US 2320107 A
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Description (OCR text may contain errors)
May 25, 1943. s. SIVBECKERT 2,320,107
ALIGNING CONNECTION FOR DRILL COLLARS Filed July 14, 15941 L3 INVENTOR A Sieyfi'ied sfiecker,
i BY v A TT ORNE Y Patented May 25, 1943 ALIGNING CONNECTION FOR DRILL COLLARS Siegfried Speckert, Southgate, Calif., assignor to Abe g & Reinhold Co. Ltd., Vernon, Calif., a corporation of California Application July 14, 1941, Serial No. 402,364
The present invention relates particularly to an aligning connection primarily intended for the sub-connected drill collars found to be. necessary. in modern, high speed, deep hole drilling in order to add weight to the lower or bit end of the drill string, and in this way minimize the possibility of eccentric motion of the bit, for maintaining a straight hole and eliminating the hazard of twist-off.
In accordance with the best modern practise, drill collars are utilized in an assembly of desired length, usually of considerable length, sometimes reaching two hundred and fifty to three hundred feet, each collar running as high as fifty feet in length. As those collars must be carefully manufactured of specially treated material and skilled workmanship, they are costly and for this reason are ordinarily formed with female threads at both ends for connection in an assembly by means of double pin substitutes, the latter of which are commonly known as subs.
The above follows from the fact, well known in drilling practise, that the pins or male threaded parts of drill string connections constitute'the.
weakest links of the string. Hence they are commonly eliminated from expensive drill collars and left to be carried by the relatively inexpensive subs connecting the collars, so that a cracked pin necessitates only replacement of a sub. This happens quite frequently, although theoretically at least, the pin is amply strong for the taskit performs, as long as the drill collar assembly is such that its center line coincides with the center line of the hole.
In practise, however, it is found that inaccuracies in the manufacture of the less carefully formed subs, results in the deflection of one or more drill collars so that the drill collar assembly deviates from a truly straight line. This, in turn, throws severe strain upon the sub pins, since the hanging drill collars tend toward a straight line. The frequentresult isa icracked pin or pins, and when this happens it often permits alignment of the drill collar assembly and the latter then remains effective over lengthy periods of use unless the assembly parts orthe 'joint washes out. Even if the cracked pin survives, it is obvious that it remains at all times as a potential danger of a partedstring or a washed out connection.
out of true alignment, permit them totruly align Figure 7 is a detail side view with one another, without cracking the pin or pins of one or more collar connecting subs.
It is therefore the primary object of the present invention to incorporate in a connection,
involving the female threads or box ends of drill .vide an aligning connection for sub-connected drill collars by which to accomplish the elimination of the above defects in a simple, scientific manner which is mechanically correct.
'With the above in mind, the invention in its structural form at present preferred, is fully illustrated in the accompanying drawing, which forms a part of thi specification, and in which:
Figure 1 is a view, partly in elevation and partly in vertical section, showing the proposed connection between one end of a double pin, collar connecting sub and an adjacent drill collar, with the yielding means of the present invention on the pin of the sub. p
Figure 2 is a similar view showing the yielding means within the box end of the drill collar.
. Figure 3 is a detail top plan view of the ball ring of Figure 1.
Figure 4 is a detail vertical sectional view'taken diametrically through Figure 3.
Figure 5 is a detail side view of the ball ring of Figure 2.
Figure 6 is an elevation of a portion of a sub- .connected drill collar assembly, showing deflection of a drill collar by reason of a faulty sub connection, and l V of a double pin sub such as commonly used as a drill collar connection.
Referring now to the above described figures of the drawing, and particularly to Figure 7', there is shown a double pin-sub [0, the male threads of which are on pins ll projecting endwise from its opposite ends so as to engage the female threads or boxends I2'of drill collars I3 in the manner shown in said figure for the formation .of a drill collar assembly capable of adding the desired weight to the lower end of a drill string adjacent to the bit.
,Each of the collars 13, of which any number may be used in the assemblyglepending upon the desired length of the latter, and the lengths of the drill collars, is of heavy construction, and is the product of careful manufacture with the idea of eliminating any irregularities, inside or out, which would create any tendency toward eccentric movement of the bit end of the drill string.
Furthermore, since the drill collars l3 are, for the foregoing reasons, in the nature of expensive equipment, they are preferably formed with female threads or box ends I2 at both ends thereof. In this Way the box ends l2 eliminate any weakness as to the drill collars, leaving them for connection by double pin subs H], so that in case a pin is cracked it will mean replacement of only a materially less expensive sub.
In practise, the subs II! are not so carefully manufactured as to uniformly avoid faults, and
one of these faults is that not infrequently drill collars are deflected out of true axial alignment, with the result that the drill collar assembly, as seen in Figure 6, will, when rotated, developeccentricity of movement and great strain will consequently be thrown upon the sub pins H at the upper and lower endsof the deflected drill collar. In many instances this-strain results in cracking 'one or both of the pins II, and unless the assembly parts as a result of pin breakage, or a connection washes out, the assembly will often straighten itself out due to the relief afforded by the cracking of a pin or pins, and continue to function satisfactorily, although with constant danger.
To avoid the cracking of a sub pin or pins as a relief of the strain, and at the same time permit a safe relief of the strain, being the primary object and purpose of this invention, there is shown in Figure 1, by way of example, the
lower portion of one of the subs it], having its coarsely threaded depending pin I l entering the upwardly opening, and similarly threaded, box end 12 of the next lowermost drill collar 13 of a drill collar assembly. With respect to this assembly, and more particularly each drill collar l3 thereof, it will be noted that the sub H] as seen inFigure 7 is-substantially less in length and therefore more rigid and unyielding.
The sub I is cutaway, as shown, at the base of its pin H, to form an annular channel or recess, one wall of which, approximately normal to theaxis of the sub, is seen provided with a cancave surface M mating with the adjacent convex top face l5 of a ball ring l6 which sub- 5 stantially interfits the annular recess or channel of the sub.
The ball ring it is formed with a lower flat face for engagement with the end surface of the 'collar box l2 when the drill collar assembly is made up, and its outside diameter is preferably such as to coincide with that of the sub Ill. The inside diameter of the ball ring I6 is preferably such as to surround the base'of the pin H of the sub 10 in slightly spaced relation thereto, creating an allowance for limited angular shifting of the threadedly connected parts so as to relieve the pin ll of fracturing strains.
Since it is important to hold the'ball ring l6 onthe pin H in making and breakingthe connection of drill collars and subs, going in and coming out of the hole,the inner surface of the ring preferably carries a deformable, frictional, pin gripping means, as for example, an inwardly protruding resilient pin gripping band IT. This band may be suitably anchored in connection with the ring to form a part thereof, as by providing the same of dovetailed form, seated in a'similarly shaped inner annular groove of the rin g,'the band'thus being effective to=prevent the ball ring from falling into the hole, without affecting the normal function of the ball ring in use.
The above described placement of the ball ring being thus plainly set forth in its disposition around the base of the sub pin, as in Figure 1, and its general form clearly appearing in Figures 3 and 4, it remains but to observe that not only may this construction be utilized at both ends of the sub, but it may be used at one or both ends of the sub if the latter be either a double pin, pin to box, or a double box sub, since diameter than the pin carried ring l6, has its external surface annularly spaced from the internal surface of the box I2 and. has its lower face convex as at 20 to seat downwardly upon a mating concave internal surface 2| of the box, so that the ring will have a sufiicient allowance for angular shifting movement in the box to prevent fracturing strain on the pm Hi.
Also, in the form ofFigure 2, the ring 19 will have its resilient retaining band 22 on its external surface tofrictionally engage the internal surface of the box and thusavoid danger of displacement of thering after it is once inserted in position. vIt is, of course, old and well known in the art that connections between drill collars in a drill collar assembly employ taper threaded pins and boxes, and that it has been common practise to so-form theengaging threads of such connections as to permit play or relative'movement between the threadedly engaged surfaces. This has commonly been done even though it is known that where the threads are perfectly matched in the first instance when the drill collar assembly is'made up, the weight of the colla'r's and bit, and the strain of initial use in a rapidlyrota'ting drill string, quickly pulls and distorts the threads to such an extent that the play above referred to is invariably the result. It is,-therefore, common knowledge in the art that pl ay does exist in such threaded'connections'of drillcollar assemblies after actual use thereof, if not'before such use.
The present invention, it is to beunderstood, assumes the existence of the play above men- 'tioned'between the threadedly-engaged surfaces of the joints, and it will benoted that the ball joint ring proposed by the present invention is not only positioned so that it permits of relative angular movement betweenthe same along its ball surface, and the pin or box member carrying the ring, but it is also free-for permissible lateral movement along its opposite surface with respect to the other member. 'In other words the ball j0int ring,in orderto be effective for the purposes of the present invention, has merely abutting contact with both the pin and the box, and is permitted movement relative to-both pinand box, so that its function is automatically accomplished when the collar assembly is in .actualuse.
In practical use it is preferablethat the ball ring, either ring I6 or ring I9, be formed of. hardened metal to endure repeated making and breaking ofthe collar assembly in round trip ping, and avoid the disadvantage of galling, and it will be understood that while I have shown and described the invention as applied to drill collars and their connections, where its use is highly desirable on account of the described manner in which such connections are affected in practise, it will be appreciated that the ordinary tool joint between drill pipe stands is so affected to a lesser degree, and that the invention may be applied thereto for the same purpose, and to the same end, as that above outlined.
Having thus fully described the invention, what is claimed is:
l. A drill collar assembly, comprising drill collars connected in end to end relation, and a rigid ball joint member laterally shiftable in the connections between said collars and automatically laterally adjustable under tension in use, for
insuring hanging axial alignment of collars connected in non-alignment in the collar assembly.
2. A drill collar assembly, comprising drill collars, subs between and connecting the collars in end to end relation, and a rigid ball joint member laterally shiftably positioned in the connections between the subs and drill collars and automatically laterally adjustable under hanging tension in use, insuring hanging alignment of the assembly and relief of angular strain on the connec tions.
3. In an aligning connection as set forth, a taper pin, a box in which said pin is threaded, said pin and box having abutment portions, and a rigid ball joint member laterally shiftably interposed between said abutment portions, and in abutting relation only with said portions, upon which the pin and box are relatively angularly shiftable to avoid fracturing strain on the pin.
4. In an aligning connection as set forth, a taper pin and a box having engaging tool joint threads, and endwise abutment portions, and a rigid ball joint member laterally shiftable between said abutment portions, and movable relative to both portions, upon which the pin is movable to a limited extent angularly relative to the box.
5. In an aligning connection as set forth, a taper pin, a box in which said pin is threaded, the pin and box having opposing abutment portions, and a ball rigid joint ring interposed between said abutment portions, and laterally shiftable relative to both portions upon which the pin and box are relatively angularly shiftable.
6. In an aligning connection as set forth, a taper pin, a box in which said pin is threaded, the pin and box having abutment portions in opposition longitudinally thereof, and a rigid joint ring laterally shiftably disposed between said abutment portions and movable with respect to both portions, the said ring and at least one of the abutment portions having engaging concavoconvex mating surfaces.
7. In an aligning connection as set forth, a taper pin, a box in which said pin is threaded, and a hardened metal ball ring freely disposed between, and in relatively laterally movable cooperation with, adjacent portions of both the pin and box, permitting their limited relative angular movements,
8. In an aligning connectionas set forth, a box, a pin threaded in said box and having.an annular shoulder at its base opposing the box end, and provided with a concave abutment face, and a ring frictionally supported on the base portion of the pin in spaced relation annularly thereof for lateral movement relative thereto, having one face abutting the box end in laterally shiftable relation, and an opposite convex face engaging the concave face of the pin shoulder.
9. In an aligning connection as set forth, a pin, a box in which said pin is threaded, having an internal shoulder opposing the end of the pin and presenting a concave abutment face, and a ring frictionally supported in the box in spaced relation annularly thereof, having one face abutting the pin end in laterally shiftable relation, and having an opposite conve face seated on the concave face of the box shoulder.
10. In an aligning connection as set forth, a pair of threadedly connected members consisting of a pin and a box, said members having opposing abutment portions, and a hardened ball ring interposed between said abutment portions, said ring being in laterally shiftable abutting contact with one of said members and supported on, and spaced annularly from, the other of said members, and said latter member and the ringhavin relatively engaging concave-convex faces.
11. In an aligning connection as set forth, a pair of threadedly connected members consisting of a pin and a box having opposing abutment portions, a hardened metal ball ring interposed between said abutment portions in annularly spaced relation to one of said members, said latter member and the ring having relatively engaging concavo-convex faces, and a flexible, elastic band carried by said ring and protruding laterally therefrom into frictional engagement with the last mentioned member to prevent displacement of said ring when the members are disconnected.