FIELD OF INVENTION

The invention relates to a Bogie Mounted Brake System (hereinafter referred as BMBS), to be used generally in railway freight wagons, and the method of its operation thereof. Said BMBS unit includes two Brake Beams, a Brake Cylinder with an inbuilt Slack Adjusters, two Bell Crank levers, two Push Rods and 4 nos. of Brake Heads; wherein said braking system is associated with several advantageous features, like easy handling, compact in size, easy in maintenance, more reliable due to less number of components therein, robust & strong towards longer operational life, and suitable to be used in heavy axle load wagon. The Bogie mounted Brake System is mounted on bogie side with beams sliding inside the pockets located inside lower portion of the side frames, to provide a device with a significantly lower weight and simpler design with better braking characteristics. The most preferred embodiment of said BMBS unit and the method of its operation are best provisioned for effective handling of 25 ton axle load.

BACKGROUND AND PRIOR ARTS:

Modern brake systems for railway vehicles comprise components which are to be controlled pneumatically and/or hydraulically as well as electronically. In the Standard-gauge railway domain, pneumatic systems are usually used, by means of which the braking devices of the railway vehicle as well as additional auxiliary units, such as the spring loaded brakes, the wheel flange lubrication system, the cleaning block, the sanding device, etc., are controlled. For this purpose, the railway vehicle has a compressed-air generating device which, as a rule, directly feeds a main air reservoir line as well as, by way of a train brake valve, a main air line. The braking device of the train vehicle and the auxiliary units are in this case supplied with compressed air by the main air reservoir line. For this purpose, auxiliary units of the train formation, such as door opening devices, are also controlled by the main air reservoir line. The main air line supplied by way of the train brake valve is used for controlling the individual car brakes of a train formation and can also be utilized as an additional control for the brake systems of the train vehicle.
However, such a construction requires extensive pneumatic installations in the train formation and particularly between the engineer's cab and the bogies of the train vehicle. As a result, the freedom of construction is limited when such railway vehicles are further developed because considerable space is required. Other disadvantages are the weight of these installations and the expenditures required particularly for the mounting. Such a pneumatic control unit is known, for example, from European Patent Document EP O 855319 A2.
From German Patent Documents DE-AS 21 05 564 and DE 28 01 778 A1 by the same applicant, for example, electro-pneumatic brakes for railway vehicles are known.
In U.S. Patent Documents U.S. Pat. No. 5,503,469 and U.S. Pat. No. 5,538,331, electro-pneumatic brake systems are also described in which central computers are used as the control unit in order to simplify the system and save components, such as micro switches. In addition, the central computer permits a linking of different electro-pneumatic vehicle systems by means of a corresponding programming.
From German Patent Document DE 28 40 262 C2, it is finally known to process current operating data in a central computer and take data into account when controlling the braking devices.
German Patent Document DE 38 33 922 A1 as well as European Patent Document EP 0363 827 A2 by the same applicant disclose a brake system for rail borne bogie vehicles which has a hydraulic pressure supply unit in each of the bogies.
German Patent Document DE 4322 71.6 A1 discloses a frame for commercial vehicles which is constructed of a front-axle partial frame, a centre partial frame and a rear-axle partial frame. The front-axle partial frame and the rear-axle partial frame consist of side member segments connected with cross members.
German Patent Document DE 39 40 250 A1 discloses pressure medium reservoirs arranged in a motor vehicle or in a passenger car in support member profiles.
CN201834026U provides a foundation brake device of a two-axle bogie, which comprises brake heads, brake blocks, first brake levers, second brake levers, brake pull rods and brake beams. The brake heads and the brake blocks are respectively mounted on two sides of each wheel, each two brake heads positioned on the same side of each axle are connected with each other by one brake beam, the brake beams are respectively connected with lower ends of the first brake levers and the second brake levers, each first brake lever is correspondingly connected with the middle of the second brake lever which is positioned at the same end, with the first brake lever, of the corresponding axle by the corresponding brake pull rod bridged above the axle, and one end, which is close to a beam, of each brake pull rod is hinged with a rotary rod on the upper side of the beam.
Though there are ample patent/non-parent literature is available regarding brake system to be applied with railway bogie, there is further scope of improvements in their construction and operations thereof.
In continuation to the tradition of launching latest and technologically advanced products for Indian Railways, the instant invention is intended to provide Bogie Mounted Brake System for freight cars designated as BMBS.
The developed BMBS unit is compatible with all type of railway wagons, currently in application, including BOBRN, BOXN, BOXNHL, BCN, BCNA, etc.
The present invention is intended to resolve technical problems relating conventional bogie mounted brake system, which particularly relating to the area of the braking force transferred directly onto the wheels without the application of complex and heavy lever systems with low efficiency of transfer of the force onto the wheels, particularly for use in freight wagons.
The prime object of the present invention is to provide an integrated bogie mounted brake system to be used in railway freight Wagons, which comprises two brake beams, a brake cylinder with inbuilt slack adjuster, two Bell Crank levers, two push rods and four brake heads.
Another object of the present invention is to provide a method of operation of the integrated bogie mounted brake system.
Another object of the present invention is to provide such an integrated bogie mounted brake system, wherein the braking is performed by introducing pressurized air into the relevant brake cylinder chamber, and wherein through a system of levers and slack adjusters, the created force in the brake cylinder is intensified and transferred directly onto the wheels of the bogie.
Another object of the present invention is to provide such an integrated bogie mounted brake system, wherein said braking system and its method of operation thereof comprises following non-obvious and unique constructional/functional features:
• The brake cylinder compresses inwards during brake actuation and expands outwards during the brake release.
• The slack adjustment also takes place inwards, hence initial cylinder is fully expanded and contracts with slack adjustment taking place.
• After complete utilization of slack, cylinder can be reset to initial position by rotation of outer tube clockwise in order to expand the Brake Cylinder.
Another object of the present invention is to provide such an integrated bogie mounted brake system, wherein it comprises an Escorts Ratio Valve (ERV), wherein the most preferred embodiment of said ERV is schematically shown in Figure 12 herein below.

SHORT DETAILS OF THE DRAWINGS:
Schematic drawings referred herein for describing and illustrating the instant invention, are mentioned herein as under:
Figure 1: Sectional View of Brake Cylinder-11 Inch with Hand Brake Cable
Figure 2: Escorts Ratio Valve (ERV)
Figure 3: Brake Application condition in BMBS
Figure: Force Transfer from Brake Cylinder to Wheels
Figure 5: Brake Release condition in BMBS
Figure 6: Sequential detail of general Arrangement of Bogie Mounted Brake System (BMBS)
Figure 7: General Arrangement of Bogie Mounted Brake System (BMBS)
Figure 8: Primary Brake Beam Assy.
Figure 9: Secondary Brake Beam Assy.
Figure 10: Brake Cylinder – 11 Inch with hand brake arrangement
Figure 11: Brake Cylinder – 11 Inch without hand brake arrangement
Figure 12: Sectional View of Escorts Ratio Valve (ERV)

DESCRIPTION OF THE PRESENT INVENTION:
The invention in general relates to the bogie mounted brake system to be used in railway freight Wagons. Braking of railway freight Wagons are done by introducing pressurized air into the relevant brake cylinder chamber. Through a system of levers and slack adjusters, the created force in the brake cylinder is intensified and transferred directly onto the wheels of the bogie.
An integrated bogie mounted brake system comprising two brake beams, a brake cylinder with inbuilt slack adjuster, two Bell Crank levers, two push rods and four brake heads.
The technical problem that is resolved with this invention is mainly the area of the braking force transferred directly onto the wheels without the application of complex and heavy lever systems with low efficiency of transfer of the force onto the wheels, particularly for use in freight wagons.
In continuation to the tradition of launching latest and technologically advanced products for Indian Railways we have introduced Bogie Mounted Brake System for freight cars designated as BMBS.
The developed BMBS unit is compatible with all type of railway wagons, currently in application, including BOBRN, BOXN, BOXNHL, BCN, BCNA, etc.
Principle Of Operation (Ref: Figure 1)
BMBS consist of a Brake Cylinder as an actuation device, different from the traditional actuators. During the brake actuation, the Brake Cylinder compresses inwards and during the brake release, the Brake Cylinder expands.
Brake Application
Air enters into the Brake Cylinder from the Escorts Ratio Valve (ERV). Compressed air is admitted through Inlet port in Brake Cylinder between piston and cylinder body. The compressed air forces the piston and allows the Adjuster Spindle assembly to move inside.
The Adjuster Spindle assembly moves inward against the main compression spring of Brake Cylinder. The cross head can move in a curved path to suit the brake rigging.
The Piston indicator, painted in red colour, is attached with the piston rod which shows the piston stroke.
In case of Brake Cylinder with Hand Brake provision, all internal components and brake application procedure remain similar to that of Brake Cylinder without hand brake. The piston rods which are coming out of back cover are attached to the pull lever assembly. Pull lever assembly is hinged to back cover. When the wire rope is pulled (using hand brake wheel), the piston movement initiates brake application.
Brake Release
During release mode, the air is released through Pneumatic Valve. This decreases the brake cylinder pressure and as a result the piston moves back. This motion is transmitted to the Adjuster Spindle assembly also and as a result centre to centre distance of brake cylinder increases.
The Piston Indicator also moves in and its red colour disappears showing brake release condition.
Operating principle of the instant Braking System:
The brake system provided on the wagons with BMBS is single / twin pipe graduated release system with automatic two stage braking. Its operating principle is as follows:
The wagons are, provided with ERV/APM device to cater for higher brake power in loaded condition instead of the conventional manual empty load device. With the provision of this, brake cylinder pressure of 2.2 ± 0.25 kg/cm2 is obtained in empty condition and 3.8 ± 0.1 kg/cm2 is obtained in the loaded condition.
The mechanism gets actuated at a pre-determined change over weight of the wagon and changes the pressure going to the brake cylinder from 2.2 ± 0.25 kg/cm2 to 3.8 ± 0.1 kg/cm2 in case of changeover from empty to loaded and vice versa.
For application of brake, air pressure in the brake pipe is reduced by venting it to the atmosphere from driver's brake valve in the locomotive. The reduction of the brake pipe pressure, positions the pneumatic valve in such a way that the auxiliary reservoir is connected to the brake cylinder through the ERV/APM device and thereby applying the brake. The pneumatic valve gives an output pressure of 3.8 kg/cm2 for the brake cylinder which is routed through the ERV/APM device. Based on the position of sensor arm of ERV/APM device, it gives an output of 2.2 ± 0.25 kg/cm2 for empty position braking and an output of 3.8 ± 0.1 kg/cm2 for loaded position braking in the wagon.
During full service brake application, a reduction of Brake Pipe Pressure ranging from 1.3 to 1.6 kg/cm2 takes place and a maximum brake cylinder pressure of 3.8 ± 0.1 kg/cm2 in loaded condition and 2.2 ± 0.25 kg/cm2 in empty condition is achieved. Any further reduction of brake pipe pressure has no effect on the brake cylinder pressure.
During emergency brake application, the brake pipe is vented to atmosphere very quickly; as a result the pneumatic valve acquires the full application position also at a faster rate. This result in quicker built up of brake cylinder pressure but the maximum brake cylinder pressure will be the same as that obtained during a full service brake application.
For release of brakes, air pressure in the brake pipe is increased through driver's brake valve. The increase in the brake pipe pressure results in exhausting the brake cylinder pressure through the Pneumatic valve. The decrease in the brake cylinder pressure corresponds to the increase in the brake pipe pressure. When the brake pipe pressure reaches 5 kg/cm2, the brake cylinder pressure exhausts completely and the brakes are completely released.
Different Parts Of BMBS
Brake Beams
Brake beams are integral part of BMBS system. There are two kinds of brake beams viz. Primary & Secondary which transmits brake force.

Brake Cylinder 11” (With Hand Brake & Without Hand Brake)
Brake cylinder (With Hand Brake) and Brake Cylinder (Without Hand Brake) are similar in construction internally. Pull lever assembly and cable mounting bracket are externally added in case of Brake cylinder with hand brake. Brake cylinder also has in built double acting slack adjuster.
Stroke length at pressure 2.2±0.25 kg/cm2 on Empty condition is 55±10mm. The integral double acting slack adjuster of the brake cylinder maintains a constant piston stroke resulting in uniform brake performance even as the brake shoes and wheels wear. The double acting slack adjuster has a total make-up capacity of 500mm, which will compensate for total combination of shoe wear, wheel wear and clearance.
Escorts Ratio Valve (ERV)
Ideally the ERV Sensor Arm (1) remains close to the housing in the initial/release condition (Fig 12). Both Movement & Ratio Piston (2, 3) remain on the left side against spring (4, 5) force.
In the empty position, the Movement Piston and Ratio Piston (2, 3) shifts towards the right side as air pressure is more than spring (4, 5) force. After crossing the transition position, air enter into the reservoir and empty condition is achieved delivering 2.2kg/cm2 output.
In the Changeover position, the Movement Piston and Ratio Piston (2, 3) shifts towards the right side as air pressure is more than spring (4, 5) force. After reaching the transition position, air enters into the reservoir and transition condition is achieved. As pressure increases in the Distributor Valve port, it equalizes the volume with the brake cylinder by resetting the ratio piston.
In Loaded Position, Movement and Ratio piston (2, 3) moves towards the right side until sensor arm (1) touches the side frame. Hence movement Piston (2) stops before Transition position resulting in output pressure of 3.8 kg/ cm2.
ADVANTAGES OF BOGIE MOUNTED BRAKE SYSTEM (BMBS)
• Easy to handle
• Compact in size
• Involves less no. of parts thus requires less maintenance
• More reliable due to less no. of parts
• Robust and strong giving a better life
• Suitable for use in heavy axle load wagon.
Although the invention has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternate embodiments of the invention, will become apparent to persons skilled in the art upon reference to the description of the invention. It is therefore contemplated that such modifications can be made without departing from the spirit or scope of the present invention as defined.

WE CLAIM

1. Bogie Mounted Brake System and the method of its operation thereof, wherein said Braking System mainly comprising of two Brake Beams, a Brake Cylinder with an inbuilt Slack Adjuster, two Bell Crank levers, two Push Rods and 4 nos. of Brake Heads; wherein said Brake System is provisioned to be mounted on bogie with beams sliding inside the pockets located inside lower portion of the side frames, and said Brake System is characterized in several advantageous features, as under:
• to provide a device with a significantly lower weight and simpler design with better braking characteristics;
• easy handling, compact in size and easy in maintenance;
• more reliable due to less number of components therein;
• robust & strong towards longer operational life, and suitable to be used in heavy axle load wagon.
2. Bogie Mounted Brake System, as claimed in claim 1, wherein said Brake System is characterized in its brake cylinder, which compresses inwards during brake actuation and expands outwards during the brake release.
3. Bogie Mounted Brake System, as claimed in claim 1, wherein the slack adjustment in the said Brake System takes place inwards, hence initial cylinder is fully expanded and contracts with the said slack adjustment thereof.
4. Bogie Mounted Brake System, as claimed in claim 1, wherein after complete utilization of slack, Cylinder can be reset to initial position by rotation of outer tube clockwise in order to expand the Brake Cylinder.
5. Bogie Mounted Brake System, as claimed in claim 1, wherein said Brake System is characterized in at least one of the followings:
• The brake cylinder compresses inwards during brake actuation and expands outwards during the brake release;
• The slack adjustment also takes place inwards, hence initial cylinder is fully expanded and contracts with slack adjustment taking place.
• After complete utilization of slack, Cylinder can be reset to initial position by rotation of outer tube clockwise in order to expand the Brake Cylinder.
6. Bogie Mounted Brake System, as claimed in claim 1, wherein said Brake System comprises an Escorts Ratio Valve (ERV), the preferred embodiment of said ERV is characterized in the followings:
• Ideally the ERV Sensor Arm (1) remains close to the housing in the initial/release condition (Fig 12). Both Movement & Ratio Piston (2, 3) remain on the left side against spring (4, 5) force.
• In the empty position, the Movement Piston and Ratio Piston (2, 3) shifts towards the right side as air pressure is more than spring (4, 5) force. After crossing the transition position, air enter into the reservoir and empty condition is achieved delivering 2.2kg/cm2 output.
• In the Changeover position, the Movement Piston and Ratio Piston (2, 3) shifts towards the right side as air pressure is more than spring (4, 5) force. After reaching the transition position, air enters into the reservoir and transition condition is achieved. As pressure increases in the DV port, it equalizes the volume with the brake cylinder by resetting the ratio piston.
• In Loaded Position, Movement and Ratio piston (2, 3) moves towards the right side until sensor arm (1) touches the side frame. Hence movement Piston (2) stops before Transition position resulting in output pressure of 3.8 kg/ cm2
7. Bogie Mounted Brake System and the method of its operation thereof, as claimed in claim 1, wherein said Brake System is characterized in following constructional/functional aspects:
• Brake beams as integral part of said BMBS system, wherein said brake beams are of two kinds, beams viz. Primary & Secondary which transmits brake force;
• Brake cylinder (With Hand Brake) and Brake Cylinder (Without Hand Brake) are similar in construction internally;
• Pull lever assembly and cable mounting bracket are externally added in case of Brake cylinder with hand brake;
• Brake cylinder also has in built double acting slack adjuster;
• Stroke length at pressure 2.2±0.25 kg/cm2 on Empty condition is 55±10mm;
• The integral double acting slack adjuster of the brake cylinder maintains a constant piston stroke resulting in uniform brake performance even as the brake shoes and wheels wear;
• The double acting slack adjuster has a total make-up capacity of 500mm, which will compensate for total combination of shoe wear, wheel wear and clearance.

8. Bogie Mounted Brake System and the method of its operation thereof, as claimed in claim 1, wherein the said Brake System includes:
• Brake Application:
Air enters into the Brake Cylinder from the Escorts Ratio Valve (ERV). Compressed air is admitted through Inlet port in Brake Cylinder between piston and cylinder body. The compressed air forces the piston and allows the Adjuster Spindle assembly to move inside.
The Adjuster Spindle assembly moves inward against the main compression spring of Brake Cylinder. The cross head can move in a curved path to suit the brake rigging.
The Piston indicator, painted in red colour, is attached with the piston rod which shows the piston stroke.
In case of Brake Cylinder with Hand Brake provision, all internal components and brake application procedure remain similar to that of Brake Cylinder without hand brake. The piston rods which are coming out of back cover are attached to the pull lever assembly. Pull lever assembly is hinged to back cover. When the wire rope is pulled (using hand brake wheel), the piston movement initiates brake application.
• Brake Release:
During release mode, the air is released through Pneumatic Valve. This decreases the brake cylinder pressure and as a result the piston moves back. This motion is transmitted to the Adjuster Spindle assembly also and as a result centre to centre distance of brake cylinder increases.
The Piston Indicator also moves in and its red colour disappears showing brake release condition.
9. Method of operating the Bogie Mounted Brake System (BMBS), as claimed in any of the preceding claims 1-8, wherein said method includes and characterizes in the followings:
• The BMBS unit therein comprises of two major structural items, named as Primary Beam and Secondary Beam, wherein said BMBS unit consists of Push Rods and Bell crank levers;
• The actuation of rigging arrangement is done with an 11 inch brake cylinder having inbuilt double acting slack adjuster;
• The brake cylinder is mounted transversely to the track and the piston of the cylinder acting opposite to that of the other conventional bogie mounted brake system existing which ensures a better braking efficiency;
• The load sensing device for automatic changeover of brake cylinder pressure;
• Said BMBS system is capable of fitment into any standard CASNUB bogie and used with K Type 58 mm Composite brake block;
• The Automatic Pressure Modulation Device is able to convert pressure from 3.8±0.1 Kg/cm2 to 2.2±0.25 Kg/cm2 depending on load situation;
• Said BMBS system is also provided with a hand brake mechanism;
• The brake beams are robust, strong and well tested in static as well as dynamic mode.
10. Bogie Mounted Brake System and the method of its operation thereof, as claimed in claim 1, wherein in an exemplary scenario of operating the said Braking System includes the followings:
• The wagons are provided with ERV/APM device to cater for higher brake power in loaded condition instead of the conventional manual empty load device. With the provision of this, brake cylinder pressure of 2.2 ± 0.25 kg/cm2 is obtained in empty condition and 3.8 ± 0.1 kg/cm2 is obtained in the loaded condition.
• The mechanism gets actuated at a pre-determined change over weight of the wagon and changes the pressure going to the brake cylinder from 2.2 ± 0.25 kg/cm2 to 3.8 ± 0.1 kg/cm2 in case of changeover from empty to loaded and vice versa.
• For application of brake, air pressure in the brake pipe is reduced by venting it to the atmosphere from driver's brake valve in the locomotive. The reduction of the brake pipe pressure, positions the pneumatic valve in such a way that the auxiliary reservoir is connected to the brake cylinder through the ERV/APM device and thereby applying the brake.
• The pneumatic valve gives an output pressure of 3.8 kg/cm2 for the brake cylinder which is routed through the ERV/APM device. Based on the position of sensor arm of ERV/APM device, it gives an output of 2.2 ± 0.25 kg/cm2 for empty position braking and an output of 3.8 ± 0.1 kg/cm2 for loaded position braking in the wagon.
• During full service brake application, a reduction of Brake Pipe Pressure ranging from1.3 to 1.6 kg/cm2 takes place and a maximum brake cylinder pressure of 3.8 ± 0.Kg/cm2 in loaded condition and 2.2 ± 0.25 kg/cm2 in empty condition is achieved. Any further reduction of brake pipe pressure has no effect on the brake cylinder pressure.
• During emergency brake application, the brake pipe is vented to atmosphere very quickly; as a result the pneumatic valve acquires the full application position also at a faster rate. This result in quicker built up of brake cylinder pressure but the maximum brake cylinder pressure will be the same as that obtained during a full service brake application.