US3768579A

US3768579A - Drill pipe breakout mechanism

Info

Publication number: US3768579A
Application number: US00212113A
Authority: US
Inventors: H Klein
Original assignee: Robbins Co
Current assignee: Robbins Co
Priority date: 1971-12-27
Filing date: 1971-12-27
Publication date: 1973-10-30
Anticipated expiration: 1990-10-30
Also published as: AU471058B2; DE2263428A1; CA976951A; AU4997772A; JPS5550159B2; DE2263428C2; ZA728887B; SE403813B; ZM19472A1; JPS4873301A

Abstract

First and second collar like wrench members having radially outwardly directed peripheral teeth are respectively locatable about a turning wrench flat region of an upper section of drill type and a holding wrench flat region of the next lower section of drill pipe. The lower wrench member is held by a holding wrench having inwardly directing teeth for engaging complementary teeth on the holding wrench member. A drill head includes a breakout wrench having radially inwardly directed teeth which are engageable with the teeth on the upper wrench member. The upper section of pipe is thread connected to a collet internally of the drill head which is free to float axially relative to the breakout wrench on the drill head. The collet is spline connected to the drill head so that it rotates along with the drill head. The axial float permits the drill head to be hydraulically raised and lowered relative to the collet. The drill head is raised to provide room below the breakout wrench for installation of the upper wrench member, and is lowered to bring the teeth of the breakout wrench into engagement with the teeth of the upper wrench member. The collet is supported within the drill head for sideways pivotal movement in all directions, so that bending stresses are not transmitted from the drill pipe to the rotary drive mechanism for the drill head.

Description

United States Patent Klein Oct. 30, 1973 [54] DRILL PIPE BREAKOUT MECHANISM spectively locatable about a turning wrench flat region [75] Inventor: Harold T. Klein, Bellevue, Wash. of an "P Secnon of type a a f s wrench flat region of the next lower section of drill pipe. The

[ l Asslgneel The Robbins p y, Seame, lower wrench member is held by a holding wrench Washhaving inwardly directing teeth for engaging comple- [22] Filed: Dec 27 1971 mentary teeth on the holding wrench member. A drill 21 Appl. No.: 212,113

Primary ExaminerErnest R. Purser Attorney-John O. Graybeal et al.

[57] ABSTRACT First and second collar like wrench members having radially outwardly directed peripheral teeth are rehead includes a breakout wrench having radially inwardly directed teeth which are engageable with the teeth on the upper wrench member. The upper section of pipe is thread connected to a collet internally of the drill head which is free to float axially relative to the breakout wrench on the drill head. The collet is spline connected to the drill head so that it rotates along with the drill head. The axial float permits the drill head to be hydraulically raised and lowered relative to the collet The drill head is raised to provide room below the breakout wrench for installation of the upper wrench member, and is lowered to bring the teeth of the breakout wrench into engagement with the teeth of the upper wrench member. The collet is supported within the drill head for sideways pivotal movement in all directions, so that bending stresses are not transmitted from the drill pipe to the rotary drive mechanism for the drill head.

9 Claims, 11 Drawing Figures Pmimfnnm so can :3. 768.579

sum 1 OF 3 & T 1

M 11 WM/AMJ.

PATENIEDnmao ma 3,768,579 SHEET 3 BF 3 Ado/0 %Maw0 DRILL PIPE BREAKOUT MECHANISM BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to sectional drill stems or shafts comprising a plurality of pipe sections joined together by threaded pin and box type tool joints. More particularly, it relates to auxiliary apparatus for rotatably coupling the drill head to the drill stem at a time when the upper threaded tool joint between the two is loose, so that the drill head can be rotated in a reverse direction to in turn rotate the section of drill pipe threaded to it, for breaking or loosening the lower tool joint of such pipe section without unscrewing the upper tool joint. The invention also relates to various details of holding and turning wrenches, collar like turning and holding breakout wrenches.

2. Description of the Prior Art The most conventional practice of breaking drill stem threaded tool joints involves the use of tongs or manually applied portable power wrench mecanisms which require hard manual work, and in addition they made the breakout operating both hazardous and time consuming.

US. Pat. No. 3,239,016 granted on Mar. 8, 1966, to Emmett L. Alexander discloses a breakout method and apparatus in which neither tongs nor manually applied power mechanisms are used. Instead, the pipe sections are constructed to include a square headed extension at the pin end thereof and a square socket of complementary shape internally of the pipe at the box end. In use, the portion of the drill stem portion below the uppermost section is secured against both rotary and axial movement and the drill head is reversed to cause a random loosening of either the upper or lower threaded tool joints of the upper section of drill pipe. If the lower joint loosened first, the upper section of pipe is rotated until the threads are completely decoupled. Then, the drill head and the upper section of pipe attached thereto are raised until the square head of the extension is engaged within the square'socket'of the second section. Then, the drillhead is again reversed to cause. first a loosening and then a complete decoupling of the tool joint at the upper end of the upper section. If the upper tool joint is the first to loosen, the drill head is reversed until the threads of such joint are entirely disengaged, and then the drill head is moved axially upwardly to place a square headed depending section of an axial extension of the drill head inside the square socket within the upper end of the upper section of drill pipe. Then, the drill head is reversed to first loosen and then entirely disengage the threads of the lower tool joint.

Applicants prior US. Pat. Nos. 3,463,247 and 3,554,298 disclose a system in which the drill head is provided with an auxiliary wrench having jaws which during use are spaced radially outwardly from opposed depressions or flats in the upper section of drill pipe. Insert elements are inserted laterally into the spaces between depressions and the jaws, to substantially completely fill such spaces. A horseshoe type holding wrench or the like is used for engaging the second pipe section at a holding table. Breakout torque is transferred to the upper pipe section from the jaws, to the insert elements, to the depressions, during reverse drive of the drill head.

U.S. Pat. No. 3,446,284, granted May 27, 1969, to Norman D. Dyer and Roy L. VanWinkle, discloses apparatus similar to that shown by applicants prior US. Pat. Nos. 3,463,247 and 3,554,298, except that the drill head is provided with an external axially moveable sleeve and mechanism for moving it axially downwardly relative to the drill head and the frame on which the drill head is supported, and auxiliary mechanism for rotating it in the breakout direction. The sleeve is moveable downwardly into surrounding engagement with a wrench member installed about a surface depression region on the drill pipe.

SUMMARY OF THE INVENTION The drill pipe of the present invention is like the drill pipe disclosed by applicants aforementioned US. Pat. Nos. 3,463,247 and 3,554,298. Such pipe comprises a threaded pin at one end, a threaded box at the other end, and external auxiliary torque transfer means at one end only, located axially inwardly of the tool joint component at such end.

A disadvantage of the known drill head carried breakout apparatuses of the prior art is that they all require rotation of the drill head relative to the surface depressions of the pipe before the wrench surfaces of the breakout wrench can be brought into engagement with the wrench members received in the surface depressions. Also, in apparatuses of the type shown by applicants aforementioned US. Pat. Nos. 3,463,247 and 3,554,298, wherein a wrench member is slipped laterally into place between the recesses and the turning wrench jaws, the lateral through openings which are required structurally weaken the drill head and results in a wrench which can only apply torque to opposed sides of the drill pipe.

The breakout apparatus of this invention is primarily characterized by breakout and holding wrenches which encompass full circles and each includes a large number of torque transferring teeth, and by a pair of collarlike wrench members, one for engaging the turning wrench recesses of an upper section of pipe and a second for engaging the holding wrench recesses of the second section of pipe, and each including peripheral teeth'for engaging the teeth of the breakout and holding wrenches, respectively.

In preferred form the collar-like wrench members are provided with wrench surfaces of dihedral form so that several degrees of rotation of the wrench member relative to the drill pipe section it surrounds is possible. The amount of rotational movement is at least the angular width of a gear tooth, so that enough rotational movement of the wrench member can always occur to allow engagement of the breakout or holding wrench teeth with the teeth ona wrench member, without drill head rotation being necessary. The large number of teeth provide even distribution of turning forces substantially all around the wrenches and the pipe, and the full ring nature of the wrenches results in a system which is quite structurally sound.

The circular wrench member has four wrench surfaces which act upon all four wrench surfaces on the pipe, reducing the load on each wrench surface. Additionally, a four point thrust (pipe weight) exists between the wrench member and the pipe.

According to the invention, the drill head of the apparatus includes inner and outer portions which are spline connected together so that they rotate together but each can enjoy some axial movement relative to the other. In preferred form, the inner member is mounted to float, axially relative to the outer member and the outer member is axially fixed relative to the traveling cross frame and the rotary drive assembly carried thereby. This arrangement permits use of the hydraulic raising and lowering equipment for the traveling cross frame for also (I) lifting the outer portion of the drill head relative to the inner portion and the pipe section secured thereto to provide sufficient room below it for installing the breakout wrench member; for (2) lowering the outer portion of the drill head to place its teeth into engagement with the teeth of the breakout wrench member; for (3) lowering the drill pipe to place the lower holding wrench member into engagement with the holding wrench; and for (4) raising the drill pipe to remove the holding wrench member from the holding wrench; and (5) to provide axial e'nd play during makeup or breakout so that the derrick does not have to follow accurately the thread pitch.

These and other objects, features, advantages, and characteristics of the present invention will be apparent from the following description of a typical and therefore nonlimited embodiment of the invention, as described below in conjunction with the accompanying illustrations.

BRIEF DESCRIPTION OF THE DRAWING section of drill pipe interconnected between the drill head and a second length of drill pipe, with some parts in section to better illustrate certain constructional features, and showing one of a pair of splined collar-type wrench members forming a part of the machine, one of which members is used as a holding Wrench at the worktable during breakout and' makeup of the drill stem, and the other of which is used as a turning wrench at the drive head during certain parts of the breakout operation;

FIG. 3 is a top plan view of one of the wrench members;

FIG. 4 is an enlarged scale fragmentary plan view showing a portion of the holding wrench member engaging the teeth of the worktable holding wrench;

FIG. 5 is a view partially in section and partially in elevation of the components of FIG. 2 but minus the wrench members, and showing the drill pipe in its drilling condition immediately prior to the start ofa breakout operation;

FIG. 6 is a view like FIG. 5, but showing the holding wrench member engaging the second length of drill pipe and being held by the holding wrench at the worktable, and showing the upper end of the upper length of pipe decoupled from the drill head;

FIG. 7 is a view similar to FIGS. 5 and 6, but showing a loose engagement of the threaded joint at the drill head, showing the breakout wrench in place, and showing the threaded joint at the lower end of the upper length of pipe decoupled;

FIG. 8 is a view similar to FIGS. 4-6, but typifying a situation wherein on reverse rotation of the drill head, for random breaking of the upper section threaded joints, the lower threaded joint broke first, such view showing said lower joint decoupled for clarity of illustration;

FIG. 9 is a view similar to FIGS. 5-8, but showing the upper length of drill pipe lowered to a position adjacent the holding wrench table, with the holding wrench engaging the holding wrench surfaces on the upper length of drill pipe, and showing the drill head ready for use to loosen the upper threaded joint;

FIG. 10 is a cross-sectional view taken substantially along line 10l0 of FIG. 7, showing the crosssectional configuration of the drill pipe in the region of the turning wrench receiving surfaces, and showing the turning wrench in its position of use; and

FIG. 11 is an enlarged scale vertical sectional view through the drill head, on the right showing the tool joint member of the drill head down in a position placing the drive wrench surfaces of the drill pipe below the breakout wrench portion of the drive head, and on the left showing the tool joint member floated upwardly and the peripheral teeth of the turning wrench collar in engagement with the teeth of the turning wrench.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, the drilling machine 10 is shown to comprise a base portion 12 which may be firmly an chored to a concrete pad 14 which in turn is anchored to the ground 16. Base portion 12 is shown supporting upstanding guide column means 18 for a traveling cross frame 20. Cross frame 20 includes guide sleeves 22 (FIG. 1) which surroundingly engage the guide column means 18. Hydraulic linear motors or thrust rams 24 are provided for moving the cross frame 20 and the drilling equipment carried thereby up-and-down along the guide column means 18. The drilling equipment carried by the frame 20 includes a drive motor and transmission assembly, indicated generally at 26, and a drill or drive head 28. The motor and transmission assembly 25 is adapted to rotate the drill head 28 in either direction at the selection of the operator.

Base portion 12 also supports a holding wrench table 30, the function of which will hereinafter be described in greater detail.

As shown by FIGS. 2, 59 and 11, the drill head 28 includes a tubular inner portion or collet 32 surrounded by and contained within a tubular outer portion 34. By way of example, inner portion 32 comprises a threaded box type tool joint component and its lower end, designated 36 in the drawing. It also includes a larger diameter upper end portion 38 carrying a ring of external splines 40, and an intermediate portion 42 presenting a convex spherical support surface 44. The outer portion 34 of drill head 28 includes an upper portion 46 provided :with internal splines 48 which mate with the splines 40. It also includes a lower portion 50 having a concave seat 52 of spherical curvature matching the curvature of the surface 44. A turning wrench 54 is secured to the lower end of portion 34. Turning wrench 54 comprises a circular array of teeth 56, e.g., spur gear or spline teeth.

The outer portion 34 of the drive head 28 is coupled to the motor and transmission drive assembly 26, to be directly rotated thereby. Drill head portion 34 is also fixed in position axially relative to the traveling cross frame 20. As a result, for every unit of linear travel of the cross frame 20 there is an equal amount of travel of drill head outer portion 34. And, when the cross frame is fixed in position linearly relative to the rest of the machine the head portion 34 is also fixed in position. The

splines

40, 48 couple the inner drive head portion 32 to the outer drive head portion 34 so that they both rotate together, with the rotating torque being transmitted through the splines. However, the

splines

40, 48 allow the inner drill head portion 32 to float" or travel axially relative to the outer drill head portion 34 and the traveling cross frame 20.

During the drilling operation the spline connection of short teeth 40 with long teeth 48 substantially protects the rotary drive equipment from the bending forces imposed on the drill pipe 5. The spline connection permits enough angular deviation (e.g., plus and minus about 3) of the collet 32 relative to the rotary drive shaft DS, so that deviation tends to occur between members 32, DS rather than bending. Initially, actual deviation is prevented by use of a bushing (not shown) at the table for guiding the pipe S. As drilling proceeds deviation is prevented by drill hole guidance of the drill pipe. Pivotal movement at the

splines

40,48 occurs regardless of whether the

surfaces

44, 52 are together or separated.

The tool joint 36 receives a complementary threaded pin type tool joint component 58 located at the upper end of a length of drill pipe 60, or at the upper end of some other drill pipe component. Immediately axially inwardly of tool joint component 58 there is a first annular shoulder 62 which abuts against the lower end surface of the drill head box type tool joint 36. A first set of wrench surfaces 64 (e.g., a set of four, quadrate flats) is spaced axially inwardly of shoulder 62. A second shoulder 66 is spaced axially inwardly of the wrench surfaces 64. And, a second set of wrench sur; faces 68 is spaced axially inwardly of shoulder 66. As will hereinafter be explained in' detail, the flats or wrench surfaces 64,68 are snuggly and surroundingly engaged by a collar-like wrench member WM.

The

spline connection

40, 48 permits a sufficient amount of axial float of the inner drill head member 34 to result in the wrench surfaces 64 being spaced below the turning wrench 54 when the inner drill head member 32 is seated down on the outer drill head member 34. When the inner drill head member 32 is coupled to a length of drill pipe 60, or to some other drill pipe member, and the outer drill head member 34 is moved relatively downwardly relative to the pipe sec tion 60 (such as by use of the motors 24 to lower the cross frame 20), the

splines

40, 48 permit the inner head member 32 to float upwardly a sufficient amount to allow engagement of the peripheral teeth 76 on the collar like wrench member WM with the teeth 56 ofthe drill head turning wrench 54 (FIGS. 7 and 11).

Referring to FIGS. 3 and 10, the collar like wrench member WM is adapted to surroundingly engage the drill pipe member 60 in the region of the turning wrench surfaces 64, 68. The wrench member WM includes inner wrench surfaces which are designed to substantially mate with and transmit torque to the pipe wrench surfaces 64, 68. In the illustrated embodiment the wrench WM comprises four generally quadrate wrench surfaces 71. The illustrated wrench member WM is of a two-piece construction, the two

pieces

70, 72 being hinged together at 74. A plurality of splines or teeth 76 are provided on the outer periphery of the wrench member WM. The splines or teeth 76 are engageable by the turning wrench teeth 56 at the lower end of the drill head outer portion 34 when the wrench member WM is installed as a collar around the

wrench surface region

64 or 68 of the drill pipe member 60.

In the illustrated embodiment the pipe wrench surfaces 64 are shown to be planar whereas the wrench member surfaces 71 are of shallow dihedral form. Each surface 71 includes two planar halves 78 meeting together at a radially inwardly pointing apex 80. The de flection (e.g., about 10) of each surface 78 relative to the other surface 78 permits some turning of the wrench member WM relative to the drill pipe member before surface-to-surface contact is made between one set of wrench member surface halves 78 and the drill pipe member surfaces 64. The amount of circumferential adjustment of the wrench member WM relative to the drill pipe member 60 is equal to about at least the circumferential width of a

spline tooth

56, 76. Owing to this arrangement, the operator can locate the wrench member WM about the wrench surface region 64 of the drill pipe member 60 and then move it circumferentially a portion of a tooth width if needed to locate the teeth 76 in position to be engaged by the teeth 56, with rotation of the drill head 28 being unnecessary.

The worktable 30 is formed to include an annular holding wrench HW which includes a generally radially inwardly directed set of splines or teeth 82 which are of similar size and cut to teeth 56 so that the holding wrench I-IW can also receive and engage the teeth 76 of9 wrench member WM if the pipe is not in anal alignment with the machine true center line.

A breakout operation will now be described:

Let it be assumed that in the drilling operation the traveling cross frame 20 and the drill head 28 carried thereby are in the process of being moved upwardly along the guide column 18, and the drill stem S is being withdrawn from the drill hole DI-I. When the upper or first pipe section 60 is wholly above the wrench table 30, and the holding wrench depressions 68 of the second pipe section 60 are in position at the wrench table 30 to receive a wrench member WM, axial'movement of the frame 20 is stopped. The holding wrench member WM is then inserted in place, about the holding wrench depression 68 of the second pipe section 60, and the frame 20 is hydraulically moved downwardly (by rams 24) to place the teeth 76 of the holding wrench member WM into engagement with the teeth 82 of the holding wrerich I-IW. The axial entrances into the teeth 82 are flared so that the wrench member teeth 76 are cammed into engagement with the teeth 82. This entrance design between the two sets of teeth will cause about one-half tooth rotation of the pipe member in either direction. This camming action causes a slight amount of rotation of the wrench member WM during hydraulic movement of either wrench member 54 or wrench member WM within the limits allowed by the dihedrally related wrench surfaces 78, if such rotation is necessary in order for tooth engagement to occur.

The drill head 28 is reversed, i.e., rotated in a tool joint loosening direction, for the purpose of randomly loosening one of the tool joints at opposite ends of the upper pipe section 60. FIG. 6 shows a situation wherein the upper tool joint has loosened first. For the sake of clearer illustration, FIG. 6 shows the two upper joint components separated. However, in actual practice there is not a complete separation, only a loosening of the threads. FIG. 8 shows the lower tool joint having loosened first. In this figure the lower tool joint components are shown to be completely separated. However, again, in actual practice there is no complete separation. Assuming that the random loosening operation caused the upper joint to loosen first. The threads are not totally separated but rather are maintained loosely joined. A turning wrench member WM is placed around the turning wrench region of the upper pipe section, with the wrench surfaces 21 within the recesses 64. The traveling cross frame is then lowered (by rams 24) until the drill head breakout wrench teeth 56 engage the wrench member teeth 76. Here again, the entrances into the two sets of

teeth

56, 76 are flared so that there is a slight camming action, including some rotation of the wrench member WM if necessary, to cause meshing of the teeth 56 with the teeth 76.'After this has been done the drill head 28 is again rotated in the thread loosening direction. The portion of the drill stem S below the upper section 60 is still restrained by v the holding wrench HW by way of the lower wrench member WM. However, the drill head wrench 54 now transmits torque from the drill head 28 to the upper pipe section 60 by way of the upper wrench member WM. This application of torque results in a loosening of the threads at the lower tool joint. With the tool joints at both ends of the upper pipe section 60 now loosened, the upper section 60 can be easily unscrewed and removed from the drill stem S. After this is done the drill head 28 is lowered and coupled to the next pipe section 60 by loosely screwing together its box and the upstanding pin of the next section 44. The drill head 28 is then raised, with the weight of the drill stem S being carried by the loosely engaged threads of the loosely made up tool joint, until such next section is wholly above the holding wrench table 30 and in posi-' tion for removal in the manner described above. The two wrench members WM are again inserted in place. The lower one is lowered into the holding wrench HW (by movement of rams 24) and the drill head 28 is lowered until the wrench 56 engages the upper wrench member WM (also by movement of rams 24). Then, the drill head 28 is reversed as before to loosen the threaded tool joint now at the wrench table. This process is repeated with all subsequent sections of the drill stem S until all sections have been removed from the drill hole DH.

If during the initial reversal of the drive head 28 to cause a random loosening of the initially upper tool joint, the lowerjoint is the first to loosen, then an added stage must be added to the operation in order to effect loosening of the tool joint between the upper section and the drive head 28. This stage involves maintaining the loosened lower tool joint components coupled, so

that their threads may carry the weight of the drill stem sions 68 of the upper pipe section are at the holding wrench station at table 30. As shown by FIG. 9, the holding wrench member WM is reset about the depressions 68 and the assembly is lowered (by rams 24) to place it into engagement with the holding wrench HW, so that the members WM and HW serve to both support the weight of the drill stern S still in the hole, and prevent its rotation. The lowered drill head 28 is then rotated in the joint loosening direction until the threaded tool joint between it and the upper pipe section 60 is loosened. When this happens the joint components are maintained loosely coupled, again so that the threads can carry the weight of the drill stem S, and the drill head 28 is raised to relocate the upper pipe section 60 in a proper position for removal. The holding wrench member WM is reinstalled on the second pipe section 60 and the first section 60, now having both of its tool joints loosened, is easily unscrewed from the second pipe section 60 and from the drill head 28, and is removed from the drill stern S.

It is to be understood that the exact physical charac' ter or construction of the auxiliary torque transfer means, the turning wrench receiving depressions, and the holding wrench receiving depressions, may vary from what is illustrated and described. Although the drive head 28 is shown and has been described as including a threaded box type of tooljoint component, in some installations it might be desirable to provide it with a pin type of tool joint component, in which case the box ends of the pipe sections would be directed upwardly towards the drill head, rather than the pin ends of the pipe as is illustrated. Also, it is to be understood that the present invention is applicable to drilling equipment for drilling generally vertically upwardly, horizontally, or at a slant, as well as to equipment which is used for drilling generally vertically downwardly. And, the wrench collars might be made in three or more sections rather than two sections, as illustrated.

What is claimed is:

1. Drilling apparatus comprising:

a rotary drill head comprising an inner portion including a threaded tool joint component, an outer portion surrounding said inner portion and including a circular array of teeth, and means coupling said inner and outer portions together for joint rotation but permitting relative axial movement of such portions;

a drill pipe member including a complementary threaded tool joint component at an end thereof,

for mating with the threaded drill pipe component of the drill head, and exterior wrench surface means spaced axially inwardly of said member from said threaded tool joint component;

a wrench member installable onto said drill pipe member, in at least a partially surrounding relationship thereto, said wrench member including an inner part engageable with the wrench surface means on the drill pipe member, and an outer portion including teeth engageable with the teeth on the drill head and with the means coupling the inner and outer portions of the drill head together permitting sufficient relative axial movement that the threaded tool joint component of the drill head can be moved relatively axially outwardly of the drive head a sufficient amount to place the wrench surface means of the drill pipemember where the said wrench member can be secured thereto, and can be moved relatively axially inwardly a sufficient amount to place the teeth on the wrench member into engagement with the teeth on the outer portion of the drill head, so that the drill head can be rotated in a direction which would tend to cause loosening of the threaded tool joint and rotational torque would be transferred from the drill head through the teeth on the drill head to the teeth on the wrench member and from the wrench member to the drill pipe member.

2. Drilling apparatus according to claim 1, wherein said drilling apparatus includes a support frame for the rotary drill head and means for moving said support frame axially during the drilling operation, and the outer portion of the drill head is fixed in position axially with respect to said frame, wehrein said inner portion of the drill head is generally tubular and comprises an outboard end portion which includes said threaded tool joint component and an inboard portion which is exteriorly splined, and the outer portion of the drill head includes complementary splines having spaces between them for receiving the splines of the inner portion.

3. Drilling apparatus according to claim 1, wherein the inner part of the wrench member is sized to make a loose enough engagement with the wrench surface means that the wrench member, when it is on said drill pipe member, can be moved circumferentially an amount at least about equal to the circumferential width of a tooth on the drill head or the wrench member.

4. Drilling apparatus according to claim 1, wherein the entrance portions of the teeth on at least one of the drill head and wrench member are shaped to upon relative axial movement cause a camming of the two sets of teeth into engagement in the event of an initial misalignment.

5. Drilling apparatus for use with a drill pipe member having at one end thereof a threaded tool joint component connectible to a complementary threaded tool joint component carried by a rotary drive head, at its a circular array of radially inwardly directed teeth at least partially surrounding said opening; and

a wrench member installable onto the drill pipe member in at least a partially surrounding relationship thereto, said wrench member including an inner part engageable with the wrench surface means on the drill pipe member, and a outer portion including radially outwardly directed teeth engageable with the teeth on said wrench, with the inner part of the wrench member being sized to make a loose enough engagement with the wrench surface means so that the wrench member, when it is on said drill pipe member, is free to move circumferentially an amount at least about equal to the circumferential width of a tooth on the wrench or the wrench member, so that the teeth on said wrench member can be moved into substantial engagement with the teeth on said wrench without rotation of the drill pipe member.

6. Drilling apparatus according to claim 5, wherein the entrance portions of the teeth on at least one of the wrench or the wrench member are shaped to upon relative axial movement cause a camming of the two sets of teeth into engagement in the event of an initial misalignment, attended by circumferential movement of the wrench member.

7. Drilling apparatus according to claim 5, wherein said wrench is a holding wrench which is secured to a worktable portion of a drilling machine.

8. Drilling apparatus according to claim 5, wherein said wrench is a turning wrench which is secured to and rotates with a drill head portion of a drilling machine.

9. Drilling apparatus according to claim 5, comprising both a turning wrench of the type described which is secured to and rotates with a drill head portion of a drilling machine and a holding wrench of the type described which is secured to a worktable portion of a drilling machine.

UNITED STA S PATENT OCFFICE CERTIFICATE OF CORRECTION Patent No. 3,768 ,579 Dated October 30 1973 Inventor(s) Harold Klein It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

FIG. 1 change numeral "2 to 12 v Columnk, line 39, change numeral "25 to 26 Column 6 line 29 delete numeral "9" Column 6, line 29, change "anal" to axial Column 6 line. 30 change "machine" to machine's Column 8, line 34, befored'means" insert spline Column 8, line 36, after "permitting" insert limited-.

Column 8, line #0, change "drill pipe" to tool joint Column 8 lines" 5 53 change "the means coupling the inner and outer portions of the drill head together" to said spline means L Column 8, line 54, after "movement" insert so ColunuTQ, line 8, change "wehrein" to wherein Column 9, line 25, insert a comma after "to".

Column 9 line 26, insert a comma after "movement".

Column 9, line 26, after "cause a" insert rotational Column 9,

line. 27, after "into" insert aligned S igned and sealed this 10th day of December 1974.

(SEAL) Attest:

McCOY M. GIBSON JR. c; MARSHALL DANN Attesting Officer v Commissioner of Patents FORM PO-1050 (10-69) USCOMM-DC scan-Pee .5. GOVERNHENT IRI'I'HNG OFFICE: -3"Js.

Claims

1. Drilling apparatus comprising: a rotary drill head comprising an inner portion including a threaded tool joint component, an outer portion surrounding said inner portion and including a circular array of teeth, and means coupling said inner and outer portions together for joint rotation but permitting relative axial movement of such portions; a drill pipe member including a complementary threaded tool joint component at an end thereof, for mating with the threaded drill pipe component of the drill head, and exterior wrench surface means spaced axially inwardly of said member from said threaded tool joint component; a wrench member installable onto said drill pipe member, in at least a partially surrounding relationship thereto, said wrench member including an inner part engageable with the wrench surface means on the drill pipe member, and an outer portion including teeth engageable with the teeth on the drill head; and with the means coupling the inner and outer portions of the drill head together permitting sufficient relative axial movement that the threaded tool joint component of the drill head can be moved relatively axially outwardly of the drive head a sufficient amount to place the wrench surface means of the drill pipe member where the said wrench member can be secured thereto, and can be moved relatively axially inwardly a sufficient amount to place the teeth on the wrench member into engagement with the teeth on the outer portion of the drill head, so that the drill head can be rotated in a direction which would tend to cause loosening of the threaded tool joint and rotational torque would be transferred from the drill head through the teeth on the drill head to the teeth on the wrench member and from the wrench member to the drill pipe member.

2. Drilling apparatus according to claim 1, wherein said drilling apparatus includes a support frame for the rotary drill head and means for moving said support frame axially during the drilling operation, and the outer portion of the drill head is fixed in position axially with respect to said frame, wherein said inner portion of the drill head is generally tubular and comprises an outboard end portion which includes said threaded tool joint component and an inboard portion which is exteriorly splined, and the outer portion of the drill head includes complementary splines having spaces between them for receiving the splines of the inner portion.

5. Drilling apparatus for use with a drill pipe member having at one end thereof a threaded tool joint component connectible to a complementary threaded tool joint component carried by a rotary drive head, at its opposite end a threaded tool joint component connectible to a complementary threaded tool joint component on another drill pipe member, and between its ends an exterior wrench surface means, wrenching means comprising: a wrench including a central opening substantially larger in diameter than the drill pipe member, and a circular array of radially inwardly directed teeth at least partially surrounding said opening; and a wrench member installable onto the drill pipe member in at least a partially surrounding relationship thereto, said wrench member including an inner part engageable with the wrench surface means on the drill pipe member, and a outer portion including radially outwardly directed teeth engageable with the teeth on said wrench, with the inner part of the wrench member being sized to make a loose enough engagement with the wrench surface means so that the wrench member, when it is on said drill pipe member, is free to move circumferentially an amount at least about equal to the circumferential width of a tooth on the wrench or the wrench member, so that the teetH on said wrench member can be moved into substantial engagement with the teeth on said wrench without rotation of the drill pipe member.