EP0841717A2

EP0841717A2 - Electrical connector

Info

Publication number: EP0841717A2
Application number: EP97309014A
Authority: EP
Inventors: Iain Malcolm Strachan
Original assignee: CCL Systems Ltd
Current assignee: CCL Systems Ltd
Priority date: 1996-11-09
Filing date: 1997-11-10
Publication date: 1998-05-13
Also published as: EP0841717A3; GB9623361D0

Abstract

The invention concerns an electrical connector for providing a connection to an insulated overhead powerline. The connector comprises the sleeve member (1) having a removable portion (2) and a connection point (6) for connecting an external conductor thereto. The electrical connector includes insulation piercing means which is activated upon compression of the connector using a standard compression tool. Various embodiments of connector are described herein, including embodiments which do not feature a removable portion (2) but which, instead feature a sleeve member of essentially U-shaped construction which may be compressed directly onto an overhead powerline.

Description

The invention relates to electrical connectors. In particular, the invention relates to connectors for connecting to insulated conductors for air lines.
In many circumstances it is required to provide a connection to existing overhead power lines. Prime considerations when making such connections are naturally that the connection should be made in a safe and reliable manner.
To improve the safety and reliability of overhead lines, insulated lines are in use and this invention is primarily (although not exclusively) directed towards forming a connection to such insulated lines.
In order to provide a connection to an insulated overhead line, it is necessary to somehow pierce the insulation surrounding the conductor. Typically, such piercing is carried out by providing a two-piece clamping arrangement to fit around the overhead line, the two pieces being joined together by a bolt or the like which, as it is tightened, brings opposing jaws of the clamping arrangement together. As the jaws close, teeth on the jaws pierce the insulating layer and establish a connection. This type of connector may be arranged so that as the two parts are drawn together, they also enclose an extra element to which external connection may be made for tapping the conductor. In many situations, the connector forms a spark protection device and the external connection is a so-called sparking horn.
The external connection to the power line is usually taken off in the form of a connection which is parallel to the main overhead line. Environmental conditions often cause the lines to move around with the wind and when this occurs, chaffing can be a problem at the point of external connection.
A further disadvantage with known connectors is that because of their multi-part construction, they can be awkward to attach to the overhead lines.
According to a first aspect of the invention, there is provided an insulation piercing electrical connector, the connector comprising a sleeve member having a longitudinal opening formed therein to allow the sleeve member to be passed over an elongate insulated conductor, the connector further comprising an external conductor connection point for connecting an external conductor thereto, the connector being characterised in that the sleeve member is provided with means for piercing the insulation of the insulated conductor once the connector is in place, piercing being achieved by mechanical deformation of the sleeve member onto the insulated conductor.
The sleeve member is preferably U-shaped in cross-section.
The means for piercing preferably comprise a plurality of protrusions. The protrusions may comprise U-shaped ridges longitudinally spaced apart from one another and internally arranged within the sleeve member.
In preferred embodiments of the invention, the connector may be provided with a removable section which, when present, cooperates with the sleeve member to enable a part of the elongate insulated conductor to be completely enclosed.
Preferably, the removable portion forms a sliding fit with a main part of the sleeve member.
Preferably, the means for piercing the insulation of the conductor are provided on the interior of the sleeve member and comprise one or more protrusions such that as a portion of the sleeve member adjacent to a protrusion is compressed, the protrusion pierces the insulation to establish electrical connection.
Preferably, there are provided a plurality of protrusions on the interior of the sleeve member. The protrusions may be arranged longitudinally. In an alternate preferred embodiment, the protrusions are substantially transversely arranged and longitudinally spaced from one another along the sleeve member.
Preferably, the sleeve member is provided with one or more external indentations, so that a compression tool may be fitted externally to the sleeve member and located on said indentation or indentations.
Preferably, the or each external indentation has a corresponding internal protrusion in radial alignment with it with respect to a central longitudinal axis of the sleeve member.
Preferably, once the compression tool has been located and compression is being applied, the compression force acts via the or each indentation to force the or each protrusion through said insulation.
Preferably, the removable portion is connected to the main part of the sleeve member by means of a groove and tongue type fitting.
The groove and tongue type fitting may comprise one or more tongues formed in the removable portion for cooperation with one or more grooves formed in the main part of the sleeve member. Alternatively, this groove and tongue configuration could be reversed so that the tongue is on the main part of the sleeve member and the groove is on the removable portion. Preferably the tongue and groove connection is in the form of a dove-tail connection.
Preferably, the sleeve member is of constant cross-section throughout the major part of its length, said internal protrusion or protrusions and external indentation or indentations also being provided along the major portion of the sleeve members length.
Preferably, the external conductor connection point extends substantially at right angles to the sleeve member.
Preferably, there are a plurality of indentations and a plurality of corresponding protrusions, the indentations and protrusions extending along a major portion of the sleeve members length.
Preferably, the external conductor connection point and sleeve member form a T-type connection. The external conductor connection point also comprising a sleeve like member into which an external conductor may be connected by compression.
Compression of the external conductor connection point may be carried out on-site or, alternatively, the external conductor may be pre-connected to the connection point.
The external conductor may comprise a spark arrester element, such as a spark arrester horn.
Preferably, the external conductor includes an enlarged portion which, during the compression operation, is trapped within the external conductor connection point. Trapping of the conductor in this way may be arranged so as to allow the external conductor to be rotated with respect to the connection point, but not to allow the conductor to be withdrawn therefrom.
When the external conductor is a spark arrester element, the electrical connector provides an arc-protection device for the insulated conductor.
By having a connector as described above with a sleeve member having a removable portion, the connector can be offered up to the insulated conductor without needing to cut the insulated conductor.
For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example, to the accompanying diagrammatic drawings, in which:

Figure 1 shows a side view, partly in section of a first embodiment of the electrical connector of the present invention;
Figure 2 is an end view of the first embodiment shown in Figure 1;
Figure 3 is an end view of a second embodiment of the electrical connector of the present invention;
Figure 4 illustrates a manner in which embodiments of the present invention may be connected to an overhead air line and also shows a spill takeoff;
Figure 5 is a plan view of a third embodiment of the electrical connector of the present invention;
Figure 6 is a view from arrow A of the connector of Figure 5;
Figure 7 is a view from arrow B of the connector of Figure 5;
Figure 8 shows a simplified form of the connector of Figures 5 to 7;
Figure 9 is yet another possible embodiment similar to the embodiment of Figure 8, but including longitudinally running protrusions; and
Figure 10 illustrates how the connector may be compressed.

Referring initially to Figures 1 and 2, a first embodiment of an electrical connector in accordance with the present invention is shown.
The connector comprises a sleeve member 1 having a removable portion 2 attached by means of a tongue and groove type connection 3 so that the removable portion 2 is a sliding fit with a main part 4 of the sleeve member 1. In the embodiment shown, the removable portion 2 has a longitudinally extending indentation 5 which may extend along the whole length of the removable portion. The sleeve member connects to a external conductor connection point 6 and joins with it at right angles. The connection point 6 is adapted to receive either an electrical conductor in the form of an electrical lead or items such as a spark arrester horn 7 therein. The connection point 6 is joined to the sleeve member 1, for instance, by a butt welding operation.
Whilst the embodiment of Figure 2 shows a single longitudinally extending protrusion or indentation 5 formed on the removable portion 2, it will be appreciated that a plurality of such protrusions or indentations 5 may be provided extending in the longitudinal direction and radially spaced from one another to improve connection to the conductor. Also, it will be appreciated that whilst these protrusions of indentations 5 are shown as being formed on the removable portion, they may alternately be formed on the main part 4 of the sleeve member 1. Also, instead of running longitudinally, transversely arranged protrusions or indentations 5 may be provided longitudinally spaced from one another along the length of the sleeve member 1.
Connection of the electrical connector to an overhead line will now be described.
In order to join the connector to an overhead line, the removable portion 2 is first removed. The connector may be then be offered up to the overhead line and the overhead line received within the main portion 4 of the sleeve member. With the sleeve member sitting in the main part 4 of the sleeve member, the removable portion may then be connected therewith by sliding it onto the main part 4, by means of the tongue and groove fittings 3. Performing this operation makes a loose connection with the insulated conductor. In order to pierce the insulation of the conductor the sleeve member 1 must be radially compressed so that indentation 5 pierces the insulation layer of the conductor and makes an electrical connection therewith. The connector is then secure on the overhead line. The spark arresting horn 7, or conductor as required, may be attached to the external connection point by inserting it therein and then performing another compression operation. Preferably, the conductor/spark arrester horn has an enlarged head which, during the compression operation upon the external connection point, is trapped within the connection point 6, so as to prevent withdrawal but allowing rotation of the conductor/spark arrester horn with respect to it.
By providing the external connection point 6 substantially at right angles to the sleeve member, less chaffing of the conductor/spark arrester horn occurs during adverse weather conditions.
Referring now to Figure 3, a preferred form of the sleeve member 1 is shown. The external conductor connection point 6 has been omitted from this drawing for clarity, but would extend from the sleeve member 1 in the same manner as shown in Figures 1 and 2. The sleeve member 1 of Figure 3 has a main part 4 and a removable portion 2 which are connected to one another by tongue and groove connections such as dove-tail joints 8.
In contrast to the embodiments of Figures 1 and 2, the sleeve member of Figure 3 is not of a substantially circular cross-section but instead features internal protrusions 9 and external indentations 10.
In use, the insulated conductor is introduced into the sleeve member in similar fashion to that required of the Figure 1 and 2 embodiment, i.e. removable section 2 is removed and the main part 4 of the sleeve member placed around the insulated conductor prior to replacing the removable section 2. The particular cross-sectional shape of the sleeve member 1 is chosen so that an external compression tool may be located upon the indentations 10 and as the tool compresses the sleeve member 1, protrusions 9 bite into the insulation of the insulated conductor so as to pierce it. Each indentation 10 has a corresponding protrusion 9 which is radially aligned therewith with respect to a central longitudinal access of the sleeve member. In this manner, as the compression occurs force is directed efficiently through each indentation 10 into its corresponding protrusion 9.
The indentations and protrusions may extend along a full length of the sleeve member 1.
Figure 4 shows a typical application of the device in schematic form. In the illustration, insulated overhead conductors 11 to 13 are shown connected to a pylon 14 with a transformer 15 at the base thereof. A pair of electrical connection devices are shown each being connected to a respective overhead cable 11 and 12. The Figure also shows what is known as a "spill takeoff" connected to the electrical connection devices and leading down to transformer 15. Such spill takeoffs may be attached by providing a conductor 16, 17 from the transformer 15 and clamping the end of the conductor 16, 17 to the spark arrester horns 7 of the devices. Attachment of the conductors 16, 17 to the spark arrester horns 7 may be achieved by a clamp connection, the clamp being actuated by an operative having an insulated rod 18 which connects with a bolt or similar part 19 of a clamping member 20. The clamping member may be offered up to the spark arrester horn 7 by the operative holding the insulated rod 18 and attaching the spark arrester horn by the operative rotating the rod 18 until the clamp is tightly connected to the spark arrester horn.
Referring now to Figures 5 to 7, there is shown a third embodiment of an electrical connector.
The connector of Figures 5 to 7 comprises an elongate sleeve member 21 of essentially U-shaped cross-section having a plurality of longitudinally spaced apart transversely extending indentations or protrusions 22 to 24. An external conductor connection point 25 is provided and this is shown in the form of a hollow tube into a cavity 26 of which an external conductor of the type 7 shown in Figure 1 may be introduced. The external conductor connection point 25 is a compression fixing, so that once an external conductor such as the spark arrester horn 7 has been introduced into the opening 26 the compression fixing may be compressed using a standard compression tool so as to trap the spark arrester horn 7 therein. As with the other embodiments, this compression operation may be arranged to trap an enlarged end of the horn 7 therein, but to allow the horn 7 to freely rotate with respect to the connection point 25.
In order to join the conductor of Figures 5 to 7 to an overhead line, the sleeve member 21 is offered up to the overhead line and the insulated conductor of the overhead line is fed into opening of the essentially U-shaped cross-section of the sleeve member 21. Then, in contrast to the first and second embodiments described above, instead of adding a removable portion to completely enclose the insulated conductor within the sleeve, the sleeve 21 is simply compressed using a compression tool. The compression of the sleeve 21 causes the protrusions 22 to 24 to bite into the insulation surrounding the conductor and make a connection with the conductor inside the insulation of the overhead line. It will be appreciated that the compression operation causes the U-shaped cross-section to deform and wrap around the insulated conductor to a certain degree so that the connection to the overhead line is stable.
Figures 8 and 9 show two further embodiments of electrical connector.
The embodiment of Figure 8 is similar to the embodiment of Figures 5 to 7 and like reference numerals are used where appropriate.
The principal difference between the embodiment of Figure 8 and the embodiment of Figures 5 to 7 is that the external conductor connection point 25 comprises a flat plate having a pair of apertures 27, 28 formed therein which are tapped to receive a screw or similar. By means of the threaded apertures 27, 28 an external conductor may be connected or clamped directly to the connector.
The embodiment of Figure 9 is very similar to that of Figure 8 except that the protrusions 22-24 are arranged to run longitudinally within the sleeve member 21.
Referring now to Figure 10, there is illustrated how a compression tool may be used to compress a sleeve member of the types shown in Figures 5 to 9.
The compression tool 29 has an internal cavity 30 of complimentary form to the external formation of the sleeve member 21 of the electrical connector. When compressing the sleeve member 21, pressure is applied from four points A, B, C and D so as to force the sleeve member to close up around the insulated conductor and urge the protrusions 22-24 through the insulation into contact with the conductor.
It will be appreciated that various other modifications to the electrical connectors of the present invention may be made with departing from the scope of the invention. In particular, different forms of insulation piercing protrusions may be provided and, instead of connecting a spark arrester horn, other connections to the conductors may be made.
The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.
All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.
Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.
The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

An insulation piercing electrical connector, the connector comprising a sleeve member (1, 21) having a longitudinal opening formed therein to allow the sleeve member (1) to be passed over an elongate insulated conductor, the connector further comprising an external conductor connection point (6, 25) for connecting an external conductor (7) thereto, the connector being characterised in that the sleeve member (1) is provided with means (5, 22-24) for piercing the insulation of the insulated conductor once the connector is in place, piercing being achieved by mechanical deformation of the sleeve member (1) onto the insulated conductor.
The connector according to Claim 1, wherein the sleeve member (1) is essentially U-shaped in cross-section.
The connector according to Claim 1 or 2, wherein said means for piercing comprises a plurality of protrusions (5, 22-24).
An insulation piercing connector according to Claim 1, 2 or 3, wherein a removable section (2) is provided, which, when present, cooperates with the sleeve member (1) to enable a part of the elongate insulated conductor to be completely enclosed.
A connector according to Claim 4, wherein the removable portion (2) forms a sliding fit with a main part of the sleeve member (1).
A connector according to any of Claims 1 to 5, wherein the means for piercing (5, 22-24) are provided on the interior of the sleeve member (1, 21) and comprise one or more protrusions (5, 22-24) such that as a portion of the sleeve member adjacent to a protrusion (5, 22-24) is compressed, the protrusion (5, 22-24) pierces the insulation to establish electrical connection.
A connector according to Claim 6, wherein a plurality of protrusions (5) are provided on the interior of the sleeve member (1) and arranged longitudinally with respect to the sleeve member (1).
A connector according to Claim 7, wherein a plurality of protrusions (22-24) are provided substantially transversely arranged and longitudinally spaced from one another along the sleeve member (21).
A connector according to any of the preceding claims, wherein the sleeve member (1) is provided with one or more external indentations (10) upon which a compression tool may be located.
A connector according to Claim 9, wherein the or each external indentation (10) has a corresponding internal protrusion (9) arranged in radial alignment with it with respect to a central longitudinal axis of the sleeve member (1).
A connector according to Claim 10, wherein during compression, the compression force acts via the or each indentation (10) to force the or each protrusion (9) through said insulation.
A connector according to any of the preceding claims, wherein the external conductor connection point (6) extends substantially at right angles to the sleeve member (1).
A connector according to any of the preceding claims, wherein the external conductor connection point (6) comprises a sleeve into which an external conductor (7) may be connected by compression.
A connector according to any of the preceding claims, wherein the external conductor comprises a spark arrester element.
A connector according to any of the preceding claims, wherein the external conductor includes an enlarged portion which, in use, is trapped within the external conductor connection point.