Structural sandwich plate members

Abstract

A structural sandwich plate member comprises first and second outer plates and a core material of plastics or polymer material. A plurality of lightweight forms are disposed between the outer plates so that the core material forms ribs extending in two substantially orthogonal directions. The lightweight forms may be hollow or solid and manufactured out of foam, plastics or expanded polystyrene. The structural sandwich plate member is preferably formed by injecting the plastics or polymer core material into a closed cavity formed between the outer plates and in which the lightweight forms have been preplaced.

1 . A structural sandwich plate member comprising: 
 first and second outer plates formed of metal;    a core of substantially compact plastics or polymer material bonded to said outer plates with sufficient strength to transfer shear forces therebetween; and    a plurality of relatively lightweight forms disposed within said core;    wherein said lightweight forms are disposed so that there are ribs of said plastics or polymer material extending in two substantially orthogonal directions in the plane of said plate member, said ribs also extending between said first and second outer plates.    
   
   
       2 . A structural sandwich plate member according to  claim 1  and having a rectilinear shape, wherein said two substantially orthogonal directions are substantially parallel to the edges of said structural sandwich plate member.  
   
   
       3 . A structural sandwich plate member according to  claim 1  and having a substantially rectilinear shape, wherein said substantially orthogonal directions form an acute angle to the edges of said structural sandwich plate member.  
   
   
       4 . A structural sandwich plate member according to  claim 1 ,  2  or  3  wherein the spacing between ribs extending in a first of said two substantially orthogonal directions is greater than the spacing between ribs extending in a second of said two substantially orthogonal directions.  
   
   
       5 . A structural sandwich plate member according to  claim 1 , wherein the spacing between ribs extending in said first of said two substantially orthogonal directions is in the range of from about 0.5 to about 2 m.  
   
   
       6 . A structural sandwich plate member according to  claim 1 , wherein the thickness of said ribs is in the range of about 10 to about 100 mm.  
   
   
       7 . A structural sandwich plate member according to  claim 1 , wherein said ribs extend substantially uninterrupted from one edge of said structural sandwich plate member to another.  
   
   
       8 . A structural sandwich plate member according to  claim 1 , wherein said ribs span between said first and second outer plates.  
   
   
       9 . A structural sandwich plate member according to  claim 1 , wherein said ribs have been formed by injection of said plastics or polymer material into a space defined between said first and second plates.  
   
   
       10 . A method of manufacturing a structural sandwich plate member comprising the steps of: 
 providing first and second outer plates formed of metal in a spaced-apart relationship with a plurality of lightweight forms located therebetween;    injecting uncured plastics or polymer material to fill the space defined between said outer plates and said lightweight forms; and    allowing said plastics or polymer material to cure to form a substantially compact material that bonds said outer plates together with sufficient strength to transfer shear forces therebetween;    wherein said lightweight forms are disposed so that said plastics or polymer material forms ribs extending in two substantially orthogonal directions in the plane of said plate member.    
   
   
       11 . (canceled)  
   
   
       12 . (canceled)