| 摘要 |
The scroll wrap portion of a centrifugal blower housing is joined to the opposite scroll side portions thereof using uniquely configured double tab locking joints spaced apart around the peripheries of the scroll side portions. To form the joints, spaced series of tabs formed along the curved side edges of the scroll wrap are extended outwardly through corresponding peripheral slots in the scroll sides, and are brought into side-by-side adjacency with outwardly projecting tabs formed on the scroll sides at their peripheral slots. Supported series of forming tools positioned outwardly of the opposite scroll sides are forced inwardly against the side-by-side tab pairs in a manner tightly rolling them together to simultaneously form all of the double tab locking joints around both of the scroll side peripheries. The rolled joints mutually interlock portions of each of the scroll sides with adjacent portions of the scroll warp in a manner essentially preventing any appreciably relative movement between the scroll wrap and side portions at their joined areas.
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