US Patent 9617128 Pulley device

The pulley device comprises first and second pulleys each provided with a set of sheaves. The two pulleys are designed to be respectively fixed to a fixed point and to a person to be rescued. A rope is fixed to one of the two pulleys and arranged in such a way that the first pulley moves towards the second pulley when a pull is exerted on the rope. An enclosure connects the first pulley to the second pulley and surrounds the path of the rope between the two pulleys. One end of the rope extends outwards from the enclosure to enable a pull to be exerted on the end of the rope.