| 摘要 |
The neck portion, extending above the bead of a plastic drum, is provided with an in-bulging section adjacent its top, to form an annular bead of smaller diameter than the neck, and with a plurality of circumferentially spaced, out-bulging extensions, each of which has a lower surface slanting upward away from the neck. A tightly fitting cylindrical cover, which is not quite as long as the neck, and fits over the latter, has a recessed top and a lip-like reinforcement extending downward from the underside of the recessed top to form an annular groove of such width as to accommodate the bead on the neck of the drum. The cover has cut out portions through which the bulge-like extensions protrude and reinforcing extensions at the lower extremities of the remaining segments. These extensions have upper surfaces slanting away from the cover at such an angle that, with the lower surfaces of adjacent bulges on the neck, they define an acute angle. A spring steel locking ring engages these surfaces to draw the cover down tight about the neck and seal the drum. |
