An inverse cam mechanism has been used to successfully solve the problem of discharging the scraps from the multi-position stamping die for the needles for sewing machines.

Some methods and measures are studied,such as the rational readjustment of all kinds of error,the surveying plan,the precise azimuth transfer of shaft,and the auto guiding system with traverse control improving the orientation precision of gyro theodolite,in order to take into consideration the feature of dynamic driving in of the underground pipe driving project.