Stacking post top casting

Details Stacking post top casting Stacking post top casting

2000-03-10

2001-05-29

Pollard, Steven (Department: 3727)

Receptacles

Freight containers

Reexamination Certificate

active

06237794

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to stacking post top castings for cargo containers, and more specifically, to stacking post top castings adapted to allow for the top picking of such containers through a stacking post casting aperture located near the container outboard wall.
BACKGROUND OF THE INVENTION
Cargo containers are the standard and most popular means for shipping materials by trucks, trains, and ships. Typically, several lifting points are located on the exterior of the containers to facilitate handling. Uniform lifting points are typically used so as to allow vehicular cranes or marine cranes to load or unload cargo containers onto flat bed trucks, railroad cars, or ocean-going vessels.
To meet the high demands of economical shipping, manufacturers are increasing the size of the cargo containers to create more shipping capacity per container. Specifically, these modern containers are being made wider than the pre-existing containers. These wider containers locate the top casting aperture, used for stacking and lifting the container, a greater distance from outboard wall of the container. The effect of increasing the distance of the aperture from the outboard wall and increasing the size and weight of the container is substantially higher stresses on the stacking frame when the container is stacked or lifted. One solution introduced to reduce these stresses is to move the aperture closer toward the outboard wall. However, these top castings fail to provide adequate space and strength to allow the containers to be lifted by a top picking apparatus. A solution is needed, therefore, that provides a top casting that positions the aperture closer to the outboard wall of a container to reduce stresses caused by stacking and lifting, and that at the same time provides adequate space and strength to permit top lifting operations.
Cargo container lifting devices currently in use are typically shaped to be inserted into top castings at the lifting points on the cargo containers and can be turned or twisted in the top casting to be secured therein. These lifting devices are usually T-shaped and are presented in one angular setting to be received by conventional top castings. Each top casting provides an upwardly opening aperture for receiving the lifting device. Typically, after the lifting device is inserted into the aperture of the top casting, the lifting device is then rotated through 90° to a locking position. Once all lifting devices are locked to their respective top castings, the crane can begin lifting operations.
Standard cargo containers are manufactured in lengths of 10 feet, 20 feet, 30 feet, and 40 feet. Lifting points for these standard sized containers are generally located at or near the roof corners of the containers. The corner top castings have the benefit of two intersecting walls for support, namely the adjoining side wall and the end wall. In addition, the interconnection of a horizontal support between these top castings and a vertical post located at the intersection of the two walls aids in the structural integrity of the container.
Cargo containers also are manufactured in non-standard lengths in order to accommodate larger payloads while reducing associated shipping costs. These non-standard lengths are generally found in excess of 40 feet. Standard vehicular cranes and marine cranes must be capable of lifting such non-standard length containers. Therefore, lifting points are typically located or added at positions inboard from the ends of the containers. Lift fittings in the form of top castings are located at these lifting points. International standards require these top castings to be separated by 39 feet-4 inches center to center of the apertures.
Because the lifting points just described are located inboard from the ends of the container, a different support structure is required. These support frames are built into the structure of the containers. Although support frames are common for securing top castings, support frames do not provide as much support strength and rigidity as is available for the corner top castings on the standard length containers. Each support frame typically includes horizontal support members, vertical stacking posts, bottom castings and top castings. The upper horizontal support member extends between the side walls and is secured to the top castings. The lower horizontal support member extends between the side walls and is secured to the bottom castings. The vertical stacking posts support the side walls and couple respective top and bottom castings.
To facilitate secure and uniform stacking of cargo containers, bottom castings also include a downwardly opening aperture located from the outboard side a distance equal to the aperture of the top casting. International standards require 39 feet-4 inches between support frames and 89 inches between the apertures of each top casting set located a distance along the length of the cargo container. This standard spacing, along with the 40-foot standard spacing along the length of the container mentioned earlier, provides standard stacking points on cargo containers. These standards in turn allow for non-standard sized containers to be stacked with other containers. In order to lock stacked containers into place, IBC connectors are used between the top castings of a lower cargo container and the bottom castings of an upper cargo container. IBC connectors are container securement devices having upper and lower securing heads, similar to that of a top picking device. After the IBC connector head is located within the apertures of the top and bottom castings, the heads are rotated, locking the stacked cargo containers together. It should be noted that throughout the specification and claims herein, “connecting device” is defined as either a connecting device for an IBC connector or a connecting device for a top picker, or any other releasable engaging device used to connect the stacking post top casting via a top aperture to another conventional object or objects for stacking or lifting purposes.
Cargo containers have historically been manufactured to an exterior width that maintained the 89-inch separation between the apertures of the top castings to accommodate standard lifting devices. However, many more recent cargo containers have been manufactured with an increased width to increase cargo space. As a result, the top castings have become longer to maintain the coupling between the container side wall and the lift point of each top casting. In other words, the 89-inch distance between apertures of the top castings remains the same, but the distance between container side walls has increased, resulting in the need for longer top castings. Therefore, the distance between the aperture of each casting and the side wall of the container has increased.
Consequences of this increased distance are increased loads transferred to the stacking post and header during stacking and lifting operations. Because of the increased lateral spacing between these components, a longer moment arm subjects the stacking post to a larger torque loading. This type of loading has therefore introduced the necessity to provide additional strength to the support frames to withstand the loads imposed during stacking and lifting. Unfortunately, this increase in strength results in increased container weight, increased structural component size, decreased container capacity, and increased manufacturing costs.
One technique adopted to solve this problem, introduced by J. B. Hunt, is to position the aperture of each top casting closer to the outboard walls of the cargo container. For example, in a 102⅜ inch wide cargo container, the apertures are located 3.0″ from the outboard walls. This creates a distance of 96⅜ inches between corresponding top casting apertures, as opposed to the standard 89 inches of previous containers. This change in position decreases the length of the moment arm acting on the stacking post from the stacking forces transferred to the top casting at

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