A tamper evident closure for a threaded container

Abstract

A tamper evident closure ( 100 ) for containers having a threaded neck and a locking shoulder. The closure has a top ( 102 ) and an annular skirt ( 104 ) defining a cavity ( 105 ). The skirt has an upper portion ( 106 ) having threads ( 110 ) projecting into the cavity ( 105 ) for engaging the threaded neck, a lower portion ( 108 ) having a tuck ring ( 114 ), and a peripheral slit ( 112 ) between the upper portion and the lower portion. The peripheral slit ( 112 ) is interrupted by a plurality of hinge bridges ( 116 ), a plurality of pairs of sacrificial bridges ( 118 ) spaced from one another by a gap ( 120 ), and a plurality of vertical splits ( 124 ). One of each split ( 124 ) is in registration with a respective gap ( 120 ). The sacrificial bridges ( 118 ) and the tuck ring ( 114 ) break upon removal of the closure to divide the tuck ring into segments ( 126 ) between the vertical splits ( 124 ). The segments bend radially outward along the hinge bridges by a camming action on the locking shoulder on removal of the entire closure from the container.

1 . A tamper evident closure for containers having a threaded neck and a locking shoulder comprising:
 a shell of a ductile metal having a top and an annular skirt defining a cavity, the skirt having an upper portion having threads projecting into the cavity for engaging the threaded neck, a lower portion having a tuck ring, and a peripheral slit between the upper portion and the lower portion interrupted by a plurality of hinge bridges, a plurality of pairs of sacrificial bridges spaced from one another by a gap, and a plurality of vertical splits one of each in registration with a respective gap, the tuck ring being adapted to be turned under the shoulder for locking therewith, the sacrificial bridges and the tuck ring breaking upon removal of the closure to divide the tuck ring into segments between the vertical splits, the segments bend radially outward along the hinge bridges by a camming action on the locking shoulder on removal of the entire closure from the container.   
     
     
         2 . The closure of  claim 1  wherein the breaking of the sacrificial bridges and the vertical splits is accompanied by an audible sound of 50-70 db to indicate a first opening of the container. 
     
     
         3 . The closure of  claim 1  wherein the hinge bridges and the pairs of sacrificial bridges alternate about the periphery of the shell. 
     
     
         4 . The closure of  claim 1  wherein there are three hinge bridges, six sacrificial bridges, and three vertical splits. 
     
     
         5 . The closure of  claim 1  wherein the vertical splits are equally circumferentially spaced. 
     
     
         6 . The closure of  claim 1  wherein each hinge bridge of the plurality of hinge bridges is larger than each sacrificial bridge of the plurality of sacrificial bridges. 
     
     
         7 . The closure of  claim 1  further comprising a knurled pattern on an outer surface of the shell. 
     
     
         8 . The closure of  claim 1  wherein the ductile metal is an aluminum alloy. 
     
     
         9 . The closure of any  claim 8  wherein the aluminum alloy is EN AW-8011/A or EN AW-3105. 
     
     
         10 . The closure of  claim 1  wherein the closure has an opening torque with the container of from 3 lbf·in (3.44 kgf·cm) to 13 lbf·in (14.95 kgf·cm). 
     
     
         11 . The closure of  claim 1  wherein after the closure is removed from the container, a tuck ring segment requires at least six folds to separate the tuck ring from the closure. 
     
     
         12 . The closure of  claim 1  wherein the shell has a thickness of from 0.18 mm to 0.23 mm. 
     
     
         13 . The closure of  claim 1  wherein the hinge bridge has two segments separated by a third gap.