US Patent 10890175 Direct drive pumping unit

This disclosure relates to a direct drive pumping unit having a reciprocator for reciprocating a sucker rod string and a sensor for detecting position of a polished rod. The reciprocator includes a tower for surrounding a wellhead. The polished rod is connectable to the sucker rod string and has an inner thread open to a top thereof and extends along at least most of a length thereof. A screw shaft extends into the polished rod and interacts with the inner thread. A motor is mounted to the tower, torsionally connected to the screw shaft, and operable to rotate the screw shaft relative to the polished rod.