Screw cap with setter and cover cap

摘要

The driver (29) of the twist cap (27) has a fitted spring arm which is co-rotatably held to the cap in the centre and is pre-tensioned at its free end to the top rim of the open-ended pot (6) acting as cap screw. The arm-forming leaf spring has two diametral sectors and the setter (14) exposed to steam content load forms a cylindrical piston which fills out the pot (6) and is sealed from this. The centre extension (18) of the setter reaches through an opening (13) in the base of the screw-forming pot (6), (4) and the setter is drilled out (20) and here closed by a valve (22) which opens with greater force than the spring arm (29). The pot acting as setting contains both valve (22) and its load spring (24). The spring arm engages a U-shaped metal holder which lies open to the spring arm and is secured to the plastics screw part (6, 4).