| 摘要 |
<p>A window-frame (1) of a synthetic plastics material, being quite stiff and strong and, hence, specially suited to large-size windows, is provided with large-size rib formations (12) of hollow construction and having a substantially semicircular shape in cross-section, which are formed on the sides (2a-2d, 4a-4d, 5a-5d) of the wings (4,5) and the frame (2) of the window-frame (1), as well as with tubular stiffening inserts (14) of metal fitting into respective ones of said rib formations (12).</p> |
