Circumferential ridge for a centrifugal fan

Abstract

An air impeller or circumferential fan includes one or more fan blades disposed between first and second plates. The first plate is tapered with respect to the second plate and includes an orifice that allows air to flow through the first plate and past the fan blades. The first plate also includes a circumferential ridge located away from the orifice which provides for more consistent construction of the first plate and, therefore, cheaper manufacturing of the air impeller.

What is claimed is:  
     
         1 . An air impeller comprising: 
 first and second plates;    an orifice disposed in the first plate adapted to allow air to flow through the first plate;    one or more fan blades disposed between the first and second plates; and    a circumferential ridge located on the first plate, wherein the circumferential ridge is located away from the orifice.    
     
     
         2 . The air impeller of  claim 1 , wherein the circumferential ridge is located along an outer rim of the first plate.  
     
     
         3 . The air impeller of  claim 1 , wherein the circumferential ridge is formed of the same material as the first plate.  
     
     
         4 . The air impeller of  claim 1 , wherein the first plate is radially tapered toward the second plate.  
     
     
         5 . The air impeller of  claim 1 , further comprising a shaft mounting hole disposed in one of the first and second plates.  
     
     
         6 . The air impeller of  claim 5 , wherein the shaft mounting hole is disposed in the second plate.  
     
     
         7 . The air impeller of  claim 1 , wherein the first plate includes an axial ridge forming the orifice.  
     
     
         8 . A vacuum cleaner comprising: 
 a housing;    a motor disposed in the housing;    an air impeller having a circumferential ridge and an orifice, wherein the circumferential ridge is located away from the orifice;    a shaft extending between the motor and the air impeller; and    a collection tank adapted to be connected to the housing.    
     
     
         9 . The vacuum cleaner of  claim 8 , wherein the air impeller further includes first and second plates.  
     
     
         10 . The vacuum cleaner of  claim 9 , wherein the circumferential ridge is located along an outer rim of the first plate.  
     
     
         11 . The vacuum cleaner of  claim 9 , wherein the circumferential ridge is formed of the same material as the first plate.  
     
     
         12 . The vacuum cleaner of  claim 9 , wherein the first plate is radially tapered toward the second plate.  
     
     
         13 . The vacuum cleaner of  claim 9 , further comprising a shaft mounting hole disposed in one of the first and second plates.  
     
     
         14 . The vacuum cleaner of  claim 13 , wherein the shaft mounting hole is disposed in the second plate.  
     
     
         15 . The vacuum cleaner of  claim 9 , wherein the first plate includes an orifice adapted to allow air to flow through the first plate.  
     
     
         16 . The vacuum cleaner of  claim 15 , wherein the first plate includes an axial ridge forming the orifice.  
     
     
         17 . The vacuum cleaner of  claim 8 , further comprising a hose connector adapted to direct air.  
     
     
         18 . A method of manufacturing an air impeller for a vacuum cleaner comprising the steps of: 
 forming a first plate having a circumferential ridge and having an orifice adapted to allow air to flow through the first plate, wherein the circumferential ridge is located away from the orifice;    forming a second plate; and    attaching at least one fan blade between the first and the second plates.    
     
     
         19 . The method of manufacturing an air impeller of  claim 18 , wherein the step of forming the first plate further includes the step of forming the circumferential ridge on an outside rim of the first plate.  
     
     
         20 . The method of manufacturing an air impeller of  claim 18 , wherein the step of forming the first plate further includes the step of forming the circumferential ridge of the same material as the first plate.  
     
     
         21 . The method of manufacturing an air impeller of  claim 18 , wherein the step of attaching at least one fan blade further includes the step of attaching at least one fan blade between the first and second plates so that the first plate is radially tapered toward the second plate.  
     
     
         22 . The method of manufacturing an air impeller of  claim 18 , further comprising the step of forming a shaft mounting hole in one of the first and second plates.  
     
     
         23 . The method of manufacturing an air impeller of  claim 22 , wherein the step of forming a shafting mounting hole further includes the step of forming the shaft mounting hole in the second plate.  
     
     
         24 . The method of manufacturing an air impeller of  claim 18 , wherein the step of forming the first plate further includes the step of forming an axial ridge in the first plate.