Needle stick injury prevention syringe

Abstract

This invention discloses a needlestick-proof syringe, comprising a syringe barrel, a needle hub, a piston head, and a needle. The syringe barrel has a liquid reservoir, and a connecting structure detachably connects the syringe barrel and the needle hub. The needle hub has a liquid outlet chamber, which connects to an opening on the top wall of the needle hub for the needle to pass through. A needle disc is coaxially connected to the end of the needle, and the needle disc is movably disposed in the liquid outlet chamber. The liquid outlet chamber has a limiting structure for restricting the sliding of the needle disc along the needle hub axis when the needle disc is not axially rotating. The piston head has an unlocking structure for driving the needle disc to rotate axially to release the limiting structure from restricting the needle disc. The liquid outlet chamber has a loading structure for applying a force towards the liquid reservoir to the needle disc when the limiting structure releases its restriction on the needle disc. This invention solves the problem of needlestick injuries that occur when medical personnel manually remove the needle after injection, which is common in traditional syringes.

Description

Technical Field

[0001] This invention relates to the field of syringe technology, specifically to a needle-puncture-proof syringe. Background Technology

[0002] Injection syringes are among the most commonly used medical devices in clinical diagnosis and treatment, and are widely used in various drug administration and blood collection procedures. However, the risk of needlestick injury in the post-use handling process has become one of the main causes of occupational exposure for medical staff.

[0003] Traditional syringes (including disposable and reusable types) leave the needle exposed after injection, requiring healthcare workers to manually remove, disassemble, or dispose of the needle. During this process, factors such as operator fatigue, obstructed vision, or accidental collisions can easily lead to needlestick injuries, potentially resulting in cross-infection of bloodborne infectious diseases such as hepatitis B and HIV, seriously threatening the occupational safety of healthcare workers.

[0004] Currently, most existing needlestick injury prevention technologies rely on passive protective caps or disposable self-destructing structures. The former still requires medical staff to manually put on the cap, failing to eliminate operational risks at the source; the latter is only applicable to disposable syringes, and its design often prevents the syringes from being reused, increasing medical costs and wasting resources. Furthermore, some protective structures suffer from insufficient reliability and are prone to accidental triggering, making it difficult to reliably provide protection in clinical settings. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a needle-puncture-proof syringe, which solves the problem that traditional syringes require manual disassembly of the needle by medical personnel after injection, making needle punctures easy to occur during needle handling.

[0006] To achieve the above objectives, the present invention provides a needle-puncture-proof syringe, comprising a syringe barrel, a needle hub, a piston head, and a needle disposed on the needle hub. The syringe barrel has a reservoir for filling with external medication. The piston head is slidably disposed in the reservoir and is connected to a piston rod for passing through the reservoir. A connecting structure is detachably connected between the syringe barrel and the needle hub. The needle hub has an outlet chamber for communicating with the reservoir. The outlet chamber is connected to an opening formed on the top wall of the needle hub for the needle to pass through. A needle disc is coaxially connected to the end of the needle. The needle disc is movably disposed in the outlet chamber. The outlet chamber is provided with a limiting structure for restricting the sliding of the needle disc along the axis of the needle hub when the needle disc is not axially rotated. The piston head is provided with an unlocking structure for driving the needle disc to rotate axially to release the limiting structure from restricting the needle disc. The outlet chamber is provided with a loading structure for applying a force toward the reservoir to the needle disc when the limiting structure releases the limiting structure from restricting the needle disc.

[0007] The advantages of adopting the above technical solution are as follows: The detachable connection structure between the syringe and needle hub allows for flexible assembly and disassembly, adapting to the assembly and disassembly requirements of different usage scenarios; the interconnected design of the dispensing chamber and the reservoir chamber ensures smooth drug delivery along a preset path, meeting the drug flow requirements for normal injection; the coaxial connection between the needle disc and the needle tip enables synchronous movement, ensuring consistency in needle extension and rotation; the limiting structure restricts axial sliding of the needle disc when it is not rotating axially, preventing the needle from retracting due to external force or drug pressure during injection, ensuring stable needle extension and improving the accuracy of injection operations; and the unlocking structure allows the needle disc to rotate axially, achieving precise control of the limiting structure. Unlocking provides the necessary conditions for needle retraction. After the limit is released, the aforementioned loading structure applies a force towards the reservoir cavity of the needle disc, causing the needle disc and needle to retract automatically. This eliminates the need for medical personnel to manually contact the exposed needle, thereby eliminating the risk of needlestick injury at its source and improving occupational safety during medical procedures. Through the coordinated operation of these structures, structural stability is maintained during injection, and the protective action is automatically triggered after injection. This triggering requires no additional manual operation, improving the convenience of clinical use. The overall structure is compact, does not alter the conventional operation of the syringe, and is compatible with both disposable and reusable syringes. The stable connection and cooperation of each structure reduces the likelihood of accidental triggering or structural failure, ensuring the continuous reliability of the needlestick injury prevention effect. The needle in the above technology is existing technology, featuring an injection port for discharging medication. The needle disc is coaxial with the needle and integrally connected, with the injection port extending through the needle disc to form an inlet for medication to enter the injection port. Alternatively, the needle disc can be annular and fitted onto the outer peripheral wall of the needle tip. Since this is existing technology, its structure and function will not be described in detail further.

[0008] The present invention further comprises: the limiting structure including a plurality of limiting blocks arranged circumferentially on the inner peripheral wall of the liquid outlet cavity, the radial cross section of the limiting blocks being arc-shaped, the plurality of limiting blocks being evenly distributed along the circumferential direction on the inner peripheral wall of the liquid outlet cavity, and the top end face of the limiting block being a limiting surface for abutting and cooperating with the bottom wall of the needle plate.

[0009] The advantages of adopting the above technical solution are as follows: In the above technology, the limiting blocks are uniformly arranged circumferentially on the inner peripheral wall of the liquid outlet cavity, so that the needle plate is subjected to balanced circumferential force, which improves the stability of the axial sliding restriction of the needle plate and avoids circumferential displacement or local deformation of the needle plate during injection. This prevents the needle plate from axially sliding due to the push of the liquid or external vibration during injection, ensuring the effective injection stroke of the needle and ensuring that the needle is always in the coaxial injection position. The radial cross section of the limiting block is set in an arc shape, which has a higher degree of fit with the curved surface of the inner peripheral wall of the liquid outlet cavity, reduces stress concentration at the structural connection, improves the structural strength and wear resistance of the limiting block, and extends its service life. Moreover, the arc cross section design can also reduce the frictional resistance between the needle plate and the limiting block when the needle plate rotates axially, which facilitates the smooth rotation of the needle plate driven by the unlocking structure, ensures the smoothness of the unlocking action, makes the limiting constraint of the needle plate more comprehensive, prevents the needle plate from local warping, ensures the stability of the needle plate movement, and provides a structural basis for the precise alignment of the unlocking groove and the limiting block, thereby improving the accuracy of the unlocking action.

[0010] The present invention further comprises: a plurality of unlocking grooves passing through the needle plate; the plurality of unlocking grooves are evenly distributed along the circumferential direction on the needle plate and are positioned close to the edge of the needle plate; the number of the plurality of unlocking grooves corresponds one-to-one with the number of the plurality of limiting blocks; when the unlocking structure does not drive the needle plate to rotate axially, the unlocking grooves and the corresponding limiting blocks are misaligned.

[0011] The advantages of adopting the above technical solution are as follows: The unlocking grooves are evenly distributed along the circumference of the needle disc, achieving a one-to-one correspondence in number and position with the limiting blocks. This ensures that each unlocking groove can be synchronously and precisely aligned with the limiting blocks when the needle disc rotates, achieving synchronous release of the limiting structure. This avoids needle disc jamming due to partial unreleased limiting, ensuring smooth retraction. Furthermore, the unlocking grooves are positioned close to the edge of the needle disc, increasing the lever arm of the needle disc rotation and reducing the resistance to the unlocking structure driving the needle disc's rotation. This allows the needle disc to quickly complete axial rotation with a smaller driving force, improving the timeliness of the unlocking action. When the unlocking structure is not driven, the unlocking grooves and limiting blocks are offset, ensuring that the limiting blocks can stably abut against the bottom wall of the needle disc, effectively limiting the axial sliding of the needle disc. This prevents accidental alignment due to vibration, external forces, or other factors during injection, preventing abnormal needle retraction caused by limiting failure and ensuring smooth injection operations. The even distribution of the unlocking grooves ensures balanced circumferential force during needle disc rotation, avoiding localized stress concentration that could lead to needle disc deformation, and ensuring the structural integrity and motion stability of the needle disc.

[0012] The present invention further specifies that the radial cross-sectional area of ​​the unlocking groove is greater than the radial cross-sectional area of ​​the limiting block.

[0013] The advantages of adopting the above technical solution are: the radial cross-sectional area of ​​the unlocking groove is larger than that of the limiting block, which provides a reasonable gap for the limiting block to enter the unlocking groove, effectively compensating for dimensional errors during processing and assembly, improving the adaptability of the structure, avoiding jamming between the limiting block and the unlocking groove due to processing accuracy issues, ensuring the smooth release of the limit, and reducing the frictional contact area between the limiting block and the unlocking groove, reducing the frictional resistance between the two during the rotation and retraction of the needle plate, facilitating the loading structure to quickly drive the needle plate and needle tip to retract, improving the timeliness of the protective action, and reducing the contact time between medical personnel and the exposed needle tip.

[0014] The present invention further provides that: the number of the plurality of limiting blocks is three, and the three limiting blocks are arranged in a triangular distribution.

[0015] The advantages of adopting the above technical solution are: the number of limiting blocks in the above technology is preferably set to three and distributed in a triangle. By utilizing the structural stability of the triangle, the limiting constraint effect on the needle plate is greatly improved, making it less likely for the needle plate to rotate circumferentially or slide axially during injection, thus ensuring the coaxial stability of the needle and the accuracy of injection. At the same time, the triangular distribution of the three limiting blocks forms a stable support structure at the stress point of the bottom wall of the needle plate, preventing the needle plate from warping or swaying locally, and ensuring the smooth movement of the needle plate.

[0016] The present invention further comprises: the unlocking structure including a plurality of contacts disposed on the top wall of the piston head, and a plurality of unlocking holes being provided on the bottom wall of the needle plate, wherein the plurality of contacts are disposed in a one-to-one correspondence with the plurality of unlocking holes, and each contact is inserted into its corresponding unlocking hole when the piston head slides and approaches the needle seat.

[0017] The advantages of adopting the above technical solution are: the contacts of the unlocking structure are set one-to-one with the unlocking holes on the bottom wall of the needle plate, realizing precise transmission between the piston head and the needle plate, ensuring that the driving force can be evenly transmitted to all parts of the needle plate when the piston head slides, so that the needle plate is subjected to balanced force in the circumference, avoiding swaying or jamming during rotation, and ensuring the smoothness of the unlocking action. Moreover, the contacts are set on the top wall of the piston head and move synchronously with the sliding of the piston head, so that the unlocking action is linked with the injection action. When the piston head slides to the limit position after the injection is completed, the unlocking is automatically triggered, without the need for additional manual operation by medical staff, improving the convenience of clinical use, and avoiding the operational risks caused by manual unlocking.

[0018] The present invention further comprises: the loading structure including a loading spring disposed in the liquid outlet cavity, the loading spring being disposed around the needle tip, the starting end of the loading spring being coaxially connected to the bottom wall of the liquid outlet cavity, and the ending end of the loading spring being coaxially connected to and abutting against the top wall of the needle plate.

[0019] The advantages of adopting the above technical solution are: the loading spring is located on the periphery of the needle tip, making full use of the internal space of the liquid outlet cavity, making the internal structure layout of the needle seat more compact, without increasing the overall volume of the needle seat. The loading spring is coaxially connected and abuts against the bottom wall of the liquid outlet cavity and the top wall of the needle plate, so that the elastic force of the spring is applied along the axis of the needle seat, ensuring that the needle plate is subjected to balanced force, avoiding the needle plate from swaying or tilting during the retraction process, ensuring that the needle tip retracts smoothly along the axis, and improving the smoothness of the retraction action.

[0020] The present invention further comprises: a sealing sleeve provided in the liquid outlet chamber, the sealing sleeve being fitted onto the outer peripheral wall of the needle and positioned near the connection between the needle and the needle disc; the sealing sleeve being made of medical-grade silicone rubber; a loading spring being positioned around the sealing sleeve; the top wall of the sealing sleeve being coaxially connected to the bottom wall of the liquid outlet chamber; a mating ring being provided on the top wall of the needle disc, the mating ring being fitted onto the outer peripheral wall of the needle and positioned at the connection between the needle and the needle disc; the inner peripheral wall of the shaft hole of the loading spring being positioned at the junction with the outer peripheral wall of the mating ring; the bottom wall of the sealing sleeve being abutting against the top wall of the mating ring; and the inner peripheral wall of the shaft hole of the loading spring being positioned with a clearance fit against the outer peripheral wall of the sealing sleeve.

[0021] The advantages of adopting the above technical solution are as follows: The sealing sleeve is made of medical-grade silicone rubber, which has excellent elastic sealing performance. It can tightly fit the outer peripheral wall of the needle, effectively blocking the leakage of the liquid medicine from the gap between the needle and the perforation, ensuring the sealed transmission of the liquid medicine, and avoiding waste and contamination. The sealing sleeve is placed at the connection between the needle and the needle plate, providing targeted sealing for this critical part that is prone to gaps, improving the overall sealing effect of the syringe and meeting the sealing requirements of medical devices. The loading spring is located on the periphery of the sealing sleeve, avoiding structural interference between the spring and the sealing sleeve and the needle, ensuring the independent movement of each structure. At the same time, the outer layout of the spring can provide a certain degree of protection for the sealing sleeve, preventing the sealing sleeve from being deformed by external forces. Furthermore, the inner peripheral wall of the loading spring shaft hole is connected to the outer peripheral wall of the mating ring, so that the mating ring guides the extension and contraction of the spring, preventing the spring from swaying during extension and contraction, ensuring that the spring force is transmitted along the axial direction, and improving the smoothness of the needle plate retraction.

[0022] The present invention further comprises: a groove circumferentially formed on the inner peripheral wall of the liquid outlet chamber, a sealing ring disposed in the groove, a sealing lip extending from the inner peripheral wall of the shaft hole of the sealing ring toward the opening of the groove, the sealing lip being annularly arranged, the radial cross-section of the sealing lip being trapezoidal and the sealing lip being disposed within the liquid outlet chamber, the top wall of the needle plate being connected to the outer peripheral wall of the needle plate with a smooth curved surface forming a first stepped surface, the bottom wall of the sealing lip being connected to the inner peripheral wall of the shaft hole of the sealing lip with a smooth curved surface forming a second stepped surface, the first stepped surface and the second stepped surface being in contact with each other, and the sealing ring being made of medical-grade silicone rubber.

[0023] The advantages of adopting the above technical solution are as follows: In the above technology, the sealing ring is embedded in the groove on the inner peripheral wall of the liquid outlet chamber. The groove provides circumferential and axial restraint for the sealing ring, preventing displacement or detachment of the sealing ring during the rotation or retraction of the needle disc, thus ensuring the stability of the sealing effect. The sealing lip of the sealing ring extends towards the opening of the groove and is arranged in a ring shape, making close contact with the first step surface of the needle disc to form a lip-shaped sealing structure. The elastic deformation capability of the sealing lip improves the fit with the needle disc, effectively blocking the gap between the liquid outlet chamber and the outside, preventing the liquid from overflowing and external impurities from entering the liquid outlet chamber, ensuring the cleanliness of the liquid and the efficiency of the liquid transmission. In addition, the radial cross section of the sealing lip is trapezoidal, which has good elastic recovery performance, can adapt to the rotation and retraction of the needle disc, and always maintains close contact with the needle disc, improving the reliability of the seal.

[0024] The present invention further comprises: a connecting sleeve integrally connected to the end of the needle seat; the liquid outlet chamber communicating with the connecting sleeve and forming a connecting hole; the inner peripheral wall of the connecting sleeve and the inner peripheral wall of the liquid outlet chamber forming a smooth curved surface and forming a third stepped surface; the diameter of the connecting hole being larger than the diameter of the liquid outlet chamber; the diameter of the connecting sleeve being larger than the diameter of the needle seat; the beginning end of the syringe coaxially connected with a connecting nozzle integrally connected; the liquid storage chamber communicating with the end wall of the connecting nozzle forming a through hole; the connecting structure including a first threaded groove circumferentially formed on the inner peripheral wall of the connecting hole and a second threaded groove circumferentially formed on the outer peripheral wall of the connecting nozzle; the first threaded groove and the second threaded groove being threadedly connected to realize the connection between the connecting sleeve and the connecting nozzle; when the first threaded groove and the second threaded groove are threadedly connected, the top wall of the connecting nozzle and the third stepped surface are abutted and fitted.

[0025] The advantages of adopting the above technical solution are as follows: In the above technology, the diameter of the connecting hole is larger than the diameter of the liquid outlet chamber, and the diameter of the connecting sleeve is larger than the diameter of the needle seat. The third step surface formed by this fits against the top wall of the connecting nozzle, achieving precise axial positioning when the syringe and needle seat are connected, ensuring coaxial communication between the liquid storage chamber and the liquid outlet chamber, improving the smoothness of drug delivery, and avoiding drug residue or obstruction due to chamber misalignment; The first threaded groove and the second threaded groove of the connecting structure are threadedly connected, realizing a detachable connection between the syringe and the needle seat, which facilitates needle replacement, needle seat cleaning and disinfection, and structural maintenance, and is suitable for disposable and reusable use; The threaded connection has a high tightness, which can effectively prevent the drug from overflowing from the connection gap between the syringe and the needle seat, improve the overall sealing effect of the syringe, and avoid drug waste and contamination. Attached Figure Description

[0026] Figure 1 This is a three-dimensional view of the invention in its unused state; Figure 2 for Figure 1 A sectional view; Figure 3 This is an exploded three-dimensional view of the present invention; Figure 4 This is a three-dimensional view of the invention in use. Figure 5 for Figure 4 A sectional view; Figure 6 This is a partial three-dimensional view of the needle holder and its linkage structure in this invention; Figure 7 This is a three-dimensional view of the piston head and its linkage structure in this invention. Detailed Implementation

[0027] This invention provides a needle-puncture-proof syringe, comprising a syringe barrel 1, a needle holder 2, a piston head 3, and a needle 4 disposed on the needle holder 2. The syringe barrel 1 has a reservoir 11 for infusing external medication. The piston head 3 is slidably disposed in the reservoir 11, and a piston push rod 31 for passing through the reservoir 11 is connected to the piston head 3. A detachable connection structure connects the syringe barrel 1 and the needle holder 2. The needle holder 2 has an outlet chamber 21 communicating with the reservoir 11. The outlet chamber 21 connects to a through-hole 211 formed on the top wall of the needle holder 2 for the needle 4 to pass through. A needle disc 41 is coaxially connected to the end of the needle 4. The needle disc 41 is movably disposed in the outlet chamber 21, and the outlet chamber 21 has a feature for preventing axial rotation of the needle disc 41. The device includes a limiting structure for the needle disc 41 to slide along the axis of the needle seat 2. The piston head 3 is equipped with an unlocking structure for driving the needle disc 41 to rotate axially to release the limiting structure's restriction on the needle disc 41. The liquid outlet chamber 21 is equipped with a loading structure for applying a force towards the liquid storage chamber 11 to the needle disc 41 when the limiting structure releases its restriction. The limiting structure includes several limiting blocks 22 circumferentially arranged on the inner wall of the liquid outlet chamber 21. The radial cross-section of each limiting block 22 is arc-shaped. These limiting blocks 22 are evenly distributed circumferentially on the inner wall of the liquid outlet chamber 21. The top end face of each limiting block 22 is a limiting surface for abutting against the bottom wall of the needle disc 41. Several unlocking grooves 411 penetrate the needle disc 41. A plurality of unlocking grooves 411 are evenly distributed along the circumferential direction on the needle plate 41, and the unlocking grooves 411 are positioned close to the edge of the needle plate 41. The number of the plurality of unlocking grooves 411 corresponds one-to-one with the number of the plurality of limiting blocks 22. When the unlocking structure does not drive the needle plate 41 to rotate axially, the unlocking grooves 411 and the corresponding limiting blocks 22 are misaligned. The radial cross-sectional area of ​​the unlocking grooves 411 is larger than the radial cross-sectional area of ​​the limiting blocks 22. The plurality of the plurality of limiting blocks 22 consists of three blocks, and the three limiting blocks 22 are arranged in a triangular pattern. The unlocking structure includes a plurality of contacts 32 disposed on the top wall of the piston head 3. A plurality of unlocking holes 412 are provided on the bottom wall of the needle plate 41, and the plurality of contacts 32 and the plurality of unlocking holes 412 are arranged one-to-one. When the piston head 3 slides and approaches the needle seat 2, each contact 32 is inserted into its corresponding unlocking hole 412. The loading structure includes a loading spring 23 disposed in the liquid outlet chamber 21. The loading spring 23 is located on the periphery of the needle head 4. The beginning of the loading spring 23 is coaxially connected to the bottom wall of the liquid outlet chamber 21, and the end of the loading spring 23 is coaxially connected to and abuts against the top wall of the needle plate 41. A sealing sleeve 24 is disposed in the liquid outlet chamber 21. The sealing sleeve 24 is sleeved on the outer peripheral wall of the needle head 4 and located near the connection between the needle head 4 and the needle plate 41. The sealing sleeve 24 is made of medical-grade silicone rubber. The loading spring 23 is located on the periphery of the sealing sleeve 24, and the top wall of the sealing sleeve 24 is coaxially connected to the bottom wall of the liquid outlet chamber 21.A mating ring 42 is provided on the top wall of the needle plate 41. The mating ring 42 is sleeved on the outer peripheral wall of the needle 4 and positioned at the connection between the needle 4 and the needle plate 41. The inner peripheral wall of the shaft hole of the loading spring 23 is positioned at the junction with the outer peripheral wall of the mating ring 42. The bottom wall of the sealing sleeve 24 is in abutting fit with the top wall of the mating ring 42. The inner peripheral wall of the shaft hole of the loading spring 23 is in a clearance fit with the outer peripheral wall of the sealing sleeve 24. A groove 25 is circumferentially formed on the inner peripheral wall of the liquid outlet chamber 21, and a sealing ring 251 is provided in the groove 25. The sealing ring 251 has a sealing lip 252 extending from the inner peripheral wall of its shaft hole toward the opening of the slot 25. The sealing lip 252 is annular and has a trapezoidal radial cross-section. The sealing lip 252 is located within the liquid outlet chamber 21. The top wall of the needle plate 41 and its outer peripheral wall are connected by a smooth curved surface, forming a first stepped surface 43. The bottom wall of the sealing lip 252 and the inner peripheral wall of its shaft hole are connected by a smooth curved surface, forming a second stepped surface 26. The first stepped surface 43 and... The second step surface 26 is in contact with the sealing ring 251, which is made of medical-grade silicone rubber. A connecting sleeve 27 is integrally connected to the end of the needle hub 2. The liquid outlet chamber 21 communicates with the connecting sleeve 27 and forms a connecting hole 271. The inner peripheral wall of the connecting sleeve 27 and the inner peripheral wall of the liquid outlet chamber 21 are smoothly curved and form a third step surface 272. The diameter of the connecting hole 271 is larger than the diameter of the liquid outlet chamber 21. The diameter of the connecting sleeve 27 is larger than the diameter of the needle hub 2. The beginning of the syringe 1 is coaxial and integrally connected with a connecting sleeve 27. The connector 12 has a through hole 121 formed on the end wall of the liquid storage chamber 11. The connection structure includes a first threaded groove 273 circumferentially formed on the inner peripheral wall of the connection hole 271 and a second threaded groove 13 circumferentially formed on the outer peripheral wall of the connector 12. The first threaded groove 273 and the second threaded groove 13 are threadedly connected to achieve the connection between the connecting sleeve 27 and the connector 12. When the first threaded groove 273 and the second threaded groove 13 are threadedly connected, the top wall of the connector 12 abuts against the third stepped surface 272.

[0028] Overall usage procedure for needle-puncture resistant syringes: Step 1 (Device Assembly): Detachably connect the needle holder to the syringe via the connecting structure. Tighten the first and second threaded grooves of the connecting sleeve and the connecting nozzle, so that the top wall of the connecting nozzle abuts against the third stepped surface, ensuring that the liquid storage chamber and the liquid outlet chamber are coaxially connected and sealed. At this time, the bottom wall of the needle plate abuts against the limiting surface of the limiting block, the unlocking groove is misaligned with the limiting block, the limiting structure restricts the needle plate from sliding along the axis of the needle holder, the loading spring is in a pre-compressed state, the needle tip passes through the through-hole on the top wall of the needle holder and remains in an extended state, completing the overall assembly of the device.

[0029] Step 2 (Drug Extraction): Insert the extended needle into the drug container, pull the piston rod backward, and move the piston head away from the needle seat in the storage chamber to create negative pressure in the storage chamber. The drug flows into the storage chamber through the needle and the outlet chamber in sequence. After extracting the preset dose of drug, pull the needle out of the drug container to complete the drug extraction.

[0030] Step 3 (Clinical Injection): Insert the needle into the patient's injection site, push the piston rod forward, and move the piston head towards the needle seat in the reservoir. The liquid in the reservoir is squeezed and injected into the patient through the outlet chamber and the needle. During the injection, the limiting structure continuously restricts the axial movement of the needle plate to prevent the needle from retracting due to the pressure of the liquid. The sealing lip of the sealing ring and the first step surface of the needle plate, and the sealing sleeve and the outer peripheral wall of the needle maintain a sealing fit to prevent the liquid from overflowing.

[0031] Step 4 (Unlock Trigger): When the piston rod is pushed to the end of the injection stroke and the liquid is completely ejected, the contact on the top wall of the piston head is precisely engaged with the unlocking hole on the bottom wall of the needle plate. Continue to push the piston rod, and the contact drives the needle plate to rotate axially along the needle seat axis through the unlocking hole until the unlocking groove on the needle plate is aligned with the limiting block in the liquid outlet chamber. The axial sliding restriction of the needle plate by the limiting structure is released.

[0032] Step 5 (Automatic Retraction Protection): After the limiting structure is unlocked, the pre-compressed loading spring releases its elastic force, pushing the needle plate along the needle seat axis toward the reservoir. The needle plate drives the coaxially connected needle to retract synchronously into the reservoir. At this time, medical staff can pull the piston rod to move the piston head, so that there is space in the reservoir to accommodate the needle until the needle is completely retracted into the reservoir, realizing automatic needle protection. During the retraction process, the cooperating ring guides the extension and retraction of the loading spring.

[0033] Step 6 (Disassembly and Disposal): After removing the needle from the patient's body, twist the needle hub and syringe in the opposite direction to disengage the first and second threaded grooves, thus separating the syringe from the needle hub. For single-use scenarios, dispose of the disassembled or whole device according to medical waste regulations. For reuse scenarios, clean and disinfect the syringe, replace it with a new needle and needle hub, and repeat the above steps to achieve reuse.

[0034] In this invention, the needle hub and all its internal linkage structures (including the needle disc, needle tip, loading spring, and limiting block) are pre-assembled as a single integrated unit before the needle hub leaves the factory. This assembly forms a complete needle hub assembly, eliminating the need for medical personnel to disassemble, reassemble, or adjust the internal structure of the assembly during clinical use. Medical personnel only need to perform one step before injection: detachably connect the pre-assembled needle hub assembly to the syringe via the threaded connection between the needle hub end connecting sleeve and the syringe barrel beginning nozzle. Tighten the threads until the top wall of the connecting nozzle abuts against the third step surface. This completes the syringe assembly and allows for drug extraction and injection. This pre-assembly design greatly simplifies clinical procedures for medical personnel, avoids complex internal assembly operations, reduces operational difficulty and intensity, fully meets the needs for rapid and convenient clinical use, and effectively avoids the risk of rejection due to cumbersome operation and insufficient practicality.

[0035] The accompanying drawings in the above-described technical specification are merely schematic views. The outlines, dimensions, proportions, and specific geometric shapes of the various components such as syringes, needle holders, needle discs, needles, limiting blocks, loading springs, sealing sleeves, and sealing rings shown in the drawings are not limited in any way. They are only used to clearly and intuitively illustrate the connection and fit relationships, relative positional relationships, and overall structural layout between the components, and are intended to assist in understanding the technical solution of the present invention. The scope of protection of the present invention is not limited by the visual presentation of the dimensions, shapes, etc. of the components in the accompanying drawings, and is subject to the explicit description in the claims.

[0036] The injection hole described in the above technology is identified as 44 in the accompanying drawings, and the inlet is identified as 441 in the accompanying drawings.

[0037] The foregoing has shown and described the basic principles and main features of the present invention, as well as its advantages. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the present invention. Various changes and modifications can be made to the present invention without departing from its spirit and scope. All such changes and modifications fall within the scope of the present invention as claimed, which is defined by the appended claims and their equivalents.

Claims

1. A needle-puncture-proof syringe, comprising a syringe barrel, a needle hub, a piston head, and a needle disposed on the needle hub, wherein the syringe barrel has a reservoir for infusing external medication, the piston head is slidably disposed in the reservoir and a piston rod for extending out of the reservoir is connected to the piston head, characterized in that: The syringe and the needle base are detachably connected by a connecting structure. The needle base has a liquid outlet chamber for communicating with the liquid storage chamber. The liquid outlet chamber is connected to a through-hole formed on the top wall of the needle base for the needle tip to pass through. The end of the needle tip is coaxially connected to a needle disc. The needle disc is movably disposed in the liquid outlet chamber. The liquid outlet chamber is provided with a limiting structure for restricting the sliding of the needle disc along the axis of the needle base when the needle disc does not rotate axially. The piston head is provided with an unlocking structure for driving the needle disc to rotate axially to release the limiting structure from restricting the needle disc. The liquid outlet chamber is provided with a loading structure for applying a force toward the liquid storage chamber to the needle disc when the limiting structure releases the limiting structure from restricting the needle disc.

2. The needle-puncture-proof syringe according to claim 1, characterized in that: The limiting structure includes a plurality of limiting blocks arranged circumferentially on the inner peripheral wall of the liquid outlet cavity. The radial cross-section of the limiting blocks is arc-shaped. The limiting blocks are evenly distributed along the circumferential direction on the inner peripheral wall of the liquid outlet cavity. The top end face of the limiting block is a limiting surface for abutting and cooperating with the bottom wall of the needle plate.

3. A needle-puncture-proof syringe according to claim 2, characterized in that: The needle plate has several unlocking slots that are evenly distributed along the circumference and are located near the edge of the needle plate. The number of unlocking slots corresponds one-to-one with the number of limiting blocks. When the unlocking structure does not drive the needle plate to rotate axially, the unlocking slots and the corresponding limiting blocks are misaligned.

4. A needle-puncture-proof syringe according to claim 3, characterized in that: The radial cross-sectional area of ​​the unlocking groove is set to be larger than the radial cross-sectional area of ​​the limiting block.

5. A needle-puncture-proof syringe according to claim 3, characterized in that: The number of the aforementioned limiting blocks is three, and the three limiting blocks are arranged in a triangular distribution.

6. A needle-puncture-proof syringe according to claim 2, characterized in that: The unlocking structure includes a plurality of contacts disposed on the top wall of the piston head, and a plurality of unlocking holes are provided on the bottom wall of the needle plate. The plurality of contacts are disposed in a one-to-one correspondence with the plurality of unlocking holes. When the piston head slides and approaches the needle seat, each contact is inserted into its corresponding unlocking hole.

7. A needle-puncture-proof syringe according to claim 1, characterized in that: The loading structure includes a loading spring disposed in the liquid outlet chamber. The loading spring is located around the needle tip. The beginning of the loading spring is coaxially connected to the bottom wall of the liquid outlet chamber, and the end of the loading spring is coaxially connected to and abuts against the top wall of the needle plate.

8. A needle-puncture-proof syringe according to claim 7, characterized in that: A sealing sleeve is provided in the outlet chamber. The sealing sleeve is fitted onto the outer peripheral wall of the needle and positioned near the connection between the needle and the needle disc. The sealing sleeve is made of medical-grade silicone rubber. The loading spring is positioned around the sealing sleeve. The top wall of the sealing sleeve is coaxially connected to the bottom wall of the outlet chamber. A mating ring is provided on the top wall of the needle disc. The mating ring is fitted onto the outer peripheral wall of the needle and positioned at the connection between the needle and the needle disc. The inner peripheral wall of the shaft hole of the loading spring is positioned at the junction with the outer peripheral wall of the mating ring. The bottom wall of the sealing sleeve and the top wall of the mating ring are in abutting fit. The inner peripheral wall of the shaft hole of the loading spring and the outer peripheral wall of the sealing sleeve are in a clearance fit.

9. A needle-puncture-proof syringe according to claim 1, characterized in that: The inner peripheral wall of the liquid outlet chamber is provided with a groove, and a sealing ring is provided in the groove. A sealing lip extends from the inner peripheral wall of the shaft hole of the sealing ring toward the opening of the groove. The sealing lip is annular and has a trapezoidal radial cross-section. The sealing lip is located in the liquid outlet chamber. The top wall of the needle plate and the outer peripheral wall of the needle plate are connected by a smooth curved surface and form a first stepped surface. The bottom wall of the sealing lip and the inner peripheral wall of the shaft hole of the sealing lip are connected by a smooth curved surface and form a second stepped surface. The first stepped surface and the second stepped surface are in contact. The sealing ring is made of medical-grade silicone rubber.

10. A needle-puncture-proof syringe according to claim 1, characterized in that: The needle hub is integrally connected to a connecting sleeve at its end. The liquid outlet chamber is connected to the connecting sleeve and has a connecting hole. The inner circumferential wall of the connecting sleeve and the inner circumferential wall of the liquid outlet chamber are connected with a smooth curved surface and form a third stepped surface. The diameter of the connecting hole is larger than the diameter of the liquid outlet chamber, and the diameter of the connecting sleeve is larger than the diameter of the needle hub. The beginning end of the syringe is coaxial and integrally connected to a connecting nozzle. The liquid storage chamber is connected to the end wall of the connecting nozzle and has a through hole. The connecting structure includes a first threaded groove circumferentially opened on the inner circumferential wall of the connecting hole and a second threaded groove circumferentially opened on the outer circumferential wall of the connecting nozzle. The first threaded groove and the second threaded groove are threadedly connected to realize the connection between the connecting sleeve and the connecting nozzle. When the first threaded groove and the second threaded groove are threadedly connected, the top wall of the connecting nozzle and the third stepped surface are abutted and fitted.

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