US1485642A - Expanding rotary reamer - Google Patents

Description

'Mwah 4 F. STONE EXPANDING R OTARY BEAMER Filed April 1l, 1922 5 Sheets-Sheet 1 l mvENToR A 25 Freder/c/r 370 ne.

ATTORNEY March 4 E924.

` F. STONE EXPANDING ROTARY REAMER Filed April 1l, 1922 3 Sheets-Sheet 2 ATTORNEY March 4 F. STONE EXPANDING ROTARY REAMER Filed April 11. 1922 3 shetssheet :a

2 5 k IVN Patented Man, 1924.

iaeaaaa NETE@ TAFS PATENT @FFHCCQ FREDMICK STONE, 0F SPOKANE, WASHINGTON, ASSIGNOR T0 DIMOND DRILL CON- TRCTING COIVIPANY, 0F SPOKNE, WASHINGTON'.

EXPANDIN G ROTARY BEAMER.

Application led April 11, 1922. Serial No. 551,549.

To all whom it may concern.'

Be it known that I, FREDERICK STONE, a citizen of the United States, residing at Spokane, Spokane County,- and State of Washington, have invented certain new and useful Improvements in Expanding Rotary Reamers, of which the following is a specication.

My present invention relates to improvements in expanding 'rotary reamers especially adaptedfor use in connection with a lead drill or bit, in the operation of drilling for water, oil, or gas and the like, either to remove a solid core orv pulverized dbris from material as minerals or rock. Simultaneously with the drilling operation of the center drill or bit at the lower end Vof the drilling tool, the previously drilled center hole is enlarged by the utilization of the laterally proJecting underreaming cutters. This enlarged hole is required for the accommodation of the couplings and of the well casing sections that are added as the drilling operations proceed, and the center or pilot hole cut by the bit is thus enlarged by the reamer which follows after the bit at the lower end of` the tool. The reaming tool is also applicable for use without the end cutting bit, and, if required, the cutters of the rotary reamer mayv be utilized for cutting the metal pipe or well casing within which the reaming tool is located. The primary object of my invention is the provision of an expanding rotary reamer by means of which many difficulties encountered in drilling operations are avoided.A Provision is made for forcing the reaming cutters into expanded operative position by hydraulic pressure from the ground surface, and the maintenance of the cutters in operative position is indicated by the free and continuous flow of water from the casing above the cutting tool, which flow or circulation continues only as long as the rotary reamers are in operative position. Means are provided for guiding and positively forcing the reaming cutters to operative position and for' retaining them in working condition as will be described. The reaming cutters are contracted and Withdrawn Within the tool by mechanical action of parts of the tool at the initial movement of elevating or pulling the tool from the casing or hole. And lubrlcation of the vparts of the tool is provided for as will be hereinafter more fully set forth.

The invention consists essentially in certain novel combinations and arrangements of parts, involvin slidable members for radially and lateray moving the reamers or cutters to expanded or contracted position, and in other features of construction as will be more elaborately described and claimed.

In the accompanying drawings I have illustrated. one complete example, and several modlfication, of my invention wherein the parts are combined and arranged according to the best modes l have thus far devised for the practical application of the principles of my invention.

Figure 1 is a vertical longitudinal section of the tool with the reamers in expanded position for operation.

Figure 2 is a similar view with the reamers or cutters in contracted position.

Figure 3 is a transverse sectional view at line 3-3 of Figure 1.

Figure 4 is a transverse sectional view through Figure 2 at line 1 4, showing the guide and retaining grooves for the reamers or cutters.

Figure 5 is a sectional view at line 5-5 of Figure 1 illustrating three reamers or cutters in expanded position for operation.

Figure 6 is a sectional view at line 6--6 of Flgure 1 at a threaded joint and showing the squared driving shaft for rotating the reaming and cutting or drilling tool.

Figure 7 is an enlarged view, in perspective, of the cutter-holder with its integral driving shaft.

Figure 8 is a view in perspective at the lower end of the upper sleeve of the tool.

Figure 9 is a perspective'view complementary to Figure 8 illustrating the upper end of the cutter-holder shell or sleeve, slotted to accommodate the cutters.

Figures 10, 11, and 12 are perspective lid modified form of the device for actuating the expanding reamers.

Figure 17 islanother modified form of the expanding and locking mechanism for the reamers, and Figure 18 is a transverse sectional view of the locking device, at line 18-18 of both Figures 14; and 17.

For convenience of illustration the wellcasing and the center drilling bit are omitted from the drawings, but it will be understood that thetool is suspended within the well casing by means of the threads at'the nal opening 2 of the coupling member extends throughout the length of the drilling tool, as will be described, and water under pressure is forced through the drill rod and tubular tool for expanding the reamers. At its lower end .the coupling 1 is enlarged to form a cylindrical head 3, and this head is packed to form a piston having relative movement within a cylindrical sleeve Il. A packing nut or gland 5 enciroles the couplin member and is threaded, as by left han threads into the upper open end of the sleeve 4. `A cylinder head 6 is formed of an annular, interior flange on the cylinder 4, and between the piston 3 and head 6-an annular water chamber 7 is fashioned which communicates with the bore of the coupling 1 and drill rod through port 7 in the coupling. By means of water. pressure flowing through the bore 2 and port 7 into the water cylinder 7, as hereinafter described, the movable parts of the tool, by pressure applied to the head 6, are elevated from position' of Figure 2 to operative position of Figure 1, thus expanding the reamer.

The piston portion 3 is provided with a packing ring 8 to revent leak of water from 'the cylinder 7, an it will be understood that the piston remains stationary as the tool is elevated.

Below the sleeve 4 is located the barrel 9 which is secured to the sleeve by yleft hand ythreads 10, and this barrel, as best seen in Figure 9, is'provided with a plurality of diametrically arranged, open end slots 11, 12, and 13 at its upper end, and near its lower open end an interior flange 14 is fashioned. This flange has a squared opening therethrough in line with the central axis of the tool to receive the squared drive shaft 15 formed integral with the cutter holder 16. The cutter holder is cylindrical and occupies the space within the barrel 9, and is secured to the lower end of the coupling 1 by means of the threaded boss 3 thereonl which threads into the socket 16 of the holder. 'llhus it will be seen that the barrel 9 which encases the holder is slidable relative to the holder, but rotates with the holder through the drive shaft 15 and the complementary squared flange 14. The cutter` holder is fashioned with a series of undercut grooves 17 complementary to the slots 11, 12 and 13 of the core barrel. These grooves extend longitudinally of the holder and are vertically disposed in the tool having curved inner walls and undercut edges forming guide flanges 18 at the sides of the grooves. rllhe grooves increase in depth from the top edge of the holder to the bottom of thegroove, .as best seen in Figure 1, and are adapted to receive a set of reamers or cutters indicated as 19 in Figures 10, 11, and 12., Each of the cutters has a top, rounded flange 20 and bot- .tom flange 20', and side flanges 21 the latter fittin under the flanges 18 of the grooves 1 which guide the cutters as they move with relation to the holder and also retaintheni in position. lin inoperative position these cutters rest in the lower enlarged parts of the grooves 17 of the holder with their working faces projecting into the slots as 11, 12 and 13 of the barrel, as seen in Figure 2. When the tool is actuated by water pressure to expand the cutters, the rising core barrel lifts the cutters, and they ride upward in the grooves which guide them to the tops of the grooves. As the cutters are elevated they are alsok rojected lat erally and radially and by t e time they have reached the tops of the grooves the cutters are projected through the slots 11, 12 and 13, to operative position as in Figures 1 and 5. ln this position the top flanges 20 are retained in complementary recesses 22 in the head 3 of the coupling 1, and the bottom flanges 20 of the cutters are forced against the inner wall of the barrel 9 and clamped between the barrel and the holder,

as in Figure 1. The lower end of the squared driving shaft projects into a sleeve 23 with a squared flange 23 similar to the barrel 9 and attached thereto by left-hand threads 24 at the upper end of the sleeve and the .lower end of the -barrel, and below. this sleeve'is attached the coupling head 25 by right-hand threads 26. The coupling head is hollow and provided fwith. an enlarged chamberv25 for Water.' 'llhev squared driving shaft in combination with the squared flange insures a positive 'drive on turning movement adording' extensive wearing surfaces and great strength, though a key or spline might be used.

For limiting the movement of the sliding parts of the tool l utilize a` stop nut 27. threaded on the lower endroita the squared driving shaft, and in addition to performing its function as a stop, this nut also af-I Lesaeea interior grooves 30 to render it resilient and is located just below the sleeve 28. rlhe lower end of the sleeve 28 is fashioned with an interior flange 31 forming a shoulder against which the head 32 of the valve casing contacts to limit downward movement of the valve casing within the sleeve.

lVithin the lower end of the tubular valve" member or valve casing is retained a. ball 33 adapted to close the seat 33 in the valve casing when forced to its seat by water pressure from above, which may flow down throu h the drill rod and tubular drilling tool. n the exterior of the valve case or casing, near its lower end is secured a bushing 34, as by set screw 35, and the upper end of this hushing is fashioned with a reduced extension 36 having a rounded top edge and adapted to enter and expand the resilient clamp ring 30. When the tool is inoperative, this resilient clamp ring 3() is clasped about the expander or extension 36, as in Figure 2. When Iwater pressure is applied to the tool to expand .the cutters 19 to operative position, the valve casing is first moved downwardly from position of Figure 2 to that of Figure l. This movement slips the expander 36 out o the clamp ring 30, which ring is resting onthe inset ring 34 of the coupling head 25, and the expanded clamp ring immediately contracts and clasps the valve'casing, as in Figure 1.

ln the lower'end of the valve casing are lateral diametrically extending ports 37 which also pass through the lixed bushing 34. When the tool is in inoperative position these ports are closed by the wall of the chamber 38 above the enlarged chamber 25 .of the head 25, but after the tool has expanded to operative position, the ports pass from the small chamber to the larger one, and water is then tree to tlow trom the valve casing through the ports 37 into the chamber 25 and thence into the hole beneath the tool. The bore oit the shell 23 is designated as a chamber 39 in which the nut 27 on the end of the drive shalt is adapted tol reciprocate, in the expanding and contracting movements of the tool. @n the lower end of the barrel 25 are 'threads ll0 to which the pilot bitV or lower. drill is attached, said drill not being shown in the drawings.

The cutters or reamers 19 may have a variety of cutting members as diamond cut.- ters indicated at 2()a in Figures 10 and 11, or the cutting faces ot the cutters may vary as in Figure 12 to adapt the cutters or reaniers for various kinds of work.

ln preparing for drilling operations, be-

fore the tool is entered in the well hole, the cutters 19 are secured in retracted position within the core barrel 9, by pushing up the valve casing so that the expander 36 will enter the split clamp ring 30, and by means of the frictional engagement of the expanded clamp ring on the expander, and the fact that the clamp ring is seated on the insetring 34 the tool holder is retained in the upper end of the barrel." 'lhe coupling head 25 is then threaded into the lower end ot the shell 23 and the tubular coupling 1 is connected to the lower end of the tubular drill rod not shown. rlhe tool. attached at the lower end of the drill rod is now lowered into the hole, or casing, and successive drill rod sections are added until the tool has reached the desired depth at which point the reaming is to take place. lt necessary, water under pressure maybe forced through the drill-rod and tool (the ball, valve 33 being absent) to wash away the dbris and providing for progress of the center drilling bit until thereamers or cutters have reached a point below the lower end of the lowest well casing or section. The water connection is then removed from the top or surface end ot the drill rod and the ball 33 is dropped through the tubular drill rod and tool to rest upon its seat 33' in the valve casing or slide valve 29, thus closing the lower epd of the tool against passage of water. l/Vater under pressure is then discharged down through the tubular drill rod and into the tool, forcing the ball valve tight against its seat. A pressure of between 150 and 500 pounds will be suicient to force the slide valve from.

its position in Figure 2 to that ol Figure 1,

releasing the split clamp ring from its grasp on the expander 36 and forcing the head 32 of the slide valve to its seat 31 in the cylindrical sleeve 28, thus stopping the movement of the slide valve. rllhe split ring at this time has contracted and embraces the slide valve, and its diameter is sulliciently reduced to permit it to pass into the bore 38 of the coupling head 25. Before the port 37 in the slide valve is uncovered', the pressure of water through the port 7 in the sleeve 4 enters the cylinder 7 or chamber in this sleeve, and upward pressure against the head 6 will elevate the parts 9, 23 and 25 and parts carried thereby, expanding the reamers or cutters as heretofore described. As the tool is lifted the coupling head l, tool holder or cutter holder 16 and the squared shaft 15 remain stationary, and the port 37 is finally uncovered. lWater is now released from the interior of the too-l and iows through port 37 into the enlarged chamber 25 and thence to the bottom of the hole. rlhe reaming cutters are now in operative position and the tubular drill rod is revolved to impart rotary motion to the 'cutter holder 16, the cutters or reamers 19 and the entire :ik J1 toolD Circulation of Weiter is provided for through the irill rofl, the tool7 enel npvvsrcl from benentli the tool7 esteriorly tliereo, pest the rotetingg reemers i9., wliere cutgs or clloris are carrieel upwztrtlly tlirouggli tno well liole or cesing tlie surlece of the gronncl Tlie release ofi @veter through the port or ports 37C andthe continued. circulntion of 'We/ter es eliove described intlicstes tliet tlie reeiners in expended working position; entl it will else be eppoi-ent tliet ell clovvnvvortl press-nreesenteil on tlie clrill the lower enel of tlie tool will lieve tendency to maintain the remmers in ope`r etive positionn llie reemers ere tlius loeclrecl egoinst e soliol support enel tlre liolcler lo celtes tlie leterel tlirnst imposecl on tire reemers enel port or tlie die@ vvliile tlie grooves titl snol slots rvliicli eccommodlete reemers receive e pel-rt ot tlie rlrsg streins ol tlie reemers.

Alfter e section of the liole lies 'been drilled endl resrned loy tlie progressive9 tloivniverrl movement of tlie tool., the circnletion et vreter is stoppecl loy cutting cti tlie supply to tlie drill roel., Alfter cutting oli' the water pressure, the drill rorl snol its tool ere pulled from the Well liole in usuel mennen At tlie initial elevating movement or tlie clrill rofl enel tool, tlie suspentlecl parts el, il, 23, 25 enel rlconnections together Witli. tlie ettecliecl pilot or center drill, ere byA their Weight, lieltl stetionery,'vvliile tlie olrill roel, tlrill liolrler lo, its sliett l5 ond connections are relatively moved7 Slioulol the 'Weight ot' tliese "parte loe insuicient lor tlie purpose, contact ot tlie expended resmers l@ with tlie lower enti of tlie ivell casingi vill liolcl tliese ports in stetionery position, While tlie rlrill roel coupling, rentner liolrle'r snel sqnorerl sliet nre elevetetl.. llne movement ofi tlie groovecl holder conse-s tlie remmers loe reti-noted or witlirlrevvn from tlieir projecteel position in tlie slots ll, l2, ll, enel es tlie lrolcler rises tlie or cutters ere linslly sestecl in tlie 'bottoms ol ie grooves vvitli their 'working feces ivitlirlrewn within. tlie slots ll, l2, i3. The nist 2'? is to tlie tez i 59,3, ceri-ying; witli it tlie slicle valve 39? the vulve, c p ring;1 550 snol sleeve 28 tne nut retnining their seine reletive positions es in it -gir-re l llie arcuate @grooves in Yie remmer liolcler @intl inoperune,

reen/1ere, `lie slide vslve in tliis instance, indicatori es l2 is e comparatively long tube leaving; e slide movement in the tool es incliceterl liy tlotteol lines et tlie lower enel oi" the slitle valve. ll-lere o flanged liescl 27 is tlirceclerl on tlielower enel ot the squared shaft in place ot tlie nut 27 of Figure l, enel tlie heeel lios on open flange 43 et the lower enel ol tlie squared slmitt The slide valve eiitencls tlirougli this :Hnge enel also projects into tlie drill rool coupling; l5.

,llflien liyolrenlic pressure is lirst epplieol. preparatory to expanding the reerning cut-- ters, the later-el port 4:6 in tlie coupling heed l5 remains closecl until liytlreulic pressure forces the slicle Valve down releasing the clamping ring and cmisirngj the annular, eX- terior shonller i7 to engage the Flange 43. By tliis time the upper enol ot the slide valve lies uncovered later-el port i6 to sclmit Water i pressure loeneetli the heed 4l of the sleeve 4:8. But tlie slirlslole parts ol tlie tool are not elevated until the split clamp ring t9 lies relessecl tliem. This ring is similar in construction to the ring 30 but is locatecl in e different' relative position. lt is retained ivitliin en ennuler groove 50 in the coupling lionel 'l5 and lies e number ol clistending,1 pins 5l located in rsolislly extendingia complementary sockets in the lieecl. 'llie elasticity et tliis split ring liolils the pins Witli their inner pointed entls in contact with the exterior surface oi tl'ie slide velve l2, neer its Upper enel, snol in this positionJ tlie split ring is lielcl clistended or expended. l/lliile in retracted or inoperative position tlie iesmers ere locked one relative movement ot tlie sliding; parte of the tool snol tlie tool holder is prevented; loeceuse tlie split ring is sentori on en annuler 53 ot tlie sliell 5l. llllien tlie slicle vslve is pusliefl' clown trom position ot Figure le its upper enel is tv'itlrclrevrn from contact with pins 5l split ring is contrecterl clue to its elesticitys ln its contrectecl position tlie split ring is enclosed Witliin tlie annuler groove enel :l from sees-t on tlie 539 tions permitting liytlrenlic pressure to en oentl te roaming cutters to operetiveposie enpsnsion movement oit tine reemtlie contraction movement tio-e are etteineti by the action es l snol Q.

c le e zlnrt nionlice n oit c ing)ya ineens Jfor lioloing rs in inoperative position illusn o connection l s lower endiol lll@ with geese to holcl, teinp(nfzniljyv the cong pling head 60 its requiefl clistenee lnelovv the 'need 64e o1 the tlneeecl bushing 65. This bushing is shouldered et 66 to receive the isnge 67 of the valve heed, 56 enel the bushing lies external threads toi.' tlie sleeve 68 within the shell 6l. )in Figure 16 the slide valve, which pieviously lied been held in elevated position, by grease packed as tlirougli the grease port 69 in the Well of the diill holden oi: heeel '30, lies been olepiessed by Water piessme in the slie valve And tlie heeel 56 oi: the valve lies been moved from contest with the lowes enel of the squared shaft l5. This movement llas pnsliee the peeking 1fing 59 pest the moutli oi outlet opening et the grease port 69 enel in tlie position showin continued liydmulie pi'essnie on the bell 705 causes e beek or upweicl piessin'e in the tool for lifting the heed 6 of Figure l. Pressure on the heeel 6 elevetes the slidingn petits of the tool to expanii tlie teeming entteis and the gi'esse in elisniliet- 63 is foieed out es the niemnei 5G is elevated in Fig 16.,

This foin of tlie invention is especially' adapted for oliilling eompsiatively shallow wells5 and the grease paeliecl in, its chenille?7 with the valve elevsteci sufeiently to close tlie outlet port 695 ifeteins tlie euttei's oi ieeniers in looked inoperative position until the lively-eolie pessuie is epplie as here toitoie Clesefiloed;

ln liguies 17 enel l e further moiiiestion ot tlie tool is illustrated combining the comparatively long slide valve and resilient ring of nice les Witli the expanden enel, iresilient ting el Figures 'l snel 2. The action of the tool nnei liyelmulie pressure, in this instenee is the saine es that pteviously tieseiioeels lont the duplex resilient oi elastic Clamping `sings Whieli look the parte in in ope-native position liolcl the parts more seeuely and support e loew/ietF loeolg l From' tlie shove eieseription taken in conn on with my citeer/ings it vwill be eppen- Llie tool es suspended from tlie shaft, is temporarily loosen-7. v-Jitli tee reenies oi eutteis in inopeetive nosition in otflei' that the tool may be into tite Well easing oi hole. 'lllie nets se positively enpendeel oi* projeeo by liydieulie presgea .1 4.1 snfe siglo, Steele position 1* 1 ,m ttin: i ioo eno tool efe le volv setiseteo; to inopeo convenience met it may e te ities ie process o;

nii outsole ln eerliei eonstiuetion itwes impossible to keep geit or i'oelt particles tem entesm ing the bestel, 9 anni Wearing the gtooves enelv feces? sn even elioliing the barrel so that the cutteis could not function.. lt Wes 7 also impossible to piroteet tlie oeiloons oi"- elieinonds fiom being broken? tlispleeecl enel lost ln the present eonstiuotion tlie onto ters lit exactly in the slots in tlie bestel keep-1 ing out ell foreign metter enel tlitongli the functioning o the menate gnieie tlie euttets are ietraeteel enel tipped so that tlie pteeious stones are guarded ami pioteete Having tlins fully oleseiiloetl my inveitn tion, what l eleini es new and @lesite to sed eure ley Letters Patent is* l. 'llie combination with relatively stem tionei'y hollow euttei liolen en hollow drill rofl, oie movable tool including teelieily enpensiole teaming mettete enel ineens tot admitting hydraulic piessnte to the tool for expanding seid vteeming entteis 2: The eonibinetion with e elsitively' stetioneiy hollow enttei holden enti elisil oi a suspended tool enel ineens tot one miily holding saisi tool in suspensiwi9 ineens tot admitting loyelreulie @fessure the tool Wlieieoy the lette? is ,mov-eil to @ptetn etive position,

3, The combination in e i` i:i".ng too @lading e rotary coupling 'heeel .hollow cutter liolelei enel' enpsnsilole entteis een iieel thereby, ont s Totem] too-l soepen@ n' seid coupling heed, ineens fot f flieulie pressure to the toole en ineens Wlieieby tlie tool is moved relatively to liolciei1 oi" expanding seid veuttetss t. The combination with a teletively tioneiry hollow till-tool coupling enel ontn tei holder' forming e eliivi monili-ei: een-J neeted thereto and e heed. oi the een 'l of e tubular slieizilole tool? est sensible euttets ee'fiied by seid holden5 e lieeo on. tlie tool means for teinpoietily ieteining tlie tool in sus'peniieol position? eno eens Een admitting hydraulic piessnie l Lveen seid liesds tot moving the tool ent-tees to operative position 5. lie combination in e tots with e tubular eouplinff heed enttei" le enti eutteis and e polygonal f l im..

iiietion soup linr1 co-acting means on the holder and tool member for laterally projecting said cutters lovv grooved holder and cutters therein, of

a slotted movable member forming part or said tool and engaging said cutters, and means for admitting hydraulic pressure to said tool for moving the latter and expanding said cutters to operative position.

"8, The combination in a ieaming tool including a rotary tubular coupling head, a hollow cutter holder and cutters carried thereby and an integral drive shalt, ol a hollow sectional tool member suspended from said head and operatively connected with said shalt, means lor tem orarily sus'- pending said tool and locking t e cutters in inoperative position, and means actuated by hydraulic pressure lor releasing said loclring means and moving said tool member to expand said cutters.`

9. rllhe combination in a rotary roaming tool with a tubular coupling head, a cutter holder having a polygonal drive shalt, and

expansible cutters carried by said holder, oty

an upper sleeve on the coupling head torminn1 a head and cylinder adapted to receive Water pressure from the coupling head, a slotted barrel connected with said sleeve and encasing the holder, a shell connected with said barrel and encasing said shalt, a lower couplinen head connected with said shell, means ror supporting said sleeve, barrel, shell and lower coupling from said tirst mentioned coupling lhead and means Whereby, when said members are suspended by Water pressure in said cylinder, the cutters are expanded.

lll., The `combination in a rotary roaming `tool `with a longitudinally grooved cutter holder a cutter in said groove, of a relatively movable slotted tool member encasing and adapted 'to engage said cutid move it' 'to radially extended posination in a rotary th cutter holder having lonfi tending exterior groove increas' h tovv'wf'd one end, et cutter said cutter through ry movable slotted to cutter, l

said member to pr l position.

ion in rotary reamer cutter der l ying en exterior untlanges, `l

bil@

f having lateral i r. fr aiolguide Menges, a

i EO'Ol.

Mannes for moving said member to project the cutter to operative position.

13.. 'llhe combination in a rotary expansible reamer with relatively stationary tool supporting memberso tubular constructionand relatively movable tubular members, and means for expanding the tool to operative position by hydraulic pressure, ol means lor supporting the movable members vvith the tool in inoperative position', said means being releasable under hydraulic pressure.

lll. The combination in rotary enpansin ble reamer having relatively stationary tubular supporting and driving members and movable tubular members (3o-acting therewith to expand the tool to operative position under hydraulic pressure, of a slide valve operatively connected with the stationary -and movable members, and means 85 tro-acting with said slide valve or temporarily locking the expansible reamer in contracted position.

l5. r)The combination in a rotary roaming tool with tubular supporting and driving members, of relatively movable tubular members adapted to co-act therewith for expanding the tool to operative position under hydraulic pressure, a tubular slide valve connecting the stationary and movable members and adapted to resist hydraulic pressure, means for temporarily holding y saidvalve to maintain the tool in inoperative position, and said holding means being releasable under hydraulic pressure.

16. lhe combination in a roaming tool With a stationary supporting member and movable driving member as described., of a tubular slide valve operatively connected with said members, ring adapted to tempore ily i in locked position 'for the pu li. The combination vith stationary supper-tir driving members as descr slide valve connecting detachable loelring mem er cf' valve adapted hol? inoperative positiono i8. 'lhe combination with I stationary snj A.ng asicesci slide valve sup member eng a resilientl clamp by movement oif said t able member i0, The oon natio tool with ho Leeeea able tool member for radially projecting said cutters to operative position.

20. The combination in a rotary reaming tool with a longitudinally arcuate grooved 5 cutter holder and a flanged cutter operative in said groove', said cutter havin top and bottom flanges for engaging tie cutter holder and a movable slotted tool member respectively, of a relatively movable slotted tool member encasing said holder and 10 adapted to engage said cutter ard move it to radially extended position.

In testimony whereof l aflix my signature.

FREDERICK STONE.

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