| 摘要 |
<p>The axial ventilation fan in which the number of blades can be varied without dismantling the rotor, has the roots of the blades retained in holes in the hub. The hub has a main shroud integral with the annular hub portion, and a shallower shroud portion which bolts onto the main portion, the bolts passing through the roots of the blades, and at the same time retaining a wedge block against each face of each blade root, fitting into a cylindrical hole for each root. The bolts can pass through slotted holes to permit play of the locking elements. In an alternative design, the wedge blocks can be shaped to permit an adjustment of the angle of the blade.</p> |
