Patent Description:
The following includes information that may be useful in understanding the present disclosure. It is not an admission that any of the information provided herein is prior art nor material to the presently described or claimed inventions, nor that any publication or document that is specifically or implicitly referenced is prior art.

An ongoing concern with the operation of railroad cars is the provision of comprehensive braking systems, including active braking systems and parking brake systems. Failure of the braking systems is the primary cause of most rail accidents, and can result in massive property damage and loss of life. Generally modern trains operate with a pressurized air braking system, which is vulnerable to failure when air pressure is lost, either rapidly or slowly, which prevents the brakes from being engaged. A particular risk is locomotive engine failure, as the locomotive engine commonly is used as the compressor system. To compensate, manual hand brakes are provided for application when the train is parked. However, setting of hand brakes must be done for each rail car, which is time consuming, difficult to track, and is still subject to risk, as often only a percentage of the hand brakes are set, based on the ratio of empty to loaded rail cars.

For example, the <NUM> train derailment in Lac-Megantic, Quebec, Canada resulting in the deaths of nearly <NUM> people and the eventual destruction of the majority of the downtown of the city from the derailment and after-effects. One of the causes of the derailment was believed to be failure of the pressure in the air pressure system for the brakes, as well as having an insufficient number of hand brakes secured. In <CIT>, a rail brake including a rigid enclosure which mounts under a crane so as to dispose the base end of the enclosure over and adjacent a rail is disclosed. A top plate is mounted underneath the upper end of the enclosure. A spring carriage is mounted for vertical translation within the enclosure, beneath the top plate. Springs are mounted between the spring carriage and the top plate so that the springs are compressed when the spring carriage is elevated. A brake shoe is mounted under the carriage. Actuators are mounted between the spring carriage and the base end of the enclosure. Extension of the actuators compress the springs and elevate the brake shoe from the rail. Retraction allows the springs to drive the brake shoe against the rail. An opening in the enclosure allows replacement of the springs and actuators. Elevation of the brake shoe provides for its inspection and maintenance. In <CIT>, a spring-type brake actuator for a pneumatically-operated vehicle brake is provided, with a brake actuator spring located on a front side of the actuator's intermediate flange, between a service brake actuator and a parking brake release actuator. The spring is captured between the intermediate flange and a retaining plate which is connected to the parking brake release actuator via a shaft through the intermediate flange. Moreover, <CIT> discloses a vehicle having a governor- actuated braking system, a disc is releasably secured to an axially outer face of a wheel and normally drives a shaft which extends through a hub on which the wheel is mounted to transmit torque from the wheel to a governor via a gear train disposed at the axially inner end of the hub.

Accordingly, there remains a need for improvements in the art to partially or completely address the above-noted deficiencies.

In accordance with an aspect of the invention, there is provided a to braking systems for rail vehicles and, more specifically, to a linear braking system for rail cars.

According to an embodiment of the invention, there is provided a linear brake assembly for a rail truck, comprising: a brake mechanism, the brake mechanism comprising at least one air brake, the air brake comprising at least a pressurized air chamber; a linear brake pad, the linear brake pad moveable between an extended position and a retracted position via operation of the brake mechanism, the extended position having the linear brake pad in contact with a rail and the retracted position having the linear brake pad not in contact with the rail; the linear brake pad defaulting to an extended position and moving to and from the retracted position via operation of the brake mechanism; wherein movement of the linear brake pad is performed via adjustment of air pressure within the pressurized air chamber of the air brake.

According to a further embodiment of the invention, there is provided a kit for a linear brake assembly for a rail truck, comprising: a brake mechanism, the brake mechanism comprising at least one air brake, the air brake comprising at least a pressurized air chamber; a linear brake pad, the linear brake pad moveable between an extended position and a retracted position via operation of the brake mechanism, the extended position having the linear brake pad in contact with a rail and the retracted position having the linear brake pad not in contact with the rail; the linear brake pad defaulting to an extended position and moving to and from the retracted position via operation of the brake mechanism; wherein movement of the linear brake pad is performed via adjustment of air pressure within the pressurized air chamber of the air brake; and one or more coupling mechanisms to secure the linear brake assembly to the rail truck.

According to a still further embodiment, there is provided a linear braking system for a rail car, comprising: a plurality of linear braking assemblies, each linear braking assembly comprising: a brake mechanism, the brake mechanism comprising at least one air brake, the air brake comprising at least a pressurized air chamber; a linear brake pad, the linear brake pad moveable between an extended position and a retracted position via operation of the brake mechanism, the extended position having the linear brake pad in contact with a rail and the retracted position having the linear brake pad not in contact with the rail; the linear brake pad defaulting to an extended position and moving to and from the retracted position via operation of the brake mechanism; wherein movement of the linear brake pad is performed via adjustment of air pressure within the pressurized air chamber of the air brake. wherein each rail truck on the rail car includes a pair of the linear braking assemblies.

For purposes of summarizing the invention, certain aspects, advantages, and novel features of the invention have been described herein. It is to be understood that not necessarily all such advantages may be achieved in accordance with any one particular embodiment of the invention. Thus, the invention may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein. The features of the invention which are believed to be novel are particularly pointed out and distinctly claimed in the concluding portion of the specification. These and other features, aspects, and advantages of the present invention will become better understood with reference to the following drawings and detailed description.

Other aspects and features according to the present application will become apparent to those ordinarily skilled in the art upon review of the following description of embodiments of the invention in conjunction with the accompanying figures.

Reference will now be made to the accompanying drawings which show, by way of example only, embodiments of the invention, and how they may be carried into effect, and in which:.

Like reference numerals indicated like or corresponding elements in the drawings.

The present invention relates to braking systems for rail vehicles and, more specifically, to a linear braking system for rail cars.

According to an embodiment as shown in <FIG>, a rail car <NUM> is carried on trucks <NUM> over rails <NUM> for travel. As shown in more detail in <FIG>, the trucks <NUM> comprise a set of wheels <NUM> with brake pads <NUM> and braking mechanism <NUM>. In modern trains, braking mechanism <NUM> operates under air pressure, with the air pressure in the mechanism <NUM> increased to apply the brake pads <NUM> to the wheels <NUM>. The body <NUM> of the truck may include a suspension mechanism (not shown), generally springs or air suspension, along with components for operating the braking mechanism <NUM>, such as air hoses, valves and the like. Note the brake pads <NUM> are shown on the exterior of the wheels <NUM> for informative purposes, and brake pads <NUM> may be located on the interior of the wheels <NUM> in alternate designs.

Referring now to <FIG>, a linear braking assembly <NUM> is attached to truck <NUM> over the existing body <NUM> to provide an additional braking option for the rail car <NUM>. Linear braking assembly <NUM> may comprise a brake shoe <NUM> which extends to contact the rail <NUM> to brake or otherwise inhibit movement of the truck <NUM>, and retracts off the rail <NUM> to permit movement. Extension and retraction are performed through the use of a spring brake <NUM>, also known as an air brake, a maxi brake or a maxi pot.

The spring brake <NUM> is designed such the that default position, when there is no air pressure in the spring brake <NUM>, is to extend the brake shoe <NUM> and engage the linear braking assembly <NUM>. Brake shoe <NUM> is extended via a heavy-duty spring connected to the brake shoe <NUM>, which forces the brake shoe <NUM> into contact with the rail <NUM>. When air pressure is increased in the spring brake <NUM>, the spring is compressed and the brake shoe <NUM> is retracted, disengaging from contact with the rail <NUM> and permitting movement of the truck <NUM> and rail car <NUM>. Advantageously, if there is an air pressure failure while the brake shoe <NUM> is retracted, the spring decompresses and the brake shoe <NUM> is extended into contact with the rail <NUM>, thereby providing a failsafe mechanism for the linear braking assembly <NUM>. Accordingly, the risk of the truck <NUM> or rail car <NUM> moving unintentionally is effectively eliminated, avoiding a potential derailment or similar disaster.

Additionally, by having the linear brake shoe <NUM> engage in contact with the rail <NUM>, as opposed to the wheel <NUM>, risks of wear and wheel damage are mitigated, as any wear is applied to the brake shoe <NUM>. Additionally, heat is dissipated by the rail <NUM>, and fresh (unheated) sections of rail <NUM> are engaged as the truck <NUM> moves, thereby avoiding any warping of the wheel <NUM>, as may be found with existing braking systems <NUM>. Further, wear on the brake shoe <NUM> itself may be reduced, as the linear contact produces a more even heat distribution and wear pattern over the brake shoe <NUM>.

As each rail car <NUM> runs on a pair of trucks <NUM>, and each truck <NUM> has a pair of wheels <NUM> on either side, the rail car <NUM> typically requires four braking assemblies <NUM>, two for each truck <NUM>, mounted on each side between the wheels <NUM>. This number may be adjusted to the size and structure of the truck as needed, although braking assemblies should be paired on opposite sides for balance.

In operation, as shown in <FIG>, each linear braking assembly <NUM> is connected to a source of pressurized air <NUM>, preferably using the same source as the pre-existing braking system on the rail car <NUM>. Further, each linear braking assembly <NUM> is communicatively coupled to a central brake control mechanism <NUM>, which permits disengagement and engagement of all linear braking assemblies simultaneously. Preferably, again, the central control mechanism <NUM> is provided near to or combined with existing controls for the pre-existing braking system.

Advantageously, use of a central brake control mechanism provides for verification that the linear braking system is engaged, as well as ensuring that any disengagement of the linear braking system must be performed intentionally.

An emergency release mechanism may also be provided to depressurize and engage the linear braking assembly <NUM> in the event of a system failure or other emergency situation that requires the linear braking assembly <NUM> to be engaged. The emergency release may be integrated into the spring brake <NUM> to permit engagement of a single linear brake assembly <NUM>. Alternatively, or additionally, an emergency release mechanism may be provided on the rail car, which engages all linear brake assemblies <NUM> attached to all the trucks <NUM> on a given rail car.

Claim 1:
Mechanism for reducing the risk of a truck (<NUM>) of a rail car (<NUM>) moving unintentionally, comprising:
A linear brake assembly (<NUM>), the linear brake assembly (<NUM>) comprising:
a brake mechanism, the brake mechanism comprising at least one air brake (<NUM>), the air brake (<NUM>) comprising at least a pressurized air chamber and a heavy duty spring;
a linear brake pad (<NUM>) coupled to the spring, the linear brake pad (<NUM>) moveable between an extended position and a retracted position via operation of the brake mechanism, the extended position having the linear brake pad (<NUM>) in contact with a rail (<NUM>) to produce the braking force and the retracted position having the linear brake pad (<NUM>) not in contact with the rail (<NUM>); the linear brake pad (<NUM>) defaulting to the extended position and moving to and from the retracted position via operation of the brake mechanism;
characterized in
that movement of the linear brake pad (<NUM>) is performed via adjustment of air pressure within the pressurized air chamber of the air brake (<NUM>), where a decrease in air pressure results the movement of the linear brake pad (<NUM>) to the extended position; and
that the linear brake assembly (<NUM>) further comprising a coupling mechanism to couple the linear brake assembly (<NUM>) to a rail truck body (<NUM>) wherein the coupling mechanism further comprises one or more connection assemblies to connect the linear brake assembly (<NUM>) to an existing brake assembly (<NUM>) on the rail truck (<NUM>), where present.