Electric and stepless structure for adjusting height of desktop

Abstract

An electric structure is designed to adjust the desktop height level of a desk and is formed of a base frame on which two elevation seats are mounted. A desktop is fastened with the elevation seats such that the desktop is moved up and down along with the elevation seats. A pivoting rod is pivoted between the two elevation seats and is provided at two ends thereof with a gear which is engaged with one of two racks mounted on the base frame. The pivoting rod is driven to turn by a motor which is mounted under the desktop and is capable of turning forward or in reverse, so as to enable the desktop to rise or descend.

What is claimed is:  
     
         1 . An electric and stepless structure for adjusting height level of the desktop of a desk, said structure comprising: 
 a base frame rested stably on a surface and provided in two sides thereof with a rack extending longitudinally;    two elevation seats slidably mounted in two sides of said base frame;    a desktop fastened at two sides with said elevation seats;    a pivoting rod pivoted horizontally between said two elevation seats and located in rear side of underside of said desktop, said pivoting rod provided at two ends with a gear which is engaged with said rack of said base frame; and    an electric mechanism comprising a motor which is mounted under said desktop for driving said pivoting rod to turn.    
     
     
         2 . The structure as defined in  claim 1 , wherein said motor drives said pivoting rod via a set of a worm rod and a worm gear.  
     
     
         3 . The structure as defined in  claim 2 , wherein said motor has an output shaft perpendicular to said pivoting rod; wherein said worm rod and said worm gear are respectively mounted on said output shaft and said pivoting rod.  
     
     
         4 . The structure as defined in  claim 3 , wherein said worm rod and said worm gear are located in proximity of one end of said pivoting rod; wherein said motor is mounted in an inner side of said elevation seat corresponding in location to one side of the set of the worm rod and the worm gear, said motor being located under said desktop.  
     
     
         5 . The structure as defined in  claim 1 , wherein said base frame comprises two support feet in contact with the surface, two back columns extending uprightly from rear ends of said two support feet, and a back board fastened between said two back columns; wherein said two racks are mounted on said two back columns.  
     
     
         6 . The structure as defined in  claim 5 , wherein said back columns are rectangular tubes, with a front side tube surface having a long slot hole extending along the longitudinal direction thereof, said long slot hole being provided with a clamp board curving inward; wherein said elevation seats have a side board whose rear side is inserted into said back column via said long slot hole and is held by said two clamp boards, said side board located in an interior of said back column being provided in two sides thereof with a bearing pivoted therewith such that periphery of said bearing presses against inner wall of said back column.  
     
     
         7 . The structure as defined in  claim 6 , wherein said back column is provided in a front surface of the tube wall thereof with a plurality of cross grooves which form said rack.