Lading tie anchor link with enhanced banding contact surface

A two-piece anchor assembly has a retainer and an interlocking link. The link is a unitary component that is formed by a single forging step. The link is secured to the floor of a railway flatcar by the retainer. A steel band is connected at one end to a load bearing surface of the link of a first anchor assembly and at another end to a load bearing surface of the link of a second anchor assembly. A tensile force is then applied to the steel banding and crimped with a clip in order to secure cargo. The load bearing surface has an enhanced banding radius, which reduces the risk of band breakage when the steel band is subjected to a high tensile force by preventing “creasing” at contact locations.

BACKGROUND OF THE INVENTION

1. Field of the Invention

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.

2. Description of Related Art

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 crimp seal typically is applied to maintain an appropriate tension level during transport.

Many types of anchor assemblies are well-known. The “Flexi” anchor assembly made by Ireco LLC is an example of a known device.FIGS. 1-4illustrate a device20according to the two-piece “Flexi” anchor assembly. The “Flexi” assembly20comprises a steel retainer22which is affixed to the floor or frame24of a flatcar and a steel link26which is movably connected to the retainer22. The arcuate retainer22takes the form of an inverted “U” which can be welded to the floor or frame24of the flatcar. The link26is triangular and defines a generally triangular central aperture28which interlocks the retainer22. The anchor assembly20is configured such that the retainer22passes through the central aperture28of the link26and effectively hooks the link26to a floor surface or a frame area24of the flatcar.

One side30of the link26includes a banding portion32, while the end34defined by the intersection of the other two sides36engages the retainer22.FIGS. 1 and 2show that the banding portion32includes a lateral convex curvature surface38facing the central aperture28. This part of the banding portion32has a radius of curvature “R” of approximately five inches.FIGS. 3 and 4show that the cross section40of the retainer-engaging end34is circular, while the cross section42of the banding portion32approximates a rectangle with curved corners. The two corners44nearest the central aperture28have a 0.25 inch radius of curvature “r”.

In use, a securing means, such as a steel band46, is passed through the aperture28of the link26, so as to engage the banding portion32. Banding surface38is sufficiently wide to accept a 1.25 inch or 2 inch steel band. When tension is applied to the steel band46, it tightens against the banding portion32and deforms in part to take the shape of the lateral convex curvature surface38.FIG. 2shows in broken lines that the link26is free to take an angled orientation when the steel band46engages the banding surface38.FIG. 2also shows in broken lines the use of a cable or wire48extending from an end of the link between two sides30and36.

The steel band46engages a portion of the cross-sectional perimeter of the banding portion32of the link26, best shown in broken lines inFIG. 3. The surface of the banding portion32along the link26generally conforms to the opposing, parallel surfaces50of the link26and the lower surface52. The magnitude of the curvature of the steel band46about the banding portion32is referred to herein as the banding radius “r”. It can be seen that the banding radius “r” inFIG. 3varies due to the irregular shape of the banding portion32. The lower curved corners44each subject the steel band46to a relatively sharp curve, which can result in creasing of the steel band46.FIG. 3also shows the link26flat against the floor surface24of the flatcar, in a stored position when it is not in use.

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.

We have determined that the banding radius of anchor assemblies as illustrated inFIGS. 1-4is inadequate, especially when used to secure top-heavy or uneven loads, such 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.

FIGS. 5 and 6illustrate examples of previous attempts to solve these band breakage problems. As shown, both anchors56and58provide a right cylindrical element60having a larger banding portion than that illustrated inFIGS. 1-4, while also providing an increased banding radius. The cylindrical element60is separate from the link body62and mounted thereto by a bolt64, which is itself secured to the link body62by a threaded nut66.

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 element60ofFIGS. 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 and eventually failure at heavier loads. Accordingly, the anchor assemblies ofFIGS. 5 and 6attempt to decrease band breakage by providing a larger banding portion and right cylindrical banding radius. The anchor assemblies ofFIGS. 5 and 6are relatively expensive because they require several components (i.e. a cylinder, a bolt, and a nut) to achieve their goal.

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.

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.

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.

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

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 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.

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 inFIGS. 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 theFIGS. 5 and 6links, while achieving performance characteristics at least as advantageous as those ofFIGS. 5or6.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 7shows an anchor assembly68having an improved link70according to the present invention. The anchor assembly68includes the retainer22ofFIG. 1, which interlocks the improved link70according to the above description of the prior art anchor assembly20. The improved link70functions to receive metal banding in the general sense of the prior art link26ofFIG. 1. However, as perhaps best illustrated inFIG. 9A, the large load bearing surface72of link70is larger than the banding portion32and allows for a greater banding radius “rr”. Preferably, the surface72has 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. 9Ashows that the large load bearing surface72has a cross-sectional area76which is substantially larger than the nominal cross-sectional area40of the link70at other points, such as at the retainer-engaging end34. In contrast,FIG. 4shows that the cross-sectional area42of the banding portion32of the prior art link26is comparable to the cross-sectional area40at the retainer-engaging end34.

FIG. 9Ashows that the large load bearing surface72approximates a smooth arc along radius “rr”, whereas the banding portion32illustrated inFIG. 3is more U-shaped and creates isolated zones44with small banding radii “r”. Accordingly, due to the improved link70of the present invention, the tensile stress in the steel band46is 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, 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.

In an alternate embodiment, the improved link70can include two guide flanges78which are shown disposed along the sides of the large load bearing surface72. The flanges78extend beyond or flank the large load bearing surface72, as best shown inFIGS. 10 and 10A, and guide the steel band46when it is first applied to the link26, by preventing it from moving laterally beyond the bounds of the large load bearing surface72.

As shown inFIG. 9A, in the stored position, the guide flanges78can be useful in preventing the large load bearing surface72from coming into contact with the floor surface24of the flatcar. Accordingly, the flanges78can assist in having the large load bearing surface72remain cleaner than when flanges are omitted and allow a true fit for the steel band46, when engaged. Also, unlike prior art links which will freeze to the railway car deck or frame under winter conditions, flanges78minimize 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.

The improved link70may include a lateral, convex curvature80along the large load bearing surface72, in which event the curvature80will have a minimum radius “RR”. Radius “RR” can be substantially constant throughout the transverse curvature of radius “rr”.FIG. 13shows the shape of a surface82which may be rotated through an obtuse angle in order to form the large load bearing surface72and guide flanges78when lateral radius “RR” is substantially constant. The arc84corresponding to the large load bearing surface72preferably has a minimum radius of curvature “RR” of between approximately five and one-half inches and approximately fifteen inches along the surface72. 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.

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 inFIG. 8andFIG. 13. The lateral radius “RR” at other locations along the lateral curvature80will be greater than the minimum radius.

As an illustration of a varying lateral radius “RR”, at the locations where transverse diameter “D” intersects the lateral surface of curvature82, such as at86inFIG. 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 intersections90is greater than the value of the lateral radius “RR” at mid-point intersection88and is less than the value of lateral radius “RR” at diameter intersections86. Substantially this same pattern of lateral radius “RR” values variation can vary in a gradually decreasing manner between intersections90and mid-point intersection88and in a gradually increasing manner between intersections90and diameter intersections80.

When a sufficient tensile force is applied to the steel band46, it will beneficially deform to match the lateral curvature “RR” of the large load bearing surface72, which provides a “self-centering” function that prevents lateral shifting of the steel band46and 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 band46than with radius “R” of the link ofFIGS. 1-4.

In a preferred embodiment, the large load bearing surface72preferably defines a symmetrical arc. For example,FIG. 12shows that the large load bearing surface72can define an arc which extends above transverse diameter “D” and is greater than 180° and not more than 250°, preferably approximately 200°. However, a greater or lesser arc angle than that illustrated inFIG. 12or a non-symmetrical curve or arc are also contemplated by the present invention.

In a preferred embodiment, the top of cross sectional area76(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 as60inFIGS. 5 and 6is unnecessary, because the steel band46will not engage much of the upper surface. Thus, a shape such as that illustrated inFIG. 12is preferred, because unnecessary material is avoided without degrading performance.

Importantly, the improved link70is a unitary structure. A link70according 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 construction also provides a very durable link which is less susceptible to breakage or unintended disassembly.

EXAMPLE

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 ofFIGS. 1-4and the alternate retainer22awhich can be seen inFIG. 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).

The first flatcar used prior art links according toFIGS. 1-4, the second connected the steel bands directly to the alternate retainers22aillustrated inFIG. 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.

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.