Rod coupler and coupled rod assembly

Abstract

A coupling (118) for a drill rod (116) includes a body defining an internal bore (204) extending along a longitudinal axis (208), at least a portion of the internal bore defining a non-circular profile having a plurality of flats (228) including a first pair of adjacent flats defining a vertex therebetween. A cross bore (252) of the body has a central axis (258) perpendicular to and offset from the longitudinal axis (208). A radially innermost portion of the cross bore extends perpendicular to a reference line extending from the longitudinal axis to the vertex.

Description

[0001] Related applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 62 / 818,199, filed March 14, 2019, the entire contents of which are incorporated herein by reference. Background Technology

[0003] This invention relates to connecting rods together by a torque transmission relationship. The invention further relates to an assembly for connecting rods, which in some embodiments can be used in horizontally oriented drilling systems.

[0004] Twin-drill-pipe systems, including inner and outer rods, are known for directional drilling. A typical twin-drill-pipe system is configured to advance a series of drill pipes connected end-to-end to form a drill string into the ground. At the end of the drill string is a rotating drill bit or tool. Twin-drill-pipe systems typically include a first drive mechanism for controlling the rotation of the drill bit and a second drive mechanism for controlling the rotation of a steering element. Summary of the Invention

[0005] This invention addresses how to retain a connector on the inner rod of a twin-rod drill pipe assembly. In this inner rod design, it is crucial to maximize the flow path of the drilling fluid flowing in the annular space between the inner and outer rods. Therefore, the connector design must consider rod retention characteristics that significantly influence the internal characteristics of the connector, flow maximization characteristics that significantly influence the external characteristics of the connector, and the interaction between these two characteristics. Sufficient strength and fatigue life must be achieved to transmit torque and longitudinal forces while still ensuring adequate fluid flow.

[0006] In one aspect, the present invention provides a connector for a drill pipe. The connector includes a body defining an inner bore extending along a longitudinal axis, at least a portion of which defines a non-circular profile having a plurality of planes, the plurality of planes including a first pair of adjacent planes defining a vertex therebetween. An intersecting orifice of the body has a central axis perpendicular to and offset from the longitudinal axis. The radially innermost portion of the intersecting orifice extends perpendicular to a reference line extending from the longitudinal axis to the vertex.

[0007] On the other hand, the present invention provides a connector for drill pipe. The connector includes a body defining an inner bore and a cross-hole. The inner bore extends along a longitudinal axis, and at least a portion of the inner bore defines a non-circular profile. The cross-hole has a central axis perpendicular to and offset from the longitudinal axis. The body defines an outer peripheral surface, and at an axial position of the cross-hole, the outer peripheral surface is non-circular and includes a convex angle through which the cross-hole is formed.

[0008] Other aspects of the invention will become apparent from consideration of the detailed description and accompanying drawings. Attached Figure Description

[0009] Figure 1 A schematic side view of a drilling rig and drill string according to an embodiment of the present invention is shown.

[0010] Figure 2 A perspective view of a drilling rig according to an embodiment of the present invention is shown.

[0011] Figure 3 Show Figure 2 Another perspective view of the drilling rig.

[0012] Figure 4 A perspective view of a drill pipe assembly according to an embodiment of the present invention is shown.

[0013] Figure 5 Show Figure 4 A partial sectional view of the side of a pair of connected drill pipe assemblies.

[0014] Figure 6 A side view of the connector removed from the inner rod is shown.

[0015] Figure 7 It is a cross-sectional view showing the engagement between the retaining pin in the connector and the notch in the inner rod.

[0016] Figure 8 schematically shown Figure 5 The connector and inner rod, as well as the associated engagement between the retaining pin and the inner rod, have a hexagonal torque transmission interface.

[0017] Figure 9 An alternative embodiment of the connector and inner rod is shown, wherein the retaining pin is located on the connector at a position where torque transmission can occur.

[0018] Figure 10 Another alternative embodiment of the connector and inner rod is shown, wherein the retaining pin is further positioned along the connector such that the connector includes one or more protrusions or convex corners that receive the retaining pin.

[0019] Figure 11 yes Figure 10 A perspective view of an embodiment.

[0020] Figure 12 It shows that it is aimed at Figure 10 and Figure 11 A cross-sectional view of the engagement between the retaining pin and the recess in the inner rod in the embodiment of the connector.

[0021] Figure 13 Showing with Figure 10 Another similar embodiment, but in which a replaceable wear ring is provided in addition to the connector.

[0022] Figure 14 Another embodiment of the rod connector arrangement is shown.

[0023] Figure 15 yes Figure 14 A cross-sectional view of the device passing through the retaining pin.

[0024] Figure 16 Another embodiment of the rod connector arrangement is shown.

[0025] Figure 17 The diagram schematically illustrates an inner rod and connector with a pentagonal torque transmission interface, as well as the associated engagement between the retaining pin and the inner rod.

[0026] Figure 18 The diagram schematically illustrates an inner rod and connector with a heptagonal torque transmission interface, as well as the associated engagement between the retaining pin and the inner rod.

[0027] Figure 19 This illustration shows another alternative embodiment of the connector without a protrusion or convex angle for accommodating a retaining pin. In addition to the connector, a replaceable wear ring is also provided.

[0028] Figure 20 yes Figure 19 A perspective assembly diagram of an embodiment shows the connector and retaining pin separated from the inner rod.

[0029] Figure 21 It is along Figure 19 A cross-sectional view taken by line 21-21 through the cross hole of the connector.

[0030] Figure 22 This is a perspective view of yet another alternative embodiment of the connector with an amplified portion.

[0031] Figure 23 yes Figure 22 A perspective view of an embodiment, in which the connector and retaining pin have been removed to illustrate the construction of the internal drill pipe. Detailed Implementation

[0032] Before explaining any embodiment of the invention in detail, it should be understood that the invention is not limited to the application of the details of its construction and component arrangement set forth in the following description or shown in the following drawings. The invention can have other embodiments and can be practiced or implemented in various ways.

[0033] Figures 1-4 A dual-rod drilling system 100 is shown. The dual-rod drilling system 100 includes a drill string 102, which is introduced into the ground 101 by a drilling rig 104. Figure 1 An example of drill string 102 is shown.

[0034] The drilling rig 104 includes a prime mover 122 (e.g., a diesel engine), a gearbox 124, a rack 126, and a disconnection mechanism 128 (e.g., a vise system). Optionally, the drilling rig 104 may include a drill pipe storage box 130, an operator station 132, and a set of tracks or wheels 134.

[0035] The drill string 102 consists of separate sections of a drill pipe assembly 106 connected to the drill rig 104 at the upward end 108 and to the drill bit 110 at the downward end 112. Each drill pipe assembly 106 ( Figure 4 It includes a downward-facing end 109 and an upward-facing end 111. The drill pipe assembly 106 is strung together end to end to form a drill string 102, which can extend a considerable distance in some drilling applications.

[0036] Each drill pipe assembly 106 includes a tubular outer drill pipe 114, one end of which has an external thread and the other end has an internal thread. In some examples, the drill pipe assembly 106 and the associated drill rig 100 are configured such that, during the construction of the drill string 102, the external thread of the outer drill pipe 114 is positioned at the upward bore end 111 of the drill pipe assembly 106 and the internal thread of the outer drill pipe 114 is positioned at the downward bore end 109 of the drill pipe assembly 106.

[0037] Each drill pipe assembly 106 also includes a smaller inner drill pipe 116, such as Figure 2 and Figure 3 As shown in the cross-sectional view, the inner drill pipe 116 is assembled within the tubular outer drill pipe 114. The inner drill pipe 116 of each drill pipe assembly is interconnected with the adjacent inner drill pipe via an inner rod connecting device 118. In some examples, each inner rod connecting device 118 is secured to each inner drill pipe 116 at the upward bore end 111 of each drill pipe assembly 106.

[0038] During drilling operations, the drill rig 104 individually removes drill rod assemblies 106 from the drill rod storage box 130 and moves each drill rod assembly 106 onto the rack 126. Once positioned on the rack 126, the disconnect mechanism 128 and the gearbox 124 engage the drill rod assembly 106 and connect it to the immediately preceding downward drill rod assembly 106. Once engaged, the gearbox 124 is configured to travel longitudinally toward the disconnect mechanism 128 on the rack 126 while simultaneously rotating one or both of the outer drill rod 114 and the inner drill rod 116 of the drill rod assembly 106. When the gearbox 124 reaches the disconnect mechanism 128 at the end of the rack 126, the gearbox 124 disengages from the drill rod assembly 106, thereby disengaging from the drill string 102, and retracts the rack 126 upward so that another drill rod assembly 106 can be added to the drill string 102. The process is repeated until the drilling operation is completed, and then reversed during the pullback operation, in which the drill rig 104 removes the drill rod assembly 106 from the ground 101.

[0039] Figure 5 This is a cross-sectional view showing two drill pipe assemblies 106 connected together, and Figure 6 The connector 118 is shown being removed from the inner rod 116. Figure 7 yes Figure 5 A cross-sectional view taken through retaining pin 256. (Refer to...) Figures 5-7 The connector 118 includes a body 200 made of a suitable metallic material (e.g., steel) for connecting two adjacent solid inner rods 116 together in a manner that allows torque transmission between two adjacent inner rods 116. The body 200 defines an inner bore 204, which, in the illustrated embodiment, extends the entire length of the connector 118. The bore 204 defines a longitudinal axis 208 extending in the longitudinal or axial direction of the connector 118. Although the illustrated embodiment shows solid inner rods 116, and while the features of the invention are well-suited for use with drill pipe assemblies having solid inner rods, it should be understood that the invention can also be used with drill pipe assemblies having hollow inner rods.

[0040] The body 200 includes a first portion or main portion 212 and a second portion or enlarged portion 216 longitudinally spaced from the main portion 212. The main portion 212 forms a first axial region of the body 200, and the enlarged portion 216 forms a second axial region of the body 200 adjacent to the first axial region. A small transition portion 218 may be provided between the main portion 212 and the enlarged portion 216, but the transition portion 218 can be considered as part of the enlarged portion 216. In this embodiment, the inner profile of the hole 204 in the main portion 212 differs from the inner profile in the enlarged portion 216. More specifically, the inner hole 204 at the main portion 212 has a non-circular profile configured to match a non-circular profile at the end of the inner rod 116, so as to be fitted onto the adjacent inner rod 116 in a torque-transmitting relationship. The shape of the non-circular profile shown is hexagonal (see also...). Figure 8 However, other non-circular shapes can also be used. A non-circular outline can consist of multiple distributed flat sides and can be polygonal, especially regular polygonal outlines, such as pentagons (see...). Figure 17 ), heptagon (see Figure 18Hexagons, squares, etc. Adjacent flat edges are adjacent at vertices, and it should be understood that vertices may be partially rounded so that the true geometric vertices formed between the flat edges do not lie on the surface defining the non-circular profile. Regarding rod 116, the hexagonal profile includes adjacent outer surface portions or planes 220 that intersect at corresponding edges or corners 224. Regarding the inner profile of the non-circular hole 204, the hexagonal profile includes adjacent inner surface portions or planes 228 that intersect at corresponding inner vertices 232. For simple polygonal shapes, vertex 232 is a point located on the surface of hole 204. However, (e.g., due to edge rounding during manufacturing) it is conceivable that vertex 232 could be a theoretical intersection not located on the surface of hole 204. The main portion 212 shown can be made by drilling a non-circular profile into the hole of the tube blank. The outer peripheral surface 234 of the main portion 212 is shown as cylindrical and uninterrupted. This facilitates the flow of drilling fluid between the outer peripheral surface 234 of the main portion 212 and the inner surface of the outer rod 114.

[0041] The enlarged portion 216 shown has an inner hole 204 with a circular / cylindrical profile, the diameter of which is large enough to not engage with or otherwise interfere with the non-circular outer profile of the rod 116 to which the connector 118 is attached. Therefore, the enlarged portion 216 is considered the non-torque-transmitting portion of the connector 118. Figure 5 As shown, the distal end 236 of the enlarged portion 216 abuts against and engages the distal end 240 of the outer rod 114. To allow and facilitate the flow of drilling fluid between the inner rod 116 and the outer rod 114, one or more fluid flow openings 244 are formed in the enlarged portion 216 (see Figure 1). Figure 6 In the illustrated embodiment, two diametrically opposed slots 244 are formed in the enlargement 216 to provide communication between the inner bore 204 and the outer peripheral surface 248 of the enlargement 216. The outer peripheral surface 248 of the enlargement 216 is generally cylindrical unless interrupted by the presence of the fluid flow opening 244.

[0042] The outer peripheral surface 248 of the enlarged portion 216 is also interrupted by the presence of one or more intersecting openings 252 formed in the enlarged portion 216. The intersecting openings 252 are configured to receive corresponding retaining pins 256 that operate to axially or longitudinally secure the connector 118 relative to one of the coupled inner rods 116. This ensures that the connector 118 does not separate from the inner rod 116 before or after the engagement process with the adjacent inner rod 116. While the illustrated embodiment utilizes two intersecting openings 252 to retain two pins 256 respectively, other embodiments may use only a single opening 252 and a single pin 256.

[0043] The cross orifice 252 can be considered "crossing" because it provides a passage through the connector 118 that passes through or across a portion of the inner bore 204. Each cross orifice 252 includes a respective central axis 258, which is perpendicular to and offset from the longitudinal axis 208. The axes 258 of the two illustrated cross orifices 252 are parallel to and equidistant from the longitudinal axis 208. Figure 7 As best shown, each cross-hole 252 provides a passage for the pin 256, such that when the pin 256 is installed in the cross-hole 252, the pin 256 extends at least partially into and through the inner bore 204. It can be seen that the cross-hole 252 is spaced apart from the longitudinal axis 208 (e.g., opposite), such that only a portion of each pin 256 passes through or intersects the inner bore 204. Meanwhile, another portion at the same circumferential location lies radially outside the inner bore 204. This relationship will be discussed further below. With this configuration, the pin 256 only interferes with the outermost portion of the non-circular outer contour of the inner rod 116. To accommodate the pin 256 and to enable the pin 256 to axially hold the connector 118 relative to the rod 116, the rod 116 includes a plurality of recesses 260 formed in the non-circular outer contour of the inner rod 116. Figures 5-7 As shown, a notch 260 is formed by removing material from each edge or corner 224 at an axial location along the rod 116. Each notch 260 has a truncated cylindrical cross-sectional shape that approximates the outer contour of the retaining pin 256 to partially receive the outer contour, although other cross-sectional shapes are optional. Each notch 260 extends perpendicular to the longitudinal axis 208 such that the notch 260 receiving the retaining pin 256 during assembly extends parallel to or coincides with the central axis 258 of the cross-hole 252. The notch 260 provides one example of a notch in the outer contour of the inner rod 116 for interaction with the retaining pin 256, but other embodiments are also contemplated, some of which are the subject of later sections of the invention.

[0044] In the illustrated embodiment, the depth of the notch 260 is such that the notch 260 does not cut into the inscribed circle 264 within the non-circular profile (e.g., a hexagonal profile) defined by the inner rod 116 (see [link to documentation]). Figure 8The inscribed circle 264 is the largest circle that fits into the non-circular profile, for example, tangent to but not intersecting with plane 228. In other embodiments, the notch 260 may have an overlapping depth between circumferentially adjacent notches 260. In still other embodiments, a single notch may extend to form a circumferential groove. With respect to pin 256, the depth of notch 116 entering the corner 224 of rod 116 at its deepest point may be 0.25 to 0.6 times the diameter of pin 256. Although only a single notch 260 may be formed for each pin 256, forming a notch 260 at each corner 224 enables rods 116 to be joined, regardless of the angular orientation of one rod 116 relative to an adjacent joined rod 116.

[0045] The pin 256 shown is a solid pin, but a hollow roller pin can also be used. Alternatively, different materials (e.g., bronze, plastic, etc.) can be selected for the pin 256 to achieve the desired failure mode. Specifically, if axial force or thrust between the connector 118 and the rod 116 causes damage to the assembly, it is preferable that the pin 256 fails (e.g., pin shearing) rather than that the pin is damaged (e.g., sheared or chipped) at angle 224 of the rod 116.

[0046] By positioning the cross-hole 252 and pin 256 within the enlarged portion 216—in this embodiment, the enlarged portion is not the torque transmission portion of the connector 118—the number of stress-increasing portions in the main portion 212, which is the torque transmission portion of the connector 118, is reduced. Furthermore, this positions the cross-hole 252 and pin 256 outside the area transmitting torsional and bending loads. This extends the fatigue life of the connector 118 compared to designs that may include one or more retaining features (e.g., pins) in the main torque transmission portion 212. Additionally, the structural integrity of the rod 116 is improved by using only smaller, different notches 260, compared to arrangements requiring more material removal at the rod ends.

[0047] pass Figures 5-7 The illustrated embodiments provide various structural and geometric relationships. First, note that at least 25% of the outer peripheral surface 234 of the main portion 212 is spaced from the longitudinal axis 208 by no more than a first distance D1 (see...). Figure 6This could be a case where a stabilizer is positioned around the outer peripheral surface 234. In some embodiments, at least 50% of the outer peripheral surface 234 of the main portion 212 is spaced from the longitudinal axis 208 by a first distance D1. As shown, the entirety (i.e., 100%) of the outer peripheral surface 234 of the main portion 212 is spaced from the longitudinal axis 208 by a first distance D1. For example, the outer peripheral surface 234 may be defined as a cylindrical surface with a radius equal to the first distance D1. The aforementioned percentage may be taken relative to the entirety of the outer peripheral surface 234 from one axial end to the other, or alternatively may refer to the shape of the outer peripheral surface at a particular axial location, such as a finite axial length segment or a cross-section taken perpendicular to the longitudinal axis 208 at a single axial location. The first distance D1 is chosen to maximize the flow rate of drilling fluid within the annular space between the inner rod 116 and the outer rod 114, while ensuring sufficient wall thickness of the connector 118 at the torque transmission portion. Furthermore, at least 5% of the outer peripheral surface 248 of the enlarged portion 216 is spaced from the longitudinal axis 208 by a distance greater than the first distance D1. As shown, the entire outer peripheral surface 248 of the enlarged portion 216 is spaced from the longitudinal axis 208 by a distance greater than a first distance D1. For example, the outer peripheral surface 248 may be defined as a cylindrical surface having a radius greater than the first distance D1. Again, a fluid flow opening 244 is provided to receive drilling fluid flow. It can be said that distance D1 is a distinguishing or descriptive factor between the connector 118 as a main portion 212 or as part of the enlarged portion 216. As described below with reference to other embodiments, the following portion of the connector can be considered an enlarged portion: this portion of the connector has some portions of its outer peripheral surface spaced from the longitudinal axis 208 by a distance greater than D1, even when adjacent portions of the outer peripheral surface in the same plane or circumferential segment are spaced from the longitudinal axis 208 by no more than distance D1. As observed by those embodiments, the cross orifice 252 is located in such an enlarged portion.

[0048] Reference Figure 7 and Figure 8 There is another relationship between the cross-hole 252 and the inner hole 204. Figure 7 It is a cross-section taken from the enlarged portion 216 that is perpendicular to the longitudinal axis 208 and passes through the central axis 258 of the pin 256, and Figure 8 It is similar to Figure 7 A schematic diagram. The non-circular profile of the inner hole 204 includes a minimum distance D measured from the longitudinal axis 208. min and the maximum distance D measured from the longitudinal axis 208 max In the simple polygonal profile of hole 204 shown in the figure, find the minimum distance D at the center of each plane 228. min And find the maximum distance D at each internal vertex 232. maxThe cross opening 252 is positioned relative to the hole 204 such that a dashed line L extending parallel to the central axis 258 and positioned along the radially innermost surface of the cross opening 252 is spaced apart from the longitudinal axis 208 by a distance D. L The distance D L Equal to or greater than the minimum distance D min But less than the maximum distance D max In other words, the straight line L lies on or radially outside the inscribed circle 264. This relationship stems from the dimensions and depth of the notch 260, and the determination of the minimum amount of interference required to adequately secure the connector 118 to the rod 116 through engagement or interference between each pin 256 and the notch 260. See also Figure 17 and Figure 18 It can be seen that this relationship holds regardless of the specific non-circular profile. Those skilled in the art will understand, based on this relationship, how the amount of interference between each pin 256 and notch 260 will decrease as the number of sides of the polygonal profile increases. It should also be noted that the straight line L, and therefore the radially innermost surface of the intersecting aperture 252, is perpendicular to the maximum measured distance D. max The straight line along which it extends. In other words, the straight line L is perpendicular to the baseline R. L A second straight line L extends from the longitudinal axis 208 through a vertex between a pair of adjacent planes 228. For the second cross-hole 252, a second straight line L extends perpendicularly to the second reference line from the longitudinal axis 208 through a second vertex between the second pair of adjacent planes 228. In the case of cross-holes 252 opposite each other in the diametrical direction, the two reference lines R... L Align them and make them parallel to the straight line L on the innermost radial surface of the two intersecting orifices 252.

[0049] Figure 9 Showing something similar to Figures 5-7 The alternative embodiment shown, however, involves moving the positions of the cross opening 252 and the notch 260 relative to the connector 118 and the rod 116. Specifically, as... Figure 9 As shown, the cross-hole 252 moves axially toward the main part 212 (in Figure 9 (From center to right), and the notch 260 moves a corresponding distance toward the end of the rod 116. In the position shown, the cross orifice 252 positions the pin 256 into the torque transmission portion of the connector 118. Thus, the pin 256 intersects or engages with the inner rod 116 in an axial position, where the inner contour of the connector 118 matches the outer contour of the rod 116, causing the pin 256 to be subjected to shear more directly and reducing or eliminating bending loads on the pin 256. Although the hole 252 is shown in the transition portion 218, this position in the transition portion includes the non-circular torque transmission profile of the inner hole 204.

[0050] Figures 10-12 Another embodiment is shown, wherein the positions of the cross opening 252 and the notch 260 relative to the connector 118 and the rod 116 are... Figure 9 The movement extends further. In this embodiment, the connector 118a is modified to include a protrusion or projection 300 formed relative to the initial main portion 212 of the connector 118. These protrusions 300 provide additional material to receive / support the cross-hole 252, thereby making the portion of the connector 118a containing the protrusions 300 considered as the enlarged portion 216a. Figure 12 As seen, the convex angle 300 gives the outer peripheral surface of the connector 118a a generally elliptical shape in a cross-section taken through the convex angle 300 and perpendicular to the longitudinal axis 208. Of course, other geometries with consideration for the additional material required for the cross-hole 252 and the desired configuration to maximize fluid flow in the annular space between the inner rod 116 and the outer rod 114 can also be used for the convex angle. The connector 118a also includes an enlarged portion 304 at one distal end for engaging the distal end of the outer rod 114. Figure 11 As shown, the enlarged portion 304 includes four fluid flow openings 244.

[0051] Although the convex angle 300 is more than a distance D1 from the longitudinal axis 208, the remaining portion of the outer circumferential surface in the axial section including the convex angle 300 is no more than a distance D1 from the longitudinal axis 208, thus providing sufficient drilling fluid flow. In the illustrated embodiment, 5% or more of the outer circumferential surface 248a of the enlarged portion 216a is spaced from the longitudinal axis 208 by a distance greater than the first distance D1, and more specifically, this amount can be between 20% and 40%. The convex angle 300 extends over approximately one-third of the circumference of the enlarged portion 216a, such that approximately 33% of the outer circumferential surface 248a of the enlarged portion 216a is spaced from the longitudinal axis 208 by a distance greater than the first distance D1. The remaining 67% or two-thirds of the outer circumferential surface 248a is no more than a distance D1 from the longitudinal axis 208, allowing drilling fluid to still flow freely axially through the convex angle 300. Typically, the portion of the outer peripheral surface 248a of the enlarged portion 216a that is greater than the first distance D1 in distance from the longitudinal axis 208 should be kept as small as possible, and in some embodiments may be less than 33% or less than 20%. Figure 11 As best shown, the smaller diameter portion of the outer peripheral surface 248a of the enlarged portion 216a smoothly merges or deforms with the outer peripheral surface 234a of the main portion 212a on either axial side of the enlarged portion 216a. The same relationship described above regarding the distance to the dashed line L extending parallel to the central axis 258 and located at the radially innermost surface of the cross-hole 252 also applies to this embodiment.

[0052] Figure 13 Showing with Figures 10-12Another embodiment similar to the one shown differs in that a separate wear ring 308 is provided instead of an integral enlargement 304 with connector 118a. Connector 118b has a shorter axial length to accommodate the wear ring 308, but is otherwise identical to connector 118a up to the enlargement 304. The separate wear ring 308 provides a separate replaceable component that can be replaced upon wear, without requiring replacement of connector 118b. As shown, the wear ring 308 has an inner bore having a torque-transmitting portion (e.g., a non-circular profile) and a non-torque-transmitting portion (e.g., a cylindrical profile). The wear ring 308 includes one or more fluid flow openings 244.

[0053] Figure 14 and Figure 15 Another embodiment is shown, which is somewhat similar to Figure 13 In this embodiment, the outer circumferential surface of the connector 118c is not generally circular / cylindrical but includes opposing planes 312 extending the length of the connector 118c. With this design, the distance D1 from the longitudinal axis 208 can be measured at plane 312, which can be considered the main portion 212c of the connector 118c, and the two portions of the connector 118c that receive the pin 256 will be considered the enlarged portions 216c. Unlike previous embodiments where the main portion and the enlarged portions are axially spaced apart from each other and surround the entire circumferential section around the longitudinal axis 208, in this embodiment, the main portion 212c and the enlarged portion 216c are circumferentially spaced apart from each other, and each can extend the entire axial length of the connector 118c. Plane 312 will provide a suitable fluid flow area. In some embodiments, the enlarged portion 216c may not extend the entire axial length of the connector 118c to provide additional fluid flow area.

[0054] Figure 16 Another embodiment is shown in which the connector 118d does not include any enlarged portion. Instead, the connector 118d consists only of a main portion 212, which is cylindrical in the illustrated configuration. To accommodate the retaining pin 256, the rod 116 is turned downward at one end to include a notch in the form of a groove or channel 316 that receives the pin 256. In this embodiment, the entire width (e.g., diameter dimension) of the pin 256 passes through the inner hole 204 at least within the central portion of the pin's length. A connector similar to this device is described in U.S. Patent Application Publication No. 2018 / 0313169A1, published November 1, 2018.

[0055] exist Figures 19-21 In the embodiments, the connector 118e is similar to Figure 16The connector 118e does not have a protrusion or bevel to accommodate the retaining pin 256. Instead, the entire connector 118e consists only of a main part 212 (e.g., cylindrical), in which a cross-hole 252 is provided. In addition to the connector 118e, a replaceable wear ring 308 is also provided. Instead of a large, complete groove or channel 316 in the inner rod 116, Figures 19-21 The inner rod 116 includes smaller, individual notches 260 at one or more circumferential locations. The notches 260 are formed across an edge or corner 224 formed between a pair of adjacent planes 220. Similar notches 260 may be formed at each corner 224. Figure 21 As shown, the relationship between the inner hole 204 and the intersecting opening 252 can be similar to that described above. Figure 7 and Figure 8 The described relationship. Specifically, the central axis 258 of the cross aperture 252 is perpendicular to and offset from the longitudinal axis 208, and the radially innermost portion of the cross aperture 252 extends perpendicularly to the reference line RL extending from the longitudinal axis 208 to the vertex 232 between adjacent planes 228. Furthermore, the non-circular profile of the inner hole 204 has a defined minimum distance D from the longitudinal axis 208. min The first part and the maximum distance D from the longitudinal axis 208 max The second part, and the innermost radial portion of each cross opening 252 is spaced a certain distance from the longitudinal axis 208, which is equal to or greater than the minimum distance D. min And less than the maximum distance D max .

[0056] exist Figure 22 and Figure 23 In one embodiment, the connector 118f includes one or more cross orifices 252 located within the enlargement 216. Therefore, the cross orifices 252 and corresponding retaining pins 256 are located near the inner end of the connector 118f opposite to the distal end (the inner and distal ends are defined relative to the inner rod 116 axially held by the connector 118f, not by an additionally connected inner rod (not shown)). The cross orifices 252 and retaining pins 256 are located in a common axial position with one or more fluid flow openings 244. Furthermore, in Figure 23 As shown, the notch 260 in the inner rod 116 is located axially at the transition between a first segment (e.g., a distal segment) having a non-circular outer contour with a plane 220 and edges or corners 224 and a second segment (e.g., a proximal or other inner segment) having a different outer contour. The outer contour of the second segment may be circular, such that the second segment is a cylindrical segment of the inner rod. Other aspects of the arrangement of the cross-hole 252 relative to the inner hole 204 follow the foregoing description. Due to the axial arrangement of the notches 260, each notch is only on one axial side, rather than as... Figure 5 , Figure 9 , Figure 10 , Figure 13 , Figure 14 and Figure 20 The image shows edges or corners 224 defined on both axial sides. For example... Figure 16 As shown, this positioning can also be employed by the inner rod 116 with different types of retaining pin notches. This typically results in... Figure 16 The axial direction of the structure shown is reversed. Figure 16 The groove or channel 316 is defined at the distal end by a circular or cylindrical section and is only connected to the inner axial side by a non-circular outer contour having a plane 220 and an edge or corner 224.

[0057] Various features and aspects of the present invention are set forth in the following claims.

Claims

1. A connector for drill pipe, the connector comprising: Subject, the subject being defined as: An inner hole extending along a longitudinal axis, at least a portion of which defines a non-circular profile having a plurality of planes, the plurality of planes including a first pair of adjacent planes defining vertices therebetween, and A cross-shaped opening having a central axis that is perpendicular to and offset from the longitudinal axis, wherein the innermost radial portion of the cross-shaped opening extends perpendicularly to a reference line extending from the longitudinal axis to the apex.

2. The connector according to claim 1, wherein, The plurality of planes of the non-circular profile include four or more planes distributed in a uniform pattern around the longitudinal axis.

3. The connector according to claim 1, wherein, The plurality of planes of the non-circular profile include six planes of equal length configured to receive a hexagonal drill pipe.

4. The connector according to claim 1, wherein, The non-circular profile has a first portion defining a minimum distance from the longitudinal axis and a second portion defining a maximum distance from the longitudinal axis, wherein the radially innermost portion of the cross aperture is spaced from the longitudinal axis at a distance equal to or greater than the minimum distance and less than the maximum distance.

5. The connector according to claim 1, wherein, The main body includes: a) a primary portion having an outer peripheral surface, at least 25% of which is spaced from the longitudinal axis by no more than a first distance; and b) an enlarged portion at an axial position different from the primary portion. Wherein, at least 5% of the outer peripheral surface of the enlarged portion is spaced from the longitudinal axis by a distance greater than a first distance, and The cross opening is located in the enlarged portion of the main body.

6. The connector according to claim 5, wherein, The enlarged portion of the body includes one or more fluid flow openings, which are formed to extend between the outer peripheral surface and the inner bore of the enlarged portion.

7. The connector according to claim 5, wherein, The distance between the entire outer peripheral surface of the main part and the longitudinal axis does not exceed the first distance.

8. The connector according to claim 7, wherein, The outer peripheral surface is a cylindrical surface with a radius equal to the first distance.

9. The connector according to claim 1, wherein, The plurality of planes also include a second pair of adjacent planes defining a second vertex therebetween, and the connector also includes a second cross aperture having a central axis perpendicular to and offset from the longitudinal axis, wherein the radially innermost portion of the second cross aperture extends perpendicularly to a second reference line extending from the longitudinal axis to the second vertex.

10. The connector according to claim 9, wherein, The central axes of the first and second cross openings are parallel to and equidistant from the longitudinal axis.

11. The connector according to claim 1, wherein, The body defines a cylindrical outer peripheral surface extending through most of the axial length of the body, and wherein the intersecting opening is located at an axial position within most of the axial length of the cylindrical outer peripheral surface.

12. The connector according to claim 1, wherein, The body defines an outer peripheral surface, wherein, at the axial position of the cross opening, the outer peripheral surface is non-circular and includes a convex angle through which the cross opening is formed.

13. A connection system for a twin-rod drilling system, the connection system comprising: The connector of claim 1; Internal drill pipe, the internal drill pipe comprising: A torque transmission section having a non-circular outer contour, the torque transmission section being configured to mate with the non-circular contour of the connector's inner bore; and The notch formed in the non-circular outer contour; and A pin is positioned within the cross-hole of the connector and at least partially within the notch of the inner drill rod to secure the inner drill rod relative to the connector in the direction of the longitudinal axis.

14. The connection system according to claim 13, wherein, The notch is a notch that extends only through the corner formed between a pair of adjacent surfaces of the non-circular outer contour.

15. A connector for drill pipe, the connector comprising: Subject, the subject being defined as: An inner hole extending along a longitudinal axis, at least a portion of which defines a non-circular profile, and A cross-shaped opening having a central axis that is perpendicular to and offset from the longitudinal axis. The main body defines an outer peripheral surface, and at the axial position of the cross opening, the outer peripheral surface is non-circular and includes a convex angle through which the cross opening is formed.

16. The connector according to claim 15, wherein, The cross opening is a first cross opening, and the connector further includes a second cross opening having a central axis that is perpendicular to and deviates from the longitudinal axis at the axial position of the first cross opening, and wherein the outer peripheral surface includes a second convex angle through which the second cross opening is formed.

17. The connector according to claim 16, wherein, The first and second cross openings are diametrically opposite each other about the longitudinal axis, such that the central axes of the first and second cross openings are parallel.

18. The connector according to claim 15, wherein, At the axial position of the cross-hole, 20% to 40% of the outer peripheral surface is spaced from the longitudinal axis by a distance greater than a first distance, and the remaining portion of the outer peripheral surface is spaced from the longitudinal axis by a distance not exceeding the first distance, so that the drilling fluid can flow freely over the convex corner in the axial direction.

19. The connector according to claim 15, wherein, At the axial position of the cross-hole, one-third of the outer peripheral surface is spaced from the longitudinal axis by a distance greater than a first distance, and the remaining two-thirds of the outer peripheral surface is spaced from the longitudinal axis by a distance not exceeding the first distance, so that the drilling fluid can flow freely over the convex corner in the axial direction.

20. The connector according to claim 15, wherein, The non-circular profile has a first portion defining a minimum distance from the longitudinal axis and a second portion defining a maximum distance from the longitudinal axis, wherein the radially innermost portion of the cross opening is spaced from the longitudinal axis at a distance equal to or greater than the minimum distance and less than the maximum distance.

21. The connector according to claim 15, wherein, The non-circular profile includes four or more planes distributed in a uniform pattern around the longitudinal axis, each plane including a first pair of adjacent planes defining a vertex therebetween, and wherein the radially innermost portion of the intersecting aperture extends perpendicularly to a reference line extending from the longitudinal axis to the vertex.

22. The connector according to claim 15, wherein, The non-circular profile includes six planes of equal length configured to receive a hexagonal drill pipe.

23. The connector according to claim 15, wherein, The main body is provided with an enlarged portion at an axial position spaced apart from the axial position of the cross orifice, the enlarged portion having one or more fluid flow openings formed to extend between the inner hole and the outer peripheral surface.

24. The connector according to claim 15, wherein, Except for the axial position of the cross opening, the outer peripheral surface of the main body is cylindrical.

25. A connection system for a twin-rod drilling system, the connection system comprising: The connector of claim 15; Internal drill pipe, including: A torque transmission section having a non-circular outer contour, the torque transmission section being configured to mate with the non-circular contour of the connector's inner bore; and The notch formed in the non-circular outer contour; and A pin, which is positioned within the cross-hole of the connector and at least partially within the notch of the inner drill rod, secures the inner drill rod relative to the connector in the direction of the longitudinal axis.

26. The connection system according to claim 25, wherein, The notch is a notch that extends only through the corner formed between a pair of adjacent surfaces of the non-circular outer contour.

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