Well drilling spring strength detection device

Abstract

The invention provides a drilling spring strength detection device, and relates to the technical field of mechanical engineering detection, the drilling spring strength detection device comprises a support main body, a group of support legs are arranged at corners of the bottom of the support main body, one side of the support main body is provided with a stabilizing hole, and the stabilizing hole is of a cylindrical step structure; a pressure detection sensor is installed on the inner side of the stabilizing hole, a positioning disc is installed above the pressure detection sensor, and a rotationally-connected two-way threaded rod is installed above the supporting body. The device solves the problems of poor compatibility, low precision and difficult maintenance of a traditional detection device through the structural design of self-adaptive clamping, dual-mode pressure applying, intelligent correction and quick release maintenance, and the modular integrated design of the device not only meets the diversified detection requirements of the petroleum drilling spring, but also improves the detection precision of the petroleum drilling spring. And the detection efficiency and the reliability are improved through mechanical structure innovation, and the device has remarkable technical advantages in the scenes of oil field equipment manufacturing, field maintenance and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of mechanical engineering detection, and particularly relates to a drilling spring strength detection device. BACKGROUND

[0002] In oil drilling operations, springs are widely used as key components in drilling tool shock absorbers, blowout preventers, safety valves and other equipment. The strength and reliability of the spring directly affect the working performance and service life of the drilling equipment, and even relate to the safety of the entire drilling operation. The patent with the application number 201810049026 discloses a large hook spring elasticity detection device. The patent uses hydraulic control to apply stable and accurate load. However, the comparative document and the existing spring strength detection technology have the following problems: The existing device generally uses manual screw loading or single direction pressure application. The traditional detection device lacks effective spring anti-ejection design. When the spring is overloaded and broken, the flying parts may cause equipment damage or personal injury. When detecting high stiffness springs, the measurement error caused by eccentric loading; Most detection sensors use bolts to secure the installation position. When the spring vibrates during detection, the detection data may deviate due to loose bolts. In addition, since the sizes of springs are different, manual correction is required when detecting different springs. In addition, the patent is mainly for large hook springs, and the application range is narrow. It can only detect spring elasticity and cannot detect compression and tensile strength at the same time, which has great functional limitations. SUMMARY

[0003] The present application relates to a drilling spring strength detection device. The clamping block moves synchronously and reversely along the T-shaped sliding groove until the clamping block clamps the spring. The first electric motor is controlled to move the protective rod downward to form a protective barrier. The effort-saving drive is controlled to drive the pressing plate to press downward at a set rate. The pressure detection sensor collects the F value. After the bottom of the pressing plate contacts the upper part of the detection spring, the movement of the pressing plate is stopped. The second electric motor is controlled to drive the correction block to move, so that the correction block and the position sensor are aligned. At this time, the position sensor is corrected to record the initial position.

[0004] The application provides a kind of drilling spring strength detection device, specifically includes: support main body, a group of support legs is equipped in the bottom position of support main body at corner, a stable hole is opened in one side of support main body, stable hole is cylindrical ladder structure, a pressure detection sensor is installed in the inside position of stable hole, a positioning disc is installed in the position above pressure detection sensor, a rotatingly connected bidirectional threaded rod is installed in the position above support main body, a labor-saving driver is installed in the position above support main body, a group of bolt mounting holes is opened in the bottom position of labor-saving driver, a positioning frame, a position sensor are installed in the position above pressing plate, a stable hole is opened in one side of pressing plate, a first electric motor is installed in the inside of stable hole, a vertical sliding hole is opened in the middle position of pressing plate, a protection rod is inserted in the inside of sliding hole, a second electric motor is installed in the bottom position of support main body, a locking frame is installed in one side of position sensor.

[0005] Further, the bottom position of the positioning disc is opened to an interface groove, the upper position of the pressure detection sensor extends to the inside of the interface groove, the upper position of the positioning disc is opened to a sliding groove, the sliding groove is T-shaped structure, two symmetrically distributed clamping blocks are installed in the inside position of the sliding groove.

[0006] Further, the bottom position of the clamping block is opened to a threaded hole respectively, the spiral of two threaded holes is opposite, the bidirectional threaded rod passes through the inside of threaded hole, under the cooperation of opposite thread, when rotating bidirectional threaded rod, it can control two clamping blocks to move synchronously in opposite direction, bidirectional threaded rod and clamping block cooperatively constitute clamping mechanism.

[0007] Further, one side of the pressing plate is provided with a positioning plate, the positioning plate is rectangular strip structure, one side of the support main body is opened to a sliding hole corresponding to the positioning plate, the positioning plate passes through the inside of the sliding hole, a first rack is installed in one side of the positioning plate, a drive gear is installed in the outside position of the drive shaft of the labor-saving driver, the drive gear is engaged with the first rack, the labor-saving driver, the pressing plate and the first rack cooperatively constitute pressure applying mechanism.

[0008] Further, the positioning plate of the pressing plate is opened to a sliding groove in one side, one side of the bidirectional threaded rod extends to the inside of the sliding groove.

[0009] Further, a first locking rod is installed in the inside position of the positioning frame, a supporting spring is installed in the outside position of the first locking rod, a positioning block is installed in the outside position of the drive shaft of the first electric motor, a plurality of clamping grooves are opened in the edge position of the positioning block in ring array shape, one side of the first locking rod extends to the inside of the clamping groove, a hanging groove is opened in the bottom position of the protection rod, a hanging hole is opened in the upper position of the clamping block.

[0010] Further, one hinged hook is mounted on one side of the first locking rod, and a corresponding ring is mounted on the upper position of the pressing plate.

[0011] Further, a driving gear is mounted on the outer position of the driving shaft of the first electric motor, a positioning groove is formed on one side of the protection rod, a second rack is mounted on the inner position of the positioning groove, and the driving gear and the second rack are engaged.

[0012] Further, a stable plate is arranged on the upper position of the pressing plate, a plurality of bolt mounting holes are formed in the corners of the stable plate, a plurality of mounting blocks are arranged on one side of the position sensor, the mounting blocks pass through the inside of the mounting holes, an annular groove is formed in one side of the mounting block, a locking groove is formed in the corner of the locking frame, and the locking groove and the annular groove of the mounting block correspond.

[0013] Further, a vertical positioning track is arranged on one side of the support body, a rotatingly connected one-way threaded rod is mounted on the inner position of the positioning track, the bottom of the one-way threaded rod is connected with the driving shaft of the second electric motor, a cross-shaped sliding groove is formed in the inner position of the positioning track, a correction block is mounted on the inner position of the sliding groove, a threaded hole is formed in the middle position of the correction block, the one-way threaded rod passes through the inside of the threaded hole, the one-way threaded rod and the threaded hole are threadedly connected, and the second electric motor, the one-way threaded rod and the correction block cooperatively constitute a correction mechanism.

[0014] The drilling spring strength detection device has the following beneficial effects: In the drilling spring strength detection device, the two clamping blocks are synchronously and reversely moved by the reverse thread design when the bidirectional threaded rod rotates, and the clamping blocks clamp the drilling spring.

[0015] The pressure detection sensor monitors the force change of the spring in the compression or stretching process in real time, converts the mechanical signal into an electric signal, and transmits the electric signal to the controller. The position sensor accurately measures the deformation amount of the spring by detecting the position change of the correction block, and calculates the spring stiffness, elastic modulus and other parameters in combination with the pressure data.

[0016] The position sensor is quickly disassembled through the clamping groove and the annular groove of the locking frame, replaces the traditional bolt fixing, greatly shortens the maintenance time, avoids the detection data deviation caused by the bolt loosening, and improves the accuracy of the spring detection.

[0017] The protection rod forms a ring-shaped barrier after descending, prevents the spring from popping out due to overload bending in the spring detection process, and cooperates with the overload protection of the pressure detection sensor to reduce the equipment failure risk.

[0018] The sliding groove of the clamping block cooperates with the limiting function of the bidirectional threaded rod, and the sliding groove of the pressing plate is positioned to prevent components from falling off during the pressure application process, ensuring a safe and reliable detection process.

[0019] The controller centrally manages the pressure detection sensor, dual electric motors and position sensor to automate the entire process from clamping to data output, reducing errors caused by manual intervention.

[0020] This device solves the problems of poor compatibility, low precision and difficult maintenance of traditional detection devices through its structural design of adaptive clamping, dual-mode pressure application, intelligent correction, and quick-disassembly maintenance. Its modular integrated design not only meets the diverse detection needs of oil drilling springs, but also achieves a dual improvement in detection efficiency and reliability through mechanical structure innovation. It has significant technical advantages in scenarios such as oilfield equipment manufacturing and on-site maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings of the embodiments are briefly introduced below.

[0022] The drawings described below only relate to some embodiments of the present invention, but are not intended to limit the present invention.

[0023] In the attached figure: Figure 1 A schematic diagram of the shaft side structure during the spring detection process of the present invention is shown; Figure 2 The present invention shows Figure 1 Schematic diagram of the rear view structure; Figure 3 The present invention shows Figure 1 Schematic diagram of the axle side structure from a rear perspective; Figure 4 It shows a schematic diagram of the axle side structure after the spring is removed of the present invention; Figure 5 The present invention shows Figure 4 Schematic diagram of the local axial structure; Figure 6 A schematic diagram of the axial structure of a partially cutaway structure of the detection device of the present invention is shown; Figure 7 The present invention shows Figure 6 A schematic diagram of the right-angle perspective structure; Figure 8 A schematic diagram of the axial structure of a further cross-section of the detection device of the present invention is shown; Figure 9 The present invention shows Figure 6 A schematic diagram of the enlarged structure at point A; Figure 10 The present invention shows Figure 8The enlarged structural schematic view of B of the first embodiment.

[0024] List of reference signs 1, support body; 102, positioning track; 2, pressure detection sensor; 3, positioning disc; 4, clamping mechanism; 401, bidirectional threaded rod; 402, clamping block; 5, pressure applying mechanism; 501, labor-saving driver; 502, pressing plate; 503, first rack; 6, positioning frame; 601, first locking rod; 7, first electric motor; 701, positioning block; 8, protection rod; 801, second rack; 9, correction mechanism; 901, second electric motor; 902, unidirectional threaded rod; 903, correction block; 10, position sensor; 11, locking frame. DETAILED DESCRIPTION

[0025] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions of the embodiments of the present application will be described clearly and completely below with reference to the drawings of the embodiments of the present application. Obviously, the described embodiments are a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the described embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without any creative effort belong to the scope of protection of the present application.

[0026] Embodiment one: please refer to Figures 1-10 : The present invention proposes a drilling spring strength detection device, comprising: a supporting body 1, a group of supporting legs are provided at the corners of the bottom position of the supporting body 1, a stabilizing hole is opened on one side of the supporting body 1, the stabilizing hole is a cylindrical stepped structure, a pressure detection sensor 2 is installed at the inner position of the stabilizing hole, the stabilizing hole stabilizes the installation position of the pressure detection sensor 2, the model of the pressure detection sensor 2 is selected according to actual needs, a positioning plate 3 is installed above the pressure detection sensor 2, the pressure detection sensor 2 monitors the pressure of the workpiece above the positioning plate 3 in real time, a rotatably connected bidirectional threaded rod 401 is installed above the supporting body 1, a docking groove is opened at the bottom position of the positioning plate 3, the upper position of the pressure detection sensor 2 extends to the inside of the docking groove, and with the cooperation of the docking groove, the pressure detection sensor 2 is realized. The pressure detection sensor 2 and the positioning plate 3 are quickly assembled. A sliding groove is provided at the upper position of the positioning plate 3. The sliding groove is a T-shaped structure. Two symmetrically distributed clamping blocks 402 are installed at the inner position of the sliding groove. The sliding groove positions the moving position circumference and the upper and lower positions of the clamping blocks 402, so that the clamping blocks 402 can move stably laterally along the trajectory of the sliding groove. A threaded hole is provided at the bottom position of the clamping blocks 402. The spirals of the two threaded holes are opposite. The bidirectional threaded rod 401 passes through the inside of the threaded hole. With the cooperation of the reverse threads, the two clamping blocks 402 can be controlled to move synchronously in opposite directions when the bidirectional threaded rod 401 is rotated. The bidirectional threaded rod 401 and the clamping block 402 cooperate with each other to form a clamping mechanism 4 to clamp and position the drill rod spring, so that the drill rod spring can be stably tested for strength. In this embodiment, a labor-saving driver 501 is installed at the upper position of the support body 1, and a group of bolt mounting holes are provided at the bottom position of the labor-saving driver 501. The bolt mounting holes are provided with matching bolts to stabilize the labor-saving driver 501. A positioning plate is provided on one side of the pressing plate 502. The positioning plate is a rectangular strip structure. A sliding hole corresponding to the positioning plate is provided on one side of the support body 1. The positioning plate passes through the interior of the sliding hole. The positioning plate cooperates with the sliding hole to position the pressing plate 502 circumferentially and laterally, so that the pressing plate 502 can move vertically stably when subjected to force. A first rack 503 is installed on one side of the positioning plate. The labor-saving driver 5 01 is provided with a driving gear at the outer position of the driving shaft, and the driving gear is meshed with the first rack 503, and the labor-saving driver 501, the pressing plate 502 and the first rack 503 cooperate with each other to form a pressure mechanism 5, which controls the labor-saving driver 501 to drive the pressing plate 502 to move up and down to repeatedly press the drilling spring machine, and detects the supporting strength of the spring by setting the number of presses. A sliding groove is provided on one side of the positioning plate of the pressing plate 502, and one side of the bidirectional threaded rod 401 extends to the inside of the sliding groove. The sliding groove cooperates with the bidirectional threaded rod 401 to achieve the effect of moving the pressing plate 502 to position the height, and at the same time prevent the pressing plate 502 from falling off; The upper position of the pressing plate 502 is provided with a positioning frame 6 and a position sensor 10, a stable hole is arranged on one side of the pressing plate 502, a first electric motor 7 is arranged in the stable hole, a first locking rod 601 in sliding connection is arranged at the inner side of the positioning frame 6, the sliding position of the first locking rod 601 is supported and circumferentially positioned by the positioning frame 6, a supporting spring is arranged at the outer side of the first locking rod 601, the supporting spring pushes the first locking rod 601 to reset, a positioning block 701 is arranged at the outer side of the driving shaft of the first electric motor 7, a plurality of clamping grooves in annular array are arranged at the edge of the positioning block 701, one side of the first locking rod 601 extends into the clamping grooves, the first electric motor 7 is quickly locked by the first locking rod 601 in cooperation with the positioning frame 6 and the supporting spring, the driving shaft of the first electric motor 7 is prevented from rotating, a hanging groove is arranged at the bottom of the protection rod 8, a hanging hole is arranged at the upper position of the clamping block 402, when the drilling spring with a drag hook is detected, the drag hooks of the spring are connected to the hanging groove and the hanging hole respectively, and the driving shaft of the first electric motor 7 is controlled to be locked, at this time, the strength of the drilling spring can be detected by controlling the lifting and pressing of the pressing plate 502, a hinged hook is arranged at one side of the first locking rod 601, a corresponding hanging ring is arranged at the upper position of the pressing plate 502, when the hanging ring is positioned on the hook, the first locking rod 601 is reversely stretched and positioned, at this time, the driving shaft of the first electric motor 7 is unlocked; The middle position of the pressing plate 502 is provided with a vertical sliding hole, a protection rod 8 is inserted into the sliding hole, a driving gear is installed on the driving shaft of the first electric motor 7 at the outer position, a positioning groove is formed on one side of the protection rod 8, a second rack 801 is installed at the inner position of the positioning groove, the installation position of the second rack 801 in the positioning groove is positioned by a friction surface, the driving gear is engaged with the second rack 801, the first electric motor 7 is controlled to drive the protection rod 8 to move up and down, the protection rod 8 protects the spring during detection by moving downward, and the bending of the spring during detection is avoided to prevent the spring from appearing, the protection rod 8 is convenient for disassembly and assembly of the drilling spring after moving upward, a second electric motor 901 is installed at the bottom position of the support main body 1, a vertical positioning track 102 is arranged on one side of the support main body 1, a rotatingly connected one-way threaded rod 902 is installed at the inner position of the positioning track 102, the bottom of the one-way threaded rod 902 is connected with the driving shaft of the second electric motor 901, the second electric motor 901 is controlled to drive the one-way threaded rod 902 to rotate, a cross-shaped sliding groove is formed at the inner position of the positioning track 102, a correction block 903 is installed at the inner position of the sliding groove, the positioning track 102 positions the correction block 903, a threaded hole is formed at the middle position of the correction block 903, the one-way threaded rod 902 passes through the inside of the threaded hole, and the one-way threaded rod 902 and the threaded hole are screwed, the second electric motor 901, the one-way threaded rod 902 and the correction block 903 cooperatively form a correction mechanism 9, when the one-way threaded rod 902 rotates, the correction block 903 can be driven to move up and down along the positioning track 102 as a stable trajectory, the position sensor 10 quickly corrects the detection position of the spring of different heights by detecting the position of the correction block 903, and the position sensor 10 judges the detection strength of the spring by detecting the position of the correction block 903. In the embodiment, one locking frame 11 is installed on one side of the position sensor 10, a stable plate is arranged above the pressing plate 502, a group of bolt mounting holes are formed at the corners of the stable plate, a group of mounting blocks are arranged on one side of the position sensor 10, the mounting blocks pass through the inside of the mounting holes, and the stable blocks and the mounting holes are matched to realize the effect that the mounting position of the position sensor 10 is quickly positioned, an annular groove is formed in one side of the mounting block, a locking groove is formed at the corner of the locking frame 11, the locking groove corresponds to the annular groove of the mounting block, the locking frame 11 is matched with the locking groove to quickly lock the mounting position of the position sensor 10, the locking frame 11 is pulled upward to unlock the position sensor 10, and the locking frame 11 is arranged to replace the bolts, which not only avoids loosening of the position sensor 10, but also facilitates disassembly and assembly of the position sensor 10.

[0027] In the embodiment, one locking frame 11 is installed on one side of the position sensor 10, a stable plate is arranged above the pressing plate 502, a group of bolt mounting holes are formed at the corners of the stable plate, a group of mounting blocks are arranged on one side of the position sensor 10, the mounting blocks pass through the inside of the mounting holes, and the stable blocks and the mounting holes are matched to realize the effect that the mounting position of the position sensor 10 is quickly positioned, an annular groove is formed in one side of the mounting block, a locking groove is formed at the corner of the locking frame 11, the locking groove corresponds to the annular groove of the mounting block, the locking frame 11 is matched with the locking groove to quickly lock the mounting position of the position sensor 10, the locking frame 11 is pulled upward to unlock the position sensor 10, and the locking frame 11 is arranged to replace the bolts, which not only avoids loosening of the position sensor 10, but also facilitates disassembly and assembly of the position sensor 10. Figures 1-8As shown, one controller is installed on one side of the support body 1 according to actual needs, and the controller is electrically connected with the pressure detection sensor 2, the first electric motor 7, the second electric motor 901 and the position sensor 10 respectively, so as to control the pressure detection sensor 2, the first electric motor 7, the second electric motor 901 and the position sensor 10 through the controller.

[0028] Working principle of the embodiment: Firstly, the controller automatically calibrates the pressure detection sensor 2 to zero, the drilling spring is vertically placed on the positioning disc 3, the bidirectional threaded rod 401 is driven to rotate, the clamping block 402 moves reversely along the T-shaped sliding groove synchronously until the clamping block 402 clamps the spring, the first electric motor 7 is controlled to move the protective rod 8 downward to form a protective barrier, the labor-saving driver 501 is controlled to drive the pressing plate 502 to press downward at a set rate, the pressure detection sensor 2 collects F value, and after the bottom of the pressing plate 502 contacts the upper side of the detection spring, the movement of the pressing plate 502 is stopped, the second electric motor 901 is controlled to drive the correction block 903 to move, so that the correction block 903 and the position sensor 10 are aligned, and the initial position of the position sensor 10 is recorded at this time; The pressing plate 502 is automatically reset to the initial position, the protective rod 8 moves upward to release the operation space, the moving clamping block 402 releases the clamping of the spring, and the spring is taken out. Through the above working principle and operation steps, the device realizes the automation, intelligence and high precision of the drilling spring strength detection, and greatly improves the detection efficiency and data reliability. Through the above working principle and operation steps, the device realizes the automation, intelligence and high precision of the drilling spring strength detection, and greatly improves the detection efficiency and data reliability.

Claims

1. A drilling spring strength detection device, comprising: The support body, the positioning plate and the position sensor, the bottom position of the support body is provided with a group of support legs at the corner, a stabilizing hole is opened on one side of the support body, the stabilizing hole is a cylindrical step structure, a pressure detection sensor is installed at the inner side of the stabilizing hole, and a positioning plate is installed above the pressure detection sensor, which is characterized in that a two-way threaded rod with a rotatable connection is installed at the upper position of the support body, a labor-saving driver is installed at the upper position of the support body, a group of bolt mounting holes are opened at the bottom position of the labor-saving driver, a positioning frame and a position sensor are installed at the upper position of the pressing plate, a stabilizing hole is opened on one side of the pressing plate, a first electric motor is installed inside the stabilizing hole, a vertical sliding hole is opened in the middle position of the pressing plate, a protective rod is inserted inside the sliding hole, a second electric motor is installed at the bottom position of the support body, and a locking frame is installed on one side of the position sensor.

2. A drilling spring strength detection device according to claim 1, characterized in that: A docking groove is provided at the bottom position of the positioning plate, and the upper position of the pressure detection sensor extends to the inside of the docking groove. A sliding groove is provided at the upper position of the positioning plate, and two symmetrically distributed clamping blocks are installed on the inner side of the sliding groove. A threaded hole is provided at the bottom position of each clamping block, and the spirals of the two threaded holes are in opposite directions. The bidirectional threaded rod passes through the inside of the threaded hole. With the cooperation of the reverse thread, the two clamping blocks can be controlled to move synchronously in opposite directions when the bidirectional threaded rod is rotated. The bidirectional threaded rod and the clamping block cooperate with each other to form a clamping mechanism.

3. A drilling spring strength detection device according to claim 1, characterized in that: A positioning plate is provided on one side of the pressing plate, and a sliding hole corresponding to the positioning plate is opened on one side of the supporting body. The positioning plate passes through the inside of the sliding hole. A first rack is installed on one side of the positioning plate. A driving gear is installed at the outer position of the driving shaft of the labor-saving driver. The driving gear and the first rack are engaged. The labor-saving driver, the pressing plate and the first rack cooperate with each other to form a pressure mechanism.

4. A drilling spring strength detection device according to claim 1, characterized in that: A sliding groove is provided on one side of the positioning plate of the pressing plate, and one side of the bidirectional threaded rod extends into the interior of the sliding groove.

5. A drilling spring strength detection device according to claim 1, characterized in that: A first locking rod with a sliding connection is installed on the inner side of the positioning frame, a supporting spring is installed on the outer side of the first locking rod, a positioning block is installed on the outer side of the driving shaft of the first electric motor, a group of card slots distributed in a circular array are opened at the edge of the positioning block, one side of the first locking rod extends to the inside of the card slot, a hanging slot is opened at the bottom position of the protective rod, and a hanging hole is opened at the upper position of the clamping block.

6. A drilling spring strength detection device according to claim 1, characterized in that: A hinged hook is installed on one side of the first locking rod, and a hanging ring corresponding to the hook is installed above the pressing plate.

7. A drilling spring strength detection device according to claim 1, characterized in that: A driving gear is installed at the outer position of the driving shaft of the first electric motor, a positioning groove is opened on one side of the protective rod, and a second rack is installed at the inner position of the positioning groove, and the driving gear and the second rack are meshed.

8. The drilling spring strength detection device according to claim 1, characterized in that: A stabilizing plate is provided above the pressing plate, and a group of bolt mounting holes are opened at the corners of the stabilizing plate. A group of mounting blocks are provided on one side of the position sensor. The mounting blocks pass through the interior of the mounting holes. An annular groove is opened on one side of the mounting blocks. A locking groove is opened at each corner of the locking frame, and the locking groove corresponds to the annular groove of the mounting block.

9. A drilling spring strength detection device according to claim 1, characterized in that: A vertical positioning track is provided on one side of the support body, and a rotatably connected one-way threaded rod is installed on the inner side of the positioning track. The bottom of the one-way threaded rod is connected to the drive shaft of the second electric motor. A cross-shaped sliding groove is provided on the inner side of the positioning track, and a correction block is installed on the inner side of the sliding groove. A threaded hole is provided in the middle position of the correction block, and the one-way threaded rod passes through the inside of the threaded hole to thread the one-way threaded rod and the threaded hole. The second electric motor, the one-way threaded rod and the correction block cooperate with each other to form a correction mechanism.

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