The hand knob and the shell employ a screwedjoint, which can reach the self-hold request of the device.
手柄与外壳采用螺纹连接，可以满足机构的自锁要求。
2
In chapter two, the prosperity of the motion, force and screwedjoint of the surface dynamic rotating drilling downhole drilling string has been discussed.
第二章分析探讨了地面动力旋转钻井井下钻柱的运动状态、受力及螺纹联接的特性。
3
A protecting joint is added at power head rod joint in order to prevent power head rod joint abrasion when rod is screwed or unscrewed.