| 摘要 |
1502002 Axial flow fans KARBERG & HENNEMANN KG 8 Aug 1975 [20 Aug 1974] 33152/75 Heading F1C An axial-flow fan impeller comprises blades 6 each having a blade root 8 which is mounted for securing in predetermined selectable positions in a bearing 14 provided on the impeller hub 2, contiguous peripheral surfaces 20, 22 of the blade root and bearing being provided with sets of semicylindrical notches a-i and A-O respectively, the angular intervals (e.g. 20 degrees and 22.5 degrees respectively) differing to give a vernier effect whereby various blade angles can be obtained by lining up a selected pair of notches (e.g. d and D as shown) and inserting a locking peg 18 into the pairs. The peg 18 is inserted through an opening 28 in a cover-plate 26 which is subsequently rotated about a screw 27 to a different position so as to retain the peg in place. Further notches for larger adjustment steps may be provided. |
