Note: Descriptions are shown in the official language in which they were submitted.
CA 02837576 2013-12-18
BRAKE BEAM PADDLE CAPS
BACKGROUND OF THE INVENTION
[0001] The subject matter herein relates to a railway car truck and,
more particularly, to a brake beam assembly for a railway car truck.
[0002] In a railway car truck, two axles are held in a pair of laterally
spaced side frames, with a bolster extending laterally between and supported
on each
side frame. The wheels are press fit on the axles, with the ends of the axles
also fitted
with a roller bearing assembly. The roller bearing assembly is fit into a
bearing
adapter that is fit into a pedestal jaw opening at the longitudinal end of
each side
frame. Each railway car truck also includes a braking system having two brake
beams
that act to transmit braking force through brake shoes to the outer tread of
the railway
wheels. The brake beams are attached to the side frames in corresponding guide
brackets having wear liners therein. For example, paddles extending from ends
of the
brake beams are received in the wear liners and are movable therein during
application of the braking system. Typically, wear plates are positioned
within the
guide brackets to eliminate wear on the guide brackets.
[0003] During operation, the wear plates deteriorate over time. For
example, the friction between the paddles and the wear liners eventually cause
the
wear plates to need replacement. Replacement of the wear liners requires the
railway
car truck to be taken off line and disassembled. The paddles are typically
made from
a hard material, such as a cast steel that wears over time against the wear
plates. To
protect the paddles, the paddles are typically flame hardened to prevent wear
on the
paddles. Such process adds to the overall cost of manufacture of the brake
beam
assembly and to the overall manufacture time of the brake beam assembly.
Additionally, over time the paddles themselves may need replacement.
[0004] A need exists for an improved railway car truck that can
reduce the friction and wear between the brake beam assembly and the wear
liners
held by the side frames.
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BRIEF DESCRIPTION OF THE INVENTION
[0005] In one embodiment, a brake beam assembly for a railway car
truck is provided that includes a brake beam configured to be mounted between
opposed side frames of the railway car truck, a strut extending from the brake
beam
and brake heads coupled to the brake beam proximate to right hand and left
hand ends
thereof. Each brake head holds a brake shoe configured to engage a wheel of
the
railway car truck. Paddles extend exterior of the brake heads. The paddles
have
distal ends received in corresponding guide brackets of the side frames to
guide
movement of the brake beam. Paddle caps cover the distal ends of the paddles.
The
paddle caps are configured to be received in brake beam wear liners in
corresponding
side frames of the railway car truck. The paddle caps have a lower coefficient
of
friction than the paddles.
[0006] In another embodiment, a railway car truck is provided
having a bolster having laterally opposite ends and two side frames transverse
to the
bolster and supporting the opposite ends of the bolster. Each side frame has a
guide
bracket on an inner side of the side frame. Brake beam wear liners are
received in
corresponding guide brackets on the side frames. The brake beam wear liners
each
have a pocket. A brake beam assembly is supported on the bolster and side
frames.
The brake beam assembly includes a brake beam mounted between the side frames,
a
strut extending from the brake beam and brake heads coupled to the brake beam.
Each brake head holds a brake shoe configured to engage a wheel of the railway
car
truck. Paddles are provided at opposite ends of the brake beam assembly. The
paddles are received in corresponding guide brackets to guide movement of the
brake
beam. Paddle caps cover the paddles and are received in pockets of
corresponding
wear liners. The paddle caps have a lower coefficient of friction than the
paddles.
[0007] Optionally, the paddle caps reduce the friction and wear on
the brake beam wear liner as compared to the paddles wearing on the brake beam
wear liners. The paddle caps may surround the paddles to ensure that the
paddles do
not engage the brake beam wear liners. The paddle caps may be manufactured
from a
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material having a substantially similar coefficient of friction as the brake
beam wear
liner. The paddle caps may be manufactured from the same material as the brake
beam wear liner.
[0008] Optionally, each paddle cap may include a top, a bottom, and
a distal end. Each brake beam wear liner may include an upper surface, a lower
surface and a base defining the corresponding pocket. The paddle cap may be
received in the brake beam wear liner such that the top faces the upper
surface, the
bottom faces the lower surface and the distal end faces the base.
[0009] Optionally, each paddle cap may have a cavity that receives a
distal end of the corresponding paddle. The paddle caps may be held on the
paddles
by an interference fit. Each paddle cap may include rounded edges and corners
facing
the brake beam wear liner. An exterior surface of each paddle cap may engage
the
corresponding brake beam wear liner to guide movement of the paddles. The
paddle
caps may take up a portion of a gap between the paddle and the brake beam wear
liner.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] Figure 1 is a side view of a railway car truck formed in
accordance with an exemplary embodiment;
[0011] Figure 2 is a top view of the railway car truck shown in
Figure 1;
[0012] Figure 3 is a perspective view of the railway car truck shown
in Figure 1;
[0013] Figure 4 is a side view of a portion of the railway car truck;
[0014] Figure 5 is a top, partial sectional view of a portion of the
railway car truck;
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[0015] Figure 6 illustrates a portion of the brake beam assembly
showing a paddle cap poised for loading onto a corresponding paddle of the
brake
beam assembly.
DETAILED DESCRIPTION OF THE INVENTION
[0016] Referring now to Figures 1-3, a railway car truck 10 is shown.
The railway car truck 10 includes two laterally spaced side frames 12 and 14,
between
which a bolster 16 extends. Each of the side frames 12, 14 and bolster 16 are
usually
a cast steel unitary structure. Various internal ribs and supports lend
strength, along
with a savings in overall weight for each of such cast steel truck components.
[0017] Axles 20 and 22 extend laterally between the side frames 12,
14. Railway wheels 24 are press fit on the ends of the axles 20, 22. Roller
bearing
assemblies 26 are also provided on the ends of the axles 20, 22. The side
frames 12,
14 include side frame openings 28 aligned with the bolster 16.
[0018] The bolster 16 includes bolster ends 32 and 34, which extend
through the side frame openings 28. Spring groups 36 support the bolster ends
32 on
a side frame lower support 42. The side frames 12, 14 include vertical columns
44
that are longitudinally spaced and form the side frame openings 28
therebetween. The
lower support section 42 has various raised structures adapted to position the
spring
group 36 thereupon.
[0019] The side frames 12, 14 include laterally spaced pedestal jaws
46 which are the further most lateral extent of the side frames 12, 14. Each
pedestal
jaw 46 forms a pedestal jaw opening 48, which is defined by a roof section 50,
an
outer wall 52, and an inner wall 54. The pedestal jaw opening 48 is adapted to
receive a bearing adapter 56 therein. The bearing adaptors 56 rest on the
roller
bearing assemblies 26.
[0020] The railway car truck 10 includes a brake system 60 having
brake heads 62 that support brake shoes 64. The brake system 60 is operated to
press
the brake shoes 64 against the railway wheels 24. The brake heads 62 may be
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fabricated or cast steel devices. The brake system 60 is supported from the
side
frames 12, 14 and the bolster 16 and is illustrated with additional reference
to Figure
4.
[0021] The bolster 16 includes on its upper surface a bolster center
plate 66, which includes a bolster center plate wear liner 68. Also included
on the
upper surface of the bolster 16 is a pair of laterally spaced side bearings
70.
[0022] Figure 4 is a side view of a portion of the railway car truck 10
illustrating a portion of an inner side 80 of the side frame 14. The side
frame 14
includes guide brackets 82 extending inward from the side frame 14.
Optionally, the
guide brackets 82 are integrally formed with the side frame 14. The guide
brackets 82
are positioned along the vertical column 44 proximate to the side frame
opening 28.
The guide brackets 82 are positioned proximate to the lower support section 42
on
each side of the side frame opening 28. Similarly, the side frame 12 (shown in
Figures 2 and 3) includes a pair of guide brackets that are substantially
similar to the
guide brackets 82.
[0023] Each guide bracket 82 includes a pocket 84 that is surrounded
by an upper wall 86 and a lower wall 88. The upper and lower walls 86, 88 are
substantially parallel to one another and project from the side frame 14 to
define the
pocket 84. In an exemplary embodiment, the guide bracket 82 has an open side
furthest from the side frame 14 that provides access to the pocket 84. The
open side
extends between the upper and lower walls 86, 88. The pocket 84 receives a
brake
beam wear liner 90 which receives a portion of the brake system 60 (shown in
Figure
3). For example, the brake beam wear liners 90 receive paddles 120 and paddle
caps
122 of the brake system 60 as described in further detail below. In an
exemplary
embodiment, the guide brackets 82 may conform to AAR standard S-366. The AAR
standards call for the guide bracket 82 to be inclined to the horizontal at an
angle of
14 for 40, 50, 70, and 90-100 ton cars, and at an angle of 16 for 125 ton
cars.
[0024] The brake beam wear liners 90 each include a pocket 92
defined by an upper surface 94, a lower surface 96 and a base 98 at the
interior of the
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pocket 92. The brake beam wear liners 90 protect wear on the guide brackets
82. The
break beam wear liners 90 are replaceable once worn, such as by removing the
break
beam wear liners 90 from the guide brackets 82 and inserting new break beam
wear
liners 90 therein. However, the railway car truck 10 must be taken out of
service for
such repair. Reducing wear on the break beam wear liners 90 reduces the
frequency
of replacement allowing longer service life for the railway car truck 10.
[0025] In an exemplary embodiment, each brake beam wear liner 90
is manufactured from a metal material, such as a cast steel material. Other
types of
metal materials may be used in alternative embodiments. A metal material used
for
the brake beam wear liner 90 may be manufactured by a process other than
casting,
such as stamping and forming the brake beam wear liner 90. Alternatively, the
brake
beam wear liner 90 may be fabricated from a synthetic material, such as a
nylon
material, a high molecular weight polyethylene material, and the like.
Optionally,
impact resistant synthetic materials may be used. Other types of synthetic
materials
may be used in alternative embodiments. The break beam wear liner 90 may be
manufactured from a material selected to provide certain characteristics, such
as
reduced friction or wear characteristics as compared to the material of the
guide
bracket 82.
[0026] Figure 5 is a top, partial sectional view of a portion of the
railway car truck 10 illustrating brake beam wear liners 90 received in
corresponding
guide brackets 82 of the side frames 12, 14. Figure 5 also illustrates a
portion of the
bolster 16, the railway wheels 24 and a portion of the brake system 60. The
brake
system 60 includes brake beam assemblies 100 each including a brake beam 102,
a
strut 104, and brake heads 62 coupled to ends of the brake beam 102 and strut
104.
[0027] The brake beam 102 is generally elongated between a right
hand end 106 and a left hand end 108. The brake beam 102 extends laterally
between
the side frames 12, 14. The brake shoes 64 are coupled to the brake heads 62,
which
are provided proximate to the ends 106, 108 of the brake beam 102, generally
aligned
with the railway wheels 24.
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[0028] The strut 104 includes a right hand end 110 and a left hand
end 112. In an exemplary embodiment, the strut 104 is separate and discrete
from the
brake beam 102 and is coupled to the brake beam 102 with the ends 110, 112
proximate to the ends 106, 108, respectively. Alternatively, the strut 104 may
be
integral with the brake beam 102, such as formed as part of a common casting
process. The strut 104 extends at acute angles from the brake beam 102 to an
apex at
a center portion. A standoff section 114 extends from a center portion of the
brake
beam 102 to the apex of the strut 104.
[0029] The brake beam 102, strut 104 and standoff section 114 are
typically comprised of structural steel, and may be in the form of a hollow
structural
steel sections. One or more levers 116 are connected to the brake beam
assembly
100, such as to the standoff sections 114, to actuate the brake beam assembly
100
during braking.
[0030] The brake beam wear liners 90 are shown loaded into the
guide brackets 82. Ends of the brake beam assembly 100 are configured to
extend
into the brake beam wear liners 90. For example, the paddles 120 and paddle
caps
122 (shown in greater detail in Figure 6) may be provided at the opposite ends
of the
brake beam assembly 100 to extend into the brake beam wear liners 90. The
paddles
120 are extensions at the end of the brake beam assembly 100. The paddles 120
may
be integrally formed with the brake beam 102, the strut 104 and/or the brake
heads 62.
In other alternative embodiments, the paddles 120 may be separate and discrete
from
the other components of the brake beam assembly 100. For example, the paddles
120
may be coupled, such as fastened, to the brake beam 102, the strut 104 and/or
the
corresponding brake head 62. The paddle caps 122 are coupled to the paddles
120 to
reduce friction and wear between the brake beam assembly 100 and the brackets
82
during use of the brake system 60.
[0031] Figure 6 illustrates a portion of the brake beam assembly 100
showing one end thereof illustrating one of the paddle caps 122 poised for
loading
onto the corresponding paddle 120. The paddle 120 includes a distal end 124.
The
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paddle 120 includes a top 126 and a bottom 128. The paddle 120 includes first
and
second edges 130, 132, which may define a front and a rear of the paddle 120.
[0032] The paddle cap 122 is sized and shaped to cover at least the
end of the paddle 120. The paddle cap 122 provides a sacrificial layer over
the paddle
120. The paddle cap 122 includes a cavity 134 that receives the paddle 120.
The
cavity 134 is defined by an interior surface 136 that engages the exterior of
the paddle
120 when coupled thereto. Optionally, the paddle cap 122 may be held on the
paddle
120 by an interference fit. Alternatively, the paddle cap 122 may be secured
by other
means or processes, including bonding, welding, using fasteners, using
latches, or
other means.
[0033] The paddle cap 122 includes a top 138, a bottom 140, a distal
end 142 and first and second edges 144, 146. The first and second edges 144,
146
may define a front and a rear of the paddle cap 122. In an exemplary
embodiment,
the paddle cap 122 may have rounded edges and corners at the intersections of
the top
138, bottom 140, distal end 142 and first and second edges 144, 146. The
rounded
edges may reduce damage to the brake beam wear liner 90 when moving therein.
The
rounded edges may reduce the chance of lockup with the brake beam wear liner
90
when moving therein.
[0034] The paddle cap 122 may be manufactured from a material
having a low coefficient of friction. The paddle cap 122 may be manufactured
from a
material having a lower coefficient of friction than the paddle 120. The
paddle cap
122 may be manufactured from a material that is less abrasive than the paddle
120.
The paddle cap 122 may be manufactured from a material having a coefficient of
friction that is less than half the coefficient of friction of the paddle 120.
Optionally,
the paddle cap 122 may be manufactured from the same or a similar material as
the
brake beam wear liner 90 (shown in Figure 5). In an exemplary embodiment, the
paddle cap 122 may be manufactured from a polymer material, such as a
synthetic
material, a nylon material, a high molecular weight polyethylene material, and
the
like. The paddle cap 122 may be molded or may be manufactured by other
processes.
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[0035] Returning to Figure 5, during operation of the brake system
60, the brake beam assemblies 100 may be pressed toward the corresponding
railway
wheels 24 to apply braking pressure to the railway wheels 24. The levers 116
actuate
the brake assemblies 100 during braking. Movements of the brake beam
assemblies
100 are guided by the brake beam wear liners 90. For example, the brake beam
wear
liners 90 limit movement of the brake beams 102 along a generally linear path
toward,
and away from, the railway wheels 24. The brake beams 102 have a linear range
of
motion defined by the brake beam wear liners 90.
[0036] The brake beam assemblies 100 are not physically connected
to the side frames 12, 14. Rather, the brake beam assemblies 100 are free-
floating
between the side frames 12, 14. The brake beam assemblies 100 have an axial
length
measured between the distal ends 142 of the paddle caps 122. The axial length
of
each brake beam assembly 100 is selected to fit between the brake beam wear
liners
90. The brake beam wear liners 90 associated with a particular brake beam
assembly
100 are spaced apart from one another by a lateral distance that is longer
than the
axial length of the brake beam assembly 100. As such and with the low
coefficient of
friction and round edges of paddle caps 122, binding of the brake beam
assembly 100
is reduced or eliminated.
[0037] During operation of the brake system 60, the brake beam
assemblies 100 are actuated between retracted positions and advanced
positions. In
the retracted position, the brake beams 102 are positioned closer to the
bolster 16. In
the advanced position, the brake beams 102 are actuated away from the bolster
16,
thus pushing the brake shoes 64 toward the corresponding railway wheels 24 to
apply
braking pressure to the railway wheels 24. The levers 116 actuate the brake
assemblies 100 during braking. Movement of the brake beam assemblies 100 is
guided by the brake beam wear liners 90. For example, the brake beam wear
liners 90
limit movement of the paddles 120 and paddle caps 122, and thus the brake
beams
102, along a generally linear path toward, and away from, the railway wheels
24
between the advanced and retracted positions. The brake beams 102 have a
linear
range of motion defined by the brake beam wear liners 90.
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[0038] During operation of the brake system 60, the paddle caps 122
reduce the friction between the brake beam assembly 100 and the brackets 82.
More
braking force can be applied to the wheels 24 as opposed to using a portion of
such
force to overcome the forces to move the brake beam assembly 100 from the
retracted
position to the advanced position. As compared to conventional systems without
paddle caps, the paddle caps 122 protect the paddles 120 and reduce wear on
the
paddles 120 and on the brake beam wear liners 90. For example, conventional
brake
systems put the paddle in direct contact with the brake beam wear liner 90 and
the
hardened, rough surface of the paddle increases wear on the brake beam wear
liner 90.
The steel-polymer (or steel-steel) sliding surface between conventional brake
systems
and the brake beam wear liner 90 has a high coefficient of friction and thus
increased
resistance to braking action, which can create more stress and wear on the
brake beam
wear liner 90. Increased resistance may reduce the braking efficiency and may
reduce
the service life of the brake pads due to heavy drag.
[0039] The brake system 60, with the paddles caps 122, provides a
polymer-polymer (or polymer-steel) sliding surface between the brake beam
assembly
100 and the brake beam wear liner 90, which reduces friction and wear. Reduced
wear over time on the components of the railway car truck 10 increases the
service
life of the railway car truck 10. The reduction in friction reduces drag when
the
brakes are released, which may increase the service life of the brake pads 64.
Additionally, providing the paddle caps 122 may reduce a cost of manufacture
of the
brake beam assembly 100 by eliminating the need to flame harden the paddles
120, as
is typical of conventional brake beam assemblies to prevent wear of the
paddles of
such assemblies. Flame hardening is a process that adds expense to the
manufacture
of the paddles 120, and eliminating the need for such process may reduce the
overall
cost of manufacturing the paddles 120 and/or the brake beam 102.
[0040] The paddle caps 122 may take up portions of gaps that would
otherwise exist between the paddles 120 and the brake beam wear liners 90. For
example, portions of gaps between the paddles 120 and the bases 98 of the
brake
beam wear liners 90. By partially filling such gaps, the paddle caps 122 may
help
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center or align the brake beam assembly 100 between the. side frames 12, 14
and
prevent binding of either end of the paddles 120 with the brake beam wear
liners 90.
For example, the brake beam assembly 100 may move freely and squarely between
advanced positions and retracted positions as the brake beam assembly 100 is
actuated
and released, and apply bralcing force evenly on both brake shoes 64. Holding
the
brake beam assembly 100 in position may further prevent the railway wheels 24
from
tilting causing premature wear of the wheels 24 and rail tracks. The radiused
or
curved ends of the paddle caps 122 may reduce friction and/or damage between
the
paddle caps 122 and the brake beam wear liners 90. Having the distal ends 142
of the
paddle caps 122 parallel to the base 98 may reduce friction and/or damage
between
the paddle caps 122 and the brake beam wear liners 90, for example by ensuring
a
surface as opposed to an edge engages the brake beam wear liners 90.
[0041] It is to be understood that the above description is intended to
be illustrative, and not restrictive. For example, the above-described
embodiments
(and/or aspects thereof) may be used in combination with each other. In
addition,
many modifications may be made to adapt a particular situation or material to
the
teachings of the invention without departing from its scope. Dimensions, types
of
materials, orientations of the various components, and the number and
positions of the
various components described herein are intended to define parameters of
certain
embodiments, and are by no means limiting and are merely exemplary
embodiments.
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Many other embodiments and modifications within the scope of the claims will
be apparent to those of skill in the art upon reviewing the above description.
The
scope of the invention should, therefore, be determined with reference to the
appended claims, along with the full scope of equivalents to which such claims
are entitled. In the appended claims, the terms "including" and "in which" are
used as the plain-English equivalents of the respective terms "comprising" and
"wherein." Moreover, in the following claims, the terms "first," "second," and
"third," etc. are used merely as labels, and are not intended to impose
numerical
requirements on their objects.
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