Container with a rim portion defining an opening, method and apparatus making said container

摘要

A method is provided for making a container having a body and a rim defining an opening for the container, the opening being capable of being closed by a push-on lid, the container being made of a material which is susceptible to deformation when heated.

主权项

1. A method of making a container having a body and a rim defining an opening for the container, the opening being capable of being closed by a push-on lid, the container being made of a material which is susceptible to deformation when heated, the method comprising the steps of:
a) providing a preform made of a material which is susceptible to deformation when heated, the preform being in the shape of a closed-end tube with a rim at its mouth, the rim comprising: an outward generally-radial flange having an upper surface and a lower surface, the flange extending from a radially inner end to a radially outer end, the tube depending from the radially inner end of the flange; a first detent simultaneously formed with the flange as an upstanding elongate projection from the upper surface of the flange, which detent is located at or near the radially inner end of the flange; and a second detent simultaneously formed with the flange as an upstanding elongate projection from the upper surface of the flange, which detent is located at or near the radially outer end of the flange; b) placing the preform in a pressure moulding apparatus at an elevated temperature with the preform being located in the apparatus at least in part by the second detent; c) expanding the tube under pressure to form the body of the container; and then d) moving the first detent in a controlled manner downwardly and outwardly relative to the second detent so that the first detent projects inwardly into the opening for the container; wherein the movement of the first detent downwardly and outwardly relative to the second detent occurs after the tube has been expanded, and is controlled such that after step d) the first detent projects inwardly into the container, with its elongate axis at an angle of from 60° to 120° to the elongate axis of the second detent, such that the first detent forms an internal rim.