Patent attributes
A manual negative pressure pump device comprises a suction cylinder, a handle, a pull, a piston, and an expandable spring which forms a vacuum absorbing device. A front end of the suction cylinder is a thread post with outer thread. The thread post has a central through hole and a plurality of small air holes around the through hole. The thread post is screwed with a nut of a joint. A valve and a drain-proof ring are installed between the joint and the thread post. The valve is a rubber washer and two ends of the washer have respective pins. The two pins are inserted into a central through hole of the joint and the central through hole of the thread post. The central through holes of the joint and the thread post are retained with a predetermined distance.
