automated power tong american patent quotation

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.

BY W 51/15 105%! Ill March 17, 1970 J. H. WILSON AUTOMATED PIPE TONGS l9 Sheets-Sheet 5 Filed May 1, 1967 March 17, 1970 J. H. WILSON AUTOMATED PIPE TON-GS 19 Sheets-Sheet 6 Filed May 1, 1967 mww IN VENTOR.

AUTOMATED PIPE TONGS 19 Sheets-Sheet 10 Filed May 1, 1967 FIR JOHN HART WILSON INVENTOR ,L umv NOm Gm? QM Oh HIS AGENT March 17, 1970 J. H. WILSON AUTOMATED PIPE TONGS 19 Sheets-Sheet 11 Filed May 1, 1967 mN Wm (D Q JOHN HART WILSON INVENTOR.

AUTOMATED PIPE TONGS Filed May 1, 1967 19 Sheets-Sheet l5 mvsmom JOHN HART WILSON- March 17, 1970 J. H. WILSON AUTOMATED PIPE TONGS 19 Sheets-Sheet 16 Filed May 1, 1967 INVENTOR.

HIS AGENT March 17, 1970 J. H. WILSON AUTOMATED PIPE TONGS l9 Sheets-Sheet 18 Filed May 1, 1967 INVENTOR OHN HART W I LSQN HIS AGENT on mun u% 2m 3w! m9 n3 N3 w w mum mm 93 I r 0 r T an 03 com m on o ow wfi Q8. 02. N2. l gov wo dwown J r|..) 0%. 8 3 in. 2

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.

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.

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.

POWER TONGCRANE Filed Dec. 4.. 1957 3 Sheets-Sheet 2 INVENTORE. JOHN Z. D/C/L MA/V/V GAETH 1 N/LQLSOA/ ,4 7 7UE/VEV April 14,1970 J. L. DICKMANN ET AL v 3,505,913

POWER TONG CRANE Filed Dec. 4, 1967 3 Sheets- Sheet 3 INVENTORS. JOHA/ D/CKMA/V/V I /jwmwa/v /7 I g m I i 1 V l A7, I 4 1 A TTOEA/(EV United States Patent 3,505,913 POWER TONG CRANE John L. Dickmann, Whittier, and Garth F. Nicolson, Huntington Beach, Calif., assignors to Byron Jackson Inc., Long Beach, Calif., a corporation of Delaware Filed Dec. 4, 1967, Ser. No. 687,812 Int. Cl. B25b 1 3/ 50, 29/00 US. Cl. 81-5735 17 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION The present invention relates to power pipe tongs, and more particularly to power pipe tongs useful in the making up and breaking out of joints of well pipe, such as drill pipe or casing, as the same is being run into or pulled from a well bore.

In the use of power pipe tongs in the running and pulling of well pipe such as drill pipe or casing, particularly in the event that the pipe-handling derrick equipment may be operated automatically or remotely, it is often desirable that the power tong mechanism used to make up and break out pipe joints be supported so as to be readily movable horizontally as well as vertically between working and non-working positions. Therefore, various support structures have heretofore been employed; including cables and hoists, as well as fluid-pressure operated cylinders which are adapted to elevate and lower the tong assembly, as may be necessary to allow pipe to be speared into the pipe already in the well bore, or to allow pipe already in the well bore to be engaged by an elevator so as to be pulled therefrom. Periodically, moreover, it is necessary that the tong be shifted horizontally between a working position at which the tong head overlies the well bore, and a non-working position at which the tong assembly is off to one side of the well bore enabling the performance of other operations without interference from the tong assembly.

Generally the power tong assemblies are quite massive and it is therefore desirable that they be supported so as to not only facilitate manipulation of the tong assembly, but also to reduce strain on the supporting structures for the tong assembly.

SUMMARY Accordingly, an object of the invention is to provide a tong-supporting crane structure which is of rigid construction, capable of supporting a tong assembly in a suitable manner.

Another object of the invention is to provide a tongsupporting crane structure operable to suspend the tong assembly in a working position with the tong head overlying the well bore and at different elevations, namely, a first elevation at which an elevator may engage a length of pipe disposed in the well bore so as to remove the same from the well bore, and a second elevation at which the tong head may be operated to grip and rotate a length of pipe suspended in the derrick so as to either make up or break out the joint between such stand of pipe and a length of pipe disposed in the well bore.

3,505,913 Patented Apr. 14, 1970 Still another object is to provide a tong-supporting crane structure which may be readily operated to move the tong assembly vertically or horizontally between working and non-working positions, and wherein the tong assembly is at all times supported substantially at its center of balance. In accomplishing this objective a tong-supporting structure is provided wherein the tong is pivotally supported upon a slide movable vertically on a post, and adjustable cables are connected to the slide and to an outwardy extended portion of the tong assembly, and both of said cables may be simultaneously operated to raise and lower the tong assembly. Moreover, the tong assembly may be swung horizontally to a position remote from the well bore to allow the conduct of other operations at the well bore.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top plan view illustrating a power tong assembly supported above a drilling rig floor by a crane assembly made in accordance with the invention;

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to FIGSS. 1 and 2, there is generally illustrated a tong assembly T adapted to be supported above the floor F of a drilling platform which may be part of the usual drilling rig mounted above a well bore and into which pipe, such as drill pipe or casing, is adapted to be run and from which such pipe will be some times pulled, as in the case of drill pipe. Such a pipe is illustrated in FIGS. 1 and 2 as including an upper stand of pipe P1 in the illustrative form of a stand of drill pipe having a tool joint pin end 1 thereon adapted to be threadedly connected by the tong T to the box end 2 of a length or stand of the pipe P2 disposed in the well bore. In order to support the tong assembly T in an operative position above the well bore so that the stand of pipe P1 may be lowered therethrough for engagement with the pipe P2, a crane C made in accordance with the present invention is provided, including a boom 3 projecting from a vertically disposed post 4. A cable 5 connected to a support framework 5a which is in turn connected to the tong T, extends over sheaves 6, 6 and is connected to a pressure operated cylinder mechanism 7 disposed within the post 4, whereby the tong assembly T may be raised and lowered relatively to the post 4 and thereby relative to the well bore into which or from which pipe is being removed. Also forming a part of the crane C is a slide support 8 shiftable vertically along the post 4, there being a second cable 9 also connected to the upper end of cylinder 7, extending over sheaves 10, and connected also to the slide support 8 so that the mass of the tong assembly may be properly supported.

The tong assembly, as is typical of tongs of the type here involved, includes a head section generally denoted at 11 and a supporting and power transmission section generally denoted at 12. The latter section in the illustrative embodiment has a hydraulic motor 13 adapted to be connected to a suitable source of motive fluid under pressure so as to drive the transmission mechanism of the tong assembly, which may be of any desired type, but which may preferably be constructed in accordance with the disclosure in the application for United States Letters Patent filed concurrently herewith and entitled Power Pipe Tong Transmission Assembly, Ser. No. 687,815 filed Dec. 4, 1967.

The tong head section 11 may be of any desired construction adapted to grip and rotate the tool joint 1 of the pine P1. Illustratively, the tong head may be constructed in accordance with the disclosure in the application for United States Letters Patent filed concurrently herewith and entitled Pipe Tong Head, Ser. No. 687,830 filed Dec. 4, 1967.

In order to make or break the joint, the tong head is operated at least to initially break out or finally make up the joint while the box end 2 of the pipe P2 is held nonrotatively in a back-up tong generally denoted at B. This. back-up tong may be of any desired construction, but is preferably made in accordance with the disclosure in the application for United States Letters Patent filed concurrently herewith and entitled Back-Up Tong for Power Pipe Tongs, Ser. No. 687,810 filed Dec.4, 1967.

As previously indicated, the post 4 and the boom 3 projecting therefrom are adapted to suspend the tong assembly T in different horizontally spaced positions. Therefore, the flange 20 is provided with a plurality of angularly spaced notches 21 adapted to receive a spring loaded detent 22, this detent 22 being slidably supported in an opening 23 provided in a detent support 24, this support 24 being fastened to the flange 18 forming a part of the socket 14 as previously described. The two locations of angular adjustment of the post 4 represented by the notches 21 are: first, the location shown in FIGS. 1 and 2 at which the tong head 11 would be supported above a well bore for making up and breaking out pipe joints and second, a position at which the tong assembly has been swung off to an out of the way position, allowing other operations at the well bore. From time to time it may be necessary or desirable to secure the post 4 and boom 3, and therefore the tong, in some other angular position than the fixed positions provided for by the notches 21. Therefore, as best seen in FIG. 6, a brake is provided in the form of a clamping foot 25 having a toe 26 engaged beneath a flange 27 on the bushing 19, the foot having a stem 28 extending through the flange 20 and engaged by a nut 29, whereby a clamping force may be developed to grip the flange 27 between the toe 26 and the flange 20 at various other angular positions of the boom and tong relative to the well bore.

The cable 9 which, as previously described, is connected to the slide 8 may be connected thereto as by shackle means 42. Referring to FIGS. 7 and 9, a pair of brackets 43 is disposed between the opposing walls 35 adjacent the tong assembly T, and these brackets 43 support a pivot pin 44 on which is loosely disposed one end of a link 45, the other end of which is loosely disposed upon a pivot pin 46. This pin 46 extends through a pair of brackets 47 projecting from the side of the case of the power tong assembly and, more particularly, from the case of the transmission section 12 of the assembly. Thus, the tong assembly T is supported for slight universal movement as may be required from time to time to adjust the position of the tong assembly relative to a pipe joint 1, or so as to allow slight tilting of the tong assembly when the threaded joint parts 1 and 2 are being spun, an operation which causes movement of the tong assembly T toward or away from the back-up tong B.

In order that the slide 8 and the tong assembly T will move vertically without substantial tilting, the cables 5 and 9 extend downwardly into post 4 and are connected to an eye 48 provided at the upper end of the rod 49 forming part of a fluid pressure operated cylinder assembly generally denoted at 7 which provides means for pulling downwardly upon the ends of the cables 5 and 9, whereby to simultaneously lift the slide 8 and the body of the tong assembly T. As best seen in FIGS. 7 and 10, the fluid pressure operated cylinder assembly includes an elongated tubular body 51 in which is reciprocably disposed a piston 52, the inner end of the rod 49 being connected to the piston 52. A fluid inlet fitting 53 is provided for admitting pressure fluid into the body 51 above the piston 52, the fitting 53 being connected by conduit 54 which is, in turn, connected to an inlet fitting 55 adjacent the lower end of the post 4, the conduit 54 extending upwardly through the annular clearance defined between the post 4 and the body 51 of actuator cylinder 7. Operating fluid from a suitable source (not shown) may be provided from a remote location, so that fluid pressure forcing the piston 52 downwardly will move the rod 49 downwardly in the relatively stationary body 51, thereby pulling the cables 5 and 9 downwardly in the post 4, elevating the tong assembly T and the slide 8.

At its lower end, the body 51 is provided with an end section 56 which is connected within the base 16 of the substructure previously described, as best illustrated in FIG. 10. The lower end section 56 of the actuator body 51 is provided with a knob-like portion 57 adapted to be engaged by a pair of retainers 58 to prevent upward movement of the actuator body 51, while allowing slight angular cocking of the body 51 relative to a vertical position. The retainers 58 are substantially semi-circular parts each having an upper flange 59 extended inwardly in opposing relation within a channel 60 formed in the end section 56 of the actuator body 51 and defining a reduced stem 61. For purposes of assembly, a resilient band 62 is provided for initially holding the retainers 58 in assembly with the knob-like end 57 when the actuator body is downwardly displaced from the base 16. Thereafter, the body 51 may be moved upwardly so that the retainers 58 are disposed in a bore 63 provided ina base support 64 which is welded or otherwise connected to the lower end of the post 4, this base support 64 having a cylindrical section 65 seating within the substructure base support 16. Suitable fasteners 66 may be provided for securing the retainers 58 in the bore 63, so as to support the actuator assembly 7 against downward movement in the post 4 until the tong assembly T and the slide 8 are connected to the cables 5 and 9, respectively, whereupon the entire weight of the assembly will act to pull upwardly upon the actuator cylinder 7 and the latter will be held against upward movement by engagement of the knob-like section 57 with the retainer flange 59. From the foregoing it will be appreciated that the retainers 58 and the knob-like section 57 essentially constitute a swivel or ball-and-socket connection, whereby the actuator cylinder 7 may cock angularly within the post 4 into alignment with the line of force imposed thereon by the connected ends of the cables 5 and 9.

-In the operation of the crane structure, and in the use of the tong assembly, it will be now understood that the elevation of the tong assembly may be adjusted simply by supplying or exhausting pressure fluid, preferably hydraulic fluid, to or from the actuator cylinder above piston 52. When pipe, such as drill pipe, is being run into or pulled from a well bore, the elevation of the tong assembly will be adjusted each time a joint, composed of the tool joints 1 and 2, is made up or broken out. For example, when the joint is to be made up, a tool joint 1 of the pipe P1 will be stabbed into the tool joint 2 of the pipe P2, whereupon the tong assembly T will be operated to rotate the pipe P1 to establish the threaded joint, the back-up tong B being operated to hold the pipe P2 at least during the final stages of make up of the joint. Thereupon, both the back-up tong B and the power tong assembly T will be disengaged from the pipe and the entire assembly must be lowered to allow the hoist equipment in the derrick, by which the pipe P1 is suspended, to be lowered so as to lower the string of pipe into the well bore, the hoist equipment lowering the pipe string until the upper joint part of the pipe P1 is in the same relative position as the pipe P2 shown in FIG. 2. Thereafter, the pipe in the well here would be supported in the usual slips (not shown) and the hoist equipment would then be removed from the pipe and re-elevated. It is then necessary to raise the tong assembly to the same relative position as shown in FIG. 2, so that a new joint may be made up. It is also necessary that the tong assembly, including the back-up tong B, be shifted between a working position and a lower position when joints of pipe are being broken out.

In addition to the foregoing, when it is desired to perform other operations over the well bore, it is necessary that the tong assembly be swung off. Under these circumstances, it is necessary that the tong assembly be elevated so that the back-up tong B will clear the upper end of the pipe P2. Thereupon, the tong assembly may be swung in a horizontal plane about a vertical axis, the post 4 under such circumstances turning within the socket 14. The latch member 22, accordingly, should be released from the notch 21 in flange 20 in which it is engaged during the normal working position of the tong assembly and, when the tong assembly is in the swung off position, the latch member 22 may re-engage in the other notch 21, or, alternatively, the clamp 25 may be operated as previously described to clamp the flange 20 in any desired angular disposition relative to the bushing 19.

1. In tong apparatus for making up and breaking out joints of well pipe during running of said pipe into and pulling of said pipe from a well bore, including power tong means for rotating a pipe joint part relative to another joint part, and means for positioning said tong means in operative posit