GB2319401A

GB2319401A - Clamp for sheath of electric cable

Info

Publication number: GB2319401A
Application number: GB9721218A
Authority: GB
Inventors: David John Hollick
Original assignee: B & H Ltd
Current assignee: B & H Ltd
Priority date: 1996-11-08
Filing date: 1997-10-08
Publication date: 1998-05-20
Anticipated expiration: 2017-10-08
Also published as: GB9721218D0; GB9623292D0; GB2319401B

Abstract

An electrical connector comprises a contact member formed from a sheet of resilient, electrically conducting material. A major portion thereof is formed into a part tubular cable-receiver (2), into which a first electrical conductor having an electrically conducting outer sheath may be inserted. A minor portion of the sheath is formed into a tongue (3) to which a second electrical conductor can be clamped. Means (5,6,7) such as a jubilee clip are provided for tightening the cable-receiver (2) into circumferential engagement with the first electrical conductor.

Description

Title - Electrical Connector This invention relates to an electrical connector, and in particular to an electrical connector of the type known as a sheath clamp.

Certain forms of electrical conductor are provided with an electrically conducting outer sheath.

One example is lead-sheathed cable which, though now not as extensively used as in the past, still finds application in certain areas. Problems are encountered in forming electrical connections with such lead-sheathed cable, in particular due to the difficulty in establishing good electrical contact with the lead sheath, which in the past has required soldering or plumbing with hot molten solder which is a skilled, dangerous and expensive operation.

There has now been devised an improved form of electrical connector, which overcomes or substantially mitigates the above-mentioned disadvantage.

According to the invention, an electrical connector comprises a contact member formed from a sheet of resilient, electrically conducting material and having a major portion thereof formed into a part tubular cable-receiver positioned, in use, around a first electrical conductor having an electrically conducting outer sheath, and a minor portion thereof formed into a tongue to which a second electrical conductor can be clamped, and means for tightening, in use, the cable-receiver into circumferential engagement with the first electrical conductor.

The connector according to the invention is advantageous primarily in that excellent electrical contact can be achieved between the cable-receiver and the first electrical conductor.

Nonetheless, the connector is of relatively simple form and, as described below, can be economically manufactured. Also, the connector may be used with readily available clamps designed for use with modern cable types.

The contact member is preferably of a metal with suitably high electrical conductivity. The most preferred material for the contact member is copper, which may be plated or unplated. For example, tinned copper may be used.

The means for tightening the cable-receiver is preferably a clamping band passing around the cable-receiver. Most preferably, the tightening means is a so-called "jubilee clip". The clamping band is most preferably retained around the cable receiver by being passed through an opening in the tongue portion of the contact member.

The contact member is preferably cut as a series of blanks from a sheet of suitable material, such as copper. It is found that the contact member can be produced in a particularly economical fashion, with no waste of material, if the contact member blank is L-shaped, the shorter limb of the L-shaped blank having a length substantially equal to the width of the longer limb. The longer limb is subsequently bent to form the cable receiver, and the shorter limb represents the tongue. The cable receiver may be formed by this bending operation either by the manufacturer or by the installer of the connector.

The invention will now be described in greater detail, by way of illustration only, with reference to the accompanying drawings, in which Figure 1 is a side view of a first embodiment of a sheath clamp according to the invention; Figure 2 is a view along the arrow H in Figure 1; Figure 3 illustrates a first manner of cutting blanks used in the manufacture of the sheath clamp of Figure 1; Figure 4 illustrates a second manner of cutting blanks used in the manufacture of the sheath clamp of Figure 1; and Figure 5 is a view similar to Figure 2 of a second embodiment of a sheath clamp according to the invention.

Referring first to Figures 1 and 2, a sheath clamp (generally designated 1) comprises a tubular contact element 2 dimensioned to receive a lead-sheathed cable (not shown). The contact element 2 is formed from an L-shaped blank cut from a sheet of copper in the manner described below.

The greater part of the longer limb of the blank is formed into the tubular contact element 2, the remaining part 2a upstanding from the contact element 2 and connecting the contact element 2 to a tongue 3 formed by folding of the shorter limb of the blank. The folding of the tongue 3 is important since it increases the effective cross-sectional area of the current path, and hence the current-carrying capacity of the sheath clamp 1, and also the mechanical strength of the clamp.

In practice, it may be convenient for forming of the longer limb of the blank into the tubular contact element 2 to be performed by the installer of the clamp, the clamp being supplied by the manufacturer with the longer limb of the blank in a flat condition, and the installer then cutting the longer limb to the desired length and bending it around the lead sheath of the cable.

The upstanding part 2a is provided with an aperture 4 through which is passed the strap 5 of a jubilee clip 6. The jubilee clip 6 is of conventional construction and includes a tightening screw 7 by which the clip 6 can be used to reduce the diameter of the tubular contact element 2 and hence to bring it into engagement (and electrical contact) with a sheathed cable received within it.

In use, the sheath clamp 1 of Figure 1 is used to form a connection between a lead-sheathed cable and another conductor as follows. First, the tubular contact element 2 is positioned around the lead-sheathed cable, either by opening the tubular contact element 2 sufficiently to allow it to be passed around the cable or, if the tubular contact element is supplied flat, by forming it into a tubular configuration around the cable. The strap 5 of the jubilee clip 6 is then passed through the aperture 4 and engaged with the clip 6. The jubilee clip 6 is then tightened to bring the contact element 2 into circumferential engagement with the lead sheath. The other conductor is then clamped to the tongue 3 using any suitable clamping device. The other conductor may, for example, be copper wires of a second cable.

Figure 3 shows how L-shaped blanks for use in the manufacture of the sheath clamp 1 can be cut from a ribbon of copper. Reference numerals in Figure 3 indicate the parts of the contact element which are formed from the blank. Blanks may be cut from a sheet of copper in a similar arrangement (ie as if the sheet comprises a number of adjacent ribbons as shown in Figure 3).

Figure 4 shows an alternative arrangement. It will be noted that in all of these arrangements (in which the length of the shorter limb of the blank is the same as the width of the longer limb) there is no wastage of material. Figures 3 and 4 show the apertures 4 through which the strap 5 ofthejubilee clip 6 is passed. These apertures may alternatively be cut in a separate step, after formation of the blanks.

Finally, Figure 5 shows a second embodiment of a sheath clamp which is identical to that of Figures 1 and 2, save that the plane of the tongue 30 is disposed radially to the clamping element 20. In the embodiments of both Figure 2 and Figure 5 the jubilee clip may of course occupy any position around the circumference of the contact element.

Claims

1. An electrical connector comprising a contact member formed from a sheet of resilient, electrically conducting material and having a major portion thereof formed into a part tubular cable-receiver positioned, in use, around a first electrical conductor having an electrically conducting outer sheath, and a minor portion thereof formed into a tongue to which a second electrical conductor can be clamped, and means for tightening, in use, the cable-receiver into circumferential engagement with the first electrical conductor.

2. A connector as claimed in claim 1, wherein the contact member is of plated or unplated copper.

3. A connector as claimed in claim 1 or claim 2, wherein the means for tightening the cablereceiver is a clamping band passing around the cable-receiver.

4. A connector as claimed in claim 3, wherein the clamping band is retained around the cable-receiver by being passed through an opening in the tongue portion of the contact member.

5. A connector as claimed in any preceding claim, wherein the contact member is cut as a series of blanks from a sheet of suitable material.

6. A connector as claimed in any preceding claim, wherein the contact member is formed from an L-shaped blank, the shorter limb of the L-shaped blank having a length substantially equal to the width of the longer limb.

7. A method of forming a connector as claimed in claim 6, which method comprises cutting an L-shaped blank from a sheet of material, the shorter limb of the L-shaped blank having a length equal to the width of the longer limb, and bending the longer limb to form the cablereceiver.

8. An electrical connector substantially as hereinbefore described and as illustrated in Figures 1 and 2.

9. A method of forming an electrical connector, substantially as hereinbefore described.

9. An electrical connector substantially as hereinbefore described and as illustrated in Figure 3.

10. A method of forming an electrical connector, substantially as hereinbefore described.

Amendments to the claims have been filed as follows 1. An electrical connector comprising a contact member formed from a sheet of resilient, electrically conducting material and having a major portion thereof formed into a part tubular cable-receiver positioned, in use, around a first electrical conductor having an electrically conducting outer sheath, and a minor portion thereof formed into a tongue to which a second electrical conductor can be clamped, and a clamping band passing around the cable-receiver for tightening, in use, the cable-receiver into circumferential engagement with the first electrical conductor.

3. A connector as claimed in claim 1 or claim 2, wherein the clamping band is retained around the cable-receiver by being passed through an opening in the tongue portion ofthe contact member.

4. A connector as claimed in any preceding claim, wherein the contact member is cut as a series of blanks from a sheet of suitable material.

5. A connector as claimed in any preceding claim, wherein the contact member is formed from an L-shaped blank, the shorter limb ofthe L-shaped blank having a length substantially equal to the width of the longer limb.

6. A method of forming a connector as claimed in claim 5, which method comprises cutting an L-shaped blank from a sheet of material, the shorter limb of the L-shaped blank having a length equal to the width of the longer limb, and bending the longer limb to form the cable-receiver.

7. An electrical connector substantially as hereinbefore described and as illustrated in Figures 1 and2.

8. An electrical connector substantially as hereinbefore described and as illustrated in Figure 3.