A main rod connecting device of an external bone fixation frame

Abstract

The application discloses a main rod connecting device of an external bone fixing frame and relates to the technical field of medical instruments. The main rod connecting device comprises a fixing rod, a steel needle is arranged in the fixing rod, two groups of universal joints are arranged at opposite ends of the fixing rod, a shell is arranged between the two groups of universal joints, a hierarchical rotating mechanism is arranged in the shell, an adjusting assembly is arranged at the lower end of the front side of the shell, the hierarchical rotating mechanism comprises a blocking plate, a rotating rod is rotatably connected to the upper end of the blocking plate, and a resistance assembly is arranged in the second gear. The main rod connecting device can simulate normal joint movement, solve the problem of joint stiffness in each recovery stage of a patient, help the patient to rebuild movement perception, improve the recovery effect, gradually increase the resistance when the patient's limbs rotate, strengthen the exercise and adaptability of the patient's limbs, improve the recovery effect of the fractured area of the patient, and promote the growth of bone callus.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, specifically to a main rod connection device for an external bone fixation frame. Background Technology

[0002] External fixators are surgical instruments used for fracture fixation or limb orthopedics. They consist of steel pins or screws implanted percutaneously into the bone and external connecting rods forming a stable frame to fix the fracture ends or correct deformities. They are particularly suitable for patients with complex fractures and poor soft tissue conditions. The steel pins fix both ends of the fracture area and then connect them through a main rod connecting device to maintain the stability of the fracture ends. After the main rod connecting device and steel pins fix the fracture area, the joint may become stiff due to prolonged fixation, which requires relaxation and rehabilitation training to alleviate the stiffness.

[0003] However, the existing main rod connection device requires medical staff to loosen the fixing bolts on the main rod connection device and assist the patient in moving the joint to prevent joint stiffness. This method is not conducive to targeted rehabilitation training based on the patient's recovery status. On the other hand, it not only increases the workload of medical staff, but may also cause secondary injury to the patient due to poor control of the force.

[0004] To address the aforementioned issues, there is an urgent need for innovative design of the main rod connection device for existing external fixation frames. Summary of the Invention

[0005] The purpose of this invention is to provide a main rod connection device for an external fixator to solve the problems mentioned in the background art, which are not conducive to targeted rehabilitation training based on the patient's recovery condition and are poor in force control, leading to secondary injury to the patient. The technical solution of this invention addresses the problem that the existing technical solutions are too simplistic and provides a solution that is significantly different from the existing technology.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a main rod connection device for an external fixator, comprising a fixing rod, wherein a steel pin is installed inside the fixing rod, and two sets of fixing rods are provided, with universal joints installed at opposite ends of the two sets of fixing rods, and a housing is provided between the two sets of universal joints, wherein the bottom rear end of the housing is fixedly connected to the top of the lower universal joint, and a rotating block is rotatably connected to the top rear end of the housing, the rotating block being fixedly connected to the upper universal joint, a graded rotation mechanism is installed inside the housing, and an adjustment component is installed at the lower front end of the housing;

[0007] The graded rotation mechanism includes two sets of baffle plates installed inside the housing, which divide the internal space of the housing into three independent cavities. A rotating rod is rotatably connected to the upper end of the baffle plate. The rear end of the rotating rod extends out of the housing and is connected to a rotating block. The front end of the rotating rod passes through the baffle plate and is rotatably connected to the inner wall of the front side of the housing. Three sets of first gears are installed on the surface of the rotating rod corresponding to the three independent cavities. A rotating cylinder is installed inside the housing in the area below the first gears. A second gear is installed on the surface of the rotating cylinder corresponding to the first gears. A resistance component is installed inside the second gear.

[0008] Preferably, the resistance component includes a guide ring, one end of which is mounted on the inner wall of the bottom of the cavity inside the housing via a fixing block, and the other end of which passes through the moving groove on the side of the second gear and is fixedly connected to the other side of the fixing block. A slider is slidably connected to the outer periphery of the end of the guide ring near the first gear, and a first spring is sleeved on the outer periphery of the guide ring.

[0009] Preferably, the adjusting assembly includes a push rod that slides within the rotating cylinder. A first abutment block is mounted on the surface of one end of the push rod inside the rotating cylinder. First abutment rods are mounted in three independent cavities at the top of the rotating cylinder. The top of each first abutment rod extends out of the rotating cylinder and is fixedly connected to the inner wall of the second gear. A second spring is sleeved on the outer surface of the first abutment rod. A locking block is provided at the bottom of the first abutment block. The locking block slides within a limiting groove at the bottom of the first abutment block. A third spring is fixedly connected to the top of the locking block. The end of the third spring away from the locking block is connected to the top of the limiting groove.

[0010] Preferably, the first gear and the second gear are provided with three sets of three independent cavities. The second gear has an elliptical structure and is provided with quarter teeth, one-third teeth and half teeth from front to back. The rotating cylinder is provided with a three-section structure corresponding to the three independent cavities, and each section is rotatably connected by bearings. The inner wall of the bottom of the rotating cylinder is provided with an annular groove corresponding to the snap-fit ​​block. The arc length of the annular groove corresponds to the arc length of the tooth surface of the second gear.

[0011] Preferably, a protrusion is fixedly connected to the bottom of the first abutment rod near the push rod, and a second abutment rod is installed at the top of the inner end of the rotating cylinder corresponding to the protrusion. A sliding block is provided at the top of the second abutment rod, and the sliding block slides laterally in the upper limit groove on the inner wall of the top end of the rotating cylinder. A limit block is provided on the inner wall of the top end of the rotating cylinder corresponding to the sliding block, and a fourth spring is arranged laterally between the sliding block and the limit block. A plug-in block is installed on the inner wall of the rotating cylinder near the rotation point corresponding to the second abutment rod.

[0012] Preferably, the barrier plate has a sliding groove corresponding to the slider inside, and ratchet teeth are provided at the bottom of the sliding groove. Several ratchet teeth 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. An abutment plate is provided at the front end of the moving block. The abutment plate and the moving block are connected by a torsion spring. A first hook block is provided at the end of the abutment plate. A second hook block is provided at the rear end of the front side of the moving block corresponding to the first hook block. The middle part of the second hook block is connected to the moving block by a torsion spring. A third abutment rod is fixedly connected to the top of the second hook block on the inner wall of the front end of the sliding groove.

[0013] Preferably, the second gear has a notch at a location away from the first gear, and the first spring is configured as a ring structure, with its two ends fixedly connected to the surfaces of the slider and the fixed block, respectively.

[0014] Preferably, the first abutting block is configured as a semi-circular frustum structure with the inclined surface facing the rear, the end of the snap-fit ​​block is configured as an inclined surface structure with the inclined surface facing the rear, a moving groove is provided on one side of the second gear corresponding to the guide ring, and a plurality of ratchet teeth are provided with abutting teeth corresponding to the rotation angle of the second gear.

[0015] Compared with the prior art, the beneficial effects of the present invention are:

[0016] 1. This invention comprises a rotating rod, a first gear, a rotating cylinder, a second gear, and an adjustment component. Based on the recovery status of the patient's fracture area, the adjustment component controls the graded engagement of the second gear and the first gear within three independent cavities. This allows for rotation of the limb at different angles during the recovery phase. The engagement of the second gear and the first gear in the anterior cavity is suitable for small-angle movements (e.g., 0°-30°) in the early stages of fracture, preventing secondary injury. The engagement of the second gear and the first gear in the middle cavity is suitable for expanding the limb's angle during the mid-recovery phase (e.g., 0°-90°). The engagement of the second gear and the first gear in the posterior cavity allows for free movement of the limb in the later stages of recovery (e.g., above 90°), simulating normal joint movement and solving the problem of joint stiffness at various recovery stages.

[0017] 2. The present invention is provided with a guide ring, a slider and a first spring. During each stage of patient recovery training, the first spring is squeezed by the rotation of the second gear, thereby providing appropriate resistance when the patient performs 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, help the patient rebuild motor perception and improve the recovery effect.

[0018] 3. The present invention is provided with a protrusion, a second abutting rod and a plug-in block. The protrusion abuts against the second abutting rod and inserts it into the plug-in block, thereby driving the rotating drum to rotate when the second gear of the next stage rotates. This causes the second gear to rotate and simultaneously compress the two first springs, gradually increasing the resistance when the patient's limb rotates, strengthening the exercise and adaptability of the patient's limb, improving the recovery effect of the fracture area, and promoting the growth of callus.

[0019] 4. The present invention is equipped with a ratchet, a moving block and a contact plate. When the patient is performing rehabilitation training and releasing the force of the limb, the second gear rotates rapidly under the action of the first spring. At this time, the contact plate will quickly engage with the ratchet, so that the second gear stops rotating, thereby effectively preventing the patient from suffering secondary damage to the fracture area under the action of the rebound force of the first spring. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0021] Figure 2 This is a schematic diagram of the overall structure of the housing of the present invention;

[0022] Figure 3 This is a schematic diagram of the internal structure of the housing of the present invention;

[0023] Figure 4 This is a partially enlarged schematic diagram of structure A of the present invention;

[0024] Figure 5 This is a side cross-sectional view of the rear chamber structure of the housing of the present invention;

[0025] Figure 6 This is a side cross-sectional view of the central chamber structure of the housing of the present invention;

[0026] Figure 7 This is a side cross-sectional view of the rear chamber structure of the housing of the present invention;

[0027] Figure 8 This is a schematic cross-sectional view of the internal structure of the barrier plate of the present invention;

[0028] Figure 9 This is a partially enlarged schematic diagram of structure B of the present invention;

[0029] Figure 10 This is a schematic diagram of the overall structure of the gear set inside the housing of the present invention;

[0030] Figure 11 This is a schematic diagram of the push rod structure of the present invention;

[0031] Figure 12 This is a schematic cross-sectional view of the adjustment component structure of the present invention;

[0032] Figure 13This is a partially enlarged schematic diagram of the C structure of the present invention.

[0033] In the diagram: 1. Fixed rod; 2. Steel needle; 3. Universal joint; 4. Housing; 5. Rotating block; 61. Barrier plate; 62. Rotating rod; 63. First gear; 64. Rotating cylinder; 65. Second gear; 661. Guide ring; 662. Slider; 663. First spring; 71. Push rod; 72. First abutting block; 73. First abutting rod; 74. Second spring; 75. Snap-fit ​​block; 8. Annular groove; 9. Protrusion; 10. Second abutting rod; 11. Insertion block; 12. Ratchet; 13. Moving block; 14. Abutting plate; 15. First hook block; 16. Second hook block; 17. Third abutting rod. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Please see Figures 1-13 The present invention provides a technical solution: a main rod connection device for an external fixation frame, including a fixing rod 1, a steel needle 2 installed inside the fixing rod 1, two sets of fixing rods 1, universal joints 3 installed at opposite ends of the two sets of fixing rods 1, a housing 4 between the two sets of universal joints 3, the rear bottom end of the housing 4 is fixedly connected to the top of the lower universal joint 3, a rotating block 5 is rotatably connected to the rear top end of the housing 4, the rotating block 5 is fixedly connected to the upper universal joint 3, a graded rotation mechanism is installed inside the housing 4, and an adjustment component is installed at the lower front end of the housing 4;

[0036] The graded rotation mechanism includes two sets of baffle plates 61 installed inside the housing 4, dividing the internal space of the housing 4 into three independent cavities. A rotating rod 62 is rotatably connected to the upper end of the baffle plate 61. The rear end of the rotating rod 62 extends out of the housing 4 and connects 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 inner front wall of the housing 4. Three sets of first gears 63 are installed on the surface of the rotating rod 62 corresponding to the three independent cavities. A rotating cylinder 64 is installed inside the housing 4 in the area below the first gears 63. The rotating cylinder 64 is configured as a three-section structure corresponding to the three independent cavities, with each section rotatably connected by bearings. A second gear is provided on the surface of the rotating cylinder 64 corresponding to the first gears 63. 65. The second gear 65 has a resistance component installed inside. The first gear 63 and the second gear 65 are provided with three sets of three independent cavities. The second gear 65 has an elliptical structure and is arranged with quarter teeth, third teeth and half teeth from front to back. The inner wall of the bottom end of the rotating cylinder 64 is provided with an annular groove 8 corresponding to the snap-fit ​​block 75. The arc length of the annular groove 8 corresponds to the arc length of the tooth surface of the second gear 65. The second gear 65 has a notch at a position away from the first gear 63 to allow 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 maintain a meshing state when rotating. The tooth surface of the second gear 65 is adapted to the tooth surface of the first gear 63.

[0037] In one embodiment of the present invention, the resistance component includes a guide ring 661. One end of the guide ring 661 is mounted on the inner wall of the bottom of the cavity inside the housing 4 via a fixing block. The other end of the guide ring 661 passes through the moving groove on the side of the second gear 65 and is fixedly connected to the other side of the fixing block. A slider 662 is slidably connected to the outer periphery of the guide ring 661 near the first gear 63. A first spring 663 is sleeved around the guide ring 661. The first spring 663 is configured as a ring structure. The two ends of the first spring 663 are respectively fixedly connected to the surfaces of the slider 662 and the fixing block. A moving groove is opened on one side of the second gear 65 corresponding to the guide ring 661. When the patient rotates his limb, the rotating block 5 rotates. The rotation of the rotating block 5 rotates the rotating rod 62. The rotation of the rotating rod 62 rotates the first gear 63. The rotation of the first gear 63 rotates the second gear 65. The rotation of the second gear 65 rotates the slider 662 along the guide ring 661, thereby squeezing the first spring 663 and generating resistance.

[0038] In one embodiment of the present invention, the adjusting assembly includes a push rod 71, which slides within a rotating cylinder 64. A first abutment block 72 is mounted on the surface of one end of the push rod 71 inside the rotating cylinder 64. First abutment rods 73 are mounted in three independent cavities at the top of the rotating cylinder 64. The top of each first abutment 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 each first abutment rod 73. A locking block 75 is provided at the bottom of the first abutment block 72, and the locking block 75 slides on the bottom of the first abutment block 72. Inside the limiting groove of the part, a third spring is fixedly connected to the top of the snap-fit ​​block 75. The end of the third spring away from the snap-fit ​​block 75 is connected to the top of the limiting groove. The first abutment block 72 is set as a semi-circular frustum structure with the inclined surface facing the rear side. The end of the snap-fit ​​block 75 is set as a sloping structure with the inclined surface facing the rear side. The first abutment block 72 is pushed into the rotating cylinder 64 by the push rod 71 to abut against the first abutment rod 73, so that the first abutment rod 73 moves upward. The upward movement of the first abutment rod 73 pushes the second gear 65 in the front cavity of the housing 4 to mesh with its corresponding first gear 63.

[0039] In one embodiment of the present invention, a protrusion 9 is fixedly connected to the bottom of the first abutting rod 73 near the push rod 71. A second abutting rod 10 is installed at the top of the rotating cylinder 64 corresponding to the protrusion 9. A sliding block is provided at the top of the second abutting rod 10. The sliding block slides laterally in the upper limit groove on the inner wall of the top of the rotating cylinder 64. A limit block is provided on the inner wall of the top of the rotating cylinder 64 corresponding to the sliding block. A fourth spring is arranged laterally 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 rotation point corresponding to the second abutting rod 10. When the first abutting rod 73 moves upward, it drives the protrusion 9 to abut against the second abutting rod 10, so that the second abutting rod 10 is inserted into the plug-in block 11.

[0040] In one embodiment of the present invention, a sliding groove is provided inside the barrier plate 61 corresponding to the slider 662. A ratchet 12 is provided at the bottom of the sliding groove, with several ratchet 12s evenly distributed along the bottom of the sliding groove. Three sets of ratchet 12s 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 contact plate 14 is provided at the front end of the moving block 13, and the contact plate 14 is connected to the moving block 13 by a torsion spring. A first hook block 15 is provided at the end of the contact plate 14. A second hook block 16 is provided at the rear end of the front side 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. A third contact 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. Several ratchet 12s are provided with contact teeth corresponding to the rotation arc length of the second gear 65. When the patient performs rehabilitation training, the limbs lose strength. When the second gear 65 rotates rapidly back under the action of the first spring 663, the abutment plate 14 will quickly engage with the ratchet 12, causing the second gear 65 to stop rotating and preventing secondary damage to the fracture area caused by 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. Then, the corresponding large abutment tooth will abut against the abutment plate 14, causing the abutment plate 14 to rotate upward. The upward rotation of the abutment plate 14 will drive the first hook block 15 to move upward. The first hook block 15 will move upward and engage with the second hook block 16 on the moving block 13. Then, the patient's limb will be slowly straightened. At this time, the third abutment rod 17 on the inner wall of the front end of the sliding groove will abut against the upper end of the second hook block 16, causing the second hook block 16 to deflect and disengage the first hook block 15 from the second hook block 16, thereby reducing the fracture.

[0041] Working principle: When using the main rod connection device of this type of external fixator, the fracture area of ​​the patient is first fixed by steel pins 2 and fixation plates. When the patient needs rehabilitation training in the early stage of recovery, the first abutting block 72 is pushed into the rotating cylinder 64 by the push rod 71 to abut the first abutting rod 73, causing the first abutting rod 73 to move upward. The upward movement of the first abutting rod 73 pushes the second gear 65 in the front cavity of the housing 4 to mesh with its corresponding first gear 63. Since the second gear 65 has an elliptical structure, the first gear 63 and the second gear 65 always remain in a meshed state when rotating. At the same time that the first abutting block 72 abuts the first abutting rod 73, the locking block 75 at the bottom of the first abutting block 72 will lock into the inner wall of the bottom end of the rotating cylinder 64. Within the annular groove 8, the patient rotates their limb, causing the rotating block 5 to rotate. The rotating block 5 rotates, causing the rotating rod 62 to rotate. The rotating rod 62 rotates, causing the first gear 63 to rotate. The first gear 63 rotates, causing the second gear 65 to rotate. The second gear 65 rotates, causing the slider 662 to move along the guide ring 661, thereby squeezing the first spring 663 and generating resistance. At the same time, the rotation of the second gear 65 also causes the rotating cylinder 64 in the front cavity to rotate, while the first abutting rod 73 does not rotate, allowing the locking block 75 to move along the inside of the annular groove 8. Meanwhile, since only a quarter tooth of the second gear 65 in the front cavity of the housing 4 engages with the corresponding annular groove 8, the patient's limb can only rotate 0° to 30°, thus meeting the patient's initial recovery training requirements.

[0042] When the patient needs retraining during the mid-recovery phase, the push rod 71 is pushed further into the rotating cylinder 64, thereby pushing the first abutment block 72 in the intermediate chamber area to abut the first abutment rod 73 upwards. The corresponding first gear 63 and second gear 65 in the intermediate chamber mesh, and the locking block 75 at the bottom of the first abutment block 72 engages with the corresponding annular groove 8 on the inner wall of the bottom end of the rotating cylinder 64. The upward movement of the first abutment rod 73 simultaneously causes the protrusion 9 to abut the second abutment rod 10, causing the second abutment rod 10 to insert into the insertion block 11. At this time, the patient rotates their limb, causing the rotating block 5 to rotate, which in turn causes the rotating rod 62 to rotate, which in turn causes the first gear 63 to rotate, which in turn causes the second gear 65 to rotate. Since the second abutment rod 10 is inserted into the insertion block 11, it also causes the rotating cylinder 64 in the anterior chamber to rotate, causing the second gear 65 in both chambers to rotate, simultaneously driving... The slider 662 moves along the guide ring 661, squeezing the two sets of first springs 663, thereby increasing the resistance when the patient's limb rotates. At the same time, because only one-third of the teeth of the second gear 65 in the intermediate cavity of the housing 4 engage with the corresponding annular groove 8, the patient's limb can only rotate 0° to 90°. In the later stage of recovery, the push rod 71 is pushed to move into the rotating cylinder 64, thereby pushing the first abutting block 72 in the rear intercavity area to abut against the first abutting rod 73 and move upward. Then the above operation is repeated to further increase the resistance when the limb rotates. At the same time, because only half of the teeth of the second gear 65 in the intermediate cavity of the housing 4 engage with the corresponding annular groove 8, the patient's limb can move freely (such as above 90°). When the push rod 71 needs to be reset, it can be pushed forward until the locking block 75 disengages from the annular groove 8 on the rear side of the rotating cylinder 64. Then the push rod 71 is rotated 180° and pulled outward, and finally locked and fixed.

[0043] When the patient is undergoing rehabilitation training and the limb is releasing force, the second gear 65 rotates rapidly back under the action of the first spring 663. At this time, the abutment plate 14 will quickly engage with the ratchet 12, causing the second gear 65 to stop rotating and preventing secondary damage to the fracture area caused by the rebound force of the first spring 663. When reduction is needed, the medical staff will slowly rotate the patient's limb until it is rotated to the corresponding angle. Then, the corresponding large abutment tooth will abut against the abutment plate 14, causing the abutment plate 14 to rotate upward. The upward rotation of the abutment plate 14 will drive the first hook block 15 to move upward. The first hook block 15 moves upward so that it engages with the second hook block 16 on the moving block 13. Then, the patient's limb is slowly straightened. At this time, the third abutment rod 17 on the inner wall of the front end of the sliding groove will abut against the upper end of the second hook block 16, causing the second hook block 16 to deflect and disengage the first hook block 15 from the second hook block 16, thereby reducing the fracture.

[0044] Contents not described in detail in this specification are prior art known to those skilled in the art. In the description of this invention, unless otherwise stated, "a plurality of" means two or more. Terms such as "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," and "tail" indicate orientations or positional relationships based on the accompanying drawings, and are used only for ease of description and simplification, not to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the invention. Furthermore, terms such as "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. In the description of this invention, it should be noted that unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0045] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A main rod connecting device of an external fixator for bone, comprising a fixing rod (1), characterized in that: The fixed rod (1) is internally provided with a steel needle (2), the fixed rod (1) is provided with two groups, and the opposite ends of the two groups of fixed rods (1) are provided with universal joints (3); the universal joints (3) are provided with a shell (4) between the two groups, the bottom end of the rear side of the shell (4) is fixedly connected with the top of the lower end universal joint (3), the top end of the rear side of the shell (4) is rotatably connected with a rotating block (5), the rotating block (5) is fixedly connected with the upper end universal joint (3), a hierarchical rotating mechanism is internally arranged in the shell (4), and an adjusting assembly is arranged at the lower end of the front side of the shell (4); The hierarchical rotating mechanism comprises a blocking plate (61) arranged in the shell (4), the blocking plate (61) is provided with two groups, and the space in the shell (4) is divided into three independent cavities, the upper end of the blocking plate (61) is rotatably connected with a rotating rod (62), the rear end of the rotating rod (62) extends out of the shell (4) and is connected with the rotating block (5), the front end of the rotating rod (62) is rotatably connected with the inner wall of the front side of the shell (4) through the blocking plate (61), and three groups of first gears (63) are arranged on the surface of the rotating rod (62) corresponding to the positions of the three independent cavities; a rotating drum (64) is arranged in the shell (4) below the first gear (63), second gears (65) are arranged on the surface of the rotating drum (64) corresponding to the first gears (63), and a resistance assembly is arranged in the second gear (65). The adjusting assembly comprises a push rod (71), the push rod (71) is limitedly slid in the rotating drum (64), a first abutting block (72) is arranged on the surface of one end of the push rod (71) in the rotating drum (64), first abutting rods (73) are arranged on the top of the rotating drum (64) corresponding to the three independent cavities, the top of the first abutting rod (73) extends out of the rotating drum (64) and is fixedly connected with the inner wall of the second gear (65), a second spring (74) is arranged on the surface of the periphery of the first abutting rod (73), a clamping block (75) is arranged on the bottom of the first abutting block (72), the clamping block (75) is slid in the limiting sliding groove in the bottom of the first abutting block (72), a third spring is fixedly connected to the top of the clamping block (75), and one end of the third spring, away from the clamping block (75), is connected with the top of the limiting sliding groove. The first gears (63) and the second gears (65) are provided with three groups corresponding to the three independent cavities, the second gears (65) are in an oval structure, and are sequentially provided with a quarter of a tooth, a third of a tooth and a half of a 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 through a bearing, a ring-shaped groove (8) is formed on the inner wall of the bottom of the rotating drum (64) corresponding to the clamping block (75), and the arc length of the ring-shaped groove (8) corresponds to the arc length of the tooth surface of the second gear (65).

2. A main rod coupling device for an external bone fixation frame according to claim 1, characterized in that: 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, the other end of the guide ring (661) is fixedly connected with the other side of the fixed block through the moving slot of the side end of the second gear (65), the periphery of one end of the guide ring (661) close to the first gear (63) is slidably connected with a sliding block (662), and the periphery of the guide ring (661) is sleeved with a first spring (663).

3. A main rod coupling device for an external bone fixation frame according to claim 2, characterized in that: The first resistance rod (73) is fixedly connected with a protrusion (9) on one side close to the push rod (71) at the bottom, a second resistance rod (10) is installed on the top end of the inner wall of the rotating drum (64) corresponding to the protrusion (9), a sliding block is arranged on the top of the second resistance rod (10), the sliding block is transversely slidably arranged in the limiting sliding groove on the top end of the inner wall of the rotating drum (64), a limiting block is arranged on the top end of the inner wall of the rotating drum (64) corresponding to the sliding block, a fourth spring is transversely arranged between the sliding block and the limiting block, and a plug-in block (11) is installed on the inner wall close to the rotating position of the rotating drum (64) corresponding to the second resistance rod (10).

4. A main rod coupling device for an external bone fixation frame according to claim 3, characterized in that: A sliding groove is formed in the inner wall of the resistance plate (61) corresponding to the sliding block (662), a plurality of ratchet teeth (12) are arranged on the inner bottom of the sliding groove, a moving block (13) is arranged on one side of the sliding block (662) and extends into the sliding groove, a resistance plate (14) is arranged on 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 arranged at the tail end of the resistance plate (14), a second hook block (16) is arranged on the front end of the moving block (13) corresponding to the first hook block (15), the second hook block (16) and the moving block (13) are connected by a torsion spring, and a third resistance rod (17) is fixedly connected to the top of the second hook block (16) on the front end of the inner wall of the sliding groove.

5. A main rod coupling device for an external bone fixation frame according to claim 4, characterized in that: The second gear (65) is provided with a notch away from the first gear (63), the first spring (663) is in an annular structure, and the two ends of the first spring (663) are fixedly connected to the surface of the sliding block (662) and the fixed block respectively.

6. A main rod coupling device for an external bone fixation frame according to claim 5, wherein: The first resistance block (72) is in a semicircular table structure with an inclined surface facing the rear side, the tail end of the clamping block (75) is in a slope structure with an inclined surface facing the rear side, a moving slot is formed in one side of the second gear (65) corresponding to the guide ring (661), and a plurality of ratchet teeth (12) are provided with resistance teeth corresponding to the rotation angle of the second gear (65).

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