Abstract:Screw drill makeup and breakout stand is a significant production facility for producing and assembling screw drill. Currently, the multi cylinder hydraulic drive locking device has a problem that the its cylinders are non-synchronous. It causes the problem of inaccurate positioning of workpiece, which eventually affects product quality. On the basis of investigation and analysis, a new structure of mechanism applying dual cylinder to drive the six teeth blocks was proposed. The six teeth blocks could be rotated at the same time, so as to solve the problem of inaccurate positioning of workpiece. Through theoretical and simulation analysis, it is confirmed that the new device of the teeth block structure can meet the strength demands in operation process.