GB2207403A - Tensioning a catenary support device in a tunnel - Google Patents

Abstract

An end of an elementary catenary system (1), comprising a supporting catenary (8) and a contact wire (8) is connected by way of an effort-amplifying device (6) to a cable (4) with a balance-weight (3) suspended thereto. The effort-amplifying device is a pulley-block (6) connected to a support (22) secured to the upper wall of the railways tunnel, above the space left free for vehicle traffic. The cable (4) is guided by deflecting pulleys (26) along the transverse curvature of the tunnel inner wall. The balance weight is a flattened body guided between guides (33) laterally of the traffic space. The new device does not need a local tunnel enlargement. <IMAGE>

Description

A DEVICE FOR MECHANICALLY TENSIONING A CATENARY IN A TUNNEL This invention relates to a device for mechanically tensioning a catenary system in a tunnel, especially a railway tunnel.

A catenary system comprises a supporting catenary and a contact wire suspended from the supporting catenary.

To prevent distortion of the catenary, particularly excessive sag, in response to temperature variations caused either by weather conditions or Joule effects, the catenary system is made of successive elementary catenary systems having a length of e.g. 1 km, which are each tensioned by means of tensioning devices automatically ensuring that the required mechanical tension remains constant.

The end portions of successive elementary catenary systems extend parallel to each other over a certain length in order to ensure continuity of the current supply along the railway track.

The tensioning systems are secured to masts supporting the ends of the elementary catenary systems and comprise balance weights which tension the supporting catenary and contact wire through an effort-amplifying means in order to limit the required value of the balance weigths.

The ratio of the effort amplifying means, e.g.

a pulley block, is usually of 1 : 5.

The balance weights are embodied by a stack of cast-iron weights usually with a mass of 20 to 40 kg. The bottom balance weight has a guide eye which slides on a tube extending along the mast and which helps to reduce unwanted swinging of the balance weights.

Catenary equipment for rail tunnels, where available space is usually restricted, is different ; in particular the catenary support wire is often replaced by tunnel supports fixed directly to the crown of the tunnel and there are difficulties in arranging for tensioning systems.

In tunnels where space is particularly restricted niches may have to be contrieved for the balance weights this is always an expensive operation and in some cases even technologically difficult.

The object of the invention is the provision of a device for mechanically tensioning a catenary system adapted as to its configuration and its assembly procedure sothat the catenary can be tensioned mechanically without civil engineering works and without fouling the structure gauge and the kinematic contour.

According to the invention, there is provided a device for mechanically tensioning a catenary system in a tunnel, comprising a balance-weight guided for vertical displacement laterally of a space left free for vehicle traffic, and a cable connecting the balance-weight to an end of the catenary system by way of an effort-amplifying means connected to a stationary support, wherein the support is secured to the tunnel above said space left free for vehicle traffic in the tunnel, and the device comprises means for guiding the cable along a path substantially following the transverse tunnel curvature between the effortamplifying means and the balance-weight.

- Thus, the end of each elementary catenary system is no longer disposed laterally of the space left free for vehicle traffic, but above said space. Moreover, the cable of the balance-weight substantially follows the tunnel profile between the effort-amplifying means disposed above said space and the balance-weight disposed laterally of said space. Such a tensioning device is very compact and does not need an enlarged tunnel section.

Other features and advantages of the invention will be apparent from the following description of a nonlimitative embodiment.

In the accompanying drawings - Figure 1 is a diagrammatic plan view of the adjacent ends of two successive elementary catenary systems - Figures 2 is a cross-sectional view of a tunnel embodying the invention - Figure 3 is a longitudinal section along III III of figure 2 - Figure 4 is a diagrammatic plan view of the tensioning device.

- Figure 5 is an elevation of the balance weight.

- Figure 6 is an elevation of the balance weight in its guides ; and - Figures 7 and 8 are respectively a front view and a side view of a roller element adapted to be secured to the balance weight for movement in the guides.

As shown diagrammatically in figure 1, a catenary system comprises successive elementary catenary systems 1, 2.

Figure 1 more especially shows that adjacent ends thereof are coextensive for simultaneous engagement by the current take-off of the vehicle, in view of ensuring continuity of the current supply to vehicle.

At each end of each elementary system 1 or 2, a balance weight 3 is connected by a cable 4 (schematically shown as horizontal, but in fact vertical) to an effortamplifying means 6 which is in turn connected to the middlepoint of a rocking arm or registration bar 7. The contact wire 8 is connected to one end of the bar 7, and the supporting catenary 9 is connected to the other end of the bar 7. The bar 7 thus distributes tension from the effort amplifying means to both the supporting catenary and the contact wire.

Figure 2 is a sectional view through a tunnel.

There appears a kinematic contour 11, surrounding the space required for vehicle traffic, and a structure gauge 12, i.e. the profile inside which the tunnel should be free from obstacles.

The structure gauge 12 leaves besides the kinematic contour a free space 13 for walking. There is provided on the other side of the tunnel between the structure gauge 12 and the tunnel wall a technical compartment 15.

The catenary system supporting means comprise, at equal intervals along the tunnel, a pair of arms comprising an upper arm 14 for the supporting catenary 9 and a lower arm 16 for the contact wire 8.

Each pair of an upper arm 14 and a lower arm 16 is secured to the tunnel above the kinematic contour 11 by means of an insulator 17. As is usual, the pair of arms 14, 16 which is at equal distances from both ends of an elementary catenary system may be prevented from pivoting about a vertical axis. The other pairs of arms are allowed to pivot about a vertical axis adjacent insulator 17 for accomodating displacement of the supporting catenary and contact wire due to thermal length-variations. There is also shown the position of a feeder wire 18 for feeding the successive elementary catenary systems and two earth wires 19, 21.

As shown in figure 3, the effort-amplifying means 6 is a pulley-block which is mounted between registration arm 7 and a support 22 secured to the tunnel above the kinematic contour 11 (figure 2).

More specifically, the pulley block has one set of pulleys 23 which is connected to registration arm 7 and one set of pulleys 24 which is connected to support 22, the distance between both sets 23, 24 being variable so as to maintain constant the tension in the elementary catenary system in spite of the length thereof varying due to temperature variations.

The pulleys of the pulley block 6 extend in a substantially horizontal plane. In a manner well-known in the art, cable 4 has an end secured to a mounting piece of one of the pulley sets 23 and 24, and successively surrounds the pulleys of pulley block 6. Then cable 4 extends towards the balance weight 3 which is shown in solid lines in its lowermost position (highest thermal expansion of the elementary catenary system) and in phantom lines in its uppermost position (smallest thermal expansion of the elementary catenary system).

According to an important feature of the invention, between the pulley block 6 and the balance-weight 3, the cable 4 is guided along the transverse curvature of the crown of the tunnel by deflecting pulleys 26 which are supported in forks 27 secured to the tunnel 20. Thus, the cable 4 connects the pulley-block 6 located above the kinematic contour 11 with the balance weight 3 located besides the kinematic contour 11.

Between the pulley block 6 and the balance-weight 3, the cable 4 preferably extends in a plane normal to the tunnel axis 29.

As shown in figure 2, for one of the tensioning devices of two adjacent ends of two successive elementary catenary systems, the path of the balance-weight 3 may extend between the technical compartment 15 and the space left free for the vehicle traffic, as defined laterally by the structure gauge 12 and the kinematic contour 11.

The path of the balance weight 3 of the other tensioning device (not shown) of said two adjacent ends may extend adjacent the other side of the traffic space, beyond the walking space 13, as denoted by a phantom line 31.

As shown in figures 2 and 5 considered together, the balance weight 3 is flattened along a plane substantially parallel to a vertical medial plane 32 (figure 2) of the tunnel.

The balance weight 3 is guided for vertical displacement between two guides 33 (figures 2 and 6) which are spaced apart from eachother along the tunnel axis 29.

Each guide 33 connected to the tunnel wall by spacers 51 (figure 4) is comprised of a H-sectional profiled material having its side flanges extending parallel to medial plane 32 of the tunnel.

A roller device 34 is secured to each narrow vertical face of balance weight 3. Said roller device 34 (refer to figures 6 - 8) comprises a bracket 36 carrying two upwardly spaced rolls 37 having an axis parallel to tunnel axis 29 and one roll 38 provided between rolls 37 with an axis being horizontal and normal to tunnel axis 29. The periphery of the rolls 37, 38 is defined by rubber rings (solid tires) 39.

As shown in figure 6, the roll 38 of each roller device 34 is adapted to roll on the center web of one of the guides 33. The rolls 37 are adapted to engage the inner face of either one of the side flanges of a slide 33.

Referring to figure 5, the balance weight 3- comprises a flat cage made of a frame 41, and of flat side connectors 42 which could be alternatively replaced by a panel.Said cage contains parallelepipedic cast iron blocks of for example 40 kg (lower ones) or 20 kg.

Reinforcing plates 43, 44 (figure 5) are provided on the frame for safe securing of the roller devices 34 and respectively a suspension device 46 provided between the balance-weight 3 and the cable 4 (figure 6).

The operation of the device is as follows The balance weight 3 tensions cable 4 up to a relatively limited force which is transmitted by cable 4 along the tunnel crown to pulley-block 6 which amplifies said force and transmits it to the registration arm 7 which in turn distributes said force equally to the supporting catenary 9 and to the contact wire 8. The device does not need any enlargement of the tunnel. Due to the pulleys of pulley block 6 lying in a horizontal place, the planc requirement in height is reduced to a minimum and moreover the cable 4 extends, as from the pulley block 6, in a direction parallel to the tunnel upper wall surface, said direction being appropriate in view of the desired guidance of the cable along the tunnel transverse curvature.

A specific embodiment of the present invention incorporates the following values: Temperature variation: +lO0C to +60 C Mechanical tension of catenary: 4 500 daN Coefficient of expansion of copper: 1.7 x 10-6 Distance from fixed point to tensioning device: 600 m Step-down ratio: 1 : 5 Block of 4 500/5 = 900 daN Length: 2 m Width: 0.1 m Height: 0.65 m Total vertical movement: 5 x 1.7 x 10-6 x 600 x (60 - 10) = 2.55 m.

Claims (8)

1. A device for mechanically tensioning a catenary system in a tunnel, comprising a balance-weight (3) guided for vertical displacement laterally of a space left free for vehicle traffic (11), and a cable (4) connecting the balance-weight (3) to an end of the catenary system by way of an effort amplifying means (6) connected to a stationary support (22), wherein the support (22) is secured to the tunnel (20) above said space (11) left free for vehicle traffic in the tunnel, and the device comprises means (26, 27) for guiding the cable (4) along a path substiantially following the tunnel transverse profile between the effort amplifying means (6) and the balance-weight (3).

2. A device according to claim 1, wherein the effort amplifying means comprise a pulley-block (6) with pulleys extending in operation in a substantially horizontal plane.

3. A device according to claim 1 or 2, wherein the means for guiding the cable comprise at least one pulley (26) supported by the tunnel (20).

4. A device according to one of claims 1-4 wherein the balance-weight (3) is flattened along a plane substantially parallel to a medial vertical plane (32) of the tunnel.

5. A device according to one of claims 1-4, wherein the balance weight (3) is guided for vertical displacement between two guides (33) spaced apart from eachother along the tunnel axis (29).

6. A device according to claim 5, wherein the guides (33) extend between the space left free for vehicle traffic (11) and a lateral equipment compartment (15) extending all along the tunnel.

7. A device for mechanically tensioning a catenary system in a tunnel substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.

8. Any novel feature or combination of features described herein.