Steel Base: ensures the proper alignment of the components and is usually set on a concrete foundation.
Samson post: may have three or four legs and is the strongest member of the unit, since it carries the greatest loads.
Saddle Bearing: the pivot point for the walking beam.
Walking beam: a heavy steel beam placed over the saddle bearing, with a sufficiently great metal cross-section to withstand the bending loads caused by the well load and the driving force of the pitmans.
Horsehead: the well side of the walking beam and has a curvature profile to ensure PL is moved vertically.
Wireline Hanger (bridle): moves the polished rod.
Equalizer: a short section of a lighter beam set across the walking beam, transmitting polished rod loads from the walking beam evenly to the two pitmans.
Pitman: are steel rods that connect at their lower ends to the crank arms with the wrist pins. These pins are mounted on the wrist pin bearings, which allow the required rotary movement between the parts.
Cranks: are situated on both sides of the gear reducer and are driven by the slow-speed shaft (crankshaft) of the gear reducer.
Counterweights: are attached to the crank arms, allowing for adjustment along the crank arm axis to balance pumping unit loads in upstroke and downstroke.
Prime Mover: Provide the required power fo the pumping unit.
Gear Reducer: reduces the high speed of the prime mover to the speed required for pumping and duplicates the prime mover torque.
Brake assembly: that can stop the unit at any point.
V-belt: Transmit the power from the prime mover to the gear reducer.