Self-closing lid

Abstract

A self-closing lid that can be applied to a container and which provides a screen to prevent oversized debris from entering an inlet. The self-closing lid preferably includes a pair of flaps that rotate into an open position when material is being applied to the inlet and which rotate closed—preferably via a counterbalance, when material is no longer being applied to the inlet. The autonomous self-closing lid is preferably configured to not open in response to rainwater falling into the inlet and has shapes and/or features which direct the rainwater away from the inlet and outside of the lid.

What is claimed is: 
     
         1 . A self-closing lid comprising:
 a lid frame having an opening;   a pair of counterbalanced flaps, each of said pair of counterbalanced flaps hingedly coupled to said lid frame and positioned such that said pair of counterbalanced flaps are disposed on opposing sides of said opening such that said pair of counterbalanced flaps rotate between an open configuration and a closed configuration, wherein said pair of counterbalanced flaps are counterbalanced such that said pair of counterbalanced flaps are biased into a closed configuration due to counterbalancing; and   a screen positioned to screen material that passes through said opening.   
     
     
         2 . The self-closing lid of  claim 1  further comprising at least one water discharge opening disposed in said lid frame. 
     
     
         3 . The self-closing lid of  claim 1  wherein said pair of counterbalanced flaps are sized such that at least one of said pair of counterbalanced flaps comprises an end portion that overlaps an end portion of the other of said pair of counterbalanced flaps. 
     
     
         4 . The self-closing lid of  claim 1  wherein a portion of each of said pair of counterbalanced flaps passes through a respective opening in said frame. 
     
     
         5 . The self-closing lid of  claim 1  wherein said pair of counterbalanced flaps each comprise a counterbalance weight disposed thereon in a location that is outside of said lid frame. 
     
     
         6 . The self-closing lid of  claim 1  wherein said pair of counterbalanced flaps each comprise sidewalls that extend upward when said pair of counterbalanced flaps are in a closed configuration. 
     
     
         7 . The self-closing lid of  claim 1  wherein said pair of counterbalanced flaps are pitched when closed such that a terminal end portion of each respective flap is elevated higher with respect to a hinge location. 
     
     
         8 . The self-closing lid of  claim 1  wherein each of said pair of counterbalanced flaps are pitched to shed water to a first side and/or to a second side. 
     
     
         9 . The self-closing lid of  claim 1  wherein said screen is disposed within said opening in said lid frame. 
     
     
         10 . The self-closing lid of  claim 1  wherein said lid frame is hingedly coupled to a container. 
     
     
         11 . The self-closing lid of  claim 1  wherein said self-closing lid is configured to attach to a frac sand box. 
     
     
         12 . The self-closing lid of  claim 1  wherein said self-closing lid is disposed on a frac sand box. 
     
     
         13 . The self-closing lid of  claim 1  further comprising a mesh disposed above said opening of said lid frame. 
     
     
         14 . The self-closing lid of  claim 13  wherein said mesh is convex such that a center portion of said mesh is higher than an edge portion of said mesh. 
     
     
         15 . The self-closing lid of  claim 13  wherein said mesh is concave such that a center portion of said mesh is lower than an edge portion of said mesh. 
     
     
         16 . The self-closing lid of  claim 13  further comprising at least one wiper communicably coupled to at least one of said pair of counterbalanced flaps such that said at least one wiper moves across at least a portion of said mesh in response to movement by at least one of said pair of counterbalanced flaps. 
     
     
         17 . The self-closing lid of  claim 13  wherein said mesh is disposed within a mesh frame and wherein said mesh frame is movable with respect to said lid frame. 
     
     
         18 . A method for automatically opening and closing a lid in response to a material being applied thereto, the method comprising:
 forming an opening in a lid;   forming a frame around the opening;   counterbalancing a pair of flaps and positioning them such that the pair of flaps is biased into a closed position with respect to the formed opening when weight of material is not applied to them; and   positioning a screen above the pair of flaps.   
     
     
         19 . The method of  claim 18  further comprising hingedly coupling the lid to a container. 
     
     
         20 . The method of  claim 18  wherein hingedly coupling the lid to a container comprises hingedly coupling the lid to a frac sand box.