US2152701A - Counterbalance for oil pumping apparatus - Google Patents

Description

COUNTERBALANGE FOR OIL PUMPING APPARATUS Original Filed Nov. 16, 1936 INVENTOR- hheef /Z/'Z4 F/ 40 M r ATTORNEY Patented Apr. 4, .1939

UNITED STATES COUNTERBALANCE FOR OIL PUlVIPING APPARATUS Warren M. Mansfield, Glendale, Calif., assignor to Emsco Derrick & Equipment Company, Los Angeles, Calif., a corporation of California Application November 16, 1936, Serial No. 111,010

Renewed November 21, 1938 8 Claims.

My invention relates to pumping apparatus commonly employed for pumping oil from oil wells, and it particularly relates to a counterbalance pumping apparatus and also a unique counterbalance having numerous features and. adva tages over the prior art.

In order that the objects, features, and advantages of my invention may be better understood I will briefly refer to the oil pumping art in which my invention finds extensive use. The pump proper is placed in the Well below the oil level and the pump plmiger thereof is connected by means of a string of sucker rods to an operating means at the surface of the ground: The operating means includes an operating crank driven by suitable drive means; and interconnecting means connected between the operating crank and the string of sucker rods. A very common type of interconnecting means has a walking beam connected to the sucker rods and a pitman connected to the walking beam and the operating crank. To obtain optimum operating conditions counterbalances are employed to counterbalance the weight of the string of sucker rods and pump plunger, and approximately one-half the weight of the column of oil supported by the plunger.

It is an object of my invention to provide pumping apparatus in which there is a counterbalance mounted on the operating crank and which is adjustable into various positions to obtain the de- 30 sired counterbalancing effect.

It is an object of my invention to provide a counterbalance which when selected for a particular well is of approximately the desired weight and in which the counterbalance may thereafter be adjusted as required in order to obtain optimum operating conditions.

It is the usual practice to place the counterbalance so that its center of mass is on the radial axis of the operating crank. It is found, however, that if the center of mass of the counterbalance is moved forwardly or rearwardly with respect to the radial axis of the crank, that operating conditions may sometimes be improved. It is one of the objects of my invention to provide a counter- 45 balance in which the center of mass thereof may be on the radial axis of the crank or may be moved forwardly or rearwardly of this axis by a simple adjustment of the counterbalance.

The rig of the well is used for operations other 50 than pumping, and when so used a counterbalance is an interference to the operation of the apparatus and. must, therefore, be eliminated either by detaching it from the apparatus or moving it into a concentric or neutral position. It is an object of my invention to provide a counterbalance which may be employed as a counterbalance during pumping operations and which is adjustable so that it may be positioned with its center of mass substantially concentric to the center of ro- 5 tation of the operating crank on which it is mounted, and in which position acts as a flywheel. 7

A further object of my invention is to provide a counterbalance which includes two counter- 10 weights positioned on opposite sides of the operating crank and pivotally connected thereto, and in which the counterweights are independently adjustable into any position between extended, or retracted or neutral position.

It is a further object of my invention to provide a counterbalance of the character pointed out in the preceding paragraph which includes separate adjusting means for each of the counterweights which is in the form of rods, one of which is pivoted to one of the counterweights, the other of which is pivoted to the otherof the counterweights, and in which both of the rods are adjustably connected to the operating crank.

A still further object of my invention is to provide a counterbalance in which a counterweight thereof is provided with a sideWardly-facing pocket in which extra weights may be secured in order to increase the counterbalancing effect as desired.

I believe my invention which incorporates the objects and advantages pointed out heretofore to be broadly new and that various modifications and alterations may be made in the construction without departing from the spirit and scope of my invention. For the purpose of teaching those skilled in the art as to how my invention may be practiced I have selected for illustration a preferred form of my invention. It should be understood, however, that I do not wish to be limited to'the precise details which are disclosed herein. In the accompanying drawing and following description various additional objects, features, and advantages of my invention will be pointed out.

Referring to the drawing:

Fig. 1 is a diagrammatic View illustrating the utility of my invention.

Fig. 2 is an enlarged elevational view showing the operating crank and counterbalance of my invention, the counterbalance being in extended counterbalancing position.

Fig. 3 is an elevational view taken as indicated by the arrow 3 of Fig. 2. 55

Fig. 4 is a fragmentary sectional view taken on the line 4-4 of Fig. 2.

Fig. 5 is a fragmentary sectional view taken on the line 5-5 of Fig. 4.

Fig. 6 is a fragmentary sectional view taken on the line 66 of Fig. 3.

Fig. '7 is a view resembling Fig. 2 but showing the counterbalance in neutral or concentric position.

Referring to the drawing in detail, and particularly Fig. 1, the numeral represents the usual type of walking beam which is pivotally supported on the upper end of a Samson post I2. The right end of the walking beam i i is positioned over the well and has secured to it the polish rod of a string of sucker rods M. This string of sucker rods l4 extendsdownwardly into the well through the pump tubing l5 where it is connected to a plunger of the oil pump (not shown).

Supported in suitable bearings on jack posts I6 is a rotatable drive shaft ll on which is mounted a band wheel l8 driven from a suitable driving means l9 which'may be a steam engine, gasoline engine, or electric motor. Mounted on the end of the shaft I1 is an operating crank 2|] having a crank pin 22, by means of which it is connected to the lower end of a pitman 23. The upper end of the pitman 23 is connected to the left end of the walking beam II. An operation of the drive means l9 rotates the band wheel l8 and the shaft I? which in turn swings the crank pin 22 through a circular path. This operates the pitman '23 which reciprocates the walking beam H and thus reoiprocates the string of sucker rods Hi. The pump plunger is thus raised and lowered and pumps oil to the surface of the ground.

As shown in Figs. 1, 2, and 7, a counterbalance 25 of my invention is mounted on the crank 2|.

This crank 2| is secured by a suitable means including a key 26 to the shaft I! so that it is rigidly secured thereon in a radial plane A--A and so that it rotates on an axis of rotation B. Positioned on opposite sides of the crank 2| are counterweights 28 which are sector shaped, as shown, each including side. faces and an outer curved face. Formed in the inner corners of each counterweight 2B is a pocket 29, and extending into each pocket 29 is a lug or ear 30 which projects outwardly from the side of the crank 2|. Supported by each counterweight 28 is a pivot shaft 3| which extends through the adjacent ear or lug 30 and thus pivotally supports each of the counterweights on opposite sides of the crank 2|. Each counterweight 28 is swingable in the plane of rotation of the crank 2|. The side faces 32 of the counterweights 28 which rest adjacent the operating crank 2| when the counterweights are in extended position are recessed at 33 so that the counterweights may fit around the extending end of the crank 2|.

Formed in the side faces 3d of each counterweight 28 opposite the walls 32 is a pocket 36 through which a pivot pin 31 extends. Placed in each pocket and rotatable on the pivot pin 31 is a bearing 38. Extending from each bearing 38 is a threaded rod 39, each of which extends through a lug or projection 46 formed on the hub of the operating crank 2i. As shown best in Fig. 6, each projection 40 has an opening 4| formed in it which is hour-glass shape so that the rod 39 which extends through it is enabled to swing in a plane parallel to the plane of rotation of the crank 2|. Furthermore, the outer face of each lug 40 is made cylindrical, as indicated at 42, on an axis which extends parallel to the axis of rotation B. Positioned for engagement with each lug m at opposite ends of the opening 4| is a bearing block 43 having a semicylindrical surface adapted to engage the cylindrical surface 32. Threaded on each rod 39 on opposite sides of each of the blocks 43 are looking nuts M whereby each rod 39 may be locked in any desired position with respect to the lug so, and since each lug fill is mounted on the crank 2| each rod 39 may thus be locked. with respect to the crank 2|. It will be noted that the upper ends of the rods 39 cross the axis A-A, and that, therefore, these rods must be olfset as shown in Fig. 3, and that the lugs 10 must also be offset.

The rods 39 and associated parts constitute a means whereby the counterweight 28 may be moved into any position between extended and retracted position and may furthermore be supported in any of the positions into which the counterweights may be moved. It will be seen that the pivots 3i and 37 and the point of the attachment of the upper end of the associated rod 39 form a triangular truss, and that, therefore, each counterweight may be securely retained in the position into which it is adjusted. When it is desired to move either or both of the counterweights 28 into a different position, such, for example, from the position shown in Fig. 2 into the position shown in Fig. 7, the lower nut on each rod is advanced downwardly on each shaft 39 and thereafter the upper nut is advanced downwardly,

thus pulling each rod 39 through the opening M in the associated lug 4%. This causes each counterweight 28 to swing on the pivot 3| and move from a position shown in full lines in Fig. 2 into a position shown in full lines in Fig. 7.. It will be seen that when this movement occurs the pivot 31 is raised relative to the lug it, and therefore the rod 39 is swung into a less angular position with respect to horizontal, as indicated in full lines in Fig. '7, and by dotted lines it: in Fig. 6. In view of the offsetting of the rods and lugs the rods are able to cross a common plane without interference. The outer corner of each counterweight is provided with a slot is through which one of the rods 3t extends when the counterweights are in retracted position.

In order that the weight of each counterweight 28 may be increased or decreased in order to suit the requirements for difierent depths of wells, each weight is provided with a pocket M formed from the side wall 58, thus producing a sidewardly-facing pocket fill defined by a bottom well t9, an outer wall 55], and side and inner walls 5|. Adapted to be placed in the pockets of either or both counterweights 28 are extra weights 52 which may be cored out, if desired, as indicated by dotted lines 53, to control their weight. These extra weights 52 are secured in place by suitable securing bolts 5& which extend through semicylindrical openings 55 formed in the extra weights 52 and in the outer wall til. The securing means 5% only prevents the weights from falling sidewardly from place, and the outer wall 56 of each pocket ll takes the force set up due to the rotation of the counterweight, and thus produces a firm and mechanically safe connection between these parts.

During the pumping operation the counterbalance is supported in counterbalancing position. If a maximum counterbalancing effect is desired,

the counterweights 28 are supported in their 75 outermost position, as illustrated in Fig. 2. If less counterbalancing effect is desired, both of the weights may be swung upwardly with respect to Fig. 2 in order to bring the center of mass of the counterbalance closer to the axis of rotation B. When the counterweights are held in identical positions, such as shown in Fig. 2, the center of mass of the counterbalance is on the radial plane AA, If it is desired to shift the center of mass either ahead or in back of the axis AA, this is done by moving either of the counterweights 28 relative to the other, such, for example, as indicated by dotted lines 58 of Fig. 2.

When the rig is to be employed for purposes other than pumping the pitman 23 is disconnected from the crank 2i and the counterweights 28 are retracted into the position shown in Fig. 7 which may be designated as a neutral or flywheel position. When in this position the center of mass of the counterbalance is substantially concentric to the axis of rotation B.

From the foregoing it is believed that the important features and advantages of my invention will be apparent. It will be seen that the counterbalance of my invention is mounted on the crank 2| and may be adjusted to give maximum counterbalancing action or partial counterbalancing action, to move the center of mass either ahead or to the rear of the center line A-A, or may be moved into a concentric, or neutral, or flywheel position so that the apparatus may be used for operations other than pumping. It will further be seen that the moving of the counterweights 28 into any desired position is very readily accomplished by adjusting the nuts 44 to proper positions on the rods 39, and that when the rods are secured in any given position a rigid attachment is provided. It will furthermore be seen that the weight of the counterbalance may be increased by use of the added weights 52 which may be of any desired weight, this being accomplished by the extent of coring, as indicated by dotted lines 53 in Fig. 4. A further important feature is the positioning of the added weights in sidewardly-facing pockets so that the force produced by rotation of the counterbalance is taken directly against the outer wall 50 of each pocket and is therefore transmitted directly to the counterweight 28 and not through any attaching means, the attaching means being employed solely for the purpose of holding the weights from falling sidewardly from the pockets I claim as my invention:

1. In a counterbalance construction, a rotatable shaft, a crank arm secured to said shaft, a pair of counterweights, means for pivotally mounting said counterweights one on each side of said crank arm for adjusting movements in the plane of rotation of the crank arm, and means for effecting independent adjusting movements of the counterweights about their pivots and for supporting said counterweights during and after adjustment, said adjusting means comprising a rod for each counterweight pivotally connected to the same at a point spaced radially of its pivotal mounting and pivotally and adjustably connected to the crank arm on the side of the shaft opposite the counterweight mounting means.

2. In a counterbalance construction, a rotatable shaft, a crank arm secured to said shaft, a pair of sector shaped counterweights, means for pivotally mounting said counterweights at their apexes one on each side of said crank arm for adjusting movements in the plane of rotation of said crank arm and with the pivots equispaced radially of the shaft, and means for effecting independent adjusting movements of the counterweights about their pivots and for supporting said counterweights during and after adjustment, said adjusting means comprising a rod for each counterweight pivotally connected to one edge portion of the same at a point spaced radially of its pivotal mounting and pivotally and longitudinally adjustably connected to the crank arm on the side of the shaft opposite the counterweight mounting means.

3. In a counterbalance construction, a rotatable shaft, a crank arm secured to said shaft, a pair of sector shaped counterweights, means for pivotally mounting said counterweights at their apexes one on each side of said crank arm for adjusting movement in the plane of rotation of Said crank arm and with the pivots equi-spaced radially of the shaft, and means for effecting independent adjusting movements of the counterweights about their pivots and for supporting said counterweights during and after adjustment, said adjusting means comprising a rod for each counterweight pivotally connected to one edge portion of the same at a point spaced radially of its pivotal mounting and pivotally and longitudinally adjustably connected to the crank arm on the side of the shaft opposite the counterweight mounting means, each of said counterweights having a cut-away portion to provide clearance for the rod of the other counterweight while said counterweights are in certain positions of adjustment.

4. In a counterbalance construction, a rotatable shaft, a crank arm secured to said shaft,' a pair of counterweights, means for pivotally mounting said counterweights one on each side of said crank arm for adjusting movements in the plane of rotation of the crank arm, and means for effecting independent adjusting movements of the counterweights about their pivots and for supporting said counterweights during and after adjustment, said adjusting means comprising a rod for each counterweight pivotally connected to the same at a point spaced radially of its pivotal mounting and pivotally and adjustably connected to the crank arm on the side of the shaft opposite the counterweight mounting means, said rods lying in parallel planes to allow for crossing of the same during certain positions of adjustment of the counterweights.

5. Ina counterbalance device of the character described, the combination of: a crank arm adapted for use with a rotatable member; a pair of counterweights; pivot means connected to said crank arm intermediate the ends thereof and supporting said counterweights one on each side of said arm so as to swing into different counterbalancing positions relative to said arm; and means for effecting independent adjusting movement of said counterweights about said pivot means and for holding said counterweights during and after adjustment, said adjusting means comprising a rod for each counterweight, two pivotal connections for each of said rods, one of said connections attaching said rod to a counterweight at a point spaced radially from said pivot means, and the other of said connections attaching said rod to said crank arm, one of said connections having means for eifecting adjustment of the pivot axis of the connection along said rod to thereby change the effective length of said rod so as to swing the counterweight associated therewith on said pivot means.

6. In a counterbalance device of the character described, the combination of t a crank arm adapted for use with a rotatable member; a pair of counterweights; pivot means carried by said crank arm intermediate the ends thereof and supporting said counterweights one on each side of said arm so as to swing into different counterbalancing positions relative to said arm; and means. for effecting independent adjusting movement of said counterweights about said pivot means and for holding said counterweights during and after adjustment of said adjusting means, said adjusting means comprising a threaded rod for each counterweight, two pivotal connections for each of said rods, one of said connections attaching said rod to a counterweight at a point spaced radially from said pivot means, and the other of said connections attaching said rod to said crank arm, one of said connections comprising a head secured to the part to which it connects said rod, said head having a diametral opening through which said rod passes, and nuts on said rod on opposite sides of said head whereby rotation of said nuts on said rod will efiect adjustment between said head and said rod and swing said counterweight associated therewith on, said pivot means.

7. In a counterbalance device, the combination including: an. arm adapted to be secured to a rotatable member; a pair of counterweights, one positioned on each side of said arm; means supporting said counterweights on said armv so that they are movable into diiferent counterbalancing positions relative to the axis of rotation of said arm; and means for moving said counterweights into said different counterbalancing posito a rotatable member;

tions comprising a strut for each of said counterweights arranged at all times at an angle to the length of said arm and two pivotal connections for each of said struts, one of said connections attaching said strut to a counterweight at a point removed from said counterweight supporting means, and the other of said connections attaching said strut to said arm, and means for effecting adjustment oflthe pivot axis of one of said connections along said strut to thereby change the effective length of said strut and move the counterweight associated therewith relative to said arm.

8. In a counterbalance device, the combination including: an arm adapted to be secured a pair of counterweights, one positioned on each side of said arm; means supporting said counterweights on said arm so that they are movable into different counterbalancing positions relative to the axis of rotation of said arm; and means for moving said counterweights into said different counterbalancing positions comprising a strut for each of said counterweights arranged at all times at an angle to the length of said arm and two pivotal connections for each of said struts, one of said connections attaching said strut to a counterweight at a point removed from the counterweight supporting means, and the other of said connections attaching said strut to said arm, and means operatively associated with said strut to vary the distance between the pivot axes of said pivotal connections to change the effective length of said strut and move the counterweight associated therewith relative to said arm.

WARREN M. MANSFIELD.

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