Tamper-evident seal for drum closure

Abstract

A molded, tamper-evident seal for a liquid container is formed with a flat end wall, a cylindrical side wall having a flared edge, and three detents spaced by 120 degrees from one another and extending inward from the side wall. Score lines extend from the edge of the side wall, and past one of the detents on both sides thereof, toward the end wall. An outwardly protruding pull tab is located between the score lines adjacent the edge of the side wall.

1 . A tamper-evident seal comprising a molded unit composed of plastics and having a substantially flat end wall with a circular perimeter, a side wall extending perpendicularly from the perimeter of the end wall and having a circular edge spaced from said end wall, the side wall having a substantially cylindrical inner face having a central axis, and a plurality of detents unitary with the side wall and protruding inwardly from said inner face for locking engagement with an overhanging rim on the closure of a fluid container, said detents being all of the inwardly protruding detents on said inner face, and one of the detents protruding inwardly from said substantially cylindrical inner face being circumferentially spaced from each of the other detents by an angle of at least 90 degrees measured along an arc centered on said central axis, a pull tab extending outward from said side wall, at a location adjacent said one of the detents, and a pair of score lines extending from the pull tab, past said one of the detents on opposite sides thereof, toward the end wall, said score lines weakening the side wall and permitting a strip, defined by an area of the side wall between said score lines and including said one of the detents, to be pulled away from the remainder of the side wall, thereby releasing the seal from the overhanging rim on the closure of the fluid container. 
   
   
       2 . A tamper-evident seal according to  claim 1 , in which said side wall has sufficient resilience that the seal can be engaged with the closure by causing said one of said detents to expand away from the other detents of a fluid container as the seal is pressed onto the closure and allowing said detents to snap into locking engagement with an overhanging rim on the closure. 
   
   
       3 . A tamper-evident seal according to  claim 2 , in which each of the detents is formed with a rim-engaging ramp extending obliquely from said inner face of the side wall toward the end wall. 
   
   
       4 . A tamper-evident seal according to  claim 2 , in which each of the detents is formed with a rim-engaging surface extending inward from said side wall in substantially parallel relationship to said end wall. 
   
   
       5 . A tamper-evident seal according to  claim 2 , in which each of the detents is formed with a rim-engaging ramp extending obliquely from said inner face of the side wall toward the end wall and a rim-engaging surface extending inward from said side wall in substantially parallel relationship to said end wall. 
   
   
       6 . A tamper-evident seal according to  claim 1 , in which said pull tab extends outward from said circular edge of the side wall. 
   
   
       7 . A tamper-evident seal according to  claim 1 , in which said score lines extend from the circular edge of the side wall to the end wall and across at least part of the end wall. 
   
   
       8 . A tamper-evident seal according to  claim 1 , in which said side wall is formed with an outward flare at said circular edge. 
   
   
       9 . A tamper-evident seal according to  claim 1 , in which said side wall is formed with a tapered outward flare at said circular edge. 
   
   
       10 . A tamper-evident seal according to  claim 1 , in which said detents protrude from said inner face of the side wall at a location spaced from said circular edge of the side wall. 
   
   
       11 . A tamper-evident seal according to  claim 1 , in which the number of detents on said side wall is three. 
   
   
       12 . A tamper-evident seal according to  claim 11 , in which said detents are substantially identical, and in which the detents are circumferentially positioned at intervals of approximately 120 degrees measured along an arc centered on said central axis.