Patent ID: 8091724

Claim:
A container neck and closure assembly, wherein the container neck comprises a single piece of material including a substantially smooth outer surface and first screw thread formed in the internal surface of the single piece of material and the closure comprises a cylindrical plug for insertion into the container neck, said plug having a second screw thread on an outer surface thereof for engagement with the first screw thread wherein: the closure can be secured and resecured on the neck by a single smooth rotation through about 360° or less; the first screw thread is formed integrally with the container neck by moulding of thermoplastic material and comprises at least four first thread segments that do not overlap circumferentially around the container neck; the second screw thread comprises a plurality of second thread segments that are longer than said first thread segments and that define a continuous helical thread path along which the first thread segments travel from a fully disengaged to a fully secured position of the closure on the container neck; the first and second threads are multiple-start threads having a number of thread starts equal to the number of first thread segments; wherein the cylindrical plug on the closure and the container neck comprises complementary circumferential sealing surfaces below the threads, whereby the cylindrical plug forms a sealing interference fit with the neck below the threads when the closure is fully secured on the container neck; and wherein the container and closure further comprise complementary locking elements on the internal surface of the container neck and on the external surface of the closure that block or resist unscrewing of the closure from the fully secured position on the container neck until a predetermined minimum opening torque is applied.