DESC:FIELD OF THE INVENTION
The present invention relates to the field of public transport system, particularly to public rail transport system. More particularly, the present invention relates to a flexible brake hose system. Further the present invention relates to a method of working of the flexible parking brake hose system.

BACKGROUND OF THE INVENTION
Metro-train/Rolling stock in the current market uses spring actuated/applied and air released parking brakes. Therefore, pressurized air (Main reservoir Pressure) is required to keep the parking brakes in released condition while train is in motion. The pressurized air has to pass through a single hose pipe fitted between car body and bogie and again through a hose pipe fitted between bogie and Tread Brake Unit (TBU)/Brake Caliper. Hose pipes are used to transfer the pressurized air between metal pipes/components to accommodate the relative motion between them. There is a relative movement between bogie and car body and therefore hose pipe is used to accommodate the relative motion between car body and bogie.

In case, when train is in motion/running in mainline/operation, any one of the parking brake flexible hose bursts, the parking brakes will get applied automatically in particular wheel set/bogie and result in wheel sliding and wheel flattening in that particular wheel set/bogie.

Secondly, to release parking brake in the hose-burst bogie train operator has get down from the train to release the parking brake by isolating parking brake cock & manually release the parking brake through remote release cable of affected bogie.

The existing technology uses the single flexible hose pipe to connect parking brake line stainless steel pipes between car body & bogie and single flexible hose pipe to connect parking brake line stainless steel pipes with Tread Brake Unit/Brake Caliper to keep spring actuated parking brakes in release condition when the train is in mainline/operation/movement. In case, any one of the parking brake flexible hose burst, the parking brakes will get applied automatically in particular wheel set/bogie and result in wheel flattening in that particular wheel set/bogie.

To overcome the all above problem, redundancy of parking brakes hose pipe using Air-flow cut-off valves (also called as auto-cut off valve) at both ends of flexible parking brake hoses can be provided.

OBJECTS OF THE INVENTION
It is the primary object of the present invention to provide a flexible brake hose system.

It is another object of the present invention to provide a method of working of the flexible parking brake hose system.

It is another object of the present invention that relates to redundancy of parking brake hose as preventive measures to prevent wheel flatness due to hose burst.

It is another object of the present invention to provide a system for preventing the unwanted spring applied parking brake application due to hose pipe bursting when the train is in motion.

It is another object of the present invention a redundancy of parking brakes hose pipe using air flow cut off valves at both ends of flexible parking brake hoses is provided.

It is another object of the present invention in case of one parking brake hose burst, the pressurized air can be fed automatically to parking brake cylinder though other hose arrangement to keep parking brakes in released condition.

It is another object of the present invention wherein the air flow cut off valves are designed to work in pair. The air flow cut off valves automatically isolate a burst or severely leaking parking brake hose and maintain a flow path for full air supply pressure through the other sound hose or healthy hose.

It is another object of the present invention wherein the air flow cut off valves comprising of two chambers separated by a flexible diaphragm, each chamber is connected to a common air supply port. Each chamber has a separate port into which a flexible hose is connected. The two flexible hoses connect between the two air flow cut off valves.

It is another object of the present invention wherein a small choke hole in the diaphragm allows sufficient air to pass to the failed hose to give an audible indication of leakage.

SUMMARY OF THE INVENTION
One or more of the problems of the conventional prior art may be overcome by various embodiments of the present invention.

A parking brake system of a railway vehicle controls the parking brakes in a release condition when one of the parking brake hose fails, comprising a main reservoir filled with compressed air used for various pneumatic operations and fitted in a railway vehicle, a Brake Control Unit (BCU) for application and release of brake for each coach/bogie in the railway vehicle and it is connected to double check valve (4), a Parking Brake Magnetic Valves (PBMV) is actuated via electric impulse, a double check valve with two inputs and one output, a parking brake cock to isolate the parking brake line air pressure for each bogie, a plurality of air flow cut off valves, a plurality of union connectors, and a plurality of stainless-steel pipes.

It is another aspect of the present invention, wherein the bogie includes atleast two flexible parking brake hose, a Tread Brake Unit (TBU) integrated with a parking brake cylinder, and a remote release handle coupled to each TBU.

It is another aspect of the present invention, wherein the air flow cut off valves are connected to both the ends of the flexible parking brake hose.

It is another aspect of the present invention, wherein the air flow cut off valves automatically isolate the failed parking brake hose and maintain a flow path for full air supply pressure through the other healthy hose.

It is another aspect of the present invention, wherein the air flow cut off valves includes a hose port, a choke hole, a flexible diaphragm, a diaphragm sealing face and a main air supply port.

It is another aspect of the present invention, wherein the air flow cut off valves includes two chambers separated by a flexible diaphragm.

It is another aspect of the present invention, wherein each chamber is connected to a common air supply port.

It is another aspect of the present invention, wherein each chamber includes a separate port to connect the flexible parking brake hose.

It is another aspect of the present invention, wherein the choke hole in the flexible diaphragm allows sufficient air to pass to the failed brake hose to give an audible indication of leakage in the brake hose.

It is another aspect of the present invention, wherein the two flexible parking brake hose connects the parking brake line stainless steel pipes with the TBU to maintain a spring actuated parking brakes in release condition while the railway vehicle is in operation.

It is another aspect of the present invention, wherein a parking brake line stainless steel pipes connects the bogie and a car body together.

It is another aspect of the present invention, wherein the pressurized air from the main reservoir maintains the parking brakes in released condition while the railway vehicle is in operation.

It is another aspect of the present invention, wherein the pressurized air from the main reservoir passes through the two flexible parking brake hose fitted between the car body and the bogie and through the two flexible parking brake hose fitted between the bogie and the TBU.

It is another aspect of the present invention, wherein the BCU receives electric brake signal from an electronic brake control unit (EBCU).

It is another aspect of the present invention, wherein the BCU transforms the received electric brake signal from the EBCU into pressure and deliver the pressure to the brake cylinders.

It is another aspect of the present invention, wherein the PBMV connects the main reservoir and the parking brake cylinder when the parking brake is released.

It is another aspect of the present invention, wherein the wherein the PBMV block the main reservoir line and vent the parking brake cylinder when the parking brake is applied.

It is another aspect of the present invention, wherein the double check valve allows higher pressure to pass and block the entry of low pressure.

It is another aspect of the present invention, wherein the double check valve maintains the combined pressure and spring force within the spring force pressure when the parking brake is applied.

It is another aspect of the present invention, wherein the parking brake cock includes a venting port and works on negative logic.

It is another aspect of the present invention, wherein the remote release handle activates emergency release gear on the brake cylinder and spring actuator to release the spring and manually applies the parking brake.

BRIEF DESCRIPTION OF THE DRAWINGS
The manner in which the features, advantages and objects of the invention, as well as others which will become apparent, may be understood in more detail, more particular description of the invention briefly summarized above may be had by reference to the embodiment thereof which is illustrated in the appended drawings, which form a part of this specification. It is to be noted, however, that the drawings illustrate only a preferred embodiment of the invention and are therefore not to be considered limiting to the invention's scope as it may admit to other equally effective embodiments.
Fig. 1 illustrates the schematic diagram of parking brake system of a railway vehicle, in accordance with an embodiment of the present invention.
Fig. 2 illustrates the schematic view of the air flow cut off valve, in accordance with an embodiment of the present invention.
Fig. 3 illustrates the flow chart of the pressurized air flow from the main reservoir, in accordance with an embodiment of the present invention

DESCRIPTION FOR DRAWINGS WITH REFERENCE NUMERALS:
(1) Main Reservoir
(2) Brake Control Unit (BCU)
(3) Parking Brake Magnetic Valves (PBMV)
(4) Double Check Valve
(5) Parking Brake Cock
(6) Bogie
(7) Air Flow Cut Off Valves
(8) Flexible Parking Brake Hose
(9) Tread Brake Unit (TBU) integrated with parking brake cylinder
(10) Remote Release Handles
(11) Hose Port
(12) Choke Hole
(13) Flexible Diaphragm
(14) Diaphragm Sealing Face
(15) Main Air Supply Port

DETAILED DESCRIPTION OF INVENTION
It is to be understood that the present disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings. This particular form is only an exemplary embodiment and is not intended to be taken restrictively to imply any limitation on the scope of the present invention. The present disclosure is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting.

The present invention relates to the field of public transport system particularly to public rail transport system. More particularly, the present invention relates to a flexible brake hose system. Further the present invention relates to a method of working of the flexible parking brake hose system.

In Metro-Train/Rolling stock, the parking brakes are used when train is parked in depot/ in main line as a standby train. The tread brake units (TBU) also known as brake calipers are fitted with integrated spring applied air released parking brake feature. Air pressure from the main reservoir equalizing pipe is fed to the parking brake cylinder.

The application or release of the parking brake actuators of spring-applied type is controlled by the impulse magnet valve, which only needs a short train lined impulse from the driver to apply and release the parking brake When there is no air in the parking brake cylinder, the force of the actuator springs is transmitted to the brake blocks/ pads and hence parking brake gets applied.

The conventional method uses the single flexible hose pipe to connect parking brake line stainless steel pipes between car body and bogie and single flexible hose pipe to connect parking brake line stainless steel pipes with the brake Caliper to keep spring actuated parking brakes in release condition when the train is in mainline/operation/movement.

In case, any one of the parking brake flexible hose bursts, the parking brakes will get applied automatically in particular wheelset/bogie and result in wheel flattening in the bogie.

Secondly, to release parking brake in the hose-burst bogie train operator has get down from the train to release the parking brake by isolating parking brake cock & manually release the parking brake through remote release cable of affected bogie.

Fig. 1 illustrates the schematic diagram of parking brake system of a railway vehicle, in accordance with an embodiment of the present invention. A parking brake system (100) of a railway vehicle controls the parking brakes in a release condition when one of the parking brake hose fails, comprising a main reservoir (1), compressed air from a Brake Control Unit (BCU) (2), a Parking Brake Magnetic Valves (PBMV) (3), a double check valve (4), a parking brake cock (5), a bogie (6), a plurality of air flow cut off valves (7), a plurality of union connectors, and a plurality of stainless-steel pipes.

During application or release of the parking brake actuators of spring-applied type integrated in TBU (9) is controlled by the impulse magnet valve PBMV (3), which only needs a short train lined impulse to apply and release the parking brake through push button installed in the driver cab. It can be also manually operated by push rod at the valve, in the case the control voltage failure.

The parking brake can also be released manually through remote release handle (10) present in the parking brake actuator in case parking brake gets applied due to unavailability of main reservoir pressure in parking brake cylinder of TBU (9). The release handle (10) is accessible from track level without the need to reach underneath the car.

In an embodiment, anti-compounding is taken care by using double check valves (4) in the circuit. In the event of brake (i.e. service/emergency brakes applied) and parking brake applied double check valve will ensure that the combine pressure and spring force will never exceed the spring force pressure. When the MR pressure drop below brake cylinder (BC) pressure in the Parking brake chamber the BC pressure enters the Parking brake chamber thus nullify the same amount of BC pressure against spring force which is applied through brake chamber. Hence at any time the total force exerted by the brake block will never be more than the spring force. Parking brake line pressurized air supply can be isolated at each bogie by isolating cock (5) with electric feedback.

In an embodiment, when the service/emergency brake are in applied condition and the parking brakes in released condition, the 8-10 bar pressurized air flows from the main reservoir (1) to parking brake cylinder of TBU (9) via PBMV (3), double check valve (4), parking brake cock (5), air flow cut off valve (7), parking brake line flexible hoses (redundant) (8). The pressurized air for braking (2) flows to service/emergency brake cylinder of TBU/Brake caliper (9).

During service/emergency brake released condition, there is no brake cylinder pressure (2) in service/emergency brake cylinder of TBU (9) and the main reservoir (1) flows to parking brake cylinder of TBU (9) via PBMV (3), double check valve (4), parking brake isolation cock (5), air flow cut off valves (in pair) (7), redundant flexible hoses (8).

When a train is in motion (i.e. service/emergency and parking brakes are in released condition), and if one of the parking brake line hose bust/ ruptured, the air flow cut-off valves (7) automatically isolate a burst or severely leaking parking brake hose and maintain a flow path for full air supply pressure through the other sound/healthy hose thereby avoid unintended application of parking brakes.

The SS pipes are used to transfer pressurized air from main reservoir to tread brake unit (TBU) (9) and the union connectors are used to join the various SS pipes with the other pneumatic components e.g., PBMV (3), double check valve (4), isolation cocks (5), air flow cut-off valves (8), TBU (9) etc.

In an embodiment, the bogie (6) includes atleast two flexible parking brake hose (8), a Tread Brake Unit (TBU) (9), and atleast two remote release handles (10). The air flow cut off valves (7) are connected to both the ends of the flexible parking brake hose (8).

In an embodiment, the air flow cut off valves (7) are designed to work in pairs, one in each end of the flexible parking brake hose (8). The air flow cut off valves (7) automatically isolate a burst or severely leaking parking brake hose and maintain a flow path for full air supply pressure through the other sound hose or healthy hose. The pressurized air flow from the main reservoir (1) is shown in Fig. 3.

In an embodiment, 2 nos. of parking brake flexible hose (8) between car body and bogie (6) to accommodate relative motion between car body and bogie and for redundancy in case of air leakage or bursting of one flexible hose. Flexible hoses are connected to 1 no. air flow cut-off valve at bogie (6) side.

The air flow cut off valves (7) comprises of two chambers separated by a flexible diaphragm (13). Each chamber is connected to a common air supply port as shown in Fig. 2. The air flow cut off valves (7) includes a hose port (11), a choke hole (12), a flexible diaphragm (13), a diaphragm sealing face (14) and a main air supply port (15). Each chamber has a separate port into which a flexible hose is connected. The two flexible hoses are connected between the two-air flow cut off valves (7).

Airflow cut off valves are used in pairs i.e. both ends of flexible hoses are connected to auto cut off valves. In parking brake air line, there are two places where flexible hoses are provided: 1. Between car body & bogie and 2. On bogie between S.S. pipes/fittings to TBU (9).

Air flow cut off valves one input & two output are connected/fitted with union connectors. Therefore, auto flow cut off valve with union connector fitted at one end (i.e. input to auto flow cut off valve) is connected to SS pipes and other end with union connectors (out of auto cut off valves) are connected to flexible hose pipes refer Fig. 1 & Fig. 3.

In the event of a burst or seriously leaking flexible hose, the pressure loss on one side forces both valve's diaphragm across to seal on the flat sealing face (14) on the burst hose side. This isolates the burst hose and maintains full main air supply pressure via the other side of the diaphragm to the remaining sound hose or healthy hose.

In an embodiment, the choke hole (12) in the diaphragm as shown in the Fig. 2 allows sufficient air to pass to the failed hose to give an audible indication of leakage in the hose. Once the fault hose is repaired, pressure is restored to both sides of the diaphragm which repositions centrally between the side covers.

Fig. 3 illustrates the operational flow chart of the pressurized air flow from the main reservoir (1) to the to parking brake cylinder in TBU (9) in different scenarios:
Scenario 1:
When a service/emergency brakes in applied condition and spring applied parking brakes in released condition: Ref. Fig.-1 & Fig.-3, During application of service/emergency brake & parking brakes in released condition, the pressurized air for braking (2) from BCU flows to ‘service/emergency brake cylinder of TBU/Brake caliper (9). The double check valve (4) will not allow pressurized air for braking (2) to go to the parking brake cylinder of TBU (9) and MR pressure (1) 8-10 bar flows to parking brake cylinder of tread brake unit (TBU) (9) via PBMV (3), double check valve (4), parking brake isolation cock (5), air flow cut off valves (in pair) (7), redundant flexible hoses (8).

Scenario 2:
When the service/emergency brakes in released condition & spring applied parking brakes in released condition: Ref. Fig.-1 & Fig.-3, During service/emergency brake released condition & parking brakes in released condition, there is no brake cylinder pressure (BC) (2) flowing to service/emergency brake cylinder of Tread brake unit (TBU) (9), the double check valve (4) will not allow MR pressure (1) 8-10 bar flows to service/emergency brake cylinder of TBU (9) and MR pressure (1) 8-10 bar flows to parking brake cylinder of tread brake unit (TBU) (9) via PBMV (3), double check valve (4), parking brake isolation cock (5), air flow cut off valves (in pair) (7), redundant flexible hoses (8).

Scenario 3:
When the service/emergency brakes in applied condition & spring applied parking brakes in released condition: Ref. Fig.-1 & Fig.-3, there is no pressurized air between A3 port of double check valve (4) and PBMV (3), hence brake cylinder pressure (BC) from BCU (2) will pass to both brake cylinder (for service/emergency brakes) of TBU (9) and parking brake cylinder of TBU (9) via A1 to A2 port of double check valve (4), parking brake isolation cock (5), air flow cut off valves (7), parking brake line flexible hoses (8). Due to anti-compounding, double check valve (4) will ensure that the combined pressure and spring force will never exceed the spring force pressure. The BC pressure from BCU (2) enters the Parking brake chamber thus nullify the same amount of BC pressure against spring force which is applied through brake chamber

Scenario 4:
When the service/emergency brakes in released condition & spring applied parking brakes in applied condition: This is generally applicable to standstill condition of train for long time when BC pressure & MR pressure falls down to zero bar due to air leakages or non-availability of compressed air from BCU (2) & from MR pressure (1). Ref. Fig.-1 & Fig.-3, there is no pressurized air either side of the double check valve (4) and hence spring actuated parking brakes gets applied. Parking brakes should be in applied condition through PBMV (3) only in STANDSTILL condition.

During normal operation, the air flows through both of the parking brake hoses. In the above scenarios if one of the parking brake hose is bust/ ruptured or one of the flexible hose is loosen, the air flow cut-off valves (7) automatically isolate a burst or severely leaking parking brake hose and maintain a flow path for full air supply pressure through the other sound/healthy hose.

The present invention is clearly advantageous in providing a technical solution to the problems of the prior art. The use of air flow cut off valves (7) automatically isolate a burst or severely leaking parking brake hose and maintain a flow path for full air supply pressure through the other sound hose in the parking brake system (100) of a railway vehicle. It is also advantageous in avoiding manual release of the parking brake by a train operator through remote release handle (10) and isolate the parking brake cock (5) of affected bogie (6). The parking brake system (100) of a railway vehicle can be used in the rolling stock, metro trains, locomotives, diesel electrical multiple unit (DEMU), mainline electrical multiple unit (MEMU), CMV (OHE Inspection car), rail coach, wagons, and high-speed trains wherever spring applied and air release parking brakes are used.
,CLAIMS:WE CLAIM:
1. A parking brake system (100) of a railway vehicle controls the parking brakes in a release condition when one of the parking brake hose fails, comprising:
a main reservoir (1) filled with compressed air used for various pneumatic operations and fitted in a railway vehicle;
a Brake Control Unit (BCU) (2) for application and release of service/emergency brake for each coach in the railway vehicle and it is connected to Brake cylinder/chamber of TBU (9) and double check valve (4);
a Parking Brake Magnetic Valves (PBMV) (3) is actuated via electric impulse, and it is connected to double check valve (4);
a double check valve (4) with two inputs (one from BCU (2) and one from PBMV (3)) and one output connected to parking brake cock (5);
a parking brake cock (5) to isolate the parking brake of each bogie (6) and it is connected to air flow cut off valve (7) at coach/car body side which in turn connected to two flexible parking brake hoses (8) between car body/coach and bogie (6).
a bogie (6);
a plurality of air flow cut off valves (7);
a plurality of union connectors; and
a plurality of stainless-steel pipes,
wherein the bogie (6) includes atleast two flexible parking brake hose (8), a Tread Brake Unit (TBU) (9) integrated with a parking brake cylinder, and a remote release handle (10) coupled to each TBU (9),
characterised in that the air flow cut off valves (7) are connected to both the ends of the flexible parking brake hose (8),

wherein the air flow cut off valves (7) automatically isolate the failed parking brake hose and maintain a flow path for full air supply pressure through the other healthy hose.

2. The parking brake system (100) of a railway vehicle as claimed in claim 1, wherein the air flow cut off valves (7) includes a hose port (11), a choke hole (12), a flexible diaphragm (13), a diaphragm sealing face (14) and a main air supply port (15).

3. The parking brake system (100) of a railway vehicle as claimed in claim 1, wherein the air flow cut off valves (7) includes two chambers separated by a flexible diaphragm (13).

4. The parking brake system (100) of a railway vehicle as claimed in claim 3, wherein each chamber is connected to a common air supply port.

5. The parking brake system (100) of a railway vehicle as claimed in claim 4, wherein each chamber includes a separate port to connect the flexible parking brake hose (8).

6. The parking brake system (100) of a railway vehicle as claimed in claim 2, wherein the choke hole (12) in the flexible diaphragm (13) allows sufficient air to pass to the failed brake hose to give an audible indication of leakage in the brake hose.

7. The parking brake system (100) of a railway vehicle as claimed in claim 1, wherein the two flexible parking brake hose (8) connects the parking brake line stainless steel pipes with the TBU (9) to maintain a spring actuated parking brakes in release condition while the railway vehicle is in operation.

8. The parking brake system (100) of a railway vehicle as claimed in claim 7, wherein a parking brake line stainless steel pipes connects the bogie (6) and a car body together.

9. The parking brake system (100) of a railway vehicle as claimed in claim 1, wherein the pressurized air from the main reservoir (1) maintains the parking brakes in released condition while the railway vehicle is in operation.

10. The parking brake system (100) of a railway vehicle as claimed in claim 9, wherein the pressurized air from the main reservoir (1) passes through the two flexible parking brake hose (8) fitted between the car body and the bogie (6) and through the two flexible parking brake hose (8) fitted between the bogie (6) and the TBU (9).

11. The parking brake system (100) of a railway vehicle as claimed in claim 1, wherein the BCU (2) receives electric brake signal from an electronic brake control unit (EBCU).

12. The parking brake system (100) of a railway vehicle as claimed in claim 1, wherein the BCU (2) transforms the received electric brake signal from the EBCU into pressure and deliver the pressure to the brake cylinders via double check valve (4).

13. The parking brake system (100) of a railway vehicle as claimed in claim 1, wherein the PBMV (3) connects the main reservoir (1) and the parking brake cylinder when the parking brake is released.

14. The parking brake system (100) of a railway vehicle as claimed in claim 1, wherein the PBMV (3) block the main reservoir (1) line and vent the parking brake cylinder when the parking brake is applied.

16. The parking brake system (100) of a railway vehicle as claimed in claim 1, wherein the double check valve (4) maintains the combined pressure and spring force within the spring force pressure when the parking brake is applied.

17. The parking brake system (100) of a railway vehicle as claimed in claim 1, wherein the parking brake cock (5) includes a venting port and works on negative logic.

18. The parking brake system (100) of a railway vehicle as claimed in claim 1, wherein the remote release handle (10) activates emergency release gear on the brake cylinder and spring actuator to release the spring and manually releases the parking brake.