US2348241A - Oil well pumping means - Google Patents

Description

May 9,1944-l c. E. BRlDwELl. 2,348,241

OIL WELL 'PUMPING 'MEANS Filed Aug, 2e, 1941 4 sheets-sheet 2l INV ENT OR.

CHALON E. QR/DWELL BY ammi., H/` ATTORNEY May 9 1944 L c. E. BRIDWELL 348,241

OIL WELL PUMPING MEANS /sa nsfl l 14a INV ENT OR.

CHA/ 0N E.BR/DWLL BY aaoud@ H/s 'ATTQRNEY v Patented May 9, 1944 UNITED STATES PATENT OFFICE on. WELL PUMPING MEANS Chalon E.Bridwell, Detroit, Mich. Application August 26, 1941, serial No. 408,366

I12 claims.`

' My invention pertains to improved pumping apparatus especially useful for pumping oil-wells and having improved features also advantageous for use in various oil field equipment.

It is an object of my invention to provide anA improved bearing for pumping apparatus which provides greater bearing surface Within more compact dimensions, which vmay be used horizontally or vertically in various apparatus, which will retain the lubricant yand control end play or side slap, and which Vwill be convenient and economical to manufacture, install and maintain.

It is also an object of my invention to provide oil-well pumping apparatus of a simple rugged construction which is conveniently retractable for servicing the well.

It is a further object of my invention to provide oil-Well pumping apparatus having an improved equalizer over-arm driving arrangement.

Further objects and advantages are within Ythe scope of my invention, such as relate to the arrangement, operation and function of therelated elements of the structure, to various details of construction and to combinations of parts, elements per se, and to economies of manufacture and numerous otherffeatures as will be apparent from a consideration of the specication in conjunction with the drawings disclosing specific embodiments of my invention, land in which:

Fig. 1 is a side elevational view of an oiL-well and pumping unit arranged in accordance with the invention;

Fig. 2 is an enlarged fragmentary side elevational view showing the retractable mounting lwhereby the walking-beamis pivotally journalled on threaded bearings and retractable link arms;

Fig. 3 is a cross sectional view thereof, as indicated by line 3-3 in Figs. 1 and 2;

Fig. 4 is an enlarged fragmentary sectional View taken through the` end ofthe main bearing Ablock and shaft on line 4-'4 in Fig. Zito` show bearing details; A

Fig. 5 is a side elevational view showingthe walking-beam and link arms turned backtoretracted positilon to 'clearthe well for servicing;

Fig. 6 is an enlargedside elevational view showing a diierent embodiment comprising a single retractablelink arm for pivotally supporting the Walking-beam;

Fig. 7 isa cross sectional view on line lf-1 of Fig'. 6iY f VFig..8 is a side elevational view show-ing still anotherembodiment of retractable link arm for pivotally supporting the walking-beam, shown broken away;

Fig. Sis a plan view thereof;

Fig. 10 is a cross sectional view on line Ill-I0 of Fig. l9;

Fig. 11 is a'cross-sectional-view taken through the Walking-beam on line II--II in Fig. 1, and showing the equalizer over-arm driving connection; i Y

Fig. 12 is a sectional view on line I2-I2 of Fig. 11.

Fig. 13 is a sectional `view on line I 3--I3l of Fig. l1.

Fig. 14 is a side elevational view showing a dif- -ferent embodiment utilizing my threaded bearing for pivotally supporting a walking-beam; and

Fig. 15 is a cross sectional view on line I5-I5 in Fig. 14.

Referring more particularly to Fig. 1 of the drawings, I have shown an oil-well pumping outfit comprising a wa-lking-beam II which is pivotally journalled upon the extended end of retractable link arms I3 the other ends of which are pivotally supported upon the upper end of a Samson post I5 so that'the entire walking-beam may be conveniently and quickly retracted to clear the well for servicing, in a manner to be subsequently described.

The VSamson post, which may be any type of ytripod or other up-right structure useful for such a purpose, is shown as a verticalV post I5 `which may be a rolled steel structural member of I crosssection resting at vthe lower end upon a horizontal I-beam I1 extending transversely vover and between two horizontal l3beams I9 disposed in horizontal spaced: relation and which may be -joined by suitable cross pieces (not shown) for forming a base frame, in a usual manner. The ASamson post I 5 is braced by means of an inclined angle iron l2I the upper end of which may be welded to the post from which it inclines diag- Y onally down, the lower end being secured to the base frame. The base frame, V-of any suitable construction, may as usual rest upon a concrete foundation 23 `above ground level adjacent vthe oi1wel1casing25 and head 21.

VFrom the oil-well casing the upper end of the polish vrod 29 rises for attachment tothe lower end of a steel cable 3l by means of Aa clamp 33. The cable 3| extends up 'and connectsto an arcuate horses head 35 on the well vend of the walking-beam II, which may be `reinforcedfby a -brace 36 in a more permanent construction as it does not have tol be removed'and` the center of the lcurvature of the Varcuate portion 3'1 coin- .purpose. `bers; having inwardly extending flanges 59v to provide lateral rigidity and` being cored out betainer ring is. firmly clampedagainst the outside cides with the center of the pivot shaft 39 which supports the lower ends of the link arms I3 on top of the Samson post. In this manner, the cable 3| is raised and lowered in alignment with the Well casing 25 as the walking-beam II is rocked. The walking-beam is oscillated by unit 4| on base frame remote from the well and connected to the other end of the walking-beam as by a pair of pitman rods 43 actuated from cranks 45 on the driving The driving device,4l .may be4 a geared speed' r'edncing. unit driven; by'. av belt "41 extending to any suitable power source (not shown) in accordance with the usual practise.; u

Y allyjournalled and suspended between the upper The upper ends of the driving pitmans 43 connect to the ends of an equalizer over-arm-'IISI which is journalled transversely uponagjthreadf` ed bearing shaft 5I on the Walkinglbeam'- with one end projecting on each side thereof, in a" manner and for a purpose to be more fully .de-

scribed.

' Counterbalancing weights 53 arel provided; in a usual manner, upon the end of :the Walkingbeam II remote from the well. .'I'heicounterbalancingweights 53'mayV be ofY any conventional construction and may be of a generallyA U shape disposed to straddle the .beam so that weights Vmay vbe conveniently added or removedtoprovide suitable Weighttfor balancing the weight of the sucker rods suspended in the Well from ,the

other end of Athe walking-beam. lAngle iron `walking-beam vupon a retractable flink arm arrangementwhereby. it'may be quickly andconvenientlyretracted toclear the wellwforservicing.' An installation embodying both of these useful features isshown in Figs. l, 2- and 3.

The walking-beam is mounted betweenthe 'pair Vof-link arms- |3 which are heavy members being either of a cast or fabricated construction having suflicient'strength and rigidity for this The link arms I3 may be cast memtween, as represented ibyl dotted lines in Figs. 2 and-3, to. eliminate excess metal and weight.

-Both ends of both link arms I3 are cast with hub portions 6I having apertures for receiving the ends of massive shafts, -39 and 39' which eX- Y tend therethrough. Theends of the heavy supprovided with outwardly projecting portions x65.

of reduced diameterfthreaded forreceiving a nut 611securing-a retaining cup or ring 69 there-- on. Y An inwardly directed flange 1I ofeachreof each adjacent hubV on the link arm.

Before being securedbetween the link arms I3, the intermediateportion-of the Vupper shaft 39'1- is journalled'in an upper, bearing block 13 andthe intermediate portion of the lower Shaft is; iournailedin a lower .bearinablock 1.5..- Mounting lugs 11 extend laterally from opposite sides of the bottom of the upper bearing block for attachment to the upper flange of the I-shaped walking-beam I| in any suitable manner, as by bolts 19 passing therethrough. The lower bearing block is similarly provided with lugs 11 and bolts 19 are passed through these lugs and suitably aligned holes in a base plate 8| to rmly mount the lower bearing block thereon. The base`v plate 8| is firmly attached to,- the upper end of thejSamson'post I5 vinany suitable manner, as by welding for example.

; In this manner the walking-beam II is pivotendsvof the two link arms I3 and the lower ends of the link .arms are pivotally supported on the i shaft 39 in the bearing block 15 on the upper endof the Samson post. Through suitably conlt'rolsV side slap.

-of carrying heavy loads,

nected vgrease ttings 83, which may be of a type known as Alemite or Zerk, lubricant may bev injected into the bearingsunderhigh pressure. f

The journalled intermediate portions ofthe shafts 39 and 39"ar'e.provided withscrewV threads which proj ect in intertting relation into correspondingv threads 85 provided in the associated'bearing blocks 13 and,15. -The root'diameters of the'threaded intermediate portions of size. vHardening'and grinding is eliminated and production is cheapened. The threaded bear- -ing also. serves to retain the lubricant and distributes it slowly and uniformly around the bearing surfaces as the members oscillate. Also the threaded bearing sustains end thrust and con- My threaded bearings may be used for supporting members for oscillation either on'a vertical or a horizontal axis.

Eachspacer ringis provided with a thin annular `grease retaining flange 89 which extends in to an annular groove 9| provided in the respective adjacent ends of the bearing blocks 13 andg15,

asV may be seen more clearly inlig.' 4. Each shaft is also preferably provided with a shallow annular groove 93 inside of the flange' 89 of each spacer-ring. The threads 85.` andy 85'V on the shafts and bearing blocks aregmachined with proper clearance to allow theilubricant-to work zthrough, vand the surplus overflow' of thegrease 95 lodges and forms a seal between the ends of the bearing block and the adjacent spacer ring, asV shown in. Fig. 4,- an enlarged fragmentary sectional view. In this. manner the'fbearings are sealed and protected to retain the. grease and to exclude dust and foreign mattergbeingcapable and providing 'long-bearinglife. 1.1;'YV v A bearingrest V91 secured to theibottomof the Alowerflange ofthe I-beam II, as by bolts99, is

suitably shaped and g positioned .-to t 'overythe lower bearing block 'I5 in normal operation..V The bearing rest 91 has downturned ends IIJIwhich fit andrest upon the spacer rings at the ends of the bearing block. One of these downfturned edge'-I'whilrfltsnio a corresponding beveixed groove in the adjacent spacer ring, where it rests at all times during normal operation.

As the walking-beam oscillates back and forth through a small angle While pumping the well, the-rotation takes place entirely between the lower shaft 39 and the lower bearing block 15 in which it is journalled. The twolink arms I3 merely rock with the walking-beam during pumping operation, and there is no rotation in the upper bearing.

To servicethe well, the walking-beam is conveniently movedto a retracted position, vas shown in Fig. 5, the polish rod being disconnected 'from the usual connection with the horses head. This is accomplished by attaching a hoist (not shown) to the lifting ring |91. and lifting the walking- Vbeam and turning it and the link arms back, as

lthe bottom of the walking-beam merely rests directly upon the top of the lower bearing block while the well is being serviced. After the servicing of the well has been attended to, the walking-beam and the supporting link arms are again turned toward the well t-o normal operating position.

Figs. 6 and 'l show another embodiment of my quickly retractable mounting for the walkingbeam I'I, wherein only a single llink arm I I is provided, being a cast or fabricated structure of suitable strength and rigidity for the purpose. The upper end of the link arm is provided with a rigid stub shaft I I3 one end of which extends laterally and is journalled in a bearing block |`|5 secured by bolts ||6 to the upper side of the walkingbeam. 'I'he lower end of the link arm I is provided with a stub shaft ||1 which is journalled in a lower bearing block ||9 mounted on the upper end of the Samson post I5, as in the previous embodiment. The shafts ||3 and ||1 may be either integral with the link arm I I I or may be inserted and keyed therein, as desired. On the end of each bearing block remote vfrom the link arm a grease cap |2| is firmly secured, as by screws |23, and by means of suitable grease viittings 53 therein lubricant may be injected under high pressure into the ends of the bearings to gradually circulate therethrough around the oscillating shafts II3 and ||1. As in the previous embodiment, the shafts are .provided with screw threads cooperating with suitable clearance in intertting screw threads in the bearing blocks and the screw threaded bearings having the same useful purposes and advantages as previously described. Y

An annular packing groove is provided in the end of the lower 'bearingblock ||9 adjacent the link arm and concentrically positioned with reference to the shaft ||1 for receiving the -edge of a cylindrical dust ring |21, the other end of which fits snugly ont-o a cyl'indrica] shoulder |29 provided on the link arm. Packing |3| -isprovided in the packing groove |25, and this assembly serves to retain grease and exclude dust, rain and foreign matter from the'lower bearing, which is the one Vwhich oscillat'es during well pumping operation. If desired the upper bearing may be similarly enclosed and protected.

Projecting from the side of the link arm adjacent the lwalking-'beam is 'a walking-beam rest V|33 which is of asemi-circular shape, as may be seen in Figs. '6 and'l, "with'the -curved side |35 a 3 may be attached by Welding or in any suitable manner. lAs may be seen, in Fig. '7, and dotted in Fig, 6, the portion of the curved surface |35 vwhich receives the walking-beam is of a smaller diameter and the end portions are of larger diameter providing end flanges or guides |31 for properly positioning the bottom of the Walking-beam upon the rest in either inclined position of the link arm. The single link arm I I with pre-assembled shafts II3 and ||1 is a simple structure facilitating transportation and installation in the field.

Assuming that, as shown in Fig. 6, the walkingbeam III is in the direction toward the well and is operating, it remains continually against the beam rest |33 and the link arm rocks with the walking-beam, all the rotation or oscillation taking place in the lowerbearing block ||9 on top of the Samson post or upright structure. To service the well, the walking-beam is raised and the link arm I I as viewed in Fig. 6, is turned'up vertically and then inclined 'toward the right hand side to a position, as indicated by the dotted center line. In this position the bottom of the walking-beam again firmly engages the beam rest |33, but on the left hand side thereof, and the walking-beam is shifted to the right by a distance equal to the 'displacement of the shaft I3 in the upper end of the link arm. The well is thus kconveniently and quickly cleared for servicing.

Figs. 8, 9 and 10 disclose 'a simplified embodiment of retractable mounting rso arranged that the walking-beam may be quickly and conveniently retracted for servicing the oil well. A pivoted link |4| is providedwhich is a generally Y-shaped member .hav-ing the lower or stem end thereof apertured to provide a bearing |42 jou-rnalled on the intermediate portion of a stationary shaft |43. The shaft |43 and its bearing aperture in the center bearing |42 of the link, are provided with cooperative screw threads |45 asprovided in: the previously described embodiments. The ends of the shaft |43 are secured in apertures in two spaced upright standards |41 rising from 'a bracket plate |49 which is secured by bolts |5| to the top plate 8| 0n the Samson post. I5. The spreading arms |53 of the Y-shaped link member |4I carry a shaft |55 vextending therebetween and passing through a bearing block |51 which is secured on the bottom side of the walkingebe'am as by bolts |59. The shaft |55 'and the ,bearing block |51 are also preferably provided with cooperative screw threads, although in pumping operation the oscillation takes place entirely upon the shaft I 43 in bearing on Samson post, the link |4I oscillating back and forth with the walkingbeam As shown in Figs. A8 'and 10, the 'stem or pivoted end 42 of the Y-shaped link member is provided with a pair of guide lugs 48 projecting in spaced relation for receiving 'and engaging opposite sides of the walking-beam.

Suitable grease fittings 83 are provided for injecting lubricant under pressure into the 'threaded bearings. The shaft |43 is secured stationary .in the bracket |41,as by a screw passed through an end flange 16| into the bracket. IIhe shaft |55 is secured to the link structure |4| bya screw |63 passed through an -end flange |65 on the shaft and into the link member.

Assuming that the Walking-beam, as Shown -in Figs. 8 and l0, is in the position toward the :well for pumping operation, it`may be retracted away from the well merely by lifting the walkingebeam as by a hoist (not shown) connected to the 'Flirting ring fl s'a, turning the vimi: am 114| and,

' nected thereto.

lines.

Figs. 11, 12 and 13 show the arrangement of ythe equalizer over-armrrfor applying equalized driving forces to the walking-beam from the pitmans, the upper ends ofwhich are pivotally con- An over-arm` 49 is provided, which is a cast or fabricated Vmemherof suitable strength lor, rigidity, and prefera'blyformed vwith a solid central section and the end portions extending therefrom are substantially hollow, being open from the bottom to provide maximum strength and rigidity with minimum weight and material, as shown by dotted lines in Fig. 1l. The over-arm is vpivotally `journalled upon the intermediate-portion of 'a shaft 5| which passes through a bearing aperture in the center of the over-arm and parallel tolthe axis of the walking-beam.. The shaft |1is mounted on top of the walking-beam in axially parallel relation thereto so that the ends of the over-arm 49 extend transversely to opposite sides of the walking-beam; For this purpose, vthe ends of the shaft 5| are rmly secured and supported in a pair of brackets |1| secured on the top ofthe walking-beam, as by bolts |13 Vrpassing therethrough. L'

In accordance with my invention, I provide a screw thread on the shaft 5| which interts a corresponding screw vthread in the bearing aperture in the walking-beam 49. The ends of the shaft 5| are secured firmly in the brackets |1| in any suitable Amannery which is facilitated by threading the shaft full length and providing corresponding threads inthe shaft apertures in the brackets. VThe shaft is firmly secured in one of the brackets' |1| in any suitable manner, as by a screw |15 passing thereinto through a lateral end flange |11 on the shaft, so that the overarrn oscillatesY onv the shaft, the latter being stationary relative on the walking-beam. A high pressure grease fitting |19 is provided on the over-arm for injecting lubricant under high pressure through aipassage |8| into the threadedv bearing.

The overhanging endsvof the over-arm 49 each comprise two spaced bearing lugs |83 extending downwardly for supporting a shaft |85 therebetween substantially parallel to the axis of the walking-beam. A universal bearing member |81,

fwhich is journalled on the intermediate portion of each shaft |85 between the lugs, is suspended downwardly for pivotal connection with the upper ends 'of the pitmans 43. Each shaft |85 and its bearing in the' universal number |81 are provided withcooperative screw threads. A lateral ange |89 is provided on the end of each shaft |85 for securement by a screw |8| -passing therethrough. into`the adjacent lug. Each pitman 43V is provided with a screw threaded shaft |93 projecting laterally from the upper end of the pitman intoa threaded bearing aperture passing through the lower endv of the adjacentuniversal member |81. The other end of the threaded aperture in the universal member is closed by means of a grease plate |95 secured by screws |91 and provided with a grease fitting |99 through whichlubrioant under high pressure may be injected into the bearing. During each stroke of the pitman 43 to oscillate the walking-beam, the threaded pitman shaft |93 oscillates in the threaded aperture in the universal member |81 As a result .greasegradually works through and a small vquantity escapes from the walking-beam end adjacent the pitman 43.v To hold the grease and exclude dust, a felt packing ring 20| is provided on the pitman shaft |93 in the space between the universal member |81 and the pitman. Felt washers may be similarly provided on the over-arm shaft 5| in the spaces between opp f'isite sides of the'over-armf44 and the brackets .In operation the yequalizer over-arm 4911iclines slightly to one side or the' other to compensate for any slight misalignment of the cranks 45 on the driving device relative to the driven end of the walking-beam. Also this arrangement hasspecial utility in compensating for any misalignment Ywhichv might Ibe caused by sidewise ivmentt of; the walking-beam as it oscillates enis Wo eX reme si' the Wen. po tions for pumping Figs. 14 and 15 show the application of the improved threaded bearing in an unretractable walking-beam mounting comprising any conventional ySamson post structure such as vertical beams 203 and angular braces 205 welded together at the upper to a top plate 201. On top of the top plate 201 a pair of shaft brackets 209 are secured in spaced apart relation, as by welding or in any suitable manner, for securing and supporting the endsof a. shaft 2|| extending therebetween. At one end the shaft 2|| terminctlls (inba lateral lazilige or head 2|3 which is s e y a screw 5 assin n cent bracket. p g i to the adm A lbearing block 2|1 is journalled on the intermediate portion of the shaft 2|| for supporting the Walking-beam I I, which is secured thereon in anysuitable manner as -by welding, for example. A substantial amount of clearance space must be provided lbetween the opposite ends of the bearing block 2|1 and the brackets. 'I'he intermediate portion of the shaft 2|| and the bearing block 2|1 are provided with intertting screw threads which cooperate in the same manner to provide the same useful advantages which were explained previously with reference to the retractablevniountings. In each clearance space on opposite sides of the bearing block 2|1 a dustproof felt sealing ring 2|9 is provided to retain grease and exclude d ust and foreign matter. A grease fitting 83 on the bearing block 2|'I provides for injecting lubricant into the bearing through a passage 22 I.

It will be seen that I have provided an irnproved bearing which provides greater bearing surfaces within given dimensions for pivotally Journalling oscillating members and which effectively retains and uniformly distributes lubricant f orvlong bearing life with a minimum of attention. The improved bearing also supports en'd thrust and controls side slap and may be utilized' in various positions either on a vertical or a horizontal axis and in addition to journalling'walking-beams it is also advantageous for use in horizontal swings in the rod line forpumping one Wellfrom another, in rod line holdovers o r universal ypendulums, stroke posts, and the like. The retractable mounting for walkingbeams, that providesconvenient servicing, may be a unitary or a fabricated link member.

It is apparentthat within the scope ofthe yinvention modifications and different arrangedue to relative 'rotation of the walking-beam. 7| the invention comprehending variations thereofo I'claim: M 1 w 1. Retractable oil-well pumping apparatus having in combination, las stationary :ibase-,na Samson post mounted on saidbase, a link arm, bearing means journalling one 'end of said link armwup'on Vthe upper end of? said postwith kthe other end extending; therefrom to. befturnedto either anoperative position or to a retracted 'position, a walking-beam, bearing means `journalling said walking-beam upon the extended.. endaof said link arm, and means for oscillating said walking-beam and link arm together in a predetermined angular relation.

2. Retractable oil-well pumping apparatus comprising, a stationary base, a Samson post, a link arm, bearing means journalling one end of said link arm upon the upper end of said post with the other end extending therefrom, a walking-beam, bearing means journalling said walking-beam upon the extended end of said link arm for disposition either to an operative or to a retracted position, the link arm and the walkingbeam being in predetermined relative angular relations both in the extended position and in the retracted position, and means for simultaneously oscillating said walking-beam and link arm together in a predetermined angular position.

3. In combination in retractable oil-well pumping apparatus, a base, an upright structure on said base, a link member, bearing means journalling one end of said link member upon the upper portion of said upright structure with the other end extending therefrom, a walking-beam, bearing means journalling said walking-beam upon the extended end of said link member so that the link arm and the Walking-beam may be oscillated together in a fixed angular relation or conveniently turned to a retracted position in a different angular position, said bearing means comprising interfltting screw thread portions providing extra bearing surface and limiting side slap, and means for oscillating said walkingbeam and link member.

4. Retractable oil-well pumping apparatus comprising, a stationary base, an upright Samson post structure, a link arm, a shaft projecting laterally from each end of said arm, bearing means journalling one of said shafts upon said structure with the link arm extending pivotally therefrom, a walking beam, bearing means journalling said walking-beam upon the shaft on the extended end of said link arm, and a beam rest on the intermediate portion of said link arm for engaging the beam when it is turned in either direction from perpendicular toward parallel relation with the link arm.

5. In combination in retractable oil-well pumping apparatus, base supporting means, an upright structure rising from said base, a pair of link arms disposed in spaced parallel relation, a pair of shafts each having the ends thereof secured in and between adjacent spaced ends of said pair of link arms, bearing means journalling one shaft upon the upper end of said upright structure with the other ends of the link arms extending pivotally therefrom, a walking-beam, bearing means journalling said walking-beam upon the shaft between the extended ends of said link arms for oscillation together therewith, a bearing rest secured on the bottom side of the walking beam, said bearing rest being suitably shaped and positioned to fit over the first mentioned bearing means during normal oscillating operation of the walking-beam and conveniently separable therefrom as the walking-beam and link arms are shifted to tilt away from the well in retracted position.

6. Retractable oil-well pumping apparatus Y in accordancewith claim 5, and said second mentioned bearing means being secured to the upper side of said walking beam. y 7. .In combination in retractable oil-well pumping` apparatus, base supporting means,'an upright structure rising Afrom said base, a pair of linkv arms disposedjin spacedparallel relation, a pair of--shaftsfeach having the4 ends thereof se'-r cured in and-.between :adjacent spaced; ends of said pair of link arms, bearing means journalling one shaft upon the upper end of said upright structure with the other ends of the link arms extending pivotally therefrom, said shaft and said bearing means having screw thread portions cooperatively intertting therebetween, a walking-beam, bearing means journalling said walking-beam upon the shaft between the extended ends of saidlink arms for oscillating together therewith, said bearing means being secured to the upper side of said walking beam, a bearing rest secured on the bottom side of the walkingbeam, said bearing rest being suitably shaped and positioned to nt over the first mentioned bearing means during normal oscillatory operation of the walking-beam and conveniently separable therefrom as the Walking-beam and link arms are shifted to tilt away from the well in retracted position.

8. Retractable oil-well pumping apparatus in accordance with claim 4, and said second mentioned bearing means being secured to the upper side of said walking-beam.

9. Retractable oil-well pumping apparatus comprising, a stationary base, an upright Samson post structure thereon, a link arm, a shaft projecting laterally from each end of said arm, bearing means journalling one of said shafts upon said upright structure with the link arm extending pivotally therefrom, said shaft and said .bearing means having screw thread portions cooperatively intertting therebetween, a walking beam, bearing means secured to the upper side of said walking beam and journalling the walking beam upon the shaft on the extended end of the link arm, and a beam rest on the intermediate portion of said link arm for engaging the lower side of the walking beam when it is turned in either direction from a perpendicular toward a parallel relation with the link arm.

10. In retractable oil-well pumping apparatus the combination according to claim 5, an equalizer arm, bearing means journalling said equalizer arm on the upper side of said walking-beam with the ends of the arm projecting on opposite sides of the walking-beam, a driving device having transversely disposed crank means, a pair of pit-- man rods, means connecting an upper end of each pitman rod pivotally to a projecting end of said equalizer arm, and the other ends of said pitman rods being pivotally connected to said transversely disposed crank means.

11. In retractable oil-well pumping apparatus the combination according to claim 7, an equalizer arm, bearing means journalling said equalizer arm on the upper side of said walking beam with the ends of the arm projecting on opposite sides of the walking-beam, a driving device having transversely disposed crank means, a pair of pitman rods, means pivotally connecting one end of each pitman rod to one end of the'equalizer arm and the other end of each rod to the crank means, and the bearing means journalling the ing means having screw thread portions intertting between the relativelyl moving parts, a walk- A ingbeam, 4means pivotally mounting the walking-beam betweenthe extended arms of the link for disposition either in a pumping position or' in a retracted position on the uprightrstructure, and a pair of guide lugs projecting in spaced apart relation from the stem of the link member for receiving and engaging opposite sides of the walking-beam. v CHALON E. BRIDWELL.

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