A pumping unit with variable work stroke and return stroke torque factor characteristics

Abstract From the Canadian patent

A pumping unit system having vertical sampson post a walking beam pivotally supported at the upper end of the sampson post and a horsehead affixed at a forward end thereof that supports a reciprocated sucker rod string including a gear reducer mounted at selectable positions on the walking beam and having a horizontally extending drive shaft a crank arm affixed to the drive shaft the spacing between a selectable length pitman rod having a first end secured to said crank arm and a second end having a pitman bearing that is selectably mountable to a plurality of pitman bearing locations and a prime mover connected to the gear reducer and wherein the characteristics of the pumping unit are …