device 10 is attached by shackle 36 to an element of the structure on which a worker or other person is performing a task at a great height above the ground snap hook 14 or a similar device is attached to the end of cable lifeline 12 and is then attached to a belt or harness worn by the worker or other person who is performing the task safety device 10 permits a free range of motion on the part of the worker as long as the worker does not away from safety device 10 a distance greater than the length of cable 12 provided by safety device 10 due to the continuous turning force exerted by spiral motor spring 76 cable 12 is automatically rewound onto take up portion 46 of cable drum 44 as the worker walks closer to safety device 10 in the event that the worker should fall the high rate of speed at which cable drum 44 turns to pay out cable 12 in response thereto causes pawls 86 to overcome the contracting force of springs 88 and pawls 86 engage ratchet teeth 100 of ratchet surface 102 on brake driving hub 104 brake driving hub 104 which is rotatably mounted to main shaft 24 but normally does not rotate about main shaft 24 begins to rotate with cable drum 44 once pawls 86 have engaged ratchet teeth 100 of ratchet surface 102 they cannot become disengaged until cable drum 44 begins to rotate backward to rewind cable 12 onto take up portion 46 upon the rotation of brake driving hub 104.