GB2375802A

GB2375802A - Rail vehicle emergency electromagnetic braking system

Info

Publication number: GB2375802A
Application number: GB0112741A
Authority: GB
Inventors: Jim Ward
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-05-25
Filing date: 2001-05-25
Publication date: 2002-11-27
Also published as: GB0112741D0

Abstract

A braking system for rail vehicles such as trains or trams, has a housing 1 in which is mounted an electro-magnet 2 held in a parked / standby position in line with and just above the rail by two bolts 11 and springs 7. Above the electro-magnet 2 are two horizontally mounted solenoids 4 with push rods 5 and 6, arranged in such a way that when the solenoids are energised the electro-magnet is pushed down against the springs, the electro-magnet which is energised at the same time is pulled onto the rail by magnetism, and will remain clamped to it while the braking system is switched on. When the braking system is switched off the electro-magnet and the solenoids become inactive and the electro-magnet will be retracted by the springs to the standby position. Control and monitoring wiring circuits are disclosed (figs 4 and 5), switches 8 and 13 detecting the system status. A sounder to prevent the system being left on accidentally, and emergency lighting 19 may be provided.

Description

EMERGENCY BRAKING SYSTEM FOR TRAINS This invention relates to an Emergency Braking System for trains, trams and other rail vehicles.

Train braking systems have changed little over many years, a train travels a considerable distance after the brakes are applied, in normal circumstances this is not a problem as the driver can start applying the brakes well in advance of the place the train is required to stop. However, in an emergency, for example, a driver whose train is traveling at high speed is suddenly faced with a road vehicle on a level crossing, the conventional braking system may not be sufficient to stop the train before it collides with the road vehicle, there have been many such incidents in recent years.

The invention discribed here is designed to work in conjunction with but completely independent of the conventional braking system and in an emergency will reduce the stopping distance considerably so that a collision may be avoided. A housing fabricated from steel plate in which is mounted an electro-magnet, this is held in a 'parked'position in line with and just above the rail by two springs, above the electromagnet are two solenoids with push rods arranged in such a way that when the solenoids are energised the electro-magnet is pushed down onto the rail, the electromagnet which is energised at the same time will be'clamped'to the rail assisted by downward force applied by the solenoids via the push rods.

The invention will now be discribed in detail with reference to the following drawings.

Figure 1 includes only the basic features of the Emergency Braking System; Figure 2 shows all the main components of the Emergency Braking Syetem ; Figure 3 shows how the Emergency Braking System is fitted to a typical bogie ; Figure 4 shows how the first locomotive/coach may be wired ; Figure 5 shows the wiring for the monitoring system: Referring to the drawings the basic Emergency Braking System comprises housing 1, electro-magnet 2, rail guides 3, solenoids 4, push rods 5 and 6, springs 7, electromagnet guides 9, guide posts 10, bolts 11, main brake switch 18, and'starting' battery 20.

The housing 1 is fabricated from steel plate of suitable thickness, the electro-magnet 2 is mounted in the bottom of the housing and held up in a'parked'position in line with and just above the rail by springs 7, mounted in the housing above the electromagnet are two powerful solenoids 4 with push rods 5 and 6 mounted in such a way as illustrated in Fig 1 and Fig 2 that when the solenoids are energised the electromagnet is pushed down against the springs, the electro-magnet which is energised at the same time is pulled by magnetism onto the rail and will remain'clamped'to it while the electro-magnet is energised (supplied with a D. C. voltage). when the voltage is switched off the electro-magnet and the solenoids become inactive and the electro-magnet will be retracted by the springs 7 to a parked/standby position.

The rail guides 3 which are vital parts of the Emergency Braking System are made from steel and case hardened will guide the electro-magnet over any imperfections in

e rail such as uneven rail joints. The extent to which the electro-magnet can be

lowered is restricted by the ends of the housing which are turned in at the bottom as ilustrated in Fig 1 and Fig 2 and also by the electro-magnet guides 9 and guide posts/stops 10, this is very important (shims and/or washers may be used for adjustment). The guides also prevent the electro-magnet'wandering'from side to side and keeps it in alignment with the rail, the thread on the guides should only be enough to allow them to be screwed into the tapped blind holes in the ends of the electro-magnet ALTERNATIVELY the guides can be screwed through with a lock nut fitted on the bottom. Replaceable bushes should be fitted in the housing where the guides (9) pass through just above the electro-magnet and also where the bolts (11) pass through, washers should be fitted between the springs and bushes, the bushes may be secured in place with grub screws. The guide posts are bolted to the housing using 2 bolts (not shown) one either side of the guide, bushes are not required as the guide posts can easily be replaced if the become worn.

The push rods and solenoids should be arranged in such away that when the braking system is switched on and the electro-magnet is in contact with the rail, push rods 5 are horizontal or nearly so bearing in mind that the top pivot points of push rods 6 are fixed. Push rods 6 should be arranged so that the are nearly vertical (left and right pairs) when the system is switched on so that maximum downward force is applied to the electro-magnet, however they must be prevented from becoming fully alligned vertically as this may prevent the electro-magnet from parking up when the braking system is switched off, this can easily be achieved if the solenoid pistons have a flange on the inside restricting there outward movement.

Strengthening plates 12 are welded on the back of the housing as shown m Fig 2, a strengthening plate (not shown) should also be welded across the back of the two solenoid angle brackets, alternatively stays can be incorporated between the top outer angle bracket bolts and the bottom solenoid fixing bolts The electro-magnet'case' may be made of two parts, the top part being made from steel plate of suitable thickness and the bottom part (the electro-magnet proper) bolted to it.

Fig 3 shows how the Emergency Braking Sysstem may be fitted to a typical bogie. A range of interface plates and/or brackets will be required for bogies of different design.

The solenoids and electro-magnets are wired in parallel as shown in Fig 4, heavy duty cable capable of carrying a large current must be used, a sounder is incorporated so that the braking system can't be left on accidentally, the system may be powered by a large battery 20, for example, the starting battery on a diesel train, on electric trains and trams a dedicated'starting'battery with charging circuit may be used Each additional coach should be hooked up by a plug and socket arrangement as illustrated in Fig 4, only the wiring for the first locomotive/coach is shown.

A monitoring system is incorporated so that the Emergency Braking System can be checked from the cab, the wiring for this is shown in Fig 5, low voltage low current cable may be used and incorporated with the cables, plugs and sockets discribed above. The system consists of 2 way 2 pole momentary (spring loaded) switches 8, magnetic sensors or reed switches 13, a 3 way 1 pole switch 14, bulbs (or L. E. D.'s) 15 and 16 and a small battery. The switches 8 and 13 are wired in series

Wng one side of the train/tram then the wires are looped around the back and

returned in a similar manner along the other side back to the control panel zig Switches 8 are operated by the electro-magnet guides 9, Fig 5 shows the system in standby with the switches pressed so that the top pair of contacts shown as the inside contacts in Fig 5 will be switched on and switch 14 set to position 2, the standby bulb 16 will be lit to indicate that the system is in standby and that ALL the electromagnets are parked UP.

The Emergency Braking System can be tested with the train/tram stationary, to do this switch the brake switch 18 to ON and the 3 way switch 14 to position 3, the bulb 15 should light to indicate that ALL the solenoids are working, ALL the electro-magnets have been lowered to the rail and ALL the electro-magnets are energised, if the bulb fails to light the cause should be investigated.

A cover made from aluminium sheet with a cutout for the lamp 19 should be fitted on the outside, this should be hinged at the top with clips at the bottom, the cover should extend down to about half way over the electro-magnet, the bottom edge should be bent out. As the title suggests the braking system should only be used in emergencies and therefore require very little maintenance.

Emergency Lighting is also incorporated so that if a train has broken down or halted for some reason at night, for example, a landslide, flooded track or derailment, the passengers can get off and away from the train in safety. The emergency lighting consists of a bulkhead style lamp 19, a back-up battery connected to the lamp via a relay (not shown), the lamp and relay negatives are connected to the common negative at the solenoids and the positive via a 2 way switch, one position connected to the switched side of the brake switch 18 NORMAL POSITION and the other directly to the battery positive, so that the Emergency Lighting can be used independently. When the Emergency Braking System is activated the lamps will be switched on AND the relays will be triggered-supplied by the'starting'battery 20, if the supply is interrupted, for example, due to a derailment causing the coaches to de-couple, each lamp will continue to work until its back-up battery is exhausted.

Suitable washers with locking tabs should be used on all nuts and bolts and locking grub screws where appropriate.

Fuses of suitable current rating should be incorporated in the supply.

In certain circumstances the Monitoring System and/or the Emergence Lighting may be omitted, for example the Emergency Lighting would not be required on a tram /metro system traveling between towns/citys using roads and streets with street lighting.

Economy Version: Where cost is a magor consideration, the monitoring system, emergency lighting, AND the solenoids/pushrods may be omitted. OR any combination of these

Claims

CLAIMS 1 An emergency braking system for trains, trams, and other rail vehicles, to work in conjunction with but completely independent of the conventional braking system.

A housing fabricated from steel plate in which is mounted an electro-magnet, this is held in a standby position in line with and just above the rail by two bolts and springs.

The electro-magnet when switched on is'pulled'onto the rail and will remain 'clamped'to it until switched off, the electro-magnet is then returned by the springs to the standby position.
2 An emergency braking system for trains as claimed in claim 1 wherein solenoids are provided to create a downward force upon the electro-magnet.
3 An emergency braking system for trains as claimed in claim 1 or claim 2, wherein push rods are provided to maximise the pushing force of the solenoids and also to enable the solenoids to be mounted horizontally.
4 An emergency braking system for trains as claimed in any preceding claim, wherein guides are provided to guide the electro-magnet over any imperfections in the rails.
5 An emergency braking system for trains as claimed in any preceding claim, wherein means are provided at the bottom ends of the housing to restrict the downward movement of the electro-magnet.
6 An emergency braking system for trains as claimed in any preceding claim, wherein guide means are provided to keep the electro-magnet in alignment with the rail.
7 An emergency braking system for trains as claimed in any preceding claim, wherein means are provided to arrest the downward movement of the electro-magnet using the guides and guide posts.
8 An emergency braking system for trains as claimed in any preceding claim, wherein a means is provided in the cab for checking that the braking system is in standby and serviceable.
9 An emergency braking system for trains as claimed in any preceding claim, wherein a means is provided in the cab to indicate whether the braking system is working.
10 An emergency braking system for trains as claimed in any preceding claim, wherein a means is provided in the cab to indicate whether the electro-magnet is active.
11 An emergency braking system for trains as claimed in any preceding claim, wherein emergency lighting with independent battery back-up is provided.
12 An emergency braking system for trains substantially as discribed herein with reference to Figures 1-5 of the accompanying drawings.