The invention belongs to 
pipe-fitting-like 
assembly equipment for heavy-weight and large length 
diameter ratio, and particularly relates to a 
pipe-fitting-like threaded screwing mechanism for a heavy-weight and large length-
diameter ratio. The 
pipe-fitting-like threaded screwing mechanism comprises a 
machine body, a screwing force applying mechanism installed on the 
machine body, an automatic positioning and anti-twisting mechanism in stalled on the 
machine body and automatic attitude adjusting mechanisms installed on the machine body. The positioning and attitude adjustment of the screwed 
assembly pieces are partially completed through the 
joint action of an air cylinder and an electric cylinder, all the attitude adjustment actions are fully completed through a 
servo electric cylinder acting on the automatic attitude adjustment mechanisms, the 
butt joint of the pieces to be screwed after positioning and attitude adjustment is completed through the action of the 
servo electric cylinder, the actual work of screwing is completed through the torque output of a 
servo motor acting on the screwing force applying mechanism, and the monitoring and adjustment of the action, torque and otherrelated data are completed by all actions through a servo 
system cooperating with a displacement sensor. According to the pipe-fitting-like threaded screwing mechanism, the whole project is automatically completed without manual assistance, and the high-precision actions of positioning, adjusting, moving and the like are efficient, accurate and safe.