US1819367A - Expanding rotary reamer - Google Patents

Description

Aug. 18, 1931.*v A.1.. GRANT 1,319,357.

v EXPANDING ROTARY KEMER Filed Feb; 14... 1928 2 .':heeczf-Shept4 ,1

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ug. 18 1931. l J. GRANT 1,819,367

lEXPANDING ROTARY BEAMER FilledAFeb. 14, 1928 2 sheets-snee: 2

Patented Aug. 18, 1931 PATENT oFF-ice i' i JOHN GRANT, OF LOS ANGELES, CTALIFORNIAy EXPANDING' ROTARY BEAMER Application lfiled February 14, leas.. serialv 110.254,'266.

This invention has relation to expanding rearners or underreamers, or similarexpand ing tools particularly adapted for well work; the invention contempla-ting and characteristically consisting of certain improvements in that type of reamer which is set out in the application of John T.` Phipps, Serial No. 61,808 filed October 10, 1925. The reamer described in said `Phipps application is characterized by a substantially tubular slotted body within which there is a longitudinally extending central mandrel. The cutters or cutter carries play in the slots and extend through the body wall and by relative longitudinal movement, with relation to the man# drel, and propelledby a spring actuated propeller, the cutters are moved outwardly or expanded; their outward movement, when moved longitudinally, being due to interengaging conformations of the mandrel and cutter carriers which cause expansionand al. low contraction.V In that Phipps underreamer,'as in the one now about to be described, relative longitudinal movement between the mandrel and cutter-.carriers ,y is eiected by longitudinal movement of the carriersl in the body.v And also inthat Phipps construction the cutter carriersare propelled by a propeller surroundingthe mandrel or an extension yof it and by ak springy which likewise surf rounds the mandrel or its extension, and the water: course is -in the same mandrel. Y j

The above described features of the Phipps un derreamer are included'in the underreamer of the present invention; the improvements concerned in this present invention,referring to the mounting and bearings of thecutter carriers, the interengagin'g conformation of the carriers and themandrel and body,'and various other improvements havingparticularly to do with the carriers and cutters. These various improvements will be. bestr understood from a detailed description 'of prerferred and illustra-tive designs, rather than from general preliminary deserptionot their natures, and I, Vaccordingly proceed witha detailed description of specilic illustrat-ive vembodiments, f the invention and for this purpose refer to the accompanying drawings, in which v Figur-e1 is a central longitudinal section ,of my improved vreamer showing the parts in their contracted or collapsed positions.

Fig. 2 is a similar view showing the parts in their expanded positions. y

Fig. 3 is a cross-section on line 3 3 of Fig. yl.

Fig. Fig, l.

Fie.

Fig. c

Gis a cross section on line 6 6 of 4 is a cross section on line 4 4 of 5 is a cross section on line 5 5 of ig. ,7 is a cross sectionon line 7 7 of Fig. 8 is a somewhat enlarged side elevation eta carrier equipped with a roller'cutter. 'p VF ig. 9 is a central vertical section of the carrier shown in Fig. `8. i f

F 10'is a central vertical section.

Fig, 1l is aV plan of a `preferred lform of protective washer which is shown inthe other igures. l Fig. 12 is av .vertical central ysection showing a moditied'form otroller cutter mounting in carrier, `5 c Fig.v 13 is a cross section on line 13 13 oi Figl12.; g

14 is across section online 14- 14 of Fig.y12, and.

'Fig'. 15 isv aninner Vface carrier .shown inFig. '9. l Y y f, In .the v drawings a. .substantially tubular bodyl() is illustrated suitable for the design of reamer which l have chosen here to describe as illustrative of the invention. This body has a central longitudinal Abore 11 which may preferably be of `uniform size from the top 'of the body down toy a point near its lower end Where the bore is reduced in size as at 12.

elevation of the At the lower end of the body the usual taperthreaded box 13 is provided for taking the tool oint pin 14 of the usual drilling bit 15, the drilling bit having its usual or any suitable water course or courses 16 to which water or other circulating fluid is supplied through the central mandrel 2O and its extension tube 21. This central mandrel 2O Vdepends from the upper end of the body where it is crew-threaded into the body with a taper-threaded pin 22, the mandrel extending above the upper end of the body in the form of a sub 23 which may be adapted (but not shown in the drawings) for attachment to the usual rotary drill stem. Th-e mandrel throughout its length is provided with a longitudinal water-course 24 which water course is extended through the tubular mandrel extension 21 to a point near the lower end ofthe body. The mandrel extension 21 may be made, in effect, integrally with the upper part of the mandrel. But it is convenient to make the part 21 as a separate piece and join it to the mandrel by fitting its upper end into the lower end of the upper mandrel part, as illustrated particularly at 25 in Fig. 1. This joint of the tube 21 with the upper part of the mandrel may be more or less tight, but is not necessarily so tight that the tube cannot be easily removed. It is, however, preferably fitted tightly enough that to all intents and purposes the tube forms a physically rigid extension of the mandrel; and it thus may be regarded as a part of the mandrel. The lower end of tubular extension 21 preferably lies closely above the tool oint pin 14 so that if the mandrel should break the lower end of its extension, resting upon pin 14, will support the mandrel substantially at its proper elevation in the body and keep the topl in operative condition even though the mandrel should be broken completely through at a point below the taper-threaded joint at 22. From the description that follows it will be seen that the mandrel, even if broken, is held in central position by the cutters or cutter carriers. Also to prevent any liability of mandrel breakage by vibration, the lower end of tube 2l is confined inside a spring seat collar 30 which fits in bore 12 and rests upon tool joint pin 14. The fitting of the lower end of tube 21 in collar 30 may be made more or less tight if desired, but it is preferred not to make the collar 30 fit too ltightly in bore l2 or to make the tube lit too tightly in the collar as the disassembly of th-e reamer is thereby facilitated. V

The cutter-actuating spring 31 rests at its lower end on collar 30 and at its upper end it supports a cutter propeller 32 which is here shown as. cylindric in form and slidably fitting in the lower part of bore 11. This cylindric propeller 32 vis of a length somewhat greater than the upward stroke of the propeller so that, when the propeller is-in the position of Fig. 2, its lower end is still somewhat below the lower ends of cutter-receiving slots 33 and thus prevents the entry of mud or silt through the slots into the lower part of bore 11 in which the spring 31 is located. The spring chamber is thus substantially closed off against entry of the mud or silt which might otherwise lill the spring chamber and clog the spring action; and to continuously wash out the slight amount of silt, which would otherwise enter through clearance spaces, I provide for carrying a certain amount of the water circulation through the spring chamber. It will be noted that the open lower end of mandrel extension 21 is in communication with the circulation passage 16 of the bit. Some of the circulating water may pass from the lower end of tube 21 up into the spring chamber and thence out through discharge passages 35 under the cutters when the cutters are expanded and propeller 32 is in'lifted position. But to provide for free circulation of a considerable amount of the circula-ting water through the spring chamber, I may provide perforations 36 in tube 21.

In the particular design here illustrated the mandrel has a cylindric upper part 40 at whose lower end there is a conical or diagonal shoulder 41. Below this diagonal shoulder 41 the mandrel has a reduced cylindric part 42, and below the cylindric part 42 the mandrel has a conical or downwardly tapering part 43, this last part being of comparatively slight taper. y

The number of cutters and cutter-carriers utilized in my reamer may be as desired, the number being largely a matter of choice. I have found, however, that three cutters are very well adapted to perform efficient service and I therefore illustrate three cutters and cutter carriers here. Thus the body is provided with three longitudinally extending slots 33 and in each of these slots there is a cutter-carrier 50, the formation of whiclr' shall now describe. Broadly speaking it is immaterial, at least as to the major characteristic features of my invention, whether the Vultimate cutting element or cutter in an integral part of the cutter-carrier or is provided as a separate part. Thus the ultimate cutter may be in the form of a cuttingr edge formed upon the cutter-carrier itself; but for purposes of typical illustration I here prefer to show the ultimate cutters in the form of rollers 51 mounted on pins 52, which extend longitudinally of carriers 50 and are mounted at vtheir upper and lower ends in lugs 58 and 54, which extend outwardly from the body of the carriers. The details of this mounting will be considered later, it being sufficient now to observe that the outer longitudinal edge of the roller 51, and therefore they axis of pin 52, if the roller 51 is cylindric, has such relation to the bearing surfaces of the carrier (the bearing surfaces that bearv against the mandrel and the body that when the Cutter is eollapsed or retraete as in Eigl, its outer cutting edge stands substantially vertically or substantially parallel to the eentral ver-tidalY ,axis of. the whole tool; while it stands in atilted ,posinon when expanded, asin Fige The,- outter-earrier Qlias an inner lower mandrel engaging fase 55 which. stands sub.- stantially vertieally when the Carrier is in the position in Eig. l. These 55 ofthe three carriers. are parts of eonie suraee whose diameter at the lower ends ofthe carriers is substantially or eXaotly the saine as the, diameter of the extreme, lower end ofthe tapered niandrel part 4:3, These slightly taT pered eonio bear-ing fases 55 are of substans tially the sanie length as that of the tapered mandrel part 43, and their diameter at their upper ends is substantially or exactly the same as the diameter of the mandrel at the upper end of tapered part 43; S0 that when the car.- riers are in their upper positions these conic bearing surfaces 55 surround `the tapered mandrel part 43 andbear inwardly against it at all points, These features will be' unf derstood best by a consideration of Figs. 2, 6V

and 7.

The upper inner bearing surface of each Carrier is ar eylindrie surface 56 of the .saine diameter as the upper eylindrio part 20 of the mandrel.. When the'carriers are in .their upper'and expanded positions, these eylindre bearing faces. 5.6 are situated eenT eentrieally about'the central vertical axis of the mandrel and stand in a vertical position, and therefore bear inwardly against part e0 of the ynaandrel as ,is shown in Figs.. .2 Yand 5- When the Carriers are in their lower and collapsed positionslthese eylindric bearing faces" ad, due to the fact that the Carrier swings inwardly at its upper end to reach eelT lapsed position, stand somewhatout of the vertical position, as is best illustrated in Fig., l- The oylindrie bearing faces 5G are atleast aslong as `the vertical distance he, tween the upper ends of slots 83 and the lower end of oylindrie mandrel part di), so as to give the carriers a full and true inward bearf ing on the mandrel at their upperends. l The oylindrie bearing fases may, however, extend below the mandrel shouldery al when in, the position Of Fig. 2. .The lower ends of cylin-r dric faces are `joined up withthe upper ends of conic faces by curved surfaces 57 of any suitable conformation.

lEach of the carriers is provided with ver; tieally extending wings d0 at the inner edges of its sides, these wings overhanging the side edges of slots 33 to limit the outward moves niente of the carriers by bearing against the wall of bore 1 1 at the longitudinal sides of the slots, faces 6l .which` are adapted to bearfthroughout their lengths against the wall of bore 1.1, Y

The wings have outer eylindrio riers and, like those faces 56, make a slight angle with the vertical elements Vof oonie fades .55 and with the cutter 5 1. This :inguV- lar relationship isperhaps best shown in Fig. 8. The angle, as will readily be seen rfronti a consideration of the drawings, is the angle of tilt ofthe cutters.

The wings also have inner bearing faces 62 which lie in vertical planes radial to the central axis of the mandrel when the oarrers are in the collapsed position in Fig. 1; and these inner radial bearing faces 62 of the several carriers bear against each other at their lower ends, and preferably throughout their entire vertical lengths when the carriers are in their collapsed positions. When in collapsed position the lower ends of the carriers thus bear or abut circumferentially against each other around the man,- drel, but without touching the mandrel part 2l; and also the lower ends of the outer bearT ing faces 6l are bearing` outwardly against the wall of bore l1, This feature may be seen illustrated in Fig. 4s. Consequently the up ward movement ofthe lower end of each cutf ter-carrier is purely a movement of vertical translation, the lower ends of the carriers having no lateral inward or outward move.- nient.k rlhe lower end of each carrier inerely moves straight upwardly while the upper end of each carrier moves upwardly and tilts outwardly. This Outwardtilting of the upper end of the carrier is permitted by the fact that the outer cylindric bearing faces 61 of the wings are vertical when the carrier is in tilted position-that is, the wings 60 are narrower at their upper than at their lower ends, and the` wing thickness at the upper end is just suchas will fit snugly between' the wall of the bore` 11 and the upper large cylindric part 40 of the mandrel.

Y Thus, in operation, the action of spring 31 and propeller 32 is to push the carriage upwardly, pushing the upper beveled end surface of each carrier` up against the bev.-

eled annular mandrel shoulder Lil. By this action the upper ends of the carriers are first forced upwardly and outwardly until the carriers are tilted and the upper endsvof the carrier bearing faces 56 (then in vertical position) will ride over cylindric mandrel part 40. Then the further action of the spring and propeller 32 is to push the tilted carriers directly upwardly to the position of Fig-2.

ies

The cutting rollers 51 are mounted on their vertical bearing pins 52 whichas I have said before, are mounted at their upper and lower ends in the outwardly projecting lugs 53 and 54 of the carrier, the rollers being confined longitudinally between these lugs. In order to hold the pins 52 in place longitudinally, they'may be provided at their lower ends with a circular groove 7 5 into which a transverse pin or dowel 76 fits; and in order to prevent rotation of the bearing pins 52 their upper ends may be provided with eccentric heads 77 which fit into eccentric bores 78 in the upper lugs 53. The rollers 51 may either be cylindric as shown in Figs. 1 and 2, or they may be conic or partly conical, as shown in Fig. 12; and they may have their exclusive rolling bearing upon the pin 52 or, asY

particularly illustrated in Figs. 12, 13and 14, they may have auxiliary rotary bearing faces engaging directly with the body of the carriers. Thus, as shown in these last mentioned figures, the upper and lower ends of the rollers may be provided with cylindric smooth parts 8() which fit back against the semi-cylindric bearing faces 81 provided on the carrier body. The grooved or toothed main part of the roller itself will, of course, have no direct bearing against the carrier, but will have a small clearance in front of the eylindrie front face 82 of the carrier. But the provision of the bearing faces 80, 81, acting directly between the carrier and the "ends of the roller cutter, is designed to take a considerable shearing or bending strain olf the bearing pin 52.

Another feature of the invention in connection with the carriers and cutters is shown in Figs. 1 to 11. INhen a reamer of this type is being lowered through a well pipe, the constant tendency of spring 31 is to force the cutters upwardly and outwardly against the wall of the pipe; and consider-able wear on the pipe and on the cutters may result. The outward pressure of the cutters on the pipe is augmented by the upward dragof the pipe on the cutters. I have provided a simple means for Aobviating at least a great deal of such wear; and, applying this means to the form of reamer here illustrated, I have provided a form of wear-washer 90 which is shown in the various figures, but is perhaps best illustrated iu Figs. 8 to 11. rIliis wearwasher will either be in the form of a washer placed around the bearing pin 52 at its upper end and above the roller 51, or in the form of a clip placed upon the upper lug 53. The design shown in the drawings contains both such features, being in the form of a flat metal strip or bar bent or otherwise -formed substantially to a U-shape to fit over thel upper lug r53; Vthe lower leg 91 ofthe lai-shaped member havinga hole 92 to pass the pin 52, the upper leg 93of` the U-shaped member having a hole 94: to tit over head 77 -ofthe pin, and the outer web 95 of member 90 being shaped to bear against the" outer face of lug 53. IVhere this member 90 is thus made to fit over the outer face of lug 53 the member n 90 isV provided witha diagonal upper and outer casing engaging face 96 so that engagement with the lower end vof the casing will move the upper ends of the carriers both downwardly and inwardly. Vhere the wearwasher or member 90 is not used, this diagonal face is applied directly-to the carrier itself, 'as shown at 96a in Fig. 12. The outer face 97 of the member 90 is` arranged to be at `least as far out as the eXtreme projection of the cutter 51; and it may 'preferably project a little beyond the outermost face or cutting edge of cutter 51. In such a position this outer face of member 90 will beark against the well casing while the tool is bei'nglowered and raised, and will not allow the cutter. to bear, or at least will not allow it to bear heavily, against the casing. The member 90 may either be made of relatively hard or relatively soft material. If made of hard material, it may last a considerable period of time before having to bereplaced. It does not interfere materially with the reaming action of the cutters when in operation, because althoughV the member y9() may project even to a diameter slightly beyond the greatest projection of the cutters,'it will be understood that the drill hole at the position of members 90 has been reamed out to the full diameter of the cutters, or even to a slightly greater' diameter. On. the other hand, if it is found in any case that the members 90 interfere'to any extent with the proper cutting action of the cutters, these members may be` madeV of a sufficiently soft material that, although hard enough not to be badly worn by friction with the casing when the reamer is inserted in the hole, they will be quickly worn down or worn awayby frictional contact with the formation when the reamer is in operation. In any case the washers may be easily renewed as often as desired.

I claim:

1. An expanding reamer, comprising a tubular body7 having a slotted wall, a cutter carrier movable transversely in the wall slot for expansion. and contraction, a longitudinally extending mandrel vin the body interior and against which the carrier bears inwardly, means for causing relative longitudin al movement between the carrier and mandrel moving the carrier upwardly lrelative to the mandrel, the upper part of the mandrel having a relativelyl large'and substantially cylindric portion with `a'diagonally downwardly facing' shoulder below lsaid cylindric portion and a lower part of the mandrel having a downwardly tapered portion, and the carrier being adapted in its expanded position to seat inwardly simultaneously against said' cylindric a-nd tapered portions.

2L An expanding reamer, eomprisinga 'tu-y bular body having a` slotted wall, a cutter carrier movable transversely in `the wall slot, a longitudinally extending mandrel `in .the body interior and against whch'the carrier bearsinwardly, means for causing relative longitudinal movement between the carrier and mandrel moving the carrier upwardly relative to the mandrel, theupper part of the mandrel having a relatively large and substantially cylindric portionwith a diagonally downwardly facing shoulder below said cyA lindric portion and a lower part of kthe man drel having a tapered portion, and the carrier` being adapted to seat inwardly against said cylindric and tapered portions, the carrier having ynear its upper end a substantially vertical .cylindric bearing face and nearv its lower end a tapered conical bearingface.

3. In an en nansive reamer, the combination of a tubu ar body having a slotted wall provided with a plurality of circumferentially spaced slots., cutter carriers movable transversely in said slots, a central vertical longitudinal mandrel extending through the body interior and against which the cutter carriers are adapted to bear inwardly, the upper part of said mandrel being relatively large to cause expansion of the cutter carriers when their upper ends are moved longitudinally upw-ardly onto said mandrel part,'said cutter carriers having bearing wings overhanging the side edges of the slots and said bearing wings of the several cutter carriers circumferentially abutting each other near the lower ends of the carriers when the wings at their lower ends are in Contact with the wall of the body at the slot edges. n

4. An expanding reamer, comprising a tubular body providediwith a plurality of eircumterentially spaced slots which extend longitudinally of the body, a pluralityofgeutter carriers, one in each slot and movable lengthwise therein and transversely therein, said cutter carriers having sidewings which over hang the side edges of the slots and are adapted to bear outwardly against the body wall along the side edges of the slots, said wings being shaped so that when the carriers are in position substantially parallel to the body axis the wingsof the Several carriers circumferentially abut each other substantially throughout their lengths, and being so shaped th-at at their lower ends said wings engage the body wall but are spaced inwardly from the body wall at their upper ends to allow the upper ends of the .carriers to move outwardly, a central mandrel yhaving a relatively large' part near its upper end and onto which the upper ends of the carriers are moved by upward carrier movement, and means to move the carriers upwardly.

,5. An expanding reamer, comprising a tubular body provided with a plurality of circumterentially spaced slots which extend ally throughout their lengths, and being so shaped that at their lower ends said wings engage the body wall but are spaced inwardly from the body wall at their upper ends to allow the upper ends of the carriers to move outwardly, a .central mandrel having a relatively large part near its upper end and onto which the upper ends of the carriers are moved by upward carrier movement, and means to move the carriers upwardly comprisnga cutter propeller mounted around and .slidable longitudinally on the mandrel, and a spring surrounding the mandrel and a-ctino upon said propeller. Y

V(5, en expanding reamer, .comprising a tubular body provided with a plurality of crcumferentially spaced slots which extend longitudinally of the body, a plurality of cutter carriers, one in each slot and movable lengthwise therein and transversely therein, said cutter carriers having-side wings which overhang the side edges` of the slots and are adapted to bear outwardly against the body wall along the side edges ,ofthe slots, said wings'being shaped so that when the carriers are in position substantially parallel to the body axis the wings of the several carriers circumterentially abut each other substan tiallythroughout their lengths, and being so shaped-that at their lower ends said wings engage the body wall but are spaced inwardly from the `body wall yat their upper -ends to allow the upper endsfot the carriersto move outwardly, a central vertical longitudinal mandrel extending through the interior of the body, said mandrel having a relatively large cylindric part near its upper end .onto which the upper parts of the carriers are adapted to be moved bynpward movement, the upper parts of the carriers having cylindric bearing faces to bear against said cylindric part o' the mandrel, the mandrel having a lower tapered part of lesser diameter than its cylindric part, and the carriers having near their lower ends tapered bearing faces adapted to bear upon the tapered part of the mandrel and means to move the carriers up wardly. v y y l 7.' An yeiqgniriding reainer, comprising a tubular bodyprovided,V with a plurality .of circnmferentially spaced slots which extend longitudinally of the body, a plurality of cutter carriers tiltingly mounted in the body slots, said carriers having longitudinal side ico p carriers.

- 8. In an expansive well reamer, a body, a plurality of tilting cutter carriers in the body, means to cause tilting of the cutter carriers to a position where one of their .end parts projects further from the body than the other, cutters mounted on said carriers, and a removable wear member mounted on an outermost part of each carrier and projecting outwardly at least as far as any other point of the carrier or critter to take frictional wear against a well casing, said wear member having a smooth casing engaging surface.

9. In an expansive well reamer, a body, a plurality of tilting cutter carriers in the body, means to cause tilting of the cutter carriers to a position where one ot their end parts projects Jfurther from the body than the other, rotating rollercutters carried by the carriers, bearing pins for said roller cutters, and removable wear washers iitted upon said bearing pins at the furthest projected parts of the carriers, said wear member having a smooth easing engaging surface.

10. In an expensive reamer, a cutter carrier having bearing lugs at each end, a longitudinal bearing pin mounted in and between said lugs, a roller cutter mounted on the bearing pin lbetween the lugs, and a removable wear member in the formvof a U-shaped clip the web of which overlies a bearing lug and the legs of which lie at opposite sides of said bearing lug and surround said bearing pin.

11. An expanding reamer, comprising a tubular slotted body, a plurality of cutter carriers tiltingly mounted inthe bodyslots, said carriers having longitudinal side wings which overhang the side edges of the slots inside the body, said wings being of such form that the wings of the several carriersV abut each other and also bear outwardly against the body wall at one pointl in the length of the carriers, and are spaced from each other at another point in the lengths of of the carriers to allow inward movement of the carriers at said last mentioned point,

and means to move and support the last men-V tioned points of the carriers outwardly.

12. In an'expansive reamer, the combina tion of a tubular body having a slotted wall provided with a plurality of 'circumferentially -spaced slots, cutter carriers movable transversely in said slots, a central vertical longitudinal mandrel extending through the body provided with a plurality of circumferen-- tially spaced slots, cutter carriers movable transversely in said slots, a central vertical longitudinal mandrel extending through the body interior and against which the cutterk carriers are adapted to bear inwardly, the upper part of said mandrel being relatively large to cause expansion of the cutter carriers when their upper ends Aare `moved longitudinally upwardly onto said mandrel part, said cutter carriers bearing outwardly against the body wall, bearing inwardly against the upper part of said mandrel, and near their lower ends bearing inwardly against said mandrel and circumferentially abutting each other around the mandrel.

14. In an expansive reamer, the combination of a tubular body having a wall with a plurality of circumferentially spaced longitudinally extending slots, cutter carriers movable transversely in said slots, a central longitudinal abutment mandrel in the body against which mandrel the carriers are adapted `to bear inwardly, the mandrel and carriers being so formed that relative longitudinal movement between them causes outward transverse movement of the carriers, and 'the cutter carriers abutting each other circumferentially at one point in their lengths,v and having bearings outwardly against the body `wall at substantially the same point. Y

15. In an expansive. reamer, the combination of a tubular body having a wall with a plurality of circumferentially spaced longitudinally extending slots, cutter carriers movable transversely in said slots, a central longitudinal abutment mandrel in the body against which mandrel the carriers are adapted to bear inwardly, the mandrel and carriers being so formed that relative longitudinal movement between them causes outward transverse movement of the carriers, and the cutter carriers abutting each other circumferentially at one point in their lengths, and having bearings outwardly against the body wall ralong their lengths.v

16. In an expansive reamer, the combination of a tubular body having a wall with a plurality of circumferentially spaced longitudinally extending slots, cutter carriers movable transversely in said slots, a central longitudinal abutment mandrel in the body against which mandrel the carriers are adapted to bear inwardly, the mandrel and carriers being so formed that relative longitudinal movement between them causes outward transverse movement of the carriers, and the cutter carriers abutting each other circumferentially and having bearings outwardly against the body wall at one point in their lengths, and having bearings inwardly against the mandrel and outwardly against the body wall at another point in their lengths.

17. In an expansive reamer, the combination of a tubular body having a wall with a plurality of circumferentially spaced longitudinally extending slots, cutter carriers movable. transversely in said slots, a central longitudinal abutment mandrel in the body against which mandrel the carriers are adapted to bear inwardly, the mandrel and carriers being so formed that relative longitudinal movement between them causes outward transverse movement o-f the carriers, and the cutter carriers abutting inwardly against said mandrel, abutting circumferentially against each other, and bearing outwardly against the body.

18. In an expansive reamer, the combination of a tubular body having a wall with a plurality of circumferentially spaced longitudinally extending slots, cutter carriers movable transversely in said slots, a' central longitudinal abutment mandrel in the body against which mandrel the carriers are adapted to bear inwardly, the mandrel and carriers being soformed that relative longi tudinal movement between them causes out` ward transverse movement of the carriers, a'nd theI cutter carriers abutting inwardly against the mandrel and outwardly against the body at one point in their lengths, and abutting inwardly against the mandrel and circumferentially against each other and outward against the body at another point in their lengths.

19. An expanding reamer, comprising an elongate body having a longitudinal cutter carrying slot, a longitudinally extending cutter abutment central of the body and back of the slot and against which the cutter bears inwardly, the abutment being fixed with relation to the body,`the upper part of the abutment having a relatively large portion with a substantially longitudinal cutter abutment surface and a diagonally downwardly facing cutter expanding shoulder below that surface, the lower part of the abutment having a cutter abutment surface which makes an acute angle with the longitudinal, a cutter element movable both longitudinally and transversely in the body slot for expansion and contraction and adapted in expanded position to seat inwardly against both abutment surfaces, and means for moving the cutter element upwardly relative to the body and abutment.

20. `An expanding reamer, comprising an elongate body having a longitudinal cutter carrying slot, a longitudinally extending cutter'abut'ment central of the body and back of theY slot and against which the cutter bears inwardly, the abutment being fixed with relation to the body, the upper part of the abutment having a relatively large portion withy a substantially longitudinal cut ter abutment surface and a diagonally downwardly facing cutter expanding shoulder below that surface, the lower part of the abutment having a cutter abutment surface which makes van acute angle with the longitudinal, a cutter element movable both longitudinally and transversely in the body slot for expansion and contraction and adapted in expanded position to seat inwardly against both abutment surfaces, the cutter element having near its upper end a substantially vertical bearing face and near its lower end a bearing face that makes an acute angle with the vertical, and means for moving the cutter element upwardly relative to the body and abutment.

21. In an expansive reamer, a vertically extending body rotatable about a vertical axis, vertically extending cutters mounted in the body for movement vertically thereof, bearing means at the lower ends of the cutters holding the lower ends of the cutters against movement outwardly from the axis during upward vertical movement of said cutters, bearing means in the body lying be tween and forming an internal abutment for the upper ends of the cutters and guiding the upper ends in movements upwardly and outwardly from the axis, and actuating means carried by the body and acting to move the cutters upwardly.

22. In an expansive reamer, a vertically extending body rotatable about a vertical axis, vertically extending cutters mounted in the body, bearing means at the lower ends of the cutters guiding the lower ends in vertical axial movement in the body, bearing means in the body lying between and forming an internal abutment for the upper ends of the cutters and guiding the upper ends in movements upwardly and outwardly from the axis, and actuating spring means acting on the lower ends of the cutters and tending to move them upwardly.

23. In an expansive well reamer, a body and a tilting cutter therein, the cutter including a non-rotating carrier and a rotat'- ing cutter, means to cause tilting of the cutter to a position where a part of the carrier is projected further than other parts, and a removable wear member with a smooth casing engaging face mounted on said part of the carrier.

24. In an expansive well reamer, a body and a tilting cutter therein, the cutter including a carrier and a cutting element' cariid 'Bil

red thereby, means to cause tltngof the cutter to a position Where a part of the can rer s projected further than other parte, and a removable weer member with a Smooth casing engaging face mounted on seid party of the carrier.

In Witness that I claim the foregoing I have hereunto subscribed my name this 4:

day of February, 1928. I

JOHN GRANT.

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