Adequate strength characteristics
This invention may be summarized as providing twin screw extruder comprising a longitudinally extending substantially hollow core and at least one longitudinally extending, hollow flange extending outwardly of and integral with a longitudinally extending side portion of the core. This invention also provides a joint wherein longitudinally extending lineal members have a hollow peripheral portion defined by walls having inside surfaces adapted to mate with outside surfaces of a mating hollow flange of the extruded node. In this joint the peripheral portion of the lineal member is mated with the hollow flange of the node, to an extent that the outer peripheral surface of the lineal member surrounds the integral wall of the node, and the outside surfaces of the sidewalls of the hollow flange and the inside surfaces of the lineal member mate along substantially the entire length and around the perimeter of the flange.
Among the advantages of single screw extruder is the provision of an extruded node which has adequate strength characteristics. Another advantage of the present invention is that the node may be utilized as a core member of a connection device which can be made to close dimensional tolerances by extrusion methods and still retain adequate ductility and strength characteristics.
A feature of the present invention is the provision of an extruded node having a substantially hollow core and hollow flanges. Advantages of the hollow structure are that the node weight may be reduced substantially when compared to most other nodes including certain cast nodes and solid nodes, and that structural support may be maintained in the node and in the joined structure.