Method and apparatus for making double wall containers

摘要

The individual structural member of the invention includes a pair of parallel panels which are spaced from each other to define a cavity therebetween. The panels are staggered in the longitudinal direction so that an end section of one panel extends beyond an end of the other panel and vice versa to form a front extension section and a rear extension section of the structural member. The non-extension end edge of each panel is connected to the opposing panel by a flat wall which is normal to the plane of both panels. Each extension section is provided with a flange. The front section flange of one structural member is adapted to interlock with the rear section flange of another structural member so that the structural members can be assembled in end to end fashion with the panels of one structural member being coplanar with the panels of adjoining structural members to form a double wall of, for example, a container.