Beam Pumping Unit Principles and Components 

A beam pumping unit is a machine for translating rotary motion from a crankshaft to a linear reciprocating motion for the purpose of transferring mechanical power to a down-hole pump. The purpose, simply stated, of the basic system is to transmit energy from the surface to the downhole pump. A nodding donkey, horsehead pump or sucker rod pump are all commonly-used names for the beam pump. Also called a walking beam pump, the machine takes its name from the unique pumping motion the exposed elements of the pump produce. The pump uses a drive motor called a prime mover to power the pump. Most important parts of the conventional units are: Base, Counterweight, Crank, Samson Post, Horse Head, Walking Beam, Equalizer, Pitman, Gear Reducer, Brake and Prime Mover.