IMPROVEMENTS RELATING TO CONTAINERS

摘要

A container is made in two stages from material such as thermoplastics that is deformable when heated. In the first stage a preform (1) is injection moulded, the mould parts easily releasing a tubular body (2) with a closed end and an outwardly projecting rim (3) at the open end. On or in the surface of the rim facing away from the body there is a formation such as a spiral rib (5) or groove. In the second stage the still heated preform (1) is blow moulded, possibly with some preliminary mechanical stretching, with the blow pin (9) seated in the open end of the body (2) and the preform held by the outer part (7) of its rim. The wall of the body (2) is expanded and the inner part (4) of the rim is urged away from the blow pin (9), deforming into a short tubular mouth with the formation (5) facing inwards. A spiral becomes a screw thread for receiving a screw-in cover.