| 摘要 |
<p>A flat blank, for example of cardboard, is cut out and fold lines are made on it. The upper edges of two opposed sides are stiffened by folding inwardly and gluing. There are three parallel fold lines and, when folded a triangular section results which cannot deform after gluing. The consequent opening in the top of the package is smaller than a section through the package. A transparent window, slightly domed for strength, is secured in the cover.</p> |
