| 摘要 |
<p>A frame for in situ assembly, comprising two jambs and a head extending perpendicularly to the jambs, the jambs and the head consisting substantially of metal section strips forming a channel, the section strips having their opening facing outwards for gripping the edges of a wall, while means are provided for fastening the head to the jambs, wherein at least the sides of the jambs gripping the wall extend upwards substantially throughout the height of the sides of the head, so that the head is as it were disposed between the two jambs, while the width of the head is smaller than the width of each of the jambs and the fastening of the narrower head between the jambs is such that the head recedes relative to the jambs at the front and at the back. <IMAGE></p> |
