Pulley descender

Self-clamping descender with pulley for a rope comprising:

• a first flange provided with a rope clamping area,
• a rope channel designed to receive a rope,
• a pulley designed to come into contact with the rope and fitted in rotary manner around a first rotation shaft, the first rotation shaft being fixed to a support and defining a first axis of rotation, the pulley being configured to only rotate in a first direction of rotation around the first axis of rotation and to prevent rotation in the second direction of rotation around said first axis of rotation,
• the support fitted movable in rotation between a first position and a second position around a second rotation shaft fixed to the first flange, the second rotation shaft defining a second axis of rotation,
• a blocking cam fixed on the support, the blocking cam being movable in rotation with respect to the first flange around the second rotation shaft so as to move towards or away from the rope clamping area,
• wherein
• the first axis of rotation is offset from the second axis of rotation by a smaller distance than a radius of the pulley,
• the first rotation shaft is movable around the second axis of rotation and movable with respect to the rope clamping area,
• the first and second axis of rotation are arranged so that application of a force on the rope makes the pulley to rotate in the first direction of rotation generating a force urging the blocking cam away from the rope clamping area, and application of a force on the rope makes the pulley to rotate in the second direction of rotation generating a force urging the blocking cam towards the rope clamping area.