Note: Descriptions are shown in the official language in which they were submitted.
1039S77
Attempts were first made to secure wear plates to the
roofs of pedestal jaws of railway truck side frames by two methodsJ
namely, flllet welding the wear plates to flat horizontal surfaces
along the edges of the wear plates and plug welding the plate to
the pedestal roof. Later, two additional techniques were tried.
First, a preformed plate, made from spring steel, was simply
snapped on the sides of the pedestal roof. Second, a "U" shaped
plate was attached by fillet welds between the upstanding legs of
the wear plate and the sides of the frame.
Wear plates attached to the horizontal surface of the
pedestal roof with fillet welds do not have an alternate mechanical
retaining system; i.e., lugs, bosses, to restrain the plate in the
event of weld failure, thus allowing loss of the plate when welds
fail. It appears probable that due to the limitations of geometric
configuration, the welds fail because an insufficient amount of
wèld has to be applied.
. The so called plug welded applications also include the design ;
having bosses on the pedestal roof with mating holes in the wear
plate. Because of pedestal jaw design as specified by the American
Association of Railroads, the design of the prior art wear plates
has been limited to a maximum plate thickness of 3/16 inch which
limits the strength of the attachment weld. A common specification
for such a spring steel plate is 0.109 inch thick AISI 1095 steel,
which has a short fatigue life. Anything other than an excellent
fit between pedestal roof and wear plate will most likely result
in the initiation of a fatigue crack in either the plate or
attachment welds.
The "U" plate design would be very difficult to fit to the
jaw of the side frame due to manufacturing tolerances inherent
in the casting process. The rocking action of the truck side
frame on the journal bearing adapter in combination with vertical
impact forces will most likely result in attachment weld failures.
~6~3~577
The plate will then be allowed to move relative to the pedestal
roof resulting in an ineffective application.
Accordin~ly, it is among the objects of the invention to
provide an improved wear plate design for the roof of the pedestal
jaw of a railway truck side frame.
In the Drawings. Fig. 1 is an elevation view of one of the
pedestal jaws of a truck side frame;
Fig. 2 is a plan view of the same construction;
Fig. 3 is a cross sectional view of a section taken along
line 3-3 of Fig. l; and,
Figs. 4 and 5 are elevation views showing other embodiments
of the invention.
In accordance with the present invention~ there is provided
a railway truck side frame having a ~ournal box housing and a pair
of pedestal jaws for engaging wheel axles on a railway car. The
jaws, two in number, have a roof and downstanding sidewalls. The
pedestal roof of the pedestal jaws has vertical, longitudinally
extending, peripheral lips on each side thereof between downstanding
sidewalls. A relatively flat wear plate is secured to the pedestal
roof with a weldment at the side surfaces of the plate. The weld-
ment extends substantially the length of the plate and, downwardly,
the weldment extends no lower than the vertical peripheral lips.
The above construction was tested and satisfactory performance
was exhibited at more than 200,000 cycles in the standard side
frame fatigue test. 100,000 cycles is accepted as being equivalent
to side frame life.
Referring to Figs. 1 and 2, a portion of the railway truck
side frame 2 is shown illustrating particularly one of the pedestal
jaw portions 4. The other portion not shown is located on the
opposite end of the side frame and is similar in construction.
As can be seen, the pedestal ~aw 4 contains a relatively horizontal
roof 6 and vertical sidewalls 8. The view of the side frame jaw
: , . .: .
~39S77
portion illustrates the frame as would be viewed rolling down a
railroad track. The relatively flat plate 10 is attached to the
roof by welding along the side surface of the plate for substantially
its entire length. As can be seen, the side portions of the Jaw
are open where the plate is attached. The front portion contains
vertical, longitudinally extending, peripheral lips 12 on each
side between the downstanding sidewalls. The weld 14 is protected
between the peripheral lip and the wear plate. If desired, the
peripheral lips can be of greater downward vertical extent so as
to completely envelop the wear plate. The weldment could extend
all the way down to the bottom of the peripheral lip and there
would be a smooth finish.
As shown in Fig. 4, the wear plate 24 is in a recessed
pocket where the lips 26 form the curved portion and the wear
plate 24 forms the flat portion of the AAR Standard pedestal ~aw
roof contour. This arrangement provides for additional articulation ~ -
between the truck side frame and the roller bearing adapter that
is absent when the fIat plate in Fig. 5 is used and provides the
same articulation now used on side frames without wear plates. ~ -
In Fig. 5, the lips 30 holding the wear plate 32 are tapered
at the ends 34 so that the weld attaching the wear plate to the
pedestal roof may be conveniently tapered at the ends so as to
minimize weld defects and stress raisers in the critical fillets
of the pedestal jaw 36. Were these tapers not present, the weld
would have to be ended abruptly resulting in a highly stressed
area where failures are known to have originated. The tapers may
be formed either linear or in the form of a curve, as shown.
Having thus described the invention in detail and with
sufficient particularity as to enable those skilled in the art to
practice it, what is desired to have protected by Letters Patent
is set forth in the following claims.
-3-
