US Patent 9701407 Emergency stop for blades of drone

Disclosed is a drone having at least one rotor. The at least one rotor comprises a mast and at least two blades having a proximal end and a distal end. The at least two blades are arranged in connection with the mast by their proximal ends. The at least one of the blades comprises an electrically conductive element extending a distance D between its distal end and its proximal end. The electrically conductive element is electrically coupled with means for stopping the blades, thus forming an electrical circuit. The means for stopping the blades is arranged to be actioned when at least one electrical property of the electrical circuit change.