A method of assembling a pre-filled syringe

Abstract

The present application belongs to the technical field of medical devices, and particularly relates to an assembling method of a pre-filled syringe. The assembling method comprises the following steps: S01. The needle sleeve is sleeved on the needle seat, and a camera is used to confirm whether the needle sleeve is pierced by the needle; S02. The sleeve pressing head is inserted into the protective cover to radially outwardly lift the stop hook, wherein the minimum inner diameter of the sleeve pressing head is greater than the maximum outer diameter of the needle sleeve; S03. The protective cover that has been inserted into the sleeve pressing head is sleeved on the needle seat; and S04. The sleeve pressing head is taken out from the protective cover. The method uses a sleeve to outwardly expand the protective cover from inside, avoids the risk that the protective cover is stuck on the needle sleeve or the needle seat after installation, and achieves the purpose of first installing the needle sleeve, using a camera to check whether the needle sleeve is pierced, and then installing the protective cover.

Description

Technical Field

[0001] This invention belongs to the field of medical device technology, and in particular relates to a method for assembling a pre-filled syringe. Background Technology

[0002] Pre-filled syringes are injection devices used in the medical field, integrating the functions of a syringe and a drug container. These syringes are pre-filled with medication during the manufacturing process, and the purity and efficacy of the medication are protected through sealing. The pre-filled design makes it more convenient and faster for healthcare professionals to use, reducing the time and steps required for medication preparation. Furthermore, because pre-filled syringes are for single use, the risk of cross-infection is avoided, improving patient safety. In addition, the strict sealing measures implemented during the manufacturing process effectively protect the purity and stability of the medication, extending its shelf life.

[0003] The main components of a pre-filled syringe include the syringe body, drug container, plunger, needle, and protective cap. The syringe body is typically made of transparent material, allowing healthcare professionals to clearly observe the dosage and consistency of the medication. The drug container is generally made of glass or plastic, with a capacity varying according to need, allowing for different dosages of medication. The plunger propels the medication into the needle for injection. The needle is used to administer the medication to the patient. The protective cap protects the needle before and after use for hygiene.

[0004] However, existing pre-filled syringes are often discarded carelessly after use, leaving the needle exposed, which is very dangerous. To solve the problem of exposed needles after syringes are discarded, operators often put the removed protective cap back on. However, this has many drawbacks. On the one hand, the protective cap is custom-made for the needle and has a small opening, making it difficult to reinsert after being removed. On the other hand, the process of reinstalling the cap can easily cause the needle to prick the operator's hand.

[0005] To address the aforementioned issues, a protective pre-filled syringe with a protective shield has been proposed on the market. The inventor has previously applied for an invention patent in the relevant field, specifically CN114642793A, which describes a pre-filled syringe with a front protective shield. The shield can be adjusted axially by pushing and pulling to expose the needle for injection and to cover the needle for disposal after injection, thus preventing needlestick injuries to others.

[0006] Regarding the assembly method of pre-filled syringe components, CN114652920A describes a method for assembling a pre-filled syringe component with a protective cover, specifically including the following steps:

[0007] S1. Insert the needle sleeve unit into the protective cover unit along the axial direction;

[0008] S2. Sleeve the protective cover unit with the needle sleeve unit onto the mounting part axially;

[0009] S3. Push the piston into the syringe;

[0010] S4. Insert the push rod onto the piston.

[0011] However, the above assembly method has a drawback: in step S2, the needle may puncture the needle sheath unit. This puncture generates a lot of rubber debris, which is unacceptable for medical applications because it disrupts the sterile environment. Typically, cameras are used on the production line to confirm whether the needle sheath has been punctured, and to promptly remove pre-filled syringes with punctured sheaths. However, with the protective cover unit obstructing view, it is difficult for workers to visually confirm whether the needle sheath unit has been punctured, making it impossible to promptly remove pre-filled syringes with punctured sheaths from the production line, thus creating a certain degree of medical or commercial risk.

[0012] In summary, there is a need for a pre-filled injection needle assembly method that can facilitate confirmation of whether the needle sheath has been punctured by the needle during the assembly process, and can also smoothly fit a protective cover over the needle sheath. Summary of the Invention

[0013] The purpose of this invention is to provide a method for assembling a pre-filled syringe. This method uses a sleeve to expand the protective cover from the inside out, avoiding the risk of the protective cover getting stuck on the needle sheath or needle hub during subsequent installation. This achieves the goal of first installing the needle sheath and using a camera to check for punctures before installing the protective cover.

[0014] The technical solution adopted by the present invention to solve the above problems is: a method for assembling a pre-filled syringe, wherein the pre-filled syringe includes:

[0015] Syringes are used to encapsulate liquids;

[0016] The needle hub is mounted on the distal end of the syringe.

[0017] A needle is mounted on the needle hub and communicates with the syringe to allow the liquid to flow;

[0018] A protective cover is at least partially fitted onto the syringe and at least partially fitted onto the needle hub;

[0019] A needle sleeve, at least partially fitted onto the needle hub, to fully fit the needle;

[0020] The protective cover has a radially inwardly tapering stop hook at its proximal end, which is used to push up the proximal end face of the needle seat;

[0021] The assembly method includes the following steps:

[0022] S01. Fit the needle sheath onto the needle hub and use a camera to confirm whether the needle sheath has been pierced by the needle;

[0023] S02. Insert the sleeve pressure head into the protective cover to radially push the stop hook outward, wherein the minimum inner diameter of the sleeve pressure head is greater than the maximum outer diameter of the needle sleeve;

[0024] S03. Slide the protective cover that has been inserted into the sleeve pressure head onto the needle seat;

[0025] S04. Remove the sleeve pressure head from the protective cover.

[0026] A further preferred technical solution is that the minimum inner diameter of the sleeve pressure head is greater than the maximum outer diameter of the needle sleeve.

[0027] A further preferred technical solution is that the minimum outer diameter of the sleeve pressure head is greater than the maximum outer diameter of the needle seat.

[0028] A further preferred technical solution is that the wall thickness of the sleeve pressure head is 50~70 mils.

[0029] A further preferred technical solution is that the near end of the protective cover is also provided with a cantilever for supporting the far end face of the needle seat.

[0030] A further preferred technical solution is that: the stop hook is provided with a cantilever groove, and the cantilever is disposed on the inner side of the far end of the cantilever groove.

[0031] A further preferred technical solution is that the protective cover has a shrink ring at its distal end for engaging the distal end face of the needle seat.

[0032] A further preferred technical solution is that the protective cover is provided with a cantilever hook at the far end for engaging the far end face of the needle seat.

[0033] A further preferred technical solution is that the sleeve pressure head material includes one or more combinations of polypropylene, polyethylene, and polystyrene.

[0034] A further preferred technical solution is that the distal end of the sleeve pressure head is also provided with a stop protrusion.

[0035] In summary, the present invention has the following advantages:

[0036] 1. By using a sleeve pressure head, the needle sheath can be installed first, followed by the protective cover. This allows for timely inspection of the needle sheath after it is fitted onto the needle hub to check for punctures by the needle, thus improving the yield rate of pre-filled syringes on the production line.

[0037] 2. The wall thickness of the sleeve is precisely defined to satisfy the functions of supporting the cantilever and the stop hook, and will not touch the needle sleeve during the sleeve connection process, thus avoiding the risk of the needle sleeve being punctured by the needle during secondary installation. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the needle sleeve being attached to the needle holder in step S01.

[0039] Figure 2 This is a schematic diagram of step S02 where the sleeve pressure head is aligned with the protective cover but not inserted.

[0040] Figure 3 This is a schematic diagram of inserting the sleeve pressure head into the protective cover in step S02.

[0041] Figure 4 This is a schematic diagram of step S03 where the protective cover, which has already been inserted into the sleeve pressure head, is fitted onto the needle seat.

[0042] Figure 5 This is a schematic diagram of removing the sleeve pressure head from the protective cover in step S04.

[0043] Figure 6 This is a schematic diagram of the protective cover in Example 1.

[0044] Figure 7 for Figure 6 A schematic diagram of the protective shield rotated 180°.

[0045] Figure 8 This is a schematic diagram of the protective cover in Example 2.

[0046] Figure 9 for Figure 8 A schematic diagram of the protective shield rotated 180°.

[0047] In the attached diagram, the components represented by each number are as follows: syringe 1, needle holder 2, needle 3, protective cover 4, needle sleeve 5, stop hook 402, cantilever groove 403, cantilever 404, contraction ring 405, cantilever hook 406, and stop protrusion 601. Detailed Implementation

[0048] 1. Distal end: refers to the end of the syringe and its components mounted on it in a normal manner that face the needle.

[0049] 2. Proximal end: refers to the end of the syringe and its components mounted on it in a normal manner that is furthest from the needle.

[0050] 3. Axis: refers to the line connecting the centroids of all cross sections of a component with symmetrical cross sections.

[0051] 4. Open: refers to the ability to expose the needle or needle sheath during the operation.

[0052] 5. Closure: refers to the ability to cover the needle or needle sheath during operation.

[0053] 6. Socketing: refers to the act of mounting component one on the outer surface of component two when the inner diameter of component one is larger than the outer diameter of component two.

[0054] 7. Setting: refers to any method used to join two parts together, such as bonding, snapping, welding, screwing, or placing.

[0055] 8. Lifting: This refers to component one applying force to component two, causing component two to move in the opposite direction to the position of component one.

[0056] 9. Minimum / Maximum Diameter: For components with a distinct axis, a cross-section is taken perpendicular to the axis. This cross-section is approximately circular or polygonal. The narrowest part of this cross-section is the minimum diameter of the component, and the corresponding widest part is the maximum diameter. The minimum diameter of any given cross-section should not exceed its maximum diameter.

[0057] The present invention will be further described in detail below with reference to the accompanying drawings.

[0058] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

[0059] Example 1:

[0060] This embodiment provides a method for assembling a pre-filled syringe, wherein the pre-filled syringe includes: a syringe barrel 1, a needle hub 2, a needle 3, a protective cover 4, and a needle sleeve 5, wherein the protective cover 4 is provided with a stop hook 402, a cantilever groove 403, a cantilever 404, and a contraction ring 405.

[0061] The minimum inner diameter of the sleeve pressure head 6 is greater than the maximum outer diameter of the needle sleeve 5.

[0062] The minimum outer diameter of the sleeve pressure head 6 is greater than the maximum outer diameter of the needle seat 2.

[0063] refer to Figure 1 This demonstrates the needle sleeve being fitted onto the needle hub in step S01, and also shows the basic structure of the pre-filled syringe, including:

[0064] Syringe 1, used to encapsulate liquid;

[0065] Needle hub 2 is installed at the distal end of the syringe 1;

[0066] The needle 3 is mounted on the needle holder 2 and communicates with the syringe 1 to allow the liquid to flow;

[0067] The needle sleeve 5 is at least partially fitted onto the needle base 2 so as to fully fit the needle 3.

[0068] refer to Figure 1 In step S01, the needle sheath 5 is fitted onto the needle hub 2 to completely cover the needle 3. This process is completed using existing automated production line equipment for pre-filled syringes. First, on the production line, both the syringe and needle sheath undergo pre-treatment steps such as cleaning and disinfection to ensure product hygiene and quality. Then, the syringe is positioned in a fixed location, typically controlled by a robotic arm or conveyor system. Next, the needle sheath is prepared, automatically supplied to the fitting device, usually via a feeding system or vibratory feeder. Following this is the fitting process; once both the syringe and needle sheath are ready, the fitting device precisely inserts the needle sheath into the needle portion of the syringe. This process may involve mechanical operations such as rotation and pressure to ensure a secure connection between the needle sheath and the syringe.

[0069] Specifically, after the needle sheath 5 is attached, the syringe undergoes a quality inspection to ensure that it has not been punctured by the needle 3. This inspection process uses a camera, a technology already in use. In this embodiment, one or more high-resolution industrial cameras are installed on the production line. These cameras are typically connected to image processing software and a control system. The syringe is positioned within the camera's field of view, usually controlled by a conveyor system or a robotic arm. The camera captures images of the needle tip of the syringe, including images from different angles and under different lighting conditions, to more comprehensively check the attachment of the needle sheath. The captured images are transmitted to image processing software for analysis. The software uses algorithms and pattern recognition techniques to detect whether the needle sheath has been punctured by the needle; for example, edge detection, shape matching, or color analysis can be used to identify anomalies. Based on the image processing results, the system determines whether the needle sheath of each syringe has passed the quality inspection. If an anomaly is detected, an alarm may be triggered or the defective product may be removed from the production line. Furthermore, the system typically records the inspection results for each syringe and generates statistical data for quality control and improvement.

[0070] refer to Figure 2 The diagram illustrates step S02, where the sleeve pressure head is aligned with the protective cover but not yet inserted. The protective cover 4 is at least partially fitted onto the syringe 1 and at least partially fitted onto the needle holder 2. A sleeve pressure head 6 is coaxially arranged with the protective cover 4 and can be inserted into it. The needle holder 2 has radially outwardly expanding ridges, which hinder the installation of the protective cover 4. The specific structure of the protective cover 4 is shown in [the diagram]. Figure 6As can be seen, the protective cover 4 has a radially inwardly tapering stop hook 402 at its proximal end, which is used to lift the proximal end face of the needle seat 2. The protective cover 4 also has a cantilever 404 at its proximal end for lifting the distal end face of the needle seat 2. The way in which the protective cover 4 achieves its function can be found in CN114642793A.

[0071] The radially outward expanding ridge of the needle holder 2 will obstruct the stop hook 402 or cantilever 404 of the protective cover 4 during installation, making the installation process of the protective cover 4 less smooth. Furthermore, the inwardly contracting stop hook 402 or cantilever 404 will contact the needle sleeve 5 during the fitting process, posing a risk that the needle 3 may puncture the needle sleeve 5. Therefore, the camera inspection of the needle sleeve 5 in step S01 becomes meaningless. Therefore, in this embodiment, before fitting the protective cover 4 onto the needle holder 2, refer to... Figure 3 First, the sleeve pressure head 6 is inserted into the protective cover 4 from the distal side, with the stop hook 402 and the cantilever 404's gentle surfaces facing the distal side. This allows the sleeve pressure head 6 to radially press the stop hook 402 and cantilever 404 outwards along their gentle surfaces during insertion. Furthermore, the minimum inner diameter of the sleeve pressure head 6 is greater than the maximum outer diameter of the needle sheath 5. Therefore, even if the sleeve pressure head 6 and the protective cover 4 are fitted together with the needle sheath 5, theoretically, the sleeve pressure head 6 will not make any contact with the needle sheath 5. That is, the needle sheath 5, which was not punctured in step S01, remains intact during the fitting process. Additionally, the minimum outer diameter of the sleeve pressure head 6 is greater than the maximum outer diameter of the needle base 2. The maximum outer diameter of the needle holder 2 is the maximum outer diameter of the radially outward-expanding convex ridge of the needle holder 2. When the minimum outer diameter of the sleeve pressure head 6 is greater than the maximum outer diameter of the needle holder 2, the stop hook 402 and cantilever 404 radially outward-pressed by the sleeve pressure head 6 will easily pass over the convex ridge, i.e., they will not be blocked by the needle holder 2. (Reference) Figure 4 Once the protective cover 4 is fully fitted onto the needle sleeve 5, the stop hook 402 can completely pass over the protruding part of the needle seat 2.

[0072] In addition, refer to Figure 4 When the length of the sleeve pressure head 6 is insufficient to directly contact the stop hook 402, although it can be seen in the figure that the sleeve pressure head 6 does not directly push the stop hook 402 radially outward, but only pushes the cantilever 404 radially outward, since the cantilever 404 is installed in the cantilever groove 403 provided on the stop hook 402, when the sleeve pressure head 6 pushes the cantilever 404 radially outward, it will also have a certain effect on the stop hook 402. However, when the length of the sleeve pressure head 6 can directly contact the stop hook 402, the sleeve pressure head 6 can contact both the stop hook 402 and the cantilever 404 at the same time, and it is no longer necessary to drive the stop hook 402 through the cantilever 404.

[0073] refer to Figure 5The diagram shows the process of removing the sleeve pressure head from the protective cover in step S04. After the protective cover 4 is fully fitted onto the needle sleeve 5, the sleeve pressure head 6 can be immediately pulled out to the distal end. At this time, the stop hook 402 and the cantilever 404 return to their original radially inward contraction state, so as to firmly engage with the proximal and distal sides of the protrusion of the needle seat 2, respectively.

[0074] In addition, refer to Figure 4 The sleeve head 6 is also provided with a stop protrusion 601 at the far end. The stop protrusion 601 is used to facilitate the movement of the sleeve head 6 and to prevent the sleeve head 6 from being fully inserted into the protective cover 4 during the insertion process, and thus unable to be pulled out in step S04.

[0075] Example 2

[0076] In this embodiment, the assembly method of the pre-filled syringe is basically the same as that in Embodiment 1, except that:

[0077] The protective cover 4 is equipped with a cantilever hook 406.

[0078] The wall thickness of the sleeve pressure head 6 is 50~70 mils.

[0079] The sleeve pressure head 6 is made of one or more of polypropylene, polyethylene, and polystyrene.

[0080] In this embodiment, the cantilever hook 406 engages with the protruding rib of the needle holder 2, preventing the protective cover 4 from fully extending onto the syringe 1. Its function is similar to the contraction ring 405, but the cantilever hook 406 also has an inward contraction tendency. When the sleeve pressure head 6 is inserted into the protective cover 4, it acts as a barrier. In this embodiment, the wall thickness of the sleeve pressure head 6 is 50-70 microns, ensuring sufficient strength without being excessively thick, so that it touches the needle sheath 5 upon insertion into the protective cover 4. Alternatively, the sleeve pressure head 6 can also be made of metal materials, such as stainless steel, to achieve a similar effect.

[0081] Example 3

[0082] In this embodiment, the assembly method of the pre-filled syringe as described in Embodiment 1 is used. The sleeve indenter 6 is made of stainless steel, and sleeve indenters 6 with different wall thicknesses are used for testing. The test results are shown in the table below:

[0083]

[0084] It can be seen that when the wall thickness of the sleeve pressure head 6 is 30 mils, although it will not contact the needle sleeve 5, its strength is insufficient to lift the stop hook 402 and the cantilever 404, and it will deform under the radial contraction force of the stop hook 402 and the cantilever 404. When the wall thickness of the sleeve pressure head 6 is 40 mils, although the strength of the sleeve pressure head 6 can lift the cantilever 404, its proximal strength is insufficient to lift the stop hook 402. When the wall thickness of the sleeve pressure head 6 is between 50 and 70 mils, the strength of the sleeve pressure head 6 can lift both the stop hook 402 and the cantilever 404 at the same time, and its inner side will not contact the needle sleeve 5. When the wall thickness of the sleeve pressure head 6 is 80 mils, although the strength of the sleeve pressure head 6 can lift both the stop hook 402 and the cantilever 404 at the same time, its wall thickness is too thick, so it will contact the needle sleeve 5 during insertion, which poses a risk of the needle 3 puncturing the needle sleeve 5.

[0085] Furthermore, the same or similar element symbols are used as far as possible in the accompanying drawings and description to refer to the same or similar parts or steps. The drawings are presented in a simplified form and are not drawn to scale. For convenience and clarity only, directional terms such as top, bottom, left, right, upward, above, above, below, behind, and front may be used to refer to the drawings. These and similar directional terms should not be construed as limiting the scope of this disclosure in any way.

Claims

1. A method for assembling a pre-filled syringe, wherein the pre-filled syringe comprises: Syringe (1), used to encapsulate liquid; The needle hub (2) is installed at the distal end of the syringe (1); A needle (3) is mounted on the needle holder (2) and communicates with the syringe (1) to allow the liquid to flow; The protective cover (4) is at least partially fitted onto the syringe (1) and at least partially fitted onto the needle hub (2); The needle sleeve (5) is at least partially fitted onto the needle seat (2) to fully fit the needle (3); The protective cover (4) is provided with a radially inwardly tapering stop hook (402) at its proximal end, which is used to push up the proximal end face of the needle seat (2); The assembly method is characterized by the following steps: S01. Put the needle sheath (5) on the needle seat (2) and use a camera to confirm whether the needle sheath has been pierced by the needle (3); S02. Insert the sleeve pressure head (6) into the protective cover (4) to radially push the stop hook (402) outward; S03. The protective cover (4) that has been inserted into the sleeve pressure head (6) is fitted onto the needle seat (2); S04. Remove the sleeve pressure head (6) from the protective cover (4); The minimum inner diameter of the sleeve pressure head (6) is greater than the maximum outer diameter of the needle sleeve (5); the minimum outer diameter of the sleeve pressure head (6) is greater than the maximum outer diameter of the needle seat (2); the wall thickness of the sleeve pressure head (6) is 50-70 mils.

2. The assembly method of a pre-filled syringe according to claim 1, characterized in that, The protective cover (4) is also provided with a cantilever (404) at the near end for supporting the far end face of the needle seat (2).

3. The assembly method of a pre-filled syringe according to claim 2, characterized in that, The stop hook (402) is provided with a cantilever groove (403), and the cantilever (404) is disposed on the inner side of the far end of the cantilever groove (403).

4. The assembly method of a pre-filled syringe according to claim 1, characterized in that, The protective cover (4) is provided with a shrink ring (405) at the far end for engaging the far end face of the needle seat (2).

5. The assembly method of a pre-filled syringe according to claim 1, characterized in that, The protective cover (4) is provided with a cantilever hook (406) at the far end for engaging the far end face of the needle seat (2).

6. The assembly method of a pre-filled syringe according to claim 1, characterized in that, The sleeve pressure head (6) is made of one or more of polypropylene, polyethylene, and polystyrene.

7. The assembly method of a pre-filled syringe according to claim 1, characterized in that, The sleeve pressure head (6) is also provided with a stop protrusion (601) at its far end.

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