A common example of a core member
There are various structures directed toward increasing the strength of a joint between a connecting device and the members attached to it. For example, the practice of drilling through two items to be connected, then rivet bonding the items, is well known in the art. Yet, creating a joint single screw extruder by this method is both time-consuming and expensive. Similar joining methods include resistance spot welding and adhesive bonding. Many developments in the connecting device art have been directed toward lowering the cost of the devices, and decreasing the time and complexity of the joining process while simultaneously maintaining or increasing the strength characteristics, durability, and reliability of the joining devices and the ultimately formed joint.
Some of the core members of the prior art are used to connect members which protrude from the core at angles, in instances where the complete product cannot be directly manufactured in a single unit. A common example of a core member is the corner joint of a multipiece window frame structure, or the corner member of wall panels, or a central member of a furniture structure or scaffolding.
An exemplary area where the present invention is particularly applicable is in providing structural frame members for vehicles, such as automobiles, airplanes, railway cars, trucks and the like. For over the past decade there has been a thrust in vehicle manufacturing to reduce the overall weight of the vehicle sheet production extruder. In the automotive industry success has been attained not only through downsizing of the automobile, but also through the use of lightweight substitute materials, such as aluminum, in place of heavier materials, such as steel. Prior to 1973 what little aluminum was used in cars was typically employed for nonstructural applications. Today there is a significant increase in the aluminum usage primarily in structural applications, such as frames, bodies, drive trains and the like. Note for example U.S. Pat. No. 4,618,163 which pertains to an automobile chassis that includes extruded light metal rods.