GB2367433A

GB2367433A - Earth connector for pipes

Info

Publication number: GB2367433A
Application number: GB0023600A
Authority: GB
Inventors: Clive Dickson Robinson
Original assignee: Individual
Current assignee: Individual
Priority date: 2000-09-27
Filing date: 2000-09-27
Publication date: 2002-04-03
Also published as: GB0023600D0

Abstract

An earth connector for pipes comprises a body 101, 102 which receives an earth electrical connection and an adjustable strap 112 which adjustably fastens the body in electrical connection with a pipe. The body includes fixing teeth 106 which prevent movement to the body relative to the pipe. The two body parts 101, 102 are interconnected by an adjustable fastener 114 which can constrain an earthed conductor 113 between the two parts 101, 102. Spread resistance means comprising a pair of wing members 104 are urged towards the pipe by strap 112.

Description

IMPROVED EARTH CONNECTOR FOR PIPES This invention relates to an improved earth connector for pipes.

Conventionally, if an earth connection is required to be made to pipes, the connection is made using a so-called pipe clip which comprises a body which is connected to the pipe by way of an adjustable strap which passes around the pipe and through the body and when adjusted so as to secure the body relative to the pipe by a fastener, secures the body in eiectricai contact with the pipe. The body includes an electric terminal to which an earth connection can be made thereby connecting the body and hence the pipe to earth.

Problems exist with conventional pipe clips insofar as, because of their configuration, they are prone to deformation during adjustment and tensioning of the strap which can lead to looseness of the clip thereby allowing rotation or other movement of the clip about the pipe when any force is applied. Failure of a proper earth connection to the pipe can lead to dangerous situation if for any reason the pipe become live. A further problem is that with conventional pipe clips, it is usually necessary to provide different electrical terminals thereon to accommodate different cable sizes.

This can provide an opportunity for a pipe clip with an inappropriate terminal to be used leading to a possible inadequacy in the earth connection.

It is an object of the present invention to provide an improved earth connection for pipes which overcomes or at least minimises the above

mentioned problems.

Thus and in accordance with the present invention therefore there is provided an improved earth connection for pipes comprising a body to receive an earth connector in electrical connection thereto and an adjustable fastening means to adjustably secure said body in electrical connection with a pipe, wherein said body includes fixing means which positively locates said body relative to the pipe and prevents movement of said body reiative 10 The pipe.

With this arrangement it is possible to provide an earth connection for pipes which is secure and less prone to failure thereby increasing safety.

Preferably the fixing means comprises at least two projections provided on the body which positively engage a surface of the pipe to prevent relative movement between the pipe and the body.

The body may also include spread resistance means which acts to resist the spread of the body as the fastening means IS adjusted and the body is secured in position relative tot he pipe. Preferably, the spread resistance means are urged by the strap during tensioning thereof towards the pipe thereby obviating spread. Spread of the body as the body is fixed in position could lead to a compromise in the integrity of the earth connection. Most preferably, the spread resistance means comprises a pair of wing members projecting from at least a part of the body, preferably adjacent to the pipe, which when fixed in position, are urged towards the

pipe by the strap.

Preferably the body includes two parts, a cable retention part and a pipe engaging part, said parts being interconnected by an adjustable fastener and an electrical connection is made by constraining an earthed conductor between said cable retention part and said pipe engaging part.

The invention will now be described further by way of example only and with reference to the accompanying drawings of which : - Figs. la to 1d show a prior art form of pipe clip in schematic form ; Fig. 2 show a prior art form of pipe clip of the type shown in Figs. 1 a and 1 d mounted for multiple earth bonds; Figs. 3a to 3c show one embodiment of approved pipe clip according to the present invention in schematic form; and Fig. 4 show the embodiment of Figs. 3 a to 3c mounted on a pipe for multiple earth connection.

Referring now to the Figures there is shown in Figs 1 a to 1 d a pipe clip of conventional form.

The pipe clip 10 comprises a body 11 to which is attached an electrical termination 12. The body 11 has an aperture 13 in each side wall 14 thereof through which a fastening strap 16 can pass in a manner to be described hereinafter. A screw threaded fastener 17 passes through a bore in a top surface of the body 11 and is held in position by a nut 18 which bears against the top surface of the body 11.

The electrical termination 12 (shown more clearly in Fig. 1 b) is of conventional form and comprises a hollow cylindrical member 19 which includes a bearing surface 21. A suitable fastener 22 passes through a bore 23 in the bearing surface 21, the fastener 22 having an enlarged head 24 which is a close fit in the bore in the hollow member 19.

Projecting feet 26 are provided on a bottom surface of the body 11 which facilitate location of the clip when mounted on a pipe.

In use, the clip is secured to a pipe as shown in Fig. 1 d In which the electrical termination is omitted for clip. A flexible fastening strap 16 IS passed through the aperture 1 3 In one side wall 14 of the body 11 and then out of the body 11 through the aperture 13 in the other side wall 14 of the body 11. The strap 1 6 is then passed around the pipe to which the clip is to be secured and is then once again passed through the aperture 13 in one side wall 14 of the body 11. It will be appreciated that if the strap 16 is passed through the body 11 in this way, there will be a double thickness of strap 16 in the body 11 between the apertures 13. The screw threaded fastener 1 7 can then be tightened so as to bear against the double thickness of strap until the fastener 17 holds the strap 16 in position against a bottom surface of the body 11. The action of tightening the fastener 17 will also tighten the strap 16 against the pipe ensuring the clip 10 is held in position relative to the pipe under tension. Once the clip 10 is in place, an earth conductor 28 connected to a suitable electrical earth is stripped at one end

and is connected between the bearing surface 21 of the electrical terminal 1 2 and the enlarged head 24 of the fastener 22 whereby tightening of the fastener will hold the conductor between the head 24 and the bearing surface 21.

Once fixed in this position, the pipe is electrically earthed through the earth conductor.

Where it is necessary to electrically earth more than one pipe in close proximity, the conventional clip can be used to"cross bond" (i. e. linking to earth) more than one proximate pipe as shown in Fig. 2. It can be seen that the earth conductor 28 is used to link all of the pipes together with one of the pipes being connected to electrical earth in the manner shown in the Figure.

Whilst in most circumstances, conventional clips provide a relatively secure and safe earth connection to pipes, problems have been encountered.

Firstly, with conventional clips of the type described above, it is possible to over tighten the fastener 17 which can result in the body 11 being deformed.

This can lead to the projecting feet 26 losing engagement with the surface of the pipe allowing rotational or other movement of the clip relative to the pipe. This will obviously effect the integrity of the earth connection and could reduce safety. Furthermore, if only one earth conductor is connected to the electrical termination 12, the fastener 17 may be deflected at an angle and therefore may not provide a positive or firm enough grip on the

conductor. In order to deal with this problem, it has become necessary to provide a crimped ring over the fastener to ensure that the connection is held firmly in position. It is possible for this crimped ring to not be fitted by oversight which leads to problems with integrity of the earth connection.

Still further in order to deal with different sizes of conductor it is necessary to provide clips having different sized electrical terminations 12 in order to ensure that the electrical termination 12 has a size suitable to secure the size of cable being used in such a way as to provide a satisfactory and safe connection. If the wrong sized clip is used, integrity of the connection can be compromised.

The present invention seeks to overcome these problems.

One embodiment of clip according to the present invention IS shown in Figs. 3a to 3c.

The clip 100 comprises a generally U shaped cable retaining part 101 and a pipe mounting part 102, also of generally U shape. The cable retaining part 101 and the pipe mounting part 102 have apertures provided therein which can be aligned to allow a screw threaded fastener 103 to extend through the hole in the respective parts as shown in Fig. 3a. The pipe mounting part 103 has transversely extending wing members 104 projecting therefrom which project outwardly from the pipe mounting part 102. The wing members 104 have at least one projecting tooth 106, in the embodiment shown in the drawings two such teeth are provided, one on

each wing member for a purpose to be described hereinafter. Each side wall 107, 108 of the pipe mounting part 102 and the cable retaining part 101 have 109, 110 apertures therein, the apertures 109, 110 in the side walls 107, 108 of the respective parts 101, 102 can also be aligned to provide a continuous passage through the walls 107, 108 of the cable retaining part 11, and the pipe mounting part 12 into the interior of the pipe mounting part 12 and out through the opposite walls 107, 108 of the pipe mounting part 12 and the cable retaining part 11.

At the intersection of the side walls 108 of the pipe mounting part and the wing members 104, projecting teeth 106 are provided for a purpose to be described hereinafter.

In use, the pipe mounting part 11 and the cable retaining part 12 are fastened together using the fastener 17 as shown in Figs. 3a and 3b. The parts 11, 12 are secured in such a manner that the apertures 109 in the side walls 107, 108 of the parts are aligned. The connected cable retaining part 12 and mounting part 11 are then located on a pipe to which they are to be connected and a flexible fastening strap 112 is passed through the aligned apertures 109, in the side walls of the pipe mounting part and the cable retaining into the interior of the pipe mounting part and out through the aligned apertures in the opposite side of the parts 102, 103. The strap is then passed around the pipe and, as shown in Fig. 3a, is passed once again into the interior of the pipe mounting part 102 though the aligned apertures

in the side walls of the pipe mounting part and the cable extending part. The free end of the strap is pulled tight and then down. As in the conventional pipe clip, it will be appreciated that by passing the retaining strap 11 2in this way, there will be two thicknesses of the strap in the interior of the pipe mounting part and the fastener is then tightened until It engages the strap.

The tightening of the fastener 107 into engagement with the strap 1 12 causes tightening of the strap around the pipe holding the clip firmly In piace.

Furthermore, with the pipe clip of the Invention, the strap 112 passes around the wing members 104 and therefore when tightened, it urges the wing members 104 Inwardly which negates as spreading problem encountered by over tightening of the conventional clips. Still further, projecting teeth 106 on the pipe mounting part 102 also give use to a positive engagement of the clip to the pipe and assist In resisting clip movement relative to the pipe. An electrical earth conductor can be connected to the clip by stripping the end of the conductor 113 connected to electrical earth, placing the stripped end between an upper surface of the pipe mounting member 102 and the cable retaining member 101 and tightening nut 114 until the cable retaining member 101 bears against the stripped end of the conductor and the conductor is firmly held between the cable retaining part 101 and the upper surface of the pipe mounting part 102. This type of connection will clearly allow connection of cables of different sizes using the same pipe clip and therefore only one type of pipe clip needs to be provided to cater for all

circumstances obviating the problems of using incorrect size or type of clip leading to problems with integrity of the connection.

Furthermore, using the clip of the invention, cross bonding is also simplified since, as shown in Fig. 4, it is a simple matter of stripping a long length of an earth conductor and feeding it between the cable retaining parts 101 and pipe mounting parts 102 of pipe clips linked provided on proximate pipes. The cable retaining parts 101 can then be secured in position to retain the earth conductor in position by tightening nuts 114 on each of the clips.

It is of course to be understood that the invention is not intended to be restricted to the details of the above embodiment which are described by way of example only.

Claims

CLAIMS 1. An improved earth connection for pipes comprising a body to receive an earth electrical connection thereto and an adjustable fastening means to adjustably secure said body in electrical connection with a pipe, wherein said body includes fixing means which positively locates the body relative to the pipe and prevents movement of said body relative to the pipe.
2. An improved earth connection according to Claim 1 wherein the fixing means comprising two projections provided on the body which positively engage a surface of the pipe to prevent relative movement between the pipe and the body.
3. An improved earth connection according to Claim 1 or Claim 2 further Including spread resistance means which acts to resist the spread of the body as the fastening means is adjusted and the body is secured in position relative to the pipe.
4. An improved earth connection according to Claim 3 wherein the spread resistance means is urged by the strap during tensioning thereof towards the pipe therefore obviating spread.
5. An improved earth connection according to Claim 3 or Claim 4 wherein the spread resistance means comprising a pair of wing members projection from at least part of the body, preferably adjacent to the pipe, which when fixed in position, are urged towards the pipe by the strap.
6. An improved earth connection according to any one of Claims 1 to 5 wherein the body includes two parts, a cable retention part and a pipe engaging part, said part being interconnected by an adjustable fastener and an electrical connection is made by constraining an earthed conductor between said cable retention part and said pipe engaging part.
7. An improved earth connection according to any preceding claims substantially as hereinbefore described with reference to the accompanying drawings.