Patent ID: 6116323
Filing Date: 2000-09-12
Classification: E06B

Abstract:
A dual function dragging device for a curtain comprising a plurality of slats arranged below a frame, said slats strung by a ladder rope and parallel to each other, said slats being able to move upward and downward by a dragging cord, said ladder rope and cord extending into said frame, said dragging device further comprising a shaft for wrapping of said cord and driven by a driving shaft of a driving means and a clutch for driving said ladder rope being coaxial with said shaft, said clutch performing an initial dragging to said slats thus providing dual function for opening/closing said curtain and changing angle of said slats, said clutch having at least one ring groove for coupling with said ladder rope, a plurality in holes of said ring groove, at least one bump on said ladder rope, said ladder rope and said ring groove having friction there between and said bumps being embedded into said holes or being released therefrom upon reaching another side of said ring groove as said clutch is rotated thus changing the angle of said slats, said bumps being larger than the diameter of said ladder rope, said clutch having a magnetic member and said balls being magnetically attracted to said magnetic member such that said balls can be urged forward and in holes received by respective ones of said, said shaft having a winding wheel with bead grooves on one axial end thereof and coaxially driven said driving means, said driving means comprising by a motor, said frame having a through hole for said cord and being aligned with said bead grooves, said cord being a beaded cord with one end arranged on another end of said winding shaft, a bottom of each bead groove being a ramp surface, two side surfaces of each bead groove being inclined surfaces, bottom exit of each bead groove being adjacent to an outer surface of said winding shaft, a length of line between two adjacent beads being smaller than a diameter of said bead, said winding wheel being of cone shape.