FR3140818A1 - Section insulator for railway catenary lines - Google Patents

Abstract

Section insulator for railway catenary lines Section insulator (100) for interconnecting a first section (2) and a second section (4) of a contact wire of a catenary line, comprising: - first and second connection means ( 20, 30) for fixing an end part (3) of said first section and an end part (5) of said second section; - two side pads (6, 7) fixed to the first connection means; - two side pads (8, 9) fixed to the second connection means; - a connection rod (40) whose ends are connected to the first and second connection means, the connection rod having a central part capable of coming into contact with a pantograph; - a reinforcing rod (50) whose ends are connected to the first and second connection means in a higher position relative to the connection rod. Figure 1

Description

Section insulator for railway catenary lines

The present invention relates to a section insulator for railway catenary lines.

As is known, section insulators are devices interposed between two sections of the contact wire of a catenary line which are powered independently of each other, and which connect them mechanically.

In particular, section insulators are designed to electrically separate the two sections of the contact wire which are independently energized, while at the same time allowing smooth passage of the pantographs of transiting railway vehicles.

Although known section insulators are quite effective, they still have some aspects that need improvement, particularly regarding their ability to resist deflection and bending forces when the contact wire is preloaded during operations.

In fact, in the event of deviation and bending, the quality of operational interaction with the pantographs of transiting railway vehicles may deteriorate.

It is clear that this aspect is even more important for catenary lines with high operating voltages, for example for high-speed railway applications. In fact, in these applications the creepage distance to be guaranteed is longer and, consequently, the total length of the section insulators, and in particular of their insulating parts, can become significant.

The main objective of the present invention is to solve these problems and, in particular, to provide a section insulator which, while allowing its application at high operating voltages, has improved performance in terms of resistance to bending and deflection forces and allows smooth transitions of the pantographs of moving railway vehicles.

This aim is achieved by means of a section insulator which is suitable for being interposed between and for mechanically interconnecting a first section and a second section of a contact wire of a railway catenary line, the section insulator comprising at least:

- first connection means adapted to fix an end part of said first section of the contact wire;

- second connection means adapted to fix an end part of said second section of the contact wire;

- first and second side pads which are mechanically attached to the first connection means and extend toward the second section of the contact wire along opposite sides of and away from said end portion of said first section of the contact wire;

- a third and a fourth side pads which are mechanically fixed to the second connection means and which extend towards the first section of the contact wire, along the opposite sides of said end portion of the second section of the contact wire and at a distance therefrom; characterized in that it further comprises at least:

- a first connecting rod made of electrically insulating material, a first end of which is connected to the first connecting means and a second opposite end connected to the second connecting means, wherein the first connecting rod is arranged to have at least one central portion capable of coming into surface contact with a pantograph of a railway vehicle in transit; and

- a reinforcing rod made of electrically insulating material, a first end of which is connected to the first connection means and the second opposite end of which is connected to the second connection means, in a higher position relative to the first connection rod.

Other features and advantages will become apparent upon reading the description of certain preferred, but non-exclusive, embodiment examples of a section insulator according to the present invention, illustrated solely as non-limiting examples with the attached drawings, in which:

There is a perspective view showing an embodiment of a section insulator according to the invention;

There is a side view of the section insulator of the ;

There is a view showing in more detail the first and second connection means of the section insulator according to the invention;

There is a view showing in more detail two connecting rods and a reinforcing rod of the section insulator according to the invention.

It should be noted that in the following detailed description, components which are identical or similar, whether structurally and/or functionally, have the same reference numerals, whether or not they are shown in different embodiments of the present invention; it should also be noted that in order to clearly and concisely describe the present invention, the drawings are not necessarily to scale and certain features of the invention may be shown somewhat schematically.

Furthermore, where the term “adapted” or “arranged” or “configured” or “formed”, is used herein in reference to any component as a whole, or any part of a component, or a combination of components, it shall be understood to mean and encompass accordingly either the structure, and/or configuration and/or shape and/or positioning of the relevant component or part thereof, or combinations, to which such term refers.

Furthermore, when the terms “approximately”, “substantially” or “substantially” are used herein, they should be understood to encompass an actual variation of plus or minus 5% from a stated reference value, axis or position, and when the terms “transverse” or “transversely” are used herein, they should be understood to encompass a direction not parallel to the reference part(s) or direction(s)/axis(es) to which they refer, and perpendicularity should be considered a specific case of transverse direction.

Finally, in the description and claims that follow, the numerical ordinals first, second, third etc., will be used only for the clarity of the description and should in no case be understood as limiting for any reason whatsoever; in particular, the indication of a component designated for example as the "third..." does not necessarily imply the presence or the strict necessity of the preceding components "first" or "second" in each embodiment, unless this presence is clearly evident for the proper functioning of the section insulator in question, nor that the order must be that described in the embodiment(s) illustrated by way of example.

There shows an exemplary embodiment of a section insulator according to the invention, designated by the overall reference number 100, which is installed along a railway catenary, a part of which is designated by the reference number 10.

According to well-known solutions and therefore not described here in detail, the catenary line 10 comprises an upper wire 1, generally indicated as carrier cable 1, and at least one lower or contact wire which is designed to come into contact with the pantographs of the railway vehicles in transit, in which the two wires 1 and 2 extend along a longitudinal direction indicated in the by the capital letter Z, that is, the direction of extension of the catenary line 10.

As illustrated, the contact wire comprises a first section 2 and a second section 4 which are spaced apart from each other and extend, substantially aligned with each other, along the Z direction.

The section insulator 100 according to the invention, once installed along the catenary line 10, is interposed between and mechanically connects the first and second sections 2 and 4 while electrically insulating them from each other, and comprises at least:

- first connection means, indicated in Figures 1 and 3 by the overall reference number 20, which are adapted to fix thereto an end portion 3 of the first section 2 of the contact wire;

- second connection means, indicated in Figures 1 and 3 by the overall reference number 30, which are adapted to fix thereto an end portion 5 of the second section 4 of the contact wire;

- a first side skate 6, a second side skate 7, a third side skate 8 and a fourth side skate 9.

In particular, as will be described in more detail hereinafter, the first side pad 6 and the second side pad 7 are mechanically attached to the first connection means 20 and extend, towards the second section 4 of the contact wire, along opposite sides and at a distance from the end portion 3 of the first section 2 of the contact wire.

In turn, in the manner to be described in more detail hereinafter, the third side pad 8 and a fourth side pad 9 are mechanically attached to the second connection means 30 and extend, towards the first section 2 of the contact wire, along opposite sides and away from the end portion 5 of the second section 4 of the contact wire.

The first, second, third and fourth pads 6, 7, 8 and 9 are made, for example, of an electrically conductive material and are intended to ensure continuity of current collection during the passage of the pantographs.

The shape of each of the side pads 6, 7, 8 and 9 is known per se or, in any case, easily accessible to those skilled in the art and is therefore not described in detail in this document.

In practical terms, the section insulator 100 further comprises at least:

- a first connecting rod 40 made of electrically insulating material and which has a first end 42 connected to the first connecting means 20, and a second opposite end 44 connected to the second connecting means 30, in which the first connecting rod 40 is arranged to have at least one central portion 45 capable of coming into surface contact with a pantograph of a railway vehicle in transit (not shown in the figures); and

- a reinforcing rod 50 made of electrically insulating material, a first end 52 of which is connected to the first connection means 20 and a second opposite end 54 of which is connected to said second connection means 30.

Relative to a vertical direction transverse to the longitudinal direction Z, indicated in the by the arrow Y, the reinforcing rod 50 is connected to the first and second connection means 20 and 30 so as to be placed in a higher position relative to the first connection rod 40.

For example, as illustrated in the , the reinforcing rod 50 has a quadrangular or square section and can be made of any suitable material, such as ETO glass, or fiberglass in general, and its ends 52 and 54 are provided with through holes 53.

According to a possible embodiment, the first connecting rod 40 is connected to the first and second connecting means 20, 30 such that one of its lower surfaces, capable of coming into surface contact with a pantograph of a railway vehicle in transit , is located in the same virtual plane on which there is a respective lower surface of one or more, preferably each of the first, second, third and fourth pads 6, 7, 8 and 9.

This virtual plan is represented schematically in the by the dotted line AA and is a plane substantially perpendicular to the vertical direction Y.

In practice, the lower surface of the first connecting rod 40, indicated in Figures 2 and 4 by the reference number 45A, is aligned, in the virtual plane A-A, with at least one of the respective lower surfaces 6A, 7A, 8A and 9A of the corresponding first, second, third and fourth pads 6, 7, 8 and 9, preferably with all of these lower surfaces.

In this way, this inner surface 45A, which is oriented towards the ground, forms a sliding surface against which the pantographs of the railway vehicles in transit can slide, thus contributing, together with the side shoes 6, 7, 8, 9, to the smooth passage of the railway vehicles in transit.

In one possible embodiment, the first and second ends 42, 44 of the first connecting rod 40 are configured to be connected to the first and second connecting means 20, 30, respectively, in a plurality of connecting positions which are rotatable, relative to a longitudinal axis Z' of the first connecting rod 40 itself, each by a predefined angle relative to a previous connecting position.

When the section insulator 100 is installed, this longitudinal axis Z’ is substantially parallel to the longitudinal extension Z of the catenary line 10.

In particular, as illustrated in the , the first and second ends 42 and 44 have a substantially quadrangular or square cross-section and are provided with at least two through holes 43 and 45.

In the example illustrated in the , two through holes 43 and two through holes 45 are provided.

Through holes 43 and 45 allow the insertion of fixing means, for example bolts indicated in the by reference number 12, for fixing the ends 42 and 44 to the respective first and second connection means 20 and 30, for example according to four different connection positions, where each connection position rotates, around the Z' axis, by approximately 90° relative to the previous connection position.

In this way, in each position, the first connecting rod 40 always has a lower surface 45A which is exposed and able to come into superficial contact with the pantographs of the vehicles in transit.

Once the currently used surface 45A has reached a certain wear threshold due to the passage of the pantographs, the first connecting rod 40 can be detached from the first and second connecting means 20 and 30, it can be rotated 90° around the Z' axis into a new position, then reattached to the first and second connecting means 20 and 30, so that a new lower surface 45A is exposed to the pantographs and is able to come into surface contact with them.

In this way, the first contact rod 40 has for example four contact surfaces which can alternately and successively form the lower surface 45A adapted to come into contact with the pantographs.

In one possible embodiment, as illustrated in the , the portion or at least a portion of the first connecting rod 40 which extends between the first and second ends 42 and 44, comprises a core 40A made of a first electrically insulating material, for example fiberglass; furthermore, at least a portion of the core 40A is covered with an outer sacrificial envelope 40B made of a second electrically insulating material, for example different from the first electrically insulating material, for example PTFE.

These parts may have, for example, a circular cross-section.

The total thickness of the outer shell (or part thereof) of the first connecting rod 40 may constitute the wear threshold, i.e. when, for example, the outer shell of the lower surface exposed to the pantograph is completely worn, leaving the core exposed, the first connecting rod 40 must be rotated.

This rotation of the first connecting rod 40 can also be planned according to a predefined maintenance program.

Usefully, in one embodiment according to the invention, the section insulator 100 comprises a second connecting rod 60, made of electrically insulating material, which is positioned at a distance from and substantially parallel to the first connecting rod 40 and which has a first end 62 connected to the first connecting means 20 and an opposite second end 64 connected to the second connecting means 30.

The second connecting rod 60, which is for example substantially identical to the first connecting rod 40, comprises at least one part 65 capable of coming into surface contact with the pantographs of the railway vehicles in transit.

According to a possible embodiment, the second connecting rod 60 is connected to the first and second connecting means 20, 30 such that one of its lower surfaces, capable of coming into surface contact with a pantograph of a railway vehicle in transit , is located in the same virtual plane AA on which there is located a respective lower surface of one or more, preferably each of the first connecting rod 40, of the first, second, third and fourth pads 6, 7, 8 and 9.

In practice, the lower surface of the second connecting rod 60, indicated in by the reference number 65A, is aligned, in the virtual plane AA, with at least one of the respective lower surfaces 45A, 6A, 7A, 8A and 9A, preferably with all of them, of the corresponding first connecting rod 40, and of the first, second, third and fourth pads 6, 7, 8 and 9.

In this way, the inner surface 65A, which is oriented towards the ground, forms a sliding surface against which the pantographs of the railway vehicles in transit can slide, thus contributing, together with the first connecting rod 45 and the side shoes 6, 7, 8, 9, to the smooth passage of these railway vehicles in transit.

In one possible embodiment, the first and second ends 62, 64 of the second connecting rod 60 are configured to be connected to the first and second connecting means 20, 30, respectively, in a plurality of connecting positions which are rotatable, relative to a longitudinal axis Z” of the second connecting rod 60 itself, each by a predefined angle relative to a previous connecting position.

When the section insulator 100 is installed, this longitudinal axis Z” is substantially parallel to the longitudinal extension Z of the catenary line 10 and to the axis Z’ of the first connection rod 40.

In particular, as illustrated in the , the first and second ends 62 and 64 have a substantially quadrangular or square cross-section and are provided with at least two through holes 63 and 65.

In the example shown in the , two through holes 63 and two through holes 65 are provided.

Through holes 63 and 65 allow the insertion of fixing means, for example bolts indicated in by reference number 13, for fixing the ends 62 and 64 to the respective first and second connection means 20 and 30, for example in four different positions, each position being rotated, around the Z'' axis, by approximately 90° relative to the previous position.

In this way, in each position, the second connecting rod 60 always has a lower surface 65A exposed and able to come into superficial contact with the pantographs of the vehicles in transit.

When the used surface 65A has reached a certain wear threshold due to the passage of the pantographs, the second connecting rod 60 can be detached from the first and second connecting means 20 and 30, it can be rotated 90° into a new position, then fixed again to the first and second connecting means 20 and 30, so that a new lower surface 65A is exposed and able to come into surface contact with the pantographs.

In this way, the second contact rod 60 has for example four surfaces which can form the lower surface 65A capable of coming into contact with the pantographs.

In one possible embodiment, as illustrated in , the portion or at least a portion of the second connecting rod 60 which extends between the first and second ends 62 and 64 comprises a core 60A made of a first electrically insulating material; furthermore, at least a portion of the core 60A is covered with an outer sacrificial envelope 60B made of a second electrically insulating material, for example different from the first electrically insulating material, for example PTFE.

These parts may have, for example, a circular cross-section.

The total thickness of the outer shell, or a portion thereof, of the second connecting rod 60 may constitute the wear threshold, i.e. when, for example, the outer shell of the current lower surface 65A exposed to the pantograph is completely worn, leaving the core 60A exposed, the second connecting rod 60 must be rotated and fixed in a new position.

This rotation of the second connecting rod 60 can also be appropriately planned according to a predefined maintenance schedule.

In the illustrated exemplary embodiment, the reinforcing rod 50 extends along a longitudinal axis Z”’, substantially parallel to the axes Z’ and Z” of the first and second connecting rods 40 and 60, and is positioned between the first and second connecting rods 40 and 60 and substantially equidistant therefrom, in a higher position when viewed along the vertical direction Y.

In practice, while the first and second connecting rods 40 and 60 contribute to the smooth transition of the pantographs from one section of the contact wire to the adjacent section along the extension Z of the catenary line and provide the necessary electrical insulation, the reinforcing rod 50 contributes mainly to the structural rigidity, and in particular to the resistance of the section insulator 100 to bending and deflection forces.

There illustrates in more detail a possible embodiment for the first and second means 20 and 30, which are for example substantially identical to each other and, for this reason, indicated by the respective reference numbers in the same .

In the illustrated exemplary embodiment, the first connection means 20 comprise:

• un premier support de montage 22 et un second support de montage 26 qui sont assemblés ensemble.

- a seal 21 mechanically fixed to the end part 3 of the first section 2;

• a first mounting bracket 22 and a second mounting bracket 26 which are assembled together.

In particular, the first mounting bracket 22 has a U-shaped portion whose side arms 22A and 22B are mechanically connected, for example by bolts 14, to the first and second side pads 6, 7.

Two pairs of parallel arms 23A, 23B and 23C, 23D project from the central arm 22C of the U-shaped portion in a direction opposite to that of the side arms 22A and 22B.

Each pair of parallel arms 23A, 23B and 23C, 23D is configured to insert into a respective end 42 and 62 of the first and second connecting rods 40 and 60.

The connection between the rods 40 and 60 and the mounting bracket 22 can be made for example by means of the bolts 12 and 13 which are inserted, depending on the mounting position adopted around the axes Z’ and Z”, in the respective through holes 43 or 45.

The first mounting bracket 22 includes a third pair of parallel arms 23E and 23F which project from the central arm 22C of the U-shaped portion in the same direction as the side arms 22A and 22B.

The second mounting bracket 26, seen from the side, has for example an L-shaped configuration and comprises a first lateral or lower part 26A which is inserted between and connected to the third pair of parallel arms 23E and 23F by means of the bolts 17.

Further, the second mounting bracket 26 has a second side or upper portion 26B that extends along the longitudinal direction Z.

In particular, the upper part 26B comprises two parallel arms.

One end 52 of the reinforcing rod 50 is inserted between one end of the two parallel arms of the upper part 26B and is connected thereto by means of bolts 18 inserted into the through holes 53.

At the opposite end, the two side arms of the upper part 26B are connected by bolts 19 to the joint 21.

Similarly, in the exemplary embodiment illustrated in , the second connection means 30 comprise:

• - deux supports de montage 32 et 36 assemblés l’un à l’autre, ci-après dénommés le troisième support de montage 32, sensiblement identique au premier support de montage 22, et le quatrième support de montage 36, sensiblement identique au deuxième support de montage 26.

- a seal 31 which is mechanically fixed to the end part 5 of the second section 4;

• - two mounting brackets 32 and 36 assembled to each other, hereinafter referred to as the third mounting bracket 32, substantially identical to the first mounting bracket 22, and the fourth mounting bracket 36, substantially identical to the second mounting bracket 26.

In particular, the third mounting bracket 32 has a U-shaped portion whose side arms 32B and 32A are mechanically connected, for example by further bolts 15, to the third and fourth side pads 8, 9.

Two pairs of parallel arms 33A, 33B and 33C, 33D project from the central arm 32C of the U-shaped portion in a direction opposite to that of the side arms 32A and 32B.

Each pair of parallel arms 33A, 33B and 33C, 33D is configured to insert into a respective end 64 and 44 of the first and second connecting rods 40 and 60.

The connection between the rods 40 and 60 and the mounting bracket 32 can be achieved for example by means of other bolts 12, 13 which are inserted, depending on the mounting position adopted around the axes Z’ and Z”, in the respective through holes 63 or 65.

The third mounting bracket 32 includes a third pair of parallel arms 33E and 33F which project from the central arm 32C of the U-shaped portion in the same direction as the side arms 32A and 32B.

The fourth mounting bracket 36, viewed laterally, has for example an L-shaped configuration and comprises a first lateral or lower part 36A which is inserted between and connected to the third pair of parallel arms 33E and 33F by means of further bolts 17.

Further, the fourth mounting bracket 36 has a second side or upper portion 36B that extends along the longitudinal direction Z.

In particular, the upper part 36B comprises two parallel arms.

One end 54 of the reinforcing rod 50 is inserted between one end of the two parallel arms of the upper part 36B and is connected thereto by means of other bolts 18 inserted into the through holes 53.

At the other end, the two side arms of the upper part 36B are connected to the articulation 31 by other bolts 19.

In this way, the section insulator 100 has a lower part formed by the assembled components, namely the four side pads 6, 7, 8 and 9, the first and second connection means 20 and 30, the two connection rods 40 and 60 and the reinforcing rod 50.

Furthermore, as illustrated in the figures, the section insulator 100 according to the invention comprises a carrier cable insulator 70, for example a bell insulator, which is positioned along two adjacent sections of the carrier cable 1 and mechanically connects them; the insulator 70 is per se known or readily available to those skilled in the art and is therefore not described here in detail.

Furthermore, the section insulator 100 comprises two adjustable suspension elements 72 and 74 which are positioned on opposite parts of the insulator 70 and are connected at the upper part of the carrier cable 1, and at a lower part to the first and second connection means 20 and 30.

In particular, as shown in more detail in the , the first and second suspension members 72, 74 pass through the upper portion 26B, 36B of the respective second and fourth mounting brackets 26 and 36 and are connected to the latter by means of bolts 11.

The first and second adjustable suspension members 72 and 74 allow the entire section insulator 100 to be properly adjusted and aligned. They have a configuration per se known or readily available to those skilled in the art and are therefore not described in detail herein.

It is therefore clear from the foregoing description that the section insulator 100 according to the present invention achieves the intended objective since it has a structure which ensures an appropriate creepage distance, offers better resistance to bending and deflection and thus improves the overall quality and efficiency of the dynamic interaction with the pantographs.

These results are achieved thanks to a solution that is easy to manufacture and assemble at a relatively low cost, which can also be applied to railway catenaries operating at higher voltages, for example for high-speed railway lines.

The section insulator 100 thus designed is susceptible to modifications and variations which all fall within the scope of the concept of the invention as defined in particular by the appended claims; for example, depending on the specific application, some of the components, for example the first or second connecting rod or the reinforcing rod or parts thereof may be made of a different material than that previously mentioned, or one of them may have a different configuration provided that it remains adapted to the framework and the functionalities designed for this (these) rod(s) in the context of the present invention.

All details can also be replaced by technically equivalent elements.

Claims (10)

Section insulator (100) capable of being interposed between and mechanically interconnecting a first section (2) and a second section (4) of a contact wire of a railway catenary line (10), the section insulator (100) comprising at least:
- first connection means (20) adapted to fix an end part (3) of said first section (2) of the contact wire;
- second connection means (30) adapted to fix an end part (5) of said second section (4) of the contact wire;
- a first side shoe (6) and a second side shoe (7) which are mechanically fixed to the first connection means (20) and extend towards the second section (4) of the contact wire along opposite sides and at a distance from said end portion (3) of the first section (2) of the contact wire;
- a third side pad (8) and a fourth side pad (9) which are mechanically fixed to the second connection means (30) and extend towards the first section (2) of the contact wire, along opposite sides and at a distance from said end portion (5) of the second section (4) of the contact wire; characterized in that it further comprises at least:
- a first connecting rod (40) made of an electrically insulating material and having a first end (42) connected to the first connecting means (20) and a second opposite end (44) connected to the second connecting means (30), wherein the first connecting rod (40) is arranged to have at least one central portion (45) capable of coming into surface contact with a pantograph of a railway vehicle in transit; and
- a reinforcing rod (50) made of electrically insulating material, a first end (52) of which is connected to the first connection means (20) and a second opposite end (54) of which is connected to the second connection means (30), in a higher position relative to the first connection rod (40). A section insulator (100) according to claim 1, wherein the first connecting rod (40) is connected to the first and second connecting means (20, 30) such that a lower surface (45A) thereof, capable of superficially contacting a pantograph of a railway vehicle in transit, lies in a same virtual plane where a respective lower surface (6A, 7A, 8A, 9A) of one or more of the first, second, third and fourth pads (6, 7, 8, 9) lies. Section insulator (100) according to any one of the preceding claims, wherein the first connecting rod (40) comprises said first and second ends (42, 44) which are configured to be connected to said first and second connecting means (20, 30) in a plurality of connecting positions which are rotatable, relative to a longitudinal axis (Z') of the first connecting rod (40) itself, each by a predefined angle relative to a previous connecting position. A section insulator (100) according to any preceding claim, wherein said first connecting rod (40) comprises a core made of a first electrically insulating material and a cover made of a second electrically insulating material different from the first electrically insulating material. Section insulator (100) according to any one of the preceding claims, comprising a second connecting rod (60), made of electrically insulating material, which is positioned at a distance from the first connecting rod (40) and substantially parallel thereto and which has a first end (62) connected to the first connecting means (20) and a second opposite end (64) connected to the second connecting means (30). A section insulator (100) according to claim 5, wherein the second connecting rod (60) is arranged to have at least one portion (65) capable of coming into surface contact with a pantograph of a railway vehicle in transit. A section insulator (100) according to claim 5, wherein the second connecting rod (60) is connected to the first and second connecting means (20, 30) such that a lower surface (65A) thereof, capable of coming into surface contact with a pantograph of a railway vehicle in transit, is in the same virtual plane where at least one of the lower surfaces (45A, 6A, 7A, 8A, 9A) of the first connecting rod (40) and the first, second, third and fourth side pads (6, 7, 8, 9) are located. Section insulator (100) according to any one of claims 5 to 7, wherein the first and second ends (62, 64) of the second connecting rod (60) are configured to be connected to the first and second connecting means (20, 30) in a plurality of connection positions capable of being rotated, relative to a longitudinal axis (Z”) of the second connecting rod (60) itself, each by a predefined angle relative to a previous connection position. A section insulator (100) according to any one of claims 5 to 8, wherein the second connecting rod (60) comprises a core made of a first electrically insulating material and a cover made of a second electrically insulating material different from the first electrically insulating material. The section insulator (100) of claim 5, wherein the reinforcing rod (50) is positioned between and substantially equal distance from the first and second connecting rods (40, 60).