US1740829A - Underreamer - Google Patents

Description

Dec. 24, 1929. w B NlCHOLS 1,740,829-

UNDER BEAMER Filed Jan. 4, 1928.

7 ZIJ f 24 Z Patented Dec. 24, 1929 WILLIAM B. NICHOLS, OF GRAHAM, TEXAS UNDERREAMER Application filed January 4, 1928.

This invention relates to improvements in under-reamers and more particularly to that type of under-reamers which is employed in drilling oil wells.

One of the objects of the present invention is t provide an under-reamer so constructed that it may be more readily `inserted through the well pipe, preparatory to operation, than under-reamers of the ordinary construction, and in this connection the invention conten plates so mounting the cutters of the underreamer that the same may be retracted and held in retracted vposition while the underreamer is partly inserted into the Well pipe, and the cutters then released to be automatically expanded to working position,A upon downward movementof the under-reamer in the Well pipe to a position to extend below the lower end of said pipe.

Another object of the invention is to provide an under-reamer so constructed that the cutters thereof may be readily removed and other cutters substituted therefor, so that cutters of different sizes may be employed and 25 therefore the single tool may be adapted to cut bores ofdierent diameters, in the oil bearing rock.

Another object of the invention is to provide an under-reamer so constructed that, on the up stroke of the tool, the cutters will be relieved of strain, at the beginning of said stroke, thus obviating any likelihood of the cutters being torn loose from the tool.

`While the accompanying drawings and the description which is to follow, constitute a disclosure of the preferred embodiment of the invention, it will be understood that various changes may be made within the scope of what is claimed.

In the accompanying drawings:

Figure l is a view in side elevation of an under-reamer constructed in accordance with the present invention;

Figure 2 is a vertical longitudinal sectional view taken substantially on the line 22 of Figure 1 looking in the direction indicated by the arrows;

Figure 3 is a bottom plan view of the underremuer;

Figure a is a horizontal sectanal view taken Serial No. 244,461.

substantially on the line 4:4 of Figure 2 looking in the direction indicated by the arrows;

Figure 5 is a perspective view of one of the cutters of the under-reamer;

Figure 6 is a View similar to Figure 2 illus- 55 trating a means which may be employed in retracting the cutters at the time of introducing the under-reamer into the well pipe.

The under-reamer embodying the invention comprises a cylindrical body shell l which is exteriorly ot a diameter nearly equal to the internal diameter of the well pipe through which the under-reamer is to be lowered to working position, and this shell is interiorly threaded near its upper end as indicated by the numeral 2 and houses a tubular barrel which is indicated by the numeral 3 and which is exteriorly threaded for a portion of its length as at 4L to adapt it to be threaded into the shell l. The barrel 8 is provided with a bore indicated by the numeral 5 the lower portion of which is of increased diameter as indicated by the numeral 6, for a purpose to be presently explained, and the barrel is provided at its lower end, exteriorly, with a circumscribing flange 7 which abuts against the lower end of the shell body l and which, for a vpurpose to be presently explained, is provided, at intervals in its circumference, with notches indicated by the numeral 8.

The under-reamer further embodies a plunger including a. stem 9 which is slidably iitted in the bore 5 of the barrel 3 and the lower portion of which is threaded as indicated by the numeral 10 and has adjustably fitted thereto a nut ll provided in its under face with diametrically oppositely located notches l2 for the application of a spanner wrench whereby the nut may be adjusted upon the stem. A compression spring 13 is arranged upon the stem 9 within the enlarged portion 6 of the bore 5 of the barrel 3 and bears at its upper end against the shoulder which is provided at the upper end of the enlargement 6 of the bore and, at its lower end,

vbears against the nut ll, it being understood that the tension of the spring may be varied by adjusting the nut l1 and that the stem 9 may have upward sliding movement in the here ef the barrel 3 against the tension of ien the said spring, the spring however normally holding the plunger 9 yieldably in a downwardly shitted position and with the head ot the plunger, which is indicated by the numeral 14, abutting against. the upper end of the said barrel 3. rIhe head 14 of the plunger is provided at its upper end with the Vusual conical threaded stud 15 i'or the Vconnection of the drill rod of the drilling apparatus, so

that reciprocatory motion. may be imparted to the under-reamer after the same has been lowered through the Well pipe and past :the lower end of said pipe.

The cutters of the under--reamer are indicatedin general by the numeral 16 and each 'compri'sesfaE body 171ha`vingf-a shanlr- 18 projecting from its'up-perside and Yformed `with Vanl opening19- to accommodateA a pivot pin 2O which is fitted therethrough and chordally throughlthe barrel-3,'near the lower end thereof,-and transversely otfone-oi1 a plurality of slots 21 which-'are provided in the said'. portion of; the barrel to laccommodate thesaid Shanks-18ct the cutters. The body I17 `of l-each cutter is ypreferably of segmental Vform anch-whenr` thel cutters are in the projectedpositionsfshownin Figures 1, 2 and Soi the drawings, the bodies project beyond the outer side of theshell 1 oi' the underreamer, in position to act upon the rock to be drilled, and in order that the4 cutters may be rein-iorceduwhen in' this position, the upper l's'ide"ot'each cutterfat opposite sides of the shank 18,*'is fiat-as indicated by the numeral 22 Vandfabuts squarely Vaga-inst the lower end of"the" barrel"{9i-Tand"the` under side of the flange,'7-at said end of the barrel, each oi' the cutters? beingforme'd--at its upper end and immediately outwardly of the shank 18, 'wi-th a1K lug-or `boss 23 which, in this lposition of the cutter, engages in the respective one ot 'the notches 8. Each cutter 16 is provided, at; the lowerouter side oii-its body 17, with a cutting lip 2ey having an arcuate, perpendicular outer-'face -25,and ai flat under face y26; these faces defining, `between them, a chipping' edge'?. Atthis point lit will be evident, and particularly by reference to Figure `6 fof 4the drawings, that the -pivotJ pins. 20 'for the cutters are :freely in-serted in openings provided for their reception, inthe barrel 3 lat the opposite sides ot the slotsinsaid barreland that therefore-the pins may bereadily removed, when the-barrel isremoved from the shell" 1. VTherefore cutters of idiiierent sizesmay -be substituted one for another and the under-reamer adapted to undercut holes of various diameters,` and'inthismanner the 'invention obviates `the employment ot anumber of' lseparate and distinct -under-reamers 'for this purpose.

From the foregoing description of the 1invention it will be'evident that, when the cutters are -forced inwardly; and-l an upward pull is exertedupon the plunger 9,. the cutting edges of the cutters may be brought to position within the circumference of the shell 1 and consequently readily inserted into the well pipe, and, when the under-reamer has been moved downwardly through the pipe and the lower end of the under-reamer eX- tends below the lower end of the pipe, the cut-ters willbe automatically proj ected'radially inan. outward direction to active position.

,Figure 6 of .the drawings illustrates a convenient meanswhereby the cutters may be Iretracted and temporarily held in such position, prior to insertion of the under-reamer A- intofthe .upper end of. the well pipe, and in this ligure the numeral 28 indicates hooks which are equal in number to the number of cutters, as for example, three,.andwhich are provided with overturned, .inwardly projecting bills 29 at their -upper'ends and with eyes 30 `aty their lower ends, the eyesY providing means whereby cords. 31.rnay` be connected with the shanlrs of' the hooks to exert a pull upon. the hooks, when their bills are engaged in -soclrets 32 which may vbe formed in the upper endsoi the bosses 23 'of Y.

the cutters. et this point it willbeevident that byV exerting a downward` pull upon all of the cords 31, after the hooks. have been engaged with the respective cutters, andholding the plunger 9 stationary, 'the same being attached -to the rod of the drill, the cutters may be caused to swing vinwardly to the position shown in Figure 6,Y and at` this time a cord 33 may bespassed about'the cutters and knotted so as' to retain the cutters in this position, temporarily, the hooks 28,:at this time, beingdisengaged from the cutters. yThe lower end of the under-reamer may then be inserted into the upper end or" the well pipe until the cutting edges 27, or thefaces 25;k

threaded portion 10, and which portionis' tapered as illustrated in the` drawings and indicated by they numeral 10', will wedge between the inner edges of theshanlrs 18 of the cutters, lwhich edges are, for this purpose, inclined, and cause outward swinging movement ot the cutters about their pivots 20, to activev position, the cutters being in this manner restrained aga-inst inwarddis- `placemenhon the down-stroke of the underreamer, but, on the up stroke, dueto the -momentary yretraction .of the plunger-stem 9, beingpermitted to Yswing inwardly -to clear the surface of the rock. Y

Having thus described the invention, what lI claim isi 1. An under-reamer comprising a barrel,

1a. plunger including a stem slidablyI mounted iso in the barrel, the stem having a threaded portion, a nut threaded onto the said Stein, a spring within the barrel bearing against the said nut and yieldably holding the Stem in a downwardly shifted position, the stem being provided with a head engaging the upper end of the barrel and limiting the downward movement oi the stem in the barrel, and cutters pivotally suspended from the lower portion of the barrel, the plunger stein having a tapered lower end portion for coaction with the inner sides of the cutters, upon downward movement ot the plunger, to Swing the cutters outwardly to active position.

2. An under-reamer comprising a barrel, a plunger including a stem slidably mounted in the barrel, cutters, pivotally suspended `from the lower portion of the barrel, the cutters having shoulders engaging against the lower end of the barrel, in the outwardly swung position of the cutters, the said stem having a tapered lower end portion for coaction with the inner sides of the cutters, upon downward movement of the plunger, to swing the cutters outwardly to active position, a spring coaeting with the plunger and yieldably holding the same in a downwardly shifted position eoacting with the cutters, the plunger Stem having a threaded portion, and an abutment adj ustably threaded on said portion and engaged by one end of the spring and constituting means whereby the tension of the spring may be varied.

3. An under-reamer comprising a barrel, the said barrel being provided in its lower portion with vertically extending slots opening through its lower end, cutters having shanks pivotally suspended in the upper ends of said slots, the inner Sides of the Shanks being inclined, a shell upon the barrel closing the outer sides of said slots, the outer sides of the cutter Shanks being engageable against the said shell in the outwardly swung position of the cutters, the cutters having shoulders engageable beneath the lower end of the barrel in the outwardly swung position of the cutters, and a plunger including a stem slidably mounted in the barrel and having a tapered lower end portion for coaction with the said inner sides of the cutter Shanks to eilect outward swinging of the cutters to active position upon downward movement of the plunger.

4. An under-reamer comprising a barrel, the said barrel being provided in its lower portion with vertically extending slots opening through its lower end, cutters having shanks pivotally suspended in the upper ends of said slots, the inner sides of the Shanks being inclined, a shell upon the barrel closing the outer sides of said slots, the outer sides of the cutter Shanks being engageable against the said shell in the outwardly swung position of the cutters, the cutters having shoulders engageable beneath the lower end of the barrel in the outwardly swung position of the cutters, and a plunger including a stem Slidably mounted in the barrel and having a tapered lower end portion for coaction with the said inner sides of the cutter shanks to effect outward swinging of the cutters to active position upon downward movement of the plunger, the plunger having a head upon its stem for coaction with the upper end of the barrel in the downward. movement of the plunger.

5. An under-reamer comprising a barrel, the said barrel being provided in its lower portion with vertically extending slots opening through its lower end, cutters having shanks pivotally suspended in the upper ends of said slots, the inner sides of the Shanks being inclined, a shell upon the barrel closing the outer sides of said slots, the outer sides of the cut-ter shanks being engageable against the said shell in the outwardly swung position of the cutters, the cutters having shoulders engageable beneath the lower end of the barrel in the outwardly swung position of the cutters, a plunger including a stem slidably mounted in the barrel and having tapered lower end portion for coaction with the said inner sides of the cutter Shanks to effect outward swinging of the cutters to aotive position upon downward movement of the plungcr, the plunger having a head upon its stem for coaction with the upper end of the barrel in the downward movement of the plunger, a portion of the stem of the plunger being threaded, an abutment element adjustably threaded upon said portion of the Stem, and a compression spring within the barrel bearing at its lower end against said abutment element and yieldably holding the plunger in a downward direction.

6. An under-reamer comprising a barrel having slots in its lower end portion, cutters having Shanks disposed within said slots, the walls of the slots having openings the outer ends of which open through the outer sur- :tace of the plunger, the Shanks of the cutters having openings registering with the openings in the walls of the respective Slots, pivot pins removably tted through said openings and removably retaining the cutter Shanks in the slots, and a plunger including a stem slidably mounted in the barrel and having' a tapered lower end portion for coaction with the inner sides of the cutter Shanks, in the downward movement of the plunger, to effect outward swinging of the cutters to active position.

In testimony whereof I aiiix my signature.

WILLIAM B. NICHOLS.

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