US Patent 10400761 Long stroke pumping unit

A long stroke pumping unit includes a tower, a counterweight assembly movable along the tower, a crown mounted atop the tower, and a drum supported by the crown and rotatable relative thereto. A belt has a first end connected to the counterweight assembly and a second end connectable to a rod string, and the belt extends over the drum. A linear electromagnetic motor is used to reciprocate the counterweight assembly along the tower. The linear electromagnetic motor includes a traveler mounted to an exterior of the counterweight assembly and a stator extending from a base of the tower to the crown and along a guide rail of the tower. The pumping unit further includes a sensor for detecting position of the counterweight assembly.