automated power tong american patent free sample

This invention relates to the field of devices for rotating tubular members so as to make up or break out threaded joints between tubulars including casing, drill pipe, drill collars and tubing (herein referred to collectively as pipe or tubulars), and in particular to a power tong for the improved handling and efficient automation of such activity.

In applicant"s experience, on conventional rotary rigs, helpers, otherwise known as roughnecks, handle the lower end of the pipe when they are tripping it in or out of the hole. As used herein, the terms pipe and tubular are used interchangeably. The roughnecks also use large wrenches commonly referred to as tongs to screw or unscrew, that is make up or break out pipe. Applicant is aware that there are some other tongs that are so called power tongs, torque wrenches, or iron roughnecks which replace the conventional tongs. The use of prior art conventional tongs is illustrated in FIG. 1a. Other tongs are described in the following prior art descriptions.

In the prior art applicant is aware of U.S. Pat. No. 6,082,225 which issued Feb. 17, 1997 to Richardson for a Power Tong Wrench. Richardson describes a power tong wrench having an open slot to accommodate a range of pipe diameters capable of making and breaking pipe threads and spinning in or out the threads and in which hydraulic power is supplied with a pump disposed within a rotary assembly. The pump is powered through a non-mechanical coupling, taught to be a motor disposed outside the rotary assembly.

In the present invention the rotary hydraulic and electrical systems are powered at all times and in all rotary positions via a serpentine such as a serpentine belt drive, unlike in the Richardson patent in which they are powered only in the home position. In the present invention the pipe can thus be gripped and ungripped repeatedly in any rotary position with no dependence on stored energy and the tong according to the present invention may be more compact because of reduced hydraulic accumulator requirements for energy storage wherein hydraulic accumulators are used for energy storage only to enhance gripping speed.

Applicant is also aware of U.S. Pat. No. 5,167,173 which issued Dec. 1, 1992 to Pietras for a Tong. Pietras describes that tongs are used in the drilling industry for gripping and rotating pipes, Pietras stating that generally pipes are gripped between one or more passive jaws and one or more active jaws which are urged against the pipe. He states that normally the radial position of the jaws is fixed and consequently these jaws and/or their jaw holders must be changed to accommodate pipes of different diameters.

Applicant is further aware of United States Published patent application entitled Power Tong, which was published Apr. 5, 2007 under Publication No. US 2007/0074606 for the application of Halse. Halse discloses a power tong which includes a drive ring and at least one clamping device with the clamping devices arranged to grip a pipe string. A driving mechanism is provided for rotation of the clamping device about the longitudinal axis of the pipe string. The clamping device communicates with a fluid supply via a swivel ring that encircles the drive ring of the driving mechanism. Thus Halse provides for three hundred sixty degree continuous rotation combining a spinner with a torque tong. The Halse power tong does not include a radial opening, the tong having a swivel coupling surrounding the tong for transferring pressurized fluid from an external source to the tong when the tong rotates about the axis of the pipe. Halse states that having a radial opening in a power tong complicates the design of the power tong and weakens the structure surrounding the pipe considerably, stating that as a result, the structure must be up-rated in order to accommodate the relatively large forces being transferred between the power tong and the pipe string. Halse further opines that a relatively complicated mechanical device is required to close the radial opening when the power tong is in use, and in many cases also to transfer forces between the sides of the opening. The Halse tong is not desirable for drilling operations because there is no throat opening to allow the tong to be positioned around the pipe at the operator"s discretion. The pipe must always pass through the tong.

The power tong according to the present invention continuously rotates tubulars for spinning and torquing threaded connections. Continuous rotation is achieved through a rotating jaw (also referred to as a rotor) that has grippers that grip the tubular. Hydraulic and electrical power necessary for actuating the grippers is generated on board the rotor since the continuous rotation does not allow for either hydraulic or electrical external connections. A serpentine member such as a serpentine drive belt system turns the motors of an on-board hydraulic power unit and electric generators which may be AC or DC generators, to supply the grippers with the necessary hydraulic and electrical power.

The present invention includes a rotor rotably mounted in or on a rigid structural framework or stator frame. A main drive drives the rotor. The rotor may be supported and held in position by the use of opposed helical pinions/gears which support the rotor vertically and guide bushings which locate it laterally and support it vertically when the torque is low. The grippers, which may be actuated by hydraulic gripper cylinders, maybe held in position by links and guide bushings that can withstand the torque parameters of the tong. The gripper cylinders may be moved in a range of travel by an eccentric. This provides for a tong that can accommodate a large range of pipe diameters (3.5 inch drillpipe to 9-⅝ inch casing or larger). A centralizing linkage ensures that the pipe is gripped concentricly with the tong axis of rotation. The tong does not require a mechanical device to close the radial opening. The on-board power source and rotary control system allow the present invention to have fully independently activated and controlled rotary gripping of the tubular. It is capable of high torque for making and breaking and high speed for spinning, all within one mechanism. One embodiment of the present invention also overcomes the limitation of the spinning wrench engaging the stem area of the drillpipe which over time will cause fatigue in the stem area as the spinning and torquing according to the present invention is accomplished with the same jaw that engages the pipe on the tool joint. The throat of the jaws according to the present invention has an opening of sufficient diameter to accept a tubular. The throat cooperates with the opening to allow the power tong to be selectively positioned around the pipe at the operators" discretion.

FIGS. 18 and 19 are in diagrammatic plan view, a further exemplary embodiment of the nested transmission of the tong, showing the use, by way of example, of two stator sprockets, at least one of which is driven, having a serpentine member therearound and reaved over a pair of rotor sprockets on the throated rotor, the pair of rotor sprockets having a synchronizer therearound, the rotor sprockets driving a coupling mechanism coupling the power transfer from the serpentine member to gripper actuators on the rotor which articulate grippers at the rotor axis of rotation.

FIG. 19ais a partially cut-away section view along line 19 a-19 ain FIG. 19 showing one rotor (satellite) sprocket driving, by way of example, a pump and/or generator part of the power or energy transfer coupling between the serpentine member and the gripper actuators.

As seen in FIGS. 1 and 2, the power tong 6 may include three main sections mounted on a common axis A; namely a main drive section, a rotor, and a back-up jaw. Each of the sections contains actuators, as better described below. The main drive section 10 which provides at least part of a rigid stationary framework or stator frame is located above the rotor 22. The backup jaw 48, located below rotor 22, may also provide part of the stator frame. The rotor 22 rotates relative to the main drive and back-up jaw. Both the rotor and backup jaw clamp their respective sections of pipe. The rotor 22 is rotated by the main drive section 10 independently of the main drive section and backup jaw in the sense that the rotor 22 is self-contained, having on-board hydraulic and electric power generators to power on-board radial clamps or grippers (collectively herein referred to as grippers), and an on-board serpentine secondary power transmission, all configured to allow the insertion and removal of a pipe through a jaw opening from or into the center of the jaw, so that the pipe, when in the center of the jaw may be clamped, torqued, and spun about axis A of rotation of the rotor 22 while the other, oppositely disposed section of pipe is held clamped in the center of the back-up jaw 48.

As shown in FIGS. 1, 2 and 3 rotor 22 is housed within drive section 10, although this is not intended to be limiting as the rotor may be mounted so as not to be housed within the drive section and still work. The rotor 22 is cylindrical in shape and has an opening slot, which although illustrated as linear may be linear or non-linear, having a throat 38 for passing of a tubular along the slot thereby allowing the tong axis of rotation A to be selectively positioned concentric with pipe 8, provided the rotor 22 is rotated such that its throat 38 is aligned with the front openings 28 and 29 of the main drive section and back-up jaw, respectively. Center 40 of the yoke formed by the jaw and slot corresponds with axis A. The rotary jaw 22 has three gripper cylinders 44 a, 44 b, and 44 carranged radially, with approximately equal angular spacing around axis A, mounted between the two parallel horizontal planes containing rotor gears 30 aand 30 b. The number of gripper actuators, such as gripper cylinders 44 a-44 c, and associated grips or grippers may be more or less in number, so long as a tubular joint may be gripped or clamped at center opening 40.

A serpentine member such as serpentine drive belt 20 is driven by two serpentine drive motors 18, which may for example be hydraulic or electric motors. The serpentine member is mounted around so as to engage stator sprockets mounted on the stator frame. For example the stator sprockets may include drive sprockets 26 awhich are driven by serpentine drive belt 20 to collectively provide a secondary drive powering the grippers on the rotor 22. Drive sprockets 26 arotate serpentine drive belt 20 about idler sprockets 26 mounted to drive section 10. And the serpentine drive belt 20 also engages about rotor sprockets 32 a-32 fmounted on the rotor 22 as better described below. The rotor sprockets 32 aand 32 bmay be two generator drive sprockets. The rotor sprockets 32 cand 32 dmay be two pump drive sprockets. Rotor sprockets 32 eand 32 fmay be two idler sprockets. In the illustrated embodiment, which is not intended to be limiting as other embodiments discussed below would also work, the generator drive sprockets, that is, rotor sprockets 32 aand 32 b, transmit rotary power to generators 34. The pump drive sprockets, that is, rotor sprockets 32 cand 32 d, transmit rotary power to hydraulic pumps 36 by the action of serpentine drive belt 20 engaging the upper groove of rotor sprockets 32 a, 32 b, 32 cand 32 d. A synchronization belt, 28 a, connects the lower portions of the rotor sprockets 32 a-32 f. Thus as the rotor 22 rotates on axis of rotation A, even though serpentine drive belt 20 cannot extend across the throat 38 because such a blockage would restrict selective positioning of the pipe 8 along the slot into the tong, serpentine drive belt 20 wraps in a C-shape around the rotor sprockets 32 a-32 f. Serpentine drive belt 20, driven by drive sprockets 26 a, runs on pulleys 26, and on idler sprockets 26 band 26 cmounted to, so as depend downwardly from, main drive section 10. The extent of the C-shape of serpentine drive belt 20 provides for continual contact between serpentine drive belt 20 and, in this embodiment which is not intended to be limiting, a minimum of three of the rotor sprockets 32 a-32 fas the rotor rotates relative to the main drive section 10. The synchronization belt 28 amounted on the rotor maintains rotation of the individual rotor sprockets as they pass through the serpentine gap 29 seen in FIG. 4, that is, the opening between sprockets 26 band 26 c. Synchronization belt 28 asynchronizes the speed and phase of the rotation of each of the rotor sprockets 32 a-32 fto allow each of them in turn to re-engage the serpentine drive belt 20 after they are rotated across the serpentine gap 29 by the action of the rotor rotating relative to the main drive.

During operation of tong 6 the secondary drive (drive motors 18) and serpentine drive belt 20 run continuously to deliver power to the on-board pumps and generators by means of the rotor sprockets 32 a-32 d. Rotation of the rotor 22 by the operation of the primary drive acting on the pinions 56 and rotor gears 30 aand 30 bdoes not substantially affect the powering of the on-board accessories (pumps and generators) because drive belt 20 is run at substantially an order of magnitude greater speed than the speed of rotation of rotor 22. The rotation of the rotor only adds or subtracts a small amount of speed to the rotation of the rotor sprockets.

Upper rotor gear 30 aand lower rotor gear 30 bare parallel and vertically spaced apart so as to carry therebetween hydraulic pumps 36, generators 34, the rotor hydraulic system, rotor jaw electrical controls and the array of three radially disposed hydraulic gripper cylinders 44 a, 44 b, and 44 c, all of which are mounted between the upper and lower rotor gears 30 aand 30 bfor rotation as part of rotor 22 without the requirement of external power lines or hydraulic lines or the like. Thus all of these actuating accessories, which are not intended to be limiting, may be carried in the rotor 22 and powered via a nested transmission, nested in the sense that the C-shaped synchronization drive loop mounted on the rotor, exemplified by synchronization belt 28 a, is nested within so as to cooperate with the C-shaped serpentine drive loop mounted to the main drive, exemplified by serpentine drive belt 20.

Thus as used herein, a serpentine belt, such as the serpentine belt 20, driving a plurality of stator and rotor sprockets (as herein below defined), and as in the various forms of the stator and rotor sprockets found illustrated in all the figures herein, are herein referred to generically as a form of nested transmission. The nested transmission transfers power from the fixed stage to the rotational stage in a continuous fashion as, sequentially, one element after another of the rotational drive elements on the rotating stage are rotated through and across throat 38 and gap 29 allowing selective access of the tubular 8 to the center opening 40 of the stage.

For proper operation of the tong, it is desirable that the gripper actuators such as gripper cylinders 44 a-44 cclamp the tubular 8 substantially at, that is, at or near the rotational center axis of the tong. It can be readily seen that gripping the tubular 8 with a significant offset from the center axis would result in wobble or runout of the tubular when spinning in or out and could result in thread damage, excessive vibration, damage to the machine and inaccurate torque application.

It will be appreciated that the inboard ends of side gripper cylinders 44 aand 44 bmove in an arc as the gripper cylinders are extended or retracted. For the side gripper cylinders 44 aand 44 b, the geometry of reaction links 44 eis optimized to minimize deviation from the nominal gripper cylinder radial axis over the gripping diameter range to angles typically less than one degree. The gripper cylinders 44 aand 44 bwill however swing significantly from the nominal gripper cylinder radial axis, in the order of five degrees, when they fully retract to clear the throat 38. It is an advantage of the link design that it requires less stroke to clear the throat 38 due to the swing associated with the arc of reaction links 44 e, which ultimately allows a more compact rotor and hence a more compact tong. That is, the combination of the swing in direction C with the retracting stroke in direction D results in less of a stroke length required to clear throat 38 than merely using a retraction stroke without swing. The amount of swing is governed by the radius of arc E associated with rotation of the reaction links 44 eand the length of the required stroke in direction D.

The back-up jaw section 24 as shown in FIGS. 5, 5 a, 6 and 8 is typically mounted to a tong positioning system capable of holding the tong assembly level and enabling vertical and horizontal positioning travel. The tong may be pedestal-mounted on the rig floor, mast-mounted, track-mounted on the rig floor or free hanging from the mast structure. It may also be mounted at an angle for slant drilling application or with the pipe axis horizontal.

In the preferred embodiment, as seen in FIG. 10, the rotor hydraulic system 53 is a dual (high/low) pressure system or infinitely variable pressure system which produces high pressures (in the order of 10,000 psi) necessary for adequately gripping large and heavy-duty tubulars and for applying make-up or break-out torque, and lower pressures (2500 psi or less) to avoid crushing smaller or lighter-duty tubulars. Hydraulic pumps 36, rotationally driven as described above, are fixed-displacement, gear or variable displacement piston pumps. In the idle state, hydraulic pumps 36 charge one or more gas-filled accumulators 55 mounted in or on rotor 22 to store energy to enable rapid extension of the gripper cylinders 44 a-44 c. In this way, very fast gripping speeds may be achieved while keeping the power transmitted by the serpentine drive belt 20 drive low. That is, although the power supplied via the serpentine drive belt is small, the rotor hydraulic system must be able to intermittently supply a relatively large flowrate at low pressure for rapid advance of the gripper cylinders until they contact the tubular and also supply a low flowrate at very high pressure, in the order of 10,000 psi, to adequately grip the tubular for torquing operations.

In the schematic of the preferred rotor hydraulic system 53 of FIG. 10, system 53 has one or two gear or piston pumps 36 of relatively small capacity, within the power limitations of the serpentine drive belt. When there is no gripping demand, the pumps charge one or more gas-filled accumulators 55 to store energy for intermittent peak demands. The accumulators are optional, for the benefit of advance speed. The system is workable without accumulators provided the pumps are variable displacement. A load-sensing circuit with or without regenerative advance may also be used as would be understood by someone skilled in the art. A directional control valve 63 directs hydraulic pressure to the gripper cylinders. The directional control valve is solenoid-actuated with the solenoids controlled by the rotor control system. There are two flow paths from the directional control valve 63 to the extend side of the gripper cylinders. The first is the rapid-advance flow path which directs a large flowrate, in the order of thirty-five gallons per minute, from the pump(s) 36 and accumulator(s) 55 to the gripper cylinders at relatively low pressure, in the order of 2500 psi, for rapid extension of the gripper cylinders until they contact the tubular 8. The second is the high-pressure path in which pressure is regulated by a proportional pressure control valve 64 which is controlled by the rotary jaw control system of FIG. 11. The regulated pressure is supplied to an intensifier 65 which boosts the pressure by a factor in the order of 4:1 to supply high pressure, in the order of 10,000 psi, to the gripper cylinders. A check valve 66 prevents the high pressure fluid from flowing back into the rapid-advance low pressure flow path. The directional control valve 63 can also be solenoid actuated to direct fluid to the rod side of the gripper cylinders for retraction.

The use of high grip pressures, in the order of 10,000 psi, allows the use of compact gripper cylinders which results in a compact tong. By using the intensifier 65 to build the high grip pressure, no high pressure control valves are required.

It can be seen that in spite of the small input power, the hydraulic system can intermittently supply large flowrates for rapid grip cylinder advance and high pressures for high-torque operations. The system can regulate the grip pressure, adapting to the applied torque, for optimum gripping performance.

The rotor control system seen in FIG. 11 activates and de-activates the gripper cylinders at the operator"s discretion, regulates grip pressure and monitors system function without any power supply or control wires from or to the fixed part of the tong, because the rotor is fully rotatable and the open throat of the yoke precludes the use of any slip rings which are commonly used to transmit electrical power and control signals to a rotating element.

As seen in FIG. 11, one or two generators 34 are driven by the serpentine belt drive 20. They supply power, preferably 24 volts DC, to a programmable logic controller (PLC) 70, a radio communication link 71 and a number of sensors 73.

The radio communication link 71, which may advantageously be a Bluetooth™ device, communicates wirelessly with a similar radio communication link 72 mounted on the stationary section of the tong. The two radio communication links, 71 and 72, act as a wireless communication bridge between the main tong control system 74 and the rotor PLC 70.

The rotor PLC 70, as directed by the main tong control PLC 74, controls the output solenoids on directional control valve 63 to extend and retract the gripper cylinders 44 a-44 cand the proportional pressure control valve 64 to control the grip pressure. It also receives feedback from sensors 73 on the rotor for such parameters as (possibly including but not limited to) grip pressure, hydraulic pump pressures, grip position and hydraulic oil temperature.

When breaking out (unscrewing) drilling tubulars, it is often difficult to identify the axial location of the split where the two tool joints meet. It is imperative that the tong be positioned such that the split is located in the axial gap between the rotor grippers and the back-up jaw grippers. If either the rotor or the backup jaw grips across the split, the tool joint and the tong may be damaged and time will be wasted because the connection will not break out.

As shown in FIGS. 15 and 16, the actual face seam 200 between the mating connection shoulder faces 201 is only marginally visible when the connection is made up and it may be further obscured by drilling fluid. There is typically a shoulder bevel 202 adjacent to each shoulder face 201. The shoulder bevel 202 is typically machined at a 45 degree angle and has a radial dimension typically 2 to 6 mm. The two adjoining shoulder bevels 202 combine to form a connection split bevel V-groove 203. The connection split bevel V-groove 203 is usually sufficiently visible to identify the split axial location for placement of manual tongs in conventional drilling operations. But for a mechanized tong with its operator positioned several feet away from the pipe, it may be difficult to see. Furthermore, the tong may obscure the operator"s direct view of the split location. Time will be wasted in identifying the split location, traveling to it and verifying that the split is correctly located in the axial gap between the rotary and back-up jaws.

For automated pipe-handling operations, it is important for the machine to identify and travel to the correct axial location of the split without control intervention by the operator.

It can be seen that a reliable automated system to detect the location of the connection split would improve speed and efficiency of a mechanized tong and is mandatory for fully-automated tong operations.

A tandem configuration may be employed. That is, the optical tubular caliper can be accomplished with a pair of single point beam sensors positioned approximately 180 degrees apart, with each beam projected radially inward toward the tubular at the same elevation. Each sensor measures the radial distance to the pipe surface. The control system computes the sum of these distances. The difference between a fixed offset value and the computed sum represents the diameter of the tubular, approximately independent of the position of the tubular in the opening. The system can quickly and accurately measure the diameter of any tubular passing through the single point beams and transmit the diameter measurement to the tong control system. Furthermore, as the tong travels axially along the pipe, the tong control system can relate a series of such diameter measurements to the corresponding tong elevations as measured via the control system instrumentation described elsewhere. A diameter profile along the length can thus be created, effectively a virtual diameter versus axial position plot. The control system can compare this diameter profile to the known characteristic of the connection split bevel V-groove 203. When such a profile match is identified, the connection split is located and the corresponding tong elevation is recorded. The tong then travels the contact axial offset distance between the light band 705 axial mounting position and the desired split position between the rotary and back-up jaw grippers.

The control system is programmed to tune out irrelevant variations in the measured outside diameter, such as at the tool joint upset steps. It will also filter out diametral noise associated with surface irregularities such as hardbanding, tong marks or wear grooves.

As mentioned above, the power tong according to the present invention may be mounted in many ways on the drilling rig structure, or it may also be free-hanging from a cable. The mounting method ideally allows the tong to be accurately positioned around the tubular 8 at a large range of elevations, retracts a substantial distance from well center for clearance for other well operations, parks in a small area to minimize space usage on the drilling rig floor, keeps the tong level and allows the tong to be positioned to work at multiple locations such as the mousehole which may not be in the same plane as well center and the tong park location. The mounting system could be capable of rapid movement between working and idle positions but with smooth, stable motions. It should allow the operator to command horizontal or vertical movements or a combination.

Numerous tong or wrench mounting mechanisms exist in the industry. Most are Cartesian (horizontal/vertical) manipulators employing tracks, slides or parallelogram linkages for each motion axis. These mechanisms are simple to control because they directly actuate on the horizontal and vertical axes but they typically have a small range of motion which limits tong functionality and restricts mounting location on the drill floor. They have a large parked footprint which consumes scarce rig floor space and interferes with other well operations. And they have little or no capability to react torque applied to the tong or wrench by a top drive in the rig.

Thus in one preferred embodiment, a tong is preferably mounted on a manipulator 99 as shown in FIGS. 12aand 12b. A slewing base 100 is mounted to the drilling rig floor. A hydraulic slewing motor 101, via a gear reduction, can turn the slewing base up to three hundred and sixty degrees about the vertical axis. The internal bearings of the slewing base can support the weight and overturning moments of the manipulator structure and the tong. Slewing motor 101 may alternatively be electric, pneumatic or manually actuated.

The tong is pivotally mounted at the end of boom 103. The angle of the tong relative to boom 103 is controlled by linear actuator(s) 106. The inclination of the tong is monitored by angle sensor 109.

Various possible tong positions are selectively positioned between the extended operating position illustrated in FIG. 12aand the parked position of FIG. 12b. It can be seen that the manipulator 99 provides a large range of motion but can park the tong 6 with a small footprint.

The booms have significant lateral and torsional stiffness. This is advantageous over prior systems because the structure can react torque applied to the tong by a top drive in the rig, such as for back-up of drilling connection make-up. The tong can also apply torque to make up a bit restrained in the rig"s rotary table.

Manipulator 99 may be fully functional with manual controls for each of the four output actuators (slewing motor 101 and linear actuators 104, 105 and 106). However, it preferably has a control system as described below in which horizontal and vertical rates of tong travel are controlled in direct proportion to horizontal and vertical velocity commands by the operator and the tong is automatically kept level. The control system may also include the capability of optimized travel, including acceleration and deceleration control, to pre-defined locations.

The tong"s vertical and radial positions (relative to the slewing base) at any time are computed by the programmable logic control (PLC) 112 geometric constants and the boom 102 and 103 angles measured by angle sensors 107 and 108. The slewing orientation is measured preferably by an encoder 110 on the slewing drive. The tong"s three-dimensional position is therefore monitored at all times.

The preferred operators control console has a single 3-axis joystick 111 for control of the manipulator. The x-axis of joystick 111 controls the horizontal motions of the tong, the y-axis of the joystick 111 controls the vertical motions of the tong and the z-axis (handle twist) of the joystick controls the slewing motions of the assembly. The joystick commands may be discrete ON/OFF but are preferably analog/proportional on the x and y axes for finer control.

Horizontal motion of the tong requires movement of both boom 102 and boom 103, accomplished via linear actuators 104 and 105. The required output velocity signals to each of linear actuators 104 and 105 are computed in the PLC 112 in order to achieve the desired horizontal command velocity from the x-axis of joystick 111.

Similarly, vertical motion of the tong requires movement of both boom 102 and boom 103, accomplished via linear actuators 104 and 105. The required output velocity signals to each of linear actuators 104 and 105 are computed in the PLC 112 in order to achieve the desired vertical command velocity from the y-axis of joystick 111.

The control system may also have capability for automated travel to pre-defined locations such as well center, mousehole and parked position. When the operator commands automated travel to a desired pre-defined target location, the control system control acceleration, travel velocity, deceleration and landing speed for both horizontal and vertical axes to achieve optimum travel to the target, with minimum elapsed time and smooth, controlled motion.

In particular, in FIG. 18, serpentine drive belt 20′ is driven by at least one serpentine drive motor which may for example be at least one hydraulic motor. The serpentine drive motor drives at least one drive sprocket 26 a′ which, as before, provide a secondary drive via a plurality of rotor or satellite sprockets 32′ on rotor 22, and also drives a synchronizer between sprockets 32′ and a coupling such as pumps or generators, or a mechanical mechanism powering gripper actuators and corresponding grippers 44′, or directly acting on grippers 44′, on the rotor 22. As illustrated by way of example, a first drive stator sprocket 26 a′ rotates serpentine drive belt 20′ about a second stator sprocket which may be a second drive sprocket 26 a′ or an idler sprocket 26′ mounted to drive section 10. A tensioner 27 such as a tensioning idler sprocket, which may be considered a third stator sprocket, may be mounted to frame 60 so as to be resiliently biased against serpentine drive belt 20′ to tension the drive belt. A pair of satellite or rotor sprockets 32′ are mounted on the rotor 22. As seen in FIG. 18, the first and second stator sprockets are mounted on substantially opposite sides of the rotor. As the term is used herein, the first and second stator sprockets are arrayed substantially around the rotor. Third, fourth, etc stator sprockets would thus not have to be on one side or the other of the rotor, but would form part of the array of stator sprockets arrayed substantially around the rotor.

The rotor sprockets 32′ drive for example one or more on-board generators and/or one or more on-board hydraulic pumps (not shown in FIGS. 18 and 19). Synchronization belt 28 a′ may connect the lower or upper portions of the rotor sprockets 32′, with the serpentine drive belt 20′ then connecting the upper or lower portions of the rotor sprockets 32′ respectively. Thus as rotor 22 rotates about axis of rotation A even though serpentine drive belt 20′ cannot extend across the opening throat 38 because such a blockage would restrict selective positioning of the pipe 8 along the slot into the tong, serpentine drive belt 20′ wraps around or reaves so as to remain at all times in contact with at least one of rotor sprockets 32′. Drive sprockets 26 a′ are mounted to, so as to for example depend downwardly from, main drive section 10. As seen in FIG. 18a, the deflection of serpentine drive belt 20′ by the rotation of rotor sprockets 32′ provides for continual contact between serpentine drive belt 20′ and a minimum of one of the rotor sprockets as the rotor 22 rotates relative to the main drive section 10, wherein the deflection of serpentine drive belt 20′ tensions the portion of drive belt 20′ where it contacts tensioner 27. Upon return of the rotor sprockets to the position of FIG. 18, tensioner 27 takes up the slack in the drive belt 20′.

As seen in FIG. 19a, rotor 22, the rotor sprockets 32′, and one or more energy coupling 45 may be mounted within a rotary jaw frame 47 on, for example, bushings 49. Energy couplings 45 couple the energy being transmitted from the serpentine to the rotor sprockets 32′, and couples the energy to the grippers 44′ or gripper actuators (which in turn actuate the grippers). As stated above, energy couplings 45 may include pumps, generators, or mechanical drives such as direct mechanical linkages, but may also include the use of energy storage such as, without intending to be limiting, gas accumulators, batteries, capacitors, flywheels, which may then power actuation of the grippers when needed.

March 17, 1970 J. H. WILSON AUTOMATED PIPE TONGS l9 Sheets-Sheet 5 Filed May 1, 1967 VIIIIII Rm 5 .m a. m :W m /m mw u H hw m. 7 m p uildli|||J||1||i|||||||J |||J" W m w M 8 y 1 0 mm mm 00 mm March 17, 1970 J. H. WILSON AUTOMATED PIPE I"ONGS 19 Sheets-Sheet 4 Filed May 1, 1967 E m mF 1176 19/9/67 W/LFU/V INVENTOR.

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US. Cl. 81-5734 Claims ABSTRACT OF THE DISCLOSURE Automated pipe tongs for making up or breaking out drill stem or pipe, such as used in conjunction with a drilling rig, which tongs are moved into and away from operating position on a wheeled carrier. The various operations of tongs are actuated by fluid cylinders, which fluid cylinders are programmed by a rotary cam programming control mechanism, to cause sequential action of certain cylinders, both for the opening and for closing the tongs and for moving the handle of one of the tongs arcuately to make up or break out drill stem or pipe. Two or more cams may be programmed to operate simultaneously, with the same operations being repeated each time the programming mechanism makes one complete cycle. The present programming device is so constructed as to stop when one cycle is completed. Provisions are made for stopping the programming mechanism at any point within the cycle and for manually operating valves to perform any phase of the operation. Further valves are provided to selectively render any portion of the operation inoperative. Further provisions are made to enable the entire programmed cam shaft to be removed and another programmed cam shaft installed to perform diflerent operations.

This invention relates to pipe tongs to be used for gripping pipe to enable pipe to be screwed together or unscrewed, and more particularly to power actuated pipe tongs which may be remotely controlled so the individual operating the tongs is relieved of openin and closing the tongs, of engaging the tongs on the pipe and of removing the tongs therefrom, as well as of moving the lever of the tongs arcuately about the axis of the pipe when the tongs are engaged on the pipe.

Various tongs have been provided heretofore which are operated both manually and by power, however, for the most part, these tongs had to be manually controlled to engage the pipe and manually swung out of engagement when the pipe was sufiiciently tightened.

The present tongs are so constructed that a single operator may operate both the tongs to enable automatic or mechanical engagement thereof with the pipe, from a non-operating position to an operating position, and then, after the tongs are in position to engage the pipe, power is used to close the tongs in gripping relation around the pipe. Furthermore, the apparatus for handling the tongs is actuated by fluid power, which rotates the pipe in either direction as desired, while the back-up tong is maintained in engaged gripping relation with a complementary joint of pipe so as to enable the entire work to be performed by remote control, and without danger to the workmen, as has been the case heretofore, in most instances, in the use of power actuated tongs.

The present tongs are used primarily in combination With a derrick, mast or the like, however, they are subject to adaptation to any phase of screwing together or unscrewing pipe, merely by changing the mounting to accommodate the particular pipe screwing up or unscrewing job to be done. The present tong is primarily used with drill pipe in the drilling of oil wells, which pipe consists of threaded joints, to enable the coupling of lengths of pipe together in the form of a drill stem, which may extend several hundred or several thousand feet into the earth strata to perform the operation of drilling an oil well by the rotary drilling method. In performing this drilling operation, it is desirable to have all pipe joints tightened securely and accurately, but not tightened to such extent as to cause the threads to gall or to strip.

An object of this invention is to provide power actuated tongs which may be swung into place around axially aligned lengths of pipe to enable the making up or breaking out of the threaded joints connecting lengths of pipe in end-to-end relation.

Another object of this invention is to provide a power actuated tong in which all control operations may be performed from a remote station, to enable the tongs to be guided onto the pipe, so as to surround lengths of axially aligned pipe to screw the pipe together, or to unscrew the lengths of pipe without manual assistance from the operator.

Still another object of the invention is to provide a power actuated tong for gripping lengths of pipe to be screwed together, wherein a cam and lever, operated under fluid pressure, closes the jaws of the tongs around the pipe in gripping relation to give a mechanical advantage.

Still another object of the invention is to provide a side opening tong which may be moved onto or off of a pipe from a side thereof without the necessity of having to draw the pipe through the tong.

Still another object of the invention is to provide a suspension system for a pair of tongs, whereby they can be moved into or out of engagement with a pair of axially aligned lengths of pipe in the same path each time the tongs are positioned thereon, thereby making it unnecessary for manual guidance of the tongs into the correct position.

Still another object of the invention is to provide a power actuated tong which may be readily regulated to take care of worn pipe or pipe of diflerent diameters.

Still a further object of the invention is to provide tong adjustment means to enable the attachment of the tongs to the pipe in such manner as to swing the tongs into place around axially aligned lengths of pipe in the same relation each time.

Still another object of the invention is to provide fluid power actuated cylinder means to rotate at least one of the tongs through an arcuate travel each time the fluid actuated cylinder plunger is reciprocated.

Still a further object of the invention is to provide a tong mounting system to enable the tongs to be moved into engagement with a pair of axially aligned lengths of pipe and be moved out of engagement with the pipe and out of the work area when the screwing or unscrewing operation has been performed.

A power tong (1) device, in which the power tong (1) includes two housing halves (2), pivotable relative to each other, the housing halves (2) being arranged to be pivoted between a closed, active position and an open, inactive position, and in which a radially divided drive ring (6, 8), which is provided with hydraulically activated clamping dies (14) directed towards the centre axis (10) of the power tong (1), is placed in the housing halves, the drive ring (6, 8) being supported and connected to a driving motor (12) for the rotation of the drive ring (6, 8) about said axis (10), the drive ring (6, 8) being provided with at least one locking means (16) which is arranged to interconnect the parts of the drive ring (6, 8) in a releasable manner.

This invention relates to a power tong. More particularly it relates to a power tong, in which the power tong comprises two housing halves pivotable relative to each other, the housing halves being arranged to be pivoted between a closed, active position and an open, inactive position. A radially divided drive ring provided with hydraulically activated clamping dies directed towards the centre of the power tong is placed in the housing halves, the drive ring being supported and connected to a drive for the rotation of the drive ring about said centre axis. The drive ring is provided with at least one bayonet catch, which is arranged to connect the parts of the drive ring in a releasable manner.

In connection with drilling operations in the ground, in which joinable drill pipes are used, for example in the recovery of petroleum, mechanized pipe tongs in the form of power tongs are well known and extensively used.

Power tongs of this kind normally include hydraulically or mechanically activated grippers or clamping dies which are arranged to clamp a pipe grippingly.

It is common that power tongs either are provided with a radial opening or can be opened, so that the power tong can be moved in a radial direction onto and away from the pipe.

Due to the relatively great clamping forces that are necessary when pipes are being connected, open power tongs are often relatively heavy because they have to be sized to be able to absorb said forces. Closed power tongs, in which the clamping forces can be absorbed by a closed ring, are often relatively light, but it has turned out to be difficult to provide a closing mechanism for the power tong, which is both strong enough and which exhibits the necessary reliability.

A power tong according to the invention includes two housing halves, pivotable relative to each other, the housing halves being arranged, preferably hydraulically, to be pivoted between a closed, active position and an open, inactive position. A radially divided drive ring, which is provided with hydraulically activated clamping dies directed towards the centre axis of the power tong, is placed in the housing halves, the drive ring being supported and connected to at least one driving motor for the rotation of the drive ring about the centre axis. The drive ring is provided with at least one locking means, typically in the form of a bayonet catch which is arranged to join the drive ring together in a releasable manner.

In the drawings the reference numeral 1 denotes a power tong, s which includes two housing halves 2, movable relative to each other and connected, jointly liftable and lowerable, to a support 4 in a manner known per se.

A piston 38 extending in a cylinder 40 in the extension of 2D the piston recess 36, is arranged to move the index pin 32 to its second position, in which the index pin 32 is disengaged from the piston recess 36 and thereby is free to rotate about the centre axis 10 of the power tong together with the drive ring 6, 8.

a radially divided drive ring having a first and a second drive ring part, one or more locking means and a plurality of hydraulically activated clamping dies directed towards a centre axis of said power tong , said drive ring is located in said housing halves, said drive ring being supported and connected to a driving motor for the rotation of said drive ring about said centre axis, said drive ring and said locking means arranged to interconnect said first and second drive ring parts in a releasable manner.

11. The power tong in accordance with claim 10, said bayonet catch comprising a locking body hydraulically rotatable between an active and a non-active position.

12. The power tong in accordance with claim 11, said locking body comprising at least one locking dog, said locking body and said locking dog being located on one of said first and second drive ring parts and fitting complementarily into a recess in the opposite drive ring part, a rotation of said locking body about a centre axis moving said locking dog between the active and the non-active position.

13. The power tong in accordance with claim 12, further comprising said bayonet catch being rotatable by a movable index pin located in said drive ring, said index pin cooperating with an eccentrically mounted pivot on said locking body.

14. The power tong in accordance with claim 13, further comprising said index pin being movable by a corresponding hydraulic cylinder located in one of said housing halves.

15. The power tong in accordance with claim 13, further comprising said bayonet catch being in the inactive position and said index pin being moved into a piston recess in one of said first and second housing halves.

16. The power tong in accordance with claim 10, further comprising said first drive ring part and said second drive ring part each having a radial guide list and said drive ring parts bearing on each other along said radial guide lists, said first and second drive ring parts being arranged to be rotated about said guide lists in order to relieve said bayonet catch.

The present invention relates generally to power tongs and, more specifically, to power tongs that may be used for making and breaking connections in oil well tubular strings such as drill pipe and casing.

Power tongs have been used for many years for making and breaking tubular connections. However, as power tong systems have become larger and heavier so as to include back-up grips, spinners, and other valuable features that reduce time and improve reliability of the made up tubular connections, it has become necessary to build tracks and the like to control movement of the power tongs on the rig floor. The large size of and heavy weight of modern power tongs makes cable supports a less desirable means of supporting such systems. Movement of large heavy power tong systems either laterally or rotationally produces logistics problems on the rig floor and increases the likelihood of accidents.

U.S. Pat. No. 4,492,134, issued Jan. 8, 1985, to Reinholdt et al., discloses a power tongs for threadedly connecting together pipes which are to constitute casings for boreholes, which has a platform for a reciprocable slide which supports a power-driven threading clamp and a counter device. The clamp and the counter device are connected to each other by several level compensating hydraulic cylinders each of which is movable horizontally within limits relative to the slide against the opposition of resilient support elements. The upper end portions of the cylinders are connected to a holding plate for the clamp.

U.S. Pat. No. 4,082,017, issued Apr. 4, 1978, to Emery Eckel, discloses a hydraulically or pneumatically powered drill pipe tongs of the scissors-type used in making up or breaking apart joints of drill pipe, drill collars, and the like including an upper tong and a lower tong each including tong die heads for biting into or gripping the upper and lower joints of drill pipe, drill collars and the like with the upper and lower tongs being swivel connected and being swiveled by a hydraulically or pneumatically powered torqueing piston and cylinder assembly for rotating the upper and lower tongs in relation to each other when making up or breaking apart the drill pipe joints. Each of the upper and lower tongs includes a sliding door having one of the tong die heads thereon that can be moved a substantial distance toward and away from the tong body by the use of a pair of hydraulically or pneumatically powered piston and cylinder assemblies to enable tool joints, drill pipe protectors and the like to pass through the tongs while leaving the tongs on the pipe. Each of the tongs also includes a hinged mounting for one edge portion of the tong door and a latch for the other edge portion to enable the tong door to be latched or unlatched and swung outwardly in a manner to enable the tongs to be removed from the drill pipe when necessary.

U.S. Pat. No. 5,081,888, issued Jan. 21, 1992, to Joerg E. Schulze-Beckinghausen, discloses an apparatus for connecting and disconnecting threaded members including a power tong, a backup unit disposed below the power tong for tripping a second pipe, and apparatus for transmitting reaction forces generated by the power tong to the backup unit, the backup unit having devices for transmitting compressive or tensile forces between its members from the power tong which, in one embodiment, includes a hydraulic connection between a double acting hydraulic piston and cylinder assemblies incorporated in the members.

U.S. Pat. No. 6,138,776, issued Oct. 31, 2000, to Hart et al., discloses a pipe handling system comprising a rig floor supported frame adapted to be positioned above the rotary table and in alignment with the hole in the rotary table. It incorporates a centrally located bowl lined with the frame to enable a string of pipe to extend through the rotary table. Appropriate releasable slips are moved into and out engagement. The frame supports an overhead mounting plate, and one version thereof incorporates hydraulic jacks to raise and lower the mounting plate. The mounting plate supports a horizontally directed hydraulic ram which moves the two end lengths of a long multi length chain looped into a bight to go around a pipe passing near the end of the mounting plate. The bight in the chain grips the coupling of the pipe to hold it fast. This mechanism cooperated with an overhead power tong assembly to enable threading or unthreading of pipe casing and tubing.

U.S. Pat. No. 6,142,041, issued Nov. 7, 2000, to David A. Buck, discloses a power tong positioning apparatus, including a power tong support positionable on the surface of drilling rig deck and attachable to at least one power tong. The power tong support is adapted to position at least one power tong so that it may engage the tubular member. The power tong positioning apparatus a frame, a base moveably positioned on the frame, at least one arm pivotally attached to the base, a power tong support pivotally attached to the arm(s) and movably attachable to at least one power tong.

U.S. Pat. No. 6,142,040, issued Nov. 7, 2000, to Vernon J. Bouligny, discloses a spider, preferably a flush mounted spider, and powered lead tong which are coupled by a rotationally rigid structure so that torque reaction forces apply no side load to pipe. The tong preferably tilts upward to clear larger objects approaching the spider. An optional grabber is mounted, preferably atop the lead tong, and may tilt with the lead tong. Fluid powered motors, linear or rotary, provide the tilting energy and extend and retract the grabber. The tong and related structure has quick coupler provisions for removal from the spider.

The above power tong systems show tongs that either move laterally with respect to the pipe and/or have outer housings that rotate around the pipe and/or do not include a complete power tong assembly capable of spinning, backing up, applying torque, automatic slips, and the like. Consequently, it would be desirable to provide a system and method that is designed to avoid lateral and rotational movement of large power tong housings and provide virtually all functions required at the rig floor for making and breaking connections of either drill pipe or casing. Those skilled in the art will appreciate the present invention that addresses the above and other needs and problems. SUMMARY OF THE INVENTION

Therefore, in accordance with the present invention, an apparatus is disclosed for a power tong system for making and breaking connections in a tubular string. The power tong system may be used on a rig floor and comprises one or more elements such as a power tong housing, and at least one rotary drive tong mounted within the power tong housing for encircling and gripping a first portion of the tubular string. The rotary drive tong preferably has a rotatable gear therein for applying rotational force to the first portion of the tubular string. Other elements may include at least one backup tong having gripping elements therein for holding a second portion of the tubular string while the rotary drive tong applies the rotational force to the first portion of the tubular string. A plurality of lift assemblies may each include slidable shafts for moving the power tong housing upwardly and downwardly. The plurality of lift assemblies may be secured with respect to the rig floor such that the power tong housing is moveable upwardly and downwardly with respect to the rig floor and such that the power tong housing is prevented from rotating with respect to the rig floor.

Preferably the system includes powered slips operable for powered movement of slips into and out of gripping engagement with the tubular string. The powered slips are operable for supporting a weight of the tubular string.

In one embodiment, a collar locator produces a collar locator signal in response to at least one of the connections in the tubular string. A tong control is responsive to the collar locator signal for automatically controlling the upwardly or downwardly movement of the power tong housing for positioning the rotary drive tong and the backup tong with respect to one of the connections.

A drive gear may be provided within the at least one rotary drive tong which completely encircles the tubular string. A plurality of cams may be mounted to the drive gear for movement therewith. A removable section for the drive gear may be provided such that when removed the drive gear can be laterally moved away from the tubular string.

An expandable connection may be provided between the rotary drive tong and backup tong to permit relative up and down movement therebetween. Moreover, an extension member may be used for connecting between the at least one rotary drive tong and the at least one backup tong to permit the rotary drive tong and the backup tong to both grip either on a respective portion of the connection or simultaneously above and below the connection.

A plurality of piston driven gripping elements may be provided within the backup tong for selectively engaging and disengaging the second portion of the tubular string.

Thus, in one embodiment, the power tong system may comprise at least one rotary drive tong for gripping a first portion of the tubular string having a rotatable gear therein for applying rotational force to the first portion of the tubular string and at least one backup tong having gripping elements therein for holding a second portion of the tubular string while the rotary drive tong applies the rotational force to the first portion of the tubular string. A plurality of lift assemblies move the rotary drive tong upwardly and downwardly with respect to the rig floor. The plurality of lift members may be secured with respect to the rig floor. Powered slips are preferably provided that are operable for powered movement of slips into and out of gripping engagement with the tubular string for supporting a weight of the tubular string as desired. As well, a preferred embodiment includes a collar locator for producing a collar locator signal in response to at least one of the connections in the tubular string, and a control responsive to the collar locator signal for automatically controlling the upwardly or downwardly movement of the plurality of lift members.

A method for making or breaking connections in a tubular string as the tubular string is run into or out of a wellbore may comprise steps such as providing a power tong housing with a rotatable drive gear therein such that the power tong housing remains encircling the tubular string as the tubular string is run into or out of the wellbore. Other steps may include securing a back up power tong with respect to the power tong housing and/or moving the rotary drive tong and the back up power tong in a direction substantially parallel with respect to the tubular string. In a preferred embodiment, the method of the invention may comprise steps such as supporting the rotary drive tong to prevent rotation of the power tong housing during the making or breaking of the connections and/or producing an electronic signal in response to locating a connection. The method may further comprise positioning the rotary drive tong and the power tong backup in response with respect to the tubular string in response to the electronic signal. BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevational view, partially in section, of a power tong system in accord with the present invention with automatic slips in the open position as the elevators raise the pipe string;

FIG. 7A is an elevational view of a representative sliding connection for relative movement of a wrap around tong and back up clamp in an open position in accord with the present invention;

FIG. 7B is an elevational view of a representative sliding connection for relative movement of a wrap around tong and back up clamp in an open position in accord with the present invention;

FIG. 8 is an elevational view, partially in section, showing a power tong system in accord with the present invention having tong and backup above and below a joint of casing for gripping in accord with one embodiment of the invention;

FIG. 12 is a schematic view of one representative flush-mounted power slips assembly as part of a power tong system in accord with the present invention. BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings and, more particularly to FIG. 1, FIG. 2, and FIG. 3, there is shown a power tong system 10 in accord with the system of the present invention in different stages of operation. One problem the present invention is designed to eliminate is that of moving a large tong system laterally with respect to the pipe string for each joint to be connected or disconnected. Instead the present invention remains in the same lateral position and preferably does not rotate during operation. The present invention preferably remains wrapped around the drill string as the entire string is built into or removed from the wellbore. To further enhance operation, the present invention preferably incorporates powered slips therewith for improved operation as discussed hereinafter. The present invention preferably utilizes a collar locator for automatic height positioning, and also preferably utilizes an inspective device to locate or otherwise identify cracks, holes, leaks and other anomalies in the tubulars being made up or broken out of an oil well tubular string. Moreover, the tong system of the present invention incorporates a simplified arrangement as discussed hereinafter.

FIG. 1 discloses power tong system 10 in a retracted or lowered position with respect to rig floor 12. Power slips 14, shown schematically, are positioned upwardly in bowl 16 and therefore disengaged from tubular string 18 which is now supported by elevators 20. In FIG. 1, elevators 20 are used to lift tubular string 18 upwardly as indicated using rig blocks (not shown) for removing the pipe string from the wellbore. For installing tubular string 18, the process would be the reverse.

In FIG. 2, as the tubular string is removed the various joints for each stand pass through power tong system 10 until the desired joint to be broken, such as joint 22, is positioned within operating range of tong system 22. Joint 22 is the connection of an upper pipe 24 and a lower pipe 26 with respecting pin connection 28 and box connection 30. For operation of tong system 10 with drill pipe, it may be desirable or required that torque be applied only to the strengthened and enlarged or upset pin connection 28 and box connection 30. For operation of tong system 10 with casing, it may be more desirable or required that torque be applied to the pipe sections rather than the joint as suggested in FIG. 8, discussed hereinafter. Once connection 22 is positioned as desired, the operator engages power slips 14. Thus, an operator uses a control for tong system 10 to insert power slips 14 downwardly in bowl 16 to thereby support the weight of pipe string 18 so that connection 22 can be broken and pipe 24 or the stand to which pipe 24 connected can be removed such as for stacking.

FIG. 12 shows a schematic representation for power slips 34 flush-mounted with respect to rig floor 12 which may use power actuators such as actuators 32 for inserting or removing slips 14 with respect to bowl 16. FIG. 12 is only intended to be representative of power slips and other configurations can be used within tong system 10 of the present invention. One advantage of using power slips is improved safety in that personnel may then avoid having to work adjacent to moving equipment such as the power tongs. Since power tong system 10 does not move laterally from the pipe stand for each connection, automatic or powered slip operation increases safety of operation by reducing the need for personnel to work next to moving equipment.

Referring now to FIG. 3, once joint 22 is positioned and slips 14 are engaged, then power tong housing 36 must be posit