| 摘要 |
<p>The cover has a cover part (2) and a rear part (3), which are foldable together in an articulated manner, and a strengthening unit arranged at the point of articulation. The cover and rear parts are articulated along a folding line (5), and the strengthening unit is formed by strengthening elements (20), which are arranged on the cover and rear parts and leveled with two ends of the line. The strengthening elements are formed by separate parts or by portion of a sheet that is made of plastic material. The strengthening elements are brought back and fixed on the sheet by welding or bonding.</p> |
