External drum brake anti-falling device

An external drum brake anti-falling device, comprising:

• a carrier, having an accommodating chamber defined therein;
• a rotating drum comprising a life belt coiled thereon;
• a main shaft, crossingly arranged in said accommodating chamber for supporting said rotating drum to autorotate;
• a brake unit, arranged at an end of said rotating drum;
• and
• a drum brake module, comprising a base mounted in said accommodating chamber, a passive ring mounted on said base, and a brake lining mounted on said passive ring, wherein said base has a through hole axially and penetratingly arranged thereon and a slit radially communicating an inside and an outside of said through hole, wherein a wall surface of said through hole is regarded as a first ring surface, an outer surface of said passive ring is regarded as a second ring surface, a gap formed between said first ring surface and said second ring surface for said brake lining to be fit therein, wherein said passive ring has internally ratchet teeth arranged therein, when said life belt drives said rotating drum and said brake unit to rotate to a certain speed, said brake unit engages with said ratchet teeth under a centrifugal force, wherein when said braking unit engages with said ratchet teeth of said passive ring, said passive ring is driven to rotate, wherein when the passive ring is driven to rotate, said brake lining on said passive ring generates a friction with said first ring surface, thereby effectively decelerating rotation of said passive ring and said rotating drum so as to continuously buffer the falling speed of said life belt.