GB2590050A

GB2590050A - Cable clip and cable assembly

Info

Publication number: GB2590050A
Application number: GB1911814.0A
Authority: GB
Inventors: Lee Duffy Simon
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-08-16
Filing date: 2019-08-16
Publication date: 2021-06-23
Anticipated expiration: 2039-08-16
Also published as: GB2590050B; GB201911814D0

Abstract

A clip 2 for electrical cables is formed from a piece of wire, and comprises a central portion 4, extending generally horizontally in use, and first and second hooks 6 provided at ends of the central portion. Each hook comprises an outer part 8 that extends generally vertically in use, a curved apex 12, and a re-entrant part 10 extending at an acute angle to the outer part 8. In one method of attaching the clip 2 to a cable tray 20 having an upper horizontal plate 22 and two rails 24 depending from the plate one on either side, the clip is placed across the tray and each of the hooks 6 is inserted into a hole 26 in a respective one of the rails 24, the holes facing each other.

Description

CABLE CLIP AND CABLE ASSEMBLY Background to the Invention [0001] This invention relates to a cable clip and to a cable assembly.

[0002] Electrical cables are often located in overhead locations in buildings. In the past, in the event of fires, heat or flames caused cables to fall from ceiling voids. In some cases firefighters became entangled with the cables and were killed.

[0003] As a result, regulations (BS 7671 in the United Kingdom) require the retaining means for cables to be heat resistant. Cables are typically located in inverted metallic trays, which are elongate structures having an upper horizontal plate and two rails depending from the plate, one on either side, arranged vertically. These are attached to a structural ceiling above a dropped ceiling. The plate and the rails are formed with an array of holes. The cables are tied to the tray by means of cable ties, generally comprising flexible strips of stainless steel, threaded through the holes. These may be of the ball-lock type in which an angled tail of the tie is inserted into a head containing a steel ball that locks the tie. The ties are spaced apart from each other at intervals of no greater than 900 mm.

[0004] Installing cables using such ties is intricate and laborious. Thus, often gloves cannot be worn, which makes the work particularly time consuming in cold conditions.

Summary of the Invention

[0005] It is an aim of the invention to provide a clip that is easier to install and remove than the known cable ties.

[0006] The present invention provides a clip for electrical cables formed from a piece of wire, the clip comprising a central portion, extending generally horizontally in use, and first and second hooks provided at ends of the central portion, each hook comprising: an outer part that extends generally vertically in use, a curved apex, and a re-entrant part extending at an acute angle to the outer part.

[0007] The shape of the central portion may be outwardly convex. The length of the central portion is slightly greater than the width of a cable tray. In one method of attaching the clip to a tray, it is placed across the tray and each of the hooks is inserted into a hole in a respective one of the rails, the holes facing each other. This is easily done by simply aligning the clip with the holes and pushing it upwards until the re entrant parts enter the holes. Alternatively one can insert one of the hooks into a first such hole, and pivot the clip upwards until the other hook enters the hole in the other rail.

[0008] The clip can easily be removed by pushing it upwards. The apices of the hooks contact the upper edges of their respective holes and the re-entrant parts are caused to exit the holes.

[0009] A second method of attaching the clip to a fray comprises inserting either or both of the hooks into holes in the upper plate of the tray. When both hooks are being so inserted, the distance between the holes is less than the distance between the ends of the hooks in an unstressed state of the clip. One or both of the hooks is deformed outwardly on insertion of the clip as the inwardly facing surface of the end of the hook(s) bears against the inner end of the hole(s). The clip can then be removed by pulling one of the hooks outwardly, until its end is above the hole, and then downwardly through the hole, until the other hook can also be removed.

[0010] The clip may be formed from a high-temperature alloy and may be galvanised.

[0011] The invention also provides a cable assembly comprising a cable tray formed with a plurality of holes and comprising an elongate upper plate, and first and second rails depending vertically from said plate, the cable tray containing one or more cables, and at least one clip as described above, having the first hook lodged in a first hole in the cable tray and the second hook lodged in a second hole in the cable tray, so as to retain the one or more cables in the cable tray. The first and second holes may be located in the first and second rails respectively and may face each other. Alternatively the first and second holes may be located in the upper plate.

[0012] The cable tray may be made from steel, which may be galvanised. If one of the cable tray and the clip is not galvanised, but the other is galvanised, the non-galvanised part may be coated, e.g. with polyester, to inhibit galvanic corrosion.

Brief Description of the Drawings

[0013] The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings, in which; [0014] Figure 1 shows a clip according to the invention; [0015] Figure 2 is an end view of a cable tray with the clip of Figure 1 attached thereto; and [0016] Figure 3 is a perspective view of the cable tray and attached clip of Figure 2.

Detailed Description of Particular Embodiments

[0017] Figure 1 shows a cable clip 2 formed from a piece of wire. It comprises a central portion 4 which is bowed slightly outwardly, and two hooks 6, one at each end of the clip. Each hook 6 comprises a main part 8 and a re-entrant part 10. The main parts 8, extending substantially at a right angle to the central portion 4 and are mutually parallel in the unstressed state of the clip. The transition from the main part 8 to the re-entrant part 10 is formed as a curved apex 12. The re-entrant parts 10 extend towards the central portion 4 at acute angles to the respective main parts 8.

[0018] The end faces 12 of the clip are cut at an acute angle to the uppermost, inward facing generatrix 14, for ease of insertion and removal of the hooks 6.

[0019] The dip 10 is formed from a wire of high-temperature alloy. A suitable material is mild steel having a melting point of at least 1450 °C. This may be galvanised with a coating of zinc or zinc iron alloy, optionally including a small amount (e.g. less than 0.2 % by weight) of lead or antimony. In addition, the galvanised wire may he coated with oil, phosphate or chromate.

[0020] Figures 2 and 3 show the clip 2 in place on a cable tray 20. The cable tray comprises an upper horizontal plate 22, which can be fixed to a ceiling, and rails 24 depending downwardly at the sides of the plate 22. The rails 24 include holes 26.

[0021] To attach the clip 2 to the tray 20, the clip can simply be aligned with the holes 26, across the tray, and pushed upwards until the re-entrant parts enter the holes. Alternatively one of the hooks can be inserted into a first such hole 26 in one of the rails 24. The dip is then pivoted upwards until the other hook 6 enters a hole 26 in the other rail.

[0022] Where a cable tray is wider than the clip, it also possible to engage one of the hooks 6 in a hole in the upper plate of that tray, and the other hook 6 in a hole 26 in one of the rails, or to engage both hooks in holes in the upper plate.

[0023] In its installed position the clip 2 is secure in place in the tray 20 and can retain electrical cables within the tray. Clips are spaced along the tray at suitable intervals.

[0024] For removal from the tray 20, the clip 2 is pushed upwards. The apices 12 of the hooks 6 contact the upper edges of their respective holes 26 and the reentrant parts are caused to exit the holes.

[0025] The invention thus provides a fire-resistant clip that can be installed and removed easily, even by a person wearing gloves.

Claims

CLAIMS1. A clip for electrical cables, the clip being formed from a piece of wire, and comprising a central portion, extending generally horizontally in use, and first and second hooks provided at ends of the central portion, each hook comprising: an outer part that extends generally vertically in use, a curved apex, and a reentrant part extending at an acute angle to the outer part.
2. A clip according to claim 1, wherein the shape of the central portion is outwardly convex.
3. A clip may according to claim 1 or 2, formed from a high-temperature alloy.
4. A clip according to claim 1, 2 or 3, wherein the clip is galvanised.
5. A method of attaching the clip according to any preceding claim to a cable tray having an upper horizontal plate and two rails depending from the plate one on either side, wherein the length of the central portion of the clip is slightly greater than the width of the cable tray, and the clip is placed across the tray and each of the hooks is inserted into a hole in a respective one of the rails, the holes facing each other.
6. A method according to claim 5, wherein the clip is aligned with the holes and pushed upwards until the re-entrant parts enter the holes.
7. A method according to claim 5, wherein one of the hooks is inserted into a first one of the holes in one of Lhe rails, and Lhe clip is pivoted upwards until the other hook enters the hole in the other rail.
8. A method of attaching the clip according to any one of claims 1 to 4 to a cable tray having an upper horizontal plate and two rails depending from the plate one on either side, the method comprising inserting one or both of the hooks into one or two of the respective holes in the upper plate of the tray.
9. A method according to claim 8, wherein both hooks are inserted into respective holes, and during such insertion, the distance between the holes is less than the distance between the ends of the hooks in an unstressed state of the clip.
10. A cable assembly comprising a cable tray formed with a plurality of holes and comprising an elongate upper plate, and first and second rails depending vertically from said plate, the cable tray containing one or more cables, and at least one clip according to any one of claims 1 to 4, having the first hook lodged in a first hole in the cable fray and the second hook lodged in a second hole in the cable tray, so as to retain the one or more cables in the cable tray.
11. A cable assembly according to claim 10, wherein the first and second holes are located in the first and second rails respectively and may face each other.
12. A cable assembly according to claim 10, wherein the first and second holes are located in the upper plate.
13. A cable assembly according to claim 10, 11 or 12, wherein the cable tray is of galvanised steel.
14. A cable assembly according to any one of claims 10 to 13, wherein one of the cable tray and the clip is not galvanised, and the other of the cable tray and the clip is galvanised, the non-galvanised one of the cable tray and the clip being coated to inhibit galvanic corrosion.