The present disclosure relates to an automatic pressure modification (APM)
system to be employed in a wagon brake system of a train. More particularly, the
APM system including a relay valve arrangement, components of which can be
5 relatively easily accessed for replacement for altering a predefined ratio between
air pressure received and supplied by the APM system.
BACKGROUND
Trains are commonly known to employ a brake system for effective
braking in brake application operations. The brake system is a pneumatically
10 actuated brake system that further employs a number of systems for enabling
the brake application operations, based on government regulation requirements
and load conditions of each wagon of the train.
Referring to FIG. 1, there is shown a schematic of an exemplary brake
system [100]. The brake system [100] can be either of a single pipe brake system
15 [100] (Employing a single brake pipe for controlling application/ release
operation of brakes) or a twin pipe brake system (Employing a combination of
brake pipe and a feed pipe for controlling application/ release operation of
brakes). Concepts of the present disclosure will be described as applied to the
single pipe brake system [100], however it may be obvious to a person ordinarily
20 skilled in the art that the concepts of the present disclosure may further extend
to the double brake pipe system as well. For ease in reference and
understanding, the single pipe brake system [100] will be referred to as the brake
system [100] interchangeably hereinafter. The brake system [100] employs a
brake pipe [102], and a wagon brake system [104] for each wagon of the train.
25 The wagon brake system [104] is fluidly connected to the brake pipe with the use
of a hose coupling. For ease in reference and understanding, concepts of the
present disclosure will be described as applied to an arrangement of the brake
pipe [102] and a singular wagon brake system [104], for braking application
operation of a singular wagon of the train. However, it may be contemplated
3
that the concepts of the present disclosure may also extend to other wagon
brake systems [104] of the train. The brake pipe [102] is normally adapted to
receive air maintained at a defined upper brake pressure in a range of 5-6 bar
pressure, preferably at 5 bar pressure, in non-braking operating conditions when
5 a brake is not operated by a train operator. Further, the brake pipe [102] is
adapted to release air to maintain a lower brake pressure in range of 0-3.5 bar
pressure, preferably to 3.5 bar pressure, for initiating braking applications when
a brake is operated by the train operator. Moreover, the brake pipe [102] again
receives air maintained at the upper brake pressure, for example of 5 bar
10 pressure, for enabling release application when the brake is released by the train
operator. Such change in the brake pressure of air in the brake pipe [102] is
continuously sensed by the wagon brake system [104], for brake application
operation and/or brake release operation.
The wagon brake system [104] performs the brake release operation on
15 the wagon, when the brake pipe [102] receives air at the upper brake pressure.
Moreover, the wagon brake system [104] performs the braking application
operation on the wagon, when the brake pipe [102] releases air and maintains
the lower brake pressure. The wagon brake system [104] includes an auxiliary
reservoir [106], a C3W distributor valve [108], an automatic pressure
20 modification (APM) system [110], and at least one brake cylinder [112]. In the
preferred embodiment, the wagon brake system [104] employs two brake
cylinders [112].
The C3W distributor valve [108] is fluidly connected to the brake pipe
[102] and senses a brake pressure in the brake pipe [102]. The C3W distributor
25 valve [108] is adapted to output air at a first pressure in a range of 3.6 bar
pressure to 3.9 bar pressure, for example preferably at 3.8 bar pressure, as the
brake pipe [102] is maintained at the lower brake pressure. In the present
embodiment, the C3W distributor valve [108] is adapted to output air at a first
pressure of 3.8 bar pressure, as the brake pipe [102] is maintained at the lower
4
brake pressure. Therefore, the C3W distributor valve [108], upon application of
the brake by the train operator, outputs air to the brake cylinders [112], for
initiating braking application operation by the brake cylinders [112]. Also, the
C3W distributor valve [108], upon release of the brake by the train operator,
5 receives and releases air from the brake cylinders [112], to initiate brake release
operation by the brake cylinders [112]. Notably, the C3W distributor valve [108]
is fluidly connected to the auxiliary reservoir [106] for enabling receipt/ supply of
air therefrom. Further, the C3W distributor valve [108] supplies air to the brake
cylinders [112] via the automatic pressure modification (APM) system, for
10 performing the brake application operation. Moreover, the C3W distributor valve
[108] receives air from the brake cylinders [112] via the APM system [110], for
performing the brake release operation.
The APM system [110] is fluidly connected to an output of the C3W
distributor valve [108]. For performing the brake application operation, the APM
15 system [110] is adapted to receive air from the C3W distributor valve [108] at the
first pressure and supply air to the brake cylinders [112] at either of the first
pressure or a second pressure based on a load condition of the wagon of the
train. For performing the brake release operation, the APM system [110] is
adapted to release air from the brake cylinders [112] to the C3W distributor
20 valve [108]. In the preferred embodiment, the first pressure is 3.8 bar pressure.
In the preferred embodiment, the second pressure is 2.2 bar pressure.
The brake cylinders [112] are adapted to receive air from the C3W
distributor valve [108] via the APM system [110] at either of the first pressure
and the second pressure based on the load conditions of the wagon of the train.
25 The air pressure supplied to the brake cylinders [112] is directly proportional to
the magnitude of brake force applied to the wagon of the train. For example, for
performing the brake application operation in the loaded conditions of the
wagon, the brake cylinders [112] are required to apply strong impact brakes. On
the other hand, for performing the brake application operations in the empty
5
conditions of the wagon of the train, the brake cylinders [112] are required to
apply light impact brakes.
Furthermore, the APM system [110] receives air from the C3W distributor
valve [108] at the first pressure and supply air to the brake cylinders [112] at
5 either of the first pressure or the second pressure based on a load condition of
the wagon of the train. For performing the brake application operations, in the
loaded conditions of the wagon of the train, the APM system [110] is adapted to
receive air from the C3W distributor valve [108] at the first pressure (For
example 3.8 bar pressure) and supply air to the brake cylinders [112] at the first
10 pressure (For example 3.8 bar pressure). Moreover, for performing the brake
application operations, in the empty conditions of the wagon of the train, the
APM system [110] is adapted to receive air from the C3W distributor valve [108]
at the first pressure (For example 3.8 bar pressure) and supply air to the brake
cylinders [112] at the second pressure (For example 2.2 bar pressure). The APM
15 system [110] may be suitably structured and arranged to attain a predefined
ratio between the first pressure (3.8 bar pressure) and the second pressure (2.2
bar pressure).
Conventionally, the APM system [110] includes a relay valve arrangement
[116] and a normal supply valve arrangement [118]. The relay valve arrangement
20 [116] and the normal valve arrangement [118] are suitably arranged, to perform
one or more functionalities of the APM system [110]. The relay valve
arrangement [116] and the normal valve arrangement [118] are fluidly
positioned between the C3W distributor valve [108] and the brake cylinders
[112], to enable the supply of air from the C3W distributor valve [108] to the
25 brake cylinders [112] while enabling the alteration in air pressure. Notably, the
relay valve arrangement [116] is responsible for enabling the change in pressure
from the first pressure as received from the C3W distributor valve [108] to the
second pressure of air as supplied to the brake cylinders [112], to perform brake
application operations in the empty conditions of the wagon of the train. In
6
particular, the relay valve arrangement [116] is suitably structured and arranged
to include the predefined ratio between the first pressure of air as received from
the C3W distributor valve [108] and the second pressure of air as supplied to the
brake cylinders [112], to perform brake application operations in the empty
5 conditions of the wagon of the train. In certain situations, for example a change
in the type of wagon of the train, a value of the second pressure of air supplied
as supplied to the brake cylinders [112] may require to be changed to a new
second pressure, for example 2 bar pressure, while still receiving the air at the
first pressure of 3.8 bar pressure from the C3W distributor valve [108]. In such
10 situations, the predefined ratio between the second pressure of air supplied to
the brake cylinders [112] and the first pressure of air as received from the C3W
distributor valve [108] may require to be changed. For enabling such change in
the predefined ratio, the APM system [110] is required to be replaced with a new
APM system suitably designed to receive air at the first pressure (For example
15 3.8 bar pressure) from the C3W distributor valve [108], and supply the air at the
new second pressure (For example 2 bar pressure) to the brake cylinders [112].
This may be a costly and high maintenance consuming process. Furthermore, in
certain situations, the components of the relay valve arrangement [116] may
require to be accessed and serviced, and/or replace certain components of the
20 relay valve arrangement [116]. However, as the relay valve arrangement [116] is
positioned integral within a housing [114] of the APM system [110], it may be
cumbersome to access the components of the relay valve arrangement [116] of
the APM system [110]. This will add to the maintenance cost of the APM system
[110].
25 Accordingly, in light of the aforementioned drawbacks and several other
inherent in the existing arts, there is a well felt need to provide the APM system
[110], which provides for relatively easily accessible components of the relay
valve arrangement [116], thereby reducing the maintenance cost of the APM
system [110]. The APM system [110] may enable the change in predefined ratio
7
without the need of replacing the APM system [110] with the new APM system.
SUMMARY
An object of the present invention relates to an automatic pressure modification
(APM) system for receiving air at a first pressure at a distributor port and
5 selectively supplying air at one of the first pressure and a second pressure to a
brake cylinder port. The APM system includes a housing and a relay valve
arrangement. The housing includes a first end and a second end. The relay valve
arrangement is fluidly positioned between the distributor port and the brake
cylinder port within the housing. The relay valve arrangement is adapted to
10 operate in a closed position and an open position. In the open position, the relay
valve arrangement facilitates a change in air pressure from the first pressure
received at the distributor port to the second pressure supplied at the brake
cylinder port in a predefined ratio. The relay valve arrangement including a relay
piston, at least one diaphragm, a relay valve; and an end cover covering the
15 second end of the housing. The relay piston and the end cover, in combination,
define the predefined ratio between the first pressure of air received at the
distributor port and the second pressure of air supplied at the brake cylinder
port. Furthermore, the relay piston and the end cover, may be accessed through
the second end of the housing, for enabling replacement of one or more of the
20 relay piston and the end cover, for altering the predefined ratio between the first
pressure of air received at the distributor port and the second pressure of air
supplied at the brake cylinder port.
BRIEF DESCRIPTION OF DRAWINGS
The present invention, both as to its organization and manner of operation,
25 together with further objects and advantages, may best be understood by
reference to the following description, taken in connection with the
accompanying drawings. These and other details of the present invention will be
described in connection with the accompanying drawings, which are furnished
only by way of illustration and not in limitation of the invention, and in which
8
drawings:
Figure 1 shows a schematic view of a brake system [100] employed in a train,
illustrating an automatic pressure modification (APM) system, in accordance with
the concepts of the present disclosure.
5 Figures 2 shows a sectional view of the APM system [110] of FIG. 1, illustrating
various components of the APM system [110], in accordance with the concepts
of the present disclosure.
Figures 3a–3b shows a sectional view of the APM system [110] of FIG. 1,
illustrating positions of various components of the APM system [110] during
10 brake application operation conditions in a loaded condition of the wagon of the
train, in accordance with the concepts of the present disclosure.
Figures 4a–4b shows a sectional view of the APM system [110] of FIG. 1,
illustrating positions of various components of the APM system [110] during
brake release operation conditions in a loaded condition of the wagon of the
15 train, in accordance with the concepts of the present disclosure.
Figures 5a–5d shows a sectional view of the APM system [110] of FIG. 1,
illustrating positions of various components of the APM system [110] during
brake application operation conditions in an empty condition of the wagon of the
train, in accordance with the concepts of the present disclosure.
20 Figures 6a–6b shows a sectional view of the APM system [110] of FIG. 1,
illustrating positions of various components of the APM system [110] during
brake release operation conditions in an empty condition of the wagon of the
train, in accordance with the concepts of the present disclosure.
DETAILED DESCRIPTION
25 In the following description, for the purposes of explanation, various specific
details are set forth in order to provide a thorough understanding of
embodiments of the present invention. It will be apparent, however, that
embodiments of the present invention may be practiced without these specific
details. Several features described hereafter can each be used independently of
9
one another or with any combination of other features. An individual feature
may not address any of the problems discussed above or might address only one
of the problems discussed above. Some of the problems discussed above might
not be fully addressed by any of the features described herein. Example
5 embodiments of the present invention are described below, as illustrated in
various drawings in which like reference numerals refer to the same parts
throughout the different drawings.
The present disclosure relates to an automatic pressure modification (APM)
system [110] as employed in the brake system [100] of the train. The brake
10 system [100] is as shown in FIG. 1 and described in the aforementioned
disclosure. In brake application operation, the APM system [110] is employed to
receive air from a C3W distributor valve [108] at a first pressure (For example 3.8
bar pressure) and supply air to the brake cylinders [112] at either of the first
pressure (For example 3.8 bar pressure) and a second pressure (For example 2.2
15 bar pressure) based on load conditions of a wagon of the train. In particular, in
brake application operation during loaded conditions of the wagon of the
vehicle, the APM system [110] is adapted to receive air from a C3W distributor
valve [108] at the first pressure (For example 3.8 bar pressure) and supply air to
the brake cylinders [112] at the first pressure (For example 3.8 bar pressure).
20 Moreover, in brake application operation during empty conditions of the wagon
of the vehicle, the APM system [110] is adapted to receive air from the C3W
distributor valve [108] at the first pressure (For example 3.8 bar pressure) and
supply air to the brake cylinders [112] at the second pressure (For example 2.2
bar pressure). Furthermore, in brake release operations during each of the
25 loaded and empty conditions of the wagon of the train, the APM system [110] is
adapted to release air from the brake cylinders [112]. In light of this, the APM
system [110] is said to be operating in either of the following four conditions: i)
brake application operation during loaded conditions of the wagon of the train;
ii) brake release operation during loaded conditions of the wagon of the train; iii)
10
brake application operation during empty conditions of the wagon of the train;
iv) brake release operation during empty conditions of the wagon of the train. An
operation of the APM system [110] in each of these conditions will be described
in detail in the forthcoming disclosure.
5 Figure 2 illustrates the APM system [110], in accordance with the concepts of the
present disclosure. The APM system [110] includes a housing [114], a relay valve
arrangement [116], a normal supply valve arrangement [118], a control
mechanism [120], a timing reservoir [122], and an indicator [124]. The housing
[114] is adapted to cover and house one or more components of the relay valve
10 arrangement [116] and the normal supply valve arrangement [118], in order to
enable the APM system [110] to perform the required functionalities. Moreover,
the housing [114] defines a number of flow passages and chambers within itself,
to enable the functionalities associated with the APM system [110]. The housing
[114] includes a first end [114a] and a second end [114b]. The housing [114] also
15 defines a distributor port [114c] fluidly connected to the C3W distributor valve
[108], a brake cylinder port [114d] fluidly connected to the brake cylinders [112],
a timing reservoir port [114e] fluidly connected to the timing reservoir [122], and
an indicator port [114f] fluidly connected to the indicator [124].
The relay valve arrangement [116] is housed within a relay support portion
20 [114g] defined proximal to the second end [114b] of the housing [114]. The relay
valve arrangement [116] includes a relay piston [116a], at least one diaphragm
[116b, 116c], an end cover [116d], and a relay valve [116e]. The relay piston
[116a] is supported within the relay support portion [114g] defined proximal to
the second end [114b] of the housing [114], and is allowed for a linear
25 movement. In particular, the relay piston [116a] is supported at a portion of the
housing [114] at one end and is supported at the end cover [116d] at the other
end. Furthermore, the at least diaphragm [116b, 116c] includes a first diaphragm
[116b] and a second diaphragm [116c]. The first diaphragm [116b] and the
second diaphragm [116c] are positioned within the relay support portion [114g]
11
of the housing [114], between an outer periphery of the relay piston [116a] and
an inner periphery of the housing [114]. With such positioning, the relay valve
arrangement [116] defines a pilot chamber [116f] at an interface with the first
diaphragm [116b], and an equilibrating chamber [116g] at an interface with the
5 second diaphragm [116c]. The pilot chamber [116f] is in fluid communication
with the distributor port [114c] via a first flow passage [126a]. The equilibrating
chamber [116g] is in fluid communication with the brake cylinder port [114d] via
a second flow passage [126b] and a second chamber [128b] in the normal supply
valve arrangement [118]. The end cover [116d] covers the second end [114b] of
10 the housing [114], to cover various components of the relay valve arrangement
[116] of the APM system [110]. As the end cover [116d] covers the second end
[114b] of the housing [114], various components of the relay valve arrangement
[116] can be accessible by removing the end cover [116d], and accessing the
components through the second end [114b] of the housing [114]. Furthermore,
15 the relay valve [116e] is positioned in abutment with the relay piston [116a]. The
relay valve [116e] includes a transfer port [116h] and a balance port [116i]. The
transfer port [116h] is in fluid communication with the distributor port [114c] via
the first flow passage [126a], and is selectively fluidly communicated to the
equilibrating chamber [116g] of the relay valve arrangement [116]. The balance
20 port [116i] is in fluid communication with a third flow passage [126c] to be
further fluidly connected to the equilibrating chamber [116g] via the second flow
passage [126b], for keeping the relay valve [116e] balanced. Further, the relay
valve [116e] is adapted to operate in an open position and a closed position.
Notably, the open position of the relay valve [116e] corresponds to an open
25 position of the relay valve arrangement [116], and the closed position of the
relay valve [116e] corresponds to a closed position of the relay valve
arrangement [116]. For ease in reference and understanding, ‘open position’ and
‘closed position’ of the relay valve [116e] will be interchangeably referred to as
the ‘open position’ and ‘closed position’ of the relay valve arrangement [116].
12
The relay valve [116e] (or the relay valve arrangement [116]) is normally
maintained in the closed position. In the closed position, the pilot chamber
[116f] receives air at the first pressure from the distributor port [114c] via the
first flow passage [126a], and the equilibrating chamber [116g] receives air from
5 the brake cylinder port [114d] at the first pressure via the second flow passage
[126b]. Therefore, in the closed position, the air pressure in the equilibrating
chamber [116g] balances the air pressure in the pilot chamber [116f]. Therefore,
the relay piston [116a] is maintained at the equilibrium position. In such
situations, the relay valve [116e] is kept closed against a valve seat, and restricts
10 the flow of air to pass through the transfer port [116h] to the equilibrating
chamber [116g]. In nutshell, in the closed position, the relay valve arrangement
[116] is inoperative and does not effect in any way an operation of the APM
system [110].
Further, the relay valve [116e] (Or the relay valve arrangement [116]) can be
15 adjusted to the open position. For such purposes, the pilot chamber [116f]
receives air at the first pressure from the distributor port [114c] via the first flow
passage [126a], and the equilibrating chamber [116g] receives air from the brake
cylinder port [114d] at the second pressure, via the second flow passage [126b]
and the second chamber [128b] of the normal supply valve arrangement [118].
20 Therefore, in the open position, the air pressure in the equilibrating chamber
[116g] disbalances the air pressure in the pilot chamber [116f]. Therefore, the
relay piston [116a] is shifted from the equilibrium position, and is linearly moved.
In such situations, the relay valve [116e] is opened, and allows the flow of air
through the transfer port [116h] to the equilibrating chamber [116g]. Moreover,
25 volumetric difference between the pilot chamber [116f] and the equilibrating
chamber [116g] corresponds to the alteration of the air pressure between air
received at the transfer port [116h] and air supplied to the equilibrating chamber
[116g]. In particular, the relay valve [116e] receives air at the transfer port [116h]
at the first pressure from the distributor port [114c] via the first flow passage
13
[126a], and supplies air to the equilibrating chamber [116g] at the second
pressure to be supplied to the brake cylinder port [114d] via the second flow
passage [126b], and the second chamber [128b] of the normal supply valve
arrangement [118]. Notably, such alteration of the air pressure from the first
5 pressure to the second pressure is based on volumetric capacity of the
equilibrating chamber [116g]. Further, the volumetric capacity of the
equilibrating chamber [116g] is based on a dimension of the relay piston [116a]
and the end cover [116d] of the relay valve arrangement [116]. Therefore, such
alteration of the air pressure from the first pressure to the second pressure is
10 based on a dimension of the relay piston [116a] and the end cover [116d] of the
relay valve arrangement [116]. Therefore, it may be well understood that the
dimensions of the relay piston [116a] and the end cover [116d] of the relay valve
arrangement [116] define a ratio between the first pressure of air received at the
transfer port [116h] and the second pressure of air supplied to the equilibrating
15 chamber [116g]. Alternatively saying, the alteration of pressure between the first
pressure of air received at the transfer port [116h] and the second pressure of air
supplied at the equilibrating chamber [116g] is defined by the dimensions of the
relay piston [116a] and the end cover [116d] of the relay valve arrangement
[116]. In the present embodiment, the first pressure is described to be
20 maintained at the 3.8 bar pressure, and the second pressure is described to be
attaining the 2.2 bar pressure. However, in an alternate embodiment with
changed dimensions of the relay piston [116a] and the end cover [116d], the first
pressure may be maintained at the 3.8 bar pressure, while the second pressure
attaining the 2.0 bar pressure. Furthermore, in the open position, the air at the
25 second pressure as received at the equilibrating chamber [116g] is supplied to
the brake cylinder port [114d] via the second flow passage [126b], and the
second chamber [128b] of the normal supply valve arrangement [118], is
supplied to the timing reservoir [122] via the second flow passage [126b], the
second chamber [128b] of the normal supply valve arrangement [118], and a
14
fourth flow passage [126d], and is supplied to the indicator [124] via the second
flow passage [126b], the second chamber [128b] of the normal supply valve
arrangement [118], and a fifth flow passage [126e].
The normal supply valve arrangement [118] is provided to perform the following
5 functions: to allow the supply of air as received from the brake cylinder port
[114d] at the first pressure to the brake cylinder port [114d] at the first pressure,
and to switch the relay valve [116e] from the closed position to the open
position as per load conditions of the wagon of the train. The normal supply
valve arrangement [118] includes a piston [118a], a driving stem [118b], a first
10 poppet valve [118c], and a second poppet valve [118d]. The piston [118a] is
positioned within a piston support portion of the housing [114], and the driving
stem [118b] is positioned in the stem support portion of the housing [114]. The
first poppet valve [118c] and the second poppet valve [118d] are installed on the
driving stem [118b]. With such arrangement, various chambers are defined in
15 the housing [114]. In particular, a first chamber [128a] is defined between the
piston [118a] and the first poppet valve [118c] within the housing [114], a second
chamber [128b] is defined between the first poppet valve [118c] and the second
poppet valve [118d], and a third chamber [128c] is defined between the second
poppet valve [118d] and a distant end of the driving stem [118b]. The first
20 chamber [128a] is fluidly connected to the distributor port [114c] via a sixth flow
passage [126f]. The second chamber [128b] is fluidly connected to the brake
cylinder port [114d] via a seventh flow passage [126g], and is fluidly connected
to the equilibrating chamber [116g] via the second flow passage [126b].
Moreover, the third chamber [128c] is fluidly connected to the timing reservoir
25 [122] and the indicator [124] via the fourth flow passage [126d] and the fifth flow
passage [126e], respectively. The normal supply valve arrangement [118] is
adapted to operate in a normal mode and a pressure-cut mode.
In the normal mode of operation of the normal supply valve arrangement [118],
the relay valve arrangement [116] is maintained in the closed position and is
15
therefore inoperative. In the normal mode, the first poppet valve [118c] is
normally open and the second poppet valve [118d] is normally closed. Therefore,
in such conditions, a flow of air from the first chamber [128a] to the second
chamber [128b] is allowed, while the flow of air from the second chamber [128b]
5 to the third chamber [128c] is restricted. In such mode of operation, the air as
received at the distributor port [114c] at the first pressure is supplied to the first
chamber [128a] via the sixth flow passage [126f] at the first pressure. Thereafter,
as the first poppet valve [118c] is open, the air is supplied from the first chamber
[128a] to the second chamber [128b] at the first pressure. Moreover, the second
10 poppet valve [118d] being closed, the air is restricted to flow from the second
chamber [128b] to the third chamber [128c]. In such situations, the air flows
from the second chamber [128b] to the brake cylinder port [114d] via the
seventh flow passage [126g] at the first pressure. Therefore, in the normal mode
of operation, the air as received at the distributor port [114c] at the first
15 pressure is supplied to the distributor port [114c] at the first pressure. In such
situations, the pilot chamber [116f] of the relay valve arrangement [116] receives
air at the first pressure from the distributor port [114c] via the first flow passage
[126a], and the equilibrating chamber [116g] of the relay valve arrangement
[116] receives air at the first pressure from the second chamber [128b] via the
20 second flow passage [126b]. As the pressure of air in the pilot chamber [116f]
balances the pressure of air in the equilibrating chamber [116g], the relay valve
arrangement [116] is maintained in the closed position during a normal mode of
operation of the normal supply valve arrangement [118].
In the pressure-cut mode of operation of the normal supply valve arrangement
25 [118], the relay valve arrangement [116] is adjusted to the open position and is
therefore operative. In the pressure-cut mode, the first poppet valve [118c] is
closed and the second poppet valve [118d] is open. Therefore, in such
conditions, a flow of air from the first chamber [128a] to the second chamber
[128b] is restricted, while the flow of air from the second chamber [128b] to the
16
third chamber [128c] is allowed. In such mode of operation, the air as received
previously at the brake cylinder port [114d] is supplied from the second chamber
[128b] to the third chamber [128c], and later to the timing reservoir [122] via the
fourth flow passage [126d] and to the indicator [124] via the fifth flow passage
5 [126e]. This results in a drop in pressure of air at the second chamber [128b]. The
air with such drop in pressure, is also supplied to the equilibrating chamber
[116g] of the relay valve arrangement [116] via the second flow passage [126b].
Moreover, the pilot chamber [116f] of the relay valve arrangement [116]
receives air at the pressure received the distributor port [114c] via the first flow
10 passage [126a]. Therefore, a disbalance in pressure of air supplied to the pilot
chamber [116f] and the equilibrating chamber [116g] is resulted, causing the
relay valve [116e] to be switched to the open position by movement of the relay
piston [116a]. As the relay valve arrangement [116] is switched from the closed
position to the open position, it operates to receive air at the first pressure at the
15 distributor port [114c], alter the pressure of air, and supply the air at the second
pressure to the brake cylinder port [114d] via the second flow passage [126b],
the second chamber [128b] of the normal supply valve arrangement [118], and
the seventh flow passage [126g] at the distributor port [114c] at the first
pressure is supplied to the first chamber [128a] via the sixth flow passage [126f].
20 It may be contemplated that an operation of the relay valve arrangement [116]
and the normal supply valve arrangement [118] is supplementary to each other.
Particularly, in the normal mode of operation of the normal supply valve
arrangement [118], the relay valve arrangement [116] is adjusted to the closed
position, while in the pressure-cut mode of operation of the normal supply valve
25 arrangement [118], the relay valve arrangement [116] is adjusted to the open
position. Furthermore, it may be required to adjust the relay valve arrangement
[116] and the normal supply valve arrangement [118] based on load conditions
of the wagon of the train. In particular, in a loaded condition of the wagon of the
train, i.e. when the wagon is loaded with goods above predefined weight, the
17
normal supply valve arrangement [118] is required to operate in the normal
mode of operation and the relay valve arrangement [116] is required to be
adjusted to the closed position. Moreover, in an empty condition of the wagon of
the train, i.e. when the wagon is not loaded or loaded with goods below
5 predefined weight, the normal supply valve arrangement [118] is required to
operate in the pressure-cut mode of operation and the relay valve arrangement
[116] is required to be adjusted to the open position.
The control mechanism [120] is provided to switch the normal supply valve
arrangement [118] between the normal mode and the pressure-cut mode, and
10 to switch the relay valve arrangement [116] between the closed position and the
open position. The control mechanism [120] includes a swing arm [120a] and a
connection rod [120b]. The swing arm [120a] is pivotally installed on the housing
[114] of the APM system [110], and includes a stopper head. The connection rod
[120b] is connected to the piston [118a] of the normal supply valve arrangement
15 [118], and is attached to the swing arm [120a]. In particular, one end of the
connection rod [120b] is connected to the piston [118a] of the normal supply
valve arrangement [118] via a spherical head configuration, and is fixedly
attached to the swing arm [120a] with use of fixed attachment means. Such
attachment of the connection rod [120b] via the spherical head configuration
20 prevents translation of vibration of the swing arm [120a] to the piston [118a],
and ensures appropriate operation of the APM system [110]. The connection rod
[120b] translates a linear movement of the piston [118a] of the normal supply
valve arrangement [118] to the swing arm [120a]. In particular, the swing arm
[120a] performs a pivotal movement responsive to a movement of the piston
25 [118a] of the normal supply valve arrangement [118]. The pivotal movement of
the swing arm [120a] is stopped prematurely to stop linear movement of the
piston [118a] by stopping the stopper head of the swing arm [120a], in the
loaded conditions of the wagon of the train. Thereby, the normal supply valve
arrangement [118] is maintained in the normal mode of operation and the relay
18
valve arrangement [116] is maintained in the closed position. Furthermore, the
pivotal movement of the swing arm [120a] is allowed freely (Without restriction)
to allow free linear movement of the piston [118a], in the empty conditions of
the wagon of the train. Thereby, the normal supply valve arrangement [118] is
5 switched to the pressure-cut mode of operation and the relay valve arrangement
[116] is switched to the open position. Furthermore, a rubber stopper is installed
in the swing arm [120a], to prevent direct contact of the swing arm [120a] with
the housing [114] of the APM system [110] and prevent translation of vibration
to the APM system [110].
10 With the aforementioned structure and arrangement, the APM system [110] is
capable of operating differently in each of the following four conditions: i) brake
application operation during loaded conditions of the wagon of the train; ii)
brake release operation during loaded conditions of the wagon of the train; iii)
brake application operation during empty conditions of the wagon of the train;
15 iv) brake release operation during empty conditions of the wagon of the train. An
operation of the APM system [110] in each of these conditions will be described
in detail in the forthcoming disclosure.
i) Brake Application Operation in Loaded Conditions of the Wagon of the Train
Referring to FIGS. 3a-3b, initially, the brake pipe [102] of the brake system [100]
20 is supplied with the upper brake pressure. In the preferred embodiment, the
upper brake pressure is 5 bar pressure. During applications of brake in the
loaded conditions of the wagon of the train, the brake pipe [102] releases air to
attain the lower brake pressure. In the preferred embodiment, the lower brake
pressure is 3.5 bar pressure. This change in pressure in the brake pipe [102] is
25 sensed by the C3W distributor valve [108], to output air at the first pressure to
the APM system [110]. In the preferred embodiment, the first pressure of air as
outputted by the C3W distributor valve [108] is 3.8 bar pressure. The APM
system [110] in such condition receives the air from the C3W distributor valve
[108] at the first pressure, and supplies air to the brake cylinders [112] at the first
19
pressure. Therefore, the brake cylinders [112] receives air at the first pressure of
3.8 bar pressure. The brake cylinders [112] upon receiving the air at the first
pressure performs brake application operation with relatively higher strength.
In such conditions, the APM system [110] receives air at the first pressure at the
5 distributor port [114c]. The relay valve arrangement [116] is normally maintained
in the closed position, and the normal supply valve arrangement [118] is
maintained in the normal mode of operation. It may be noted that the receipt of
air at the distributor port [114c] is a continuous process, i.e., the pressure at the
distributor port [114c] gradually increases to reach the first pressure at the
10 distributor port [114c]. During start of receiving air at the distributor port [114c],
as the normal supply valve arrangement [118] is maintained in the normal mode
of operation, the air as received at the distributor port [114c] flows to the first
chamber [128a] of the normal supply valve arrangement [118] via the sixth flow
passage [126f]. This corresponds to a linear movement of the piston [118a] of
15 the normal supply valve arrangement [118], which corresponds to the pivotal
movement of the swing arm [120a]. As the first poppet valve [118c] is open in
the normal mode of operation of the normal supply valve arrangement [118], the
air flows to the second chamber [128b] of the normal supply valve arrangement
[118]. From the second chamber [128b] of the normal supply valve arrangement
20 [118], the air flows to the brake cylinder port [114d] via the seventh flow passage
[126g]. As the second poppet valve [118d] is closed, the flow of air from the
second chamber [128b] to the timing reservoir [122] and the indicator [124]
through the third chamber [128c] is restricted. As the vehicle is in the loaded
condition, a pivotal movement of the swing arm [120a] is prematurely restricted
25 beyond a limit, and thus a linear movement of the piston [118a] and the
connection rod [120b] is restricted. Thereby, the normal supply valve
arrangement [118] is maintained in the normal mode of operation. In parallel to
such flow of air, the pilot chamber [116f] of the relay valve arrangement [116] is
supplied with air from the distributor port [114c] via the first flow passage
20
[126a], and the equilibrating chamber [116g] of the relay valve arrangement
[116] is supplied with air from the brake cylinder port via the second chamber
[128b] and the second flow passage [126b]. As the pressure at the brake cylinder
port [114d] equals the pressure at the distributor port [114c], a pressure in the
5 equilibrating chamber [116g] balances the pressure in the pilot chamber [116f].
Such balance in pressure at the pilot chamber [116f] and the equilibrating
chamber [116g] corresponds to maintaining of the relay valve arrangement [116]
in the closed position. Thereafter, as the pressure of air received at the
distributor port [114c] rises to the first pressure, the air as received at the first
10 pressure at the distributor port [114c] is supplied to the brake cylinder port
[114d] at the first pressure, via the sixth flow passage [126f], the first chamber
[128a], the second chamber [128b], and the seventh flow passage [126g].
ii) Brake Release Operation during Loaded Conditions of the Wagon of the Train
Referring to FIGS. 4a-4b, upon release of brake by the train operator, the
15 pressure in the brake pipe [102] of the brake system [100] is again supplied with
the upper brake pressure. This change in pressure in the brake pipe [102] is
sensed by the C3W distributor valve [108], to suck back/ release air from the
brake cylinders [112] via the APM system [110]. The brake cylinders [112] upon
release of air releases brakes from the wagon of the train.
20 For such purposes, the APM system [110] releases air by sucking back air from
the brake cylinder port [114d] to the distributor port [114c]. As the relay valve
arrangement [116] is maintained in the closed position, and the normal supply
valve arrangement [118] is maintained in the normal mode of operation, the
release of air from the brake cylinder port [114d] to the distributor port [114c]
25 occurs by flowing air via the seventh flow passage [126g], the second chamber
[128b], the first chamber [128a], and the sixth flow passage [126f]. This
corresponds to release of air from the brake cylinder port [114d] to the
distributor port [114c], to release air from the brake cylinders [112] to the C3W
distributor valve [108].
21
iii) Brake Application Operation during Empty Conditions of the Wagon of the
Train
Referring to FIGS. 5a-5d, initially, the brake pipe [102] of the brake system [100]
is supplied with the upper brake pressure. In the preferred embodiment, the
5 upper brake pressure is 5 bar pressure. During applications of brake in the
loaded conditions of the wagon of the train, the brake pipe [102] releases air to
attain the lower brake pressure. In the preferred embodiment, the lower brake
pressure is 3.5 bar pressure. This change in pressure in the brake pipe [102] is
sensed by the C3W distributor valve [108], to output air at the first pressure to
10 the APM system [110]. In the preferred embodiment, the first pressure of air as
outputted by the C3W distributor valve [108] is 3.8 bar pressure. The APM
system [110] in such condition receives the air from the C3W distributor valve
[108] at the first pressure, and supplies air to the brake cylinders [112] at the
second pressure. In the preferred embodiment, the second pressure is 2.2 bar
15 pressure. Therefore, the brake cylinder [112] receives air at the first pressure of
2.2 bar pressure. The brake cylinders [112] upon receiving the air at the second
pressure performs brake application operations with relatively lower strength.
In such conditions, the APM system [110] receives air at the first pressure at the
distributor port [114c]. The relay valve arrangement [116] is initially maintained
20 in the closed position, and the normal supply valve arrangement [118] is initially
maintained in the normal mode of operation. It may be noted that the receipt of
air at the distributor port [114c] is a continuous process, i.e., the pressure at the
distributor port [114c] gradually increases to reach the first pressure at the
distributor port [114c]. During start of receiving air at the distributor port [114c],
25 as the normal supply valve arrangement [118] is maintained in the normal mode
of operation, the air as received at the distributor port [114c] flows to the first
chamber [128a] of the normal supply valve arrangement [118] via the sixth flow
passage [126f]. This corresponds to a linear movement of the piston [118a] of
the normal supply valve arrangement [118], which corresponds to the pivotal
22
movement of the swing arm [120a]. As the first poppet valve [118c] is open in
the normal mode of operation of the normal supply valve arrangement [118], the
air flows to the second chamber [128b] of the normal supply valve arrangement
[118]. From the second chamber [128b] of the normal supply valve arrangement
5 [118], the air flows to the brake cylinder port [114d] via the seventh flow passage
[126g]. Simultaneously, as the second poppet valve [118d] is closed, the flow of
air from the second chamber [128b] to the timing reservoir [122] and the
indicator [124] through the third chamber [128c] is restricted. As the vehicle is in
the empty condition, a pivotal movement of the piston [118a] is not restricted
10 and allowed beyond a changeover limit, and thus a linear movement of the
piston [118a] is allowed beyond the changeover limit. Upon rise in pressure at
the distributor valve [108] and further linear movement of the piston [118a]
beyond the changeover limit, the first poppet valve [118c] is closed and the
second poppet valve [118d] is open. Such action causes switching of the normally
15 supply valve arrangement to the pressure-limit mode of operation. As the second
poppet valve [118d] is closed, a supply of air from the first chamber [128a] to the
second chamber [128b] is restricted. Concurrently, the air already supplied to the
brake cylinders [112] flows from the brake cylinder port [114d] to the timing
reservoir [122] via a combination of the seventh flow passage [126g], the second
20 chamber [128b], the third chamber [128c], and the fourth flow passage [126d].
Also, the air already supplied to the brake cylinders [112] flows from the brake
cylinder port [114d] to the indicator [124] via a combination of the seventh flow
passage [126g], the second chamber [128b], the third chamber [128c], and the
fifth flow passage [126e]. Such flow of air from the brake cylinder port [114d] to
25 the timing reservoir [122] and the indicator [124], causes the drop in pressure of
the air relative to the pressure at the brake cylinder port [114d]. In particular, the
pressure of air at the brake cylinder port [114d] is less than the pressure of air
the distributor port [114c]. In parallel to this, the pilot chamber [116f] of the
relay valve arrangement [116] receives air at the pressure from the distributor
23
port [114c] via the first flow passage [126a], and the equilibrating chamber
[116g] receives air at the pressure of the brake cylinder port [114d] via the
combination of the second chamber [128b] and the second flow passage [126b].
Due to a difference in pressure and volume at the pilot chamber [116f] and the
5 equilibrating chamber [116g], the relay valve [116e] is switched to the open
position. Thereafter, the pressure of air received at the distributor port [114c]
rises to the first pressure. In the open position, the relay valve [116e] receives air
at the first pressure at the transfer port [116h] from the distributor port [114c]
via the first flow passage [126a]. Moreover, in the open position, the relay valve
10 [116e] supplies air through the transfer port [116h] to the equilibrating chamber
[116g] at the second pressure. Furthermore, the air at the equilibrating chamber
[116g] at the second pressure is supplied to the brake cylinder port [114d] via
the combination of the second flow passage [126b], the second chamber [128b],
and the seventh flow passage [126g]. In particular, as the pressure of air received
15 at the distributor port [114c] rises to the first pressure, the air as received at the
first pressure at the distributor port [114c] is supplied to the brake cylinder port
[114d] at the second pressure, via the combination of the second flow passage
[126b], the second chamber [128b], and the seventh flow passage [126g].
Thereby, the brake cylinders [112] are supplied with air the second pressure.
20 It may be noted, in such conditions, the APM system [110] receives air at the first
pressure of 3.8 bar at the distributor port [114c] and supplies air at the second
pressure of 2.2 bar at the brake cylinder port [114d]. In certain situations, such as
deployment of the same brake system [100] on a new wagon of a new train, the
APM may require to receive the air at the first pressure of 3.8 bar at the
25 distributor port [114c] and supplies air at the new second pressure of 2.0 bar at
the brake cylinder port [114d]. In such conditions, the APM may be accessed to
remove the end cover [116d] and the relay piston [116a] from the APM system
[110]. As the relay valve arrangement [116] is installed at the second end [114b]
of the housing [114], the end cover [116d] and the relay piston [116a] may be
24
relatively easily accessed through the second end [114b] of the housing [114]. In
particular, the end cover [116d] may be uninstalled therefrom, and the relay
piston [116a] may be accessed through the second end [114b] to access the end
cover [116d] and the relay piston [116a]. As the ratio between the first pressure
5 and the second pressure is dependent on the dimensions of the end cover [116d]
and the relay piston [116a], in order to obtain the new second pressure, the end
cover [116d] and the relay piston [116a] may be replaced with new end cover
and the new relay piston. Thereby, with such replacement of the end cover
[116d] and the relay piston [116a] with new end cover and the new relay piston,
10 the APM system [110] is capable of receiving the air at the first pressure at the
distributor port [114c] and of supplying the air at the new second pressure to the
brake cylinder port [114d], during braking applications in the empty condition.
Moreover, when required to service components of the relay valve arrangement
[116], they may be easily accessed through the second end [114b] of the housing
15 [114] in the similar manner, and may be easily serviced. This reduces an overall
installation cost in case of switch in requirements by different trains. Moreover,
this reduces the maintenance cost and effort to service/ replace components of
the relay valve arrangement [116] in the APM system [110].
iv) Brake Release Operation during Empty Conditions of the Wagon of the Train
20 Referring to FIGS. 6a-6b, the release applications in empty conditions occurs via a
pressure relief valve [130] disposed at an interface of the sixth flow passage
[126f] and the second flow passage [126b]. Upon release of brake by the train
operator, the pressure in the brake pipe [102] of the brake system [100] is again
supplied with the upper brake pressure. This change in pressure in the brake
25 pipe [102] is sensed by the C3W distributor valve [108], to suck back/ release air
from the brake cylinders [112] via the APM system [110]. The brake cylinders
[112] upon release of air releases brakes from the wagon of the train.
For such purposes, the APM system [110] releases air by sucking back air from
the brake cylinder port [114d], the timing reservoir [122], and the indicator
25
[124]. Notably, the relay valve arrangement [116] is maintained in the open
position, and the normal supply valve arrangement [118] is in the pressure-cut
mode of operation. Upon drop in pressure, the pressure relief valve [130] is
opened. This causes the air in the brake cylinder port [114d] to be released
5 through the pressure relief valve [130] via the seventh flow passage [126g], the
second chamber [128b], and the second flow passage [126b]. Moreover, the air
in the timing reservoir [122] is released through the pressure relief valve [130]
via the fourth flow passage [126d], the third chamber [128c], the second
chamber [128b], and the second flow passage [126b]. Additionally, the air in the
10 indicator [124] is released through the pressure relief valve [130] via the fifth
flow passage [126e], the third chamber [128c], the second chamber [128b], and
the second flow passage [126b]. Furthermore, the air in the first chamber [128a]
is released through the pressure relief valve [130] via the sixth flow passage
[126f]. Upon such release of air from the first chamber [128a], the piston [118a]
15 linearly moves forward, and the swing arm [120a] performs a return pivotal
movement. Such forward movement of the piston [118a] correspond to
switching back of the normal supply valve arrangement [118] from the pressurecut mode to the normal mode of operation. Thereby, air is released from the
brake cylinder port [114d], and release of air from the brake cylinders [112].
20 While the preferred embodiments of the present invention have been described
hereinabove, it should be understood that various changes, adaptations, and
modifications may be made therein without departing from the spirit of the
invention and the scope of the appended claims. It will be obvious to a person
skilled in the art that the present invention may be embodied in other specific
25 forms without departing from its spirit or essential characteristics. The described
embodiments are to be considered in all respects only as illustrative and not
restrictive.
List of Components:
100 – Brake System
26
102 – Brake Pipe
104 – Wagon Brake System
106 – Auxiliary Reservoir
108 – C3W Distributor Valve
5 110 – Automatic Pressure Modification (APM) System
112 – Brake Cylinders
114 – Housing
114a, 114b – First and Second End of 114
114c - Distributor Port of 114
10 114d - Brake Cylinder Port of 114
114e - Timing Reservoir Port of 114
114f - Indicator Port of 114
114g – Relay Support Portion of 114
116 – Relay valve Arrangement
15 116a – Relay Piston of 116
116b – First Diaphragm of 116
116c – Second Diaphragm of 116
116d – End Cover of 116
116e – Relay Valve of 116
20 116f – Pilot Chamber of 116
116g – Equilibrating Chamber of 116
116h – Transfer Port of 116e
116i – Balance Port of 116e
118 – Normal Supply Valve Arrangement
25 118a - Piston
118b - Driving Stem
118c - First Poppet valve
118d - Second Poppet valve
120 – Control Mechanism
27
122 – Timing Reservoir
124 – Indicator
126a, 126b, 126c, 126d, 126e, 126f, 126g – Flow Passages
128a – First Chamber
5 128b – Second Chamber
128c – Third chamber
130 – Pressure Relief Valve

We Claim:
1. An automatic pressure modification (APM) system [110] for receiving air at
a first pressure at a distributor port [114c] and selectively supplying air at
one of the first pressure and a second pressure to a brake cylinder port
5 [114d], the APM system [110] comprising:
- a housing [114] including a first end [114a] and a second end
[114b];
- a relay valve arrangement [116] fluidly positioned between the
distributor port [114c] and the brake cylinder port [114d] within the
10 housing [114], the relay valve arrangement [116] being adapted to operate
in a closed position and an open position, such that the relay valve
arrangement [116] facilitates a change in air pressure from the first
pressure received at the distributor port [114c] to the second pressure
supplied at the brake cylinder port [114d] in a predefined ratio in the open
15 position, the relay valve arrangement [116] including a relay piston [116a],
at least one diaphragm [116b, 116c], a relay valve [116e]; and an end cover
[116d] covering the second end [114b] of the housing [114]; wherein
the relay piston [116a] and the end cover [116d] define the
predefined ratio between the first pressure of air received at the
20 distributor port [114c] and the second pressure of air supplied at
the brake cylinder port [114d],
the relay piston [116a] and the end cover [116d], may be
accessed through the second end [114b] of the housing [114], for
enabling replacement of one or more of the relay piston [116a]
25 and the end cover [116d], for altering the predefined ratio
between the first pressure of air received at the distributor port
[114c] and the second pressure of air supplied at the brake
cylinder port [114d].
29
2. The APM system [110] as claimed in claim 1, wherein the at least one
diaphragm includes a first diaphragm [116b] and a second diaphragm
[116c] supported between an outer periphery of the relay piston [116a]
and an inner periphery of the housing [114].
5 3. The APM system [110] as claimed in claim 2, wherein the relay valve
arrangement [116] defines a pilot chamber [116f] at an interface of the
first diaphragm, and defines an equilibrating chamber [116g] at an
interface of the second diaphragm [116c] within the housing [114].
4. The APM system [110] as claimed in claim 1, wherein the relay valve [116e]
10 of the relay valve arrangement [116] is switched between the open
position and the closed position corresponding to a linear movement of the
relay piston [116a].
5. The APM system [110] as claimed in claim 1, wherein the relay valve [116e]
is positioned adjacent to the relay piston [116a] of the relay valve
15 arrangement [116].
6. The APM system [110] as claimed in claim 1, wherein the relay valve [116e]
includes a transfer port [116h] fluidly positioned between the distributor
port [114c] and the equilibrating chamber [116g], such that the relay valve
[116e] restricts a supply of the air through the transfer port [116h] in the
20 closed position, and the relay valve [116e] allows the supply of air through
the transfer port [116h] for enabling a pressure reduction defined by the
predefined ration in the open position.
7. The APM system [110] as claimed in claim 1, wherein the relay valve [116e]
is normally maintained in the closed position as the air pressure in the pilot
25 chamber [116f] balances the air pressure in the equilibrating chamber
[116g].
8. The APM system [110] as claimed in claim 1, wherein the relay valve [116e]
is adjusted to the open position as the air pressure in the pilot chamber
[116f] disbalances the air pressure in the equilibrating chamber [116g].
30
9. The APM system [110] as claimed in claim 1, further comprises a normal
supply valve arrangement [118] fluidly disposed between the distributor
port [114c] and the brake cylinder port [114d], the normal supply valve
arrangement [118] being adapted to operate between a normal mode
5 during operation of the relay valve arrangement [116] in the closed
position, and a pressure-cut mode during operation of the relay valve
arrangement [116] in the open position.
10. The APM system [110] as claimed in claim 8, wherein in the normal mode,
the normal supply valve arrangement [118] facilitates receiving of air at the
10 first pressure at the distributor port [114c] and supply of air at the first
pressure at the brake cylinder port [114d].
11. The APM system [110] as claimed in claim 8, wherein in the normal mode,
the normal supply valve arrangement [118] facilitates supply of air at the
first pressure to the equilibrating chamber [116g] of the relay valve
15 arrangement [116] for maintaining the relay valve [116e] in the closed
position.
12. The APM system [110] as claimed in claim 8, wherein the normal supply
valve arrangement [118] facilitates includes:
a piston [118a];
20 a driving stem [118b] fixedly attached to the piston [118a] and
extending with the housing [114];
a first poppet valve [118c] mounted on the driving stem [118b]
and positioned within the housing [114], the first poppet valve [118c]
defining:
25 a first chamber [128a] in fluid communication with the
distributor port [114c]; and
a second chamber [128b] in fluid communication with the
brake cylinder port [114d]; and
a second poppet valve [118d] mounted on the driving stem [118b]
31
and positioned within the housing [114], the second poppet valve [118d]
defining:
the second chamber [128b]; and
a third chamber [128c] in fluid communication with a
5 timing reservoir [122] and an indicator [124].
13. The APM system [110] as claimed in claims 9-12, wherein in the normal
mode the first poppet valve [118c] is open and allows the flow of air from
the distributor port [114c] to the brake cylinder port [114d] at the first
pressure, via the first chamber [128a], and the second chamber [128b],
10 thereby receiving the air at the first pressure at the distributor port [114c]
and supplying air at the first pressure at the brake cylinder port [114d].
14. The APM system [110] as claimed in claims 9-12, wherein in the normal
mode the second poppet valve [118d] is closed and restricts the flow of air
from the second chamber [128b] to the third chamber [128c], thereby
15 restricting the flow of air to the timing reservoir [122] and the indicator
[124].
15. The APM system [110] as claimed in claims 1-12, wherein the second
chamber [128b] of the normal supply valve arrangement [118] is fluidly
connected to the equilibrating chamber [116g] of the relay valve
20 arrangement [116], to supply air therein.
16. The APM system [110] as claimed in claims 9-12, wherein in the pressurecut mode, the first poppet valve [118c] is closed and restricts the flow of air
from the first chamber [128a] to the second chamber [128b], thereby
restricting the flow of air from the distributor port [114c] to the brake
25 cylinder port [114d] through the first chamber [128a] and the second
chamber [128b].
17. The APM system [110] as claimed in claims 9-12, wherein in the pressurecut mode, the second poppet valve [118d] is open and allows the flow of
air from the brake cylinder port [114d] to the timing reservoir [122] and
32
the indicator [124], thereby dropping the pressure at the second chamber
[128b] and the equilibrating chamber [116g] of the relay valve
arrangement [116].
18. The APM system [110] as claimed in claims 9-12, wherein cutting down of
5 pressure at the equilibrating chamber [116g] of the relay valve
arrangement [116] facilitates adjustment of the relay valve [116e] from the
closed position to the open position.
19. The APM system [110] as claimed in claims 1-18, further comprises a
control mechanism [120] including:
10 a swing arm [120a] pivotally connected to at least one portion of the
housing [114], and includes a hammer head;
a connection rod [120b] connected to the piston [118a] at one end and
attached to the swing arm [120a] at opposite end.
20. The APM system [110] as claimed in claim 19, wherein the swing arm
15 [120a] performs a pivotal movement, corresponding to a linear movement
of the piston [118a] and the connection rod [120b] of the normal supply
valve arrangement [118].
21. The APM system [110] as claimed in claim 19, wherein a pivotal movement
of the swing arm [120a] is prematurely restricted in a loaded condition, to
20 restrict a linear movement of the piston [118a] and the connection rod
[120b] and thus maintain the normal supply valve arrangement [118] in the
normal mode and the relay valve arrangement [116] in the closed position.
22. The APM system [110] as claimed in claim 19, wherein a pivotal movement
of the swing arm [120a] is freely allowed in an empty condition, to allow a
25 free linear movement of the piston [118a] and the driving arm and thus
allow the normal supply valve arrangement [118] to be switched to the
pressure-cut mode and switch the relay valve arrangement [116] to the
open position.
23. The APM system [110] as claimed in claim 18, wherein the connection rod
33
[120b] is connected to the driving stem [118b] by a spherical head
configuration.
24. The APM system [110] as claimed in claim 18, wherein the control
mechanism [120] includes a rubber stopper installed at a length of the
5 swing arm [120a], which is capable of engaging with the housing [114], for
restricting vibrations in the APM system [110].