Main rod connecting device of external bone fixing frame

Abstract

The invention discloses a main rod connecting device of an external bone fixing frame, and relates to the technical field of medical instruments. Comprising fixing rods, steel needles are installed in the fixing rods, universal joints are installed at the opposite ends of the two fixing rods, a shell is arranged between the two universal joints, a grading rotating mechanism is installed in the shell, an adjusting assembly is installed at the lower end of the front side of the shell, and the grading rotating mechanism comprises a baffle. A rotating rod is rotatably connected to the upper end of the barrier plate, a resistance assembly is installed in a second gear, normal joint movement is simulated, the problem that joints of a patient are stiff in all recovery stages is solved, the patient is helped to rebuild motion perception so as to improve the recovery effect, resistance during limb rotation of the patient can be increased step by step, and the recovery effect is improved. Exercise and adaptability to the limbs of the patient are enhanced, the recovery effect of the fracture area of the patient is improved, and growth of callus is promoted.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, in particular to a main rod connecting device of an external bone fixator. Background Art

[0002] An external fixator is a surgical device used for fracture fixation or limb correction. It uses percutaneously implanted steel pins or screws in the bone and external connecting rods to form a stable framework, achieving fixation of the fracture ends or deformity correction. It is particularly suitable for patients with complex fractures and poor soft tissue conditions. Steel pins are used to fix the two ends of the patient's fracture area, and then connected via a main rod connecting device to maintain the stability of the patient's fracture ends. After the main rod connecting device and steel pins are used to fix the patient's fracture area, long-term fixation can lead to joint stiffness, which needs to be relieved through loosening and rehabilitation training. However, the existing main rod connecting device requires medical staff to open the fixing bolts on the main rod connecting device and assist the patient to move the joints to prevent joint stiffness. On the one hand, this method is not conducive to targeted recovery training based on the patient's recovery condition. On the other hand, it not only increases the workload of medical staff, but may also cause secondary injuries to patients due to poor control of the force.

[0003] In view of the above problems, it is urgent to carry out innovative design based on the main rod connection device of the original external fixator. Summary of the Invention

[0004] The purpose of the present invention is to provide a main rod connection device for an external fixator to solve the problem proposed in the above-mentioned background technology that it is not conducive to targeted recovery training according to the recovery of the patient's condition and the strength control is not good, resulting in secondary injuries to the patient. The technical solution of the present invention addresses the technical problem that the existing technical solution is too single and provides a solution that is significantly different from the existing technology.

[0005] To achieve the above-mentioned object, the present invention provides the following technical solution: a main rod connecting device of an external bone fixator, comprising a fixing rod, a steel pin installed inside the fixing rod, two groups of fixing rods are provided, universal joints are installed at opposite ends of the two groups of fixing rods, a housing is provided between the two groups of universal joints, the bottom end of the rear side of the housing is fixedly connected to the top of the lower universal joint, the top end of the rear side of the housing is rotatably connected to a rotating block, the rotating block is fixedly connected to the upper universal joint, a graded rotating mechanism is installed inside the housing, and an adjustment component is installed at the lower end of the front side of the housing; The graded rotation mechanism includes a baffle plate installed inside the shell, and two groups of baffle plates are provided to divide the internal space of the shell into three independent cavities. The upper end of the baffle plate is rotatably connected to a rotating rod, and the rear end of the rotating rod extends out of the shell and is connected to the rotating block. The front end of the rotating rod passes through the baffle plate and is rotatably connected to the front inner wall of the shell. Three groups of first gears are installed on the surface of the rotating rod corresponding to the three independent cavity positions, and a rotating drum is installed in the area below the first gear inside the shell. A second gear is provided on the surface of the rotating drum corresponding to the first gear, and a resistance component is installed inside the second gear.

[0006] Preferably, the resistance assembly includes a guide ring, one end of which is installed on the inner wall of the bottom end of the cavity inside the shell through a fixed block, and the other end of the guide ring passes through the movable groove at the side end of the second gear and is fixedly connected to the other side of the fixed block. The outer periphery of the guide ring close to the first gear is slidably connected to a slider, and the outer periphery of the guide ring is provided with a first spring.

[0007] Preferably, the adjusting assembly includes a pushing rod, which is limited and slides inside the rotating cylinder, and a first interference block is installed on the surface of one end of the pushing rod located inside the rotating cylinder, and a first interference rod is installed in three independent cavities corresponding to the top end of the rotating cylinder, and the top of the first interference rod extends out of the interior of the rotating cylinder and is fixedly connected to the inner wall of the second gear, and a second spring is sleeved on the outer surface of the first interference rod, and a clamping block is provided at the bottom of the first interference block, and the clamping block slides in the limiting slide groove at the bottom of the first interference block, and a third spring is fixedly connected to the top of the clamping block, and the end of the third spring away from the clamping block is connected to the top of the limiting slide groove.

[0008] Preferably, the first gear and the second gear are provided in three groups corresponding to three independent cavities, the second gear is an elliptical structure, and is arranged as a quarter tooth, a third tooth and a half tooth from front to back, the rotating drum is provided with a three-section structure corresponding to the three independent cavities, and each section is rotatably connected by a bearing, and an annular groove is provided on the inner wall of the bottom end of the rotating drum corresponding to the clamping block, and the arc length of the annular groove corresponds to the arc length of the tooth surface of the second gear.

[0009] Preferably, a protrusion is fixedly connected to one side of the bottom of the first interference rod near the pushing rod, a second interference rod is installed on the top of the inner top of the rotating cylinder corresponding to the protrusion, a sliding block is provided on the top of the second interference rod, the sliding block slides horizontally in the upper limit slide groove on the inner wall of the top of the rotating cylinder, a limiting block is provided on the inner wall of the top of the rotating cylinder corresponding to the sliding block, a fourth spring is horizontally arranged between the sliding block and the limiting block, and a plug-in block is installed on the inner wall of the rotating cylinder close to the rotating part corresponding to the second interference rod.

[0010] Preferably, a sliding groove is provided inside the blocking plate corresponding to the slider, and a ratchet is provided at the bottom of the sliding groove, and a plurality of ratchets are evenly distributed along the bottom of the sliding groove. A moving block is provided on one side of the slider and extends into the sliding groove, and a resistance plate is provided at the front end of the moving block, and the resistance plate and the moving block are connected by a torsion spring, and a first hook block is provided at the end of the resistance plate, and a second hook block is provided at the front and rear ends of the moving block corresponding to the first hook block, and the middle part of the second hook block is connected to the moving block by a torsion spring, and a third resistance rod is fixedly connected to the top of the second hook block on the inner wall at the front end of the sliding groove.

[0011] Preferably, a notch is provided on the second gear away from the first gear, the first spring is configured as an annular structure, and both ends of the first spring are fixedly connected to the surfaces of the slider and the fixed block respectively.

[0012] Preferably, the first interference block is configured as a semi-conical structure with the inclined surface facing the rear side, the end of the clamping block is configured as a sloped structure with the inclined surface facing the rear side, a movable groove is provided on one side of the second gear corresponding to the guide ring, and several of the ratchet teeth are provided with interference teeth corresponding to the rotation angle of the second gear.

[0013] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention is provided with a rotating rod, a first gear, a rotating drum, a second gear, and an adjustment component. According to the recovery of the patient's fracture area, the adjustment component can adjust and control the second gears in three independent cavities to engage with the first gear in stages, thereby achieving rotation of the patient's limb at different angles in the recovery stage. The second gear in the front cavity engages with the first gear, which is suitable for small-angle movement (e.g., 0°-30°) in the early stage of fracture to avoid secondary injury. The second gear in the middle cavity engages with the first gear, which is suitable for expanding the limb angle (e.g., 0°-90°) in the middle stage of recovery. The second gear in the rear cavity engages with the first gear, allowing the limb to move freely in the late stage of recovery (e.g., above 90°), simulating normal joint movement and solving the problem of joint stiffness in various recovery stages of the patient. 2. The present invention is provided with a guide ring, a slider, and a first spring. During each stage of the patient's recovery training, the second gear rotates to compress the first spring, thereby providing appropriate resistance to the patient's limb rotation. The direction of the resistance is opposite to the direction of limb movement, which can simulate the soft tissue tension (such as ligament and tendon resistance) during normal joint movement, helping patients rebuild their movement perception and improving the recovery effect. 3. The present invention is provided with a protrusion, a second interference rod, and an inserting block. The protrusion interferes with the second interference rod and is inserted into the inserting block, thereby achieving rotation of the drum when the second gear of the next stage rotates. The rotation of the second gear then compresses the two first springs, gradually increasing the resistance to rotation of the patient's limb, strengthening the exercise and adaptability of the patient's limb, improving the recovery effect of the patient's fracture area, and promoting the growth of callus. 4. The present invention is provided with a ratchet, a moving block and a resistance plate. When the patient releases force on his limb during recovery training, the second gear rotates rapidly under the action of the first spring. At this time, the resistance plate will quickly get stuck in the ratchet, causing the second gear to stop rotating, thereby effectively preventing the patient from suffering secondary injury to the fracture area under the action of the rebound force of the first spring. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the overall structure of the housing of the present invention; Figure 3 This is a schematic diagram of the internal structure of the housing of the present invention; Figure 4 This is a partially enlarged schematic diagram of structure A of the present invention; Figure 5 It is a side cross-sectional schematic diagram of the rear chamber structure of the housing of the present invention; Figure 6 Schematic side cross-sectional view of the middle chamber structure of the housing of the present invention; Figure 7 It is a side cross-sectional schematic diagram of the rear chamber structure of the housing of the present invention; Figure 8 Schematic diagram of the internal structure of the barrier plate of the present invention; Figure 9 This is a partially enlarged schematic diagram of structure B of the present invention; Figure 10 This is a schematic diagram of the overall structure of the gear set inside the housing of the present invention; Figure 11 This is a schematic diagram of the push rod structure of the present invention; Figure 12 This is a schematic cross-sectional view of the regulating assembly structure of the present invention; Figure 13 It is a partially enlarged schematic diagram of the C structure of the present invention.

[0015] In the figure: 1. Fixed rod; 2. Steel needle; 3. Universal joint; 4. Housing; 5. Rotating block; 61. Blocking plate; 62. Rotating rod; 63. First gear; 64. Rotating drum; 65. Second gear; 661. Guide ring; 662. Slider; 663. First spring; 71. Push rod; 72. First interference block; 73. First interference rod; 74. Second spring; 75. Clamping block; 8. Annular groove; 9. Protrusion; 10. Second interference rod; 11. Plug-in block; 12. Ratchet; 13. Moving block; 14. Interference plate; 15. First hook block; 16. Second hook block; 17. Third interference rod. DETAILED DESCRIPTION

[0016] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0017] See also Figures 1-13 The present invention provides a technical solution: a main rod connecting device of an external bone fixator, comprising a fixing rod 1, a steel pin 2 is installed inside the fixing rod 1, two groups of fixing rods 1 are provided, universal joints 3 are installed at opposite ends of the two groups of fixing rods 1, a shell 4 is provided between the two groups of universal joints 3, the bottom end of the rear side of the shell 4 is fixedly connected to the top of the lower universal joint 3, the top end of the rear side of the shell 4 is rotatably connected to a rotating block 5, the rotating block 5 is fixedly connected to the upper universal joint 3, a graded rotating mechanism is installed inside the shell 4, and an adjustment component is installed at the lower end of the front side of the shell 4; The graded rotation mechanism includes a baffle plate 61 installed inside the shell 4. Two groups of baffle plates 61 are provided to divide the internal space of the shell 4 into three independent cavities. The upper end of the baffle plate 61 is rotatably connected to a rotating rod 62. The rear end of the rotating rod 62 extends out of the shell 4 and is connected to the rotating block 5. The front end of the rotating rod 62 passes through the baffle plate 61 and is rotatably connected to the front inner wall of the shell 4. Three groups of first gears 63 are installed on the surface of the rotating rod 62 corresponding to the three independent cavity positions. A rotating drum 64 is installed in the area below the first gear 63 inside the shell 4. The rotating drum 64 is set to a three-section structure corresponding to the three independent cavities, and each section is rotatably connected by a bearing. The surface of the rotating drum 64 is provided with a second gear corresponding to the first gear 63. 65. A resistance component is installed inside the second gear 65. Three groups of first gear 63 and second gear 65 are provided corresponding to three independent cavities. The second gear 65 has an elliptical structure and is arranged as a quarter tooth, a third tooth and a half tooth from front to back. An annular groove 8 is provided on the inner wall of the bottom end of the rotating cylinder 64 corresponding to the clamping block 75. The arc length of the annular groove 8 corresponds to the arc length of the tooth surface of the second gear 65. A notch is provided in the second gear 65 away from the first gear 63 for the second gear 65 to move upward. Since the second gear 65 has an elliptical structure, the first gear 63 and the second gear 65 always remain in meshing state during rotation, and the tooth surface of the second gear 65 is adapted to the tooth surface of the first gear 63.

[0018] As an embodiment of the present invention, the resistance assembly includes a guide ring 661, one end of the guide ring 661 is installed on the inner wall of the bottom end of the internal cavity of the shell 4 through a fixed block, and the other end of the guide ring 661 passes through the movable groove at the side end of the second gear 65 and is fixedly connected to the other side of the fixed block. The outer periphery of the guide ring 661 close to the first gear 63 is slidably connected with a slider 662, and the outer periphery of the guide ring 661 is provided with a first spring 663, which is set to an annular structure. The two ends of the first spring 663 are respectively fixedly connected to the surface of the slider 662 and the fixed block. A movable groove is opened on one side of the second gear 65 corresponding to the guide ring 661. The patient rotates the limb to drive the rotating block 5 to rotate, and the rotation of the rotating block 5 drives the rotating rod 62 to rotate. The rotation of the rotating rod 62 drives the first gear 63 to rotate. The rotation of the first gear 63 drives the second gear 65 to rotate. The rotation of the second gear 65 drives the slider 662 to move along the guide ring 661, thereby squeezing the first spring 663 to generate resistance.

[0019] As an embodiment of the present invention, the adjustment component includes a push rod 71, which is limited and slides inside the rotating cylinder 64. A first interference block 72 is installed on the surface of one end of the push rod 71 located inside the rotating cylinder 64. A first interference rod 73 is installed in three independent cavities corresponding to the top of the internal top of the rotating cylinder 64. The top of the first interference rod 73 extends out of the interior of the rotating cylinder 64 and is fixedly connected to the inner wall of the second gear 65. A second spring 74 is sleeved on the outer surface of the first interference rod 73. A clamping block 75 is provided at the bottom of the first interference block 72. The clamping block 75 slides on the bottom of the first interference block 72 The first engaging groove 74 is provided with a third spring fixedly connected to the top of the clamping block 75, and the end of the third spring away from the clamping block 75 is connected to the top of the limiting slide groove. The first interference block 72 is provided with a semi-circular cone structure with the inclined surface facing the rear side, and the end of the clamping block 75 is provided with an inclined surface structure with the inclined surface facing the rear side. The first interference block 72 is pushed into the rotating drum 64 by the pushing rod 71 to interfere with the first interference rod 73, so that the first interference rod 73 moves upward. The first interference rod 73 moves upward to push the second gear 65 in the front chamber of the shell 4 to engage with its corresponding first gear 63.

[0020] As an embodiment of the present invention, a protrusion 9 is fixedly connected to the side of the bottom of the first interference rod 73 near the push rod 71, and a second interference rod 10 is installed at the top of the inner top of the rotating cylinder 64 corresponding to the protrusion 9. A sliding block is provided on the top of the second interference rod 10, and the sliding block slides horizontally in the upper limit slide groove on the inner wall of the top of the rotating cylinder 64. A limiting block is provided on the inner wall of the top of the rotating cylinder 64 corresponding to the sliding block, and a fourth spring is provided horizontally between the sliding block and the limiting block. A plug-in block 11 is installed on the inner wall of the rotating cylinder 64 near the rotating part corresponding to the second interference rod 10. The first interference rod 73 moves upward and drives the protrusion 9 to interfere with the second interference rod 10 at the same time, so that the second interference rod 10 is inserted into the plug-in block 11.

[0021] As an embodiment of the present invention, a sliding groove is provided inside the blocking plate 61 corresponding to the slider 662, and a ratchet 12 is provided at the bottom of the sliding groove. Several ratchets 12 are evenly distributed along the bottom of the sliding groove, and three groups of ratchets 12 are provided corresponding to three independent cavities. A moving block 13 is provided on one side of the slider 662 and extends into the sliding groove. A resistance plate 14 is provided at the front end of the moving block 13. The resistance plate 14 and the moving block 13 are connected by a torsion spring, and a first hook block 15 is provided at the end of the resistance plate 14. A second hook block 16 is provided at the front and rear ends of the moving block 13 corresponding to the first hook block 15. The middle part of the second hook block 16 is connected to the moving block 13 by a torsion spring, and a third resistance rod 17 is fixedly connected to the top of the second hook block 16 on the inner wall at the front end of the sliding groove. Several ratchets 12 are provided with resistance teeth corresponding to the rotation arc length of the second gear 65. When the patient performs recovery training to release force on his limbs, When the second gear 65 is rotated back rapidly under the action of the first spring 663, the contact plate 14 will be quickly stuck in the ratchet 12, causing the second gear 65 to stop rotating to prevent the patient from causing secondary injury to the fracture area under the action of the rebound force of the first spring 663. When reduction is required, the medical staff will slowly rotate the patient's limb until it is rotated to the corresponding angle. The corresponding large contact tooth will interfere with the contact plate 14, causing the contact plate 14 to rotate upward. The upward rotation of the contact plate 14 drives the first hook block 15 to move upward. The first hook block 15 moves upward so that it is engaged with the second hook block 16 on the moving block 13, and then the patient's limb is slowly straightened. At this time, the third contact rod 17 on the inner wall of the front end of the sliding groove will interfere with the upper end of the second hook block 16, causing the second hook block 16 to deflect, allowing the first hook block 15 to disengage from the second hook block 16, and then reset.

[0022] Working principle: When using the main rod connecting device of this external fixator, the patient's fracture area is first fixed by the steel needle 2 and the fixing plate. When the patient needs recovery training in the early stage of recovery, the first interference block 72 is pushed into the rotating cylinder 64 by the pushing rod 71 to interfere with the first interference rod 73, so that the first interference rod 73 moves upward. The first interference rod 73 moves upward to push the second gear 65 in the front chamber of the shell 4 to engage with its corresponding first gear 63. Since the second gear 65 is an elliptical structure, the first gear 63 and the second gear 65 always maintain an engaged state when rotating. When the first interference block 72 interferes with the first interference rod 73, the clamping block 75 at the bottom of the first interference block 72 will be stuck on the inner wall of the bottom end of the rotating cylinder 64 The annular groove 8 of the housing 4 is shown in FIG. 1 . At this time, the patient rotates his limb to drive the rotating block 5 to rotate, and the rotating block 5 rotates to drive the rotating rod 62 to rotate. The rotating rod 62 rotates to drive the first gear 63 to rotate. The first gear 63 rotates to drive the second gear 65 to rotate. The second gear 65 rotates to drive the slider 662 to move along the guide ring 661, thereby squeezing the first spring 663 to generate resistance. When the second gear 65 rotates, it also drives the rotating drum 64 in the front chamber to rotate, while the first contact rod 73 does not rotate, so that the clamping block 75 moves along the inside of the annular groove 8. At the same time, since the second gear 65 in the front chamber of the housing 4 has only a quarter tooth to match the corresponding annular groove 8, the patient's limb can only rotate 0° to 30°, thereby meeting the patient's initial recovery training requirements. When the patient needs to resume training in the middle stage of recovery, he continues to push the pushing rod 71 to move into the rotating cylinder 64, thereby pushing the first interference block 72 in the middle chamber area to interfere with the first interference rod 73 and move upward, and the corresponding first gear 63 and second gear 65 in the middle chamber are meshed, and the clamping block 75 at the bottom of the first interference block 72 will be stuck in the corresponding annular groove 8 on the inner wall of the bottom end of the rotating cylinder 64. The first interference rod 73 moves upward and drives the protrusion 9 to interfere with the second interference rod 10, so that the second interference rod 10 is inserted into the plug-in block 11. At this time, the patient rotates his limb to drive the rotating block 5 to rotate, and the rotating block 5 rotates to drive the rotating rod 62 to rotate. The rotating rod 62 rotates to drive the first gear 63 to rotate, and the first gear 63 rotates to drive the second gear 65 to rotate. Since the second interference rod 10 is inserted into the plug-in block 11, it will also drive the rotating cylinder 64 in the front chamber to rotate, so that the second gears 65 in the two chambers rotate, and at the same time drive The slider 662 moves along the guide ring 661, squeezing the two sets of first springs 663, thereby increasing the resistance to the rotation of the patient's limbs. At the same time, since the second gear 65 in the middle chamber of the shell 4 has only one-third of the teeth matching the corresponding annular groove 8, the patient's limbs can only rotate 0° to 90°. When the recovery is in the late stage, the push rod 71 continues to be pushed to move into the rotating cylinder 64, thereby pushing the first interference block 72 in the rear chamber area to interfere with the first interference rod 73 and move upward, and then repeat the above operation to further increase the resistance to the rotation of the limbs. At the same time, since the second gear 65 in the middle chamber of the shell 4 has only one-half of the teeth matching the corresponding annular groove 8, the patient's limbs can move freely (such as more than 90°). When the push rod 71 needs to be reset, it can continue to be pushed forward until the clamping block 75 is disengaged from the annular groove 8 on the rear side of the rotating cylinder 64, and then the push rod 71 is rotated 180° and pulled outward, and finally locked and fixed; When the patient releases force on his limb during recovery training, the second gear 65 rotates back rapidly under the action of the first spring 663. At this time, the contact plate 14 will quickly engage with the ratchet 12, causing the second gear 65 to stop rotating to prevent the patient from causing secondary injury to the fracture area under the action of the rebound force of the first spring 663. When reduction is required, the medical staff will slowly rotate the patient's limb until it is rotated to the corresponding angle. The corresponding large contact tooth will interfere with the contact plate 14, causing the contact plate 14 to rotate upward. The upward rotation of the contact plate 14 drives the first hook block 15 to move upward. The first hook block 15 moves upward so that it is engaged with the second hook block 16 on the moving block 13, and then the patient's limb is slowly straightened. At this time, the third contact rod 17 on the inner wall of the front end of the sliding groove will interfere with the upper end of the second hook block 16, causing the second hook block 16 to deflect, allowing the first hook block 15 to disengage from the second hook block 16, and then reduce the position.

[0023] Any content not described in detail in this specification is prior art known to those skilled in the art. In the description of the present invention, unless otherwise specified, "plurality" means two or more. Terms such as "upper," "lower," "left," "right," "inner," "outer," "front," "rear," "head," and "tail" indicate positions or relationships based on those shown in the accompanying drawings and are intended solely for ease of description and simplification. They do not indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation and are therefore not to be construed as limiting the present invention. Furthermore, terms such as "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. In the description of the present invention, unless otherwise specified or limited, the terms "connected" and "connected" are to be understood broadly, meaning, for example, fixedly connected, detachably connected, or integrally connected; mechanically connected, electrically connected; directly connected, or indirectly connected through an intermediary. Those skilled in the art will understand the specific meanings of these terms in the present invention on a case-by-case basis.

[0024] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A main rod connecting device for an external fixator, comprising a fixing rod (1), characterized in that: A steel needle (2) is installed inside the fixing rod (1), and the fixing rod (1) is provided with two groups. Universal joints (3) are installed at opposite ends of the two groups of fixing rods (1). A shell (4) is provided between the two groups of universal joints (3). The bottom end of the rear side of the shell (4) is fixedly connected to the top of the lower universal joint (3). The top end of the rear side of the shell (4) is rotatably connected to a rotating block (5). The rotating block (5) is fixedly connected to the upper universal joint (3). A graded rotating mechanism is installed inside the shell (4), and an adjustment component is installed at the lower end of the front side of the shell (4); The graded rotation mechanism comprises a baffle plate (61) mounted inside the shell (4), wherein two groups of baffle plates (61) are provided, dividing the internal space of the shell (4) into three independent cavities, the upper end of the baffle plate (61) is rotatably connected to a rotating rod (62), the rear end of the rotating rod (62) extends out of the shell (4) and is connected to the rotating block (5), the front end of the rotating rod (62) passes through the baffle plate (61) and is rotatably connected to the front inner wall of the shell (4), three groups of first gears (63) are mounted on the surface of the rotating rod (62) corresponding to the three independent cavity positions, a rotating drum (64) is mounted in the area below the first gear (63) inside the shell (4), a second gear (65) is provided on the surface of the rotating drum (64) corresponding to the first gear (63), and a resistance component is mounted inside the second gear (65).

2. The main rod connecting device of an external fixator according to claim 1, characterized in that: The resistance assembly includes a guide ring (661), one end of which is mounted on the inner wall of the bottom end of the internal cavity of the housing (4) through a fixed block, and the other end of the guide ring (661) passes through a movable groove at the side end of the second gear (65) and is fixedly connected to the other side of the fixed block. A slider (662) is slidably connected to the outer periphery of one end of the guide ring (661) close to the first gear (63), and a first spring (663) is provided on the outer periphery of the guide ring (661).

3. The main rod connecting device of the external fixator according to claim 2, characterized in that: The adjustment component includes a push rod (71), which is limited and slides inside the rotating cylinder (64). A first resistance block (72) is installed on the surface of one end of the push rod (71) located inside the rotating cylinder (64). The top of the rotating cylinder (64) is provided with three independent cavities corresponding to the first resistance rod (73). The top of the first resistance rod (73) extends out of the rotating cylinder (64) and is fixedly connected to the inner wall of the second gear (65). A second spring (74) is sleeved on the outer surface of the first resistance rod (73). A clamping block (75) is provided at the bottom of the first resistance block (72). The clamping block (75) slides in the limiting sliding groove at the bottom of the first resistance block (72). A third spring is fixedly connected to the top of the clamping block (75). The end of the third spring away from the clamping block (75) is connected to the top of the limiting sliding groove.

4. The main rod connecting device of the external fixator according to claim 3, characterized in that: The first gear (63) and the second gear (65) are provided with three groups corresponding to the three independent cavities. The second gear (65) has an elliptical structure and is provided with a quarter tooth, a third tooth and a half tooth from front to back. The rotating drum (64) is provided with a three-section structure corresponding to the three independent cavities, and each section is rotatably connected by a bearing. An annular groove (8) is provided on the inner wall of the bottom end of the rotating drum (64) corresponding to the clamping block (75). The arc length of the annular groove (8) corresponds to the arc length of the tooth surface of the second gear (65).

5. The main rod connecting device of the external fixator according to claim 4, characterized in that: A protrusion (9) is fixedly connected to one side of the bottom of the first resistance rod (73) near the push rod (71), and a second resistance rod (10) is installed at the top end of the rotating cylinder (64) corresponding to the protrusion (9). A sliding block is provided on the top of the second resistance rod (10), and the sliding block slides horizontally in the upper limit slide groove on the inner wall of the top end of the rotating cylinder (64). A limit block is provided on the inner wall of the top end of the rotating cylinder (64) corresponding to the sliding block, and a fourth spring is provided horizontally between the sliding block and the limit block. A plug-in block (11) is installed on the inner wall of the rotating cylinder (64) near the rotating part corresponding to the second resistance rod (10).

6. The main rod connecting device of the external fixator according to claim 5, characterized in that: A sliding groove is provided inside the blocking plate (61) corresponding to the slider (662), and a ratchet (12) is provided at the bottom of the sliding groove. A plurality of ratchet teeth (12) are evenly distributed along the bottom of the sliding groove. A moving block (13) is provided on one side of the slider (662) and extends into the sliding groove. A resistance plate (14) is provided at the front end of the moving block (13). The resistance plate (14) and the moving block (13) are connected by a torsion spring. A first hook block (15) is provided at the end of the resistance plate (14). A second hook block (16) is provided at the front and rear ends of the moving block (13) corresponding to the first hook block (15). The middle of the second hook block (16) is connected to the moving block (13) by a torsion spring. A third resistance rod (17) is fixedly connected to the top of the second hook block (16) on the inner wall of the front end of the sliding groove.

7. The main rod connecting device of an external fixator according to claim 6, characterized in that: The second gear (65) is provided with a notch away from the first gear (63). The first spring (663) is configured as a ring structure. Both ends of the first spring (663) are fixedly connected to the surfaces of the slider (662) and the fixed block, respectively.

8. The main rod connecting device of the external fixator according to claim 7, characterized in that: The first contact block (72) is configured as a semi-circular table structure with an inclined surface facing the rear side, the end of the clamping block (75) is configured as an inclined surface structure with an inclined surface facing the rear side, a movable groove is provided on one side of the second gear (65) corresponding to the guide ring (661), and a plurality of the ratchet teeth (12) are provided with contact teeth corresponding to the rotation angle of the second gear (65).

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