GB2209632A

GB2209632A - Support trays for pipes or cables

Info

Publication number: GB2209632A
Application number: GB8821702A
Authority: GB
Inventors: Edwin Stuart Gregory; Joseph Goldthorpe Marshall
Original assignee: SWIFTS OF SCARBOROUGH Ltd
Current assignee: SWIFTS OF SCARBOROUGH Ltd
Priority date: 1987-09-05
Filing date: 1988-09-05
Publication date: 1989-05-17
Also published as: GB8821702D0; GB8720945D0

Abstract

The tray 10 has apertures in the base comprising slots 20 extending in the length direction of the tray alternating with slots 22 extending transversely of the tray. Different patterns of slots are disclosed (Figs 2 to 8). <IMAGE>

Description

ImProvements~~Relating~ to~ Cable Trays This invention relates to what are known as cable trays, being elongated channel members having a base and side walls and which serve to contain electrical cables, service pipes and the like in buildings and other enclosures. Such channel members are known as cable trays, and will be referred to hereinafter as such, but it should be borne in mind that the trays need not necessarily hold electrical cables but could additionally or alternatively hold other elongated items such as service pipes.

In order to facilitate the fixing of cables and pipes to the cable tray bases, it is usual to provide apertures in the tray bases through which ties, straps and other fixing devices such as clamps which hold the cables can be passed. Traditionally, the apertures formed in the tray bases have comprised elongated slots which lie with their length directions parallel and at right angles to the length direction of the cable tray.

Whilst this aperture pattern has been satisfactory for the fixing of cables and pipes to the cable tray base using ties and fixing clamps, the aperture pattern has been found to have shortcomings and for example straps which are broader than the normal ties cannot be used for the fixing of the cables to the cable tray base, and this invention has as its object to provide a novel form of aperture pattern for a cable tray.

In accordance with the present invention in its general aspect, cable tray is provided with apertures in the base thereof, said apertures comprising elongate slots some of which lie lengthwise of the cable tray and others of which lie transversely of the length of the cable tray.

Preferably, the slots lying lengthwise of the cable tray, referred to herein as the "in-line" slots alternate lengthwise of the cable tray with the slots, referred to herein as the "transverse" slots, lying in the direction of the length of the cable tray.

In the direction of the length of the cable tray, the slot pattern preferably divides the base into alternating first and second regions, the first regions containing in-line slots, and the second regions containing transverse slots, the said transverse slots in the second regions being located equidistant from the first slots in the first regions on opposite sides of the second regions.

The in-line slots are preferably of the same length and the transverse slots are preferably of the same length but shorter than the in-line slots, and are spaced from the ends of the in-line slots adjacent the transverse slots by an amount less than the length of the in-line slots.

In a particular embodiment, each of said second regions preferably has at one end thereof a circular aperture, the aperture being in alignment in a direction at right angles to the tray length with the transverse slot or slots in such region so that at each edge of the base adjacent the tray wall, and in the direction of the length of the tray, a repeating pattern of in-line slot, transverse slot, in-line slot and circular apertures exists.

In one embodiment as applied to a narrowed form of tray, there are two in-line slots in each first region, and two transverse slots in each second region.

In another embodiment which is of slightly greater width than said narrowed tray, in each first region there are three equally spaced in-line slots, and in each second region there are three transverse slots.

In a still further embodiment and in an even wider form of tray, there are four in-line slots in each first region, and four transverse slots in each second region. In a still further embodiment (a widest form of tray) each first region has six in-line slots, and each second region has six transverse slots.

Also, the transverse apertures in each second region when there are more than one, are in transverse alignment.

The overall width between the centre lines of the outermost in-line slots in each first region is equal to the overall width between the centres of the outermost transverse slots in the second region.

The resulting slot pattern according to the preferred embodiment of the invention enables the utilisation of the conventional ties and clamping devices, but in addition, in providing the in-line slots, wider straps can be used for the strapping of the cables to the tray base.

It is appreciated that other slot pattern configurations can be used without departing from the scope of the invention, but several examples of the preferred embodiment are now described by way of example, with reference to the accompanying diagrammatic drawings, wherein Figures 1, 1A; 2, 2A; 3, 3A and 4, LIA respectively show plan and end elevations of cable trays of four embodiments of the invention according to a first slot pattern; and Figures 5, 6, 7 and 8 show plans of cable trays according to four other embodiments according to another slot pattern.

Referring to the drawings, it should be noted that the drawings are to scale and each of the cable trays shown in the figures is constructed from sheet metal, although other sheet materials may be used, and each comprises a channel member 10 having a base 12 and side walls 1 14, 16. The side walls, are shown as having upwardly facing edges 18, but where the trays are formed to provide more robust support for heavier cables or pipes, the side walls may have inwardly turned top edges, when the trays become what are known as "return flange trays".

The base 12 of each tray is provided with an aperture pattern as clearly illustrated in the drawings, and each pattern comprises elongated in-line apertures 2G, and transverse apertures 22. In the case of Figs. 1 to 4 there are also circular apertures 24. The in-line apertures 20 are all of the same length and width, the transverse apertures 22 are all of the same length and width, although the length of each transverse aperture 22 is slightly less than that of each in-line aperture 22, and, where provided each circular aperture 24 is of a diameter equal to the width of each of the in-line apertures 20 and each of the transverse apertures 22.

The various apertures are arranged in a particular spacial disposition which can be best explained by noting that the apertures divide each base 12 into first and second regions A and B which alternate along the length of the tray. In each region A, are contained in-line apertures 20 (at least two) and these apertures are parallel and spaced by distance dl. In the Figs. 1 and 5 embodiments there are two in-line apertures 20 in each region A, in the Figs. 2 and 6 embodiments there are three in-line apertures 20 in each region A, in the Figs. 3 and 7 embodiments there are four in-line apertures 20 in each region A, and in the Fig. 4 embodiment there are five in-line apertures 20 in each region A, whilst in the Fig. 8 embodiment there are six in-line apertures in region A.In the case of Figures 2, 3 and 4, the in-line apertures are equally spaced by said distance dl.

In the case of Figs. 1 to LI, in each region B, which is of less width than each region A, is contained at least one transverse aperture 22 and at least one circular aperture 224 and of the alternate regions B along the length of the cable tray, the circular aperture alternates between the respective sides of the tray as shown. In the case of Fig. 1, each region B has a single transverse slot 22, in the case of the embodiment of Fig. 2 each region B has two transverse slots 22, in the case of the embodiment of Fig. 3, each region B has three transverse slots 22, and in the case of the embodiment of Fig. 4, each region B has four transverse slots 22. It can be seen therefore that if region A has N in-line slots, then region B on the same cable tray has (N - 1) transverse slots 22, and these transverse slots are in transverse alignment with each other and also with the circular aperture 24.

The spacial disposition of the respective in-line and transverse slots 20, 22 and circular apertures 24 is important in the preferred embodiment and in particular, the overall width W1 between the outer edges of the outer slots in the sections A is equal to the overall width W2 of each section B from the outer edge of the circular aperture, to the end of the outermost transverse slot 22.

In the Figs. 1 to 4 embodiments, the trays illustrated in the figures have nominal widths (outside sizes) as follows: Fig. 1 50 mm Fig. 2 75 mm Fig. 3 100 mm Fig. 4 150 mm The length of each in-line slot is 20.7 mm, the length of each transverse slot is 15 mm and the width of each in-line slot, each transverse slot and the diameter of each circular aperture is 7 mm.

The transverse pitching dl between in-line apertures in the Figs. 1 to 4 embodiments in each section h is 18 mm, the spacing d2 between the ends of the transverse slots and the circular aperture in each section B is 10 mm, and the pitching between the centre lines of sections A and B is 25 mm, making the pitching between sections A, or the pitching between sections B, 50 mm.

In the embodiments of the inventions in Figs. 6 to 8, the circular aperture 24 is omitted, and the transverse apertures 22 are symmetrically arranged as are the inline apertures 20 relative to a centre line CL of the cable tray. In each case, in a direction longitudinally of the tray, an in-line aperture alternates with a transverse aperture, and the centres of the alternating in-line and transverse apertures are in alignment.

The cable trays of Figs. 5, 6, 7 and 8 may be generally of the same width as the trays of Figs. 1 to LI, and the dimensions of the transverse and in-line apertures may be the same as those in Figs. 1 to 4.

The particular disposition and sizing of the various slots and apertures provides not only the flexibility for the fastening of the cables in the various fashions indicated herein, and which flexibility is greater than the flexibility of the heretofore known cable trays, but in addition the layouts have been selected in order to provide the trays with an aesthetically pleasing appearance.

Claims

1. A cable tray provided with apertures in the base thereof, said apertures comprising elongate slots some of which lie lengthwise of the cable tray and others of which lie transversely of the length of the cable tray.

2. A cable tray according to Claim 1, wherein the slots lying lengthwise of the cable tray, referred to herein as the "in-line" slots alternate lengthwise of the cable tray with the slots, referred to herein as the "transverse" slots, lying in the direction of the length of the cable tray.

3. A cable tray according to Claim 2, wherein, in the direction of the length of the cable tray, the slot pattern divides the base into alternating first and second regions, the first regions containing in-line slots, and the second regions containing transverse slots, the said transverse slots in the second regions being located equidistant from the first slots in the first regions on opposite sides of the second regions.

4. A cable tray according to Claim 3, wherein the inline slots are of the same length and the transverse slots are preferably of the same length but shorter than the in-line slots, and are spaced from the ends of the in-line slots adjacent the transverse slots by an amount less than the length of the in-line slots.

5. A cable tray according to Claim 3 or LI, wherein each of said second regions has at one end thereof a circular aperture, the aperture being in alignment in a direction at right angles to the tray length with the transverse slot or slots in such region so that at each edge of the base adjacent the tray wall, and in the direction of the length of the tray, a repeating pattern of in-line slot, transverse slot, in-line slot and circular apertures exists.

6. A cable tray according to Claim 3 or 4, wherein there are two in-line slots in each first region, and two transverse slots in each second region.

7. A cable tray according to Claim 3 or LI, wherein in each first region there are three equally spaced inline slots, and in each second region there are three transverse slots.

8. A cable tray according to Claim 3 or 4, wherein there are four in-line slots in each first region, and four transverse slots in each second region.

9. A cable tray according to Claim 3 or 4, wherein each first region has six in-line slots, and each second region has six transverse slots.

10. A cable tray according to any of Claims 2 to 9, wherein the transverse apertures in each second region when there are more than one, are in transverse alignment.

11. A cable tray according to any of Claims 2 to 10, wherein the overall width between the centre lines of the outermost in-line slots in each first region is equal to the overall width between the centres of the outermost transverse slots in the second region.

12. A cable tray substantially as any of the embodiments hereinbefore described with reference to the accompanying drawings.