GB2041608A - Body mis-alignment detection system - Google Patents

Abstract

A body mis-alignment detection system, e.g. a railway wagon derailment detection system, in which the lateral limits of a body's path are defined by a trip-wire arrangement in one embodiment and a photo-electric beam arrangement in an alternative embodiment, is disclosed. In the trip-wire arrangement, the trip-wires are connected to earth leakage current sensing means so that when a contact is made between the trip-wires and a mis- aligned body, the contact is detected and an alarm energized or other action triggered. In the photo-electric beam arrangement, beam continuity is sensed continuously by photo-electric detectors; thus, immediately upon beam interruption by a mis-aligned body similar action is initiated.

Description

SPECIFICATION A body mis-alignment detection system The invention relates to body mis-alignment detection systems, particularly, but not exclusively, railway wagon derailment detection systems.

The probability of railway bulk container wagons, for example coal wagons, being derailed during loading or unloading is significant due to the buiid-up of material over the track which lifts the wagon wheels clear of the rails. Once derailed in this way, the wagons are easily displaced relative to the track, blocking the track and causing delay and also possibly damaging trackside equipments.

More generally, problems can arise in any arrangement for moving bodies or containers along predetermined paths where there exists the possibility that a body or container can become displaced laterally with respect to the path, such as, for example, in remotely driven conveyor arrangements.

In such circumstances, particularly in the case of railway wagons, it clearly is desirable if the situation can be detected as quickly as possible and remedial action undertaken.

According to the present invention there is provided a body mis-alignment detection system comprising longitudinally extending path limit defining means spaced laterally with respect to a predetermined path a body or plurality of bodies is expected to follow, and path limit infringement detecting means responsive to infringement of the lateral path limits to detect mis-alingment of a body on the path.

In one arrangement of the invention, for detecting derailment of a railway wagon, the limit defining means comprises a photo-electric beam system and the infringement detecting means is responsive to interruption of the photo-electric beam. Alternatively, the limit defining means is an electric trip-wire system, electrically insulated from earth and maintained at a relatively low potential with respect to earth, and the infringement detecting means is earth leakage trip system. Preferably the limit defining means is positioned above head height relative to track level and is retractable to a protected position, further from the track than its preferred operating position to allow wider vehicles, such as locomotives, to pass the retracted system unimpeded and to detect the minimum mis-alignment of vehicles in the deployed operating position.

The invention will now be described by way of example, with reference to the accompanying drawings, wherein Figure 1 shows a schematic plan view of a railway wagon derailment detection system, Figure 2 shows a plan view of a trip-wire post mounting arrangement, Figure 3 shows an electrical diagram of a trip-wire detection system, and Figure 4 shows at (a) and (b), plan and side elevation views respectively of a photo-electric beam post mounting arrangement.

Referring now to the drawings, Figure 1 shows a schematic plan view of a railway wagon derailment detection system installed at a power station coal hopper. At such an installation, coal is normally delivered in bottom-discharging wagons which are hauled over a track 1 laid across the mouth of the hopper and the coal is discharged into the hopper through a grid laid between the tracks. The problem with such an arrangement is that from time-to-time faults occur which lead to a build-up of coal on the track so that the wheels of following wagons are lifted from the track, permitting easy displacement of the wagons relative to the tracks. Such faults are, for example, halting of the coal transport conveyor in the hopper, malfunction of the hopper level detector, and the dumping of several successive wagon loads in the same spot.The wagon derailment detection system is designed to function to detect as early as possible mis-alignment of the wagons so that the train can be halted before the sitation develops out-of-hand.

On entering the hopper-receiving area, the wagons pass through a photo-electric wagon sensor, generally indicated at2, comprising three pairs of photo-electric source-detector units producing beams 3, 4and 5. The two outer beams 3,5 are spaced apart by the distance of one wagon pitch, i.e.

by slightly more than the distance between wagon container end walls, thus when the centre beam 4 only is broken and the outer beams 3,5 are unbroken, a wagon is sensed, if all three beams are broken simultaneously, a larger vehicle, i.e. a hauling locomotive, is sensed. Generally when the sensor detects a wagon, the derailment detection system is deployed into its operative position, i.e.

the derailment detecting means are extended from the trackside housings 6-13 inclusive, to define path limits extending longitudinally each side of the track 1 over the length of the hopper area. The sensitivity of the system is directly related to the spacing of the detectiing means from the wagon sides, thus the closerthe longitudinal path limits can be brought to the track, the more sensitive and responsive will be the detection system.Unfortunately, locomotives tend to be wider than the coal wagons they haul, therefore in the embodiment of Figure 1, the limitdefining means is deployed in sections commencing with detection of the first wagon after a locomotive by the sensor 2. Once the locomotive has passed the first trackside units 6, 7 and 10, 11 are extended to define the first section, subsequently units 8 and 12 are extended to define the second section, and so on, here the third and final section is defined when units 9 and 13 are extended. Where a dummy wagon or a wire-hauling system is employed, all three detection systems may be extended simultaneously.

As mentioned previously, the path limit defining means may comprise either a photo-electric beam system or an electric trip-wire system. The trip-wire system is shown in more detail in Figures 2 and 3.

The trip-wire 20 is quarter-inch diameter nylon shrouded wire or eighth-inch stainless steel wire strung between adjacent pairs of mounting posts along each side of the track. The ends of the wires in each second are crimped to ceramic insulators 21 supported by studs 22 mounted in retaining blocks 23. The arrangement is designed to be dismountable when a force marginally in excess of that exerted by the normally strung wires is exerted on the mounting. The studs 22 may be retained by locking ball bearings 24 gripping the stud shanks or, alternatively, frangible studs designed to break at the required force, may be used. The mounting block 23 is in turn attached to one end of a rod 25 slideably supported on a mounting post 26 for movement between retracted and extended positions by means of a pneumatic cylinder 27 arrangement.

The control system for cylinder 27 is arranged such that the rod 23 is extended, to the position shown in Figure 2, either in response to a signal from the wagon sensor2 (Figure 1) orby manual command, and that the rod is retracted by manual command, or automatically in response to a locomotive being detected by wagon sensor2, in the event of a failure, or on detection of a wagon derailment at the same tine as an appropriate alarm is given. The automatic retraction feature is preferred so that the trip-wire system is saved from damage whenever or wheresoever possible.To facilitate replacement of the trip-wira and its mounting arrangement should damaqe occur, the rod 25 is formed in two sections joinei: at 28, thus the pneumatic cylinder 27 on the poz 26 need not be removed. The trip-wire 20 is conneced to an electrical sensing system, shown in Figure 3, by means of the free ends 29 of the wires passing through guide rods 30, 31 retractable with the rod 25 into the weatherproof housing 32 which protects and houses the sensing unit of Figure 3.

The trip-wire 20 is looped between terminals 33, 34 which are connected to respective current paths 35,36 through an earth leakage current sensing-type circuit breaker unit 37, the two paths of which are connected to opposite ends of a secondary winding 38 of a mains isolating transformer 39. The electrical earth wire 40 entering the system is also connected to the running rails of the railway track 1. In operation, when a wagon is derailed and contacts trip-wire 20, a circuit to earth is completed by the wagon and the current sensing circuit breaker unit 37 energises and open contacts in both current paths 35,36 isolating the trip-wire 20 from the voltage source, secondary winding 38.

Inserted in series with current path 35 and tripwire 20 is a relay 41 electrically sensed to be normally energised by the trip-wire voltage and connected in the control circuit of the pneumatic cylinder 27. Thus, when a wagon is derailed, the relay "drops out" and the pneumatic control circuit is reversed, retracting the rod 25. A further set of electrical contacts on the relay 41 are used to complete an alarm circuit which can also be adapted to stop a train or winding gear hauling the wagons.

Preferably, the trip-wire is mounted above head height, high enough to avoid accidental contact by humans but still sufficiently low to be contacted buy a wagon coming away from the track. An earth touch bar or magnetic stainless steel Strip may be mounted at the corners of the wagons to ensure good electrical contact with the trip-wire.

Figure 4 shows a second embodiment of the invention, in plan at (a), and in elevation at (b), and in which like parts have like references. Here a photoelectric unit, generally indicated at 42, is mounted on the outer end of rod 25 in a protective cover 43. The photo-electric devices in units 6, 10 (Figure 1) comprise only light sources, and in units 9,13, only light detectors. The remaining units 7,8 and 11, 12 comprise appropriately facing sources and detectors mounted back-to-backto form substantially continuous light beams along either side of the track 1.

The sensing electronics (not shown) for sensing disruption of either of the two sets of beams may be any suitable form, well-known to those skilled in the electronics art, and adapted to function analogously to the trip-wire sensing system already described.

In alternative or more general applications of the invention, as foreshadowed above, certain aspects of the abeve-described embodiments may be varied or alters as appropriate or required to suit circumstances. without departing from the principle bf the in" ion as described. Clearly, for example, the scale and relative magnitude of various integers may be changed from those described or implied above.

Claims (21)

1. A body mis-alignment detection system comprising longitudinally extending path limit defining means spaced laterally with respect to a predetermined path a body or plurality of bodies is expected to follow, and path limit infringement detecting means responsive to infringement of the lateral path limits to detect mis-alignment of a body on the path.

2. A body mis-alignment detection system, according to Claim 1, wherein the predetermined path is a railway line and the or each body is a railway wagon

3. A mis-alignment detection system according to Claim 1 or Claim 2, wherein the path limit defining means comprise voltage carrying electric trip-wires and the path limit infringement detecting means comprise current sensing means connected in series with the electric trip-wires.

4. A system according to Claim 3, wherein the electric trip-wires are electrically insulated from earth and the or each body carries an earthed conductor, preferably at each corner thereof, arranged to contact the trip-wire in the event of path limit infringement.

5. A system according to Claim 3 or Claim 4, wherein the electric trip-wires are arranged substantially as described herein with reference to Figure 3.

6. A system according to Claim 3, Claim 4 or Claim 5, wherein the trip-wires are rigged by means of electrically insulating supporting means.

7. A system according to Claim 6, wherein the electrically insulating supporting means is substantially as described herein with reference to Figure 2.

8. A mis-alignment detection system according to Claim 1 or Claim 2, wherein the path limit defining means comprise light beams and the path limit infringement detecting means comprise photoelectric sensing means.

9. A system according to Claim 8, wherein light emitting means are arranged to produce light beams axially aligned with the photo-electric sensing means.

10. A system according to Claim 9, wherein the light emitting means and the photo-electric sensing means are mounted by means of respective supporting means.

11. A system according to Claim 10, wherein the supporting means is substantially as described herein with reference to Figure 4(a) and (b).

12. A system according to Claim 6 or Claim 7 or, Claim 10 or Claim 11, wherein the supporting means is movable between a first operational or deployed position and a second non-operational or retracted position.

13. A system according to Claim 12, wherein the second non-operational ortetracted position is spaced laterally at a greater distance from the predetermined path than the operational or deployed position.

14. A system according to Claim 12 or Claim 13, wherein movement of the supporting means between its first and second position is controlled by deployment control means.

15. A system according to Claim 14, wherein the deployment control means is manually operable.

16. A system according to Claim 14, wherein the deployment control means is arranged to automatically retract the supporting means in response to detection of path limit infringement.

17. A system according to Claim 14 or Claim 16, wherein the deployment control means is arranged to automatically deploy the supporting means in response to the present of a body on the predetermined path.

18. A system according to Claim 17 when dependent from Claim 2, further including means for detecting the presence of a railway wagon.

19. A system according to any preceding claim, wherein the path limit defining means comprises a plurality of successive sections.

20. A system according to Claim 19 when dependent upon Claim 16, Claim 17 or Claim 18, wherein each section is successively deployed in response to the progress of a body along the predetermined path.

21. A body-misalignment or railway wagon derailment detection system substantially as herein des^ribed with reference to Figure 1.