Improvements in or relating to fans
908,586. Axial flow fans. WILMOTBREEDEN Ltd. April 12, 1961 [April 13, 1960], No. 13148/60. Class 110 (1). A fan has a hub portion formed with a hollow boss which receives the end of a shaft on which the fan is mounted and blades each having an integrally formed rib extending at least partway along the length of the blade and into the hub. The interior of the boss provides a location for a spigot on the fan shaft and fixing holes 14 are provided in the hub. The fan may be formed from one piece of sheet metal or from two or more pieces 15, 16 as shown in Fig. 3. Hollow bosses 17 on each member may nest together or the base of one boss may be removed as in Fig. 4. In a further embodiment, Fig. 5 (not shown), one piece has three blades and the other piece two blades, the blades being unequally spaced on assembly. Alternatively, the fan is again formed in two pieces, one piece having all the blades extending ' from a central portion and the other having tongues, which are spot welded to the blades, extending from a central portion. The former piece is formed with the hollow boss.