Note: Descriptions are shown in the official language in which they were submitted.
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BACXGROUND OF TH~ INVENTTON
Field or the Invention
This invention relates to railroad car trucks wherein
wheelsets of the truck may move toward a position OL- align-
ment with the track over which the truck is traveling and
more particularly with a connecting devlce o~eratively
joinlng the wheelsets to regulate such movements.
Prior Art
~ odern railroad car trucks are commcnly referred to as
three-piece trucks which i~clude spaced side frames resil-
i~ntly su~porting therebetween a transversely positioned
bolster. The bolster contains a centerplate which in turn
supports a body of the railroad czr. The side frames have
downward projecting jaws in which axle ends of a rront and a
rear wheelset are rotatively journaled. Such trucks may
also be described as nonsteerable in that the bolster, side
frame and wheelsets are purposefully maintained in a squared
relatlonship.
Steerable trucks, on the other hand, are ones having
wheelsets which may yaw, for example. Such trucks are well
known and one ty~ical type is disclosed in U.S. ~atent
No. 3,789,770. As disclosed, this truck allows rotation of
each wheelset about its vertical axls so that the wheelset
may take an out-o -square position with respec. to a longi-
tudinal axis or the truck. The wheelsets are joined by
positive mechanical linkage whlch controls and malntains the
relationshi2 between the wheelsets. Additionally, this
linkage iS connectec to a body o_ the ~ailroad car so that
movement between the car body and the wheelsets is malntained
in a -ixed rela~ionshi?.
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Providing a flexible connection between the axle ends
~',, of the wheelset and tne side frame to allow yawing there-
between'is also well known and is disclosed in, for examDle,
, U.S. Patent No. 3,785,298. In this case, a resilient or
; elastomeric device interfaces between pedes~l jaws of a
side frame of the t-uck and axle ends of the wheelsets to
allow lim~ted movement therebetween which is -es,rained by
~' the elastomeric device.
U.S. Patent No. 3,528,37~ discloses a truck which is
one or the first to adapt steering principles to the modern
day three-piece truck. In this instance, a bolster has its
ends resiliently carried by side frames. Ends of the side
frames are adapted to allow the whee,lsets o~ the truck to
', yaw. Yawing in turn is regulated by parallel elastic bracing
members connecting aligned f~ont and rear axle ends and
diagonally positioned elastic bracing members connecting
opposite front and rear axle ends. A substantially ldentical
concept and structure is utilized in the BARBER-SC~FFEL
~igh Speed Radial Truck presently being offered for sale by
Standard Car Truck Company or Chicago, Illinois.
,~ A further arrangement to provide a truck with wheelsets
-' which can yaw so as to maintain an allgned rela~ionship with
; the track,on which the truck is traveling is disclosed by
U.S. Patent No. 4,003,316. As so disclosed, holding frames
which-carry the axle ends of the wheelsets are individually
connected to a bolster of the truck through a ball bearing
socket arransement enclosed in a pad. .~ny lateral movement
of the bolsier effects a rotational mov~ment of the holding
frame and thus the wheelsets.
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Most recent developments in steerable ~rucks are perha~s
disclosed in U.S. ~atent Nos. 4,067,261 znd 4,067,069. The
'261 ~atent discloses as its preferred embodiment a-t-uck
~uite similar to the comme-cially available truck noted
above. Particular emphasis is placed on the use of wheels
having highly profiled wheel treads to generate steering
forces. A pair of U-shaped suDframes carries the axle ends
o~ each wheelset and may be interconnected by a pair or
dia~onally positioned rods. These rods may, in turn, be
joined through a dampenlng device.
The '069 patent discloses 2 further steerzble railroad
car truck wherein resilient means of predetermined stiffness
interconnect .he axle ends carrying subfr~mes or the truck
at a centrally located point. Additionally, resilient means
interconnect the subframes with the side frames of the ~ruck
and the truck with a body of the car. The DR-l Steering
Assembly Truck commercially available from Dresser Industries,
Inc., of Depew, New Yor~, appears to embody many of the
teachings found in this patent.
SUMMARY OP T~E INVENTION
A railroad truck of this invention includes a pair of
spaced side frames each having a front and rear downward
projecting pedestal jaw. Resiliently car,ied by the pair of
side fr~mes at midpoints thereor are ends OL a t_ansversely
positioned bolster which in turn supDort there bove a body
of a railroad car.
Within the ront pedestal jaws o the side frames are
side Dortions of a U-sha~ed front stee-ins arm while a like
rear steerins arm has its side ~ortions ~ositioned within
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the rear jaws of the two side f_ames. Interfacing bet~een a
top surface of the side portions or each st2erins a~m and a
bottom surface of each pedestal jaw of the side frames is an
elastomeric device.
Each wheelset of the truck has its axle ends rotatively
journaled in bearings carried respectively by an adzpter
which in turn connects respectively with the side portion of
the steering arms. Thus, each wheelset and respective
steering arm is rormed into an integral unit.
The~elastomeric device allows each wheelset-ste~ring
arm unit to react to dynamic forces created during travel of
the truck and move to a new position in response to these
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oxces. These movements are multi-directional in na-ture and
occur-continuously.
These movements are in part regulated by a connecting
device which joins the two wheelset-steering arm units.
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- Protruding inwardly rrom a middle part of each steering arm
is a bracket. An inner end of each bracket is joined by the
connecting device which includes a linkage bar which connec.s
with-each bracket through two spherical bearing sets and a
; vertically disposed pin which passes through each bracket
and bearing set. This connecting device may be located
within a center ~avity specirically provided for such in tne
bolster of the truck. During movement of the wheelset-
steering arm unit, the connecting device remains independent
or the bolster in that the center cavity provides a clear
passage therethrough.
The truck of this invention has seve~al import~nt
advantages over both nonsteerable trucks and steerable
trucks presently known.
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Nonsteerable t-ucks inhibit yawing mov~ments of the
wheelsets. Known steerable trucks allow some movement which
until now was controlled by some resilient device or by
positive mechanical linkage connectina the rront and rear
S wheelsets.
I~ nonsteerable trucks, wear of the wheelsets is
advanced by sli?page between the wheelset and the track
which occurs as the truck traverses a curve. In known
; steerable trucks controlled solely by resilient devices,
increased wheelset movement is opposed by an ever increasing
restoring force.
On the other hand, this railroad car truck provides
means allowing each wheelset to react independently to
directional changes in the track on which the railroad car
is traveling. For example, when the truck encounters a
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left-hand curve in the track, the forwardmost or front
wheelset tends to rotate cou~terclockwise about its vertical
axis, i.e. yaw, while moments later the rear wheelset
likewise tends to rotate counterclockwise a~out its ver,ical
axis. However, the amount o rotatlon of each wheelset is
unequal so that the wheelsets move from a parallel to a
:
nonDarallel ?osition. This rotational tendency is created
by the conriguration of the outer sur-ace or the wheels
; interacting with the track. Because most such c~rves are
also ban~ed to allow higher speed travel, the wheelset also
; rotates about the longitudinal axis of the truck, i.e. roll.
These yawing and rolling movements of the wheelsets and
thus the wheelset-steering arm units are independent in
nature. The connecting device selec'ively accommoàates
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certain or these independent movements while at the same
time inhibitlng other movements. Additionally, the connecting
device, once 2ssembled, resists disassembly durins truck
operation.
Thus, this truck provides superior performance by
allowing multi-directional wheelset movemen,. Such movements
are regulated in part by the elastomeric devices and the
connecting device between the wheelset-steering arm units.
As a resul't, wheel wear is reduced and the dynamic stability
of the truc~ is improved during hlgh speed, heavy load and
rough road bed operation.
BRIEF DESCRIPTIO~ OF T~E DRAWINGS
FIG. 1 is a plzn view of a railroad car truck incorpo-
rating this invention.
FIG. 2 is a side elevational vlew in partlal section of
the truck of EIG. 1.
FIG. 3 is a detailed plan view of a portion or the
steering arm of the truck of FIG. 1 wherein the anms are
joined by a connecting device.
FIG. 4 is 2 cross-sectlonal view of the connectirg
devlce as gene~ally seen along the line 4-4 of FIG. 3.
DESCRIPTION OF THE PREFERRED EMBODIMENT
. . .
A railroad car truck is shown generally at 10 and
includes a front wheelset 12 and a rear wheelset 14. The
; Cront wneelset 12 has axle ends 16 journaled in rront wheel
bearings 18 while in a like manner the rear wheelset 14 has
2; axle ends Z0 journaled in rear wheel be~ring 22. It should
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be understood that the truck 10 is bi-directional, and the
terms "rront" and "rear" are used to more convenlently
describe the truck 10.
~itted over a top portion of each bearing 18, 22 is an
; adapter. ~ront adapters are designated 24 and rear adapters
26. The adapters 24, 26 each have an annular boss which
projects u~wardly from an upper side thereof. Supported on
the front adapters 24 is a front-steering arm 28 while thé
rear adapters 26 carry a rear steering arm 30~
Each ~L- the front and rear steering arms 28, 30 is
generally U-shaped and comprises a middle portion 32 connec-
ting with Z-shaped side portions 34. On an underside of
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each side portion 34 at its outer end 36 is an annular
recess which mates with the boss of the adapters 24, 26 so
as to join the steering arms 28, 30 with respective wheelsets
12, 14 into a front and a rear unit or combination 35, 37.
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On an upper surface of each steering arm side portion
outer end 36 is an upwardly facing recess 38 in which is
~- fitted zn elastomeric device 40. An u?per portion or each
2 elastomeric device 40 in turn fits withln a downwardlv
facing recess 42 formed in a roof portion o. 2 front and a
rear pedestal jaw 46, 48 of a pair OI s~aced lert, right
side frames 50, 52.
Each side frame 50, 52 has a centrally located window
25 ;4 to receive an end 56 or a transve-sely positioned bolster
:~, 58~ The ends 56 of the bolster 58 are resilien.ly s~2oor~ec
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,~, on sets of coil springs 60 in a known manner. FIG. 2 shows
one such resilient connection between the side frame 52 and
the bolster 58, and it should be understood that connection
between the bolster 58 on the side frame 50 is similar.
To dampen ver~ical oscillating related to coil spring
suspension, a pair of friction snubbing devices 62 interacts
,; between the bolster ends 56 and vertical wear plates 64
carried on s,paced sides 66 of each side frame window 54.
The bolster 58 includes an integrally formed cente_
plate 68 which connects with a body or the railroad car ~not
shown) in a known manner. Below the centerplate 68 in the
bolster 58 is a cavity 70 providing a clear horizontal
passage through a center of the bolster 58. One preferred
~bodiment of such a bolster center cavity 70 is set rorth-
in U.S. Patent No. 4,114,540. The truck l0 further includes
f-ont and rear braking means 72, 74 which is discussed in
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greater detail subsequently.
On the middle part 32 of the front and rear steering
arms 28, 30 is a bracket 76 which forms part of a connecting
means 78 between the front and rear wheelset-steering arm
units 35, 37. The brackets 76 project into the bolster
center cavity 70 in an opposing manner as is best understood
by viewing FIGS. l and 3.
Ends 80 of each ~racket 76 lie adjacent to and on
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` 25 ' opposlte sides of a ver.ical plane passing through a longi-
tudinal axis Ld of the,truck 10. Each bracXet end 80 is
bifurcated into an upper p ong 82 and a lower ?rong 84.
Sets of vertically aligned apertures 86, 88 2-e .ormed in
', each upper and lower prong ?air 82, 84 of each Dracket end
, ~0 80. 7~rnen the ~ront and rear wheelset-steering a~m uni~s
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35, 37 are in a sauared relationship with res?ect to the
side frzmes 50, 52 and the bols~er 58, the aperture pairs
82, 84 align with a vertical plane which passes throush a
lateral axis La of the truck 10.
Pressed into each o~ the apertures 86, 88 is a bushing
90. Horizontally disposed between the upper and lower
prongs 82, 8a or each bracket end 80 is an elonga.ed linkage
bar 92. Apertures 94, 96 are formed adjacent to ends o~ the
bar 92 and are so positioned to align with the apertures 86,
88 in the upper and lower prongs 82, 84 respectively.
- In each bar aperture 94, 96 is a spherical bearing set
; 98 comprising an inner element 100 and an outer element 102.
The outer element 102 has a circular outer wall 104 to rit
snugly within the bar apertures 94, 96 and a concave spherical
inner wall 106. The inner wall 106 engages in a complementary
manner with a convex spherical-shaped outer wall 108 of th_
inner be2ring element 100. The inner bezring element 100
rurther includes an inner circular passage 110.
Disposed through each bushing 90 and through the inner
passage 110 of each bearing set 98 is a pin 112. ~ach pin
112 has an enlarged head 114 to limit downward movement and
; a lower cotter pin aperture 116. A cotter pin 118 may be
conveniently disposed through lower pin aperture 114 ar.er-
assembly to limit upward movement or that pin 112.
Dynamic and static foraes occur~ing during 03era.ion o'
the truck 10 results in the wheelset-steering arm units 35,
37 tending to move rotationally and linearly in all three
directions 3ecause these rorces vary in cirection and
magnitude, the actual movemen's or the wheelset-s~eering ar~
units 35, 37 are lzrgely un?r3dlctable. Yowever, the s-ructu_e
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of ~he truck 10 is such that these multi-directional move-
ments may be accommodated between sets limited and selec-
tively regulated to the degree~that certain movements are
predictable.
As may be more easily understood by viewing FIG. 4,
either wheelset-steering arm combination 3~, 37 may move
vertically, pitch or roll without such movements being
impeded by the connecting device 78. Such mov~ments of each
unit 35, 37 may be out-of-phase, i.e. in the same direction,
or in-phase, i.e. in the opposite direction. Regardless,
each unit 35, 37 is not restrained by the other 'hrough the
connecting device 78. Thus, the wheelset 12, 14 of either
unit 35, 37 may move to a more aligned position with the
track over which the wheelset 12, 14 is in contact to
accommodate for variation in track direction and rail height.
~o~ever, certain horizontal and yawing movements of the
wheelset-steering arm unlts 35, 37 are restrained by the
connectins device 78. For example, all in-phase horizontal
movements or the units 35, 37 which align wi~h the lateral
axis La of the truck 10 are inhibited by the connecting
device 78. Likewise, in-phase yawing movements of the units
35, 37 are inhibited by the connecting device 78. Yawing o~
the wheelset-steering arm units 35, 37 occurs when the ~ruck
10 proceeds about a curved section of track. Such yawi~g of
the units 35, 37 is maintained in an exact out-o--pha~e
relationship by the connecting ~evice 78.
Inhibiting in-phase yawing movement of tne units 35, 37
is particularly im?ortant to maintain proper dynamic stabilitv
of the truc~ 10. ~or example, during travel, ~e side frame
50, 52 tends to lozenge, i.e. the side L-ames 5~, 52 remain
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parallel but move ~o a longitudinzlly orfset position, under
dynamically induced forces. ~or lozenging to occur, one
wheelset-steering arm unit, for example the front unit 35,
must move in one di-ection while the rear wheelset-steering
i arm unit 37 must move in the opoosite direction or move in-
phase. Lozenging reduces the critical speed of the ,ruc~ 10
wherein the wheelsets 12, 14 tend to hunt, i.e. dynamically
induced oscillating about a vertical axis of each wheelset.
The connecting device 78 prohi~its such in-phase movement.
Thus, the side frames 50, 52 are inhlbited from lozenging
which in turn maintains the critical speed above that which
the truck 10 and associated rzilroad car body is expected to
travel.
On the other hand, in-phase or out-o,-phase horizontal
L5 movements of the units 35, 37 which are aligned with the
longitudinal axis Ld of the truck 10 are not res~rained by
the connectlng device 78. Such movements occur when the
front and rear braking means 72, 74 are activated.
The braking means 72, 74 is conventional in nature and
~a includes a brake beam 120 with brake shoes 122 supported
from outer ends of such for engagement with the front and
rear wheelsets 12, 14. Each brake beam 120 pivotally connects
with a lower end 124 of a brake lever 126. A tie rod 128
pivotally joins a center portion 130 or each lever 126. An
upper end 132 o~ one brake lever 126 may be pivotally joined
to a body of the railroad car (not shown) while the upper
end 132 of the other ~rake lever 126 is operatively connected
to a ~ower device (not shown) by a connec_ing rod 134.
Move.~ent of the connecting rod 134 in the direction
O opposite the arrow D in ~IG. 1 fo-ces the brake shoes 122
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against the wheelsets 12, 14 to move the units 35, 37
.
slightly apart. This slight in-phase movement of the units
35, 37 is not inhibited by the connecting device 78.
Proper mechanical operation of the connecting device 78
is enhanced by placing the device 78 within the protective
environment provided by the bolster center cavity 70.
Furthe_, by locating the spherical bearing sets 98- of the
linkage bar 92 between the upper and lower prongs 82, 84 of
each bracke~ end 80, the bearing sets 78 are shielded r^rom
foreign matter associated with railroad car travel.
Likewise, the connecting device 78 may be readily
assembled or disassembled to allow periodic maintenance.
~owever, because the connecting device 78 allows each
wheelset-steering arm unit 35, 37 to move in a number of
directions without regulation of those movements, the
- connecting devlce 7~ is not unduly subject to the dynamic
force causing those movements. Thus, the connecting device
78 may remain reasonably maintenance free.
A further adva~tage provided by the connecting device
78 is that it is reasonably fail safe frcm disassembly. For
such disass~mbly to occur, one of the pins 112 must become
....
disassociated from the linkage bar 9~. Downward movement of
each pin 112 is limlted by the pin head 114. Upward move-
ment of the pin 112 can only occur upon fallure of the
~S cotter pin 118 and applica.ion of a sufficient force over an
opposite gravitational force to cause a lower end of the pi~
112 to move a~ove the linkage bar 92. The liXelihood of -
both such events occurrinq is slight indeed.
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While varLous minor modifications may be suggested by
those versed in the ar., it should be understood that I wish
to embody within the scope of the p2tent warranted hereon
; all such modifications as reasonably and prooerly come
wtihln the scope of my contribution to ~e art.
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