| 摘要 |
A plastic fan with several fins attached to a hub. The fins are formed in a mold in order to reduce the difference between themselves to a minimum. The fins are attached to the hub so that each of them is retained at an angle from the adjacent one. The fan so produced is well balanced during rotation. Each fin has a male engaging device which is engaged in a female engaging device formed in the hub. The fins are welded to the hub by ultrasonic waves.
|
