| 摘要 |
<p>A mtal seal is formed from a blank, using a middle plate or lid and a projecting, peripheral edge section and a series of sheet metal forming operations. An upper and lower ledge are formed, the ledges being joined by a wall, and the outer edge of the lid is bent to form a first loose loop (1); an endless sepn. line is then scored in the lower ledge. The upper ledge and its adjacent wall are bent to form a second loose loop (2) followed by folding loop (1) so it butts against the lower ledge and forms a three-layer fold with a projecting nose. A tear-off tab is then fixed on the lid, the tab having a nose extending to the sepn. line, and loop (2) is folded to overlap the sepn. line and the tab. The seal is prf. ued for closing a container or can opened via a ter-off tab, where the human hand is shielded from the rough edge left on the can and the edge of the lid is smoothed over during its removal.</p> |
