CIRCUMFERENTIAL DISPLACEMENT SUCKER ROD TONG

Abstract

A sucker rod tong assembly for fastening together sucker rods to a rod coupling, where the assembly can include a two-stage mechanical drive mechanism. The first stage can connect an upper sucker rod to a lower sucker rod via a rod coupling. The first stage can be limited in mechanical ability to tighten the connection to a pre-set shoulder torque value. The second stage can then be hydraulically and mechanically sequenced, using a linear gear drive mechanism, to rotate a main tong pinion gear that can further rotate the sucker rod connection through a fixed circumferential displacement to a mechanical stop.

Claims

1. A method for tightening two sucker rods to a sucker rod connector after reaching the point of hand tightness, the method comprising the step of actuating a linear gear drive to move to a predetermined position, wherein the linear drive gear is in operational connection with sucker rod tongs, the movement of the linear drive gear actuating a circumferential rotational movement of the sucker rod tongs to a pre-determined position.

2. Use of a linear gear drive in a sucker rod tong assembly used in oil wells, wherein the linear gear drive is operatively connected to a sucker rod tong configured to tighten two sucker rods to a sucker rod connector from a hand-tight first position to a predetermined second position by rotating one of the two sucker rods.

3. Use according to claim 2, wherein the linear gear drive comprises a rack and pinion.

4. A sucker rod tong assembly comprising a linear drive mechanism adapted to tighten a sucker rod to a sucker rod connector from a first hand-tight position to a second predetermined position, wherein the linear drive mechanism is operatively connected to a sucker rod tong such that positive movement of the linear drive mechanism actuates rotational movement of the sucker rod tong to tighten the sucker rod to the sucker rod connector.

5. A device for use in the tightening of two sucker rods to a sucker rod coupling, the device comprising a first stage tightening mechanism and a second stage tightening mechanism, wherein the second stage tightening mechanism comprises a linear drive mechanism operatively connected to a sucker rod tong, the linear drive mechanism configured to move the sucker rod tong from a first position circumferential position to a second predetermined circumferential position.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG. 1 is an exploded side elevation view depicting two sucker rods and a rod coupling, the rod coupling shown in cross section.

[0019] FIG. 2 is a side elevation view depicting one embodiment of a CD tong assembly and a lower sucker rod (9) with rod coupling engaged with the lower back up wrench of the CD tong assembly.

[0020] FIG. 3 is a front elevation view depicting the CD tong assembly of FIG. 2.

[0021] FIG. 4 is a bottom plan view depicting the CD tong assembly of FIG. 2 in cross-section view and the hydraulic cylinder rack gear disengaged from the pinion gear.

[0022] FIG. 5 is a bottom plan view depicting the CD tong assembly of FIG. 2 with the backup wrench engaged with the lower sucker rod shown in cross section.

[0023] FIG. 6 is a top cross-sectional place view depicting the CD tong of FIG. 2 engaged with upper sucker rod connection in relation to the lower sucker rod connection.

[0024] FIG. 7 is a top cross-sectional plan view depicting the CD tong assembly of FIG. 2, wherein the tong is engaged and rotating the upper sucker rod connection in relation to the lower sucker rod connection to shoulder without the hydraulic cylinder rack gear engaged with the CD tong pinion gear.

[0025] FIG. 8 is a top cross-sectional plan view depicting the CD tong assembly of FIG. 2, wherein the tong is engaged and in rotational movement driven by the hydraulic cylinder rack gear as it is engaged with the pinion gear to a mechanical stop set and locked with a hand wheel or other mechanical adjustment.

[0026] FIG. 9 is a top perspective transparent view depicting the CD tong assembly of FIG. 2 showing the inner workings of the assembly.

[0027] FIG. 10 is a bottom perspective view depicting the CD tong assembly of FIG. 2.

DETAILED DESCRIPTION OF EMBODIMENTS

[0028] Referring to FIG. 1, upper sucker rod (8) and lower sucker rod (9) can each include threaded pin (10) that screws into coupling (11). Shoulder (12) of upper sucker rod (8) and lower sucker rod (9) can be machined to bear against axial face (13) of coupling (11). Upper sucker rod (8) and lower sucker rod (9) can be provided with a set of wrench flats (15) suitable to be engaged by sucker rod CD tong assembly (14) used for screwing together and tightening the sucker rods.

[0029] Referring to FIG. 2, CD tong assembly (14) and lower sucker rod (9) with rod coupling (11) is shown engaged with lower back up wrench (17) of the CD tong assembly (14). To tighten the threaded connection between upper sucker rod (8) and lower sucker rod (9) to a required circumferential displacement, CD tong assembly (14) can first be maneuvered to engage with mating rod flats (15) of upper sucker rod (8) and lower sucker rod (9) on either side of rod coupling (11). Then, CD tong assembly (14) can be activated to rotate the connecting threads of upper sucker rod (8) and lower sucker rod (9) into rod coupling (11) to a hand tight, shoulder circumferential start position. In some embodiments, CD tong assembly's (14) first gear hydraulic motor drive stage (25) does not have the mechanical ability to exceed the rotational forces required to exceed a hand tight connection between upper sucker rod (8) and lower sucker rod (9) and the rod coupling. Once the rotational force is achieved to a hand tight shouldered position of the sucker rod connection, a hydraulic sequence valve can automatically shift and engage second gear hydraulic cylinder linear drive stage (30) of CD tong assembly (14), which can comprise linear hydraulic cylinder (31) driven rack (32) and pinion gear assembly (33). Hydraulic cylinder driven rack (32) can then extend, rotating pinion gear assembly (33) until hydraulic cylinder driven rack (32) stops against mechanical stop (34) that can be adjusted to an exact position that is the circumferential displacement from the hand tight shouldered position for the size and grade of sucker rod of the assembly.

[0030] Referring to FIGS. 5 to 10, in some embodiments, CD tong assembly (14) can comprise rotational upper jaw (1) to engage flats (15) of upper sucker rod (8) and backup wrench (17) for engaging flats (15) of lower sucker rod (9). In some embodiments, upper jaw (1) can comprise one gripper (19) pivotally attached to gear segment (20) and outer geared ring assembly (22) by way of pins (21). Pins (21) can allow gripper (19) to pivot in and out of engagement with flats (15) of upper sucker rod (8), while gear segment (22) can render upper jaw assembly (1) rotationally relative to CD tong housing (23).

[0031] FIG. 2 shows backup wrench (17) of CD tong assembly (14) engaged from lower sucker rod (9). FIG. 3 shows CD tong assembly (14) disengaged from the sucker rods.

[0032] FIG. 4 shows a cross sectional view of CD tong assembly (14) and illustrates gear drive train (24) that can couple hydraulic motor (25) to upper jaw (1). In some embodiments, gear drive train (24) can comprise two drive gears (26) so that at least one of them remains in driving contact with gear segment (22) at all times, as gear segment (22) has a discontinuity or opening (27) for receiving and releasing upper sucker rod (8). In some embodiments, two drive gears (26) can reduce drive speed from input pinion gear (28) to input segment gear (22). In some embodiments, hydraulic motor (25) can be coupled to and turn input pinion gear (28) and rotate drive gear train (24) at a reduced speed to provide upper jaw (1) with sufficient torque to be able to screw sucker rods (8) and (9) into coupling (11) to a hand tighten shoulder torque. To disassemble or unscrew at least one sucker rod (8) or (9) from coupling (11), the rotational direction of motor (25) can be reversed.

[0033] In some embodiments, when the hydraulic pressure within the hydraulic system powering hydraulic motor (25) achieves a set fixed hydraulic pressure, a hydraulic pressure sequence valve can be activated directing hydraulic oil to hydraulic cylinder (31) activating that hydraulic cylinder (31) to move geared rack (32) to mechanical threaded stop (34) ensuring that the rod connection has achieved circumferential displacement from the hand tightened shoulder position of the connection.

[0034] CD tong assembly (14) geared rack (32) driven hydraulically by hydraulic cylinder (31) can engage with pinion gear (28) to displace the connection between upper sucker rod (8) and lower sucker rod (9) from a hand tight shouldered torque to a circumferential displacement from the shoulder tight position of the connection. The distance that the geared rack moves can correspond to an accurate circumferential displacement of the connection from the hand tight shouldered torque and can be determined by mechanical threaded stop (34) that can be adjusted manually and set by hand wheel (35). It is unique that the circumferential displacement of the connection can be determined by a fixed distance traveled to a mechanical stop by hydraulic cylinder (31) powered geared rack (32).

[0035] In some embodiments, once the connection between upper sucker rod (8) is circumferentially displaced by a predetermined distance relative to lower sucker rod (9), the linear gear drive can stop moving.

[0036] Although a few embodiments have been shown and described, it will be appreciated by those skilled in the art that various changes and modifications can be made to these embodiments without changing or departing from their scope, intent or functionality. The terms and expressions used in the preceding specification have been used herein as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding equivalents of the features shown and described or portions thereof, it being recognized that the invention is defined and limited only by the claims that follow.