Patent Application
20070257094
The present invention relates generally to containers for retaining and protecting goods during shipment and methods for making such containers. In particular, the present invention relates to a continuously wound reinforced shipping container.
Corrugated fiberboard containers have been used for many years as shipping and storage containers for a large variety of products. Corrugated fiberboard generally refers to a multi-layer sheet material comprised of sheets of liner bonded to central corrugated layers of medium. Single-wall corrugated involves two sheets of liner bonded on alternate sides of one corrugated medium, while double-wall corrugated involves three liners bonded alternatively to two corrugated mediums. Corrugated fiberboard containers can vary greatly in size depending on the intended usage of the container.
The distribution of products in large containers is common in a wide variety of industries, from automotive to food. Corrugated semi-bulk containers (“CBCs”) serve as an example common in the meat industry for storing and shipping beef, pork, and other animal products between processing facilities, and from those processing facilities to customers. CBCs often require local horizontal zones of additional reinforcement for containment, to prevent container failure and ensure products are saleable when they arrive at the end of the distribution process and any auxiliary processes. Reinforcement methods are often used on CBCs and other corrugated containers in order to increase the performance more cost-effectively (by localizing the region of peak performance) than by switching to some other container material or increasing the overall strength of the corrugated component of the CBC.
Internal reinforcement of corrugated board can include polymeric straps located between one of the sheets of liner and one of the mediums to further enhance the bulge or tear resistance of the structure, increasing the performance of the overall container. However, even when polymeric straps are included within the corrugated board structure, a weak spot will occur at the manufacturing joint, which is the area of overlap of the fiberboard sheet when a container is formed. Because the corrugated board is discontinuous at this joint, the internal reinforcement is also discontinuous, creating a failure nucleation zone at the joint. This weakness is typically overcome by using external reinforcement in conjunction with or in lieu of internal reinforcement.
External reinforcement is most often accomplished by the use of multiple horizontal bands of strapping material. These external reinforcing straps may be placed on the container when it is in a flat semi-assembled orientation before being formed into a typically shaped container (“knocked down”) or may be applied after the container has been formed into its final typical shape (“set-up”). Previous reinforcing straps have been made from metallic materials or polymeric materials. The reinforcing straps are formed onto a set-up CBC or around a knocked down CBC in a continuous loop, with the two ends of the strapping material typically attached together using methods common in the industry. Metallic straps may be crimped together, while polymeric straps may be heat welded together.
Frequently, reinforcing straps are applied so that the spacing between two adjacent straps is generally equal around the periphery of the container, whether they are applied to containers in a knocked down or set up configuration, i.e. the straps are typically parallel. The reinforcing straps are spaced some distance apart along the height of the container. When straps are applied to a container in a set up configuration, the reinforcing straps are typically applied one-at-a-time by one or more individuals. The process of adding reinforcing straps to the container in a set up configuration often results in large variations in strap placement and strap tightness when comparing several containers, with an associated variation in strap impact on overall container performance.
Reinforcing straps applied to containers while the containers are in a knocked down orientation typically are applied in a semi-automated process. In the semi-automated mode one automatic strapper is used to apply straps. One or more individuals moves the knocked down CBC through the strapper manually, with the external straps applied at predetermined locations. While this process only requires one strapping machine, it is quite slow and requires significant manual labor. Strap placement accuracy depends on the patience and attention of the operators. This process can be automated (intermittent motion) on a conveyor, by having the CBC stop at fixed locations relative to the individual strapper, so that the external straps are applied at the specified locations. It can be further automated by using one strapping machine for every band/strap placed on the box (frequently 3 or more). Not only does this require extensive capital expense but also a dedicated manufacturing line. Initial strap placement is typically controlled to within roughly one-to-two strap widths of the target location, depending on the mechanism by which the knocked down CBC is started and stopped on the manufacturing line.
Reinforcing straps currently used are individually joined continuous loops that are not physically attached to the container so as to prevent movement or sliding of the bands. They rely on the tension of the strapping material as well as friction to stay in place. If the tension is high, the strap will remain precisely where placed at the risk of also deforming or damaging the CBC, potentially decreasing container performance. Typically, tension levels are set to avoid significantly damaging the container while allowing the strap to remain in an intended location by friction. When strap tension level is low, bands often slip from their intended locations when the containers are put into use, increasing the likelihood of lower container performance.
Additionally, reinforcement straps currently used typically have a much higher elongation at failure compared to the corrugated fiberboard material used to make the containers. Corrugated fiberboard typically has an elongation at failure of about between one and a half percent and two percent (1.5%-2%). Many polymeric reinforcement straps used currently have an elongation at failure of about fifteen percent (15%). This near order of magnitude difference of elongation at failure requires that the strapping material used be selected so that it has the necessary strength to reinforce the container at the elongation of failure of the corrugated fiberboard, to ensure that the straps help prevent the failure of the fiberboard, not simply help to contain the contents of the container after the fiberboard fails. This is important as some customers will not accept the contents of a container if the container has been breached. Using a material in a reinforcing strap that has the required strength at the elongation at failure of the corrugated material typically requires that a much stronger material be used, as most materials have their greatest strength just prior to failure. Thus, the majority of the strength of the reinforcing strap goes unused.
Thus, it would be desirable to use a reinforcement material that is physically attached to the container, and which further is made of one continuous piece to allow for quicker application. It would be further desirable to use a reinforcing material with a more similar elongation at failure than that typically used currently for container reinforcement.
According to one embodiment of the present invention, a reinforced container assembly comprises a fiberboard container and a first reinforcement strap. The fiberboard container has a lower portion and an upper portion. The first reinforcement strap wraps continuously around a periphery of the container a plurality of times in a generally spiraling manner from a starting point of the reinforcement strap to a terminating point of the reinforcement strap. The first reinforcement strap is physically connected to the container at a first location. The first reinforcement strap is further physically connected to the container at second location The first reinforcement strap provides structural support to the fiberboard container to increase the strength of the container assembly.
According to one process of the present invention a method of reinforcing a fiberboard container is provided. The process provides a fiberboard container that has a lower portion and an upper portion. Additionally, a first reinforcement strap that has a first end and a second end is provided. The first reinforcement strap physically attaches to the container at a first position. The reinforcement strap wraps around a periphery of the container a plurality of times in a generally spiraling pattern. The first reinforcement strap physically attaches to the container at a second position such that a vertical spacing exists between the first position and the second position when the container is in a set-up configuration.
According to another process of the present invention, a method of reinforcing a fiberboard container is provided. The method provides a corrugated fiberboard container that has internal polymeric reinforcing straps. The container has a lower portion and an upper portion. A first fiberglass reinforced adhesive tape reinforcement strap is additionally provided. A first location of the first reinforcement strap physically attaches to the container at a first position. The reinforcement strap wraps around a periphery of the container a plurality of times in a generally spiraling pattern from the lower portion of the container to the upper portion of the container. The first reinforcement strap physically attaches to the container during the act of wrapping. A second location of the first reinforcement strap physically attaches to the container at a second position.
According to another embodiment of the present invention, a reinforced container assembly comprises a fiberboard container and a first reinforcement strap. The fiberboard container has a lower portion, an upper portion, and a sidewall outer surface area. The first reinforcement strap wraps continuously around a periphery of the container a plurality of times. At least a first wrap of the first reinforcement strap occurs in a first generally identical vertical location of the container before the wraps form a generally spiraling pattern. The first reinforcement strap physically connects to the container at a first location at a first position of the first reinforcement strap. The first reinforcement strap further physically connects to the container at a second location at a second position of the first reinforcement strap. The reinforcement strap provides structural support to the fiberboard container to increase the strength of the container assembly. Wherein, the distance between each of the plurality of wraps in the generally spiraling pattern of the first reinforcement strap around the periphery of the container is greater than a width of the first reinforcement strap.
Other advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings in which:
While the invention is susceptible to various modifications and alternative forms, a specific embodiment thereof has been shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that it is not intended to limit the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.
Turning now to
The reinforcement strap 14 is manufactured from a material with less than five times the elongation at failure as the fiberboard used to form the container 12. Thus, for example, if the fiberboard has an elongation at failure of two percent (2%) the reinforcement strap would have an elongation at failure of less than ten percent (10%) at the time of application. Non-limiting examples of materials that may be utilized for the reinforcement strap include reinforced packaging tape, adhesive tape, polymeric film, and stretch polymeric string. The polymeric film and the stretch polymeric string may be pre-stretched, such that the polymeric material has already been elongated a certain amount prior to being wrapped around the container 12.
According to one embodiment, the reinforcement strap 14 is physically attached to the container 12 in at least two locations. The reinforcement strap 14 may physically attach to the container at the beginning of the strap 16 and the end of the strap 18, or the reinforcement strap 14 may physically attach to the container 12 in at least two locations between the beginning of the strap 16 and the end of the strap 18. The reinforcement strap 14 may be continuously attached along its length to the container 12. Attaching the reinforcement strap 14 to the container 12 continuously assures that the location of the reinforcing strap 14 will not change as the reinforced shipping container assembly 10 is transported.
Additionally, attaching the reinforcement strap 14 continuously along its length further enhances the ability of the reinforcement strap 14 to retain the structural integrity of the container 12, as both the strength of the container 12 and the reinforcement strap 14 must be overcome to rupture the container assembly 10. Therefore, a continuously applied reinforcement strap 14 provides a greater amount of reinforcement to the container 12 than currently used systems.
Further, attaching the reinforcement strap 14 continuously around the periphery of the container assembly 10 significantly reinforces the manufacturing joint, improving the strength of the manufacturing joint of the container that arises a discontinuity in any internal reinforcement of the manufacturing joint.
According to one embodiment of the present invention, the reinforcement strap 14 is a reinforced adhesive tape. Using a reinforced adhesive tape for the reinforcement strap 14 allows the reinforcement strap 14 to be continuously attached to the container 12. One example of a reinforced tape is a fiberglass reinforced pressure sensitive tape. The fiberglass reinforced pressure sensitive tape has an elongation at failure of approximately three percent (3%).
Referring still to
Similarly, it is contemplated that according to an alternate embodiment, the vertical spacing between each wrap of a reinforcement strap may decrease moving from a lower portion of a container to an upper portion of the container, thereby providing additional reinforcement to the upper portion of the container.
As shown in
The number of wraps of the reinforcement strap 14 may vary based on the application of the container 12 and the desired strength of the reinforced shipping container assembly 10. Typically a reinforcement strap is wound around a container between three and ten times. Five wraps of the reinforcement strap 14 are depicted in
As shown in
Turning next to
It is further contemplated that the spacing of a reinforcement strap may be completely variable based on a particular application of the container assembly. For example, it is contemplated that the spacing between wraps may be less at a middle portion of the container assembly relative to a top and bottom portion of the container assembly to provide additional reinforcement at a predetermined portion of the container assembly. Further, according to another example, the spacing between wraps of the reinforcing strap may be small at a bottom portion of a container assembly, large at a middle portion of a container assembly, and small at a top portion of a container assembly based on a particular application of the container assembly.
Turning now to
The relative rates of movement of the horizontal arm 114 about the vertical support 112 and the turntable 110 rotational speed determine the distance between wraps of the reinforcing strap 120. For example, if a complete overlap is desired for a particular reinforcing wrap, the horizontal arm 114 remains stationary on the vertical support 112 as the container 118 completes one revolution on the turntable 110. To increase the spacing between wraps of the reinforcing strap 120 the horizontal arm 114 move up the vertical support at a faster rate as the container 118 rotates on the turntable 110. To decrease the spacing between wraps of the reinforcing strap 120 the horizontal arm 114 move up the vertical support 112 at a slower rate as the container 118 rotates on the turntable 110. Alternately, the horizontal arm 114 may move up the vertical support 112 at a constant rate while the turntable 110 rotates to create uniform spacing between the wraps of the reinforcing strap 120. Thus, the distance between wraps of the reinforcing strap 120 may be optimized for each particular application of a container.
Additionally, as the reinforcing strap is physically attached to the container, the number of wraps may include a partial wrap, so as to provide a more exact amount of reinforcement to a container assembly for a particular application.
It is further contemplated that a continuously wound reinforcing strap may be applied to a container in a knocked down position, as shown in
While the present invention has been described with reference to one or more particular embodiments, those skilled in the art will recognize that many changes may be made thereto without departing from the spirit and scope of the present invention. Each of these embodiments and obvious variations thereof is contemplated as falling within the spirit and scope of the claimed invention, which is set forth in the following claims.
