1. Field of the Invention
This invention is generally directed to systems for transporting, storing and supporting cargo containers of the type utilized in local and long distance shipping and warehousing of bulk goods or freight and more particularly to such a system which incorporates support frames which are interlockable with the shipping containers and which serve to support the shipping containers when unloaded from a transporting vehicle such as a flat bed truck, trailer, water vessel or railroad car. In one embodiment of the present invention, the frames are designed to be self-elevating with respect to the transporting vehicle so that the frames may be raised and lowered in order to permit a plurality of legs associated with the frames to be extended horizontally and then vertically to support the containers above the bed of the transporting vehicle. After elevation, the vehicles may be simply driven from under the frames and containers. Thus, the containers are loaded or unloaded without the need of supplemental elevating equipment such as hoists, cranes or forklifts.
In the preferred embodiments of the present invention, the frames are interlocked with alignment cradles which are mounted to a transport vehicle. In alternate embodiments, the cradles may be carried by lift assemblies so that the cradles serve to elevate the support frames and shipping containers relative to the transporting vehicle.
In yet other embodiments of the present invention, specialized trailers may be incorporated which further include pneumatic or hydraulic leveling devices for insuring that the load beds of the vehicles are retained in a horizontal position during loading and unloading of the support frames.
2. History of the Related Art
Due to the cost associated with shipping goods not only locally but long distance, including internationally, and due to the need to standardize the manner in which freight is warehoused or shipped, many goods are transported in large metallic shipping containers. The shipping containers are conventionally loaded and unloaded with respect to a transport vehicle by the use of forklifts or cranes which raise and lower the containers relative to the supporting deck or bed of the transporting vehicle. Unfortunately, such systems require that loading and unloading equipment be available at each point at which a container is to be loaded or unloaded from a transporting vehicle. This limits the available points of delivery or pickup for the goods being shipped or requires that the transporting vehicle be retained in an area where goods are to be loaded or unloaded thereby increasing shipping cost by requiring the vehicle to be retained in a fixed location for often lengthy periods of time. By way of example, if a shipping container is to be loaded with household goods for an individual moving from one area to another, it is conventionally necessary for a truck having a trailer to remain at the point of loading until the shipping container is loaded. During this period of time, the motor vehicle and trailer are not being used for their primary purpose of hauling freight from one location to another. This radically increases the cost of shipping.
In order to overcome the deficiencies with respect to such conventional shipping techniques, shipping systems have been developed which allow shipping containers to be unloaded from the transporting vehicle at a point of delivery or at a point of loading until the container is ready for further shipment. In U.S. Pat. No. 3,817,413 a de-mountable load carrying body for a vehicle is disclosed which includes a container or body which is supported by longitudinal rails mounted to the vehicle. The container or body is rollable with respect to the vehicle frame and includes vertically positionable legs which support the body when it is rolled from the frame. Unfortunately, this type of transport system requires specialized vehicles and specialized containers which will allow the container to be rolled relative to the frame of the vehicle. In addition, this type of system requires that the demountable load carrying body be exactly aligned with the vehicle both vertically and horizontally during loading and unloading, which in a practical sense, would rarely be possible.
Another example of a detachable truck bed or body is disclosed in U.S. Pat. No. 4,076,299 to Dalton. This patent discloses a truck bed which is elevated from the frame of a truck by the use of hydraulic cylinders. After the bed has been raised a plurality of legs are lowered into engagement with the ground thereby stabilizing the bed relative to the truck frame. The truck is thereafter driven from under the truck bed. Unfortunately, with this type of system, it is necessary to provide the hydraulic cylinders to the truck frame in order to enable the lifting of the truck bed and thus the truck bed could not be utilized as a support frame on conventional shipping vehicles including railway flat cars or flat bed trucks. In addition, the patent does not provide for a precise alignment between the removable truck bed and the truck frame.
Another type of container transport system is disclosed in U.S. Pat. No. 4,053,073 to Franchin. In this system, the containers which are to be transported by motor vehicle are provided with hydraulic cylinder lifts at each corner of the container. In this manner when it is desired to elevate the container from the truck bed, the cylinders are activated and the container is raised. Unfortunately, with this type of system, the cylinders also function as the support legs for the container. Therefore, extremely large hydraulic cylinders must be provided so as to enable the containers to be lifted from a trailer bed of conventional height which may be a height of approximately 51" or more. Thereafter, the fluid cylinders must support the weight of the cargo container for extended periods of time. Also, such a system does not allow for any maneuvering space between the vehicle bed and the container. Such a system would be highly impractical and expense.
In U.S. Pat. No. 3,995,760 to Burgdorf et al., a motor vehicle container transport and support system is disclosed wherein the containers are supported on frames which are detachably mounted to a cradle mounted to a vehicle bed such as the bed of a tractor trailer. This patent discloses that the cradle provides a means for aligning the main support frame with respect to the vehicle during loading and unloading. The patent further discloses the use of an interlock system for securing the containers to the frame. When it is desired to release the frame from a motor vehicle, the legs of the frame are first extended outwardly, in outrigger fashion, with respect to the frame and then the legs lowered vertically. Once the legs are in contact with the ground the vehicle may be moved allowing a sliding motion to be established between the main frame and the support frame. Unfortunately, this type of sliding between the main frame and the cradle is not practical and a great deal of stress is imparted to the support legs during loading and unloading of the frame with respect to the transport vehicle. With this system, the frame for supporting the shipping container is locked to the cradle by locking mechanisms similar to that provided for locking the container to the main frame. This requires separate activation of a plurality of locking mechanisms to secure the main frame to the cradle.
Some additional examples of prior art systems are disclosed in U.S. Pat. Nos. 2,478,578 to Gottshall, 3,119,503 to Herpich et al., 3,152,709 to Fowler, 3,722,948 to Walsh et al., 3,724,697 to Arvidsson, 4,000,924 to Blasingame, 4,089,539 to Berger, and 4,339,148 to Smith et al.