Abstract: A long stroke pump rod articulation system includes a continuous belt loop attached to carry a connecting rod pin which engages a connecting rod secured to apply articulation forces to a belt supported counterbalance. The belts of the counterbalance oppose the extension of the pump rod articulating belt.

Abstract: A yo-yo variety reversing mechanism for long stroke, well pumping units, which employ a lift belt as the operative link between a winding drum and the polish rod of the well pump. Shock experienced between transfer from an upstroke to a downstroke is cushioned by the reversing mechanism or control which provides a power source off dwell period during the aforesaid stroke exchange. Further cushioning is provided by a novel winding drum for the lift belt which decreases the effective radius of the drum at the point of exchange from a downstroke to an upstroke to thus slow movement of the belt and cushion the shock of exchange from a downstroke to an upstroke.

Abstract: A self-energizing, positive engagement, fail safe mechanism for long stroke, well pumping units, whether powered mechanically or hydraulically, and which employ a lift belt. Upon failure of the sucker rod, polish rod or lift belt, a wedge shoe breaking arrangement drops and engages to jamb the lift belt against a stationary brake beam. Any continued movement of the belt only forces the safety wedge shoe brake arrangement into tighter engagement with the lift belt and brake beam. The lift belt is attached to the yoke supporting the polish rod by a bracket, dual clamping plate, bolt, and nail or pin assemblage. This same assemblage may be used to attach a counterweight to the lift belt.

Abstract: A diverse fluid pump assembly including a pair of parallel, reciprocating piston-cylinder, motor-pump combinations. The motor-pump combinations are oppositely arranged so that one is pumping while the other is charging. Motor reversal is accomplished through a unique, hydraulically actuated spool valve which is slaved to the common piston rods of the respective, tandem motor-pump combinations. The invention is intended for use primarily as a mud pump for oil well servicing or drilling rigs. Principal components are easily broken down for replacement because of wear and/or size considerations. In a preferred embodiment, the hydraulically actuated spool valve is hydraulically slaved to the motors to effect motor reversal. A unique floating stuffing box is provided on the motor side of each combination which accomodates lateral rod shifting while maintaining a fluid tight seal. The spool valve operates smoothly through five distinct stages during motor reversal thus eliminating any need for a pulsation dampener.

Abstract: An improved, multipurpose oil well rig employing hydraulically actuable components. Two, three, or four or more piston cylinder fluid motors are provided in the rig lift system, powered either by a power unit having high pressure, low volume pumping characteristics for heavy loads and low pressure, high volume pumping characteristics for light loads or by a power unit incorporating a stored energy accumulator. Novel dump/check safety and control valve means are provided in either power unit. All conventional oil well rig mechanisms are eliminated. Specifically, there are no drawworks, drums, gears, chains, sprockets, clutches, travelling blocks, mechanical brakes, transmissions or line spoolers.