Double pulley comprising: - a support flange; - first and second rotation shafts mounted fixedly to the support flange and extending in a first direction from at least a face of the support flange; - first and second sheaves mounted rotatable respectively around the first and second rotation shafts, the first and second sheaves defining a running line along a cable, the running line being perpendicular to the first direction; - a support hole defined in the support flange and designed to receive a connector connected to a person to be rescued; characterized in that the double pulley comprises: - first and second flanges mounted rotatable with respect to the support flange respectively around the first and second rotation shafts, the first and second flanges being separated from the support flange respectively by the first and second sheaves, each of the first and second flanges being mounted rotatable between a first position and a second position independently from the other flange, the first flange defining a first retaining ring at least with the first sheave and the support flange and the second flange defining a second retaining ring at least with the second sheave and the support flange, the first position of the first flange or the second flange allowing the cable to be inserted respectively in the first retaining ring or the second retaining ring on the first sheave or the second sheave, the second position preventing the cable from being extracted; - a first blocking system configured to present a first position blocking the first flange in the first position to keep the first retaining ring closed and to present a second position allowing movement of the first flange between the first position and the second position; - a second blocking system configured to present a first position blocking the second flange in the first position to keep the second retaining ring closed and to present a second position allowing movement of the second flange between the first position and the second position, the first blocking system and second blocking system each having an operation independent from the other blocking system. - a support flange; - first and second rotation shafts mounted fixedly to the support flange and extending in a first direction from at least a face of the support flange; - first and second sheaves mounted rotatable respectively around the first and second rotation shafts, the first and second sheaves defining a running line along a cable, the running line being perpendicular to the first direction; - a support hole defined in the support flange and designed to receive a connector connected to a person to be rescued; - first and second flanges mounted rotatable with respect to the support flange respectively around the first and second rotation shafts, the first and second flanges being separated from the support flange respectively by the first and second sheaves, each of the first and second flanges being mounted rotatable between a first position and a second position independently from the other flange, the first flange defining a first retaining ring at least with the first sheave and the support flange and the second flange defining a second retaining ring at least with the second sheave and the support flange, the first position of the first flange or the second flange allowing the cable to be inserted respectively in the first retaining ring or the second retaining ring on the first sheave or the second sheave, the second position preventing the cable from being extracted; - a first blocking system configured to present a first position blocking the first flange in the first position to keep the first retaining ring closed and to present a second position allowing movement of the first flange between the first position and the second position; - a second blocking system configured to present a first position blocking the second flange in the first position to keep the second retaining ring closed and to present a second position allowing movement of the second flange between the first position and the second position, the first blocking system and second blocking system each having an operation independent from the other blocking system.