US3322006A - Reversing tool for well pipes - Google Patents

Description

May 30, 1967 c. c. BROWN REVERSING TOOL FOR'WELL PIPES 5 Sheets-Sheet l Filed Dec. 7, 1964 C. C. BROWN REVERSING TOOL FOR WELL PIPI-:s

May 30, 1967 5 Sheets-Sheet. 2

Filed Dec. 7, 1964 ATTOP/Vfy May 30, 1967 c. c. BROWN 3,322,006

REVERSING TOOL FOR WELL PIPES Filed Dec. 7, 1964 5 Sheets-Sheet 5 ATTORNEY United States Patent 3,322,006 REVERSING TOOL FOR WELL PIPES Cicero C. Brown, Brown Oil Tools, Inc., P.O. Box 19236, Houston, Tex. 77024 Filed Dec. 7, 1964, Ser. No. 416,308 6 Claims. (Cl. 81-57) This invention relates to intern-al pipe wrenches and more particularly to -reversing tools for use inside pipe strings for unscrewing or tightening threaded connections between pipe string sections.

In the drilling and operation of wells, such as oil, gas, and water wells, numerous occasions arise wherein sections of pipe strings in a well bore must be unscrewed or backed-otf from the remainder of the pipe string, as in the retrieving of the free sections of a pipe string stuck in a well, or where it is necessary to tighten a loose threaded connection. As such pipe strings are normally inaccessible to conventional external wrenches, it is desirable to provide a form of internal wrench, commonly called a reversing tool for accomplishing the desired operations. Such tools are run on an operating pipe string and are designed to be operated by right-hand rotation imparted to the operating string at the surface, to transmit reverse torque to the pipe sections to be unscrewed down in the well.

Conventional reversing tools are relatively complicated and are ordinarily operable only to unscrew threaded connections and are not capable or readily adaptable for tightening threaded connections.

Generally stated, this invention contemplates a reversing tool comprising ya rotatable mandrel, a pair of longitudinally spaced two-way cam operated, pipe-gripping units disposed in the mandrel in position to engage sections of the same pipe string on opposite sides of a threaded connection between the sections, and reversing gear means mounted on the mandrel between the units and operably connected to the mandrel and both gripping units to simultfaneously transmit opposed rotational forces to the respective gripping units in response to clockwise rotation of the mandrel, and two-way cam means between the mandrel and pipe-gripping elements operable by said rotational force to cause said gripping elements to apply opposed torsional forces to the respective pipe section.

The present invention has for its primary objects the provision of an improved reversing tool which is of relatively simple and compact construction; which is eicient in operation for effecting unscrewing of threaded connections in a pipe string; and which, by simple end-for-end reversal, may be employed to tighten such threaded connections.

An important object is the provision of a reversing tool operable in response to right-hand rotation of Iau operating string to simultaneously apply oppositely directed torsional gripping forces Ito adjacent pipe sections connected by a threaded joint or coupling whereby to unscrew or tighten such threaded joints.

Another object is to provide a reversing tool in which the pipe-gripping units are constructed and arranged to torsionally grip the pipe, while permitting sufcient rel-ative longitudin-al movement of the pipe being gripped to permit the pipe sections to move apart or toward each other in the unscrewing or tightening of the connecting threaded coupling.

Other and more speciiic objects and advantages of this invention will become more readily apparent from the following detailed description when read in conjunction with the accompanying drawing which illustrates a reversing tool in accordance with one useful embodiment of this invention.

In the drawing:

FIG. 1 is a view, partly in elevation and partly in section, illustrating the reversing tool inserted in a Well pipe preparatory to -unscrewing adjacent sections thereof;

FIG. 2 is a view similar to FIG. 1 showing the tool parts at separation of the adjacent pipe sections;

FIG. 3 is a view similar to the preceding views showing the tool parts inverted for effecting tightening of a threaded joint;

FIG. 4 is an exploded perspective view of some of the reversing elements of the tool;

FIGS. 5, 8 and 9 are cross-sectional views taken along lines 5-5, 8-8 and 9 9, respectively, of FIG. l; and

FIGS. 6 and 7 are cross-sectional views taken along lines 6-6 and 7 7, respectively, of FIG, 2.

Referring to the drawing, the tool comprises a tubular mandrel, designated generally by the letter M, constructed of coaxial upper and lower sections 10 and 11, respectively, threadedly yconnected at 12. The upper end of upper section 10 is provided with an internally threaded box 13 for connection into a pipe string P employed in operating the device. Lower section 11 may also have an internally threaded box 14 for connection, where desired, of other tools, such as a landing nipple, collar or joint locators, and the like. The exterior of the mandrel sections are reduced in diameter to provide -a downwardly facing annular shoulder 15 near the upper end of mandrel section 10, and an upwardly facing annular shoulder 16 near the lower end of mandrel section 11. Mounted about the exterior of the mandrel between shoulders 15 and 16 yare the pipe gripping and reversing elements of the tool. These include upper and lower pipe-gripping units, respectively designated generally by the numerals 17 and 18, inter-connected by a torsional drive and reversing structure, designated generally by the numeral 19.

Upper gripping unit 17 comprises a generally tubular slip cage body 20 having an axial bore 21 for reception of mandrel section 10. The exterior of body 20 is reduced in diameter to provide an annular recess 22 which is dened at its lower end by the annular wall 23 having an upwardly projecting annular lip 23a mounted about its outer edge, and at its upper end by the lower end face of collar 24 seated on `the upper end of body 20 below shoulder 15 and porvided with a downwardly extending annular lip 24a about its outer edge. The upper end of collar 24 is counterbored to receive an anti-friction bearing 25 and a retainer ring 26 seated against shoulder 15 and surrounding mandrel section 10, these being arranged to permit relative rotation between' the mandrel and cage body 20.

Mounted within recess 22 surrounding body 20, is a pair of generally semi-circular pipe-gripping shoes 27 which are normally urged apart radially by means of relatively light coil springs 28 seated in suitable sockets 29 in the opposed inner ends of the shoes, as best seen in FIG. 5, the spacing between the inner ends of the shoes permitting a limited amount of independent movement of the shoes. The upper and lower edges of the shoes are provided with oppositely extending upper and lower flanges 30 and 31, respectively, which are adapted, respectively, to engage lips 24a and 23a, whereby the latter will prevent the shoes from being radially expelled from recess 22. Each of the shoes is provided centrally on its external surface with a longitudinally extending convex, generally smooth arcuate surface portion 32 whichhas a circular radius adapted to provide smooth or non-gripping engagement with the inner wall of a surrounding pipe, such as the well casing C. Surface portion 32 extends for a relatively short, angular distance about the outer periphery of the shoes. On each side of surface portion 32 the exterior of the shoes is olf-set slightly radially inwardly Vat 33 and these radially oit-set portions are provided with a plurality of parallel longitudinally extending, radially projecting teeth 34 which are normally out of contact with casing C when portion 32 is engaged with the casing wall. The teeth 34 Iare adapted, upon relative rotation between the shoes and casing C, to engage the casing and prevent further relative rotation between the shoes and casing, and to then apply a strong torsional force to the casing in response to rotational force transmitted from the cage body to the shoes. By reason of the longitudinal form of the teeth, some longitudinal slippage between the teeth and casing can occur, even though the torsional forces will prevent relative rotation between the teeth and the casing, as will appear subsequently.

To effect the relative rotation or rocking movement of the shoes, the exterior of body 20 within recess 22 is machined to provide a plurality of oppositely radially extending, longitudinally spaced lugs 35, each set of lugs on opposite sides of body 20 having registering openings 36 through which a cylindrical shaft 37 extends, the ends of the shaft being engaged by wall 23 and end face 24 to retain it in the lugs when the structure is assembled. A series of rollers 38 are mounted on shaft 37 between the several lugs 35 and constitute cam followers, the sets of the cam followers thus being mounted on diametrically opposite sides of body 20. The inner peripheries of shoes 27 on each side of the central portion thereof are provided with non-circular cam surfaces 39 which are engageable by cam followers 38 in response to relative rotation between the cage body 20 and the shoes. As best seen in FIG. 6, cam surfaces 39 are shown engaged with cooperating cams 38 to rock shoes 27 angularly relative to casing C, so as to project teeth 34 into torsional gripping engagement with the wall of casing C.

Lower gripping unit 18 is substantially identical in construction to upper gripping unit 17, except that the unit is inverted, in that collar 24 is at the lower end of the unit and is seated against shoulder 16, all of the parts heretofore described in connection with gripping unit 17 finding their identical counterparts in gripping unit 18.

The drive and reversing structure, designated generally by the numeral 19, includes a series of planetary gear elements which are arranged to transmit the desiredrtorsional forces to the gripping units. These gear elements comprise Y a drive gear formed by gear teeth which, as illustrated, are eut longitudinally in the exterior of mandrel section 10, but which, it Will be evident, may be provided by shrinking a ring gear on the exterior of the mandrel or by fabricating in any other conventional manner. Gear 45 drives through a set of planetary idler gears 46 journalled Vin a spider 52 and arranged'between upper and lower gripping units 17 and 1S, in a manner to be subsequently described. Idler gears 46 mesh with an external gear 47 mounted inside a tubular shell defining upwardly and downwardly extending annular end sections 48 and 49, respectively, which extend about the opposed ends of upper and lower bodies 20 of the gripping units. Upward extension 48 isprovided with a plurality of longitudinal splines 50 receivable in spline grooves 51 formed on the outer face of upper body 20 to form a drive connection between the external gear and upper body 20. By means of this spline connection, in conjunction with the gear connections previously described, it will be seen that when mandrel M is rotated in the right-hand or clockwise direction, idler gears 46 will rotate in the counter-clockwise direction and they, in turn, will drive external gear 47 in the counter-clockwise direction, as indicated by the arrows in FIG. 9. Lower end section 49 of the external gear is free to rotate about body 20 of the lower gripping unit.

YTo support the idler gears 46 in operative relation between drive gear 45 and external gear 47, lower body 20 is provided with an elongate extension forming spider 52 which extends upwardly toward the lower end of upper body 20 and is provided with a plurality of angularly spaced slots 53 (FIG. 4) extending downwardly from the upper end of the spider and defining at their lower ends the bottom walls 54 having cylindrical sockets 55 bored therein. Idler gears 46 are provided with upper and lower cylindrical axles or necks 56 and 57, respectively. Lower necks 57 are received in sockets 55 and are journalled in roller bearings 58 seated in sockets 55. A collar 60 is mounted on the upper end of spider '52 and is secured thereto by stud-bolts 61 countersunk in the upper end of the collar and screwed into the upper end of spider 52 between slots 53. Collar 60 is provided with cylindrical sockets 62 registering with sockets Y55 and adapted to receive upper necks 56 of the idler gears, the necks being journalled in rollerV bearings 63 seated in sockets 62. The upper end of collar 60 is provided on its inner edge with an upwardly extending annular ange 64 spaced from, and concentric with, a downwardly extending tool mounted on pipe P is'run into a well and posi- Y tioned so that the upper and lower gripping units are disposed respectively above and below a threaded coupling or joint I between upper and lower sections C1 and C2, respectively, -of casing C. The smooth surfaced mid-sections 32 of the gripping shoes will ride with a slight amount of friction on the inner wall of casing C and as operating pipe P is rotated in the right-hand or clockwise direction, this movement will be transmitted through gears 45, 46 and spider 52 to shoes 27 of the lower gripping unit, whichr will be rocked thereby in the same direction, as best seen in FIG. 7, so as to cause teeth 34 to bite into the wall of casing section C2 below coupling I. Since this section of the casing will normally be fixed in the well, further rotation of lower gripping unit 18 will be effectively stopped. At'the same time, the gear connection between main gear 45, idler gears 46 and external gear 47 will necessarily drive the latter in the counter-clockwise direction. Stoppage of rotation of lower gripping unit 18 will then cause external gear 47, acting through the spline connection formed between spline members 56 and 51, to drive body 20 of the upper gripping unit in the counter-clockwise direction,V las indicated lby the arrows on FIG. 9. This counter-clockwise movement of body 20 of the upper gripping unit will cause shoes 27 of the latter to be rockedin the counter-clockwise direction, as illustrated in FIG. 6, and will thereby apply a counter-clockwise torsional force to the upper casing portion C1 above coupling I. As this upper casing lportion C1 will be free to rotate, the continued clockwise rotation of pipe P will thus be transmitted to the upper gripping unit'and will produce continued counter-clockwise rotation of upper casing C1, while opposed torsional force is applied to lower casing section C2 until upper casingl section C1 will have been completely unscrewed from the coupling, las illustrated in FIG. 2. By

the employment of the longitudinally extending form of central positions in the respective bodies, and thereby release the tool so that it may be-withdrawn from the wellY or run down to span another lower coupling which is to be unscrewed.

In the circumstances where there may be found a threaded coupling or joint J1 as illustrated in FIG. 3, which it is desired to tighten, the reversing tool previously described is simply turned end-for-end with lower mandrel section 11 coupled to operating pipe P (FIG. 3). The tool is then run into the well to place the now reversed upper and lower gripping units on opposite sides of joint J1. Thereupon, right-hand or clockwise rotation of pipe P will produce the opposed rotations of the gripping units, that is, shoes 27 of gripping unit 18, which is now the upper gripping unit, will be rocked in a direction to apply righthand gripping torque to upper casing section C1, while opposite torsional force will be transmitted through reversing section 19 to gripping unit 17, which is now the lower gripping unit, causing the latter to apply left-hand or counter-clockwise torque to lower casing section C2. Gripping unit 18 will now serve as the back-up anchor, while clockwise rotation is transmitted directly from the mandrel to now lower gripping unit 17, thereby rotating lower casing section C2 in the counter-clockwise direction until joint J1 becomes fully made up. As only one or two turns ordinarily will be required in such cases, these turns and the small corresponding upward movement of lower casing section C2 may usually be l'attained in the lower casing section even though the latter may be secured at some lower point in the well.

It will be understood that various changes and modications may be made in the details of the illustrative embodiment within the scope of the appended claims but without departing from the spirit of this invention.

What I claim and desire to secure lby Letters Patent is:

1. A wrench insertable in a pipe string for unscrewing or tightening threaded connections between adjacent sections of the pipe string, comprising,

(a) a mandrel,

(b) means carried by the mandrel for connecting the same to a source of torsional force,

(c) longitudinally spaced substantially identical pipegripping units disposed on the mandrel in position to engage sections of a pipe string on opposite sides of a threaded connection between said sections,

(d) each of said units including pipe gripping elements operable in response to a rotational force to torsionally grip said pipe sections, and

(e) reversing gear means mounted on the mandrel between the units and operably connected to the mandrel and both gripping units,

(f) said gear means being constructed and arranged to be operable by rotation of said mandrel in the clockwise direction to simultaneously transmit opposed rotational forces to the respective gripping units. M

2. A wrench insertable in la pipe string for unscrewing threaded connections between adjacent sections of the pipe string, comprising,

(a) a mandrel,

(b) means carried -by the upper end of the mandrel for connecting the same to a source of rotational force,

(c) longitudinally spaced substantially identical upper and lower pipe-grippin g units disposed on the mandrel in position to engage sections of a pipe string on opposite sides of a threaded connection between said sections,

(d) each of said units including pipe-gripping elements movably disposed about said mandrel and cooperating two-way cam means arranged between said mandrel and said pipe-gripping elements operable in response to rotational force transmitted from said mandrel to cause said pipe-gripping elements to exert torsional force on said pipe sections,

(e) reversing gear means mounted on the mandrel between the units and operably connected to the mandrel and both gripping units,

(f) said gear means being constructed and arranged to be operable by rotation of said mandrel in the clockwise direction to simultaneously transmit clockwise rotation-al force to the lower gripping unit and counter-clockwise rotational force to the upper gripping unit whereby to exert opposed torsional forces by the respective units on the related pipe sections to unscrew the threaded connection.

3. A reversing tool insertable in a pipe string 4for unscrewing or tightening threaded connections between adjacent sections of the pipe string, comprising,

(a) mandrel,

(b) means carried by the mandrel for connecting the same to a source of rotational force,

(c) longitudinally spaced substantially identical pipegripping units disposed about the mandrel in positions to engage sections of a pipe string on opposite sides of a threaded connection between said sections,

(d) each of said units including a body, cooperating pipe-gripping elements positioned about the body and co-operating two-way cam means carried by said body and said pipe-gripping elements operable in response to relative rotation between the body and said elements to cause said pipe-gripping elements to exert torsional gripping forces on said pipe sections, and

(e) reversing gear means mounted about the mandrel between the units and operably connected to the mandrel and said bodies of both gripping units,

(f) said gear means being constructed and `arranged to be operable by rotation of said mandrel in the clockwise direction to simultaneously transmit oppositely directed rotational forces to said bodies of the respective gripping units, whereby to cause said gripping elements to exert opposed torsional forces on the respective pipe sections.

4. A reversing tool according to claim 3, wherein said reversing gear means includes a drive gear mounted about the mandrel, an external gear concentrically disposed for rotation about said drive gear, a spider secured to said body of one of said units and carrying a plurality of planetary gears drivingly connecting said drive gear to said external gear, and means forming a drive connection between said external gear and said body of the other one of said units.

5. A reversing tool insertable in a pipe string for unscrewing threaded connections between adjacent sections of the pipe string, comprising,

(a) mandrel,

(b) means carried by the upper end of the mandrel for connecting the same to a source of rotational force,

(c) longitudinally spaced substantially identical upper and lower' pipe-gripping units disposed about the mandrel in positions to engage sections of a pipe string on opposite sides of a threaded connection between said sections,

(d) each of said units including a body, cooperating pipe-gripping elements positioned about the body and co-operating two-way cam means carried by saidv body and said pipe-gripping elements operable in response to relative rotation between the body -and said elements to cause said pipe-gripping elements to exert torsional gripping forces on said pipe sections, and

(e) reversing gear means mounted about the mandrel between the units and operably connected to the mandrel and said bodies of both gripping units,

(f) said gear means being constructed and arranged to be operable by rotation of said mandrel in the clockwise direction t-o simultaneously transmit clockwise rotational force to the body of the lower gripping unit and counter-clockwise rotation to the body of said upper gripping unit whereby to cause said gripping elements to exert opposed torsional forces on the respective pipe sections in directions to cause unscrewing of said threaded connection.

6. A reversing tool yaccording to claim 5 wherein said reversing gear means includes a main drive gear mounted about the mandrel, an external gear concentrically disposed for rotation about said drive gear, a spider secured to the body of said lower gripping unit and carrying Ia plurality of planetary gears drivingly connecting said drive gear to said external gear, and means forming a drive con- 7 nection between said external gear and the body of said 1,627,842 upper gripping unit. 1,887,009 2,462,478 References Cited 2,800,043 UNITED STATESV PATENTS 5 219471521 1,110,639 9/1914 Moore 166-117.7 1,617,303 2/1927 Dougherty 166-117.7

8 Edwards 166'.117.7 Buttress 81-72 Edwards 166-117.7 Young 81-72 Tappmeyer 166 -117.7

JAMES L. JONES, JR., Primary Examiner.

Claims (1)

1. A WRENCH INSERTABLE IN A PIPE STRING FOR UNSCREWING OR TIGHTENING THREADED CONNECTIONS BETWEEN ADJACENT SECTIONS OF THE PIPE STRING, COMPRISING, (A) A MANDREL, (B) MEANS CARRIED BY THE MANDREL FOR CONNECTING THE SAME TO A SOURCE OF TORSIONAL FORCE, (C) LONGITUDINALLY SPACED SUBSTANTIALLY IDENTICAL PIPEGRIPPING UNITS DISPOSED ON THE MANDREL IN POSITION TO ENGAGE SECTIONS OF A PIPE STRING ON OPPOSITE SIDES OF A THREADED CONNECTION BETWEEN SAID SECTIONS, (D) EACH OF SAID UNITS INCLUDING PIPE GRIPPING ELEMENTS OPERABLE IN RESPONSE TO A ROTATIONAL FORCE TO TORSIONALLY GRIP SAID PIPE SECTIONS, AND (E) REVERSING GEAR MEANS MOUNTED ON THE MANDREL BETWEEN THE UNITS AND OPERABLY CONNECTED TO THE MANDREL AND BOTH GRIPPING UNITS, (F) SAID GEAR MEANS BEING CONSTRUCTED AND ARRANGED TO BE OPERABLE ROTATION OF SAID MANDREL IN THE CLOCKWISE DIRECTION TO SIMULTANEOUSLY TRANSMIT OPPOSED ROTATIONAL FORCES TO THE RESPECTIVE GRIPPING UNITS.

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