Composite cargo door/ramp

Abstract

A cargo enclosure including a floor having a plurality of edges including a first edge, a second edge and a third edge. At least two sidewalls, including a first sidewall and a second sidewall, the first sidewall, connected to the first edge of the floor, the second sidewall connected to the second edge of the floor. At least one hinge is connected along the third edge of the floor, the at least one hinge being rotatable about an axis. A composite door is connected to the at least one hinge, the door having a closed position and the hinge having a plurality of torsion springs rotatable about the axis, the plurality of torsion springs biasing the composite door toward the closed position.

1 . A cargo enclosure comprising: 
 a floor having a plurality of edges including first, second and third edges;    a first sidewall coupled to said first edge and a second sidewall coupled to said second edge;    a door having an edge disposed along said third edge of said floor, said door having an open and a closed position; and    at least one torsion spring coupled to said edge of said door and to said third edge of said floor, said at least one torsion spring providing a biasing force that comprises a substantial proportion of the force needed to move said door from said open position to said closed position.    
   
   
       2 . The cargo enclosure of  claim 1 , wherein said biasing force of said at least one torsion spring is sufficient to maintain said door in said closed position.  
   
   
       3 . The cargo enclosure of  claim 1 , wherein the weight of said door when said door is moved toward said open position overcomes said biasing force of said at least one torsion spring.  
   
   
       4 . A cargo enclosure comprising: 
 a floor;    a plurality of sidewalls coupled to, and disposed orthogonal to, said floor;    a door coupled to said floor via at least one hinge for allowing said door to move between a closed position, wherein said door is disposed orthogonal to said floor and to said plurality of sidewalls, and an open position, wherein said door forms an obtuse angle with respect to said floor; and    at least one torsion spring coupled to said floor and to said door, said at least one torsion spring exerting a biasing force that biases said door toward said closed position such that said biasing force is insufficient to overcome the weight of said door when said door is in said open position yet sufficient to aid in easily moving said door from said open position to said closed position.    
   
   
       5 . A material container for over the road use comprising: 
 a container floor disposed above ground level;    a door having a first edge coupled to said floor via at least one hinge, and a second edge remote from said first edge, said hinge allowing movement of said door between a closed position wherein said door is substantially perpendicular to said container floor and an open position wherein said second edge extends to and contacts said ground level thereby forming a ramp from said ground level to said container floor; and    at least one torsion spring coupled to said door and to said container floor, said at least one torsion spring providing a biasing force that comprises a substantial proportion of the force needed to move said door from said open position to said closed position.    
   
   
       6 . The material container of  claim 5 , wherein the biasing force of said at least one torsion spring is sufficient to maintain said door in said closed position.  
   
   
       7 . The material container of  claim 5 , wherein the weight of said door when said door is moved toward said open position overcomes the biasing force of said at least one torsion spring.