Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02526603 2005-11-09
PATENT
Case 0720-0127
LADING TIE ANCHOR LINK WITH ENHANCED BANDING CONTACT SURFACE
Description
Background of the Invention
Field of the Invention
(001] This invention generally relates to an anchor for
securing cargo, using metal banding, onto railway cars
including flatcars, center beams, gondolas and log cars. An
assembly comprising an interlocking retainer and link is used
to decrease the occurrence of banding breakage. The enhanced
radius of the link provides a greater load bearing area for
engaging the banding, thereby reducing the stress present in
the banding when securing heavier and/or top-heavy loads, such
as steel pipe. Special application is found for this approach
in securing heavy loads transported by flatcar.
Description of Related Art
(002] Heavy loads, such as steel pipe and the like, can be
transported in a number of ways, including by flatcar. In
order to prevent the cargo from becoming damaged, it is
necessary to provide securing means. Various known securing
means include plastic strapping, cord strapping, and steel
banding. The preferred way to secure a heavy load is to bind
it with a plurality of steel bands or straps. In practice,
each band is connected to the floor or side frame of the
flatcar by an anchor assembly at opposite sides of the cargo.
Once the band is connected to the anchors and tightened, a
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crimp seal typically is applied to maintain an appropriate
tension level during transport.
[003] Many types of anchor assemblies are well-known. The
"Flexi" anchor assembly made by Ireco LLC is an example of a
known device. Figs. 1-4 illustrate a device 20 according to
the two-piece "Flexi" anchor assembly. The "Flexi" assembly
20 comprises a steel retainer 22 which is affixed to the floor
or frame 24 of a flatcar and a steel link 26 which is movably
connected to the retainer 22. The arcuate retainer 22 takes
the form of an inverted "U" which can be welded to the floor
or frame 24 of the flatcar. The link 26 is triangular and
defines a generally triangular central aperture 28 which
interlocks the retainer 22. The anchor assembly 20 is
configured such that the retainer 22 passes through the
central aperture 28 of the link 26 and effectively hooks the
link 26 to a floor surface or a frame area 24 of the flatcar.
[004] One side 30 of the link 26 includes a banding
portion 32, while the end 34 defined by the intersection of
the other two sides 36 engages the retainer 22. Figs. 1 and 2
show that the banding portion 32 includes a lateral convex
curvature surface 38 facing the central aperture 28. This
part of the banding portion 32 has a radius of curvature "R"
of approximately five inches. Figs. 3 and 4 show that the
cross section 40 of the retainer-engaging end 34 is circular,
while the cross section 42 of the banding portion 32
approximates a rectangle with curved corners. The two corners
44 nearest the central aperture 28 have a 0.25 inch radius of
curvature "r".
[005] In use, a securing means, such as a steel band 46,
is passed through the aperture 28 of the link 26, so as to
engage the banding portion 32. Banding surface 38 is
sufficiently wide to accept a 1.25 inch or 2 inch steel band.
When tension is applied to the steel band 46, it tightens
against the banding portion 32 and deforms in part to take the
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shape of the lateral convex curvature surface 38. Fig. 2
shows in broken lines that the link 26 is free to take an
angled orientation when the steel band 46 engages the banding
surface 38. Fig. 2 also shows in broken lines the use of a
cable or wire 48 extending from an end of the link between two
sides 30 and 36.
L006] The steel band 46 engages a portion of the cross-
sectional perimeter of the banding portion 32 of the link 26,
best shown in broken lines in Fig. 3. The surface of the
banding portion 32 along the link 26 generally conforms to the
opposing, parallel surfaces 50 of the link 26 and the lower
surface 52. The magnitude of the curvature of the steel band
46 about the banding portion 32 is referred to herein as the
banding radius "r". It can be seen that the banding radius
"r" in Fig. 3 varies due to the irregular shape of the banding
portion 32. The lower curved corners 44 each subject the
steel band 46 to a relatively sharp curve, which can result in
creasing of the steel band 46. Fig. 3 also shows the link 26
flat against the floor surface 24 of the flatcar, in a stored
position when it is not in use.
[007] It will be appreciated that a large tensile force
must be applied to the steel bands in order to secure the
cargo. One problem associated with prior art anchor
assemblies which we now have determined to be important is
that, when the steel bands are subjected to such large tensile
forces, especially when combined with forces that result from
even slight shifting of lading weight during the rocking
movement of rail transport, there is the possibility that
metal fatigue will cause the bands to fail. The movement of
rail transport can cause repetitive back and forth bending at
locations where the banding engages a corner or tight radius.
L008] We have determined that the banding radius of anchor
assemblies as illustrated in Figs. 1-4 is inadequate,
especially when used to secure top-heavy or uneven loads, such
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as a load of steel pipes, the steel band can become creased
along the curved corners of the banding portion, which creases
are subjected to dynamic bending forces over time and
subsequently break. This is especially problematic when the
cargo must be transported a great distance. The steel band
can withstand only a certain stress level and will deform and
fail once that level is exceeded. It is thought that the
critical stress level decreases due to the combination of
creasing, dynamic bending forces, and metal fatigue associated
with prior art anchor assemblies. As large tensile forces are
required to safely secure heavier loads, and as heavy
unbalanced loads need to be transported by rail over long
distances, an anchor assembly which reduces the risk of band
breakage is needed.
[009 Figs. 5 and 6 illustrate examples of previous
attempts to solve these band breakage problems. As shown,
both anchors 56 and 58 provide a right cylindrical element 60
having a larger banding portion than that illustrated in Figs.
1-4, while also providing an increased banding radius. The
cylindrical element 60 is separate from the link body 62 and
mounted thereto by a bolt 64, which is itself secured to the
link body 62 by a threaded nut 66.
[0010 It will be appreciated that, in lading anchors for
steel bands, the stress in the steel band is inversely
proportional to the area of the band which engages the banding
portion of the link. Hence, for a given tensile force applied
to the steel band, a larger area of engagement between the
band and the banding portion of the anchor will allow for a
greater force distribution, which decreases the stress to
which the steel band is subjected. An increased banding
radius (perpendicular to the axis of a right cylinder such as
element 60 of Figs. 5 and 6) is also desirable because it
reduces the risk of creasing the steel band which, when
combined with dynamic bending forces, leads to metal fatigue
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and eventually failure at heavier loads. Accordingly, the
anchor assemblies of Figs. 5 and 6 attempt to decrease band
breakage by providing a larger banding portion and right
cylindrical banding radius. The anchor assemblies of Figs. 5
and 6 are relatively expensive because they requi re~several
components (i.e. a cylinder, a bolt, and a nut) to achieve
their goal.
[0011 Accordingly, a general object and aspect of the
present invention is to provide an improved anchor assembly
for use with a railway car such as a flatcar, a center beam
car, a gondola car, a log car and the like.
[0012) Another object or aspect of this invention is to
provide an improved anchor assembly which reduces the risk of
band breakage for heavier loads and those having an unbalanced
or high center of gravity without increasing the number of
components of a current anchor assembly.
[0013 Another object or aspect of the present invention is
to provide an improved anchor assembly and method that address
metal banding breakage problems for top-heavy lading loads,
including those encountered during long-distance rail
transport.
[0014 Other aspects, objects and advantages of the present
invention, including the various features used in various
combinations, will be understood from the following
description according to preferred embodiments of the present
invention, taken in conjunction with the drawings in which
certain specific features are shown.
Summary of the Invention
[0015] In accordance with the present invention, an anchor
assembly reduces the risk of band breakage at large tensile
forces by providing a link with a large load bearing surface
having an enhanced banding portion configuration which
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decreases "creasing" of metal banding that is anchored by the
assembly and decreases bending stress transmitted to the steel
band at the anchor location during rail transport, even over
long distances and with lading loads having a relatively high
center of gravity.
[0016] Notably, a steel link according to the present
invention is made, typically by forging or casting, as a
single component, in contrast to the multiple components used
in the prior art anchor assemblies illustrated in Figs. 5 and
6. It is estimated that a link according to the present
invention costs approximately half as much, or less, to
manufacture and assemble as the Figs. 5 and 6 links, while
achieving performance characteristics at least as advantageous
as those of Figs. 5 or 6.
Brief Description of the Drawings
[0017] Fig. 1 is a top plan view of a prior art anchor
assembly in a stored position;
10018] Fig. 2 is a front elevational view of the anchor
assembly of Fig. 1, with broken lines to illustrate the link-
retainer connection and to show the application of a wire or a
steel band;
[0019] Fig. 3 is a right side cross-sectional view of the
link of Fig. 1, with the retainer in elevation, showing the
link in a stored position and a broken line illustration of a
steel band applied to the link;
[0020] Fig. 4 is a cross-sectional view of the link of the
anchor assembly shown in Fig. 1;
[0021] Fig. 5 is a perspective view of another prior art
anchor assembly having an increased banding radius;
[0022] Fig. 6 is a front elevational view of a further
prior art anchor assembly having an increased banding radius;
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[0023) Fig. 7 is a right side perspective view of an anchor
assembly having an improved link according to the present
invention;
[002] Fig. 8 is a front elevational view of the anchor
assembly of Fig. 7, with broken lines to illustra to the link-
retainer connection;
[0025] Fig. 9 is a right side elevational view of the
anchor assembly of Fig. 7;
[0026] Fig. 9A is a right side cross-sectional view of the
link of Fig. 7, with the retainer in elevation, showing the
link in a stored position and a separate broken line
illustration of the link in use;
10027] Fig. 10 is a top plan view of the anchor assembly
as shown in Fig. 8;
[0028] Fig. 10A is a top plan view of the anchor assembly
as shown in Fig. 8, with an applied steel band;
(00297 Fig. 11 is a bottom plan view of the anchor assembly
as shown in Fig. 8;
[0030] Fig. 11A is a bottom plan view of the anchor
assembly of Fig. 7, with an applied steel band;
[0031] Fig. 12 is a cross-sectional view of the improved
link of Fig. 7, along the line 12-12 of Fig. 8; and
(0032] Fig. 13 illustrates a surface which may be rotated
in order to define the shape of the large load bearing surface
and optional guide flanges of the improved link of Fig. 7,
along the line 13-13 of Fig. 9.
Description of the Preferred Embodiments
[0033) As required, detailed embodiments of the present
invention are disclosed herein; however, it is to be
understood that the disclosed embodiments are merely exemplary
of the invention, which may be embodied in various forms.
Therefore, specific details disclosed herein are not to be
interpreted as limiting, but merely as a basis for the claims
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and as a representative basis for teaching one skilled in the
art to variously employ the present invention and virtually
any appropriate manner.
[0034] Fig. 7 shows an anchor assembly 68 having an
improved link 70 according to the present invention. The
anchor assembly 68 includes the retainer 22 of Fig. 1, which
interlocks the improved link 70 according to the above
description of the prior art anchor assembly 20. The improved
link 70 functions to receive metal banding in the general
sense of the prior art link 26 of Fig. 1. However, as perhaps
best illustrated in Fig. 9A, the large load bearing surface 72
of link 70 is larger than the banding portion 32 and allows
for a greater banding radius "rr". Preferably, the surface 72
has a banding radius "rr" which is between approximately one-
half inch and approximately one and one-half inches. In a
preferred embodiment, this radius "rr" is on the order of
about one inch. Fig. 9A shows that the large load bearing
surface 72 has a cross-sectional area 76 which is
substantially larger than the nominal cross-sectional area 40
of the link 70 at other points, such as at the retainer-
engaging end 34. In contrast, Fig. 4 shows that the cross-
sectional area 42 of the banding portion 32 of the prior art
link 26 is comparable to the,cross-sectional area 40 at the
retainer-engaging end 34.
[0035] Fig. 9A shows that the large load bearing surface 72
approximates a smooth arc along radius "rr", whereas the
banding portion 32 illustrated in Fig. 3 is more U-shaped and
creates isolated zones 44 with small banding radii "r".
Accordingly, due to the improved link 70 of the present
invention, the tensile stress in the steel band 46 is spread
over a greater surface area, there is a reduction in
"creasing" along the radius "rr" when compared with along
radii "r", and the occurrence of band breakage at heavier
and/or relatively unstable loads is decreased. Furthermore,
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it is thought that, under typical transport conditions, an
improved link according to the present invention significantly
reduces or virtually eliminates band breakage by limiting
metal fatigue which, in prior art anchor assemblies, causes
the critical stress level of the metal banding to drop below
the amount resulting from the applied tensile force.
[0036] In an alternate embodiment, the improved link 70 can
include two guide flanges 78 which are shown disposed along
the sides of the large load bearing surface 72. The flanges
78 extend beyond or flank the large load bearing surface 72,
as best shown in Figs. 10 and 10A, and guide the steel band 46
when it is first applied to the link 26, by preventing it from
moving laterally beyond the bounds of the large load bearing
surface 72.
[0037] As shown in Fig. 9A, in the stored position, the
guide flanges 78 can be useful in preventing the large load
bearing surface 72 from coming into contact with the floor
surface 24 of the flatcar. Accordingly, the flanges 78 can
assist in having the large load bearing surface 72 remain
cleaner than when flanges are omitted and allow a true fit for
the steel band 46, when engaged. Also, unlike prior art links
which will freeze to the railway car deck or frame under
winter conditions, flanges 78 minimize the risk of such
freezing, due largely to the minimal surface of the unit
according to the invention that engages the deck or frame of
the car.
[0038] The improved link 70 may include a lateral, convex
curvature 80 along the large load bearing surface 72, in which
event the curvature 80 will have a minimum radius "RR".
Radius "RR" can be substantially constant throughout the
transverse curvature of radius "rr". Fig. 13 shows the shape
of a surface 82 which may be rotated through an obtuse angle
in order to form the large load bearing surface 72 and guide
flanges 78 when lateral radius °RR" is substantially constant.
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The arc 84 corresponding to the large load bearing surface 72
preferably has a minimum radius of curvature "RR" of between
approximately five and one-half inches and approximately
fifteen inches along the surface 72. More preferably, the
minimum radius of curvature "RR" is within a range of
approximately eight and approximately fourteen inches. A most
preferred minimum radius of curvature "RR" is on the order of
about ten inches.
L0039~ Alternatively, lateral radius "RR" can vary
throughout some or all of the transverse curvature of radius
"rr". In such a situation, the minimum lateral radius "RR"
noted above will occur at only some locations, or perhaps only
one location, along the transverse radius "rr". In a typical
approach to providing a varying lateral curvature, the central
lateral radius "RR" will exhibit such minimum radius, as shown
in Fig. 8 and Fig. 13. The lateral radius "RR" at other
locations along the lateral curvature 80 will be greater than
the minimum radius.
I0040~ As an illustration of a varying lateral radius "RR",
at the locations where transverse diameter "D" intersects the
lateral surface of curvature 82, such as at 86 in Fig. 12, the
lateral radius "RR" is nominally infinite, with the lateral
curvature at this location approaching or reaching a straight
line. In this illustration, there is a gradual reduction in
the respective lateral radii "RR° values between the minimum
lateral radius location or radii locations and the straight-
line or approximate straight-line lateral radius or radii.
Thus, the value of lateral radius "RR" at intersections 90 is
greater than the value of the lateral radius "RR" at mid-point
intersection 88 and is less than the value of lateral radius
"RR" at diameter intersections 86. Substantially this same
pattern of lateral radius "RR" values variation can vary in a
gradually decreasing manner between intersections 90 and mid-
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point intersection 88 and in a gradually increasing manner
between intersections 90 and diameter intersections 80.
L0041] When a sufficient tensile force is applied to the
steel band 46, it will beneficially deform to match the
lateral curvature "RR" of the large load bearing surface 72,
which provides a "self-centering" function that prevents
lateral shifting of the steel band 46 and helps secure the
cargo. It will be seen that the radius of curvature of the
transverse radius "RR" is preferably greater than the radius
"R" of the prior art link, because an adequate "self-
centering" function is achieved, with less deformation of the
steel band 46 than with radius "R" of the link of Figs. 1-4.
L0042] In a preferred embodiment, the large load bearing
surface 72 preferably defines a symmetrical arc. For example,
Fig. 12 shows that the large load bearing surface 72 can
define an arc which extends above transverse diameter "D" and
is greater than 180Q and not more than 250-°, preferably
approximately 200°-. However, a greater or lesser arc angle
than that illustrated in Fig. 12 or a non-symmetrical curve or
arc are also contemplated by the present invention.
[0043] In a preferred embodiment, the top of cross
sectional area 76 (i.e. the two sloped surfaces closing the
area generally above transverse diameter "D") defines a
symmetrical 166°- angle. The exact shape of this portion is
not critical, because it does not engage the steel banding in
operation. As such, a complete cylindrical surface, such as
60 in Figs. 5 and 6 is unnecessary, because the steel band 46
will not engage much of the upper surface. Thus, a shape such
as that illustrated in Fig. 12 is preferred, because
unnecessary material is avoided without degrading performance.
[0044] Importantly, the improved link 70 is a unitary
structure. A link 70 according to the present invention may
be formed in a single drop forging step and there is no need
for later assembly of separate parts. Such an integral
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construction also provides a very durable link which is less
susceptible to breakage or unintended disassembly.
EXAMPLE
[0045] In a long-distance road test of about 1,000 miles
along a commercial rail route, a link according to the present
invention was compared to the prior art link of Figs. 1-4 and
the alternate retainer 22a which can be seen in Fig. 5. In
the road test, three flatcars with thirty-six attachment
points (i.e. eighteen steel bands) each were loaded with steel
pipe according to Vibration Isolation Connection requirements
of the American Association of Railroads (AAR).
[0046] The first flatcar used prior art links according to
Figs. 1-4, the second connected the steel bands directly to
the alternate retainers 22a illustrated in Fig. 5, and the
third flatcar used links according to the present invention.
It was found that two of the eighteen steel bands used with
each of the first two flatcars broke, whereas none of the
steel bands used with the third flatcar broke during the
entire length of this run.
(0047] It will be understood that the embodiments of the
present invention which have been described are illustrative
of some of the applications of the principles of the present
invention. Numerous modifications may be made by those
skilled in the art without departing from the true spirit and
scope of the invention, including those combinations of
features that are individually disclosed or claimed herein.
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