US1522891A - Drilling bit - Google Patents

Description

George J5. Larbqcic 2 Sheets-Sheet l Filed Feb, ll, 1924 G. B.. LOUDERBACK Ma/wey.

,1m 1s, 19125.r

Jan, i3, 1925.

G. a. .-LQUDERBACK DRILLING BIT Filed Feb. ll, 1924 Patented Jan. 13, V1925.

GEORGE B. LOUDERBACK, OF.C`0MPTON, CALIFORNIA.

DRILJTNG Brr.

Application led February 11 1924. Serial No.-691,998.

To all whom t maj] concern:

Be it known that I, Geenen B. LoenennACK, a citizen of the United-v States, residing at Compton, in* the county of Los Angeles and' State of California, have invented a new and useful Drilling Bit, of which a specification is set forth below.

In this specification, and the accompanying drawing, I shall describe and show a preferred form of my invention, and specifically mention certain of its more important' objects. I do not limit myself to the forms disclosed, since various changes and adaptations may b e made therein without departing from the essence of my invent-ion as here inafter claimed; and objects and advantages, other than those specifically mentioned, are included within its scope.

My invention relates to well .drilling bits for usev with rotary rigs. Its principal objects include; first, to provide a tool ot this character having extensible cutting blades adapted'for being periodically advanced as they become worn, without removing the bit from the drill hole; second, to afford facilities for advancingthe cutting blades, while unde'y ground, .in such a manner that the gauge of. the drill hole may constantly be maintained. or even enlarged; and, third, to accomplish the above objects by means of a relatively simple construction that may be depended upon to function as intended.

'lhese objects are accomplished by means ot the construction illustrated in the accompanying drawings, in 'which-- Figure 1 is alongitudinal axial section of the upper portion of the tool in elevation;

Figure 2 is a similar section of the lower portion of the tool, taken on the same plane as Fig. 1;'

- Figure B'is a longitudinal axial section of the upper portion of the tool taken on a plane revolved 90 degrees from that of the first two figures;

y Figure 4 is a similar section of the-lower portion of the tool. taken on the same planeas Fig. El;

Figure 5 is a much enlarged perspective view of an upper portion of the operating mechanism);

Figure 6 is an enlarged axial section of l. the lower portion of the operating mechanism, taken on' the same plane as Fig. 3, an

Figures 7, 8, 9, and 10 respectiuelysaie 55 cross sections taken on the lines T--'T 8-8, 9 9, and lO-lO of Figs. 1 and 2'.

Similar reference numerals refer to siinilar parts throughout the several views.

In a general way my improved tool `is 60 adaptedA to operate in the manner of the ordinary fish-tail bit employed in rotary drilling, there being a pair of cuttingblade'lsn 1n substantially the same plane, extending oppositely from the axis. 1 The leading bot- B6 .tom edges of these blades do the cutting. In all such tools the Wear on the cutting edgestends to become greater as the distance from the axis increases, due to the greater cutting speed and the greater amount of ma- 'I0 terial encountered. In addition to this the tips have the additional duty of maintaining the gauge of the drill hole and have to withstand the abrasion caused by the unavoidable wobbling of the tool. In consequence of this the tips of ordinary bits soon become rounded and blunt, and the tool is thereby rendered unfit for further servico until it has been withdrawn from the drill hole and redresscd. A so Obviously, in the case of deep wellsparticularly, the time lost in the repeated fwith drawals and re-placement of ordinary. bits is often a matter of grave concern. Moreover, as the tips oi the cutting edges of such bits become rounded by Wear, the drill Ahole loses its gauge and becomes smaller. Consequently, when a redress'ed tool of standard gauge is substituted,it' has to perform a reamin'g operation before the bottom of the 90 hole is reached. This roaming duty comes entirely upon the tips of the blades and in a large measure destroys their cutting elliciency before .the depth drilling` can be resumed.

In a previous application-for patent, filed January 16, 1924, Serial #686,569, I disclosed a novel type and arrangement of cutting blades, and means for a vancing them from the lovier end o'f the tool obliquely to l0 the axis. Entirely vsimilar blades and' blade arrangement are employed in the tool to be described, but are not claimed herein per sc.

The means employed for advancing the blades in the present case are, however, quite distinctive and constitute the present invention.

The adjustable cutting blades 11 and l2 are bifurcated and provided with a flange 13 on their leading faces at each side of their bifurcations. A thicker {lange 14 is provided at the leading side of their outer edges. lt now possible to make these ftanges, as wc'll as the whole leading faces ot' the blades, -very hard in comparison to the main body of metal. The cutting edges therefore ha've a greater' wearresisting quality and, tor that. reason, the blades have a marked self-sharpening tendency. This tendency is further enhanced by the fact that the blades are relatively very thin. but strength is not sacriiced since they are backed up and supported,

close to their cutting edges, by the heavy metal of the tool body. The localized thickening of the blades by the flanges'. where the greatest tendency to wear occurs. `tends to make the wear on the cuttingr edges more uniform and thus to prolong their effective drilling life.

Thisability to advance the cutting blades obliquely to the axis, provided .the Acutting edges have not been destroyed. makes the tool very largely independent of the shape to which 'the blades may wear. Thus. in the event that tlre points of thel blades become rounded, the gauge of the drill holecan be maintained by advancing the blades, and thc tool will continue to cut asetectively as it. did before the rounding occurred.

It will occur to some that', as the blades are obliquely advanced from the end of the tool, the cutting edges will recede from the center; and that, in the form depicted. there are in fact no cutting edges at the center of the tool. It isr conceivable that in cert-aiu -formations, with a perfectly centered rcvolving tool, this disposition of the cutting edges might tend to leave a central core that `would interfere with the drilling. ln practice, however, this never occurs. The tool never revolves truly about a fixed axis, and the unavoidable wobblingv prevents the formation of such a core, since -it would be quickly cut into and destroyed if it occurred. Furthermore, the weight of the tool string, which Ais'very heavy, could not be supported by a core'of this kind. lt. would quickly' crumble under such a load. For those reasons no trouble. from cores is ever experienced in drilling operations of -this character.

The body of my bit is made in semi-cylim drical halves 15'and 16. of identical shape. with accurately machined or ground faces.l These are cast or forged with variousl refcesses'such as 17, for theaccommodation of the working parts they are to enclose, and

are assembled face to face my means of ar threaded ring 18 at the top, and a wedge band 19 at the lower end.' The lower portion of thebody 'is slightly wedge-shaped, as indicated in Fig. 4, and isa modified ellipse in section, as shown in Fig. 10. This portion becomes increasingly elon ated in cross section towards the lower en of the tool. W'edge band 19 is driven from the bottom on to a slightly tapered seat against a shoulder at 20. Bolts 21, passing through thc bifurcations of the cutting blades, af-

ford still further security against displace-Y nient o f the body halves.

The central portion of the tool body is' threaded at22 and a tubular housing 23 is screwed upon it at that point. This housing is somewhat enlarged at its upper end and a tubular member 24 is screwed into the top. Member 24 carrieslan integral taper-threaded pin 25 at its upper extremity, forengagement by the tool joints of -the tool string.`

The mechanism by which the cutting blades are held and controlled is mostly enclosed within housing 23 and the halves of the .tool body. It comprises a relatively long feed screw 26 engaged by a cylindrical flanged nut 27. The screw itself does not turn. It is lowered by turning its feed nut, which may be revolved but is longitudinall positioned by means of its flanges 28 whicv engage corresponding grooves in the body parts.

At the lower end of the feed screw is a flattened blade retainer 29 having a, transversegroove 30 across each of its faces adjacent to the bttom edge. The two cutting blades are similarly grooved to form flanges attheir top ends, the end flanges of the -blades being adapted to fit into the grooves of the retainer and vice versa. The cuttingl at all times by mea-ns of oblique grooves inY the body in which liangcs13 and 14 of the blades are slidingly engaged. This isclelar yly illustrated in Fig. 10 and indicatedby `dotted lines in Fig. 2.

As the blades are fed obliquely l l t) lil() Feed nut 27 is turned to lower the feed l,

screw by means of a ratchet clutch device."

This comprises an operating spool.].with

. comprise a pair .friction rollers ,power blocks 42 which are adapted to slide 'radially in and -quill and to 1. -through the key end of the quill is smooth-bored to permit vthe operating screw it.- and is provided a smooth bore, through which the feed screw passes. The adjacent end faces of the feed uut and operating spool have radial ratchet teeth 32, i lapted for mutual engagement.

Operating spool Ill has a multiple thread 33 on. its outer surface adapted to engage a toothed nut l-L. Beneath this nut isv a light helical spring supported at the bottom by a ball thrust bearing-36L The upper portion of the operating spool is provided with a longitudinal key-'way 3T A and 1s surrounded by the tubular end of the- 'lhis quill has an internal 2li), engaging key-way 3.7 1n the operating spool, and

the latter' is adapted to slide longitudinally within the be rotated by it in any position, and key-way. The upper driving quill 38. longitudinal key to pass freely through with peripheral teeth 40 whereby it may be driven.

In order to operate the feed mechanism just described friction drive devices are located in the upper end of housing 23. These 'of' dirmetrically opposed 41 rotatably mounted in out of rectangular orifices cut for that purpose in the enlarged upper end of housing 23. The power blocks 'are normally separated. by compression springs 43, so as to re-act against each other and to force their respective friction rollers into contact with the internal walls of the well casing. Revolving 'the tool will then cause the rollers to revolve` about their individual axes and furnish a source of power for operating the feed mechanism.

Reduction gearing, indicated at 44- is located Within each of the power blocks and the power taken from th`e rollers is communicated to drive shafts'45 through `telescopic joints 46 and universal couplings 4T. At the lower endsv'of, drive shafts 45 are pinions 48 meshing 'with teeth ttl-of the driving quill.

lontrol of the feeding mechanism is accomplished through' an offset plunger rod 49 at each side ot. the cutting blades. These are adaptedto slide longitudinally in slots in the. tool body, and extend from the bot# tom of the tool nearly to its top. -Attheir upper ends the plunger rods are connected b v a yoke bar 50 and they are normally pressed downward and outward from the end of the tool. by a compression spring 5l rc-acting against this yoke,4 At their lower ends the plunger rods are fixed to an operating Shoe 52.

42 are provided with upwardly pointing wedge shaped grooves 53 inpeach of their lateral faces. Corresponding wedge shaped flanges 54 areprovided lin a pair of sliding cams 55 fixed at the Power blocks proper points to the respective' plunger rods. F langes 54. are adapted to engage grooves 53 to force the power blocks together' When the rams are raised by the plunger rods. ln this manner. when the weight of the tool is allowed to rest upon shoe 52, the plunger rods and rams arc pushed upward and bring the power blocks together. Conversely when the weight of the tool is taken off shoe 52 the rods and cams are pushed downward by spring 5l and the power blocks are forced outward by springs 43 untilthe friction rollers are in contact with the well casing. Rotating the tool in this position will then operate the feed mechanism to advance the cutting blades from its lower end.

I have provided in my improved bit a means whereby number of turns may feed nut in the manner ]ust eration ot the feet described. Op-

a definitely pre-determinedbe imparted to the -driving 'mechanism beyond this point will cause ratchet teeth`32 mechanism has already been described in part. l'ts operation is as follows: On plunger rods 49 are splines to engage the teeth of nut 34 to prevent its being turned.- This engagement takes place as soon as the weight of the tool is taken otf the operating shoe a'nd the plunger rods are pressed downward by spring' 51. The feeding mechanism =is then in position to operate as soon as poweris applied to it. and operating spool is turned to lower the -feed screw an nut. 34 is forced down Ward by the action llVhen nut 34 has traveled downward as far .as it can goby reason of its reaching stops 57, the further rotationof the operating spool will result in raising the latter and causing ratchet teeth. 32 to .become rl`isengagefl'."Tlie toothed nut. is restored 'to iis normal position b v reversing-thc rota-A tion of the tool while in its raised/[iosition.A Beneath feed nut '27 it is desirableto install a ball thrust bearingvl to reduce the frictional resistance of this nut when it is being turned. At that time the weight of the cutting blades is hung upon thefeed screw and is supported by this thrust bearing.

An important feature of my device remaining to be described is the manner in which circulating water is delivered in advance of the cutting edges of the blades. `Within the upper portions of the body halves circulating water grooves are pro# vided and are closed to form tight Water courses when the halves are assembled. A pair of smaller holes 59 are the bottom "of each half to communicate with the respective lower ends of these Water courses. lhese small holes 59 are located of multiple thread 33.v

drilled from 10, just forward 56 adapted of the cutting edges of the blades, and in a position to deliver the circulating' water most advantageously.

W'hen the body halves are assembled, pipes (30 are brazed, or otherwise tightly jointed, into the upper ends of the water circulating grooves inthe body parts', anda distributing box Gl. is mounted upon the upper ends of these pipes in the manner indica-ted in Figs. l and 3. vThis box has a central inletpip'e 62 adapted` to pass through an axial bore in pin 25, and be made tight therein by a stuffing box such as is indicat'ed 1n Fig. 3 at 63.

The construction and operation of the es'- sential elements of my invention `will be clearly understood from the foregoing description and drawings. Reaming lades Getmav be employed in the manner indicated if thought dcsirable,but ordinarily these will not he required, or will have very little duty to perform, on account of the ease with which the gauge ot the drill hole may be maintained by advancing thc cutting blades.- i

I wish to call particular attention to the fact that, although the circulating water passes through my device from end to end,

it is contained in a tightly closed course y throughout, and is nowhere permitted to come into contact with myn-of the working parts. The power blocks may be`\packe by felt strips where they move into and out of the tubular housing, and the latter may be packed with heavy grease as a further insurance of keeping out` mud and water. The more delicate of the working parts are tightly enclosed in the power blocks and body halves respectively, and may be constantly immersed in heavy oil or grease introduced through suitable plug holes for that purpose.

I claim as my invention:

l. A. drilling bit having cutting blades adapted tor being advanced obliquely to its axis and means adapted for actuation by frictional engagement with the walls of a drill hole for making said advancement.

2. A drilling bit having cutting blades adapted for being advanced obliquely to its axis and means comprising a feed nut for making said advancement; said means being operative through frictional engagement with the walls of a drill hole.

3. A drilling bit having cutting blades adapted for being advanced obliquely-to its axis and means comprising a non-rotatable feed screw with a rotatable thereon for making said advancemergaf'said means being operative throu h.-iction:1l engagement with the wallsfo a drill hole.

f'f drilling bit having cutting blades adapted for being advanced obliquely to its axis and means comprising a non-rotatable feed screw with a rotatable nut thereon for maki said Iadvancement.; said means being operative through frictional engagement with the walls of a drill hole and controlled by plunger rods normally projecting from the end ot said bit.

A drilling bit having cutting blades adapted for being advanced obliquely to its axis'and 'means comprising a rotatable feed nut for making. said advancement; said means being operative through `irictional engagement with the walls of a drill hole and adapted for automatic disengagement from said nut when the latter has made a pre-determined number of revolutions.

6. A drilling hit having cutting blades adapted for being advanced obliquelyto its axis and means comprising a rotatable feed means-being operative through trictional engagement. with the walls o'E-)a drill hole and adapted for automatic disengagement from said nut when the latter has made a pre-.determined number of revolutions; said hit having slidahle plunger rods normally projecting from its end whereby said means can be controlled.

7. In combination with a drilling bit having cuttingblades Lidapted for advancement obliquely to its axis; 1a rotatable feed nut adapted for causing said advancement; an disengageable means operative through fricd tional engagement with the walls ofa drill hole for rotating said nut. i

8. In combination with a drilling bit having cutting blades adapted for advancement obliquely to its axis: a rotatable feed nut adapted for causing said advancement; and disengageable means operative through frictional engagement with the walls ot a drill =hole for rotating said .nut a pre-determine number of revolutions.

9. 'In combination with a drilling bit having cutting blades adapted for advancement ohliquely to its axis; a rotatable fred nut adapted for causing said advancement: and means operative through frictioual' engagement with the walls of a drill hole for rotating said nut and automatically disengaging' therefrom when said nut hits-made a predetermined number (Ltrevlutions.

10. In combipatlf'n with a drilling hit having cutting blades adapted for advancementfo'liquelv to its axis: a rotatable feed :mit adapted for causing said advancement; and means for rotating said nut a pre-determined number vot revolutions comprising driving rolls adapted for rictional engagement with the walls ot a drill hole disengageably connected with said nut.

11. In combination with a drilling bit having cutting blades adapted for advancement obliquely to its axis; a rotatable' fcc( nut adapted for causing said advancement diametrically opposed power blocks adapte( for mutual reaction through interposed com ,naomi pres-sion Springs and having rollers' aflantecl for frictional engagement with the vwal of a (li'ill hole; and flexible means for delivering power from Said rollers to said nut.

l2. In combination Willa a drillingl bi having cutting blades adapted foi` advanceinem obliquely to its axis: a rotatable 'leed nut adapted for causing; said advancement; dialneirically opposed power blocks having 10 interposed compression springs anfl rollers aflaated 'for iictional ongpgomen will 'rle wal s of a glrill hole; and flexible means for delivering power 'from saiil rollers to said nut; said means beingr automatically dise gageable from said nut when the latine;r has made a preefletei'lninefl nmnnei olE revolu- ,f/ions and adapt'erl loi' lmnp; controlled by plunger rods normally projecting 'from the end of said bil'.

GEORGE B. L() UDERBACK.

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