| 摘要 |
<p>PURPOSE:To prevent a lid from being blown off in an erroneous operation of the lid, by providing stepped primary and secondary stoppers for holding the lid within a range of a predetermined rotative angle of the lid at axially inside and outside portions. CONSTITUTION:An engagement portion 12 is formed with three engagement projections 51 extending circumferentially at equal pitch. Each of the engagement projections 51 is formed with a primary stopper 52 and a secondary stopper 53 which are continuous, and vertically deflected at its lower surface. On the other hand, an engagement portion 22 of a lid 2 is formed with three mating stoppers 55 extending circumferentially at equal pitch. In the event that the lid 2 is erroneously opened, the stoppers 55 are first moved rightwardly relative to the primary stoppers 52, and the lid 2 is upwardly moved by the pressure in a vessel 1. Accordingly, the stoppers 55 are allowed to collide with the secondary stoppers 53. Thus, the lid 2 is hindered from being further moved upwardly.</p> |
