US1478306A - Underreamer - Google Patents

Description

Patented Dec., )18, i923.

untranstares iniciar-mr. nr. swnn'rntan, or Kansas Grrr, MISSOURI.

UNDERBEAMER Application led Octoberl 1B, 1920. Serial No. 417,573.-

Toall lwhom, it may concern:

Be it known that l, MICHAEL M. SWEET- MAN, a citizen of the United States, residing at Kansas City, in the county of Jackson o and State of Missouri, have invented certain new and useful Improvements in Underreamers, of which the following is, a

specilication. ,y y

rThis invention pertains to underreamers l@ tor well drilling, and the structure is designed or use more particularly with deep wells'wliere the soil is 'such that diliiculty inheresfin' cementing the casing in its linal position. Various structures have heretol@ fore been devisedand patented for underreaming, but difficulty obtains in the operation of such tools where a rotary. drill rod has to be employed, for instance, in deep wells of Texas. 2@ be made to properly perform its function and produce a chamber at the lower portion of the well into which the cement may flow, the wells may blow out.

rl`he structure which forms the basis of `the present invention is illustrated in the accompanying drawings wherein,-

Fig. 1 is a vertical vlongitudinal section of the underreamer -with thecutters shown in their extended operative position; an

Fig.y 2 a horizontal sectional view taken on the line llt-ll of Fig. 1.

ln the-drawing, 1 denotes the. mandrel or stock of the tool having a box' 2 formed at its upper .end and a pin 3 at its lower end. Opening from the lower portion `of the threaded box 2 is a cylinder a in which is mounted a piston 5. Said piston has attached to it a piston rod 6, the lowerend of which is fashioned intoa double-face rack 7 or the rack may be formed as a separate elementV and attached to the rod. The piston rod 6 passes chamber or bore 4 which is a virtual continuation o the cylinder It. A spring 8 resting at its lower end upon an inwardly projecting shoulder 9 and chamber It, contacts the under face of the piston and tends to elevatel said piston and consequently to `raise the piston rod and the rack element. By-pass ports l() are formed in the side wall of the lower portion of the cylinder t so that when the piston is in theposition shown in Fig. l the water which is forced downwardly through the drill rod or tube will pass through said ports Unless the underreamer canV .which they I derreaming operation downwardly through a y housed within the.

below the iston and into the chamber 4, thence finding its way outwardly around the various elements, such Vas the cutters or bits 11 and 12. Said bits may be of any approved type. Each bit (the bits being duplicates) is mounted upon a pin 13 which extends through the body of the stock or mandrel 1. Said mandrel is provided with oppositely disposed slots 14. extending through the" body thereof and in which slots the bits are 'mounted Each bit is provided with a circular rack, as 15, which cooperates with the adjacent rack element of the member 7, so yl that as the rack is moved downwardly into the position shown in Fig. 1 the bits will be swung outwardly and as the rack is moved upwardly the bits will be rocked and swung downwardly passing into the slots 14 by are housed.

lin operation a fish-tail cutter may be mounted uponthe pin 3 in order to drill an extension of the hole, or if the hole is of sufficient depth, a suitable guide member of any form may be secured upon the'pin. rThis arrangement acts to center and guide the tool. `When itis desired to eliect the unthe tool isplaced upon the lower end of the drill stem and lowered d to position. lWhen it reaches' a point where the bits or4 cutter blades 11 and 12 may be lprojected outwardly to begin -the cutting operation, water under presseure is forced downwardlyl through the stem and into the cylinder 4. 'l he pressure will force the piston 5 downwardly, placing the spring under compression and forcing the bits ultimately outwardly .and into. the position shown'in Figl. Then through the manipulation of the drill stem the blades will be carried around and the undercut or reamed out chamber, as 16, produced. This Chamber desired vdepth and of any desired diameter, the latter being dependent solely upon the length of the bits. The'pressure of the water is such that the piston will be held in its downward position so that the water willtravel downwardly through the by-pass chamber 4a, around the piston rod 6, and outwardly through the slots 14, commingling with the soil which is loosened by the bits. Such mixture of water and soil, or, in effect, the'1nud,will be carried upwardly through the well casing, denoted by 17, and discharged as usual. Then the undermay'be made of any Seo not

ports 10, through the .reamed opening or chamber has been made of suilcient size the Water supply will be cut 0H, whereupon the/spring 8 will exert an upward pressure to raise the piston and its attachedparts and the rack will tend to swing the bits inwardly into. the slots or openings 14. As the mandrel is drawn up- Wardly, and in the event tliejbits should i sticky they Will contact the lower end of the casing 17 and be forced downwardly into their closed position thereb the curvature b ot' the back ,6 of the.,bits assisting in this action. l

YWhat is claimed is :1.,-

Lian underreamer, the combination of a mandrel provided with a cylinder in its upper portion and with Y( disposed slots formed inthe side wall therea pair vof oppositely drel' to permit passage of water below the piston and outwardlyithrough the/body of the mandrel when the piston is forced downwardly by the Water pressure; abit pivotally mounted in each of the slots aforesaid; a

gear formed upon each of said bits a, double face rack cooperating with the gears of the its; a piston rodN extending from the rack and connected to the piston; and a spring located beneath the piston and servingto elevate the same when the Water pressure is i Withdrawn therefrom. y

lin testimony whereof li have signed my name to this specification. Y

- `MIUCITIAEL M. SWEETMAN.

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