GB2423647A

GB2423647A - Connecting cable trunking

Info

Publication number: GB2423647A
Application number: GB0502674A
Authority: GB
Inventors: David Ravenhill; Hezar Qasim
Original assignee: Legrand Electric Ltd
Current assignee: Legrand Electric Ltd
Priority date: 2005-02-09
Filing date: 2005-02-09
Publication date: 2006-08-30
Anticipated expiration: 2025-02-09
Also published as: GB2423647B; GB0502674D0

Abstract

A method of fastening assembled sections of cable trunking (30,31, Fig 1), the method including passing the distal end (14) of a fastening component through through-holes (32,34, Fig 1) in proximal and distal walls of respective sections of cable trunking (30,31, Fig 1), and turning the fastening component about its axis to a turned position, wherein the distal end (14) of the fastening component is configured such that in said turned position the fastening component is prevented from being withdrawn back through said through-hole (32, Fig 1) in said distal wall by interaction of said distal end of the fastening component with the distal surface of said distal wall.

Description

CABLE TRUNKING AND DUCTING

The present invention relates to housing structures for routing cabling, and particularly to interconnectable sections of cable trunking and ducting.

Conventional cable trunking and ducting is comprised of sections that are insertable into each other, and after insertion the sections are secured together by screws, generally from the sides via an open face of the sections used to later insert the cabling before closing with a lid.

The present invention has the aim of providing an alternative technique for fastening such sections together.

According to one aspect of the present invention, there is provided a method of fastening assembled sections of cable trunking or ducting, the method including passing the distal end of a fastening component through through- holes in proximal and distal walls of respective sections of cable trunking or ducting, and turning the fastening component about its axis to a turned position, wherein the distal end of the fastening component is configured such that in said turned position the fastening component is prevented from being withdrawn back through said through-hole in said distal wall by interaction of said distal end of the fastening component with the distal surface of said distal wall.

I

According to another aspect of the present invention, there is provided a method of routing cabling, comprising the steps of assembling sections of cable trunking or ducting; fastening the assembled sections by the abovementioned method; and housing cabling in the assembled sections.

According to another aspect of the present invention, there is provided a combination of a pair of sections of cable trunking or ducting and a fastening component, wherein the fastening component has a distal end configured to pass through through-holes in proximal and distal walls of said pair of sections of cable trunking or ducting, but also configured such that upon turning thereof about its axis to a turned position it is then prevented from being withdrawn back through said through-hole in said distal wall by interaction of said distal end with the distal surface of said distal wall.

In one embodiment, the fastening component is configured such that said turning thereof gradually increases the force of contact between said distal end thereof and said distal surface of said distal wall.

In one embodiment, the distal end of said fastening component is provided with serrations configured to scratch said distal surface of said distal wall upon said turning thereof.

In one embodiment, the proximal end of the fastening component is also provided with serrations configured to scratch the proximal surface of said proximal wall upon turning thereof.

An embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:Figure 1 shows two interconnectable sections of cable trunking adapted for use in a method according to an embodiment of the present invention; Figure 2 is a comparative view of the through-holes of the sections of Figure 1; Figure 3 is a plurality of views of a fastener for securing the two sections of Figure 1 together according to an embodiment of the present invention; and Figure 4 shows the interaction of the fastener of Figure 3 with the walls of the sections of Figure 1.

A first longitudinal section of cable trunking 30 of relatively small width (Coupler) is slidably insertable into a second longitudinal section of cable trunking 31 (Trunk) of relatively large width. The first section 30 is provided with at least one substantially rectangular through-hole 32. The second section 31 is provided with substantially circular through- holes 34 at corresponding location(s) thereof. The relative size and shape of the triangular and circular through-holes is shown in Figure 2. The narrow first section 30 is slidably inserted into the wide second section 31 such that corresponding rectangular and circular through-holes 32, 34 line up with each other. The two sections are then secured together using the fastener shown in Figure 3, as discussed below.

The fastener is a solid metal casting including a head portion 2, a neck portion 12, and a base portion 14. The diameter of the head portion 2 is selected such that it cannot pass through either the rectangular or circular through- holes 32, 24. The shape and dimensions of the base portion 14 are selected such that it can pass through the circular through-hole 34, and such that it can pass through the rectangular through-hole 32 when in one orientation but not when turned about its axis from such orientation to a different orientation.

The neck portion 12 includes a sub-portion 4 of relatively large diameter adjacent the head portion 2. The diameter of this sub-portion 4 is selected such that it fits closely into the circular through-hole 34 for rotation of the fastener about its axis therein, but cannot pass through the rectangular through-hole 32.

The fastener is inserted into the through-holes 32, 34 from the side of the wide second section 31 in an orientation such that the base portion passes through both the circular and rectangular through-holes 32, 34. The wide neck sub-portion 4 then sits in the circular through-hole 34, as mentioned above.

The head portion 2 of the fastener is configured 24 to receive the tip of a screwdriver and the fastener is turned about its axis using a screwdriver to an orientation in which the base portion 14 of the fastener is unable to pass back through the rectangular through-hole 32 thereby locking the two trunking sections together.

The inner surface 18 of the base portion 14 (i.e. the surface of the base portion 14 facing towards the wall of the narrow section 30 when the base portion is passed right through the rectangular throughhole 32) is configured such that turning the fastener about its axis acts to force the walls of the two trunking sections 30, 31 towards each other. The resulting increased contact forces act to better prevent the fastener from later turning back in the opposite direction of rotation. This is achieved by providing the inner surface of the base portion 12 with two spirally sloped portions each extending through about 180 degrees, which simultaneously act to increase the contact forces between the fastener and the walls of the trunking sections 30, 31 when the fastener is turned about its axis.

Both the spirally sloped inner surface of the base portion and the undersurface of the head portion are provided with serrations 8, 10, 20, which are designed to scratch the surface of the walls of the respective trunking sections. As well as serving to further increase the contact forces between the fastener and the walls of the trunking sections, they can also act to cut through any relatively soft surface layer (such as a paint layer) on the walls of the trunking sections down to the underlying metal and thus improve the electrical connection between the two sections. This can be particularly important where the series of trunking sections are intended to provide an electrical pathway to earth.

The serrations are shaped such that they present a relatively gently sloped face to the section walls when turned in the locking direction but present a relatively steeply sloped face (substantially perpendicular face) to the section walls when turned in the opposite direction. The thus-shaped serrations have the effect of further preventing the fastener from accidentally turning back about its axis and becoming loose.

Figure 4 shows the fastener in a locked orientation with the walls of the trunking sections 30, 31 forcibly sandwiched between the undersurface of the head portion 2 and the spirally sloped surface 18 of the base portion.

In the case of overhead cable trunking and ducting, the sections might be mounted such that the base walls are at the top so that cabling can be inserted into the sections from below. After inserting the cabling into the trunking, a lid (not shown) would then normally be fitted to the underside of the trunking to hide the cabling. In such a case, it might be more convenient to provide the circular through-holes 34 on the narrow trunking section 30 and the rectangular through-holes on the wide trunking section 31 such that the fastener can be inserted from the side of the narrow trunking section 30.

The fastener may, for example, be a zinc or other metal casting produced by die casting or investment casting.

As mentioned above, the embodiment shown in the Figures and described in detail above is only one example of how the invention could be carried out, and is not intended to be limiting in any way.

The applicant draws attention to the fact that the present invention may include any feature or combination of features disclosed herein either implicitly or explicitly or any generalisation thereof, without limitation to the scope of any definitions set out above. In view of the foregoing description it will be evident to a person skilled in the art that various modifications may be made within the scope of the invention.

Claims

1. A method of fastening assembled sections of cable trunking or ducting, the method including passing the distal end of a fastening component through through-holes in proximal and distal walls of respective sections of cable trunking or ducting, and turning the fastening component about its axis to a turned position, wherein the distal end of the fastening component is configured such that in said turned position the fastening component is prevented from being withdrawn back through said throughhole in said distal wall by interaction of said distal end of the fastening component with the distal surface of said distal wall.

2. A method according to claim 1, wherein said fastening component is configured such that said turning thereof gradually increases the force of contact between said distal end thereof and said distal surface of said distal wall.

3. A method according to claim I or claim 2, wherein said distal end of said fastening component is provided with serrations configured to scratch said distal surface of said distal wall upon said turning thereof.

4. A method according to any preceding claim, wherein the proximal end of the fastening component is also provided with serrations configured to scratch the proximal surface of said proximal wall upon turning thereof.

5. A combination of a pair of sections of cable trunking or ducting and a fastening component, wherein the fastening component has a distal end configured to pass through through-holes in proximal and distal walls of said pair of sections of cable trunking or ducting, but also configured such that upon turning thereof about its axis to a turned position it is then prevented from being withdrawn back through said through-hole in said distal wall by interaction of said distal end with the distal surface of said distal wall.

6. A combination according to claim 5, wherein said fastening component is configured such that said turning thereof gradually increases the force of contact between said distal end thereof and said distal surface of said distal wall.

7. A combination according to claim 5 or claim 6, wherein said distal end of said fastening component is provided with serrations configured to scratch said distal surface of said distal wall upon said turning thereof.

8. A combination according to any of claims 5 to 7, wherein the proximal end of said fastening component is also provided with serrations configured to scratch the proximal surface of said proximal wall upon turning thereof.

9. A method of routing cabling, comprising the steps of assembling sections of cable trunking or ducting; fastening the assembled sections by a method according to any of claims 1 to 4; and housing cabling in the assembled sections.

10. A fastening component for use in the method of claim 1, wherein the fastening component is provided with serrations configured to scratch the surface of the walls of the sections.