| 摘要 |
<p>The mould casing (12) has sleeve inserts, and contains a core (14) one end side of which has a template (34) matching the shape of the channel in the base of the drainage shaft. The template has an outward protruding protuberance, which has an outer surface matching the wall of the channel at the bottom of the shaft. The protuberance has a first part leading at its base into the surfaces for the gradient of the base of the shaft. A second curved part of the protuberance is saddle-shaped to match the gradient of the channel base and is detachably joined to the first part, the template has a circular rim and radially inwardly displaced edge fitting into the hollow cylindrical core.</p> |
