Compliant safe joint and manufacturing method thereof

A method for manufacturing a compliant safe joint, the compliant safe joint comprising an input axis circumferentially connected to a motor shaft of a DC motor;

• and the method comprising:
• circumferentially mounting a movable bridge on the input axis such that the movable bridge is slidable along an axial direction of the input axis, wherein the motor shaft is arranged in a hole in a center of the input axis;
• arranging a plurality of bearings on the movable bridge, each of the bearings having an inner ring fixed to the movable bridge and having an outer portion;
• mounting rotatably a stationary bridge on the movable bridge, the stationary bridge having a helicoid surface, the outer portion of each bearing being movable along the helicoid surface, wherein the helicoid surface is provided with a plurality of slots, and each of the bearings is constrained in respective slot when the torque applied to the stationary bridge does not exceed the predetermined threshold, the helicoid surface having a predetermined slope tangent to the outer portion of the bearing when the outer portion of the bearing moves along the helicoid surface and non-tangent to the outer portion of the bearing when the outer portion of the bearing is constrained in the slot;
• and
• connecting a flexible component to the movable bridge;
• wherein the stationary bridge is rotated about the input axis when a torque which exceeds a predetermined threshold is applied to the stationary bridge by the motor shaft, such that the bearings move with respect to the helicoid surface to cause the flexible component to be compressed and extended through the movable bridge.