CN213419650U

CN213419650U - Thread anti-falling mechanism

Info

Publication number: CN213419650U
Application number: CN202021904183.7U
Authority: CN
Inventors: 赵伟东; 张丽平; 黄国军; 贾勇
Original assignee: Shenzhen Lehui Photoelectric Technology Co ltd
Current assignee: Shenzhen Lehui Photoelectric Technology Co ltd
Priority date: 2020-09-03
Filing date: 2020-09-03
Publication date: 2021-06-11
Anticipated expiration: 2030-09-03

Abstract

The utility model provides a screw thread anti-disengaging mechanism, wades threaded fastener technical field, solves its structure complicacy of current screw thread anti-disengaging mechanism, uses inconvenient, dismouting difficulty, the poor technique of anticreep effect not enough, and the technical means of adoption includes: the first connecting piece is provided with a connecting hole groove, and the screw rod is provided with a fastening step and a clamping column; the clamping column is slidably sleeved with a threaded sleeve, and the lower part of the threaded sleeve is provided with a clamping part; the connecting hole groove is provided with a fastening groove, and the fastening groove is provided with a clamping groove; the clamping column and the threaded sleeve are also provided with a bead-pushing positioning mechanism. The utility model discloses a top pearl positioning mechanism prescribes a limit to the swivel nut and is in the concrete position on the joint post to make the card portion of swivel nut lower part insert or break away from the card fixed slot and prevent the swivel nut to rotate or remove the injecing to the swivel nut, and then prevent the screw rod through the hole of swivel nut and joint post and rotate or drive screw rotates, play the fastening anticreep or disassemble the function of separation, compare in current screw thread anti-disengaging mechanism structure simpler, and dismantle the convenience, the anticreep is effectual.

Description

Thread anti-falling mechanism

Technical Field

The utility model relates to a threaded fastener technical field, more specifically relate to a screw thread anti-disengaging mechanism.

Background

Threaded fasteners are a widely used releasable, fixed attachment mechanism used on almost all mechanical devices and are one of the most important components to ensure reliable operation of mechanical systems. Common threaded fasteners include bolts, screws, and bolts, which are used to fixedly connect the first connecting member and the second connecting member, or to fix the position of the first connecting member. The threaded fastener has the advantages of simple structure, reliable connection, convenient assembly and disassembly and the like. However, after the existing threaded fastener such as a screw is screwed and fixed, abnormal conditions such as loosening and slipping can occur due to vibration of mechanical equipment after a period of time, so that the mechanical equipment parts fixed by the screw are connected abnormally, mechanical equipment faults are caused, and the life safety of field operators can be endangered in serious cases.

In order to avoid the loosening of the threaded fastener in the use process, a thread anti-loosening mechanism is required to be designed to ensure that the threaded fastener is not easy to loosen and slip after being screwed down. But current screw thread anti-disengaging mechanism often has the structure complicacy, uses inconveniently, dismouting difficulty, drawback such as anticreep effect is unsatisfactory, consequently, needs to improve current threaded fastener's screw thread anti-disengaging mechanism.

SUMMERY OF THE UTILITY MODEL

To sum up, the utility model discloses an it is complicated, use inconvenient, dismouting difficulty, the poor technique of anticreep effect of its structure of current screw thread anti-disengaging mechanism not enough to solve, and provide a screw thread anti-disengaging mechanism easy to assemble and dismantle, the anticreep is effectual.

In order to achieve the above purpose, the utility model adopts the following technical scheme:

the utility model provides a screw thread anti-disengaging mechanism, is including first connecting piece and screw rod, first connecting piece on be equipped with and peg graft the connecting hole groove of screw rod, the screw rod warp the connecting hole groove with first connecting piece thread fixed connection on other objects. The middle part of screw rod is equipped with radial extension's fastening step, and the upper portion of screw rod is equipped with axial extension's joint post, the joint post on sliding sleeve be equipped with one and drive the synchronous pivoted swivel nut of screw rod, the lower part of swivel nut is equipped with card portion. The connecting hole groove is provided with a fastening groove which is matched with and used for accommodating the fastening step so as to enable the screw rod to fasten the first connecting piece, and the fastening groove is provided with a clamping groove which is matched with and used for accommodating the clamping portion so as to prevent the screw sleeve from rotating. And the clamping column and the threaded sleeve are also provided with a top bead positioning mechanism for limiting the insertion or separation of the clamping part into or from the clamping groove.

The top ball positioning mechanism comprises a containing through hole which is radially communicated with the clamping column, a return spring is movably arranged in the containing through hole, two ends of the return spring are respectively elastically abutted against a positioning top ball which is movably arranged at the opening of the containing through hole, and a groove which is matched with the positioning top ball is correspondingly arranged on the wall surface of the inner hole of the threaded sleeve.

The groove comprises a first slot position for limiting the insertion of the clamping part into the clamping groove and a second slot position for limiting the separation of the clamping part from the clamping groove.

The clamping column and the threaded sleeve are also provided with a threaded sleeve anti-falling mechanism for preventing the threaded sleeve from separating from the clamping column.

The thread insert anti-falling mechanism comprises an anti-falling baffle connected to the top end of the clamping column, the upper portion of the thread insert is provided with a matching accommodating groove for accommodating the anti-falling baffle, the baffle accommodating groove is communicated with the inner hole of the thread insert, and the inner hole of the thread insert is positioned in the middle of the bottom surface of the baffle accommodating groove.

The utility model has the advantages that: the screw sleeve sleeved on the clamping column is twisted by using a tool such as a wrench and the like to synchronously drive the screw rod to rotate, the screw rod is screwed or loosened, and then the first connecting piece is fastened on other objects or is separated from other objects. After the screw rod is screwed up fixedly, press the swivel nut downwards to inject the position of swivel nut through a ball positioning mechanism, make the card portion of swivel nut lower part match the joint on the card fixed slot of first connecting piece, prevent the swivel nut rotatory, and then prevent in the use that the screw rod is not hard up or drops, realize the utility model discloses anticreep function. When the screw rod needs to be loosened, the screw sleeve only needs to be pulled out upwards, the position of the screw sleeve is limited through the bead pushing positioning mechanism, and the clamping part at the lower part of the screw sleeve is separated from the clamping groove. Then, the screw sleeve can be twisted by using tools such as a wrench and the like, the screw rod is driven to rotate through the screw sleeve, and the screw rod is unscrewed and detached, so that the first connecting piece is separated from other objects, and the detachment is simple and convenient. Compare in current screw thread anti-disengaging mechanism, the utility model discloses a structure is simpler, and the cost of manufacturing is lower, and the dismouting of screw rod is more convenient, and the anticreep effect is better.

Drawings

FIG. 1 is an exploded view of the overall structure of the present invention;

FIG. 2 is an exploded view of the screw of the present invention;

FIG. 3 is a cross-sectional view of the nut of the present invention;

FIG. 4 is a top view of the nut top structure of the present invention;

fig. 5 is a schematic cross-sectional structure diagram of a first connecting member according to the present invention;

fig. 6 is a top view of the first connector top structure of the present invention;

fig. 7 is one of the schematic cross-sectional views of the overall structure of the present invention;

fig. 8 is a schematic cross-sectional view of the overall structure of the present invention.

In the figure: 1. the anti-dropping device comprises a first connecting piece, 11 connecting hole grooves, 111 connecting via holes, 112 fastening grooves, 113 clamping grooves, 2 second connecting pieces, 3 screws, 4 connecting threads, 5 fastening steps, 6 clamping columns, 61 accommodating through holes, 62 return springs, 63 positioning top balls, 64 baffle fixing screw holes, 7 screw sleeves, 71 clamping portions, 72 stress portions, 73 inner holes, 74 baffle accommodating grooves, 75 grooves, 751 first groove positions, 752 second groove positions, 8 anti-dropping baffles, 81 baffle fixing studs and 82 cross grooves.

Detailed Description

The structure of the present invention will be further described with reference to the accompanying drawings and preferred embodiments of the present invention.

Referring to fig. 1 to 8, the present invention:

the utility model provides a screw thread anti-disengaging mechanism, is equipped with the connecting hole groove 11 that is used for pegging graft screw rod 3 including first connecting piece 1 and screw rod 3 on the first connecting piece 1, and the lower part of screw rod 3 is equipped with connecting thread 4, and screw rod 3 is through connecting thread 4 above and through the connecting hole groove 11 screw thread fixed connection on first connecting piece 1 on the surface of second connecting piece 2. And the second connecting piece 2 is provided with a connecting screw hole matched with the connecting thread 4 of the screw rod 3. The connecting thread 4 at the lower part of the screw rod 3 passes through the connecting hole slot 11 of the first connecting piece 1 to be fixedly connected with the connecting screw hole on the second connecting piece 2 by matching threads.

It should be noted that this embodiment is only a preferred embodiment of the present invention, and is not a limitation of the present invention. In this embodiment, the connection screw hole on the second connector 2 is a through hole structure penetrating up and down, and in other embodiments, the connection screw hole may also be a blind hole structure not penetrating up and down the second connector 2. It should be noted that, the overall shape and size of the first connecting member 1 and the second connecting member 2 shown in this embodiment are only for showing the connection mode between the two clearly, and are not limited to the present invention, and in other embodiments, the first connecting member 1 and the second connecting member 2 can be completely designed into a cylinder type, a triangular prism type, etc. and the contact surface between the two can be a horizontal plane, and can also be designed into an inclined plane, a curved surface, etc. according to actual requirements, as long as the screw thread fixing connection between the first connecting member 1 and the second connecting member 2 is not affected.

Specifically, refer to fig. 1 and 2 and show, the utility model discloses a 3 middle parts of screw rod be equipped with be in connecting thread 4 top, along 3 radial extensions of screw rod and with the fastening step 5 that 3 integrated into one piece of screw rod made, should fasten 5 preferred be the round platform structure, be equipped with on the centre of a circle of fastening step 5 upper surface along 3 axial upwards extensions of screw rod and with the joint post 6 that 3 integrated into one piece of screw rod made, this joint post 6 preferred is cuboid structure (regular quadrangular prism). A baffle fixing screw hole 64 is also arranged at the middle position of the top surface of the clamping column 6 with the cuboid structure.

It should be noted that the fastening step 5 and the snap-in post 6 in this embodiment are integrally formed with the screw rod 3 to improve the structural strength of the screw rod 3 itself, so that the fastening effect of the screw rod 3 is better. Meanwhile, the fastening step 5 adopts a circular truncated cone structure, so that the fastening step 5 does not block the rotation of the screw rod 3 in the process of screwing or loosening the screw rod 3. Certainly, in other embodiments, the fastening step 5 and the screw rod 3 may be connected by a split structure, for example, the fastening step 5 is designed to be a structure that the fastening step is rotatably sleeved on the middle position of the screw rod 3, so that the shape of the fastening step 5 can be designed according to actual requirements without adopting a circular table structure, but such design may affect the structural strength of the screw rod 3 itself, and certain disadvantages exist.

Specifically, referring to fig. 1 to 4, a threaded sleeve 7 capable of sliding up and down along the axial direction of the fastening column 6 and driving the fastening column 6 to rotate synchronously with the screw 3 is further slidably sleeved on the fastening column 6. Specifically, the outer peripheral shape of the upper portion of the screw sleeve 7 is the same as that of a common nut, and is a force receiving portion 72 having a regular hexagonal structure, and the screw sleeve 7 can be screwed through the force receiving portion 72 by using a tool such as a common wrench. The lower part of the screw sleeve 7 is provided with a locking part 71 with the shape and the size slightly smaller than the force receiving part 72, and the outer periphery of the locking part 71 is designed in a polygonal column structure. Note that the outer peripheral dimension of the locking portion 71 should be larger than the outer dimension of the fastening step 5 in the middle of the screw 3. An inner hole 73 which is matched with the clamping column 6 and penetrates through the screw sleeve 7 up and down is correspondingly arranged in the screw sleeve 7, the section of the inner hole 73 is square matched with the cross section of the clamping column 6, and the screw sleeve 7 is sleeved on the clamping column 6 through the inner hole 73 in a matching mode and slides up and down along the axial direction of the clamping column 6. When the stress part 72 of the screw sleeve 7 is screwed by external force, the screw sleeve 7 synchronously drives the clamping column 6 and the screw rod 3 to rotate through the inner hole 73, so that the screw rod 3 is screwed or loosened.

It should be noted that, the structural design of the fastening post 6 and the inner hole 73 in this embodiment is only a preferred embodiment, and is not a limitation of the present invention, the structure of the fastening post 6 in some other embodiments can completely adopt the structural design of polygonal column, elliptic column or spline shaft type, and then the inner hole 73 is designed to be matched with the structure, as long as it can satisfy that the screw sleeve 7 is sleeved on the fastening post 6 through the up-and-down sliding sleeve of the inner hole 73 and can drive the fastening post 6 and the screw rod 3 to rotate through the inner hole 73.

In cooperation, referring to fig. 1 and 5, the connecting hole groove 11 of the first connecting member 1 is correspondingly provided with a locking groove 113 for locking and limiting the locking portion 71 to prevent the screw sleeve 7 from rotating, an upper opening of the locking groove 113 is located on an upper end surface of the first connecting member 1, and a cross section of the locking groove 113 is matched with a cross section of the locking portion 71, and preferably, the cross section is in a regular octagonal structure. A fastening groove 112 for matching the circular groove structure for accommodating the fastening step 5 is correspondingly arranged below the locking groove 113, a connecting through hole 111 for passing the lower part of the screw rod 3 is also arranged below the fastening groove 112, and the inner wall of the connecting through hole 111 may be provided with an internal thread or not. It should be noted that the locking groove 113, the fastening groove 112, and the connection via 111 are coaxial and penetrate the first connector 1 up and down. Meanwhile, the shape and size of the fastening groove 112 should be slightly smaller than the shape and size of the locking groove 113 to ensure that the screw rod 3 can be inserted into the connecting hole groove 11 from top to bottom in a matching manner, and the fastening step 5 can be inserted into the fastening groove 112 in a matching manner.

The shape and structure of the locking portion 71 and the locking groove 113 in the present embodiment are only a preferred embodiment, and are not intended to limit the present invention. In other embodiments, the locking portion 71 and the locking groove 113 may also be designed as a spline shaft and spline cylinder, or other polygonal structures, as long as the locking portion 71 can be inserted into the locking groove 113 of the first connector 1 from top to bottom to prevent the screw sleeve 7 from rotating.

In order to prescribe a limit to the utility model discloses swivel nut 7 is in the concrete position on the joint post 6 to the card portion 71 of control swivel nut 7 lower part inserts or breaks away from card fixed slot 113, and then control screw 3's rotation, the utility model discloses still be equipped with a pearl positioning mechanism on swivel nut 7 and joint post 6.

Specifically, referring to fig. 2, 3, 7 and 8, the bead-pushing positioning mechanism includes an accommodating through hole 61 extending along the radial direction of the screw rod 3 and horizontally penetrating through the left and right side walls of the clamping column 6, and the accommodating through hole 61 is located at the middle position of the clamping column 6. A return spring 62 is movably disposed horizontally in the accommodating through hole 61, two ends of the return spring 62 are respectively abutted with a spherical positioning ejecting ball 63, and in a normal state, under the condition of no blocking, the return spring 62 elastically drives the two positioning ejecting balls 63 to eject out of openings at two ends of the accommodating through hole 61 respectively. And correspondingly, a groove 75 for accommodating and clamping the positioning top ball 63 is formed in the wall surface of the inner hole 73 of the screw sleeve 7.

Specifically, the groove 75 includes a first slot 751 corresponding to the upper portion of the wall surface of the inner hole 73 of the screw sleeve 7 and used for limiting the screw sleeve 7 at the lower portion of the clamping column 6 so that the clamping portion 71 can be inserted into the clamping slot 113; and a second groove 752 corresponding to the lower portion of the inner hole 73 of the screw sleeve 7 for limiting the screw sleeve 7 to the upper portion of the engaging column 6 so that the engaging portion 71 can be disengaged from the engaging groove 113.

It should be noted that, after the screw rod 3 is correspondingly inserted into the first connecting member 1, the receiving through hole 61 is higher than the upper surface of the first connecting member 1, so as to ensure that there is enough distance between the receiving through hole 61 and the upper surface of the fastening step 5 to enable the locking portion 71 to be separated from the locking groove 113.

The first slot 751 and the second slot 752 form two steps to define a specific position of the swivel nut 7.

First connecting piece 1 and second connecting piece 2 need be aligned at first during in-service use, make the connecting hole groove 11 with be connected the screw and be in same axis position, then match the screw rod 3 and peg graft on the connecting hole groove 11 of first connecting piece 1, through atress portion 72 and the twist on instrument centre gripping swivel nut 7 upper portion such as spanner, make connecting thread 4 of screw rod 3 lower part match in the connecting screw of screw in second connecting piece 2 under the drive of hole 73 of swivel nut 7 and joint post 6, fastening step 5 at the middle part of screw rod 3 supports tightly in fastening groove 112 of first connecting piece 1, make first connecting piece 1 screw thread fastening connect on second connecting piece 2, realize the utility model discloses the locking fixed function of screw rod 3.

Then the screw sleeve 7 is pressed downwards to slide downwards along the clamping column 6 until the positioning top ball 63 in the accommodating through hole 61 is abutted into the first slot 751 under the elastic driving of the return spring 62, so that the screw sleeve 7 is positioned at a first gear. At this time, the screw sleeve 7 is positioned at the lower part of the clamping column 6, the clamping part 71 is correspondingly inserted into the clamping groove 113, and the screw rod 3 is integrally locked and prevented from falling off. Even if the screw rod 3 itself is shaken to rotate under the state, the screw rod is restricted by the locking groove 113, the locking part 71, the inner hole 73 and the clamping column 6 at the same time and can not rotate, thereby realizing the anti-falling function of preventing the screw rod 3 from loosening.

When the screw 3 needs to be disassembled in order to remove the first connecting piece 1 from the second connecting piece 2, the screw sleeve 7 is pulled upwards with force, so that the positioning ejecting ball 63 is separated from the first slot 751 until the positioning ejecting ball 63 abuts against the second slot 752 under the elastic driving of the return spring 62, and the screw sleeve 7 is positioned at the second gear. At this time, the screw sleeve 7 is positioned at the upper part of the engaging column 6, the engaging portion 71 is disengaged from the engaging groove 113, and the screw 3 is formed in a state of being able to be screwed. Can use instruments such as spanner to twist the swivel nut 7 through the atress portion 72 on swivel nut 7 upper portion under this state to rotate through swivel nut 7

hole

73 and 6 drive screw 3 of joint post, then unscrew screw rod 3 and take off it, make first connecting piece 1 and the separation of second connecting piece 2, make the utility model discloses a dismantlement is more convenient.

Compare in current screw thread anti-disengaging mechanism the utility model discloses a structure is simpler, and manufacturing cost is lower, and dismouting convenient to use, but reuse.

It should be noted that this embodiment pushes up pearl positioning mechanism and has only set up a holding through-hole 61, and this design can reduce the utility model discloses the manufacturing cost of screw rod 3 can set up two or more holding through-holes 61 and correspondingly increase the trench of recess 75 on joint post 6 completely in some other embodiments to strengthen the spacing dynamics of a pearl positioning mechanism to swivel nut 7.

Further, break away from joint post 6 in order to prevent swivel nut 7, avoid dismantling swivel nut 7 on the back screw rod 3 and lose, perhaps in the use because the power of exerting oneself is too big and pull out swivel nut 7 outside joint post 6, lead to location knob 63 and reset spring 62 to pop out, drop or lose, the utility model discloses still be equipped with swivel nut anti-disengaging mechanism on joint post 6 and the swivel nut 7.

Specifically, referring to fig. 1 to 3 and 7 to 8, the thread insert retaining mechanism of the present invention includes a retaining plate 8 fixedly connected to the top end of the clamping column 6 by a screw thread. Preferably, the anti-dropping baffle 8 is of a screw-type structure, the upper part of the anti-dropping baffle is of a disc-type structure, an inward concave cross groove 82 is formed in the middle position of the upper surface of the disc-type structure, a baffle fixing stud 81 extending downwards is formed in the middle position of the lower surface of the disc-type structure, and an external thread matched with the baffle fixing screw hole 64 in the top of the clamping column 6 is formed in the periphery of the baffle fixing stud 81. In cooperation, the upper portion of the threaded sleeve 7 is provided with a baffle receiving groove 74 matching with the circular groove structure for receiving the anti-falling baffle 8, the baffle receiving groove 74 is communicated with the inner hole 73 of the threaded sleeve 7, and the inner hole 73 of the threaded sleeve 7 is positioned at the position below the middle portion of the bottom surface of the baffle receiving groove 74 and is positioned on the same axis.

Referring to fig. 7 and 8, in actual assembly, firstly, the screw sleeve 7 is fitted over the fastening column 6 on the upper portion of the screw rod 3 through the inner hole 73, and the first slot 751 on the wall surface of the inner hole 73 of the screw sleeve 7 is locked to the positioning top bead 63 of the fastening column 6 by downward force, so that the screw sleeve 7 is located at the lower portion of the fastening column 6. Preferably, the top of the clamping column 6 is slightly lower than the top of the screw sleeve 7, and then the anti-dropping baffle 8 is fixedly connected to the top of the clamping column 6 through the baffle fixing stud 81 and the baffle fixing screw hole 64 by a cross screwdriver through a cross slot 82 on the disc type structure. After the anti-falling baffle 8 is screwed down and fixed, the disc-type structure upper surface of the anti-falling baffle 8 is just level with the top of the screw sleeve 7. When the screw sleeve 7 is pulled out upwards to enable the second groove 752 to be clamped on the positioning top bead 63 of the clamping column 6, the lower surface of the disc type structure of the anti-falling baffle 8 is just abutted against the bottom surface of the baffle accommodating groove 74.

When the thread insert 7 is pulled out upwards, the positions of the highest points of the thread insert 7 can be limited by the lower bottom surface of the disc type structure of the anti-falling baffle 8 and the bottom surface of the baffle containing groove 74, so that the thread insert 7 is prevented from moving upwards under the stress, and the effect of preventing the thread insert 7 from being separated from the screw rod 3 is achieved. Meanwhile, the height of the baffle receiving groove 74 in this embodiment is designed to ensure that the anti-falling baffle 8 does not protrude from the top of the screw sleeve 7 when the screw sleeve 7 is pushed downward to make the locking portion 71 be inserted into the locking groove 113.

It should be explained simultaneously, the connected mode between anticreep baffle 8 and the joint post 6 in this embodiment is not right the utility model discloses a restriction, anticreep baffle 8 adopt similar screw rod 3's structure is more firm in order to make the connection between joint post 6 and the anticreep baffle 8, can not loosen easily and take off. In other embodiments, the structure of the anti-dropping baffle 8 can be designed according to actual needs, for example, a gap-embedded design can be adopted to enable the anti-dropping baffle 8 to be embedded on the top of the clamping column 6, and the like.

The above examples are merely for clarity of description of specific embodiments of the present invention and are not intended to limit the embodiments of the present invention. For those skilled in the art, the present invention can derive and summarize other adjustments or changes to the screw rod 3, the fastening step 5, the fastening column 6, the threaded sleeve 7, the locking portion 71, the fastening groove 112, the locking groove 113, and the top bead positioning mechanism, which are not listed here. Any modification, replacement or improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A thread anti-drop mechanism comprises a first connecting piece (1) and a screw rod (3), wherein a connecting hole groove (11) for inserting the screw rod (3) is formed in the first connecting piece (1), and the screw rod (3) fixedly connects the first connecting piece (1) to other objects through the connecting hole groove (11); the method is characterized in that: the middle part of the screw rod (3) is provided with a fastening step (5) extending in the radial direction, the upper part of the screw rod (3) is provided with a clamping column (6) extending in the axial direction, the clamping column (6) is sleeved with a threaded sleeve (7) capable of driving the screw rod (3) to rotate synchronously in a sliding mode, and the lower part of the threaded sleeve (7) is provided with a clamping part (71); a fastening groove (112) which is matched with and used for accommodating the fastening step (5) so that the screw (3) can fasten the first connecting piece (1) is arranged on the connecting hole groove (11), and a clamping groove (113) which is matched with and used for accommodating the clamping part (71) so as to prevent the screw sleeve (7) from rotating is arranged on the fastening groove (112); the clamping column (6) and the threaded sleeve (7) are further provided with a top bead positioning mechanism for limiting the insertion or separation of the clamping portion (71) into or from the clamping groove (113).

2. The thread run-off prevention mechanism of claim 1, wherein: the top pearl positioning mechanism including radially having a perfect understanding the holding through-hole (61) of joint post (6), holding through-hole (61) internalization be equipped with a reset spring (62), the both ends of reset spring (62) are elastic butt one activity respectively and are in location top pearl (63) of holding through-hole (61) opening part, the correspondence is equipped with the matching card on hole (73) wall of swivel nut (7) fixes a position recess (75) of pearl (63).

3. The thread run-off prevention mechanism of claim 2, wherein: the groove (75) includes a first groove (751) defining the insertion of the locking portion (71) into the locking groove (113), and a second groove (752) defining the disengagement of the locking portion (71) from the locking groove (113).

4. The thread run-off prevention mechanism of claim 1, wherein: the clamping column (6) and the threaded sleeve (7) are also provided with a threaded sleeve anti-falling mechanism for preventing the threaded sleeve (7) from separating from the clamping column (6).

5. The thread run-off prevention mechanism of claim 4, wherein: the thread insert anti-falling mechanism comprises an anti-falling baffle (8) connected to the top end of the clamping column (6), the upper portion of the thread insert (7) is provided with a baffle accommodating groove (74) matched with and accommodating the anti-falling baffle (8), the baffle accommodating groove (74) is communicated with an inner hole (73) of the thread insert (7), and the inner hole (73) of the thread insert (7) is positioned below the middle part of the bottom surface of the baffle accommodating groove (74).