Patent ID: 6015054
Filing Date: 2000-01-18
Classification: B65D

Abstract:
A container closure assembly comprising:a container neck having an opening;a closure for said neck, the closure having a crown portion and a skirt portion;a first screw thread on one of said neck and said closure, said first screw thread comprising one or more elongate first thread segments, each first thread segment having upper and lower first thread surfaces; anda substantially continuous second screw thread on the other of said neck and said closure, said second screw thread comprising one ore more elongate second thread segments, each second thread segment having upper and lower second thread surfaces, wherein the pitch of the lower second thread surface is relatively lower in a first region, relatively higher in a second region displaced from the first region in an unscrewing direction and relatively lower in a third region displaced from said second region in a unscrewing direction, and wherein said lower second thread surface further comprises a step adjacent to said third region to provide a first abutment surface against which a second abutment surface on one of said first screw segments abuts to block or restrict rotation of said closure in an unscrewing direction at an intermediate position when said closure is under axial pressure in a direction emerging from the container neck, said neck and closure being constructed and arranged to provide a vent for venting gas from said container neck at least when said closure is in said intermediate position, and said neck and closure being constructed and arranged to enable said step and said first screw segments to be moved out of engagement by axial displacement of the closure inwardly on said neck at said intermediate position, and wherein the lower second thread surface in said first region forms a matching fit with a major part of said upper first thread surface when the closure is fully secured in the container neck, and said third region forms a matching fit with a major part of said third region of said upper first thread surface when the closure is at said intermediate position and outwardly displaced on said container neck.