Note: Descriptions are shown in the official language in which they were submitted.
In inter-city travel by rail cars where large radius curves are
involved, it is desirable to provide small amounts of self steering in the truckwithout adversely affecting the stability of the truck. This is especially desi-rable when the car is travelling at high speeds. At the same time, such sel-f
steering should be provided without requiring major design changes in the truck
thereby making such self steering available for retrofitting on existing trucks.A railway car presently being used extensively utilizes a truck with a
rigid frame along with equalizer beams. The rigid frame comprises an "H" shaped
frame. This type of frame maintains the truck in tram or keeps the axles para-
llel or squared with respect to each other during travel. The rigid frame is
~ generally used with equalizer means associated with journal boxes slidably moun-
- ted within the ends of the side frames. The equalizer means include equalizer
beams which extend on both sides of the truck and mounted on top of the front and
rear journal boxes.
The journal boxes are disposed to slide up and down within the ends of
t.he side frames of the truck. The loads app:Lied to the wheels of the car are
transmitted through the axles and journal boxes to the equalizer beams.
- The equalizer beams bring the load over equalizer springs. Equalizer
beams are used so that, during travel, if one wheel is lifted, the load will notchange much. The equalizer beams and springs equalize the vertical loads on the
wheels.
An arrangement having a rigid frame and equalizer means, as described
above, makes it extremely difficult to provide a truck with self steering. At
the same time, such self steering is highly desirable because it greatly enhances
the ride comfort of passengers and it also reduces track wheel wear and lateral
track force. The advantages of steerable trucks are well known and are part of
- the prior art.
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It is an object of this invention to provide an improved
truck having high stability with a limited amount of self steering.
It is a further object of this invention to provide means
for permitting a limited amount of self steering in a relatively
rigid truck without modifying the basic design or parts in the
truck~
In accordance with the present invention, there is pro-
vided in combination with a rigid frame in a truck with a pair of
side frames and wheels connected to axles to contact rails, jour-
nal boxes including said axles, equalizer beams mounted to the
~: tops of sa.id journal boxes, a pair of pedestal liners provided in
each of the ends of said side frames on opposite sides of each of
said journal boxes to permit said journal boxes to slide up and
down therein, each of said pedestal liners including a pair of
mutually parallel "C" shaped posts one of which is fixed to a side
frame and one of which is smaller than the other, a pair of flex-
ible members connected be.tween the legs of the posts to permit
~` limited longitudinal movement of the journal box associated there-
with, said posts being responsive to creep forces developed in
. 20 said wheels to cause angular movement of one post with respect to
the other, the angular movement being limited by the space bet-
ween the pGStS and a third flexible member connected between said
side frame and the top of each journal box to permit radial move-
ment of said journal box and the axle contained therein.
The invention will now be described in greater detail
with reference to the accompanying drawings r in which:
Figure 1 is a side view of a steerable truck, in accor-
dance with the present invention;
Figure 2 is an enlarged view of a portion of Figure 1illustrating in greater detail one end of the truck of Fiyure l;
and
Figure 3 is a cross-sectional view, taken along lines
3-3 of Figure 2.
Referring to Figure 1, a rail truck 10 is disposed to
~ carry a rail ~ar body 12, Except for the features relating to
.~ the elements provided for self steering, the truck 10 may be con-
ventional. Only one side of the truck 10 is illustrated in Figure
1, it being understood that the opposite side of the truck in-
cludes substantially similar parts operating in substantially
the same manners.
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The truck 10 comprises a pair of longitudinally extending side frames,
only one of which side frame 14 is illustrated. The main Erame of the truck may
comprise an "H" shaped rigid frame of which a central portion (not illustrated)
connects the two side frames. The relatively rigid frame maintains the truck in
tram during operation.
The opposite ends of the side frames are shaped to provide open areas
16 and 18 for receiving the journal boxes 20 and 22, respectively with retainingstrips 17 and 19 being secured below the open areas of the ends of the frame.
The journal boxes 20 and 22 are disposed to slide up and down within the ends ofthe side frames in the areas 16 and 18 during operation.
A pair of equalizer beams, of which only one beam 24 is illustrated,
~ extend longitudinally in the same direction and generally parallel to the side
; frames. The equalizer beams are sui~ably mounted to the tops of the front and
roar journal boxes. The beam 24 has its ends mounted to the journal boxes 20
and 22 which include axles 21 and 23, respectively.
A pair of equalizer springs 26 and 28 are connected between the equali-
zer beam 24 and side frame 1~. The beam 2~ carries the load from the journal
boxes 20 and 22 to the equalizer springs 26 and 28. The purpose of the equalizerbeam and springs is to equalize the vertical loads on wheels 30 and 32, connected
to axles 21 and 23, respectively, so that if one of the whoels 30 or 32 is lifted
with respect to the other, the vertical loads on the wheels will not change sub-stantially.
A bolster 34 is secured to the truck frame and pivots about the center
of the truck in a conventional manner. The bolster is tied to the car body 12 byappropriate means including an anchor member 36 and anchor rod 38. A secondary
spring ~0 of conventional design is connected between the car body 12 and bolster
34. ~igures 2 and 3 illustrate the features of the present invention which may
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be incorporated in a truck, such as illustrated in Figure 1.
~ eferring to Figures 2 and 3, the operation of the journal box 22 is
the same as the journal box 20 (Figure 1~ and involve the same type of parts.
Consequently, it will be assumed that all the journal boxes in the truck 10
operate in substantially the same manner and therefore only the operation of the
; journal box 22 will be described. Specific details associated with the journal
boxes, such as bearings, primary suspension units and other elements are not
illustrated or described because they are conventional and not necessary to an
understanding of the present invention.
The journal box 22 is disposed to slide up and down on pedestal liners
42 and 44. The present invention is directed to ~he ~eatures which permit the
journal boxes to slide up and down as in the prior art, but at the same time per-
mit the axles 21 and 23 within the journal boxes to move radially limited amounts
as the car goes around curves in the track and the wheels are subjected to wheel
rail creep forces.
It is known that when a truck goes around curves that creep forces are
developediat the wheel rail interface which tend to force the axles to be moved
radially. However, when the frame of the truck is rigid and equalizer beams are
used, as described above, the axles are not free to move within the journal boxes
which can only slide up and down in pedestal liners in the ends of the side
frames. As is known, when the axles are not free to rotate radially to some
extent during curves, wheel and rail wear develop and passenger riding comfort is
decreased.
Each of the pedestal liners 42 and 44 comprises vertically disposed
posts 46 and 48 shown in Figure 3. The pos~s 46 and 48 are "C" shaped with the
post 48 being smaller ~han tha post 46. The post 48 is disposed partly within
the post 46, and is spaced generally parallel thereto. The post 48 is fixed to
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the end portion 51 of the side frame 14 by means of a bolt or other means. In
some cases, the post 48 may be a cap member secured to the frame.
Flexible members 50 and 52 are sandwiched between the vertical ends or
legs of the "C" of the posts 46 and 48. The flexible members 46 and 48 are rel-
atively soft longitudinally so that, if the creep forces are developed during
curves, the post 46 will move with resyect to the post 48 and consequently the
side frame 14 permit the axles 21 and 23 to be free to move longitudinally.
In addition to permitting the axles 21 and 23 to be moved longitudin-
ally~ a third flexible member 54~ shown in Figure 2, is used to permit the axles
to be moved radially. The flexible member 54 is sandwiched between plates or
caps 56 and 58. The plate 56 is secured to a connecting member 60 which is con-
nected to the end of the equalizer beam 24. The plate 58 is secured to the top
of the journal box 22.
The flexible members 50~ 52 and 54 allow the post 46 to move angularly
with respect to the fixed post 48. This movement permits the axle 23 to take a
radial position due to creep forces.
While lt is desirable`to permit a certain amount of movement of the
axles when the creep forces are high~ the flexible members should not be so soft
to adversely affect the stability of the ~ruck. The flexible members may com-
prise rubber designed to have pPedetermined spring rates dependent upon the over-
all design of the truck involved.
The vertical post 48 is spaced from the post 46 to permit the post 46
to be moved angularly with respect to the fixed post 48. The relatively small
space between the posts 46 and 48 limits the amount of angular movement there
between because the angular movement will stop when the posts 46 and 48 contact
each other. This arrangement therefore limits the amount of radial movement of
the axles regardless of the magnitude of the creep forces. Thus ~he present
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invention maintains the stability of the truck between predetermined maximum
limits.
The present invention has made possible radial movements of the axles
in a truck to permit a limited amount of self steering without substantially
affecting the stability of the truck. This is highly advantageous in a rail car
~ravelling at relatively high speeds around curves in inter-city travel.
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