阅读说明：本技术 用于改善夹头型机构内接触应力分布的装置和方法 (Apparatus and method for improving contact stress distribution in a collet-type mechanism ) 是由 M.W.斯莱克 V.扬 于 2020-03-06 设计创作，主要内容包括：一种用于可释放地夹持管状工件的外部或内部目标表面的夹头型机构,包括限定夹头接收器接触表面的夹头接收器,该夹头接收器接触表面构造为截头直圆锥的弯曲侧表面,以及包括多个夹头段的分段夹头组件。每个夹头段限定了工件接合表面和夹头段接触表面,工件接合表面构造为用于与工件目标表面夹持接合,夹头段接触表面构造为用于与夹头接收器接触表面至少部分接触接合。夹头段接触表面可以包括两个轴向邻接的区域,其中一个对应于倾斜圆柱或直圆柱的弯曲侧表面,而另一个对应于截头直圆锥的弯曲侧表面。(A collet-type mechanism for releasably gripping an external or internal target surface of a tubular workpiece includes a collet receiver defining a collet receiver contact surface configured as a curved side surface of a truncated right circular cone, and a segmented collet assembly including a plurality of collet segments. Each collet segment defines a workpiece engagement surface configured for gripping engagement with a workpiece target surface and a collet segment contact surface configured for at least partial contacting engagement with a collet receiver contact surface. The collet segment contact surface may comprise two axially abutting regions, one of which corresponds to the curved side surface of an inclined or straight cylinder and the other of which corresponds to the curved side surface of a truncated right circular cone.)

1. A collet-type mechanism comprising:

(a) a collet receiver defining a collet receiver contact surface configured as a curved side surface of a truncated right circular cone; and

(b) a segmented collet assembly comprising a plurality of collet segments, each collet segment defining:

a workpiece engagement surface configured to engage a workpiece to be gripped by the collet-type mechanism; and

a collet segment contact surface configured for at least partial contacting engagement with a collet receptacle contact surface, wherein the curvature of the collet segment contact surface is constant along at least a portion of the axial length of the collet segment when viewed in a cross-section transversely perpendicular to the longitudinal axis of the collet mechanism.

2. The collet-type mechanism of claim 1, wherein each collet segment contact surface is at least partially configured as a portion of a curved side surface of a cylinder.

3. The collet-type mechanism of claim 2, wherein each collet segment contact surface is configured as a portion of a curved side surface of an angled cylinder.

4. A collet-type mechanism as defined in claim 2, wherein each collet segment contact surface is configured as a portion of a curved side surface of a right circular cylinder.

5. The collet-type mechanism of claim 2, wherein each collet segment contact surface comprises a first surface area and a second surface area, wherein the first and second surface areas are axially contiguous, and wherein:

(a) the first surface area is at least partially configured as a portion of a curved side surface of the cylinder; and

(b) the second surface area is at least partially configured as a portion of the curved side surface of a truncated right circular cone.

6. A collet-type mechanism as defined in claim 5, wherein the cylinder is an inclined cylinder.

7. A clip-type mechanism as claimed in claim 5, wherein the cylinder is a right circular cylinder.

8. The collet-type mechanism of any one of claims 1-7, wherein the collet-type mechanism is configured to clamp an inner cylindrical surface of a workpiece.

9. The collet-type mechanism of any one of claims 1-7, wherein the collet-type mechanism is configured to clamp an outer cylindrical surface of a workpiece.

10. An internally gripped tubular running tool comprising:

(a) an elongated mandrel defining an outer mandrel surface configured to define a plurality of mandrel contact surfaces corresponding to the curved surface of the frustum; and

(b) a plurality of slip elements, each slip element having:

an outer workpiece engaging surface configured for clamping engagement with an inner surface of a tubular workpiece; and

a plurality of inner surface regions, each inner surface region configured for contacting engagement with a corresponding one of the mandrel contact surfaces, at least a portion of each inner surface region configured to correspond to a curved surface of a cylinder, wherein the cylinder is selected from the group consisting of a tilted cylinder and a right cylinder.

11. An externally gripped tubular running tool comprising:

(a) an elongated, generally cylindrical mandrel having an inner bore defining a plurality of mandrel contact surfaces configured to correspond to the curved surfaces of the frustum; and

(b) a plurality of slip assemblies, each slip assembly including a mold and a gripping jaw, wherein:

each die defining an inner workpiece engaging surface configured for clamping engagement with the outer surface of the tubular workpiece; and

each jaw defines an outer contact surface area configured for contacting engagement with a corresponding one of the spindle contact surfaces, at least a portion of each outer surface area being configured to correspond to a curved surface of a cylinder, wherein the cylinder is selected from the group consisting of an inclined cylinder and a right circular cylinder.

Technical Field

The present disclosure relates generally to collet-type and slip-type devices and mechanisms for releasably gripping an object or workpiece such that when an axial load is transmitted in one direction between the collet and its receiving sleeve, displacement of the workpiece relative to the collet is strongly resisted and when the direction of the axial load is opposite, the collet is urged to release the workpiece.

Background

For over a hundred years, collet-type mechanisms have been widely used in a variety of devices and mechanisms. Examples of clip-type mechanisms can be found in many devices, including but not limited to:

a chuck on the milling machine for holding the tool;

a chuck on a multi-bit screwdriver for holding bits;

a chuck on the telescoping leg assembly for locking the position of the concentric leg segments relative to each other;

slips on the rig for holding the string; and

tubular running tools such as those described in us patent No. 7,909,120(Slack) and us patent No. 10,081,989 (Slack).

The collet-type mechanism has many advantages, including the following:

self-centering of the workpiece relative to the chuck mechanism;

precise centering of the workpiece relative to the chuck mechanism;

strong clamping of the workpiece;

prevent the workpiece from being jarred loose (i.e., not tightened); and

the ability to quickly release and replace a clamped workpiece.

The collet-type mechanism that holds the outer surface of the workpiece is commonly referred to as an outer collet. A collet-type mechanism that grips the inner surface of the workpiece is commonly referred to as an inner collet.

Conventional collet-type mechanisms typically include two contact members: a segmented collet assembly (or simply "segmented collet" herein) and a collet receiver. The surface of the collet receiver contacting the segmented collet is configured as a curved side surface of a truncated right circular cone. The surface of the segmented collet (i.e., the surface of the collet segments) that contacts the collet receiver is also configured as a curved side surface of a truncated right circular cone. The segments of the segmented collet act as wedges (wedges) between the collet receivers and the workpiece.

Applying an axial load to the segmented collet in one direction relative to the collet receiver will increase the clamping force on the workpiece. Applying an axial load to the segmented collet in the opposite direction will cause the collet mechanism to release the workpiece. Axial loads may be applied to the segmented collet by a workpiece, such as a conventional drill slip (in which case the workpiece is a length of pipe). Alternatively, the axial load may be applied to the segmented collet primarily in a workpiece-independent manner, as is the case with conventional chucks on milling machines.

As used in this disclosure, the term "collet segment" is understood to refer to a segment of a segmented collet. The collet segments in a given segmented collet may be physically separated from one another or may be coupled by some means that allows a selected degree of relative movement between the collet segments in one or more directions or fingers. Non-limiting examples of means for allowing relative movement between coupled collet segments include providing an integral metal spring, and forming the collet using two or more materials having different bending stiffnesses.

When the collet-type mechanism is used to clamp a workpiece having a dimension corresponding to the "nominal" dimension of the collet-type mechanism (typically corresponding to a "nominal" inner or outer diameter), when the segmented collet is at a "nominal" axial reference position along the length of the collet receiver, the collet segments will contact the collet receiver and begin to clamp the workpiece. In this nominal reference position, the contact surfaces of the collet segments and collet receivers have the same radius at each axial position along the length of the component, so the contact surfaces will coincide. When an axial force is applied to the segmented collet to increase the clamping force, the resulting contact stress distribution between the collet segments and the collet receiver will be nearly uniform. For purposes of this disclosure, this type of contact state will be referred to as a "mating contact" (as discussed further later with reference to fig. 1A and 2A).

When the collet-type mechanism holds a workpiece of a non-nominal size, the collet segments will contact the collet receiver and begin to clamp the workpiece when the segmented collet is located at an axial position within the collet receiver that is away from the nominal axial reference position. The radius of curvature of the contact surfaces of the collet segments and collet receivers will be different at each axial position. When an axial force is applied to the segmented collet to increase the clamping force, the contact stress distribution created between the collet segments and the collet receiver will not be as uniform as if the workpiece had a nominal size.

With an internal collet mechanism, if the size of the workpiece is smaller than the nominal size of the collet, the contact surface area of each collet segment with the collet receiver will decrease toward the longitudinal center of each collet segment. For purposes of this disclosure, this type of contact condition will be referred to as "center contact" (as discussed further later with reference to fig. 2B).

If the size of the workpiece is greater than the nominal size of the collet, the contact surface area of each collet segment with the collet receiver will decrease toward both longitudinal edges of each collet segment. For purposes of this disclosure, this type of contact state will be referred to as "edge contact" (as discussed further later with reference to fig. 1C and 2C).

For an external collet mechanism, edge contact occurs if the size of the workpiece is smaller than the nominal size of the collet (as shown in fig. 1C). If the size of the workpiece is larger than the nominal size of the chuck, center contact occurs (as shown in FIG. 1B).

As noted above, when the nominal dimensions of the workpiece and the collet are different, the reduction in contact surface area results in an increase in the maximum contact stress for a given clamping force. This increase in maximum contact stress is more pronounced with a given axial position change from mating contact to edge contact than with the same magnitude of axial position change to center contact. Slippage between the contacting surfaces can occur when the clamping force is increased, or when the workpiece is released, or if the collet mechanism allows relative rotation (such as in the tubular running tool described in US7,909,120). As the maximum contact stress increases, the risk of the contact surfaces wearing or otherwise failing increases. To this end, an acceptable size range for the workpiece designated for certain collet mechanisms may be selected to produce a mating or center contact and avoid edge contact.

If torque is transferred between the collet receiver and the workpiece through the collet mechanism, each collet segment will have a greater tendency to rotate along an axis that is generally parallel to the longitudinal axis of the collet mechanism when in the center contact condition than when the collet segments are in the mating or edge contact condition. Such rotation of the jaw segments may cause the jaw mechanism to jam and impair the ability of the jaw mechanism to quickly release the workpiece. Thus, the collet segments are described as having less stability when in a center-contact state than when in a mating-contact state or an edge-contact state.

Disclosure of Invention

In general, the present disclosure teaches embodiments of collet-type mechanisms in which the state of contact between the collet segments and the collet receivers is less dependent on the size of the workpiece being gripped by the mechanism than prior art collet-type mechanisms having tapered contact surfaces on both the collet segments and the collet receivers. The present disclosure also teaches embodiments of a method for selecting a surface configuration of a collet segment that contacts a collet receiver.

More specifically, the present disclosure teaches a collet-type mechanism in which the surface of the collet receiver that contacts the collet segments is configured as a curved side surface of a truncated right circular cone, and the surface of each collet segment that contacts the collet receiver (which surface is also referred to herein as the "collet segment contact surface") is configured with a curvature that is constant along at least a portion of the axial length of the collet segments when viewed in a cross-section that is transverse to the longitudinal axis of the mechanism. In the most general form, each collet segment contact surface is configured as an arc having a curvature similar to the curvature of the tapered collet receiving surface and projects along a line parallel to the taper of the tapered collet receiving surface over at least a portion of its length.

Embodiments within the scope of the present disclosure include collet segments in which the surface contacting the collet receiver is configured at least in part as a curved side surface of a cylinder, wherein the cylinder may be an angled cylinder in some embodiments, and a right cylinder in other embodiments. As used in this disclosure:

the term "inclined cylinder" (or "OCC") is understood to mean a cylinder having two planar circular bases of equal diameter, parallel to each other, and with an "OCC" axis extending between the centres of the bases, wherein the OCC axis is not perpendicular to the bases;

the term "right circular cylinder" (or "RCC") is understood to mean a cylinder having two planar circular bases of equal diameter, the two bases being parallel to each other, and the "RCC" axis extending between the centres of the bases, with the RCC axis being perpendicular to the bases; and

the term "cylindrical surface" is understood to mean the curved lateral surface of an inclined or right-angled cylinder, excluding the surface of the base of the cylinder.

The angle of inclination of the cylinder is understood to mean the angle between the OCC or RCC axis (as the case may be) and the normal vector extending from the centre of the base. For Right Circular Cylinders (RCC), the angle of inclination is zero. For an oblique cylinder (OCC), the angle of inclination is not zero.

The term "collet receiver contact surface" should be understood to mean a surface of the collet receiver that contacts the collet segments.

For both the outer and inner collet mechanisms, the angle between the axis of the cylindrical surface of each collet segment and the axis of the tapered collet receiver contact surface may be selected to be equal to the taper angle of the tapered collet receiver contact surface.

The radius of the cylindrical surface of the collet segments may be selected based on the design goals of the collet mechanism to optimize the contact stress distribution. For an external collet mechanism, the radius of the cylindrical surface on each collet segment may be selected to mate with the minimum radius of the tapered collet receiver contact surface. For an internal collet mechanism, the radius of the cylindrical surface on each collet segment may be selected to mate with the largest radius of the tapered collet receiver contact surface.

The angle of inclination of the cylinder defining a portion of the contact surface of each collet segment may also be selected based on the particular design goals of the collet-type mechanism to optimize the contact stress distribution. In one embodiment according to the present disclosure, the angle of inclination is selected to be equal to the angle of taper of the tapered collet receiver contact surface, and the resulting portion of the contact surface on each collet segment is a portion of the inclined cylindrical surface. In another embodiment, the angle of inclination is selected to be less than the angle of taper of the tapered collet receiver contact surface, e.g., the angle of inclination is equal to zero, and the resulting portion of the contact surface of each collet segment is a portion of a straight cylindrical surface. In another embodiment, the angle of inclination is selected to be greater than the angle of taper of the tapered collet receiver contact surface.

By way of further explanation, the contact stress distribution can be optimized by selecting the inclination angle and radius of the cylindrical surface on the collet segments in contact with the collet receiver according to the following principles:

for the inner cartridge:

decreasing the angle of inclination or radius will cause the contact condition between the collet segments and the collet receivers to deviate in the direction away from the center contact and toward the edge contact; and

increasing the angle or radius of inclination will cause the contact condition between the collet segments and the collet receiver to deviate in the direction away from the edge contact and toward the center contact.

For external chucks:

decreasing the angle of inclination or radius will cause the contact condition between the collet segments and the collet receivers to deviate in directions away from the edge contact and toward the center contact; and

increasing the angle or radius of inclination will cause the contact condition between the collet segments and the collet receivers to deviate in the direction away from the center contact and toward the edge contact.

It will be apparent to those skilled in the art that when the angle of inclination of the cylindrical surface of each collet segment is selected to be equal to the angle of taper of the tapered contact surface of the collet receiver, mating contact will occur at an axial position where the radius of the collet receiver is equal to the radius selected for the contact cylindrical surface of the collet segment (e.g., at the smallest radius of the taper for the outer collet mechanism and at the largest radius of the taper for the inner collet mechanism), regardless of the size of the workpiece.

For purposes of further explanation, using the inner collet as an example, when the angle of inclination is selected to be less than the angle of taper, contact between the collet segments and the collet receiver will tend toward the direction of edge contact. However, unlike the edge contact found in prior art inner chucks having tapered contact surfaces on the chuck segments and chuck receivers, the degree of bias toward edge contact is independent of the workpiece size and is controlled by selecting the angle of inclination and radius of the cylindrical surface of the chuck segment that contacts the chuck receiver.

When the angle of inclination is selected to be greater than the angle of taper, the contact between the collet segments and the collet receiver will tend to be center contact. However, unlike the center contact found in prior art chucks having tapered contact surfaces on both the segmented chuck and the chuck receiver, the degree of bias toward the center contact is independent of the workpiece size and is controlled by selecting the angle of inclination and radius of the cylindrical surface of the chuck segment that contacts the chuck receiver.

Thus, a collet-type mechanism according to the present invention may be designed such that the contact stress distribution between the segmented collet and the collet receiver is less dependent on variations in workpiece dimensions than other similar prior art collet mechanisms having tapered contact surfaces on the collet segments and on the collet receiver. Because the cylindrical surface of the collet segments has a constant radius along their length, while the tapered collet receiver contact surface has a varying radius along its length, the contact condition varies along the axial length of the collet, while also being independent of the workpiece size. Thus, the collet segments can be designed for greater stability when transferring torque between the collet mechanism and a workpiece of a workpiece size that would otherwise result in a state of contact with the center of the prior art collet mechanism.

This increased stability is due to the provision of a larger contact width in the lateral direction. The same collet segments may also provide lower contact stresses for workpiece sizes that would otherwise result in contact with the edges of prior art collets. This lower contact stress is due to the reduction and/or elimination of edge contact and the provision of a larger contact surface area. The center contact also increases correspondingly, which provides a gradually converging contact surface that may enhance lubrication of the collet-type mechanism that allows relative rotation (e.g., in a tubular running tool of the type described in US7,909,120).

In summary, therefore, the present disclosure teaches a collet-type mechanism that includes a collet receiver defining a collet receiver contact surface configured as a curved side surface of a truncated right circular cone, and a segmented collet assembly including a plurality of collet segments. Each collet segment defines:

a workpiece engagement surface configured to engage a workpiece to be gripped by the collet-type mechanism; and

a collet segment contact surface configured for contacting engagement with at least part of a collet receptacle contact surface, wherein the curvature of the collet segment contact surface is constant along at least part of the axial length of the collet segment when viewed in a cross-section transversely perpendicular to the longitudinal axis of the collet mechanism.

In some embodiments, each collet segment contact surface is at least partially configured as part of a curved side surface of a cylinder, which may be an inclined cylinder or a straight cylinder.

In other embodiments, each collet segment contact surface comprises axially adjoining first and second surface regions, wherein the first surface region is configured at least partially as a portion of a curved side surface of an inclined cylinder or a right cylinder; and the second surface area is at least partially configured as part of the curved side surface of a truncated right circular cone.

A collet-type mechanism according to the present disclosure may be configured as an "internal" collet mechanism for gripping an internal cylindrical surface of a workpiece, or as an "external" collet mechanism for gripping an external cylindrical surface of a workpiece. Thus, a collet-type mechanism according to the present disclosure may be incorporated into an internally gripped tubular running tool, such as:

an internally gripping tubular running tool comprising:

an elongated mandrel defining an outer mandrel surface configured to define a plurality of mandrel contact surfaces corresponding to the curved surface of the frustum (such that the mandrel effectively acts as a collet receiver in accordance with the present teachings); and

a plurality of slip elements, each slip element having:

an outer workpiece engaging surface configured for clamping engagement with an inner surface of a tubular workpiece; and

a plurality of inner surface areas, each inner surface area configured for contacting engagement with a corresponding one of the mandrel contact surfaces, at least a portion of each inner surface area configured to correspond to a curved surface of a cylinder, which may be an inclined cylinder or a straight cylinder (such that the slips effectively function as a collet segment in accordance with the present teachings).

And:

an externally gripping tubular running tool comprising:

an elongated, generally cylindrical mandrel having an inner bore defining a plurality of mandrel contact surfaces configured to correspond to the curved surfaces of the frustum cone (such that the mandrel effectively acts as a collet receiver in accordance with the present teachings); and

o a plurality of slip assemblies, each slip assembly comprising a mold and a gripping jaw, wherein:

each die defining an inner workpiece engaging surface configured for clamping engagement with the outer surface of the tubular workpiece; and

each jaw defines an outer contact surface area configured for contacting engagement with a corresponding one of the mandrel contact surfaces, at least a portion of each outer surface area being configured to correspond to a curved surface that is cylindrical, which may be an inclined cylinder or a right cylinder (such that the slip effectively functions as a jaw segment in accordance with the present invention).

Drawings

Embodiments in accordance with the present disclosure will now be described with reference to the accompanying drawings, wherein like reference numerals represent like parts, and in which:

FIG. 1A is a detailed view through a cross section of an outer collet including a collet receiver and a segmented collet, showing a "mating contact" condition between the collet receiver and one segment of the segmented collet.

FIG. 1B is a detailed view through a cross section of an outer collet similar to FIG. 1A, but showing a "center contact" condition between the collet receiver and the collet segments.

FIG. 1C is a detailed view through a cross section of an outer collet similar to FIG. 1A, but showing an "edge contact" condition between the collet receiver and the collet segments.

Figure 2A is a detailed view through a cross section of an inner collet including a collet receiver and a segmented collet showing a "mating contact" condition between the collet receiver and one segment of the segmented collet.

Fig. 2B is a detailed view through a cross section of the inner collet similar to fig. 2A, but showing a "center contact" condition between the collet receiver and the collet segments.

Fig. 2C is a detailed view through a cross section of the inner collet similar to fig. 2A, but showing an "edge contact" condition between the collet receiver and the collet segments.

Fig. 3A is a longitudinal cross-sectional view of a first embodiment of an outer collet according to the present disclosure, showing the outer collet engaging a workpiece having a maximum outer diameter that the outer collet is designed to grip.

Figure 3B is an isometric view of the chuck and workpiece of figure 3A.

Fig. 4A is a longitudinal cross-sectional view through the outer collet of fig. 3A, showing the collet engaged with a workpiece having the smallest outer diameter that the outer collet is designed to grip.

Figure 4B is an isometric view of the outer cartridge and workpiece of figure 4A.

Fig. 5A is an isometric view of a collet segment of the outer collet shown in fig. 3A.

Fig. 5B is a longitudinal elevational view of the clip segment shown in fig. 5A.

Figure 6A is a longitudinal cross-sectional view of a first embodiment of an inner collet according to the present disclosure, showing the inner collet engaging a workpiece having a minimum inner diameter that the inner collet is designed to grip.

Figure 6B is an isometric view of the inner cartridge and workpiece of figure 6A.

Fig. 7A is a longitudinal cross-sectional view through the inner collet of fig. 6A showing the collet engaged with a workpiece having the largest inner diameter that the inner collet is designed to grip.

Figure 7B is an isometric view of the inner cartridge and workpiece of figure 7A.

Figure 8A is an isometric view of the collet segments of the inner collet shown in figure 6A.

Fig. 8B is a longitudinal cross-sectional view of the collet segment of fig. 8A.

Figures 9A and 9B are isometric partial and longitudinal sections, respectively, through an internally gripping tubular running tool, generally as shown in figures 8 and 9 of international publication No. WO 2010/006441 (the contents of which are hereby fully incorporated herein within the jurisdiction as so permitted), modified to incorporate features in accordance with the present disclosure, showing the gripping assembly of the tubular running tool positioned within the bore of the tubular workpiece prior to initiating internal gripping engagement therewith.

FIG. 10 is an isometric free body view of one of the integral slips of the tubular running tool shown in FIGS. 9A and 9B, incorporating features according to the present invention.

11A and 11B are perspective and longitudinal cross-sectional views, respectively, of an internally gripping tubular running tool, generally as disclosed in US7,909,120 and US 10,081,989 (the contents of both of which are hereby fully incorporated herein within the jurisdiction as so permitted), modified to incorporate features in accordance with the present disclosure, the gripping assembly of the tubular running tool being disposed about the upper outer surface of the tubular workpiece prior to initiating external gripping engagement therewith.

FIG. 12 is an isometric free body view of one integrated slip of the tubular running tool of FIGS. 11A and 11B, incorporating features according to the present disclosure.

Detailed Description

Collet contact geometry and contact stress-overview

The contact geometry and contact stress between the collet segments and the collet receiver can be theoretically predicted using contact mechanics analytical equations found in the published text, for example:

·Budynas,Richard G.and Nisbett,J.Keith,Shigley's Mechanical Engineering Design,10^thed. (New York: McGraw-Hill Edurition, 2014); and

·Boresi,Arthur P.and Sidebottom,Omar M.,Advanced Mechanics of Materials,4^th ed.(New York：John Wiley&Sons,1985)。

finite element analysis software tools may also be used to predict contact geometry and contact stress and may provide more accurate predictions than the analytical equations of some collet-type mechanisms.

Fig. 1A is a cross-section through an external collet mechanism 100 that includes a collet receiver 110 having an inner surface 111, and a segmented collet including a plurality of collet segments 120, each collet segment having an outer surface 121. Fig. 1A shows a mating contact condition between the collet receiver 110 and one of the collet segments 120. In the mating contact state of the outer collet as shown in fig. 1A, the outer surface 121 of the collet segments 120 has the same radius of curvature as the inner surface 111 of the collet receiver 110.

FIG. 1B is similar to FIG. 1A, but shows a center contact condition between the collet receiver 110 and the collet segments 120. In the center contact state of the outer collet as shown in fig. 1B, the outer surface 121 of the collet segments 120 has a smaller radius of curvature than the inner surface 111 of the collet receiver 110.

FIG. 1C is similar to FIG. 1A, but shows an edge contact condition between the collet receiver 110 and the collet segments 120. In the edge-contacting condition of the outer collet as shown in fig. 1C, the outer surface 121 of the collet segments 120 has a larger radius of curvature than the inner surface 111 of the collet receiver 110.

Fig. 2A is a cross-section through an inner collet mechanism 200, the inner collet mechanism 200 including a collet receiver 210 having an inner surface 211, and a segmented collet including a plurality of collet segments 220, each collet segment having an outer surface 221. Fig. 1A shows a mating contact condition between the collet receiver 210 and one of the collet segments 220. In the mated contact state of the inner collet as shown in fig. 2A, the inner surface 221 of the collet segments 220 has the same radius of curvature as the outer surface 211 of the collet receiver 210.

FIG. 2B is similar to FIG. 2A, but shows a center contact condition between the collet receiver 210 and the collet segments 220. In the center contact state of the inner collet as shown in fig. 2B, the inner surface 221 of the collet segment 220 has a larger radius of curvature than the outer surface 211 of the collet receiver 210.

Fig. 2C is similar to fig. 2A, but shows an edge contact condition between the collet receiver 210 and the collet segments 220. In the edge contact state of the inner collet as shown in fig. 2C, the inner surface 221 of the collet segments 220 has a smaller radius of curvature than the outer surface 211 of the collet receiver 210.

Example #1 external chuck mechanism

Fig. 3A and 4A are longitudinal cross-sectional views through an embodiment 1000 of an external collet mechanism according to the present disclosure. The outer collet 1000 has a longitudinal axis 1050 and includes a collet receiver 1100 and a segmented collet including a plurality of collet segments 1200. The collet receiver 1100 has a bore defining a collet receiver contact surface 1110, the collet receiver contact surface 1110 being configured as a curved side surface of a truncated right circular cone.

Each collet segment 1200 has a radially outer collet segment contact surface 1210 that includes a first surface area 1211 and a second surface area 1212, the second surface area 1212 being axially contiguous with the first surface area 1211. The first and second surface regions 1211 and 1212 are configured to contact the collet receiver contact surface 1110, as described in more detail later herein. Each collet segment 1200 also has a radially inner workpiece engaging surface 1220, the engaging surface 1220 being suitably configured for gripping an outer surface of a tubular workpiece.

In fig. 3A, outer collet 1000 is shown with workpiece engaging surfaces 1220 of collet segments 1200 in clamping engagement with outer surface 1312 of workpiece 1302, outer surface 1312 of workpiece 1302 having an outer diameter corresponding to the largest outer diameter for which collet 1000 is designed to clamp. For the purposes of this disclosure, the position of the collet segment 1200 shown in fig. 3A, where the axial length of the contact area between the collet segment contact surface 1210 and the collet receiver contact surface 1110 is greatest, is referred to as the retracted position.

Figure 3B is an isometric view of the outer clamp head 1000 clampingly engaging a workpiece 1302 as shown in figure 3A.

In fig. 4A, the outer collet 1000 is shown with the workpiece engagement surface 1220 of the collet segments 1200 in clamping engagement with the outer surface 1311 of the workpiece 1301, the outer surface 1311 of the workpiece 1301 having an outer diameter corresponding to the smallest outer diameter that the collet 1000 is designed to clamp. For the purposes of this disclosure, the position of the collet segment 1200, i.e., the position where the axial length of the contact area between the collet segment contact surface 1210 and the collet receiver contact surface 1110 is minimal, is shown in fig. 4A, referred to as the extended position.

Figure 4B is an isometric view of the outer collet 1000 clampingly engaging a workpiece 1301 as shown in figure 4A.

Fig. 5A and 5B further illustrate an exemplary collet segment 1200 of the outer collet 1000. As previously described, each collet segment 1200 has a collet segment contact surface 1210 that includes first and second surface areas 1211 and 1212. The first surface region 1211 has an axial length LOC and is configured as a portion of a curved side surface of the OCC. The second surface area 1212 has an axial length LC and is configured as a portion of the curved side surface of a truncated right circular cone.

The axial length LC and radii RC1 and RC2 of the second surface area 1212 may be selected such that the configuration of the second surface area 1212 matches the configuration of the collet receiver contact surface 1110 when the collet segments 1200 are in their extended position. So selected, the taper angle of the second surface region 1212 will be equal to the taper angle of the collet receiver contact surface 1110.

The radius ROC of first surface region 1211 may be equal to radius RC1 of second surface region 1212. The angle of inclination of the OCC used to define the first surface area 1211 may be selected to be equal to the cone angle of the truncated right circular cone used to define the collet receiver contact surface 1110.

EXAMPLE #2 internal chuck mechanism

Fig. 6A and 7A are longitudinal cross-sectional views through an embodiment 2000 of an internal collet mechanism constructed according to the present disclosure. The inner collet 2000 has a longitudinal axis 2050 and includes a collet receiver 2100 and a segmented collet including a plurality of collet segments 2200. The collet receiver 2100 has an outer surface defining a collet receiver contact surface 2110, the collet receiver contact surface 2110 being configured as a curved side surface of a truncated right circular cone.

Each of the chuck segments 2200 has a radially inner chuck segment contact surface 2210 including a first surface area 2211 and a second surface area 2212, the second surface area 2212 being axially contiguous with the first surface area 2211. First and second surface areas 2211 and 2212 are configured to contact chuck receiver contact surfaces 2110, as described in more detail later herein. Each chuck segment 2200 also has a radially outer workpiece engaging surface 2220, the workpiece engaging surface 2220 suitably configured for gripping an inner surface of a tubular workpiece.

In fig. 6A, the inner collet 2000 is shown with the workpiece engaging surface 2220 of the collet segment 2200 in clamping engagement with the inner surface 2321 of the workpiece 2301, the inner surface 2321 of the workpiece 2301 having an inner diameter corresponding to the smallest inner diameter that the collet 2000 is designed to clamp. For the purposes of this disclosure, the position of the chuck segment 2200 shown in FIG. 6A, i.e., the position where the axial length of the contact area between the chuck segment contact surface 2210 and the chuck receiver contact surface 2110 is greatest, is referred to as the retracted position.

Figure 6B is an isometric view of the inner collet 2000 shown grippingly engaging a workpiece 2301 as in figure 6A.

In fig. 7A, the inner collet 2000 is shown with the workpiece engaging surface 2220 of the collet segments 2200 in clamping engagement with the inner surface 2322 of the workpiece 2302, the workpiece 2302 having the largest inner diameter for which the collet 2000 is designed to clamp. For the purposes of this disclosure, the position of the chuck segment 2200 shown in FIG. 7A, i.e., the position where the axial length of the contact area between the chuck segment contact surface 2210 and the chuck receiver contact surface 2110 is minimal, is referred to as the extended position.

Fig. 7B is an isometric view of the inner collet 2000 shown grippingly engaging a workpiece 2302.

Fig. 8A and 8B also illustrate an exemplary collet segment 2200 of the inner collet 2000. As previously described, each of the collet segments 2200 has a collet segment contact surface 2210 that includes first and second surface areas 2211 and 2212. First surface area 2211 has an axial length LOC and is configured as a portion of OCC. Second surface area 2212 is configured as a portion of the curved side surface of a truncated right circular cone.

The axial length LC and radii RC1 and RC2 of second surface area 2212 may be selected such that the configuration of second surface area 2212 matches the configuration of collet receiver contact surface 2110 when collet segment 2200 is in its extended position. So selected, the taper angle of second surface area 2212 will be equal to the taper angle of collet receiver contact surface 2110.

Radius ROC of first surface area 2211 may be equal to radius RC1 of second surface area 2212. The angle of inclination of the OCC used to define first surface area 2211 may be selected to be equal to the angle of taper of the truncated right circular cone used to define chuck receiver contact surface 2110.

EXAMPLE #3 Internally gripping casing running tool

Fig. 9A and 9B depict an internal gripping sleeve running tool (or "CRT") 3000 similar to the prior art tubular running tool shown in fig. 8 and 9 of WO 2010/006441, but incorporating an internal collet-type mechanism according to the present disclosure to grip a tubular sleeve workpiece 3300 having an inner surface 3310 and an outer surface 3320.

CRT3000 includes a mandrel 3100, mandrel 3100 serving as a collet receiver similar to collet receiver 2100 of internal collet mechanism 2000 herein. The configuration of the outer surface 3110 of the mandrel 3100 includes a plurality of truncated right circular cones.

The CRT3000 also includes an integral slip 3200 (alternatively also referred to herein as a slip element) as a collet segment. The integral slips 3200 have an outer surface 3220, the outer surface 3220 suitably configured to grip an inner surface 3310 of the casing 3300. As shown in fig. 9B and 10, the integrated slips 3200 have a plurality of inner surface regions 3210 that contact the outer surface 3110 of the mandrel 3100. Inner surface region 3210 is configured as an OCC surface. The angle of inclination of the OCC surface defining the inner surface region 3210 of the integral slips 3200 may be selected to be equal to the angle of taper of the truncated right circular cone defining the outer surface 3110 of the mandrel 3100.

EXAMPLE #4 externally gripping casing running tool

Fig. 11A and 11B depict an external clamp CRT4000 similar to the prior art tubular running tool disclosed in US7,909,120 and US 10,081,989, but incorporating an external collet-type mechanism according to the present disclosure to clamp a tubular casing workpiece 4300 having an inner surface 4310 and an outer surface 4320.

CRT4000 includes a mandrel 4100 that functions as a collet receiver similar to collet receiver 1100 of the external collet mechanism 1000 herein. The mandrel 4100 has an inner surface 4110, the inner surface 4110 being configured to define a plurality of truncated right circular cones.

The CRT4000 further comprises slip assemblies 4200 as collet segments, each slip assembly 4200 comprising a jaw 4201 and a die 4202. The inner surface 4220 on each mold 4202 of the slips 4200 is suitably configured to grip the outer surface 4320 of the casing 4300. As shown in fig. 11B and 12, the slips 4200 have a plurality of outer surface areas 4210 on the jaws 4201 that contact the inner surface 4110 of the mandrel 4100. Outer surface region 4210 is configured as an OCC surface. The angle of inclination of the OCC surface defining the outer surface region 4210 of the slips 4200 may be selected to be equal to the angle of taper of the truncated right circular cone defining the inner surface 4110 of the mandrel 4100.

Those skilled in the art will readily appreciate that various modifications may be made to the embodiments in accordance with the present disclosure without departing from the scope of the present teachings, such as, but not limited to, modifications that may use equivalent materials hereafter conceived or developed, segmented collets having different numbers of collet segments, or collets configured to engage workpieces of different sizes or configurations. It should be expressly understood that the scope of the present disclosure is not intended to be limited to the embodiments described or illustrated, and that substitution of variations in the elements or features claimed or illustrated will not constitute a departure from the scope of the present disclosure without any substantial resulting change in function.

In this patent document, any form of the word "comprising" is to be understood in its non-limiting sense, meaning that any element or feature following the word is included, but elements or features not specifically mentioned are not excluded. The reference to an element or feature by the indefinite article "a" does not exclude the possibility that more than one of such element or feature is present, unless the context clearly requires that one and only one of such element or feature be present. The use of any form of the terms "connect," "engage," "couple," "attach," or any other term describing an interaction between elements is not meant to limit the interaction to direct interaction between the subject elements, and may also include indirect interaction between elements, such as through auxiliary or intermediate structures.

Relational and conformational terms such as "perpendicular," "parallel," "cylindrical," and "equal" are not intended to denote or require absolute mathematical or geometric precision. Accordingly, these terms should be understood to mean or require only a relatively high degree of precision (e.g., "substantially vertical"), unless the context clearly requires otherwise. Wherever used in this document, the terms "exemplary" and "typically" should be interpreted in a manner that represents common usage or practice, and should not be construed as implying essential or non-uniformity.

List of elements shown

Description of the element number

100 external collet type mechanism

110 chuck receiver

111 collet receiver surface of contacting segmented collet ("collet receiver contact surface")

120 chuck segment

121 contact surface of collet segment of collet receiver ("collet segment contact surface")

200 internal collet type mechanism

210 collet receiver

211 contact surfaces of a collet receiver of a segmented collet ('collet receiver contact surfaces')

220 chuck segment

221 surface of the collet section that contacts the collet receiver ("collet section contact surface")

1000 external collet type mechanism

1050 longitudinal axis of external collet-type mechanism

1100 chuck receiver

1110 contact the surface of the collet receiver of the segmented collet (the "collet receiver contact surface")

1200 collet segment

1210 surfaces of the collet segments that contact the collet receiver ("collet segment contact surfaces")

1211 inclined cylindrical region of surface 1210

1212 surface 1210 right circular cone region

1220 surface of the segmented collet contacting the workpiece ("workpiece engaging surface")

1301 the chuck 1000 is designed to clamp a workpiece having a minimum outer diameter

1311 outer surface of work piece 1301

1321 inner surface of workpiece 1301

1302 the chuck 1000 is designed to clamp a workpiece having a maximum outer diameter

1312 outer surface of workpiece 1302

1322 inner surface of workpiece 1302

2000 internal collet type mechanism

2050 longitudinal axis of internal collet-type mechanism

2100 collet receiver

2110 contact surfaces of the collet receiver of the segmented collet ("collet receiver contact surfaces")

2211 cylindrical region of surface 2210

Right circular conical region of 2212 surface 2210

2200 collet segment

2210 contacts a surface of a cartridge segment of the cartridge receiver ("cartridge segment contact surface")

2220 surface of the segmented collet that contacts the workpiece (the "workpiece engaging surface")

2301 the collet 2000 is designed to hold a workpiece having a minimum outer diameter

2311 outer surface of workpiece 2301

2321 inner surface of workpiece 2301

2302 the collet 2000 is designed to hold a workpiece having a maximum outer diameter

2312 outer surface of workpiece 2302

2322 the inner surface of the workpiece 2302

3000 internal clamping sleeve running tool

3100 mandrel

3110 surfaces contacting a mandrel of the integrated slip

3200 integrated slips ('slips element')

3210 surface of the integrated slip contacting the mandrel

3220 surface of integral slip gripping a casing

3300 casing tube

3310 outer surface of cannula 3300

3320 inner surface of the sleeve 3300

4000 external gripping casing running tool

4100 mandrel

4110 contacting a surface of a mandrel of a slip

4200 slip assembly

4201 claw

4202 die

4210 surfaces of slips on jaws contacting a mandrel

4220 surface of slips on a mold for gripping casing

4300 casing pipe

4310 outer surface of sleeve 4300

4320 inner surface of sleeve 4300