Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
2Q47400
I~PRO~ED FREIGHT RAILCAR TRUCR AND BOLSTER
FOR OUTBOARD SUPPORT OF CAR BODY
BACKGROUND OF THE INVENTION
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This invention relates to an improved freight railcar
truck and more particularly is directed to an improved truck
bolster having distal ends that extend outward of the truck
side frames to support the weight of a carbody at its side
sills.
Although there are other de~igns for freight railcar
trucks, the va~t prePonderance of freight car truck~ in
domestic U.S. service are known as three piece outboard
bearing trucks. That i8 to say the truck comprises three
principal part~, namely a floating truck bolster laterally
connecting two side frames; and the side frames are mounted on
two wheel~ets each including two flanged wheels mounted on an
axle. The truck bolster is spring ~upported on what is
commonly referred to as a ~secondary suspension~ system for
vertical cushioning movement on the side frames. Bearings are
mounted on the axles adjacent each wheel and the ends of each
side frame are primarily suspended between corre~ponding
bearings on the two axles. In freight car truck con~truction
there iJ no significant vertical spring movement of the
primary suspension. Where the bearings and qide frames are
located outboard of the wheels, the truck i~ referred to as
outboard bearing.
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In moqt rail car a~qemblieq two trucks are required, one
at each car end, and the car under frame include~ longitudinal
qide 9ill9 and transverqe body bolqters, the latter being
located directly above the truck bol~ters and serving to
tranqfer the car load to center bearing plate~ (or bowl~) at
the geometric center of the truck bolsters. There is usually
al30 a center ~ill at the ends of the rail car interqecting
the body bolster~ which center ~ill9 contain coupling gear and
~erve to transmit longitudinal draft and buff force~ to the
car body bolster and thence to the truck bol~ter.
Example~ of other rail car truck designs may be found in
the following United State~ patents:
I. Rail car trucks connecting the car body directly to the
truck side frame:
No. 516,935 springs extend directly above the ~ide
frameq to support the car body without a truck
bol~ter:
No. 900,760 ~prings extend directly upwardly from
each ~ide frame to the car body and a truck
cro~spiece is rigidly fastened to both side frameq;
No. 2,011,918 spring~ support each side frame on
axles outboard of the wheel~ with rigid cross beam~
between the side frames, and the car body ~it~ on
roller~ carried by the side frames: and
No. 3,961,584 springs supporting the car body extend
upward from ~ide frame~ that are bolted to a
horizontal cro~s plate.
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II. Rail car truck9 supporting the car body uPon bol~ter ends
outboard of the side frames:
No. 731,626 a passenger car body is supported on
springs carried on a second transverse beam outboard
of side frames that are otherwi~e connected by a
truck bolster (a second embodiment for freight carq
supports the car body on springs seated on a truck
bolster inboard of the wheels);
No. 1,211,789 levers pivotally mounted on side
frames support the car body on structures inward of
the side sills:
No. 4,237,791 an inboard bearing truck has a bolster
that carries car supporting pneumatic sPrings
outboard of the wheels.
III. Other:
No. 2,046,391 an inboard bearing truck ~upport~ the
car body on a bolster centerplate and has auxiliary
roller type side bearings on ends of the bolster
outboard of the wheels.
From the foregoing prior art and other knowledge of the
railroad industry it can be ascertained that freight car
construction, as contrasted to passenger car construction,
favors a minimum of truck parts and simplified suspension
systems so as to reliably carry heavy loads at minimum
operating expense and low original e~uipment cost. Simplicity
of design with minimum weight and number of parts will usually
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contribute toward those goals. Additionally the industry seeks
rail car dynamic stability for operating safety; and efforts to
lower a car center of gravity and to reduce car roll will
contribute toward that goal.
SUMMARY OF THE INVENTION
Therefore, the present invention provides a rail car truck
that will resist the tendency of a rail car body to roll from
side to side.
Also the present invention provides a rail car truck that
will enable weight reduction in the car body structure.
Also there is provided a freight rail car truck that
supports a car body at the side sills on the secondary suspension
system of a floating bolster.
The present invention provides an outboard bearing freight
car truck and truck bolster for carrying a car body at the side
sills thereof.
Accordingly, the present invention involves a unique truck
bolster for a three piece freight rail car truck wherein the ends
of a floating bolster extend outwardly beyond the side frames to
beneath the car sides to directly carry a car body at the body
side sills and thereby permit elimination of the heavy center
bearing and redesign of the car body bolster with consequent
weight savings.
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Specifically, there is provides an improved rail car truck
bolster comprising a box like body having upper and lower walls
and sidewalls therebetween;
a pin receptor centrally located in said upper wall; gibs on
said sidewalls spaced from said pin receptor, said gibs adapted
to position said truck bolster in respective sideframes of a
truck; distal ends on said bolster extending beyond said gibs
such that the entire weight of a railcar is supported entirely
outside said side frames at about the side sills of the railcar.
4a
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BRIEF DESCRIPTION OF THE DRAWINGS
Further objects and advantage~ will become apparent uPOn
reading the following detailed description of an embodiment of
the invention in conjunction with the drawingq wherein:
FIGURE 1 is a per~Pective view from beneath a car body
(partially qhown) and car truck incorporating the present
invention;
FIGURE 2 i9 a perspective view from above the car truck
of FIGURE 1 with car body removed;
FIGURE 3 i~ a partial (half) detail view of a truck
bol-~ter according to the present invention;
FIGURE 4 is a plan view of the bolster (half) of FIGURE
3;
FIGURE 5 i8 a sectional elevation view of the bolster
(half) of FIGURE 4;
FIGURE 6 is a perspective view of one bol~ter bearing
embodiment of the Preqent invention:
FIGURE 7 i8 a side elevation of the bol~ter bearing of
FIGURE 6;
FIGURE 8 i8 an end elevation of the bolster bearing of
FIGURE 6; and
FIGURE 9 iJ a perspective view of another embodiment of a
bol~ter bearing suitable for u~e in the present invention.
DETAILED DESCRIPTION OF THE INVENTION
As shown in FIGURES 1 and 2 a preferred embodiment of the
present invention i8 directed to a three piece outboard
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bearing rail car truck comPrising two ~ide frames generally
10, 12 and a unique tran~verse bolster generally 14 that
extends substantially the full width of a railcar and is
supported on a secondary suspension system comprising coil
springs 16, 18 mounted on the side frames 10, 12 respectively.
Each of the side frames, usually of cast steel, includes an
upper compression member 20, a lower tension member 22 having
a spring seat 24 and two pedestal jaws 26, 28. The latter are
supported upon journal bearings 34, 36 fitted upon a pair of
axle9 40, 42 outboard of wheel sets 44, 46 and 48, 50,
respectively.
According to the present invention the bolster 14,
preferably also of cast steel, has a box-like body 52 with top
wall 56, bottom wall 54 and interconnecting side walls 58. A
pin receptor 60 is centrally located in top wall 56 and two
distal ends 62, 64 extend outwardly of the body 52 at a
distance from receptor 60 beyond the side frames 10, 12. Each
distal end 62, 64 includes flat, horizontal, surfaces 68
adapted to directly carry a rail car body generally 80 at or
adjacent the side sills 82, 84 thereof. Preferably the
bolster also includes an interior web 66 parallel to and
central of the side walls 58.
As shown in FIGURES 3-5, the surfaces 68 of distal ends
62, 64 are provided with seats 70 to receive friction side
bearings generally 110 (more fully described hereinafter) to
permit controlled sliding movement between the bolster ends
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62, 64 and the railcar body 80. Preferably the seat~ 70 have
concave spherical qegment surfaces 74, qo a~ to receive convex
concentric under~urfaces on bearings 110, which permit the
bearings to tilt in all directions and thereby enable the
bearings 110 to be qelf-adju~ting to the railcar body 80. It
will al~o be seen in FIGURES 3-5 that the ends of bolqter 14
incline inwardly from top to bottom (so as to keep within the
American A_sociation of Railroads 3tandard clearance line at
track side) and accordingly it is advantageous to locate the
low point of seat qpherical ~urface 74 slightly offset
inwardly (toward the receptacle 60) from the center of the
concave seat 70. Additionally, it will be noted that the
qpherical surface 74 extends ~moothly to the horizontal
~urface 68 in a direction transver~e of the bolster 14 but in
the direction of the bolqter axiq is truncated by qhallow
transver~e arcuate wallq, namely an inner cylindrical wall 76
and an outer conical wall 78 both such arcuate wall~ having
radii from the center of pin receptor 60.
A~ illustrated in FIGURE 1, it i~ convenient to locate an
outrigger member 86 between each car side qill 82, 84 and the
corresponding bol~ter distal ends 62, 64. In the preferred
embodiment, the outriggerq 86 are permanently secured to the
car body 80 at the side sills 82, 84 and the underside of each
outrigger 86 may have a wear pad 88 that qlidingly rests on
the respective ~ide bearing 110 at each bol~ter end.
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The car load is thus su~ported on the diqtal end~ 62, 64
of bolster 14 and transmitted to the side frames 10, 12
through ~prings 16, 18. In accordance with prior three piece
trucks the bolster 14 i9 movable vertically within each side
frame between vertical columns 90, 92 and is provided with
inner and outer column positioning gibs 94, 96 and friction
shoe pockets 98. Since the present bolster 14 supports the
car load at its ends 62, 64, the vertical dimension of the
bolster at the pockets 98 is sliqhtly qreater than prior
bolsters to withstand higher bending moments and the side
frames 10, 12 and vertical columns 90, 92 are slightly higher
to accommodate the greater vertical dimension of the bolster
ends.
It will be understood that the present invention provides
for supporting the weight of a car body 80 at the side sills
82, 84 rather than upon a center sill 100 which heretofore has
been the standard practice for freight car construction. In
this way the car under frame structure may be simplified and
lightened and the need for a traditional transverse body
bolster above each truck bolster may be eliminated. The truck
bolster 14 thuJ does not require a center bearing bowl to
support the car body, however, a central vertical connection
such as a column or pin (not shown) is located between the
receptor 60 on bolster 14 and the car center sill 100 so as to
establish a center of rotation between truck and car body and
to transmit horizontal force~ between truck and car body.
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Since the bolster 14 will turn beneath the car body 80,
it i~ preferred to relieve the bolster di~tal end corners 102
~o that no part of the bolster 14 will extend beyond the car
~ide 9ill~ 82, 84 or the American Association of Railroad~
(AAR) ~tandard clearance line at track side during curving.
In one embodiment for light weight car bodieq each
friction qide bearing 110 received in ~eats 70 at the ends 62,
64 of bolster 14 i8 provided with a multi-friction mean~ that
functions to provide sufficient frictional engagement with
pads 88 to control truck hunting (transverse oscillation~)
even under no load (empty rail car) or low load conditions,
yet also allow for relative turning (truck curving) movement
under a fully loaded condition. This i~ accomplished with a
bearing member generally 110, shown in FIGURES 6-8, having a
major friction body 112 comprised of a relatively low friction
material quch as teflon coated machined qteel that has a firqt
relatively low friction coefficient Fl of about .05-.07, which
surrounds one or more ~econdary friction bodie~ 114 of
relatively higher friction material such as cast ~teel that
ha~ a second friction coefficient F2 of about .35. Each
secondary friction body 114 i~ received in a cavity 116 in the
major friction body 112 and i9 biased outwardly by a spring
118. ~oth major and secondary friction bodies 112, 114 have
flat upper friction surfaces or faces 120, 122 that bear
against the pads 88 on car body outrigger 86. It will be
understood that the frictional resi~tance to sliding motion
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between each bearing member 110 and corresponding pad 88 of a
loaded car will have two componentq. One component R-l will
be the product of the car weight (including load), the area of
friction face 120 of the major friction body 112 and the fir~t
coefficient of friction Fl. The second component R-2 will be
an e~sentially constant product of the force of spring 118,
the total area of -qecondary friction faceq 122 of the
qecondary friction bodies 114 and the ~econd coefficient of
friction F2. The second component is, by selected de~ign
parameters, made ~ufficient to control the tendency of a given
truck configuration to hunt at expected empty car operating
speeds.
In another embodiment for heavy weight car bodie~ and
general application, a bearing member generally 110', ~hown in
FIGURE 9, having a single friction means is received in each
~eat 70. The bearing member 110' comprises a solid body 112'
having uniform friction face 120' either coated with a low
friction material or supporting a pad 120a' of a low friction
material such as an ultra high molecular weight polymer or the
like.
Both bearing member embodiments generally 110 and 110'
are preferably in the form of a slightly arcuate body 112,
112' or shoe that is substantially congruent with the concave
seat 70 and have a convex and preferably spherical
under~urface 124 that is slightly ~maller and received in the
concave seat 70 on the surface 68 of each diJtal end 66, 64 of
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bolster 14. In thi9 way each bearing member 110 will be free
to tilt tran~versely and longitudinally of the car ~o a~ to be
qelf leveling against it~ respective Pad 88 under the weight
of the car body 80.
It will be seen in FIGURES 6-9 that for each embodiment
of the bearing member~ the body includes concentric arcuate
end walls 136, 138 and straight side walls 140, 142 extending
between the spherical undersurface 124 and the friction face
120. The arcuate end walls 136, 138 are formed to be
concentric with the respective inner cylindrical wall 76 and
outer conical wall 78 of a bearing seat 70 and the bearing
body 112 is sized to fit therein. Accordingly, for a bolster
of 9 foot 11 7/8 inch maximum dimension, the bolster distal
ends 62, 64 are 16.88 inches wide and terminate in outer arcs
having radii of 59.94 inches. The outer end and side wallq of
each bearing seat are approximately 1/2 inch thick and the
inner cylindrical wall i~ formed on a radius of 50.56 inch
(all radii measured from the center of the bolster pin
receptor 60). It i~ desirable that each bearing member 110,
110' be sized to leave a peripheral gap of about .44 inch
between it~ peripheral walls 136, 138, 140 and 142 and the
perimeter of the bearing seat 70. Accordingly, the bearing
bodies 112, 112' are cast to be approximately 15 inches
between side walls 140, 142 and 8 inches between arcuate walls
136, 138 with inner wall 136 formed on a radius of 51 inches
and the outer conical wall 138 formed from a top radiu~
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of 59 inches. The convex spherical undersurface 124 of each
bearing member and the concave spherical ~urface 74 of bearing
seat 70 are typically formed on radii of 15 inches.
For the one embodiment bearings 110 of FIGURES 6-8 the
second friction bodie~ 114a and 114b may typically comprise
di~cs of 4 inch diameter.
Variations and modifications may be made without
departing from the spirit and scope o-f the invention which is
defined in the following claims.
