BRAKING SYSTEM FOR RAILROAD TRUCK

SYSTEME DE FREINAGE SUR BOGIE DE VEHICULE FERROVIAIRE

English Abstract

BRAKING SYSTEM FOR RAILROAD TRUCK
ABSTRACT OF THE DISCLOSURE
A braking system for a railroad car truck having
its front and rear wheelsets so connected to permit each
wheelsets to yaw as the truck proceeds about curved trackage
includes a front and rear brake beam and brake shoes
attached thereto for engagement with the front and rear
wheelsets. Each brake beam is pivotally connected to a
front and rear brake lever, respectively, which are in
turn pivotally connected to a front and rear swingable
arm of the truck. During yawing or horizontal rotational
movements of the wheelsets and the swingable arms in
which the wheelsets are journaled, the brake beams and
truck levers move complementary to each other so that when
a braking force is applied to the truck levers, the
rotational position of the wheelsets is unaffected by
the braking force as the brake shoes engage the wheelsets.
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Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of braking for use with a truck of
a railroad car having swingable first and second wheelsets
and first and second swingable arms in which said wheel-
sets are rotatably mounted, said method comprising the
steps of:
1) applying a linear braking force to a middle
portion of a floating brake lever positioned transversely
to a direction of said linear force,
2) dividing said linear force into a first
and second force component and transferring said first
and second force components to first and second elongated
connecting rods having one end connected respectively to
ends of said floating brake lever,
3) positioning said first and second connecting
rods substantially parallel to said direction of said linear
braking force,
4) transferring said first and second force
components to a first and second truck lever having ends
attached to opposite ends of said connecting rods respec-
tively with said levers positioned substantially perpen-
dicular to said connecting rods,
5) supporting an opposite end of said first
truck lever from a pivot permanently mounted to said first
swingable arm,
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6) supporting a middle portion of said second
truck lever from a pivot permanently mounted to said
second swingable arm,
7) connecting a first braking device to a
middle portion of said first truck lever and a second
braking device to an opposite end of said second truck
lever,
8) moving said ends of said first and second
truck levers in said direction of said linear braking
force with said first and second force components,
9) moving said first braking device in said
direction of said linear braking force and said second
braking device in an opposite direction, and
10) engaging said first and second wheelsets
with said first and second braking devices,
wherein a horizontal rotation of said first
or said second swingable arm causes a like rotation of
said first or second braking device and is unaffected by
activation of said braking force.
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2. A method of braking a truck of a railroad car
having a first and second wheelset rotatably carried in a
first and second swingable arm respectively, said swingable
arms carried in side frames of said truck so as to permit
limited horizontal rotational movements between said side
frames, said method comprising the steps of:
1) positioning a first and a second truck
lever in an upright orientation,
2) supporting a bottom end of said first truck
lever in a pivot fixed to said first swingable arm,
3) supporting a middle portion of said second
truck lever in a pivot fixed to said second swingable arm,
4) connecting a first braking device to a
middle portion of said first lever arm,
5) connecting a second braking device to a
bottom end of said second truck lever,
6) translating horizontal rotational movements
of said first or second wheelset to said first or second
braking device through said swingable arms and said truck
levers attached thereto,
7) applying a linear braking force having a
first direction proximately perpendicular to said levers
to top ends of said truck levers to cause a rotation
thereof,
8) converting said rotation of said first
truck lever to a linear force having a direction proximating
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said first direction to move said first braking device in
said first direction,
9) converting said rotation of said second
truck lever to a linear force having a direction opposite
said first direction to move said second braking device
in an opposite direction, and
10) engaging said first and said second wheel-
sets with said first and second braking devices to cause
a decrease in rotational velocity of said wheelsets,
wherein said braking force may be applied
without unduly changing a horizontal position of said
wheelsets with respect to said side frames.
3. A braking system for a railroad car truck
having a transversely positioned bolster supported at its
ends in a right side frame and left side frame and a front
and a rear wheelset rotatably mounted in a front swingable
arm and a rear swingable arm, respectively, said arms
being connected to said side frames to allow relative
movement of said swingable arms with respect to said side
frames, said system comprising,
means for supplying a braking force, said
means connected to said braking system,
means for dividing said braking force into
a first and second force component,
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first and second connecting means for trans-
ferring said force components respectively,
first and second lever means connected to said
first and second connecting means for converting said force
components to a first and second rotatable moment,
a first pivot means provided on said first
swingable arm and connected to an opposite end of said
first truck lever and a second pivot means provided on
said second swingable arm and connected to a middle portion
of said second truck lever, and
first braking means and second braking means
engageable with said first wheelset and said second wheelset,
respectively, for applying a braking force thereto, said
first braking means pivotally connected intermediate the
ends of said first lever means and said second braking
means pivotally connected at an opposing end of said second
lever means,
` whereby said first braking means and said
second braking means move horizontally with respect to
horizontal movements of said swingable arms and remain
aligned with said wheelsets upon an application of said
braking force.
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4. A braking system for a railroad car truck
comprising,
a truck body,
a left and right side frame carried by said
body,
a front swingable arm and a rear swingable
arm resiliently engaged with said side frames to allow
limited horizontal rotational movements of said swingable
arms with respect to said side frames,
a front wheelset and a rear wheelset each having
axle ends rotatively carried in ends of said front and rear
swingable arms respectively,
an upwardly oriented front truck lever having
a lower end pivotally attached in a bracket intermediate
ends of said front swingable arm,
an upwardly oriented rear truck lever pivotally
mounted intermediate its ends to a bracket provided on a
center part of said rear swingable arm,
a front braking device including a front brake
beam and a right brake shoe and a left brake shoe carried
at ends of said beam, said beam pivotally connected to a
center portion of said front truck lever with said shoes
aligned to engage with said front wheelset,
a rear braking device including a rear brake
beam and a right brake shoe and a left brake shoe carried
at ends of said beam, said beam pivotally connected to a
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bottom of said rear brake lever with said shoes aligned to
engage with said rear wheelset,
a front connecting rod and a rear connecting
rod positioned substantially parallel to said front rod
with said rods positioned substantially perpendicular to
said truck levers, said rods each having one end thereof
connected to a top end of said front and rear truck levers
respectively, and
a floating brake lever positioned transversely
to said connecting rods and having ends connected to
opposite ends of each said connecting rod respectively,
wherein a horizontal position of said front
swingable arm or rear swingable arm with respect to said
side frame remains unaffected by an application of a
braking force to said floating brake lever to activate
said system.
5. A braking system as defined by Claim 4 and
further characterized by,
said front truck lever having a horizontal end
segment joining with said front swingable arm bracket to
form a vertical pivot,
said middle portion of said front truck lever
being at an elevation below said vertical pivot with said
front brake beam attached to said middle portion adjacent
to a brite of said truck lever to align proximately horizon-
tally with said rear brake beam.
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6. A method of braking for use particularly with
railroad car trucks having swingable wheelset means,
comprising the steps of:
1) supplying a braking force having a first
linear direction,
2) dividing said braking force into a first
force component and a second force component each having a
direction proximating said braking force direction,
3) converting said first force component and
said second force component into a first rotational moment
and a second rotational moment by applying said force
components to an end of a first and a second truck lever
respectively,
4) rotating with said first rotational moment
said first truck lever about a pivot formed between an op-
posite end of said first truck lever and a bracket carried
by a first swingable arm of said swingable wheelset means,
5) rotating with said second rotational moment
said second truck lever about a pivot formed at a point
located between said end and an opposite end of said
second truck lever and a bracket carried by a second swing-
able arm of said swingable wheelset means,
6) converting respectively said rotation of said
first truck lever and said second truck lever into a third
linear force and a fourth linear force having proximately
equal magnitudes but opposite directions, and
7) applying said third linear force to a first
bracking device carried by said first truck lever at a point
located between said end and said opposite end and said
fourth linear force to a second braking device carried by
said second truck lever at said opposite end to engage said
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wheelsets and cause a decrease in rotational velocity of
such.
7. A method of braking as defined by Claim 6 and
further characterized by,
said first force component and said second force
component having proximately equal magnitudes, and
said first rotational moment and said second
rotational moment having proximately a same rotational
direction.
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8. A braking system for a railroad truck having
a truck body and wheelsets mounted for turning movement in
opposite directions as the truck traverses curved trackage,
said braking system including,
dividing means for dividing a braking force
supplied to said braking system into two forces,
converting means for converting each of said
two forces into individual rotatable moments of the same
direction,
reconverting means for reconverting said
rotational moments into equal linear forces of opposite
directions, and
friction applying means engageable with res-
pective one of said front wheelsets and said rear wheelsets
for braking said wheelsets.
9. The braking system as defined in Claim 8
including,
transfer means for connecting said dividing
means and said converting means.
10. The braking system as defined in Claim 8
wherein said converting means includes,
converting lever means pivotally connected to-
said truck frame, and
said reconverting means is connected to said
lever means to provide said equal and oppositely directed
forces.

11. The braking system as defined in Claim 9 wherein
said dividing means comprises,
a force supply lever pivotally connected inter-
mediate its ends to said truck body.
12. The braking system as defined in Claim 10 wherein
said converting lever means includes,
a first converting lever pivotally connected
intermediate its ends to said truck body, and
a second converting lever pivotally connected
at one end to said truck body.
13. The braking system as defined in Claim 11 wherein
said reconverting means includes,
a first reconverting lever connected to one end
of said first converting lever and said second reconverting
lever is connected intermediate the ends of said second
converting lever.
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14. A brake rigging for a railroad car truck
including a front and a rear wheelset having axle ends
rotatively carried by a front and a rear U-shaped swing-
able arm, respectively, said swingable arms having side
portions being joined to ends of a pair of spaced side
frames such that said front wheelset with said front
swingable arm and said rear wheelset with said rear
swingable arm may rotate about a vertical axis of said
respective wheelset, and a transversely positioned
bolster having ends respectively carried in a pocket formed
in a middle portion of each said side frame, said brake
rigging further comprising,
a front truck lever carried in a pivot connection
formed in part by said front swingable arm with a center of
said pivot connection proximately aligning with a longitudinal
axis of said front swingable arm,
a front braking device carried by said front truck
lever a first distance from said pivot connection, said de-
vice including a pair of spaced brake shoes engageable with
wheels of said front wheelset,
front operative means connected to said front truck
lever at a distance greater from said pivot connection than
said first distance, said means prepared to selectively rotate
said front truck lever to engage said front brake shoes with
said front wheels,
a rear truck lever carried in a pivot connection
formed in part by said rear swingable arm with a center of
said pivot connection proximately aligned with a longitudinal
axis of said rear swingable arm,
a rear braking device carried by said rear truck
lever on one side of said pivot connection, said device in-
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cluding a pair of spaced brake shoes engageable with
wheels of said rear wheelset, and
rear operative means connected to said rear
brake lever on a side opposite said pivot connection,
said means prepared to selectively rotate said rear truck
lever to engage said rear brake shoes with said rear
wheels.
15. A brake rigging as defined by Claim 14 and
further characterized by,
said front and said rear braking devices being
positioned below said front and said rear swingable arms,
and
said front and said rear operative means being
positioned above said front and said rear swingable arms.
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Description

Case 5574
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BACKGROUND OF l~IE INVENlrION
~ .
Field of Invention
This invention relates to railroad car truck
braking systems and more particularly to a braking system
for a railroad truck having conjointly rotatable wheelsets.
Prior Art
Heretofore, one popular braking system for a
railroad car includes an elongated front and rear brake
beam having brake shoes mounted adjacent to each end
and positioned to engage with a front and rear wheelset
of the car truck. Ends of the brake beam are slidably
carried in angularly disposed guides formed in a right
and a left side frame of the car truck to allow linear
movement of the beam when a braking force is applied.
Another railroad truck braking system associated
with railroad car trucks includes a pair of elongatad
brake beams with similar brake shoes positioned on the
opposite ends of each beam. To support each brake beam,
one end of a pivot arm is attached to each brake shoe
while an opposite end of the pivot arm is pivotally carried ~
in a bracket located above the shoe and formed as part of -
each truck side frame. A center of th~ brake beam is
slidably carried by a support spring to allow linear move-
ment of the beam and thus engagement of the shoes with the
truck wheelsets upon an application of a braking force to
each beam.
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SUMMARY OF THE INVENTION
A braking system of this invention for use with
railroad car trucks having swingable wheelsets includes
a front and a rear brake beam having attached at outer
ends thereof brake shoes positioned to aIign and engage
with a front and a rear wheelset of the car truck upon
application of a braking force.
Each brake beam is pivotally connected respectively
to a front and rear truck lever with the front brake beam
attached to a bottom end of the front truck lever. The
front truck lever is pivotally mounted intermediate its
ends on a front swingable arm of the truck. The rear truck
lever has a bottom end pivotally carried by a like bracket
on a rear swingable arm of the truck with the rear brake
beam attached to a center portion of the rear truck lever.
To a top end of each truck lever is attached one end of
front and rear connecting rods with opposite ends of each
rod in turn connected to a transversely positioned floating
lever.
By applying a braking force intermediate the ends ~-~
2~ of the floating lever, the braking force is distributed
by the floating lever into force components and transferred
by ths front and rear connecting rods to cause a rotation
of the front and rear truck lever, This rotation in turn
results in movement of the brake beamsso that the attached
brake shoes engage the respectl~e front and rear wheelsets,

4~4z3 ~; a s e ~ ~ J4
The railroad bra~ing system of this invention has
several important advantages over known railroad braking
systems.
Firstly, in order that the car truck function
properly, each wheelset must be mounted for rotation hori-
zontally about its vertical axis, as for example, when the
railroad car travels along a curve in the track. When
such rotation of the wheelsets occurs, the wheelset assumes
a nonperpendicular or out-of-square position with respect
to the longitudinal axis of the truck.
Activation of the braking system as constructed
heretofore under conditions when the wheelset is in an
out-of-square condition exerts forces tending to move
and realign the wheelset to a squared condition.
This is undesirable because the realigning forces
cause wheelset wear particularly when traversing curved
track.
The braking system of this invention is constructed
so that the braking forces do not affect the position of
the wheelsets upo~ activation thereby to reduce wheelset
wear.
Another feature of the present brake system is that
the wheelsets are not unduly longitudinally displaced with -
respect to the side frame upon brake activation. Such
displacement does not occur because the steering arm carries
both the brake beam and the wheelset. As a result, slack

Case ~/4
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adjusters provided to compensate for brake shoe wear may
unction properly,
BRIEF DESCRIPTION OF THE DE~AWINGS
FIG. 1 is a plan view of a railroad truck incor-
porating the braking system of the present in~ention.
FIG. 2 is a side elevation~l view of the truc~
of FIG. 1. -:
FIG. 3 is a schematic diagram of the braking
system.
FIG. 4 is a fragmentary elevational view taken ~
generally along the lines 4-4 of FIG. 1. ~ -
DESCRIPTION OF THE PREFERRED EMBODIMENT
The braking system of the present invention may
be more easily understood if it is considered as a system
of forces as illustrated in FIG. 3 and to which reference
is made.
A linear braking force F is applied in a direction
as indicated by the arrow and is divided into two fbrce
components F (front) and F (rear) having the same direction
as the force F. The forces F (front) and F (rear) are
con~arted into rotational moments M (front) and M (rear)
2~ which are then reconverted into opposite and equal linear
forces F (front)' and F (rear)'.
This force system may be accomplished by a number
of mechanical arrangements to create a braking system
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r Case 5574
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embodying the present invention. In the embodiment as
shown in FIGS. 1 and 2, a brake system S is applied to
a car truck 10 generally including a front wheelset 12 and
a rear wheelset 14. The front wheelset 12 has axle
ends 16 rot3~ably carried in 8 front generally U-shaped
swingable arm 18. In a like manner, the rear wheelset 14
has axle ends 20 rotatably carried in an opposite facing
generally U-shaped swingable arm 22.
The tr~ck 10 further includes a pair of side
frames 24, 26 and a transversely positioned bolster 28.
The swingable arms 18, 22 are carried in the side frames
24, 26 in such a manner that each wheelset 12 and 14 and
attached swingable arm 18 and 22 may rotate horizontally
about its respective vertical axis 50 that a longitudinal
axis of the wheelset, as an example the wheelset 12, takes
an out-of-square position with respect to the longitudinal
axis of the truck.
Assuming that the truck 10 is traveling in a
direction designated by the arrow D in FIG. 1 and traverses
a track section curving to the left relative to the direc-
tion of movement, the front wheelset 12 and front steering
srm 18 rotate counterclockwise while the rear wheelset 14
and the rear steering arm 22 rotate clockwise about the

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respective vertical axis of each wheelset 12 and 14. In part, thic
opposite rotation occurs because the truck 10 is attached
to the car body by a center plate 30 on the bolster 28 ~ :
which is located an equidistance between the front and rear ~-
wheelsets 12 and 14 and aligned with the longitudinal axis ~.
of the truc~ 10.
To a center part 32 of the front swingable arm 16
and to a center part 34 of the-rear swingable arm 22 are
provided a front horizontal bracket 36 and a rear inclined
bracket 38 in which there is pivotally carried a front ::~
truck lever 40 and a rear truck lever 42, respectively. -~
The front truck lever 40 may be of a U-shaped configuration :~
with a horizontal end segment 44 connected to the front
bracket.36 of the front swingable arm 18.
lS The rear truc~ lever 42 may have an elongated config-
uration to be upwardly orientated with a middle section 46
of the rear truck lever 42 which is pivotally carried by the ~ -
rear bracket 38 o~ the rear swingable arm 22. A top end 48
and 50 of each of the truck levers 40 and 42 is connected
to.an end of a front and rear connecting rod 52 and 54,
respectively, which are positioned substantially parallel
to the longitudinal axis of the truck 10 and thus perpendicular
to the levers 40 and 42. The front and rear connecting rods
52 and 54 are so dimensioned that opposite ends of each
rod 52 and 54 are aligned and are pivotally joined to a
transversely positioned floating lever 56 by means of pivot .
. . .
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pins 51 and 53. Means such as an air cylinder [not shown]
for applying the linear braking force F is pivotally
attached by means o pin 55 to a middle portion of the
lever 56 intermediate the connecting pins 51 and 53.
A front brake rigging includes a front brake ::
beam 58 pivotally connected adjacen~ to a middle portion 60
of the U-shaped front truck lever 40 with left and right
front brake shoes 62 and 64 carried at each end of the
front brake beam 58 aligned to engage the front wheelset 12.
A rear brake rigging includes a rear brake beam 66 pivotally
attached to a lower end 68 of the rear truck lever 42 with
left and right rear brake shoes 70 and 72 carried at each
end of the brake beam 64 aligned to engage the rear wheel-
set 14. Guide brackets ~not shown] ~ay be formed as part
of the side frame 24, 26 to aid in positioning ends of the
braka beams 58, 66 to ensure proper engagement.
. As was noted earlier, the forces F (front)' and ~: :
F (rear)' applied to the front and rear brake beams 58 and 66
are equal so as to promote uniform wear of the brake shoes
62, 64 and 70, 72 and provide like braking of each wheelset
12 and 14.
These forces F (front)' and F (rear)' are equal
because the distances between the ends 48 and 50, the middle
portions 60 and 46 and the opposite ends 44 and 68 of each
truck lever 40 and 42 have been selec~ed with respect to
the magnitude of the force applied, i.e. F (front) and
F (rear). In the exemplary embodiment, if the distance "a"
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~ 10~4423 Case 5574
is equal to the distance "c" while the distance "b" is equal
to the distance "d" and twice the ~istance "a" and "c", the
ratio of force F (front) to F (rear) proximates 1.5 to 1,
By varying the magnitude of the forces F (front) and
F (rear), any number of distance combinations can be pro-
vided to still maintain F (front)' equal to F (rear)'.
It also should be pointed out that the connecting
rods 52 and 54 and the floating lever 56 can be positioned on
an oppocite side of the truck 10, i.e. adjacent to the rear
wheelset 14 rather than the front wheelset 12 by merely
reversing the position of truck levers 40, 42, i.e. the
U-shaped truck lever 40 is adjacent to the wheelset 14 while
the elongated truck lever 42 is adjacent to the wheelset 12.
If the braking system is activated when the wheel- -
sets 12 and 14 are in an out-of-square position with respect
to the longitudinal axis of the truck 10, the force F does
not affect this out-of-square position as the front brake
shoes 62, 64 engage the front wheelset 12 and the rear
brake shoes 70l 72 engage the rear wheelset 14. As an
example, if the truck 10 encounters a left-hand curved
section in trackage on which the car truck 10 is traveling
in the direction D, the front wheelset 12 rotates counter-
clockwise while the rear wheelset 14 rotates clockwise.
Becat~se the front swingable arm bracket 36 is offset from
the axis of rotation, the bracket 36 will likewise rotate
causing a complementary change in position of the front
brake beam 58 through the front truck lever 40. The truck
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Case 5574
4423
lever 40 causes this change in position of the front brake
beam 58 because a pivot 74 formed between the front
bracket 36 and the truck lever 40 is vertical while a
pivot 76 formed between the truck lever 40 and the front
brake beam 58 is angularly inclined.
~ similar condition exists between the rear swingable
arm bracket 38, the rear truck lever 42 and the rear brake
beam 66 where respective pivots 78, 80 are positioned
parallel but angularly offset to a plane of rotation of
iO the wheelset 14 so that a rotation of the rear wheelset 14
causes a complementary rotational movement of the rear
bracket 38, the rear truck lever 42 and rear brake beam 66. -~
Dur~ng operation, a linear braking force, as an
example force F, is applied to the floating lever 56. The
force F- may be divided into two equal force components,
as an example F (front) and F (rear), and transferred .o
the front and rear truck levers 40 and 42 by the connecting
rods 52 and 54. The force components cause a rotation of
the front and the rear truck levers 40 and 42 about the
pi~ot 74, 80 formed with the front and rear swingable
arm brackets 36 and-38. This rotation causes an equal
but opposite linear force to be applied to the front and
rear brake beams 58 and 66 so that the front brake
shoes 62, 64 and the rear brake shoes 70, 72 engage the
front and rear whPelsets 12 and 14 respectively.

~ Case 5574
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While various modifications may be suggested by :
those versed in the art, it should be understood that I
wish to embody within the scope of the patent warranted
hereon all such modifications as reasonably and properly
S come within the scope of my contribution to the art.
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