GB2330241A - Dropper assembly for supporting an overhead electrical supply line for trains - Google Patents

Abstract

A dropper for mechanically and electrically interconnecting an overhead conductor for trains to a support cable has a clamp (14,16) with a pivotally mounted jaw, which enables clamping to a contact conductor (20) or to a support cable (18) having different diameters, each with a respective portion of the jaws. Each clamp is connected to the end of a binder cable (4) via an eyepiece (6,8). Preferably the jaws pivot about a cylindrical portion and clamp with opposed concave surfaces.

Description

DROPPER ASSEMBLY FOR SUPPORTING AN OVERHEAD ELECTRICAL SUPPLY LINE FOR TRAINS This invention relates to a dropper providing a mechanical and electrical interconnection between a support cable and an overhead supply conductor for trains.

A dropper cable is described in international application W096/01747. Dropper assemblies as described in the afore mentioned application comprise a cable crimped proximate opposed ends to a mechanical and electrical connection assembly, a first clamp assembly for clamping to a support cable, and a second clamp assembly for clamping to a conductor. The support cable provides mechanical support of an overhead electrical power supply conductor for trains.

The length of the binding cable interconnecting the support cable to the conductor is adjusted such that the height of the overhead contact conductor is maintained substantially constant above the railway tracks. The dropper also serves to supply electrical power from the support cable to the contact conductor. In view of reducing manufacturing and handling costs and, also, in view of reducing the number of parts to be assembled together, it is known to provide droppers with clamps for the support cable and for the contact conductor that are identical, as disclosed in DE 30 36 045. An important advantage of the assemblies described in the above mentioned patent applications is that the clamp assemblies are loosely attached to the binding cable by means of inter-engaging annular hook and eye portions. During passage of a train, the contact conductor is subject to shock waves that shake the dropper assembly. The annular interengagement of the hook portions decouples the clamp from the binder cable substantially reducing the shaking of the binder cable. In designs where the binder cable is crimped to the clamp, the cable typically breaks due to metal fatigue proximate the crimp connection in light of the forced shaking of the cable and clamp. The decoupled designs as described in WO 96/01747 can withstand many more train passages before rupture. Present two-part clamps with annular hook portions, as described in WO 96/01747 and DE 30 36 045, however are not able to adjust to cables and, in particular support cables with different diameters. Such clamps are provided to clamp support cables of specific dimensions.

There are,however, countries where the size of support cables varies, for example between 9mm and 12morn. It is also desirable to reduce costs, ease of assembly and handling, whilst ensuring reliable and robust interconnection.

It is an object of this invention to provide a dropper assembly that is simple to assemble to support cables and contact conductors and that can adjust to cables of different sizes, whilst being able to withstand many vibration cycles.

Objects of this invention have been achieved by providing the dropper assembly according to claim 1.

Disclosed herein is a dropper assembly for mechanically and electrically interconnecting a support cable to an overhead contact conductor for supplying trains with electrical power, the assembly comprising a binder cable having eye pieces attached at opposed ends of the cable, and a first clamp fixed loosely to one of the eye pieces and a second clamp fixed loosely to the other of the eye pieces, the first clamp for clamping the dropper assembly to the support cable and the second clamp for clamping the dropper assembly to the contact conductor, the first clamp comprising a first member and separate therefrom a second member, wherein the second portion is pivotally mounted to the first portion about a pivot axis proximate a first end of the second portion, a second opposed end of the second portion provided with a clamping jaw, the first portion being provided with a clamping jaw opposed to the second portion clamping jaw, the opposed clamping jaws comprising a first portion for receiving a support cable therein, and a second portion for clamping a contact conductor, the first member having a half hook portion that interengages with a third portion comprising a half hook portion, thereby forming an annular hook engaging in a complementary annular ring of the binder cable eyepiece.

Advantageously, therefore, the pivot mounted clamping jaw enables connection of the clamp to support cables of different diameters, in addition to clamping to a contact conductor whilst enabling many vibration cycles of the contact conductor.

Further advantageous aspects of this invention are described in the claims or will be apparent from the following description and drawings.

An embodiment of this invention will now be described by way of example with reference to the drawings in which; Figure 1 is a view of a dropper assembly clamped to a support cable and a contact conductor; Figure 2 is a view in the direction of arrow 2 of Figure 1; Figure 3 is a view of a clamp fixed to a contact conductor; Figure 4 is a view of a clamp fixed to a small diameter support cable; Figure 5 is a view similar to that of Figure 4 but with a large diameter support cable; Figure 6 is a side view of the clamp of any one of Figures 3-5; Figure 7 is a side view of a first member of the clamp; Figure 8 is a view in the direction of arrow 8 of Figure 7; Figure 9 is a cross-sectional view through lines 9-9 of Figure 7; Figure 10 is a view in the direction of arrow 10 of Figure 7; Figure 11 is a view of a second member of the clamp, the view taken in the direction similar to that of Figure 10; Figure 12 is a side view of a third member of the clamp; Figure 13 is a view in the direction of arrow 13 of Figure 12; and Figure 14 is a view in the direction of arrow 14 of Figure 12.

Referring to the Figures, a dropper assembly 2 comprises a binder cable 4, eye pieces 6,8 securely attached to the cable 4 proximate opposed ends 10,12 of the cable, and clamps 14,16 mounted to either eye piece 6,8 respectively, a first one of the clamps 14 for fixing to a support cable 18, and a second one of the clamps 16 for fixing to a contact conductor 20. The support cable 18 mechanically supports the contact conductor 20, and supplies it with electrical power.

The contact conductor 20 has a contact surface 22 for electrical contact against a contact mechanism of a train that rubs thereagainst. The binding cable 4 is provided at the length required to maintain the contact conductor 20 at a substantially constant height above railway tracks.

The eye pieces 6,8 are identical parts, each comprising a binding cable attachment portion 24, a conducting bridge cable attachment portion 26, and an eye portion 28. The binding cable attachment portion 24 has a bore 30 for receiving the binding cable therein, the portion 24 subsequently being deformed by crimping for secure attachment to the cable 4. Similarly, the bridge cable attachment portion 26 comprises a bore 32 for receiving a conducting bridging cable 34 therein. A side wall of the attachment portion 26 is subsequently deformed by means of a crimped indent 38 for mechanically and electrically attaching the cable 34 to the eye piece. The other end 35 of the bridging cable 34 is crimped in a similar manner to the clamp 14,16 in order to ensure good electrical contact between the clamp and the binding cable. The clamp end 35 is crimped to the clamp 14,16 by means of the indent 39 crimping the cable end within the conductor receiving cavity 40 of the clamp. The eye portion 28 is ring shaped and has a hole 33 for receiving hook portions 42,44 of the clamp 14,16.

Each clamp 14,16 comprises a first member 46, a separate second member 48, and a separate third fixing member 49. The first member 46 comprises the attachment hook 44 and the third member 49 comprises the attachment hook 42, whereby the hooks 42,44 substantially form halves of an annular hook portion. The hooks 42,44 are assembled together in an interlocking arrangement to form a substantially complete annular ring interlocked with the eye portion 28. As best seen in Figures 8 and 13, the hooks 42,44 have locking faces 41,43,respectively,that lie against each other when the hook members are assembled together. Obliqueinterengaging locking shoulders 45,47 are provided on the locking faces in order to lock the hooks together. During assembly, the leading ends of the locking faces 41,43 abut against each other in an interference fit such that the passage of the locking shoulders 45,47 past each other causes the hook portions 42,44 to clip (lock) together. The abutment of the locking faces 41,43 is caused by interengaging projections 37 and recesses 39 on each of the hooks 42,44 that have dovetail shapes (as shown in Figure 14) such that the protrusions are securely held within the cavities. The projections and corresponding recesses 37,39 have slightly tapered outer side surfaces 31 such that the locking faces 41,43 are biased towards each other during insertion of the projections 37 into the recesses 39 in the mounting direction (M), until interference of the locking faces 41,43 and subsequent interengagement of the locking shoulders 45,47. The first member 46 can thus be rapidly assembled to the eye portion 28 by tapping the third member 49 (e.g. with a hammer) into engagement with the first member until the locking shoulders 45,47 interengage.

The second clamping member 48 is mounted pivotly to the first member 46, for rotation substantially about a pivot axis 50 arranged proximate the mounting portions 42,44. The first and second clamping members 46,48 are provided with opposed jaws 52,54 proximate free ends 58 remote from the hook portions 42,44. The jaws 52,54 are provided with first clamping surfaces having concave portions 56,57 in opposed relationship for receiving the support cable 18,18' therebetween. Free ends 58 join the concave portions 56,57 at corners 60 which are second clamping portions designed to be received in corresponding indents 62 of a contact conductor for clamping thereof. With respect to a vertical axis V in the direction of the binding cable 4, the clamping surfaces 56,57 proximate the corners 60 thus form acute angle greater than zero in order to ensure that the contact conductor is securely clamped to the clamp 14.

In order to allow pivotal movement of the second member 48, it is provided with a substantially cylindrically shaped pivot portion 66 about the pivot axis 50, that is received in a complementary shaped recess 64 in the first member 46.

A clamp tightening means in the form of a bolt 68 and corresponding nut 70 is arranged between the pivot axis 50 and the jaws 52,54 for tightening the opposed clamping members 46,48 together. The bolt 68 is received through cavities 72,74 traversing the members 46,48 substantially orthogonally to the vertical axis V. The bolt receiving cavity 74 of the pivotal second clamping member 48 is greater than the diameter of the bolt in order to enable sufficient pivoting of the clamping member. The second clamping portion 48 is provided with a substantially convex or curved shape between the pivot axis 50 and clamping jaw 54 to provide greater robustness when the bolt 70 is tightened.

As depicted in Figure 4, either a small diameter cable 18 may be clamped between the clamping members 56,57, or as shown in Figure 5, a larger cable 18'. Furthermore, as depicted in Figure 3, the clamp 14,16 may also be used for clamping the contact conductor. As the same clamp may be used for the various cables and conductors, a particularly cost effective arrangement is provided which may be quickly and easily assembled. Also, the eyepieces 6,8 and bridging cable may be identical.

Claims (11)

1. CLAIMS 1. A dropper assembly for mechanically and electrically interconnecting a support cable to an overhead contact conductor for supplying trains with electrical power, comprising a binder cable having eye pieces at opposite ends thereof, and first and second clamps attached to the eye pieces for clamping the dropper assembly to the support cable and the contact conductor, the first clamp comprising a first member and a second member pivotally mounted to the first member about a pivot axis proximate a mounting end of the clamp and opposed clamping jaws on the members proximate a second opposite free end of the clamp, the opposed clamping jaws comprising a first portion for receiving the support cable therebetween, and a second portion for clamping the contact conductor.
2. 2. The assembly of claim 1 wherein the second clamp member comprises a cylindrical portion defining the pivot axis and pivoted in a complementary recess of the first clamping member.
3. 3. The assembly of claim 1 or 2 wherein the first portion of the clamping jaws comprises opposed concave surfaces.
4. 4. The assembly of claim 3 wherein the second portion of the clamping jaws comprises opposed corners formed by the intersection of the concave surfaces and free end surfaces of the clamping jaws for engagement in recesses of the contact conductor.
5. 5. The assembly of any one of the preceding claims wherein the first member and a third fixing member of the clamp have complementary hook portions at the mounting end that interengage to form a substantially annular part.
6. 6. The assembly of claim 5 wherein the hook portions comprise locking faces that lie against each other, the locking faces having oblique complementary locking shoulders that interengage to lock the hook portions together.
7. 7. The assembly of any one of the preceding claims wherein each eye piece comprises a mounting portion for attachment to the binding cable, and an eye portion for engagement with the clamp mounting portion, the eye portion being annular in shape and integrally formed with the mounting portion, and the mounting portion being deformable for crimping to the binding cable.
8. 8. The assembly of claim 7 wherein each eye piece comprises a conductor cable mounting portion having a bore for receiving an end of abridging cable therein, the mounting portion being crimped to the bridging cable.
9. 9. The assembly of claim 8 wherein the bridging cable is received in a bore of one of the clamp members and is crimped thereto.
10. 10. The assembly of any one of the preceding claims wherein the eye piece and clamp positioned at one end of the binder cable are identical to the eye piece and clamp positioned at the opposite end of the binder cable.
11. 11. A dropper assembly constructed and arranged substantially as hereinbefore described with reference to the accompanying drawings.