US2044349A - Hydraulic rotary drill - Google Patents

Description

June 16, 1936. w. L. DIEHL 2,044,349

HYDRAULIC ROTARY DRILL I Filed Feb. 16, 1952 4 Sheet-Sheet 1 gwnliov June 16, w DIEHL HYDRAULIC ROTARY DRILL Filed Feb. 16, 1932 4 Sheets-Sheet 2 :gwx am Huunu June 16, 1936. w LY DlEHL 2,044,349

HYDRAULIC ROTARY DRILL Filed Feb. 16, 1932 4 Sheets-Sheet 3 NITED STATES PATENT OFFICE HYDRAULIC ROTARY DRILL Webster L. Diehl, St. Joseph, Mo.

Application February 16, 1932, Serial No. 593,277

Claims.

This invention relates to well drilling apparatus.

Specifically referred to herein will be that type of well drilling apparatus which, practically continuously during operation, is made effective by means of a drill-point deriving its power from a fluid-operated turbine. This turbine, in one form of the invention, is carried within a long shaft, extending down into the ground. In a preferred case, the shaft, as it moves into the well being prepared for it by the drill-point, is itself rotated by power means independent of the turbine.

The factor of the great mass of shafts such as these, which are generally of great length, and the large amount of power necessarily used in effecting their rotation, is probably the most vital one in making desirable the operation of the drill-point by independent power means. Since some fluid, such as water, is customarily forced down the shaft to discharge around the drillpoint, acting as a lubricant in facilitating the drill operation and carrying away dbris formed as the drill-point is active, the hydraulic pressure of this fluid may be made to actuate the turbine and rotate the point. However, during the operation of these drill-points, it occasionally happens that the power developed by the turbine is insuificient to overcome the resistance of some obstruction of greater impenetrability than the ground through which the drill-point is moving. In such case, in spite of continued flow of fluid through the turbine, rotation of the drill-point will cease and the apparatus would become ineffective. Even continued rotation of the shaft itself from its independent power means would be ineffective to rotate the drill.

It is an object of the invention to provide means for coupling the drill-point directly to the shaft on such occasions when the drill-point does not derive sufficient power from the fluid to overcome such increased resistance. For this purpose, between the shaft and the drill-point, there may be provided a coiled member having an end affixed to one of them. The other end of the member is provided with means cooperating with a complementary portion on the part to which it is not secured so that the shaft and the point may unhindered rotate relatively in one direction; upon commencement of relative rotation in the opposite direction, interlocking of the end of the member and the cooperating portion will ensue.

Rotation of the drill-point, when driven by the turbine, is generally at a higher rate than that of the shaft so that normally the drill-point and the shaft will rotate relatively in one direction. Should the turbines power become insufiicient, or the drill-point be stopped against an obstruction, or its rotation cease for any other reason, and if the shaft continue. rotating, the direction of relative rotation of drill-point and shaft will be reversed, and immediately there will result an interlock between the free end of the member and the cooperating portion. The coiled member will be forced to expand, and. by its expansion, caused to engage cooperating portions of the shaft and the drill-point. Expansion of the member will continue until it grips these portions so tightly as to form a substantially rigid coupling between them, in which case the drill-point will then be driven positively from the rotating shaft. After the drill-point has cleared its obstruction, the coiled spring will, by its own elasticity, tend to return to its original formation and release the point and the shaft of their interengagement, whereupon the turbine will resume driving the drill-point until the next obstruction is met.

To safeguard the several parts of drilling apparatus, sunk in the well and inaccessible practically at all times after operation commences, lubrication under pressure has become arequisite. It is an object of the invention to provide, for well drills of this character, a lubrication system in which the fluid under pressure, necessary for turbine operation and for dbris elimination, is made the active agent in maintaining lubricant at the several parts under pressure greater than that of any neighboring fluid source. The resultant pressure of the lubricant at operating parts located beyond the turbine, is much higher than the fluid pressure at this location, since the pressure head loss in the turbine reduced it much below the original fluid pressure, and the pressure of the lubricant. Infiltration of water into the lubricant is thus substantially eliminated, as the tendency, in such case, is that lubricant pass out of the lubricated parts.

It is an object of the invention to provide a system of gearing by which the relatively slow speed drill-point may be driven by the customary high minimum speed turbine. In one case, the principle of the epicyclic gear train is used, while in another case, an annular gear is driven by a pinion on the turbine shaft. In the form using the epicyclic train, the annular gear is preferably stationary with the drill shaft, while the p anetary gears are affixed in a member coupled to the drill-point. It is also desired that such system of gearing be arranged to permit readily interchanging sets of gears for obtaining different ratios of reduction.

While a high degree of reduction may be effected in the system using an annular gear, driven by a pinion gear on the turbine shaft, it is, however, desirable to reduce the turbine speed as much as possible without affecting the power derived. For this purpose, the turbine may be built in a substantially large number of stages so that the pressure drop in each stage will be decreased, whilethe effective power delivered will be the same.

In normal operation, the drill-point, driven by the turbine, should rotate at a speed greater than that of the drill shaft. It is desirable that the operator may determine if and when the drill .is being driven by the shaft itself for any continuous period, so that he may remedy immediately any emergency that may have arisen. With the drill and the turbine entirely incased and within the ground, direct observation is not practical. It is an iectnfiheiarenii nialt de wh'erebyianoperatonmay.determineQatiany "life during drillin ..thmrelmiras ead Of rill-point and dfill shaft. thisiiui poseftlfere is mounted upon the turbine shaft, a spring member which, by contacting a stationary point on the shaft, may complete a circuit for a gong or like indicator, externally of the apparatus. e. number of indications for a unit time will irg r ,itriefdpratdrfwfi g drill-point is being drivenbywturbineior,shaftl Inthe l'at't'ercase, the gong would not time at. all.

Other objects of this invention will hereinafter be set forth, or will be apparent from the description and the drawings, in whichare illustrated embodiments of apparatus for carrying out the invention.

The invention, however, is not intended to be restricted to any particular construction or arrangement of parts, orto any particular application of such construction, or to any specific manner of use, or to any of the various details thereof, herein shown and described, as the same may be modified in various particulars or be applied in many varied relations without departing from the spirit and scope of the claimed invention, the practical embodiments herein illustrated and described merely showing some of the various forms and modifications in which the invention might be embodied.

On the drawings, in which the same reference characters refer to the same parts throughout, and in which are disclosed preferred embodiments:

Fig. 1 is an elevational view of the entire drill shaft, illustrating the arrangement of the drillpoint and associated elements;

Fig. 2 is a View in perspective of the apparatus within the shaft from the topmost portion to the gear cut on the shaft and driven by the turbine;

Figs. 3, 4 and 5, in the order named, are sectional views, to an enlarged scale, longitudinally of a drill shaft, parts being shown in elevation, and all taken together showing the shaft as arranged and embodying the invention;

Fig. 6 is a detail sectional view to a still larger scale, parts being shown in elevation, illustrating the outlet from the lubricant compression chamber;

Fig. 7 is a transverse sectional view on the line 1-1 of Fig. 4, to the same scale as Fig. 6;

Fig. 8 is a transverse sectional view on the line 8-8 of Fig. 4, to the same scale as Fig. 6;

Fig. 9 is a transverse sectional view on the line In one form of apparatus for 9-9 of Fig. 5, illustrating, to an enlarged scale, the arrangement of the end of the coiled coupling device; and

Fig. 10 is an elevational view, to the same scale as Fig. 9, of parts including the'coiled coupling member of the drill-point drive, some of the parts being shown in section.

The drill shaft in, here illustrated as embodying the invention, consists of a shell I2 within which preferably are housed all elements normally necessary for carrying on drilling. At the top of the shell is generally situated an orifice member M, the effective cross-section of which, at point I 6, determines the quantity of fluid flowing down through the system.

The shell may be made up of a plurality of separable sections, the topmost of which may be member l4, threadedly engaged, or in any other suitable manner retained assembled, to form the shell. Preferably just beneath member I4 is located a cylinder I8 of uniform bore within which is reciprocable a piston 20. The topmost portion of cylinder I8 is open to the interior of the shell at this point, a cap 22 having an opening 24 permitting limited admission of fluid into the chamber 25 defined by cylinder I8 and piston 20.

The cylinder is engaged by a coupling 28, or in any other manner is secured to a valve housing 30, which may be an integral part of a casting 32. The outer wall 34 of the casting preferably forms a continuation of shell I2, the housing being spaced away from the wall by means of ribs 36 to provide passages 38 for fluid flowing around the housing. The housing is provided with a passage 49 across which, at an intermediate point, a plug 42 is movable by screwing it in and out of a threaded wall 44. Access to the plug and its lock nut 45 may be had through an opening 45 in wall 34, which is normally closed by a plug 50. Adjustment of plug 62 results in a variance of the effective cross-section of passage 40, and, therefore, in control of the amount of lubricant passing down through the passage.

Housing 35 may also provide an upper bearing for turbine shaft 52 over which is received a sleeve 55. To provide against leakage of lubricant between shaft and sleeve, rings 56 are disposed upon the shaft. The lubricant passes from passage 58, entering at the upper end of the shaft a passage 58 through the shaft. Roller bearings 65 may be carried. by a suitable race for reducing friction between housing 35 and the sleeve when the shaft rotates. The seal formed by spring-pressed washers 52 and packing 64, forced tightly around the shaft by means of a compresser 65 engaged against the end of the housing by suitable means, prevents passage of lubricant into the shell of the drill shaft.

The passage 58, formed through the shaft, extends down into housing 68 and into the chamber 75 in which it discharges. Preferably immediately below housing 36, shaft 52 has mounted upon it, in any desired manner, the vanes 12 of turbine 14 so located as to cooperate with stationary vanes 16, formed with, or otherwise secured to, a sleeve '18 forming a part of shell l2. Preferably, the vanes are arranged in a plurality of successive stages, the number of stages being such that the effective speed of the rotating shaft will be low, the drop in pressure between stages being sufficiently reduced for this purpose, whereas, by disposing a suflicient number of stages, practically the entire power derivable from fluid under pressure will be transmitted by the turbine to shaft 52.

Beyond the turbine, the shaft enters housing 68. The upper end of the housing is protected against inflow of fluid by means of a stufling box 80 and the spring-pressed seal 82. The housing is supported from a sleeve 84 by ribs 86, thus leaving passages 88 around the housing for fluid flow. A shoulder 90 internally of the housing provides support for a ball race 92, which forms a bearing for the turbine shaft. Adjacent its end, the shaft has a gear 94 cut in its surface. The lower end of the shaft preferably is slightly beveled and rests upon roller bearings 96, set slightly at an angle to act as a bottom bearing for the shaft. Forming a part of housing 68 and preferably assembled therewith in any desired manner is an annulus 98 which, on the same level as gear 94, has cut therein teeth to form an annular internal gear I00. The annulus is braced away from the shell by means of lugs I02.

Between gears 94 and I are positioned a plurality of pinions I04, meshing with both gears. These pinions are carried by pins I06 between which and the pinions the roller bearings I08 are assembled. The pins are supported in a cage IIIJ formed at the upper end of a shaft H2. The cage has a recess II4 for receiving the end of shaft 52 and roller bearing 96. Pins I06 have both top and bottom bearings in the cage. Ball races H6 and H8 permit relative rotation of shaft H2 and annulus 98.

Lubricant entering chamber I0 passes down over ball races 92 and H6, through chamber I20, formed by annulus 98, and sealed off at its lower end by a stuffing box I22 and spring-pressed members I24. From chamber I20, lubricant passes down through a passage I26, preferably centrally formed in shaft II2, to discharge into a tube I28, immediately at the end of shaft II2, which tube collects and conducts away the lubricant as hereinafter further indicated.

It will be noted that, as shaft 52 is rotated by the turbine, it drives the epicyclic train constituted by gear 94, pinions I04 and gear I00, to rotate shaft II2 relatively to the relatively stationary annular gear I00. The degree of reduction will be determined by the proportional sizes and disposition of the gears.

On shaft H2, immediately below stufiing box I 22, may be secured a spring finger I36 having a contact button I32 at its outer end. This button is positioned and is intended to. contact wilh a button I34 carried by an insulator I36 secured to the shell. A suitably insulated conductor may pass up through the passages within the shell, or in any other manner be brought to the surface, where, by means, such as a commutator, the make-and-break action of the two buttons may be used to energize some suitable appliance (not shown), such as a gong, for indicating the number of times the buttons make contact, whereby it is possible to determine the relative rotational speed of shaft I I2 and the shell.

The end of shaft I I2 is splined or otherwise retained against rotation relative to a tubular shaft I38. Immediately below the beginning of shaft I38, and tube I 28 and its sealing washer I40, a

passage I42 is provided through the wall of shaft I38 for the entrance of fluid from the drill shell into the duct I44 provided centrally of shaft I38. This duct extends through the entire length of the shaft down to drill-point I46 at which the fluid discharges, facilitating operation of the point and washing away dbris formed and driving such debris upwardly away from the drill-point.

guul VII Tube I28 is bent over, as shown at I48, and retained by a suitable finger I50 against the wall of shaft I38, along which it extends to a chamber I52, defined by suitable packing glands at top and bottom of sections I54 and I56, forming part of the shell, and into which it empties.

Within the chamber I52 and encircling shaft I38 is a coiled spring I58, the upper end of which terminates in an upright prong I60. An opening I62 is provided in section I56 Within which prong I60 is engaged. The lower end of the spring may be formed with a sharp pointed tooth I64 which, by the pressure of the spring, is forced into engagement with a ledge I66 of a shouldered sleeve I68, which is secured to the drill-head socket I10 by any suitable means. Tooth I64 is intended normally to ride over teeth I12 in the ledge, that is, normally the rotation of the shaft will be such that sleeve I 68 will slide by the relatively stationary spring I58. If, however, rotation of the sleeve, which is splined to shaft I30, should no longer be effected by the turbine, and the shell, continuously rotated by suitable power means (not shown), should continue so to rotate, teeth I64 and H2 will engage. Immediately, as will be seen from Fig. 10, expansion of coiled spring I58 will occur, until finally the spring will engage against the substantially co-axial and equiradial walls I14 and I76 of section I56 and sleeve I68, thus coupling these two pieces together and making them as one so that the section will transmit power to the sleeve as the shell rotates. In other words, the drill-point I46 will thus be directly coupled to the shell and be driven thereby. A suitable roller bearing I18 may be positioned be tween the sleeve and section I56 for Well known purposes.

It is to be noted that, in the case of the gear reduction described, the elements are mounted within separable sections of the shell, permitting ready dissociation and assembly, either for replacement or, as here in case of the gears and turbines, to permit variation of the relation of the parts to each other, by introducing more stages into the turbine, or by changing the gear relationship.

Many other changes could be effected in the particular apparatus designed, and in the methods of operation set forth, and in the specific details thereof, without substantially departing from the invention hereof intended to be defined in the claims, the specific description herein being merely to illustrate operative embodiments carrying out the spirit of the invention.

What is claimed as new and useful is- 1. In well-drilling apparatus including a drill casing, means for causing rotation of the casing, a drill-point, means carried by the casing for efiecting rotation of the drill-point relative to the casing, and resilient means to couple the point directly to the casing when the rotation-effecting means is ineffective to cause such relative rotation, the coupling action becoming more intense with increased transmission of force therethrough.

2. In well-drilling apparatus including a drill casing, means for causing rotation of the casing, a drill-point, means carried by the casing for effecting rotation of the drill-point at greater speed than the casing, and means to couple the 70 point directly to the casing when the rotationefiecting means is inefiective to produce such greater speed, the coupling action becoming more intense with increased transmission of force therethrough. 7 5

QTI

3; In well-drilling apparatus including a drill casing, means for causing rotation of the casing, a drill-point, a fluid-actuated motor carried by the casing for efiectmg rotation of the drill-point relative to the casing, and means to couple the point directly to the casing when the motor is ineffective to cause such relative rotation, the coupling action becoming more intense with increased transmission of force therethrough.

4. In well-drilling apparatus including a drill casing, means for causing rotation of the casing, a drill-point, means carried by the casing for effecting rotation of the drill-point relative to the casing, and means for forming an interconnection between the point and the casing and secured to one of them, said interconnecting means, when the rotation-effecting means is ineffective to cause such relative rotation of point and casing, positively engaging the other of them to drive the point directly from the rotating casing.

5. In well-drilling apparatus including a drill casing, means for causing rotation of the casing, a drill-point, means carried by the casing for effecting rotation of the drill-point relative to the casing, and means for forming an interconnection between the point and the casing and secured to one of them, said interconnecting means including a resilient member which, when the rotationefiecting means is ineffective to cause such relative rotation of point and casing, positively engages the other of them to drive the point directly from the rotating casing.

6. In well-drilling apparatus including a drill casing, means for causing rotation of the casing, a drill-point, means carried by the casing for effecting rotation of the drill-point relative to the casing, and means for forming an interconnection between the point and the casing and secured to one of them, said interconnecting means including a coiled spring which, when the rotationeffecting means is ineffective to cause such relative rotation of point and casing, positively engages the other of them to drive the point directly from the rotating casing.

7. In well-drilling apparatus including a drill casing, means for causing rotation of the casing, a drill-point, means carried by the casing for efiecting rotation of the drill-point relative to the casing, and means for forming an interconnection between the point and the casing and secured to one of them, said interconnecting means including a coiled spring which, when the rotation-effecting means is ineffective to cause such relative rotation of point and casing, is uncoiled and positively engages the other of them to drive the point directly from the rotating casing.

8. In well-drilling apparatus including a drill casing, means for causing rotation of the casing, a drill-point, means carried by the casing for effecting rotation of the drill-point relative to the casing, and a coiled spring between the point and the casing and secured to one of them, the other having means for engagement by the spring, said spring being normally of an efiective diameter less than that of the casing and of a diameter to maintain it out of engagement with the engagement means, but when the rotation-effecting means is ineffective to cause such relative rotation of point and casing, positively engaging the engagement means to drive the point directly from the rotating casing.

9. In well-drilling apparatus, a drill casing carrying a drill-point. and means for rotating the point including a liquid flow actuated device for energizing the point, m eans.ior. l ubricating the ggyln cnwmi lthae naratuslsaidrm ing the liguid atth e p r e ssure before a jlaencaalanau th -H t, d" "fvice', and the liquid from"'tliedvice discharging a SAQ RQIH S a MM" mung lubricant.

"TOTIKWell-drilling apparatus including a drill shell, a drill-point, means for rotating the shell, means in the shell for rotating the point relatively to the shell, and means for coupling the point to be driven by the shell when the point rotating means becomes inefiective and means iglilllifittillgi fl ,n latiitatspeedsmqi. Q2 telllll hdsp 11. In well-drilling apparatus including a drill casing, a drill-point, means for rotating the casing, an hydraulically operate-d motor assembled within the casing for effecting rotation of the point relative to the casing, and transmission means within the casing and between the point and the motor; an enclosing chamber for the transmission means; the transmission means including a member coupled to the point and extending into the chamber, a shaft extending from the motor and into the chamber, and gearing between the member and the shaft within the chamber; the liquid discharge from the motor passing down through the casing around the chamber, the chamber being filled with lubricant in which the gears operate, and means to maintain the lubricant under pressure to prevent leakage of the discharged liquid into the chamber.

12. In a well-drilling system including a casing for movement into the well as it is drilled, the casing being rotated, means for retaining a drillp-oint, means for operating the drill-point retaining means, the operating means being directly coupled to the drill-point retaining means, the drill-point retaining means having a wall formed to be substantially co-extensive with the casing wall, the drill-point retaining means and the casing normally providing a pair of relatively rotatable members, a coiled spring, one end of the spring being secured to one of the members, and means on the other member for engaging the other end of the spring to cause it to uncoil into engagement with the walls when the operating means becomes ineffective, whereby the drill-point retaining means and the casing will be caused to move as a unit.

13. In well-drilling apparatus, a drill casing,

means for causing rotation of the casing, a drillpoint, means carried by the casing for rotating the point relatively to the casing, a resilient member extending between the casing and the point and fixedly engaging one of them, and

means for effecting engagement between the resilient member and the other of them to force the member into coupling relation with casing and point and secure direct drive relation between casing and point, the engagement-effecting means becoming operative when relative rotation ceases.

14. In well-drilling apparatus, a drill casing, means for causing rotation of the casing, a drillpoint, means carried by the casing for rotating the point relatively to the casing, the casing and point being formed with adjacent inner walls of substantially the same radius of curvature, a resilient member extending between the casing and the point and fixedly enga ing one of them, the

1,. beinacgndl isd .1 points bflQYUh resilient member normally being out of engagement at least with the wall of the other, and means for effecting engagement between the resilient member and the wallsto force the member into coupling relation with casing and point and secure direct drive relation between casing and point, the engagement-effectingmeans becoming operative when relative rotation ceases.

15. In well-drilling apparatus, a drill casing, means for causing rotation of the casing, a drillpoint, means carried by the casing for rotating the point relatively to the casing, the casing and point being formed with adjacent walls of sub stantially the same radius of curvature, a resilient member extending between the casing and the point and fixedly engaging one of them, a toothed wall on the other, the resilient member normally being out of engagement at least with the wall of the other and having a free end normally moving over the toothed wall, said free end being adapted positively to engage the toothed wall and to force the resilient member to engage both walls to force the member into coupling relation with casing and point and secure direct drive relation between casing and point, said free end becoming effective when relative rotation ceases.

16. In well-drilling apparatus including a drill casing, a drill-point, means forrotating the casing, means assembled with the casing for effecting rotation of the point relative to the casing, transmission means between the point and its rotating means including a member coupled to the point and carrying a planetary gear, an annular gear fixedly associated with the casing and engaged by the planetary gear, a shaft extending from the point-rotating means and having a sun gear thereon engaging the planetary gear, the casing and the point being formed with walls of substantially the same radius of curvature, a resilient member extending between the casing and the point and fixedly engaging one of them, and a toothed wall on one of them, the resilient member normally being out of engagement at least with the wall of one of them and having a free end normally moving over the toothed wall and adapted to engage a tooth of said toothed wall when relative rotation between casing and point ceases, thereby forcing the resilient merriber to engage both walls, whereby the membe is forced into coupling relation with casing and point and secures direct drive relation between casing and point. I

17. In a well-drilling system including a casing for movement into the well as it is drilled, the casing being rotated, said casing having a chamber defined therein, a drill-point socket, means within the chamber for operating the socket, the operating means being directly coupled to the socket, and resilient means for effecting a coupling directly between the socket and the casing when the socket-operating means becomes ineffective, whereby the socket and the casing will be caused to move as a unit.

18. In a well-drilling system including a casing for movement into the well as it is drilled, the casing being rotated, a drill-point socket, means for operating the socket, the operating means being directly coupled to the socket, and resilient means for effecting a coupling directly between the socket and a wall of the casing when the socket-operating means becomes ineffective, whereby the socket and the casing will be caused to move as a unit.

19. In a well-drilling system including a casing for movement into the well as it is drilled, the casing being rotated, a drill-point socket, means for operating the socket, the operating means being directly coupled to the socket, and

a coiled spring for effecting a coupling directly 5 between the socket and a wall of the casing when k the socket-operating means becomes inefiective, whereby the socket and the casing will be caused to move as .a unit.

20. In a well-drilling system including a cas- 0 ing for movement into the well as it is drilled, the casing being rotated, a drill-point socket, means for operating the socket, the operating means being directly coupled to the socket, the socket having a wall, and a coiled spring for effeet-ing a coupling directly between the walls of the socket and the casing when the socket-operating means becomes inefiective, whereby the socket and the casing will be caused to move as a unit.

21. In a well-drilling system including a casing for movement into the well as it is drilled, the casing being rotated, a drill-point socket, means for operating the socket, the operating means being directly coupled to the socket, the socket having a wall formed to be substantially co-extensive with the casing wall, and a coiled spring for effecting a coupling directly between the walls of the socket and the casing when the socket-operating means becomes ineffective, whereby the socket and the casing will be caused to move as a unit.

22-. In a well-drilling system including a casing for movement into the well as it is drilled, the casing being rotated, a drill-point socket, means for operating the socket, the operating means being directly coupled to the socket, the socket having a wall formed to be substantially co-extensive with the casing wall, and a coiled spring for uncoiling to form a coupling directly between the walls of the socket and the casing when the socket-operating means becomes inefiective, whereby the socket and the casing will be caused to move as .a unit.

23. In a well-drilling system including a casing for movement into the well as it is drilled, the casing being rotated, means for retaining a drill-point, means for operating the drill-point retaining means, the operating means being directly coupled to the drill-point retaining means, the drill-point retaining means having a wall, the drill-point retaining means and the casing normally providing a pair of relatively rotatable members, a coiled spring, one end of the spring being secured to one of the members, and means on the other member for engaging the other end of the spring to cause the spring to effect a coupling directly between the walls of the drill-point retaining means and the casing when the operating means becomes ineffective, whereby the drill- 0 point retaining means and the casing will be caused to move as a unit.

24. In a well-drilling system including a casing for movement into the well as it is drilled, the casing being rotated, means for retaining a drillpoint, means for operating the drill-point retaining means, the operating means being directly coupled to the drill-point retaining means, the drill-point retaining means having a wall, the drill-point retaining means and the casing nor- 7O mally providing a pair of relatively rotatable members, a coiled spring, one end of the spring being secured to one of the members, and a ratchet on the other member for engaging the other end of the spring to cause thefspring to effect a coupling directly between the Walls of the drill-point retaining means and the casing when the operating means becomes inefiective, whereby the drill-point retaining means and the casing will be caused to move as a unit.

25. In a well-drilling system including a casing for movement into the well as it is drilled, the casing being rotated, means for retaining a drillpoint, means for operating the drill-point retaining means, the operating means being directly coupled to the drill-point retaining means, the drill-point retaining means having a wall, the

drill-point retaining means and the casing normally providing a pair of relatively rotatable members, a coiled spring, one end of the spring being secured to one of the members, and means on the other member for engaging the other end of the spring to cause it to uncoil into engagement with the walls of the socket and the casing when the operating means becomes ineffective, whereby the drill-point retaining means and. the casing will be caused to move as a unit.

WEBSTER L. DIEHL.

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