Such machine can produce 600 types of cover stitches through the thread-hooking of the looper to three-needle and the side-to-side movement interweaving of satin stitches. They feature reasonable structures and simple maintenance. The high-speed and high-performance compound rotor pumps can finish the forced injection lubrication and the forced oil-return devices can solve the oil leakage problems existing for a long time in other high-speed ultra-speed interlock sewing machinery. These machinery have adopted the linkage between the needle bar thread-taking up and thread-taking-up shaft. The bottom stitches have adopted the portable throwing cam thread-taking-up, which facilitates the threading and prevents the enwinding of the bottom stitches. The two-needle three-thread, three-needle four-thread interlock stitches and the two-needle four-thread, three-needle five-thread cover stitches can be formed by the deriving and changing of the needle position assemblies.
