Tamper-Evident Screw Closure for Containers and Bottles, Especially for Plastic Bottles

Abstract

A plastic tamper-evident screw closure is disclosed for containers and bottles. An exemplary tamper-evident screw closure includes a screw cap, which has a cylindrical jacket with an internal thread, and an annular tamper-evident strip which is connected to a free edge of the jacket by breaking webs or the like and is equipped with locking elements. The tamper-evident strip can have a smaller outside diameter than the jacket of the screw cap. The locking elements can be configured as undercut regions in the tamper-evident strip which in each case run between two adjacent breaking webs as a ring segment, and extend from a cylindrical inner wall to an outer wall of the tamper-evident strip.

1 . Tamper-evident screw closure of plastic comprising:
 a screw cap which has a cylindrical jacket with an internal thread;   a ring-shaped tamper-evident strip which is connected via breakaway webs or the like to a free edge of the jacket; and   locking elements configured for positive engagement with an abutment of a container or bottle,   wherein the tamper-evident strip has an outside diameter which is smaller than that of the jacket of the screw cap and wherein the locking elements are formed by bevelled undercut regions of the tamper-evident strip which each run as a ring segment between two adjacent breakaway webs and which extend from an axially longer cylindrical inside wall to an axially shorter outside wall of the tamper-evident strip.   
   
   
       2 . Tamper-evident screw closure as claimed in  claim 1 , wherein the tamper-evident strip has a wall thickness which is 40% to 80% of the wall thickness of the cylindrical jacket of the screw cap in a thread-free region. 
   
   
       3 . Tamper-evident screw closure as claimed in  claim 1 , wherein each beveled undercut region of the tamper-evident strip has an axial length which is ⅓ to ⅔ of an axial length of the breakaway webs. 
   
   
       4 . Tamper-evident screw closure as claimed in  claim 1 , wherein each undercut region with the inside wall of the tamper-evident strip forms a largely sharp-edged transition. 
   
   
       5 . Tamper-evident screw closure as claimed in  claim 1 , wherein the breakaway webs have an axial length which is 50% to 100% of an axial length of the outside wall of the tamper-evident strip adjoining the undercut regions. 
   
   
       6 . Tamper-evident screw closure as claimed in  claim 1 , wherein an axial length of the breakaway webs is such that an annular gap between the screw cap and the tamper-evident strip has a width from roughly 0.5 mm to roughly 5 mm. 
   
   
       7 . Tamper-evident screw closure as claimed in  claim 1 , wherein an inside diameter of the tamper-evident strip measured over the undercut regions is larger than an inside diameter of the screw cap measured over on the internal thread sections. 
   
   
       8 . Tamper-evident screw closure as claimed in  claim 1 , wherein the undercut regions which each run as a ring segment between the breakaway webs have a peripheral extension which corresponds to 60% to 100% of a distance measured in a peripheral direction between two adjacent lengthwise edges of two adjacent breakaway webs. 
   
   
       9 . Container in combination with a tamper-evident screw closure as claimed in  claim 1 . 
   
   
       10 . Container as claimed in  claim 9 , comprising:
 a region of a neck of the container in which the tamper-evident strip is located when the tamper-evident screw closure has been screwed on the container, wherein the region has a longer axial extension than that of the tamper-evident strip.   
   
   
       11 . Tamper-evident screw closure as claimed in  claim 2 , wherein each beveled undercut region of the tamper-evident strip has an axial length which is ⅓ to ⅔ of an axial length of the breakaway webs. 
   
   
       12 . Tamper-evident screw closure as claimed in  claim 11 , wherein each undercut region with the inside wall of the tamper-evident strip forms a largely sharp-edged transition. 
   
   
       13 . Tamper-evident screw closure as claimed in  claim 12 , wherein the breakaway webs have an axial length which is 50% to 100% of an axial length of the outside wall of the tamper-evident strip adjoining the undercut regions. 
   
   
       14 . Tamper-evident screw closure as claims in  claim 13 , wherein the axial length of the breakaway webs is such that an annular gap between the screw cap and the tamper-evident strip has a width from roughly 0.5 mm to roughly 5 mm. 
   
   
       15 . Tamper-evident screw closure as claimed in  claim 14 , wherein an inside diameter of the tamper-evident strip measured over the undercut regions is larger than an inside diameter of the screw cap measured over on the internal thread sections. 
   
   
       16 . Tamper-evident screw closure as claimed in  claim 15 , wherein the undercut regions which each run as a ring segment between the breakaway webs have a peripheral extension which corresponds to 60% to 100% of a distance measured in a peripheral direction between two adjacent lengthwise edges of two adjacent breakaway webs. 
   
   
       17 . Container in combination with a tamper-evident screw closure as claimed in  claim 16 . 
   
   
       18 . Container as claimed in  claim 17 , wherein the container is a plastic bottle.