour coded. 42. A method of laying cable on a floor comprising securing a series of sheeting pieces according to any of Claims 27 to 41 on to the floor along the intended path of the cable, laying the cable over the sheeting and securing it using the cable-fixing strips. 43. A method of laying cable on a floor comprising securing a series of sheeting pieces according to any of Claims 36 to 38 on to the floor along the intended path of the cable, laying the cable over the sheeting and securing it using the cable-fixing strips, and closing the box or boxes over the cable.

Inventors: CONYBEARE ALAN DAVID, CONYBEARE NIGEL PAUL, CONYBEARE, ALAN, DAVID, CONYBEARE, NIGEL, PAUL
Applicants: CABLE BASKET LTD, CONYBEARE ALAN DAVID, CONYBEARE NIGEL PAUL, CABLE BASKET LIMITED, CONYBEARE, ALAN, DAVID, CONYBEARE, NIGEL, PAUL
Application year: 2000
Main classification: H02G3
IPC codes: H02G3