Note: Descriptions are shown in the official language in which they were submitted.
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TRUCK BOLSTER
Field of the Invention
This invention relates to the field of rail road cars, and to bolsters for
trucks for rail road
cars.
Background of the Invention
In railroad rolling stock it is known to employ trucks to support railroad car
bodies
during motion along railroad tracks. Commonly, a rail road car truck may have
a pair of side
frames, or side frame assemblies, that seat upon wheelsets, and a truck
bolster that extends
crosswise between, and is resiliently mounted to, the side frames. The bolster
may typically
have a centerplate bowl located at mid-span. The car body may include a
centerplate that seats
in the centerplate bowl in a relationship that permits a vertical load from
the car body to be
passed into the truck bolster while also permitting rotational pivoting of the
bolster relative to the
car body such that the truck can turn and the rail road car can negotiate
curves in the track.
As a first approximation, at the simplest level of analysis, the truck bolster
may be
considered to be a simply supported beam. The car body and lading may be
idealized as a
vertically downward point load applied at the mid-span center of the beam.
This point load is
reacted by a pair of reactions, which may for initial approximation also be
idealized as point
loads, that act vertically upwardly at the beam ends, those reactions being
provided by the main
spring groups. The main spring groups have upper seats on the undersides of
the ends of the
bolster, and lower seats on the tension member of the side frames. Truck
bolsters may tend to
have the general form of a beam having a top flange, a bottom flange, and
shear webs extending
between the top and bottom flanges. The bending moment in the truck bolster
may tend to be
greatest at mid span. Consequently, the beam may tend to be deepest in section
at the mid span
location. While welded or riveted truck bolsters are known, truck bolsters
tend commonly to be
castings, most typically steel castings.
Truck bolsters may have side bearings mounted on their upper flanges some
distance
outboard from the centerplate. The side bearings receive vertical loads that
are transmitted,
typically, between a body bolster of the railroad car body, and the truck
bolster. This may tend to
occur most particularly when the car body is in a condition where it may lean
to one side relative
to the truck bolster. The side bearing may include a roller or a slider that
permits this transfer of
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force to occur while also permitting a turning, or pivoting motion of the
truck bolster relative to
the body bolster. When the railroad car body is in a rocking or leaning
condition, the vertical
force transmitted into the side bearing, and hence into the bolster arm
beneath the side bearing,
can be quite substantial.
Summary of the Invention
In a first aspect of the invention there is a truck bolster for a railroad
freight car truck.
The truck bolster is a casting. The truck bolster includes a beam having an
upper flange portion,
a lower flange portion, a first web portion and a second web portion, the
upper and lower flange
portions and the first and second web portions being outside walls of the beam
defining a hollow
box section. The beam has first and second ends for mounting to rail road car
truck sideframes.
A centerplate bowl is located at mid-span between the first and second ends.
There is a shear
transfer reinforcement mounted within the beam. A first portion of the shear
transfer
reinforcement is mounted to receive downward forces from the centerplate. A
second portion of
the shear transfer reinforcement has a shear force transfer connection to the
first web, and a third
portion of the shear transfer reinforcement has a shear transfer connection to
the second web.
In another feature of that aspect of the invention, the shear transfer
reinforcement is a
web mounted cross-wise within the beam. In another feature, the web is mounted
diametrically
under the center plate bowl. In a further feature, the web has an
accommodation formed therein
for receiving a centerplate pin. In another feature, the truck bolster has a
reinforcement running
lengthwise under the centerplate bowl, the truck bolster has a reinforcement
running lengthwise
under the centerplate bowl, and the lengthwise running reinforcement
intersects the cross-wise
web. In a further feature, the reinforcement running lengthwise is a rib
protruding downwardly
from the centerplate bowl and furthermore the rib flares laterally.
In another feature, the shear transfer reinforcement is an archway and in
another feature,
the archway has an apex near to the centerplate bowl, and the second and third
portions of the
reinforcement are legs of the archway extending away therefrom. In an
additional feature, the
archway inclines at an angle from vertical. In a different feature, the truck
bolster is free of
longitudinally running, upwardly standing webs underneath the archway.
In a further feature, the internal shear transfer reinforcement is a first
internal shear
transfer reinforcement. The first internal shear transfer reinforcement is a
cross-wise web
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standing in a vertical plane at a mid span plane of symmetry of the
centerplate bowl and the
truck bolster includes a second internal shear transfer reinforcement. The
second internal shear
transfer reinforcement is a cross-wise archway spaced outboard from the first
internal shear
transfer reinforcement and the cross-wise archway has a first leg rooted in
the first web portion, a
second leg rooted in the second leg portion, and an upper portion running
under the upper flange
portion between the leg portions. In another feature, a depending centerplate
reinforcement rib
runs length-wise from the upper portion of the archway to an upper region of
the cross-wise web.
In another feature, the truck bolster has first and second brake rod apertures
formed in the
first and second web portions respectively, and the first and second brake rod
apertures each
have an area of more than 40 sq. in. In a further feature, the first brake rod
aperture has an area,
A, that is at least 50 % greater than the largest corresponding brake rod
opening defined in AAR
standard S-392, as that standard read on January 1, 2005, and identified as
"conventional brake
rod opening". In an additional feature, the first brake rod aperture has a
perimeter, P, that
encompasses the location of both (a) a "conventional brake rod opening"; and
(b) a
WABCOPACTM brake rod opening, as those brake rod openings were defined in AAR
Standard S ¨ 392, as that standard read on January 1, 2005. In another
feature, the area A of the
brake rod opening exceeds by more than 80 % the area of the largest brake rod
opening defined
in AAR standard S ¨ 392 as that standard read on January 1, 2005. In a further
feature, the brake
rod aperture of the truck bolster has a perimeter, and the perimeter is free
of any radius of
curvature of less than 2 Y2 inches. In an extra feature, the brake rod opening
has a plurality of
radiused corners, at least one of the corners having a different radius than
another. In an
additional feature, the brake rod opening has a radiused corner having a
radius of more than 5
inches.
In another feature, the brake rod opening has a radiused corner having a
radius more than
50 % greater than any radius shown for a brake rod opening in AAR standard S-
392, as that
standard read on January 1, 2005. In an additional feature, the brake rod
opening of the truck
bolster has a perimeter; AAR standard S ¨ 392 as it read on January 1, 2005
defines a
corresponding "conventional brake rod opening", AAR standard S ¨ 392 as it
read on January 1,
2005 defines a corresponding "WABCOPAC" brake rod opening, and the perimeter
of the brake
rod opening of the truck bolster encompasses both the "conventional brake rod
opening" and the
"WABCOPAC" brake rod opening. In a further feature, the brake rod opening of
the truck
bolster has a perimeter, P, and a first characteristic dimension Dh, Dh being
calculated according
to the formula Dh = 4A/P, and Dh is greater than 6 Y2 inches. In another
feature, Dh is greater
than 8 inches.
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In another feature, the first brake rod aperture of the truck bolster has a
perimeter, P, an
area A, and a first characteristic dimension Dh, Dh being calculated according
to the formula Dh
= 4A/P. The first brake rod aperture has a second characteristic dimension,
Dp, Dp being
calculated according to the formula Dp = (Mr) and a ratio of Dh/Dp lies in the
range of 0.9 to
1Ø In a further feature, the truck bolster has a ratio of Dh/Dp greater than
0.94.
In a different feature, the first brake rod aperture of the truck bolster has
a perimeter, P,
an area A, and a first characteristic dimension Dh, Dh being calculated
according to the formula
Dh = 4A/P. The first brake rod aperture has a second characteristic dimension,
Dc, Dc being
calculated according to the formula Dc = the square root of [4Ahr], and a
ratio of Dh/Dc lies in
the range of 0.95 to 1Ø In a further feature, the upper flange portion has
an upper surface, the
truck bolster has side bearing seats defined on the upper surface, and the
truck bolster has side
bearing fitting access sockets formed therein abreast of the side bearing
seats. In another feature,
the upper flange portion has an upper surface, the truck bolster has side
bearing seats defined on
the upper surface, and the web portions of the truck bolster have deviations
therein abreast of the
side bearing seats, the deviations defining side bearing fitting access
sockets.
In a further feature, the truck bolster has brake rod apertures in the first
and second web
portions, the brake rod apertures being located generally beneath the
centerplate bowl and the
first and second web portions are free of tool access openings outboard of the
brake rod
apertures.
In another aspect of the invention, there is a truck bolster of a railroad
freight car truck,
the truck bolster being a casting. The truck bolster has a hollow beam having
first and second
ends for mounting to sideframes. The truck bolster has a lengthwise direction
running between
the first and second ends. The hollow beam has an upper flange portion, a
lower flange portion,
a first web portion and a second web portion, the upper and lower flange
portions and the first
and second web portions being outside walls of the beam that co-operate to
define a box section.
There is a centerplate bowl located at mid-span between the first and second
ends and an internal
shear web mounted cross-wise relative to the lengthwise direction. The
internal shear web is
mounted to reinforce the centerplate bowl. The cross-wise web extends from the
center plate
bowl to the lower flange portion, and from the first web to the second web.
In another feature, the internal shear web extends diametrically beneath the
centerplate
bowl. In a different feature, the internal shear web has an accommodation
formed therein to
accommodate a centerplate pin. In another feature, the internal shear web has
feet merging into
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the lower flange portion, and a relief defined adjacent to the lower flange
portion between the
feet. In another feature, the bolster has a longitudinally running centerplate
reinforcement rib,
and the rib intersects the internal shear web.
In a further aspect of the invention, there is a truck bolster for a railroad
freight car truck.
The truck bolster includes a beam having a first end for mounting to a first
sideframe, a second
end for mounting to a second sidefi-ame, and a centerplate bowl at mid-span
between the first and
second ends. The truck bolster has side bearing seats defined thereon, and
attachment fittings for
the side bearing seats. The truck bolster has side bearing fitting access
sockets formed in the
beam abreast of the side bearing seats.
In another feature of that aspect of the invention, the beam has an upper
flange and webs
extending lengthwise therealong and downwardly therefrom. The sidebearing
seats are defined
on the upper flange, and the sockets are formed in the webs. In an additional
feature, a wall of
one of the sockets is formed by a deviation formed in one of the webs. In
another feature, the
beam includes a top flange and a pair of spaced apart webs running along, and
extending
downwardly therefrom, the attachment fittings include two spaced apart bores
formed through
the top flange, the bores having centerlines, and at least a portion of one of
the webs passes
between the centerlines of the bores.
In another aspect of the invention, there is a railroad freight car truck
bolster. The truck
bolster is a casting. The truck bolster includes a hollow beam having a first
and a second end for
mounting in a rail road car truck sidefiume, and a centerplate bowl mounted in
a mid-span
position between the first and second ends. Brake rod apertures are formed in
the beam, the
brake rod apertures being located generally beneath the centerplate bowl. The
hollow beam has
an upper flange, a lower flange, and predominantly upwardly standing first and
second webs
extending between the upper and lower flanges. The first and second webs being
free of hand
access openings outboard of the brake rod apertures. In a feature of that
aspect of the invention,
side bearing seats are defined on the upper flange of the truck bolster, side
bearing fitting access
sockets are defined in the webs abreast of the side bearing seats, and the
webs are substantially
planar between the brake rod apertures and the sockets.
In yet another aspect of the invention there is a truck bolster for a railroad
freight car
truck, the truck bolster having a brake rod opening defined therein. The brake
rod opening has
an area, A, of greater than 40 sq. in. In another feature of that aspect of
the invention, the brake
rod opening area is greater than 50 sq. in. In another feature, the area A
exceeds by at least 80 %
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the area of the largest corresponding brake rod opening defined in AAR
standard S ¨ 392 as that
standard read on January 1, 2005.
In a further feature, the brake rod opening of the truck bolster has a
perimeter, and the
perimeter is free of any radius of curvature of less than 21/2 inches. In
another feature, the brake
rod opening has a plurality of radiused corners, at least one of the corners
having a different
radius than another. In a further feature, the brake rod opening has a
radiused corner having a
radius of more than 5 inches. In another feature, the brake rod opening has a
radiused corner
having a radius more than 50 % greater than any radius shown for a brake rod
opening in AAR
standard S-392 as it read on January 1, 2005. In a further feature, the brake
rod opening of the
truck bolster has a perimeter, AAR standard S ¨ 392, as it read on January 1,
2005 defines a
corresponding "conventional brake rod opening", AAR standard S ¨ 392, as it
read on January 1,
2005 defines a corresponding WABCOPACTM brake rod opening, and the perimeter
of the
brake rod opening of the truck bolster encompasses both the "conventional
brake rod opening"
and the WABCOPACTM brake rod opening.
In another feature, the brake rod opening of the truck bolster has a
perimeter, P, and a
first characteristic dimension Dh, Dh is calculated according to the formula
Dh = 4A/P, and Dh
is greater than 6 'A inches. In a further feature, Dh is greater than 7 1/2
inches. In an additional
feature, the brake rod opening of the truck bolster has a perimeter, P, and a
first characteristic
dimension Dh, Dh being calculated according to the formula Dh = 4A/P. The
brake rod opening
has a second characteristic dimension, Dp, Dp being calculated according to
the formula Dp =
(Phi) and a ratio of Dh/Dp lies in the range of 0.9 to 1Ø In a further
feature the ratio Dh/Dp is
greater than 0.94. In another feature, the brake rod opening of the truck
bolster has a perimeter,
P, and a first characteristic dimension Dh, Dh being calculated according to
the formula Dh =
4A/P. The brake rod opening has a second characteristic dimension, Dc, Dc
being calculated
according to the formula Dc = the square root of [4A/rr] and a ratio of Dh/Dc
lies in the range of
0.95 to 1Ø
In another aspect of the invention there is a truck bolster. The bolster is a
casting and has
a rating of at least "100 Tons". The bolster has a top flange, a bottom
flange, and webs
extending between the top and bottom flanges. The flanges and the webs co-
operate to define a
hollow beam. The beam has a deep central portion and shallower end portions.
The bottom
flange includes first and second portions ascending outboard from the deep
central portion to the
end portions. The first ascending portion lies in a plane. The first ascending
portion merges into
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a first of the end portions at a first transition. The first transition is
free of any deviation
extending inboard and upward of the plane.
In a further aspect of the invention, there is a truck bolster. The bolster is
a casting and
has a rating of at least "100 Tons". The bolster has a top flange, a bottom
flange, and webs
extending between the top and bottom flanges. The flanges and the webs co-
operate to define a
hollow beam. The beam has a deep central portion and shallower end portions.
The bottom
flange includes first and second portions ascending outboard from the deep
central portion to the
end portions. The bottom flange has a first transition from the deep central
portion to the
ascending portion and a second transition from the ascending portion to the
end portion,
respectively. The first transition has a first radius of curvature, R1. The
second transition has a
second radius of curvature, R2 and R2 is at least one half of RI.
These and other aspects and features of the invention may be understood with
reference
to the description which follows, and with the aid of the illustrations of a
number of examples.
Brief Description of the Figures
The description is accompanied by a set of illustrative Figures in which:
Figure la is an isometric, general arrangement view of a railroad car truck
such as may
incorporate a truck bolster;
Figure lb is a perspective view of the truck bolster of Figure la, from above
and to one
side;
Figure lc is a further perspective view of the truck bolster of Figure la,
from below and
to one side;
Figure 2a is a top view of the truck bolster of Figure la;
Figure 2b shows a side, or elevation, view of the bolster of the truck of
Figure la, one
half of that view being a sectional view taken along the longitudinal
centerline of the
truck bolster as indicated by section `2b ¨ 2b' in Figure 2a;
Figure 2c is a half cross-sectional view, in elevation, on '2c ¨ 2c' of the
bolster of Figure
2b;
Figure 2d is an enlarged detail of a lightening aperture of the truck bolster
of Figure 2a;
Figure 2e is an enlarged cross-sectional detail taken on the longitudinal
centerline of the
truck bolster of Figure 2d, from the same viewpoint as that of Figure 2d;
Figure 2f is an enlarged detail, from above, of a side bearing seat region of
the bolster of
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Figure 2a.
Figure 3a is an end, or profile, view of the truck bolster of Figure 2a;
Figure 3b is a cross-sectional view, in profile, on `3b - 3b' of the bolster
of Figure 2b
taken through the center row of the spring seat;
Figure 3c is a cross-sectional view, in profile, on '3c ¨ 3c' of Figure 2b
taken through the
center of the spring row inboard row of the spring seat;
Figure 3d is a cross-sectional view, in profile, on '3d ¨ 3d' of Figure 2b
taken through
the side bearing mount;
Figure 3e is a cross-sectional view, in profile, on '3e ¨ 3e' of Figure 2b
taken on a
staggered section predominantly to one side of the midspan vertical plane of
the truck
bolster;
Figure 3f is a cross-sectional view, in profile, on '3f¨ 3f of Figure 2b taken
in the mid-
span vertical plane of the truck;
Figure 4a shows a prior art truck bolster in profile; and
Figure 4b shows the truck bolster of Figure 2a in a profile contrasting with
that of Figure
4a.
Detailed Description
The description that follows, and the embodiments described therein, are
provided by
way of illustration of an example, or examples, of particular embodiments of
the principles and
aspects of the present invention. These examples are provided for the purposes
of explanation,
and not of limitation, of those principles and of the invention. In the
description, like parts are
marked throughout the specification and the drawings with the same respective
reference
numerals. The drawings are not necessarily to scale and in some instances
proportions may have
been exaggerated in order more clearly to depict certain features of the
invention.
In terms of general orientation and directional nomenclature, for the rail
road car truck
described herein, the longitudinal direction is defined as being coincident
with the rolling
direction of the rail road car, or rail road car unit, when located on tangent
(that is, straight)
track. In the case of a rail road car having a center sill, the longitudinal
direction is parallel to
the center sill, and parallel to the side sills, if any. Unless otherwise
noted, vertical, or upward
and downward, are terms that use top of rail, TOR, as a datum. In the context
of the truck as a
whole, the term lateral, or laterally outboard, refers to a distance or
orientation relative to the
longitudinal centerline of the railroad car, or car unit, or of the centerline
of the centerplate bowl
of the truck. The term "longitudinally inboard", or "longitudinally outboard"
is a distance taken
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relative to a mid-span lateral section of the truck. Pitching motion is
angular motion of a railcar
unit about a horizontal axis perpendicular to the longitudinal direction.
Yawing is angular
motion about a vertical axis. Roll is angular motion about the longitudinal
axis.
In the context of the truck bolster, such as bolster 24, described below, when
the car is
stationary on straight, level track, the long, or longitudinal axis 25 of the
truck bolster tends to be
oriented cross-wise to the longitudinal axis of the truck or of the railroad
car more generally. In
this description, the lengthwise axis of the bolster may be considered the x-
axis. The transverse
direction of the bolster may be considered the direction of the fore-and-aft
thickness of the
bolster, relative to the rolling direction of the truck, and may be designated
the y-axis. The up
and down direction, which may be parallel to the axis of the centerplate pin,
when installed, may
be considered the vertical or z-direction.
Reference may be made herein to various plate sizes or standards of the
Association of
American Railroads, the AAR. Unless otherwise specified, those standards are
to be interpreted
as they were at the date of filing of this application, or if priority is
claimed, then as of the
earliest date of priority of any application in which the standard is
identified, those standards
being understood to read the same as they did on January 1, 2005.
This description relates to rail car trucks and truck components. Several AAR
standard
truck sizes are listed at page 711 in the 1997 Car & Locomotive Cyclopedia. As
indicated, for a
single unit rail car having two trucks, a "40 Ton" truck rating corresponds to
a maximum gross
car weight on rail (GRL) of 142,000 lbs. Similarly, "50 Ton" corresponds to
177,000 lbs., "70
Ton" corresponds to 220,000 lbs., "100 Ton" corresponds to 263,000 lbs., and
"125 Ton"
corresponds to 315,000 lbs. In each case the load limit per truck is then half
the maximum gross
car weight on rail. Two other types of truck are the "110 Ton" truck for
railcars having a
286,000 lbs. GRL and the "70 Ton Special" low profile truck sometimes used for
auto rack cars.
Given that the rail road car truck described herein may tend to have both
longitudinal and
transverse axes of symmetry, a description of one half of an assembly may
generally also be
intended to describe the other half as well, allowing for differences between
right hand and left
hand parts.
This description refers, in part, to friction dampers, and damper seats for
rail road car
trucks, and to multiple friction damper systems. There are several types of
damper
arrangements, some being shown at pp. 715 -716 of the 1997 Car and Locomotive
Cyclopedia.
Each of the arrangements of dampers shown
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at pp. 715 to 716 of the 1997 Car and Locomotive Cyclopedia can be modified to
employ a four
cornered, double damper arrangement of inner and outer dampers. In terms of
general
nomenclature, damper wedges tend to be mounted within an angled "bolster
pocket" formed in
an end of the truck bolster. In cross-section, each wedge may then have a
generally triangular
shape, one side of the triangle being, or having, a bearing face, a second
side which might be
termed the bottom, or base, forming a spring seat, and the third side being a
sloped side or
hypotenuse between the other two sides. The first side may tend to have a
substantially planar
bearing face for vertical sliding engagement against an opposed bearing face
of one of the
sideframe columns. The second face may not be a face, as such, but rather may
have the form of
a socket for receiving the upper end of one of the springs of a spring group.
Although the third
face, or hypotenuse, may appear to be generally planar, in some embodiments it
may tend to
have a slight crown, having a radius of curvature of perhaps 60". The crown
may extend along
the slope and may also extend across the slope. The end faces of the wedges
may be generally
flat, and may have a coating, surface treatment, shim, or low friction pad to
give a smooth sliding
engagement with the sides of the bolster pocket, or with the adjacent side of
another
independently slidable damper wedge, as may be.
During railcar operation, the sideframe may tend to rotate, or pivot, through
a small range
of angular deflection about the end of the truck bolster to yield wheel load
equalisation. The
slight crown on the slope face of the damper may tend to accommodate this
pivoting motion by
allowing the damper to rock somewhat relative to the generally inclined face
of the bolster
pocket while the planar bearing face remains in planar contact with the wear
plate of the
sideframe column. Although, in some embodiments the slope face may have a
slight crown, for
the purposes of this description it will be described as the slope face or as
the hypotenuse, and
will be considered to be a substantially flat face as a general approximation.
In the terminology herein, wedges may have a primary angle a, being the
included angle
between (a) the sloped damper pocket face mounted to the truck bolster, and
(b) the side frame
column face, as seen looking from the end of the bolster toward the truck
center. In some
embodiments, a secondary angle p may be defined in the plane of angle a,
namely a plane
perpendicular to the vertical longitudinal plane of the (undeflected) side
frame, tilted from the
vertical at the primary angle. That is, this plane is parallel to the
(undeflected) long axis of the
truck bolster, and taken as if sighting along the back side (hypotenuse) of
the damper. The
secondary angle p is defined as the lateral rake angle seen when looking at
the damper parallel to
the plane of angle a. As the suspension works in response to track
perturbations, the wedge
forces acting on the secondary angle 1 may tend to urge the damper either
inboard or outboard
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according to the angle chosen.
Figure la shows an example of a rail road car truck 20 that is intended to be
generically
representative of a wide range of trucks in which the present invention may be
employed. While
truck 20 may be suitable for general purpose use, it may be optimized for
carrying relatively low
density, high value lading, such as automobiles or consumer products, for
example, or for
carrying denser semi-finished industrial goods, such as might be carried in
rail road freight cars
for transporting rolls of paper, or for carrying dense commodity materials be
they coal, metallic
ores, gain, potash, steel coils or other lading. Truck 20 is generally
symmetrical about both its
longitudinal and transverse, or lateral, centreline axes. Where reference is
made to a sideframe,
it will be understood that the truck has first and second sideframes, first
and second spring
groups, and so on.
Truck 20 has a truck bolster 24 and first and second side frames 26. Side
frames 26 may
be metal castings, and may preferably be steel castings. Each side frame 26
has a generally
rectangular side frame window 28 that accommodates one of the ends 30 of the
bolster 24. The
upper boundary of window 28 is defined by the side frame arch, or compression
member
identified as top chord member 32, and the bottom of window 28 is defined by a
tension member
identified as bottom chord 34. The fore and aft vertical sides of window 28
are defined by a pair
of first and second side frame columns 36. The ends of the tension member
sweep up to meet
the compression member. At each of the swept-up ends of side frame 26 there
are side frame
pedestal fittings, or pedestal seats 38. Each fitting 38 accommodates an upper
fitting, which may
be a rocker or a seat. This upper fitting, whichever it may be, is indicated
generically as 40.
Fitting 40 engages a mating fitting 42 of the upper surface of a bearing
adapter 44. Bearing
adapter 44 engages a bearing 46 mounted on one of the ends of one of the axles
48 of the truck
adjacent one of the wheels 50 of one of the wheelsets. A fitting 40 is located
in each of the fore
and aft pedestal fittings 38, the fittings 40 being longitudinally aligned.
In operation, bolster 24 is able to pivot about the vertical or z-axis with
respect to the
body of the railroad car, or car unit, more generally, while the vertical load
of the railroad car is
carried into the bolster through the center plate bowl 74 and the side
bearings 35. Bolster 24 can
move up and down in the side frame windows 28 on the spring groups 45 in
response to vertical
perturbations. The vertical motion may tend to carry along friction dampers
47, 49 seated in the
bolster pockets 120, 122 of bolster 24, causing friction dampers 47, 49 to
ride against the side
frame columns 36, and thereby to damp out the motion. Dampers 47,49 may be
arranged in first
and second damper groups, mounted respectively at the first and second ends of
bolster 24. Each
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damper group may include 4 dampers. Each of those dampers may be sprung
independently of
any other, and may be arranged in a four cornered arrangement, namely with two
dampers facing
each sideframe, one being outboard of the other. Bolster 24 may be displaced
laterally relative
to the side frames in response to lateral perturbations, subject to the range
of travel permitted by
the bolster gibs 112, 114. The spring groups 45 and the sideways swinging, or
rocking motion of
the side frames may tend to resist this lateral motion and may tend to restore
bolster 24 to an
equilibrium position with the amplitude of the lateral rocking or swinging
motion decreasing as
the dampers work against the side frame column wear plates. When side-to-side
leaning or
rocking motion of the car body occurs, loads may be carried into the truck
bolster at the side
bearings 35 mounted to the upper surface of bolster 24 from the engaging side
bearing surfaces
of the body bolster of the rail road car body.
Bolster 24 may be thought of as having three types of regions: (1) the deepest
portion
lying generally underneath the center plate bowl; (2) relatively shallow end
portions or regions
that locate in the sidefi-ame windows; and (3) intermediate transition
regions, or arms, that
extends between the first and second regions. These regions are identified as
center or mid-span
region 62, intermediate or transition arm region 64, and outboard, or end
region 66.
Bolster 24 may have a long axis, 25. Bolster 24 may have a plane of symmetry
that runs
lengthwise (i.e., along axis 25) and vertically. Aside from such features as
brake fittings, bolster
24 may also have a mid-span vertical plane of symmetry that is perpendicular
to long axis 25.
Mid-span centerline 27 lies in this vertical plane to which axis 25 is normal.
Bolster 24 may
include an upper portion, 52, a lower portion 54, a first sidewall portion 56
and a second sidewall
portion 58. These portions may be joined in a generally box-like
configuration, in section, to
form a beam in which upper portion 52 may tend to function as a first flange,
lower portion 54
may tend to function as a second flange, and first and second sidewall
portions 56 and 58 may
tend to be, or to function as, shear transfer members, or shear transfer webs,
linking the upper
and lower portions 52 and 54. That is to say, the portions 52, 54, 56, and 58
co-operate to define
a beam having webs and flanges, which beam may have a hollow interior,
indicated generally as
60, which may include one or more cavities or sub-cavities. This beam may tend
to have a
greater through thickness depth between the upper and lower flanges in its mid-
span region 62
than at its shallower end regions 66. These portions may be integrally formed
portions of a
single monolithic casting, 70, which may be fabricated of a material such as a
steel alloy. In
operation, the upper flange may tend to be a compression member, and the lower
flange may
tend to be a tension member.
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Upper portion 52 may include a wall member, which may be identified as an
upper
flange 72. At the mid span location, upper flange 72 may have an upstanding
generally circular
lip or rim 73, having a diameter 073, that defines the outer peripheral wall
of a center plate bowl
74, such as may accommodate a mating center plate of a railroad car body. At
the center of the
center plate bowl, there may be a concentrically located accommodation for a
center plate pin,
that accommodation being indicated generally as 76. At some distance radially
away from
accommodation 76, laterally outboard beyond the rim of bowl 74, there may be a
side bearing
mount, or seat, 78. Seat 78 may be a raised portion of upper flange 72. That
is, it may stand
proud of the surrounding region, and, where bolster 24 is a casting, after
casting, seat 78 may be
milled to give a machined flat, or other configuration to yield an interface
80 to which a side
bearing, such as side bearing 35 may be mounted. Flange 72 may include
mounting fittings 82,
84 such as may permit mechanical attachment of side bearing 35 to seat 78. For
example,
fittings 82, 84 may include bores 86, 88, and the mechanical attachment may be
by way of bolts
or other threaded fasteners. In one embodiment, the side bearing seat may be a
generally
rectangular flat patch, centered roughly 25 inches outboard of the mid span
truck centerline.
Flange 72 may have a downwardly sloped transition 90 lying outboard of seat
78, and a more
distant distal region 92 such as may pass through the sideframe window.
Lower portion 54 may include a lower flange member 96, such as may have a mid-
span
portion 100 lying generally beneath center plate bowl 74; upwardly and
outwardly inclined
sloped regions 102 lying outboard thereof; and distal regions 104 extending
from the inclined
regions 102 to the end of bolster 24. The through thickness of lower flange
member 96 may tend
to be greatest in mid-span portion 100, and may be tapered in a general
reduction in thickness in
inclined regions 102, to a once again thicker portion in distal end regions
104. The underside of
distal region 104 may include fittings in the nature of spring coil end
retainers 105 defining the
upper spring seat 107 for receiving the upper ends of the spring coils of the
spring group, and for
receiving the upper ends of the friction dampers.
Each of first and second side wall portions 56, 58 may include a deep central
region 106,
which may extend between, and form a shear web connection between, (a) the mid
span region
of upper flange 72 under center plate bowl 74 and (b) mid-span portion 100 of
lower flange
member 96. Sidewall portions 56, 58 may further include a transition or
intermediate portion
108, and an end portion 110. Transition portion 108 may narrow in depth (i.e.,
become more
shallow) from the inboard portion to the outboard portion, and again, may form
the shear web
connection between the upper and lower flanges in transition region 102.
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Sidewall portions 56, 58 may include inboard gibs 112 and outboard gibs 114.
Either or
both of those gibs may be tapered as described in my copending US Patent
Application 11 /
002,222 filed December 3, 2004. Each end of bolster 24 may further include
inboard and
outboard bolster pockets, 120, 122. Inboard bolster pocket 120 may have a
substantially planar
inclined face 124 that may be inclined with respect to the vertical by a
primary angle a. Face
124 may also include a lateral bias, represented by secondary angle p. The
apparent lateral rake
angle, 0, of the bolster pocket due to secondary angle p may be seen in the
downwardly looking
sectional view of Figure 2c, but a true view of secondary angle II may be seen
by sighting along
the inclined plane of angle a. Bolster pocket 120 may include an outboard
lateral wall 128
extending perpendicular to long axis 25. Wall 128 co-operates with the sloped
wall defined by
face 124 to form a two sided notch with a face width corresponding to the
width of a damper
wedge, with tolerance, such that a damper wedge installed in pocket 120 may
tend to be
constrained to work along face 124 and along the walled guideway or trackway
defined by wall
128, with a tendency to bear against wall 128 by virtue of the secondary rake
angle, p. Similarly,
outboard pocket 122 may include an inclined face 125 that may be inclined at
primary angle a
and secondary angle (3, but of opposite hand, and an inboard wall 130, which
may be spaced in
mirror arrangement to wall 128 and face 124. Bolster 24 may include a spring
land 134 between
walls 128 and 130. An intermediate end row coil spring of spring group 45 may
bear against the
underside of land 134. Land 134 may be part of the upper spring seat 107. In
contrast to
conventional bolster pockets that may have 3 walls (namely a sloped face
bracketed between a
pair spaced apart parallel side walls), in some embodiments the bolster pocket
or pockets, may
have only two walls namely, the sloped face and one side face. For example,
bolster pocket 120
may have only face 124 and outboard wall 128 to which axis 25 is normal. In
this embodiment
slope face 124 may merge on a radiused edge into the vertical web portion 56
rather than into
another bolster pocket sideface. This may tend to reduce the sharpness or
suddenness of the
transition in width of, for example, the bottom flange in the transition
region from the arm region
to the end region of the bolster. This may be seen by looking at the end of
the bolster from
below, in which the flat central portion of the bottom flange is approximately
the same width as
the broader portion of the bottom flange at the inboard commencement of face
124, and then
necks down to a narrower portion according to angle 0. When viewed from below,
the end
portion of the bottom flange may have a cruciform shape in which the cross arm
is defined by
the lands under the middle spring seats, and the stem is tapered to be broad
at the distal ends, and
narrow at the waist, the taper on the stems being that of angle 0. It may be
that only the inboard
stem of this cruciate form is tapered. In this embodiment, the bias of angle p
may tend to urge
the inboard and outboard dampers laterally toward each other.
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The outboard margin of side bearing seat 78 may be located at a station of
bolster 24
measured along axis 25 that corresponds roughly to the station of the abutment
surface 136 of
inboard bolster gib 112. Inboard of bolster pocket 120 and gib 112, bolster 24
may have reliefs
140. Relief 140 may be located generally abreast of seat 78. Each relief 140
may be in the
nature of an alcove, or socket, or pocket, 142 let inwardly from the sidewall,
and may be such as
to permit the introduction of a tool head, such as an open end or box-head
wrench, or a ratchet
and socket, to provide direct access to the underside of bore 86, 88 through
which the mounting
hardware of the side bearing may be introduced, with a nut bearing on the
underside of upper
flange 72 as at the location identified as 144. At this location, top flange
72 of bolster 24 may be
wider and substantially thinner than bottom flange 96, as shown by comparison
of thicknesses ti
and t2 in Figure 3d. There may be an open cavity, or passage 146 between webs
148 and 150 at
this location.
In the region of relief 140, the web portions 148, 150 of web sidewall
portions 56, 58
may deviate transversely inwardly under the region of side bearing seat 78 and
may define the
inner wall of pocket 142. This deviation may carry portions 148 and 150 inward
of, and between
bores 86, 88 of the mounting fittings of the side bearings. Whereas the
distance between
sidewall portion 56 and sidewall portion 58 immediately inboard of this
location may be
designated as Si, the gap width between web portions 148 and 150, designated
as a 82 may be
less than 2/3 of that width, and may be less than half of ol. Bolster 24 may
be free of any other
vertical web or other reinforcement supporting seat 78 other than web portions
148, 150. That is
to say, side bearing seat 78 may have a width 'W' between inboard and outboard
margins 152
and 154. The arc length of web portions 148, 150, as measured at the middle of
the thickness of
the wall, is greater that width W, and may be in the range of 5:4 to 2:1 times
as great. Expressed
alternately, the gap Si' between web portions 148, 150, being the minimum gap
width under
seat 78, and along the line of centers of bores 86 and 88 may be less than
half the length `L' of
seat 78, and less than half the length between the centers of bores 86 and 88.
Alternatively put,
if seat 78 has an area of L x W, then web portions 148 and 150 may be said to
divide that area
into three regions, identified as a central region 'A', lying between the
webs, and lateral regions
'B' and 'C' lying transversely outboard of the arc length center lines of web
portions 148 and
150. The sum of the areas of 'A', 'B' and 'C' equal 100% of L x W. Regions 'B'
and 'C' may
be of equal area. The ratio of the area of region 'B' to the area of region
'A' may lie in the range
of 2:3 to 2:1, and in one embodiment may be about 3:4, (+/- 20 %). In another
way of
expressing this, it may be that no point in the area LW lies more than 2/5 L
from the nearest
underlying vertical web, and, in one embodiment, this distance may be about
1/3 of L.
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In the central region of sidewall portions 56 and 58, there may be brake rod
apertures
156, 158. Aperture 156 in sidewall portion 56 may be aligned with aperture 158
in sidewall
portion 58, thereby making a fore-and-aft passageway through bolster 24. The
profiles of these
apertures 156, 158 may be formed with corner radii tending to be larger than
may formerly have
been used, and may tend to provide a larger passage for brake equipment, and
may also tend
toward lower stresses, and, to the extent that less material may be used, may
provide a measure
of lightening. It is thought that lower stresses in these features may tend to
lead to a greater
fatigue life. It may be noted that the panel 160 in which apertures 156 is
formed is bounded on
the inside by reinforcements. Bolster 24 may include a number of internal
features. Starting at
the mid-span centerline 27, there is a first lateral feature indicated as 160.
A second lateral
feature 162 is located in an inclined plane running from, roughly, the root of
the transition of the
lower flange (i.e. where mid-span portion 100 and inclined region 102 meet) of
the center plate
bowl rim 73 and the long axis 25 of symmetry of bolster 24 more generally. A
third feature,
indicated as 164, is a reinforcement feature extending in the long direction
of bolster 24 on the
underside of center plate bowl 74.
Feature 160 may include a substantially planar web member 166 that runs
between
sidewall portions 56 and 58 in a vertical plane, such as the mid-span plane or
centerline 27,
perpendicular to long axis 25 of bolster 24. Web member 166 may be joined
along one
upwardly extending edge or margin 168 to sidewall portion 56, and along
another upwardly
extending edge or margin to sidewall 58. Web member 166 may have feet 172 and
174 rooted in
lower flange member 96, those feet bracketing a relief in the nature of an
opening 176. Web
member 166 may also have upper margins 178, 180 that merge into the underside
of upper
flange 72 in the region of center plate bowl 74. Web member 166 may also
include, or support,
a king pin socket fitting. That is, the king pin bore, namely accommodation
76, is formed
downwardly through the base of center plate bowl 74, along the vertical, or z-
axis, at the
intersection of the longitudinal and transverse planes of symmetry of bolster
24.
Accommodation 76 extends centrally into what would otherwise be the center of
the mid-plane
of web 166. However, web 166 has, in its upper region adjacent the base of
center plate bowl 74
and reinforcement 164, two opposed bulges 184 that stand proud to either side
of the rest of web
166. Bulges 184 surround bore 76 and co-operate to define the centerplate king
pin socket. At
the lower extremity of bulges 184 there is a penetration, or aperture 186
formed through web
166, to permit a cotter pin to be inserted through the tip of the king pin,
thus discouraging its
escape.
Feature 162 may be identified as a reinforcement or stiffener, and, in one
embodiment,
CA 02510057 2013-03-08
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may have the form of a rib, vault or arch, having a first ascending portion
190 protruding
inwardly of sidewall portion 56, and running from a root in lower flange
member 96 fully
upwardly to merge into a transversely extending upper portion 192 that
protrudes downwardly
from the substantially planar upper flange 72, that upper portion 192 having
an arched lower
curvature. Upper portion 192 also merges into a second ascending portion 194
that protrudes
inwardly from sidewall portion 58. Second ascending portion 194 may be mounted
symmetrically opposite to first ascending portion 190. First and second
ascending portions 190
and 194, and upper portion 192 may co-operate to form an arch, and that arch
may aid in the
distribution of the relatively concentrated loads received at centerplate bowl
74 into the webs of
the bolster, such as sidewall portions 56 and 58, and into the lower flange
member 96.
It may be that rim 73 of center plate bowl 74 may be generally circular on the
inside, but
may include reinforced end portions as indicated at 185. Rim 73 may include
squared-off lugs
or corner portions 187, 189 such as may be thicker than the radial thickness
of rim 73 elsewhere,
such as at 91 at the mid-span centerline. The squared-off end portions may
tend to run
substantially parallel to upper portion 192 and may tend to be spread loads
thereinto. The
rectangular reinforced shape of these reinforced corner lugs may be of
substantially the same
width as the upper flange (+/- 15 %), and may have a length substantially the
same as the outer
diameter of rim 73 (+/- 15 %). The depth, or vertical thickness of the body of
the lugs may
correspond generally to the height of center plate bowl rim 73. That is, the
thickness may be
greater than about 1/2 the rim height, or half the center plate bowl depth, to
about the same as the
center plate bowl depth, or to about such thickness as make the top of the
lugs, or corner portions
187, 189 tend to be flush with, or slightly shy of, the top surface of rim 73.
The top of the corner
lug portions may taper away from rim 73 and the taper may be relatively
slight.
The members of feature 162 may define an opening, passage, or aperture 201
between a
first chamber, sub-chamber, or space or cavity 200, and a second chamber, sub-
chamber or
cavity, 202. Cavity 200 may be bounded by features 160 and 162, upper flange
72, lower flange
96 and sidewall portions 56 and 58. It may be noted that bolster 24 may have a
brake system
dead lever fulcrum pad (and bolt fittings), indicated generally as 198, to
which the brake arm
dead lever 197 may be mounted. Pad 198 may be located near the top of sidewall
56 or 58, and
may be such that the bolt fittings 161 straddle item 162, with the pad profile
seating in line with
item 162. Sub-chamber 202 lies outboard of feature 162 and is bounded by upper
flange 72,
lower flange 96 and sidewall portions 56 and 58. Sub-chamber 202 may extend
along axis 25 to
end at the narrows formed between web portions 148 and 150.
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Feature 164 may be identified as a reinforcement or stiffener merging into and
protruding
downwardly from upper flange 72 under the base of the center plate bowl 74.
Feature 164 may
be termed a rib or a load spreader, and may have a narrow portion, or waist
203, adjoining
feature 160, and may flare to a wider portion, or root 205, merging into the
upper portion 192 of
feature 162. When viewed as a whole, the opposed features 164 and feature 160
may, taken
together, have a cruciate plan form, such as may tend to support or stiffen
the base of the center
plate bowl, with the arms of the cross-shaped reinforcement structure
radiating from the axis of
the center plate bore. The thickness, or depth, of feature 164 may be
comparable to the thickness
of upper flange 72 in the region of centerplate bowl 74 more generally. This
thickness may be in
the range of 1/2 to 5/3 the thickness of flange 72 at the base of the center
plate bowl. The depth of
feature 164 may be such as not to obstruct the passage opening defined by
apertures 156 and
158.
As described, truck bolster 24 is a substantially hollow beam, having a
generally box-
shaped cross-section defined between the upper flange portion 52, the lower
flange portion 54,
and the first and second web portions. The box beam section so defined is one
of varying depth
and width. The internal reinforcements, such as items 160 and 162 are internal
shear transfer
reinforcements. These shear transfer reinforcements each have a force transfer
connection to
said first and second webs (the merging of the cross-wise web into the webs of
the beam in the
one case, and the merging of the column legs into the webs of the beam in the
other), and another
portion having a force transfer connection through which center plate bowl
loads are received.
The third internal reinforcement, feature 164, acts as a load carrying, or
spreading rib that
underlies and reinforces the centerplate bowl, while sharing its load between
the top of the arch
of feature 162 and the upper region of feature 160.
In the region of cavity 202, which is to say, that region of bolster 24 lying
outboard of
internal shear transfer reinforced 162, it may be that not only is there an
absence of
longitudinally running vertical shear webs linking top flange 72 with bottom
flange 96, but, there
may be an absence of longitudinally running ribs generally. This may tend to
permit the use of a
core for cavity 202 that is free of re-entrant features.
As noted above, bolster 24 may include brake rod apertures 156 and 158.
Apertures 156
and 158 may be of non-standard size. The Association of American Railroads
(AAR) standard
S-392 provides standard dimensioning for brake rod apertures to accommodate a
standard brake
rod layout, and to accommodate a WABCOPACTM or NYCOPACTM brake arrangement.
This
standard S-392 is incorporated herein by reference. In general, the apertures
provided for
CA 02510057 2013-03-08
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WABCOPACTM or NYCOPACTM brake arrangements have corner radii that are
indicated as
having a maximum radius of 2 inches. Standard brake rod openings are indicated
as having
corner radii of 2 inches. WABCOPAC brake rod openings are shown as having an
area of the
order of somewhat less than about 25 sq. in., maximum, and standard brake rod
openings are
shown as having an area of somewhat less than about 34 sq. in. Similarly,
there may have been a
tendency in the past to desire to minimize the size of the brake rod openings.
These openings
may not always tend to be overly generous in size, and the installation of the
brake rods may
sometimes tend to be a bit of a close fit. For example, one "conventional
brake rod opening"
identified in AAR standard S-392 has a generally parallelogram like shape
being about 4 5/8"
wide, about 7 1/8" high, and having corners with 2" radius and whose upper
portion is offset
laterally about 7/16". In another example standard S-392 shows a WABCOPACTM
brake rod
opening that is generally rectangular, having a width of about 3 1/8, a height
of about 8 5/8" and
rounded corners having a radius that is, at most, 2". By contrast, apertures
156 and 158 may be
rather larger. Apertures 156 and 158 may tend to employ rather larger radii of
curvature in one,
another, or all corners. Apertures 156 and 158 may tend to have a profile that
encompasses both
the standard brake rod profile and the WABCOPACTM or NYCOPACTM profile, such
that either
type of brake may be installed. Apertures 156 and 158 may tend to be more
rounded than the
standard and WABCOPACTM or NYCOPACTM brake rod apertures identified in AAR
standard
S-392.
Aperture 156 (158 being substantially identical, but of opposite hand) is
formed in a first
panel region 204 of sidewall 56. First panel region 204 is bounded by upper
flange 72, lower
flange member 96, mid span transverse feature 160, and intermediate transverse
feature 162.
The profile of aperture 156 may be unusually large, and may provide increased
space in which to
install brake equipment. First panel region 204 may be thought of as being
generally
quadrilateral, having a first side or edge 210, being substantially
horizontal, and adjacent to or
associated with the edge of upper flange 72; a second side or edge 212, being
substantially
vertical, running along, or being associated with the edge of feature 160; a
third side or edge 214,
being predominantly horizontal, running along or being associated with, lower
flange member
96; and a fourth side or edge 216 running along, or being associated with the
inclined
reinforcement feature 162. These associated sides and edges may meet at
respective corners 211
(being the upper inboard corner between 210 and 212), 213 (being the lower
inboard corner
between 212 and 214), 215 (being the lower outboard corner between 214 and
216), and 217
(being the upper outboard corner between 216 and 210).
The profile of aperture 156 may be identified as 220. Profile 220 may have an
overall
height indicated as h156, and an overall width indicated as w156. Height h156
may exceed 3/5 of
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the depth of bolster 24 measured over the top and bottom flanges namely items
72 and 96 (but
excluding the height of the center plate bowl rim). In one embodiment, height
h156 may be in
excess of 2/3 of this height. Expressed differently, h156 may be greater than
10 inches, and may,
in one embodiment, be about 10 1/2 inches. Width w156 may be of a magnitude
greater than 2/5 of
the magnitude of the overall height over the top and bottom flanges (i.e.,
items 72 and 96), and,
in one embodiment, may be about half that height. In one embodiment w156 may
be in excess of
6 1/2 inches. In another embodiment w156 may be in excess of 7 inches. In
another embodiment
W156 may be about 7 7/8 inches (+1/8, - 1/4 inches). The aspect ratio of
aperture 156 may be such
that the ratio of width w156 to height h156 is in the range of about 3:5 to
about 4:5, and, in one
embodiment, it may be greater than about 2/3; and in another it may be about
3:4 (+/- 10%).
Profile 220 may have a perimeter arc length, P, and an enclosed area A156. A
characteristic
dimension Dh, may be defined as Dh= 4A156/P. In one embodiment, Dh may be
greater than 6
IA inches, in another embodiment it may be greater than 7 inches, and in
another embodiment
may be greater than 8 inches. In one embodiment Dh may be about 9 inches. An
equivalent
circular diameter may be defined as De = square root of [4A/7r]. A measure of
roundness of an
aperture can be defined by the ratio of Dh to Dc. For a circular opening, this
ratio of Dh/Dc is
100 %. In one example, aperture 156 may have a ratio of Dh/Dc that is greater
than 95 %. In
still another embodiment this ratio may be in the range of 97 % or more, and
99 % or less. A
further measure of comparative roundness may be obtained by defining a
characteristic diameter
Dp = (P/7r) where it is approximately 3.1415926. In some embodiments, the
ratio of Dh/Dp may
be greater than 90 %, in other embodiments may be greater than 15/16, and in
one embodiment
may be greater than 95 %. As another measure of the unusual size and openness
of aperture 156,
area A156 may be compared to the overall area, Ar, of region 204, as measured
to the middle
fibres of the bounding features 72, 96, 160 and 162. In one embodiment the
ratio of A156:Ar
may be greater than 3/10, in another embodiment it may be greater than 3/8,
and in one
embodiment may be up to about 7/16 (+/-). In absolute terms, A156 in some
embodiments may
be greater than 45 sq. in., in other embodiments may have an area of greater
than 60 sq. in., and
in one embodiment may have an area of greater than 65 sq. in. Alternatively,
by comparison to
the corresponding conventional brake rod opening defined in AAR S-392, A156,
may be half
again as large, or more, than the corresponding WABCOPACTM opening on one
hand, or the
corresponding conventional brake rod opening on the other, defined in S-392.
In one
embodiment, A156 may be as much as, or more than, 80 % larger in area than the
corresponding
conventional brake rod opening defined in S-392, and may be more than double
the area of the
corresponding WABCOPACTM opening of S-392.
Profile 220 may include a number of corner radius regions. Those corner radius
regions
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may include an upper inboard corner radius region 222, (such as may be
associated with, or
closest to, corner 211); a lower inboard corner radius region, 224, (such as
may be associated
with, or closest to, corner 213); a lower outboard corner radius region 226,
(such as may be
associated with or closest to, corner 215); and an upper outboard corner
radius region 228, (such
as may be associated with, or closest to, corner 217). Profile 220 may also
include tangent
portions between one or more pairs of two adjacent arcuate corner regions. By
way of example,
one tangent portion 230 may run between corner radius regions 222 and 224.
Tangent portion
230 may be of substantial length, perhaps being as much or more than a quarter
as long as the
overall height, h156, of aperture 156. Tangent portion 230 may run at an angle
with respect to the
vertical, and that angle may be such that the lower end of tangent 230 may be
closer to item 160
than is the upper end. In one embodiment, tangent portion 230 may be between 4
and 5 inches in
length. Tangent portion 230 may be the longest of any tangent portions of
profile 220. Tangent
portion 230 may be longer than the shortest radius of curvature of profile
220, but shorter than
the largest radius of curvature. Profile 220 may also include a tangent
portion 232 between
corner radius regions 224 and 226 and another, or other tangent portions
between regions 226
and 228; and between regions 228 and 222. There need not be tangent portions
between each
pair of radiused corner regions. In some embodiments, the curved portions of
two corner
portions may merge into one another at, for example a spline fit or mutually
tangent point of
slope continuity. Alternatively, the tangent portion between two arcuate
portions may be of
relatively short length, as for example, when the length of the tangent
portion is between zero
and about 1 or 1 1/2 inches or so. In this context, the term "tangent point"
is intended to include
both true tangent intersections and joining tangent portions of small extent.
For example, corner
region 224 and corner region 226 may meet or be connected at or near the
location indicated as
225, be it a common tangent point, or a joining tangent portion of small
extent. Similarly, corner
region 226 and corner region 228 may meet or be connected at or near the
location indicated as
227, be it a common tangent point, or a joining tangent of small extent.
Similarly too, corner
region 228 and corner region 222 may meet or be connected at a common tangent
point, or at a
joining tangent of small extent.
It may be that each of the arcuate corner radius regions 222, 224, 226 and 228
has a
predominant radius of curvature over a portion, or all, thereof It is not
necessary that these
corner radii be formed on circular arcs. They could, for example, be formed on
parabolic,
elliptic, or hyperbolic arcs, or on a number of circular arcs of differing
radii run (i.e., spline fit)
into each other. However, as at least an approximation, these corner radius
regions may be
considered to have a dominant radius of curvature, or, where many radii of
curvature are
employed, or the radius of curvature varies as a function of arc length
position, then the mean
CA 0 2510 057 2 0 13-0 3-0 8
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radius of curvature for the corner radius region. Those radii of curvature may
be identified
respectively as R222, R2241 R226 and R228. Employing the dominant radius of
curvature of the
corner radius region, or the equivalent, or mean, radius of curvature of the
section in the event
that a parabolic, hyperbolic, or elliptic curve is employed, it may be that
the radii of curvature of
the corner regions differ. It may be, for example, that each corner region has
a different radius of
curvature. It may be that the dominant radius of curvature in the upper
outboard corner may be
the largest of the radii of curvature, identified as R228. Expressed
differently, it may be that the
least sharply curved corner region of profile 220 may be the upper outboard
region. It may be
that the dominant radius of curvature of the upper outboard corner region is
greater than half of
Dh, and may be greater than half of Dc. In one embodiment, R228 may be in the
range of 6/5 to
5/3 as large as Dc. In one example the largest dominant corner radii, be it
R228, for example,
may lie in the range of greater than 5 inches, and may be in the range of 5
1/2 to 6 1/2 inches, and
in one embodiment may be about 6 inches. R228 may be larger than the longest
tangent portion
of profile 220.
By contrast, the most sharply curved region of profile 220 may be in the upper
inboard
corner region, such that the smallest radius of curvature may be radius R222.
Radius R222 may be
more than 3/10 of Dh or Dc, and may be less than 2/5 of Dh or Dc. In one
embodiment, R222
may be more than 5/16 of Dc or Dh, and may be less than 3/8 of DC or Dh.
Expressed
differently, the smallest dominant radius, such as may be R222, may be more
than 1/3 and of less
than 3/5 of the largest dominant radius, such as R228, for example, and in one
embodiment may
be more than 3/8 and may be less than half of the largest dominant corner
radius. Alternatively
In one embodiment R222 may be less than 3 1/2 inches, and in another
embodiment it may be less
than 3 inches. In still another embodiment it may be about 2 3/4 inches. Any,
or each of these
radii, or all of them, may be larger than the 2" radius indicated in AAR S-392
for either the
standard or WABCOPAC opening, and may be larger than 2 1/2 inches.
In one embodiment, R224 may be larger than R222, and smaller then R228. R224
may be
between 3 and 4 inches, and, in one embodiment may be about 3 1/2 inches. R224
and R226 may
be of roughly comparable size. R226 may be somewhat larger than R224, maybe in
the range of 3
1/2 to 4 1/2 inches, and in one embodiment may be about 3 3/4 inches (+/- 1/2
inch).
The angular arcs of the respective corner portions need not necessarily be
equal, and need
not necessarily be 90 degrees. For example, corner portion 222 may extend over
an arc in excess
of 90 degrees. Corner portion 228 may extend over an arc of greater than 90
degrees. Corner
portion 226 may extend over an arc of less than 90 degrees. The overall shape
of profile 220
CA 02510057 2013-03-08
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may be generally D-shaped, or kidney shaped. One side may include a straight
edge of
substantial extent, while the other side may have a predominantly bulging
shape. Profile 220
may have an apex. That apex may be identified as 231. Profile 220 may also
have a centroid,
identified as CD. Apex 231 may lie closer to the central vertical mid-span
plane than the
centroid. Expressed somewhat differently, apex 231 may be displaced laterally
from tangent
portion 230 a distance that is less than half the overall width of profile
220, and, in one
embodiment, less than 3/8 of the width of profile 220, where the lateral
displacement is
measured perpendicular to tangent 230.
Leaving aside bores for mechanical fasteners, such as fittings 161 for the
brake dead
lever pad 198, sidewalls 56 and 58 may be substantially free of openings
interrupting the web in
the intermediate region 64 between reinforcement item 162 and a station lying
abreast of the
inboard edge of the side bearing seat 78 inboard of the end region 66. That
is, particularly given
the presence of a tool socket (i.e., relief 140) immediately abreast of, and
adjacent to the bores
86, 88 of side bearing seat 78, sidewalls 56 and 58 may not require large
intermediate openings,
such as may be in the nature of access or lightening holes or penetrations,
such as might
otherwise permit a person to reach a hand or arm inside bolster 24 to install
the nuts of the side
bearing fittings. Expressed differently, to the extent that there is no
penetration through either
sidewall 56 or 58 to give access to the side bearing fitting, but only a web
deviation, it may be
that there is no lightening hole or access hole web penetration in webs 56 and
58 at all outboard
of reinforcement 162 (and hence, outboard of aperture 156). As such, that
region, identified as
sidewall web panel 236 may be free of lightening or hand-access through hole
openings.
Considering the section ' 3f-3f , it may be noted that sidewall portions 56
and 58 may not
necessarily stand in a vertical plane in the region of item 160. Rather, they
may be inclined
outwardly at an angle, designated in the illustrations as angle 9, being wider
apart at the top than
at the bottom. The overhang of the center plate bowl rim at the mid-span
section, as shown, for
example, in Figure 3f, may then tend to be reduced. This can be seen in a
number of ways. For
example, taking the width W238 between the points of tangency 238 of the upper
radii 240 as a
proportion of the inside diameter of the center plate bowl, W238 may be in the
range of 85 to 100
% of that diameter, and in one embodiment may be in the range of 87 to 92 % of
that value.
Alternatively, if construction lines are drawn from the tangent of the slope
of the web on the
mid-span centerline to intersect the bottom wall of the center plate at a
location 242 (or the top
surface of the base portion of the center plate liner, if one is used) the
width at that intersection,
identified as W242 may, in one embodiment be more than 7/8 of the center plate
bowl inside
diameter, and, in one embodiment may be more than 90 % of the center plate
bowl inside
CA 02510057 2013-03-08
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diameter. A third way of observing this is in the angle q from the vertical of
the point of
tangency 244 of the radius on the underside of the center plate bowl on the
mid-span section, as
seen in Figure 3f for example. In a conventional truck bolster, this angle may
be roughly 90
degrees. This angle may be less than 75 degrees, and in one embodiment may be
about 60 to 70
degrees, and may yield a distinctly less sharp transition from the center
plate bowl to the web at
that location. It may be that while upper flange 72 is widening from the
juncture with center
plate bowl 74, bottom flange 96 may be narrowing from the mid-span centerline
to a location
generally abreast of the inboard gibs 112.
Considering the inside of truck bolster 24, it may be that bolster 24 is
substantially free of
longitudinally running vertical webs such as might other wise extend between,
and connect,
bottom flange 96 and top flange 72 in either the deep bay of sub cavities 200
under centerplate
bowl 74, or in the next adjacent bay of sub-cavity 202 between feature 162 and
the inboard gib
or side bearing location. That is, in these locations, rather than having
internal, longitudinally
running full height shear web panels, truck bolster 24 may tend to have
comparatively large open
cavities, namely 200 and 202. Bolster 24 may be free of such vertical webs
running along the
long centerline, and may also be free of pairs of such vertical webs, spaced
symmetrically to
either side of the long centerline.
Furthermore, outboard of the station of side bearing seat 78, in contrast to
more
conventional designs in which the bolster end may include vertical internal
webs running
longitudinally, truck bolster 24 may have a sub-cavity 250. That is, between
the stations of the
inboard and outboard gibs 112 and 114, or, alternatively put, outboard of the
station of inboard
gibs 112, truck bolster 24 may have a lengthwise continuous cavity namely sub-
cavity 250. That
cavity, when viewed in the sectional plan view of Figure 2c, for example, may
run behind the
bolster pockets, and may have a generally hour-glass shape, such that each of
the sidewalls is
spaced a first distance Ei from the truck bolster centerline generally abreast
of the inboard gib
112, a second distance E2 at the outboard end adjacent the outboard gib 114,
and a third distance
E3 at an intermediate location between the inboard and outboard gibs, that
third distance E3 being
less than either the first distance Ei or the second distance E2. In some
embodiments Ei and E2
may be the same, or substantially the same. The location of the minimum
distance, E2 , may be
mid way between the inboard and outboard gibs 112 and 114, and may be between
the inboard
and outboard bolster pockets 120 and 122. The location of the minimum distance
may lie over
the center of the upper spring seat pattern, that location being exactly mid
way between the
inboard and outboard bolster pockets 120 and 122. Over this distance, the sub-
cavity 250, in
plan view, is free from sharp changes in section width, and is free of small
radii of curvature. It
CA 02510057 2013-03-08
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may be noted that passage 146 connects sub-cavity 250 with the adjacent sub-
cavities 200 and
202 in the central bay between feature 160 and feature 162, and in the next
adjacent bay between
feature 162 and the location of the inboard gib 112. To the extent that these
bays are in
continuous fluid communication, and to the extend that feature 160 has a
through aperture, such
as relief 176, all of the sub-cavities are interconnected, and in those
embodiments in which truck
bolster 24 is a steel casting, the number of casting cores required my be
reduced, as compared to
the number of cores that may previously have been employed in other truck
bolsters; and the
cores may be interlinked, or joined together such that there may be more
precise control over the
positioning of the cores in the bolster mold, both of one core relative to
another, and of the cores
themselves relative to the mold. It is thought that this may tend to encourage
or permit more
consistent reproduction, or production to closer tolerances from one truck
bolster casting to the
next.
Some known truck bolsters, such as the Barber 52-HD, may have a profile
generally
similar to that shown in Figure 4a. In this bolster A20, the bottom flange
transition A24 from
the bottom flange end portion A22 of bolster A20 to the inclined portion A26
of the tapering
intermediate portion A 28 of bolster A20 includes a relatively small radius
first curve, A30,
whose center of curvature lies below the bottom flange, and then a second
curve A32, having a
center of curvature lying above the bottom flange. There is a point of
inflection A34 between
the two curves, and a sloped, or tangential, portion A36 running on the slope
of the deepening
transition section A38. The angle of this slope from the horizontal is
identified as 436. There is
a further radius of curvature A40 where the transition section meets the deep
central portion of
the bolster A42, the center of curvature of radius A40 lying above the bottom
flange.
A smoother, gentler transition may tend to yield a stress field in the flange
that is subject
to less sharply changing stress field gradients. In that light, referring to
Figure 4b, in one
embodiment, truck bolster 24 may have a relatively smooth, large radius
transition at the
junction of the tapered region 64 or portion of bolster 24 to the end region
66 or portion. This
may be expressed in a number of ways. First, the sloped portion 254 of lower
flange 96 may lie
on a tangent plane 256, as viewed in profile, tangent plane 256 lying at an
inclined angle 1456
relative to the horizontal. It may be that the generally downwardly facing
surface 258 of sloped
portion 254 of bottom flange 96 is substantially planar, in whole or in part,
that plane extending
perpendicular to long axis 25 of truck bolster 24 on the incline of angle
)456. The radius of
curvature R260 of the arcuate corner portion 260 of the outside fibre of the
bottom flange 96
between deep central portion 262 and sloping portion 254 has a center of
curvature lying above
plane 256. It may be that arcuate portion 260 is tangent at its ends to the
substantially horizontal
CA 02510057 2013-03-08
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central bottom flange portion 262 (at location 261), and to sloped portion 254
(at location 267)
respectively. It may be that over this arcuate portion 260, both the first and
second derivatives
(i.e., dz/dx, and d2z/dx2) of the curve are positive. At the outer, upper end
of sloped portion 254,
there may be another arcuate portion, 264, that may be formed on a radius of
curvature identified
as R264, having a center of curvature lying below plane 256. It may be that
arcuate portion 264 is
tangent at its respective inboard and outboard ends to sloped portion 254 and
end portion 266 of
bottom flange 96. It may be that over this arcuate portion 264, the first
derivative, dz/dx, is
decreasingly positive, and the second derivative, d2z/dx2, is negative.
In contrast to the design of Figure 4a, the transition from the sloped portion
to the end
portion may be free of the third radius of curvature, or, expressed
differently, may be free of any
portion for which the second derivative, d2z/dx2 is positive. Expressed
differently again, bolster
24 may be such that the profile of the bottom flange outboard of planar sloped
portion 254 (i.e.,
outboard of the end point of the tangent section, indicated at 268), does not
include any portion
extending upwardly of plane 256. The radius of curvature R264 at the junction
of inclined portion
254 of lower flange 96 and the end portion 266 of lower flange 96 may be
greater than the
vertical through thickness 46 of the end portion 66 of bolster 24 on
centerline 25 at the station of
the middle of the upper spring seat 107, which, when the bolster is at rest in
a neutral position
may tend to coincide with the centerline of the side frame pedestals,
indicated as 270. In one
embodiment, radius R264 may be greater than 4 inches. In another embodiment,
R264 may be
greater than 6 inches. In another embodiment R264 may be in the range of 6 to
15 inches. In
another embodiment, R264 may be in the range of 8 to 12 inches. In another
embodiment, R264
may be about 9 Y2 inches (+/- 1 inch). Expressed yet differently again, that
radius, R264, may be
greater than 4 inches, and may be greater in magnitude than half of the main
radius of curvature
R260 between the deep central portion and the inclined portion. In one
embodiment the ratio of
R264: R260 may lie in the range of 1:3 to 6:5, and may in one embodiment be in
the range of 1:2
to 9:10. In one embodiment R260 may be about 12 inches (+/-20 %). In one
embodiment R264
may be about 91/2 inches (+/-20 %). Expressed yet differently again, in one
embodiment, all of
the spring seat retainers 105 may lie below the inclined plane 256, or more
simply, the entire
upper spring seat 107 may lie below plane 256. It may also be that in one
embodiment, the slope
of the incline, namely angle i456 may be greater than 20 degrees from the
horizontal. In another
embodiment 1.256 may be greater than 23 degrees. In another embodiment, )256
may be about 27
degrees (+/- 2 degrees).
In an alternate embodiment, tangential, sloped portion 254 of the bottom
flange 96 may
be very short, or, may be of zero length. That is, the arcuate portions 260
and 264 may be
CA 02510057 2013-03-08
- 27 -
formed to meet at a common point of inflection (i.e., the distance between
points 267 and 268
decreases to zero). In such case, plane 256 may be defined as being the plane
that is normal to
the second derivative, d2z/dx2, of either arcuate portion at the point of
inflection, those second
derivatives being defined as collinear at the point of inflection.
While bolster 24 may be used in trucks of various sizes and capacities, it may
be that it
may be employed in a truck of an AAR rated capacity of at least 70 Tons.
Alternatively, it may
be employed in trucks of at least 100 Tons rating. In the further alternative,
it may be used in
trucks having an AAR rating of either 110 Tons or 125 Tons. Expressed somewhat
differently,
bolster 24 may be rated to carry a central vertical load of at least 115,000
lbs. In another
embodiment, bolster 24 may be rated to carry a vertical load of at least
130,000 lbs. In still
another embodiment, bolster 24 may be rated to carry a load of at least
145,000 lbs.
Various embodiments have been described in detail. Since changes in and or
additions
to the above-described examples may be made without departing from the nature
or scope of the
invention, the invention is not to be limited to those details.
