CONNECTOR FOR CATENARY WIRES

This invention relates to the maintenance and repair of railway or railroad catenaries.

Such a catenary comprises at least one electrical conductor wire which is suspended from a supporting structure by a series of spaced flexible elements and is connected to a source of electricity, the wire being positioned for engagement on its underside by electrical contacts carried by pantographs mounted on locomotives or power units of trains travelling along tracks beneath the catenary. The wire is usually formed with opposed longitudinal grooves along its respective sides.

Often sections of the wire become worn and have to be replaced. This is done by cutting out the worn section, inserting a new section of wire in its place and joining the opposite ends of the new section to the respective adjacent ends of the lengths of old wire by means of connectors.

The present invention is particularly concerned with connectors used for this purpose.

The connectors at present available on the market are fitted by clamping or crimping methods. To attain correct installation of a new section of wire it is essential that its ends are connected to the ends of the existing sections in such a way as to minimise discontinuities in the wire and/or sudden steps in the underside of the wire which can arise when the sections are aligned because the existing sections will usually still have a degree of wear on their undersides. This is to avoid violent bumps between the wires and the contacts of pantographs. Such violent bumps cause detachment of the pantograph from the wire, so generating electric arcs that will cause excessive damage to the surfaces of both the pantograph contact and the wire.

Since the development of high speed trains that utilise electric locomotives powered through grooved wires, it is increasingly important to limit any such violent bumps, which would be emphasised by the high speed. Such violent bumps would cause undesirable wear and stress both to the pantograph and to the wire.

Up to now this problem has been solved in two ways:

• 1. Manually levelling off the underside of the new wire section so that it is at the same level and also of the same shape as the undersides of the adjacent ends of the existing wire sections. For this purpose operators would typically use tools such as files, grindstones, abrasive discs, etc. This solution is relatively difficult and time consuming when performed correctly and it depends greatly on the ability of the operator.
• 2. Utilising electrical connectors that allow a manual, mechanical adjustment to one or both of each pair of adjacent ends of the sections thereby aligning the surfaces underneath the ends to form a smooth, continuous transition between worn and new sections. This second solution requires the use of a complex and expensive electrical connector and also requires an operator with skill and care to attain correct alignment at installation.

The object of the invention is to provide a connector for the purpose specified that allows easy and correct joining of the ends of two adjacent wire sections.

According to the invention there is provided a connector for joining together opposed ends of two sections of wire in a catenary which comprises a body adapted for attachment to said ends of the two wire sections so as to join said sections together, wherein the underside of the body is formed to provide a surface which, when the connector is attached to the ends of the two wire sections, extends between the undersides of end portions of the wire sections to provide a continuous transition between said undersides for movement of an electrical contact of a pantograph along the wire.

The surface provided by the connector body may arranged so that at one end thereof it is flush with the underside of the adjacent end portion of one of the wire sections to which the connector is attached, the surface extending from said end at an inclination to the length of the other wire section so that it intersects a plane containing the underside of said other wire section irrespective of the position of said plane relative to a plane containing the underside of said one wire section.

In another arrangement the surface provided by the connector body may comprise two longitudinal sections extending in opposite directions from an intermediate part of the surface each at an inclination to the length of a respective wire section so that it intersects a plane containing the underside of said wire section irrespective of the position of said plane relative to a plane containing the underside of the other wire section.

The idea is that when using the connector to join a new wire section to an old wire section which may be partially worn, in the first described arrangement it is attached to the adjacent ends of the sections with the said end of the surface flush with the underside of the new wire section. Then, because the surface extends from its said end at an inclination to the length of the old wire section it will intersect the plane containing the underside of the old section irrespective of the extent to which the underside has been worn away and hence the distance by which the two planes are spaced from one another. In the second arrangement, when the connector is attached to an old wire section and a new wire section, both longitudinal sections of the surface act in this way. In both cases, therefore, the surface therefore provides a smooth continuous transition for a pantograph contact passing along the wire from one section of the wire to the other. This is achieved without any risk of error by a person installing the connector.

The connector preferably has means for locating two wire sections to be joined together in end-to-end alignment. When designed for use with grooved wires these means are preferably opposed ribs or other projections arranged to engage in the respective grooves at opposite sides of the wire sections. These ribs or other projections or/and adjacent portions of the connector which are arranged to contact the wire sections are preferably knurled or roughened so as to increase the surface area of the connector in contact with the wire sections.

The connector is preferably adapted to be attached to the wire sections by gripping them. Conveniently the connector is formed in two parts arranged to be clamped together with the wire sections between them. The opposed faces of the two parts are preferably formed adjacent one side thereof with interengageable formations, for example a rib and a groove respectively, adapted when the two parts are positioned with wire sections between them and the formations are brought together, to act as a hinge enabling the parts to be closed on to the sections. The connector can therefore be fitted easily, minimising the fitting time. The two parts are preferably clamped to the wire sections by bolts extending through the parts although other suitable forms of fasteners could be used.

The invention will now be described by way of example with reference to the accompanying drawings, in which:-

• FIGURE 1 is a side view showing an old section and a new section of a catenary wire in a position ready for their joining together by a connector,
• FIGURE 2 is a cross section of the new section taken on the line II-II in FIGURE 1,
• FIGURE 3 is a side view of one form of connector embodying the invention showing it attached to the wire sections of FIGURE 1,
• FIGURE 4 is an end view of the connector taken in the direction arrow IV in FIGURE 3,
• FIGURE 5 is a perspective view of the connector corresponding to FIGURE 3 and showing a succession of positions adopted by the electrical contact of a pantograph as it passes beneath the connector,
• FIGURE 6 is a perspective view similar to FIGURE 5 taken from the opposite side,
• FIGURE 7 is a side view of the connector similar to FIGURE 3 and showing cross sectional views at the respective positions of the pantograph contact,
• FIGURE 8 is a side view of another form of the connector embodying the invention showing it connected to the wire sections of FIGURE 1,
• FIGURE 9 is an end view of the connector illustrated in FIGURE 8,
• FIGURE 10 is a perspective view from one side of the connector shown in FIGURE 8, and
• FIGURE 11 is a perspective view from the other side of the connector shown in FIGURE 8.

In the drawings FIGURES 1 and 2 show a new section of wire W1 which is required to be joined to an old section of wire W2 in a railway catenary. The wire is formed at opposite sides thereof with grooves G. It will be noted that the underside U1 of the new wire section W1 is concave in shape whereas the underside U2 of the old section W2 has been partly worn away and is flat.

The two forms of connector for joining the wire sections together which are illustrated in the drawings, each comprises a body formed in two parts 1 and 2. The two parts are made of a copper alloy exhibiting the best compromise between the characteristics of mechanical resistance and electrical conduction. The two parts are clamped to the wire sections to join them together and to provide an electrical connection between them.

The opposed inner faces of the two parts 1 and 2 of the body of the connector are formed adjacent one side thereof with opposed longitudinal ribs 3 shaped to engage snugly in the respective grooves G at opposite sides of the wire sections W1 and W2. These ribs are knurled or roughened so as to increase the surface area of the body in contact with the wire sections thereby improving the electrical and mechanical connection. As shown in FIGURE 4 the inner faces of the two parts of the body are also formed adjacent the opposite side with interengageable formations comprising a concave rib 4 on the part 2 and a complementary groove 5 in the part 1.

In the embodiment of FIGURES 3 to 7 the lower portions of the parts 1,2 adjacent the ribs 3 are of rectangular cross section as seen in FIGURE 4 whereas in the embodiment of FIGURES 8 to 11 these portions are of curved tapering form as shown in FIGURE 9 so that they follow the profile of the wire more closely, this keeping the contact point of a pantograph contact closer to the centre of the wire, which is preferable.

The part 2 of the connector in both embodiments is provided with an eyelet 6 to which is attached one of the flexible elements suspending the wire from the supporting structure of the catenary. Alternatively the eyelet could be provided on the part 1. The eyelet is positioned as close as possible to the centre of gravity.

The procedure for joining together the two wire sections W1 and W2 by the connector of the invention first involves bringing together the opposed ends of the sections as shown in FIGURE 1 and holding them in this position by means of a jig or other temporary device (not shown). The two parts of the connector are then brought together in an open position with the rib 4 engaged in the groove 5. The two parts are then closed on to the butting end portions of the wire sections in the manner of a pair of jaws with the rib and groove formations 4 and 5 acting as a form of hinge. The two parts of the connector are then clamped together by bolts 7 which pass through holes in the two parts and are fitted with nuts 8 or other fasteners at their outer ends, there being a sufficient number of bolts to ensure a strong and effective mechanical and electrical connection between the connector and the wire sections. The two parts can only be connected together in the correct way.

It is evident from the drawings that because the two wire sections W1 and W2 are joined together with their grooves G in alignment, the undersides U1 and U2 of the sections (FIGURE 1) are disposed in parallel planes which are spaced from one another. There is therefore a step S at the junction of the two sections (FIGURE 1) which if an electrical contact of a pantograph were allowed to run over it would cause a violent bump and a temporary break in the electrical contact resulting in arcing.

In order to prevent this happening the connector according to the invention is formed with a surface 20 which is arranged to provide a smooth continuous transition for the electrical contact of a pantograph as it travels beneath the connector from one section to another. Such a contact C is illustrated diagrammatically in FIGURES 5, 6 and 7 and in FIGURES 10 and 11 which show a succession of positions C1 .... C5 assumed by the contact as it passes beneath the connector.

The said surface 20 of the connector comprises two surface portions 9, 10 formed on the respective parts 1,2 of the connector body and disposed, in use, at opposite sides of the wire.

In the embodiment of FIGURES 3 to 7 the surface 20 is arranged so that at the end thereof adjacent the new section of wire W1 it is flush with the underside of that section as shown at position C3 in FIGURE 7. The surface extends from this end at an inclination to the length of the old section of wire W2 so that irrespective of the extent to which this section is worn the surface will intersect the plane containing the underside of the old section. As a result the electrical contact of the pantograph is guided by the surface in a smooth continuous movement from or to (depending upon the direction of travel) a position in contact with the old section W2 to or from its position in contact with the underside of the new section W1.

In the embodiment of FIGURES 8 to 11 the surface 20 comprises two longitudinal sections 20a,20b extending in opposite directions from an intermediate part 20c of the surface. The section 20b extends at an inclination to the length of the new wire section W1 and the section 20a extends at an opposite, similar inclination to the length of the old wire section W2. The two sections 20a,20b therefore intersect the respective planes containing the undersides of the wire sections W2,W1 irrespective of the positions of said undersides relative to the connector. This also produces a smooth continuous movement in both directions of travel of a pantograph contact beneath the joint between the two wire sections. This arrangement enables the connector to be used for joining together two old sections of wire one of which is more worn than the other.

The intermediate part 20c of the surface is located at the junction between the two wire sections, the position being marked on the connector by a vertical line and two opposing arrows to provide an aid to correct alignment of the wire sections and assembly of the connector.

Advantages of the present invention are that the variability of the junction between two wire sections due to the operator are eliminated, assembly of the connector is easy and installation time is therefore minimised resulting in a reduction of the total cost. The connector automatically acts to provide a smooth, transitional, inclined surface between the underside of a worn wire section and the underside of a new wire section or another, less worn old section so avoiding geometrical discontinuities or steps that would otherwise cause excessive violent bumping between pantographs and power supply wires. The invention enables there to be minimisation of the weight and dimensions of the connector, installation time and cost and the degree of operator skill required.