Dual taper fan-motor assembly

Abstract

A motor-driven fan assembly includes a bracket which couples to a motor assembly and includes an outlet port. A shroud assembly defines a chamber and includes an inlet port. The shroud assembly is received on a bracket and a bearing-supported shaft is driven by the motor assembly and extends through the bracket and into the shroud assembly. At least one fan is coupled to the shaft and received in the chamber. The fan includes a plurality of curved blades positioned between a frustoconical lower cap and an opposed frustoconical upper cap. Rotation of the fan by the shaft results in turbulent air flow through the fan assembly. Dust is generally prevented from settling on the fan blades during operation, thereby preventing non-uniform dust buildup or breakup which may cause excessive vibration and reduce bearing and brush life.

1 . A motor-driven fan assembly, comprising:
 a motor assembly;   a bracket coupled to said motor assembly, said bracket including an outlet port;   a shroud assembly which defines at least a chamber and includes an inlet port, said shroud assembly adapted to be secured to said bracket;   a shaft rotated by said motor assembly, said shaft extending through said bracket and into said shroud assembly; and   at least one fan coupled to said shaft and positioned in said chamber, wherein said at least one fan includes a plurality of curved blades positioned between an upper frustoconical cap and an opposed lower frustoconical cap, said at least one fan moving air from said inlet port to said outlet port.   
   
   
       2 . The fan assembly according to  claim 1 , wherein said blades are disposed between said caps in a curved sunburst arrangement radiating radially outwardly. 
   
   
       3 . The fan assembly according to  claim 1 , wherein said upper frustoconical cap further comprises a disc shaped base secured at its radial outer edge to a radial inner edge of said lower frustoconical cap. 
   
   
       4 . The fan assembly according to  claim 3 , wherein said base includes a central aperture adapted to receive said shaft therethrough. 
   
   
       5 . The fan assembly according to  claim 1 , wherein said upper frustoconical cap is substantially a mirror image in cross section of said lower frustoconical cap. 
   
   
       6 . The fan assembly according to  claim 5 , wherein said shroud assembly further comprises a first shell and a second shell, said first shell being secured to said second shell and said second shell secured to said bracket, a first chamber formed between said first shroud and said second shroud, and a second chamber formed between said second shroud and said bracket. 
   
   
       7 . The fan assembly according to  claim 6 , further comprising:
 a stationary fan disposed between said first chamber and said second chamber; and   a second fan constructed substantially the same as said first fan and coupled to said shaft and positioned in said second chamber.   
   
   
       8 . The fan assembly according to  claim 1 , wherein said upper frustoconical cap comprises an aperture extending therethrough and when said shaft rotates, air is drawn through said aperture and radially outward across said blades. 
   
   
       9 . A fan assembly, comprising:
 a shroud assembly that defines at least one chamber and includes an inlet port that communicates with said at least one chamber and an outlet port;   a bracket coupled to said shroud assembly, said bracket having an opening aligned with said outlet port, said bracket having an aperture therethrough and adapted to receive a rotatable shaft therethrough; and   at least one fan adapted to be coupled to the shaft and positioned in said at least one chamber, wherein rotation of the shaft causes air to be drawn into said inlet port and exhausted out said outlet port, and wherein said at least one fan includes a plurality of curved blades positioned between an angled upper cap and an opposed angled lower cap.   
   
   
       10 . The fan assembly according to  claim 9 , wherein each said blade is disposed between said caps in a curved sunburst arrangement radiating radially outwardly. 
   
   
       11 . The fan assembly according to  claim 9 , wherein said upper angled cap further includes a disc-shaped base secured at its radial outer edge to a radial inner edge of said lower angled cap. 
   
   
       12 . The fan assembly according to  claim 11 , wherein said base includes a central aperture adapted to receive the shaft therethrough. 
   
   
       13 . The fan assembly according to  claim 12 , wherein said upper angled cap is a mirror image in cross section of said lower angled cap. 
   
   
       14 . The fan assembly according to  claim 9 , wherein said shroud assembly further comprises a first shell and a second shell, said first shell being secured to said second shell and said second shell secured to said bracket, said first chamber being formed between said first shell and said second shell, said second chamber being formed between said second shell and said bracket, and wherein said fan assembly further comprises a second fan, substantially the same as said first fan, and adapted to be coupled to the shaft and received in said second chamber. 
   
   
       15 . The fan assembly according to  claim 14 , further comprising a stationary fan carried by said second shell and including a plurality of curved blades and a disc having a central bore, wherein air expelled by said first fan is directed by said stationary fan into said second fan.