A device for measuring the needle length of an auto-injector

Abstract

This utility model discloses a device for measuring the needle length of an auto-injector, comprising an upper structure and a lower structure, which are slidably connected by a sliding fit. The upper structure is a hollow frame structure with a limiting groove at the top for accommodating the tip of the auto-injector or the activation button. Upper support arms are located on both sides of the upper structure, and each upper support arm has a positioning hole and a connecting hole at its bottom. The lower structure includes a base with lower support arms on both sides. Each lower support arm has a longitudinal hollow groove, and the sliding fit is located within the hollow groove. The upper support arms slide along the trajectory of the hollow groove via the sliding fit. A receiving groove is located in the middle of the base. This utility model has a simple structure, is easy to operate, and has strong adaptability. It can support the complete activation process of a simulated three-step auto-injector, greatly improving the accuracy of needle length measurement in the early stages of research and development.

Description

Technical Field

[0001] This utility model relates to the field of medical device testing technology, and in particular to a device for measuring the needle length of an auto-injector. Background Technology

[0002] In the field of medical devices, the needle extension length of an autoinjector directly determines the depth of drug injection, which in turn affects the accuracy of the dosage. If the needle is too long, it can cause tissue damage to the patient; if it is too short, the drug will not reach the effective site of action. Therefore, accurate needle length measurement is a key link in ensuring medication safety and therapeutic effect. In this field, the needle length should meet the requirements of international medical device standards such as ISO 11608 for product performance verification to ensure product quality and safety.

[0003] Commonly used auto-injectors can be divided into two-step and three-step types based on the different activation steps. Two-step injectors typically complete activation injection in two steps: "removing the cap and pressing the protective cover," making their structure and operation relatively simple. Three-step injectors, however, require three steps in sequence: "removing the cap, pressing the protective cover, and pressing the activation button." While their multi-stage activation mechanism improves the safety and controllability of the injection process, it presents significant challenges in needle length measurement. On one hand, three-step injectors require fixing the pen body before pressing the activation button separately, placing higher demands on the clamping stability and operational coordination of the testing fixture. On the other hand, with the trend towards simplified product designs, more and more three-step injectors have eliminated the viewing window slot used for auxiliary fixation, resulting in a smooth outer shell surface without positioning references. This makes it difficult to maintain the activation state using conventional mechanical structures during testing, hindering accurate measurement of the static extension length of the needle.

[0004] Existing technologies have significant limitations in tooling for measuring the needle length of auto-injectors: some tooling is only suitable for two-step injectors with viewing window slots, and the excitation measurement is completed after the injector is fixed by the slot, which cannot be adapted to three-step products without slots; some large-scale automated testing equipment can achieve accurate measurement, but it is expensive, bulky, and its integrated design limits the testers' independent intervention and observation of each stage of the injection action, making it unsuitable for early-stage pilot-scale laboratories or low-cost quality control scenarios.

[0005] Therefore, there is an urgent need for a manual measuring fixture that is simple in structure, highly adaptable, and can simulate the complete three-step injection process to address the shortcomings of existing technologies. Utility Model Content

[0006] To solve the above-mentioned technical problems, this utility model provides the following technical solution:

[0007] A device for measuring the needle length of an auto-injector, the device comprising an upper structure and a lower structure, the upper structure and the lower structure being slidably connected by a sliding fit member;

[0008] The upper structure is a hollow frame structure. The top of the upper structure is provided with a limiting groove for accommodating the top of the automatic injector or the trigger button. The upper structure is provided with upper support arms on both sides, and the bottom of the two upper support arms is provided with positioning holes and connecting holes.

[0009] The lower structure includes a base, with lower support arms on both sides of the base. The lower support arms are slidably engaged with the upper support arms. The lower support arms have longitudinal hollow grooves. The sliding fitting is located in the hollow grooves. The upper support arms slide along the trajectory of the hollow grooves through the sliding fitting. The base has a receiving groove in the middle, and the receiving groove and the limiting groove are axially corresponding.

[0010] In one specific embodiment, the positioning hole is located on the inner side of the bottom end of the upper support arm, and the connecting hole is located on the outer side of the bottom end of the upper support arm.

[0011] In one specific embodiment, the sliding fit includes a nut and a screw. The screw passes through a connecting hole and a hollow groove. The nut is screwed onto both sides of the screw to fasten the upper support arm and the lower support arm. The screw moves up and down along the trajectory of the hollow groove to achieve a sliding connection between the upper structure and the lower structure.

[0012] In one specific embodiment, a limiting block is provided on the outer side of the lower support arm. The limiting block is used to limit the position of the sliding mating part to prevent the upper structure from slipping upward.

[0013] In one specific embodiment, a limiting platform is provided on the inner side of the lower support arm. The height of the limiting platform is lower than that of the limiting block, and the width of the limiting platform is the same as that of the upper structure, which is used to limit the range of the upper support arm's downward movement.

[0014] In one specific embodiment, the receiving groove is used to accommodate the needle of an auto-injector, and a viewing window is provided on one side of the base. The viewing window is a rectangular groove communicating with the receiving groove, and the viewing window is used to observe the extension length of the needle.

[0015] In one specific embodiment, the bottom of the base is provided with an instrument connection position for connecting with an external testing instrument, and the instrument connection position is provided with a threaded hole or a snap-fit ​​structure.

[0016] In one specific embodiment, the upper structure is an inverted U-shaped hollow rectangular frame structure.

[0017] In one specific embodiment, the upper and lower structures are made of polyoxymethylene, nylon, or aluminum alloy, and the hollow frame of the upper structure is provided with a buffer pad with a thickness of 0.5-2mm.

[0018] In one specific embodiment, the inner wall of the limiting groove is provided with anti-slip texture, the anti-slip texture is annular or grid-like, the depth of the limiting groove is 3-8mm, and the difference between the inner diameter of the limiting groove and the outer diameter of the top of the auto-injector or the trigger button is 0.5-2mm.

[0019] The beneficial effects of this utility model include:

[0020] 1. The device for measuring the needle length of an automatic injector provided by this utility model can realize the dynamic simulation of the entire firing process of the automatic injector through the sliding connection and cooperation between the upper and lower structures. By adjusting the distance between the upper and lower structures, it can be adapted to automatic injectors of various specifications. In addition, the setting of coaxial limiting groove and receiving groove can ensure the stability of the injector and needle, thereby improving the accuracy of detection and having good practicality.

[0021] 2. The device for measuring the needle length of an automatic injector provided by this utility model allows the screw to move up and down along the trajectory of the hollow groove when the nut is not tightened, enabling relative sliding between the upper and lower structures. The hollow groove acts as a slide rail, improving the guidance of the sliding process. When the nut is tightened, the upper and lower structures can be fixed and kept relatively stationary, which is beneficial for needle length detection. It has the advantages of being easy to operate and having a stable structure.

[0022] 3. The device for measuring the needle length of an auto-injector provided by this utility model has a simple overall structure, is easy to process, assemble and disassemble, and can intuitively reflect the extension position and length of the needle during the injection process. In addition, compared with expensive and complex fully automatic testing equipment, this device can reduce operating costs and is more suitable for step-by-step measurement and functional verification in laboratory conditions and pilot-scale stages, which is of great benefit to the research and development and verification stages of auto-injectors. Attached Figure Description

[0023] Figure 1 A schematic diagram of the overall structure of the device for measuring the needle length of an automatic injector provided by this utility model;

[0024] Figure 2 A schematic diagram of the upper structure of the device for measuring the needle length of an automatic injector provided by this utility model;

[0025] Figure 3 This is a schematic diagram of the lower structure of the device for measuring the needle length of an automatic injector provided by this utility model.

[0026] In the diagram, 1 is the upper structure; 2 is the lower structure; 3 is the screw; 4 is the nut; 5 is the limiting groove; 6 is the upper support arm; 7 is the positioning hole; 8 is the connecting hole; 9 is the base; 10 is the lower support arm; 11 is the hollow groove; 12 is the receiving groove; 13 is the limiting block; 14 is the limiting platform; 15 is the viewing window; and 16 is the instrument connection position. Detailed Implementation

[0027] The technical solution of this utility model will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0028] Example 1

[0029] like Figure 1-3 As shown in the figure, this embodiment illustrates a device for measuring the needle length of an auto-injector, comprising an upper structure 1 and a lower structure 2, which are slidably connected by a sliding fit; wherein,

[0030] The upper structure 1 is a hollow frame structure. In this embodiment, the upper structure 1 is an inverted U-shaped hollow rectangular frame structure with a limiting groove 5 at the top. The limiting groove 5 is used to accommodate the tip of the automatic injector or the activation button. The inner wall of the limiting groove 5 is provided with anti-slip texture, which is annular or grid-like. The depth of the limiting groove 5 is 3-8mm, and the difference between the inner diameter of the limiting groove 5 and the outer diameter of the tip of the automatic injector or the activation button is 0.5-2mm. The anti-slip texture increases the friction between the limiting groove 5 and the tip of the injector, preventing the injector from slipping during activation. The depth of 3-8mm ensures sufficient accommodating space, and the 0.5-2mm inner diameter difference allows for a certain tolerance range of injector adaptation while ensuring positioning accuracy, thus improving the versatility of this device.

[0031] The upper structure 1 has upper support arms 6 on both sides. Each upper support arm 6 has a positioning hole 7 and a connecting hole 8 at its bottom end. The positioning hole 7 is located inside the bottom end of the upper support arm 6, and the connecting hole 8 is located outside the bottom end of the upper support arm 6. The inner positioning hole 7 can accommodate the sliding mating parts, while the outer connecting hole 8 facilitates the installation and operation of the sliding mating parts, prevents them from shaking, and ensures overall stability.

[0032] The lower structure 2 includes a base 9, with lower support arms 10 on both sides of the base 9. The lower support arms 10 are slidably engaged with the upper support arms 6. The lower support arms 10 have longitudinal hollow grooves 11, and sliding fittings are located in the hollow grooves 11. The upper support arms 6 slide along the trajectory of the hollow grooves 11 through the sliding fittings. The base 9 has a receiving groove 12 in the middle, which is axially corresponding to the limiting groove 5. The coaxial arrangement ensures that the syringe can be stably fixed in the device, providing stable support for the syringe from both above and below, preventing the syringe from shaking and affecting the measurement accuracy.

[0033] The sliding mating component includes a nut 4 and a screw 3. The screw 3 passes through the connecting hole 8 and the hollow groove 11. The nut 4 is screwed onto both sides of the screw 3, securing the upper support arm 6 and the lower support arm 10. The screw 3 moves up and down along the trajectory of the hollow groove 11, achieving a sliding connection between the upper structure 1 and the lower structure 2. Through the cooperation of the nut 4 and the screw 3, the upper structure 1 can slide smoothly, simulating the firing action of an automatic injector, and the position can be locked during measurement to keep the needle extended. The structure is simple and easy to operate.

[0034] A limiting block 13 is provided on the outer side of the lower support arm 10. The limiting block 13 is used to limit the position of the sliding engagement component to prevent the upper structure 1 from slipping upward. A limiting platform 14 is provided on the inner side of the lower support arm 10. The height of the limiting platform 14 is lower than that of the limiting block 13, and the width of the limiting platform 14 is the same as that of the upper structure 1. It is used to limit the range of downward movement of the upper support arm 6. When the upper structure 1 slides upward to its maximum stroke, the sliding engagement nut 4 will contact the limiting block 13 to prevent the upper structure 1 from moving upward further and to prevent the upper structure 1 from slipping off the lower structure 2, thus improving the safety of the device. When the upper structure 1 slides downward to a certain position, the bottom end of the upper support arm 6 will contact the limiting platform 14 to limit the upper structure 1 from sliding downward further, avoiding structural damage caused by excessive pressing of the automatic injector, and also ensuring the consistency of the actuation action.

[0035] The receiving slot 12 is used to accommodate the needle of the auto-injector. A viewing window 15 is provided on one side of the base 9. The viewing window 15 is a rectangular groove that communicates with the receiving slot 12. The viewing window 15 is used to observe the extension length of the needle. The receiving slot 12 provides space for the needle, avoiding hard contact between the needle and the base 9. The viewing window 15, through its communication with the receiving slot 12, allows direct observation of the needle's extension status, facilitating the measurement of the needle's extension length using tools. The rectangular groove design also ensures a sufficient field of view.

[0036] The bottom of the base 9 is equipped with an instrument connection point 16, which is used to connect with external testing instruments. The instrument connection point 16 has a threaded hole or a snap-fit ​​structure. The upper structure 1 and the lower structure 2 are made of polyoxymethylene, nylon, or aluminum alloy. The hollow frame of the upper structure 1 has a buffer pad with a thickness of 0.5-2mm. Polyoxymethylene and nylon have wear resistance and self-lubricating properties, while aluminum alloy has high strength. All three materials are suitable for precision sliding structures. The buffer pad is preferably made of silicone or rubber to avoid hard contact between the automatic injector and the upper structure 1, preventing pen wear. At the same time, it can adapt to injectors of different outer diameters through slight deformation, improving the stability of the device.

[0037] The measurement process of the device for measuring the needle length of an auto-injector shown in this embodiment is as follows:

[0038] Assembly: Align the upper support arm 6 of the upper structure 1 with the lower support arm 10 of the lower structure 2, pass the screw 3 through the connecting hole 8 of the upper support arm 6 and the hollow groove 11 of the lower support arm 10, screw the nuts 4 into both sides, do not tighten them yet, leave some sliding allowance; check whether the sliding of the upper structure 1 is smooth, and whether the limit block 13 and the limit platform 14 can effectively limit the sliding range. After confirming that there are no errors, the assembly is completed.

[0039] Testing: Taking the measurement of the needle extension length of a three-step auto-injector as an example, remove the protective cap of the auto-injector and place its body into the hollow frame of the upper structure 1, so that the top activation button is embedded in the limiting groove 5, with the needle facing the receiving groove 12 of the base 9; hold the upper structure 1 and slowly slide it downward to simulate a pressing action, the upper support arm 6 moves down along the slide rail of the lower support arm 10 until the bottom end of the upper support arm 6 contacts the limiting platform 14, at which point the activation action is completed, and the needle extends out from the receiving groove 12; tighten the nut 4 of the sliding fit to lock the relative position of the upper structure 1 and the lower structure 2, keeping the needle in the extended state; observe the needle through the viewing window 15, and use a digital caliper or vernier caliper to measure the distance from the top of the receiving groove 12 to the needle tip, which is the needle extension length; after the measurement is completed, loosen the nut 4, slide the upper structure 1 upward to the limiting block 13, remove the auto-injector, and the measurement is complete.

[0040] In summary, the above embodiments are merely preferred embodiments of the present utility model and are not intended to limit the scope of protection of the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the scope of protection of the present utility model.

Claims

1. A device for measuring the needle length of an automatic injector, characterized in that, The device for measuring the needle length of an auto-injector includes an upper structure and a lower structure, which are slidably connected by a sliding fit. The upper structure is a hollow frame structure. The top of the upper structure is provided with a limiting groove for accommodating the top of the automatic injector or the trigger button. The upper structure is provided with upper support arms on both sides, and the bottom of the two upper support arms is provided with positioning holes and connecting holes. The lower structure includes a base, with lower support arms on both sides of the base. The lower support arms are slidably engaged with the upper support arms. The lower support arms have longitudinal hollow grooves. The sliding fitting is located in the hollow grooves. The upper support arms slide along the trajectory of the hollow grooves through the sliding fitting. The base has a receiving groove in the middle, and the receiving groove and the limiting groove are axially corresponding.

2. The device for measuring the needle length of an automatic injector according to claim 1, characterized in that, The positioning hole is located on the inner side of the bottom end of the upper support arm, and the connecting hole is located on the outer side of the bottom end of the upper support arm.

3. The device for measuring the needle length of an automatic injector according to claim 1, characterized in that, The sliding fit includes a nut and a screw. The screw passes through the connecting hole and the hollow groove. The nut is screwed on both sides of the screw to fasten the upper support arm and the lower support arm. The screw moves up and down along the trajectory of the hollow groove to achieve a sliding connection between the upper structure and the lower structure.

4. The device for measuring the needle length of an automatic injector according to claim 1, characterized in that, A limiting block is provided on the outer side of the lower support arm. The limiting block is used to limit the position of the sliding mating part to prevent the upper structure from slipping upward.

5. The device for measuring the needle length of an automatic injector according to claim 4, characterized in that, The lower support arm is provided with a limiting platform on its inner side. The height of the limiting platform is lower than that of the limiting block, and the width of the limiting platform is the same as that of the upper structure. It is used to limit the range of the upper support arm's downward movement.

6. The apparatus for measuring the needle length of an auto-injector according to claim 1, characterized in that, The receiving slot is used to accommodate the needle of the auto-injector. A viewing window is provided on one side of the base. The viewing window is a rectangular groove that communicates with the receiving slot. The viewing window is used to observe the extension length of the needle.

7. The device for measuring the needle length of an automatic injector according to claim 1, characterized in that, The bottom of the base is provided with an instrument connection position, which is used to connect with external testing instruments. The instrument connection position is provided with threaded holes or snap-fit ​​structures.

8. The apparatus for measuring the needle length of an automatic injector according to claim 1, characterized in that, The upper structure is an inverted U-shaped hollow rectangular frame structure.

9. The device for measuring the needle length of an automatic injector according to claim 1, characterized in that, The upper and lower structures are made of polyoxymethylene, nylon or aluminum alloy. The hollow frame of the upper structure is provided with a buffer pad with a thickness of 0.5-2mm.

10. The apparatus for measuring the needle length of an auto-injector according to claim 1, characterized in that, The inner wall of the limiting groove is provided with anti-slip texture, which is annular or grid-shaped. The depth of the limiting groove is 3-8mm, and the difference between the inner diameter of the limiting groove and the outer diameter of the top of the auto-injector or the trigger button is 0.5-2mm.

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