Double ribbed cover

Abstract

A unitary closure is used with a tubular container having an open end with a cylindrical connecting bead at the open end. The unitary closure comprises a planar circular wall defining a flat upper surface having a peripheral edge. A first concentric ring is radially outwardly of the peripheral edge defining a first upwardly opening valley. A second concentric ring is radially outwardly of the first concentric ring at an annular peak and defines a second upwardly opening valley having a generally planar bottom wall. Inner and outer concentric ribs extend downwardly from the planar bottom wall. A connecting flange is radially outwardly of the second concentric ring including a downwardly opening channel receivable on the cylindrical connecting bead to close the open end of the container. The closure has a substantially greater wall thickness radially outwardly of the peak than radially inwardly of the peak.

I claim:  
     
         1 . A unitary closure for use with a tubular container having an open end with a cylindrical connecting bead at the open end, the unitary closure comprising: 
 a planar circular wall defining a flat upper surface having a peripheral edge, a first concentric ring radially outwardly of the peripheral edge defining a first upwardly opening valley, a second concentric ring radially outwardly of the first concentric ring at an annular peak and defining a second upwardly opening valley having a generally planar bottom wall, inner and outer concentric ribs extending downwardly from the planar bottom wall, and a connecting flange radially outwardly of the second concentric ring including a downwardly opening channel receivable on the cylindrical connecting bead to close the open end of the container, the closure having a substantially greater wall thickness radially outwardly of the peak than radially inwardly of the peak.    
     
     
         2 . The unitary closure of  claim 1  wherein the closure comprises a wall thickness nominally about 0.16 inches radially outwardly of the peak and a wall thickness nominally 0.09 inches radially inwardly of the peak.  
     
     
         3 . The unitary closure of  claim 1  wherein the circular wall and the first concentric ring have a first wall thickness, the second concentric ring, radially inwardly of the outer concentric rib has a second wall thickness greater than the first wall thickness and the outer concentric rib and the connecting flange have a third wall thickness greater than the second wall thickness.  
     
     
         4 . The unitary closure of  claim 1  wherein the closure having a wall thickness radially outwardly of the peak more than 50% greater then radially inwardly of the peak.  
     
     
         5 . The unitary closure of  claim 1  wherein the closure having a wall thickness radially outwardly of the peak about ⅔ greater then radially inwardly of the peak.  
     
     
         6 . A unitary closure for use with a tubular container having an open end with a cylindrical connecting bead at the open end, the unitary closure comprising: 
 a downwardly opening U-shaped wall portion receivable on the cylindrical connecting bead; a concentric ring inwardly of the U-shaped wall portion defining an upwardly opening valley including an outer wall connected to the U-shaped wall portion, a planar bottom wall and a conical inner wall having an upper annular edge; inner and outer concentric ribs extending downwardly from the planar bottom wall; and a circular center wall connected to the upper annular edge, the closure having a substantially greater wall thickness radially outwardly of the upper annular edge than radially inwardly of the upper annular edge.    
     
     
         7 . The unitary closure of  claim 6  wherein the closure comprises a wall thickness nominally about 0.16 inches radially outwardly of the upper annular edge and a wall thickness nominally 0.09 inches radially inwardly of the upper annular edge.  
     
     
         8 . The unitary closure of  claim 6  wherein the center wall has a first wall thickness, the concentric ring, radially inwardly of the outer concentric rib has a second wall thickness greater than the first wall thickness and the outer concentric rib and the U-shaped wall portion have a third wall thickness greater than the second wall thickness.  
     
     
         9 . The unitary closure of  claim 6  wherein the closure having a wall thickness radially outwardly of the upper annular edge more than 50% greater then radially inwardly of the upper annular edge.  
     
     
         10 . The unitary closure of  claim 6  wherein the closure having a wall thickness radially outwardly of the upper annular edge about ⅔ greater then radially inwardly of the upper annular edge.  
     
     
         11 . The unitary closure of  claim 6  wherein the center wall comprises a planar circular wall defining a flat upper surface having a peripheral edge and another concentric ring radially outwardly of the peripheral edge, defining another upwardly opening valley, and connected to the upper annular edge.  
     
     
         12 . The unitary closure of  claim 6  further comprising a pair of recessed bung wells connected to the center wall radially inwardly of the inner concentric rib.  
     
     
         13 . The unitary closure of  claim 6  wherein the U-shaped wall portion has a diameter to be received on a tubular container having a 21½ inch connecting bead.  
     
     
         14 . The unitary closure of  claim 6  wherein the closure comprises a unitary wall element of synthetic resin.