BACKGROUND ART Railway vehicles can include a locomotive engine and a number of attached carriages. It will be appreciated that the momentum from these units can result in situations whereby the distance required to slow down and stop such units can be substantial. The stopping distance of a railway vehicle unit can be affected by human factors such as reaction time and frictional limitations with rolling wheels on a railway track. Any delays in retarding a moving unit can result in greater stopping distances, which is undesirable in emergency situations.

Conventional railway vehicle braking systems are generally aimed at retarding the rotational motion of train wheels that in turn reduces the velocity of a railway vehicle. This is achieved by way of air or disc brakes mounted to the wheels of a railway vehicle. A disadvantage with these wheel braking systems is that there are frictional limitations with applying braking pressure on wheels as the wheels can skid on the tracks, and such skidding is undesirable as it can damage the rail track.

It is an object of the invention to provide an apparatus for retarding a railway vehicle that overcomes at least some of the abovementioned problems, or at least to provide the public with a useful choice.

It is a further object of the invention to provide a method of retarding a railway vehicle that overcomes at least some of the abovementioned problems, or at least to provide the public with a useful choice.

SUMMARY OF THE INVENTION According to a first broad aspect of the invention there is provided a braking apparatus for retarding a moving railway vehicle on a rail track, the apparatus including a clamping support means attachable to a said railway vehicle, and a rail track clamping means associated with the clamping support means, the clamping means being operable by the clamping support means to move from a first raised position to a second lowered position adjacent a said railway track, and wherein the clamping means, in use, is operable by an actuator means when in the second lowered position to apply a sufficient force to clamp to the rail track to effect a braking action of the railway vehicle.

Preferably the clamping means includes a lever means pivotally connected at one end to the actuator means and to a brake pad at the other end, and having a fulcrum pivot point therebetween. Desirably the lever means includes at least two lever arms spaced apart, in use, to be pivoted about the mid section between a pivotably attached transversely aligned cross member, and having a brake pad attached adjacent the lower end of each said lever arm and having an inner frictional face, in use, for contact with the rail track, and the actuator means being transversely aligned and pivotably attached between the distal end of the lever arms, in use, to enable the brake pads to clamp the rail track when the actuator means expands.

Preferably the actuator means is a pneumatic or hydraulic ram means. Advantageously a pneumatic or hydraulic ram means is provided to move the clamping support means between the first raised position and the second lowered position.

Desirably the ram means is aligned substantially vertically to enable the clamping means to be moved substantially perpendicular to a said rail track between the first raised position and the second lowered position.

Additionally the clamping support means includes a braking bar being aligned parallel with a said railway track, and wherein the clamping means is attached to the elongate bar.

Preferably the braking bar is provided with friction brake pads on the lower face, in use, to contact a said rail track when the apparatus is moved to the second lowered position.

Preferably the outer face of the brake pads are contoured to follow the shape of the top surface of the rail track to aid in the alignment of the bar onto the rail track. Preferably a remote release means is provided to release the clamping means if an obstacle on the rail track is detected.

Alternatively two braking apparatuses are attached in opposing positions to a railway vehicle above respective railway tracks.

According to a second broad aspect of the invention there is provided a method of retarding a movable vehicle on a track using the apparatus of any one of the preceding claims, the method comprising the steps of: i. moving a clamping means from a first raised position to a second lowered position by activating the clamping support means; and ii. activating a clamping ram means to apply a clamping force to the rail track to cause a retardation of the railway vehicle.

Desirably in the step i. the clamping support means is operable by a ram means.

Preferably the method further includes the step iii. of disengaging the clamping means from the rail track.

According to a third broad aspect of the invention there is provided a computer controlled process for operating the braking apparatus in accordance with the first aspect of the invention, the processing steps comprising: a) receiving a signal to commence a braking operation; b) activating a ram means to lower the clamping means from a first raised position to a second lowered position; c) activating the clamping ram to clamp to a track and applying a clamping force; and when receiving a signal that the vehicle has stopped movement; d) deactivating the clamping ram to disengage the brake pads; and e) deactivating the ram means to raise the clamping means from the second lowered position to the first raised position.

Desirably the process further includes step f) of resetting the process from step b) when it is determined that the braking operation has been suspended.

BRIEF DESCRIPTION OF THE DRAWINGS A preferred embodiment of the invention will now be illustrated, by way of example only, with reference to the accompanying drawings in which: Figure 1 : Shows a side view of a railway carriage provided with a braking apparatus in a second lowered position according to a preferred embodiment of the invention;

Figure 2: Shows a diagrammatic end view of the braking apparatus through section A-A of figure 1; Figure 3: Shows a schematic diagram of the control means; and Figure 4: Shows a flow chart of a computer software algorithm.

DETAILED DESCRIPTION OF THE DRAWINGS Referring to figure 1, a side view of a railway carriage provided with a braking apparatus 1 in a second lowered position, and figure 2, an end view of a clamping means 5 with a braking bar 10, are illustrated.

To date, rail carriages have operated braking systems involving retarding the vehicle by retarding the rail wheels. Such braking, if applied with too much force, will cause the rail carriage to skid and this is undesirable as it can cause damage to the rail track.

Railway tracks have traditionally included a plurality of short sections of track arranged end on end between each section. In more recent years, certain modern railway lines or tracks have advantageously been constructed as a continuous track. This construction has made it more feasible to consider using the railway track as part of a braking system because it is should be relatively well anchored and immovable. The braking apparatus of the invention advantageously uses the rail track as part of the braking system.

The braking apparatus 1 of the invention desirably includes a clamping support means 2 attached to a suitably solid and robust part of a railway vehicle 7. The clamping support means 2 is preferably attached by ram means 4 and in this embodiment two ram means 4 are illustrated. In this embodiment the ram means 4 is aligned substantially vertically to enable the clamping means 5 to be moved substantially perpendicular to the rail track 6.

The clamping support means 2 is associated with a rail track clamping means 5 to enable

the clamping means 5 to be lowered from a first raised position to a second lowered position. The clamping means 5 is operable to clamp to the rail track 6 with sufficient force to effect a braking action of the railway vehicle 7.

The ram means 4 are desirably pneumatically operated although it will be appreciated that any known means to raise and lower the clamping means 5 can be provided. The ram means 4 is desirably attached to the undercarriage of the vehicle 7, and preferably between the bogie wheels 8. Such attachment of the ram means 4 is achieved to a sufficient degree to withstand the forces applied to the clamping means 5 and for stability purposes.

Therefore it will be appreciated that additional supporting members adjacent the attachment areas 9 may be provided to carry out the braking action of the invention.

Further, it will be appreciated that the apparatus 1 can be mounted to any part of a vehicle 7 suitable for withstanding substantial forces and to allow the braking apparatus 1 to be lowered adjacent a railway track 6.

The lower ends of the ram means 4 are mounted to a braking bar 10 at mounting points 11.

The mounting points 11 may be pivot points, or may alternatively be welded to a suitable bracket (not shown) on the sliding bar for a stale and permanent connection.

The braking bar 10 is preferably elongate and is aligned parallel with the rail track 6.

Advantageously the lower face of the braking bar 10 is provided with friction pads 12 to enable the bar 10 to be lowered onto the head of the rail track 6 to desirably increase the stability of the clamping operation and aid the braking action of the apparatus 1. The friction pads 12 are preferably shaped or contoured to assist in aligning the bar 10 on the head of the rail track 6. The pads 12 may be made of any suitable durable and resilient material suitable for the purpose intended. The friction pads 12 may be made of material, for example, carbon, for frictional contact with the head of a rail track 6.

The clamping means 5 is preferably attached to the bar 10 by way of a pair of transversely aligned cross tie members 13. The cross tie members 13 are desirably welded to the

braking bar 10 and have pivot joints 14 pivotably connecting the bar 10 to the lever arms 15. Preferably the pivot mounting points 14 are adjacent the mid section of the lever arms 15 to serve as fulcrum points for leverage of the lever arms 15.

A pair of brake pad shoes 16 with brake pads 17 are attached adjacent the lower end of each lever arm 15. Each brake pad 17 has an inner friction face 18 for contact with the rail track 6. The brake shoes 16 are preferably attached to respective lever arms 15 at pivot points 19. It will be appreciated that the brake shoes 16 can desirably be adapted with stops (not shown) to restrict the range of movement of the shoes 16 such that they only pivot about the pivots 19 a radius of between about 20 to 50 degrees. This is to enable the face 18 of the brake pads 17 to align with the rail track 6 when the clamping means 5 is lowered into a position to effect clamping of the rail track 6.

The distal end of the lever arms 15 are provided with an actuator means 20 in the form of a pneumatic or hydraulic ram. Preferably an hydraulic ram is provided. The ram 20 is preferably pivotably attached to the lever arms 15 at pivot joints 21. It is seen then that when the clamping means 5 is lowered such that the braking bar 10 is contacting the rail track 6, the ram means 20 can then be actuated and an outward force is applied by the ram 20 about the fulcrum points 14 to apply an extended force to the head of the rail track 6 via the brake pads 18.

As seen more clearly in figure 1, spacer members 22 are provided between the lever arms 15 to connect the ends of the rams 20 to the pivot points 21. The spacer members 22 are made of any suitable durable and resilient material to endure the forces applied by the ram 20. A fulcrum bar 23 is also desirably provided between the pivot points 14.

The ram 20 may desirably exert a force at between about 2000 to 3000 pounds per square inch (psi). It will be appreciated that the type and size of the ram 20 will depend on the amount of pressure that can be applied to the rail track 6 so as not to pull the rail track 6 away from the sleepers. It is expected that the pressure applied may be severe, and such

pressure may be dependent on what form of emergency braking system is required. It is considered that in some emergency situations, damage to the rail track is better than extensive damage to train carriages and freight, and more importantly injury to train passengers and persons that may be located just ahead of the direction of travel of the train carriage.

It will be appreciated that there may exist obstacles on and about the rail track 6 along the railway line at various points. For example, obstructions to the clamping action may occur when the rail track 6 meets switch gear, crossovers or road crossings and the like. At these areas of railway line it is envisaged that it is desirable to have a system to disengage the clamping means 5 and to reengage the line after the obstruction has passed. Desirably a pair of sensors 24 are provided at either end of the braking bar 10. The sensors 24 are configured and arranged to monitor the integrity of the rail track 6 and sense obstacles that may impede the braking abilities of the braking apparatus 1.

In this non-limiting embodiment of the invention the sensors 24 are mounted at suitable positions on an extendable arm 25, the arm 25 being mounted to the braking bar 10 and be positionable adjacent the track 6. The sensors 24 are adapted to detect undesirable obstacles on the track 6 and provide a signal to a control means 26 (as seen in figure 3). A more detailed description of the operation of the control means 26 is provided with reference to figure 3.

Referring now also to figure 3, a schematic diagram of the control means 26, is illustrated.

The control means 26 functions to control the operation of the apparatus 1 to engage and disengage the braking apparatus 1 from the rail track 6 as required. The control means 26 is a microprocessor controlled unit that monitors the operation of the apparatus 1.

An activation switch 27 for commencing operation of the apparatus 1 is desirably located in the train driver's cab. Other activation switches 27 may be located throughout the train carriages, or remotely, as required.

When the activation switch 27 is triggered, the control means 26 triggers the operation of the rams 4 to move the clamping means 5 from the first raised position to the second lowered position. A feedback signal may be provided to the control means 26 when the braking bar 10 and clamping means 5 are in the lowered position and a continuous weight is being applied to the rail track 6 by the pads 12 of the bar 10. When in the lowered position, the control means 26 activates the ram means 20 and the brake pads 18 engage the head of the rail track 6 to apply a continuous weight. When the train vehicle 7 has been stopped the clamping means 5 will disengage and the ram means 4 will operate to raise the bar 10 to the first raised position.

If an obstacle is detected on the rail track 6 during operation of the braking apparatus 1 by the sensor 24, a feedback signal will be received by the control means 26 that may disengage the clamping means 5, and then reapply the clamping means 5 at a suitable time after the obstacle has passed. A manually operated deactivation switch 28 is desirably operable to provide a feedback signal to the control means 26 to disengage the clamping means 5 when required. This sub operation may be useful if a train driver determines that the braking apparatus 1 should be disengaged by reason of false triggering of the braking apparatus 1 or an obstacle is seen ahead and manual triggering of the disengaging operation is preferred.

Referring now to figure 4, a flow chart of a computer software algorithm for carrying out the computer processing steps of the control means according to an aspect of the invention, is illustrated.

The control means 26 desirably includes a processor in the form of a computer. The computer 26 is programmed to carry out a desirable sequencing action to control the steps of the method of operation of the braking apparatus 1.

The invention includes a computer software algorithm for carrying out the control operation of the apparatus 1, the processing steps including step a. of receiving a signal that a braking action is required and commencing the braking operation with the braking apparatus 1 by initiating step b. In Step b., activation of the ram means 4 occurs to lower the clamping means 5 from a first raised position to a second lowered position. The next step c. is with activating the ram 20 to clamp the brake pads 18 to the head of the rail track 6 to apply a suitable clamping force.

When the control means 26 has received a signal that the vehicle 7 has stopped moving, or by operation of a manual switch 28, step d. operates by deactivating the ram 20 to disengage the brake pads 18. Step e. is then initiated to deactivate the ram 4 to raise the clamping means from the second lowered position to the first raised position.

In this embodiment, sensors 24 are monitoring the track 6 ahead of the braking apparatus 1 for obstacles, and, if a signal is received from a sensor 24 to either abort the braking operation or temporarily suspend the clamping action, then steps d. and e. are effected, and step f. operates whereby a predetermined period of time elapses and the process is braking sequence is reset to step b. to reactivate the ram 4 and the braking operation is continued.

In such a case it is envisaged that the computer 26 will be programmed to reset to step b. after a predetermined period of time between 1 and 10 seconds, the shorter the period of disengagement the more desirable if retarding the railway vehicle 7 is required.

The control means 26 can be activated manually via a control signal by switch 28 from the cab of the train to activate the computer 20, or alternatively by remote activation means 29 in the form of a radio signal received by a receiver 30 in the control means 26 from, for example, the control room of a railway company.

The computer 26 can also desirably be programmed to control the amount of clamping force being applied to the track 6 during use so as to limit the amount of force and thus reduce the risk of compression in the track 6 that can cause buckling or other damage to the rail track 6.

In operation, and in accordance with one non-limiting method of carrying out the steps of the invention, an emergency braking activation signal is received by the control means 26 and the control means 26 activates the rams 4 to lower the braking bar 10 so that the bar 10 is moved from a first raised position to a second lowered position onto the top surface of the track 6.

The control means 26 then activates the ram 20 to apply a clamping force to the brake pads 18 to clamp the track 6 and apply a suitable continuous clamping force.

It will be appreciated that the apparatus 1 can be located in opposing pairs at a central position on each carriage or car or sets of pairs of the apparatus 1 can be located on each car or carriage, as required.

It will also be appreciated that a fluid pressure system may be desirably incorporated adjacent the control means 26 to activate the rams.

In this embodiment the clamping means 5 includes a pair of lever arms 15 that each pivot about fulcrum points. However, It will be appreciated that a plurality of brake pads of varying arrangements, such as a fixed brake pad on one side of the rail head and a moving lever on the other side may be provided.

Wherein the foregoing reference has been made to integers or components having known equivalents, then such equivalents are herein incorporated as if individually set forth.

Accordingly, it will be appreciated that changes may be made to the above described embodiments of the invention without departing from the principles taught herein.

It will be understood that the above description is intended to be illustrative, and not restrictive. Additional advantages of the present invention will become apparent for those skilled in the art after considering the principles in particular form as discussed and illustrated. Thus, it will be understood that the invention is not limited to the particular embodiments described or illustrated, but is intended to cover all alterations or modifications which are within the scope of the appended claims.