| 摘要 |
<p>In a continuous screw conveyor or auger, the rotatable screw member (12) comprises a helical radial blade (28) (known as 'flighting') which is preferably carried on a central driving shaft (26). The flighting (28) is formed by rolling a rectangular metal strip of uniform thickness between a pair of opposed, preferably offset, conical rolls (56, 58). In contrast to prior art rolls which have similar unstepped conical rolling surfaces, and produce a helical blade of which the radial thickness reduce progressively from the inner helical edge (30) of the blade to the outer helical edge (32), the present invention provides on at least one of those rolls (58) a stepped conical rolling surface (94) formed so as to exert less rolling pressure on an outer portion of the helical blade (28) being formed, thereby to produce a blade in which the outer portion is of a thickness (preferably uniform) which is no less than and preferably greater than that of an inner part of the blade lying immediately radially inwards thereof.</p> |
