GB2289377A

GB2289377A - Maintenance and repair of overhead cables using platform carried by helicopter

Info

Publication number: GB2289377A
Application number: GB9508869A
Authority: GB
Inventors: Philippe Ruaux; Jean-Pierre Jouglard
Original assignee: Electricite de France SA
Current assignee: Electricite de France SA
Priority date: 1994-05-13
Filing date: 1995-05-02
Publication date: 1995-11-15
Anticipated expiration: 2015-05-02
Also published as: FR2719952A1; FR2719952B1; GB9508869D0; GB2289377B

Abstract

A platform for suspending from overhead cables 9 comprises a metal structure (20, 26 Figure 4) within which an operator (Figure 7) can be located and two pairs of rollers 12 with wide grooves 14 for locating the structure on the cables 9; the wide grooves allowing location of the structure even if there are wide variations of the distance between the cables (Figures 2A, 2B and 3B). The platform can be used to maintain or repair both overhead electric cables and those used for cable-cars, a helicopter being used to carry the platform into position (Figure 1). <IMAGE>

Description

Helicopter carried nacelle for placing on cables with a variable spacing.

DESCRIPTION Field of the Invention.

The invention relates to the maintenance and repair of overhead cables, such as electric cables of the public electric power transportation and distribution network.

The invention could also apply to the cables of transportation means such as those of cableways and other cabins carried on cables and able to withstand the supplementary weight of a maintenance nacelle. The invention also relates in indirect manner to helicopter transportation.

Prior Art and Set Problem.

Once installed, most overhead cables require numerous maintenance, repair and installation operations. Thus, within the framework of the maintenance and installation programs of the electric power distribution network, ELECTRICITE DE FRANCE must carry out numerous interventions. These include the installation of beacons or spacers for maintaining at a predetermined distance several electric cables and for the replacement of coupling sleeves on conductors in bundle form requiring a human intervention on said cables.

French patent application FR-A-2,675,962, filed by the present applicant, discloses a helicopter carried nacelle or basket making it possible to rapidly intervene on overhead cables in bundle form. This document also describes a fork making it possible to transport and place the nacelle on the cables or on the ground.

The nacelle has a metal structure carrying operators and equipment. On its sides it has fixing hooks to enable a transportation fork, connected to a helicopter, to grip the same. The nacelle can then be suspended on overhead cables by means of two fixing bars having lower notches in which the cables are placed.

Such a nacelle is obviously used on a large number of cables combined in bundle form, but whose spacing is substantially constant. However, as in the case of the British power distribution network, the conductor cables are also used in bundle form, i.e. in the form of two, three or four cables, but with a variable spacing between the cables. Thus, in theory, the aforementioned nacelle is then unusable.

The object of the invention is to obviate this disadvantage by proposing a helicopter carried nacelle positionable at any location on a cable bundle with a variable spacing between the cables.

Summary of the Invention To this end, the main object of the invention is a helicopter carried nacelle constituted by a metal structure for placing on overhead cables and within which can be carried at least one operator. It also relates to means for fixing to two overhead cables.

According to the invention, these fixing means are constituted by two pairs of rollers having a horizontal axis and below which are placed the two overhead cables, each of the rollers having a very wide groove so that the same pair of rollers can be placed on cables having a variable spacing at a random location, no matter what the spacing between them.

The rollers of each pair are preferably installed on a mobile arm pivoting about a horizontal axis parallel to the two sides of the metal structure and which are to be parallel to the overhead cables. This is advantageously completed by a system for opening and closing the arm. It can be constituted by a first pivoting lever, positioned laterally so as to be accessible to an operator seated in the nacelle and connected to a rod mounted in pivoting manner on the arm.

Means for locking in the closed position the arm carrying the rollers can also be used. In this case, they are preferably constituted by a second lever mounted in pivoting manner so as to be actuatable by an operator seated in the nacelle by the first end thereof and having an abutment on its second end preventing the arm from returning to its open position.

In the preferred embodiment of the nacelle, the metal structure defines a compartment within which there is a seat or a means enabling an operator to sit.

Preferably the metal structure of the nacelle defines a compartment within which there is a seat or a means on which an operator can sit. Said seat or means enabling the operator to sit can be a case placed on the floor of the nacelle.

List of drawings.

The invention is described in greater detail hereinafter relative to a non-limitative embodiment and with reference to the attached drawings, wherein show: Fig. 1 the framework of use of the nacelle according to the invention.

Figs. 2A and 2B two different types of overhead cable bundles.

Figs. 3A and 3B, in section, part of the nacelle according to the invention used on bundles of cables having a variable spacing.

Fig. 4 the nacelle according to the invention.

Fig. 5 a detail of a first control lever used in the nacelle according to the invention.

Fig. 6 a constructional detail of a second control lever used in the nacelle according to the invention.

Fig. 7 the nacelle according to the invention and within which is located an operator.

Detailed description of an embodiment of-the invention.

Fig. 1 shows the framework in which the present invention is used, i.e. one or more overhead cable bundles 1 suspended between two pylons 2. The nacelle 3 is brought by helicopter using a fork 4 and a rope 5. The helicopter brings the nacelle or basket 3 with one or more operators in its interior and deposits it on an overhead cable bundle 1 so that the operator or operators are able to perform maintenance, repair or installation operations on said overhead cables 1. Once the nacelle 3 has been deposited on the latter, the helicopter 6 equipped with the rope 5 and the fork 4 can fly away and at the desired time returns for the nacelle 3 and removes it by means of the fork 4 and unloads it on the ground.

Fig. 2A shows a bundle of two overhead cables 1 maintained at a constant distance over their entire length between their two attachment points 7. The spacers 8 are provided for maintaining said predetermined spacing.

However, fig. 2B shows two overhead cables 9 with a variable spacing. The successive spacers 11 11 lln are intended to n maintain them at this variable spacing. This type of overhead cable bundle is used on the British grid.

A nacelle according to the invention 10 is shown in mixed line form level with a spacer 112 maintaining the two overhead cables 9 in a close together position.

Fig. 3A shows the upper part of the nacelle 10 of fig. 2B.

It is mainly possible to see the two rollers 12 mounted so as to rotate about a first horizontal axis 13. These rollers 12 are very wide, as are their respective grooves 14, which extend over virtually the entire width of the roller 12. They are mounted so as to rotate on a shaft 15 by means of flanges 16 extending from each side of the rollers 12.

The nacelle is mounted on a bundle of three cables 9, whereof the two upper cables are placed below two rollers 12, each being located in a groove 14 of one of them. These cables 9 are shown in continuous line form in a position in which they are widely spaced apart. Therefore the two upper cables are almost against the outer edge or flange 17 of the groove 14 of each of the rollers 12. However, these three cables are shown in broken line form in a position where they are relatively close to one another. In this position it is possible to see that the two upper rollers are against the inner edge or flange 18 of the groove 14 of each of the two rollers 12. In the same way, the lower cable is closer to the others, i.e. is raised. These three overhead cables 9 are maintained in their position by spacers 11.

Fig. 3A also shows the upper part 20 of the metal structure of the nacelle. On said upper part 20 is mounted in pivoting manner the arm 15 carrying the rollers 12. This pivoting takes place about a second horizontal spindle or axis 21, perpendicular to the first horizontal spindle or axis 13 and parallel to the two sides of the metal structure of the nacelle to be positioned parallel to the cables 9. A first manipulating arm 22 is integral with the arm 15. The arrow 23 starting from the end of said manipulating arm 22 symbolizes a tensile stress which can be exerted on the latter in order to raise by pivoting the arm 15 and the rollers 12.

In fig. 3B the same upper part 20 of the upper metal structure of the nacelle according to the invention is shown. The arm 15 is still in the closed position and each of the rollers 12 is still placed on a cable 9, themselves in the spaced position as shown in fig. 3A.

The difference between fig. 3A and fig. 3B is that there are four cables 9. Thus, the cable bundle comprises two upper cables and two lower cables interconnected by cross-shaped spacers 111. In the same way in fig. 3B one of the spacers 112 is shown in broken line form and joins the same four cables 9, but in a closed up position. Thus, the two upper cables are placed against the inner flange 18 of the groove 14 of each of the rollers 12.

Fig. 4 shows the nacelle according to the invention. It is possible to see the two arms 15, each carrying a pair of rollers 12, the first arm being in the closed position (horizontal rollers 12) and the second arm in the open position (vertical rollers 12). The large, circular arc arrow 24 symbolizes the opening and closing movements of the arm 15 with respect to the two upper cables 9.

Fig. 4 shows a construction of the metal structure of a nacelle according to the invention. It is also possible to see the upper part 20 of said metal structure, as well as a lower part 26 carrying a floor 25. The metal structure e.g. has a parallelepipedic shape.

A case 27 is shown in fine line form on the floor 25. It is able to contain the embarked equipment (e.g. repair tools) and also enables an operator to sit in the nacelle or basket.

On the sides of the nacelle carrying the arms 15 are fixed two conduits 28 which are inverted downwards and rigidly fixed by means of a fitting 29 to the upper part 20 of the metal structure. They enable the arm 31 of a fork 30, suspended by helicopter carrying, to engage on either side of the nacelle with a view to transporting it to any random location. It is possible to use pins, straps or clip hooks to carry out the locking of the arms 31 of the fork 30 on the nacelle. Once the fork 30 has been put into place by these arms 31 beneath the conduits 28 of the nacelle, the latter can be transported by helicopter, can be placed on a cable bundle 9 and can be fixed above by closing the arms 15, each roller 12 engaging by an upper contact on a cable 9 on which it is supported.

A spring 32 is fixed on the one hand to the end of the manipulating arm 22 and on the other to the upper part 20 of the metal structure. Therefore each of the two arms 15 carrying the rollers 12 tends to remain in its open position. However, by means of a first lever 34 mounted so as to pivot on a rod 33, it is possible to pivot the assembly of the manipulating arm 22 and the arm 15 about their pivot pin 21. It is therefore possible for the arms 15 to be closed by an operator carried in the nacelle. He can therefore fix the same to the two upper cables 9 of the bundle on which the nacelle is to be installed.

A second lever 44 terminated by a lower handle 46 is mounted so as to pivot about a third horizontal spindle 45 with respect to the upper part 20 of the metal structure. The lower handle 46 is accessible from the interior of the nacelle, whilst an upper end 47 has an abutment 48 making it possible to secure the arm 15 in its closed position in a slot 39 of the upper part of the metal structure 20.

In the front of fig. 4, the manipulating arm and the arm 15 are in the closed position. The first actuating lever 34 is raised upwards, because it is mounted in pivoting manner on the metal structure about a fifth horizontal spindle 36. This operating lever 34 is also mounted in pivoting manner by an articulation or joint 37 on the lower end of the rod 33. On the rear part of the nacelle, the first lever 34 is lowered, as is suggested by the small circular arc arrow 38. Therefore the control rod 33 is raised and the arm 15 carrying the rollers 12 is vertical, i.e. in the open position.

Fig. 5 shows in detail the device for actuating the arm 15 carrying the rollers 12. It is shown in thick line form in the closed position and in mixed line form in the open position. The rod 33 is mounted so as to pivot with respect to the arm 15 about a horizontal spindle 35. Therefore an upwards thrust on said rod 33 brings about by its pivoting with respect to the arm 15 about a fourth spindle 35, the pivoting of the arm 15 about the first spindle 21. The fourth spindle 35 pivots about said first spindle 21. The spring 32 has also participated in this movement by pulling on the operating arm 22.

With reference to fig. 6, the arm 15 is in the closed position and the second manipulating lever 44 is vertical, its abutment 48 maintaining the arm 15 in said closed position. Therefore the manipulating handle 46 is forced towards the outside by the operator.

The second manipulating lever is shown in mixed line form in the unlocked position, i.e., in the manner suggested by the first sagging arrow 49, the abutment 48 is freed from the slot 39 and releases the arm 15. However, in the manner suggested by the second circular arc arrow 50, the operator can draw the manipulating handle 46 towards him in order to carry out locking.

A blocking in the closed position of the second manipulating lever 44 can be used. It can also be carried out by a pin 51 penetrating a hole 52 of the metal structure issuing just alongside the lower end of the second manipulating lever 44 to maintain it in the locked position.

Fig. 7 shows an operator seated on the case 27 of the helicopter carried nacelle. The operator can be both transported and can work in said seated position. Thus, in front of his head is located the lower cable 9 of the bundle of three cables. He can therefore carry out any random maintenance or installation operation on one of the three cables located just above him.

The assembly can be completed by a work tablet 52.

In fig. 7 it is also possible to see in mixed line form the first manipulating lever 34 permitting the actuation of the arm 15 carrying rollers 12. A positioning fitting 53 can be located laterally with respect to the nacelle in order to permit the positioning thereof relative to the cable bundle. The second manipulating lever 44 is also shown in its position locking the arm 15.

A helicopter carried nacelle of the type described hereinbefore can be made from an aluminium alloy or a composite and/or insulating material.

Thus, such a helicopter carried nacelle can be positioned and deposited on electric cables in the form of bundles of two, three or four and with a variable spacing between the cables.

Such nacelles can be put into place on all such cables which may or may not be live.

The fact that these rollers 12 are installed so as to pivot with respect to the arm 15 enables the nacelle to move over the entire length of the cables, the spacing between them being variable. The translation energy for the nacelle can be supplied by a towing device installed beforehand on the nacelle. It is therefore possible to cover a complete cable span, where the spacing between the cables can vary between 250 and 500 mm.

The operator has at his disposal all the control, closing and locking manipulations for the nacelle with respect to the cables.

The design of the helicopter carried nacelle enables the operator to be in a working position beneath or between the conductor cables.

Claims

1. Helicopter carried nacelle for placing on overhead cables (9), constituted by a metal structure (20,26) within which can be located at least one operator and comprising means for fixing to two overhead cables (9), characterized in that the fixing means are constituted by two pairs of rollers (12) mounted so as to rotate about a first horizontal spindle (13) and below which are placed two cables (9), each of the rollers (12) having a very wide groove (14), so that the same pair of rollers (12) can be placed on two cables (9) with a variable spacing at any random location and no matter what the spacing thereof.

2. Nacelle according to claim 1, characterized in that the metal structure (20,26) defines a compartment within which is provided a seat or a means (27) enabling an operator to sit.

3. Nacelle according to claim 1, characterized in that the rollers (12) of each pair are mounted on a mobile arm (15), mounted so as to pivot about a second horizontal spindle (21), parallel to the two sides of the metal structure (20,26), which are intended to be parallel to the cables (9).

4. Nacelle according to claim 3, characterized in that it incorporates an opening and closing system for the arms (15).

5. Nacelle according to claim 4, characterized in that it comprises a first lever (34) mounted in pivoting manner and placed laterally so as to be accessible to an operator seated in the nacelle and connected to a rod (33), which is itself installed in pivoting manner on a manipulating arm (22) integral with an arm (15).

6. Nacelle according to claim 3, characterized in that it incorporates means for locking in the closed position the arm (15) on the metal structure (20,26).

7. Nacelle according to claim 6, characterized in that the locking means are constituted by a second lever (44) mounted in pivoting manner so as to be actuated by an operator seated in the nacelle by means of a first end or a handle (46) and having a second end equipped with an abutment (48) preventing the arm (15) from returning to its open position.

8. Nacelle according to claim 1 comprising means for fixing to a carrying element which can be suspended on a helicopter (6), characterized in that said fixing means comprise two horizontal, inverted conduits (28), each placed on one side of the metal structure (20,26) of the nacelle and intended to receive the arms (31) of a fork (30).

9. Nacelle according to claim 2, characterized in that the means enabling an operator to sit is a case (27) placed on the nacelle floor (25).