Patent ID: 8240221

Claim:
In a surface pumping unit ( 10 ) for reciprocating a downhole pump located in a well having a substantially vertical wellhead ( 9 ), the pumping unit ( 10 ) including a walking beam ( 24 ) pivotally mounted and supported by a saddle bearing ( 15 ) atop a frame ( 13 , 11 , 17 ), said walking beam ( 24 ) pivotally coupled to a pitman arm ( 26 ) by an equalizer bearing ( 25 ), said pitman arm ( 26 ) pivotally coupled to a crank arm ( 20 ) by a crank pin bearing ( 19 ), said crank arm connected to a crankshaft ( 22 ) for rotation about a centerline of said crankshaft ( 22 ), said crankshaft ( 22 ) being rotatively mounted to said frame, whereby said crank arm ( 20 ), said pitman arm ( 26 ), said walking beam and said frame collectively define a four-bar linkage mechanism operable to cause said walking beam ( 24 ) to seesaw about said saddle bearing ( 15 ) upon rotation of crank arm ( 20 ), said four-bar linkage mechanism characterized by a predetermined linkage geometry defined by distances between a centerline of said saddle bearing ( 15 ), a centerline of said equalizer bearing ( 25 ), a centerline of said crank pin bearing ( 19 ) and the centerline of said crankshaft ( 22 ), a front end of said walking beam terminating with an arcuate horse head ( 28 ) that is coupled to said downhole pump by a rod string ( 36 ) that passes through said wellhead ( 9 ), the improvement comprising: a bend ( 90 ) formed in said walking beam ( 24 ″, 224 ) forward of said fulcrum point; whereby said pumping unit ( 100 , 200 ) is arranged to permit pumping at a wellhead ( 9 ′) characterized by a wellhead axis ( 48 ) that is inclined from the vertical while maintaining said predetermined linkage geometry.