CN116490671A - Variable length axial linkage for a down tube tool - Google Patents

Abstract

An axial linkage acting between a body of a tool for gripping a tubular workpiece and a gripping assembly includes a drive cam body coaxially engaged with an intermediate cam body by a drive thread, the intermediate cam body coaxially engaged with a driven cam body by a driven thread, and the drive thread and the driven thread having opposite orientations. The linkage includes a latch mechanism for preventing relative axial displacement of the drive cam body and the idler cam body. When operating in the unlocked state, the linkage converts bi-directional relative rotation into relative axial movement of the drive cam body and the idler cam body, thereby increasing or decreasing the overall length of the linkage depending on the direction of rotation. Any of a variety of operational sequences may be used to re-latch the linkage.

Description

Variable length axial linkage for a down tube tool

Technical Field

The present disclosure relates generally to tools or devices for gripping tubular workpieces and transmitting axial and torsional loads to the workpiece. In particular, the present disclosure relates to a gripping tool for use in the field of drilling, making and workover with drilling and servicing rigs, such as a casing running tool that may be mounted to a top drive of a rig for gripping a casing string section assembled into, deployed into or removed from a wellbore.

Background

The traditional method of running casing or other tubing string into or out of a well is to use power tongs in conjunction with the hoisting system of the rig. This power tong method allows a string composed of a plurality of pipe sections (or "joints") having mating threaded ends to be assembled by tightening the threaded ends together when added to a string installed in a wellbore to form a threaded connection (i.e., connection "make-up") between successive joints; or conversely removed and broken down (i.e., connect "shackle").

However, the power tong method cannot simultaneously perform other beneficial functions such as rotating, pushing or packing fluid after adding or removing a joint to or from the string and while lowering or raising the string in the wellbore. Running the pipe with power tongs also typically requires someone at a dangerous location, such as on the drill floor, or more importantly, above the drill floor, i.e., at a location commonly referred to as a "stab floor".

The advent of drilling rigs equipped with top drive apparatus, which are equipped with Casing Running Tools (CRTs) to grip the top sub of the casing string and, in some cases, seal between the casing and the top drive casing shaft, has enabled a new method of running casing, especially casing. (it will be understood herein that the term "top drive quill" is generally meant to include a tubular string component that can be attached thereto, the lower end of the tubular string component effectively functioning as an extension of the quill.) various CRT devices have been developed that, when used with a top drive device, are capable of lifting, rotating, pushing, and filling the casing string with drilling fluid while running a tubular, thereby eliminating the limitations associated with power tongs. At the same time, the automation of the gripping mechanism is combined with the inherent advantages of the top drive, reducing the degree of manual involvement required and thus improving safety, compared to conventional power tong down tube processes.

When running casing using power tongs or a CRT, the entire weight of the casing string extending below the rig floor is typically supported by slips provided by the floor while a casing joint ("running joint") is added to or removed from the string. Likewise, make-up torque and break-out torque applied to the running joint must also be reacted by the assembled string; this function is typically provided by slips or backup power tongs, depending on the situation.

Us patent 7,909,120 (Slack) discloses a clamping tool that has been used as a CRT, which tool may be generally summarized as a clamping tool comprising:

a body assembly (or more simply, a body) having a load adapter adapted to connect to a drive head (e.g., a top drive quill);

a clamping assembly carried by the body, the clamping assembly having at least one clamping surface adapted to move from a radially retracted position to a radially extended position in which the clamping surface engages an inner or outer surface of the tubular workpiece when the body is axially displaced in at least one axial direction relative to the clamping surface; and

a linkage acting between the body and the clamping assembly, the linkage converting at least one range of rotational movement in at least one rotational direction into axial movement tending to urge the clamping surface into an engaged position (i.e. clamping a tubular workpiece), and which upon activation applies an axial force that increases with increasing torque and correspondingly activates radial compressive traction engagement of the clamping surface with the workpiece, the rotational movement for activating the linkage being bi-directional, i.e. the load adapter rotating clockwise or counter-clockwise with respect to the clamping surface.

Such clamping tools therefore utilize a mechanically activated clamping mechanism that generates a clamping force in response to activation of an axial stroke of the clamping assembly. Axial travel activation is caused by one or more of the following factors:

the action of an internal spring, which may be an air spring;

gravity;

externally applied axial load; and

externally applied torsional load in the form of right-hand or left-hand torque.

The externally applied axial or torsional load is transferred by the tool from the load adapter of the body to the clamping surface of the clamping assembly in traction engagement with the workpiece. It will be apparent to those of ordinary skill in the art that the utility of this or other similar gripping tool is a function of the workpiece size range (typically expressed in terms of minimum and maximum diameters of a tubular workpiece) that can be adjusted between fully retracted and fully extended gripping surface positions (i.e., radial dimensions and radial travel of the gripping surface) of a given gripping tool. The utility of a given gripping tool can be increased if it can accommodate a greater range of workpiece sizes.

Us patent 8,424,939 (Slack) discloses a gripping tool comprising a three cam linkage with two pairs of cams to translate bi-directional rotation into axial movement having the effect of extending the length of the linkage and thereby drive the axial stroke activation of the gripping assembly of the tool. The axial operating range of such prior art axially extending linkages is limited by the helical ramp acting between the intermediate cam body and the idler cam body. Such prior art linkages also include a mating shackle (or "J-latch" mechanism) that, when engaged, prevents relative axial separation of the drive and idler cams, thereby preventing elongation of the linkage.

Disclosure of Invention

In general, the present disclosure teaches a non-limiting embodiment of a variable length axial linkage for a down tube tool that can provide operational advantages over prior art linkages, such as the linkages disclosed in US 7,909,120 and US 8,424,939, including one or more of the following advantages:

for a tube of given diameter, the axial operating range is greater;

the ability to transfer compressive and tensile axial loads when unlocked (rather than only compressive axial loads when unlocked); and

The ability to re-latch using any of a variety of alternative operational sequences (rather than re-latching only after one particular operational sequence).

Embodiments of the linkage of the present disclosure may be configured for retrofitting into prior art gripping tools, such as, but not limited to, those disclosed in US 7,909,120, to replace prior art linkages therein.

As a matter of convention, the terms "drive cam body" and "idler cam body" and similar "drive cam threads" and "idler cam threads" are used by the present disclosure to provide a naming reference for the components and features of the embodiments of the linkage of the present disclosure. For example, the terms "drive cam body" and "driven cam body" should be understood to mean that a load (or displacement) applied to the drive cam body transfers the load (or displacement) to (i.e., "drives") the driven cam body. This convention is not limiting; rather, the relative movement and forces of the illustrated system may be reversed without departing from the intended meaning and scope of the present disclosure.

In one exemplary embodiment, a variable length axial linkage of the present disclosure includes:

A drive cam body;

an intermediate cam body;

a driven cam body; and

a latch mechanism;

wherein:

the drive cam body and the intermediate cam body are threadably engaged by a drive thread having a primary drive thread stop;

the intermediate cam body and the driven cam body are threadably engaged by a driven thread having a driven thread stop;

the selected one of the driving thread and the driven thread is a left-hand thread;

the unselected one of the driving thread and the driven thread is a right-handed thread;

the lead angle and thread form of the driving and driven threads are selected and friction characteristics are considered appropriately so that the axial load transmitted through the linkage will force the intermediate cam body to rotate and thereby cause the overall length of the linkage to vary within a selected range when the latch mechanism is unlatched;

the primary drive thread stop is configured to be non-blocking and limit the amount of rotation of the drive thread in a selected direction of rotation (i.e., clockwise or counterclockwise); and is also provided with

The primary driven thread stop is configured to be non-blocking and limit the amount of rotation of the driven thread in a non-selected direction of rotation (i.e., a direction of rotation opposite the selected direction of rotation).

Accordingly, the variable length axial linkage of the present disclosure acts between the body of the clamping tool and the clamping assembly to convert bi-directional rotation (i.e., clockwise or counter-clockwise rotation) of the load adapter relative to the clamping surface of the clamping assembly into axial movement to drive axial travel activation of the clamping assembly while still allowing axial travel of the load adapter (relative to the clamping assembly) to also result in activation of the clamping assembly independent of rotation. It will be apparent to those skilled in the art that since such axial movement can only occur in association with rotation of the intermediate cam body, the rate of change of axial movement can be affected by inertia, and thus component inertia must be considered in the context of the applied axial load in a given application to ensure satisfactory response time.

For the purposes of this disclosure, the term "thread" is used to refer to a threaded connection between two coaxial components, and "movement" of the thread is understood to refer to the relative rotation and consequent axial displacement of the two components engaged by the thread.

The term "non-blocking" as used hereinabove and elsewhere in this disclosure should be understood as the thread stop is free to disengage if the applied load is reversed when the thread stop is engaged by the application of an axial load and/or torque in a first direction.

In some embodiments, the latch mechanism may include a J-shaped latch mechanism that, when engaged, prevents relative axial separation of the drive cam and the idler cam, thereby preventing axial length changes of the linkage.

In other embodiments, the latch mechanism may include:

a latch body carried by the intermediate cam body and axially slidable relative thereto between a first (or "latch") position and a second (or "free") position (as described below);

a ram body carried by the driven cam body and axially slidable relative thereto within defined limits; and

a first biasing means acting between the striker body and the follower cam body to bias the striker body towards the "locked" position and into engagement with the latch body.

The term "latch position" with respect to a given component as used above and elsewhere in this disclosure should be understood to mean that the component is "ready to latch," in contrast to the term "latch position" that indicates that the component is latched.

When the drive cam body is moved to a "latched" position relative to the intermediate cam body, mating cam surfaces on the drive cam body and the latch body form a contact sliding engagement to move the latch body to its first (or "latched") position on the intermediate cam body and then retain it in that latched position. The latch body is engageable with the striker body when it is in its latched position on the intermediate cam body. The cam surface allows the latch body to move to its second (or "free") position on the intermediate cam body when the drive cam body is not in its "latched" position relative to the intermediate cam body. The latch body cannot engage the striker body when the latch body is in its free position on the intermediate cam body.

The linkage may also include a second biasing means (e.g., a mechanical spring, as one non-limiting example) to urge the latch body toward its free position on the intermediate cam body.

The latch body has a latch surface configured to matingly engage a latch surface on the striker body. Mating engagement occurs when the latch body is in its latched position, the striker body is in its latched position, and the linkage is axially at the limit of its operating range defined by the engagement of the primary drive thread stop and the primary drive thread stop. The striker body is urged toward its latched position by the first biasing means and is engaged with the latch body.

The latch body and the striker body prevent movement of the follower threads (i.e., they prevent relative movement between the intermediate cam body and the follower cam body) when the latch body and the striker body are in mating engagement. The geometry of the follower thread, the sliding of the striker body on the follower cam body, the mating latching surfaces on the latch body and the striker body, and the force of the first biasing means forcing the striker body into engagement with the latch body may be selected such that the latch body and the striker body disengage, or do not tend to disengage, under a selected combination of axial load and torque applied to the linkage.

The linkage is considered "latched" and in the "latched position" when:

the latch body is in mating engagement with the striker body, which requires:

the o-latch body is in its latched position;

the o-ram body is in its latched position; and is also provided with

o driven threads are axially at the limit of their working range defined by the engagement of the driven thread stop; and is also provided with

The drive cam body is in its latching position, thereby holding the latch body in its latching position.

When any of the above conditions is not met, the linkage is considered "unlocked" and in an "unlocked position".

The linkage may further include a secondary driven thread stop, wherein the shoulder surface on the latch body and the shoulder surface on the driven cam body are configured to form a contact engagement to limit the range of operation of the driven thread in a selected rotational direction when the latch body is in its free position.

The linkage may further include an auxiliary drive thread stop, wherein the shoulder surface on the drive cam body and the shoulder surface on the intermediate cam body are configured to form a contact engagement to limit the range of operation of the drive thread in a non-selected rotational direction.

Prior art gripping tools, such as the one taught in US 7,909,120, may include an internal spring that cooperates with gravity to move the gripping assembly toward engagement with the workpiece. When the linkage of the present disclosure is configured for use with such prior art gripping tools and is latched, the force of the internal spring and gravity can be transferred through the linkage as axial tension forces that force the drive and driven threads to move.

The mating engagement of the latch body and the striker body resists movement of the driven threads as previously described in this disclosure. The movement of the drive threads is resisted by friction between the tensioning sides of the drive threads. However, when the resistance of the rotational unlocking motion of the drive threads resulting from friction between the tensioning flanks is low enough to allow rotation under an applied axial load (i.e., "free rotation") without externally applied torque, accidental unlocking of the linkage and consequent accidental activation of the gripping tool may occur. To avoid this potential problem, the frictional resistance to free rotation can be increased by increasing the angle of the tensioning sides. (in this context, thread flank angle refers to the angle between the thread flank and a line perpendicular to the thread axis measured in a plane containing the thread axis.)

When the linkage is unlocked and operated to translate bi-directional rotation of the load adapter relative to the clamping surface into axial movement to drive axial travel activation of the clamping assembly, a compressive axial force is generated in the linkage and is transmitted through the compression flanks of the drive threads. When the linkage transmits compressive forces, it may be desirable to reduce the frictional resistance to the rotational movement of the drive threads, which may be accomplished by reducing the angle of the compression flanks.

Thus, the asymmetric thread form may be selected such that the angle of the tension flank differs in magnitude from the angle of the compression flank.

The particular embodiments for a running tool described and illustrated in this disclosure translate bi-directional rotation into an axial extension (i.e., elongation) of a variable length axial linkage, and thus may be referred to as an "axial extension" linkage. The present disclosure also illustrates and shows varying embodiments of a variable length axial linkage configured to convert bi-directional rotation into axial retraction of the linkage (i.e., contraction of the overall length), and thus such a linkage may be referred to as an "axial retraction" linkage.

Drawings

Embodiments of the present disclosure will now be described with reference to the drawings, wherein like reference numerals designate like parts, and wherein:

fig. 1A and 1B are an elevation view and a cross-sectional view, respectively, of a prior art internal clamp down tube tool (CRTi) substantially corresponding to the CRTi shown in fig. 48 and 49 of US 8,424,939.

Fig. 2A and 2B are an elevation and cross-sectional view, respectively, of a prior art axially extending linkage installed in the CRTi of fig. 1A and 1B and substantially corresponding to the linkage shown in fig. 50A and 50B of US 8,424,939.

FIG. 3 is a schematic illustration of a portion of the operating range of the prior art axially extending linkage of FIG. 2A.

FIG. 4 is a schematic illustration of a portion of the operating range of the axially extending linkage of the present disclosure.

Fig. 5A is a cross-sectional view of a first embodiment of the axially extending linkage of the present disclosure installed in a prior art CRTi.

Fig. 5B and 5C are an elevation and cross-sectional view, respectively, of the axially extending linkage of fig. 5A in a latched position.

Fig. 5D is a partial cross-sectional view of the linkage of fig. 5B and 5C with only the idler cam body cut away.

Fig. 5E, 5F and 5G are an exploded elevation, a longitudinal cross-sectional view and an isometric view, respectively, of the linkage of fig. 5B-5D.

Fig. 6A and 6B are schematic elevational and isometric views, respectively, of an exemplary embodiment of an axially extending linkage of the present disclosure in a latched position.

Fig. 7A and 7B are schematic elevation and isometric projection views, respectively, of the linkage of fig. 6A and 6B after rotation of the drive cam body relative to the driven cam body in a first direction to unlock the linkage.

Fig. 8A and 8B are schematic elevation and isometric views, respectively, of the unlocked linkage of fig. 7A and 7B after application of an axial tensile load resulting in a partial axial extension of the drive cam body relative to the driven cam body.

Fig. 9A and 9B are schematic elevation and isometric projection views, respectively, of the unlocked linkage of fig. 8A and 8B after the drive cam body has been further axially extended relative to the driven cam body to engage the secondary driven thread stop.

Fig. 10A and 10B are schematic elevational and isometric plan views, respectively, of the unlocked and partially axially extending linkage of fig. 8A and 8B after further rotation of the drive cam body relative to the driven cam body in a first direction to a first threshold position from which further rotation in the first direction would result in further extension of the linkage.

Fig. 11A and 11B are schematic elevational and isometric views, respectively, of the unlocked and partially axially extending linkage of fig. 8A and 8B after rotation of the drive cam body relative to the driven cam body in a second direction to a second threshold position, wherein further rotation in the second direction from the threshold position results in further extension of the linkage.

Fig. 12A and 12B are a schematic elevational view and an isometric projection, respectively, of the linkage of fig. 6A and 6B in a position on the re-latch limit envelope of the linkage.

Fig. 13A and 13B are an elevational view and a cross-sectional view, respectively, of the linkage of fig. 5A and 5B in a latched position, similar to the schematic plan views of fig. 6A and 6B.

Fig. 14A and 14B are an elevational view and a cross-sectional view, respectively, of the linkage of fig. 5A and 5B rotated in a first direction to an unlocked position, similar to the schematic plan view of fig. 7A and 7B.

Fig. 15A and 15B are an elevation and cross-sectional view, respectively, of the linkage of fig. 5A and 5B in a partially extended position, similar to the schematic plan views of fig. 8A and 8B.

Fig. 16A and 16B are an elevation and cross-sectional view, respectively, of the linkage of fig. 5A and 5B in a fully extended position, similar to the schematic plan views of fig. 9A and 9B.

Fig. 17A and 17B are an elevational view and a cross-sectional view, respectively, of the linkage of fig. 5A and 5B further rotated in a first direction, similar to the schematic plan view of fig. 10A and 10B.

Fig. 18A and 18B are an elevational view and a cross-sectional view, respectively, of the linkage of fig. 5A and 5B in a second orientation, similar to the schematic plan views of fig. 11A and 11B.

Fig. 19A and 19B are an elevational view and a cross-sectional view, respectively, of the linkage of fig. 5A and 5B in a position on the re-latch limit envelope of the linkage, similar to the schematic plan views of fig. 12A and 12B.

Fig. 20 is a cross-sectional view of a second embodiment of the axially extending linkage of the present disclosure wherein the drive threads have asymmetric thread forms with different magnitudes of the tension and compression side angles.

Fig. 21A is a detail view of the drive threads of the axially extending linkage of fig. 20.

Fig. 21B is a detail view of the drive threads of the axially extending linkage of fig. 20 as they are in tension side contact.

Fig. 21C is a detail view of the drive threads of the axially extending linkage of fig. 20 as the compression sides contact.

Fig. 22A is a cross-sectional view of one embodiment of the axial retraction linkage of the present disclosure in a latched position.

FIG. 22B is a cross-sectional view of the axial retraction linkage of FIG. 22A in an unlocked state with the drive threads rotated to engage the auxiliary drive thread stop.

FIG. 22C is a cross-sectional view of the axial retraction linkage of FIG. 22A in an unlocked state and axially retracted to engage the secondary driven thread stop.

Detailed Description

Fig. 1A and 1B are an elevation view and a cross-sectional view, respectively, of a prior art internal clamp down tube tool (CRT) 100 that substantially corresponds to the CRTi shown in fig. 48 and 49 of US 8,424,939. CRT 100 includes a body assembly 110, a clamp assembly 120, and a prior art axially extending linkage 130. The upper end of the body assembly 110 is provided with a load adapter 111, as one non-limiting example, the load adapter 111 being shown with a conventional tapered threaded connection 112 for structural connection to a top drive sleeve (not shown) of a drilling rig (not shown) equipped with a top drive. The clamping assembly 120 includes a platform surface 122 carried by a bumper 121 attached to a cage 123, and a clamping surface 124 carried by the cage 123 and axially and rotationally coupled to the cage 123. The CRT 100 is shown in fig. 1B in a latched position and is inserted into a tubular workpiece 101 (shown in partial cross-section). In this latched position, relative axial movement between the body assembly 110 and the clamp assembly 120 is prevented by the axially extending linkage 130 such that the clamp assembly 120 is maintained in its retracted position.

Fig. 2A and 2B are an elevation and cross-sectional view, respectively, of a prior art axially extending linkage 130 that substantially corresponds to the linkage shown in fig. 50A and 50B of US 8,424,939. The axially extending linkage 130 includes a drive cam body 131, an intermediate cam body 132, a follower cam body 133, and a cam latch body 134. The drive threads 137 comprise external multi-start left-hand threads on the drive cam body 131 that engage internal multi-start left-hand threads on the intermediate cam body 132. The driven helical ramp 138 includes a plurality of helical right-hand ramps on the intermediate cam body 132 that engage the plurality of helical right-hand ramps on the driven cam 133 and react against the drive threads 137.

An axially extending linkage 130 acts between the body assembly 110 and the clamp assembly 120 of the CRT 100. The drive cam body 131 is carried by the body assembly 110 and is coupled to the load adapter 111 so as to be substantially stationary against rotation and axial movement relative to the load adapter 111. The follower cam body 133 is carried by the clamp assembly 120 and is coupled to the cage 123 so as to be substantially stationary against rotation and axial movement relative to the cage 123. The cam latch body 134 is carried by the follower cam body 133 and is constrained to move axially relative to the follower cam body 133 within defined limits. When CRT 100 is in the latched position, a plurality of drive cam hooks 135 on drive cam body 131 engage a corresponding plurality of cam lock hooks 136 on cam latch body 134 to limit the relative axial movement between body assembly 110 and clamp assembly 120 to thereby retain clamp assembly 120 in its retracted position. This configuration of mating shackle formed by drive cam hook 135 and cam shackle 136 is commonly referred to as a "J-latch" mechanism and is familiar to those of ordinary skill in the art.

CRT 100 is configured to move to an unlocked position in response to right-hand rotation of body assembly 110 relative to clamp assembly 120, wherein a latch actuation torque corresponds to the rotational movement and is applied to load adapter 111 by a top drive device that is reacted by a traction engagement of platform surface 122 with workpiece 101. This right-hand rotation of the body assembly 110 relative to the clamp assembly 120 causes the drive cam hook 135 and cam lock hook 136 to disengage, allowing for axial travel of the axially extending linkage 130 and corresponding relative axial movement between the body assembly 110 and the clamp assembly 120, which in turn causes the clamp surface 124 of the clamp assembly 120 to radially extend and clamp the workpiece 101.

When the axially extending linkage 130 is unlocked and axially extended such that the drive cam hook 135 cannot engage the cam lock hook 136, the drive screw threads 137 and the driven screw ramp 138 translate bi-directional rotation of the load adapter 111 relative to the clamping surface 124 in a clockwise or counter-clockwise direction, respectively, into an axial extension ("extension") of the axially extending linkage 130 to drive the axial stroke activation of the clamping assembly 120.

Fig. 3 is a schematic illustration of a portion of the operating range of a prior art axially extending linkage 130. The structural cammingline shown in fig. 3 corresponds to the drive cam pair of the axially extending linkage 130, while the disengagement cammingline corresponds to the driven cam pair (i.e., the "helical ramp"). To release the workpiece 101 and reengage the drive cam hook 135 with the cam lock hook 136, a particular sequence of operational steps must be followed, as indicated by the "re-latch" arrow in fig. 3, as described below:

a) The top drive apparatus to which CRT 100 is mounted must be rotated to the right until the rotational position of drive cam 131 exceeds the re-latch limit relative to follower cam 133;

b) The top drive must then be lowered to compress the axially extending linkage 130 until the position of the axially extending linkage 130 is on the build ramp line; and is also provided with

c) The top drive must then be simultaneously rotated and lowered to the left to reach a latched position along the build ramp line where the drive cam hook 135 engages the cam lock hook 136.

Upon completion of this operating procedure, the axially extending linkage 130 is latched, and the engaged drive cam hook 135 and cam lock hook 136 retain the clamp assembly 120 in its retracted position, thereby allowing the CRT 100 to be removed from the workpiece 101.

Fig. 4 is a schematic illustration of a portion of the operating range of a first embodiment 1300 of the axially extending linkage of the present disclosure. The build cambers shown in fig. 4 correspond to the driving thread leads of the linkage 1300, while the break away cambers correspond to the driven thread leads. In contrast to the axially extending linkage 130, which must be re-latched in a particular sequence of operations in the prior art, the axially extending linkage 1300 may be re-latched in any sequence of operations ending in a latched position. The arrow labeled "re-latch" in fig. 4 illustrates several exemplary sequences of operations.

Fig. 5A is a longitudinal cross-sectional view through an axially extending linkage 1300, the linkage 1300 being incorporated into a prior art internally clamped CRT 1000, the CRT 1000 being similar in function and operation to the CRT 100. CRT 1000 includes a body assembly 1100, a clamp assembly 1200, and an axially extending linkage 1300. The upper end of the body assembly 1100 is provided with a load adapter 1110, which load adapter 1110 is shown with a conventional tapered threaded connection 1120 for structural connection to a top drive sleeve (not shown) of a drilling rig (not shown), as one non-limiting example.

The clamp assembly 1200 includes a platform surface 1220 carried by a bumper 1210 attached to a cage 1230, and a clamp surface 1240 carried by the cage 1230 and axially and rotationally coupled to the cage 1230. CRT 1000 is shown in a latched position in fig. 5A. In this latched position, relative axial movement between the body assembly 1100 and the clamp assembly 1200 is prevented by the axially extending linkage 1300 such that the clamp assembly 1200 is maintained in its retracted position.

Fig. 5B and 5C are an elevation and cross-sectional view, respectively, of the axially extending linkage 1300 in the latched position. In this particular embodiment, the axially extending linkage 1300 is configured to be installed in the CRT 1000 as an alternative to the axially extending linkage 130 of the prior art that acts between the body assembly 1100 and the clamp assembly 1200.

Fig. 5E, 5F and 5G are an exploded elevation, cross-sectional and isometric view, respectively, of an axially extending linkage 1300. The axially extending linkage 1300 includes a drive cam body 1310, an intermediate cam body 1320, a driven cam body 1330, a primary drive thread stop 1305, a primary drive thread stop 1306, a latch body 1340, a ram body 1350, a ram retaining clip 1361, a first biasing device including a plurality of tapered spring washers 1360, a second biasing device including a coil spring 1370, an upper end ring 1371, a lower end ring 1372, a sleeve 1373, an inner retaining clip 1374, and an outer retaining clip 1375.

Fig. 5D is a partial cross-sectional view of the axially extending linkage 1300 with only the idler cam body 1330 cut away.

The drive cam body 1310 is carried by the body assembly 110 and is coupled to the load adapter 111 so as to be generally stationary, preventing rotation and axial movement relative to the load adapter 111. The idler cam body 1330 is carried by the clamp assembly 1200 and is coupled to the cage 1230 so as to be generally stationary against rotation and axial movement relative to the cage 1230. The order of operation of unlocking the axially extending linkage 1300 is the same as the order of operation of unlocking the prior art axially extending linkage 130: that is, right-hand rotation of the body assembly 1100 relative to the clamp assembly 1200 moves the axially extending linkage 1300 (and CRT 1000) to an unlocked position, as will be described in detail later in this disclosure.

The drive cam body 1310 and the intermediate cam body 1320 are threadably engaged by the drive thread 1301, the drive thread 1301 comprising an external multi-start thread 1311 on the drive cam body 1310, the external multi-start thread 1311 engaging an internal multi-start thread 1321 on the intermediate cam body 1320. The drive threads 1301 are used to translate right-hand rotation of the drive cam body 1310 relative to the intermediate cam body 1320 into axial extension of the axially extending linkage 1300. The intermediate cam body 1320 and the driven cam body 1330 are threadably engaged by the driven thread 1302, the driven thread 1302 including an external multi-start thread 1322 on the intermediate cam body 1320, the external multi-start thread 1322 engaging an internal multi-start thread 1331 on the driven cam body 1330 and acting opposite the drive thread 1301. The follower threads 1302 are used to translate left-hand rotation of the intermediate cam body 1320 relative to the follower cam body 1330 into an axial extension of the axially extending linkage 1300.

The lead angles of the drive threads 1301 and the driven threads 1302 are selected such that an axial load transmitted through the linkage 1300 causes the intermediate cam body 1320 to rotate, resulting in a change in the length of the linkage 1300.

When the drive cam body 1310 rotates leftward relative to the intermediate cam body 1320, the main drive thread stop 1305 acts between the drive cam body 1310 and the intermediate cam body 1320 to limit the range of travel of the drive thread 1301. As the intermediate cam body 1320 rotates rightward relative to the driven cam body 1330, the primary driven thread stop 1306 acts between the intermediate cam body 1320 and the driven cam body 1330 to limit the range of travel of the driven thread 1302. Both the primary drive thread stop 1305 and the primary drive thread stop 1306 are configured to be non-blocking.

The latch body 1340 is carried by the intermediate cam body 1320 and is axially slidable relative to the intermediate cam body 1320 between a first (or "latched") position and a second (or "free") position. The drive cam body 1310 has an axially downward facing cam surface 1312, which cam surface 1312 is capable of contacting and slidably engaging the axially upward facing cam surface 1341 on the latch body 1340. As best shown in fig. 5D, the plurality of pins 1342 on the latch body 1340 engage with the plurality of slots 1323 on the intermediate cam body 1320 to guide the latch body 1340 on the intermediate cam body 1320 to move between its latched and free positions.

The cam surfaces 1312 and 1341 serve to move the latch body 1340 and to stably hold the latch body 1340 in its latched position on the intermediate cam body 1320 when the drive cam body 1310 is rotated to the latched position relative to the intermediate cam body 1320. When the latch body 1340 is in its latched position, it can engage the ram body 1350.

The cam surfaces 1312 and 1341 allow the latch body 1340 to move to its free position on the intermediate cam body 1320 when the drive cam body 1310 is not in its latched position relative to the intermediate cam body 1320. The coil spring 1370 pushes the latch body 1340 against the intermediate cam body 1320 toward its free position. When the latch body 1340 is in its free position on the intermediate cam body 1320, the latch body 1340 cannot engage the ram body 1350.

When coil spring 1370 is assembled within axially extending linkage 1300, coil spring 1370 is compressed. The upper end of coil spring 1370 is connected to latch body 1340 by an upper end ring 1371, a sleeve 1373, and an inner retaining clip 1374. The lower end of coil spring 1370 is connected to intermediate cam body 1320 by a lower end ring 1372 and an outer retaining clip 1375.

The plunger body 1350 is carried by the follower cam body 1330 and is axially slidable relative to the follower cam body 1330 within a defined range. The externally splined surface 1352 on the ram body 1350 engages the internally splined surface 1333 on the driven cam body 1330, preventing relative rotation between the two bodies. The conical spring washer 1360 urges the ram body 1350 toward the "latched" position and into engagement with the latch body 1340. The ram body 1350 is axially retained and restrained within the driven cam body 1330 by the ram retaining clip 1361.

The latch body 1340 is provided with a latching surface 1343, which latching surface 1343 is for mating engagement with a latching surface 1351 on the ram body 1350. When the latch body 1340 is in its latched position, the ram body 1350 is in its latched position, and the driven thread 1302 is axially in its extreme position of the operating range, defined by abutting engagement with the primary driven thread stop 1306, the mating engagement occurs. When the latch body 1340 and the ram body 1350 are matingly engaged, the latch body 1340 and the ram body 1350 will prevent movement of the follower thread 1302 (i.e., they will prevent relative rotation between the intermediate cam body 1320 and the follower cam body 1330). The geometry of the follower thread 1302, the sliding of the ram body 1350 over the follower cam body 1330, the mating latching surfaces 1343 and 1351 on the latch body 1340 and ram body 1350, respectively, and the force of the tapered spring washer 1360 urging the ram body 1350 into engagement with the latch body 1340 may be selected such that the latch body 1340 and ram body 1350 disengage, or do not tend to disengage, under a selected combination of axial load and torque applied to the axially extending linkage 1300.

The axially extending linkage 1300 is considered to be "latched" and in its "latched position" when:

the latch body 1340 is cooperatively engaged with the striker body 1350, which requires:

o-latch body 1340 is in its latched position;

the o-ram body 1350 is in its latched position; and is also provided with

o the driven thread 1302 is axially at its extreme position of operational range, defined by abutting engagement with the driven thread stop 1306; and is also provided with

The drive cam body 1310 is in its latched position, thereby holding the latch body 1340 in its latched position.

When any of the above conditions is not met, the axially extending linkage 1300 is considered "unlocked" and in the "unlocked position".

When the axially extending linkage 1300 is unlocked and axially extended such that the latch body 1340 cannot engage the ram body 1350, the drive threads 1301 and the driven threads 1302 will translate bi-directional rotation of the load adapter 1110 in a clockwise or counter-clockwise direction (relative to the clamping surface 1240) to axial elongation (i.e., extension) of the axially extending linkage 1300, respectively, to drive axial travel activation of the clamping assembly 1200.

The axially extending linkage 1300 also includes an auxiliary driven thread stop provided by shoulder surfaces 1344 formed on the ends of a plurality of selected pins 1342 of the latch body 1340 and configured to abuttingly contact a corresponding plurality of shoulder surfaces 1332 on the driven cam body 1330, thereby limiting the operating range of the driven thread 1302 when the latch body 1340 is in its free position.

The following portions of the present disclosure illustrate typical operation of exemplary embodiments of the axially extending linkage of the present disclosure.

Fig. 6A, 6B, 7A, 7B, 8A, 8B, 9A, 9B, 10A, 10B, 11A, 11B, 12A, and 12B are schematic elevation and isometric views of an exemplary embodiment 2300 of the axially-extending linkage of the present disclosure in several operational positions similar to the operational positions of the axially-extending linkage 1300, as described below.

To facilitate a clear understanding of the structure and operation of the axially extending linkage, fig. 6A-12B illustrate a representative operative portion of the axially extending linkage 2300 of the present disclosure, but this is illustrated in a planar projection that schematically depicts a generally cylindrical linkage in two dimensions (similar to the manner in which a mercator projection illustrates the curved surface of the earth in two dimensions). While fig. 6A-12B are primarily intended to illustrate and explain three-dimensional embodiments, it should be noted that the present disclosure also contemplates practical planar embodiments for use in non-rotating applications unrelated to the primary context of the axially extending linkage described herein (i.e., running a string into a well).

In fig. 6A-12B, the movement of the axially extending linkage 2300 toward the top or bottom of these illustrations is similar to the axial movement of the axially extending linkage 1300, and the movement of the linkage 2300 toward the left or right of these illustrations (i.e., the lateral movement) is similar to the rotational movement of the axially extending linkage 1300.

The axially extending linkage 2300 includes a drive cam body 2310, an intermediate cam body 2320, a driven cam body 2330, a primary drive thread stop 2305, a primary drive thread stop 2306, a latch body 2340, a ram body 2350, a first biasing device 2360, and a second biasing device 2370. The latch body 2340 is carried by the intermediate cam body 2320 and is slidable relative to the intermediate cam body 2320 between a first (or "latched") position and a second (or "free") position. The ram body 2350 is carried by the follower cam body 2330 and is constrained to move relative to the follower cam body 2330 within a defined range. The first biasing means 2360 acts between the ram body 2350 and the follower cam body 2330 to urge the ram body 2350 toward the "latched" position and into engagement with the latch body 2340.

The drive cam body 2310 and the intermediate cam body 2320 are engaged by a drive pin-and-slot mechanism 2301, which drive pin-and-slot mechanism 2301 is one example of a threaded engagement of the two bodies. The drive pin-and-slot mechanism 2301 is used to translate leftward movement of the drive cam body 2310 relative to the intermediate cam body 2320 into axial extension of the axial extension linkage 2300. The intermediate cam body 2320 and the idler cam body 2330 are engaged by an idler pin-slot mechanism 2302, which idler pin-slot mechanism 2302 is one example of a threaded engagement of the two bodies and acts in opposition to the drive pin-slot mechanism 2301. The follower pin-and-slot mechanism 2302 is used to translate rightward movement of the intermediate cam body 2320 relative to the follower cam body 2330 into axial extension of the axial extension linkage 2300. The leftward and rightward ("lateral") movement of the drive cam body 2310 relative to the follower cam body 2330 is similar to the relative rotational movement of the axially extending linkage of the present disclosure, and these lateral movements are translated into axial extension of the linkage 2300 by the drive pin-slot mechanism 2301 and follower pin-slot mechanism 2302.

The angle of the pin-and-slot mechanisms 2301 and 2302 is an example of the angle of rise of the threaded engagement and is selected such that the axial load transmitted through the linkage 2300 causes lateral movement of the intermediate cam body 2320 and thereby changes the axial length of the linkage 2300.

As the drive cam body 2310 moves rightward relative to the intermediate cam body 2320, the primary drive thread stop 2305 acts between the drive cam body 2310 and the intermediate cam body 2320 to limit the range of travel of the drive pin-slot mechanism 2301. As the intermediate cam body 2320 moves leftward relative to the idler cam body 2330, the master-slave thread stop 2306 acts between the intermediate cam body 2320 and the idler cam body 2330 to limit the range of travel of the follower pin-slot mechanism 2302. Both the primary drive thread stop 2305 and the primary drive thread stop 2306 are configured to be non-blocking.

The drive cam body 2310 has a cam surface 2312, which cam surface 2312 is capable of contacting and slidably engaging with a cam surface 2341 on the latch body 2340. The third pin-slot mechanism 2304 guides the movement of the latch body 2340 on the intermediate cam body 2320 between its latched and free positions. When the drive cam body 2310 moves to a "latched" position relative to the intermediate cam body 2320, the cam surfaces 2312 and 2341 contact and serve to move the latch body 2340 along a path defined by the third pin-slot mechanism 2304 and then hold it stably in the latched position on the intermediate cam body 2320. When the latch body 2340 is in its latched position on the intermediate cam body 2320, it can engage with the striker body 2350.

When the drive cam body 2310 is not in its latched position relative to the intermediate cam body 2320, the cam surfaces 2312 and 2341 allow the latch body 2340 to move along a path defined by the third pin-slot mechanism 2304 on the intermediate cam body 2320 to its free position. The second biasing device 2370 urges the latch body 2340 toward its free position on the intermediate cam body 2320. When latch body 2340 is in its free position on intermediate cam body 2320, latch body 2340 cannot engage striker body 2350.

Movement of the ram body 2350 relative to the slave cam body 2330 is limited by the inclined parallel side surfaces on the ram body 2350 which slide against the inclined parallel guide surfaces on the slave cam body 2330. The helix angle associated with such sliding may be selected to be zero, such as the angle with the spline surfaces 1352 and 1333 of the axially extending linkage 1300. (helix angle is defined as the angle between the helix and a straight line parallel to the axis of the helix.)

Latch body 2340 is provided with a latch surface 2343, which latch surface 2343 is for mating engagement with a latch surface 2351 on ram body 2350. When the latch body 2340 is in its latched position, the striker body 2350 is in its latched position, and the follower pin-slot mechanism 2302 is axially in the extreme position of the operating range defined by the engagement of the master-slave thread stop 2306, a mating engagement occurs. The striker body 2350 is urged toward its latched position by a first biasing means 2360 and engages with the latch body 2340. When latch body 2340 and ram body 2350 are matingly engaged, latch body 2340 and ram body 2350 will resist movement of follower pin-and-slot mechanism 2302 (i.e., they will resist relative movement between intermediate cam body 2320 and follower cam body 2330). The geometry of follower pin-and-slot mechanism 2302, the sliding of ram body 2350 over follower cam body 2330, the geometry of mating latch surfaces 2343 and 2351 on latch body 2340 and ram body 2350, respectively, and the force of first biasing device 2370 urging ram body 2350 into engagement with latch body 2340 may be selected such that latch body 2340 and ram body 2350 disengage, or do not tend to disengage, under a selected combination of axial load and torque applied to axially extending linkage 2300.

The axially extending linkage 2300 is considered "latched" and in its "latched position" when:

latch body 2340 is cooperatively engaged with striker body 2350, which requires:

o-latch body 2340 is in its latched position;

o-ram body 2350 is in its latched position; and is also provided with

o the driven pin-slot mechanism 2302 is in its extreme position of its operating range in the axial direction, which is defined by abutting engagement with the driven-driven thread stop 2306; and is also provided with

The drive cam body 2310 is in its latched position, thereby holding the latch body 2340 in its latched position.

When any of the above conditions is not met, the axially extending linkage 2300 is considered "unlocked" and in an "unlocked position".

The axially extending linkage 2300 further includes a secondary follower thread stop, wherein the shoulder surface 2344 on the latch body 2340 and the shoulder surface 2332 on the follower cam body 2330 are configured to contact each other when the latch body 2340 is in its free position and limit the operating range of the follower pin-slot mechanism 2302.

Fig. 6A and 6B illustrate the axially extending linkage 2300 in a latched position. The drive cam body 2310 is in its "latched" position relative to the intermediate cam body 2320. The drive cam body 2310 retains the latch body 2340 in its latched position by contact of the cam surfaces 2312 and 2341. The striker body 2350 is in its latched position and the driven pin-and-slot mechanism 2302 is axially in an extreme position of the operating range defined by engagement of the driven and driven thread stops 2306. Latch body 2340 and ram body 2350 engage and inhibit relative movement between intermediate cam body 2320 and idler cam body 2330 along a path defined by idler pin-slot mechanism 2302.

The axially extending linkage 2300 is unlocked (as shown in fig. 7A and 7B) by movement of the drive cam body 2310 to the left relative to the follower cam body 2330 along a path defined by the drive pin-slot mechanism 2301, which allows the latch body 2340 to move upward to its free position under the urging of the second biasing device 2370. Latch body 2340 in its free position cannot engage striker body 2350, at which time intermediate cam body 2320 carrying striker body 2350 can move relative to idler cam body 2330 along the path defined by idler pin-slot mechanism 2302.

When the linkage 2300 is unlocked, the drive cam body 2310 can be extended axially relative to the follower cam body 2330 without lateral movement by simultaneous movement of the drive pin-slot mechanism 2301 and the follower pin-slot mechanism 2302, as can be seen by comparing fig. 8A and 8B with fig. 7A and 7B. During normal operation of the axially extending linkage mounted in CRT 1000, axial extension is limited by CRT 1000 when clamping surface 1240 of clamping assembly 1200 is in contact with a workpiece. When operation is abnormal (e.g., when the axially extending linkage is unlocked without a workpiece being present), the axial extension of the example embodiment 2300 is limited by contact of a shoulder surface 2344 on the latch body 2340 with a shoulder surface 2332 on the idler cam body 2330, as shown in fig. 9A and 9B.

With respect to fig. 8A and 8B, fig. 10A and 10B illustrate the leftward movement of the drive cam body 2310 with respect to the idler cam body 2330, with no change in axial extension. The drive cam body 2310 moves relative to the intermediate cam body 2320 along a path defined by the drive pin-slot mechanism 2301 and the intermediate cam body 2320 simultaneously moves relative to the idler cam body 2330 along a path defined by the follower pin-slot mechanism 2302. In the operative position shown in fig. 10A and 10B, the primary drive thread stop 2306 between the intermediate cam body 2320 and the idler cam body 2330 has been engaged, and any further leftward movement of the drive cam body 2310 relative to the idler cam body 2330 is translated into further axial extension and thereby increases the radial clamping force between the clamping surface 1240 and the workpiece.

Fig. 11A and 11B illustrate rightward movement of the driving cam body 2310 relative to the driven cam body 2330 with no change in axial extension relative to fig. 8A and 8B and fig. 10A and 10B. The drive cam body 2310 moves relative to the intermediate cam body 2320 along a path defined by the drive pin-slot mechanism 2301 and the intermediate cam body 2320 simultaneously moves relative to the idler cam body 2330 along a path defined by the follower pin-slot mechanism 2302. In the operating position shown in fig. 11A and 11B, the primary drive thread stop 2305 between the drive cam body 2310 and the intermediate cam body 2320 has been engaged and any further rightward movement of the drive cam body 2310 relative to the idler cam body 2330 is translated into further axial extension and increases the radial clamping force between the clamping surface 1240 and the workpiece. The drive cam body 2310 has moved the latch body 2340 to its latched position by the action of the cam surfaces 2312 and 2341 that contact and slide. However, the linkage 2300 remains unlocked because it extends axially such that the latch body 2340 cannot engage the ram body 2350.

To re-latch the linkage 2300, it must be axially retracted. Fig. 12A and 12B illustrate the linkage 2300 in a position similar to that shown in fig. 4 at the re-latch limit, specifically where the re-latch limit intersects the disengage slope line in fig. 4. The latch body 2340 contacts the ram body 2350, compressing the first biasing device 2360 because the latch body 2340 and ram body 2350 are not sufficiently laterally aligned to allow mating engagement. Further axial retraction of the linkage 2300 and the associated lateral movement (along the disengagement ramp line) will align the latch body 2340 and the striker body 2350, allowing mating engagement and returning the linkage 2300 to the latched position as shown in fig. 6A and 6B.

Fig. 13A, 13B, 14A, 14B, 15A, 15B, 16A, 16B, 17A, 17B, 18A, 18B, 19A, and 19B are an elevation view and a cross-sectional view of an axially extending linkage 1300, wherein the operational positions are shown similar to the operational positions of the axially extending linkage 2300 described above and shown in fig. 6A-12B.

Fig. 13A and 13B illustrate the axially extending linkage 1300 in a latched position. The drive cam body 1310 is in its latched position relative to the intermediate cam body 1320. The drive cam body 1310 maintains the latch body 1340 in its latched position by contact of the cam surfaces 1312 and 1341. The ram body 1350 is in its latched position with the driven thread 1302 axially in an extreme position of the operating range defined by engagement of the driven thread stop 1306. The latch body 1340 and the ram body 1350 engage and prevent relative movement between the intermediate cam body 1320 and the follower cam body 1330 along the path defined by the follower thread 1302.

The axially extending linkage 1300 is unlocked by rotation of the drive cam body 1310 to the right relative to the driven cam body 1330 along the path defined by the drive threads 1301 (as shown in fig. 14A and 14B). This rightward rotation changes the relative position of the cam surface 1312 on the drive cam body 1310 and the cam surface 1341 on the latch body 1340, which allows the latch body 1340 to move upward to its free position under the urging of the coil spring 1370. The latch body 1340 in its free position cannot engage the ram body 1350, at which time the intermediate cam body 1320 carrying the ram body 1350 can move relative to the follower cam body 1330 along the path defined by the follower thread 1302.

When the axially extending linkage 1300 is unlocked, axial extension may occur while the drive cam body 1310 does not rotate relative to the driven cam body 1330 by the drive threads 1301 and the driven threads 1302, as can be seen by comparing fig. 15A and 15B with fig. 14A and 14B. During normal operation of the axially extending linkage 1300 installed in the CRT 1000, the axial extension is limited by the CRT 1000 when the clamping surface 1240 of the clamping assembly 1200 is in contact with the workpiece. In the event of an operational anomaly (e.g., when the axially extending linkage 1300 is unlocked without a workpiece being present), the axial extension of the axially extending linkage 1300 is limited by the contact of the shoulder surface 1344 on the latch body 1340 with the shoulder surface 1332 on the follower cam body 1330, as shown in fig. 16A and 16B.

Fig. 17A and 17B illustrate the right-hand rotation of the drive cam body 1310 relative to the driven cam body 1330 with no change in axial extension relative to fig. 15A and 15B. The drive cam body 1310 moves relative to the intermediate cam body 1320 along the path defined by the drive threads 1301 and the intermediate cam body 1320 simultaneously moves relative to the driven cam body 1330 along the path defined by the driven threads 1302. In the operating position shown in fig. 17A and 17B, the primary driven thread stop 1306 between the intermediate cam body 1320 and the driven cam body 1330 has engaged and any further right-hand rotation of the drive cam body 1310 relative to the driven cam body 1330 will be translated into further axial extension and thereby increase the radial clamping force between the clamping surface 1240 and the workpiece.

Fig. 18A and 18B illustrate the left-hand rotation of the driving cam body 1310 relative to the driven cam body 1330, with no change in axial extension, relative to fig. 15A and 15B and fig. 17A and 17B. The drive cam body 1310 moves relative to the intermediate cam body 1320 along the path defined by the drive threads 1301 and the intermediate cam body 1320 simultaneously moves relative to the driven cam body 1330 along the path defined by the driven threads 1302. In the operating position shown in fig. 18A and 18B, the primary drive thread stop 1305 between the drive cam body 1310 and the intermediate cam body 1320 has been engaged and any further left-hand rotation of the drive cam body 1310 relative to the driven cam body 1330 will be translated into further axial extension and increase the radial clamping force between the clamping surface 1240 and the workpiece. The drive cam body 1310 has moved the latch body 1340 to its "latched" position by the action of the cam surfaces 1312 and 1341 that contact and slide. However, the axially extending linkage 1300 remains unlocked because it extends axially such that the latch body 1340 cannot engage the ram body 1350.

In order to re-latch the axially extending linkage 1300, it must be axially retracted. Fig. 19A and 19B illustrate the axially extending linkage 1300 in a position at the re-latch limit illustrated in fig. 4, and in particular, where the re-latch limit intersects the disengagement ramp line in fig. 4. The latch body 1340 contacts the ram body 1350, compressing the conical spring washer 1360 because the latch body 1340 and the ram body 1350 are not sufficiently rotationally aligned to allow mating engagement. Further axial retraction (and associated rotation) of the axially extending linkage 1300 will align the latch body 1340 and the striker body 1350 allowing mating engagement and return the axially extending linkage 1300 to the latched position shown in fig. 13A and 13B.

Fig. 20 is a cross-sectional view of a second embodiment 3300 of the axially extending linkage of the present disclosure. The axially extending linkage 3300 is configured for use in the prior art internal clamp CRT 1000 and includes a drive cam body 3310, an intermediate cam body 3320, a follower cam body 3330, a latch body 3340 and a ram body 3350. The drive cam body 3310 and the intermediate cam body 3320 are threadably engaged by the drive threads 3301. The intermediate cam body 3320 and the idler cam body 3330 are threadably engaged by the idler threads 3302.

Fig. 21A is a detailed view of the drive screw 3301. The drive threads 3301 include external multi-start threads 3311 on the drive cam body 3310, which external multi-start threads 3311 engage internal multi-start threads 3321 on the intermediate cam body 3320.

CRT 1000 includes an internal air spring that acts in conjunction with gravity to move clamp assembly 1200 toward engagement with a workpiece. When the axially extending linkage 3300 is latched, the force of the internal air spring and gravity may be transferred through the axially extending linkage 3300 as an axial tension force forcing the driving threads 3301 and driven threads 3302 to move. The mating engagement of the latch body 3340 and the ram body 3350 resists movement of the driven threads 3302. As shown in fig. 21B, the axial tension transmitted through the axially extending linkage 3300 also forces the tension flanks 3312 of the external multi-start threads 3311 into contact with the tension flanks 3322 of the internal multi-start threads 3321. The movement of the drive threads 3301 may be resisted by friction between the tensioning sides 3312 and 3322.

Accidental unlocking of the axially extending linkage 3300 and activation of the CRT 1000 may occur when the resistance to rotational unlocking movement of the drive threads 3301 caused by friction between the tensioning flanks 3312 and 3322 is low. To avoid this potential problem, the frictional resistance to rotation may be increased by increasing the angle of the tensioning sides 3312 and 3322.

When the axially extending linkage 3300 is unlocked and operated to translate bi-directional rotation of the load adapter 1110 relative to the clamping surface 1240 into axial movement to drive axial travel activation of the clamping assembly 1200, a compressive axial force is generated in the axially extending linkage 3300 and forces contact between the compression flanks 3313 of the outer multi-start threads 3311 and the compression flanks 3323 of the inner multi-start threads 3321, as shown in fig. 21C. When the axially extending linkage 3300 transmits a compressive force, it may be desirable to reduce the frictional resistance to rotational movement of the drive threads 3301, which may be accomplished by reducing the angle of the compression flanks 3313 and 3323.

Thus, an asymmetric thread form may be selected for the drive threads 3301 such that the angle of the tensile sides 3312 and 3322 is different in magnitude than the angle of the compressive sides 3313 and 3323.

Fig. 22A is a cross-sectional view of one embodiment 4300 of the axial retraction linkage of the present disclosure in a latched position. The axial retraction linkage 4300 includes a drive cam body 4310, an intermediate cam body 4320, a follower cam body 4330, a latch body 4340, and a ram body 4350. The drive cam body 4310 and the intermediate cam body 4320 are threadably engaged by the drive threads 4301. The intermediate cam body 4320 and the driven cam body 4330 are threadably engaged by the driven screw 4302.

The axial retraction linkage 4300 is a modification of the axial extension linkage 1300 that cannot be retrofitted into a prior art CRT 100 or prior art CRT 1000. Unlike the illustrated embodiment of the idler cam 1330, the idler cam 4330 also includes an idler cam extension 4335 having an upper end 4336. The upper end 4336 of the idler cam extension 4335 may be configured to apply external axial loads and torque in any manner known to those of ordinary skill in the art. Unlike the illustrated embodiment of the drive cam 1310, the drive cam 4310 also includes a drive cam extension 4315 having a lower end 4316. The lower end 4316 of the drive cam extension 4315 may be adapted to apply external axial loads and torque by any means known to those of ordinary skill in the art.

As shown in fig. 22B, the axial retraction linkage 4300 further includes an auxiliary drive thread stop provided by a shoulder surface 4314 formed on the end of a lug 4313, the lug 4313 being mounted to the drive cam 4310 and configured to be in abutting contact with a shoulder surface 4324 on the intermediate cam body 4320. Fig. 22B is a cross-sectional view of the axial retraction linkage 4300, the axial retraction linkage 4300 being shown in an unlocked state and the drive screw 4301 rotated such that the shoulder surface 4314 on the lobe 4313 contacts the shoulder surface 4324 on the intermediate cam body 4320, thereby limiting the operating range of the drive screw 4301.

All other portions of the axial retraction linkage 4300 are identical to the corresponding arrangement portions of the axial extension linkage 1300. Thus, the internal operation of the axial retraction linkage 4300 is the same as the internal operation of the axial extension linkage 1300, except that an auxiliary drive thread stop has been added. Due to the configuration of the drive cam extension 4315 and the idler cam extension 4335, the axial retraction linkage 4300 is latched at its longest length and retracted when unlatched. In contrast, the axially extending linkage 1300 is latched at its shortest length and extends when unlatched.

Fig. 22C is a cross-sectional view of the axial retraction linkage 4300 shown in an unlocked state with the axial retraction engaged with the auxiliary driven thread stop. This internal operating state of the axial retraction linkage 4300 shown in fig. 22C is the same as the internal operating state of the axial extension linkage 1300 shown in fig. 16A and 16B.

It will be readily appreciated by those skilled in the art that various modifications can be made to the embodiments of the disclosure without departing from the scope of the present teachings, including modifications using equivalent structures or materials hereafter devised or developed.

It should be particularly understood that the scope of the present disclosure is not limited to the embodiments illustrated or described, and that any substitution of any claim or claim-illustrated variation in elements or features does not constitute a departure from the scope of the present disclosure without any substantial change in function as a result.

In this patent document, the term "comprising" is to be taken in a non-limiting sense, i.e. including any elements or features that follow the term, but not excluding any elements or features not specifically mentioned. The use of the indefinite article "a" or "an" 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.

Any use of any form of the terms "connected," "joined," "coupled," "attached," or any other term describing an interaction between elements as used herein is not meant to limit the interaction to a direct interaction between the elements, but may also include an indirect interaction between elements, such as an interaction achieved through auxiliary or intermediate structures.

Relational and conformational terms such as, but not limited to, "parallel," "axial," and "coaxial" are not intended to mean or require absolute mathematical or geometric precision. Accordingly, these terms should be understood to mean or require only substantially precise (e.g., "substantially parallel") unless the context clearly requires otherwise.

The term "exemplary" and grammatical variations thereof as used anywhere herein should be understood and interpreted as representing general usage or practice and is not intended to be understood or interpreted as implying importance or invariance.

List of reference numerals

Element mark description 100CRT (lower tube tool)

101. Tubular workpiece

110. Main body assembly

111. Load adapter

112. Threaded connection

120. Clamping assembly

121. Buffer device

122. Platform surface

123. Cage 130 (prior art) axially extending linkage 131 drives the cam body

132. Intermediate cam body

133. Driven cam body

134. Cam latch body

135. Driving cam hook

136. Cam lock hook

137. Drive screw

138. Driven spiral bevel 1000CRT (lower tube tool)

1100. Main body assembly

1110. Load adapter

1120. Threaded connection

1200. Clamping assembly

1210. Buffer device

1220. Platform surface

1230. Cage

1300. Axially extending linkage

1301. Drive screw

1302. Driven screw thread

1305. Main drive thread stop

1306. Master and slave thread stop

1310. Driving cam body

1311 external multi-start screw-drive cam body

1312 cam surface-drive cam body

1320 intermediate cam body

1321 internal multi-start thread-intermediate cam body

1322 external multi-start thread-intermediate cam body

1323 slot-intermediate cam body

1330 driven cam body

1331 multi-start screw-driven cam body

1332 shoulder surface-driven cam body

1333 internal spline surface-driven cam body

1340 latch body

1341 cam surface-latch body

1342 pin-latch body

1343 latch surface-latch body

1344 shoulder surface-latch body

1350 bump body

1351 latch surface-striker body

1352 external spline surface-ram body

1360. Conical spring washer

1361. Bump block fixing clamp

1370. Spiral spring

1371. Upper end ring

1372. Lower end ring

1373. Casing pipe

1374. Inner retaining clip

1375. Outer retaining clip

2300. Exemplary embodiments of the invention

2301 drive pin-slot mechanism

2302 follower pin-slot mechanism

2304 third pin-slot mechanism

2305. Main drive thread stop

2306. Master and slave thread stop

2310. Driving cam body

2312 cam surface-drive cam body

2320. Intermediate cam body

2330. Driven cam body

2332 shoulder surface-driven cam body

2340 latch body

2341 cam surface-latch body

2343 latch surface-latch body

2344 shoulder surface-latch body

2350 ram body

2351 latch surface-ram body

2360. First biasing means

2370. Second biasing means

3300. Axially extending linkage

3301. Drive screw

3302. Driven screw thread

3310. Driving cam body

3311 external multiple start screw-drive cam body

3312 tensioning of the drive threads on the side-drive cam body

3313 compression side-drive cam body drive threads

3320 middle cam body

3321 internal multi-start thread-intermediate cam body

3322 tensioning drive threads on side-to-middle cam body

3323 compression side-drive threads on an intermediate cam body

3330. Driven cam body

3340. Latch body

3350. Ram main body

4300. Axial retraction linkage

4301. Drive screw

4302. Driven screw thread

4310. Driving cam body

4313. Lug boss

4314 shoulder surface-lugs

4315 drive cam body extension

4316 drive cam body extension lower end

4320 middle cam body

4324 shoulder surface-intermediate cam body

4330. Driven cam body

4335. Slave cam body extension

4336 upper end of the cam follower body extension

4340. Latch body

4350. A ram body.

Claims (11)

1. A variable length axial linkage comprising:

(a) A driving cam body;

(b) An intermediate cam body;

(c) A driven cam body; and

(d) A latch mechanism;

wherein:

(e) The drive cam body and the intermediate cam body are threadably engaged by a drive thread having a primary drive thread stop;

(f) The intermediate cam body and the driven cam body are threadably engaged by a driven thread having a driven thread stop;

(g) The selected one of the driving thread and the driven thread is a left-hand thread;

(h) The unselected one of the driving thread and the driven thread is a right-handed thread;

(i) The lead angle and thread form of the drive and driven threads are selected such that axial loads transmitted through the linkage force rotation of the intermediate cam body;

(j) The primary drive thread stop is configured to be non-blocking and limit an amount of rotation of the drive thread in a selected rotational direction; and is also provided with

(k) The primary and secondary driven thread stops are configured to be non-blocking and limit the amount of rotation of the secondary driven thread in a non-selected rotational direction.

2. The linkage of claim 1 wherein the latch mechanism comprises a J-latch mechanism.

3. The linkage of claim 1, wherein the latch mechanism comprises:

(a) A latch body carried by and slidable relative to the intermediate cam body between a latch body latching position and a free position on the intermediate cam body;

(b) A ram body carried by the driven cam body and slidable within defined limits relative to the driven cam body; and

(c) A first biasing means acting between the striker body and the follower cam body to urge the striker body toward the striker body latching position and into engagement with the latch body;

wherein:

(d) The drive cam body has a drive cam body cam surface that is slidably in contact engagement with a latch body cam surface on the latch body to:

movement of the drive cam body relative to the intermediate cam body to the drive cam body latching position causes relative movement between the drive cam body cam surface and the latch body cam surface, thereby moving the latch body to the latch body latching position on the intermediate cam body and stably holding the latch body in the latch body latching position;

when the drive cam body is not in the drive cam body latching position, relative movement between the drive cam body cam surface and the latch body cam surface will allow the latch body to move to a free position on the intermediate cam body;

the latch body engaging with the striker body when the latch body is in the latch body latching position on the intermediate cam body; and is also provided with

When the latch body is in the free position on the intermediate cam body, the latch body is not engaged with the striker body; and is also provided with

(e) The latch body has a latch surface configured to matingly engage the latch surface on the striker body, wherein:

said mating engagement of said latch surfaces of the latch body and the striker body occurs when the latch body is in the latch body latching position, the striker body is in the striker body latching position, and the linkage is in its extreme position of the operating range in the axial direction, and the primary drive thread stop and the primary driven thread stop are engaged; and is also provided with

When the latch body and the striker body are cooperatively engaged, the latch body and the striker body limit relative rotation between the intermediate cam body and the follower cam body.

4. A linkage as claimed in claim 3 wherein the angle of the tension flank of the drive thread is selected to prevent free rotation under axial load reacted by the tension flank of the drive thread.

5. A linkage as claimed in claim 3, further comprising a second biasing means which urges the latch body towards the free position on the intermediate cam body.

6. The linkage of claim 5 further comprising an auxiliary driven thread stop, wherein the shoulder surface on the latch body and the shoulder surface on the driven cam body are configured to form a contact engagement to limit the range of operation of the driven thread in a selected rotational direction when the latch body is in a free position on the intermediate cam body.

7. The linkage of any one of claims 1-4, further comprising a secondary driven thread stop.

8. The linkage of any one of claims 1-7, further comprising an auxiliary drive thread stop.

9. The linkage of any one of claims 1-8, wherein at least one of the driving thread and the driven thread is a multi-start helical thread.

10. The linkage of any one of claims 1-9, wherein the linkage is an axially extending linkage.

11. The linkage of any one of claims 1-9, wherein the linkage is an axial retraction linkage.