| 摘要 |
<p>In the manufacture of a ventilation fan, a rectangular steel strip (36) is stamped so that multiple rectangular cuts are made across most of its width and part way along its length. The cuts delineate three sides of what becomes a fan blade (24,25,...). The cut out section is then bent along a line perpendiulcar to the longer axis of the strip until it is at right angles to the strip. Alternate blades are bent upwards and downwards. Selected downward slots have a section bent to form rotor attachment lugs (31) when the strip is rolled into an annulus. The strip is fixed to the rotor of the motor by bolts passing through bent tabs.</p> |
