Marine work lifting hook box steel pipe limiting device

Abstract

The invention relates to the technical field of marine hoisting equipment, and discloses a marine lifting hook box steel pipe limiting device which comprises a main body, the main body comprises a limiting sleeve and a mounting seat, the mounting seat is mounted on a fixed structure body, the limiting sleeve is arranged on the mounting seat, a pipe passing hole is formed in the limiting sleeve, and a steel pipe can penetrate through the pipe passing hole; the limiting assembly comprises a limiting part and a locking piece, the limiting part is rotationally arranged on the limiting sleeve, the limiting part is used for abutting against the steel pipe penetrating through the pipe passing hole, the locking piece is connected with the other end of the limiting part, the locking piece is movably arranged on the mounting base, and a locking position and an unlocking position are arranged in the moving range of the locking piece; when the locking piece is located at the locking position, the limiting part can abut against the steel pipe. When the locking piece is located at the unlocking position, the limiting part does not abut against the steel pipe. According to the maritime work carving steel pipe limiting device, the steel pipe penetrating through the maritime work lifting hook box steel pipe limiting device can be prevented from deviating or rotating, and the transportation stability is guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of marine hoisting equipment, in particular to a steel pipe limiting device for a marine engineering hook box. Background Art

[0002] In the construction process of marine engineering, the hook box is a key component of the lifting system, and its stability and safety are crucial to the smooth progress of the project. Especially in harsh marine environments, the limit device of the hook box must have strong wind and wave resistance and precise positioning capabilities to ensure the safety and efficiency of the lifting operation.

[0003] However, the existing hook box limiter often faces the problems of complex structure, inconvenient maintenance and insufficient positioning accuracy. The fixing and positioning device of the steel frame steel pipe is relatively simple, which is difficult to effectively prevent the steel pipe from deflecting or rotating, thereby affecting the stability of transportation. Summary of the invention

[0004] The purpose of the present invention is to provide a steel pipe limiting device for an offshore engineering hook, which can prevent the steel pipe passing through the steel pipe limiting device of the offshore engineering hook box from deflecting or rotating, thereby ensuring the stability of transportation.

[0005] In order to achieve the above object, the present invention provides a steel pipe limiting device for a marine engineering hook box, comprising:

[0006] A main body, the main body comprising a limiting sleeve and a mounting seat, the mounting seat being mounted on a fixed structure, the limiting sleeve being arranged on the mounting seat, the limiting sleeve being provided with a pipe-passing hole along its radial direction, the pipe-passing hole being used for allowing a steel pipe to pass through;

[0007] A limit assembly, the limit assembly includes a limit part and a locking piece, the limit part is rotatably arranged on the limit sleeve, one end of the limit part is used to abut the steel pipe passing through the tube hole, the locking piece is connected to the other end of the limit part, the locking piece is movably arranged on the mounting seat, and has a locking position and an unlocking position within the movable range of the locking piece, when the locking piece is located at the locking position, one end of the limit part can abut against the steel pipe passing through the tube hole; when the locking piece is located at the unlocking position, one end of the limit part does not abut against the steel pipe passing through the tube hole.

[0008] Further, the limiting sleeve extends in the up-down direction, one end of the limiting sleeve is connected to the mounting seat, the limiting sleeve is provided with a clearance hole along its radial direction, a hinge portion is provided on the outer wall of the limiting sleeve, the hinge portion is located below the clearance hole, the limiting portion includes a first swing arm and a second swing arm, the middle part of the first swing arm is hinged in the clearance hole, the middle part of the second swing arm is hinged on the hinge portion, the upper end of the second swing arm is abutted against the lower end of the first swing arm, and the locking piece includes a locking bolt, the locking bolt passes through the lower end of the second swing arm, the limiting sleeve and is screwed to the mounting seat in sequence along the radial direction of the limiting sleeve.

[0009] Furthermore, the first swing arm includes a contact arm body and a counterweight arm body, one end of the contact arm body is connected to one end of the counterweight arm body, the contact arm body and the counterweight arm body are arranged at an angle, and the angle between the contact arm body and the counterweight arm body is 110° to 130°.

[0010] Furthermore, the hinged joint between the first swing arm and the clearance hole is located on the abutting arm body, and the hinged joint between the first swing arm and the clearance hole is arranged close to the connection between the abutting arm body and the counterweight arm body.

[0011] Furthermore, the offshore engineering hook box steel pipe limiting device includes at least two limiting components, and the limiting sleeve is centrally symmetrically provided with at least two making way holes in the circumferential direction, and the making way holes are hinged to the first swing arm in a one-to-one correspondence.

[0012] Furthermore, the mounting seat includes an embedded part, a seat body and a mounting bolt, one end of the limiting sleeve is arranged on the seat body, the embedded part is embedded in the fixed structure, a mounting hole is opened on the embedded part, the mounting hole has an internal thread, the mounting bolt passes through the seat body and engages with the mounting hole to install the seat body on the embedded part.

[0013] Furthermore, the mounting seat also includes a mounting block, the seat body is provided with a mounting groove, part of the mounting block is shaped to be embedded in the mounting groove, and the remaining part protrudes from the mounting groove, and a plurality of adjustment holes are provided on the outer peripheral wall of the mounting block protruding from the mounting groove, the adjustment holes correspond one-to-one with the limit components, the adjustment holes have internal threads, the locking bolts are engaged with the adjustment holes, and the mounting bolts extend in the up and down directions in sequence through the mounting block and the seat body and are engaged with the mounting holes.

[0014] Furthermore, the upper end surface of the mounting bolt is tangent to the lower end of the pipe hole, and a cushion layer is provided on the upper end surface of the mounting bolt.

[0015] Compared with the prior art, the steel pipe limiting device for a marine engineering hook according to the embodiment of the present invention has the following beneficial effects: when the locking piece is in the unlocking position, it can pass through the pipe passing hole of the limiting sleeve, and after passing through, the locking piece is switched to the locking position, the limiting portion abuts against the steel pipe, and applies a certain pressure to the steel pipe, thereby preventing the steel pipe from sliding in the pipe passing hole, and completing the locking and limiting of the steel pipe; a plurality of marine engineering hook box steel pipe limiting devices are arranged on the same straight line, and the extension directions of the pipe passing holes of the marine engineering hook box steel pipe limiting devices are consistent, and the steel pipe passing through the marine engineering hook box steel pipe limiting device is radially limited, and each limiting portion can apply force to the steel pipe in sections, abut against the steel pipe, and limit the axial sliding of the steel pipe, and perform all-round locking and limiting, which can effectively prevent the steel pipe from deflecting or rotating, and ensure the stability of transportation. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 2. It is a structural cross-sectional view of a steel pipe limiting device for a marine engineering hook according to an embodiment of the present invention;

[0017] Figure 2 yes Figure 1 Partial cross-sectional view at point A.

[0018] In the figure, 1, main body; 101, limiting sleeve; 1011, pipe hole; 1012, clearance hole; 103, hinged part; 102, mounting seat; 1021, embedded part; 10211, mounting hole; 1022, seat body; 10221, mounting groove; 1023, mounting bolt; 10231, cushion layer; 1024, mounting block; 10241, adjustment hole;

[0019] 2. Limiting assembly; 201. Limiting part; 2011. First swing arm; 20111. Abutting arm body; 20112. Counterweight arm body; 2012. Second swing arm; 20121. Extension section; 202. Locking member; 2021. Locking bolt;

[0020] 3. Fixed structure. DETAILED DESCRIPTION

[0021] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0022] In the description of the present invention, the terms "upper", "lower", "left", "right", "front", "rear", "inner", "outer", "lateral", "longitudinal" and the like used to indicate the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only used to facilitate the description of the present invention and simplify the description, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. For those of ordinary skill in the art, the specific meanings of these terms in the present invention can be understood according to specific circumstances.

[0023] In the description of the present invention, the terms "provided with", "set", "connected", and "placed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, elements, or components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0024] In addition, the terms "first", "second", etc. are mainly used to distinguish different devices, elements or components (the specific types and structures may be the same or different), and are not used to indicate or imply the relative importance and quantity of the indicated devices, elements or components. Unless otherwise specified, "plurality" means two or more.

[0025] The technical solution of the present invention is further described below in conjunction with embodiments and drawings.

[0026] like Figure 1 , 2 As shown, a steel pipe limiting device for a marine hook box according to an embodiment of the present invention comprises:

[0027] The main body 1 includes a limiting sleeve 101 and a mounting seat 102. The mounting seat 102 is mounted on the fixed structure 3. The limiting sleeve 101 is arranged on the mounting seat 102. The limiting sleeve 101 is provided with a pipe-passing hole 1011 along its radial direction. The pipe-passing hole 1011 is used for the steel pipe to pass through.

[0028] The limiting component 2 includes a limiting portion 201 and a locking member 202. The limiting portion 201 is rotatably arranged on the limiting sleeve 101. One end of the limiting portion 201 is used to abut the steel pipe passing through the tube hole 1011. The locking member 202 is connected to the other end of the limiting portion 201. The locking member 202 is movably arranged on the mounting seat 102. The locking member 202 has a locking position and an unlocking position within the movable range. When the locking member 202 is located at the locking position, one end of the limiting portion 201 can abut against the steel pipe passing through the tube hole 1011; when the locking member 202 is located at the unlocking position, one end of the limiting portion 201 does not abut against the steel pipe passing through the tube hole 1011.

[0029] Based on the above technical solution, when the locking member 202 is in the unlocking position, it can pass through the pipe hole 1011 of the limiting sleeve 101. After passing through, the locking member 202 is switched to the locking position, and the limiting portion 201 abuts against the steel pipe and applies a certain pressure to the steel pipe to prevent the steel pipe from sliding in the pipe hole 1011, thereby completing the locking and limiting of the steel pipe; multiple offshore engineering hook box steel pipe limiting devices are arranged on the same straight line, and the extension directions of the pipe holes 1011 of each offshore engineering hook box steel pipe limiting device are consistent, and the steel pipe passing through the offshore engineering hook box steel pipe limiting device is radially limited, and each limiting portion 201 can apply force to the steel pipe in sections, limit the axial sliding of the steel pipe, and perform all-round locking and limiting, which can effectively prevent the steel pipe from deflecting or rotating, and ensure the stability of transportation.

[0030] Preferably, the limiting sleeve 101 extends in the up-down direction, one end of the limiting sleeve 101 is connected to the mounting seat 102, the limiting sleeve 101 is provided with a clearance hole 1012 along its radial direction, a hinged portion 103 is provided on the outer wall of the limiting sleeve 101, the hinged portion 103 is located below the clearance hole 1012, the limiting portion 201 includes a first swing arm 2011 and a second swing arm 2012, the middle part of the first swing arm 2011 is hinged in the clearance hole 1012, the middle part of the second swing arm 2012 is hinged on the hinged portion 103, the upper end of the second swing arm 2012 is abutted against the lower end of the first swing arm 2011, the locking member 202 includes a locking bolt 2021, the locking bolt 2021 passes through the lower end of the second swing arm 2012, the limiting sleeve 101 in sequence along the radial direction of the limiting sleeve 101 and is screwed to the mounting seat 102.

[0031] Based on the above technical solution, when the locking member 202 switches from the unlocking position to the locking position, the locking bolt 2021 is gradually screwed into the mounting seat 102, and the second swing arm 2012 rotates around the hinge portion 103. The lower end of the second swing arm 2012 is close to the limiting sleeve 101, and the upper end of the second swing arm 2012 is away from the limiting sleeve 101. The upper end of the second swing arm 2012 pushes the first swing arm 2011 to rotate, and the lower end of the first swing arm 2011 is pushed away from the limiting sleeve 101 by the upper end of the second swing arm 2012. The upper end of the first swing arm 2011 can abut against the steel pipe passing through the pipe hole 1011. At this time, the locking bolt 2021 continues to be screwed into the mounting seat 102, and the upper end of the first swing arm 2011 can be applied to the steel pipe passing through the pipe hole 1011 is used to lock the steel pipe pressure; when the locking member 202 is switched from the locking position to the unlocking position, the locking bolt 2021 is gradually screwed out of the mounting seat 102, however, it is known that the bolt will not fall out of the mounting seat 102, and the second swing arm 2012 rotates around the hinge 103, and the lower end of the second swing arm 2012 is away from the limiting sleeve 101, and the upper end of the second swing arm 2012 is close to the limiting sleeve 101, and the thrust of the upper end of the second swing arm 2012 on the first swing arm 2011 is gradually reduced until the upper end of the second swing arm 2012 is no longer in contact with the lower end of the first swing arm 2011, and the upper end of the first swing arm 2011 releases the force on the steel pipe. At this time, the locking fails and the steel pipe can slide along the pipe hole 1011.

[0032] More preferably, the first swing arm 2011 includes a butt arm body 20111 and a counterweight arm body 20112, one end of the butt arm body 20111 is connected to one end of the counterweight arm body 20112, the butt arm body 20111 and the counterweight arm body 20112 are arranged at an angle, and the angle between the butt arm body 20111 and the counterweight arm body 20112 is 110° to 130°. The counterweight arm 20112 is provided to ensure that when the steel pipe is not inserted into the through-tube hole 1011, the lower end of the first swing arm 2011 is always in contact with the upper end of the second swing arm 2012 due to the gravity of the counterweight arm 20112, so as to avoid the abutment arm 20111 rotating to the through-tube hole 1011 when the steel bar passes through the through-tube hole 1011, and the staff need to adjust the abutment arm 20111 and then pass the steel pipe through the through-tube hole 1011; the angle between the abutment arm 20111 and the counterweight arm 20112 is preferably If the angle is greater than 130°, the required rotation path of the second swing arm 2012 is too long, which is not conducive to the compact design of the steel pipe limiting device for the offshore engineering hook box.

[0033] In a specific embodiment, the lower end of the second swing arm 2012 has an extension section 20121, and the extension direction of the extension section 20121 is consistent with the extension direction of the second swing arm 2012. The locking bolt 2021 passes through the extension section 20121 and the limiting sleeve 101 in sequence and is screwed with the mounting seat 102. In the first swing arm 2011, the length of the counterweight arm body 20112 is greater than the abutting arm body 20111. Through the lever principle, the long displacement of the screw connection of the locking bolt 2021 is converted into the pressure of the abutting arm body 20111 on the steel pipe. Even if the locking bolt 2021 has a small range of position floating, the pressure on the steel pipe can still be maintained. Moreover, since the locking bolt 2021 is screwed with the mounting seat 102, it is difficult for the locking member 202 to switch from the locked position to the unlocked position without human intervention. Even if an emergency occurs, the locking bolt 2021 will not be instantly screwed out with a large stroke, thereby maintaining the locking limit on the steel pipe.

[0034] More preferably, the hinge of the first swing arm 2011 and the clearance hole 1012 is located on the abutting arm body 20111, and the hinge of the first swing arm 2011 and the clearance hole 1012 is arranged close to the connection between the abutting arm body 20111 and the counterweight arm body 20112. The connection between the abutting arm body 20111 and the counterweight arm body 20112 and the hinge of the first arm body and the clearance hole 1012 are arranged in a staggered manner. On the rotation path of the first swing arm 2011, the connection between the abutting arm body 20111 and the counterweight arm body 20112 and the clearance hole 1012 can abut against each other, limiting the rotation range of the first swing arm 2011 and reducing unnecessary rotation positions of the first swing arm 2011, thereby reducing the additional operations of the construction personnel to adjust the equipment.

[0035] More preferably, the steel pipe limiting device of the offshore hook box includes at least two limiting components 2, and the limiting sleeve 101 is provided with at least two clearance holes 1012 symmetrically in the circumferential direction, and the clearance holes 1012 are hingedly connected with the first swing arm 2011 in a one-to-one correspondence. By providing at least two limiting components 2, the single-point abutment of the steel pipe is changed to multi-point abutment, and the force applied to the steel pipe is more uniform, and when the locking member 202 of one of the limiting components 2 fails to lock, the locking members 202 of the remaining limiting components 2 can still maintain the locking function, thereby ensuring the safety of the structure.

[0036] More preferably, the mounting seat 102 includes an embedded part 1021, a seat body 1022 and a mounting bolt 1023, one end of the limiting sleeve 101 is arranged on the seat body 1022, the embedded part 1021 is embedded in the fixed structure 3, the embedded part 1021 is provided with a mounting hole 10211, the mounting hole 10211 has an internal thread, and the mounting bolt 1023 passes through the seat body 1022 and engages with the mounting hole 10211 to mount the seat body 1022 on the embedded part 1021. The embedded part 1021 is arranged on the fixed structure 3, and the seat body 1022 is detachably mounted on the embedded part 1021 by the mounting bolt 1023. If the seat body 1022 and the structure arranged on the seat body 1022 are damaged, they can be replaced in time, and the replacement is convenient and quick.

[0037] More preferably, the mounting seat 102 also includes a mounting block 1024, a mounting groove 10221 is opened on the seat body 1022, part of the mounting block 1024 is shaped to be embedded in the mounting groove 10221, and the remaining part protrudes from the mounting groove 10221, and a plurality of adjustment holes 10241 are opened on the outer peripheral wall of the mounting block 1024 protruding from the mounting groove 10221, and the adjustment holes 10241 correspond one-to-one to the limit assembly 2, and the adjustment hole 10241 has an internal thread, and the locking bolt 2021 is engaged with the adjustment hole 10241, and the mounting bolt 1023 extends in the up and down direction to pass through the mounting block 1024 and the seat body 1022 in sequence and engage with the mounting hole 10211.

[0038] More preferably, the upper end surface of the mounting bolt 1023 is tangent to the lower end of the pipe hole 1011 , and a cushion layer 10231 is provided on the upper end surface of the mounting bolt 1023 .

[0039] When the steel pipe passes through the pipe hole 1011 and the locking piece 202 is in the locking position, the abutting arm 20111 presses the steel pipe onto the cushion layer 10231 on the upper end face of the mounting bolt 1023. The cushion layer 10231 abuts against the steel pipe, and the mounting bolt 1023 is limited by the steel pipe to prevent the mounting bolt 1023 from loosening, thereby ensuring the connection consistency of the embedded part 1021, the seat body 1022, and the mounting block 1024 and the stable structure. The mounting block 1024 can be specifically set according to the mounting bolt 1023 used to ensure that the upper end face of the mounting bolt 1023 is tangent to the lower end of the pipe hole 1011.

[0040] In summary, an embodiment of the present invention provides a steel pipe limiting device for an offshore engineering hook box, and when the locking member 202 is in the unlocking position, it can pass through the pipe hole 1011 of the limiting sleeve 101. After passing through, the locking member 202 is switched to the locking position, and the limiting portion 201 abuts against the steel pipe, and applies a certain pressure to the steel pipe to prevent the steel pipe from sliding in the pipe hole 1011, thereby completing the locking and limiting of the steel pipe; a plurality of offshore engineering hook box steel pipe limiting devices are arranged on the same straight line, and the pipe holes 1011 of each offshore engineering hook box steel pipe limiting device extend in the same direction, and the steel pipe passing through the offshore engineering hook box steel pipe limiting device is radially limited, and each limiting portion 201 can apply force to the steel pipe in sections, abut the steel pipe, and limit the axial sliding of the steel pipe, and perform all-round locking and limiting, which can effectively prevent the steel pipe from deflecting or rotating, and ensure the stability of transportation.

[0041] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A steel pipe limiting device for a marine hook box, characterized in that: include: A main body (1), the main body (1) comprising a limiting sleeve (101) and a mounting seat (102), the mounting seat (102) being mounted on a fixed structure (3), the limiting sleeve (101) being arranged on the mounting seat (102), the limiting sleeve (101) being provided with a pipe-passing hole (1011) along its radial direction, the pipe-passing hole (1011) being used for allowing a steel pipe to pass through; A limiting assembly (2), the limiting assembly (2) comprising a limiting portion (201) and a locking member (202), the limiting portion (201) being rotatably arranged on the limiting sleeve (101), one end of the limiting portion (201) being used to abut against a steel pipe passing through the pipe hole (1011), the locking member (202) being connected to the other end of the limiting portion (201), the locking member (202) being movably arranged on the mounting seat (102), and having a locking position and an unlocking position within a movable range of the locking member (202), when the locking member (202) is located at the locking position, one end of the limiting portion (201) can abut against the steel pipe passing through the pipe hole (1011); when the locking member (202) is located at the unlocking position, one end of the limiting portion (201) does not abut against the steel pipe passing through the pipe hole (1011).

2. The offshore hook box steel pipe limiting device according to claim 1 is characterized in that: The limiting sleeve (101) extends in the up-down direction, one end of the limiting sleeve (101) is connected to the mounting seat (102), the limiting sleeve (101) is provided with a clearance hole (1012) along its radial direction, a hinged portion (103) is provided on the outer wall of the limiting sleeve (101), the hinged portion (103) is located below the clearance hole (1012), the limiting portion (201) comprises a first swing arm (2011) and a second swing arm (2012), the middle portion of the first swing arm (2011) The second swing arm (2012) is hinged in the clearance hole (1012), the middle part of the second swing arm (2012) is hinged on the hinge part (103), the upper end of the second swing arm (2012) is abutted against the lower end of the first swing arm (2011), and the locking member (202) comprises a locking bolt (2021), and the locking bolt (2021) passes through the lower end of the second swing arm (2012), the limiting sleeve (101) in sequence along the radial direction of the limiting sleeve (101), and is screwed to the mounting seat (102).

3. The offshore hook box steel pipe limiting device according to claim 2 is characterized in that: The first swing arm (2011) comprises a contact arm body (20111) and a counterweight arm body (20112), one end of the contact arm body (20111) is connected to one end of the counterweight arm body (20112), the contact arm body (20111) and the counterweight arm body (20112) are arranged at an angle, and the angle between the contact arm body (20111) and the counterweight arm body (20112) is 110° to 130°.

4. The offshore hook box steel pipe limiting device according to claim 3 is characterized in that: The hinged joint between the first swing arm (2011) and the clearance hole (1012) is located on the abutting arm body (20111), and the hinged joint between the first swing arm (2011) and the clearance hole (1012) is arranged close to the connection between the abutting arm body (20111) and the counterweight arm body (20112).

5. The offshore hook box steel pipe limiting device according to claim 2 is characterized in that: It comprises at least two of the limiting components (2), and the limiting sleeve (101) is provided with at least two clearance holes (1012) symmetrically circumferentially, and the clearance holes (1012) are hingedly connected to the first swing arm (2011) in a one-to-one correspondence.

6. The offshore hook box steel pipe limiting device according to claim 5 is characterized in that: The mounting seat (102) comprises an embedded part (1021), a seat body (1022) and a mounting bolt (1023); one end of the limiting sleeve (101) is arranged on the seat body (1022); the embedded part (1021) is embedded in the fixed structure (3); a mounting hole (10211) is provided on the embedded part (1021); the mounting hole (10211) has an internal thread; the mounting bolt (1023) passes through the seat body (1022) and engages with the mounting hole (10211) to mount the seat body (1022) on the embedded part (1021).

7. The offshore hook box steel pipe limiting device according to claim 6 is characterized in that: The mounting seat (102) further comprises a mounting block (1024), a mounting groove (10221) is provided on the seat body (1022), a part of the mounting block (1024) is shaped to be embedded in the mounting groove (10221), and the remaining part protrudes from the mounting groove (10221), a plurality of adjustment holes (10241) are provided on the outer peripheral wall of the mounting block (1024) protruding from the mounting groove (10221), the adjustment holes (10241) correspond one-to-one with the limit assembly (2), the adjustment holes (10241) have internal threads, the locking bolt (2021) is meshed with the adjustment hole (10241), and the mounting bolt (1023) extends in the up-down direction to sequentially pass through the mounting block (1024) and the seat body (1022) and mesh with the mounting hole (10211).

8. The offshore hook box steel pipe limiting device according to claim 7 is characterized in that: The upper end surface of the mounting bolt (1023) is tangent to the lower end of the pipe hole (1011), and a cushion layer (10231) is provided on the upper end surface of the mounting bolt (1023).

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