Truck bed toolbox lid method of manufacture

Abstract

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. 
     
     
       8. 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;   providing a metallic liner sheet member;   joining said metallic liner sheet member to said metallic top sheet member to define an internal cavity; and   injecting a self-expanding, self-curing foam into said internal cavity 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 upon curing of said foam.   
     
     
       9. The method of claim 8, further comprising the step of sizing said metallic liner sheet member such that it is substantially coextensive with said metallic top sheet member. 
     
     
       10. The method of claim 9, further comprising the step of configuring said metallic liner sheet member such that it is planar. 
     
     
       11. The method of claim 10, wherein said joining step comprises disposing said metallic liner sheet member parallel to said metallic top sheet member. 
     
     
       12. The method of claim 8, further comprising the step of bracing said metallic liner sheet member prior to said injecting step, such that said metallic liner sheet member is prevented from flexing outward after injection of said foam. 
     
     
       13. The method of claim 8, further comprising the step of heating said metallic liner sheet member and said metallic top sheet member prior to said injecting step. 
     
     
       14. The method of claim 8, further comprising the step of heating said metallic liner sheet member and said metallic top sheet member during said injecting step. 
     
     
       15. 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;   providing a metallic liner sheet member;   joining said metallic liner sheet member to said metallic top sheet member to define an internal cavity; and   injecting a self-expanding, self-curing foam into said internal cavity such that said foam adheres to said metallic top sheet member and said metallic liner sheet member, and such that upon curing of said foam the rigidity of the combination of said metallic top sheet member and said metallic liner sheet member is increased.   
     
     
       16. The method of claim 15, further comprising the step of sizing said metallic liner sheet member such that it is substantially coextensive with said metallic top sheet member. 
     
     
       17. The method of claim 16, further comprising the step of configuring said metallic liner sheet member such that it is planar. 
     
     
       18. The method of claim 17, wherein said joining step comprises disposing said metallic liner sheet member parallel to said metallic top sheet member. 
     
     
       19. The method of claim 15, further comprising the step of bracing said metallic liner sheet member prior to said infecting step, such that said metallic liner sheet member is prevented from flexing outward after injection of said foam. 
     
     
       20. The method of claim 15, further comprising the step of heating said metallic liner sheet member and said metallic top sheet member. 
     
     
       21. A method for producing a truck bed toolbox lid comprising:
 providing a metallic top sheet member having depending edge members;   providing a substantially flat metallic liner sheet member;   joining said metallic liner sheet member to said metallic top sheet member in a manner which defines a cavity therebetween; and   injecting foam-forming material into said cavity such that foam formed thereby adheres to said metallic top sheet member and said metallic liner sheet member so as to form a strengthened composite member.   
     
     
       22. The method of claim 21, wherein sufficient foam-forming material is injected into said cavity such that the final product lid can be deflected in excess of four inches while remaining uncrimped, with no permanent set, when said lid is secured on a horizontal platform with approximately half the length of said lid extending beyond said platform and said lid is subjected to center pressure adjacent one of said depending edge members. 
     
     
       23. The method of claim 21, wherein sufficient foam-forming material is injected into said cavity such that the final product lid can be deflected to 7.5 inches while remaining uncrimped, with no permanent set, when said lid is secured on a horizontal platform with approximately half the length of said lid extending beyond said platform and said lid is subjected to corner pressure adjacent one of said depending edge members. 
     
     
       24. A method for producing a truck bed toolbox comprising:
 forming a lid by steps including
 providing a metallic top sheet member having depending edge members; 
 providing a substantially flat metallic liner sheet member; 
 joining said metallic liner sheet member to said metallic top sheet member in a manner which defines a cavity therebetween; and 
 injecting foam-forming material into said cavity such that foam formed thereby adheres to said metallic top sheet member and said metallic liner sheet member so as to form a strengthened composite member; 
   providing a generally rectangular, generally tub-shaped, open-topped lower receptacle;   joining the lid to the lower receptacle in a manner which permits the lid to pivot upwardly to expose the interior of the lower receptacle.   
     
     
       25. The method of claim 24, wherein sufficient foam-forming material is injected into said cavity such that the lid can be deflected in excess of four inches while remaining uncrimped, with no permanent set, when said lid, before being joined to the lower receptacle, is secured on a horizontal platform with approximately half the length of said lid extending beyond said platform and said lid is subjected to center pressure adjacent one of said depending edge members. 
     
     
       26. The method of claim 24, wherein sufficient foam-forming material is injected into said cavity such that the lid can be deflected to 7.5 inches while remaining uncrimped, with no permanent set, when said lid, before being joined to the lower receptacle, is secured on a horizontal platform with approximately half the length of said lid extending beyond said platform and said lid is subjected to corner pressure adjacent one of said depending edge members. 
     
     
       27. The method of claim 24, wherein said metallic liner sheet member is joined to said metallic top sheet member at a plurality of discrete locations with gaps therebetween through which gas can escape. 
     
     
       28. The method of claim 27, wherein said metallic liner sheet member is joined to said metallic top sheet member by welding. 
     
     
       29. The method of claim 28, wherein said metallic liner sheet member is joined to said metallic top sheet member by stitch welding. 
     
     
       30. The method of claim 24, wherein the metallic top sheet member is 0.063 inch thick.