GB2274215A

GB2274215A - Coupling earth rods

Info

Publication number: GB2274215A
Application number: GB9326474A
Authority: GB
Inventors: John Leslie Bilbie
Original assignee: EAST MIDLANDS ELECTRICITY PLC
Current assignee: EAST MIDLANDS ELECTRICITY PLC
Priority date: 1993-01-09
Filing date: 1993-12-24
Publication date: 1994-07-13
Anticipated expiration: 2013-12-24
Also published as: GB2274215B; GB9326474D0; GB9300346D0

Abstract

A coupler (10) for earth rods (R) comprises a generally cylindrical body (12) with a threaded passage formed therethrough. The enlarged central region (26) of the body has a plurality of flats (28 Figures 2 to 4) formed thereon such that a spanner can be applied to the body to tighten it against earth rod sections threadably mounted therein. Dimples (38) may be punched or pressed in the body to deform the threads in the passage to lock the rods therein. <IMAGE>

Description

Improvements in or relating to couplers This invention relates to couplers, particularly but not exclusively to couplers for coupling together earth rods.

For ease of handling, storage and installation earth rods are normally manufactured in lengths which are shorter than the length required in use. In order to obtain a rod of the desired length, it is necessary to couple several rods together. Known couplers have the disadvantage that it is difficult to ensure that they securely couple the rods together.

It is an object of the invention to obviate and/or mitigage this disadvantage.

According to this invention, there is provided a coupler for coupling together two elongate members, the coupler comprising a body having a threaded passage leading from each end, each passage being adapted to receive a respective one of the elongate members the body being provided with a plurality of planar portions arranged about the surface thereof to facilitate tightening the coupler onto the elongate members.

Preferably the threaded passages are co-axial and continue one into the other.

Preferably the threads in the passage are deformed over part of their length to provide an interference fit with an elongate member engaged therewith. Preferably the deformation is provided by forming a recess in the outer surface of the body in the region of the threaded passage by the application of impact or pressure.

The coupler is advantageously used as an earth rod coupler and in such a use, the elongate members are in the form of earth rods having a threaded portion corresponding to the threaded passage in the coupler at each of their ends.

The body may be substantialily cylindrical in configuration, the or each passage being co-axial therewith. Preferably, the body is provided with an enlarged central region upon which the substantially planar portions are arranged. Preferably the substantially planar portions extend circumferentially around the region. Advantageously, the substantially planar regions define, in cross-section, a substantially regular hexagonal configuration around the central region of the body.

Preferably when the passages are continuous regions at each end thereof are provided-with a shoulder spaced inwardly from the respective ends.

An embodiment of the present invention will now be described by way of example only with reference to the accompanying drawings, in which: Fig. 1 is a sectional side elevation of a coupler and the ends of rods which it is intended to couple together.

Fig. 2 is an end elevation of the coupler; Fig. 3 is a plan of the coupler; and Fig. 4 is a sectional view taken on the line A-A of Fig. 3.

The drawings show a coupler for connecting two circular cross-section earth rods R of an earthing system together. The coupler is generally designated 10 and comprises a body 12 of generally cylindrical configuration, having at opposite ends thereof first and second apertures 14,16. A bore 30 extends from the aperture 14 to the aperture 16.

The body 12 is provided with an enlarged central region 26 which extends between the dotted lines labelled A and B. As can be seen from Figs. 3 and 4, the enlarged region 26 is provided with six substantially planar flats 28 which are arranged circumferentially around the main body 12. The raised flats 28 define a substantially regular hexagon in end view and permit the use of a suitably sized spanner placed around the central region 26.

In use, the coupler 10 is intended to couple together earth rods R inserted respectively in the first and second apertures 14,16. The bore has an internal thread 32 and corresponding threads 18 are formed on the end portions of the earth rods. The bore 30 is provided with shoulders 34,36 at each end of the end regions thereof, the shoulders 34,36 being spaced from the respective apertures 14,16. By tightening the coupler 10 onto the threaded end portions 18 of the earth rods, the two rods can be coupled together. By using a spanner on the central region 26 of the coupler, it can be ensured that the rods and the coupler are tightly screwed together thereby ensuring a good permanent electrical and mechanical connection.

Earth rods are driven into the ground and in some conditions, for example if the ground is hard or rocky the couplers can work loose.

A modification is illustrated in the drawings and provides a means for obviating or mitigating this problem. Indentations or dimples 38 having a conical cross-section are punched or pressed into the body 12.

There may be two sets of three dimples equi-spaced around the periphery of the body, each set being located fairly close to the central region 36 but spaced therefrom.

The dimples deform the metal of the body 12 and more especially the thread 32 and the co-operation of the deformed thread of the coupler with the undeformed thread of the rod produces a locking force. Clearly, the amount of deformation caused by the dimples must be fairly precise to cause, on the one hand, sufficient interference between the thread of the body and the threads of the rods while not unduly hindering the threaded interconnection between the coupler and rods.

Various other modifications may be made without departing from the scope of the invention. For example, the shoulders 34,36 in the embodiment shown in Fig. 1 could be omitted. Any suitable number of flats 28 could be provided on the enlarged central region 26.

Claims

Claims:

1. A coupler for coupling together two elongate members, the coupler comprising a body having a threaded passage leading from each end, each passage being adapted to receive a respective one of the elongate members, the body being provided with a plurality of planar portions arranged about the surface thereof to facilitate tightening the coupler onto the elongate members.

2. A coupler as claimed in Claim 1, in which the threaded passages are co-axial.

3. A coupler as claimed in Claim 1 or Claim 2, in which the threads in the or each passage are deformed over part of their length to provide an interference fit with an elongate member engaged therewith.

4. A coupler as claimed in Claim 3, in which the deformation is provided by forming a recess in the outer surface of the body in the region of the threaded passage by the application of impact or pressure.

5. A coupler as claimed in any one of the preceeding claims, in which the body is substantially cylindrical and is provided with an enlarged central region upon which the substantially planar portions are arranged.

6. A coupler as claimed in Claim 5, in which the substantially planar portions extend circumferentially around the region to define, in cross-section a substantially regular hexagonal configuration around the central region of the body.

7. A coupler as claimed in any one of the preceding Claims, in which the passages are provided with a shoulder spaced inwardly from the respective ends.

8. A coupler substantially as hereinbefore described with reference to the accompanying drawings.

9. Any novel subject matter or combination including novel subject matter herein disclosed, whether or not within the scope of or relating to the same invention as any of the preceding claims.