Truck bed toolbox lid method of manufacture
An improved truck bed toolbox lid and a method of producing the same. The truck bed toolbox lid includes an outer metallic sheet layer comprising a generally rectangular top sheet member, a longitudinal front edge member, two lateral edge members and a longitudinal rear edge member. A metallic liner sheet member is disposed inside the top sheet member in edge contact abutment with beveled inside edges of the front and rear longitudinal edge members and the lateral edge members to create an internal cavity in which the liner is by stitch welding. One or more injection ports are provided through the liner sheet member through which a self-expanding and self-curing, relatively high-density, foam is injected. The stitch welded edge contacts leave non-welded, gas permeable junctions along the wedged cavity periphery at a funneled apex of the edge contacted boundary which facilitate expansion of the foam toward the outermost edges of the cavity.
1. A method for producing a truck bed toolbox lid comprising:
providing a metallic top sheet member having a depending front edge member, a depending rear edge member and depending lateral edge members, wherein an edge perimeter is formed along the depending front, rear and lateral edge members;
providing a substantially flat metallic liner sheet member;
joining said metallic liner sheet member to said metallic top sheet member in edge contact abutment with said edge perimeter so as to define an internal cavity having a funneled, gas permeable apex boundary; and
injecting a self-expanding, self-curing foam into said internal cavity in an amount such that said internal cavity is completely filled upon expansion of said foam, wherein said foam expands toward said funneled, gas permeable apex boundary and cures, such that said foam adheres to said metallic top sheet member and said metallic liner sheet member, and such that said metallic top sheet member, said foam and said metallic liner sheet member form a rigid composite member.
2. The method of claim 1 , further comprising applying a hot melt adhesive sealing member along the perimeter of said liner sheet member, such that upon cooling said hot melt adhesive sealing member forms a seal between the inside surface of said top sheet member and the outer edge perimeter of said liner sheet member to retain said foam within said internal cavity.
3. The method of claim 1 , further comprising heating said metallic top sheet member and said metallic liner sheet member during said injecting step.
4. The method of claim 1 , wherein said edge perimeter is beveled.
5. The method of claim 1 , wherein said joining step is performed by stitch welding said metallic liner sheet member to said beveled edge perimeter.
6. The method of claim 1 , wherein said joining step is performed by disposing said liner sheet generally parallel to said metallic top sheet member.
7. The method of claim 1 , wherein said metallic top sheet member is produced by cutting, folding and welding a single sheet of aluminum.