US Patent 10322918 Block

A block comprises low friction sheave with inner hole, a U-shaped frame having two holes on the curved section on the top of the frame, a continuous loop and a lock bone, wherein the sheave and U-shaped frame are connected non-rigidly by the continuous loop, which is inserted through the holes on the curved section on the top of the frame and through the inner hole of the sheave, and the continuous loop and the whole structure of the block are kept together and locked by the lock bone.