DC Electric Fan

Abstract

A direct-current (DC) electric fan configured for cooling purposes and for use in all places includes a base, a plurality of fixed-height interconnected inner and outer tubes extending upward from the base, and a driving motor provided in the base for driving the inner and outer tubes into reciprocal rotation, thereby simultaneously driving the fan unit mounted to each inner tube and between each two adjacent outer tubes to rotate over a predetermined rotation range. The blowing direction of each fan unit is also manually adjustable so that the blowing range of the fan can be adjusted and set according to personal needs.

1 . A direct-current (DC) electric fan, comprising: a base, a plurality of fixed-height interconnected inner and outer tubes extending upward from the base, and a driving motor provided in the base for driving the inner and outer tubes into reciprocal rotation and thereby simultaneously driving a fan unit mounted to each said inner tube and between each two adjacent said outer tubes to rotate over a predetermined rotation range, wherein each said fan unit is also manually adjustable to a desired blowing direction such that a blowing range of the electric fan can be adjusted and set as needed. 
     
     
         2 . The DC electric fan of  claim 1 , further comprising a push button unit mounted at an upper end of the interconnected inner and outer tubes and configured for turning on and off the fan units and controlling a blowing power thereof 
     
     
         3 . The DC electric fan of  claim 1 , wherein the driving motor in the base transmits power to the inner tube corresponding to each said fan unit sequentially through a connecting element, a lining block connected to the connecting element and peripherally provided with a plurality of grooves, and a lowermost said outer tube mounted around the lining block via engagement between a plurality of ridges formed on an inner periphery of the lowermost outer tube and the grooves of the lining block, each said inner tube being connected with adjacent upper and lower said outer tubes via engagement between engaging portions which extend respectively from an upper end and a lower end of each said inner tube and recesses which are provided on the adjacent upper and lower outer tubes and correspond in position to the engaging portions, thus allowing the interconnected inner and outer tubes to rotate simultaneously and thereby drive the fan units to rotate reciprocally over the predetermined rotation range. 
     
     
         4 . The DC electric fan of  claim 3 , further comprising a push button unit mounted at an upper end of the interconnected inner and outer tubes and configured for turning on and off the fan units and controlling a blowing power thereof 
     
     
         5 . The DC electric fan of  claim 3 , wherein each said inner tube is concavely provided with a slot extending over a predetermined range and a cavity formed within the slot and having slightly protruding left and right edges, and each said fan unit has a protuberance corresponding in position to and engageable in the cavity of a corresponding said inner tube, each said fan unit being manually rotatable according to the desired blowing direction so that the protuberance of the fan unit is driven out of the cavity of the corresponding inner tube and moved to a central position of a desired blowing range, thus allowing the fan unit to be driven by the driving motor to rotate over the desired blowing range. 
     
     
         6 . The DC electric fan of  claim 3 , wherein resilient rings are mounted around each said inner tube at positions where each said inner tube is connected with the adjacent upper and lower outer tubes respectively, thus enhancing engagement between connecting portions of each said inner tube and the adjacent upper and lower outer tubes. 
     
     
         7 . The DC electric fan of  claim 3 , wherein the driving motor for driving the fan units is an eccentric motor, and an axle of the eccentric motor is connected with a swing arm for transmitting power to the lining block and the lowermost outer tube, delivering a predetermined rotation of the driving motor to each said fan unit, and thus simultaneously driving each said fan unit into reciprocal rotation.