US1600783A - Underreamer - Google Patents

Description

Sgt-21 1 25. 1,600,783

w. E. YOULE UNDERREAMER.

' Filed Oct. 2, 1922. 4 Sheets-Sheet 1 IN VEN TOR.

g mlzizmlfyauifi Patented Sept. 21,1926.-

-' i V I 1,6tt,783

WILLIAM YOUl'i E, 0F LOSANGELES, CALIFORNIA.

UNDERREAMER.

Application filed October 2,

This inventionrelates to underreamers for reaming well-holes below the well casout overloading any one part of the tool.

One of the major objects of this invention resides in the provision of anew type of underreamer characterized by having one reaming cutter or bit slidable inthe body relative to the opposed cutter and in 'an arcuate path, the-opposed cutter being approximately stationary as to longitudinal translation .and supported to tilt in av collapsing operation under control of the slid-V ing cutter.

Another object is to provide for a quick immediate release of the cutters when stuck in the well bore, such release being accomplished without disengagement of the dovetails of the cutter shanks from full contact against the outthrust surfaces of the companion dove-tail ways in the body, such full contact maintaining during the whip of the tool in a reaming operation.

Another object is to provide an underreamer .in which all possibility of losing the cutters in the well-bore-is eliminated, the parts being so proportioned and ar ranged that in case the supporting means of either cutter be broken the other cutter will hold the broken cutter against loss from the body.-

A further objectis to provide an underreamerhaving one-tilting and one sliding cutter each provided with dove-tailshanks engaging'companion dove-tail ways ill the body, and in which neither cutter shank has apivotal action on outthrust surfaces of the ways. r

Another object resides in the provision of a spring actuated rod for supporting the sliding cutter, with intermediate connections betweenthe rod and cutter compensating for the arcuate movement of said cutter.

, i another object is to provide a spring and position.

1922. Serial N0. 591,745.

rodcontainer removable laterally from the body as a self-contained unit, and inwhich the spring may be maintainedunder tension during removal-of said unit.

A further object resides in providing an underrea m'er in which in-thrusts are trans mitted directly from onecu-ttcr to the other bearingsurfaces are arranged to relieve the cutter shanks and dove-tails of excessive strains. i

ing and arrangement of parts by. which it below the body, and inwhich the up-thrust i is possible to provide largedovetails'well ii set into the body, cutter shanks of exceptionally large cross-sectional area, exceptionally large and direct up thrust bearingsurfaces,-'a non-removable support forthe tilting cutter which will not prevent a removal of said cutter, cooperation between the two cutters which will positively insure their expansion, exclusion of such dirtor foreign matter aswould interfere with free i functioning of the parts and cause excessive wear, and to provide a one piece body. in

which all the recessesare exposed and easilycleaned when the cutters are removed;

A further object. resides in' the manner ofremoving the cuttersby a manipulation which bore. V

Various other objects and advantages will could not possibly occur in a wellbe more fully apparent from the following description of the accompanying drawings which form a part of th s disclosure, and

which illustrate a preferred form? ofenibodiment of the invention.

Of the drawings:

Figure 1 is an elevation-of my improved underreamer, the cutters being in expanded position.

. Fig, 2 is a similar elevation of the lower portion ofthe underreamer, the cutters being in collapsed position. Fig. 3 is an enlarged bottom I lan view of Fig. 1. I

F ig.: 4 isan enlarged bottom plan viewof Fig. 2.

Fig. 5 is a central vertical section showing the cutters in collapsed position.

Fig. 6 is a vertical sectionon line 66 of Fig. 10, showing the cutters in expanded Fig. 7 is ,a section similar to 6, sl1ow- 65 'Another object resides in" the proportiontion of the underreamer looking at the left;,

ing the cutters in partially collapsed or in release position.

Fig. 8 isfla detailelevation illustrating the .manner of removing the spring container spring rod from the lips 22 which engage behind angled abutrnent surfaces 23 on the body to hold the ,lower-endof the spring carrier in place and for disconnection of the sliding cutter.

Fig. 9 IS an elevation of the lower posihand side of Fig. 1.

F 10 is an elevation looking at the right-hand side ofFig. l.

13-13 otFieg 6.

[ Fig.5 11 is -a central yerticalsection of, lower; 1 portion of thelbpdy, F g-1 12 s n. enla ge b Qm P lNieW of the body.

'F'igg13 is an the n arged ,section 01 line 7 Figqlit is; an @marged flsgctibng Oh line .4=.,O,Fig..5;

Fin". 16" is an enlargedeperspective view.

C u I" I r of the iltmgteatter, ands-.1 a HFig. 117 is a enlarged perspective view of the sl idingfclltterq In th ad wln 's '1 n 5 I a 7 I A or the .underreamernhav ngthe :usual tapered pin 2, forattachment to the tool string, and provided-at itslower end ,with opposed. I openslipwaysg andlttzoereceivethe shanks r of the cutter-s. Thesside-cwallsof the respec; v tive slipflwaysiare groovedtongproviderdove tail waysfijandfi,the'guideways.oidefiningt tention is directed to the several views, and; ,t

outthrust hearing;surfaces] which, are londiate webte9 providesian abutment or; seat which supports the tilting, cutter and the ripper, wall ll' 'of thersli-pzway 3 provides an f inwardly and upwardly angled tip-thrust surface; which will belengagecl by the upper end of-the shank of; the tiltingv cutter as Willi later .be HeXplained The vlower vend ofthe body-1 provides transverse up-t'hrust hearing faces .or surfaceslQ. and 13 :on each USlClQ of the respective slip-ways these up-thrustsurfaces being preferably anglednor inclined inwardly and upwardly towards each other." h se 521965512- andul3e preferably -c0nsti.-' tute the extreme lower end faces of the body.

The side Walls of thebodyabovethe slip way 5t is longitudinally .groovedfltol provide a. spring chamber 1 5 \vhich;.cornmunicates Qwithv said slip-way,-:,the side wallsofsaid chance her being in plane with the base of the dove tail ways, 6 so as toattordxaneasy machining of said ways and said chamber.

The-spring charnherv15 is adapted: to :recelve a self-contained.springrod unitcoinprising a cover plate oruspring container 16 having. an inwardly. extending lateral. lug

pro'vided'with a vertical bore 18 through; V '19, and piyotallyiconnected-ttheretojoy aa'pin which spring rod: 19 extends and a spring the groove125 when; the plate {is in. placeo j.

vertical sectionhon, line designates, the body. I

.sertedi a suitable tool to pry the pl ateiloose.

, fore does 7 not requirel -any. screw-threaded;

lshank fil, the upper end of whicha-isaiangled. to the same, degree-as s the ,upper -.wall1.

sinwardly extending pintle:nose: .or :pivot engagement upon the abutment- 01 seat- 1t) an upwardly extending shank 37 having its;

the free end of the lateral lug 17, engages. into a recess 2a in the body, so that thee75 strains occasioned by the tension of the spring will. he transmitted: directly; to tllBz M body. The upper Wallofthe chamber 115, is.

angled inwardlyand downwardly; anclhas'a f centraLgroove-25, anclthe., upper.lend ofv'ethe $5M platelllfi is correspondingly angledqandusv provided with a lug 26 adapted to ineshiinto The plate :16 is isecuredin placesby aJbQlUQ-Z. which extends laterally through aligned 'ap ertures in the body and win the lug .26; with v the bolt; retained in place by. a splitv cotter;

pin 28, (see Fig.-10).- To facilitatelatre inoval of the cplatera't'ter the boltthastheeni. retracted, arecess'29 is providedatithe up- .20; per end ofv the lug 26 intowhiclrmayabe in:-

a The above described or anization of.) art t a b l provides/a one .plecebody havlng nocentlail i ly bored spring 'chambe rnandswhich there,

jointsor sub-connections. 3 7

Describing thereamingeuttersiorcblts aa :particularly to Figs. 16 and 17. Thentilt- 2 9) ing cutter-30 has an upwar.dly-. extendin ofthe slip-sway .3, and isvprovidedvwith an projection "32 which has a ..slidingpivotalt on' the web 9 ofr the loody fOn opposite sides of theshanlr3l, the body-loft the cut-. l ter 30' extends laterally to form-,up-thrtist bearing surfat'es 33 angled for icooper-a' tive engagement with the transverse tip-thrust bearing surfaces 12 of the body-. when'Tthe cutters are in expandedposition. v- Dove-tail. i

ribs 34 extend outwardly'fromthe side w-allsv- .oif the shank SL-andwheiwthe cutterwis' in "position in the slip-way 3, these dove-tails; sl dably :engageain the dovevtail ways 5,,

their outer edges -35v providing outthrustpw bearingsurfaces for engagement.withithe :29

. 'out-thrust .hearingisurfaces 'Z-formed-by said m .ways. a

The :sliding reaming cutterror :bit- 3 6;ha's g 1.

upperrendibifurcatedto lGCQlVQuiJllB lower.x

end of a link .38to :which it is pivotally .con-

l nected by a'pin 39., the upper endiofcsaidr1m :link extendingbetweenthe arms of aiforkedv 1 'head 40 on the lower end of the spring rod 41. On opposite sides of the shank 37, the body of tlie'cutter 36 extends laterally'to form up-thrust bearing surfaces 42 angled these dove-tails slidably engage in the. dove tail ways 6, their outer edges 44 providing arcuate' out-thrust bearing surfaces which are longitudinally curved correspondingly to the arcuate out-thrustbearing surfaces 8 formed bythe companion dove-tail ways 6;

The opposed transverse surfaces'of the bodies of the two cutters are formed to iii-.

' termesh when the cutters are in collapsed position, as shown in Fig. 5. l/Vhen the cutters are in such collapsed position a latch shoulder 45 onthe cutter 36 engages beneath a companion latch shoulder 46 onthe cutter 30, and as these shoulders are approximately horizontal when the cutters are collapsed, the cutters will remain collapsed until the reamer is jarred, whereupon the tilting cutter 30 willswing away from the sliding cutter 36 under the influence of gravity and permit an upward movement of the sliding cutter under the influence of the spring to expand the cutters. 7

Upon such release of the cutters and during the upward travel of the sliding cutter, the corner 47 of the cutter 36 will ride upwardly on the transverse expanding surface 48 of the cutter 30 to initially expand the cutters, and then the surface or'abutment shoulder 49 of the cutter 36 will engage the surface or abutment'shoulder 50 of the cutter 30"and complete the expanding 0f the cutters.

The surface 49 is of the same curvature as are the arcuate dove-tails 43 and-the surface 50 of the cutter 30 is correspondingly curved so that during any downward movement of the sliding cutter 36 from its expanded po-' sition and while the surfaces 49 and 50 are in engagement, the dove-tails of both out ters will remain in engagement with the outthrust bearing surfaces 7 and 8 of the ref said cutter together with the arcuate surspective dove-tail ways. a 7

When the cutters are in expanded posi-. tion, as shown in Fig. 6, the surfaces 49 and 50 further serve as in-thrust bearing surfaces, their cooperative engagement transniitti'ng in-thrusts directly from one cutter to the other below the body, thereby reliev ing the cutter shanks and their dove-tails of a large portion of the strains caused by such iii-thrusts, which are usually due to glancing blows-of the cutters against the walls of the well bore. In instances where the cutters become stuck in a well bore it becomes necessary to partly collapse the cutters soas to release the cutters. 'This is accomplished by pulli ing upwardly on the body of the underrsamer, causing a longitudinal sliding movement of the arcuate surfaces 49'and 5O relative to each other andan initial collapsing of the two cutters. ture of the arcuate dove-tails 43 of the sliding cutter this initial collapsing or release of the cutters is accomplished withoutwithdrawing the dove-tailsof the respective cutters away from their full contact'with the out-thrust bearingsurfacesof the dove-tail ways, therefore, I provide for a quick release of the cutters-without any slapping 0f the dove-tails in their respective Ways. This is an important consideration as in many types of uiiderreamers such slapping:

lease of the cutters and during the whip of the drill cable, constitutes one of the ma-' ]or causes for crystallization of the cutter shanks and the ripping out of the dove-tailsfrom the body. 1

tsit is desirable to provide a positive tilt ing of the cutter 30 to collapsed position, the

upper 'end of the sliding cutter shank provided with a cam shoulder 51 which dur'-- 5 7 ing thedownward movement of the'sliding cutter, is adapted to engage the end of the 1 nose 32 ofthe tilting cutter, (see. Fig. v7)

and positively swing said cutter to the collapsed position shown in. 5.

The underreamer of the resent invention is also constructed so as toprevent loss of the cutters in the well bore and contribut- By reason of the curva- 'of the cutters in their slipways during a rev I ing to this object, the cuttersare provided with shoulders 52 and 53 which may be considered abutment shoulders; they are adapted to interlock when the cutters are in collapsed position. p In considering'the possibility. of breakage of parts, it will be quite evident that the Y cross-sectionalarea ,ofxthe supporting nose; 32 ofthe tilting cutter is of such dimensions that breakage thereofis a remote possibility.

However, if this nose 32 should become brokenoff, the cutter 30 will not drop from 1:

the body" when in expanded position, by

reason of the fact that the longitudinally angled dove-tails and dove-tail ways of faces 49-50 form, in eifect,a wedge preventing a dropping of the cutter v3O so long as'even a relatively short portion of the dove-tails 34 remain in the companion ways 5, and. when the cutters are in collapsed position the. engagement of the latch shoulder 46 on the latch shoulder 45 will hold the cutter 30 from dropping. It is therefore. evident that even though a major portion ofthe shank .31 should be broken off, the

provision of a self contained spring rod unit removable laterally, permits a one piece body in which the sp 'ing chamber is aligned with one of the open slipways and can be easily machined, j a H In a four and one-half .inch underreamer the arcuate dovetails permit a transverse release of three-eighths of an inch witha down pull of only three quarters of an inch. 7 This small movement of the sliding cutter during reaming means less wear, less shock, less crystallization and less strain on the bolt and spring. e Furthermore this movement is'so slight that nothing large enough to do damage can get between the up-thrust bearing surfaces. At all times during reaming, thesliding cutter ofa four. and one-half inch underreamer has a fullbearing over four inches in length on its dove-tails. V I

The tilting cutter is held inthe body by its heavy lug or, nose which engages the web between the slip-ways. The lug extends across the entire face of the cutter shank and locks into the body without the use of keys or pins. Even should the lugshear, this cutter cannot drop from the body as long as the other cutter is present. The cooperat ing arcuate inthrust bearingsurfaces of the cutters extend the full width of the-cutters and insure an even action against a glancing blow on either cutter.

The collapsing action of the cutters is made positive by the camshoulder on the sliding cutter engaging the supporting nose of the tilting cutter, and this positive action also insures the cooperation of the two safety interlocking shoulders on thecutters.

I From an inspection of the drawings, the. simplicity and strength of the body'con struction will be apparent, a continuous slot serving for both the sliding cutter and'the' spring, and the side walls of the spring chamber are solidly braced against crushing, by the spring container." i /ith theoperat ing partsremoved all the slipways and resated for by building up this arcuate bearing surface.

cesses in the body are exposed and areeasily cleanable. This method of mounting the. springand spring rod-makes possible the elimination of adrilled spring chamber in the body, and obviates the necessity ofa jointed body. The body and cutters-have-been so designed as to reduce wear to a ininimumand the movement of the sliding cutter in reaming is so small that its wearing effect will be negligible. The tilting cutter, which in reamingdoes not move in the body, can wear at only one point, the broad arcuate inthrust bearing surface below the body. lVca-r at this point can easily be. compen- Furthermore as the 'arcuate surfaces and dovetails wear evenly,-'these may be bu lt uniform curvature bowed up, and refinished to take up. for wear, without any work on the body.

While the specific form. of construction herein illustrated and described providesa tool fully capable of fulfilling all of the ob- .jects primarily stated, it is to be understood that I donot wish to limit the invention to the one formof embodiment disclosed,'for

having a longitudinallydisposed arcuate slipway uniformly curved upwardly and outwardly from thesaid upthrust bearing surface, the uniform curvature enabling the same to guidea cutter to slide inan are.

-23. An unde'rreamer' body having an up- ;thrust bearing surface constituting the extreme lower end face of the body and having a. dovetailed guideway capable of guiding a cutter to slide in anarc longitudinally disposed in the body and extending up wardly from the said up-thrust bearing surface and having arcuateout-thrust bearing surfaces uniformly curved upwardly and outwardly. I

l. An underreamer body having an upthrust' bearing surface constituting the extreme lower end face of the body and having a dovetail guideway for, guiding a cutter to slide in an arc longitudinally disposed and extending upwardly from said upthrust. bearing surface,: said gu deway' hav ing: arcuate out-thrust bearing surfaces of middle portions.

outwardlylat their 5. An underreamer; body having I anl upthrust bearing surface; constituting the ex-:

treme lower end faceof the body and having :two opposed longitudinally 1 disposed guideways extending upwardly from said I bearing surface, one of said guidewayshaving straight out-thrust bearing surfaces and the other having arcuate out thrust bearing surfaces of uniform curvature capable of guidinga cutter to slide in an'arc. f

6, An under'reamer body having an upthrust bearin surface on its lower end, and

two opposed longitudinally disposed open slip-ways extending upwardly from its lower surface, .and an intermediate web havmg means to cooperate with one of the cutters to supportthesame, one-slip-way defining straight out-thrust bearing surfaces and the other defining uniformly curved nrcuate body having arouate-g guideways receiving e with faces clonstituting out-thrust bearing -out thru'st bearing.surfaces,*and constitut move;thersame up and-dovvn in the-'underj ing a guidewa'y for guiding a- -eutter to reamer body.

lide inan' arc. r 12. In an uniderreamer, the comb nation 7:'An u-nderream'e'r bodyhaving an upof anhnderreanier body, a cutter having a '5 thrust-bearingsurface on its lower end, and body-portion. provided With a1cuate e2; tvvo opposed ;longitudinally disposed open paneling surface on its'i-nner face and pro- "slip-Ways --extending' --upwardly from its vided With a shank having means for sup; 7 lower surface,- oneslip-Way defining straight -porting-the cutter extending upwardly trom out-thrustbearing surfaces"longitudinally said body portion'and having longitudinally angled upwardly and outwardly and the disposed,- arcuate, dovetail ribsextendmg other slip-Way defining longitudinally dis'- from itsyside' faces, said-underreamer body posed arcuate 0utthrust bearin-gsurfaces of having' -arcuate guidevvaysreceiving the unifornr-curvature;constitutinga guidevvay dovetail ribs, and means co'operating'with ffor guiding-a 'cntter to slide in an arc. '---.-the'eutterto movethesame up or-down in 5 8. In an underreanier', thecombination of theguideways. V v

body *havingagroove in itsside -Wall eX- 1"; 13. Inanunde'rreamer; the combination --tending-upWardly1 from its lower-* Surface, of an underreamerbody, a-cutter having a the lower portion ofsaid-groove-torming an; body-' iportiomprovided 'With. latching openaslip wvay and-"th 9," upperportiont-here o'faiforming-ga sprin g' chanaberya spring loshoulder and with anarcuate expanding I surface on its inner side, said cutterhaving cated in thespring-:eham-ber, theWvalls of the] lower -portionot-the groovevybeingdovetail shank extending upwardly from the body-portion, andhaving an abutment formed to provide arcuate,outrthrust-bear --shoulder onthebodyportion, and a comi g rfa cut gui-ded iIi p y-mpanion cut-ter'having an. abutment sl'ioulder 'and==cooperatingwith the spring, and a re}, movable cover for the spring chamber. 9. An underrea-mer body having tWo op and toi.;eng age the first named abutment P P fi P y extending np ard y "shoulder and cooperatekwith the same to v from itsve xtreme 'lower en'd fa-cewith said hold the cutters in an expanded relation.

face on opposite sides ofthe slip ways pro- 14; 1 An d am having a 'body, a vidingi opposite up-thrust-bjearingsurfaces-reamingcutter'tiltingly' supported in the angled-upwardly ancl inward y towards'each lower end of the body, and alongitudinally 'f-Ot e one' 'slip-zwa y having its-.top Wall' movable-reaming outter'mounted and posi- =ang1ed r y p ar y S tivel'y guided in'thebody in an arcuate'pz'ith, p WELllS 1' undercut t0 PIOVlClG 'WSJYS the tworcuttrs a ooperative ut-fey defining out-thrust bearing surf-aces; and expan'ding--engagefnent v h ip y e g d rc p vi I 15. An"uIiderreamer "having a body, a e -'1 W g 511961121118 Out-thrust. spring flCttlttQd'fIOflSlldiLbl in the "body, a bearing surfaces of uniform curvature, 'oonl i it di' fl mgvablg reaming, utter 40 ""Stitutingguidewayslto guide Wcutter inim; 'IlGCtBClWltll said rod andmounted and posi- O- p 7 tively guided in the body in an arcuate' path, In an l rr fl ma and a second. reaming cutter tiltinglv supi of a body,- a cutter liaving abody-portion and 'a shank extending upwardly therefrom- 5 having means for supporting thecutter, "said shank provided with longitudinally' dis posed, areuate dovetail ribs" extending froirr its-oppositeside Walls, the-said underreamer rod and'oooperating with the slidable cutter in acutter expanding operation,

16; An .underreamer. having a a j body, a spring actuated rod slidabl'e in'the body, a longitudinally movable reaming cutter cennectedwith saidrod'and slidable in the body in an arcuate path, and asecond reaming cutter tiltingly supported in the body independently of said rod, said cu ters ha: A ing-inner' surfaces cooperating to, cause the the -dovetail-ribs' and guidingthe ;cutter, T i and-means'for controlling the cutter'to-Tnove -thejs'ame up or jdown in-thefgnideways. I

L a 11 In an 'unde-rreamer,"thesc'ombination k of; an un'derreamer-body, 'a cutter having a body-portionflend ashank extending up;

ardl therefrom having means 7 for sup porting the cuttergsaid shank having up j' e'af g.urfaceson eitherside of the, the'sliding cutter, effects a positive'collnpsishanl'rysaid shank-also'having do vetailed'ribs. ing movement of the tilting cutter.

i 17. An underreamer having a body, a longitudinally immovable cutter pivoted in the'body totilt transversely, a second cutter to permit said cutters t0v collapse when in another pos tion, and other cooperating surfaces, the bodyo'f the cutter below the shank having an arcuate expanding surface on its nner face, said; underreamer body. having matic mean'si adapted to 'tr'ansiate said to cooperate -:With the latching shoulder i when the cutters are in a collapsed posit-ion,

'cutters to expand When in oneposition, and

"faces whereby a collapsing movement of ported in the body independently of said i p V V longitudinally slidable in the'body and posiarcuate guide ivays for receiving said r1bs,-t1vely guided'in an arcuate path, 'andautoefifand means cooperating with the cutter to 33$ 0nd cutter, said cutters being free-ofeach. other and normally held expanded by said' means operating the second cutter.

18.' An underreamer having a body, a cutter pivoted in the body to tilt transversely, a second cutter longitudinally slidable in the body and positively guided in an arcuate path, and automatic means con- 'nected to said second cutter and functioning to elevate said second cutter, the cutters being free of each other and expanding upon the upward movement ofsaid second cutter. V

19. An underreamer having abody, a

longitudinally immovable cutter pivot-ally supportedon the body totilt transversely, and a second cutter free from the first cutter and spring-actuatedly mounted in the body to move longitudinally with respect to said body and first cutter and positively guided in an arcuate path, said cuttersexpanding during an-upward movement of said "second cutter. 4 i v 20. An underreamer having. a body, a longitudinally immovable cutter supported in the body to tilt transversely and project- 1 ing from the lower end thereof, and a second cutter having means for positively cutter longitudinally slidable in the lower end .Of the body in an arcuate path and in respect 'to the first cutter, and means for automatically elevating the second "cutters causing said cutters'to expand, said cutters having cooperating inthrust bearing surfaces abutting against each; other below the body when the cutters are in expanded position.

22. An underreamer having a body pro- I vided withopen slip-ways to receive reaming cutters, a cutter in one slip-way supported tov tilt transversely, a second cutter longi tudinally slidable in the other-slipeway in 3 respect to the first critter and'in an arcuate path, and automatic means for elevating the second cutter to expand both cutters, the cutters having body portions and shank por-.

tions, said body portions with co-operating inthrust'bearing surface extending laterally beyond the shanks. 1

23. An underreamer havinga body, a cutter tiltingly-supported by the body, a second cutter longitudinally slidable in 'the body downwardly with an arcuate path and in respect to the'first'cutter, and means for auto--' matically elevating the second cutter to exabutting against each other when are in expandedposltion. v

pan d thecutters, said cuttershaving cooperating arcuate inthrustbearing surfaces the cutters 24.. An underreamer having a body provided with open slip-ways to receive reamported totilt transversely, a second cutter longitudinally slidable in the otherslip-way in an arcuate path and in respect to the first cutter, and automatic means for elevating the second cutter to expand both cutters, the cutters having cooperating arcuate'im thrust bearing surfaces abutting against each other when'the cutters are in expanded position, and withthe arcuate int-hrust bear- .ing surfaces being of. a curvature.-corre sponding to the arcuate of the second cut-ter. a V r 25. An underreamer having a body, a longitudinally-immovable cutter supported in thebody totilt transversely and projecting below the-lower end of thebody, a second cutter projecting below the lower end of the body and positively guided to slide longitudinally in the body in an arcuate path and in respect to the first cutter, and means for path of movement ,ing cutters, a cutterin one slip-way supautomatically elevating the second cutter to vided with up-thrust bearing surfaces for abuthientgwith thelower end of the' body,

when said cutters are expanded.

26. An 'underreamer havinguav body provided' with open slip-ways 'to receive reaming. cutters and having up-thrust bearing surfaces on opposite sides of the slip-ways, a

' longitudinallyimmovablecutter in one slip Way supported to tilt transversely, a secondcut-ter longitudinally slidablein the other slip.-way with. means for positively guiding the same to move'in an arcuate pathjand expand both cutters, the cutters being promeans for elevating said. second cutter to cause the cutters to expand, said cutters having up-thrust bearing surfaces for contactingsaid up-thrust bearing surfacesof the body when the cutters. are expanded."

27. An underreamer having a body provided with open slip-waysto receive reaming cutters. and having its under surface on opposite side s'of the slip-ways-formedito provide "opposite rip-thrust bearing surfaces angled lnwardly and upwardly, alongitudu nally-immovable cutter in one slip-way supported to tilt transverselyya second cutter longitudinally slidable in the otherslips-way withmeansfor positively guiding the same to move in an arcuate path, and means for elevating said second cutter to cause the cutters .to expand, the cutters havingshanks extending upwardly into theslip-ways and provided with inwardly andupwardly an- 7 gled Lip-thrust bearing surfaces'for cooperat on with'the up-thrust bearl igsurfaces of the body when in expanded position.

" 28. An underreamer having a body pro-"1 able cutter in the'opposed 'slipway, the cut vidingja first slip way defining straight outthrust bearingsurfaces and an-opposedslip-r w'ay defining arcua-te out-thrust bearing surfaces, a longitudinally immovable tilting cutter in the first slip-way,'a longitudinally slid- 'ters-havingout-thrust bearing surfaces for the out-thrust bearing surfaces of :from the lower surface offthe-b'ody and defining out-thrust bearing surfaces aPcutter their respective slipqva'ys arid'inner surfaces- 10, cooperating toexpandthecutters upon an elevation of the slidable cutter, the! upper p'ortions ofsaid inner surfaces having an arcuate curvature corresponding tothat of r the arcuate out-thrust bearing surfaces ofl5 t'he sli'dable cutter, whereb'y'upon an initial downward 'nioveinent or; the sliding cutter an initial collapsing of the cutters is effected while maintaining afullengagement of the cooperating out-thrust bearing surfaces. 29; An underreamer including a'bodyl1avingaside opening spring chamber, a cutter longitudinally sli'dable in the body below "said chamber, "'a' clo'sure for said'cha'mber, a rod'and actuatingspring carrled bysaid clo- -ZS sure," and1neans= connect1ng the" rod with said cutter. p

30." An und'erreamer includinga'body havl'ng a sidebpenmg spring chamber a cutter longitudinally, slidable in the body below -means to permitha removal of the closure,

' l saidchamber,'ai'cl osure for saidv chamber, a

spring actuated rod carried by said-"closure,

a spring eXert-ing an upwardpull"onqthe rod, "means connectlng the rod'with saidcutter, and independent means fo-r' rehe'vmg' saidv connectin'g-Mmeans of the tension of the spr ng for akhsconnectionof SlZLIdCOl'IIIQCtIIIg spring rod'and'springas aunit.

31. An und'erreainer including a body havi in on aosed 0 Jen sli J-wavs to receive ream-' 11 mg cuttersya'nd aninternrediate web, a cutter in one slip-wayand' having a projection? en a in f'said web for tiltin l su aoruin i n t: o b b said "cutter; said 'proj ection' extending into havinga-straight shank extending into the straight slip-way and supported on the body totilt transversely, a second cutter} having an arcuate shank longitudinally slidable in the arcuate slip-way, and automatic liieans V for translating the second cutteigthe inner "Wallsor the cutters havingco-engaglnglatch.

' shoulders and expanding 'surfaces c ausi'nga tail ways and the otherof; said slip-Ways iaving undercut sidewalls defining ar'cuate' dove-tail ways, a cutter having a shank in theo'pposed slip-way g'a second cutter longie I tudinally slidable the-opposed slip-way 'andlmving camslioulder adapted upon "*Yjdow'nward movement of the sliding -cutter,-

to engage the projection Yon the tilting-cutter and positively move it to collapsed position."

An underre'ainer including a: body hava straight slipi-Way and an'opposed' arcur'ate'slip-way, each extending upwardly froin" f the lower surface of the bod a cutter have f ing a straight shank extending" into the" straight slip way andsup-ported on th'ebody to tilt 'transversely a second'cutter' having 'w.-'a1'1*arcuate shank longitudinally sllidable in 5 the 'arcuate slip-way; and automatic means "for translating the second cutter'to' cause anexpanding co-engagement of both cutters.

33. An:- underreamer including a *body having astraightsli" -Way;andan opposed. aremate 'siip wayyeaerest riding "upwardly" the straight slip-way, provided with straight including a body having opposed open -slip-ways extending 'upwardly from its lower surfacejone oi 'said'slip-ways being straight andf' -having undercut side-walls defining straight dovedove-tail "ribs engaging withinthe straight.

dove-tail ways. and supported on the body to tilt transversely, a second cutter having a shank longitudinally shdahle. in said other slip-way and providedwith arcuate dovetail ribsengaging Within the 'arcua'te dovetail Ways, and automatic im'eans'for actuating the second cutter tocau'se an expansion ofboth cutters.

35. An underreamer including "a body having opposed 0 en slip-ways extending upwardlyirom its, ower surface,'said lower surface 'on' op'positesides of theslip-Ways -(:lefining opposed rip-thrust bearing surfaces angled upwardly and inwardly towards each other, one of'jsaid'slip ways havingFundercut SlQlQ-jWfiliS Clefil'llllg Stf'fllght dove-tail Ways angled upwardly and 'out ivrardly and theother of saidslip-ways having undercut side walls defining arc ua'te dove-tail ways, a cutter having a shankin-said one slip-way provided with straight dove-tail ribs engaging, within the straight dove-tail ways and" supported on lthebody to, tilt transversely, acsecond cutter having a shank" longitudinally slidable in said other slipway and provided with arcuate dovetail ribs engaging within the arcuate dove-tail ways,'a nd automatic means foractuating the .llO

second cutter to cause an expansion offboth- Cutters, the cutters having up-thru'st bear ing surfaces engaging'the upthrustbearing surfaces of'the bodyfwheuthe j'cutters are expanded, and cooperating arcuate'inthrust bearing surfaces of a curvature'corre spending to. that of the arcuate'ways' and oirth e slilable cntten- 36. An underreamer body having two opposed longitudinally disposed slip-ways extending upwardly from its lower surface, one slip-way defining straight out-thrust bearing surfaces and the other defining arcuate out-thrust bearing surfaces of uniform curvature, a cutter in one slip-way, and a cutter in the other slip-way, said cut ters having faces which abut against each other and co-operate to hold the cutters expanded.

37. An underreamer body having two opposed longitudinally disposed open slipways extending upwardly from; its lower surface and an intermediate cutter-supporting web, one slip-way defining straight outthrust bearing surfaces and the other defining uniformly curved arcuate out-thrust bearing surfaces, a cutter guided to slide on the said arcuate bearing surfaces and a cutter co-operating with the same and mounted in the other slipway.

38. In an underreamer the combination of a body, a cutter'mounted on one side of said body with means for holding the same against longitudinal movement in the body, a second cutter mounted on the other side of said body, said second cutter having means for positively guiding the same in an arc extending downwardly in the body and operating to permit the second cutter to move downwardly with respect to the other cutter and inwardly toward the axis of the body, while the first named cutter is maintained against longitudinal movement in the body.

39. In an underreamer the combination of a body having a straight dove-tailed slipway providing out-thrust bearing surfaces, and having an arcuate dove-tailed slip-way on its opposite side providing out-thrust bearing surfaces, a cutter in each of said slipways and co-operating soas to have.

transverse collapsible movement, and capable of an expanding movement with both said cutters in engagement with their outthrust bearing surfaces.

40. An underreamer including a body having a side opening spring chamber a cutter longitudinally slidable in the body below said chamber, a closure for said chamber, a spring actuated rod carried by said closure, and means including a pivot connection connecting the rod with said outter.

Signed at LOs Angeles, California, this 23d day of September 1922.

WILLIAM E. YOULE

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