The present disclosure relates to a brake cylinder for a bogie mounted brake
system (BMBS) of a train. More particularly, the present invention relates to a
slack adjusting arrangement of the brake cylinder for the bogie mounted brake
5 system (BMBS) of the train.
BACKGROUND
Bogie Mounted Brake Systems (BMBS) are commonly known to be employed in
trains for effective braking. A BMBS is installed on each car/wagon of a train, to
apply brakes on each car of the train. The BMBS is an air brake system that
10 operates on air pressure to apply braking on wheels of the car/wagon of the
train. The BMBS includes a pneumatic brake cylinder, and a brake mechanism
with multiple brake shoes. The brake cylinder and the brake mechanism are
suitably arranged with each other, such that expansion and retraction of the
brake cylinder corresponds to forward and backward movement of the brake
15 shoes of the brake mechanism relative to the wheels of the car/wagon of the
train. Such forward and backward movement of the brake shoes relative to the
wheels the car/wagon of the train, corresponds to application and removal of
brakes on the wheels respectively. Particularly, a predefined amount of
expansion and/or retraction of the brake cylinder corresponds to predefined
20 amount of forward and/or backward movement of the brake shoes of the brake
mechanism relative to the wheels of the car/wagon of the train, which further
corresponds to the brake application and/or removal on the wheels of the
car/wagon of the train.
Conventionally, the brake cylinder includes a housing, and a piston arrangement
25 slidingly arranged relative and extending within the housing. The piston
arrangement includes a solid piston face, and a solid piston rod linearly and
coaxially extending from the solid piston face. The piston arrangement receives
air at the piston face and thus slides forward and/or backward relative to the
housing. Forward and/or backward sliding of the piston arrangement relative to
3
the housing, corresponds to expansion and/or retraction of the brake cylinder.
With such arrangement of the conventional brake cylinders, it undergoes an
expansion and/or retraction only to a fixed predetermined amount of distance,
which further corresponds to a forward and/or backward movement of the
5 brake shoes only to the fixed predetermined amount of distance. Further, there
may be situations, such as wearing of the brake shoes (‘slack increased
conditions’), replacement of the old brake shoes with new brake shoes (‘slack
decreased conditions’), or improper positioning of the brake shoes on the brake
mechanism (either of ‘slack increased conditions’ or ‘slack decreased
10 conditions’), and the like. In such situations, a distance between the brake shoes
and the wheels, may either increase or decrease by a slack distance. The slack
distance may cause improper braking of the wheels of the car/wagon of the
train. For example, during wear out of the brake shoes, a distance between the
brake shoes and the wheels may increase by a slack distance, and causing the
15 ‘slack increased conditions’. However, the conventional brake cylinder is preset
to expand by the fixed predetermined amount of distance, and correspondingly
the brake shoes move forward by the fixed predetermined amount of distance.
In such situations, the brake shoes may not be able to contact the wheels, and
may fail to brake the wheels of the car/wagon of the train. A number of solutions
20 have been developed, for example a slack adjusting arrangement , to
compensate for the slack distance observed between the brake shoes and the
wheels of the car/wagon of the train, however, none of these solutions provides
relatively reliable and rugged slack adjusting arrangement. Particularly,
previously known slack adjusting arrangement are positioned independent of the
25 brake cylinder, which results in a complex arrangement of the BMBS.
Accordingly, in light of the aforementioned drawbacks and several other
inherent in the existing arts, there is a well felt need to provide a slack adjusting
mechanism in the BMBS, which provides relatively reliable, rugged, and less
complex, slack adjusting arrangement provided with the brake cylinder of the
4
BMBS.
SUMMARY
An object of the present invention relates to a brake cylinder of a bogie mounted
brake system (BMBS) for a train, including a slack adjusting arrangement
5 positioned within the brake cylinder. The slack adjusting arrangement
compensates for a slack distance observed between brake shoes and wheels of
the train. Particularly, the slack adjusting arrangement enables the brake
cylinder, to additionally expand by the slack distance (additional distance
observed between the brake shoes and the wheels of the train) observed
10 between the brake shoes and the wheels of the train in slack increased
conditions, and limits expansion by the slack distance (reduced distance
observed between the brake shoes and the wheels of the train) in slack
decreased conditions. The slack adjusting arrangement is provided as part of and
positioned within the brake cylinder. Thereby, the brake cylinder is relatively
15 more reliable, more efficient, more rugged, and less complex.
The present disclosure relates to a brake cylinder of a bogie mounted brake
system (BMBS) for a train. The brake cylinder includes a housing, a piston
arrangement, and a slack adjusting arrangement. The piston arrangement is
slideably arranged relative to and extending within the housing. The piston
20 arrangement includes a piston face with a central hole, and a hollow piston rod.
The piston arrangement further defines a first end portion at the piston face, and
a second end portion at the hollow piston rod. The second end portion of the
hollow piston rod [104] defines a first inner engagement teeth and a second
inner engagement teeth. The slack adjusting arrangement includes an adjuster
25 pipe, a screw rod, a pre‐compressed main spring arrangement, and a nut
member. The adjuster pipe is slideably arranged relative to and extending within
the housing, such that the adjuster pipe houses the second end portion of the
piston arrangement proximal to a slack adjustment end. The screw rod is
slideably arranged relative to the adjuster pipe and at least partially passes
5
through the piston rod. The screw rod further includes an external threaded
region. The pre‐compressed main spring arrangement is positioned between and
facilitates sliding movement of the screw rod relative to the adjuster pipe. In
particular, the pre‐compressed main spring arrangement includes a plurality of
5 springs connected in series, which are positioned between and facilitates sliding
movement of the screw rod relative to the adjuster pipe. The nut member
includes an adjuster end portion, an engagement end portion, and an internal
threaded region positioned in engagement with the external threaded region of
the screw rod. The engagement end portion of the screw rod is positioned within
10 the second end portion of the piston rod, and includes a first mating teeth and a
second mating teeth. The first mating teeth is capable of engaging with the first
engagement teeth, and the second mating teeth is capable of engaging with the
second engagement teeth of the piston rod. In a normal stroke, either of the first
mating teeth and the second mating teeth of the nut member engages with the
15 first engagement teeth and the second mating teeth of the piston rod, to restrict
a rotational motion of the nut member relative to the screw rod and thus restrict
a linear movement of the screw rod relative to the nut member. Moreover, in a
slack adjustment stroke, neither of the first mating teeth and the second mating
teeth of the nut member engages with the first engagement teeth and the
20 second mating teeth of the piston rod, to allow a rotational motion of the nut
member relative to the screw rod and thus allow a linear movement of the screw
rod relative to the nut member. Therefore, in the slack adjustment stroke, the
screw rod is linearly adjusted relative to the nut member by the slack distance. In
particular, in slack increased conditions, the screw rod is linearly moved forward
25 by the slack distance following the slack adjustment stroke. However, in the slack
decreased conditions, the screw rod is linearly moved backwards by the slack
distance following the slack adjustment stroke. Notably, a combination of an air
pressure on the first screw end portion of the screw rod [114] through the
central through hole in the piston face, and a spring force of the pre‐compressed
6
main spring arrangement, corresponds to the forward movement of the screw
rod [114] relative to the adjuster pipe [112] by the slack distance following the
slack adjusting stroke in the slack increased conditions.
BRIEF DESCRIPTION OF DRAWINGS
5 The present invention, both as to its organization and manner of operation,
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
10 only by way of illustration and not in limitation of the invention, and in which
drawings:
Figure 1 shows a sectional view of a brake cylinder of a bogie mounted brake
system of a car/wagon of a train, in a completely retracted position, in
accordance with the concepts of the present disclosure.
15 Figures 2a–2i shows sectional views of the brake cylinder of FIG. 1, illustrating
various positions of the brake cylinders, during braking/ brake release
operations, in the slack increased conditions of the brake cylinder, in accordance
with the concepts of the present disclosure.
Figures 3a–3h shows sectional views of the brake cylinder of FIG. 1, illustrating
20 various positions of the brake cylinders, during braking/ brake release
operations, in slack decreased conditions, in accordance with the concepts of the
present disclosure.
DETAILED DESCRIPTION
In the following description, for the purposes of explanation, various specific
25 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
one another or with any combination of other features. An individual feature
7
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
embodiments of the present invention are described below, as illustrated in
5 various drawings in which like reference numerals refer to the same parts
throughout the different drawings.
The present disclosure relates to a bogie mounted brake system (BMBS).
Particularly, a BMBS is installed on each car of a train, to enable brake
application on each car of the train. The BMBS employs a brake cylinder [100], a
10 pneumatic arrangement, and a brake mechanism. For ease in reference and
understanding, the pneumatic arrangement and the brake mechanism of the
BMBS, are not shown in details in the present disclosure.
The pneumatic arrangement is adapted to pneumatically activate and/or
deactivate the brake cylinder [100]. The pneumatic arrangement supplies air at
15 defined pressure to the brake cylinder [100] in order to facilitate expansion of
the brake cylinder [100]. Further, the pneumatic arrangement relieves air from
the brake cylinder [100] in order to retract the brake cylinder [100]. Although,
the pneumatic arrangement is described to supply air to the brake cylinder [100]
for enabling expansion of the brake cylinder [100], any other fluid may also be
20 used for enabling expansion of the brake cylinder [100]. Expansion and retraction
of the brake cylinder [100] will be explained later in details.
The brake mechanism is mechanically arranged with the brake cylinder [100],
and is adapted to support one or more brake shoes. The brake mechanism is
arranged, such that expansion and/or retraction of the brake cylinder [100]
25 corresponds to forward and/or backward movement of the one or more brake
shoes relative to the one or more wheel treads, in order to apply and/or remove
brakes on the one or more wheels treads of one or more wheels of a train.
Particularly, the brake mechanism supports four brake shoes separated by a
distance from four corresponding wheel treads, such that expansion and/or
8
retraction of the brake cylinder [100] corresponds to linear forward and/or
backward movement of the four brake shoes relative to the four wheel treads of
the four wheels of the train. Although, the brake mechanism is described to
employ four brake shoes to apply brakes on the four wheels of the train with use
5 of a singular brake cylinder [100], it may be contemplated that the brake
mechanism may employ any number of brake shoes to apply brakes on any
number of wheels of the train with use of a singular brake cylinder [100].
Further, the brake mechanism facilitates a forward and/or backward movement
of the four brake shoes relative to the wheel treads by a distance, upon an
10 expansion and/or retraction of the brake cylinder [100] by a distance. Although,
the distance of forward and/or backward movement of the four brake shoes by
the brake mechanism is described and explained as equal to the distance of
expansion and/ or retraction of the brake cylinder [100], it may be obvious to a
person skilled in the art that the distance of forward and/or backward movement
15 of the four brake shoes by the brake mechanism may be different from the
distance of expansion and/ or retraction of the brake cylinder [100]. For ease in
reference and understanding, the brake mechanism is not shown in figures of the
present disclosure.
Figure 1 shows a sectional view of the brake cylinder [100] of the BMBS of the
20 car/wagon of the train. The brake cylinder [100] is arranged to expand and/ or
retract, upon receiving and/or releasing pressurized air from the pneumatic
arrangement. As is already mentioned, expansion and/or retraction of the brake
cylinder [100] corresponds to forward and/or backward movement of the brake
shoes relative to the four wheels of the train. For ease in reference and
25 understanding, the brake shoes and the brake mechanism are not shown in the
figures, however, direct expansion and/or retraction of the brake cylinder [100]
relative to one of the wheel treads is shown in figures for illustrative purposes.
Further, it may be noted that the brake cylinder [100] is required to perform the
braking action, in each of a normal operating condition, a slack increased
9
operating condition (as is shown in Figs. 2a‐2i), and a slack decreased operating
condition (as is shown in Figs. 3a‐3h).
The brake cylinder [100] includes a housing [102], a piston rod arrangement
[104], and a slack adjusting arrangement [106]. The housing [102] is a
5 substantially cylindrical component with varying inner and external cross‐section
that houses either fully or partly houses other components of the brake cylinder
[100]. Particularly, the housing [102] houses the piston rod arrangement [104]
and one or more components of the slack adjusting arrangement [106]. The
housing [102] includes a first housing portion [102a] and a second housing
10 portion [102b], defined along a length of the housing [102]. The first housing
portion [102a] being relatively greater in inner diameter than the second housing
portion [102b], such that an internal step [102c] is formed at an interface
between the first housing portion [102a] and the second housing portion [102b].
The first housing portion [102a] also defines an air delivery port [102d], through
15 which entry and exit of the air from the pneumatic arrangement is facilitated.
Moreover, the first housing portion [102a] defines a piston guide cavity [102e] to
enable proper guiding of the piston rod arrangement [104] when supported
within the housing [102]. Additionally, the first housing portion [102a] of the
brake cylinder [100] includes an indicator cavity [102f] that houses an indicator
20 rod [108]. The indicator rod [108] is fixedly attached to the piston rod
arrangement [104] at one end and is exposed to environment at the other end,
such that a linear movement of the piston rod arrangement [104] within the
housing [102] corresponds to a linear movement of the indicator rod [108].
Therefore, a distance of sliding of the piston rod arrangement [104] relative to
25 the housing [102] results in corresponding length of exposure of the indicator
[108] to external environment, to indicate the amount of sliding of the piston rod
arrangement [104] within the housing [102]. Additionally, a rubber bellow (not
shown) is provided on an outer periphery of the housing [102], for protecting the
housing [102], the piston rod arrangement [104], and the slack adjusting
10
arrangement [106] from damage by objects in external environment.
Particularly, the hollow bellow protects the brake cylinder [100] from damage,
caused due to external objects.
The piston rod arrangement [104] includes a piston face [104a], and a hollow
5 piston rod [104b] coaxially attached to the piston face [104a], and a guide
portion [104c] non‐coaxially attached to the piston face [104a]. Moreover, the
piston arrangement defines a first end portion [104f] at the piston face [104a],
and a second end portion [104g] at the hollow piston rod [104b]. The piston face
[104a] has a central hole [104d] therein, and the hollow piston rod [104b] has an
10 internal cavity [104e] therein fluidly connected to the central hole [104d] of the
piston face [104a]. The hollow piston rod [104b] defines a first inner engagement
teeth [104h] and a second engagement teeth [104i], along an inner periphery at
the second end portion [104g] of the piston rod arrangement [104]. Further, the
piston rod arrangement [104] is positioned within and coaxially aligned with the
15 housing [102]. The piston rod arrangement [104] is positioned, such that the
piston face [104a] is positioned within the first housing portion [102a], the
hollow piston rod [104b] is positioned partly within the first housing portion
[102a] and partly within the second housing portion [102b]. In particular, the
piston face [104a] is positioned within the first housing portion [102a] of the
20 housing [102], such that an outer diameter of the piston face [104a] sealingly
mates with the inner diameter of the first housing portion [102a] of the housing
[102]. The piston face [104a] is exposed to air received from the pneumatic
arrangement within the housing [102]. Moreover, the hollow piston rod [104b] is
positioned partly within the first housing portion [102a] and partly within the
25 second housing portion [102b], such that the second end portion [104g] of the
hollow piston rod [104] is positioned within the second housing portion [102b] of
the housing [102]. Further, with the guide portion [104a] extends within the
piston guide cavity [102e] of the housing [102], to ensure proper sliding relative
to the housing [102]. Furthermore, the piston rod arrangement [104] is resiliently
11
slideably arranged relative to the housing [102]. “Resiliently slideably arranged”
of a component relative to a base component herein refers to the positioning of
the component relative to the base component, such that the component can
slide forward and/or backward relative to the base component while a spring
5 member is resiliently connected therebetween. Accordingly, a first resilient
spring member [110] is provided between the first end portion [104f] of the
piston rod arrangement [104] and the internal step [102c] of the housing [102],
for enabling resiliently sliding forward and backward movement of the piston rod
arrangement [104] relative to the housing [102]. Particularly, the first resilient
10 spring member [110] maintains the piston rod arrangement [104] to a retracted
backwards position relative to the housing [102]. The piston rod arrangement
[104] is allowed to slide relative to the housing, for a maximum piston stroke, ‘S”.
‘A’, ‘A1’, and ‘A2’ refers to the distance between the brake shoes and the wheel
treads of the brake mechanism, in the normal conditions, the slack increased
15 conditions, and the slack decreased conditions, respectively.
‘W1’ and ‘W2’ refers to a slack distance, which is the increase and/or decrease in
distance between the brake shoes and the wheel treads, in the slack increased
conditions and the slack decreased conditions, respectively.
‘ES’ refers to the elasticity stoke, particularly, a distance of expansion of the
20 brake cylinder [100] to enable braking of the brake shoes to the wheel treads,
while the brake shoes compress by ‘ES’ distance.
Although, the aforementioned distances are distance of the wheel treads relative
to the brake shoes, however as the brake shoes are not shown for illustrative
purposes, the distances are shown and described as distance of the wheel treads
25 relative to one or more components of the slack adjusting arrangement [106]. It
may be obvious to a person skilled in the art to refer the distances of the wheel
treads relative to the one or more components of the slack adjusting
arrangement [106] as described herein, will correspond to same distances of the
wheel treads relative to the brake shoes.
12
The slack adjusting arrangement [106] is provided, in combination with the
piston rod arrangement [104], to enable the brake cylinder [100] to expand
additionally and/ or expand reductional corresponding to the slack distances,
‘W1’ and ‘W2’, observed between the brake shoes and the wheel treads.
5 Particularly, the slack adjusting arrangement [106], in combination with the
piston rod arrangement [104], enables the brake cylinder [100] to expand by a
nominal distance of ‘A+ES’ in normal operating conditions of the BMBS, to
expand by a distance of ‘A1+ES’ (determined as A+W1+ES) in a slack increased
operating conditions, and to expand by a distance of ‘A2+ES’ (determined as A‐
10 W2+ES) in a slack decreased operating conditions. In particular, the slack
adjusting arrangement [106], in combination with the piston rod arrangement
[104], enables the brake cylinder [100] to expand additionally by ‘W1’ slack
distance in the slack increased operating conditions, and to expand reductional
by the ‘W2’ slack distance in the slack decreased operating conditions. In other
15 words, the slack adjusting arrangement [106] is suitably structured and arranged,
such that the slack adjusting arrangement [106] allows for expansion of ‘A1+ES’
(determined as A+W1+ES) and ‘A2+ES’ (determined as A‐W2+ES), respectively, in
a slack increased operating conditions and a slack decreased operating
conditions, and a retraction of ‘A+ES’ only in each of slack increased operating
20 conditions and a slack decreased operating conditions. The slack adjusting
arrangement [106] includes an adjuster pipe [112], a screw rod [114], a main
spring [122], a nut member [116], and a slack member [118].
The adjuster pipe [112] includes a first adjuster end portion [112a] and a second
adjuster end portion [112b]. The adjuster pipe [112] is positioned within and
25 coaxially aligned with the housing [102]. For such purpose, the adjuster pipe
[112] is supported over at least one portion of the piston rod arrangement [104],
such that the first adjuster end portion [112a] extends within the first housing
portion [102a] of the housing [102] and the second adjuster end portion [112b]
extends within the second housing portion [102b] of the housing [102]. Notably,
13
the second adjuster end portion [112b] of the adjuster pipe [112] extends
beyond the second end portion [104g] of the hollow piston rod [104], and
includes a slack adjustment end [112c] (hereinafter interchangeably referred to
as a stopper [112c]). Further, the adjuster pipe [112] is resiliently slideably
5 arranged relative to the housing [102]. “Resiliently slideably arranged” of a
component relative to a base component herein refers to the positioning of the
component relative to the base component, such that the component can slide
forward and/or backward relative to the base component while a spring member
is resiliently connected therebetween. Accordingly, a second resilient spring
10 member [120] is provided between the first adjuster end portion [112a] of the
adjuster pipe [112] and the internal step [102c] of the housing [102], for enabling
resilient sliding forward and backward movement of the adjuster pipe [112]
relative to the housing [102]. Particularly, the second resilient spring member
[120] maintains the adjuster pipe [112] to a retracted backward position relative
15 to the housing [102].
The screw rod [114] includes a core section [114a] and an external section
[114b]. The core section [114a] includes a first screw end portion [114c] and a
second screw end portion [114d]. Also, the core section [114a] defines an
external threaded region [114e], proximal to the second screw end portion
20 [114d]. The external section [114b] is attached to the second screw end portion
[114d] of the core section [114a], while defining a distance between the core
section [114a] and the external section [114b]. The screw rod [114] is positioned
coaxially aligned with the hollow piston rod [104b]. For such arrangement, the
screw rod [114] is positioned, such that at least one portion of the core section
25 [114a] extends within and supported by the internal cavity [104e] of the hollow
piston rod [104b] of the piston rod arrangement [104]. Particularly, the first
screw end portion [114c] of the core section [114a] is positioned within the
internal cavity [104c] of the hollow piston rod [104b]. The second screw end
portion [114d] of the screw rod [114] extends beyond the second end portion
14
[104g] of the hollow piston rod [104b], the second adjuster end portion [112b] of
the adjuster pipe [112], and the second housing end portion [102b] of the
housing [102]. Further, the external section [114b] being attached to the second
screw end portion [114d] of the core section [114a], the external section [114b]
5 of the screw rod [114] extends outwards of the hollow piston rod [104b], such
that the outer diameter of the external section [114b] sealingly mates with the
inner diameter of the second housing portion [102b] of the housing [102]. With
such arrangement, the first screw end portion [114c] is exposed to an air
pressure of the air received from the pneumatic arrangement at the first end
10 portion [104f] of the piston rod arrangement [104] through the central hole
[104d] in the piston face [104a] and the internal cavity [104e] of the hollow
piston rod [104b]. Particularly, the central hole [104d] in the piston face [104a]
allows a portion of air received on the piston face [104a], to enter the internal
cavity [104e] of the hollow piston rod [104b] and exert the air pressure on the
15 first screw end portion [114c] of the core section [114a] as well. Further, the
screw rod [114] is resiliently slideably arranged relative to the adjuster pipe
[112]. “Resiliently slideably arranged” of a component relative to a base
component herein refers to the positioning of the component relative to the
base component, such that the component can slide forward and/or backward
20 relative to the base component while a spring member is resiliently connected
therebetween. Accordingly, the pre‐compressed main spring arrangement [122]
is provided between the second screw end portion [114d] of the screw rod [114]
and the first adjuster end portion [112a] of the adjuster pipe [112], for enabling
sliding forward and backward movement of the screw rod [114] relative to the
25 adjuster pipe [112]. Particularly, the pre‐compressed main spring arrangement
[122] tends to linearly adjust the screw rod [114] in an extended forward
position relative to the adjuster pipe [112], however the screw rod [114 is
maintained in the retracted backward position by locking a linear movement of
the screw rod [114] relative to the adjuster pipe [112] with use of the nut
15
member [116]. The pre‐compressed main spring arrangement [122] provides
substantially stable and reliable spring action, between the screw rod [114] and
the adjuster pipe [112]. A structure and arrangement of the pre‐compressed
main spring arrangement [122] will now be explained in details hereinafter.
5 The pre‐compressed main spring arrangement [122] includes three spring
members, namely a first spring member [122a], a second spring member [122b],
and a third spring member [122c]. The first spring member [122a], a second
spring member [122b], and a third spring member [122c], are connected in series
with each other. For such purpose, a ring member is provided between ends of
10 two adjacent spring members to enable series connection of the first spring
member [122a], the second spring member [122b], and the third spring member
[122c], with each other. In assembly to the pre‐compressed main spring
arrangement [122], one end of the first spring member [122a] is connected to
the first adjuster end portion [112a] of the adjuster pipe [112], while other end
15 of the first spring member [122a] is connected to a first ring component. Further,
one end of the second spring member [122b] is connected to the first ring
component, while other end of the second spring member [122b] is connected
to a second ring component. Moreover, one end of the third spring member
[122c] is connected to the second ring component, while other end of the second
20 spring member [122b] is connected to the second screw end portion [114d] of
the screw rod [114]. With such arrangement, the first spring member [122a], the
second spring member [122b], and the third spring member [122b] are
connected in series with each other, and between the second screw end portion
[114d] of the screw rod [114] and the first adjuster end portion [112a] of the
25 adjuster pipe [112], for enabling sliding forward and backward movement of the
screw rod [114] relative to the adjuster pipe [112]. As three spring members
[122a, 122b, and 122c] connected in series are used, a relatively better/
increased spring force for same length of the pre‐compressed main spring
arrangement [122] is observed. Particularly, usage of such pre‐compressed main
16
spring arrangement [122] enables a relatively increased spring force on the
screw rod [114] for a defined length as compared to usage of a single spring.
Although, the spring pre‐compressed main spring arrangement [122] tends to
linearly adjust the screw rod [114] in an extended forward position relative to
5 the adjuster pipe [112], however the screw rod [114] is maintained in the
retracted backward position by locking a linear movement of the screw rod [114]
relative to the adjuster pipe [112], with use of the nut member [116]. In
particular, the nut member [116] may be suitably adjusted to restrict and/or
allow the linear movement of the screw rod [114] relative to the adjuster pipe
10 [112].
The nut member [116] is an elongated nut that includes an adjuster end portion
[116a], an engagement end portion [116b], and an internal threaded region
[116c]. The engagement end portion [116a] defines a first mating teeth [116d]
and a second mating teeth [116e], along an external periphery. The first mating
15 teeth [116d] is shaped and capable of engaging with the first engagement teeth
[104h] of the hollow piston rod [104b]. The second mating teeth [116e] is shaped
and capable of engaging with the second engagement teeth [104h] of the hollow
piston rod [104b]. Further, the nut member [116] is supported over the core
section [114a] of the screw rod [114], such that the internal threaded region
20 [116c] is in engagement with the external threaded region [114e] on the core
section [114a] of the screw rod [114]. Particularly, the nut member [116] is
supported, such that the engagement end portion [116b] is positioned within the
second end portion [104g] of the hollow piston rod [104b] while the adjuster end
portion [116] extends beyond the second end portion [104g] of the hollow piston
25 rod [104b] within the second adjuster end portion [112b] of the adjuster pipe
[112]. Engagement of either of the first mating teeth [116d] and the second
mating teeth [116e] with that of the first engagement teeth [104h] and the
second engagement teeth [104h] of the hollow piston rod [104b], corresponds to
restriction of a rotational movement of the nut member [116] and thus
17
corresponds to restriction of a linear movement of the screw rod [114] relative
to the adjuster pipe [114]. In such position, a stroke of the piston is termed as a
‘normal stroke’. Further, disengagement of both of the first mating teeth [116d]
and the second mating teeth [116e] with that of the first engagement teeth
5 [104h] and the second engagement teeth [104h] of the hollow piston rod [104b],
corresponds to allowing a rotational motion of the nut member [116] and thus
allowing a linear movement of the screw rod [114] relative to the adjuster pipe
[114]. In such position, a stroke of the piston is termed as a ‘slack adjustment
stroke’. Furthermore, the slack member [118] and the bearing component [124]
10 are provided to facilitate automatic engagement and/or disengagement of the
first mating teeth [116d] and the second mating teeth [116e] with that of the
first engagement teeth [104h] and the second engagement teeth [104h] of the
hollow piston rod [104b], for allowing and/or restricting a rotational movement
of the nut member [116] and thus allowing and/or restricting a linear movement
15 of the screw rod [114] relative to the adjuster pipe [114].
The slack member [118] is fixedly attached to the adjuster end portion [116a] of
the nut member [116], and is positioned within the adjuster pipe [112] facing the
slack adjustment end [112c] on the second adjuster end portion [112b] of the
adjuster pipe [112]. Although, the slack member [118] is defined as a separate
20 component fixedly attached to the adjuster end portion [116a] of the nut
member [116], it may be noted that the slack member [118] may be provided as
an integral component to the nut member [116]. A bearing component [124]
(interchangeably referred to as the ‘roller bearing [124]’) is provided between
the slack member [118] and the nut member [116], such that a portion of the
25 slack member [118] extends beyond the roller bearing [124]. Particularly, the
portion of the slack member [118] extends beyond the roller bearing [124], by a
small length. Further, a third resilient spring member [126] is provided between
slack member [118] and the second end portion [104g] of the hollow piston rod
[104b], for enabling resilient sliding forward and backward movement of the
18
slack member [118] relative to the hollow piston rod [104b]. Particularly, the
third resilient spring member [126] maintains the slack member [118] and the
nut member [116] to an extended forward position relative to the hollow piston
rod [104b]. In the extended forward position, the first slack member [118]
5 restricts rotational movement of the nut member [116] and thus restricts a linear
movement of the screw rod [114] relative to the adjuster pipe [114]. In the
retracted backward position, the first slack member [118] allows rotational
movement of the nut member [116] and thus allows a linear movement of the
screw rod [114] relative to the adjuster pipe [114].
10 With such arrangement of various components of the brake cylinder [100], dual
strokes of operation of the brake cylinder [100] is facilitated, namely the normal
stroke and the slack adjustment stroke. Notably, the brake cylinder [100]
automatically adjusts between the two strokes by a mechanical action, which will
be described later in details. In the normal stroke, either of the first mating teeth
15 [116d] and the second mating teeth [116e] of the nut member [116] engages
with the first engagement teeth [104h] and the second mating teeth [104i] of the
hollow piston rod [104], to restrict a rotational motion of the nut member [116]
relative to the screw rod [114] and thus restrict a linear movement of the screw
rod [114] relative to the nut member [116]. However, in the slack adjustment
20 stroke, neither of the first and second mating teeths [116d, 116e] of the nut
member [116] engages with the first and second engagement teeth [104e, 104f]
of the piston rod [104], to allow a rotational motion of the nut member [116]
relative to the screw rod [114] and thus allow a linear movement of the screw
rod [114] relative to the adjuster pipe [112].
25 Initial Arrangement for Operation
In operation, all the components of the brake cylinder [100] are initially in the
retracted position as shown in Fig. 1, with use of the first resilient spring member
[110], the second resilient spring member [120], the main spring arrangement
[122], and the third resilient spring member [126]. Also, initially, the brake
19
cylinder [100] is adjusted to operate in a normal stroke. Particularly, initially, the
first mating teeth [116d] of the nut member [116] is engaged to the first
engagement teeth [104h] of the hollow piston rod [104], such that a rotational
motion of the nut member [116] relative to the screw rod [114] and thus a linear
5 movement of the screw rod [114] relative to the adjuster pipe [112], is restricted.
The brake cylinder [100], as disclosed in the present disclosure, is required to
operate equally efficient in each of the 1) Normal Conditions; 2) Slack Increased
Conditions (as is shown in Figs. 2a‐2i); and 3) Slack Decreased Conditions (as is
shown in Figs. 3a‐3h). An operation of the brake cylinder in each of the
10 aforementioned conditions will be described in details hereinafter.
1. Normal Conditions
In the slack free conditions (also referred to as normal conditions), as is shown in
Fig. 1, the brake cylinder [100] operates entirely in the normal stroke only. In
such conditions, a distance between the second screw end portion [114d] of the
15 screw rod [114] and the wheel treads is ‘A’ distance only. Accordingly, during
braking, the brake cylinder [100] is required to expand by the ‘A+ES’ distance,
while during brake release, the brake cylinder [100] is required to retract by the
same ‘A+ES’ distance, for efficient braking.
1a. Braking Operation in Normal Conditions
20 For braking in the normal conditions, the pneumatic arrangement supplies air to
the brake cylinder [100] through the air delivery port [102d] of the housing [102].
The air is supplied to the piston face [104a] of the piston rod arrangement [104].
Moreover, the central hole [104d] in the piston face [104a] allows a portion of air
to pass therethrough and enter the internal cavity [104e] in the hollow piston
25 rod [104b], to exert the air pressure on the first screw end portion [114c] of the
screw rod [114]. Notably, in such conditions, the slack adjusting arrangement
[106] is inoperative. Particularly, the first mating teeth [116d] of the nut member
[116] is engaged to the first engagement teeth [104h] of the hollow piston rod
[104]. Therefore, in such conditions, a rotational movement of the nut member
20
[116] relative to the screw rod [114] and thus a linear movement of the screw
rod [114] relative to the adjuster pipe [112] is restricted. A supply of air at the
piston face [104a] of the hollow piston rod [104], in the normal conditions,
enables a combined forward movement (leftward movement) of the piston rod
5 arrangement [104], the screw rod [114], the nut member [116], the slack
member [118], and the roller bearing [124], relative to the adjuster pipe [112]
and the housing [102], for the ‘A’ distance. As the slack member [118] is
separated from the slack adjustment end [112c] on second adjuster end [112b]
of the adjuster pipe [112] by the ‘A’ distance, the slack member [118] is not
10 pushed against the slack adjustment end [112c] on the second adjuster end
[112b] of the adjuster pipe [112], and a continuous normal stroke of the brake
cylinder [100] is maintained in the normal conditions. In other words, this stroke
provides a forward movement action, by moving the second screw end portion
[114d] towards the wheel treads by the ‘A’ distance. Thereafter, upon receipt of
15 more air at the piston face [104a] of the piston rod arrangement [104], the
adjuster pipe [112] is further pushed along with the piston rod arrangement
[104], the screw rod [114], the nut member [116], the slack member [118], and
the roller bearing [124]. Particularly, a combined forward movement (leftward
movement) of the piston rod arrangement [104], the adjuster pipe [112], the
20 screw rod [114], the nut member [116], the slack member [118], and the roller
bearing [124], is enabled. This forward stroke provides a braking action, by
further pushing the second screw end portion [114d] into the wheel treads by
‘ES’ distance. A further compression of first resilient spring member [110] and
the second resilient spring member [120] is enabled, for the ‘ES’ distance.
25 Therefore, the second screw end portion [114d] of the screw rod [114] is moved
forward towards the wheel treads by the ‘A+ES’ distance, for braking in the
normal operating conditions, wherein the effective braking is ‘ES’ distance. In
such position, the first resilient spring member [110] is compressed by ‘A+ES’
distance, while the second resilient spring member [120] is compressed by ‘ES’
21
distance.
1b. Braking Release Operation in Normal Conditions
For brake release operation in the slack free conditions, the pneumatic
arrangement sucks back air from the brake cylinder [100] through the air delivery
5 port [102d] of the housing [102]. The air is sucked back from the piston face
[104] of the piston rod arrangement [104]. Moreover, air in the air internal cavity
[104e] of the hollow piston rod [104b] is also sucked back. In such conditions, the
slack adjusting arrangement [106] is inoperative. Particularly, the first mating
teeth [116d] of the nut member [116] is kept engaged to the first engagement
10 teeth [104h] of the hollow piston rod [104]. Therefore, in such condition a
rotational movement of the nut member [116] relative to the screw rod [114]
and thus a linear movement of the screw rod [114] relative to the adjuster pipe
[112] remains restricted. Therefore a release of air from the piston face [104a] of
the piston rod arrangement [104], in the slack free conditions, enables a
15 combined backward movement (rightward movement) of the hollow piston rod
[104], the adjuster pipe [112], the screw rod [114], the nut member [116], the
slack member [118], and the roller bearing [124] relative to the housing [102], by
‘ES’ distance. In particular, such backward movement is initiated due to the
spring actions of the first resilient spring member [110] and the second resilient
20 spring member [120], on the hollow piston rod [104] and the adjuster pipe [112]
respectively. This stroke provides a backward movement action, by moving the
second screw end portion [114d] away from the wheel treads by the ‘ES’
distance. Thereafter, upon further sucking back of more air from the piston face
[104a] of the piston rod arrangement [104], a combined rightward movement of
25 the hollow piston rod [104], the screw rod [114], the nut member [116], the slack
member [118], and the roller bearing [124], is enabled, by a ‘A’ distance. This
leftwards stroke is provided by the spring action of the first resilient spring
member [110] by the ‘A’ distance. Thus, the brake cylinder [100] is retracted
releasing brake from the wheel treads.
22
2. Slack Increased Conditions
In the slack increased operating condition, as is shown in Figs. 2a‐2i, an
additional slack distance, “W1”, may be observed due to wearing of the brake
shoes. In such conditions, as is shown in Fig. 2a, a distance between the second
5 screw end portion [114d] of the screw rod [114] and the wheel treads is ‘A1’
distance, which is particularly, ‘A+W1’ distance. During braking, the brake
cylinder [100] is required to expand by the ‘A+W1+ES’ distance, while during
brake release, the brake cylinder [100] is required to retract by the ‘A+W1+ES’
distance, for effective braking of ‘ES’ distance.
10 2a. Braking Operation in Slack Increased Conditions
For braking in the slack increased conditions, the pneumatic arrangement
supplies air to the brake cylinder [100] through the air delivery port [102d] of the
housing [102]. The air is supplied to the piston face [104a] of the piston rod
arrangement [104]. Moreover, the central hole [104d] in the piston face [104a]
15 allows a portion of air to pass therethrough and enter the internal cavity [104e]
in the hollow piston rod [104b], to exert the air pressure on the first screw end
portion [114c] of the screw rod [114]. Notably, in such conditions, the slack
adjusting arrangement [106] is inoperative, and the brake cylinder [100] is
initially required to follow the normal stroke. Particularly, the first mating teeth
20 [116d] of the nut member [116] is engaged to the first engagement teeth [104h]
of the hollow piston rod [104]. Therefore, in such condition a rotational
movement of the nut member [116] relative to the screw rod [114] and thus a
linear movement of the screw rod [114] relative to the adjuster pipe [112] is
restricted. A supply of air at the piston face [104a] of the hollow piston rod [104],
25 in the slack increased conditions, initially enables a combined forward movement
(leftward movement) of the hollow piston rod [104], the screw rod [114], the nut
member [116], the slack member [118], and the roller bearing [124], relative to
the housing [102], for the ‘A’ distance. This stroke provides a forward movement
action, by moving the second screw end portion [114d] towards the wheel treads
23
by the ‘A’ distance. A compression of the first resilient spring member [110] is
thus enabled, for a compression of ‘A’ distance.
After moving the “A” distance, the extra pressure on the first end portion [104f]
of the hollow piston rod [104], causes the slack member [118] to be pushed
5 against the slack adjustment end [112c] on the second adjuster end [112b] of the
adjuster pipe [112]. This causes a slight backward movement (by a distance “X’)
of the slack member [118] and the nut member [116], which causes
disengagement of the first mating teeth [116d] of the nut member [116] from
the first engagement teeth [104h] of the hollow piston rod [104]. Such action
10 causes small compression of the third resilient spring by the ‘X’ distance. Thus,
the brake cylinder [100] is adjusted to operate in the slack adjustment stroke. In
the slack adjustment stroke, a rotational motion of the nut member [116] on the
screw rod [114] and the linear forward movement of the screw rod [114] relative
to the adjuster pipe [112] is allowed. As the main spring arrangement [122] is
15 pre‐compressed, it has a tendency to expand the screw rod [114] relative to the
adjuster pipe [112]. Therefore, in the slack adjustment stroke of the brake
cylinder [100], the combination of the air pressure on the second screw end
portion [114b] of the screw rod [114] and the spring force of the three spring
members [122a, 122b, and 122c] of the main spring arrangement [122] causes
20 forward movement of the screw rod [114] relative to the adjuster pipe [112], by
the slack distance ‘W1’. Since a combination of the air pressure and the spring
force of three spring members (122a, 122b, and 122c) is used herein for forward
movement of the screw rod [114] relative to the adjuster pipe [112], a relatively
quicker and efficient adjustment of the screw rod [114] relative to the adjuster
25 pipe [112], for the slack distance ‘W1’ is attained. Therefore, total expansion of
the brake cylinder [100] is ‘A+W1’ distance. Moreover, as the three serially
connected spring members [122a, 122b, and 122c] are used herein, the required
expansion force is achieved with reduced length of the double concentric spring
[122] as compared to single spring.
24
Thereafter, upon expanding by the ‘A+W1’ distance, the air pressure on the
piston face [104a] of the piston rod arrangement [104], is further increased. This
causes the hollow piston rod [104] to linearly move relative to the nut member
[116] (denoted by ‘TE’ stroke). This forward movement of the hollow piston rod
5 [104] causes engagement of the second mating teeth [116e] of the nut member
[116] with the second engagement teeth [104i] of the hollow piston rod [104].
Therefore, the brake cylinder [100] is switched back from the slack adjusting
stroke of operation to the normal stroke. Thus, a rotational motion of the nut
member [116] relative to the screw rod [114] and thus a linear movement of the
10 screw rod [114] relative to the nut member [116], is again restricted.
Thereafter, upon receipt of more air at the first end portion [104f] of the hollow
piston rod [104], the adjuster pipe [112] is further pushed along with the piston
rod arrangement [104], the screw rod [114], the nut member [116], the slack
member [118], and the roller bearing [124]. Particularly, a combined leftward
15 movement of the hollow piston rod [104], the adjuster pipe [112], the screw rod
[114], the nut member [116], the slack member [118], and the roller bearing
[124], is enabled. This forward stroke provides a braking action, by further
pushing the second screw end portion [114d] into the wheel treads by ‘ES’
distance. A further compression of the first resilient spring member [110] and
20 the second resilient spring member [120] is enabled, for the ‘ES’ distance.
Therefore, the total expansion of the brake cylinder [100] is “A1+ES” distance,
which is “A+W+ES” distance, for braking in the normal operating conditions,
wherein the effective braking is ‘ES’ distance. In such conditions, the first
resilient spring member [110] is compressed by ‘A+ES’ distance, the second
25 resilient spring member [120] is compressed by ‘ES’ distance, the third resilient
spring member [120] is compressed by ‘TE’ distance.
2b. Braking Release Operation in Slack Increased Conditions
For brake release operation in the slack increased conditions, the pneumatic
arrangement sucks back air from the brake cylinder [100] through the air delivery
25
port [102d] of the housing [102]. The air is sucked back from the piston face
[104] of the piston rod arrangement [104]. Moreover, air in the air internal cavity
[104e] of the hollow piston rod [104b] is also sucked back. In such conditions, the
slack adjusting arrangement [106] is inoperative. Particularly, the second mating
5 teeth [116e] of the nut member [116] is kept engaged to the second engagement
teeth [104i] of the hollow piston rod [104]. Therefore, in such conditions, a
rotational movement of the nut member [116] relative to the screw rod [114]
and thus a linear movement of the screw rod [114] relative to the adjuster pipe
[112] remains restricted. Therefore, a release of air from the piston face [104a]
10 of the piston rod arrangement [104], in the slack increased operating conditions,
enables a combined backward movement of the hollow piston rod [104], the
adjuster pipe [112], the screw rod [114], the nut member [116], the slack
member [118], and the roller bearing [124] relative to the housing [102].
Notably, this is done due to the spring actions of the first resilient spring member
15 [110] and the second resilient spring member [120], on the hollow piston rod
[104] and the adjuster pipe [112] respectively. This backward stroke provides a
backward movement action, by moving the second screw end portion [114d]
away from the wheel treads by the ‘ES’ distance. Thereafter, upon sucking back
of more air from the piston face [104a] of the piston rod arrangement [104],
20 spring action of the third resilient spring member [126] causes forward
movement of the nut member [116] relative to the hollow piston rod [104]. This
causes disengagement of the second mating teeth [116e] of the nut member
[116] from the second engagement teeth [104i] of the hollow piston rod [104],
and engagement of the first mating teeth [116d] of the nut member [116] to the
25 first engagement teeth [104h] of the hollow piston rod [104]. This maintains the
brake cylinder [100] in the normal stroke, and no slack adjustment stroke is
observed. Thereafter, upon further sucking back of more air from the piston face
[104a] of the piston rod arrangement [104], a combined backward movement of
the hollow piston rod [104], the screw rod [114], the nut member [116], the slack
26
member [118], and the roller bearing [124], is enabled by the “A’ distance. This
leftwards stroke is provided by the spring action of the first resilient spring
member [110] by the ‘A’ distance. Thus, the brake cylinder [100] is retracted by
the “A’ distance, releasing brake from the wheel treads. Thereby, the second
5 screw end portion [114b] of the screw rod [114] is maintained at the ‘A’ distance
apart from the wheel treads, after end of the brake release operations in the
slack increased conditions.
3. Slack Decreased Conditions
In the slack decreased operating condition, as is shown in Figs. 3a‐3h, negative
10 slack of the slack distance ‘W2’, may be observed due to replacement of the
brake shoes with new brake shoes. In such conditions, as is shown in Fig. 3a, a
distance between the second screw end portion [114d] of the screw rod [114]
and the wheel treads is ‘A2’ distance, which is particularly, ‘A‐W2’ distance.
During braking, the brake cylinder [100] is required to expand by the ‘A‐W2’
15 distance, while during brake release, the brake cylinder [100] is required to
retract by the ‘A’ distance.
3a. Braking Operation in Slack Decreased Conditions
For braking in the slack decreased operating conditions, the pneumatic
arrangement supplies air to the brake cylinder [100] through the air delivery port
20 [102d] of the housing [102]. The air is supplied to the piston face [104a] of the
piston rod arrangement [104]. Moreover, the central hole [104d] in the piston
face [104a] allows a portion of air to pass therethrough and enter the internal
cavity [104e] in the hollow piston rod [104b], to exert the air pressure on the first
screw end portion [114c] of the screw rod [114]. Notably, in such conditions, the
25 slack adjusting arrangement [106] is inoperative, and the brake cylinder [100] is
initially required to follow a normal stroke. Particularly, the first mating teeth
[116d] of the nut member [116] is engaged to the first engagement teeth [104h]
of the hollow piston rod [104]. Therefore, in such condition a rotational
movement of the nut member [116] relative to the screw rod [114] and thus a
27
linear movement of the screw rod [114] relative to the adjuster pipe [112] is
restricted. Therefore a supply of air at the first end portion [104f] of the hollow
piston rod [104], in the slack decreased operating conditions, initially enables a
combined leftward movement of the hollow piston rod [104], the screw rod
5 [114], the nut member [116], the slack member [118], and the roller bearing
[124], relative to the housing [102]. This leftwards stroke provides a forward
movement action, by moving the second screw end portion [114d] towards the
wheel treads by the ‘A2’ distance (‘A‐W2’ distance). A compression of the first
resilient spring member [110] is thus enabled, for a compression of ‘A2’ distance
10 (‘A‐W2’ distance). Notably, a premature stop of the combination of the hollow
piston rod [104], the screw rod [114], the nut member [116], the slack member
[118], and the roller bearing [124], relative to the housing [102] is observed, due
to premature stop of the second screw end portion [114b] of the screw rod [114]
against the wheel treads.
15 After moving a distance of ‘A2’, the extra pressure on the first end portion [104f]
of the hollow piston rod [104], causes the slack member [118] to be pushed
against the second adjuster end [112b] of the adjuster pipe [112]. This causes a
slight backward movement (by a distance “X’) of the slack member [118] and the
nut member [116], which causes disengagement of the first mating teeth [116d]
20 of the nut member [116] from the first engagement teeth [104h] of the hollow
piston rod [104]. Such action causes small compression of the third resilient
spring. Thus, the brake cylinder [100] is required to operate in the slack
adjustment stroke. In the slack adjustment stroke, a rotational motion of the nut
member [116] on the screw rod [114] and the linear movement of the screw rod
25 [114] relative to the adjuster pipe [112] is allowed. Notably, the second screw
end portion [114b] of the screw rod [114] is still prematurely stopped against the
wheel treads.
As the double concentric spring [122] is pre‐compressed, it has a tendency to
expand when set free. However, as the second screw end portion [114b] of the
28
screw rod [114] is still prematurely stopped against the wheel treads, a forward
movement of the screw rod [114] relative to the adjuster pipe [112] is restricted.
With further pressure on the first end portion [104f] of the hollow piston rod
[104], the combination of the piston rod [104], the nut member [116], and the
5 slack member [118] is moved forward in the forward direction, relative to the
screw rod [114] and the housing [102]. This causes compression/ retraction of
the screw rod [114] relative to the adjuster pipe [112], by the slack distance
“W2’. This compresses the main spring arrangement [122], by the slack distance
“W2”. Therefore, the total expansion of the brake cylinder [100] is maintained at
10 ‘A2’ distance, which is given by ‘A‐W’ distance.
Thereafter, upon expanding by the ‘A‐W’ distance, the air pressure on the face of
the first end portion [104f] of the piston rod [104], is further increased. This
causes the hollow piston rod [104] to linearly move relative to the nut member
[116] (denoted by ‘TE’ stroke). This forward movement of the hollow piston rod
15 [104] causes engagement of the second mating teeth [116e] of the nut member
[116] with the second engagement teeth [104i] of the hollow piston rod [104].
Therefore, the brake cylinder [100] is switched back from the slack adjusting
stroke of operation to normal stroke of operation. Thus, a rotational motion of
the nut member [116] relative to the screw rod [114] and thus a linear
20 movement of the screw rod [114] relative to the nut member [116], is restricted.
Thereafter, upon receipt of more air at the first end portion [104f] of the hollow
piston rod [104], the adjuster pipe [112] is further pushed along with the piston
rod arrangement [104], the screw rod [114], the nut member [116], the slack
member [118], and the roller bearing [124]. Particularly, a combined leftward
25 movement of the hollow piston rod [104], the adjuster pipe [112], the screw rod
[114], the nut member [116], the slack member [118], and the roller bearing
[124], is enabled. This forward stroke provides a braking action, by further
pushing the second screw end portion [114d] into the wheel treads by ‘ES’
distance. A further compression first resilient spring member [110] and the
29
second resilient spring member [120] is enabled, for the ‘ES’ distance. Therefore,
the total expansion of the brake cylinder [100] is “A2+ES” distance, which is “A‐
W2+ES” distance, for braking in the normal operating conditions, wherein the
effective braking is ‘ES’ distance. In such conditions, the first resilient spring
5 member [110] is compressed by ‘A+ES’ distance, the second resilient spring
member [120] is compressed by ‘ES’ distance, the third resilient spring member
[120] is compressed by ‘TE’ distance.
3b. Braking Release Operation in Slack Decreased Conditions
For brake release operation in the slack decreased conditions, the pneumatic
10 arrangement sucks back air from the brake cylinder [100] through the air delivery
port [102d] of the housing [102]. The air is sucked back from the piston face
[104] of the piston rod arrangement [104]. Moreover, air in the air internal cavity
[104e] of the hollow piston rod [104b] is also sucked back. In such conditions, the
slack adjusting arrangement [106] is inoperative. Particularly, the second mating
15 teeth [116e] of the nut member [116] is kept engaged to the second engagement
teeth [104i] of the hollow piston rod [104]. Therefore, in such condition, a
rotational movement of the nut member [116] relative to the screw rod [114]
and thus a linear movement of the screw rod [114] relative to the adjuster pipe
[112] remains restricted. Therefore, a release of air from the piston face [104a]
20 of the piston rod arrangement [104], in the slack decreased conditions, enables a
combined backward movement of the hollow piston rod [104], the adjuster pipe
[112], the screw rod [114], the nut member [116], the slack member [118], and
the roller bearing [124] relative to the housing [102]. Notbaly, this is done due to
the spring actions of the first resilient spring member [110] and the second
25 resilient spring member [120], on the hollow piston rod [104] and the adjuster
pipe [112] respectively. This backward stroke provides a backward movement
action, by moving the second screw end portion [114d] away from the wheel
treads by the ‘ES’ distance. Thereafter, upon sucking back of more air from the
piston face [104a] of the piston rod arrangement [104], spring action of the third
30
resilient spring member [126] causes leftwards movement of the nut member
[116] relative to the hollow piston rod [104]. This causes disengagement of the
second mating teeth [116e] of the nut member [116] from the second
engagement teeth [104i] of the hollow piston rod [104], and engagement of the
5 first mating teeth [116d] of the nut member [116] from the second engagement
teeth [104h] of the hollow piston rod [104]. This maintains the brake cylinder
[100] in the normal stroke, and no slack adjustment stroke is observed.
Thereafter, upon further sucking back of more air from the piston face [104a] of
the piston rod arrangement [104], a combined rightward movement of the
10 hollow piston rod [104], the screw rod [114], the nut member [116], the slack
member [118], and the roller bearing [124], is enabled by the “A’ distance. This
leftwards stroke is provided by the spring action of the first resilient spring
member [110] by the ‘A’ distance. Thus, the brake cylinder [100] is retracted by
the “A’ distance, releasing brake from the wheel treads. Thereby, the second
15 screw end portion [114b] of the screw rod [114] is maintained at the ‘A’ distance
apart from the wheel treads, after end of the brake release operations in the
slack increased conditions.
Such structure, arrangement, and system of the brake cylinder [100] has
numerous advantages. One of such advantage of the present invention is to
20 provide the slack adjusting arrangement [106], which provides for expansion of
the brake cylinder [100] by a ‘A+ES’ distance in the slack free operating
conditions, by a ‘A+W1+ES’ distance in the slack increased operating conditions,
by a ‘A‐W2+ES’ distance in slack decreased operating conditions, thereby
adjusting for the slack distances ‘W1’ and ‘W2’, observed between the brake
25 cylinder [100] and the wheel treads, in the slack increased condition and the
slack decreased condition, respectively. Accordingly, consistent and effective
braking of ‘ES’ distance is observed in each of the normal condition, the slack
increased condition, and the slack decreased condition.
Another advantage of the disclosed brake cylinder [100] includes positioning of
31
the slack adjusting arrangement [106] within the housing [102], as part of the
brake cylinder [100]. As the slack adjusting arrangement [106] is positioned
within he housing [102], an overall construction of BMBS is relatively less
complex, less cumbersome, and more compact. Moreover, as the slack adjusting
5 arrangement [106] is positioned within he housing [102], it is protected from
external environment, which makes the brake cylinder [100] more rugged, more
robust, and more reliable.
Yet another advantage of the disclosed brake cylinder [100] includes
employment of the main spring arrangement [122] as part of the slack adjusting
10 arrangement [106]. The main spring arrangement [122] provides for expansion of
the screw rod [112] with an appropriate force relative to the adjuster pipe [112],
without a need of single long spring. The main spring arrangement [122] employs
three spring members [122a, 122b, and 122c]connected in series with each
other, for spring effort, for expansion of the screw rod [112] relative to the
15 adjuster pipe [112], which provides more force than a single elongated spring of
a length of combination of the three spring members [122a, 122b, and 122c].
This makes the adjusting arrangement [106] and thus the brake cylinder [100]
relatively more compact in size. Therefore, such brake cylinder [100] utilizes less
space on the train.
20 Further, the force required for expansion of the screw rod [112] with an
appropriate force relative to the adjuster pipe [112] by the main spring
arrangement [122], is also supported by the air pressure on the face of the first
screw end portion [114c] of the screw rod [114]. Particularly, a force on the
screw rod [114] to expand relative to the adjuster pipe [112] is given by a
25 combined force of the spring force of the main spring arrangement [122] and the
air pressure on the face of the first screw end portion [114c] of the screw rod
[114]. The central hole [104d] in the piston face [104a] allows a portion of air to
enter the internal cavity [104e] of the hollow piston rod [104b] and thus apply
the pressure on the first screw end portion [114c] of the screw rod [114]. Such
32
air pressure provides the additional force on the screw rod [114] for shootingly
expand the screw rod [114] relative to the adjuster pipe [112].
While the preferred embodiments of the present invention have been described
hereinabove, it should be understood that various changes, adaptations, and
5 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
forms without departing from its spirit or essential characteristics. The described
embodiments are to be considered in all respects only as illustrative and not
10 restrictive.
List of Components:
100 – Brake Cylinder
102 – Housing
102a – First Housing Portion of 102
15 102b – Second Housing Portion of 102
102c – Internal Step of 102
102d – Air Delivery Port of 102
102e – Piston Guide Cavity of 102
102f – Indicator Cavity of 102
20 104 – Hollow Piston Rod of 102
104a – Piston Face of 104
104b – Hollow Piston Rod of 104
104c – Guide Portion of 104
104d – Central Hole of 104
25 104e – Internal Cavity of 104
104f – First End Portion of 104
104g – Second End Portion of 104
104h – First Inner Engagement Teeth
104i – Second Inner Engagement Teeth
33
106 – Slack Adjusting Arrangement
108 – Indicator Rod
110 – First Resilient Spring Member of 106
112 – Adjuster Pipe of 106
5 112a – First Adjuster End Portion of 112
112b – Second Adjuster End Portion of 112
112c – Slack Adjustment End
114 – Screw Rod of 106
114a – Core Section of 114
10 114b – External Section of 114
114c – First Screw End Portion of 114
114d – Second Screw End Portion of 114
114e – External Threaded Region
116 – Nut Member of 106
15 116a – Adjuster End portion of 116
116b – Engagement End Portion of 116
116c – Internal Threaded Region of 116
116d – First Mating Teeth of 116
116e – Second Mating Teeth of 116
20 118 – Slack Member of 106
120 – Second Resilient Spring Member
122 – Pre‐compressed Double Concentric Spring
122a – First Spring Member of 122
122b – Second Spring Member of 122
25 122c – Third Spring Member of 122
124 – Roller Bearing
126 – Third Resilient Spring Member
34

We Claim:
1. A brake cylinder [100] for a bogie mounted brake system (BMBS) of a train,
comprising:
‐ a housing [102];
5 ‐ a piston rod arrangement [104] slideably arranged relative to and
extending within the housing [102], the piston arrangement [104]
including a piston face [104a] with a central hole [104d], and a hollow
piston rod [104b] with at least two engagement teeth [104h, 104i];
and
10 ‐ a slack adjusting arrangement [106], including:
an adjuster pipe [112] resiliently slideably arranged relative to and
extending within the housing [102], while housing at least a
portion of the hollow piston rod [104];
a screw rod [114] resiliently slideably arranged relative to the
15 adjuster pipe [112] and extending at least partially through the
hollow piston rod [104] and the adjuster pipe;
a pre‐compressed main spring arrangement [122] including a
plurality of springs connected in series with each other and
positioned between the screw rod [114] and the adjuster pipe
20 [112], for enabling resilient sliding arrangement therebetween;
and
a nut member [116] threadably engaged to the screw rod [114]
and positioned within the hollow piston rod [104b] of the piston
arrangement [104], and including an engagement end portion
25 [116b] that includes at least two mating teeth [116d, 116e]
capable of engaging with the at least two engagement teeth
[104h, 104i] of the hollow piston rod [104b], wherein
in a normal stroke, a linear movement of the screw rod
[114] relative to the adjuster pipe [112] is restricted, by
35
engaging either of the at least two mating teeth [116d,
116e] of the nut member [116] with the at least two
engagement teeth [104h, 104i] of the hollow piston rod
[104],
5 in a slack adjustment stroke, a linear movement of the
screw rod [114] relative to the adjuster pipe [112] is
allowed, by disengaging each of the at least two mating
teeth [116d, 116e] of the nut member [116] from the at
least two engagement teeth [104h, 104i] of the hollow
10 piston rod [104], thereby enabling the screw rod [114] to
be linearly adjusted relative to the adjuster pipe [112] by
the slack distance.
2. The brake cylinder [100] as claimed in claim 1, wherein in a slack increased
conditions of the brake cylinder [100], the screw rod [114] is moved
15 forward relative to the adjuster pipe [112] by the slack distance [W1], in
the slack adjusting stroke.
3. The brake cylinder [100] as claimed in claim 1, wherein in a slack decreased
conditions of the brake cylinder, the screw rod [114] is moved backward
relative to the adjuster pipe [112] by the slack distance [W2], in the slack
20 adjusting stroke.
4. The brake cylinder [100] as claimed in claim 1, wherein the central hole
[104d] in the piston face [104a] of the piston rod arrangement [104] allows
a portion of air on the piston face [104a] to enter within the hollow piston
rod [104b] and exert an air pressure on a first screw end portion [114c] of
25 the screw rod [114].
5. The brake cylinder [100] as claimed in claim 1, claim 2, and claim 3, a
combination of the air pressure on the first screw end portion [114c] of the
screw rod [114] and a spring force of the main spring arrangement [122]
corresponds to the forward movement of the screw rod [114] relative to
36
the adjuster pipe [112] by the slack distance [W1], in the slack adjusting
stroke.
6. The brake cylinder [100] as claimed in claim 1, wherein the piston rod
arrangement [104] defines a first end portion [104f] at the piston face
5 [104a] and a second end portion [104g] at the hollow piston rod [104b],
such that the at least two engagement teeth [104h, 104i] are defined on
the second end portion [104g] of the piston rod arrangement [104].
7. The brake cylinder [100] as claimed in claim 1 and claim 6, wherein the
adjuster pipe [112] houses the second end portion [104g] of the piston rod
10 arrangement [104] proximal to a slack adjustment end [112b].
8. The brake cylinder [100] as claimed in claim 1, wherein the nut member
[116] includes an engagement end portion [116b] facing the slack
adjustment end [112b] of the adjuster pipe [112], the engagement end
portion [116b] including the at least two external mating teeth [116d,
15 116e] and positioned within the second end portion [104g] of the piston
rod arrangement [104], and an internal threaded region [116c] in threaded
engagement with the screw rod [114].
9. The brake cylinder [100] as claimed in claim 1 and claim 8, wherein the
slack adjusting arrangement [106] further includes a slack member [118]
20 connected to the adjuster end portion [116a] of the nut member [116].
10. The brake cylinder [100] as claimed in claim 9, wherein the slack adjusting
arrangement [106] further includes a bearing component [124] positioned
between the slack member [118] and the screw rod [114], such that a
portion of the slack member [118] extends beyond the bearing component
25 and faces the slack adjustment end of the adjuster pipe [112].
11. The brake cylinder [100] as claimed in claim 9, wherein the adjuster pipe
[112], the piston rod arrangement [104], and the nut member [116] are
positioned within the housing [102], while the screw rod [114] is at least
partially positioned within the housing [102].
37
12. The brake cylinder [100] as claimed in claim 1, further comprises a first
resilient spring member [110] arranged between the piston rod
arrangement [104] and the housing [102], to resiliently facilitate a sliding
movement of the piston rod arrangement [104] relative to the housing
5 [102].
13. The brake cylinder [100] as claimed in claim 1, further comprises a second
resilient spring member [120] arranged between the adjuster pipe [112]
and the housing [102], to resiliently facilitate a sliding movement of the
adjuster pipe [112] relative to the housing [102].
10 14. The brake cylinder [100] as claimed in claim 1, further comprises a third
resilient spring member [126] arranged between the slack member [118]
and the second end portion [104g] of the piston rod arrangement [104], to
resiliently facilitate engagement and disengagement of the at least two
mating teeth [116d, 116e] of the nut member [116] with the at least two
15 engagement teeth [104e, 104f] of the hollow piston rod [104].
15. The brake cylinder [100] as claimed in claim 1, further comprises a rubber
bellow arranged on at least a portion of an outer periphery of the housing
[102], for protection of the piston rod arrangement [104] and the slack
adjusting arrangement [106].
20 16. The brake cylinder [100] as claimed in claim 1, wherein the housing [102]
comprises a piston guiding cavity [102e] through which at least a portion of
the piston rod arrangement [104] passes, to ensure proper sliding
movement of the piston rod arrangement [104] relative to the housing
[102].
25 17. The brake cylinder [100] as claimed in claim 1, further comprises an
indicator rod [108] attached to the piston rod arrangement [104] and at
least partially housed within the housing [102], such that at least another
portion the indicator rod [108] extends outside the housing [102]
corresponding to a sliding movement of the piston rod arrangement [104]
38
relative to the housing [102].
18. The brake cylinder [100] as claimed in claim 1, is suitably attached to a
brake arrangement, such that predetermined extension and retraction of
the brake cylinder [100] corresponds to braking operation and brake
5 release operation on the wheels of a wagon of the train.