Universal articulating center follower

Abstract

The application discloses a universal joint center following device, which is characterized in that a fixed band is fixedly connected to the bottom of a female head structure of a joint upper frame, the fixed ends of a first telescopic guide rod and a second telescopic guide rod are fixedly connected to the female head structure, the telescopic end of the first telescopic guide rod is rotationally connected with a male head structure, the telescopic end of the second telescopic guide rod is installed in a straight slot hole of the male head structure, a joint motor is fixedly connected below the male head structure, a driven plate of a joint lower frame is fixedly connected with the joint motor on the upper surface and with the fixed ends of a third telescopic guide rod and a fourth telescopic guide rod on the lower surface, the telescopic end of the third telescopic guide rod is rotationally connected with a lifting fine adjustment module, the telescopic end of the fourth telescopic guide rod is installed in a straight slot hole of the lifting fine adjustment module, a lifting platform of the lifting fine adjustment module can be adjusted to lift, and a fixed band is fixedly connected to the bottom of the lifting platform. The application can adjust the shape of an exoskeleton, and realizes real-time dynamic matching and alignment of the joint motion center of the exoskeleton and the joint motion center of a human body.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of exoskeleton design and production, and particularly relates to a universal joint motion center following device. BACKGROUND

[0002] The motion of human knee joint mainly shows flexion and extension in the sagittal plane, but due to the existence of ligaments, muscles and other soft tissues, the tibia will produce a sliding phenomenon during rolling along the surface of the femoral end when the knee joint is in motion, which causes the instantaneous rotation center of the knee joint to move constantly in the sagittal plane during the motion. Similarly, the instantaneous rotation center of the human elbow joint will also move during flexion due to the rolling motion between the humerus and the ulna and radius. Most exoskeletons simplify the joints at the knee joint and the elbow joint as single-hinged rotation, and due to the simplification of the joints, the exoskeletons generally cannot realize the migration during the motion. This will cause misalignment between the exoskeleton and the rotation axis of the human upper limb joint. If the exoskeleton does not include all the degrees of freedom existing in the human joint, misalignment is inevitable.

[0003] Some exoskeletons use cam devices to imitate the shape of the femoral end in the knee to fit the relative motion between the tibia and the femur, but since wearers of different body types have different sizes of limbs, it is difficult to design a universal mechanism to realize the sliding surface of different joints such as knees, elbows and hips of different wearers. SUMMARY

[0004] In view of the deficiencies of the prior art, the present application provides a universal joint motion center following device.

[0005] The specific technical solutions are as follows:

[0006] A universal joint motion center following device, comprising an upper joint framework and a lower joint framework;

[0007] The upper joint framework comprises a female head structure, a male head structure, a joint motor, first and second telescopic guide rods which are identical in structure; a fixing belt is fixedly connected to the bottom of the female head structure for fixing the upper joint framework on the limb; the fixed ends of the first and second telescopic guide rods are fixedly connected to the female head structure, the telescopic end of the first telescopic guide rod is rotatably connected to the male head structure, the telescopic end of the second telescopic guide rod is installed in a straight slot hole of the male head structure, and the telescopic end of the second telescopic guide rod can move in the straight slot hole in a limited manner; the joint motor is fixedly connected below the male head structure;

[0008] The lower joint framework comprises: a lifting fine adjustment module, a driven plate, a third telescopic guide rod and a fourth telescopic guide rod which are of the same structure; the upper surface of the driven plate is fixedly connected with the joint motor, the lower surface is fixedly connected with the fixed ends of the third telescopic guide rod and the fourth telescopic guide rod, the telescopic end of the third telescopic guide rod is rotationally connected with the lifting fine adjustment module, the telescopic end of the fourth telescopic guide rod is installed in the straight slot hole of the lifting fine adjustment module, and the telescopic end of the fourth telescopic guide rod can move in the straight slot hole in a limited manner; the lifting platform of the lifting fine adjustment module can be adjusted in height, and the bottom of the lifting platform is fixedly connected with a fixing belt for fixing the lower joint framework on the limb.

[0009] Further, the lifting fine adjustment module comprises: a lifting knob, two half-circular cover plates, a knob bearing, a telescopic sleeve, a lifting platform base, and a lifting platform.

[0010] The lifting platform base is internally provided with a cylindrical cavity, and a guide rail is arranged on the inner wall of the cavity; the telescopic sleeve is a cylinder with a cylindrical through hole at the shaft center, and is arranged in the cavity; a groove is arranged on the outer wall of the telescopic sleeve at a position corresponding to the guide rail, so that the telescopic sleeve can move axially along the guide rail; an internal thread is arranged on the inner wall of the telescopic sleeve; a through hole and a bearing hole are arranged on the top of the lifting platform base, and a through hole is arranged on the bottom, and the through holes on the top and the bottom are in communication with the cavity;

[0011] The knob bearing is embedded in the bearing hole of the lifting platform base in an interference fit, the lower end of the rod of the lifting knob is provided with an external thread, and the upper end is provided with a protrusion; the lifting knob passes through the through hole on the top of the lifting platform base and is in interference fit with the knob bearing, and the protrusion on the lifting knob axially limits the lifting knob and the knob bearing; the two half-circular cover plates are fixed on the upper surface of the lifting platform base and the outer periphery of the rod of the lifting knob; the lifting platform is arranged in the through hole on the bottom of the lifting platform base, the upper part of the lifting platform is fixedly connected with the telescopic sleeve, and the lower part is fixedly connected with the fixing belt.

[0012] Further, a wearing groove is arranged on the bottom of the lifting platform, for allowing the fixing belt to pass through, so as to fix the lower joint framework with the human limb.

[0013] Further, the bottom surface of the female head structure is attached to the surface of the limb, and a wearing groove is arranged on the bottom of the female head structure, for allowing the fixing belt to pass through, so as to fix the upper joint framework with the human limb.

[0014] Further, the female head structure and the male head structure are respectively provided with a hollow structure obtained according to the stress calculation results.

[0015] Further, the female head structure is provided with a through hole for connecting with other exoskeleton components, and the lifting fine adjustment module is provided with a through hole for connecting with other exoskeleton components.

[0016] Further, the lower part of the joint framework further comprises a fixing plate, a positioning groove is formed in the lower surface of the driven plate, the positioning groove is adapted to the size of the lower part of the telescopic guide rod, the fixed ends of the third telescopic guide rod and the fourth telescopic guide rod are arranged in the positioning groove respectively, and the fixed ends are fixed on the driven plate through screws, the fixing plate covers the third telescopic guide rod and the fourth telescopic guide rod, and the fixing plate is fixed on the driven plate, so that the third telescopic guide rod and the fourth telescopic guide rod are fixed.

[0017] Further, the fixed ends of the first telescopic guide rod and the second telescopic guide rod are fixed on the female head structure through screws, and the exposed screws are protected by screw sleeves.

[0018] Further, the telescopic end of the second telescopic guide rod is installed in the straight slot hole of the male head structure through a light axis screw, and the telescopic end of the fourth telescopic guide rod is installed in the straight slot hole of the lifting fine adjustment module through a light axis screw.

[0019] The present application has the following advantages:

[0020] (1) The present application utilizes the interaction force between the human body and the exoskeleton to drive the differentially variable telescopic guide rod on the exoskeleton to adjust the length and angle of the exoskeleton, so as to realize the real-time dynamic matching and alignment of the exoskeleton joint motion center and the human joint motion center, and reduce the compression and obstruction of the exoskeleton to the human upper limbs during movement.

[0021] (2) The present application can adjust the form of the exoskeleton through the differentially variable telescopic guide rod and the lifting fine adjustment module on the exoskeleton according to the size of the limbs of wearers of different body types and different limb parts, so as to reduce the radial force and axial force from the exoskeleton received by the wearer during movement.

[0022] (3) The present application is a universal joint motion center following structure, which can be applied to the elbow, hip, knee and other parts as one of the universal modules of the exoskeleton. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a motion diagram of a wearer wearing an exoskeleton in the prior art, wherein (a) is a case where the wearer drives the exoskeleton to rotate, and (b) is a case where the exoskeleton is fixedly connected with a sleeve of a human limb.

[0024] Figure 2 is a three-dimensional model diagram of a universal joint motion center following device proposed by the present application.

[0025] Figure 3 is a perspective model view of the upper joint skeleton of the universal joint center following device of the present application.

[0026] Figure 4 is an exploded view of the upper joint skeleton of the universal joint center following device of the present application.

[0027] Figure 5 is a female head structure schematic diagram of the upper joint skeleton of the present application, wherein (a) is a bottom view of the female head structure, and (b) is an A-A cross-sectional view of (a).

[0028] Figure 6 is a male head structure schematic diagram of the upper joint skeleton of the present application, wherein (a) is a top view of the male head structure, and (b) is a B-B cross-sectional view of (a).

[0029] Figure 7 is a bottom view perspective model view of the lower joint skeleton of the universal joint center following device of the present application.

[0030] Figure 8 is a bottom view exploded view of the lower joint skeleton of the universal joint center following device of the present application.

[0031] Figure 9 is a structure schematic diagram of the lifting fine-tuning module of the lower joint skeleton of the present application, wherein (a) is a perspective schematic diagram of the lifting fine-tuning module, (b) is an exploded view of the lifting fine-tuning module, (c) is a front view of the lifting fine-tuning module, and (d) is a C-C cross-sectional view of (c).

[0032] Figure 10 is a structure schematic diagram of the lifting platform base of the lifting fine-tuning module of the present application, wherein (a) is a front view of the lifting platform base, (b) is a D-D cross-sectional view of (a), and (c) is an E-E cross-sectional view of (a).

[0033] In the figure, the upper joint skeleton 1, the female head structure 11, the screw hole 11a, the positioning shoulder 11b, the screw sleeve 12, the upper telescopic guide rod 13, the first telescopic guide rod 131, the second telescopic guide rod 132, the male head structure 14, the joint motor 15; the lower joint skeleton 2, the lifting fine-tuning module 21, the lifting knob 211, the knob shaft shoulder 211a, the semicircular cover plate 212, the knob bearing 213, the telescopic sleeve 214, the lifting platform base 215, the bearing hole 215a, the guide rail 215b, the lifting platform 216, the lower telescopic guide rod 22, the third telescopic guide rod 221, the fourth telescopic guide rod 222, the fixed plate 23, the driven plate 24, the positioning groove 24a; the optical axis screw 3, the round hole 4, the straight slot hole 5, the hollow structure 6, the wearing groove 7. DETAILED DESCRIPTION

[0034] The present application will be described in detail below with reference to the accompanying drawings and preferred embodiments, the objects and effects of the present application will become more apparent. It should be understood that the specific embodiments described herein are merely intended to explain the present application and not to limit the present application.

[0035] As shown in Figure 1 , due to the gravity and the characteristics of human physiological structure, there is always a deviation d e between the exoskeleton and the corresponding joint center of human body, whether in static state or in the process of movement. As shown in Figure 1 (a), when the wearer drives the exoskeleton to rotate an angle θ, it will inevitably cause the radial slip d w and the axial slip d l of the fixed position of the exoskeleton and the human body.

[0036] As shown in Figure 1 (b), when the exoskeleton and the human body are fixed in a sleeve manner, due to the different sizes of the limbs of wearers with different body types, and the different thicknesses of the limbs at both ends of each joint, whether it is the elbow, hip or knee, this will cause the rotation axis of the exoskeleton joint and the rotation axis of the human body joint to be non-parallel when the exoskeleton is worn on the human body. If the human body rotates an angle θ, the sleeve and the limb will produce a deviation of γ angle, which will cause the exoskeleton to press the wearer's limb and hinder its normal movement.

[0037] As shown in Figure 2 , a general joint center following device includes an upper joint skeleton 1 and a lower joint skeleton 2, and the connection between the two is a joint.

[0038] As shown in Figures 3-6 , the upper joint skeleton 1 includes a female head structure 11, a screw sleeve 12, an upper telescopic guide rod 13, a male head structure 14, and a joint motor 15. The female head structure 11 is a one-piece structure, the bottom surface of which is a fixed platform surface that contacts the human body. The fixed platform surface is designed to fit the surface of the human muscle. A wearing groove 7 is provided above the fixed platform surface for the fixed band to pass through, so as to fix the upper joint skeleton 1 with the human body. In this embodiment, the fixed band is a magic tape, and the fixed band and the female head structure 11 are fixed by a screw. In actual application, the wearing groove 7 can also be omitted, and the fixed band can be directly fixed with the female head structure 11. Two parallel stepped through holes are provided above the wearing groove 7 of the female head structure 11 for placing and limiting the upper telescopic guide rod 13.

[0039] The upper telescopic guide rod 13 includes a first telescopic guide rod 131 and a second telescopic guide rod 132. The two have the same structure and are respectively arranged in two stepped through holes. The fixed ends of the first telescopic guide rod 131 and the second telescopic guide rod 132 are wider and higher than their telescopic ends. The fixed ends are fixed to the female head structure 11 by screws and screw holes 11a, and the exposed screws are protected by screw sleeves 12. The size of the stepped through holes is adapted to the upper telescopic guide rod 13. Due to the difference in width and height between the telescopic end and the fixed end, there is also a difference in width and height at the junction of the two through holes (i.e., the positioning shoulder 11b), which axially limits the fixed end. The telescopic end of the first telescopic guide rod 131 is connected to the round hole 4 on the male head structure 14 via the optical axis screw 3. The telescopic end of the second telescopic guide rod 132 is connected to the straight slot hole 5 on the male head structure 14 via the optical axis screw 3. The telescopic end of the second telescopic guide rod 132 can move in a restricted manner within the straight slot hole 5. The round hole 4 and the straight slot hole 5 are parallel to each other at the bottom front end of the male head structure 14. The length adjustment of the upper skeleton 1 of the joint is achieved by the synchronous movement of the two upper telescopic guide rods 13, and the shape adjustment of the upper skeleton 1 of the joint is achieved by the differential movement of the two upper telescopic guide rods 13 (i.e., the second telescopic guide rod 132 extends while the first telescopic guide rod 131 remains stationary or shortens). This enables real-time dynamic matching and alignment between the exoskeleton joint motion center and the human joint motion center during the extension and flexion movements of human limb joints.

[0040] The male head structure 14 has a through hole at its top for fixing and mounting the joint motor 16, which is located below the male head structure 14 after installation; the male head structure 14 does not directly contact the human body. When the joint motor 16 operates, the male head structure 14 rotates relative to the female head structure 11. The top of the female head structure 11 can also have a through hole for connecting to other exoskeleton components. Based on stress calculation results, a hollow structure 6 is provided on the female head structure 11 and the male head structure 14 to increase their structural strength while reducing weight.

[0041] like Figure 7 , Figure 8 As shown, the lower joint skeleton 2 includes: a lifting and fine-tuning module 21, a lower telescopic guide rod 22, a fixing plate 23, and a driven plate 24. A circular hole 4 and a straight slot hole 5 are parallel to each other at the front end of the lifting and fine-tuning module 21. The lower telescopic guide rod 22 includes a third telescopic guide rod 221 and a fourth telescopic guide rod 222, both with identical structures. The telescopic end of the third telescopic guide rod 221 is connected to the circular hole 4 on the lifting and fine-tuning module 21 via an optical axis screw 3, and the telescopic end of the fourth telescopic guide rod 222 is connected to the straight slot hole 5 on the lifting and fine-tuning module 21 via an optical axis screw 3. The telescopic end of the fourth telescopic guide rod 222 can perform restricted movement within the straight slot hole 5. A through hole is provided on the lifting and fine-tuning module 21 for connection with other exoskeleton components.

[0042] The upper surface of the driven plate 24 is fixedly connected with the joint motor 16; the lower surface of the driven plate 24 is provided with a positioning groove 24a, which is adapted to the lower telescopic guide rod 22, the fixed ends of the third telescopic guide rod 221 and the fourth telescopic guide rod 222 are arranged in the positioning groove 24a respectively and are fixedly connected with the driven plate 24 through screws, and the fixed plate 23 covers the lower telescopic guide rod 22 and is fixedly connected with the driven plate 24, so as to limit the fixed end of the lower telescopic guide rod 22 in the axial and radial directions. The length adjustment of the joint lower framework 2 is realized through the synchronous movement of the two lower telescopic guide rods 22, and the shape adjustment of the joint lower framework 2 is realized through the differential movement of the two lower telescopic guide rods 22 (i.e. the fourth telescopic guide rod 222 is elongated, and the third telescopic guide rod 221 is not moved or shortened), so as to realize the real-time dynamic matching and alignment of the joint movement center of the exoskeleton and the joint movement center of the human body when the human limb joint is stretched and bent.

[0043] As shown in Figure 9 , Figure 10 , the lifting fine adjustment module 21 comprises a lifting knob 211, two half-circular cover plates 212, a knob bearing 213, a telescopic sleeve 214, a lifting platform base 215 and a lifting platform 216. The lifting platform base 215 has a cylindrical cavity in the inside, and an axial guide rail 215b is arranged on the inner wall of the cavity; the top of the lifting platform base 215 is provided with a through hole and a bearing hole 215a, the through hole at the top is communicated with the cavity, and the bottom is also provided with a through hole, which is also communicated with the cavity.

[0044] The knob bearing 213 is embedded in the bearing hole 215a of the lifting platform base 215 through interference fit. The lower end of the rod of the lifting knob 211 is provided with external threads, and the upper end is provided with a protrusion, which is the knob shaft shoulder 211a. The lifting knob 211 passes through the through hole at the top of the lifting platform base 215 and extends into the telescopic sleeve 214, and the lifting knob 211 is interference-fitted with the knob bearing 213, and the knob shaft shoulder 211a limits the axial position of the lifting knob 211 and the knob bearing 213. The two half-circular cover plates 212 are fixed on the upper surface of the lifting platform base 215 and the outer periphery of the rod of the lifting knob 211, so as to limit the radial position of the lifting knob 211.

[0045] The telescopic sleeve 214 is a cylinder with a cylindrical through hole at the shaft center, arranged in the cavity inside the lifting platform base 215, and the outer wall of the telescopic sleeve 214 is provided with grooves corresponding to the guide rails 215b of the lifting platform base 215; the outer thread of the lifting knob 211 is engaged with the inner thread of the telescopic sleeve 214, and when the lifting knob 211 rotates, the telescopic sleeve 214 moves axially along the guide rails 215b through threaded transmission. The lifting platform 216 is arranged in the through hole at the bottom of the lifting platform base 215, and the bottom of the lifting platform 216 is provided with a wearing groove 7 for allowing the fixing belt to pass through, so as to fix the lower skeleton 2 of the joint with the human limb; in this embodiment, the fixing belt is a magic tape, and the fixing belt and the lifting platform 216 are fixedly connected through a screw; in actual application, the wearing groove 7 can also be not provided, and the fixing belt and the lifting platform 216 are directly fixedly connected. The upper surface of the lifting platform 216 is fixedly connected with the telescopic sleeve 214, so that the lifting platform 216 can move axially with the telescopic sleeve 214, thereby realizing adjustment of the contact distance between the exoskeleton and the human limb.

[0046] The present application provides a universal joint center following device, which uses the interaction force between the wearer and the exoskeleton to drive the exoskeleton to follow the human limb to move. The present application uses the upper telescopic guide rod 13 and the lower telescopic guide rod 22 to change the shape of the exoskeleton during movement, including the length and angle, and in the process of synchronous movement of the exoskeleton and the human limb, when the telescopic guide rod moves synchronously, the length of the exoskeleton skeleton is adjusted to eliminate the movement deviation d l ; when the telescopic guide rod differentially moves, the skeleton rotates to eliminate the deviation γ, thereby realizing the following of the exoskeleton to the joint center of the human limb, and reducing the compression of the exoskeleton to the wearer's limb during movement. The present application adjusts the contact distance between the exoskeleton and the limb through the lifting fine adjustment module 21, so that the rotation plane of the exoskeleton can coincide with the rotation plane of the human limb.

[0047] Those skilled in the art can understand that the above description is only a preferred example of the application and is not used to limit the application, although the application has been described in detail with reference to the foregoing examples, and those skilled in the art can still modify the technical solutions recorded in the foregoing examples or make equivalent replacement for part of the technical features. Any modification, equivalent replacement, etc. made within the spirit and principles of the application shall be included in the protection scope of the application.

Claims

1. A universal center of motion following device, characterized in that, The joint upper skeleton and the joint lower skeleton are included. The joint upper skeleton includes a female head structure, a male head structure, a joint motor, a first telescopic guide rod and a second telescopic guide rod with the same structure. A fixing belt is fixed at the bottom of the female head structure to fix the joint upper skeleton on a limb. The fixed ends of the first telescopic guide rod and the second telescopic guide rod are fixed on the female head structure. The telescopic end of the first telescopic guide rod is rotatably connected with the male head structure. The telescopic end of the second telescopic guide rod is installed in a straight slot hole of the male head structure, and the telescopic end of the second telescopic guide rod can move in the straight slot hole in a limited manner. The joint motor is fixed below the male head structure. The joint lower skeleton includes a lifting fine adjustment module, a driven plate, a third telescopic guide rod and a fourth telescopic guide rod with the same structure. The upper surface of the driven plate is fixed with the joint motor, and the lower surface is fixed with the fixed ends of the third telescopic guide rod and the fourth telescopic guide rod. The telescopic end of the third telescopic guide rod is rotatably connected with the lifting fine adjustment module. The telescopic end of the fourth telescopic guide rod is installed in a straight slot hole of the lifting fine adjustment module, and the telescopic end of the fourth telescopic guide rod can move in the straight slot hole in a limited manner. The lifting platform of the lifting fine adjustment module can be adjusted in height. A fixing belt is fixed at the bottom of the lifting platform to fix the joint lower skeleton on a limb.

2. The universal center-of-motion following device of claim 1, wherein, The lifting fine adjustment module includes a lifting knob, two half-circular cover plates, a knob bearing, a telescopic sleeve, a lifting platform base, and a lifting platform. The lifting platform base is internally provided with a cylindrical cavity. A guide rail is arranged on the inner wall of the cavity. The telescopic sleeve is a cylinder with a cylindrical through hole at the shaft center and is arranged in the cavity. A groove is arranged on the outer wall of the telescopic sleeve at a position corresponding to the guide rail, so that the telescopic sleeve can move axially along the guide rail. An internal thread is arranged on the inner wall of the telescopic sleeve. A through hole and a bearing hole are arranged at the top of the lifting platform base, and a through hole is arranged at the bottom. The through holes at the top and the bottom are in communication with the cavity. The knob bearing is embedded in the bearing hole of the lifting platform base in an interference fit. The lifting knob is provided with an external thread at the lower end of the rod and a protrusion at the upper end. The lifting knob passes through the through hole at the top of the lifting platform base and is in interference fit with the knob bearing. The protrusion on the lifting knob axially limits the lifting knob and the knob bearing. The lifting knob extends into the axial through hole of the telescopic sleeve, and the external thread of the lifting knob is engaged with the internal thread of the telescopic sleeve. The two half-circular cover plates are fixed on the upper surface of the lifting platform base and the outer periphery of the rod of the lifting knob. The lifting platform is arranged in the through hole at the bottom of the lifting platform base. The upper part of the lifting platform is fixed with the telescopic sleeve, and the lower part is fixed with the fixing belt.

3. The universal center-of-motion following device of claim 2, wherein, A wearing groove is arranged at the bottom of the lifting platform to allow the fixing belt to pass through, so that the joint lower skeleton is fixed with the human limb.

4. The universal center-of-motion following device of claim 1, wherein, The bottom surface of the female head structure is attached to the surface of the limb. A wearing groove is arranged at the bottom of the female head structure to allow the fixing belt to pass through, so that the joint upper skeleton is fixed with the human limb.

5. The universal center-of-motion following device of claim 1, wherein, The female head structure and the male head structure are respectively provided with hollow structures obtained according to stress calculation results.

6. The universal center-of-motion following device of claim 1, wherein, The female head structure is provided with a through hole for connecting with other exoskeleton components.

7. The universal center-of-motion following device of claim 1, wherein, The lower part of the joint framework further comprises a fixing plate, a positioning groove is formed on the lower surface of the driven plate, the size of which is adapted to the lower part of the telescopic guide rod, the fixed ends of the third telescopic guide rod and the fourth telescopic guide rod are arranged in the positioning groove respectively, and are fixed on the driven plate through screws, the fixing plate covers the third telescopic guide rod and the fourth telescopic guide rod, and the fixing plate is fixed on the driven plate, thereby fixing the third telescopic guide rod and the fourth telescopic guide rod.

8. The universal center-of-motion following device of claim 1, wherein, The fixed ends of the first telescopic guide rod and the second telescopic guide rod are fixed on the female head structure through screws, and the exposed screws are protected by screw sleeves.

9. The universal center-of-motion following device of claim 1, wherein, The telescopic end of the second telescopic guide rod is installed in the straight slot hole of the male head structure through a light axis screw, and the telescopic end of the fourth telescopic guide rod is installed in the straight slot hole of the lifting fine adjustment module through a light axis screw.

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