GB2073300A

GB2073300A - Cable clamps

Info

Publication number: GB2073300A
Application number: GB8010680A
Authority: GB
Original assignee: SEMITAG SOC ECON MIXTE TRANSPO; Malico SA
Current assignee: SEMITAG SOC ECON MIXTE TRANSPO; Malico SA
Priority date: 1980-03-29
Filing date: 1980-03-29
Publication date: 1981-10-14
Also published as: GB2073300B

Abstract

Suspension means for overhead electric power lines includes a cable 12 suspended substantially transversely of the line and having a flexible sheath and a clamp 2 having a body 3 with an oblong cross- section longitudinally extending passage 7 therethrough, the top edge 9 of the passage being adapted for support on the cable and being inclined relative to the bottom edge 10; a side opening 13 having a width at least equal to the diameter of the cable being provided in the body leading to the passage; a wedge 4 connected (at 5) to the body and having two relatively inclined top 14 and bottom faces corresponding to the inclined edges of the passage and intended for engagement in the body to clamp the cable therein: means 19 being provided on the body for supporting a line mounting device. <IMAGE>

Description

SPECIFICATION Improvements in or relating to cable clamps and suspension means for a power line The present invention is a suspension means for an elongate member.

The invention is concerned especially, but not exclusively with suspension for overhead electric power line and clamps for use in same.

Overhead electric lines are used in a great number of very different applications and, in particular, to supply public lighting or power vehicles such as mass transport vehicles requiring overhead contact lines.

Presently, each line has at its top a dovetail engaged every so often "straight" or "bend" mounting devices each of which is suspended, by means of accessories, from an isolator, the flange connections of which are attached to a steel cable, stretched transversely to the highway. Insulated again, this cable is attached at its ends to buildings or supports specially adapted and placed on the edge of the carriageway on which vehicles operate.

The standard solution described above is satisfactory but exhibits certain disadvantages, for example: The suspension and insulation devices have a high cost price, are bulky and have a substantial weight; the fitment of very varied accessories which are made entirely of metal requires a long time and also requires special attention to electrical insulation; finally, this large number of overhead parts requires permanent supervision and periodic maintenance.

The invention is intended to obviate or mitigate these disadvantages.

According to the present invention there is provided a suspension means for an elongate member comprising a suspended cable including a protection sheath made of flexible material and a clamp having an elongated body with a longitudinal passage which has an oblong cross-section and is defined by two substantially parallel and vertical edges, another edge adapted for support on the cable and an opposite edge inclined relative to said other edge so that the spacing between said two opposite edges differs at their ends, the body having mounting means for a line mounting device, a side opening having a width at least equal to the diameter of the said cable and wedge connected thereto and having two parallel faces and two faces inclined in relation to each other and forming an angle corresponding to the angle formed by the two opposite edges of the passage in the body, the wedge being intended to be engaged in the body to clamp the cable therein.

The clamp makes it possible to suspend the line directly from the cable by means of clamps, using the preferable properties of absorption of mechanical energy, flexibility and continuous electrical insulation of the synthetic cable.

The self-tightening quality of the clamp in the direction of tensile stress on the cable in the case of tension on a line stretched in a curve, gives the suspension means an excelient performance.

The suspension means also makes possible a lightening and a reduction in number of the constituent parts and considerably reduces maintenance on the overhead line.

Initially the body of the clamp is installed on the cable then the wedge is engaged in the body until it locks. This is advantageous bearing in mind the fact that the external surface of the cable made from a flexible material deforms at the time of tightening.

By virtue of the substantial length of contact between each clamp and the cable, there is a risk of deterioration of the cable although its external surface is flexible. This suspension means also offers, compared with existing means, the advantage of being fitted very rapidly without needing any tool and of not sliding off the cable when the line takes up bends or corners.

The body and wedge of the clamp are preferably made of synthetic material and are moulded simultaneously, a strand being provided which permanently connects the wedge to the body.

This arrangement is interesting in that it avoids the presence of an isolator which reduces the cost price of installation. In addition, the fact that one strand moulding integrally with the body and wedge connects these two elements permanently and prevents any risk of loss of the wedge on the occasion of handling prior to clamping.

From a practical point of view when a clamp is fitted on a curve in an overhead line, the opening in the side of the body is arranged on the inside of the curve, so that any tendency of the clamp to slide on the support cable guarantees the production of self-locking. This self-locking prevents any risk of displacement of the clamp on the support cable.

The passage edge supported on the cable is in the form of a semi-cylindrical surface having a radius corresponding to that of the suspension cable.

In addition, the face of the wedge intended to contact the cable is in the form of a cylindrical surface having an axis parallel to the longitudinal axis of the wedge and orientated so as to present a hollow, this face having a multitude of small projections.

These characteristics support and promote the excellent performance of the clamp on the cable.

Preferably a gap is made in the body and thewedge has a flexible outwardly extending finger capable of being engaged in the gap in the body in the position when the suspension cable is clamped.

This arrangement prevents any accidental release of the wedge out of the body of the clamp. It should be noted that, if for any reason whatsoever, it should be necessary to remove the clamp, then it is sufficient to slide the locking finger out, extremely simply, before removing the wedge.

Preferably the suspension cable has a core made of glass fibres and a sheath made of flexible synthetic material.

An ernbodiment of the present invention will now be described by way of example only with reference to the accompanying drawings of means for use in the suspension of a power line giving an electrical power supply to vehicles, and in which: Figure 1 is a perspective view of a clamp forming part of said means before fitment; Figures 2 and 3 are respectively plan and perspective views of said means; Figure 4 is a side view of a clamp; and Figure 5 is a section along line 5-5 of Fig.

4.

The means of the invention comprises a clamp 2 and a cable 1 2.

Clamp 2, shown in the drawings, is made from synthetic material and has two main parts, namely a body 3 and a wedge 4 moulded simultaneously and connected to each other permanently by a strand 5.

Body 3 is elongated in shape and on its external face has stiffening ribs 6. Inside body 3 a longitudinal passage 7 is made with an oblong cross-section, that is to say delimited by two substantially parallel side edges 8 of a length greater than that of the top edge 9 and bottom edge 10.

Top edge 9 is semi-cylindrical in shape with a radius corresponding largely to-the radius of a suspension cable 1 2. Bottom edge 10 is flat. As shown, in particular in Figs. 1 and 4, the two edges, namely top edge 9 and bottom edge 10 of passage 7 are relatively inclined, their spacing differing at the two ends of the body.

One of side edges 8 delimiting passage 7 has a longitudinal opening 1 3 having a width at least equal to the diameter of suspension cable 12.

Wedge 4 has two parallel faces corresponding to side edges 8 of passage 7, and two faces inclined in relation to each other, namely top face 14 and bottom face 15. The angle formed by faces 14 and 1 5 corresponds to that formed by edges 8 and 10 of passage 7 so that in the position where wedge 4 is engaged in passage 7 of body 3, edge 14 of wedge 4 is parallel to edge 9 of passage 7.

If bottom edge 1 5 of the wedge is flat, top edge 14 is in the form of a cylindrical surface having a radius corresponding to the radius of cable 1 2 and having a multitude of small projections 16.

Body 3 of the clamp has, leading from opening 1 3, a notch 1 7 and wedge 4 has, in its corresponding face, a finger 1 8 extending flexibly outwards. When wedge 14 is engaged in passage 7 of body 3, finger 18 projects into the inside of notch 1 7 preventing any accidental release of wedge 4 out of body 3.

The bottom part of body 3 has, in addition, a theaded projecting part 19, intended for the attachment of a power line mounting device 20 in which is engaged the top edge of a line 22 of an overhead power line.

Figs. 2 and 3 are views in the form of diagrams of an example of overhead lines intended for supplying power continuously to an electrical vehicle. Suspension cables 12, which may be made from synthetic fibre sheathed by a flexible protection material, are attached, at the height required by their ends, to supports 23, the connection between each suspension cable 1 2 and power lines 22 being made by assemblies having a clamp 2 and a mounting device 20.

From a practical point of view, one clamp is first of all engaged on suspension cable 12, so as to take up support on it with its top edge 9. If it is a curved installation, the side of body 3 having a maximum cross-section of passage 7 will be located on the inside of the curve. The operator then fits wedge 4, the grip on cable 1 2 by the clamp 2 tightening until the finger 1 8 of the wedge penetrates into notch 1 7 of the body of the clamp.

As the foregoing makes clear, the invention contributes a great improvement in weight, in the number of parts and labour, to the existing technique by providing a clamp of simple design, low cost price and enabling the use of cables made of insulating material with all the advantages inherent in such utilisation. In addition, this clamp requires no supervision, nor any maintenance since neither the actual clamp, nor the suspension cable deteriorates in use.

Obviously the invention is not limited to the sole embodiment of the means described above as an example; on the contrary it embraces any production variants. So it is that for other applications and in particular attachment on cable cord, the clamp could be fitted with other means of connection to a component, such as a lug, thimble or collar.

Claims

1. A suspension means for an elongate member comprising a suspended cable including a protection sheath made of flexible material and a clamp having an elongate body with a longitudinal passage which has an oblong cross-section and is defined by two substantially parallel and vertical edges another edge adapted for support on the cable and an opposite edge inclined relative to said other edge so that the spacing between said two opposite edges differs at their ends, the body having mounting means for a line mounting device, a side opening having a width at least equal to the diameter of the said cable and a wedge connected thereto and having two parallel faces and two faces inclined in relation to each other and forming an angle corresponding to the angle formed by the two opposite edges of the passage in the body, the wedge being intended to be engaged in the body to clamp the cable therein.

2. Means in accordance with claim 1, in which the edge of the passage adapted for support on the cable is semi-cylindrical with a radius corresponding to that of the cable.

3. Means in accordance with claim 1 or claim 2, in which the face of wedge intended to contact the cable is in the form of a cylindrical surface having generatrices orientated along the longitudinal axis of the wedge, orientated so as to present a hollow, this face having a multitude of small projections.

4. Means in accordance with any one of claims 1 to 3 in which the body and wedge of the clamp are made from a moulded material, one strand being provided to permanently connect the wedge to the body.

5. Means in accordance with any one of claims 1 to 4 in which the body has a gap therein and the wedge has a flexible projecting finger capable of being engaged in the gap when the suspension cable is clamped.

6. Means in accordance with any one of claims 1 to 5, in which the suspension cable has a core made of natural synthetic fibres and a flexible protection sheath.

7. Means in accordance with any one of the preceding claims, in which the cable is stretched substantially transversely of a road.

8. Suspension means for an elongate member, 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.