Anti-coagulation central venous catheter device based on gear and rack meshing excitation

Abstract

The application discloses an anti-coagulation central venous catheter device based on gear and rack meshing type excitation, which comprises a gear and rack type linear reciprocating driving mechanism and a central venous catheter; the front end of a push rod in the gear and rack type linear reciprocating driving mechanism extends into the central venous catheter, the front end of the push rod is connected with a sealing connecting piece, and the rear end of the push rod is connected with the front end of a transmission rack; a driving motor is fixedly connected with a driving gear through a motor output shaft, the driving gear is engaged with the transmission rack, the transmission rack is slidably arranged on a guide rail, limit switches are arranged on the tail of the transmission rack, and the limit switches are movably arranged on the side edges outside the length direction of the guide rail and are movably connected with the limit switches. The application can continuously and directly adjust the reciprocating stroke of the push rod in a preset range, does not need to disassemble the device and replace any parts, is convenient to operate, can flexibly set the excitation strength according to the individual differences of patients, and effectively improves the clinical adaptability of the device.

Description

Technical Field

[0001] This invention relates to a central venous catheter, and more particularly to an anticoagulation central venous catheter device based on gear and rack meshing vibration. Specifically, it relates to a wearable physical anticoagulation central venous catheter device based on stable periodic excitation outside the body and adjustable shear force on the catheter wall inside the body, belonging to the field of medical device technology. Background Technology

[0002] Hemodialysis is one of the key treatments for end-stage renal disease patients to maintain their lives, and central venous catheters (CVCs), as important tools for establishing temporary or long-term vascular access, are widely used in clinical practice. However, CVC use is often accompanied by catheter-related thrombosis, which has become a major cause of late-stage functional impairment. Thrombosis not only easily leads to decreased catheter flow and loss of function, but can also cause serious complications such as deep vein thrombosis and pulmonary embolism, severely affecting the patient's treatment outcome and even threatening life. Therefore, effectively preventing CVC-related thrombosis is crucial for prolonging catheter lifespan and reducing clinical risks for patients, and has significant clinical implications.

[0003] In recent years, optimizing catheter design and anticoagulation strategies to prevent thrombosis has been listed as one of the "Top Ten Innovation Directions" in the field of nephrology. Currently, research is being advanced from two main perspectives: firstly, focusing on the development of anticoagulant coatings and the application of novel anticoagulants; secondly, based on hemodynamic mechanisms, improving catheter structure and material properties. However, existing anticoagulation methods still struggle to balance anticoagulation effectiveness and clinical safety. Anticoagulant coatings suffer from problems such as easy detachment, short effective duration, and potential systemic anticoagulation side effects; drug-locking strategies are limited by rapid drug metabolism, require repeated procedures, and have limited effectiveness in patients with hypercoagulable states. Regarding structural design, while methods such as side-hole design and material improvements have been developed, the fundamental problems of thrombosis caused by blood stasis and protein adsorption have not been resolved.

[0004] Chinese invention patent CN113857164B discloses a pulse-type automatic flushing device for central venous catheters, comprising a pulse generating device and a central venous catheter. The bottom of the cylinder of the pulse generating device is connected to an outlet pipe. A piston is slidably installed inside the cylinder. A force transmission column is slidably installed between a lifting plate and the top of the cylinder. One end of the force transmission column extends into the cylinder, and a force transmission plate is fixed on the extended end. Multiple springs are fixed between the force transmission plate and the piston, and a force receiving plate is fixed on the extended end. A gantry frame is fixed on the outer wall of the cylinder. The crossbeam of the gantry frame is located directly above the force receiving plate. An electric cylinder is fixed on the top of the crossbeam of the gantry frame. The piston rod of the electric cylinder passes through the crossbeam, and a striking block is fixed on the actuating end of the piston rod. The first port of the central venous catheter is interference-fitted onto the bottom port of the outlet pipe. The technique involves repeatedly striking a pressure plate with a striking block, creating a pulsating fluid flow within the central venous catheter (CVC). This pulsating flow of saline flushes away blood and medication adhering to the CVC's inner wall, allowing them to enter the blood vessel and thus achieving pulsed flushing. However, this technique relies on an electric cylinder to drive the striking block to intermittently strike the pressure plate, generating pulses. This impact-based mechanical transmission method makes it difficult to achieve stable and precise control over the pulse waveform, frequency, and amplitude, resulting in low-precision and uncontrollable impact pulses. Furthermore, this technique utilizes pulsating fluid to flush away blood and medication deposits already adhering to the catheter's inner wall, representing a post-treatment cleanup of existing deposits. The flushed particles directly enter the bloodstream, posing a potential risk of embolism. Additionally, the technique, comprising components such as the cylinder, piston, gantry, electric cylinder, and striking block, is bulky and heavy, requiring operation on a stable surface like a table, making it unsuitable for patients' daily activities and portability needs during long-term catheterization. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies, this invention provides an anticoagulation central venous catheter device based on rack and pinion vibration that can reduce the risk of thrombosis from the source, allows for continuous and direct adjustment of the push rod reciprocating stroke within a preset range, requires no disassembly or replacement of any parts, is easy to operate, and allows for flexible setting of the excitation intensity according to individual patient differences.

[0006] A pulse is a signal or excitation that releases energy instantaneously, emphasizing its brief duration (e.g., shock, square wave), and is an intermittent, impulsive, and discontinuous energy output. Compared to the pulse action described in the existing Chinese invention patent CN113857164B, the excitation-based anticoagulation central venous catheter system has significant advantages. Excitation (or vibration excitation) is a continuously applied periodic or random excitation, emphasizing the continuity of the process (e.g., sinusoidal frequency sweep, random vibration). A pulse is a "one-shot" instantaneous action, while excitation is a "continuously driven" dynamic process.

[0007] Regarding pulsed anticoagulation central venous catheters, the applicant has proposed an anticoagulation central venous catheter system based on excitation force. This application utilizes a cam to provide excitation force. The rear end of the push rod is connected to an eccentric cam, and a spring is sleeved on the push rod. Spring supports are provided at both ends of the spring. The spring support on the side closer to the eccentric cam is fixedly connected to the push rod, and the spring support on the other side is connected to the frame. Under the action of the spring, the push rod always maintains close contact with the working surface of the eccentric cam. When the eccentric cam rotates, it pushes the push rod to perform axial reciprocating motion. However, the inventors later discovered that although the technology could overcome the problems of pulse-based central venous catheters, it also had its own problem that the reciprocating stroke of the push rod could not be directly and continuously adjusted. Because the reciprocating stroke of the push rod is uniquely determined by the eccentricity of the eccentric cam, and the eccentricity is a fixed structural parameter formed during the cam manufacturing process, once the cam is completed, it cannot be changed during use. Therefore, if the excitation stroke needs to be changed in clinical use, it can only be done by disassembling the machine and replacing the cam parts with different eccentricity specifications. It cannot be implemented quickly in the clinical field, and can only rely on a few fixed eccentricity specifications to achieve limited gear switching, and cannot achieve continuous adjustment.

[0008] To avoid the above problems, the present invention adopts the following technical solution:

[0009] An anticoagulant central venous catheter device based on rack and pinion meshing excitation includes a rack and pinion linear reciprocating drive mechanism and a central venous catheter. The push rod in the rack and pinion linear reciprocating drive mechanism extends into the central venous catheter, which is filled with saline solution. The front end of the push rod is connected to a sealing connector, and the outer periphery of the sealing connector forms a mating gap with the inner wall of the central venous catheter. The thickness of the mating gap is 0.01-0.05 mm, and the axial length is 1.0-15.0 mm. The rear end of the push rod is connected to the front end of a transmission rack. A drive motor is fixedly connected to a drive gear via its output shaft, and the drive gear meshes with the transmission rack. The transmission rack is slidably mounted on a guide rail. A limit switch is provided at the tail of the transmission rack, and two limit switches are separately and movably mounted on the side of the guide rail along its length. The limit switch is movably connected to the two limit switches. The drive motor is electrically connected to a voltage regulation module, a rechargeable battery, a time control relay, and the two limit switches.

[0010] To further achieve the purpose of this invention, preferably, the guide rail is disposed at the bottom of the frame along the extension direction of the push rod; the limit switch is movably installed in the adjustment groove through a sliding locking seat, and the adjustment groove is disposed on the inner wall of the frame.

[0011] Preferably, the limit switch is a mechanical contact type limit switch; the adjusting groove is a non-through straight groove; the frame is a sealed cavity structure; the drive gear, transmission rack, push rod, sealing connector, guide rail, limit lever, two limit switches, drive motor, voltage regulation module, rechargeable battery, and time control relay are all disposed inside the cavity; the maximum external dimensions of the frame do not exceed 60mm×30mm×30mm.

[0012] Preferably, the guide rail is a long strip-shaped monorail with an inverted T-shaped or I-shaped cross-section, and the top of the guide rail is a flat surface that has been precision ground; the bottom of the transmission rack is provided with a groove, and the top of the guide rail is set in the groove; the rear end of the push rod is connected to the front end of the transmission rack by any one of the following methods: threaded connection, pin connection, interference fit, or adhesive bonding.

[0013] Preferably, the frame end is provided with a detachable connector, and the frame is sealed to the end of the central conduit through the detachable connector.

[0014] Preferably, the distance between the two limit switches along their length is 1cm to 3cm.

[0015] Preferably, the drive motor is fixedly connected to the drive gear through the motor output shaft passing through the motor shaft mounting hole on the drive gear; the sealing connector is a plunger head, piston head, or ball head; the sealing connector is made of a biocompatible elastic material; the gear and rack linear reciprocating drive mechanism also includes a charging port and a power switch, the charging port being electrically connected to the rechargeable battery; the power switch and the rechargeable battery are connected via an internal connecting wire.

[0016] Preferably, the sealing connector is made of medical-grade silicone, medical-grade polyurethane, or fluororubber; the rechargeable battery is also electrically connected to the voltage regulation module, the time control relay, and the two limit switches.

[0017] Preferably, multiple rack and pinion linear reciprocating drive mechanisms are provided, and each rack and pinion linear reciprocating drive mechanism is connected to a single cavity of the central venous catheter.

[0018] Preferably, the overall weight of the gear and rack linear reciprocating drive mechanism does not exceed 50g;

[0019] The ratio of the axial length to the thickness of the fitting clearance is controlled within (50-300):1.

[0020] Compared with the prior art, the present invention has the following advantages and beneficial technical effects:

[0021] 1) In this invention, the rear end of the push rod is fixedly connected to the front end of the transmission rack, and a limiting paddle is fixedly installed at the tail end of the transmission rack. An adjustment groove for mounting the limit switches is opened on the inner wall of the frame, and the two limit switches are respectively installed in the adjustment groove through sliding seats. The limiting paddle moves synchronously with the transmission rack. When it moves to the limit position, it touches the corresponding limit switch, and the limit switch sends an electrical signal to the drive motor to switch the motor rotation direction, realizing automatic reciprocating reversal. In clinical use, it is only necessary to slide the two limit switches along the adjustment groove to change the axial distance between them and lock them. The reciprocating stroke of the push rod can be continuously and directly adjusted within a preset range (preferably 1cm to 3cm in this invention). No disassembly or replacement of any parts is required. The operation is convenient, and the excitation intensity can be flexibly set according to individual patient differences, effectively improving the clinical adaptability of the device.

[0022] 2) Addressing the issue that the size of cam-type systems is limited by the spring return mechanism and the dimensions of the eccentric cam itself, and that assembly steps are numerous, this invention designs a parallel meshing arrangement of the drive gear and the transmission rack. The radial dimension of the drive gear is perpendicular to the movement direction of the transmission rack, without increasing the overall length of the machine in the push rod movement direction. Furthermore, it eliminates the need for springs and two spring supports, saving space for spring extension and contraction, support installation positions, and the occupancy of the cam's radial dimension. This results in a simpler and more compact transmission structure and a significantly reduced overall machine size. Simultaneously, the drive gear and transmission rack only need to maintain a standard meshing clearance, eliminating the need to adjust the spring preload. The limit switch and limit lever only need to ensure normal contact, significantly reducing assembly steps and lowering production difficulty.

[0023] 3) This invention establishes a quantitative relationship between wall shear force and push rod motion parameters. The motor speed can be adjusted by the control unit to change the excitation cycle, the working and intermittent durations can be set by the time control module, and the push rod reciprocating stroke and excitation amplitude can be freely adjusted by the limit switch. This enables quantitative and precise active intervention in the wall shear force intensity, significantly improving the controllability and accuracy of the anti-coagulation process.

[0024] 4) This invention controls the thickness of the mating gap to be 0.01-0.05 mm and the axial length to be 1.0-15.0 mm. This mating gap is a precision dynamic seal gap, which can prevent the push rod from getting stuck due to an excessively small gap, and also prevent the excitation energy from leaking and attenuating due to an excessively large gap. This ensures that the excitation energy can be stably transmitted to the entire length of the catheter and the tip, achieving a continuous and stable anticoagulation effect. This invention can control the formation of a controllable wall shear force on the inner wall of the central venous catheter within the safe range of 0.5 Pa to 15 Pa, preemptively inhibiting platelet adhesion, aggregation, and fibrin deposition, and achieving thrombosis prevention from the source.

[0025] 5) This invention eliminates the need for anticoagulants and generates controllable wall shear force through mechanically stable periodic excitation force, thereby interfering with the formation of thrombus precursors at the physical level. This fundamentally avoids the bleeding risk caused by anticoagulants and is particularly suitable for patients with contraindications to bleeding, significantly improving the safety of clinical use.

[0026] 6) The device of this invention has a high degree of integration, small size, and light weight, making it easy to install and use in clinical environments such as ICU and wards without taking up too much space. Patients can carry it with them and work continuously without affecting their daily activities, truly realizing "wearable continuous anticoagulation". It breaks through the limitations of existing technologies that must restrict patients' activities. In addition, the invention uses a quick connector, and the connection with the catheter is simple and quick, which greatly improves the work efficiency of medical staff and reduces the difficulty of operation and time cost. Attached Figure Description

[0027] Figure 1 A schematic diagram of the components of an anticoagulant central venous catheter device based on gear and rack meshing vibration.

[0028] Figure 2 for Figure 1 Schematic diagram of AA section;

[0029] Figure 3 for Figure 2 Enlarged image;

[0030] Figure 4 for Figure 1 A schematic diagram of the structure of the rack and pinion linear reciprocating drive mechanism 1;

[0031] Figure 5 Example 2 shows the wall shear force-time curve at a distance of 10 mm from the tip of the conduit when the excitation period is 0.25 s.

[0032] Figure 6 Example 2 shows the wall shear force-time curve at a distance of 20 mm from the tip of the conduit when the excitation period is 0.25 s.

[0033] Figure 7 Example 2 shows the wall shear force-time curve at a distance of 30 mm from the tip of the conduit when the excitation period is 0.25 s.

[0034] Figure 8 Example 2 shows the wall shear force-time curve at a distance of 40 mm from the tip of the conduit when the excitation period is 0.25 s.

[0035] Figure 9 The curves showing the maximum and minimum values ​​of the shear force on the guide tube wall as a function of position under different excitation cycles with an excitation stroke of 3cm in Example 2 are shown.

[0036] Figure 10 The image shows the distribution cloud map of shear force on the guide tube wall under different excitation cycles (t=30s) with an excitation stroke of 3cm in Example 2, corresponding to cycles of 0.2s, 0.25s, and 0.3s, respectively.

[0037] The diagram shows: 1. Gear and rack linear reciprocating drive mechanism; 2. Drive gear; 3. Transmission rack; 4. Push rod; 5. Sealing connector; 6. Central venous catheter; 7. Motor shaft mounting hole; 8. Frame; 9. Detachable connector; 10. Fitting clearance between sealing connector and inner wall of catheter; 11. Drive motor; 12. Motor output shaft; 13. Voltage regulation module; 14. Power switch; 15. Internal connection wire; 16. Charging port; 17. Rechargeable battery; 18. Time control relay; 19. Limit switch; 20. Guide rail; 21. Limit lever. Detailed Implementation

[0038] To better understand the present invention, further description is provided below with reference to the accompanying drawings and specific embodiments. However, the implementation of the present invention is not limited thereto. The described embodiments are some, but not all, of the embodiments of the present invention. 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.

[0039] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "communication," and "linkage" 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; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0040] The central venous catheter of this invention conforms to the ISO 10555 series of standards.

[0041] The limitations of cam-type vibratory central venous catheter pusher stroke are addressed by the fact that the stroke is not adjustable. Furthermore, in cam-type systems, to achieve pusher reverse reset, a spring needs to be fitted onto the pusher with two spring supports. The spring's extension / retraction space, the installation positions of the two supports, and the radial dimension of the eccentric cam itself all occupy internal space in the drive mechanism, making further reduction in overall size difficult. Simultaneously, during assembly, the pusher must be inserted into the spring, aligned with the two spring supports, and the spring preload must be appropriate to ensure the pusher remains in contact with the eccentric cam's working surface during high-speed movement. This requires high assembly precision, increasing production difficulty and the complexity of quality control. The inventors discovered that an anticoagulant central venous catheter device based on rack and pinion vibration can effectively overcome the problems of cam-type vibratory central venous catheters. The core of this device is replacing the cam system with a rack and pinion system. Specifically, the rear end of the push rod is connected to the front end of the transmission rack; the drive motor is fixedly connected to the drive gear through the motor output shaft, and the drive gear meshes with the transmission rack; the transmission rack is slidably mounted on the guide rail; a limit plate is provided at the tail of the transmission rack, and two limit switches are separately and movably mounted on the side of the guide rail along its length, with the limit plate movably connected to the two limit switches; the drive motor is electrically connected to the voltage regulation module, the rechargeable battery, the time control relay, and the two limit switches respectively.

[0042] In the above technical measures, the guide rail is preferably located at the bottom of the cavity along the extension direction of the push rod; the limit switch is movably installed in the adjustment groove through a sliding locking seat, and the adjustment groove is preferably located on the inner wall of the frame. The limit switch is preferably a mechanical contact type limit switch; the adjustment groove is preferably a non-through straight groove; the frame is a sealed cavity structure; the drive gear, transmission rack, push rod, sealing connector, guide rail, limit lever, two limit switches, drive motor, voltage regulation module, rechargeable battery, and time control relay are all located inside the cavity; the maximum external dimensions of the controllable frame do not exceed 60mm × 30mm × 30mm.

[0043] The guide rail is preferably a long strip monorail with an inverted T-shaped or I-shaped cross section, and the top of the guide rail is a precision-ground flat surface; the bottom of the transmission rack is provided with a groove, and the top of the guide rail is set in the groove; the rear end of the push rod is connected to the front end of the transmission rack by any one of the following methods: threaded connection, pin connection, interference fit, or adhesive bonding.

[0044] The distance between the two limit switches along their length is 1cm to 3cm. This means that the distance along the length can be changed by sliding along the adjustment groove of the frame, thereby limiting the reciprocating stroke of the push rod. The push rod stroke adjustment range is 1cm to 3cm.

[0045] Example 1

[0046] As shown in Figures 1 to 4, the anticoagulant central venous catheter device based on rack and pinion meshing excitation includes a rack and pinion linear reciprocating drive mechanism 1 and a central venous catheter 6. The rack and pinion linear reciprocating drive mechanism 1 is a highly integrated miniature wearable mechatronic device. Its specific structure, as shown in Figure 4, includes: a frame 8, a drive gear 2, a transmission rack 3, a push rod 4, a sealing connector 5, a detachable connector 9, a drive motor 11, a voltage regulation module 13, a rechargeable battery 17, a time control relay 18, two limit switches 19, a guide rail 20, and a limit lever 21. The frame 8 is a sealed cavity structure, and the drive gear 2, transmission rack 3, push rod 4, sealing connector 5, drive motor 11, voltage regulation module 13, rechargeable battery 17, time control relay 18, two limit switches 19, guide rail 20, and limit lever 21 are all housed within the cavity of the frame 8.

[0047] The drive motor 11 is fixedly connected to the drive gear 2 via the motor output shaft 12; preferably, the drive motor 11 is fixedly connected to the drive gear 2 via the motor output shaft 12 passing through the motor shaft mounting hole 7 on the drive gear 2, so as to drive the drive gear 2 and the drive motor 11 to rotate synchronously. The guide rail 20 is fixedly installed inside the frame 8. The push rod 4 extends into the central venous catheter 6, which is filled with saline solution. The front end of the push rod 4 is connected to the sealing connector 5. The outer periphery of the sealing connector 5 forms a fitting gap 10 with the inner wall of the central venous catheter 6. The thickness of the fitting gap 10 is 0.01 to 0.05 mm, and the axial length is 1.0 mm to 15.0 mm. The rear end of the push rod 4 is detachably and fixedly connected to the front end of the transmission rack 3. The detachable and fixed connection method is preferably any one of threaded connection, pin connection, interference fit, or bonding. The transmission rack 3 continuously meshes with the drive gear 2. When the drive gear 2 rotates forward and in reverse, it directly drives the transmission rack 3 to slide back and forth along the upper surface of the guide rail 20. The push rod 4 moves synchronously with the transmission rack. The guide rail 20 only serves as a linear guide structure for the transmission rack 3. The transmission rack 3 has a limit lever 21 fixed at its tail. The inner wall of the frame 8 is provided with a long strip-shaped adjustment groove extending along the direction of the push rod's movement. This adjustment groove is only used to assemble the limit switch and does not contact the transmission rack 3. The two limit switches 19 are equipped with sliding locking seats and are assembled in the adjustment groove of the frame 8. The limit lever 21 moves synchronously with the transmission rack and push rod and touches the limit switches 19 on both sides. After receiving the touch signal, the limit switch controls the circuit to switch the rotation direction of the drive motor 11. By sliding and adjusting the distance between the two limit switches 19 in the length direction within the adjustment groove, the limit position of the push rod's reciprocating motion can be changed, and the reciprocating stroke of the push rod 4 can be freely limited, thereby adjusting the amplitude of the excitation intensity. The entire movement is smooth without jamming or slippage.

[0048] The guide rail 20 is a long strip monorail with an inverted "T" shaped cross section, or it can be a long strip monorail with an I-shaped cross section. Its length extends along the movement direction of the push rod 4. The bottom of the guide rail 20 is fixedly installed on the inner bottom of the frame 8 by bolts and is located in the middle section of the frame 8 along the movement direction of the push rod. The top of the guide rail 20 is a precision-ground flat surface. This flat surface slides in conjunction with the guide groove at the bottom of the transmission rack 3. The bottom of the transmission rack is provided with a slot, and the top of the guide rail is set in the slot. The transmission rack 3 can slide freely back and forth on the guide rail 20 along its length direction, thereby achieving precise linear guidance for the transmission rack 3 and the push rod 4 fixedly connected to it.

[0049] Both limit switches 19 are mechanical contact type limit switches. The two sets of adjustable limit switches 19 are respectively installed in the adjustment grooves opened on the inner side wall of the frame 8 via sliding locking seats, and are respectively positioned on both sides of the limit lever 21 along the movement direction of the push rod 4. The contact ends of both limit switches face the direction of the limit lever 21, so that when the limit lever 21 reciprocates to its extreme positions, it can respectively contact the corresponding limit switch contacts. The two limit switches can slide independently within the adjustment grooves along the movement direction of the push rod 4 and are fixed in any position by the locking seats. The distance between the two limit switches in the direction of push rod movement is the travel distance of the limit lever 21, which is also the reciprocating stroke of the push rod 4. When the limiting paddle 21 fixed to the tail of the transmission rack 3 moves synchronously with the transmission rack 3 and the push rod 4 to one extreme position, the limiting paddle 21 touches the contact of the limit switch 19 on that side. The limit switch 19 then sends a reversing electrical signal to the control circuit of the drive motor 11, controlling the drive motor 11 to switch the rotation direction. The drive gear 2 then rotates in the opposite direction, and the transmission rack 3 and the push rod 4 move in the opposite direction. When the reverse movement reaches the other extreme position, the limiting paddle 21 touches the other limit switch 19, and the reversing occurs again. By changing the distance between the two limit switches in the adjustment groove, the travel distance of the limiting paddle 21 can be adjusted, thereby adjusting the reciprocating stroke of the push rod 4. In clinical use, it is only necessary to loosen the locking seat, slide the limit switch along the adjustment groove to the target position, and then relock it to achieve stepless continuous adjustment of the push rod reciprocating stroke within the range of 1cm to 3cm.

[0050] The adjustment groove is a non-through straight groove set on the inner wall of the frame 8, extending along the movement direction of the push rod 4, and the extension direction is consistent with the length direction of the guide rail 20. The position of the adjustment groove is adjacent to the guide rail 20. The sliding locking seats of the two limit switches 19 are respectively embedded in the adjustment groove and can slide freely along its length direction. The sliding locking seats can be fixed at any position in the adjustment groove by the locking member, thereby realizing the arbitrary adjustment of the distance between the two limit switches in the length direction, that is, realizing the setting of the reciprocating stroke of the push rod 4.

[0051] The limiting lever 21 is a sheet-like metal piece fixedly mounted on the tail of the transmission rack 3 (i.e., the end away from the push rod 4). The limiting lever 21 extends straight outward from the tail of the transmission rack 3 in a direction perpendicular to the movement direction of the push rod 4, and the extended end of the limiting lever 21 is located between the contacts of the two limit switches 19. When the transmission rack 3 drives the limiting lever 21 to move to one side's limit position, the extended end of the limiting lever 21 contacts the limit switch 19 on the corresponding side, triggering an electrical signal to reverse the direction of the drive motor 11; when the transmission rack 3 moves in the opposite direction to the other side's limit position, the extended end of the limiting lever 21 contacts the limit switch 19 on the other side, triggering an electrical signal again to reverse the direction of the drive motor 11 again, and so on, to realize the automatic reciprocating linear motion of the push rod 4.

[0052] The frame 8 of the rack and pinion linear reciprocating drive mechanism 1 is sealed to the central venous catheter 6 via a detachable connector 9. The drive motor 11 is connected to the voltage regulation module 13, the rechargeable battery 17, the time control relay 18, and the two limit switches 19, respectively; the rechargeable battery 17 is also connected to the voltage regulation module 13 and the time control relay 18, respectively.

[0053] The rechargeable battery 17 serves as the power source for the entire mechanism, providing stable operating power to components such as the drive motor 11, voltage regulation module 13, time control relay 18, and two limit switches 19. The charging port 16 is electrically connected to the rechargeable battery 17, allowing access to an external charging power source to replenish its energy and ensure long-term cyclical operation. The power switch 14 is connected to the rechargeable battery 17 via an internal connection wire 15, controlling the power supply to the entire mechanism and enabling system startup and shutdown. The voltage regulation module 13 is connected in series in the power supply circuit of the drive motor 11. By adjusting the operating voltage applied across the drive motor 11, it changes the output speed of the drive motor 11, thereby precisely adjusting the rotational speed of the drive gear 2, ultimately achieving adjustable and controllable frequency of the push rod 4's reciprocating motion. The time control relay 18 is connected in series in the power supply circuit of the drive motor 11. It allows for the preset continuous operating time and intermittent stop time of the drive motor 11, automatically switching the power supply on or off according to the preset sequence, so that the push rod 4 reciprocates and automatically stops according to a set cycle. Through the coordinated operation of the voltage regulation module 13 and the time control relay 18, the reciprocating frequency, single working time, and intermittent time of the push rod 4 can be independently and precisely set and adjusted. Combined with the limit switch 19 adjusting the push rod stroke, this multi-dimensional coordination enables the mechanism to output stable, controllable, and periodic vibration motion that meets anti-condensation requirements.

[0054] The voltage regulation module 13 is a mechanically adjustable voltage control unit. Preferably, the voltage regulation module 13 allows for manual and continuous adjustment of the output voltage amplitude via a rotary knob, changing the supply voltage across the drive motor and thus continuously adjusting the motor's operating speed. The change in motor speed directly corresponds to the cycle length of a single reciprocating motion of the push rod, thereby achieving continuous and precise adjustment of the push rod's mechanical excitation frequency. The actual voltage regulation range of the voltage regulation module 13 is limited to 3V–12V, within the allowable range of the drive motor's rated operating voltage; correspondingly, it matches and forms a push rod excitation frequency control range of 1Hz–100Hz. This voltage and frequency control range is comprehensively determined based on actual clinical anticoagulation needs and central venous catheter specifications. It can stably generate effective wall shear force on the catheter inner wall to meet thrombosis prevention requirements, while avoiding the risks of hemolysis, excessive overall vibration amplitude, and excessive power consumption caused by excessive frequency. The voltage and frequency control ranges have clear boundaries, strong adaptability to operating conditions, and good safety and clinical applicability.

[0055] The time control relay 18 is a time control unit integrated into the device control circuit. It has independently adjustable single working duration and rest duration of the drive motor, and automatically connects or disconnects the power supply circuit of the drive motor according to the preset time to control the drive motor 11 and the rack and pinion linear reciprocating drive mechanism 1 to achieve periodic intermittent operation. The adjustable time range of the time control relay 18 is 0.1s to 72h. The working duration and rest duration can be set independently within this range without interfering with each other. The upper limit of 72h is set according to the clinical routine indwelling period of the central venous catheter (usually 3 days), and the lower limit of 0.1s is the smallest settable time unit. Based on the requirements of anticoagulation efficacy and low power consumption, the working duration is preferably 0.1s to 10min to implement short-term and efficient excitation. The rest duration is set according to the thrombus formation dynamics, which aims to actively apply excitation force before the formation of thrombus precursors, thereby blocking the thrombus formation chain in advance with minimal energy consumption. The aforementioned adjustment range enables the device to operate in an intermittent mode, significantly extending its in-vivo life with the same battery capacity, while avoiding overheating issues caused by continuous motor operation. It features clear time adjustment boundaries, strong clinical adaptability, low power consumption, and long battery life. The voltage regulation module 13 works in conjunction with the time control relay 18 to control the excitation frequency to generate effective wall shear force while also controlling the start-stop time to achieve low-power intermittent operation.

[0056] The frame 8 of the rack and pinion linear reciprocating drive mechanism 1 is sealed to the central venous catheter 6 using any of the following methods: threaded connection, Luer lock connection, snap-fit ​​connection, magnetic connection, snap ring connection, or elastic sealing connection; the sealing connector 5 can be a plunger head, piston head, or ball head. The push rod 4 extends into the interior of the single-lumen central venous catheter 6 via a detachable connector 9. The axial reciprocating motion of the push rod 4 can be transmitted to the distal end of the single-lumen central venous catheter 6 via the liquid medium (preferably physiological saline) within the central venous catheter 6, thereby achieving the anticoagulant effect required by the anticoagulant central venous catheter device for hemodialysis of the present invention.

[0057] A fitting gap 10 is formed between the outer periphery of the sealing connector 5 and the inner wall of the central venous catheter 6. In this embodiment, the thickness of the fitting gap 10 is controlled to be 0.01 to 0.05 mm, and the axial length is 1.0 mm to 15.0 mm; preferably, the ratio of the axial length to the thickness of the fitting gap is controlled to be 50-300:1. This fitting gap 10 can ensure that the push rod 4 can smoothly perform axial reciprocating motion, avoiding the problem of excessive friction caused by excessively long seals, and can also form sufficient fluid resistance to ensure that the stable periodic excitation energy is efficiently transmitted to the distal end along the catheter axis, rather than leaking from the gap. This generates a wall shear force on the inner wall of the catheter that inhibits thrombus formation, preventing leakage of blood or dialysate from the catheter. The non-thermal wall shear force of this invention can directly interfere with the activation and adhesion of platelets and the aggregation of fibrin networks in the early stage of thrombus formation, thereby achieving source blocking and continuous inhibition of key thrombus precursors at the physical level.

[0058] In this embodiment, the frame 8 of the rack and pinion linear reciprocating drive mechanism 1 can be controlled to have a maximum external size of no more than 60mm×30mm×30mm and a weight of no more than 50g, so that the system of the present invention can be stably and comfortably attached to the patient's body surface, and allow the patient to carry out daily activities and dress freely during treatment, thereby achieving wearable continuous active thrombosis prevention.

[0059] When using the anticoagulant central venous catheter device based on rack and pinion vibration, one end of the central venous catheter 6 is fixed to the frame 8 of the rack and pinion linear reciprocating drive mechanism 1 via the detachable connector 9. The push rod 4 extends into the central venous catheter 6, and the outer periphery of the sealing connector 5 at the front end of the push rod 4 forms a fitting gap 10 with the inner wall of the central venous catheter 6. First, the positions of the two limit switches 19 in the frame adjustment groove are slid and adjusted and locked. The reciprocating limit stroke of the push rod is limited by the distance between the two limit switches, thereby setting the vibration intensity amplitude. Then, the speed and start / stop of the drive motor 11 are adjusted, and the drive gear 2 rotates alternately in the forward and reverse directions, thereby driving the transmission rack 3 to make a smooth periodic reciprocating motion along the upper surface of the guide rail 20. The push rod 4 moves synchronously with the transmission rack. The sealing connector 5 drives the saline solution in the lumen of the central venous catheter to reciprocate, converting mechanical vibration into a stable periodic vibration force acting on the fluid in the central venous catheter; this shear force can directly interfere with the aggregation of platelets and fibrin in the early stage of thrombosis, achieving physical-level source prevention.

[0060] Example 2

[0061] This embodiment addresses the clinical scenario of catheter indwelling between two hemodialysis sessions. Its goals are to replace traditional anticoagulant-based catheter sealing, avoid drug side effects, prevent in-catheter thrombosis, and extend the lifespan of central venous catheters. Fluid dynamics simulation is used to test the anticoagulant effect of a central venous catheter device based on rack and pinion vibration during saline injection. In this embodiment, the cardiac venous catheter 6 has a total length of 190mm and an inner diameter of 3.6mm; the clearance 10 between the sealing connector 5 and the inner wall of the central venous catheter 6 is 0.02mm, and the axial length of the sealing connector 5 is 5mm. The reciprocating motion amplitude of the control push rod is 3cm, and the voltage controlled by the voltage adjustment module 13 is 3.5V~5.8V for simulation, corresponding to a push rod vibration frequency of 1.4Hz~3.3Hz, adapted to the working characteristics of a small drive motor, balancing clinical anticoagulant effect with the device's low-power operation requirements. This simulation tested the steady-state excitation effect for a single 30-second cycle. The periodic start-stop function was not enabled; therefore, the time control relay was only set to operate for 30 seconds, running continuously without interruption. In clinical applications, the time control relay can be independently set to operate and pause within the range of 0.1 seconds to 72 hours to achieve intermittent operation and reduce overall energy consumption. This simulation selected three typical excitation cycles: 0.2 seconds, 0.25 seconds, and 0.3 seconds. The excitation cycle is defined as the time required for the drive motor to complete one revolution, with the frequency being the reciprocal of the cycle. The corresponding excitation frequencies are approximately 5Hz, 4Hz, and 3.3Hz, respectively, and the corresponding drive motor supply voltages are approximately 5.8V, 4.6V, and 3.5V.

[0062] The 3D geometric model of the catheter and blood vessel was constructed using ANSYS Design Modeler, and mesh generation was performed using FluentMeshing. Solving and post-processing were both completed on the ANSYS Fluent platform. Simulation parameters such as material properties, boundary conditions, excitation period, and motion amplitude were set using ANSYS Fluent. The simulated medium inside the central venous catheter was physiological saline, and the medium in the vascular domain was blood. The total simulation duration was set to 30 seconds. Based on the above-mentioned simulation conditions and boundary conditions, the wall shear force-time data for different axial positions of the catheter at an excitation period of 0.25 seconds were extracted using the fluid dynamics simulation solution and the ANSYS CFD Post post-processing module. The wall shear force-time curves for each axial position of the catheter at an excitation period of 0.25 seconds were plotted using Origin software, as shown in Figures 5-8. Data from multiple excitation cycles corresponding to a 3cm excitation stroke were processed. Data from the initial 1-second injection of saline into the catheter were removed. The maximum and minimum values ​​of the catheter wall shear force at different axial positions within each cycle over a valid time period of 1–30 seconds were extracted. Using Origin software, curves showing the maximum and minimum values ​​of the catheter wall shear force as a function of position under a 3cm excitation stroke and different excitation cycles were plotted. Figure 9 At the simulation steady-state moment (t=30s), the wall shear force distribution along the entire axial length of the duct was extracted using ANSYS CFD Post. The axial transmission and distribution of shear force along the inner wall of the duct under different excitation cycles was displayed as a contour map. The contour maps of the duct wall shear force distribution corresponding to different excitation cycles were then integrated to obtain... Figure 10 The image shows the distribution cloud map of shear force on the guide tube wall under different excitation cycles (t=30s) with an excitation stroke of 3cm, corresponding to three typical excitation cycles of 0.2s, 0.25s, and 0.3s, respectively.

[0063] As shown in Figures 5-8, the four curves represent the wall shear force versus time variation curves at positions 10mm, 20mm, 30mm, and 40mm from the catheter tip under a 0.25s excitation cycle. As can be seen from the figures, under this excitation cycle, the wall shear force at different axial positions of the catheter exhibits regular and stable periodic fluctuations, without instantaneous impacts or abrupt numerical changes. The overall fluctuation amplitude is uniform, and the temporal sequence is consistent. Furthermore, as the distance from the catheter outlet increases, the peak wall shear force gradually decreases, but remains within the effective anticoagulation shear force range throughout. These figures clearly demonstrate that the mechanical excitation output of this invention is stable, the vibration timing is controllable, and the excitation effect can be uniformly transmitted through the saline medium inside the catheter. It can establish a stable and controllable shear force field on the inner wall and distal section of the catheter, verifying the rationality of the excitation structure and transmission matching scheme of this invention from a dynamic response perspective, and providing dynamic performance support for the feasibility of the scheme.

[0064] from Figure 9 As can be seen, the maximum and minimum values ​​of the wall shear force corresponding to each cycle are consistently within the safe and effective range of 0.5 Pa to 15 Pa required for clinical anticoagulation; simultaneously, they exhibit a monotonic variation pattern where the maximum and minimum wall shear forces gradually decrease as the excitation cycle increases. This pattern is clearly demonstrated in the graph. Based on the gear and rack transmission combined with the voltage adjustment module and limit switch of this invention, the motor speed can be changed by adjusting the power supply voltage, thereby continuously altering the excitation cycle. Combined with the limit switch, the push rod stroke can be freely adjusted, achieving dual continuous and precise control of the amplitude and cycle of the wall shear force. This can adapt to the indwelling conditions of different catheter specifications, demonstrating good parameter adjustability and adaptability to operating conditions, further proving the feasibility of this invention for clinical application.

[0065] from Figure 10 The cloud map showing the shear force distribution on the catheter wall under different excitation cycles demonstrates that the periodic mechanical excitation energy can be smoothly transmitted along the catheter axis to the distal tip. The overall shear force distribution on the inner wall is continuous and uniform, with only slight axial attenuation. Furthermore, the shear force value decreases systematically with increasing excitation cycle. Under the three conditions of 0.20s, 0.25s, and 0.30s, the shear force across the entire range is above 1 Pa, consistently remaining within the safe anticoagulation range of 0.5 Pa to 15 Pa. This cloud map characteristic indicates that the present invention has high excitation energy transfer efficiency and a balanced effect across the entire range, enabling controllable physical anticoagulation throughout the catheter's operation.

[0066] As can be seen from the simulation results of Example 2, the vibration effect of the anticoagulation central venous catheter device based on gear and rack meshing vibration of the present invention is stable and controllable, and the anticoagulation effect is stable throughout the entire range. It can effectively replace traditional anticoagulant catheter sealing, meet the thrombosis prevention needs during the indwelling period of hemodialysis catheters, and has good clinical application feasibility and practicality. Compared with a previously applied anticoagulation central venous catheter system based on vibration force, the present invention, by adopting a gear and rack meshing linear reciprocating drive mechanism, achieves continuous and direct adjustment of the push rod reciprocating stroke, reduction of overall size, and simplification of assembly process while maintaining the basic vibration anticoagulation function, which has obvious advantages for portable central venous catheters.

[0067] Based on the two embodiments above, it should be emphasized that the central venous catheter of the present invention can be either single-lumen or multi-lumen, such as a dual-lumen central venous catheter (a central venous catheter with two independent lumens) or a triple-lumen central venous catheter. When the central venous catheter is multi-lumen, the rack and pinion linear reciprocating drive mechanism can communicate with at least one lumen, and preferably, the rack and pinion linear reciprocating drive mechanism can simultaneously communicate with multiple lumens of the central venous catheter. For example, for a dual-lumen central venous catheter, if simultaneous anticoagulation of both lumens is required, two independent rack and pinion linear reciprocating drive mechanisms should be configured, each driving one lumen. The connection method is the same as the aforementioned technical measures, with each rack and pinion linear reciprocating drive mechanism driving one lumen to achieve simultaneous anticoagulation of multiple lumens.

[0068] Based on the above implementation method, it is evident that, for existing pulse-type central venous catheters, this invention achieves controllable excitation through smooth reciprocating motion, realizing efficient transmission of excitation energy. Furthermore, by adjusting the fit gap 10 between the sealing connector and the catheter inner wall, a continuous and uniform non-thermal wall shear force is formed, ultimately achieving drug-free, non-invasive, and wearable thrombosis prevention. This measure highly integrates excitation generation, energy transmission, mechanical anticoagulation, and micro-wearability, significantly improving the accuracy of anticoagulation control and clinical applicability. The overall technical solution and physical anticoagulation mechanism are protected, rather than the specific structural form of the non-linear reciprocating drive mechanism. If the fit gap 10 between the sealing connector and the catheter inner wall is too small, it will increase frictional resistance, easily causing the push rod to jam and affecting excitation stability; if it is too large, it will lead to radial leakage of excitation energy, reducing energy transmission efficiency. This invention discovers that controlling the thickness of the mating gap to be 0.01-0.05 mm and the axial length of the mating gap to be 1.0 mm-15.0 mm, which conforms to the principle of slit flow, creates a highly efficient excitation energy transfer interface. This interface can ensure smooth push rod movement while minimizing energy loss, suppressing the attenuation of excitation energy transmission in long catheters, ensuring efficient directional transmission of excitation force, and suppressing radial leakage of excitation energy, ensuring that the energy is efficiently transmitted to the distal end along the catheter axis. It can also form a stable dynamic sealing interface, further improving the transmission efficiency of excitation energy and ensuring that the excitation effect is stably applied to the fluid inside the central venous catheter.

[0069] Meanwhile, this invention uses physiological saline instead of anticoagulants, achieving drug-free treatment and avoiding the bleeding risk associated with anticoagulants; it proactively prevents thrombosis from the source, overcoming the limitations of traditional drug anticoagulation and avoiding structural modifications to the catheter, effectively solving the problem of central venous catheter thrombosis and avoiding the side effects of traditional drug anticoagulation; moreover, its miniaturized, wearable, integrated, and long-term indwelling design does not affect the patient's mobility during indwelling and does not rely on medical staff; this invention forms a stable, continuous, and controllable periodic wall shear force, and the excitation parameters can be quantified and adjusted to achieve precise anticoagulation intervention.

[0070] This invention achieves controllable frequency and duration of the push rod's reciprocating motion through precise adjustment of the motor speed by a control unit, solving the problem of quantitative control of excitation time and cycle. In particular, by adjusting the axial distance between the two limit switches, the push rod's reciprocating stroke can be limited, allowing for flexible setting of the push rod's reciprocating amplitude and thus precise setting of the amplitude of a single stable excitation. The preferred adjustable reciprocating stroke range of the push rod is 1cm to 3cm. This amplitude value is suitable for the structural constraints and clinical requirements of wearable small devices, ensuring that the excitation energy is fully applied to the saline solution within the catheter to form an effective wall shear force that meets anticoagulation needs, while avoiding problems such as excessive device size, excessive mechanical vibration, and high power consumption caused by excessive amplitude. This invention can control the formation of a controllable wall shear force within the safe range of 0.5Pa to 15Pa on the inner wall of a central venous catheter, effectively inhibiting platelet adhesion, aggregation, and fibrin deposition, while avoiding biocompatibility risks caused by excessive shear force. This achieves the application goals of replacing anticoagulants for catheter sealing, inhibiting thrombus formation, and extending catheter lifespan.

[0071] The excitation frequency of the push rod in this invention is in the range of 1 Hz to 100 Hz, so as to ensure effective inhibition of thrombus formation while avoiding the risk of hemolysis and excessive power consumption of the device caused by excessive frequency.

[0072] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the various embodiments of the present invention.

Claims

1. An anticoagulant central venous catheter device based on gear and rack meshing vibration, characterized in that, The device includes a rack and pinion linear reciprocating drive mechanism and a central venous catheter. The push rod in the rack and pinion linear reciprocating drive mechanism extends into the central venous catheter, which is filled with saline solution. The front end of the push rod is connected to a sealing connector, and the outer periphery of the sealing connector forms a mating gap with the inner wall of the central venous catheter. The thickness of the mating gap is 0.01-0.05 mm, and the axial length is 1.0-15.0 mm. The rear end of the push rod is connected to the front end of a transmission rack. A drive motor is fixedly connected to a drive gear via its output shaft, and the drive gear meshes with the transmission rack. The transmission rack is slidably mounted on a guide rail. A limit switch is provided at the tail of the transmission rack, and two limit switches are separately and movably mounted on the side of the guide rail along its length. The limit switch is movably connected to the two limit switches. The drive motor is electrically connected to a voltage regulation module, a rechargeable battery, a time control relay, and the two limit switches.

2. The anticoagulant central venous catheter device based on rack and pinion vibration according to claim 1, characterized in that, The guide rail is located at the bottom of the frame along the extension direction of the push rod; the limit switch is movably installed in the adjustment groove via a sliding locking seat, and the adjustment groove is located on the inner wall of the frame.

3. The anticoagulant central venous catheter device based on rack and pinion vibration according to claim 2, characterized in that, The limit switch is a mechanical contact type limit switch; the adjustment groove is a non-through straight groove; the frame is a sealed cavity structure; the drive gear, transmission rack, push rod, sealing connector, guide rail, limit lever, two limit switches, drive motor, voltage regulation module, rechargeable battery, and time control relay are all located inside the cavity; the maximum external dimensions of the frame do not exceed 60mm×30mm×30mm.

4. The anticoagulant central venous catheter device based on rack and pinion vibration according to any one of claims 1-3, characterized in that, The guide rail is a long, single-rail structure with an inverted T-shaped or I-shaped cross-section, and the top of the guide rail is a finely ground flat surface; the bottom of the transmission rack is provided with a groove, and the top of the guide rail is set in the groove; the rear end of the push rod is connected to the front end of the transmission rack by any one of the following methods: threaded connection, pin connection, interference fit, or adhesive bonding.

5. The anticoagulant central venous catheter device based on rack and pinion vibration according to claim 2, characterized in that, The frame is provided with a detachable connector at its end, and the frame is sealed to the end of the central conduit through the detachable connector.

6. The anticoagulant central venous catheter device based on rack and pinion vibration according to claim 1, characterized in that, The distance between the two limit switches in the length direction is 1cm to 3cm.

7. The anticoagulant central venous catheter device based on rack and pinion vibration according to claim 1, characterized in that, The drive motor is fixedly connected to the drive gear through the motor output shaft passing through the motor shaft mounting hole on the drive gear; the sealing connector is a plunger head, piston head, or ball head; the sealing connector is made of a biocompatible elastic material; the gear and rack linear reciprocating drive mechanism also includes a charging port and a power switch, the charging port being electrically connected to the rechargeable battery; the power switch and the rechargeable battery are connected via an internal connecting wire.

8. The anticoagulant central venous catheter device based on rack and pinion vibration according to claim 7, characterized in that, The sealing connector is made of medical-grade silicone, medical-grade polyurethane, or fluororubber; the rechargeable battery is also electrically connected to the voltage regulation module, the time control relay, and the two limit switches.

9. The anticoagulant central venous catheter device based on rack and pinion vibration according to claim 1, characterized in that, Multiple rack and pinion linear reciprocating drive mechanisms are provided, and each rack and pinion linear reciprocating drive mechanism is connected to a single cavity of the central venous catheter.

10. The anticoagulant central venous catheter device based on rack and pinion vibration according to claim 1, characterized in that, The overall weight of the rack and pinion linear reciprocating drive mechanism does not exceed 50g. The ratio of the axial length to the thickness of the fitting clearance is controlled within (50-300):1.

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