| 摘要 |
<p>A metallic wall (20) having coined knockouts (24, 26). The wall includes a first surface (32) and a second surface (34) spaced from the first surface. A plurality of spaced knockout portions (24, 26) are positioned in incipient apertures in the wall and are disposed substantially between the surfaces (32, 34). Each knockout portion (24, 26) is defined by a first indentation (72) encompassing the knockout portion and extending from the first surface (68), and by a second indentation (74) encompassing the knockout portion and extending from the second surface (70). These indentations (72, 74) are in alignment with a web of material (78) of substantially uniform thickness throughout its length spacing the indentations. The outside surface defining the first indentation (72) is inclined inwardly. A coating is applied to the second surface (70) after formation of the indentations (72, 74). A sharp blow to the knockout portion from the second surface (70) fractures the web (78) to allow removal of the knockout portion without any material of the wall extending substantially beyond the first surface (68).</p> |
