US2363552A - Pull rod carrier - Google Patents

Description

p *T-UNITED STATE Patented Nov.,28, `1944 i f i from, RonoARRIER @nnen Rossmmwilmettelnl. ApplieattnMareh 1o, 194i,` seralNo. 382,474

' A ,15claimsl (ciu- 1522er @This invention relates topull rod carriers,` ,and t more particularly to carriersof the type shown in my pending `application, Serial No. 272,865.

i In :certain oil well districts horizontally` recipe.` rocating` pull rods are usedfor transmitting power frornaicentral` enginelor power to each ofa plu;-` rallity` of` pumpsjsomeof whichmay `be thousands `of yfeet distantffrom `the power. Each .pull .rod

which extends from the` power to a pump.` is supi ported` by `carriers every. twenty-five or so feet` in order `to prevent excessive sagging of the pull rod or to prevent dragging on thejground.

neverwinf tension. The `Wear on the bearings is therefore alwaysin the same directiof` and can thus be readily taken up after considerable wear has occurred. Also, even beforeitheiwear is taken up `'there willbe no back lashas thecarrier oscillatesffrom` its'center positionztojeithertextreme `position,.`since the direction of the stressin'each link remains the same throughout the cycle1o`f The pull rodcarrier 'of the `type withwhichthe present inventionirelates` compris/esa. linkage pivoted 'about two stationaryi pivots and having one pointthereof which `moves `in substantially a straight horizontal line;` A-pull .rod support is mounted on the carrier atythegstraightline motionI point thereof, `and the `pull rod rests upon that supportjAs the pullrodreciprocates it causes the pullxrodj` carrier to swing `with it, and` guides it in subatjone` end about spaced `parallel axes andinter-1 connected,` at` their opposite ,ends bya third link.

,Apoint on the perpendicular bisector of the third` link movesin a straight line. `liaedtosupportthe pull rod. p

This `peint is auf 1 In; my; application i Serial No. 272,865, above 3referredutd the arms` are "made `ofi considerable length sothat the straight line `motion point of the mechanismwill lie above the stationarypivots of the arms. In this type. of Roberts mechanism,`

`when the pull rodireaches one extreme position,l 4

all of` the weightonthecarrier is imposed upon one of thearms1and,z in. addition, `that `one arm exerts ya tension on the otherarm. Each arm is `thus lfunden` compression'` duringthe major por--l -tion of the stroke andunder tension at one end` ofthe stroke. a result the Wear on the bearings fis at the top and at thebottomof` the bearing.` Afterthere has been some wear in the bearings play .:develops' due to back lash as the stress on a link` or armfgoesfrom compression ,to` tension. ItV is oneA of the objects` of the present. invention to overcome this difliculty by using a Roberts `type lof `mechanism which isso proportioned that the Supporting arms are 1always in` compression and Figure is an end view thereof;`

movement of the pull rod. i Y i L i Itis a further object `of the presentinvention toprovide a `pull rod carrier `of `theabove-.menf H tioned character with a simple typeof bearing support which will allow a quick assemblypf ythe carrierin the field. `Itis a still further object of the present invention to provide `anirnprove`- l` carrier` ofthe above mentioned character wherein the arms are comparatively `short thus reducingthe l amount of material required for the carrier.` and alsofreducing the momentum of the moving parts byreducing their` mass.` z' f 1 x l It is a still further 4object ofthe presentin-Y vention to provide anwimproved carrier of the above` mentioned characterwhereinfthe carrier supporting base acts `as a stop tolimit the motion of the carrierin each directionwithoutthe addition ofl material to the `base for, accomplishing` the stopping' function. f f* The attainment ofthe above and lfurtherfolzv jects lof the present invention Vwill beapparent 30 `from `the following specification taken in con-` VjunctionV .with the i accompanying drawing forming a part thereof.; l `j i t i. v In vthe drawing?` f u Figure 1 isy a plan View of acarrierembodying the `present invention;

.Figure `2 `is a front `view of the `uren? i carrier of" Fig- Figure 4is'a fragmentary perspective `the carrier of `Figure 1; and

i Figure 5 is a perspectivedisassembled viewof the pullrod support of the carrier of Figure 1.

Reference may now beV had more particularly to the drawing,` wherein like reference` numerals y `designate like parts throughout. `Afpullrod car- 3rier which isindicated at lisupportsa pullrod i `2thatreciprocates horizontally. `The pull rodi 2 is oneof a numberof pullrodseach extending from :a sourceof power `to differentpumps `in an i oil` fieldncSome pumps are `comparatively ,closel Ito :the power andnothersimay be thousands of feetaway.` :The `pull rod 2 is supportedQat regular,V intervals, `approiimat`e1y\twenty--five feet apart,

`by carriersisuchasthe 'carrier "The carrier is viewof theflower end Aof oneof the supportingarms of" This asthe pipe 6. A short second rod I0 is also welded to the pipe 6. The U-bolt 8 embraces the post 4 and extends through the holes in the pipe 6,

and is secured in place by nuts II threaded on the U-bolt and bearing against the rods 9 and I0. The U-bolt thus rmly secures the support-y ing rod 9 to the post 4. The supporting rod .9.

is bent at its opposite ends to form arms. I2-I3 constituting pivot rods or bearing supports. A pair ofxspaced'washers 'I4-I5 are .spot welded to each bent portion of lthesupporting rod `9. The space lbetween each set lof washers I 4-I 5 consti# tutes' a-bearing support. i

Arms 1r-nuke n-Ia of a straight une eper- 'ating mechanism are each supported by the bent portionsfof .the supporting rod between the wash- .ers .I4-'15. The armsor links I1 and I8 are of identical size and construction.` Each armcomprises two wooden boards 2IJ-.2I .secured together l in .spaced relationship by rectangularbearing blocks.V "The upper bearing block, indicated at 22, is .merely an oil soaked hard wood block having .a longitudinally .extending hole therethrough which forms a'bearing. lThe upper bearing block l is bolted to the" boards -2I by two bolts 24 that extend through the boards and through the bear- 'ing' block 22. The lower .bearing block, indicated at 2.6,.c'omprises an oil soaked hard wood block having `a longitudinal slot 21 therein, the top of which slot. terminates in asmooth circular curve 28. vThe lower vbearing block in4 secured between the arms 20-2Iby .two bolts 30 that pass through the boards 2U-2li and through the arms 3I-3I -of the bearing block 26. l

Ail-shaped link pivotally connects the arms I1-I8. This link comprises a steel rod bent to Z-shape so that ithas parallel arms .S6-31 joined by the diagonal' portion 38 of the Z. Washers 4II4I are spot welded to Athe arms 3.6-3.1 respectively. The Z-shaped link includes' 1a depending rod 42 welded to the portion 38 .at the center thereof. The rod 42 is at a slight inclination to a vertical plane determined by the llongitudinal axis of the pull rod 2,v as may be seen from Figure 3.. At its lower end the rod42 has a .short steel rod or` stem 43 welded thereto and extending horizontally therefrom. The stem 43 has a. pair of .spaced washers 44-45 mounted thereon and spot welded thereto. wood block 46 is slipped over the stem 43 between the washers `44-45'.and is secured in place by a bolt 41. lThe slot in the block 46 terminates at its :top in a smooth circular curve 48which rests on the stem 43. .and turns thereon. A metal ,strap 4-9 Adepends from the bolt 41 of the block 46. The

pull lrod 2 rests upon that. strap and .may be readily .removed therefrom merely by lifting the pull rod :2 upwardly.

To assemble the `pull rod carrier the link I1 is 4 A slotted oilsoaked hard corresponding hole in the corresponding block 22 of the link I8 until that link abuts against the washer 4I. The lower ends of the links'l1 and I8 are then slipped down upon the arms I2 and I3, respectively, between the washers I4 and I5 so that the slots 21 of the blocks 26 embrace the arms I2 and I3 and with the curved surfaces 28 of the two blocks resting on the arms I2 and I3. The blocks 26 are then secured against upward removal by the bolts 30. The Z-shapel link 35 isv now held against movement in one direction by the washer 46 which engages one side of the ,link I1 and by the corresponding washer 4I which engages the opposite side of the link I8. The

`strap 49 may Vthen be positioned-on the bolt 41. Thereafter the pull rod may be positioned upon that the link lengths be .of certain proportions with respect to onev another. In vdealing with these proportions the lengths or distances considered are the center to center distances between the respective pivots.

The proportion vof the linkage is such that the path of movement of the center 50 ofthe stem 43 is substantially a straight line Within-the iii-nits i of motion ofthe pull rod 2. A suitable linkage for obtaining this result with a pull rod having astroke of 42 `inchesis of the following proportions:` `distance between the centers of the arms I2-I3,'34 inches; lengths of links I1-I8 from center to center of the arms I2-36 and I3-31, 13 inches; center to center distance `of the arms 36-31, 22 inches; center to center distance be tween the stem 43 and the center of the Z-.shaped link 35, 30 inches.

Itis to be noted that the axis of the pull rod 2, as seen in Figure 3, is vertically centeredwith respect to the links I1-I8 and the Z-shaped link 35. This 4eliminates uneven [stresses on 'the bearings tending to twist the links.

As the pull rod moves to the right ofthe posi tion illustrated in Figure 2 i't draws the pull rod carrier with it from the full line position to an extreme position illustrated by the dash lines of Figure 2.V At that extreme position the arm 36 abuts against the supporting rodv 9 and limits the l extent of motion yof the carrier. Any additional movement of the pull rod 2 to the rightfafter the carrier reaches its limiting position, results merely in slipping or sliding of the pull rod on the lsupport 49. When the pull rod commences yto move in the kopposite direction it draws the carrier with it from the `das'hposition illustrated,

.to its center full line position and onward to a position approximately corresponding to the `dash position illustrated but on the opposite side of the center. The-*carrier is proportioned so that the length of the stroke `of the center point 'm .opposite directions, as limited by abutment -of the arm .36` or the arm' 31 against the rod '3,

is slightly inexcess of the maximum stroke of the.. .pull rod 2. Therefore, if the pull rod is re.- moved from the carrier while the carrieris in anyv position, and replaced onthe. carrier after thek carrier has moved to another position, then rageesgssz during the first stroke of" the pull rod it willdraw the carrier to one extreme position or thelother` thereof andthen `slidelonthe carrier` until the pull rod is againtcenteredonthe carrier. `'I'hereafter, during operation ofwthe pull rod there will be nofurther `slidingof the pull rodin the strap 49. l l y is anlequal distance from the pivots andis adapted l to reciprocate in a substantially straight line mof tWhen the carrier is infits mid position the entire weight of the "pull, rod is carried `by the links` ,l 4I 1`I 8 both of which are in compression.- This continues 4even until the carrier reaches its limitl ing position for evenin itsextreme position, i1- ilustrated in dash'lnes of FigureZ, `thelink, I8 is l still on the same side of4 a verti-calplane passingA throughy lthe pivot axis J3. The `link i8 `never "passes through a Vertical' position. There-fore, "even: in its extreme position theforce on the link` `l'l due to the weightofthe pull :rod is still in -beA ,the` case if the link wereplaced inalternate compression `and tension as `the carrierjmoves :pull rod carrier moves rfmmloneextreme position "to the other. Fromthe above it is `apparent that the proportioning of thelinksof the straight line Voperating mechanism is so correlated to the length of the fstroke ofthe pull rod that the `stopping prisingga `base member; inclined convergingarms l .tion, said' cross member abutting against thebase `asthe cross memberypivotsga fixed distance in reither direction from fits `mdposition to stop the reciprocating-motion of said. supportat xed `2.1Apparatus ofthe character describedfcom-` l .pivotal'ly supported at one end in spacedrelation ;.said .base member, a member `pivoftally supportedgbetween the opposite endsof the arms, a

support afliXed to said pivotally `supported mem` `ber andlocated `an equal distance from both plvotal `supports i of the pivotally supported member `and at a` distance from the said pivots of the last compression l As aresult `the bearingblocks 22 .and `Ziwearonlyat one surface, which would` not :1H

l through `its cycle. This permitsya simple` construction` ofy the `blocks '25,@` Furthermorelnsince the `blocksfare always ingcornpression any Iwear on the `bearings will not result inback` lash as the actionbf the carrier is obtained before either arm` Mlil` or I8 passes through its vertical position. l Wear `on the bearings 22-26merely resultsin a slight `foreshortenine:; of the effective lengths `of the links Il-l8'. This is of such small magnitude as to produce a `negligible effect inthe straight line `travel of the` center 513. Thisis possible `because the links IT-I8 are always ,in compression .dur-

`ing the movement of thecarrier fromone eX- treme `position to theyotlfierzA `li the links were in berat'iixed points;

ping the-motion of said member greaterthan` the distance `,between those pivots, land vadapted to reciprocate `in a substan- ,tially straight line, `arid substantiallybelow the I "basemember, 'the distancesybetween the pivots being such that the directionof` swinging movement of either arm is reversed as it approaches a vertical position and before it pivots through its vertical: position, andmeans `for positively stopf pivotally supported mem- 3; A pull rod carrier comprising `a base, `a cross `member pivotally supported at each end by arm u i lmembers of equal length which are pivotally attached to said base, said cross member having a part `which is rigidly iixed to the rest ofthe cross `member and depends` to ailevel substantially bey low the base, apull rod support pivoted at a lower `pointofsaid part which point is an equal distance from `both pivots and isadapted to reciprocate in a substantially Astraight linemotion, at

\ least @neuf said membersabutting against the tension during pari-cfg the stroke thenlwear `on theybearings` could not be` tolerated for, under such circumstances 4thecarrier would` knock dur- B y providing a` While I have shown A.the pull rod supported i `from the block V,dliuby means ofthe strap 49, this 1s i not an indispensablepart of` theqinvention.'` For instance, the pullrod mayrest on` thetop of Vthe block 46, ii?` desired;` Under such circumstances rthe toplof the blockwould be provided with a yshapedgroove `for receiving the pull rod andhold-` inglitagainst side movement across, the b1ockin the manner illustrated in my pendingfapplica` Ition, Serial No. 272,8651` i `In `,compliance with the requirements of `thez `patent statutes I have hereshown and described f `apreferred embodiment of myinvention. ,It,is,`

however, ,to be understood `that the invention, is l not limited to the precise constructionhere shown,

the Samebeing merely illustrative of` the prin` i, rciples of th,einvention` What I consider new and: l fdsire to secure by. Letters Patent is:

, "1. A pull rod carrier comprising a base, a cross` member pivotally supported at each end by armsI -of equal iengthvwhieh are pivotauy attaclmedto,Y said base, said cross member having a part which is rigidlyxed to the rest of the cross member and depends from a line joiningthe pivots atthe" port at a xed point.

base to Ystop the reciprocating motion of said supl :41 Apparatus ofthe characterdescribed com-` i prisinga base member, arms pivotallylsupported at one end in spaced Vrelation `by said base mem- 1l ber, a, cross member pivotally supported between theopposite ends `of` the arms, a support alxed to said cross member and located an equal disf tance from both pivotal supports of the cross member `and at a distance fromthe said pivots `of the last member greater than the distance between those pivots, and `adapted* to reciprocate in "a substantially straight-line` said `cross. member moving into abutment with" the base at a point adjacent the pivot between thecross member and at least one of thearms for positively stopping themotion of said support at xed points. 5;,Apparatus of the character vdescribed comprising a base member, upstanding armspivotally supportedin spaced relation bysaid base member, a depending member\;pivotal1y supported intermediate the upper endsof said `arms and depending below thebasemember, a support affixed to said depending member below the base member adapted to reciprocate-in. a substantially straight line, a `portionof the depending member that is adjacent the pivot between it `and each arm abut- ,-tinggthe base memberas the arms pivot, for posi` xed points.

tively stopping-,themotion ofsaid support at 6s In combination with a horizontal `longitudilnally reciprocating pull rod, vapull` rod carrier supporting the rod and comprising a straight line l `operating mechanismpivoted about two spaced `parallel horizontal axes abovethe pull rod and at right ang-les theretoiand adistance apartless than l i '3 ends of the` cross member, a pullrod support piv"` noted at a lower pointof said depending part which the stroke of the ro'd, and a pull rod support pivoted .on the carrierat a straight line vmotion point thereof below said parallel axes, said pull rod resting :on said-support, f

7'. Aistraight VVline operating mechanism comprising a support, a pairy of equal arms pivoted on the support and extending upwardly therefrom, a link pivotally'connecting the upper ends of the arms and having a depending portion extending below the support and having a lpoint thereofv below the support movable in a straight line, said linkv being movable into a position in abutment with the support as Vthe straight line mechanism operates, thereby limiting the stroke of the mechanism.

l 8.-'A straight line operating mechanism lcomprising a support, la pair of equal length upstanding arms pivoted on said suppo-rt, and a Z-'shaped cross member pivotally connecting and supported by 'the arms, said'cross member overlying the support and being moved into abutment with the support as the arms pivot in either direction from va, mid position, to limit the movement of "thee mechanism in each direction from the lmid position.

l 9.v A straight line operating mechanism Icomprising a' support having spaced parallel horizontal stationary pivot rods, a pair of arms of equallengths each of which has a bearing block at its 'lower end, the bearing blocks being slottedv with the'slotted portion of each block embracing a rod and resting thereon whereby the arms are pivoted on the rods, a cross member pivotally con- 4nect'ing the upper ends of the arms and having a vvdepending portion a point of `which is located an equal distance from the lpivotal connections bejtween the arms and the cross member.v

`ing the extent of insertion ofthe arms into the bearing blocks, means pivotally supporting the opposite yends of the links, and means at said opposite ends for restraining the links from movement in a direction longitudinally of said arms. ll. A linkage comprising a Z-shaped cross member having parallel arms joined by a diagonal member, a pair of equallinks having Ybearing blocks at one end, the arms of the cross member extending each through one of the bearing blocks, stop means on leach ofthe arms between the di1 ll-11n combination with a horizonta-llongitudinally :reciprocating pull rod, a pull rod'carrier .supporting the rod vand comprising a straight line operating mechanism havinga pair of equal arms `pivoted about spaced stationary axes, :a `cross vmember pivotally joining the arms 'to swing `about two movable axes, a pull rod support carried rby the cross member at a point which is an equal distance from the two movable axes, the length of an arm plus the distance between the movable axes being less than; the hypotenuse of a lright triangle of which one arm and the distance between the stationary axes constitute the othertwo sides, whereby the direction of swingofeither arm is reversed as the arm approaches a vertical position and before it pivots through avertical position, the distance between the fixed axes being" less than the stroke of the rod.

13. A straight line mechanism comprising a four 'link chain pivoted together to constitute a quadrilateral, said chain including two opposite links of equal effective lengths and two ofv un'- equal lengths, the smaller of the two unequallin'ks overlying the'other of the two lunequallinks and being moved into 'abutment therewith asl` the equal links pivot in either direction from a mid position, to limit the actuation of the mechanism in each direction from the mid position. y 14. A' carrier comprising a four link chain pivoted together to constitute a quadrilateral', two of the links being of equal effective lengths and the other ltwo of `unequal lengths, supporting means comprising a pivot and means maintaining said pivot spaced a fixed distance from one of said unequal links and spaced substantially equidistant from the two pivots of said one of the junequal links, the longer of said two Vlast mentioned links also constituting a supporting means; a support for the carrier at one of said supporting means, the, other supporting means including means for supporting a horizontally reciprocating rod, the reciprocation lof the rod actuating the agonal member and the bearing block for limiting the extent of insertion of the arms into the bearing blocks, the `bearing blocks being slidable along the arms in a direction away from the diagonal -mem`ber and the stop means, means pivotally shanks embraced by the slotted portionof` said slotted blocksand supporting said blocks.

linkage in a to and fro motion, a part of one of the links of the chain being moved into abutment with a part of another link of the chain at points slightly beyond the limitsof the stroke of the rod to limit the actuation of the carrier.

15. A pull rod carrier for a reciprocating subf stantially horizontal pull rod of such length vas-to a pair of equal links, means holding the ends of the links a xed distance apart and providing parallel pivot axes a xed distance apart, a cross f member pivotally joining the links, another pivot axis, means/including the cross member for maintaining the pivots between the cross member and the links at xed equal distances from said other pivot axis, said other pivot axis and the i-lrst mentioned pivot axes being relatively movable with respect to one yanother in a straight line under the guidance ofthe cross member and the said links, said cross member overlying and being moved into abutment with a part of the carrier as the links pivot in either direction from a mid position, to limit the actuation of the carrier in each direction from the mid position. Y,

ALLEN M. ROSSMAN; f

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