| 摘要 |
A tamper-evident buttress plug for sealing closed a plastic 55-gallon drum includes a plug body which is externally threaded and compatible with the internally threaded container outlet, a ratchet ring which includes a circumferentially distributed series of ratchet teeth on its inner surface and a series of four frangible elements which initially integrally join the ratchet ring to the plug body. The container outlet has neck which is configured with two spaced series of ratchet teeth which are of a size and configuration so as to be mutually engageable with the ratchet teeth on the closure ring. As the closure is threadedly advanced into the outlet, threaded engagement is first achieved and then ratchet engagement. When it is time for the closure to be removed from the container, the frangible elements must be severed so as to separate the ring and the plug body. In view of the fact that the 55-gallon plastic drum is blow-molded by split-block technique, it is necessary for the two series of ratchet teeth on the container outlet to be less than 180.degree. in their circumferential extent thus leaving spaces between the series. In order to prevent compression of the ring by squeezing inwardly at the location of these two spaces, semi-circular raised protuberances are provided in order to prevent ovalizing and an ability to disengage the ratchet teeth. |
