Working principle The motor drives the reducer through the long-life, heavy-duty load belt, and the reducer drives the gear rotating, the gear drives the long annular rack to move up and down. When the rack moves to the point of top or bottom, the gear makes level motion to realize reversing. The rack links the belt makes up and down reciprocating motion, which makes the sucker rod up and down to draw oil. Advantages and Features 1. High efficiency. Gear-rack device makes the drive chain of entire transmission system short result in saving energy more than 25% compared with beam pumping unit. 2. Long stroke increased efficiency of pump and entire system. 3. The system runs smooth and reliable. 4. Simple structure, easy operation and low cost of maintenance 5. Superload long stroke pumping units can be customized according to customersâ?? requirements.