Articulated plunger rod pump

A reciprocating rod pump apparatus comprising:

• a pump barrel having an inner bore;
• a plunger comprising at least two plunger segments, disposed within the pump barrel;
• a rod string;
• a valve rod that extends from outside of the pump barrel to an interior of the pump barrel and connects the rod string to the plunger, the valve rod having a longitudinal axis;
• a first articulating connector disposed between and connecting a first plunger segment and a second plunger segment of the at least two plunger segments, wherein the first articulating connector is adapted to allow for deflection between the first and second plunger segments;
• and
• a second articulating connector disposed between and connecting the valve rod and the rod string, wherein the second articulating connector is adapted to allow for deflection between the valve rod and the rod string,
• wherein the second articulating connector comprises a swivel sub attached to the valve rod and a retaining collar attached to the rod string, wherein the swivel sub has a rotation axis extending along the longitudinal axis, and the swivel sub is retained by the retaining collar and freely rotatable around the rotation axis and pivotable within the retaining collar.