| 摘要 |
PCT No. PCT/GB82/00073 Sec. 371 Date Sep. 30, 1982 Sec. 102(e) Date Sep. 30, 1982 PCT Filed Mar. 5, 1982 PCT Pub. No. WO82/03059 PCT Pub. Date Sep. 16, 1982.In a combination of a screw-threaded metal closure cap with a container having an externally screw-threaded neck, of the type in which the closure thread is formed by a thread rolling operation in a blank in situ on the container, one or more interruptions are made in the closure thread to provide a pressure leakage path, through which gas can blow off in the interval between unsealing the container and the release of the closure from the container thread. Complementary notches may be formed in the container thread. The interruptions in the closure thread are conveniently provided by forming the thread by means of a thread roller having one or more notches in its periphery.
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