Axial linkage with fluid-powered latching mechanism

Abstract

A latching axial linkage comprises a drive cam body coaxially and threadingly engaging an intermediate cam body that coaxially and threadingly engages a driven cam body, with the drive cam body thread direction being opposite to the driven cam body thread direction, plus fluid actuation means for transmitting axial load between the drive cam body and the driven cam body. The fluid actuation means may be a linear fluid actuator comprising a piston having an axial bore and being axially movable within an annular piston chamber defining a retraction fluid chamber on one side of the piston and an extension fluid chamber on the other side of the piston, such that the fluid actuator will urge either shortening or lengthening of the axial linkage according to the fluid pressure differential across the piston. An optional fluid signalling system may be used to indicate an operational state of the axial linkage.

Description

[0001] AXIAL LINKAGE WITH FLUID-POWERED LATCHING MECHANISM

[0002] FIELD

[0003] The present disclosure relates in general to means for controlling the latching function of axially-acting mechanisms, and relates in particular to mechanisms for controlling the “retract” and “engage” functions of casing running tools (CRTs) deployed on top-drive-equipped drilling rigs.

[0004] BACKGROUND

[0005] The traditional method for running casing or other tubing strings into or out of petroleum wells has been to use power tongs in coordination with the drilling rig’s hoisting system. This power tong method allows tubular strings, made up of multiple segments (or “joints”) of pipe with mating threaded ends, to be assembled by screwing together the threaded ends to form threaded connections between sequential joints as they are added to the string being installed in the wellbore (i.e., connection “make-up”); or, conversely, removed and disassembled (i.e., connection “break-out”).

[0006] However, the power tong method does not simultaneously enable other beneficial functions such as rotating, pushing, or fluid filling after a joint has been added to or removed from the string, and while the string is being lowered or raised in the wellbore. Running tubulars with power tongs also typically requires the presence of personnel in hazardous locations such as on the rig floor or, more significantly, above the rig floor, on what is commonly called the “stabbing board”.

[0007] The advent of drilling rigs equipped with top drives has enabled a new method of running tubulars, and casing in particular, where the top drive is equipped with a casing running tool (CRT) to grip the upper joint of the casing string and, in some cases, to seal between the casing and the top drive quill. (It should be understood here that the term “top drive quill” is generally considered to mean combination of the top drive quill and such tubular string components as may be attached thereto, with the lower end of this combination effectively acting as an extension of the quill.) Various CRT devices have been developed which, when used with a top drive, enable hoisting, rotating, pushing, and filling of the casing string with drilling fluid while running, thus removing the limitations associated with power tongs. Simultaneously, automation of the CRT’s gripping function, combined with the inherent advantages of the top drive, reduces the required level of human involvement compared with conventional power tong running processes, and thus improves safety.

[0008] When running casing with either power tongs or CRTs, the full weight of the casing string extending below the drill floor of the drilling rig is typically supported, and rotation of the casing string is prevented, by slips provided in the drill floor while a casing joint (the “active joint”) is being added to or removed from the string. As well, make-up torque and break-out torque applied to the active joint must also be reacted out of the assembled string; this function is typically provided either by the slips or by backup tongs, as the case may be.

[0009] U.S. Patent No. 7,909,120 (Slack) discloses a gripping tool that has been used as a CRT, and which may be summarized in general terms as a gripping tool comprising:

[0010] • a main body assembly (or, more briefly, the main body) having a load adaptor adapted for connection to a drive head such as a top drive quill;

[0011] • a gripping assembly carried by the main body, having at least one grip surface adapted to move from a radially -retracted position to a radially-extended position in which the grip surface engages either an interior surface or an exterior surface of a tubular workpiece upon axial displacement of the main body relative to the grip surface in at least one axial direction; and

[0012] • a linkage (i.e., a type of mechanism) acting between the main body and the gripping assembly which translates at least one range of rotational movement in at least one rotational direction into axial movement that tends to urge the grip surface into the engaged position (i.e., gripping a tubular workpiece), and which upon activation exerts an axial force that increases with increased torque, and correspondingly activates radially-compressive tractional engagement of the grip surface with the workpiece, with the rotational movement to activate the linkage being bi-directional - i.e., either clockwise or counter-clockwise rotation of the load adaptor relative to the grip surface. This prior art gripping tool thus utilizes a mechanically-activated mechanism that generates its gripping force in response to axial-stroke activation of the gripping assembly. Axial-stroke activation results from one or more of:

[0013] • the action of an internal spring, which may be an air spring;

[0014] • gravity;

[0015] • externally-applied axial load; and

[0016] • externally- applied torsional load, in the form of either right-hand or left-hand torque.

[0017] The externally- applied axial or torsional loads are carried through the gripping tool from the load adaptor of the main body to the grip surface of the gripping assembly, in tractional engagement with the workpiece. As will be apparent to persons of ordinary skill in the art, the utility of this or other similar gripping tools is a function of the range of workpiece sizes (typically expressed in terms of minimum and maximum diameters for tubular workpieces) that can be accommodated between the fully-retracted and fully-extended grip surface positions of a given gripping tool (i.e., the radial size and radial stroke of the grip surface). The utility of a given gripping tool can be improved if it can accommodate a greater range of workpiece sizes.

[0018] U.S. Patent No. 8,424,939 (Slack) discloses a gripping tool incorporating an axial extension linkage (comprising a drive cam body, an intermediate cam body, and a driven cam body) to translate bi-directional rotation into axial movement that has the effect of extending the axial length of the axial extension linkage and thus drives axial-stroke activation of the tool’s gripping assembly. The axial operating range of this prior art axial extension linkage is limited by the helical ramp surfaces acting between the intermediate cam body and the driven cam body. This prior art linkage also comprises mating latch hooks (or a “J-latch” mechanism) that, when engaged, prevent relative axial separation of the drive cam body and the driven cam body, thus preventing extension of the linkage. (For purposes of the present disclosure, such axial extension linkages comprising a drive cam body, an intermediate cam body, and a driven cam body may be alternatively referred to as “tri-cam linkages”.)

[0019] U.S. Patent No. 11,560,761 (Slack) discloses a gripping tool incorporating a variablelength axial extension linkage that can provide operational advantages over prior art linkages such as those disclosed n US 7,909,120 and US 8,424,939, including one or more of the following:

[0020] • greater axial operating range for a given diameter of tubular;

[0021] • the ability to transfer both compressive and tensile axial loads when unlatched (instead of transferring only compressive axial load when unlatched); and

[0022] • the ability to re-latch using any of several alternative operational sequences (instead of being re-latchable only by following one specific operational sequence).

[0023] This prior art linkage also comprises a drive cam body, an intermediate cam body and a driven cam body. The drive cam body and the intermediate cam body are threadingly engaged via a drive thread. The intermediate cam body and the driven cam body are threadingly engaged via a driven thread. Additionally, this prior art linkage comprises mating latch and striker bodies that, when engaged, will constrain relative rotation between the intermediate cam body and the driven cam body. Furthermore, the drive thread of this prior art linkage must be configured to be self-locking to prevent unintentional unlatching and extension of the linkage when the drive cam body is in its latching position. A self-locking thread has sufficient friction to prevent rotation when axial load is transferred between threadingly engaged components.

[0024] The use of hydraulic pressure to engage and retract CRT grip surfaces is well known in the art for CRTs that do not feature torque activation. Such prior art hydraulically-activated tools must provide sufficient radial “set force” to enable torque transfer through the gripping surface to a tubular workpiece to prevent slippage. Applying too much or too little hydraulic force can cause excessive damage to the surface of the tubular workpiece.

[0025] In contrast, CRTs featuring torque activation such as those taught in US 7,909,120, US 8,424,939, and US 11,560,761 require only a relatively small initial radial set force to initiate the grip. Subsequent bi-rotational motion of the load adapter relative to the gripped tubular workpiece increases the radial set force proportionally with the applied torque transferred through the gripping surface to the tubular workpiece. BRIEF SUMMARY OF THE DISCLOSURE

[0026] The present disclosure teaches non-limiting embodiments of a variable-length axial extension linkage (alternatively referred to herein as simply an “axial linkage”) incorporating a fluid- actuated (alternatively, “fluid-powered”) latching mechanism, for use with tubular running tools (CRTs) and retaining advantages provided by prior art linkages, such as those disclosed in US 7,909,120, US 8,424,939, and US 11,560,761, including but not limited to:

[0027] • bi-directional rotational activation of the CRT gripping assembly; and

[0028] • capability for a large axial operating range for a given diameter of tubular.

[0029] Such axial linkages with fluid-powered latching mechanisms (alternatively referred to herein as “fluid-powered latching axial linkages”, “fluid-powered latching linkages”, or simply “fluid-powered linkages”) in accordance with the present disclosure can also provide operational advantages over prior art linkages, such as (by way of non-limiting example):

[0030] • the ability to re-latch (i.e., retract) the linkage, independent of the relative rotational position between the drive cam body and the driven cam body, by means of externally- applied fluid pressure (such as by one or more hoses connected to the CRT and / or by externally- applied axial load) - meaning that the linkage does not require left-hand torque (the conventional direction of tubular breakout) to re-latch the CRT after a connection makeup in prior art;

[0031] • the re-latch sequence of the fluid-powered linkage may be initiated regardless of the instantaneous angular position and axial extension, as opposed to following a specific operational sequence; and

[0032] • the ability to react both tensile and compressive loads through the fluid-powered linkage when unlatched.

[0033] Embodiments of fluid-powered latching axial linkages in accordance with the present disclosure may be configured for use in prior art gripping tools such as those disclosed in US 7,909,120, replacing the prior art latching linkages therein.

[0034] As used in the present disclosure, the terms “drive cam body” and “driven cam body” and, similarly, “drive cam threads” and “driven cam threads” refer to components and features of embodiments of axial linkages in accordance herewith. For example, the terms “drive cam body” and “driven cam body” are intended to be understood in the sense that the “drive” cam body applies load to (i.e., “drives”) the “driven” cam body. The relative motions and forces of the mechanisms described herein can be inverted or reversed without departing from the intended meaning and scope of the present disclosure.

[0035] As used herein, the term “fluid-powered” refers to the use of fluid pressure to generate forces acting on an axial linkage to perform one or more selected functions, such as (by way of non-limiting example) linkage extension, linkage retraction, and linkage latching.

[0036] As used herein, the terms “unlatch” and “re-latch” refer, respectively, to the actions of allowing or preventing axial separation of mating components resulting from the application of axial load or torsion through the linkage assembly. The term “latched position” refers to the state of the linkage assembly in which the component in question is latched. The term “unlatched state” refers to any position where the linkage is not in the “latched position”.

[0037] As used in this disclosure, the term “thread” denotes a threaded connection formed by the engagement of mating respective threadforms on two coaxial components, and references to “movement” of a thread are to be understood as denoting relative rotation and consequent axial displacement of the two coaxial components.

[0038] As used herein, the term “non-jamming” is to be understood as meaning that when a thread stop is engaged due to the application of axial load, fluid pressure, and / or torque in a first direction, the thread stop will freely disengage if the direction of the applied load is reversed.

[0039] Fluid-Powered Latching Axial Linkage

[0040] In one exemplary and non-limiting embodiment, a fluid-powered latching axial linkage in accordance with the present disclosure comprises a drive cam body, an intermediate cam body, a driven cam body, and fluid actuation means, wherein:

[0041] • the drive cam body and the intermediate cam body are threadingly engaged via a nonself-locking drive thread having a drive thread threadform and a drive thread lead angle;

[0042] • the intermediate cam body and the driven cam body are threadingly engaged via a nonself-locking driven thread having a driven thread threadform and a driven thread lead angle; • a selected one of the drive thread and the driven thread is a left-handed thread;

[0043] • the non-selected one of the drive thread and the driven thread is a right-handed thread; and

[0044] • the fluid actuation means is configured to transmit axial load between the drive cam body and the driven cam body.

[0045] In a first variant embodiment, the fluid actuation means comprises a single linear fluid actuator comprising:

[0046] • a cylinder assembly; and

[0047] • a piston axially movable within an annular piston chamber formed within the cylinder, with the piston chamber defining: o a variable- volume retraction fluid chamber on a selected side of the piston; and o a variable-volume extension fluid chamber on a side of the piston opposite the selected side of the piston.

[0048] The drive cam body, the intermediate cam body, and the driven cam body are coaxially disposed within an axial bore of the piston. The piston chamber defines a variable-volume extension fluid chamber above the piston, and a variable-volume retraction fluid chamber below the piston, such that:

[0049] • when a fluid pressure in the extension fluid chamber is greater than a fluid pressure in the retraction fluid chamber, the fluid actuator will urge the axial linkage to extend in length; and

[0050] • when the fluid pressure in the extension fluid chamber is less than a fluid pressure in the retraction fluid chamber, the fluid actuator will urge the axial linkage to reduce in length.

[0051] The lead angles and threadforms of the drive thread and the driven thread are selected taking frictional properties into consideration as appropriate, such that axial load resulting from externally- applied fluid pressure in the extension and retraction fluid chambers and / or externally- applied axial loads transmitted through the linkage will urge the intermediate cam body to rotate, and thus cause the overall length of the linkage to increase or decrease depending on the direction of the axial load. Thus, the drive thread and the driven thread are both non-self-locking. The latching axial linkage incorporates a drive thread stop means (or simply “drive thread stop”) acting between the drive cam body and the intermediate cam body, and configured to be non-jamming and to limit the amount of rotation of the drive thread in a selected rotational direction (i.e., clockwise or counter-clockwise). The drive thread stop means may be provided (for example) by providing abutment elements on the drive cam body and the intermediate cam body, which abutments, when in contact with each other in response to relative rotation of the drive cam body and the intermediate cam body in a given direction, will prevent further such relative rotation.

[0052] Similarly, the latching axial linkage incorporates a driven thread stop means (or simply “driven thread stop”) acting between the intermediate cam body and the driven cam body, and configured to be non-jamming and to limit the amount of rotation of the driven thread in the nonselected rotational direction (i.e., the rotational direction opposite to the selected rotational direction). The driven thread stop means may be provided (for example) by providing abutment elements on the intermediate cam body and the driven cam body, which abutments, when in contact with each other in response to relative rotation of the intermediate cam body and the driven cam body in a given direction, will prevent further such relative rotation.

[0053] The latching axial linkage is operable between a latched position in which relative axial and relative rotational movements between the drive cam body and the driven cam body are prevented, and unlatched positions in which relative rotational movement between the drive cam body and the driven cam body is enabled. Relative axial movement between the drive cam body and the driven cam body may also be enabled in unlatched positions depending on a user-selected fluid control system for the linear fluid actuator.

[0054] The latching axial linkage uses a control system configured to direct a control-system actuating fluid to effect desired changes in the volumes of the extension chamber and retraction chamber, consequently enabling or preventing the extension of the fluid-powered latching axial linkage, as the desired case may be. More specifically, the control system is operable between:

[0055] (a) a first state (alternatively, the “hold” state) in which the piston does not move, such that the volumes of the extension chamber and retraction chamber are prevented from changing. (b) a second state (alternatively, the “extend” state) in which the piston is urged toward an unlatched state such that: o the volume of the extension fluid chamber (i.e., above the piston) is allowed to increase; and o the volume of the retraction fluid chamber (i.e., below the piston) is allowed to decrease; and

[0056] (c) a third state (alternatively, the “retract” state) in which the piston is urged toward the latched position; o the volume of the extension fluid chamber is allowed to decrease; and o the volume of the retraction fluid chamber is allowed to increase;

[0057] The latching axial linkage is configurable to act between the main body and the gripping assembly of a gripping tool. Lead angles and threadforms of the drive thread and the driven thread are selected such that fluid pressure applied to the retraction fluid chamber will urge the axial linkage towards its “latched” position and retain the gripping elements of the tool in their retracted position. Similarly, fluid pressure applied to the extension fluid chamber will urge the axial linkage away from its “latched” position and drive engagement of the gripping elements of the gripping assembly with a tubular workpiece. Furthermore, bi-rotary movement of the load adaptor with torque through the drive cam body, intermediate cam body and driven cam body to the tubular workpiece will tend to increase the radial load between the gripping elements and the tubular workpiece.

[0058] To facilitate fluid-powered extension and retraction of the axial linkage, the frictional resistance to rotation of the drive thread and the driven thread may be decreased by decreasing the angles of the tension and compression flanks of the threadform of each thread (relative to the radial plane of each thread). Asymmetric threadforms may be selected, with the angle of the tension flanks differing in magnitude from the angle of the compression flanks, to bias the resistance to rotation in a selected direction of axial load resulting from fluid pressure.

[0059] To facilitate fluid-powered extension and retraction of the axial linkage, the frictional resistance to rotation may be decreased by decreasing the angle of the tension and compression flanks (relative to the radial plane of the drive thread) of the threadform of the drive thread. Accordingly, asymmetric threadforms may be selected with the angle of the tension flanks differing in magnitude from the angle of the compression flanks to bias the resistance to rotation in a selected direction of axial load resulting from fluid pressure.

[0060] In a second variant embodiment, the fluid actuation means may be provided by a plurality of fluid actuators coupled circumferentially about the drive cam body, intermediate cam body, and driven cam body.

[0061] Fluid-Powered Latching Axial Linkage with Fluid Signalling System

[0062] In another exemplary and non-limiting embodiment in accordance with the present disclosure, a fluid-powered latching axial extension linkage according to the above-described first variant embodiment is incorporated into a casing running tool (CRT), with the cylinder of the linear fluid actuator axially coupled to the drive cam body, with the piston axially coupled to the driven cam body, with the drive cam body rigidly mounted to a mandrel of the CRT, and with the driven cam body rigidly mounted to or integral with a cage of a gripping assembly of the CRT.

[0063] The CRT comprises a bumper assembly having a bumper base rigidly mounted to the cage, and a bumper plate axially translatable relative to the bumper base in response to contacting engagement with a tubular workpiece. The CRT is configured with a fluid signalling system comprising one or more fluid directional control valves (alternatively referred to herein as simply “signal valves”), a valve carrier, and a valve bumper, wherein:

[0064] (a) each signal valve is configured to direct the flow of a signalling-system actuating fluid in response to selected triggering event (alternatively, simply “trigger”) to provide a signal indicative of a selected operational state of the linkage and / or the CRT;

[0065] (b) the valve carrier is rotationally coupled to the cylinder, while also being axially constrained to a bumper base of a CRT bumper assembly so as to be axially translatable relative to the cylinder when the axial linkage is unlatched; and

[0066] (c) the valve bumper is rotationally coupled to the valve carrier, while also being axially constrained to a bumper plate of a CRT bumper assembly so as to be axially translatable relative to the valve carrier in response to the tubular workpiece contacting the bumper plate.

[0067] In accordance with the present disclosure, non-limiting examples of selected triggers include tubular-to-CRT contact and axial linkage position. For example: o a first signal valve (alternatively, “set-down signal valve”) may be mounted to the valve carrier, so as to contactingly engage the valve bumper when a tubular workpiece applies compressive axial force to the CRT bumper assembly, and to disengage from the valve bumper when a tubular workpiece disengages from the bumper plate; and / or o a second signal valve (alternatively, “extension signal valve”) may be mounted to the cylinder, so as to contactingly engage the valve carrier when the axial linkage is latched, and to disengage from the valve carrier when axial linkage is unlatched.

[0068] BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Embodiments in accordance with the present disclosure will now be described with reference to the accompanying Figures, in which numerical references denote like parts, and in which:

[0070] FIGURE 1 is a cross-section through a prior art axial linkage incorporated in a prior art internally-gripping casing running tool (CRTi), substantially corresponding to the CRTi shown in Figure 5A in US 11,560,761.

[0071] FIGURE 2A and 2B, respectively, are elevation and cross-section views of the prior art axial linkage in FIG. 1, substantially corresponding to the linkage shown in Figures 5B and 5C in US 11,560,761.

[0072] FIGURE 3 is a graphical representation of a portion of the operating range of the prior art axial linkage in FIG. 2 A and 2B.

[0073] FIGURE 4 is a graphical representation of a portion of the operating range of an axial linkage in accordance with the present disclosure. FIGURE 5 is a cross-section through a first embodiment of an axial linkage assembly in accordance with the present disclosure, shown incorporated in a prior art CRT.

[0074] FIGURE 6A is a schematic diagram illustrating an exemplary fluid control system in the “hold” state.

[0075] FIGURE 6B is a schematic diagram illustrating an exemplary fluid control system in the “extend” state.

[0076] FIGURE 6C is a schematic diagram illustrating an exemplary fluid control system in the “retract” state.

[0077] FIGURE 7A and 7B, respectively, are cross-sectional and partially-sectioned views of the axial linkage assembly in FIG. 5, shown in the latched position, with the fluid control system in the “hold” state.

[0078] FIGURE 8A and 8B, respectively, are cross-sectional and partially-sectioned views of the linkage assembly in FIG. 5, shown in an unlatched state, with the fluid control system in the “extend” state pressurizing the extension fluid chamber of the axial linkage assembly.

[0079] FIGURE 9A and 9B, respectively, are cross-sectional and partially-sectioned views of the axial linkage in FIG. 7, with the axial linkage shown after right-hand rotation of the drive cam body relative to the driven cam body until the driven thread stop is engaged, and with the axial length of the linkage unchanged.

[0080] FIGURE 10A and 10B, respectively, are cross-sectional and partially- sectioned views of the axial linkage in FIG. 7, with the axial linkage shown after left-hand rotation of the drive cam body relative to the driven cam body until the drive thread stop being engaged, with the axial length of the linkage unchanged. FIGURE 11A and 11B, respectively, are cross-sectional and partially-sectioned views of the linkage assembly in FIG. 5, shown in an unlatched state, with the fluid control system in the “retract” state pressurizing the retraction fluid chamber of the axial linkage assembly.

[0081] FIGURE 12 is a cross-section through a second embodiment of an axial linkage assembly in accordance with the present disclosure, configured with a fluid signalling system and incorporated in a prior art CRT.

[0082] FIGURE 13A is an isometric view of a CRT configured with an axial linkage and fluid signalling system as in FIG. 12, with the fluid signal system incorporating an extension signal valve and a set-down signal valve, and with the axial linkage shown in the latched position without tool-to-tubular contact.

[0083] FIGURE 13B is a schematic diagram for the fluid signalling system of the CRT configuration shown in FIG. 13 A.

[0084] FIGURE 14A is an isometric view of the CRT shown in FIG. 13 A, with the axial linkage shown in the latched position with tool-to-tubular contact.

[0085] FIGURE 14B is a schematic diagram for the fluid signalling system for the CRT configuration shown in FIG. 14A.

[0086] FIGURE 15A is an isometric view of the CRT shown in FIG. 13A, with the axial linkage shown in an unlatched state with tool-to-tubular contact.

[0087] FIGURE 15B is a schematic diagram for the fluid signalling system for the CRT configuration shown in FIG. 15 A.

[0088] FIGURE 16A is an isometric view of a CRT configured with an axial linkage and fluid signalling system as in FIG. 12, with the fluid signal system incorporating only a set-down signal valve, and with the axial linkage shown in the latched position, without tool-to-tubular contact.

[0089] FIGURE 16B is a schematic diagram for the fluid signalling system for the CRT configuration shown in FIG. 16A. FIGURE 17A is an isometric view of the CRT shown in FIG. 16A, with the axial linkage shown in the latched position, with tool-to-tubular contact.

[0090] FIGURE 17B is a schematic diagram for the fluid signalling system for the CRT configuration shown in FIG. 17A.

[0091] FIGURE 18A is an isometric view of a CRT configured with an axial linkage and fluid signalling system as in FIG. 12, with the fluid signalling system incorporating only an extension signal valve, and with the axial linkage shown in the latched position.

[0092] FIGURE 18B is a schematic diagram for the fluid signalling system for the CRT configuration shown in FIG. 18 A.

[0093] FIGURE 19A is an isometric view of a variant of the the CRT shown in FIG. 18A, with the axial linkage shown in an unlatched state.

[0094] FIGURE 19B is a schematic diagram for the fluid signalling system for the CRT configuration shown in FIG. 19A.

[0095] DETAIEED DESCRIPTION

[0096] Prior Art Axial Extension Linkage

[0097] FIG. 1 is a cross-section through a prior art axial extension linkage 200, installed in a prior art internally-gripping CRT 100, substantially corresponding to the CRTi shown in FIG. 5A in US 11,560,761.

[0098] CRT 100 comprises:

[0099] • a main body assembly 110;

[0100] • a gripping assembly 120; and

[0101] • a prior art axial extension linkage 200 which comprises a mechanical latch assembly.

[0102] The upper end of main body assembly 110 is provided with a load adaptor 111, illustrated by way of non-limiting example as having a conventional rotary shouldered connection 112 for structural connection to a top drive quill (not shown) of a top-drive-equipped drilling rig (not shown). Gripping assembly 120 comprises a land surface 122 that is carried by a bumper 121 attached to a cage 123, and grip surfaces 124 that are carried by, and axially and rotationally linked to, cage 123. CRT 100 is shown in as it would appear in the latched position. In this latched position, relative axial movement between main body assembly 110 and gripping assembly 120 is prevented by axial extension linkage 200, such that gripping assembly 120 is held in its retracted position.

[0103] FIG. 2A and 2B, respectively, are elevation and cross-section views of prior art axial extension linkage 200 with a mechanical latching assembly, shown in the latched position, substantially corresponding to the linkage shown in FIGS. 5B and 5C in US 11,560,761, configured for installation in a CRT 100 as in FIG. 1.

[0104] Prior art axial extension linkage 200 comprises:

[0105] • a drive cam body 210;

[0106] • an intermediate cam body 220;

[0107] • a driven cam body 230;

[0108] • a drive thread stop 203;

[0109] • a driven thread stop 204;

[0110] • a latch body 240; and

[0111] • a striker body 250.

[0112] Drive cam body 210 and intermediate cam body 220 are threadingly engaged via a drive thread

[0113] 201 comprising an external multi-start thread 211 on drive cam body 210 engaging an internal multi-start thread 221 on intermediate cam body 220. Drive thread 201 acts to translate righthand rotation of drive cam body 210 relative to intermediate cam body 220 into axial extension of axial extension linkage 200. Intermediate cam body 220 and driven cam body 230 are threadingly engaged via a driven thread 202 comprising an external multi-start thread 222 on intermediate cam body 220 engaging an internal multi- start thread 231 on driven cam body 230 and acting in opposition to drive thread 201. When axial linkage 200 is unlatched, driven thread

[0114] 202 acts to translate left-hand rotation of intermediate cam body 220 relative to driven cam body 230 into axial extension of axial extension linkage 200. The lead angles of drive thread 201 and driven thread 202 are selected such that axial load transmitted through linkage 200 will urge intermediate cam body 220 to rotate, and thereby cause the length of linkage 200 to change when linkage 200 is unlatched.

[0115] Drive thread stop 203 acts between drive cam body 210 and intermediate cam body 220 to limit the range of travel of drive thread 201 when drive cam body 210 is rotated in the lefthand direction relative to intermediate cam body 220. Driven thread stop 204 acts between intermediate cam body 220 and driven cam body 230 to limit the range of travel of driven thread 202 when intermediate cam body 220 is rotated in the right-hand direction relative to driven cam body 230. Both drive thread stop 203 and driven thread stop 204 are configured to be nonjamming.

[0116] Latch body 240 is carried by intermediate cam body 220 and is axially slidingly movable relative to intermediate cam body 220 between a first (or “latching”) position and a second (or “free”) position.

[0117] Axial extension linkage 200 is considered to be “latched” and in its “latched position” when:

[0118] • latch body 240 is matingly engaged with striker body 250, which requires that: o latch body 240 is in its latching position; o striker body 250 is in its latching position; and o driven thread 202 is axially positioned at the limit of its operating range, as defined by engagement of driven thread stop 204; and

[0119] • drive cam body 210 is in its latching position, holding latch body 240 in its latching position.

[0120] Axial extension linkage 200 is considered to be “unlatched” and in an “unlatched position” when any one of the above conditions is not met.

[0121] FIG. 3 is a graphical representation of a portion of the operating range of a prior art axial extension linkage 200, substantially similar to the linkage shown in FIG. 4 in US 11,560,761. The “makeup ramp” line corresponds to the drive thread lead, and the “breakout ramp” line corresponds to the driven thread lead, of linkage 200. Axial linkage 200 may be re-latched following any operational sequence that ends at the latched position. A few exemplary operational sequences are indicated by the arrows labeled “Re-latch” in FIG. 3.

[0122] When axial linkage 200 is latched, relative rotation between intermediate cam body 220 and driven cam body 230 is prevented by engagement of latch body 240 with striker body 250. To prevent unintentional unlatching of prior art axial extension linkage 200 when used in CRT 100, drive thread 201 must be designed to be self-locking: the lead angle and the tension flank angle of drive thread 201 must be selected such that relative rotation between drive cam body 210 and intermediate cam body 220 urged by (pure) axial tension transmitted through drive thread 201 is prevented by friction within drive thread 201.

[0123] CRT With Fluid-Powered Latching Axial Linkage

[0124] FIGS. 5-1 IB illustrate an exemplary and non-limiting embodiment 1000 of a casing running tool (CRT) incorporating a fluid-powered latching axial linkage in accordance with the present disclosure. CRT 1000 is generally similar to prior art CRT 100 shown in FIG. 1, having a longitudinal axis X and comprising a main body assembly 1100 and a gripping assembly 1200, with the addition of an axial linkage 1300 and a linear fluid actuator 1400. The upper end of main body assembly 1100 is provided with a lock sleeve 1130 and a load adaptor 1110, illustrated by way of non-limiting example as having a conventional rotary shouldered connection 1120 for structural connection to a top drive quill (not shown) of a top-drive-equipped drilling rig (not shown).

[0125] Gripping assembly 1200 comprises:

[0126] • a cage 1230;

[0127] • a bumper base 1250 attached to cage 1230

[0128] • a bumper plate 1210 carried by bumper base 1250 and having a land surface 1220; and

[0129] • gripping elements 1240 that are carried by, and axially and rotationally linked to, cage 1230. In this non-limiting exemplary embodiment, bumper plate 1210 may rotate around longitudinal axis X relative to cage 1230. Gripping elements 1240 of gripping assembly 1200 are configured to engage the inside surface of a tubular workpiece 1001.

[0130] Axial linkage 1300 comprises:

[0131] • a drive cam body 1310;

[0132] • an intermediate cam body 1320; and

[0133] • a driven cam body 1330;

[0134] Fluid actuator 1400 comprises:

[0135] • a cylinder assembly 1410 comprising: o an upper housing 1411; o a lower housing 1412; and o an upper bearing retainer 1413 threadingly engageable with upper housing 1411; and

[0136] • a piston assembly 1420 comprising: o a generally cylindrical piston 1421 having an axial piston bore 1423 defined by a piston bore wall 1424, with piston 1421 being axially movable within a piston chamber 1450 defined by upper housing 1411 and lower housing 1412 of cylinder assembly 1410; and o a piston extension ring 1422, which is shown by way of non-limiting example, as threadingly engaging piston 1421.

[0137] Piston assembly 1420 is axially coupled to driven cam body 1330 by a lower bearing element 1360, and cylinder assembly 1410 is axially coupled to drive cam body 1310 by an upper bearing element 1370.

[0138] Drive cam body 1310 is carried by main body assembly 1100, and is linked to load adaptor 1110 so as to be generally fixed against rotation and axial movement relative to load adaptor 1110. Driven cam body 1330 is carried by gripping assembly 1200, and is linked to or incorporated into cage 1230 so as to be generally fixed against rotation and axial movement relative to cage 1230. CRT 1000 is shown in FIG. 5 as it would appear in the latched position where the relative axial position between main body assembly 1100 and gripping assembly 1200 is maintained by fluid actuator 1400, such that gripping assembly 1200 is held in its retracted position.

[0139] The fluid-powered latching axial linkage (i.e., 1300 with 1400) is actuated by a control system 1500 which, by way of non-limiting example, is configured with:

[0140] • a control system directional control valve 1510 that directs the flow of an controlsystem actuating fluid;

[0141] • a pump 1520 that pressurizes the control- system actuating fluid;

[0142] • an ambient-pressure fluid reservoir 1530;

[0143] • an extension fluid chamber line 1540; and

[0144] • a retraction fluid chamber line 1550.

[0145] An exemplary control system 1500 is schematically illustrated in FIGS. 6A-6C. The volume within fluid actuator 1400 above piston 1421 is referred to as an extension fluid chamber 1401, and the volume below piston 1421 is referred to as a retraction fluid chamber 1402. Control system 1500 is used to direct fluid to effect changes in the volumes of extension fluid chamber 1401 and retraction fluid chamber 1402, consequently enabling or preventing the extension of the axial linkage 1300.

[0146] Control system directional control valve 1510 is illustrated, by way of non-limiting example, as having a four-way / three-position configuration, comprising:

[0147] • an input port P,

[0148] • an output port If;

[0149] • a first direction port A ; and

[0150] • a second direction port B.

[0151] FIG. 6A illustrates control system 1500 in the “hold” state wherein control system directional control valve 1510 is configured to prevent flow of control-system actuating fluid in or out of both extension fluid chamber 1401 and retraction fluid chamber 1402.

[0152] FIG. 6B illustrates control system 1500 in the “extend” state wherein control system directional control valve 1510 is configured to direct pressurize control-system actuating fluid from the pump 1520 to extension fluid chamber 1401 and to direct control- system actuating fluid from retraction fluid chamber 1402 to fluid reservoir 1530.

[0153] FIG. 6C illustrates control system 1500 in the “retract” state wherein control system directional control valve 1510 is configured to direct pressurize control-system actuating fluid from pump 1520 to retraction fluid chamber 1402 and to direct control- system actuating fluid from extension fluid chamber 1401 to fluid reservoir 1530.

[0154] FIGS. 7A and 7B, respectively, are cross-sectional and partially- sectioned views of axial linkage 1300 and fluid actuator 1400, shown in the latched position. The inner race of lower bearing element 1360 is retained on driven cam body 1330 by a lower bearing internal washer 1341 and a lower bearing external retainer 1340 installed on driven cam body 1330. The outer race of lower bearing element 1360 is retained on piston extension ring 1422 by a lower bearing external washer 1351 and a lower bearing internal retainer 1350 installed on piston extension ring 1422. The inner race of upper bearing element 1370 is retained on drive cam body 1310 by lock sleeve 1130, which is mounted to drive cam body 1310 with threaded fasteners. The outer race of upper bearing element 1370 is retained on upper housing 1411 by upper bearing retainer 1413, which threadingly engages upper housing 1411.

[0155] Piston 1421 is slidingly translatable within piston chamber 1450 of fluid actuator 1400. The volume within piston chamber 1450 above piston 1421 is the extension fluid chamber 1401, and the volume within piston chamber 1450 below piston 1421 is the retraction fluid chamber 1402. Extension fluid chamber 1401 has an extension chamber fluid port 1403 where controlsystem actuating fluid may enter or exit, and retraction fluid chamber 1402 has a retraction chamber fluid port 1404 where control-system actuating fluid may enter or exit.

[0156] Drive cam body 1310 and intermediate cam body 1320 are threadingly engaged via a drive thread 1301 comprising an external multi-start thread 1311 on drive cam body 1310 engaging an internal multi-start thread 1321. Drive thread 1301 acts to translate right-hand rotation of drive cam body 1310 relative to intermediate cam body 1320 into axial extension of axial linkage 1300. Intermediate cam body 1320 and driven cam body 1330 are threadingly engaged via a driven thread 1302 comprising an external multi-start thread 1322 on intermediate cam body 1320 engaging an internal multi-start thread 1331 on driven cam body 1330, and acting in opposition to drive thread 1301. Driven thread 1302 acts to translate left-hand rotation of intermediate cam body 1320 relative to driven cam body 1330 into axial extension of axial linkage 1300.

[0157] Drive thread stops 1303, provided by drive cam body abutments 1312 and intermediate cam body abutments 1323, act between drive cam body 1310 and intermediate cam body 1320 to limit the range of travel of drive thread 1301 when drive cam body 1310 is rotated in the lefthand direction relative to intermediate cam body 1320. Driven thread stops 1304, provided by driven cam body abutments 1332 and intermediate cam body abutments 1324, act between intermediate cam body 1320 and driven cam body 1330 to limit the range of travel of driven thread 1302 when intermediate cam body 1320 is rotated in the right-hand direction relative to driven cam body 1330. Both drive thread stop 1303 and driven thread stop 1304 are configured to be non-jamming.

[0158] The lead angles of drive thread 1301 and driven thread 1302 are selected such that axial load transmitted through linkage 1300 will urge intermediate cam body 1320 to rotate and thereby cause the length of linkage 1300 to change. Both drive thread 1301 and driven thread 1302 are configured to be individually non-self-locking in response to both axial tension and axial compression loads.

[0159] FIG. 4 is a graphical representation of a portion of the operating range of a first exemplary and non-limiting embodiment of an axial linkage 1300 with fluid actuator 1400 in accordance with the present disclosure. The makeup ramp line corresponds to the drive thread lead, and the breakout ramp line corresponds to the driven thread lead, of linkage 1300. Compared to the operating range of axial linkage 200 shown in FIG. 3, the makeup ramp angle (i.e., the lead of drive thread 1301) of axial linkage 1300 is selected to be steeper such that drive thread 1301 is not self-locking. Axial linkage 1300 can be re-latched by following any operational sequence that ends at the latched position within the exemplary re-latch limit shown in FIG. 4, which in this embodiment corresponds to a position that is sufficiently axially retracted that gripping element 1240 in FIG. 5 is disengaged from tubular workpiece 1001. A few exemplary operational sequences are also indicated by the arrows labeled “Re-latch” in FIG. 4. When both drive thread 1301 and driven thread 1302 are configured to be non-self-locking, axial compressive load applied through drive cam body 1310, intermediate cam body 1320, and driven cam body 1330 will urge axial linkage 1300 toward the latched position starting from any location in the operating range.

[0160] In the latched position shown in FIGS. 7A and 7B, fluid control system 1500 is typically positioned in the “hold” state, illustrated schematically in FIG. 6A, holding the linkage in the latched position. Axial linkage 1300 is retracted to its minimum axial extension, and both drive thread stop 1303 and driven thread stop 1304 are engaged.

[0161] FIGS. 8A and 8B, respectively, are cross-sectional and partially- sectioned views of axial linkage 1300 and fluid actuator 1400 shown in an unlatched state. Axial linkage 1300 does not require rotation of load adapter 1110 relative to gripping assembly 1200 as required for CRTs using prior art linkages. Consequently, because drive cam body 1310 is carried by main body assembly 1100, and driven cam body 1330 is carried by gripping assembly 1200, no relative rotation occurs between drive cam body 1310 and driven cam body 1330.

[0162] Referencing FIG. 5, when linkage 1300 is unlatched during normal operation of CRT 1000, extension of axial linkage 1300 is limited by gripping elements 1240 of gripping assembly 1200 contacting the inside surface of tubular workpiece 1001. Fluid control system 1500 is typically positioned in the “extend” state, illustrated schematically in FIG. 6B, to initially set gripping elements 1240 against tubular workpiece 1001. Pressurized control- system actuating fluid from pump 1520 is directed to extension fluid chamber 1401 and control- system actuating fluid from retraction fluid chamber 1402 is directed to fluid reservoir 1530 as indicated by the direction of fluid flow arrows F in FIG. 8B. Axial stroking of piston 1421 within the bore of fluid actuator 1400 causes the length of linkage 1300 to change, and causes intermediate cam body 1320 to rotate relative to one or both of drive cam body 1310 and driven cam body 1330. The axial position of intermediate cam body 1320 is shown, by way of non-limiting example, in FIGS. 8 A and 8B as being between drive cam body 1310 and driven cam body 1330, with drive thread stop 1303 and driven thread stop 1304 disengaged. As would be apparent to persons skilled in the art, the position of intermediate cam body 1320 relative to drive cam body 1310 and driven cam body 1330 depends on the length of axial linkage 1300 and the selected helix angles of drive thread 1301 and driven thread 1302. FIGS. 9A and 9B, respectively, are cross-sectional and partially- sectioned views of axial linkage 1300 and fluid actuator 1400. Pressurized fluid from pump 1520 is directed to extension fluid chamber 1401 by fluid control system 1500 positioned in the “extend” state, illustrated schematically in FIG. 6B. FIGS. 9A and 9B show axial linkage 1300 after right-hand rotation of drive cam body 1310 relative to driven cam body 1330 (as may be understood with reference to rotational position indicator / ) shown for illustrative purposes on lock sleeve 1130 in FIGS. 7B, 8B, 9B, 10B, and 11B), with no change in length of axial linkage 1300, and with no rotation of driven cam body 1330, which is constrained by the engagement of gripping assembly 1200 with tubular workpiece 1001. Drive cam body 1310 moves relative to intermediate cam body 1320 along the path defined by drive thread 1301, and intermediate cam body 1320 simultaneously moves relative to driven cam body 1330 along the path defined by driven thread 1302. At the operational position shown in FIGS. 9A and 9B, driven thread stop 1304 between intermediate cam body 1320 and driven cam body 1330 is engaged. Any further right-hand rotation of drive cam body 1310 relative to driven cam body 1330 will be translated into additional axial extension of linkage 1300 and thus will increase the radial gripping force between gripping elements 1240 and tubular workpiece 1001. Relative rotation between drive cam body 1310 and driven cam body 1330 may be achieved by rotation of load adapter 1110 relative to gripping assembly 1200.

[0163] FIGS. 10A and 10B, respectively, are cross-sectional and partially- sectioned views of axial linkage 1300 and fluid actuator 1400. Pressurized fluid from pump 1520 is directed to extension fluid chamber 1401 by fluid control system 1500 positioned in the “extend” state, illustrated schematically in FIG. 6B. FIGS. 10A and 10B show axial linkage 1300 after left-hand rotation of drive cam body 1310 relative to driven cam body 1330, (as may be understood with reference to rotational position indicator / ) shown for illustrative purposes on lock sleeve 1130 in FIGS. 7B, 8B, 9B, 10B, and 11B), with no change in length of axial linkage 1300, and with no rotation of driven cam body 1330, which is constrained by the engagement of gripping assembly 1200 with tubular workpiece 1001. Drive cam body 1310 moves relative to intermediate cam body 1320 along the path defined by drive thread 1301, and intermediate cam body 1320 simultaneously moves relative to driven cam body 1330 along the path defined by driven thread 1302. At the operational position shown in FIGS. 10A and 10B, drive thread stop 1303 between drive cam body 1310 and intermediate cam body 1320 is engaged. Any further left-hand rotation of drive cam body 1310 relative to driven cam body 1330 would be translated into additional axial extension of linkage 1300 and thus will increase the radial gripping force between gripping elements 1240 and tubular workpiece 1001.

[0164] FIGS. 11A and 11B, respectively, are cross-sectional and partially- sectioned views of axial linkage 1300 and fluid actuator 1400 shown in an unlatched state moving towards the latched position shown in FIGS. 7A and 7B. Fluid control system 1500 is typically positioned in the “retract” state, illustrated schematically in FIG. 6C, to disengage gripping elements 1240 from tubular workpiece 1001. Pressurized control-system actuating fluid from pump 1520 is directed to retraction fluid chamber 1402 and control- system actuating fluid from extension fluid chamber 1401 is directed to fluid reservoir 1530 as indicated by the direction of fluid flow arrows F in FIG. 1 IBThe axial position of intermediate cam body 1320 is shown, by way of non-limiting example, in FIGS. 11A and 11B as being between drive cam body 1310 and driven cam body 1330, with drive thread stop 1303 disengaged and driven thread stop 1304 engaged. As would be apparent to persons skilled in the art, the position of intermediate cam body 1320 relative to drive cam body 1310 and driven cam body 1330 depends on the length of axial linkage 1300 and the selected helix angles of drive thread 1301 and driven thread 1302.

[0165] CRT With Fluid-Powered Latching Axial Linkage with Fluid Signalling System

[0166] FIGS. 12-15B illustrate an exemplary and non-limiting embodiment of an accessory fluid signalling system 2100 incorporated with an axial linkage 1300 and a fluid actuator 1400 in accordance with the present disclosure. FIG. 12 is a longitudinal cross-section through a CRT 2000 with axial linkage 1300 substantially corresponding to FIG. 5, and incorporating fluid signalling system 2100.

[0167] FIGS. 13A, 14A, and 15A are isometric views of CRT 2000 configured with fluid signalling system 2100, which comprises:

[0168] • a first fluid signal directional control valve 2110 that signals axial linkage extension (alternatively referred to as “extension signal valve 2110”);

[0169] • a second fluid signal directional control valve 2120 that signals bumper set-down load (alternatively referred to as “set-down signal valve 2120”);

[0170] • a valve carrier 2130;

[0171] • a valve bumper 2140; • rotary retention lugs 2150;

[0172] • axial retention lugs 2160;

[0173] • a spring element 2170;

[0174] • a pump 2180 (which optionally may be pump 1520 of control system 1500, in lieu of a separate pump for signalling system 2100); and

[0175] • an ambient- pres sure fluid reservoir 2190 (which optionally may be fluid reservoir 1530 of control system 1500, in lieu of a separate fluid reservoir for signalling system 2100).

[0176] Set-down signal valve 2120 is carried by valve carrier 2130, while extension signal valve 2110 is carried by fluid actuator 1400. Both signal valves 2110 and 2120 are illustrated in the present disclosure, by non-limiting example, as being mechanically activated with an internal return spring K to return the signal valves to their inactivated positions when contact load is not applied.

[0177] Valve bumper 2140 is coaxially and rotationally coupled to valve carrier 2130 by a plurality of rotary retention lugs 2150 which are free to translate axially within the extent of stroke slots (not shown) internal to valve carrier 2130. Valve bumper 2140 is biased toward contact engagement with bumper plate 1210 such as, by way of non-limiting example, by a spring element 2170.

[0178] Valve carrier 2130 is coaxially disposed externally about fluid actuator 1400, and rotationally coupled to fluid actuator 1400 by a plurality of rotary retention lugs 2150 which are free to translate axially within the extent of stroke slots 1414 external to lower housing 1412. Valve carrier 2130 is also axially constrained relative to bumper base 1250 by a plurality of axial retention lugs 2160, but is able to translate axially relative to fluid actuator 1400 when axial linkage 1300 changes length.

[0179] The exemplary schematic fluid signal diagrams in FIGS. 13B, 14B, and 15B illustrate the interaction between typical mechanically-activated three-way, two-position directional control valves 2110 and 2120 in series, each having an input port P, a direction port A, and a drain port R, such that: • a fluid-signalling-system actuating fluid from ambient-pressure fluid reservoir 2190 is pressurized by pump 2180 and directed to input port P of set-down signal valve 2120;

[0180] • direction port A of set-down signal valve 2120 is connected to input port P of extension signal valve 2110;

[0181] • drain ports R of extension signal valve 2110 and set-down signal valve 2120 are connected to ambient-pressure fluid reservoir 2190; and

[0182] • direction port A of extension signal valve 2110 leads to a fluid signal 5 (represented by a “star” symbol), which may indicate the operational state of CRT 2000 and axial linkage 1300 to the operator. Signal 5 may lead to, by way of non-limiting examples, a pressure gauge, an indicating flag, a computer system, or an alarm system.

[0183] The configuration of signal valves 2110 and 2120 in series enables alteration of the fluid flow between signal valves 2110 and 2120, as well as fluid signal S'. For example, the fluid flow could be altered such that direction port A of extension signal valve 2120 (rather than direction port A of extension signal valve 2110) leads to fluid signal S'.

[0184] Pressure at fluid signal S' is observable only when the selected combination of activated directional valves is such that the fluid signal path is uninterrupted from input portP of extension signal valve 2110 to direction port A of extension signal valve 2110.

[0185] Referring to FIG. 13 A, tubular workpiece 1001 is shown not in contact with bumper plate 1210; therefore, bumper plate 1210 is uncompressed, and set-down signal valve 2120 is not mechanically activated. Axial linkage 1300 is in the latched position, wherein extension signal valve 2110 is mechanically activated from contact with valve carrier 2130. FIG. 13B schematically illustrates that the fluid signal is directed to ambient-pressure fluid reservoir 2190, since extension signal valve 2110 is mechanically activated.

[0186] Referring to FIG. 14A, tubular workpiece 1001 is shown contacting bumper plate 1210, thereby axially translating bumper plate 1210 and valve bumper 2140 toward valve carrier 2130 by compressing spring element 2170 to mechanically activate set-down signal valve 2120. Pressurized fluid from pump 2180 flows through set-down signal valve 2120 to input port P of extension signal valve 2110. Axial linkage 1300 remains in the latched position, wherein extension signal valve 2110 is mechanically activated from contact with valve carrier 2130. FIG. 14B schematically illustrates the fluid signal remains directed to ambient-pressure fluid reservoir 2190, since extension signal valve 2110 is mechanically activated.

[0187] Referring to FIG. 15 A, tubular workpiece 1001 remains in contact with bumper plate 1210, and mechanically activates set-down signal valve 2120. Axial linkage 1300 is in an unlatched state, wherein axial stroking of piston 1421 within the bore of fluid actuator 1400 will cause axial linkage 1300 to extend and extension signal valve 2110 to disengage from contact with valve carrier 2130. FIG. 15B schematically illustrates the fluid signal path as being completed from pump 2180 to fluid signal S, since set-down signal valve 2120 is mechanically activated and extension signal valve 2110 is not mechanically activated.

[0188] In a variant embodiment illustrated in FIGS. 16-19, fluid signalling system 2100 may comprise only a single selected one of directional control valves 2110 and 2120.

[0189] Referring to FIGS. 16-17, a single set-down signal valve 2120 may be mounted to valve carrier 2130, so as to contactingly engage valve bumper 2140 when a tubular workpiece 1001 compresses bumper plate 1210, and to disengage from valve bumper 2140 when tubular work piece 1001 disengages from bumper plate 1210.

[0190] FIG. 16A shows tubular workpiece 1001 not in contact with bumper plate 1210, therefore bumper plate 1210 is uncompressed and set-down signal valve 2120 is not mechanically activated, and axial linkage 1300 is in the latched position. FIG. 16B schematically illustrates the fluid signal connected to directional port A of set-down signal valve 2120 as being directed to ambient- pres sure fluid reservoir 2190, since set-down signal valve 2120 is not mechanically activated.

[0191] FIG. 17A shows tubular workpiece 1001 contacting bumper plate 1210, thereby axially translating bumper plate 1210 and valve bumper 2140 toward valve carrier 2130 by compressing spring element 2170 and mechanically activating set-down signal valve 2120. Axial linkage 1300 remains in the latched position. FIG. 17B schematically illustrates the fluid signal path as being completed from pump 2180 to fluid signal S, since set-down signal valve 2120 is mechanically activated. Referring to FIGS. 18-19, a single extension signal valve 2110 may be mounted to fluid actuator 1400, so as to contactingly engage valve carrier 2130 when axial linkage is latched, and disengage from valve carrier 2130 when axial linkage is unlatched.

[0192] FIG. 18A shows axial linkage 1300 in the latched position, wherein extension signal valve 2110 is mechanically activated from contact with valve carrier 2130. FIG. 18B schematically illustrates the fluid signal connected to directional port A of extension signal valve 2110 as being directed to ambient-pressure fluid reservoir 2190, since extension signal valve 2110 is mechanically activated.

[0193] FIG. 19A shows axial linkage 1300 in an unlatched state, wherein axial stroking of piston 1421 within the bore of fluid actuator 1400 causes the length of linkage 1300 to change, which subsequently causes extension signal valve 2110 to disengage from contact with valve carrier 2130. FIG. 19B schematically illustrates the fluid signal path as being completed from pump 2180 to fluid signal S, since extension signal valve 2110 is not mechanically activated.

[0194] # # # # #

[0195] It will be readily appreciated by persons skilled in the art that various modifications to embodiments in accordance with the present disclosure may be devised without departing from the scope of the present teachings, including modifications that use equivalent structures or materials hereafter conceived or developed.

[0196] It is especially to be understood that the scope of the present disclosure is not intended to be limited to described or illustrated embodiments, and that the substitution of a variant of any claimed or illustrated element or feature, without any substantial resultant change in functionality, will not constitute a departure from the intended scope of the disclosure.

[0197] In this patent document, any form of the word “comprise” is to be understood in its non-limiting sense as meaning that any element or feature following such word is included, but elements or features not specifically mentioned are not excluded. A reference to an element or feature by the indefinite article "a" does not exclude the possibility that more than one such element or feature is present, unless the context clearly requires that there be one and only one such element or feature.

[0198] Any use herein of any form of the terms "connect", "engage", "couple", "attach", or any other term describing an interaction between elements is not intended to limit the interaction to direct interaction between the subject elements, and may also include indirect interaction between the elements through secondary or intermediary structure.

[0199] Relational and conformational terms such as (but not limited to) “axial”, “coaxial”, and “asymmetric” are not intended to denote or require absolute mathematical or geometrical precision. Accordingly, such terms are to be understood as denoting or requiring substantial precision only (e.g., “substantially parallel”) unless the context clearly requires otherwise.

[0200] Wherever used in this document, the terms “typical” and “typically” are to be understood and interpreted in the sense of being representative of common usage or practice, and are not intended to be understood or interpreted as implying essentiality or invariability.

[0201] LIST OF DRAWING ELEMENTS

[0202] Label Description

[0203] 100 CRT (casing running tool)

[0204] 110 Main body assembly

[0205] 111 Load adapter

[0206] 112 Threaded connection

[0207] 120 Gripping assembly

[0208] 121 Bumper

[0209] 122 Land surface

[0210] 123 Cage

[0211] 124 Grip surface

[0212] 200 Axial extension linkage

[0213] 201 Drive thread

[0214] 202 Driven thread

[0215] 203 Drive thread stop

[0216] 204 Driven thread stop

[0217] 210 Drive cam body

[0218] 211 External multi-start thread - drive cam body

[0219] 220 Intermediate cam body

[0220] 221 Internal multi-start thread - intermediate cam body

[0221] 222 External multi-start thread - intermediate cam body

[0222] 230 Driven cam body

[0223] 231 Internal multi-start thread - driven cam body

[0224] 240 Latch body

[0225] 250 Striker body

[0226] 1000 CRT (casing running tool) with fluid-powered latching axial linkage

[0227] 1001 Tubular workpiece

[0228] 1100 Main body assembly

[0229] 1110 Load adapter

[0230] 1120 Threaded connection

[0231] 1130 Lock sleeve Label Description

[0232] 1200 Gripping assembly

[0233] 1210 Bumper plate

[0234] 1220 Land surface

[0235] 1230 Cage

[0236] 1240 Gripping element

[0237] 1250 Bumper base

[0238] 1300 Axial linkage

[0239] 1301 Drive thread

[0240] 1302 Driven thread

[0241] 1303 Drive thread stop

[0242] 1304 Driven thread stop

[0243] 1310 Drive cam body

[0244] 1311 External multi-start thread - drive cam body

[0245] 1312 Drive cam body abutments - drive thread stop

[0246] 1320 Intermediate cam body

[0247] 1321 Internal multi-start thread - intermediate cam body

[0248] 1322 External multi-start thread - intermediate cam body

[0249] 1323 Intermediate cam body abutments - drive thread stop

[0250] 1324 Intermediate cam body abutments - driven thread stop

[0251] 1330 Driven cam body

[0252] 1331 Internal multi-start thread - driven cam body

[0253] 1332 Driven cam body abutment - driven thread stop

[0254] 1340 Lower bearing external retainer

[0255] 1341 Lower bearing internal washer

[0256] 1350 Lower bearing internal retainer

[0257] 1351 Lower bearing external washer

[0258] 1360 Lower bearing element

[0259] 1370 Upper bearing element

[0260] 1400 Fluid actuator Label Description

[0261] 1401 Extension fluid chamber

[0262] 1402 Retraction fluid chamber

[0263] 1403 Extension chamber fluid port

[0264] 1404 Retraction chamber fluid port

[0265] 1410 Cylinder assembly

[0266] 1411 Upper housing

[0267] 1412 Lower housing

[0268] 1413 Upper bearing retainer

[0269] 1414 Stroke Slots

[0270] 1420 Piston assembly

[0271] 1421 Piston

[0272] 1422 Piston extension ring

[0273] 1423 Piston bore

[0274] 1424 Piston bore wall

[0275] 1450 Piston chamber

[0276] 1500 Control system

[0277] 1510 Control system directional control valve

[0278] 1520 Pump

[0279] 1530 Reservoir

[0280] 1540 Extension fluid chamber lines

[0281] 1550 Retraction fluid chamber lines

[0282] CRT (casing running tool) with fluid-powered latching axial linkage

[0283] 2000 and fluid signalling system

[0284] 2100 Fluid signalling system

[0285] 2110 Extension signal valve

[0286] 2120 Set-down signal valve

[0287] 2130 Valve carrier

[0288] 2140 Valve bumper Label Description

[0289] 2150 Rotary retention lug

[0290] 2160 Axial retention lug

[0291] 2170 Spring element

[0292] 2180 Pump

[0293] 2190 Reservoir

[0294] A Direction port “A” (of 1510, 2110, or 2120)

[0295] B Direction port “B” of 1510

[0296] D Rotational position indicator

[0297] F Fluid flow direction arrow

[0298] K Internal return spring (in 2110 or 2120)

[0299] P Input port (of 1510, 2110, or 2120)

[0300] R Drain port (of 1510, 2110, or 2120)

[0301] S Fluid signal

[0302] X Longitudinal axis of CRT

Claims

1. WHAT IS CLAIMED IS:

1. An axial linkage comprising:(a) a drive cam body;(b) an intermediate cam body;(c) a driven cam body; and(d) a fluid actuation means; wherein:(e) the drive cam body and the intermediate cam body are threadingly engaged via a non-self-locking drive thread having a drive thread threadform and a drive thread lead angle;(f) the intermediate cam body and the driven cam body are threadingly engaged via a non-self-locking driven thread having a driven thread threadform and a driven thread lead angle;(g) the lead angle and threadform of the drive thread are selected such that axial load transmitted from the drive cam body to the intermediate cam body will urge the intermediate cam body to rotate relative to the drive cam body, and thus cause the overall length of the linkage to increase or decrease depending on the direction of the axial load;(h) the lead angle and threadform of the driven thread are selected such that axial load transmitted from the intermediate cam body to the driven cam body will urge the intermediate cam body to rotate relative to the driven cam body, and thus cause the overall length of the linkage to increase or decrease depending on the direction of the axial load;(i) a selected one of the drive thread and the driven thread is a left-handed thread; j) the non- selected one of the drive thread and the driven thread is a right-handed thread;(k) the linkage comprises a drive thread stop that is configured to be non-jamming and to limit the amount of rotation of the drive thread in a selected rotational direction;(l) the linkage comprises a driven thread stop that is configured to be non-jamming and to limit the amount of rotation of the driven thread in the non-selected rotational direction; and(m) the fluid actuation means is configured to transmit axial load between the drive cam body and the driven cam body.

2. The axial linkage as in Claim 1, wherein:(a) the fluid actuation means comprises a single linear fluid actuator having:• a cylinder assembly defining a piston chamber; and• a piston having an axial piston bore, said piston being axially movably disposed within the cylinder;(b) the piston chamber defines a variable-volume extension fluid chamber above the piston, and a variable- volume retraction fluid chamber below the piston, such that:• when a fluid pressure in the extension fluid chamber is greater than a fluid pressure in the retraction fluid chamber, the fluid actuator will urge the axial linkage to extend in length; and• when the fluid pressure in the extension fluid chamber is less than a fluid pressure in the retraction fluid chamber, the fluid actuator will urge the axial linkage to reduce in length; and(c) the drive cam body, intermediate cam body, and driven cam body are coaxially disposed within the piston bore.

3. The axial linkage as in Claim 2, wherein the fluid actuator is actuated by a control system comprising:(a) a directional control valve configured to direct the flow of a control- system actuating fluid;(b) a pump;(c) an ambient-pressure fluid reservoir;(d) an extension fluid chamber line; and(e) a retraction fluid chamber line.

4. The axial linkage as in Claim 2 or Claim 3, wherein the fluid actuator is coupled to the drive cam body and to the driven cam body by a rotary bearing, such that the fluid actuator is free to rotate relative to the drive cam body and free to rotate relative to the driven cam body.

5. The axial linkage as in Claim 1, wherein the fluid actuation means comprises a plurality of fluid actuators coupled circumferentially about the drive cam body, the intermediate cam body, and the driven cam body.

6. The axial linkage as in any one of Claims 1-5, further comprising:(a) a mandrel of a casing running tool;(b) a gripping assembly of a casing running tool; and(c) a bumper assembly of a casing running tool, said bumper assembly comprising:• a bumper base; and• a bumper plate axially translatable relative to the bumper base by contact with a tubular workpiece; wherein the drive cam body is rigidly coupled to the mandrel, and the driven cam body is rigidly coupled to the gripping assembly.

7. The axial linkage as in Claim 6, further comprising a fluid signalling system, said fluid signalling system comprising one or more signal valves configured to direct the flow of a fluidsignalling-system actuating fluid based on a selected trigger, so as to provide a signal indicative of an operational state of either or both of the axial linkage and the casing running tool.

8. The axial linkage as in Claim 7 wherein:(a) the fluid signalling system further comprises a valve carrier rotationally coupled to the cylinder, while also being axially constrained to the bumper base of the bumper assembly so as to be axially translatable relative to the cylinder when the axial linkage is unlatched; and(b) at least one of the one or more signal valves is configured to direct the signalling- system-actuating fluid in response to axial translation of the valve carrier relative to the cylinder, so as to provide a signal indicative of extension of the linkage.

9. The axial linkage as in Claim 7 or Claim 8 wherein:(a) the fluid signalling system further comprises a valve bumper rotationally coupled to the valve carrier, while also being axially constrained to the bumper plate of the bumper assembly so as to be axially translatable relative to the valve carrier in response to the tubular workpiece contacting the bumper plate; and(b) at least one of the one or more signal valves is configured to direct the signalling- system-actuating fluid in response to axial translation of the valve bumper relative to the valve carrier, so as to provide a signal indicative of the tubular workpiece contacting the bumper plate.

10. The axial linkage as in any one of Claims 7-9 wherein the fluid- signalling- system actuating fluid comprises the control-system actuating fluid.

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