Patent ID: 6530415
Filing Date: 2003-03-11
Classification: E06B

Abstract:
A force reducing device for adjusting shutter ropes comprising:an upper beam; a pulley box coupled to one end of said upper beam, said pulley box including a first pulley rotatably mounted therein; a rope retaining seat coupled to an opposing end of said upper beam, said rope retaining seat including a balance strip having outlets formed therein; a slat angle drive mounted to said upper beam and having a link shaft extending therefrom; a plurality of winding boxes mounted to said upper beam and respectively coupled to said link shaft, each of said winding boxes having a rolling shaft, said plurality of winding boxes being divided into two sets of winding boxes, said two sets of winding boxes being symmetrically disposed with respect to a center of said upper beam, a first of said two sets of winding boxes having a first rope fixed thereto and a second of said two sets of winding boxes having a second rope fixed thereto; a lower beam having a plurality of second pulleys mounted therein, said lower beam having a plurality of holes formed therethrough; a plurality of slats disposed between said upper beam and said lower beam and supported by a plurality of ladder ropes, each of said slats having a plurality of openings formed therethrough; a third rope having one portion thereof passing through said rope retaining seat to extending through said upper beam and pass around said first pulley of said pulley box, said third rope having another portion extending from said first pulley back through said upper beam to pass back through said rope retaining seat; and, a fixing ring securing opposing ends of said third rope to form a continuous loop with a portion thereof having a predetermined length extending from said rope retaining seat, said first and second ropes respectively extending downwardly from a respective winding box of said two sets of winding boxes, said first and second ropes respectively passing through first corresponding openings of said plurality of slats to extend around a respective pair of said plurality of second pulleys and pass upwardly through second corresponding openings of said plurality of slats to extend over a respective one of said rolling shafts, said first and second ropes having respective end portions extending from said respective rolling shafts through corresponding outlets of said balance strip, said end portions of said first and second ropes being joined together with said opposing ends of said third rope by said fixing ring, wherein displacement of a length of said joined first, second and third ropes from said rope retaining seat to raise said lower beam is matched by a corresponding length of said third rope being displaced into said upper beam to thereby maintain said predetermined length of said portion of said continuous loop substantially unchanged.