With the continuous research and innovation of our company’s technical team, recently, our company has received three new utility model patents, which are: 1) The Lifting And Hinge Rock Arm For Open And Close Port Cover, 2) Piston Effect Self-sealing Port Cover Seal Structure as well as 3) Interlocking And Venting Device With Self-Limitation Position, Anti-stuck And Locking Function. This is another achievement of Dipper’s continuous research and development innovation.