A large number of different container structures are utilized by manufacturers to ship a variety of different products to end users, which may be, for example, assembly plants. In the automobile industry, for example, an assembly plant assembling a particular automobile might utilize a number of different parts from different manufacturers. These manufacturers ship their respective parts to the assembly plant in containers in which the parts are then removed from dunnage hanging from movable dunnage supports inside the container and assembled into a finished automobile.
Access to the product in the containers is of particular concern. Specifically, in the automotive industry, the containers full of product are positioned on an assembly line adjacent to a work area which is associated with a particular product to be installed on a manufactured vehicle. For example, a container full of parts is usually positioned next to a particular station on an assembly line where the parts are installed so that a line worker may easily access the parts inside the container. The product or part is taken directly from the container and used on the line. Some existing containers are difficult to access, which makes removal of the parts therein difficult and time-consuming. For example, some containers are configured so that a line worker must walk around the container to remove parts or products from opposite ends of the container. As may be appreciated, a line worker only has a certain amount of time to install a part. Any delay in access and removal of the part from the container is undesirable.
In many containers, a line worker or employee must insert or remove parts from a distal or rear part of the container. The size and/or weight of the parts or work pieces may cause stress or strain on the line worker and, more particularly, on the back of the worker when inserting or removing parts from such a container. Such ergonomically unfriendly movements may cause physical trauma, pain and other injuries that may lead to lost production time.
In some situations, in order to alleviate such stress and/or strain on his or her body, the line worker may move to the rear or opposite end of the container to remove parts from inside the container. This requires space around the container which may not be available, depending on the physical layout of the plant or facility. The length (front to back) of certain containers may be limited because the container manufacturer needs to eliminate the need for a line worker to walk around the container to remove product from inside the container. Such containers having a reduced length reduce the number of parts or products which may be shipped and/or stored in the container. The more containers needed to ship a predetermined number of parts, the greater the cost to the shipper.
In some containers having multiple layers or level of parts, a line worker or employee must lean forward and bend down into the container to insert or remove a part or work piece from the bottom of the container. This movement by the line worker is ergonomically unfriendly because the line worker must lean forward and bend down into the container to insert or remove a part or work piece from the bottom of the container.
Depending upon the number of times the line worker repeats this unnatural motion, strain in the back, legs and arms may result. The size and/or weight of the parts or work pieces may increase the strain on the line worker. Thus, simply removing multiple parts during a work day may cause physical trauma, pain and other injuries that may lead to lost production time. Consequently, returnable and reusable containers having multiple levels of movable dunnage, such as the container disclosed in U.S. Pat. No. 8,308,015, have been used.
In known containers having multiple levels or layers of dunnage, such as pouches, a pocket may be sewn at the upper edges of each side of each pouch and sized to receive a dunnage support, such as a rod or a tube, for example. The dunnage support may have rollers or end members secured to opposed ends of a middle member. The end members move in tracks secured to the sides of the container. The end members may add cost to the assembled container and present an opportunity for failure due to fatigue/wear. Therefore, a unitary metal tube or dunnage support may be desirable in some applications.
One difficulty with using unitary metal dunnage supports and metal rails is that friction between the metal rails and the metal dunnage supports may damage one or more of the metal rails and/or one or more of the metal dunnage supports after repeated movements of the dunnage supports. In addition, the amount of force necessary to move the dunnage supports along the rails may be greater than desired. Spall may be created and make the dunnage supports difficult to move.
Accordingly, there is a need for a returnable and reusable shipping container which has one or more layers of movable dunnage supports supporting dunnage and requires less effort to move the dunnage supports extending between metal rails than heretofore.
There is further a need for a returnable and reusable shipping container having multiple levels of movable dunnage therein which may be assembled with unitary dunnage supports and may have an increased life compared to heretofore known containers.