FIELD OF INVENTION
This invention relates to an air brake system for use on rolling stocks. In particular, this invention relates to an air brake system, which incorporates a mechanism for preventing the brake binding caused by the malfunctioning of the distributor valve of the air brake system
BACKGROUND OF THE INVENTION
The rolling stock of railways have air brake system in their locomotives. The air brake system presently deployed have driver's brake valve provided in the locomotive; a distributor valve connected to driver's brake valve through a brake pipe line, a brake cylinder connected to the distributor valve by brake cylinder pipeline and an auxiliary air reservoir. The piston of the brake cylinder is connected to the brake shoes through brake rigging so that when piston moves forward the brake shoes get applied on to the wheels and when piston moves backward, the brake shoes get detached from the wheels. For applying brakes, the train driver moves the brake valve handle to the application position, which reduces pressure in the brake pipe from the normal working pressure of 5kg/cm2 to about 3.4kg/cm2. The reduction in brake pipe pressure, is sensed by the distributor valve and it connects the auxiliary air reservoir to the brake cylinder The brake cylinder, on receiving air from the air reservoir, pushes the piston outward thereby pushing the brake shoes to the forward direction through a mechanical linkage, resulting into braking action.
For releasing of brakes, the driver again moves the brake valve handle to release & running position. This restores the brake pipe pressure to normal working pressure Such an increase in pressure is sensed by the distributor valve, which disconnects the air reservoir passage with brake cylinder and allows the venting of the
brake cylinder air through the distributor valve thereby detaching the brake shoes from the wheels.
A disadvantage associated with the known construction of the air brake system is that in some cases, due to the malfunctioning of distributor valve, the brake cylinder is not able to vent out completely within the specified limit, which leads to partial or total brake binding i.e. brake shoes on that particular rolling stock do not get detached
from the wheels resulting in constant rubbing of the brake shoes with the wheels.
Such a brake binding results in train detention requiring either enroute detachment or isolation of brakes of the defective rolling stock. Further brake binding can result in loss of brake power and may lead to damaged wheels and may cause rail fracture.
OBJECTS OF PRESENT INVENTION
An object of this invention is to provide an air brake system with an improved construction for use on rolling stocks.
Another object of this invention is to provide an air brake system for use in rolling stock which obviates the disadvantage of brake binding caused by the malfunctioning of distributor valve in the air brake system known in the art.
Still another object of this invention is to provide an air brake system, which does not disturb the functioning of the air brake system already employed in the rolling stock but provides an additional mechanism without requiring any changes in the construction of the air brake system and can also be retrofitted on the existing air brakes. This
mechanism comes into function only when distributor valve malfunctions and is not able to vent out completely the air from the brake cylinder.
Yet another object of this invention is to provide an air brake system, which is efficient.
STATEMENT OF INVENTION
This invention provides an air brake system for use on rolling stocks. The air brake system provided herein has an improved construction over the air brake system known in the art. It overcomes a major drawback experienced in the existing air brake system. The drawback is that in the existing air brake system, even when driver's brake vlave(l) is brought to release and running position by the train driver, due to the malfunctioning of distibutor valve(2), the air inside the brake cylinder is either not vented out or is partially vented out, with the result that that the brake shoes are not properly detached from the wheels. This phenomenon is referred to herein as 'brake binding' causes constant rubbing of brake shoes with the wheels resulting in hot spots, damaged wheels/rail fracture. These in turn cause train detention, enroute detachment/isolation of brakes, and loss in braking power. The air brake system in the present invention, incorporates, in addition to the existing configuration air brake system, an additional device referred to either as 'brake binding eliminator' or as 'brake release cylinder valve', and hereinafter would be referred to by the latter nomenclature. This device can be fitted as an 'add-on' device, on to new rolling stocks as well as to the existing rolling stocks, by the same additional fitment shown in fig.3, without interfering, in any way with the existing construction of air brake system of the existing rolling stocks. This device also does not interfere with the working of the existing air brake system
and comes into function only when the distributor valve does not function properly
The brake cylinder release valve (5) shown in detail in fig. 2, is basically a three port valve, comprising of three chambers (13,14,15). The upper chamber(13) incorporates mechanism for adjusting the spring force, which in turn adjusts the brake pipe pressure to a pre-set value which is generally the brake pipe pressure at which the brakes should completely release, which is generally set at 4.8kgf/cm2 . The upper diaphragm plate (19) gets lifted up when the signal pressure acting from the lower side of the diaphragm plate is more than the spring force adjusted with the adjusting screw (16). This results to increase in pressure on the upper side of the lower diaphragm plate(36) which pushes the piston down and IN-port and OUT-port get connected, venting out air from the brake cylinder to atmosphere and thereby brake shoes(8) get detached from wheels(9) and thus brake binding is prevented.
DESCRIPTION OF FIGURES
The air brake system of the present invention will now be illustrated with the help of accompanying drawings, which are intended to illustrate an embodiment of the present invention and are not intended to be taken restrictively to imply any limitation on the scope of the present invention. In the accompanying drawings:-
Fig 1 - shows the lay-out of the air brake system with Brake Binding eliminator or Brake cylinder release valve.
Fig 2 - shows the construction of brake binding eliminator,
referred to hereinafter as 'Brake cylinder release valve'
Fig.3:- shows the construction of fitment/retro-fitment of Brake
Cylinder release valve on new/existing rolling stock
Fig.4:- shows the working of Brake release cylinder valve
DESCRIPTION OF INVENTION DRAWINGS
Referring to Fig. 1, the air brake system of the present invention comprises driver's brake valve(1), distributor valve(2), brake cylinder(3), an auxiliary air reservoir(4) connected to distributor valve(2) by air reservoir pipeline(58) and brake cylinder release valve (5) and fitment/retro-fitment (12) (shown within dotted lines in Fig. 1) for fitting the brake cylinder release valve(5) on new or existing rolling stocks. The driver's brake valve(l) is provided in the locomotive, which can be moved by the train driver to the application position when he wants to apply brakes to the train and can be moved to normal release & running position when the train driver wants to release the brakes or when the train is running in normal course. The distributor valve(2) is connected to the drivers brake valve(l) through brake pipeline(6). The brake cylinder (3) is adapted to be connected to the distributor valve (2) by brake cylinder line (7) as well as to the brake release cylinder valve (5) by a hose (57) which a part of the fitrnent/retro-fitment (12) shown in detail in fig.3. The brake cylinder release valve (5) is also connected to the driver's brake valve (l) by a parallel brake pipeline (ll) The forward motion of piston (l0) of brake cylinder causes application of brake shoes (8) on to the wheels (9) resulting in braking action whereas the backward motion of piston causes detachment of brake shoes resulting into release of brakes When the driver
moves the driver's brake valve (l) into application position, it results into reduction in brake pipe pressure. This reduction in pressure is sensed by distributor valve, which connects the air reservoirs causing forward motion of piston. When the driver moves the driver's brake valve handle (1) to normal position, it restores the normal pressure in brake pipe. This increase in pressure is sensed by the distributor valve which disconnects the air reservoir and connects the brake cylinder to atmosphere thereby venting out the air causing backward motion of piston. In case of malfunctioning of distributor valve (2), the brake cylinder release valve (5) comes into function, which senses the rise in brake pipe pressure and vents out air from brake cylinder through OUT-port brake cylinder release valve (5) to the atmosphere, thereby eliminating the chance of brake binding action that may occur due to partial venting out or non venting of air due to the malfunctioning of the distributor valve (2).
Fig.2, shows the detailed construction of the brake cylinder release valve(5) which is basically a three port valve, which continuously monitors the brake pipe pressure Three ports are signal port (50), IN-port((34) and OUT-port(35) which is connected to the atmosphere. As soon as the brake pipe pressure reaches a pre-set value at which the brake get released, it connects (see Fig4) the IN-port (34) to the OUT-port (35) thereby venting out the air to atmosphere. The brake cylinder release valve (5) broadly comprises of three chambers (13,14,15) namely the upper chamber(13), the middle chamber(14) and the lower chamber(15). The upper chamber (13) has a bell-shaped structure and is separated from middle chamber (14) by upper diaphragm (23). The middle chamber (14) and lower chamber (15) are separated by lower diaphragm (24). All the three chambers are secured together with 6 number of screws like the two screws (49,49) shown in fig 2(b). The signal port (50) is connected to the brake pipe and in turn to the driver' brake valve on the locomotive. The brake pipe pressure acts as the signal pressure to the brake cylinder release valve (5).
The upper chamber (13) is provided with adjusting screws (16), Locknut (l7), adjustment spring (18), upper diaphragm plate (19) and steel ball (20). The adjusting screw (16) is a threaded screw which is screwed into the threading provided on the interior side of the upper part of the upper housing (13). It passes through the spring seat (21) which rests on the adjustment spring (18). The steel ball (20) rests in the groove provided on the upper diaphragm plate (19) which is fixed on the upper diaphragm (23). The adjusting screw (16) is adjusted so as to exert the required force on the steel ball (20) and upper diaphragm plate (19) and is then locked in a position with locknut (17). A bleeding port filter (51) screwed inside the threading provided in the upper chamber (13) prevents the dust from entering into the assembly. The middle chamber (14) has a groove to hold an 'O' ring (25), which seals the signal pressure and prevents it from entering into the upper chamber (13). The 'IN port'(34) is connected to the brake cylinder through hose (57) and the third port namely 'OUT port' (35) is connected to the atmosphere
The lower chamber (15) houses piston (26), 'O' ring (27), valve seat (28) fixed to the fixed to the valve head (32), support spring (29), 'O" ring (30), Flat sealing ring (31) and locking screw (33). The 'O' ring (27) prevents the brake pipe pressure from going to middle housing (14). The piston (26) provided inside an internal bore in the lower housing (25), 'O' ring (30) is fixed into the groove provided in the valve head (32). The valve head (32) is placed on the support spring (29) The support spring (29) is inserted into a bore provided in the locking screw (33) whereas flat sealing ring (31) is inserted into a groove provided in the locking screw (33). The entire assembly is screwed to the bottom of the lower housing (l5).
Referring to Fig 3, the brake cylinder release valve is fitted on to the flange(37), which is fitted on to the Brake pipe pressure adapter(38) by six number of hex-head screws like the two screws(39,40) and six number spring washers like the two washers(41,42). Filter(43) and choke (44) are screwed to the BP adapter(38), which is mounted on the common pipe bracket fitted on to the rolling stock, through two hex-head screws 12x35 like the screw(45) and spring washer B 12(46). Duplex reducing nippleRl/2"XRl/4 " (47) is fixed on the "IN-port valve" of the Brake cylinder release valve(5).Brake cylinder release line(7), which is in the form of pneumatic tool hoseRl/2"X1000, is screwed into the duplex reducing nipple(47) The other end of brake cylinder release hose(7) is screwed on to the Brake cylinder adapter(48), which is mounted on BC Flange which inturn is fitted on the brake cylinder port of the common pipe bracket fitted on to the rolling stocks, by two hex head bolt M12X50 and spring washer B 12
Referring to Fig.4, which shows the working of the brake cylinder release valve(5), the spring force on the upper diaphragm plate(19) is adjusted with the help of adjusting serew ( 16), as result of which the signal pressure gets adjusted to a specified value which is generally around 4.8kgf/cm2 .This spring force acts over the upper side of the upper diaphragm plate(19), signal pressure is fed to the signal port(50), which acts on the lower side of the upper diaphragm plate(19). When the signal pressure reaches to such a value that the force acting on the diaphragm (23) from the lower side is more than the spring force, the diaphragm plate (19) gets lifted up. As a result, the signal pressure rushes to act on the upper side of the lower diaphragm plate (36) The force thus exerted by this pressure on the lower diaphragm, is more than the spring force of the support spring (29). This pushes the piston down which displaces the sealing of the valve head (32) with housing. As a result, the IN-port and OUT-port get connected as shown in fig.4 (b) and the brake cylinder pressure gets exhausted to the atmosphere.
It is to be noted that the air brake system of the present invention is susceptible to modifications, changes and adaptations by those skilled in the art. Such variant embodiments incorporating the concepts feature of the present invention are intended to be within the scope of the present invention which is further set forth under the following claims:

WE CLAIM
1. An air brake system for use on rolling stocks, comprising :
(a) driver's brake valve(l) connected to the distributor valve(2) by brake
pipeline(6) and also connected to the brake cylinder adapter (38) of
the ntment/retro-fitment(12) for the brake cylinder release valve(5)
by means of parallel brake pipeline(l 1),
(b) brake cylinder(3) connected to distributor valve(2) by means of
brake cylinder line(7) and also to the brake cylinder release valve (5)
by hose (57) and its piston(10) being connected to the brake
shoes(8);
(c) an auxiliary air reservoir(4) connected to distributor valve (2) by air
reservoir pipeline (58) which gets connected to the brake cylinder(3)
when distributor valve(2) senses fall in brake pipe pressure and gets
disconnected from brake cylinder when distributor valve(2) senses
increase in brake pipe pressure
(d) brake cylinder release valve (5) comprising ;
-an upper chamber(13) provided with adjustment screws(16), locknut(17), adjustment spring(18), upper diaphragm plate(19), steel ball(20), spring seat(21), bleeding port filter(51), and upper diaphragm (23) which separates the upper chamber(13) from the middle chamber(14), -middle chamber(14) having a grove to hold an 'O' ring,

-a lower chamber(15) which houses valve(22), piston(26),'O' ring(27), valve seat(28) fixed to the valve head(32), support spring(29),'O' ring(30), flat sealing ring (31), locking screw(33) with lower diaphragm(24) separating the middle chamber(14) from the lower chamber(15);
-three ports namely signal port(50), In-port(34) and OUT-port(35)
-means to secure three chambers (e) fitment/retro fitment(12) comprising, -
-flange(37) to which brake cylinder release valve is fitted which is inturn fitted to brake pipe adopter (38) by means of six screw like(39,40) and six spring washers like(41,42) -brake pipe pressure adapter(38) connected to brake cylinder release valve (5) through hose (7);
- Filter(43) and choke(44) screwed to the BP adapter(38) which inturn connected to Brake pipe port of common pipe bracket; Duplex reducing nipple(47) fixed to the IN-port of brake cylinder release valve at one end and to the brake cylinder line (7) at the other end which in turn is connected at other end to brake cylinder adapter(48) having 'O' ring (54) and mounted on brake cylinder port of common pipe by two hex-head bolts like(52) and two spring washers like(53)
2. An air brake system for use on rolling stocks as substantially described and herein illustrated.