Patent ID: 6679686
Filing Date: 2004-01-20
Classification: F04D

Abstract:
A motor-driven air pump for inflating an inflatable body, said air pump comprising:a bottom wall with a periphery; a surrounding barrier wall which extends upwardly from said periphery to terminate at a surrounding upper edge and which has an outer surrounding wall surface that surrounds an axis, and an inner surrounding wall surface opposite to said outer surrounding wall surface in radial directions and surrounding a receiving space, said surrounding barrier wall including first inner peripheral edges and second inner peripheral edges spaced apart from each other, said first inner peripheral edges defining a first internal port and said second inner peripheral edges defining a second internal port, said first and second internal ports in fluid communication with said receiving space; a first chamber positioned radially outwardly from said first inner peripheral edges and defining a first duct which extends in an axial direction that is parallel to the axis, said first duct also positioned radially and outwardly from said surrounding barrier wall and communicating with said first internal port radially; a second chamber positioned radially outwardly from said second inner peripheral edges and defining a second duct which extends in the axial direction, said second duct also positioned radially and outwardly from said surrounding barrier wall and communicating with said second internal port radially; a first external port disposed proximate to said surrounding upper edge and communicating with said first duct such that said first external port is upstream of said first internal port when said first external port serves to introduce air in an inflating mode; a second external port adapted to be in fluid communication with the inflatable body, said second external port being disposed proximate to said bottom wall and communicating with said second duct; an impeller mounted in said receiving space and rotatable relative to said bottom wall about the axis such that, in the inflating mode, when said impeller rotates to sweep by said first internal port, air that is introduced through said first external port will be entrained via said first internal port and will be impelled to enter into said second duct via said second internal port by virtue of centrifugal force for subsequent passage through said second external port and into the inflatable body so as to inflate the inflatable body and speedily relieve said impeller from a back pressure that impedes movement of said impeller; and a drive motor disposed to drive said impeller.