GB2290091A - Channel member for ducting - Google Patents

Abstract

A channel member adapted for using in forming a duct in a floor is formed from a rigid material and comprises: (i) a base (33), (ii) walls upstanding from the base along two opposite sides of the base, being adapted to form a channel; (iii) each wall having a flange (34) directed inwardly with respect to the channel at a short distance from the uppermost-in-use edge (32) of the wall, each flange extending over a minor part of the width of the base; characterised in that at least one of the channel member walls incorporates an undercut groove (36), said groove being adapted to accept a securing key or securing strip which enables the channel member to be anchored to the surrounding structure, e.g. concrete. <IMAGE>

Description

DUCTING Field of the Invention This invention relates to a channel member for use in forming a duct in a floor, to a floor including such ducting, and to a method of forming ducting in a floor.

Background to the Invention In locating, for example, central heating pipe work in buildings having solid floors, it has been a common practice simply to embed the pipes, possibly within a sheath of insulation, within the concrete of the floor. This arrangement gives rise to problems if a leaking pipe is to be repaired after installation, or the layout of the installation is to be changed. It is desirable, therefore to locate pipe work in ducting to which access may more readily be gained for subsequent work on the pipes, and in the United Kingdom such an arrangement is now provided for by regulations. Similar principles are applied to the installation of cables within solid floors.

For convenience in forming such ducting, plastics channel members may be embedded in the concrete during formation of the floor, the channel members being provided with outwardly extending flanges which are supported by the underlying concrete and which in turn serve for location of a closure member for the channel. A problem which arises with such ducting is that, when forming the pipe work, it is common practice to provide soldered joints and the heat of the blow lamp used in the soldering operation can damage the plastic channel unless special care is taken.

Furthermore, the plastics channel is prone to mechanical damage during subsequent building operations before the floor is completed.

In order to provide better thermal insulation, another type of floor is becoming more common. This provides on top of the concrete slab a layer of substantially rigid insulating material such as an expanded plastics material, with boards, typically plywood, chipboard or the like, resting on top of the insulating material. This type of floor is known as a "floating floor". For this type of flooring, the conventional plastics ducting channel member is inappropriate, since its tapering form flanges and low mechanical strength make satisfactory insulation difficult.

To overcome these disadvantages a new type of ducting has been developed and this is described in international patent specification WO/93 08348 and is illustrated in figures 1-3.

This novel type of ducting is conveniently formed from a sheet of galvanised steel bent to form two walls 2 upstanding at right angles from a base 3. Each wall has a longitudinal flange 4 extending inwardly therefrom. The distance from the upper face of the flange 4 and the underside of the base 3 corresponds to the thickness of the insulation used in the floating floor.

Furthermore, the distance from the upper face of the flange 4 to the top of the wall 2 corresponds to the thickness of the wood used in the floor surface.

Alternatively, this type of duct can be extruded from a metal such as aluminium.

This arrangement has generally proved adequate for installation in floating floors but suffers from a number of drawbacks. Firstly, this type of duct cannot be used successfully when buried in a conventional screed/concrete floor because there are no external anchorages to key the duct into the floor.

Secondly, there is no provision to join the lengths of duct together when longer duct runs are required.

Thirdly, there is no provision to join ducts together side by side where the volume of pipes, cables or the like is too great to be accommodated in one duct alone.

Ducts specifically designed to be set into concrete floors are known and are described, for example, in Swiss Patent No 529 897, US Patent No 3,593,472 and Dutch Patent No 6,600,598. However, these types of ducts are totally unsuitable for installation into floating floors because of their fixed external flange arrangements.

During building work it is often necessary to install duct work in both floating and conventional screed floors. Currently a contractor is require to carry stocks of different types of duct work if the work is to be carried out to the correct specification. Furthermore, not only will different types of ducts be required but different sizes will also need to be held in stock depending upon the number or size and type of pipes and cables that have to be installed.

It is the object of this invention to provide a channel member for forming a duct which can be used equally effectively in all types of floor including raised "computer room" floors.

Summarv of the Invention One embodiment of the present invention provides a channel member adapted for use in forming a duct in a floor, that channel member being formed from a rigid material and comprising: (i) a base; (ii) walls upstanding from the base along two opposite sides of the base, being adapted to form a channel; (iii) each wall having a flange directed inwardly with respect to the channel at a short distance from the uppermost-in-use edge of the wall, each flange extending over a minor part of the width of the base; characterised in that at least one of the channel member walls incorporates an undercut groove, said groove being adapted to accept a securing key or securing strip which enables the channel member to be anchored to the surrounding structure.

Preferably the groove is recessed into the wall of the channel member such that no part of the groove extends beyond the outer surface of the channel member wall.

Preferably each wall of the channel member incorporates such an undercut groove.

Preferably the securing key or strip has a cross-sectional profile comprising an elongate body portion and a head at one end of the body, the head being adapted to slidingly engage the key in the groove.

In a particular preferred embodiment the body portion of the securing key is L-shaped or T-shaped in cross-sectional profile.

In a further embodiment the securing key or strip has a cross-sectional profile comprising an elongate body portion and a head at each end of the body, the heads being adapted to slidingly engage the key in the grooves of adjacent channel members thus enabling two or more channels to be linked side by side in substantially parallel non-coaxial corresponding end alignment.

Brief Description of the Drawings A preferred embodiment of the present invention will now be more particularly described by way of example only, with reference to the accompanying drawings, wherein: Figure 1 is a perspective view of a portion of a prior art channel member; Figures 2 and 3 are perspective views of a portions of floor partially sectioned showing stages in the installation of the prior art channel member of the type shown in Figure 1 to form a pipe work duct in the floor; Figure 4 shows a cross-section of a channel member of one embodiment of the present invention; Figure 5 shows a enlarged cross-section of the undercut groove shown in Figure 4; Figure 6 shows a cross-section of a differently dimensioned duct; Figure 7 shows a cross-section of a securing key according to the invention with an L-shaped body portion;; Figure 8 shows a cross-section of a double-headed securing key suitable for connecting two channel members together side by side.

Description of the Preferred Embodiment A presently preferred embodiment will now be described by way of example only. Referring to Figure 4, the channel member 31 is conveniently formed by extrusion using a metal such as aluminium. The height of walls 32 from the base 33 is conveniently chosen to be just less than the sum of the thickness of insulation material and the surface layer boarding in a floating floor. However, deeper or shallower channel members can be constructed where they are intended principally to be set into a concrete floor.

The distance between the upper face of the flange 34 and the underside of the base 33 corresponds to the thickness of the insulation used in the floor.

Furthermore, the distance from the upper face of the flange 34 to the top of the wall 32 corresponds to the thickness of wood used in the floor surface.

The use of aluminium or steel in the fabrication of the channel member means that the member will be undamaged by the application of a blow torch during pipe soldering operations, while providing sufficient strength to support that portion of the floor overlying the channel. In addition, the metal may be readily cut to permit the formation of junctions or elbows in the ducting layout.

An undercut groove 36 is formed in the side walls 32, the groove preferably being formed as part of the extrusion process. The groove is designed to retain the head of a securing key 37 which can take the form of either short lengths of rigid material or a strip which potentially extends for the entire length of the channel member.

It will be appreciated that for the channel member still to fit within a channel cut into a floating floor the walls 32 of channel member 31 must contain no protuberances i.e. the groove must be recessed into the channel member and should not extend beyond the outer surface of the otherwise substantially planar wall.

The exact shape and confirmation of the groove can vary widely so long as it can retain the key 37 and it need not be located at any particular point on the wall 32.

It will also be appreciated that this securing key can have a number of important functions. Firstly, it can be used to key the channel member into the surrounding floor. To this end the key 37 is preferably L-shaped, as shown in Figure 7, or even T-shaped (not shown). In one method of operation the key 37 takes the form of short lengths of a rigid material such as aluminium or steel which are sequentially inserted into the groove 36 from one or both ends of the channel member and spaced periodically along the length of the channel member to form a series of anchoring points. In the case of L-shaped keys, alternate keys can be inverted to maximise their retaining capability.

Alternatively the key 37 can take the form of a long strip having the crosssectional profile shown in Figure 7.

Secondly, by using a double-headed securing key 38, as shown in Figure 8, two or more channel members can be joined side by side to expand the duct capacity. Alternatively, this can enable different pipes and/or cables to be carried in a segregated fashion within the same duct system.

Thirdly, either type of securing key can be used to link lengths of duct together in an end to end fashion to provide a continuous duct of any desired length. If it is necessary to fix these lengths in their joined-up state this can easily be achieved by drilling through the wall of the groove and securing the key to the groove using a short self-tapping screw or the like. In the case of a channel member to be used in a floating floor the joining key can have the form of the key head only i.e. no part of the key need extend beyond the groove and thus the channel wall retains a substantially smooth and planar appearance.

Fourthly, if two securing keys 37 are formed or joined at an angle (not shown) then two channel members can be joined at that angle. As an example, two channel members can be formed at right angles using this technique.

The securing key can take the form of a strip extruded in the same lengths as the channel members. The strip can therefore extend for the entire length of the duct or can be cut to any suitable length on site.

A lid to the channel member can be provided as a separate extrusion (not shown) or alternatively the section of board removed from the channel cut in a floating floor can provide the lid.

Channel members as described above can be used for ducting cables as well as pipes. In this case it may be convenient to include cable trays, tidies, clips or the like and such items will be known per se to the intended skilled addressee of this specification so require no further definition here.

Provision for earthing the channel members can also be provided (not shown).

These channel member(s) can also be incorporated into a raised floor as would be found these days in modern office buildings or in computer rooms.

In this case, the raised floor tiles can act as a lid to the channel member, obviating the need for a separate lid.

When used for cable ducting it may be necessary for the channel member to carry fibre optic cables. In this case bends of sufficiently gentle radius are required such that the cable will not be damaged when it is placed in the channel member. To facilitate this, special bent sections of channel member 31 can be provided (again not shown) and they can be joined to the main duct runs as described above.

The reader is directed to the disclosure in patent specification No PCT/GB92/01921 for any further details he may need for putting the invention into practice.

Claims (7)

Claims

1. A channel member adapted for using in forming a duct in a floor, the channel member being formed from a rigid material and comprising: (i) abase; (ii) walls upstanding from the base along two opposite sides of the base, being adapted to form a channel; (iii) each wall having a flange directed inwardly with respect to the channel at a short distance from the uppermost-in-use edge of the wall, each flange extending over a minor part of the width of the base; characterised in that at least one of the channel member walls incorporates an undercut groove, said groove being adapted to accept a securing key or securing strip which enables the channel member to be anchored to the surrounding structure.

2. A channel member as claimed in Claim 1 wherein the groove is recessed into the wall of the channel member such that no part of the groove extends beyond the outer surface of the channel member wall.

3. A channel member as claimed in Claim 1 or Claim 2 wherein each wall of the channel member incorporates an undercut groove.

4. A channel member as claimed in any preceding Claim wherein the securing key or strip has a cross-sectional profile comprising an elongate body portion and a head at one end of the body, the head being adapted to slidingly engage the key in the groove.

5. A channel member as claimed in Claim 4 wherein the body portion of the securing key is L-shaped or T-shaped in cross-sectional profile.

6. A channel member as claimed in any of Claims 14 wherein the securing key has a cross-sectional profile comprising an elongate body portion with a head at each end of the body, the heads being adapted to slidingly engage the key in the grooves of adjacent channel members thus linking two channel members side by side in substantially parallel non-coaxial corresponding end alignment.

7. A channel member substantially as herein described with reference to and as illustrated in any combination of Figures 4-8.