Portable walking beam pump jack

Claim 1

A portable walking beam pump jack for use in pumping liquids from an oil well, comprising: an elongated frame having a longitudinal axis and front and rear ends, said frame also including first and second support seats disposed at vertically spaced apart locations between said front end and said rear end of said frame; a towing receptacle extending from the front end of said frame for connecting said frame to a towing vehicle; an axle connected transversely across said frame; ground engaging wheels connected to said axle for supporting said frame for rolling transportation; stabilizing means for securing said frame with respect to a ground location; a walking beam having a first end, a midportion and a second end, said second end being adapted for connection to a pumping rod; an engine mounted on said frame; a pair of arms counterweighted for balancing a pumping rod connected to said walking beam, journalled for rotation in parallel planes adjacent to said frame and parallel to said longitudinal axis of said frame, and connected to said engine for rotation responsive to said engine; a drive yoke extending from said drive arms to said first end of said walking beam, rotation of said arms thereby driving said walking beam in a rocking motion; a support assembly foldably mounted on said frame and upon which said midportion of said walking beam is pivotally connected, said support assembly said arms and said drive yoke being foldable together, from a first, fixed position in which said walking beam arms and yoke are supported in a raised position for rocking in a pumping motion to a second, fixed position disposed downwardly and forwardly from said first fixed position and in which said walking beam arms and yoke are held in a lowered position for transportation; said support assembly including: a rear support having first and second ends, said first end being connected to the midportion of said walking beam and said second end being pivotally connected to said rear end of said frame for pivotal, arcuate movement of said rear support in a plane parallel to said longitudinal axis of said frame; and a front support having first and second ends, said first end of said front support being connected to the midportion of said walking beam, and said second end of said front support being movable between said first support seat for holding said support assembly in said first, fixed position and said second seat for holding said support assembly in said second, fixed position; and hydraulic cylinder means connected between said frame and said support assembly for moving said support assembly between said first, fixed position and said second fixed position.