US982514A - Underreamer. - Google Patents

Description

P. H. MACK.

. UNDBRREAMBR.

APPLICATION FILED DEO.11 1909. 982,5 1 4.

Patented Jan. 24, 1911.

2 SHEETS-SHEET 2.

l fri-5 UNITED STATES OFFICE. f

PATRICKVH. MACK, OF BRADFORD, PENNSYLVANIA, ASSIGNOR T0 OIL WELL SUPPLY COMPANY, OF PITTSBURG, PENNSYLVANIA, A CORPORATION 0F PENNSYLVANIA.

UNDERREAMER.

Specification of Letters Patent.

Patentedl Jan. 24, 1911.

Application led December 11, 1909. Serial No, 552,621.

Toall whom it may concern:

reamers; and I do hereby declare the following to be a full, clear, and exact description of the invent-ion, such as will enable others skilled in the art to which it appertains to make vand use the same.

This invention relates to the construction of that class of devices commonly termed underreamers, employed for enlarging the borers of oil or Artesian wells ,where casing is inserted.' In drilling with this class of tools the tool is inserted and withdrawn through the casing, and therefore the underreamer must be collapsible so that the extreme diameter of the cutting portion of the tool may be reduced at the time the tool is passed throu h thelcasing.

The prevai ing types of underreamers are those wherein a sliding connection between the stock and bits is effected either by means of dovetailed ways or re uivalent interlocking parts, or by means o an axial socket in theV stock for .the reception of the tangs of the bits, and in both of said types an interv posed spring or equivalent resilient means 1s employed for maintaining the bits in a normally expanded or operative position.

My presen? invention relates more especially to thatltype of underreamcrs wherein the stock and'bits are slidingly connected by means of interlocking parts, and has for its object such a formation and combination of the coacting parts as'shall provide for the reducibility of the diameter of the underreamer at its cutting portion, without complicating gr weakening the structure, and which will also provide for taking up any lost motion which may arise from the wear or upsetting of the coacting arts.

To this end', in that class o underreamers wherein are combined a bit-stock having av distance block for supporting the bits in their projected or operative position, and bits longitudinally movable on the stock, I form the recesses in the stock for the reception of the bit-'tangs with laterahwalls inclined to each other both outwardly and upwardly, and the bit tangs I form with lateral walls whiclrcorrespondingly converge both outwardly and upwardly, whereby the initial downward movement of the bits results in such clearance between the stock and y bits as will not only permit the tool to free itself of any accumulated fine sand or silt, but which will also permit of a tilting movement of the bit, while the wedging of they tang when the tool is being operated takes up any lost motion and obviates any tendency ofthe bit to tilt, and such'a construction embodies the main feature of my invention.

There are other, minor, features of invention embracing particular combinations and features of elemental construction, all as will hereinafter more fully appear..

In the drawings chosen for the purpose of illustrating my invention, the scope whereof is pointed out in the claims, Figure 1 is a'view in elevation of an underreamer embodying my invention. Fig. 2 is a similar View taken at right angles to Fig. 1. Fig. 3 is a longitudinal central section-taken 1n the plane of the line 3-3, Fig. 2, the bits being in the expanded or operative position. Fig. 4 is a longitudinal central section similar to Fig. 3, the bits being inthe collapsed osition. Fig. 5 is a transverse section taken 1n the plane of the line 55, Fig. 3. Fig. 6 is a transverse section taken in the plane of the line 6--6, Fig. `4. Fig. 7 is a detailed view in elevation of the lower'end of the stock, showing the tang recess of the stock adjacent to the ydistance block and abutments of the stock. Fig. 8 is a transverse -section of the underreamer taken in the plane of the line 8--8, Fig. 4, showing, as applied thereto, a clamp device for confining the collapsed bits when introducing the underreamer into the casing. Fig. 9 is a lonjgitudinal section of the lower end of the stock and bits taken in the plane of the line 9 9, Fig. 8, and Fig. 10 is a view in elevation of the underreamer showing the application thereto of a tool for collapsing the underreamer for introducing it into the casing.

Like symbols refer toilike parts whereverthe underreamer and B, B the bitsor cutters thereof. The stock A is provided at its upper end withthe usual pin p for attachment to the sub ordinarily interposed between the underreamer and the drill rod and with the wrench seat 'w for the reception of the wrench used in attaching and detaching the -underreamer from the sub and drill rod.

At its lower end, and on opposite sides of 4the intermediate portion of the stock, are

upwardly and inwardly inclined abutments a for engaging the shoulders on the bits B, B. Between the abutments a a atthe lower end of the stock, and integral therevthe reception of the spring which actuates the bits B, B. The spring chamber a? is threaded at itsl lower end, in the distanceblock, and is closed by a screw-plug ,P to retain the -actuating spring in position in the axial spring chamberv a2.

The stock A, on diametrically opposite sides of the spring chamber a2, is provided with bit recesses a3, or recesses for the reception of the tangs b' ofthe bits B. They lateral walls of the recesses a3 of the bitstock converge, or are inclined, to each other both outwardly and upwardly, or in otherv Words, therecesses are dovetailed` in cross.

section, taper longitudinally of the stock for a distance corresponding to the length of the bit tangs, and are of uniform depth throughout their length. Said bit recesses a3 communicate at their upper ends, or are connected -by a transverse slot through which passes the ke C which supports the two Y bits B, B, an causes them to move in unison under the influence of the spring D.. The clearance between. the stock and bits which permits the escape of fine sand and silt, as well as permits of the tilting of the bits when collapsed, is effected by the downward movement of the. bits. At the lower end of the bit recesses a3 there is a slight increase in the width of the distance block as at a4 (see Figs. 7 and 8) to accommodate the screw plug closure P of the borepor axial spring chamber a2, and on either side of said portion of the distance-block the clearance between the bits and the stock may be increased by slightly tapering the distanceblock asv at a. y f

B, B indicate the cutters or bits which are formed with tangs b, and with upwardly and inwardly inclined shoulders b that engage the abutments a on the the stock A.

The lateral walls of the bit-tang b converge, or incline to each other, both upthe stock is Y lower end of wardly and outwardly, that is to say, the

bit tang is of dovetail cross-section and cessing'of the inner faces of the tangs b results in the production of the projections b3 `on the inner faces'of the bits which projections engage the sides of the distance-block a when the bits are raised into their operative position by the action of the spring as indicated in Fig. 3 ofthe drawings. The

tangs b of the bits are provided at their upper ends with key slots b4 for the reception of a key C which key passes through a transverse slot a6 in the stock and su ports the two bits B, It is through this key as anintermediary that the bits' are actuated by the spring. The relative sizeof the key slots b4 and the key C should be such as will not interfere with the tilting of the bits in their sliding movement to and from their operative position on the stock A. The key C has a sllght notch or recess c in its under edge for the reception of the disk of a spring cap carried by the upper end of the actuatlng spring.

D indicates the spring for actuating the bits B, B, ythat is to say, for raising the bits from their lower or collapsed positlon (Fig. 4) to their normal or operative position (Fig. 3) and maintaining them in thedatter position. This spring is located in the bore or axial spring chamber a2 of the stock A between the bits and below the key C which connects the bits, and is provided at its upper end with a spring cap 0l which engages in the notch or recess c in the under edge of the key C. This engagement of the spring cap d in the notch or recess c of the key prevents the endwise displacement of the key, and the spring cap d is preferably forked on its upper face so as to straddle the key. The lower end of the spring D has its bearing on the screw plug P which closes the lower end of the bore or spring chamber a2.

The longitudinal taper of the tang of the bit and the corresponding tang recess of the stock is preferably, though ,not essentially, a uniform taper, not only because such a taper is more readily produced but because it is more effective in counteracting the effects of wear-and lost motion.

The elemental construction of the stockr A and bits B, B being of substantially the character hereinbefore noted,` the elements are easily and readily assembled by slidlng the tangs b of the bits into the tang recesses a of ythe stock froml below, passing essaim.

'is desired to pass the underreamer into 'and through a casing for drilling purposes, the

bits are drawn down into the collapsed position shown in Fig.'4 of the drawing. This may be done in any suitable manner, but I prefer to use a device such as shown applied to an underreamer inFig. 10 of the drawing, in which` L indicates `a lever having a forked end Zadapted'to engage the wrenchseat fw of the underreamer stock A, and a pivoted brace member Z provided with a toe l2 adapted to enter a suitable openin in the bit B. When the lever L is applic to the underreamer as shown in Fig. 10 of the drawing, the lever L ma be operated to force down the brace mem r l and withit the bit B until the spring is compressed and the bits forced into the collapsed position.

The bits can then be entered in the casing, or can be confined by a clamp as desired.

For this purpose any suitable means of hold-py sed position may be ing the bits in the colla employed. In Fig. 8 o the drawing I have shown a semi-circular yoke Y provided at one end with a clamp screw :n and this is employed y a plying one end of the yoke to one bit a d'tlhe other to the opposite bit and then tightening up the clamp screw When the underreamer is in the collapsed condition shown in Fig. 4 of the drawings the bits are inserted in the end of the casing and the clam Yx removed. The casing will confine the blts and maintain the under-` reamer in the collapsed position shown in Fig. Iet until the bits pass from the lower end of the casing, whereupon the expansion of the spring D which 'was compressed by the drawing down and forcing inwardly of the bits, will lift the bits into the normal and operative position shown in Fig. 3 of the drawing.- As a result of the longitudinal taper of the bit tang and tang recessl of the stock, the initial downward movement of theV bits with relation to the stock produces such a clearance of the parts as will permit of the tilting of the bits required for their inward or collapsing movement. This also reduces the friction and the consequent load i on the actuating spring in the reverse movement of the bits. Furthermore, the final uppward movement of the bits on the stock will eliminate all lost motion from wear or upsetting of the'parts, counteract any tendency of the bits to tilt land thus properly and effectively support the bits during the cutting operations thereof. The underreamer will be drawn into and through the casing in the usual way, that is to say, the upward pull on the underreamer' will bring the outer surfaces of the bits into engagement with the lower end of the casing which will hold the bits until the continued upward movement of thestock compresses the actuating spring' and the recesses b2 of the bit tangs are opposite the distance block ai of thel stock, whereupon the bits will move inward, or collapse, so that they can pass intoand through the casing. i

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

v1. In an underreamer, the combination'l bit recesses the lateral.

with a stock havin walls of'wliich are inclined to each other, of

bits longitudinally movable on the stock into and out of operative position said bits rovided with tangs having lateral walls w ich are inclined to each other.

2. In an underreamer, the combination with a stock having bit recesses'the lateral walls of which are inclined to each bther upwardly, of bits longitudinally movable on the stock into and out of operative position,

said bits provided with tangs having lateral walls which are inclined to each other Iupwardl y 3. n an underreamer, the combination with a stock having bit recesses the lateral walls of which are inclined to each other both upwardly andl outwardly, of bits longitudinally movable on the stockinto and out of operative position, said bits rovided with tangs having lateral walls w ich are inclined to each other "both upwardly and outwardly.

4. In an underreamer, the combination of a stock havin a distance block which supports the bits 1n operative position and-provided with bit recesses the latera ywalls ci which are'inclined to'each other, of bits longitudinally movable on the stock into and out of operative position, said bits provided with tangs having lateral walls which are inclined to each other.

5. In an underreamer, the combination of a stock having a distance block which supports the bits inoperative position and provided with bit recesses the lateral walls of which incline to` each other u wardly, of.

bits longitudinally movable on t e stock into and out of operative position, said bits pro,-

.vided with tangs having lateral walls which incline to each other upwardly.

6. In an underreamer, the combination with a stock having a distance block whichv supports the bits inoperative position, and

able on the stock into and out of operative position, said bits provided with tangs havj ative position..

ing lateral walls which incline to eachother both upwardly and outwardly.

7 Inan underreamer, the combination with a stock having a distance block at its lower end which supports the bits in operative position, lateral abutmentsforthe bits,

- and bit recesses the lateral walls of which ining bit recesses the lateral Walls of which converge upwardly and outwardly sald recesses adapted to permit the movement of reamer bits longitudinally of the stock.

10. An underreamer bit having shoulders,

and a tang the later-alwalls of which converge in two directions.

l1. An underreamer stock having at the lower end and opposite sidesl thereof longitudinally extending bit recesses for the reception of bit-tangs, said recesses having lat- -eral walls inclined to each other both out wardly and upwardly said recesses adapted to permit the movement of reamer bits 1011-.

gitudinally of the stock I,and said recesses communicating at their upper end.

In testimony whereof I aix my signature,

in presence of two subscribing witnesses.

PATRICK H. MACK. i Witnesses:

G. P. EINER, HUGH M. STERLING.

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