| 摘要 |
<p>Mfr. is claimed of a helicoidal fan blade with the section of an aerofoil. This is extended by a part forming a solid of revolution for jaw fixing on to a wheel hub. Article is obtd. by casting in a metal mould a mixt. which following its polymerisation, liberates a gaseous fluid to form a sponge structure. In contact with the mould a skin is formed, thick enough to form a shell resistant to tension, torsion, and bending caused by the blade in action. The solid of revolution is made before insertion in the mould.</p> |
