Bolt locking device

The invention relates to the technical field of screwed fittings and in particular relates to a bolt locking device. The bolt locking device comprises a locking device main body and a locking piece, wherein the locking piece is mainly composed of a central bolt and a nut locking disc; the central bolt is arranged in the middle of the locking device main body; the nut locking disc is fixedly arranged at the end of the locking device main body by virtue of a locking bolt; the nut locking disc is fixedly connected with the central bolt by virtue of a flange nut inserted into the shaft hole of thenut locking disc; a flower-like clamping groove attached to the outer wall of the flange nut is formed in the inner wall of the shaft hole of the nut locking disc. The flower-like clamping groove inthe middle of the nut locking disc is attached to the outer wall of the flange nut for preventing looseness, and locking is realized by enabling the locking nut to pass through kidney-shaped through holes. Meanwhile, due to th