Note: Descriptions are shown in the official language in which they were submitted.
1
Friction End-of-Car Cushioning Assembly
TECHNICAL FIELD
This disclosure relates generally to railcars and, more particularly, to a
railcar
coupler system.
BACKGROUND
Railcars that carry sensitive lading, such as box cars, flat cars, and coil
cars,
require protection from the high impact forces that can develop when railcars
are
impacted into one another in classification yards. This protection is provided
by two
distinct types of "shock absorbing" devices. For railcars where the lading is
not
subject to damage, such as coal and grain cars, a short travel (e.g. less than
5") unit
called a draft gear is used. These units predominantly use friction as a means
of
absorbing the energy of impact. When the lading is more likely to be damaged,
such
as consumer products, a longer travel unit (e.g. 10", 15", or 18") is used.
These units
are universally hydraulic and are referred to as an end-of-car cushioning
(EOC) units.
Hydraulic E0Cs are excellent at protecting railcars and lading from impact
damage.
However, hydraulic E0Cs tend to leak, are expensive, and their softness
produces
excessive train action forces in service. It is desirable to provide a
solution that
overcomes the problems associated with hydraulic E0Cs while providing adequate
protection for railcars and lading.
Date Recue/Date Received 2020-06-09
2
SUMMARY
In one embodiment, the disclosure includes a friction end-of-car cushioning
(EOC) assembly with a housing coupled to a railcar. The housing has a chamber
formed within a bore of the housing that includes a first contact surface
comprising an
angled contact surface at a first end of the chamber and a second contact
surface at a
second end of the chamber. The friction EOC assembly also includes a center
shaft
disposed at least partially within the bore of the housing. The center shaft
has a head
portion at a first end of the center shaft, a coupler interface at a second
end of the
center shaft, and a rod portion spanning between the head portion and the
coupler
interface. The rod portion of the center shaft is tapered from the second end
of the
center shaft to the first end of the center shaft.
The friction EOC assembly also includes a sliding wedge disposed within the
chamber. The sliding wedge has a first contact surface tapered toward the
first contact
surface of the housing, a second contact surface perpendicular to the bore of
the
housing, and a third contact surface parallel to the bore of the housing. The
sliding
wedge is positioned to allow the rod portion of the center shaft to pass
through a bore
defined by the third contact surface of the sliding wedge. The sliding wedge
is also
configured such that the first contact surface of the sliding wedge is
positioned to
apply a force onto the angled contact surface of the housing and the third
contact
surface of the sliding wedge is positioned to apply a frictional force to the
rod portion
of the center shaft.
The friction EOC assembly also includes a load spring disposed within the
chamber. The load spring is positioned to allow the rod portion of the center
shaft to
pass through a bore of the load spring. The load spring is compressed between
the
second contact surface of the chamber and the second contact surface of the
sliding
wedge and is positioned to apply a compressive force onto the second contact
surface
of sliding wedge toward the angled contact surface of the housing. The load
spring is
configured to not further compress as the center shaft moves within the bore
of the
housing.
In another embodiment, the disclosure includes a damping method that
involves configuring a friction EOC assembly on a railcar in a first
configuration. In
Date Recue/Date Received 2020-06-09
3
the first configuration, a head portion of a center shaft is positioned
adjacent to a
chamber formed within a bore of a housing. The method further involves
applying a
force onto a coupler interface portion of the center shaft in a direction
toward the first
end of the chamber to transition the friction end-of-car cushioning assembly
to a
second configuration. Applying the force onto the center shaft moves the head
portion
of the center shaft away from the chamber and moves the coupler interface
portion of
the center shaft toward the chamber.
In yet another embodiment, the disclosure includes a damping method that
involves configuring a friction EOC assembly on a railcar in a first
configuration. In
the first configuration, a coupler interface portion of a center shaft is
positioned
adjacent to a chamber formed within a bore of a housing. The method involves
applying a force onto the coupler interface portion of the center shaft in a
direction
away the first end of the chamber to transition the friction end-of-car
cushioning
assembly to a second configuration. Applying the force onto the center shaft
moves a
head portion of the center shaft toward the chamber and moves the coupler
interface
portion of the center shaft away the chamber.
Disclosed herein are various embodiments of a friction EOC assembly for a
railcar that provide several technical advantages. After a rapid rise in
force, the force
generated by the friction EOC assembly is essentially constant since the
spring is pre-
compressed and the compression on it does not change significantly during the
stroke.
In one embodiment, the friction EOC assembly is entirely mechanical and does
not
involve hydraulics, which allows the friction EOC assembly to be less
expensive and
more reliable than hydraulic E0Cs. In one embodiment, the friction EOC
assembly
can be incorporated into a draft sill and does not require an additional
housing, which
may reduce weight and cost. The friction EOC assembly force levels can be
adjusted
by changing spring stiffness, spring pre-compression, and/or wedge angles. The
friction EOC assembly design allows the friction EOC assembly to have any
length of
draft gear travel, and does not restrict travel of draft gear unlike existing
systems.
Certain embodiments of the present disclosure may include some, all, or none
of these advantages. These advantages and other features will be more clearly
understood from the following detailed description taken in conjunction with
the
accompanying drawings and claims.
Date Recue/Date Received 2020-06-09
4
BRIEF DESCRIPTION OF THE DRAWINGS
For a more complete understanding of this disclosure, reference is now made
to the following brief description, taken in connection with the accompanying
drawings and detailed description, wherein like reference numerals represent
like
parts.
FIG. 1 is a side view of a railcar system using a friction end-of-car
cushioning
(EOC) assembly to couple railcars;
FIG. 2 is a cutaway view of an embodiment of a friction EOC assembly in a
first configuration;
FIG. 3 is a cutaway view of an embodiment of the friction EOC assembly in a
second configuration;
FIG. 4 is a cutaway view of another embodiment of a friction EOC assembly;
FIG. 5 is partial cutaway view of an embodiment of a wedge configuration for
the friction EOC assembly;
FIG. 6 is partial cutaway view of another embodiment of a wedge
configuration for the friction EOC assembly;
FIG. 7 is partial cutaway view of another embodiment of a wedge
configuration for the friction EOC assembly;
FIG. 8 is partial cutaway view of another embodiment of a wedge
configuration for the friction EOC assembly;
FIG. 9 is partial cutaway view of another embodiment of a wedge
configuration for the friction EOC assembly;
FIG. 10 is an embodiment of a damping method using a friction EOC
assembly;
FIG. 11 is a partial cutaway view of a portion of another embodiment of a
friction EOC assembly in a first configuration;
FIG. 12 is a partial cutaway view of a portion of another embodiment of a
friction EOC assembly in a second configuration;
FIG. 13 is a partial cutaway view of another embodiment of a friction EOC
assembly;
FIG. 14 is a cross section view of an embodiment of sliding wedge segments
within the housing of a friction EOC assembly;
Date Recue/Date Received 2020-06-09
5
FIG. 15 is a cross section view of another embodiment of sliding wedge
segments within the housing of a friction EOC assembly;
FIG. 16 is a cross section view of another embodiment of sliding wedge
segments within the housing of a friction EOC assembly;
FIG. 17 is a cross section view of another embodiment of sliding wedge
segments within the housing of a friction EOC assembly;
FIG. 18 is a cross section view of another embodiment of sliding wedge
segments within the housing of a friction EOC assembly; and
FIG. 19 is a partial cutaway view of a portion of another embodiment of a
friction EOC assembly.
Date Recue/Date Received 2020-06-09
6
DETAILED DESCRIPTION
Conventional friction draft gears use friction wedges backed by a spring that
compresses as the draft gear is compressed. These types of friction draft
gears cannot
be extended to have significantly longer travel. As the spring is compressed,
the
spring applies a force on the wedges and the friction resisting compression of
the draft
gear increases. The force generated by these systems is a roughly linear
increase of
force with compression. However, the design of conventional draft gear limits
its
travel to about 4" to 5" due to the maximum practical compression of the
spring.
Conventional hydraulic end-of-car cushionings (E0Cs) exhibit a rapid rise in
force to
an approximately constant level. This application of force allows hydraulic
E0Cs to
absorb more energy than conventional friction draft gears. Hydraulic E0Cs are
more
effective than even multiple friction draft gears in tandem.
Disclosed herein are various embodiments of a friction EOC assembly for a
railcar. After a rapid rise in force, the force generated by the friction EOC
assembly is
essentially constant since the spring is pre-compressed and the compression on
it does
not change significantly during the stroke. In one embodiment, the friction
EOC
assembly is entirely mechanical and does not involve hydraulics, which allows
the
friction EOC assembly to be less expensive and more reliable than hydraulic
E0Cs. In
one embodiment, the friction EOC assembly can be incorporated into a draft
sill and
does not require an additional housing, which may reduce weight and cost. The
friction EOC assembly force levels can be adjusted by changing spring
stiffness,
spring pre-compression, and/or wedge angles. The friction EOC assembly design
allows the friction EOC assembly to have any length of draft gear travel, and
does not
restrict travel of draft gear unlike existing systems.
In some embodiments, the friction EOC assembly can be used as a direct
replacement for existing hydraulic E0Cs. The friction EOC assembly may be
configured to integrate with existing end fittings for hydraulic E0Cs. For
example,
the friction EOC assembly may be configured with the same interface on the
ends of
the center shaft to allow the friction EOC assembly to be retrofitted to
existing
systems.
Date Recue/Date Received 2020-06-09
7
FIG. 1 is a side view of a railcar system 100 using a friction EOC assembly
200 to couple railcars 102A and 102B. Examples of railcars 102A and 102B
include,
but are not limited to, box cars, flat cars, autorack cars, tank cars, hopper
cars, coil
cars, or any other suitable type of railcar. The friction EOC assembly 200 is
generally
configured to protect railcars 102A and 102B and their payloads by dampening
the
high impact forces that can develop when the railcars 102A and 102B are
impacted
into one another. For example, the friction EOC assembly 200 may provide shock
absorption when the railcars 102A and 102B are coupled to each other.
FIG. 2 is a cutaway view of an embodiment of a friction EOC assembly 200 in
a first configuration. The friction EOC assembly 200 comprises a housing 202,
a load
spring 204, a sliding wedge 206, a backing wedge 208, a center shaft 210, a
coupler
212, and a draft spring 214. The friction EOC assembly 200 may be configured
as
shown or in any other suitable configuration.
The housing 202 comprises an axial bore 203 that allows the center shaft 210
to move within the bore 203 of the housing 202. The housing 202 may be
constructed
using metals or any other suitable material. The housing 202 structure may be
a
square, circular, hexagonal, or any other suitable shape along the length of
the
housing 202. In other words, the housing 202 comprise a circular cross
section, a
rectangular cross section, a hexagonal cross section, or any other suitable
shape cross
section. In one embodiment, the housing 202 is supported by a draft stop
welded to
the draft sill, which allows the housing 202 to remain in a fixed position as
the center
shaft 210 slides through the housing 202.
The center shaft 210 comprises a head portion 209, a rod portion 211, and a
coupler interface portion 213. The head portion 209 is located at a first end
of the
center shaft 210. The coupler interface portion 213 is located at a second end
of the
center shaft 210. The rod portion 211 spans between the head portion 209 and
the
coupler interface portion 213 of the center shaft 210. The rod portion 211
comprise a
circular cross section, a rectangular cross section, or any other suitable
shape cross
section. In one embodiment, the head portion 209 and/or the coupler interface
portion
213 have a circumferential diameter larger than the diameter of the rod
portion 211 of
the center shaft 210. The coupler interface portion 213 of the center shaft
210 is
coupled to a coupler 212 which may be used to connect a railcar with the
friction
Date Recue/Date Received 2020-06-09
8
EOC assembly 200 to another railcar. The coupler 212 may be any suitable type
of
coupler for connecting railcars.
The center shaft 210 is disposed at least partially within the bore 203 of the
housing 202. The center shaft 210 is positioned such that at least a portion
(e.g. the
rod portion 211) of the center shaft 210 passes through the chamber 205 of the
housing 202. In FIG. 2, the center shaft 210 is shown in an extended position,
such
that the center shaft 210 is extending in a direction out of the housing 202
and toward
the coupler 212. The center shaft 210 is configured to move (e.g. slide)
within the
bore 203 of the housing 202.
The center shaft 210 may have any suitable length 220 and/or stroke length
222. For example, the center shaft 210 may have a length 220 of about 30
inches (in)
and a stroke length 222 of about 10 in. In other examples, the center shaft
210 may be
any other suitable length 220 and/or stroke length 222. The center shaft 210
structure
may be a square, circular, hexagonal, or any other suitable shape along the
length of
the center shaft 210.
The housing 202 comprises a chamber 205 configured to house the load spring
204, the sliding wedge 206, and the backing wedge 208. The chamber 205 is
formed
within the bore 203 of the housing 201. The chamber 205 is configured to allow
a rod
portion 211 of the center shaft 210 to pass through an opening or bore formed
by the
chamber 205.
The backing wedge 208 is disposed within the chamber 205 such that at least a
portion of the backing wedge 208 is in contact with a first contact surface
215 at a
first end of the chamber 205. The backing wedge 208 comprises an angled
contact
surface 219. The angled contact surface 219 is a surface that tapers away from
the
first end of the chamber 205. The angled contact surface 219 may have suitable
angle
or rate of tapering. The backing wedge 208 is positioned to allow the rod
portion 211
of the center shaft 210 to pass through a bore or opening defined by the
angled contact
surface 219 of the backing wedge 208.
The sliding wedge 206 is disposed within the chamber 205. The sliding wedge
206 comprises a first contact surface 224 tapered toward the first contact
surface 215
of the chamber 205. The first contact surface 224 of the sliding wedge 206 is
positioned to apply a force (e.g. a compressive force and/or a frictional
force) onto the
Date Recue/Date Received 2020-06-09
9
angled contact surface 219 of the backing wedge 208. The sliding wedge 206
comprises a second contact surface 226 configured substantially perpendicular
to the
bore 203 of the housing 202. The sliding wedge 206 comprises a third contact
surface
228 configured substantially parallel to the bore 203 of the housing 202. The
sliding
wedge 206 is positioned to allow the rod portion 211 of the center shaft 210
to pass
through a bore or opening defined by the third contact surface 228 of the
sliding
wedge 206. In addition, the third contact surface 228 is at least partially in
contact
with the rod portion 211 of the center shaft 210 and is positioned to apply a
frictional
force onto the rod portion 211 of the center shaft 210.
The load spring 204 is disposed within the chamber 205. Examples of the load
spring 204 include, but are not limited to, coil springs, elastomer springs,
and rubber
dampeners. The load spring 204 is positioned to allow the rod portion 211 of
the
center shaft 210 to pass within a bore or opening defined by the load spring
204. The
load spring 204 is configured to be pre-compressed within the chamber 205. The
load
spring 204 is compressed between a second contact surface 216 at a second end
of the
chamber 205 and the second contact surface 226 of the sliding wedge 206. In
such a
configuration, the load spring 204 is configured to apply a compressive force
to the
second contact surface 226 of the sliding wedge 206 toward the angled contact
surface 219 of the backing wedge 208.
Unlike conventional friction draft gears which use a spring that is initially
unloaded, the load spring 204 is configured to be preloaded (i.e. pre-
compressed)
which constantly applies a force to the sliding wedge 206. Although the load
spring
204 is shown as an elastomeric spring, the load spring 204 may be any other
suitable
type of spring or mechanism. The force applied to the end of the sliding wedge
206
causes the sliding wedge 206 to apply a force to both the angled contact
surface 219
of the backing wedge 208 and the rod portion 211 of the center shaft 210. The
force
applied to the center shaft 210 by the sliding wedge 206 results in friction
between the
center shaft 210 and the sliding wedge 206. In one embodiment, the load spring
204 is
configured to not further compress as the center shaft 210 moves within the
bore 203
of the housing 202. In other words, the compression of the load spring 204
remains
substantially constant when the center shaft 210 moves within the bore 203 of
the
housing 202.
Date Recue/Date Received 2020-06-09
10
In one embodiment, the friction EOC assembly 200 comprises a draft spring
214 disposed within the housing 102. Examples of the draft spring 214 include,
but
are not limited to, coil springs, elastomer springs, and rubber dampeners. The
draft
spring 214 is positioned between the head portion 209 of the center shaft 210
and a
third contact surface 217 at the first end of the chamber 205. The draft
spring 214 is
configured such that the rod portion 211 of the center shaft 210 passes
through the
draft spring 214. The draft spring 214 is configured to provide cushioning to
the
center shaft 210 by applying a force to the head portion 209 of the center
shaft 210
when the center shaft 210 extends out of the housing 202. Without the draft
spring
214, the head portion 209 of the center shaft 210 would make contact with the
third
contact surface 217 of the chamber 205 which would cause the center shaft 210
to
stop abruptly at full travel. Although the draft spring 214 is shown as an
elastomeric
spring, the draft spring 214 may be any other suitable type of spring or
mechanism. In
some embodiments, the draft spring 214 is optional.
FIG. 3 is a cutaway view of an embodiment of the friction EOC assembly 200
in a second configuration. In FIG. 3, the center shaft 210 is shown in a
retracted
position, such that the center rod 200 is retracted into the housing 202.
During an
impact event, the center shaft 210 is pushed into the housing 202. The load
spring 204
constantly applies a force to the second contact surface 226 of the sliding
wedge 206,
which pushes the sliding wedge 206 down the slope of the angled contact
surface 219
of the backing wedge 208 between the center shaft 210 and the backing wedge
208.
This produces a magnified normal force between the sliding wedge 206 and the
center
shaft 210. This force resists the motion of the center shaft 210 and absorbs
the energy
of impact. The motion of the center shaft 210 also enhances the wedge action
and
further increases the force.
FIG. 4 is a cutaway view of another embodiment of a friction EOC assembly
200. In one embodiment, the friction EOC assembly 200 comprises a return
spring
402 disposed within the housing 202. Examples of the return spring 402
include, but
are not limited to, coil springs, elastomer springs, and rubber dampeners. The
return
spring 402 is positioned between the coupler interface 213 and a fourth
contact
surface 218 at the second end of the chamber 205. The return spring 402 is
configured
to allow the rod portion 211 of the center shaft 210 to pass through the
return spring
Date Recue/Date Received 2020-06-09
11
402. The return spring 402 is configured such that when a force is no longer
pushing
the center shaft 210 into the housing 202, the return spring 402 pushes the
center shaft
210 back into the extended position, for example, as shown in FIG. 1. Although
the
return spring 402 is shown as a coil spring, the return spring 402 may be any
other
suitable type of spring or mechanism. In some embodiments, the return spring
402 is
optional.
FIG. 5 is partial cutaway view of an embodiment of a wedge configuration for
the friction EOC assembly 200. In one embodiment, the friction EOC assembly
200
comprises a spring or an elastomer liner 502 between the first contact surface
224 of
the sliding wedge 106 and the angled contact surface 219 of the backing wedge
108.
In this configuration, the friction EOC assembly 200 is configured such that
the
sliding wedge 206 and the backing wedge 208 do not slide past each other. The
elastomer liner 502 is configured to deflect in shear, which allows motion for
the
sliding wedge 206. Such a configuration may be more consistent than only
relying on
friction. In one embodiment, the elastomer liner 502 could also represent a
low
friction lining material between the sliding wedge 206 and the backing wedge
208. In
this configuration, the low friction between the sliding wedge 206 and the
backing
wedge 208 may produce more consistent and lower friction which may enhance the
operation of the sliding wedge 206.
FIG. 6 is partial cutaway view of another embodiment of a wedge
configuration for the friction EOC assembly 200. In one embodiment, the
friction
EOC assembly 200 comprises an insert 602 between the third contact surface 228
of
the sliding wedge 206 and the rod portion 211 of the center shaft 210. The
insert 602
may be a sliding material such as a brake lining material which could provide
improved friction characteristics. In some embodiments, the insert 602 may be
produced by inserting slugs of lubrication material onto slots in the faces
(e.g. the
third contact surface 228) of the sliding wedge 206 and the rod portion 211 of
the
center shaft 210. In this example, the lubrication material is spread over the
surface as
the center shaft 210 slides to form the insert 602.
FIG. 7 is partial cutaway view of another embodiment of a wedge
configuration for the friction EOC assembly 200. In one embodiment, the first
contact
surface 224 of the sliding wedge 206 has a rounded surface. For example, the
sliding
Date Recue/Date Received 2020-06-09
12
wedge 206 may be configured such that first contact surface 224 of the sliding
wedge
206 has a curved or rounded surface. The first contact surface 224 of the
sliding
wedge 206 may have any suitable amount of curvature or roundedness. The
curvature
of the sliding wedge 206 may allow the sliding wedge 206 to properly align
with the
center shaft 210 even if the backing wedge 208 is not at exactly the correct
angle or is
not flat. Properly aligning the center shaft 210 may help the friction EOC
assembly
200 generate more force for absorbing energy.
FIG. 8 is partial cutaway view of another embodiment of a wedge
configuration for the friction EOC assembly 200. In one embodiment, the
backing
wedge 208 is formed by the chamber 205. In other words, an interior portion of
the
chamber is configured to serve as the previously described backing wedge 208.
FIG. 9 is partial cutaway view of another embodiment of a wedge
configuration for the friction EOC assembly 200. In one embodiment, the
backing
wedge 208 is configured into a cone shape. The sliding wedge 106 is configured
to be
curved and to fit within the cone shape structure of the backing wedge 208.
In one embodiment, the sliding wedge 206 comprises a plurality of sliding
wedge segments 902 and a plurality of elastomer lining segments 904. Each of
the
plurality of elastomer lining segments 904 may be disposed between a pair of
sliding
wedge segments 902 from the plurality of sliding wedge segments 902. In this
example, the sliding wedges 902 are evenly spaced by inserting a soft
elastomer 904
between the sliding wedges 902. The sliding wedge 206 may comprise any
suitable
number of sliding wedge segments 902 and/or elastomer lining segments 904. In
addition, the elastomer lining segments 904 may have any suitable thickness.
FIG. 10 is an embodiment of a damping method 1000 using a friction EOC
assembly 200. An operator may employ method 1000 with the friction EOC
assembly
200 to provide shock absorption when connecting two railcars together.
At step 1002, an operator configures the friction EOC assembly 200 on a
railcar in a first configuration. In the first configuration, the friction EOC
assembly
200 may be configured with the center shaft 210 positioned similar to the
configuration shown in FIG. 2.
At step 1004, a first force is applied onto the coupler interface portion 213
of
the center shaft 210 in a first direction toward the first end of the chamber
205 to
Date Recue/Date Received 2020-06-09
13
transition the friction EOC assembly 200 to a second configuration. For
example, as
the railcars begin to engage each other, the coupler 212 attached to the
coupler
interface portion 213 of the center shaft 210 may experience a force that
moves the
coupler interface portion 213 of the center shaft 210 toward the chamber 205
and
moves the head portion 209 of the center shaft 210 away the chamber 205. In
the
second configuration, the friction EOC assembly 200 may be configured with the
center shaft 210 positioned similar to the configuration shown in FIG. 3.
At step 1006, a second force is applied onto the coupler interface portion 213
of the center shaft 210 in a second direction away from the first end of the
chamber
205 to transition the friction EOC assembly 200 back to the first
configuration. For
example, as the railcars begin to separate from each other, the coupler 212
attached to
the coupler interface portion 213 of the center shaft 210 may experience a
force that
moves the coupler interface portion 213 of the center shaft 210 away the
chamber 205
and moves the head portion 209 of the center shaft 210 toward the chamber 205.
In
one embodiment, the second force is applied to the coupler interface portion
213 of
the center shaft 210 by a return spring (e.g. return spring 402). In another
embodiment, the second force is applied to the coupler interface portion 213
of the
center shaft 210 by the coupler 212 pulling away from the friction EOC
assembly
200. In other embodiments, the second force is applied to the coupler
interface portion
213 of the center shaft 210 by any other suitable method as would be
appreciated by
one of ordinary skill in the art upon viewing this disclosure.
FIG. 11 is a partial cutaway view of a portion of another embodiment of a
friction EOC assembly 200 in a first configuration. In FIG. 11, the diameter
1114 of
the rod portion 211 of the center shaft 210 is tapered in a direction from the
coupler
interface portion 213 at the second end of the center shaft 210 to the head
portion 209
at the first end of the center shaft 210. The tapering of the rod portion 211
of the
center shaft 210 causes the diameter 1114 of the center shaft 210 to vary
along the
length of the rod portion 211 of the center shaft 210. In some embodiments,
the rod
portion 211 of the center shaft 210 may be configured such that different
portions of
the center shaft 210 have different tapering rates. For example, the rod
portion 211 of
the center shaft 210 may comprise a first tapered portion 1106 and a second
tapered
portion 1108. In this example, the first tapered portion 1106 may taper at a
greater
Date Recue/Date Received 2020-06-09
14
rate than the second tapered portion 1108. In other words, the diameter 1114
of the
first tapered portion 1106 may reduce more rapidly than the diameter 1114 of
the
second tapered portion 1108. The tapering of the center shaft 210 effectively
causes
the diameter 1114 of the center shaft 210 to increase as the center shaft 210
moves in
the first direction 1110. This causes the closing force of the friction EOC
assembly
200 to increase which allows for a less abrupt slowing of a railcar under low
velocity
impacts and a higher force under high velocity impacts. The center shaft 210
may
have a cross section that is a rectangular, circular, hexagonal, or any other
suitable
shape along the length of the center shaft 210.
In FIG. 11, the previously described backing wedge 208 may be integrated
within the chamber 205 of the housing 202. For example, the chamber 205 may
comprise an angled contact surface 1102 that operates similar to the backing
wedge
208 described in FIG. 2. In the first configuration, the sliding wedge 206 is
configured
to move along the angled contact surface 1102 as the center shaft 210
traverses the
bore 203 of the housing 202. As the center shaft 210 traverses the bore 203 of
the
housing 202 in a first direction 1110, the diameter 1114 of the rod portion
211 of the
center shaft 210 that passes through the sliding wedge 206 increases. The
increasing
diameter 1114 of the center shaft 210 causes the sliding wedge 206 move or
expand
outwardly toward the sidewalls of the housing 202. An example of the sliding
wedge
206 moving outwardly toward the sidewalls of the housing 202 is shown in FIG.
12.
As the center shaft 210 traverses the bore 203 of the housing 202 in a second
direction
1112, the diameter 1114 of the rod portion 211 of the center shaft 210 that
passes
through the sliding wedge 206 decreases. The decreasing diameter 1114 of the
center
shaft 210 causes the sliding wedge 206 move or contract inwardly toward the
bore
203 of the housing 202.
In one embodiment, the friction EOC assembly 200 may comprise a spring
seat or backing plate 1104 disposed between the sliding wedge 206 and the load
spring 204. In this configuration, the load spring 204 is configured to apply
a force
onto the sliding wedge 206 via the spring seat 1104.
FIG. 12 is a partial cutaway view of a portion of another embodiment of a
friction EOC assembly 200 in a second configuration. In the second
configuration, the
sliding wedge 206 has moved or expanded outwardly toward the sidewalls of the
Date Recue/Date Received 2020-06-09
15
housing 202. In this configuration, the normal force between the sliding wedge
206
and the center shaft 210 is magnified. This force resists the motion of the
center shaft
210 and absorbs the energy of an impact. The motion of the center shaft 210
also
enhances the wedge action between the sliding wedge 206 and the angled contact
surface 1102of the housing 202 which further increases the resistive force.
FIG. 13 is a partial cutaway view of another embodiment of a friction EOC
assembly 200. In FIG. 13, the angled contact surface 1102 of the housing 202
is
curved toward the sliding wedge 206. In addition, the first contact surface
215 of the
sliding wedge 206 is curved away from the angled contact surface 1102 of the
housing 202 to substantially match the curvature of the angled contact surface
1102 of
the housing 202. The angled contact surface 1102 of the housing 202 and the
first
contact surface 215 of the sliding wedge 206 may each have any suitable amount
of
curvature or roundness. The curvature of the angled contact surface 1102 of
the
housing 202 and the first contact surface 215 of the sliding wedge 206 may
prevent or
mitigate the ends of the sliding wedge 206 from rotating against the angled
contact
surface 1102 of the housing 202.
In one embodiment, the third contact surface 228 of the sliding wedge 206
may be curved toward the center shaft 210. The curvature of the third contact
surface
228 of the sliding wedge 206 may allow the amount of friction and force
between the
sliding wedge 206 and the center shaft 210 to vary as the center shaft 210
traverses
the bore 203 of the housing 202.
In some embodiments, one of the angled contact surface 1102 or the first
contact surface 215 of the sliding wedge 206 may be curved while the other
contact
surface remains flat. For example, the angled contact surface 1102 may be flat
while
the first contact surface 215 of the sliding wedge 206 is curved. In this
example, the
first contact surface 215 of the sliding wedge 206 may be curved in a
direction toward
the angled contact surface 1102. In this configuration, the point of contact
between
the angled contact surface 1102 and the first contact surface 215 of the
sliding wedge
206 moves outward as the sliding wedge 206 rotates when the center shaft 210
traverses the bore 203 of the housing 202.
FIGS. 14-18 are cross-sectional views of examples of different configurations
for sliding wedge segments 206 within the housing 202 of friction EOC assembly
Date Recue/Date Received 2020-06-09
16
200. As an example, the cross-sectional views may be from location 1116 shown
in
FIG. 11. In FIGS. 14-18, the housing 202 has a rectangular cross section that
comprises four edges 1402 (e.g. sidewalls) and four corners 1404. In this
example, the
center shaft 210 also has a rectangular cross section that comprises four
edges 1406
and four corners 1408. The sliding wedge segments 206 may be configured to be
in
different shapes and/or positions within the housing 202. FIGS. 14-18
illustrate
examples with four sliding wedge segments 206. In other examples, the friction
EOC
assembly 200 may comprise any other suitable number of sliding wedge segments
206.
FIG. 14 is a cross section view of an embodiment of sliding wedge segments
206 within the housing of a friction EOC assembly 200. In FIG. 14, each
sliding
wedge segment 206 has a rectangular cross section and is configured to apply a
force
to an edge 1402 of the housing 202 and an edge 1406 of the center shaft 210.
FIG. 15 is a cross section view of another embodiment of sliding wedge
segments 206 within the housing of a friction EOC assembly 200. In FIG. 15,
each
sliding wedge segment 206 has a trapezoidal cross section and is configured to
apply
a force to an edge 1402 of the housing 202 and an edge 1406 of the center
shaft 210.
In this configuration, the sliding wedge segments 206 have a larger contact
surface
with the edge 1402 of the housing 202 compared to the sliding wedge segment
206
configuration described in FIG. 14. The larger contact surface provides
increased
stiffening of the housing 202 against frictional forces.
FIG. 16 is a cross section view of another embodiment of sliding wedge
segments 206 within the housing of a friction EOC assembly 200. In FIG. 16,
each
sliding wedge segment 206 has a rectangular cross section and is configured to
apply
a force to two edges 1402 and a corner 1404 of the housing 202 and two edges
1406
and a corner 1408 of the center shaft 210. In this configuration, the corners
1404 of
the housing 202 and the corners 1408 of the center shaft 210 may act as guides
for the
sliding wedge segments 206.
FIG. 17 is a cross section view of another embodiment of sliding wedge
segments 206 within the housing of a friction EOC assembly 200. In FIG. 17,
each
sliding wedge segment 206 has a rectangular cross section and is configured to
apply
a force to two edges 1402 and a corner 1404 of the housing 202 and an edge
1406 of
Date Recue/Date Received 2020-06-09
17
the center shaft 210. In this configuration, the center shaft 210 is rotated
45 degrees
from the example shown in FIG. 16.
FIG. 18 is a cross section view of another embodiment of sliding wedge
segments within the housing of a friction EOC assembly 200. In FIG. 18, each
sliding
wedge segment 206 has a rectangular cross section and is configured to apply a
force
to two edges 1402 and a corner 1404 of the housing 202 and an edge 1406 of the
center shaft 210. In this configuration, the friction EOC assembly 200 further
comprises a low modulus material 1802 disposed between the sliding wedge
segments
206 and the housing 202. In one embodiment, the low modulus material 1802 has
an
elastic modulus that is less than steel. Examples of the low modulus material
1802
include, but are not limited to, a polymer material, a hard rubber, rubber,
urethane,
and any other suitable type of material. The low modulus material 1802 may be
formed to be any suitable shape or thickness. An expansion force is applied to
the
housing 202 as the sliding wedge segments 206 move along the angled contact
surface 1102 of the housing 202. The low modulus material 1802 provides
increased
stiffening to the sidewalls housing 202 to mitigate any expansion of the
housing 202
due to the expansion force.
FIG. 19 is a partial cutaway view of a portion of another embodiment of a
friction EOC assembly 200. In FIG. 19, the friction EOC assembly 200 is
configured
similar to the friction EOC assembly 200 described in FIG. 18. For example,
the
friction EOC assembly 200 comprises a low modulus material 1802 disposed
between
the sliding wedge segments 206 and the housing 202 similar to the low modulus
material 1802 described in FIG. 18. In FIG. 19, the friction EOC assembly 200
comprises a semi-static block 1902 that is interlocked with a fixed shear
backer 1904.
In this configuration, the semi-static block 1902 is configured to provide the
angled
contact surface 1102 for the housing 202. The fixed shear backer 1904 is
configured
to prevent lateral movement of the semi-static block 1902 as the center shaft
210
traverses the housing 202.
One of ordinary skill in the art would appreciate that the various
configurations of the friction EOC assembly 200 described in FIGS. 1-19 may be
combined and/or used interchangeably with each other. For example, the
friction EOC
assembly 200 may comprise any suitable combination and configuration of
Date Recue/Date Received 2020-06-09
18
components as described in FIGS. 1-19. In addition, one of ordinary skill in
the art
would appreciate that the configurations of the friction EOC assembly 200
described
in FIGS. 1-19 may be used with the dampening method 1000 described in FIG. 10.
While several embodiments have been provided in the present disclosure, it
should be understood that the disclosed systems and methods might be embodied
in
many other specific forms without departing from the spirit or scope of the
present
disclosure. The present examples are to be considered as illustrative and not
restrictive, and the intention is not to be limited to the details given
herein. For
example, the various elements or components may be combined or integrated in
another system or certain features may be omitted, or not implemented.
In addition, techniques, systems, subsystems, and methods described and
illustrated in the various embodiments as discrete or separate may be combined
or
integrated with other systems, modules, techniques, or methods without
departing
from the scope of the present disclosure. Other items shown or discussed as
coupled
or directly coupled or communicating with each other may be indirectly coupled
or
communicating through some interface, device, or intermediate component
whether
electrically, mechanically, or otherwise. Other examples of changes,
substitutions, and
alterations are ascertainable by one skilled in the art and could be made
without
departing from the spirit and scope disclosed herein.
To aid the Patent Office, and any readers of any patent issued on this
application in interpreting the claims appended hereto, applicants note that
they do not
intend any of the appended claims to invoke 35 U.S.C. 112(f) as it exists on
the date
of filing hereof unless the words "means for" or "step for" are explicitly
used in the
particular claim.
Date Recue/Date Received 2020-06-09
