| 摘要 |
<p>It comprises a metal section (1) which has its front face (2), a groove (3) and a ridge (4) close to its edge. A second section (5) is engaged in the metal section (1), with a hook-shaped lip (7) being fit into the groove (3), covering the ridge (4) and the edge of the front face (2). The second section (5) is provided with a flat wing (6), which is juxtaposed in the back of the front face (2) of the section (1). <IMAGE></p> |
