Bridge plug setting mechanism

Abstract

The present application relates to unconventional oil and gas reservoir completion engineering technical field, especially a kind of bridge plug setting mechanism, to solve the problem of early setting of bridge plug in the process of downhole operation.The present application includes bridge plug, and the bridge plug includes upper cone, lower cone and slip;Upper cone and lower cone are respectively arranged on the upper and lower sides of slip, and are configured to move relatively to extrude slip.Upper cone and lower cone are configured to move down synchronously in the process of bridge plug setting mechanism downhole.As the bridge plug setting mechanism provided by the present application moves down synchronously in the process of downhole operation, the slip will not be extruded and expanded when bumping, resistance and other situations occur, which can prevent the bridge plug from anchoring on the casing and setting early, and prevent the construction risk caused by missetting.

Description

Technical Field

[0001] This invention relates to the field of unconventional oil and gas reservoir completion engineering technology, and in particular to a bridge plug setting mechanism. Background Technology

[0002] Bridge plugs, as sealing tools for oil and gas wells, are characterized by fewer construction steps, shorter cycles, and accurate sealing positions. Currently, high-volume in-casing construction has become a technological trend in the development of tight oil and gas reservoirs, shale oil, and shale gas. However, bridge plugs used in high-volume in-casing construction can only achieve the function of setting the bridge plug; they cannot prevent premature setting, leading to mis-setting during the bridge plug installation process and increasing construction risks. Summary of the Invention

[0003] The purpose of this invention is to provide a bridge plug setting mechanism to solve the problem of premature setting of the bridge plug during the insertion process.

[0004] To solve the above-mentioned technical problems, the technical solution provided by the present invention is as follows:

[0005] A bridge plug setting mechanism includes a bridge plug. The bridge plug includes an upper cone, a lower cone, and a slip; the upper cone and the lower cone are respectively disposed on the upper and lower sides of the slip and configured to move relative to each other to compress the slip; the upper cone and the lower cone are configured to move down synchronously during the lowering process of the bridge plug setting mechanism.

[0006] Furthermore, the bridge plug setting mechanism also includes a bridge plug setting connector package, which includes a split claw pusher and a split claw retaining sleeve; the split claw pusher and the split claw retaining sleeve are coaxially arranged, the split claw pusher is connected to the upper cone, and the split claw retaining sleeve is connected to the lower cone; the split claw pusher and the split claw retaining sleeve are configured to move down synchronously during the lowering process of the bridge plug setting mechanism.

[0007] Furthermore, the bridge plug setting connector package also includes a core rod; a split claw pusher sleeve is fitted onto the upper part of the core rod and is slidably connected to the core rod; and a split claw retaining sleeve is fitted onto the lower part of the core rod and is connected to the core rod.

[0008] Furthermore, the bridge plug also includes a pressure cap, which is fitted onto the lower part of the core rod, with the upper end of the pressure cap abutting against the lower end of the split claw-type retaining sleeve.

[0009] Furthermore, the bridge plug also includes a shear pin, which is inserted into the core rod after passing through the side wall of the pressure cap.

[0010] Furthermore, the lower side of the split claw pusher is inserted into the upper cone; the lower end of the split claw pusher is provided with a protruding first locking block, and the inner wall of the upper cone is provided with a first groove, the first locking block and the first groove cooperating.

[0011] Furthermore, the split claw-type fixing sleeve is inserted into the lower cone; the lower end of the split claw-type fixing sleeve is provided with a protruding second locking block, and the inner wall of the connection between the lower cone and the lower pressure cap forms a second groove, and the second locking block cooperates with the second groove.

[0012] Furthermore, the core rod is provided with a first reduced diameter section and a second reduced diameter section; after the split claw pusher moves down relative to the core rod, the first locking block is located in the first reduced diameter section and can be disengaged from the first groove; after the core rod is lifted up, the second locking block is located in the second reduced diameter section and can be disengaged from the second groove.

[0013] Furthermore, the bridge plug setting connector package also includes a C-shaped ring snapped onto the core rod; the C-shaped ring is disposed within the annular space formed by the core rod and the segmented claw retaining sleeve; after the core rod moves upward, the upper end face of the C-shaped ring abuts against the segmented claw retaining sleeve.

[0014] Furthermore, the bridge plug setting connector package also includes a connecting sleeve, the lower side of which is fitted onto the upper side of the split claw pusher, and the connecting sleeve is screwed to the split claw pusher.

[0015] In summary, the technical effects achieved by this invention are as follows:

[0016] This invention provides a bridge plug setting mechanism, comprising a bridge plug. The bridge plug includes an upper cone, a lower cone, and a slip; the upper cone and the lower cone are respectively disposed on the upper and lower sides of the slip, configured to move relative to each other to compress the slip. The upper cone and the lower cone are configured to move downward synchronously during the lowering process of the bridge plug setting mechanism.

[0017] Because the bridge plug setting mechanism provided by this invention moves the upper and lower cones synchronously during the lowering process, it will not squeeze the slips and cause them to expand when there is a collision or obstruction. This allows the bridge plug to be anchored on the casing in advance and set, preventing construction risks caused by mis-setting. Attached Figure Description

[0018] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a cross-sectional view of the bridge plug setting mechanism provided in an embodiment of the present invention;

[0020] Figure 2 for Figure 1 Cross-sectional view of the bridge plug setting joint package;

[0021] Figure 3 for Figure 2 Schematic diagram of the split claw-type fixing sleeve;

[0022] Figure 4 for Figure 1 Cross-sectional view of the bridge plug;

[0023] Figure 5 for Figure 4 Cross-sectional view of the C-shaped central tube;

[0024] Figure 6 A cross-sectional view showing the setting of the bridge plug setting mechanism provided in an embodiment of the present invention;

[0025] Figure 7 A cross-sectional view showing the release mechanism of the bridge plug setting mechanism provided in an embodiment of the present invention;

[0026] Figure 8 A cross-sectional view of the bridge plug setter assembly after it has been discarded.

[0027] Icons: 100-Bridge plug; 200-Bridge plug setting connector; 110-Upper cone; 120-Lower cone; 130-Slipper; 140-Lower pressure cap; 150-Shear pin; 160-Sealing mechanism; 170-C-shaped center tube; 180-Slipper pellet; 210-Split claw pusher; 220-Split claw fixing sleeve; 230-Core rod; 240-C-ring; 250-Connecting sleeve; 111-First groove; 121-Second groove; 211-First locking block; 212-Pusher pressure ring; 213-Pusher split claw; 221-Second locking block; 222-Fixing sleeve ring; 223-Fixing sleeve split claw; 231-First diameter reduction section; 232-Second diameter reduction section; 233-Ring boss. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0029] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0030] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0031] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0032] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0033] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0034] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0035] The bridge plug used in high-volume casing construction can only achieve the function of setting the bridge plug, but cannot prevent the bridge plug from setting prematurely, which leads to the problem of accidental setting during the lowering of the bridge plug, increasing the construction risk.

[0036] In view of this, the present invention provides a bridge plug setting mechanism, including a bridge plug 100. The bridge plug 100 includes an upper cone 110, a lower cone 120, and a slip 130; the upper cone 110 and the lower cone 120 are respectively disposed on the upper and lower sides of the slip 130, configured to move relative to each other to compress the slip 130. The upper cone 110 and the lower cone 120 are configured to move downward synchronously during the lowering process of the bridge plug setting mechanism.

[0037] Because the bridge plug setting mechanism provided by this invention moves the upper cone 110 and the lower cone 120 synchronously downwards during the lowering process, it will not squeeze the slip 130 and cause the slip 130 to expand when there is a collision or obstruction, so that the bridge plug 100 is anchored on the casing in advance and set, thus preventing the construction risks caused by mis-setting.

[0038] The following combination Figures 1-8 The structure and shape of the bridge plug setting mechanism provided in this embodiment are described in detail below:

[0039] In an optional embodiment, the bridge plug setting mechanism further includes a bridge plug setting connector package 200, which includes a split claw pusher 210 and a split claw fixing sleeve 220. For example... Figure 1 , Figure 2 As shown, the split claw pusher 210 and the split claw fixing sleeve 220 are coaxially arranged. The split claw pusher 210 is connected to the upper cone 110, and the split claw fixing sleeve 220 is connected to the lower cone 120. The split claw pusher 210 and the split claw fixing sleeve 220 are configured to move down synchronously during the lowering process of the bridge plug setting mechanism, so as to avoid premature setting of the bridge plug 100 due to collisions, obstructions, or other reasons during the lowering process.

[0040] Furthermore, such as Figure 1 , Figure 2 , Figure 4 As shown, the split claw pusher 210 includes a first locking block 211, a pusher pressure ring 212, and a pusher split claw 213. The upper end of the pusher split claw 213 is connected to the pusher pressure ring 212, and the lower end of the pusher split claw 213 is connected to the first locking block 211. The lower side of the pusher pressure ring 212 abuts against the upper end face of the upper cone 110. The inner wall of the upper cone 110 is provided with a first groove 111. The first locking block 211 engages with the first groove 111, thereby connecting the split claw pusher 210 to the upper cone 110. Similarly, as... Figure 2 , Figure 3 As shown, the split claw type fixing sleeve 220 includes a second locking block 221, a fixing sleeve ring 222, and a fixing sleeve split claw 223. The upper end of the fixing sleeve split claw 223 is connected to the fixing sleeve ring 222, and the lower end of the fixing sleeve split claw 223 is connected to the second locking block 221.

[0041] In this embodiment, the bridge plug setting connector package 200 further includes a connecting sleeve 250. The lower side of the connecting sleeve 250 is fitted onto the push cylinder pressure ring 212 and screwed to the push cylinder pressure ring 212. The upper part of the connecting sleeve 250 is provided with an internal thread for connecting with the setting tool.

[0042] In this embodiment, the bridge plug setting connector package 200 also includes a core rod 230. For example... Figure 2As shown, the split claw-type pusher 210 is fitted onto the upper part of the core rod 230 and is slidably connected to the core rod 230; the split claw-type fixing sleeve 220 is fitted onto the lower part of the core rod 230 and is connected to the core rod 230. Specifically, a circular boss 233 is provided in the middle of the core rod 230, and the upper end of the fixing sleeve circular boss 222 abuts against the lower end of the circular boss 233; the upper end of the core rod 230 is provided with an external thread for connection with the setting tool.

[0043] In this embodiment, the bridge plug 100 also includes a pressure cap 140. For example... Figure 1 , Figure 4 As shown, the lower pressure cap 140 is fitted onto the lower part of the core rod 230, and the upper end of the lower pressure cap 140 abuts against the lower end of the split claw type fixing sleeve 220. The lower pressure cap 140 and the annular boss 233 hold the split claw type fixing sleeve 220 in place, thus fixing the split claw type fixing sleeve 220 onto the core rod 230.

[0044] Specifically, the bridge plug 100 also includes a shear pin 150, which passes through the side wall of the pressure cap 140 and is inserted into the core rod 230, so that the core rod 230 is connected to the pressure cap 140.

[0045] Furthermore, the lower pressure cap 140 is inserted into the lower part of the lower cone 120 and threadedly connected to the lower cone 120. Specifically, as... Figure 4 As shown, the upper end face of the lower pressure cap 140 mates with the boss on the inner wall of the lower cone 120 to form a second groove 121; as Figure 1 As shown, the second locking block 221 engages with the second groove 121, thereby connecting the split claw-type fixing sleeve 220 with the lower cone 120.

[0046] In this embodiment, the core rod 230 is provided with a first diameter reduction section 231 and a second diameter reduction section 232, such as Figure 2 As shown. After the split claw pusher 210 moves downward relative to the core rod 230, the first locking block 211 is located in the first reduced diameter section 231. At this time, the split claw 213 of the pusher loses the support of the core rod 230, and the first locking block 211 can be disengaged from the first groove 111. After the core rod 230 is lifted, the second locking block 221 is located in the second reduced diameter section 232. At this time, the split claw 223 of the fixing sleeve loses the support of the core rod 230, and the second locking block 221 can be disengaged from the second groove 121. Furthermore, both the upper and lower ends of the first locking block 211 and the second locking block 221 are chamfered to prevent the first locking block 211 and the second locking block 221 from getting stuck in the first groove 111 and the second groove 121 respectively, thus preventing them from disengaging.

[0047] In this embodiment, the bridge plug setting connector package 200 further includes a C-shaped ring 240 that is snapped onto the core rod 230. The C-shaped ring 240 is disposed within the annular space formed by the core rod 230 and the segmented claw-type fixing sleeve 220; after the core rod 230 moves upward, the upper end face of the C-shaped ring 240 abuts against the segmented claw-type fixing sleeve 220, causing the segmented claw-type fixing sleeve 220 to move upward together with the core rod 230.

[0048] In this embodiment, as Figure 4 As shown, the bridge plug 100 also includes a slip 180, which is embedded in the slip 130. During setting, the slip 180 engages with the inner wall of the sleeve, improving the stability of the setting.

[0049] In this embodiment, the bridge plug 100 further includes a sealing mechanism 160, which is fitted onto the lower part of the upper cone 110, with the lower end of the sealing mechanism 160 abutting against the upper end of the slip 130. During setting, the upper cone 110 moves downward, compressing the sealing mechanism 160 and the slip 130, causing the sealing mechanism 160 to expand and abut against the inner wall of the sleeve, thus achieving interlayer sealing.

[0050] In this embodiment, the bridge plug 100 also includes a C-shaped central tube 170, such as Figure 4 , Figure 5 As shown, the outer side of the C-shaped central tube 170 is provided with reverse-toothed threads, and the reverse-toothed threads on the upper and lower sides are in opposite directions. The inner wall of the upper cone 110 is provided with reverse-toothed threads corresponding to the reverse-toothed threads on the upper side of the C-shaped central tube 170; the inner wall of the lower cone 120 is provided with reverse-toothed threads corresponding to the reverse-toothed threads on the lower side of the C-shaped central tube 170. After setting, the reverse-toothed threads on the upper cone 110 and the lower cone 120 respectively engage with the reverse-toothed threads on the C-shaped central tube 170, preventing the upper cone 110 and the lower cone 120 from moving away from each other, thereby causing the slip 130 to retract and resulting in unsealing.

[0051] Specifically, the C-shaped central tube 170 has a C-shaped cross-section, meaning it has an open sidewall. When the upper cone 110 and lower cone 120 mate with the C-shaped central tube 170, the C-shaped central tube 170 is compressed by the upper cone 110 and lower cone 120, reducing its outer diameter and facilitating the fit. After mating, the C-shaped central tube 170 returns to its original shape under its own elasticity and abuts against the inner walls of the upper cone 110 and lower cone 120. The reverse-toothed thread prevents the upper cone 110 and lower cone 120 from moving away from each other.

[0052] The working process of the bridge plug setting mechanism provided in this embodiment is as follows:

[0053] Before using the bridge plug setting mechanism, the bridge plug 100 and the bridge plug setting connector package 200 must first be assembled. First, connect the connecting sleeve 250 to the setting tool, and install the C-ring 240 and the split claw type fixing sleeve 220 on the core rod 230; then connect the split claw type pusher 210 to the connecting sleeve 250, and then install the upper cone 110, C-shaped center tube 170, sealing mechanism 160, slip 130 and slip pellet 180 in sequence; then connect the core rod 230 to the setting tool, so that the core rod 230, C-ring 240 and split claw type fixing sleeve 220 are inserted into the bridge plug 100; finally, fit the lower cone 120 onto the split claw type fixing sleeve 220, then connect the lower pressure cap 140 to the lower cone 120 and install the shear pin 150.

[0054] Since both the core rod 230 and the connecting sleeve 250 are connected to the setting tool, they can remain relatively fixed during the lowering process to achieve synchronous lowering. This allows the split claw pusher 210 and the split claw fixing sleeve 220 to also move synchronously during the lowering process. Due to the cooperation between the first locking block 211 and the first groove 111, as well as the cooperation between the second locking block 221 and the second groove 121, the split claw pusher 210 is connected to the upper cone 110, and the split claw fixing sleeve 220 is connected to the lower cone 120. Ultimately, the upper cone 110 and the lower cone 120 move synchronously, maintaining their relative positions during the lowering process. This prevents the relative movement of the upper cone 110 and the lower cone 120 due to bumps, obstructions, or other reasons, which could lead to premature setting.

[0055] After the tool is lowered into place, power on the tool to start the setting process. For example... Figure 6 As shown, the setting tool pushes the connecting sleeve 250 downwards, which in turn drives the split claw pusher 210 and the upper cone 110 downwards. At this time, the lower cone 120 is locked by the core rod 230 and remains stationary. Then, under the compression of the upper cone 110 and the lower cone 120, the sealing mechanism 160 and the slip 130 expand. Finally, the sealing mechanism 160 abuts against the inner wall of the casing, achieving interlayer sealing. At the same time, after the slip 130 expands, it drives the slip piece 180 to press against the inner wall of the casing, completing the anchoring on the casing, and finally achieving setting. During the setting process, the step on the inner wall of the upper cone 110 abuts against the upper end face of the C-shaped central tube 170 and drives the C-shaped central tube 170 downwards, so that the reverse toothed thread on the C-shaped central tube 170 engages with the reverse toothed thread on the inner wall of the upper cone 110 and the lower cone 120, respectively.

[0056] After the setting is completed, activate the setting tool and lift the core rod 230, as follows. Figure 7As shown, the shear pin 150 is cut first, and then the core rod 230 continues to move upward. At this point, because the second locking block 221 is engaged in the second groove 121, the second locking block 221 remains stationary. As the core rod 230 moves upward, the second locking block 221 falls into the second reduced-diameter section 232. Simultaneously, because the split claw-type fixing sleeve 220 remains stationary with the connecting sleeve 250, as the core rod 230 moves upward, the first locking block 211 falls into the first reduced-diameter section 231.

[0057] Finally, the setting tool simultaneously lifts the connecting sleeve 250 and the core rod 230. The connecting sleeve 250 drives the split claw pusher 210 upward, and the first locking block 211 disengages from the first groove 111. Simultaneously, as the core rod 230 moves upward, the C-ring 240 and the split claw fixing sleeve 220 abut against each other and drive the split claw fixing sleeve 220 upward, causing the second locking block 221 to disengage from the second groove 121. Ultimately, the setting tool causes the bridge plug setting connector package 200 to completely disengage from the bridge plug 100, achieving release. Figure 8 Package 200 for the bridge plug seat joint after it has been discarded.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A bridge plug setting mechanism, characterized in that, Includes a bridge plug (100), which includes an upper cone (110), a lower cone (120), and a slip (130). The upper cone (110) and the lower cone (120) are respectively disposed on the upper and lower sides of the slip (130) and configured to move relative to each other to squeeze the slip (130). The upper cone (110) and the lower cone (120) are configured to move down synchronously during the insertion of the bridge plug setting mechanism; The bridge plug (100) also includes a C-shaped central tube (170), the outer side of which is provided with a reverse tooth thread, and the reverse tooth threads on the upper and lower sides are in opposite directions; the inner wall of the upper cone (110) is provided with a reverse tooth thread corresponding to the reverse tooth thread on the upper side of the C-shaped central tube (170); the inner wall of the lower cone (120) is provided with a reverse tooth thread corresponding to the reverse tooth thread on the lower side of the C-shaped central tube (170); It also includes a bridge plug setting connector package (200), which includes a split claw pusher (210) and a split claw retaining sleeve (220). The split claw pusher (210) and the split claw fixing sleeve (220) are coaxially arranged. The split claw pusher (210) is connected to the upper cone (110), and the split claw fixing sleeve (220) is connected to the lower cone (120). The split claw pusher (210) and the split claw fixing sleeve (220) are configured to move down synchronously during the insertion of the bridge plug setting mechanism; The bridge plug setting connector package (200) also includes a core rod (230). The split claw-type pusher (210) is fitted onto the upper part of the core rod (230) and is slidably connected to the core rod (230); The split claw-type fixing sleeve (220) is fitted onto the lower part of the core rod (230) and connected to the core rod (230); The bridge plug (100) also includes a lower pressure cap (140). The lower side of the split claw-type pusher (210) is inserted into the upper cone (110). The lower end of the split claw-type pusher (210) is provided with a protruding first locking block (211), and the inner wall of the upper cone (110) is provided with a first groove (111), and the first locking block (211) cooperates with the first groove (111). The split claw-type fixing sleeve (220) is inserted into the lower cone (120); The lower end of the split claw-type fixing sleeve (220) is provided with a protruding second locking block (221), and the inner wall of the connection between the lower cone (120) and the lower pressure cap (140) forms a second groove (121), and the second locking block (221) cooperates with the second groove (121); The core rod (230) is provided with a first reduced diameter section (231) and a second reduced diameter section (232). After the split claw-type pusher (210) moves down relative to the core rod (230), the first locking block (211) is located in the first reduced diameter section (231), and the first locking block (211) can be dislodged from the first groove (111); After the core rod (230) is lifted, the second locking block (221) is located in the second reduced diameter section (232), and the second locking block (221) disengages from the second groove (121); The bridge plug setting connector package (200) also includes a C-ring (240) that snaps into the core rod (230). The C-shaped ring (240) is disposed within the annular space formed by the core rod (230) and the segmented claw-type fixing sleeve (220); After the core rod (230) moves upward, the upper end face of the C-shaped ring (240) abuts against the split claw-type fixing sleeve (220).

2. The bridge plug setting mechanism according to claim 1, characterized in that, The pressure cap (140) is fitted onto the lower part of the core rod (230), and the upper end of the pressure cap (140) abuts against the lower end of the split claw-type fixing sleeve (220).

3. The bridge plug setting mechanism according to claim 2, characterized in that, The bridge plug (100) also includes a shear pin (150) that is inserted into the core rod (230) after passing through the side wall of the pressure cap (140).

4. The bridge plug setting mechanism according to claim 3, characterized in that... The bridge plug setting connector package (200) also includes a connecting sleeve (250), the lower side of which is fitted onto the upper side of the split claw pusher (210), and the connecting sleeve (250) is screwed to the split claw pusher (210).

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