FR3076093A1 - DEVICE FOR GROUNDING A CATENARY COMPRISING SECURED ELECTRICITY CONDUCTING MEANS - Google Patents

Abstract

The invention relates to a pole head (3) for grounding a catenary (2), the pole head (3) comprising: - an armature (31); - Electrically conductive means (32) integral with the armature (31) intended to be brought into electrical contact with the catenary (2); connection means (33) connected to the electrically conductive means (32) and intended to cooperate with an earthing cable, characterized in that the electrically conductive means (32) comprise at least two strands ( 321, 322) of metal braids superimposed on each other.

Description

Device for earthing a catenary comprising secure electrical conductor means

The field of the invention is that of the design and manufacture of railway maintenance equipment. More specifically, the invention relates to a tool allowing the grounding of a catenary.

In the field of railway maintenance, worksites can take place in the immediate vicinity of electrified tracks, and therefore of overhead lines. In the majority of cases, the site is carried out without electrical lockout, that is to say without stopping the supply of electricity to the overhead lines.

In addition to the actual power cut, the procedure for intervention on the site requires that the catenary be earthed. The grounding of the catenary overcomes the risks associated with the induction caused by nearby catenaries and under tension, or by an accidental reactivation of catenaries on site.

To connect a catenary to earth, a connection between the catenary and a rail is established. This catenary earthing operation, via a rail, is carried out using an insulating pole, telescopic if necessary, previously equipped with: - a pole head intended to be suspended on the contact wire of the catenary, and - an electric cable connected to at least one of the two rails of a track.

The pole head and the electric cable make it possible to electrically connect the catenary to one and / or the other of the rails which are themselves earthed. We then speak of equipotentiality of the catenary.

Following this intervention, the site area is then protected against any risk of inadvertent overloading of the overhead line, or any accidental arrival of electric current to the overhead line.

These insulating poles are thus essential elements for the safety of maintenance personnel working on the railway.

Insulating poles are generally simple in design. For example, with reference to the patent document published under the number FR2749439, an insulating pole comprises: - a pole; - a pole head formed by a hook secured to the pole and intended to be suspended on the catenary, the head comprising electrically conductive means intended to come into contact with the catenary, and - an electric cable cooperating with the conductive means of electricity and connected to at least one of the two rails on the other hand.

The electrically conductive means are generally in the form of a metallic braid made up of metallic threads woven together. The braids generally have a width such that they define a kind of ply intended to cover a given width of a catenary.

However, the metallic braids are wearing parts which are degraded by various causes, including bad weather, friction on the catenary or heat from the electric current. The wear of a metal braid can cause poor conduction of electricity and therefore an earth of the catenary of poor quality. This therefore presents a risk to the safety of workers working on the tracks.

In the worst case, wear of the metal braid can lead to its rupture and therefore to the lack of earth of the catenary, which represents an immediate danger for workers, especially if the rupture occurs when the insulating pole is suspended from a catenary.

To ensure good insulation of the catenaries and guarantee the safety of workers working on the tracks, it is therefore necessary to check the condition of the metal braids on a recurring basis and to replace them if necessary.

However, light wear is not always detectable during verification operations and an insulating stick can be used when the metal braid should be replaced. If the metal braid such an insulating pole were to break during maintenance operations, the earthing of the catenary would no longer be ensured and the workers would be in danger. The object of the invention is in particular to overcome the drawbacks of the prior art.

More specifically, the invention aims to provide a pole head comprising a metal braid whose wear control is simplified. The invention also aims to propose a pole head guaranteeing the earthing of a catenary in the event of failure of the metal braid. The invention also aims to provide a pole head that is simple in design and manufacture.

These objectives, as well as others which will appear subsequently, are achieved thanks to the invention which relates to a pole head for the grounding of a catenary, the pole head comprising: - a frame; - Electrically conductive means secured to the frame intended to be brought into electrical contact with the catenary; - Connection means connected to the electrically conductive means and intended to cooperate with a grounding cable, characterized in that the electrically conductive means comprise at least two strands of metal braids superimposed one on the other.

The superimposition of the strands allows that in the event of one of the strands breaking, another strand can guarantee the earthing of the catenary. In addition, the visibility of one of the strands through another makes it possible to produce a reliable visual wear indicator.

Indeed, in the event of delamination of the first strand, which is in contact with the catenary, holes will appear in the latter so that the second strand is visible through the first.

Visual inspection of strand wear is particularly simple and reliable when the first strand is broken since the two parts of the first strand will be separated from each other so that the second strand is completely visible.

According to a first embodiment, the strands come from the same metallic braid folded back on itself.

Thus, the manufacture of electrically conductive means is simple and rapid.

According to another embodiment, the strands each come from a different metal braid and are electrically coupled by at least one electrically conductive connection.

It is then possible to use strands of different colors to facilitate visual inspection of the wear of the electrically conductive means. It is also possible to use strands made from wires of different materials.

Advantageously, the electrically conductive means are shaped as a hook.

The hook configuration of the electrically conductive means ensures good hold of the pole head in suspension on the catenary.

Preferably, the frame has a general shape of hook having an opening for the introduction of a catenary in the hook. The hook frame increases the suspension strength of the pole head suspended on the catenary.

According to an advantageous embodiment, the frame comprises two rigid flanges between which are mounted the electrically conductive means.

The rigid flanges provide good mechanical strength to the pole head, in particular so that the latter withstands its weight when it is suspended on the catenary.

Advantageously, the connection means form means for pinching the strands together.

The strands are thus in contact with each other by pinching, which promotes electrical continuity and the earthing of the catenary in the event of one of the strands breaking.

Preferably, the pole head comprises a lock mounted mobile on the frame between: - a first position in which the lock closes the opening to create an enclosed space intended to receive a catenary, and - a second position in which the lock is moved away from the opening to allow insertion or extraction of the catenary in or out of the hook.

The pole head can thus be suspended from the catenary without risk of detachment by vibrations for example. In other words, we make sure that the pole head will not unintentionally unhook.

According to an advantageous embodiment, at least one of the lock and of the frame carries a scraper intended to rub on the catenary.

When placing the pole head on the catenary, the scraper ensures friction on the catenary, which has the effect of removing an oxide layer present on the catenary in order to facilitate the passage of the electric current from the catenary to electrically conductive means. The removal of the oxide layer is an important step for the equipotential bonding of the catenary, that is to say the earthing of the catenary. The invention also relates to a device for grounding a catenary, comprising: - a pole head according to one of the preceding claims, and - a pole for handling the pole head. Other characteristics and advantages of the invention will appear more clearly on reading the following description of a preferred embodiment of the invention, given by way of illustrative and nonlimiting example, and of the appended drawings among which: - Figure 1 is a perspective view of a device for grounding a catenary, according to the invention; - Figure 2 is a side view of a pole head of the device according to the invention; - Figure 3 is a schematic view of a metal braid of the pole head of the device according to the invention, according to a first embodiment, - Figure 4 is a schematic view of a metal braid of the pole head of the device according to the invention, according to a second embodiment.

FIG. 1 illustrates a device 1 for grounding a catenary 2, according to the invention.

The device 1 comprises: - a pole head 3; - a handling pole 4, and - a cable 5 connected to the ground.

The pole head 3, illustrated in FIG. 3 and in cross section in FIG. 4, comprises: - a frame 31 intended to be suspended on a catenary 2; - electrically conductive means 32; - connection means 33; - A lock 34, and - a tip 35 intended to cooperate with the handling pole 4. The frame 31 is rigid, has a general hook shape and comprises two puddles 311, in the shape of a hook, one connected to the 'other by a plate 312. More specifically, the flanges 311 are secured to the plate 312 and held parallel to each other by means of a hook-shaped lattice 313 to which the flanges 311 are fixed by screwing.

The trellis 313 can be made of a metallic material or of a plastic material making it possible to reduce the weight of the pole head 3.

The plate 312 has a barrel 3121 extending opposite the trellis 313.

Referring to Figure 3, the hook shape of the frame 31 has a first end 314 and a second end 315 which define between them a passage 316 through which the catenary 2 is introduced into the hook shape.

The first end 314 is for example a lower end at the level of which the flanges 311 are connected by the plate 312 and the second end 315 is for example an upper end at the level of which the flanges 311 are connected by a metal flange 317.

Furthermore, the metal rim 317 carries a scraper 318 intended to scrape the catenary 2 as will be explained below.

The scraper 318 provides friction on the catenary 2, which has the effect of removing an oxide layer present on the catenary 2 in order to facilitate the passage of the electric current from the catenary 2 to the electrically conductive means 32. The removal of the oxide layer is an important step for the equipotentiality of the catenary 2, that is to say the grounding of the catenary 2.

Each flange 311 has, between the first end 314 and the second end 315, an edge 3111 defining the internal shape of the hook.

The electrically conductive means 32 take the form of a metal braid intended to come into contact with the catenary 2.

The metal braid is made up of at least two strands, one on top of the other.

As shown in FIG. 2, the metal braid comprises three superimposed strands, namely an external strand 321 intended for future contact with the catenary 2, a median strand 322 and an internal strand 323 situated opposite the trellis 313.

According to a first embodiment schematically illustrated in FIG. 3, the electrically conductive means 32 are formed by strands 321, 322, 323 which come from the same metallic braid folded back on itself.

According to a second embodiment schematically illustrated in FIG. 4, the electrically conductive means 32 are formed by strands 321, 322, 323 which each come from a different metallic braid and are electrically coupled by at least one electrically conductive connection. In this case, the electrically conductive connection is formed by the connection means 33 in which one of the ends of each of the arms 321, 322, 323 is joined to the others. The other end of the strands is joined to the others at the metal flange 317.

As illustrated in the figures, the strands 321, 322, 323 are identical, that is to say made from thread of identical material, woven in the same way.

However, each strand 321, 322, 323 could have different characteristics from the others.

For example, the strands 321, 322, 323 could each be of a different color or woven from a thread of different material.

The metal braid is shaped into a hook so as to follow the shape of the flanges 311 of the frame 31 and keep this shape once mounted on the frame 31.

The electrically conductive means 32 are secured, at their first end, to the metal rim 317, and, at their second end, to the connection means 33.

Furthermore, the electrically conductive means 32 are for example fixed to the metal rim 317 by bolting as shown in Figures 3 and 4, or by welding, interlocking or crimping as the metal rim 317.

The connection means 3 form means for pinching the strands 321, 322, 323 therebetween.

According to the present embodiment, the connection means 33, visible in FIG. 2, comprise a first plate 331 and a second plate 332 intended to clamp between them the strands of the metal braid, as is schematically illustrated in FIGS. 3 and 4.

Thus, the connection means 33 form an electrically conductive connection of the strands 321, 322, 232 between them.

The first plate 331 is provided with a plug 333 in which is housed the cable 5 connected to the ground. The cable 5 can then have, for this purpose, a connection lug. The electricity of the catenary 2 then passes through the electrically conductive means 32 then the connection means 33 and finally by the cable 5 which is connected to the ground.

In addition, the first plate 331 is secured to the plate 312 and forms a spacer which participates in the parallel maintenance of the flanges 311 between them.

As shown in Figures 2 and 8, the latch 34 is an arc-shaped part rotatably mounted on one of the flanges 311 of the frame 31, between: - a first position in which the latch 34 closes the passage 316, and - a second position in which the latch 34 is spaced from the passage 316.

The first position of the lock 34 is illustrated in FIG. 1, and the second position of the lock 34 is illustrated in FIG. 2.

On a first face 341, turned towards the outside of the frame 31, the latch 34 carries a scraper 342 intended to scrape the catenary 2 as will be explained below.

The scraper 342 provides friction on the catenary 2, which has the effect of removing an oxide layer present on the catenary 2 in order to facilitate the passage of the electric current from the catenary 2 to the electrically conductive means 32. The removal of the oxide layer is an important step for the equipotentiality of the catenary 2, that is to say the grounding of the catenary 2.

The first face 341 also has a cutout 343 intended to receive a part of the metal rim 317 when the lock is in its first position.

A return element (not visible) is secured to the flange 311 on which the lock 34 is rotatably mounted, this return element being intended to cooperate with the lock 34 to push it back to its first position in which it closes the passage 316. The return element is for example a turn which exerts a force to push the cutout 343 towards the metal rim 317.

This return element makes it possible in particular to secure the pole head 3, in particular by keeping it suspended from a catenary 2 so that vibrations or the wind cannot make it fall from the catenary 2.

Ad hoc control means are coupled to the latch 34 to move it from its first position to its second position. By way of nonlimiting example, the ad hoc means are an actuator (not visible in the figures) coupled in rotation with the end piece 35 in which the handling pole 4 is housed. Thus, by pivoting the handling pole 4, the end piece 35 is rotated and transmits this movement to the actuator which acts on the latch 34 to move it into its second position.

In a variant not shown, the ad hoc control means could be a cord coupled to the latch 34. By exerting a pulling force on the cord, the latch 34 would be rotated to reach its second position. The end piece 35 is in the form of a hollow cylindrical piece of circular section, mounted for rotation on the frame 31. The end piece 35 extends from the plate 312, in a direction opposite to the trellis 313.

The manipulation pole 4 comprises a core 41 and a sleeve 42 mounted at one end of the core 41.

The sleeve 42 can be riveted, screwed, welded or glued to the core 41 for example.

In use, the verification of the operating state of the electrically conductive means 32 can be carried out visually, quickly.

Indeed, in the event of abnormal wear or progressive wear linked for example to the friction of the catenary 2 on the metal braid, the outer strand 321 which comes into contact with the catenary 2 will present delamination which will be easily visible. This is particularly true if each strand 321, 322, 323 has a different color since the color of the intermediate strand 322 will be visible through the outer strand 321.

Under normal conditions of use of the device 1, the technician positions the pole head 3 suspended on the catenary 2 from the level of the rails, that is to say a few meters below the catenary 2.

From its position, the delamination of the outer strand 321 will be easily visible since the intermediate strand 322 will appear through the outer strand 321. The delamination may be all the more easily visible if each strand 321, 322, 323 has a different color, since a task of a different color will appear on the strand 321,322 concerned in the event of delamination. It should be noted that the intensity of the color stain will increase as the delamination of them.

However, if a repair is not possible or if no verification is made, the use of the pole head 3 is still possible, even if there is a risk of breakage of one of the strands 321,322, 323.

However, the superposition of the strands 321, 322, 323, offers a major security in that if the outer strand 321 were to break, the earthing of the catenary 2 would be guaranteed by the present of the intermediate strand 322 which could then come in contact with the catenary 2.

The superimposition of the strands 321, 322, 323 thus provides a visual indicator showing the state of wear of the metallic braid of the electrically conductive means 32.

Furthermore, the presence of the scrapers 318, 342 ensures good electrical conduction of the electrically conductive means 32. In fact, when the technician positions the pole head 3 on the catenary 2, he must pull down on the head of pole 3 so that the lock 34 and the metal rim 317 come into contact with the catenary. By accentuating this pulling movement, the lock 34 passes into its second position so as to free the passage 316. The catenary then rubs against the scraper 342 of the lock 34 then against the scraper 318 of the metal flange 317 to come into contact with the braid metallic. By this friction, the oxide layer present on the catenary 2 is removed allowing to facilitate the electrical conduction between the catenary 2 and the electrically conductive means.

Claims (10)

1. pole head (3) for the grounding of a catenary (2), the pole head (3) comprising: - a frame (31); - Electrically conductive means (32) integral with the frame (31) intended to be brought into electrical contact with the catenary (2); - connection means (33) connected to the electrically conductive means (32) and intended to cooperate with a grounding cable (5), characterized in that the electrically conductive means (32) comprise at least two strands (321, 322) of metal braids superimposed on each other. 2. pole head (3) according to claim 1, characterized in that the strands (321,32) come from the same metal braid folded back on itself. 3. pole head (3) according to claim 1, characterized in that the strands (321,322) are each from a different metal braid and are electrically coupled by at least one electrically conductive connection. 4. pole head (3) according to any one of the preceding claims, characterized in that the electrically conductive means (32) are shaped as a hook. 5. pole head (3) according to any one of the preceding claims, characterized in that the frame (31) has a general shape of hook having an opening (316) for the introduction of a catenary (2) in the hook. 6. pole head (3) according to any one of the preceding claims, characterized in that the frame (31) comprises two rigid flanges (311) between which are mounted the electrically conductive means (32). 7. pole head (3) according to any one of the preceding claims, characterized in that the connection means (33) form means for pinching the strands (321,322) therebetween. 8. pole head (3) according to the preceding claim, characterized in that it comprises a latch (34) movably mounted on the frame (31) between: - a first position in which the latch (34) closes the opening (316) to create an enclosed space intended to receive a catenary (2), and - a second position in which the lock is moved away from the opening (316) to allow the insertion or the extraction of the catenary (2 ) in or out of the hook. 9. pole head (3) according to the preceding claim, characterized in that at least one of the latch (34) and the frame (31) carries a scraper (342, 318) intended to rub on the catenary ( 2). 10. Device (1) for grounding a catenary (2), comprising: - a pole head (3) according to one of the preceding claims, and - a pole (4) for handling the head pole (3).