LEVER OPERATED LOAD PROPORTIONATE VALVE FOR RAILWAY
WAGONS.
FIELD OF INVENTION
The present invention is related to a load proportionate valve employed with
brake cylinder and distributor valve on air pressure brake apparatus for a railway
vehicle and more particularly to air pressure brake apparatus embodying means
for automatically adjusting the degree of brake application in accordance with
varying load conditions of a railway freight vehicle.
BACKGROUND OF THE INVENTION
Rapid development of commercial transport by railways in recent years has been
coupled with the introduction of many types of wagon / EMU /DMU / Coach
having different specifications like speed, load bearing capacity, loaded and
unloaded running condition etc. In view of this, greater safety of the wagon / EMU
/ DMU / Coach, that is, a braking system more reliable in action and more stable
in performance than ever, is being called for.
With these heavy-duty vehicles, service brakes of the pneumatic type prevail in
which indicated braking pressure from the brake valve is conducted to the relay
valve so that compressed air corresponding to the indicated pressure is supplied
to the brake actuators via the relay valve. Since the axle-to-axle load ratio can
vary largely according to whether the vehicle is empty or loaded, the air brake
system is designed to control the indicated pressure according to the movable
load the vehicle carries, or the distance between the upper portion and lower
portion of the spring of the suspension and thereby adequately proportion the
braking forces applicable to the individual axles, avoiding any unbalanced

braking action, such as partial locking of any axle alone. In order to obtain the
indicated pressure corresponding to the payload as described above, a
conventional brake circuit as schematically shown in FIG. 1 (I) has, between the
brake valve a' and the relay valve b', a load-sensing proportion valve c' which
regulates the indicated pressure from the brake valve before the pressure is
delivered to the relay valve. Also included in the circuit is a reservoir d, a power
chamber e, and a slack adjuster f. However, installing the load-sensing
proportion valve in the line accordingly increases the amount of air retained in the
line and, inasmuch as air is a compressible medium itself, the increased air
volume in the line inevitably causes a lag in response of the brake actuators to
the instruction from the brake valve.
Typically, load adjusted air pressure brake control apparatus for railway vehicles
operating in freight service employs empty / load type brake control, which is a
two-step control wherein normal brake pressures are realized under load
conditions and a modulated brake pressure is realized under empty conditions of
vehicle loading. In modulating brake pressures under empty conditions, the
occasion of slid flat wheels, as well as rough train action due to differently loaded
cars or groups of cars is eliminated.
Because of the various load conditions of the freight cars comprising a train,
however, empty/load type brake control is not completely satisfactory, since cars
having a partial load may be underbraked or overbraked depending upon the
preselected changeover point between the empty/load setting. This situation is
even more critical with the modern lightweight cars, which have a wider range
between their gross and tare weights.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a variable load valve
device for modulating brake pressure, the amount of pressure modulation being

predicted on both the intensity of the brake application and the effective vehicle
load.
Therefore herein disclosed a lever operated load proportionate valve for the
railway wagons comprising of: a cylindrical housing with inlet and the exhaust
valve assembly connected with a lever arm; an adjusting screw; a spring loaded
diaphragm; a control spring; wherein the and the exhaust valve assembly are
seated as the system is charged to the setting of the adjusting screw.
It is a further objective that, for a given load, light brake applications are
unmodulated or modulated only slightly, with heavier brake applications being
increasingly modulated.
It is still another objective of the invention that, for a given brake application, the
degree of brake pressure modulation decreases with increasing vehicle load.
Yet another object of the invention is to provide a improvised brake cylinder
which works independently without any communication with distributor valve
which generates brake cylinder pressure.
In achieving these objectives, there is provided a load proportionate valve (LVN1)
for automatically modifying the brake cylinder pressure according to load
variation of wagon / EMU / DMU / Coach has a spring loaded lever which senses
the gap between under frame and bogie side frame of Wagon (gap reduced due
to deflection of suspension spring in loaded condition) and changes the outlet
pressure accordingly. More the load less the gap and more the outlet pressure of
LVN1.
As per another object of the present invention, the maximum outlet pressure of
the load proportionate valve (LVN1) is configured and limited upto supplied

pressure and the minimum outlet pressure is limited to the set pressure of the
valve.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects and advantages of this invention will become apparent from the
following more detailed description when taken with the accompanying drawing
in which:
FIG. 1 illustrates a view of the total assembly of the valve alongwith pipe bracket
in accordance with the present invention; and
FIG. 2 illustrates a functional view of the valve in accordance with the present
invention.
DETAILED DESCRIPTION
The present invention relates to a Load proportionate valve which is lever
operated and of the type employed with brake cylinder and distributor valve on
railway vehicles. The load proportionate valve such as herein described
automatically modifies the brake cylinder air pressure in relation to pay load of
wagon.
The said load proportionate valve (LVN1) assembled in a cylindrical housing
configured for automatically modifying the brake cylinder pressure according to
load variation of wagon / EMU / DMU / Coach has a spring loaded lever which
senses the gap between under frame and bogie side frame of Wagon (gap
reduced due to deflection of suspension spring in loaded condition) and changes
the outlet pressure accordingly.
With reference to fig 1, when the lever of the (LVN1) valve is pushed up then the
outlet pressure of LVN1 increases from lower set pressure to supply pressure of

the LVN1 valve at displacement of maximum 11mm. The LVN1 valve lever arm
has a leverage ratio 5:1 i.e. if the displacement at the effort end is 40mm then the
total displacement of LVN1 valve plunger is 8mm at load end. Maximum
displacement of LVN1 lever at effort end is 40 +/-10 mm.
The increase in the load of the wagon will create less gap in the springs. Further
the less gap in the springs create more outlet pressure of the valve LVN1. The
maximum outlet pressure of LVN1 is limited up to supplied pressure and the
minimum outlet pressure is limited to the set pressure of the valve. This can be
set to any pressure between 0.9 and 2.75 bars within a tolerance of around 3%.
The said LVN1 eliminates the load sensing device and replaces the spiral
distributor valve C3W2 with normal C3W distributor valve. This reduces the
weight of the air brake equipments of the railway vehicles and ultimately reduces
the cost of the air brake equipment.
The said valve LVN1 works independently without any communication with
distributor valve which generate brake cylinder pressure. At different wagon load
it gives different brake cylinder pressure. Since LVN1 is mounted on under frame
and not on the bogie, it is subjected to less amount of vibration. The effort end of
the lever has a spring loaded plunger, which controls the additional movement of
the bogie on which it rests. The valve is diaphragm operated and featured with
self lapping and pressure regulating device.
With reference to Fig 2, which shows the working of the said valve (LVN1),
wherein the BC pressure of higher value enters the valve at the port mark
"supply" and flows through the passage S to supply air pressure to supply
chamber C. As shown, the valve is in lap position with inlet and the exhaust valve
seated as the system is charged to the setting of the adjusting screw 45.
When the air pressure in the delivery line and in the chambers B and A has fallen
below predetermined level, the spring 47 mover the diaphragm follower 41,

exhaust valve seat 39 and the exhaust and inlet valve, and supply air from
chamber B and then through passage "r" to the delivery port. The air also flows
through choke D to a chamber A above diaphragm 40.
As the air pressure in passage 'r' and chamber A reaches the pressure for which
adjusting screw 45 is set, the air pressure and the exhaust valve spring 38 move
diaphragm 40, follower 41 and exhaust valve seat 39 downward. Inlet valve
spring 34 moves the inlet valve down on its seat 31, cutting off further flow of air
from the chamber C to chamber B.
The only adjustment for the valve LVN1 device is screw 45. Turning the screw in
raises the delivery pressure. Turning the screw out lowers the delivery pressure.
This set pressure does not change during fully open condition of lever which is
nothing but empty condition of the wagon.
During partially loaded or fully loaded condition of wagon gap between under
frame and bogie reduces, lever arm pushes the top of the inlet and exhaust valve
assembly of LVN1 device. Inlet valve housing comes down and inlet ball valve
open up from its seat 31 and chamber C and the chamber D is connected. Thus
air flows from the supply port to delivery port. Partial increase of pressure will
continue upto 8.5mm compression of pressure point of plunger then inlet
pressure (Max Brake cylinder) equalizes outlet pressure (see fig 2).
Although the foregoing description of the present invention has been shown and
described with reference to particular embodiments and applications thereof, it
has been presented for purposes of illustration and description and is not
intended to be exhaustive or to limit the invention to the particular embodiments
and applications disclosed. It will be apparent to those having ordinary skill in the
art that a number of changes, modifications, variations, or alterations to the
invention as described herein may be made, none of which depart from the spirit
or scope of the present invention. The particular embodiments and applications

were chosen and described to provide the best illustration of the principles of the
invention and its practical application to thereby enable one of ordinary skill in the
art to utilize the invention in various embodiments and with various modifications
as are suited to the particular use contemplated. All such changes, modifications,
variations, and alterations should therefore be seen as being within the scope of
the present invention as determined by the appended claims when interpreted in
accordance with the breadth to which they are fairly, legally, and equitably
entitled.

We Claim:-
1. A lever operated load proportionate valve for the railway wagons
comprising of :
a cylindrical housing with inlet and the exhaust valve assembly connected
with a lever arm;
an adjusting screw;
a spring loaded diaphragm; and
a control spring; wherein the and the inlet and exhaust valve assembly are
seated as the system is charged to the setting of the adjusting screw.
2. A lever operated load proportionate valve as claimed in claim 1 wherein
the brake cylinder pressure modification is carried out at different wagon loading.
3. A lever operated load proportionate valve as claimed in claim 2 wherein
the adjusting screw is tightened for high delivery pressure and loosened for
lowering the delivery pressure.
4. A lever operated load proportionate valve as claimed in claim 1 wherein
the lowest brake cylinder pressure is configured for the wagon in empty condition
and the highest brake cylinder pressure is configured for the wagon in loaded
condition.
5. A lever operated load proportionate valve as claimed in claim 1 wherein
the effort end of the lever has a spring loaded plunger which takes additional
movement of the bogie on which it rests.
6. A lever operated load proportionate valve as claimed in claim 1 wherein
the diaphragm is configured for self lapping and pressure regulating device.

7. A lever operated load proportionate valve as claimed in claim 1 wherein
the lever arm has a leverage ration of 5:1.
8. A lever operated load proportionate valve as claimed in claim 1 wherein
the valve is mounted on under frame and not on bogie and subjected to less
amount of vibration.
9. A lever operated load proportionate valve as claimed in claim 1 wherein
under condition that the air pressure in the delivery line and in the chambers falls
below predetermined level then the spring loaded with the diaphragm moves the
diaphragm follower with exhaust valve seat and the exhaust and inlet valve for
the supply air from chamber B and then through passage "r" to the delivery port
and further the air also flows through choke to a chamber A above diaphragm
10. A lever operated load proportionate valve as claimed in claim 1 wherein
the said valve works independent of distributor valve which generate brake
cylinder pressure and replaces the usual C3W2 special distributor valve with
C3W Distributor valve.

It is therefore an object of the present invention to provide a variable load valve
device for modulating brake pressure, the amount of pressure modulation being
predicted on both the intensity of the brake application and the effective vehicle
load.