Abstract: A pumping unit has very large series connected crank and flywheel sheaves. The crank sheave is connected to oscillate a walking beam which reciprocates a horsehead attached to a bridle. The bridle is connected to a polished rod associated with a downhole pump.

Abstract: A pump stroke is matched to the operating speed of a high speed windmill. The windmill drives a hydraulic pump for a control. Changes in speed of a wind driven shaft open supply and exhaust valves to opposite ends of a hydraulic actuator to lengthen and shorten an oscillating arm thereby lengthening and shortening the stroke of an output pump. Diminishing wind to a stall speed causes the valves to operate the hydraulic cylinder to shorten the oscillating arm to zero. A pressure accumulator in the hydraulic system provides the force necessary to supply the hydraulic fluid under pressure to drive the actuator into and out of the zero position in response to the windmill shaft speed approaching and exceeding windmill stall speed.

Abstract: The following specification discloses an apparatus and method for providing lifting motion on a substantially symmetrical and compact basis for a pump through a linkage, comprising two members pivotally coupled for relative movement driven by a gear reducer. The first member is driven in a rotational manner with the second member connected thereto being rotationally driven at the same angular velocity, but in the reverse direction thereto. The angular velocity of the members can be controlled by gears, a timing chain and sprockets, or other timed drive means. As the first member rotates with the second member moving around the pivotal connection point at the same angular velocity, a lift point or pump connection is moved in a reciprocating manner to provide lift. The members can be appropriately counterbalanced. The members can also be provided on either side of the gear reducer to provide dual lift points. If a chain is used for timing the members, the chain can be enclosed in a housing with an oil bath.

Abstract: A pumping unit has a short base frame and interchangeable crank arms, while retaining a relatively low net peak torque requirement obtained through a slower upstroke and a faster downstroke.

Abstract: A pump jack for reciprocating a string of rods in a well is disclosed in which a drive shaft having an axis below the axis of a guide wheel supported above the wall has a crank arm mounted to each end of the drive shaft for rotation therewith, counterweight means having a center of gravity offset from the axis of the drive shaft are mounted to each crank arm to assist in lifting the rods, and the inner ends of pitman arms are rotatably secured to the crank arms at a pivot point offset from the axis of the drive shaft. A cross bar is secured to the outer ends of the pitman arms and a flexible linkage extends over the guide wheel, this linkage having one end carried by the cross bar and the other end adapted to be secued to the string of rods, and the crank arm is constructed so that a radial from the drive shaft passing through the pivot point of the pitman arms will be substantially tangent to the top of the guide wheel when the counterweight means is at its uppermost position.

Abstract: A tiltable horse-head shaped transmission part at the end of a rocking beam of a cornish type pump drive, is pivotably supported at one end portion of the rocking beam. The rocking beam is pivotably supported on a stationary stand. The horse-head transmission part is mounted in bearing blocks which are shiftable in longitudinal direction of the rocking beam and at the same time are tiltable about an axis which extends parallel to the longitudinal direction of the rocking beam. In this manner an accurate adjustment of the horse-head transmission part relative to a polished rod in the bore hole is made possible so that the polished rod can be accurately guided in corresponding stuffing boxes. The horse-head shaped transmission part is provided with two force application points serving for introducing tilting movement in a backward direction toward a stand and in a forward direction away from the bore hole. The force application points are equipped with fastening means for the attachment of a pulling rope.

Abstract: Variable stroke pump apparatus includes a photovoltaic array for providing electrical current to motors, one of which provides for the pumping action of a walking beam, one of which provides for movement of a control unit which varies the length of stroke of the pumping apparatus from a minimum of zero to a maximum, and one of which operates a counterweight for moving the counterweight in response to the pumping load. The apparatus includes mechanical elements which adjust the length of the stroke of the pumping arm, and a control system which controls the length of the pumping stroke in response to the output of the photovoltaic array.

Abstract: The walking beam of a pumping unit is suspended from an oscillating hanger arm. It is pivoted at one end to a crank and to a link, the other end of the latter being pivoted to a fixed position shaft. At the other end of the walking beam is a point which follows a virtually rectilinear path between a bottom dead center position and a top dead center position. This point may therefore be coupled through a rigid member to an oil well pump sucker rod line.

Abstract: A long stroke pumping unit comprising a tower mounted on a base and a counterweight-polished rod system which bestrides a top wheel mounted on the top of said tower, employs an electric motor as its prime mover. The motor rotates in a fixed direction, and through a crank mechanism the rotation of electric motor is turned into a linear reciprocating movement which is in an approximately simple harmonic fashion, and then, by means consisting of fixed pulley blocks and a travelling pulley block assembly the stroke of said reciprocating movement is multiplied and transmitted to the counterweight-polished rod system. The stroke can be easily changed by changing the effective length of the crank, also, it can be selected within a great extent by changing the number of pulleys engaged in operation.

Abstract: A pumping unit for actuating a down hole pump is disclosed for a pumping units of the type wherein a counterweight is mounted on a beam to balance a down hole load consisting substantially of pump rods. One end of the beam includes a static counterweight to balance the other end of the beam about a center pivot point, the other end of the beam including a horsehead connected to the pump rods. A prime mover is mounted on the beam for rotating beam mounted cranks including at a terminal end thereof dynamic counterweights which move in a rotational cycle in conjunction with a pumping cycle of the pumping unit. The dynamic counterweights, at a maximum lever arm from the center pivot point of the beam, counterbalance the fluid being pumped during the work stroke of the pumping unit. As the dynamic counterweight rotates it passes through a minimum lever arm from the center point corresponding to a minimum down hole load.

Abstract: An improved oil well pumping unit has an arc latch which is remotely actuable so that a workman is not required to climb onto, or be in the immediate vicinity of the arc, in order to move the arc to an inoperative position spaced from the centerline of the well.

Abstract: A pumping unit for pumping fluids from a location beneath the surface of a field. The rotary motion of a crankarm is changed to a reciprocating motion of a pair of flexible members by pitman arms pivotally secured at one end to the crankarm and at the other end to the flexible members which extend from such connection over a plurality of rollers and then vertically downward toward the well head. The flexible members are connected at their other ends to means connected to the polished rod. Portions of the flexible members and the polished rod lie in the same vertical plane so that true vertical reciprocating movement is imparted to the polished rod. The flexible members comprise non-metallic straps having a substantial width to provide stability of movement.

Abstract: A pumping unit or pump jack, of the walking beam type of class I geometry, is provided which is arranged to permit relatively efficient pumping of a well inclined to the vertical, by suitable selection of beam support configuration and location, horsehead size, configuration and position, and position of the beam support fulcrum and beam length. Also provided is an adjustable pumping unit arranged to relatively efficiently pump wells ranging from about 0.degree. to 45.degree. off-vertical, in that the pitman is adjustable in length and the angle of inclination of the longitudinal axis of the samson post is adjustable.

Abstract: A well pumping unit for use in association with an oil well, water well or the like having a downhole pump operated by a reciprocating pump rod with the pumping unit including a pair of large diameter rotatable wheels independently supported from upstanding supports on a deck, platform or skid with the wheels being interconnected by a pin to which a cable for operating the pump rod is attached. The cable is entrained over a series of pulleys and anchored to a supporting structure with one of the pulleys being a traveling pulley having a cable attached thereto extending over a head pulley and connected with the pump rod for reciprocating the pump rod when the wheels are rotated. The pin interconnecting the wheels is received in one of a plurality of radially spaced pairs of openings to enable the stroke of the pump to be varied by varying the radial position of the pin in relation to the rotational axis of the wheels.

Abstract: A portable walking beam pump jack for use in pumping liquids from an oil well having an elongated frame and an axle with wheels thereon mounted transversely on the frame for providing rolling transportation. Stabilizer pads are provided for securing the frame with respect to a ground location, after transportation. An engine is mounted on the frame and rotates a counterweighted pair of arms which are journalled for rotation adjacent to the frame and parallel to the longitudinal axis of the frame. A drive yoke is connected between the counterweighted arms and a walking beam such that rotation of the arms drives the walking beam in a rocking motion. A foldable support assembly is mounted upon the frame and supports the walking beam. The walking beam can be connected to a sucker rod for pumping from a well.

Abstract: A piston pump with a rotating piston is driven by a motor. A crank is provided on the motor shaft and has a first rolling surface on its front side. A further rolling surface engages the first rolling surface, the further rolling surface being provided on an arm which is connected fixedly to the pump piston. In one preferred embodiment, the crank is coupled with the piston in such a manner that a projection on a part connected fixedly with the piston engages a recess in the crank. An arrangement is provided for maintaining the contact between the rolling surfaces during the suction stroke of the pump. The piston controls an inlet opening and an outlet opening to the chamber in which it is movably supported. The transmission of forces during the discharge stroke through surfaces which roll on one another results in a long lifetime of the pump and quiet running.

Abstract: A pumping method, principally for oil, allows the sucker rod to fall under gravity for the first part of the downward stroke, then decelerates the sucker rod to a slow rate of descent, so creating a pause in the sucker rod's motion. Shock-absorbing means are provided to eliminate the impulsive loadings imposed upon the sucker rod at either extremity of its motion in conventional pumping methods. Hydraulically and mechanically-driven apparatus is disclosed for carrying out the method.

Abstract: The pump jack is of conventional API front-mounted geometry Class III configuration, but is provided with an angularly disposed walking beam, so as to be able to pump a slant rod string. To incorporate versatility into the unit so that a single model can be used with different wells having different angularities, there is provided: means for altering the effective length of the Pitman arms (so that the angularity of the walking beam is changed, which permits the unit to be used with a rod string having a different slant); means for bringing the counterweight into phase with the well load; and means for altering the stroke length.

Abstract: This windmill head comprises a stub tower having a rotatable platform carrying a wind driven fan which drives a transmission mechanism. The mechanism has two cranks and pitman arms at opposite sides driving two rocking beams carrying counterweights. One beam is coupled to a vertical pump rod by non-rigid members to reciprocate the pump rod. The counterweights assist the beams in pulling up the pump rod and pumped load. A tail assembly tracks the wind by rotating the platform so that the fan faces the wind. The fan furls out of the wind when wind speed is excessive. A power unit may drive the transmission mechanism when wind speed is too low and high to drive the fan. The platform is carried by bearings which prevent vertical movement of the platform and components on it while the pump rod is being pulled up and pushed down, and while the counterweights are raised and lowered. The power unit can generate electric power when the wind speed is high enough to drive the fan.

Abstract: An oil well pumping apparatus and method has an increased walking beam distance ratio of saddle pivot-polished rod distance (DE) to saddle pivot-equalizer pivot distance (DC) of at least 1.4:1. A crank arm axis (A) is positioned substantially to the rear of the equalizer pivot (C) and the pitman rod (21) is connected to the crank arm (16) at any selected stroke point along a crank arm wrist pin angle line (AB) offset at an angle (.phi.) to the center line of the crank arm. A precise counterbalancing is provided by radial adjustability of a weight assembly (17) on the crank arm, a floating safety lock assembly (64), and the addition to or subtraction from auxiliary weights (57) on a main weight member (54). The beneficial results of the present invention include reduction of peak torque requirements, elimination of gear reducer load reversals, and lower sucker rod stress throughout a very wide range of pumping applications with a universal piece of hardware.

Abstract: A pump jack having a resiliently mounted speed reducer. The pump jack comprises a frame, a sampson post, and a walking beam pivotally mounted on the sampson post. Crank shaft bearings are securely mounted on the sampson post. A speed reducer is resiliently mounted to the sampson post and coupled to the crank shaft extending through the crank shaft bearings. Thus, non-torsional forces are transferred to the sampson post, reducing wear on the speed reducer and obviating the necessity of a speed reducer of large size. This results in decreased power necessary to run the pump jack. This also allows the use of a single pitman rod configuration, which is subject to less wear than previous double pitman configurations.

Abstract: A pump jack of the type comprising a rocker arm pivotably mounted intermediate its ends on a support member, said rocker arm being divided by said pivot mounting into a sucker-rod limb and a drive limb wherein the improvement comprises a pneumatic motor pivotably attached to the drive support member and further pivotably attached to the mounting base of the pump jack to provide the power to reciprocate the pump jack. The working fluid of said pneumatic motor being natural gas which is available from the well casing of the well without any interference with the flow of the oil in the oil tube of the well thereby making use of an energy source available at any oil well without having to provide gasoline to drive a rotating type gasoline engine or electricity to drive an electric motor usually of the rotating variety.

Abstract: Method and apparatus by which a malfunctioning downhole pump of the reciprocatory type can be rendered operative by bumping the pump piston against structure associated with the pump barrel. The invention is carried out on a reciprocatory downhole pump of the type which is actuated by a rod string. The rod string is reciprocated by a pumpjack unit. A hydraulic jack apparatus is interposed between the hanger bar and polish rod clamp of the pumpjack bridle assembly so that the hydraulic jack can be extended to enable spacers to be removed or inserted at a location which changes the relative position of the polish rod clamp and hanger bar, and which also changes the relative position of the downhole pump piston and pump barrel.

Abstract: In a heavy-duty pump jack as used in oil well pumping, a leverage beam is oscillated by a motor-driven crank and the leverage beam acts upon the walking beam through an adjustable stroke controller.

Abstract: Methods and apparatus for detecting fluid pound in a sucker-rod oil well, using maximum and minimum values of sucker-rod position and of sucker-rod load to calculate a reference position and a selected load value. The apparatus automatically calculates the reference position and the selected load value according to the characteristics of the well and of the well pumping equipment. When the sucker-rod moves downward to the reference position, the actual load value is checked against the selected value and in one embodiment of the invention a warning signal develops when the amount of the load exceeds the previously selected load quantity. In another embodiment a warning signal develops when the rate of change of the load is at a maximum below the reference position. In a third embodiment a warning signal develops when a minimum rate of change of the load occurs below the reference position.

Abstract: A power transmitting device for an oil well pump of the type which utilizes a rotating power source and provides an input capable of operating a pair of cranks for driving a reciprocating pump. The power transmitting device includes a first speed reducer having an input shaft with a pinion bevel gear mounted thereon with the input shaft being operably connected to the power source. The first speed reducer also includes a ring bevel gear in meshing engagement with the pinion bevel gear which is fixedly mounted on a intermediate location of a rotatable output shaft. The output shaft operates a second speed reducer at each end thereon which is capable of providing an output which can be directly coupled to the cranks. The invention includes a method of manufacturing utilizing a number of existing components.

Abstract: A pumping unit such as used on an oil well, the unit having a base, an upright sampson post supported on the base, a drum rotatably supported to the sampson post, the drum being rotatable about its horizontal axis, a lever arm pivoted to the base and in a direction to and away from the vertical sampson post, a weight arm pivotally affixed at one end to the upper end of the lever arm, a counterweight affixed to the outer end of the weight arm, a cable extending over the drum having one end secured to the lever arm and the other end hanging in a vertical position from the drum and adapted to be attached to pumping equipment such as an oil well polish rod, a gearbox driven crank arm connected by a pitman arm to the lever arm to pivot the lever arm back and forth towards and away from the sampson post to thereby cause the cable to reciprocate over the drum and a linkage connected to the weight arm to cause it to pivot as the lever arm is pivoted so that the counterweight reacts to offset the weight of pumping equ

Abstract: A low profile pumpjack unit for producing fluid from a borehole. The pumpjack unit has a main frame supported below ground level. An upright Sampson post is supported by the main frame. A walking beam is journaled to the upper end of the Sampson post. A pitman arm is connected to and drives one end of the walking beam, while a horsehead is attached to the other end. The horsehead has a pair of curved tracks formed on the outermost surface thereof, each of which describes a segment of a circle, with the circle having a radius drawn from the Sampson post journal. The segment has a diagonal which is slightly shorter than the length of the stroke imparted into the sucker rod. The tracks abruptly curve at each end thereof to form the upper and lower ends of the horsehead. A cable bridle is received by an inside part of the horsehead, with the marginal ends of the bridle being maintained in aligned relationship respective to the two tracks which form the aforesaid circumference.

Abstract: A pump jack comprises a rocker arm one end of which is fixed to the upper end of a sucker rod. The other limb of the rocker arm has rigidly affixed thereto a downwardly-extending drive support member and a large driven pinion is eccentrically and rotatably mounted at the lower end of this drive support member. The driven pinion is engaged by a chain, which also passes around a driving pinion fixed to the base of the pump jack. This drive arrangement reduces the acceleration and shock loadings imposed upon the sucker rod at the beginning of its upstroke and reduces the size and cost of the gearbox necessary to connect a prime mover to the driving pinion.

Abstract: A pump jack system for an oil well comprising a walking beam having one end connected to a vertical pump rod while being pivoted intermediate its ends for rocking movement by means of a single vertical connecting arm driven through an eccentric connection to a cushioned wheel, preferably a pneumatic tire. The latter is driven by a motor through pulley and sprocket members which provide speed reduction to a horizontal drive shaft that engages across the surface of the wheel to drive the same. The other end of the walking beam is provided with weights slidable along the beam into adjusted positions for counterbalancing the forces imposed on the beam through the pump rod. The wheel is also suitably weighted to counterbalance the weight of the connecting arm and its bearing on the wheel. To automatically deenergize the motor when the pump rod is jammed in the well, a limit switch assembly is mounted on the beam adjacent the end at which the pump rod is located.

Abstract: A shock absorber for the pumping unit of an oil well, adapted to be placed between the walking beam and a string of sucker rods in the borehole. The shock absorber has a tubular body of steel (or an equivalent structural material) having a closed top and an open bottom. A circular top on the tubular body has a central opening through which the polished rod is adapted to pass; and a rod clamp is affixed to the polished rod--above the tubular body. A plurality of elastomeric discs, typically four or five, are positioned in a stack within the tubular body; and each disc has an external diameter which is slightly less than the internal diameter of the tubular body. The plurality of elastomeric discs rest on top of a rigid circular plate having an OD smaller than the ID of the tubular body; and the circular plate, in turn, rests on top of a rigid spool.

Abstract: This gearless straight line drive mechanism has a first shaft driven by wind power or other power source. The shaft drives rotatable crank arms which reciprocate connecting rods carrying a horizontal second shaft. The second shaft moves up and down. It carries and extends through the centers of flat, symmetrical, vertical links. Pivotally mounted guide arms are connected to ends of the links to move them in opposite arcuate directions while the second shaft is constrained by the guide arms and links to move in a precisely vertical path. The second shaft carries a pump rod for cyclically operating a lift pump. The guide arms may carry counterbalance weights or the guide arms may be loaded by springs, which apply forces via the guide arms and links to cyclically assist the second shaft and pump rod in lifting a load.

Abstract: A pump, for injecting chemicals into a well, comprising a pivot arm for synchronous movement with a well pump. The pivot arm causes reciprocation of a plunger within the body of the chemical pump. The plunger, during its upward stroke causes the entry of chemicals from an outside source into the pump body and, during its downward stroke causes the exiting of the chemicals into the well.

Abstract: A mechanism for reciprocating heavy loads such as pile drivers or pumping mechanism for deep wells in which the load to be reciprocated vertically is counter-balanced through a pair of swinging arms each of which has a pair of hair-pin type torsion springs and in which the arms are joined together through a linkage and connected to the load to be reciprocated to convert the arcuate swinging movement of the arms to vertical movement of the load.

Abstract: A deep well pump jack having a walking beam pivotally mounted on a Samson post with sucker rods depending from one end of the walking beam and a counterbalancing weight carried by the other end of the walking beam, and a prime mover is provided to rock the walking beam up and down in operation through pumping cycles. During pumping cycles, the counterbalancing weight is moved or driven in movement relative to the walking beam such that the center of gravity of the counterbalancing weight follows a vertical pattern of movement throughout each pumping cycle wherein the center of gravity travels in a substantially straight line while traveling upward and in a line of curvature directed outwardly away from the Samson pivot while traveling downward to compensate for the varying loads placed on the prime mover during each pumping cycle.

Abstract: A well sucker rod shock absorber apparatus employs cushion means located transversely of the rod string. Cushion means may also be located in association with the drive for the pumping unit that reciprocates the rod string.

Abstract: A shock absorber apparatus connected in series relationship respective to the polished rod and bridle of a pumpjack unit. The shock absorber includes a housing within which there is supported a plurality of resilient packer members stacked in sandwiched relationship. The packer members have an axial passageway formed therethrough, with the passageway of each packer member being aligned with one another, so that the polished rod is telescopingly received therethrough. The bottom of the housing is supported by the bridle, while the polished rod is supported by a plate member which bears against the uppermost packer member. This places all of the resilient packer members in compression, with the force of the compression being proportional to the weight of the sucker rod.

Abstract: Apparatus for pumping oil from a well includes a hydraulic pump for reciprocating a sucker rod string. A counterweight is connected to the sucker rod string by a chain strung over sprockets within a compact framework. The hydraulic pump applies a shock absorbing back pressure to the sucker rod.

Abstract: A well pump having a walking beam operated by a pitman and crank, the latter of which has a main counter weight connected to its end for counter balancing the weight of the rod string and one-half of the weight of the fluid pumped. An auxiliary counter weight is coupled to the crank between its driving shaft and the main counter weight and is rotated relative to the crank to aid in counter balancing the remaining portion of the fluid pumped.

Abstract: An improved pump jack assembly for reciprocating a sucker rod in a well bore is disclosed. The pump jack assembly includes a walking beam pivotally mounted for free swinging motion on a Sampson post. The walking beam includes a fixed counterweight mounted on one end and a horsehead mounted on the opposite end. The walking beam is driven in up-and-down pumping motion by a pair of balance weights which are coupled for coordinated reciprocal movement along the walking beam. The balance weights are linked together for concurrent movement and are driven by a hydraulic cylinder mounted on the counterweight end of the walking beam. The weights are so positioned that while one weight is being raised by the hydraulic cylinder, the other weight is falling due to gravity. Thus the weights help each other and greatly reduce the power requirement. The downward stroke of each end of the walking beam is limited by saddle weights which are pivotally coupled to the walking beam on opposite sides of the Sampson post.

Abstract: A polish rod jack system for an oil well pumping units that utilizes a sucker rod; incorporating a hollow hydraulic ram to raise and lower the sucker rod string; hoses and tubing to connect the hydraulic ram to a remote manifold and in turn to a hydraulic pumping source; a hydraulic and electric switchgage to stop a prime mover in the event of pumping unit and system malfunctions and or failures; quick-disconnect fittings to facilitate connection and disconnection of the hydraulic ram from the system when the well is being serviced and to allow rapid connection and disconnection of a hydraulic pump at the remote hydraulic manifold to allow the bottom hole pump to be respaced and fine tuned while the pumping unit is in operation to maximize production.

Abstract: A safety brake adapted for positively locking the crank and counter-balance weights of oil well pumping apparatus against rotation, particularly for placement and servicing of the pumping unit. In the preferred embodiment shown, a cylindrical member is bolted to a brake drum which rotates in combination with the shaft from the gear box carrying the crank and counter-balance weights. The cylindrical member has a plurality of holes disposed about its periphery. A movable engaging bar is rotatably carried on a shaft mounted to a bracket adapted for connection to the bearing cap on the gear box adjacent the brake drum. The bar contains a locking tongue for engaging the holes in the cylindrical member. The bar is rotatable from a position engaged with the cylindrical member and a position removed therefrom. A spring bias is provided to hold the bar in either of the two positions.

Abstract: The pump drive mechanism provides a high reduction drive from a continuous operating motor to a crank arm to oscillate the counterbalanced jack for a pump as used in the oil field. The drive utilizes three series of belts to obtain a reduction of 190 to 1. The belt drive reduces downtime and improves the efficiency of drives for pump jacks.

Abstract: A generally elliptical wheel is rotatably attached to the walking beam of an oilfield pumping unit in substantially the same position as a conventional horsehead. A polished rod cable sling is attached at one end to a polished rod hanger, the other end of the rod cable being trained over the front circumferential portion of the wheel and attached to an upper portion thereof. An anchor cable sling is attached at one end to a ground anchor located below the wheel, the other end of the anchor cable being trained over the back circumferential portion of the wheel and attached to the upper portion thereof.Rotation of the elliptical wheel in opposite directions on the upward and the downward movement of the walking beam causes the stroke of the polished rod to exceed the extent of movement of the walking beam by a substantial amount.

Abstract: An attachment for the horsehead of an oil well pump jack or pumping unit including a pair of strap assemblies oriented in spaced, generally parallel relation to each other with each strap assembly including two components hingedly connected to each other with each strap component including means adjustably securing it to the opposite sides of the horsehead with such means also enabling detachable connection between either of the strap components and the horsehead so that the attachment may be used for various purposes during repair, maintenance and the like and also serve as a retaining device for the wire line assembly which extends from the wire line hanger at the upper corner of the horsehead to the polished rod.

Abstract: A improved pump jack for reciprocating an oil well pump. The improved jack having a unique geometric design wherein the pump includes horizontal push rods for pushing a polish rod load around the radius of a sector head thereby greatly reducing the load on a sampson post and producing a greater mechanical advantage in the raising and lowering of the pump.

Abstract: A double-acting hydraulic cylinder unit imparts rocking movement to the walking beam of well pumping apparatus and has either (1) a stationary piston and a generally vertically reciprocating cylinder or (2) a stationary cylinder and a generally vertically reciprocating piston. Upper and lower piston rods of equal size extend from opposite sides of the piston and project through the upper and lower ends, respectively, of the cylinder. In one arrangement the lower end of the lower piston rod is pivotally anchored so as to pivotally absorb both compression and tension forces transmitted through the lower piston rod while the upper piston rod is not anchored and the primary function of the upper piston rod is to provide for equal displacement of fluid on opposite sides of the piston during vertical reciprocation of the piston.

Abstract: Two or more reciprocating pumps are controlled to deliver fluids in adjustable proportions. The pumps are connected to respective actuating levers. Each lever is reciprocated about a pivot, whose position along the lever is adjustable to vary the stroke length of the pump connected to that lever. By so controlling the stroke lengths of the different pumps, the proportions in which they deliver fluids can be adjusted.