| 摘要 |
<p>Service duct made of a synthetic thermoplastic material, comprising a rectangular section channel with a cover fitting the open side. The cover is made of the same material as the channel, is preferably flat and has lips which clip onto the edges of the channel. The side walls of the channel may have slits extending down in a perpendicular direction to the bottom. Both the channel and the cover have thin walls and transverse undulations, the thickness of the wall of both channel and cover being less than 1% of the width of the duct.</p> |
