Manual negative pressure pump device

A manual negative pressure pump device comprising:

• a suction cylinder being a long pumping cylinder;
• a handle connected to a rear end of the suction cylinder;
• a pull being a rod transversally inserted into the suction cylinder;
• a rear end of the pull being connected to a pull rod which is out of the suction cylinder;
• a piston installed in the suction cylinder and being fixed at a front end of the pull rod;
• and
• an expandable spring surrounding the pull rod and a front end of the expandable spring resisting against a piston and a rear end thereof resisting a handle;
• wherein by above components, a vacuum absorbing device is formed;
• characterized in that:
• 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 screw post;
• the valve is a rubber washer and two end 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 screw thread and the thread post are retained with a predetermined distance.