Centrifugal brake mechanism

A controlled descent device, comprising:

• a wearable harness;
• a support structure attached to the harness and having a cable release opening for passage of portions of a spooled cable therethrough;
• and
• a drum device comprising the spooled cable and a brake mechanism configured to regulate a speed of release of the cable from the drum device, said brake mechanism comprises:
• a circular wheel configured to rotate about an axis of rotation thereof and comprising a circular central cavity and an inner wall encircling the cavity;
• an axle extending along and rotatable about said axis of rotation inside said central cavity;
• two or more parallel shaft rods attached to the axle and extending substantially perpendicular to the axis of rotation inside the cavity;
• a gear system configured to transfer rotations of said wheel into counter-rotations of said axle;
• one or more brake elements mounted on said two or more parallel shaft rods, each of the one or more brake elements having two or more pass-through bores for slidably moving along said two or more parallel shaft rods inside said central cavity, and two or more springs mounted over at least one of said two or more parallel shaft rods between the brake element and the axle, said one or more brake elements being configured and operable to radially slide over the parallel shaft rods towards the inner wall of the wheel encircling said cavity in response to the counter-rotations of said axle;
• a friction enhancement mechanism for increasing friction forces responsive to increase in angular velocity of the wheel, said friction enhancement mechanism being configured for providing additional engagement between the circular wheel and the brake element and comprising one or more circular rails and corresponding one or more curved grooves engageable with said one or more rails, to thereby progressively increase friction between said one or more brake elements and the inner wall of the wheel responsive to increase in the angular velocity of the wheel.

A drum device, comprising:

• a support structure;
• a circular wheel located inside said support structure and configured and operable to rotate about an axis of rotation thereof;
• an axle mounted inside a cavity of the wheel, the axle extending along and rotatable about said axis of rotation;
• two or more parallel shaft rods attached to the axle and extending substantially perpendicular to the axis of rotation;
• spring element mounted over at least one of said shaft rods;
• a gear system configured and operable to transfer rotations of said wheel into counter-rotations of said axle;
• one or more brake elements mounted on said two or more parallel shaft rods, each brake element having two or more pass-through bores for sliding over said two or more parallel shaft rods towards an inner wall encircling the cavity of the wheel in response to the counter-rotations of said axle;
• and
• a friction enhancement mechanism for increasing friction forces responsive to increase in angular velocity of the wheel, said friction enhancement mechanism being configured for providing additional engagement between the circular wheel and the brake element, said friction enhancement mechanism comprising one or more circular rails and corresponding one or more curved grooves engageable with said one or more rails, to thereby progressively increase friction between said one or more brake elements and the inner wall of the wheel responsive to increase in the angular velocity of the wheel.