Positive orientation system for a threaded closure and container

A container and a non-removable closure assembly comprising:

• a container having a neck defining an opening to the container interior, an external screw thread, and a protuberance;
• said protuberance defining
• a) a leading abutment surface facing generally in a first direction of rotation in which said container neck thread screws into said closure thread, said leading abutment surface extending increasingly radially outwardly and increasingly axially closer to said opening with increasing circumferential distance around said neck in a second direction opposite to said first direction,
• b) a trailing abutment surface facing generally in the second direction of rotation, and
• c) a first cam surface extending between said leading and trailing abutment surfaces, said first cam surface extending increasingly radially outwardly and increasingly axially closer to said opening with increasing circumferential distance around said neck in said second direction;
• d) a second cam surface extending from said first cam surface in a direction away from said opening, said second cam surface extending between said leading and trailing abutment surfaces, said cam surface extending increasingly radially outwardly and increasingly axially closer to said opening with increasing circumferential distance around said neck in said second direction;
• a closure for being applied to said container neck and having a skirt defining an interior surface and a lower peripheral edge for engaging said first cam surface, said skirt defining an internal screw thread on said interior surface for engaging said external screw thread, said skirt further defining a recess in said interior surface and opening to said lower peripheral edge for receiving said container neck protuberance, said recess being defined on one end by a first engaging surface facing generally in a direction for engaging said leading abutment surface, said recess being defined on another end by a second engaging surface facing generally in a direction for engaging said trailing abutment surface, said recess being defined radially between said first and second engaging surfaces by a side surface, said side surface and said first engaging surface each extending increasingly radially outwardly and increasingly axially further from said lower peripheral edge with increasing circumferential distance around said closure in the direction toward said second engaging surface;
• and
• at least one of said skirt and neck being sufficiently resilient to deform as relative threading engagement is effected between said closure and said container neck to accommodate the relative movement of said protuberance and skirt interior surface until said protuberance is received in said recess, said skirt being sufficiently stiff to prevent relative rotation between said closure and container in either direction.