Switch and Motor-Cooling Device for an Electric Fan

Abstract

A switch and a motor-cooling device for an electric fan comprise a motor, a housing, a controller and a knob. The housing is defined with a concave portion in an end thereof, and on the bottom of the concave portion are provided plural assembling portions. The concave portion is formed with an outward-enlarged arc-shaped guiding surface around a periphery thereof and interiorly defined with plural inlet holes. The controller and the knob are assembled to the assembling portions. The knob is exteriorly provided with a tapered arc-shaped guiding surface. With the guiding surface of the housing and the guiding surface of the knob, the air within the angular scope of the concave portion and behind the knob can be completely sucked into the concave portion, thus increasing the amount of the air sucked into the housing and obtaining the optimal heat dissipation efficiency.

What is claimed is: 
     
         1 . A switch and a motor-cooling device for an electric fan comprising:
 a motor being connected to plural fan blades;   a housing having one end connected to the motor and an end cap and enclosing the motor, the other end of the housing being defined with a concave portion, on a bottom of the concave portion being provided plural assembling portions, the concave portion being formed with an outward-enlarged arc-shaped guiding surface around a periphery thereof, and the concave portion being further interiorly defined with plural inlet holes;   a controller controlling a speed and ON/OFF of the motor and being assembled to the assembling portions in the concave portion of the housing, the controller being further provided with an assembling rod; and   a knob and the controller constitute the switch, the knob being interiorly defined with an assembling hole in a surface thereof which is located opposite the controller and exteriorly formed with a tapered arc-shaped guiding surface.   
     
     
         2 . The switch and the motor-cooling device for an electric fan as claimed in  claim 1 , wherein the housing is defined with plural air outlet holes in the other end thereof. 
     
     
         3 . The switch and the motor-cooling device for an electric fan as claimed in  claim 1 , wherein the controller is provided at both sides thereof with assembling portions to be assembled to the assembling portions in the concave portion of the housing by screw. 
     
     
         4 . The switch and the motor-cooling device for an electric fan as claimed in  claim 1 , wherein the guiding surface of the knob is provided with plural anti-slip portions around a periphery thereof.