dc power tong llc in stock
DC Power Tong continues to set the standard in the casing and tubing service industry by offering superior service & innovative casing technology. To exceed our customersʼ expectations, DC Power Tong also provides hydro test trucks, pressure test units, and equipment and pipe wrangler rentals to ensure your project is completed safely and efficiently. At DC Power Tong, we treat your project as if it is our very own, and thatʼs what weʼre all about.
DC POWER TONG LLC is a motor carrier operating under USDOT Number 3303149 in North-dakota. It has a total of 2 trucks and 2 drivers. The company received its MCS number on 08-DEC-19.
According to our records, in 2018 DC POWER TONG LLC company drivers travelled 1 miles and had a total of 1 inspections and 1 out of which were with violations. This transportation company drivers had 0 crashes with 0 crashes involving a fatality.
FIRE TONGS AND FIRE POKER SET OUTDOOR GARDEN LAMP PATIO COVER COMPUTER DESK&GAMING DESK S TORAGE BOX WHEEL HUB BEARING CONTROL ARM STEERING SHAFT WATER PUMP TENSIONER POWER STEERING PUMP EGR VALVE MUD FLAPS FULL CAR COVERS TRUNK ORGANIZERS WOOD ORGANIZER
IB: POWER MOP SET 2023 HS:960 3.90 ADD NOTIFY 3 ALDI SOURC ING ASIA LIMITED 18/F, MILLEN NIUM CITY 6, 392 KWUN TONG R OAD, KWUN TONG, KOWLOON, HONG KONG -PHONE 718-425-1022 FAX 973-686-4192 IB: POWER MOP SET 2023 HS:960 3.90 ADD NOTIFY 3 ALDI SOURC ING
GREETING CARD VELVET BAG THREAD PROT ECTOR TILE LEVELER PRINTER DE HYDRATION EQUIPMENT BLANKET GLASS BOTTLES METAL PARTS PHOTO BOOTH WORKOVER POWER TONG LED PANEL LIGHT PLASTIC BAG
ICE MAKER WORKOVER POWER TONG BARBER CHAI R MEN S SHIRTS CARBON FISHING ROD WOR KOVER POWER TONG CONGAS SWEATER PHOTO BOOTH INFLATABLE BOUNCER COMPUTERIZED E MBROIDERY MACHINE PLASTIC BAG
CAR CUP HOLDER CARBON TUBE TAPE MEASURE INFLATABLE JUMP BED PLASTIC COMB COMPU TERIZED EMBROIDERY MACHINE COMPUTERIZED EM BROIDERY MACHINE WORKOVER POWER TONG SE AT COVER MEN S SHIRTS COMPUTERIZED EMBR OIDERY MACHINE CLEANING MACHINE RAKE HEAD HEAT PRESS
CUTTING BOARD 8.5X11 W GRIP MCCORMICK SALAD TONGS POWER CLPS NVLTY 3PK 2 ASTD CS SINK SPONGE HOLDER ASTD MCCORMICK KITCHN BRUSH SILICON MEASURING CUP&SPOON 8PC MCCORMICK SLOT SPOON NYLOON MCCORMICK MELAMINE TOOL ASTD MCCORMICK SLOTTED TURNER NYLON MCCORMI
INFLATABLE JUMP BED BALL VALVE INFLATABLE JUMP BED WORKOVER POWER TONG INFLATABLE JU MP BED PLASTIC BOTTLE SCARF COMPUTERIZE D EMBROIDERY MACHINE MEN S SHIRTS INFLATA BLE JUMP BED PILLOW INFLATABLE JUMP BED I NFLATABLE JUMP BED YOGA CLOTHES INFLATABLE JUM
FOOTBALL GATE WORKOVER POWER TONG WORKOV ER POWER TONG BELT MEN S SWEATER CANVA S BAG TROUSERS SEWING MACHINE TABLE EYE MODEL STAGE CABINET CARAVAN LOCK BLANK ET PLASTIC HOOK
LINEN INFLATABLE JUMP BED SUCKER ROD CENT RALIZER PLASTIC BOX WORKOVER POWER TONG OXFORD FABRIC INFLATABLE JUMP BED KNITTED WOMEN S OPEN CHEST SHIRT INFLATABLE JUMP B ED GLASS MOSAIC INFLATABLE JUMP BED DOO RMAT
LINEN INFLATABLE JUMP BED SUCKER ROD CENT RALIZER PLASTIC BOX WORKOVER POWER TONG OXFORD FABRIC INFLATABLE JUMP BED KNITTED WOMEN S OPEN CHEST SHIRT INFLATABLE JUMP B ED GLASS MOSAIC INFLATABLE JUMP BED DOO RMAT
ENVELOPE HTS: FIRE-TONGS HTS: FIREPLACE TOOLS SET HTS: FOLDABLE STEPLADDERS OF STEEL HTS: KRAFT BUBBLE MAILER HTS: LOG STORAGE RACK SET HTS: PE COURIER BAG HTS: PLASTIC STOOL HTS: POWER INVENTER HTS: TABLE MAT WOODEN HANGER KITCHEN UTENSILS HTS: CERAMIC T
Convenient to use and exceptionally durable, these tongs are designed with a spring-action mechanism for effortless handling and are crafted from heavy duty stainless steel.
This application claims priority from U.S. Provisional Patent Application No. 61/064,032 filed Feb. 12, 2008 entitled Power Tong, and U.S. Provisional Patent Application No. 61/071,170 filed Apr. 16, 2008 entitled Power Tong.
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. They 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. 1 a. 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 an 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 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 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 that has grippers that grip the tubular. Hydraulic and electrical power necessary for actuating the grippers is generated on board the rotating jaw since the continuous rotation does not allow for either hydraulic or electrical external connections. A serpentine drive belt system turns the motors of an on-board hydraulic power unit and electric generators to supply the grippers with the necessary hydraulic and electrical power.
The present invention includes a main drive, rotary jaw and back-up jaw. The rotary jaw is supported and held in position by the use of opposed helical pinions/gears which support the rotary jaw vertically and guide bushings which locate it laterally. The rotary jaw hydraulic gripper cylinders are held in position by links and guide bushings that can withstand the torque parameters of the tong. Gripper cylinders can 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 9⅝ inch casing or larger). This large range can be accomplished without changing gripping jaws or jaw holders. A centralizing linkage ensures that the pipe is gripped concentrically 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 hydraulic gripping of the tubular. It is capable of high torque for making and breaking and high speed for spinning, all within one mechanism. 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 open throat of the jaws according to the present invention allows the power tong to be selectively positioned around the pipe at the operators" discretion.
As seen in FIGS. 1 and 2, the power tong 6 according to the present invention may be characterized in one aspect as including three main sections mounted on a common axis A; namely a main drive section, a rotary jaw, and back-up jaw. Each of the sections contains actuators, as better described below. The main drive section 10 is located about the rotary jaw 22 and the backup jaw 48. The rotary jaw rotates relative to the main drive and back-up jaw. Both the rotary jaw and backup jaw clamp their respective sections of pipe. The rotary jaw is rotated by the main drive section independently of the other two sections in the sense that the rotary jaw 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 rotary jaw while the other, oppositely disposed section of pipe is held clamped in the center of the back-up jaw.
As shown in FIGS. 1, 2 and 3 rotary jaw section 22 is housed within drive section 10. The rotary jaw 22 is cylindrical in shape and has an opening slot having a throat 38 allowing the tong axis of rotation A to be selectively positioned concentric with pipe 8, provided the rotary jaw 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 section 22 has three gripper actuators 44 a, 44 b, and 44 carranged radially, with approximately equal angular spacing around axis A, mounted between the two parallel horizontal planes containing rotary jaw gears 30 aand 30 b.
Serpentine belt 20 is driven by two serpentine drive hydraulic motors 18 driving drive sprockets 26 awhich collectively provide a secondary drive powering the grippers on the rotary jaw. Drive sprockets 26 arotate serpentine belt 20 about idler sprockets 26 mounted to drive section 10 and six serpentine drive node sprockets 32 a-32 fmounted on the rotary jaw section 22. The serpentine drive node sprockets include in particular two generator drive sprockets 32 aand 32 b, two pump drive sprockets 32 cand 32 dand two rotary jaw idler sprockets 32 eand 32 f. In the illustrated embodiment, the generator drive sprockets, 32 aand 32 b, transmit rotary power to generators 34, and the pump drive sprockets 32 cand 32 dtransmit rotary power to hydraulic pumps 36 by the action of serpentine belt 20 engaging the upper groove of sprockets 32 a, 32 b, 32 cand 32 d. A synchronization belt, 28 a, connects the lower portions of the rotary-jaw sprockets 32 a-32 f. Thus as the rotary jaw section 22 rotates on axis of rotation A about its full three hundred sixty degree rotational range of motion, even though serpentine belt 20 cannot extend across the opening throat 38 because such a blockage would restrict selective positioning of the pipe along the slot into the tong, serpentine belt 20 wraps in a C-shape around the serpentine drive node sprockets 32. Serpentine belt 20, driven by drive sprockets 26 a, runs on pulleys 26, 26 b-26 cmounted to, so as depend downwardly from, main drive section 10. The extent of the C-shape of serpentine belt 20 provides for continual contact between serpentine belt 20 and a minimum of three of the rotary jaw sprockets 32 a-32 fas the rotary jaw rotates relative to the main drive. The synchronization belt 28 mounted on the rotary jaw maintains rotation of the individual rotary-jaw sprockets as they pass through the serpentine gap 29 seen in FIG. 4, that is, the opening between idler pulleys 26 band 26 c. Synchronization belt 28 synchronizes the speed and phase of the rotation of each of the rotary jaw drive sprockets 32 a-32 fto allow each of them in turn to re-engage the serpentine belt 20 after they are rotated across the serpentine gap 29 by the action of the rotary jaw rotating relative to the main drive.
During operation of the tong the secondary drive (drive motors 18) and belt 20 run continuously to deliver power to the on-board pumps and generators by means of the drive node sprockets 32 a-32 d. Rotation of the rotary jaw by the operation of the primary drive acting on the pinions 56 and ring gears 30 aand 30 bdoes not substantially affect the powering of the on-board accessories (pumps and generators) because the belt 20 is run at substantially an order of magnitude greater speed than the speed of rotation of the rotating jaw. The rotation of the rotary jaw only adds or subtracts a small amount of speed to the rotation of the drive node sprockets.
Upper rotary jaw gear 30 aand lower rotary jaw gear 30 bare parallel and vertically spaced apart so as to carry therebetween hydraulic pumps 36, generators 34, the rotary jaw hydraulic system, rotary jaw electrical controls and the array of three radially disposed hydraulic gripper actuators 44 a, 44 b, and 44 c, all of which are mounted between the upper and lower rotary jaw ring gears 30 aand 30 bfor rotation as part of rotary jaw section 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 rotary jaw section 22 and powered via a nested transmission, nested in the sense that the C-shaped synchronization drive loop mounted on the rotary jaw, exemplified by belt 28 a, is nested within so as to cooperate with the C-shaped serpentine drive loop mounted to the main drive, exemplified by belt 20.
Thus as used herein, the serpentine belt 20 and paired drive pulley transmission is 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 of the stage.
For proper operation of the tong, it is desirable that the gripper cylinders 44 clamp the tubular 8 at or very 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 1 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 opening 38. It is an advantage of the link design that it requires less stroke to clear the throat opening 38 due to the swing associated with the arc of reaction links 44 e, which ultimately allows a more compact rotary jaw 30 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, the rotary jaw 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 the rotary jaw section 22 to store energy to enable rapid extension of the gripper actuators 44 a-44 c. In this way, very fast gripping speeds may be achieved while keeping the power transmitted by the serpentine belt 20 drive low. That is, although the power supplied via the serpentine drive is small, the rotary jaw 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.
A schematic of the preferred rotary jaw hydraulic system is shown in FIG. 10. The system has one or two gear or piston pumps 36 of relatively small capacity, within the power limitations of the serpentine drive. When there is no gripping demand, the pumps charge one or more gas-filled accumulators 55 to store energy for intermittent peak demands. 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 rotary jaw 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 rotary jaw 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 rotary jaw 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.
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 device 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 rotary jaw PLC 70.
The rotary jaw 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 64 to control the grip pressure. It also receives feedback from sensors 73 on the rotary jaw 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 rotary jaw grippers and the back-up jaw grippers. If either jaw grips across the split, the tool joint and the tong may be damaged and time will be wasted because the connective 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.
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.
The system is installed within, above or below the tong, oriented such that the light band 205 is in a plane perpendicular to the axis of the pipe and with the light band 205 passing across the center axis of the tong so that the pipe will interrupt the light band 205. If the width of the light band 205 is less than the outside diameter of the drill pipe tool joints than a tandem configuration can be employed as shown in FIG. 18.
The system can quickly and accurately measure the diameter of any tubular passing through the plane of the light band(s) 205 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, tong is preferably mounted on a manipulator 99 as shown in FIGS. 12 aand 12 b. 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. 12 aand the parked position of FIG. 12 b. 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 toque 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 (stewing motor 101 and linear actuators 104, 105 and 106). However, if 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 stewing 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 stewing orientation is measured preferably by an encoder 110 on the stewing 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 stewing 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.
This is a Continuation-in-Part of U.S. patent application Ser. No. 12/379,090 filed Feb. 12, 2009 entitled Power Tong, now U.S. Pat. No. 8,109,179, which claims the benefit of U.S. Provisional Application No. 61/071,170 filed Apr. 16, 2008 entitled Power Tong and of U.S. Provisional Application No. 61/064,032 filed Feb. 12, 2008 entitled Power Tong.
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. 1 a. 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 9⅝ 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. 19 ais 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 e, 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.
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 pumps) 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.
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. 12 aand 12 b. 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. 12 aand the parked position of FIG. 12 b. 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.
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 sid