Suspension type heat-dissipation fan

Abstract

A suspension type heat-dissipation fan includes a frame rotatably supporting an air impeller therein. The frame has an air outlet and is formed with an inner rim defining an opening aligned with the air impeller. In addition, a ring is attached to the rim of the frame and has an inner periphery defining an air inlet of a size smaller than the diameter of the air impeller. This inventive fan increases the pressure of airflow into the air inlet, while enabling the air impeller to be placed into the frame through the opening before assembling the ring to the rim.

What is claimed is:  
     
         1 . A suspension type heat-dissipation fan comprising: 
 a frame rotatably supporting an air impeller therein, said fame having an air outlet and being formed with an inner rim defining an opening aligned with said air impeller; and    a ring attached to said rim of said frame, said ring having an inner periphery defining an air inlet of a size smaller than the maximum diameter of said air impeller.    
     
     
         2 . The suspension type heat-dissipation fan as claimed in  claim 1 , wherein said ring has an outer periphery defining an annular groove, and wherein said inner rim of said frame is adapted to be snapped into said annular groove of said ring.  
     
     
         3 . The suspension type heat-dissipation fan as claimed in  claim 1 , wherein said inner rim of said frame is stepped so as to define a countersunk opening, and wherein said ring is attached to said inner rim by means of adhesive.  
     
     
         4 . The suspension type heat-dissipation fan as claimed in  claim 1 , wherein said ring has an inclined end surface sloping towards said air impeller from a radially outer portion thereof to a radially inner portion thereof for leading air into said air inlet.  
     
     
         5 . The suspension type heat-dissipation fan as claimed in  claim 4 , wherein said inclined end surface of said ring is configured as a curved surface.  
     
     
         6 . The suspension type heat-dissipation fan as claimed in  claim 3 , wherein said ring has a uniform thickness.  
     
     
         7 . The suspension type heat-dissipation fan as claimed in  claim 6 , wherein said ring is combined with said rim to form a common top surface of said frame.  
     
     
         8 . The suspension type heat-dissipation fan as claimed in  claim 1 , wherein said frame is adapted to be installed on a hollow base, and wherein said hollow base has an upright enclosure defining a plurality of vent ports.  
     
     
         9 . The suspension type heat-dissipation fan as claimed in  claim 9 , wherein said enclosure has four sidewalls, and wherein said vent ports are defined in more than one of said sidewalls of said enclosure.