GB2239564A

GB2239564A - Cable trays

Info

Publication number: GB2239564A
Application number: GB9027888A
Authority: GB
Inventors: Kenneth James Gutteridge
Original assignee: GREENINGS Ltd
Current assignee: GREENINGS Ltd
Priority date: 1989-12-22
Filing date: 1990-12-21
Publication date: 1991-07-03
Anticipated expiration: 2010-12-21
Also published as: GB2239564B; GB8929149D0; GB9027888D0

Abstract

A cable tray has a plurality of perforations (10) each perforation having a first dimension greater than a second dimension normal to the first dimension. The perforations are arranged in parallel longitudinal rows (16) and alternately in different orientations in each row. <IMAGE>

Description

Title: Cable Trays DESCRIPTION This invention concerns cable trays.

Cable trays of pressed or folded metal sheet are in common usage. Such trays are perforated along their length to save metal and hence reduce cost and weight and also to provide locations for attachment of support straps and the like to secure the cable tray to a support structure.

In general cable trays are provided with perforations in the form of round holes or elongated slots in uniform arrangement, in which each row of perforations is identical in terms of the shape of perforation and its orientation. It has been found that such arrangements do not provide sufficient flexibility as far as attachment to the tray of support straps and the like. Thus, the positioning of a support strap is more likely to be dictated by the cable tray perforation positions rather than any desired positional attachment of the support strap to a support structure or, indeed, the ease of making such attachment.

An object of this invention is to provide a cable tray having a perforation arrangement that gives greater flexibility as to position of attachment of supporting straps.

According to the invention there is provided a cable tray having a plurality of perforations, each perforation having a first dimension greater than a second dimension normal to the first dimension and said perforations being arranged alternately in different orientations over at least a part of the cable tray.

The preferred perforations have one pair of longer parallel sides connected by shorter arcuate ends.

The perforations are preferably arranged in rows longitudinally of the cable tray and in each row perforations are arranged in alternate orientations.

Preferably some perforations will have their longer first dimension aligned with the longitudinal axis of the cable tray and adjacent perforations in that row with their longer first dimension transverse thereto, preferably normal to the longitudinal axis of the cable tray.

In one preferred embodiment of the invention a cable tray has a plurality of rows of perforations arranged so that each row is offset relative to its adjacent rows. Preferably such offsetting is such that each perforation arranged longitudinally of the cable tray is aligned across the cable tray with transverse perforations of adjacent rows. That arrangement actually provides for transverse rows of alternately orientated perforation as well as longitudinal rows.

In an alternative preferred embodiment offsetting of longitudinal rows of perforations is such that any one perforation is aligned with the spaces between the perforations of adjacent longitudinal rows. That arrangement actually gives transverse rows of like orientated perforations.

This invention will now be further described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows a first cable tray perforation arrangement; and Figure 2 shows a second cable tray perforation.

Referring to Figure 1 of the accompanying drawings, a reverse flange cable tray perforation pattern is shown. The cable tray itself is not illustrated in detail as its formation is well known i.e. having its longitudinal edges turned over to form a channel the sides of which are strengthened by being in effect of double thickness.

The cable tray is perforated for several reasons, including for lightness and to provide locations for attachment of supporting straps or the like. As shown, the perforations 10 have one pair of parallel longer sides 12 and a pair of shorter arcuate ends 14.

The perforations 10 are arranged in rows 16 along the cable tray but each row has its perforations arranged alternately so that perforations 10A have their longer sides 12 parallel with the longitudinal axis of the cable tray and perforations 10B are arranged transversely thereto. Furthermore, each row 16 of perforations is offset relative to its adjacent rows so that rows 18 are formed perpendicular to the rows 16, in which perforations are arranged alternatively as described for rows 16.

Turning now to Figure 2 in which a variation of a perforation arrangement for a cable tray is shown.

Compared to the cable tray of Figure 1, the main difference is that transverse rows of alternate performations are not formed. Rows 16' of alternate perforations 10'A and 10'B are formed but adjacent rows 18' thereof are offset to the extent that transverse rows 18' of like-orientated perforation are formed. The rows 18' themselves have their perforations offset relative to each also.

The main aim of the illustrated cable tray perforations formation is to provide for easier fitting of cable tray supporting straps to the cable trays.

The perforation slot length provides flexibility of fitting locations for a strap to any one perforation and the provision of differently orientated slots provides a greater choice of strap fitting locations an orientations, e.g. so that a cable tray supporting strap may be fitted to a support structure at a more convenient site than might have been available for supporting a cable tray having a less varied perforation arrangement.

Claims

1. A cable tray having a plurality of perforations, each perforation having a first dimension greater than a second dimension normal to the first dimension and said perforations being arranged alternately in different orientations over at least a part of the cable tray.

2. A cable tray as claimed in claim 1, wherein the perforations have one pair of longer parallel sides connected by a shorter arcuate side.

3. A cable tray as claimed in claim 1 or 2, wherein the perforations are arranged in rows longitudinally of the cable tray and in each row perforations are arranged in alternate orientations.

4. A cable tray as claimed in claim 3, wherein some perforations have their longer first dimension aligned with the longitudinal axis of the cable tray and adjacent perforations in that row have their longer first dimension transverse thereto.

5. A cable tray as claimed in claim 4, wherein said adjacent perforations have their longer first dimension normal to the longer first dimension of the other perforations in that row.

6. A cable tray as claimed in any one of claims 1 to 5, having a plurality of rows of perforations arranged so that each row is offset relative to its adjacent rows.

7. A cable tray as claimed in claim 6, wherein said offsetting is such that each perforation arranged longitudinally of the tray is aligned across the tray with transverse perforations of adjacent rows.

8. A cable tray as claimed in claim 6, wherein said offsetting is such that any one perforation is aligned with the spaces between the perforations of adjacent longitudinal rows of like orientated perforations.

9. A cable tray substantially as hereinbefore described with reference to and as illustrated in Figure 1 or Figure 2 of the accompanying drawings.