| 摘要 |
<p>The method involves folding an inner sheath (3) which is made of front- and rear sides and upper- and lower sides. One of the sides is formed in a duplex manner, where an outer sheath (4) is folded on the inner sheath. The outer sheath is made of front- and rear sides. A lug is formed at each of the front- and rear sides of the outer sheath, which is folded against the inner sheath from front- and rear sides of the inner sheath.</p> |
