Rolled-up blind driving mechanism

Abstract

A rolled-up blind driving mechanism includes a chain of beads adapted to rotate a chain wheel assembly to further drive a torsional spring on a spring holder to rotate an axle sleeve in rolling up/letting off the blind, the torsional spring having two end tips, a curved connecting arm, and two coils connected between the connecting arm and the end tips of the rolled-up blind, the connecting arm and the end tips being disposed at two sides of an inside protruding portion of the axle sleeve for enabling the axle sleeve to be rotated to roll up/let off the blind of the rolled-up blind when pulling the chain of beads to rotate the chain wheel assembly clockwise/counter-clockwise on the spring holder.

What the invention claimed is:  
     
         1 . A rolled-up blind driving mechanism comprising: 
 a chain wheel assembly, said chain wheel assembly comprising a chain wheel, a center through hole extended through the center of said chain wheel, a semispherical shell axially extended from one side of said chain wheel around the center through hole of said chain wheel, said semispherical shell having a first side edge and a second side edge;    a chain of beads hung on said chain wheel of said chain wheel assembly for pulling by hand to rotate said chain wheel assembly;    a wheel cap, said wheel cap comprising a cap ring adapted to receive the semispherical shell of said chain wheel assembly, and a smoothly arched cap flange perpendicularly backwardly extended from the periphery of said cap ring and adapted to hold said chain of beads in engagement with said chain wheel of said chain wheel assembly;    an axle sleeve, said axle sleeve comprising a sleeve hole axially extended through front and rear ends thereof and adapted to receive the semispherical shell of said chain wheel assembly, a retaining groove axially extended in the periphery thereof for engagement with the positioning rid of the blind roller of the rolled-up blind in which the rolled-up blind driving mechanism is installed, and an inside protruding portion protruded from an inside wall thereof, said inside protruding portion having a first sidewall and a second sidewall;    a spring holder, said spring holder comprising an end cap engaged with one side of said chain wheel of said chain wheel assembly, and a shaft axially extended from the center of one side of said end cap and inserted into the center through hole of said chain wheel assembly;    a torsional spring mounted on the shaft of said spring holder; and    fastener means, which secures said spring holder to said axle sleeve;    characterized in that said torsional spring comprises a curved connecting arm inserted into the space inside said axle sleeve between the second side edge of said semispherical shell of said chain wheel assembly and the second sidewall of said inside protruding portion of said axle sleeve, two coils mounted on the shaft of said spring holder inside said axle sleeve, said coils each having an inner end respectively connected to two distal ends of said curved connecting arm and an outer end, and two end tips respectively connected to the outer end of each of said coils and inserted into the space inside said axle sleeve between the first side edge of said semispherical shell of said chain wheel assembly and the first sidewall of said inside protruding portion of said axle sleeve.    
     
     
         2 . The rolled-up blind driving mechanism as claimed in  claim 1  wherein said torsional spring is made of a spring wire by winding.  
     
     
         3 . The rolled-up blind driving mechanism as claimed in  claim 1  wherein said spring holder comprises a pinhole of non-circular cross section axially extended through said end cap and said shaft; said fastener means is a split pin inserted through said pinhole of said spring holder to secure said spring holder to said axle sleeve, said split pin comprising a conical first end disposed outside said spring holder and said axle sleeve, a shoulder stopped at one end of said axle sleeve, a second end of non-circular cross section fitted into said pinhole of said spring holder, and a stop rod extended from said second end for positioning in the bracket of the rolled-up blind in which the rolled-up blind driving mechanism is installed.