| 摘要 |
<p>The rim is of profiled plate, and the parallel portions of the two parts overlap for a specific amount near the base of a groove accommodating a sealing strip. One or both of the parts (4, 5) have bosses (11) pressed out from them at regular intervals, by means of which they are spot-welded to each other. The contact surfaces (10) of the bosses can have further protrusions formed in each of them, preferably in the centre. On the vertical portions of the parts every third boss can be secured to the other one, and on the horizontal ones every second one. The contact surfaces of the bosses can be approximately 2 mm proud of the base of the groove.</p> |
