Safe disengaging device for the pull cord of a blind

A safe disengaging device for a pull cord of a blind comprising:

• a male support base fixed at a preset location on the upper frame of a blind, said male support base provided with a clasping block protruding forward at a preset location, said clasping block having its upper side formed with an engage shoulder;
• a female support base having its lower end tied with a pull cord of said blind, said female support base having its upper side extending upward to form an elastic member with an upper free end, said free end of said elastic member bent inward horizontally to form an engage hook to be held on said engage shoulder of said male support base, said female support base further provided with an annular holding arm, said annular holding arm being C-shaped and positioned at the outer side of said elastic member, said C-shaped holding arm having its opposite ends respectively fixed with a clasping member extending vertically and protruding inward, with a deforming space formed between said holding arm and the outer side of said elastic member for said elastic member to be deformed therein;
• and
• said female support base fitted on said male support base from under said male support base, said engage hook of said elastic member elastically held on said engage shoulder of said male support base, said holding arm of said female support base firmly holding opposite walls of said clasping block of said male support base, enabling said female support base to be firmly fitted on said male support base, said elastic member deformed outward to force said engage hook to be disengaged from said engage shoulder of said male support base when said pull cord at the lower end of said female support base is drawn by a preset force, letting said female support base disengage from said male support base.