Screw placement depth measuring device

Abstract

The invention provides a screw placement depth measuring device, and belongs to the technical field of medical instruments. Comprising a rod body and a rotating handle installed on the top of the rod body. A detection part is arranged in the middle of the rod body, the detection part is used for displaying the implantation depth of the screw in real time according to the number of rotation turns of the rod body, a feedback part is installed on the detection part, and the feedback part is used for providing continuously-enhanced pressure feedback at the rear half section of the implanted screw. By arranging the detection part, the screw-in depth of the screw can be quickly and accurately read out through the scales, so that the condition that the screw is screwed too deep or too shallow is avoided, and the injury of an operation to a patient is reduced, and when the rotating handle is reversely rotated, the detection sleeve moves towards one end far away from the rotating handle in the axial direction of the rod body, and the screw-in depth can be quickly and accurately read out. The accuracy and the reliability of the numerical value read through the first scale and the window when the rotating handle rotates reversely are guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of medical instruments, and in particular to a screw insertion depth measuring device. Background Art

[0002] In spinal surgery, the depth of screw implantation is crucial to the success of the operation. The screw needs to be precisely implanted into the vertebral body to ensure stability and avoid damage. During the operation, doctors usually use Kirschner wires for initial positioning and measure the expected implantation depth of the screw. However, in actual operation, it is difficult for doctors to accurately judge the depth to which the screw has been screwed. If the screw is too deep, it may cause vertebral penetration, damage the spinal cord or nerve roots, and cause serious nerve damage. If the screw is too shallow, it may lead to loose fixation, affect postoperative stability, and increase the risk of reoperation.

[0003] Currently, intraoperative fluoroscopy techniques (such as X-ray fluoroscopy) are used to check the implantation depth of the screws. However, this method may increase the operation time and radiation exposure, and has certain limitations in real-time and accuracy. In order to observe the implantation depth of the screws in a timely manner and ensure the accuracy and reliability of the read values, we provide a screw insertion depth measurement device to meet the needs. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a screw insertion depth measuring device to solve the limitations of the existing screw depth detection in terms of real-time and accuracy during implantation.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] A screw insertion depth measuring device comprises a rod body and a handle mounted on the top of the rod body; a detection component is arranged in the middle of the rod body, the detection component is used to display the implantation depth of the screw in real time according to the number of rotations of the rod body, a feedback component is installed on the detection component, the feedback component is used to provide continuously enhanced pressure feedback in the second half of the screw implantation; a first external thread is arranged in the middle of the rod body, a bearing is fixedly sleeved on the rod body, and the bearing is located at the end of the first external thread away from the handle.

[0007] Optionally, the detection component includes a detection sleeve threadedly connected to the rod body through a first external thread, the detection sleeve is provided with a first threaded hole penetrating the detection sleeve, the first threaded hole is adapted to the first external thread, the detection component also includes a holding sleeve rotatably connected to the outside of the rod body through a bearing, a first limiting rib arranged along the axial direction of the rod body is provided on the inner wall of the holding sleeve, the detection sleeve is sleeved in the first limiting rib, the detection sleeve is provided with a first limiting groove adapted to the first limiting rib, the detection sleeve is provided with a plurality of first scales arranged along the axial direction of the rod body, and the holding sleeve is provided with a window corresponding to the first scale position; a limiting component for limiting the simultaneous movement of the detection sleeve and the first external thread is installed on the holding sleeve.

[0008] Optionally, the feedback component includes a second threaded hole opened on the inner wall of the window, the second threaded hole is located above the first limiting rib and has a gap between the second threaded hole and the first limiting rib, the top of the holding sleeve is sleeved with a top cover, the top inner wall of the top cover is provided with a cylinder deep into the holding sleeve, a second external thread matched with the second threaded hole is opened on the outside of the cylinder, a first elastic member is installed at the bottom of the second external thread, one end of the first elastic member away from the second external thread faces the detection sleeve, and the holding sleeve is provided with a plurality of second scales arranged along the axial direction of the rod body, and the top cover is rotated under force and translates along the axial direction of the holding sleeve, and the second scale is used to detect the position of the bottom of the top cover after the translation.

[0009] Optionally, a through groove running through the holding sleeve is provided on the holding sleeve; a plurality of second limiting grooves are evenly provided on the outer side of the top cover along the circumference; a clamping groove is provided on the outer side of the detection sleeve, and the clamping groove is arranged flush with the zero scale of the first scale; the limiting component also includes a clamping ring slidably connected to the through groove, a pressure plate is provided on the side of the clamping ring outside the detection sleeve, a gap is provided between the pressure plate and the detection sleeve, a warping portion bent toward the detection sleeve is provided at the bottom of the pressure plate, an extension portion extending along the axial direction of the rod body is provided on the top of the pressure plate, and a second limiting rib adapted to any second limiting groove is provided on the side of the extension portion close to the detection sleeve, when the end of the warping portion away from the pressure plate contacts the detection sleeve, the clamping ring is clamped with the clamping groove, and the clamping ring is located at the zero scale position on the first scale, when the clamping ring is detached from the clamping groove, the warping portion is subjected to force to produce elastic deformation, and the second limiting rib is clamped with the second limiting groove.

[0010] Optionally, a wing plate is provided on the top of the extension portion, the wing plate is arc-shaped, and the inner diameter of the wing plate is the same as the outer diameter of the top cover.

[0011] Optionally, a first through hole coaxial with the rod body is opened in the middle of the column, and the inner diameter of the first through hole is larger than the outer diameter of the rod body.

[0012] Optionally, a guiding opening is provided at the bottom of the first limiting groove.

[0013] Optionally, the first elastic member is a conical spring and is sleeved outside the rod.

[0014] Optionally, a first retreat groove is provided at the bottom of the column, and second retreat grooves are provided at the top and bottom of the detection sleeve. After the detection sleeve and the column collide, the height of the cavity formed between the first retreat groove and the second retreat groove is adapted to the diameter of the first elastic member.

[0015] Optionally, a second elastic member is installed at the bottom of the detection sleeve, the second elastic member is a conical spring and is sleeved outside the rod body, and one end of the second elastic member away from the detection sleeve is in conflict with the bearing.

[0016] Optionally, the pressure plate is arranged on one side of the window and does not overlap with the window.

[0017] Compared with the prior art, the present invention has at least the following beneficial effects:

[0018] In the above scheme, by setting up a detection component, the screw insertion depth can be quickly and accurately read through the scale, thereby avoiding the situation where the screw is screwed in too deeply or too shallowly, reducing the damage of the operation to the patient. When the handle is rotated in the opposite direction, the detection sleeve moves along the axial direction of the rod body toward the end away from the handle, ensuring the accuracy and reliability of the value read through the first scale and the window when the handle is reversed.

[0019] By providing a feedback component, before the screw screwed into the affected part is about to reach a predetermined position, the first elastic member contacts the detection sleeve, and the movement resistance of the detection sleeve is increased by the elastic force of the first elastic member itself, and the force is then transmitted to the screw handle through the detection sleeve, thereby realizing the feedback function. The advantage of such a setting is that after the first elastic member contacts the detection sleeve, the operator senses the resistance, can slow down the screwing speed, and observe whether the first scale at the window position reaches the predetermined value, thereby improving the safety of the operation through real-time feedback and detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the three-dimensional structure of the screw insertion depth measuring device;

[0021] Figure 2 A cross-sectional view of a screw insertion depth measuring device;

[0022] Figure 3 It is a schematic diagram of the three-dimensional structure of the holding sleeve;

[0023] Figure 4 It is a cross-sectional view of the holding sleeve;

[0024] Figure 5It is a schematic diagram of the three-dimensional structure of the detection sleeve, top cover and rod body assembly;

[0025] Figure 6 It is a schematic diagram of the three-dimensional structure of the detection sleeve;

[0026] Figure 7 It is a schematic diagram of the three-dimensional structure after the detection sleeve and the limiting component are assembled;

[0027] Figure 8 It is a schematic diagram of the three-dimensional structure of the limiting component;

[0028] Fig. 9 It is a schematic diagram of the three-dimensional structure of the top cover.

[0029] Reference numerals

[0030] 1. Rod body; 2. Turning handle; 3. Detection component; 4. Feedback component; 5. First external thread; 6. Detection sleeve; 7. First threaded hole; 8. Bearing; 9. Holding sleeve; 10. First limiting rib; 11. First limiting groove; 12. First scale; 13. Window; 14. Second threaded hole; 15. Top cover; 16. Cylinder; 17. Second external thread; 18. Second scale; 19. First elastic member; 20. Slot; 21. Snap ring; 22. Press plate; 23. Warping portion; 24. First through hole; 25. First retreat groove; 26. Second retreat groove; 27. Second limiting groove; 28. Extension portion; 29. ​​Second limiting rib; 30. Wing plate; 31. Second elastic member; 32. Limiting component; 33. Through groove.

[0031] As shown in the figure, in order to clearly implement the structure of the embodiment of the present invention, specific structures and devices are marked in the figure, but this is only for illustrative purposes and is not intended to limit the present invention to the specific structure, device and environment. According to specific needs, ordinary technicians in this field can adjust or modify these devices and environments, and the adjustments or modifications made are still included in the scope of the attached claims. DETAILED DESCRIPTION

[0032] The following is a detailed description of a screw insertion depth measuring device provided by the present invention in conjunction with the accompanying drawings and specific embodiments. At the same time, it is explained here that in order to make the embodiments more detailed, the following embodiments are the best and preferred embodiments, and those skilled in the art may also adopt other alternative methods to implement some known technologies; and the accompanying drawings are only for a more specific description of the embodiments, and are not intended to specifically limit the present invention.

[0033] like Figures 1 to 9As shown, an embodiment of the present invention provides a screw insertion depth measuring device, comprising a rod body 1 and a handle 2 installed on the top of the rod body 1. The end of the rod body 1 away from the handle 2 is generally provided with a screw tightening mechanism compatible with different types of screws, which is used to cooperate with the rotation of the rod body 1 to realize the tightening of different types of screws; a detection component 3 is provided in the middle of the rod body 1, and the detection component 3 is used to display the implantation depth of the screw in real time according to the number of rotations of the rod body 1. A first external thread 5 is provided in the middle of the rod body 1, and a bearing 8 is fixedly sleeved on the rod body 1, and the bearing 8 is located at the end of the first external thread 5 away from the handle 2.

[0034] The detection component 3 includes a detection sleeve 6 threadedly connected to the rod body 1 through a first external thread 5, and a first threaded hole 7 penetrating the detection sleeve 6 is provided on the detection sleeve 6, and the first threaded hole 7 is adapted to the first external thread 5. The detection component 3 also includes a holding sleeve 9 rotatably connected to the outside of the rod body 1 through a bearing 8, and a first limiting rib 10 arranged axially along the rod body 1 is provided on the inner wall of the holding sleeve 9. The detection sleeve 6 is sleeved in the first limiting rib 10, and a first limiting groove 11 adapted to the first limiting rib 10 is provided on the detection sleeve 6. A plurality of first scales 12 arranged axially along the rod body 1 are provided on the detection sleeve 6, and a window 13 corresponding to the position of the first scale 12 is provided on the holding sleeve 9.

[0035] When it is necessary to implant a screw into the patient's body, the operator holds the sleeve 9 with one hand and screws the handle 2 with the other hand. The handle 2 drives the screw screwing unit to rotate through the rod body 1 and screws the screw into the affected area. During this process, the detection sleeve 6 is restricted by the first limiting groove 11 and the first limiting rib 10 and moves along the axial direction of the rod body 1 to the side close to the handle 2 under the action of the first external thread 5 and the first threaded hole 7, thereby changing the position of the first scale 12 relative to the window 13. This arrangement allows the screw-in depth to be quickly and accurately read through the scale, reducing the damage to the patient caused by the operation.

[0036] When the knob 2 is rotated in the reverse direction, the detection sleeve 6 moves along the axial direction of the rod body 1 toward the end away from the knob 2, thereby ensuring the accuracy and reliability of the values ​​read through the first scale 12 and the window 13 when the knob 2 is reversed.

[0037] It should be noted that before the operation, the knob 2 needs to be turned to display the zero mark of the first scale 12 of the detection sleeve 6 at the position of the window 13, so as to read the detection reading simply and directly, reducing the difficulty of reading.

[0038] like Figures 1 to 8As shown, a feedback component 4 is installed on the detection component 3, and the feedback component 4 is used to provide continuously enhanced pressure feedback in the second half of the screw implantation; the feedback component 4 includes a second threaded hole 14 opened on the inner wall of the window 13, and the second threaded hole 14 is located above the first limiting rib 10 and has a gap between the first limiting rib 10, and a top cover 15 is sleeved on the top of the window 13, and the top inner wall of the top cover 15 is provided with a column 16 protruding into the holding sleeve 9, and a second external thread 17 matched with the second threaded hole 14 is opened on the outside of the column 16, and a first elastic member 19 is installed at the bottom of the second external thread 17, and the end of the first elastic member 19 away from the second external thread 17 faces the detection sleeve 6, and a plurality of second scales 18 arranged along the axial direction of the rod body 1 are provided on the holding sleeve 9. After the top cover 15 is rotated under force, it translates along the axial direction of the holding sleeve 9, and the second scale 18 is used to detect the position of the bottom of the top cover 15 after the translation.

[0039] Before the screw screwed into the affected part is about to reach the predetermined position, the first elastic member 19 contacts the detection sleeve 6, and the elastic force of the first elastic member 19 itself increases the movement resistance of the detection sleeve 6, and then the force is transmitted to the screw handle 2 through the detection sleeve 6, thereby realizing the feedback function. The advantage of this arrangement is that after the first elastic member 19 contacts the detection sleeve 6, the operator senses the resistance and can slow down the screwing speed and observe whether the first scale 12 at the position of the window 13 reaches the predetermined value, thereby improving the safety of the operation through real-time feedback and detection.

[0040] like Figure 2 , Figure 3 , Figures 6 to 9 As shown, a limiting component 32 for limiting the simultaneous movement of the detection sleeve 6 and the first external thread 5 is installed on the holding sleeve 9, and a through groove 33 penetrating the holding sleeve 9 is provided on the holding sleeve 9; a plurality of second limiting grooves 27 are evenly provided along the circumference of the outer side of the top cover 15, and a clamping groove 20 is provided on the outer side of the detection sleeve 6, and the clamping groove 20 is arranged flush with the zero scale of the first scale 12; the limiting component 32 also includes a clamping ring 21 slidably connected to the through groove 33, and a pressure plate 22 is provided on one side of the clamping ring 21 outside the detection sleeve 6, and a gap is provided between the pressure plate 22 and the detection sleeve 6, and the pressure plate 2 2 is provided with a warping portion 23 bent toward the detection sleeve 6, and an extension portion 28 extending axially along the rod body 1 is provided on the top of the pressure plate 22. A second limiting rib 29 adapted to any second limiting groove 27 is provided on the side of the extension portion 28 close to the detection sleeve 6. When the end of the warping portion 23 away from the pressure plate 22 contacts the detection sleeve 6, the clamping ring 21 is clamped with the clamping groove 20, and the clamping ring 21 is located at the zero scale position on the first scale 12. When the clamping ring 21 is separated from the clamping groove 20, the warping portion 23 is subjected to force to produce elastic deformation, and the second limiting rib 29 is clamped with the second limiting groove 27.

[0041] Before implanting the screw, if it is necessary to adjust the screw-in depth, the top cover 15 can be directly rotated forward or reversed when the retaining ring 21 is engaged in the retaining groove 20, so that the top cover 15 moves upward or downward along the axial direction of the rod body 1 under the action of the second external thread 17 and the second threaded hole 14, thereby limiting the height of the axial movement of the detection sleeve 6 along the rod body 1, and further limiting the number of rotations of the rod body 1, thereby limiting the screw-in depth of the screw, and the adjustment operation is simple and convenient.

[0042] Before the screw needs to be implanted, the pressure plate 22 is pressed toward the side close to the detection sleeve 6, and the warping portion 23 is subjected to elastic deformation. When the clamping ring 21 is removed from the slot 20, the second limiting rib 29 is inserted into the second limiting groove 27. At this time, the handle 2 can be rotated. When the height difference between the clamping ring 21 and the slot 20 is generated, the pressing of the pressure plate 22 can be released. In this state, the clamping ring 21 contacts the outer side of the detection sleeve 6, and the warping portion 23 remains deformed. At the same time, the second limiting rib 29 remains in engagement with the second limiting groove 27. This arrangement allows the detection sleeve 6 or the top cover 15 to be restricted by the limiting component 32, and only one of them can move at the same time, thereby avoiding the other moving due to accidental touching during the adjustment of the top cover 15 or the detection sleeve 6, thereby ensuring the accuracy of the screw-in depth. This arrangement can also ensure that after the adjustment of the device is completed, the detection sleeve 6 is always kept at the zero scale line without pressing the pressure plate 22, thereby improving the convenience of use of the device.

[0043] like Figure 8 As shown, a wing plate 30 is provided at the top of the extension portion 28. The wing plate 30 is arc-shaped, and the inner diameter of the wing plate 30 is the same as the outer diameter of the top cover 15. The advantage of such a setting is that when the handle 2 is turned, the wing plate 30 fits tightly with the outer surface of the top cover 15, reducing the probability of the top cover 15 rotating due to accidental force, further improving the limit stability of the top cover 15, and ensuring the screw-in accuracy of the screw.

[0044] like Figure 5 and Fig. 9 As shown, a first through hole 24 coaxial with the rod body 1 is opened in the middle of the column 16, and the inner diameter of the first through hole 24 is larger than the outer diameter of the rod body 1. The advantage of this arrangement is that when the handle 2 drives the rod body 1 to rotate, friction between the rod body 1 and the first through hole 24 is avoided, thereby reducing the rotation resistance of the rod body 1.

[0045] like Figure 7 As shown, a guide opening is provided at the bottom of the first limiting groove 11. The advantage of such a setting is that the fault tolerance of the first limiting rib 10 being inserted into the first limiting groove 11 when the holding sleeve 9 is mounted on the detection sleeve 6 is improved, thereby increasing the installation convenience of the holding sleeve 9.

[0046] like Figure 6As shown, the first elastic member 19 is a conical spring and is sleeved outside the rod body 1. The advantage of such a configuration is that when the detection sleeve 6 approaches the column 16 along the axial direction of the rod body 1, the detection sleeve 6 will first contact with the bottom of the first elastic member 19 and gradually squeeze the first elastic member 19. The compressed first elastic member 19 will collapse in an orderly manner and increase the reaction force on the detection sleeve 6. Compared with the straight cylindrical spring, the conical spring can collapse in an orderly manner into a disc shape after being stressed, which effectively increases the activity space of the detection sleeve 6, reduces the overall reserved length of the device, avoids deformation damage caused by its disordered collapse, and ensures the service life of the first elastic member 19.

[0047] like Figure 7 and Figure 8 As shown, a first retreat groove 25 is provided at the bottom of the column 16, and a second retreat groove 26 is provided at the top and the bottom of the detection sleeve 6. After the detection sleeve 6 and the column 16 collide with each other, the height of the cavity formed between the first retreat groove 25 and the second retreat groove 26 is adapted to the diameter of the first elastic member 19. The advantage of such a setting is that when the spiral first elastic member 19 collapses into a disc shape, the edges of the first retreat groove 25 and the second retreat groove 26 will collide with each other, and a cavity for accommodating the first elastic member 19 is generated through the first retreat groove 25 and the second retreat groove 26, thereby avoiding excessive extrusion of the first elastic member 19, increasing the service life of the first elastic member 19, and ensuring the stability of the use of the first elastic member 19.

[0048] like Figure 6 As shown, a second elastic member 31 is installed at the bottom of the detection sleeve 6. The second elastic member 31 is a conical spring and is sleeved outside the rod body 1. The end of the second elastic member 31 away from the detection sleeve 6 is in conflict with the bearing 8. When the zero scale of the first scale 12 is displayed at the window 13, if the rotation direction of the handle 2 is wrong, the elastic support applied to the detection sleeve 6 by the second elastic member 31 will be fed back to the handle 2 in time, reducing the probability of erroneous operation. Furthermore, when the detection sleeve 6 moves to the lowest point along the axial direction of the rod body 1, the spiral second elastic member 31 collapses into a disc shape, so that the force applied by the detection sleeve 6 and the bearing 8 on the second elastic member 31 can be evenly borne by various parts of the second elastic member 31, avoiding the second elastic member 31 from being squeezed and damaged, thereby increasing the service life of the second elastic member 31.

[0049] like Figure 3 and Figure 4 As shown, the pressure plate 22 is arranged on one side of the window 13 and does not overlap with the window 13. The advantage of such arrangement is that the pressure plate 22 is prevented from blocking the window 13, thereby reducing interference when reading the indication in the window 13.

[0050] The specific working process of the technical solution provided by the present invention is as follows:

[0051] When it is necessary to implant a screw into the patient's body, the operator holds the sleeve 9 with one hand and screws the handle 2 with the other hand. The handle 2 drives the screw screwing unit to rotate through the rod body 1 and screws the screw into the affected area. During this process, the detection sleeve 6 is restricted by the first limiting groove 11 and the first limiting rib 10 and moves along the axial direction of the rod body 1 to the side close to the handle 2 under the action of the first external thread 5 and the first threaded hole 7, thereby changing the position of the first scale 12 relative to the window 13. This arrangement allows the screw-in depth to be quickly and accurately read through the scale, reducing the damage to the patient caused by the operation.

[0052] When the knob 2 is rotated in the reverse direction, the detection sleeve 6 moves along the axial direction of the rod body 1 toward the end away from the knob 2, thereby ensuring the accuracy and reliability of the values ​​read through the first scale 12 and the window 13 when the knob 2 is reversed.

[0053] Before the screw screwed into the affected part is about to reach the predetermined position, the first elastic member 19 contacts the detection sleeve 6, and the elastic force of the first elastic member 19 itself increases the movement resistance of the detection sleeve 6, and then the force is transmitted to the screw handle 2 through the detection sleeve 6, thereby realizing the feedback function. The advantage of this arrangement is that after the first elastic member 19 contacts the detection sleeve 6, the operator senses the resistance and can slow down the screwing speed and observe whether the first scale 12 at the position of the window 13 reaches the predetermined value, thereby improving the safety of the operation through real-time feedback and detection.

[0054] 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 modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A screw insertion depth measuring device, comprising a rod body and a handle mounted on the top of the rod body; characterized in that: A detection component is provided in the middle of the rod body, and the detection component is used to display the implantation depth of the screw in real time according to the number of rotations of the rod body. A feedback component is installed on the detection component, and the feedback component is used to provide increasing pressure feedback in the latter half of the screw implantation. A first external thread is provided in the middle of the rod body, a bearing is fixedly sleeved on the rod body, and the bearing is located at an end of the first external thread away from the handle; The detection component includes a detection sleeve threadedly sleeved on the rod body through a first external thread, a first threaded hole penetrating the detection sleeve is provided on the detection sleeve, and the first threaded hole is adapted to the first external thread, the detection component also includes a holding sleeve rotatably sleeved on the outside of the rod body through a bearing, a first limiting rib arranged along the axial direction of the rod body is provided on the inner wall of the holding sleeve, the detection sleeve is sleeved in the first limiting rib, a first limiting groove adapted to the first limiting rib is provided on the detection sleeve, a plurality of first scales arranged along the axial direction of the rod body are provided on the detection sleeve, and a window corresponding to the position of the first scale is provided on the holding sleeve; The holding sleeve is provided with a limiting component for limiting the simultaneous movement of the detection sleeve and the first external thread.

2. The screw insertion depth measuring device according to claim 1, characterized in that: The feedback component includes a second threaded hole opened on the inner wall of the window, the second threaded hole is located above the first limiting rib and has a gap between the second threaded hole and the first limiting rib, a top cover is sleeved on the top of the window, the top inner wall of the top cover is provided with a column protruding into the holding sleeve, a second external thread matched with the second threaded hole is opened on the outside of the column, a first elastic member is installed at the bottom of the second external thread, one end of the first elastic member away from the second external thread faces the detection sleeve, and a plurality of second scales arranged along the axial direction of the rod body are provided on the holding sleeve, and the top cover is rotated under force and translates along the axial direction of the holding sleeve, and the second scale is used to detect the position of the bottom of the top cover after the translation.

3. The screw insertion depth measuring device according to claim 2, characterized in that: The holding sleeve is provided with a through groove penetrating the holding sleeve; A plurality of second limit grooves are evenly arranged along the circumference of the outer side of the top cover, and a clamping groove is arranged on the outer side of the detection sleeve, and the clamping groove is arranged flush with the zero scale of the first scale; The limiting component also includes a snap ring slidably connected to the through groove, a pressure plate is provided on one side of the snap ring outside the detection sleeve, a gap is provided between the pressure plate and the detection sleeve, a warping portion bent toward the detection sleeve is provided at the bottom of the pressure plate, an extension portion extending along the axial direction of the rod body is provided at the top of the pressure plate, a second limiting rib adapted to any second limiting groove is provided on the side of the extension portion close to the detection sleeve, when the end of the warping portion away from the pressure plate contacts the detection sleeve, the snap ring is engaged with the engaging groove, and the snap ring is located at the zero scale position on the first scale, when the snap ring is detached from the engaging groove, the warping portion is subjected to force to produce elastic deformation, and the second limiting rib is engaged with the second limiting groove.

4. The screw insertion depth measuring device according to claim 3, characterized in that: A wing-shaped plate is arranged on the top of the extension portion. The wing-shaped plate is arc-shaped, and the inner diameter of the wing-shaped plate is the same as the outer diameter of the top cover.

5. The screw insertion depth measuring device according to claim 2, characterized in that: A first through hole coaxial with the rod body is opened in the middle of the column, and the inner diameter of the first through hole is larger than the outer diameter of the rod body.

6. The screw insertion depth measuring device according to claim 1, characterized in that: A guiding opening is formed at the bottom of the first limiting groove.

7. The screw insertion depth measuring device according to claim 2, characterized in that: The first elastic member is a conical spring and is sleeved outside the rod.

8. The screw insertion depth measuring device according to claim 2, characterized in that: The bottom of the column is provided with a first retreat groove, and the top and bottom of the detection sleeve are provided with second retreat grooves. After the detection sleeve and the column collide, the height of the cavity formed between the first retreat groove and the second retreat groove is adapted to the diameter of the first elastic member.

9. The screw insertion depth measuring device according to claim 1, characterized in that: A second elastic member is installed at the bottom of the detection sleeve. The second elastic member is a conical spring and is sleeved outside the rod body. One end of the second elastic member away from the detection sleeve contacts the bearing.

10. The screw insertion depth measuring device according to claim 3, characterized in that: The pressing plate is arranged on one side of the viewing window and does not overlap with the viewing window.

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