| 摘要 |
<p>In a composite section for making up window frames and the like, and comprising interengaging sections of metal and of plastics, there are at least two spaced-apart pairs of interengaging hook formations on the two sections, forced into tight engagement by the insertion of a wedging strip between the sections, the spacing apart of the formations ensuring stability against tilting. There are furthermore abutment surfaces on at least one of the hook formations on the plastics section and on the metal section to define accurately the relative positions of the sections. The purpose is primarily to ensure the front and back faces of the composite section are truly parallel and correctly spaced apart.</p> |
