Needle tip protection apparatus
By designing a needle protection device consisting of an outer tube, a middle tube, an inner tube, and a button, and utilizing manual button triggering and spring drive, the problems of accidental triggering and complex structure in existing safety syringes are solved, achieving low-cost and high-reliability needle protection.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- GENRAY HANGZHOU LIFE TECH CO LTD
- Filing Date
- 2025-10-31
- Publication Date
- 2026-07-02
AI Technical Summary
Existing safety syringe needle protection devices have problems such as the risk of accidental triggering, complex structure, and high cost.
A needle protection device was designed, comprising an outer cylinder, a middle cylinder, an inner cylinder, a button, and a compression spring. It is manually triggered by the button and utilizes the cooperation of the limiting protrusion and the limiting hole, combined with the spring drive, to achieve reliable protection of the needle.
With its simple structure and low cost, it avoids the risk of accidental triggering and has no impact on use during injection, providing highly reliable needle protection.
Smart Images
Figure CN2025131794_02072026_PF_FP_ABST
Abstract
Description
A needle protection device Technical Field
[0001] This invention relates to the field of medical device technology, specifically to a needle protection device. Background Technology
[0002] Safety syringes are commonly used medical devices. To prevent accidental injury to users from the needle after use and to prevent the syringe from being reused, these syringes are usually equipped with a needle protection device that covers the needle after use to prevent accidental injury to users. Technical issues
[0003] In the existing technology, there are many types of safety syringes with needle protection devices, and the structure of their needle protection devices varies. Automatically triggered needle protection devices have the risk of accidental triggering, while manually triggered needle protection devices generally have technical defects such as complex structure and high cost. Technical solutions
[0004] The technical problem to be solved by the present invention is to provide a needle protection device with improved structure, which has the technical advantages of simple structure, convenient operation and high reliability.
[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a needle protection device, configured on the needle hub of a syringe, wherein the needle hub is provided with a needle tube, and the needle protection device includes at least:
[0006] The outer cylinder has its proximal end fixedly connected to the needle seat. A button mounting groove extending through the inner cavity is provided on the peripheral wall of the outer cylinder. A deformable baffle is provided on the distal end of the button mounting groove.
[0007] A button is hingedly mounted in a button mounting slot. The near end of the button has a limiting protrusion extending into the inner cavity of the outer cylinder, and the far end of the button has a pressing part.
[0008] The middle cylinder is located inside the inner cavity of the outer cylinder and can move axially relative to the outer cylinder. A first anti-detachment mechanism is provided between the proximal end of the middle cylinder and the distal end of the outer cylinder to prevent the middle cylinder from detaching from the outer cylinder. A first limiting hole is provided near the proximal end of the middle cylinder, penetrating into the inner cavity of the middle cylinder and accommodating the limiting protrusion.
[0009] The inner cylinder is sleeved on the needle tube. The inner cylinder is located inside the inner cavity of the middle cylinder and can move axially relative to the middle cylinder. A second anti-detachment mechanism is provided between the proximal end of the inner cylinder and the distal end of the middle cylinder to prevent the inner cylinder from detaching from the middle cylinder. A second limiting hole is provided near the proximal end of the inner cylinder to accommodate the entry of the limiting protrusion.
[0010] A compression spring is disposed between the needle seat and the inner cylinder;
[0011] The needle protection device has an initial state and a protective state. In the initial state, the limiting protrusion of the button passes through the first limiting hole and the second limiting hole in sequence, and the distal end of the button is tightly abutted against the baffle wall, keeping the middle cylinder and inner cylinder on the proximal side of the needle holder, and the needle tube is exposed outside the needle protection device. In the protective state, the button releases the restriction on the middle cylinder and inner cylinder, the compression spring drives the inner cylinder and moves the middle cylinder to the distal side of the needle holder, and the needle tube is kept inside the needle protection device.
[0012] In a preferred embodiment, the inner cavity of the outer cylinder is provided with a first inner boss near the distal end, and the proximal end of the middle cylinder is provided with a first outer boss for fitting with the first inner boss. The first inner boss and the first outer boss form the first anti-detachment mechanism.
[0013] In a preferred embodiment, the outer wall of the middle cylinder is provided with at least one axially extending first guide rib, and the first inner protrusion of the outer cylinder is provided with a first guide groove adapted to the first guide rib.
[0014] In a preferred embodiment, a second inner boss is provided near the distal end of the inner cavity of the middle cylinder, and a second outer boss is provided at the proximal end of the inner cylinder for fitting with the second inner boss. The second inner boss and the second outer boss form the second anti-detachment mechanism.
[0015] In a preferred embodiment, the outer wall of the inner cylinder is provided with at least one axially extending second guide rib, and the second outer protrusion of the middle cylinder is provided with a second guide groove adapted to the second guide rib.
[0016] In a preferred embodiment, the side of the baffle away from the button mounting slot is provided with a clearance groove.
[0017] In a preferred embodiment, hinge posts are provided on both sides of the button, and hinge holes adapted to the hinge posts are provided on both sides of the button mounting groove.
[0018] In a preferred embodiment, at least one hinge hole is provided with a notch to accommodate the hinge post entering the hinge hole radially.
[0019] In a preferred embodiment, a third inner boss is provided near the distal end of the inner cavity of the inner cylinder, and one end of the compression spring abuts against the third inner boss.
[0020] In a preferred embodiment, the middle cylinder is provided with a first elastic arm that extends obliquely from the proximal side to the distal side into the inner cavity near the distal end. In the protected state, the proximal end face of the inner cylinder crosses the free end of the first elastic arm, and the free end of the first elastic arm prevents the inner cylinder from moving towards the proximal side.
[0021] In a preferred embodiment, a locking part is provided on the distal end of the button. In the protected state, the locking part enters the inner cavity of the outer cylinder and is located at the bottom of the baffle wall, and the distal end face of the button prevents the middle cylinder from moving towards the proximal end.
[0022] In a preferred embodiment, the outer cylinder is provided with a second elastic arm that extends obliquely from the proximal side to the distal side into the inner cavity near the distal end. In the protected state, the proximal end face of the middle cylinder crosses the free end of the second elastic arm, and the free end of the second elastic arm prevents the inner cylinder from moving towards the proximal side.
[0023] In a preferred embodiment, the second elastic arm is located in a button mounting groove below the pressing portion of the button.
[0024] In a preferred embodiment, a circumferentially extending support arm is provided in the button mounting slot, and the second elastic arm extends from the support arm to the distal end.
[0025] In a preferred embodiment, a limiting boss is provided on at least one side wall of the button mounting groove, and a limiting groove for fitting the limiting boss is provided on the side wall of the button. Beneficial effects
[0026] The needle protection device and syringe of the present invention have the following advantages compared with the prior art:
[0027] (1) It includes five structural components: outer cylinder, middle cylinder, inner cylinder, button and compression spring. The number of structural components is small, the structure is simple, the assembly is convenient and the cost is low.
[0028] (2) The needle protection device consists of three sections in the length direction: inner cylinder, middle cylinder and outer cylinder when in the protective state. In the initial state, the middle cylinder and inner cylinder are both retracted into the outer cylinder. The axial dimension after retraction is small, and the coverage length of the needle tube is smaller, so as to minimize the impact of the needle protection device on the injection process.
[0029] (3) It can be manually triggered by a button, and the barrier needs to be deformed when triggered, which can effectively prevent the risk of accidental triggering and has better reliability.
[0030] (4) The button has multiple functions and has the technical advantage of ingenious design. Attached Figure Description
[0031] Figure 1 is a schematic diagram of the needle protection device of this embodiment as viewed from the proximal side in the initial state;
[0032] Figure 2 is a schematic diagram of the needle protection device of this embodiment as viewed from the distal end in the initial state;
[0033] Figure 3 is a cross-sectional view of the needle protection device in the initial state according to this embodiment;
[0034] Figure 4 is a magnified view of part A shown in Figure 3;
[0035] Figure 5 is a schematic diagram of the outer cylinder in this embodiment;
[0036] Figure 6 is a cross-sectional view of the outer cylinder in this embodiment;
[0037] Figure 7 is a schematic diagram of the structure of the middle cylinder in this embodiment;
[0038] Figure 8 is a cross-sectional view of the middle cylinder in this embodiment;
[0039] Figure 9 is a schematic diagram of the inner cylinder in this embodiment;
[0040] Figure 10 is a schematic cross-sectional view of the inner cylinder in this embodiment;
[0041] Figure 11 is a schematic diagram of the button structure in this embodiment;
[0042] Figure 12 is a schematic diagram of the needle protection device in the protective state according to this embodiment;
[0043] Figure 13 is a cross-sectional view of the needle protection device in the protected state according to this embodiment;
[0044] Figure 14 is a partially enlarged schematic diagram of part B shown in Figure 13;
[0045] Figure 15 shows a magnified view of part C as shown in Figure 13;
[0046] Figure 16 is a schematic diagram of another embodiment of the needle protection device of this embodiment;
[0047] Figure 17 is a schematic diagram of the outer cylinder in the needle protection device shown in Figure 16;
[0048] Figure 18 is a schematic diagram of the needle protection device according to another embodiment of this invention;
[0049] Figure 19 is a schematic diagram of the outer cylinder in the needle protection device shown in Figure 18;
[0050] Figure 20 is a cross-sectional view of the outer cylinder shown in Figure 19. The best embodiment of the present invention
[0051] Type the description paragraph of the best embodiment of the invention here. Embodiments of the present invention
[0052] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.
[0053] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.
[0054] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation", "connection" and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, an integral connection, or a detachable connection; they can refer to the internal connection of two components; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.
[0055] In the description of this invention, it should be noted that the operating side of the syringe is defined as the proximal end, and the needle side is defined as the distal end.
[0056] This embodiment provides a needle protection device for mounting on a syringe needle holder 60, on which a needle tube 70 is disposed. The needle protection device has an initial state and a protected state. In the initial state, as shown in Figures 1-3, the needle tube 70 is exposed outside the needle protection device, allowing for normal syringe operation. In the protected state, as shown in Figures 12 and 13, the needle tube 70 is retained within the needle protection device, thereby protecting the needle tube and preventing accidental needle puncture.
[0057] As a special feature of this embodiment, the needle protection device includes an inner cylinder 30, a middle cylinder 20, an outer cylinder 10, and a button 40 for triggering the needle protection device, which are sequentially sleeved from the inside to the outside. The structure of the outer cylinder 10 is shown in Figures 5 and 6. Its proximal end is provided with a connecting section 18 for fixing it to the needle holder 60. The connection method between the connecting section 18 and the needle holder 60 is not limited in this embodiment and can be conventional adhesive bonding or snap-fit.
[0058] In this embodiment, a first inner boss 13 is provided near the distal end of the inner cavity of the outer cylinder 10. Preferably, the first inner boss 13 is annular.
[0059] In this embodiment, a button mounting groove 11 extending into the inner cavity is provided on the peripheral wall of the outer cylinder. The button mounting groove 11 is used to mount the button 10. A deformable baffle 12 is provided on the distal end of the button mounting groove 11. Preferably, a clearance groove 15 is provided on the side of the baffle 12 away from the button mounting groove 11. The purpose of providing the clearance groove 15 is to provide deformation space for the baffle 12, so that the baffle arm 12 can deform under pressure.
[0060] In this embodiment, the button 40 is hingedly mounted in the button mounting slot 11, as shown in FIG11. Hinge posts 41 are provided on both sides of the button 40. Correspondingly, as shown in FIG5 and FIG6, hinge holes 16 are provided on both sides of the groove wall of the button mounting slot 11 to hinge with the hinge posts 41. Preferably, in this embodiment, at least one hinge hole 16 is provided with a notch 19 to accommodate the hinge post 41 entering the hinge hole 16 radially. The central angle of the notch 19 is typically less than 180°. The purpose of providing the notch 19 is to facilitate the installation of the button 40 into the button mounting slot 11.
[0061] In this embodiment, the near end of the button 40 is provided with a limiting protrusion 42 extending into the inner cavity of the outer cylinder, and the far end of the button 40 is provided with a pressing part 43.
[0062] In this embodiment, the middle cylinder 20 is located within the inner cavity of the outer cylinder 10 and can move axially relative to the outer cylinder 10. The structure of the middle cylinder 20 is shown in Figures 7 and 8. Its proximal end is provided with a first outer boss 22 for fitting with the first inner boss 13 to prevent the middle cylinder 20 from detaching from the outer cylinder 10. The first outer boss 22 and the first inner boss 13 form a first anti-detachment mechanism between the outer cylinder and the middle cylinder. Due to the presence of the first inner boss 13 and the first outer boss 22, the middle cylinder 20 will not detach from the outer cylinder 10 when it moves towards the distal end.
[0063] In this embodiment, to ensure that the middle cylinder 20 moves axially within the outer cylinder 10, an axially extending first guide rib 23 is provided on the outer wall of the middle cylinder 20. The number of first guide ribs 23 can be one, two, or more. Correspondingly, as shown in Figures 5 and 6, a first guide groove 14 adapted to the first guide rib 23 is provided on the first inner boss 13 of the outer cylinder 10.
[0064] In this embodiment, the middle cylinder 20 is provided with a first limiting hole 21 that penetrates into the inner cavity of the middle cylinder and accommodates the limiting protrusion 42 near the proximal end, and the inner cavity of the middle cylinder 20 is provided with a second inner protrusion 24 near the distal end.
[0065] In this embodiment, the inner cylinder 30 is sleeved on the needle tube 70. The inner cylinder 30 is located within the inner cavity of the middle cylinder 20 and can move axially relative to the middle cylinder 20. As shown in Figures 9 and 10, the proximal end of the inner cylinder 30 is provided with a second outer protrusion 32 for fitting with the second inner protrusion 24 to prevent the inner cylinder 30 from detaching from the middle cylinder 20. The second outer protrusion 32 and the second inner protrusion 24 form a second anti-detachment mechanism between the inner cylinder and the middle cylinder. Based on the presence of the second inner protrusion 24 and the second outer protrusion 32, when the inner cylinder 30 moves to the distal end, it will not detach from the middle cylinder 20.
[0066] In this embodiment, to ensure axial movement of the inner cylinder 30 within the middle cylinder 20, an axially extending second guide rib 33 is provided on the outer wall of the inner cylinder 30. The number of second guide ribs 33 can be one, two, or more. Correspondingly, as shown in Figures 7 and 8, a second guide groove 25 adapted to the second guide rib 33 is provided on the second inner boss 24 of the middle cylinder 20.
[0067] In this embodiment, the inner cylinder 30 is provided with a second limiting hole 33 near its proximal end to accommodate the entry of the limiting protrusion 42.
[0068] In this embodiment, the compression spring 50 is disposed between the needle seat 60 and the inner cylinder 30. Initially, it is in a compressed state, and its elastic potential energy is used to drive the inner cylinder 30 to move towards the distal end. Preferably, in this embodiment, a third inner boss 34 is provided near the distal end of the inner cavity of the inner cylinder 30, and one end of the compression spring 50 abuts against the third inner boss 34.
[0069] In this embodiment, as shown in Figures 3 and 4, in the initial state, the limiting protrusion 42 of the button 40 passes through the first limiting hole 21 and the second limiting hole 31 in sequence. Furthermore, the distal end of the button 40 is tightly abutted against the baffle 12. Without external force, the button 40, due to the tight abutment between its distal end and the baffle 12, cannot rotate around the hinge axis, thereby holding the middle cylinder 20 and the inner cylinder 30 on the proximal side of the needle holder 60. In this initial state, the needle tube 70 is exposed outside the needle protection device, which does not affect the normal use of the syringe.
[0070] After injection, press the pressing part 43 of button 40. Under the pressing action, button 40 rotates around the hinge axis. At the same time, the distal end face of button 40 acts on the baffle 12, causing the baffle 12 to deform, thereby allowing the button to rotate. During the rotation of the button, the limiting protrusion 42 of the button first disengages from the second limiting hole 31, releasing the elastic potential energy of the compression spring 50 and driving the inner cylinder 30 to move towards the distal end. As the button continues to rotate, the limiting protrusion 42 disengages from the first limiting hole 21, releasing the restriction on the middle cylinder 20. During the movement of the inner cylinder driven by the compression spring 50, the second outer protrusion 32 acts on the second inner protrusion 24, driving the middle cylinder 20 to move towards the distal end until the protective state shown in Figures 12 and 13 is reached. In the protective state, the needle tube remains inside the needle protection device.
[0071] In this embodiment, to limit the travel of the button when pressed, as shown in Figures 5, 6, and 11, a limiting boss 17 is provided on at least one side wall of the button mounting groove 11. Correspondingly, a limiting groove 45 is provided on the side wall of the button 40 for fitting with the limiting boss 17. When the limiting boss 17 engages with the limiting groove 45, the button will not rotate when pressed further.
[0072] In this embodiment, the needle protection device, in its protective state, also includes a backstop structure to prevent the inner cylinder 30 and the middle cylinder 20 from retracting proximally. Preferably, as shown in Figures 7, 8, 13, and 15, the middle cylinder 20 has a first elastic arm 26 extending obliquely from the proximal side to the distal side into the inner cavity near its distal end. When the needle protection device is triggered, as the inner cylinder 30 moves distally, its proximal end face passes over the free end of the first elastic arm 26. In the protective state, the free end of the first elastic arm 26 prevents the inner cylinder 30 from moving proximally, thus the elastic arm 26 forms a backstop structure for the inner cylinder.
[0073] In this embodiment, preferably as shown in Figures 11, 13, and 14, a locking part 44 is provided on the distal end of the button 40. During the process of pressing and rotating the button, the locking part 44 enters the inner cavity of the outer cylinder 10. In the protective state, the locking part 44 is located at the bottom of the baffle 12, preventing the button from rotating in the reverse direction. At the same time, the distal end face of the button 40 prevents the middle cylinder 20 from moving towards the proximal end. In this embodiment, the button 40 has multiple functions. First, in the initial state, it is used to restrict the position of the middle cylinder and the inner cylinder to the proximal end of the needle hub. Second, after injection, the button serves as the trigger mechanism of the needle protection device. Finally, in the protective state, the button is used as a stop structure for the middle cylinder.
[0074] In this embodiment, as a preferred alternative implementation of the middle tube anti-reverse structure, as shown in Figures 16 and 17, the outer tube 10 is provided with a second elastic arm 101 extending obliquely from the proximal side to the distal side into the inner cavity near the distal end. After the needle protection device is triggered, as the middle tube 20 moves towards the distal side, its proximal end face passes over the free end of the second elastic arm 101. In the protected state, the free end of the second elastic arm 101 prevents the middle tube 20 from moving towards the proximal side, and the second elastic arm 101 forms the anti-reverse structure of the middle tube.
[0075] In this embodiment, as a preferred embodiment, another implementation of the middle tube anti-reverse mechanism is shown in Figures 18-20, where the second elastic arm 101 is located within the button mounting groove 11 below the pressing portion of the button. Specifically, a circumferentially extending support arm 102 is provided within the button mounting groove 11, and the second elastic arm 101 extends distally from the support arm 102. In this embodiment, after the needle protection device is triggered, as the middle tube 20 moves distally, its proximal end face passes over the free end of the second elastic arm 101. In the protected state, the free end of the second elastic arm 101 prevents the middle tube 20 from moving proximally, and the second elastic arm 101 forms the anti-reverse structure of the middle tube.
[0076] In summary, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention. Industrial applicability
[0077] Type the industrial utility description paragraph here. Sequence List Free Content
[0078] Type the free content description paragraph for the sequence list here.
Claims
1. A needle protection device for mounting on a needle holder (60) of a syringe, wherein a needle tube (70) is disposed on the needle holder, characterized in that, The needle protection device includes at least: The outer cylinder (10) is fixedly connected to the needle seat at its proximal end. A button mounting groove (11) extending through the inner cavity is provided on the peripheral wall of the outer cylinder. A deformable baffle (12) is provided on the distal side of the button mounting groove (11). Button (40), the button is hinged in the button mounting groove (11), the near end of the button is provided with a limiting protrusion (42) extending into the inner cavity of the outer cylinder, and the far end of the button is provided with a pressing part (43). The middle cylinder (20) is located inside the inner cavity of the outer cylinder and can move axially relative to the outer cylinder. A first anti-detachment mechanism is provided between the proximal end of the middle cylinder and the distal end of the outer cylinder to prevent the middle cylinder from detaching from the outer cylinder. A first limiting hole (21) is provided near the proximal end of the middle cylinder, penetrating into the inner cavity of the middle cylinder and accommodating the passage of the limiting protrusion. Inner cylinder (30), the inner cylinder is sleeved on the needle tube, the inner cylinder is located in the inner cavity of the middle cylinder and can move axially relative to the middle cylinder, a second anti-detachment mechanism is provided between the proximal end of the inner cylinder and the distal end of the middle cylinder to prevent the inner cylinder from detaching from the middle cylinder, and a second limiting hole is provided near the proximal end of the inner cylinder to accommodate the entry of the limiting protrusion. Compression spring (50), the compression spring being disposed between the needle seat and the inner cylinder; The needle protection device has an initial state and a protective state. In the initial state, the limiting protrusion of the button passes through the first limiting hole and the second limiting hole in sequence, and the distal end of the button is tightly abutted against the baffle, keeping the middle cylinder and inner cylinder on the proximal side of the needle holder, and the needle tube is exposed outside the needle protection device. In the protective state, the button releases the restriction on the middle cylinder and inner cylinder, the compression spring drives the inner cylinder and moves the middle cylinder to the distal side of the needle holder, and the needle tube is kept inside the needle protection device.
2. The needle protection device according to claim 1, characterized in that, The inner cavity of the outer cylinder is provided with a first inner boss (13) near the far end, and the middle cylinder is provided with a first outer boss (22) for matching the first inner boss. The first inner boss (13) and the first outer boss (22) form the first anti-detachment mechanism.
3. The needle protection device according to claim 2, characterized in that, The outer wall of the middle cylinder is provided with at least one axially extending first guide rib (23), and the first inner boss of the outer cylinder is provided with a first guide groove (14) adapted to the first guide rib.
4. The needle protection device according to claim 1, characterized in that, The inner cavity of the middle cylinder is provided with a second inner boss (24) near the far end, and the near end of the inner cylinder is provided with a second outer boss (32) for matching the second inner boss. The second inner boss (24) and the second outer boss (32) form the second anti-detachment mechanism.
5. The needle protection device according to claim 4, characterized in that, The outer wall of the inner cylinder is provided with at least one axially extending second guide rib (33), and the second outer protrusion of the middle cylinder is provided with a second guide groove (25) adapted to the second guide rib.
6. The needle protection device according to claim 1, characterized in that, A clearance groove (15) is provided on the side of the baffle away from the button mounting groove.
7. The needle protection device according to claim 1, characterized in that, The button is provided with hinge posts (41) on both sides, and the side walls of the button mounting groove are provided with hinge holes (16) that are adapted to the hinge posts.
8. The needle protection device according to claim 7, characterized in that, At least one hinge hole is provided with a notch (19) to accommodate the hinge post entering the hinge hole radially.
9. The needle protection device according to claim 1, characterized in that, A third inner boss (34) is provided near the far end of the inner cavity of the inner cylinder, and one end of the compression spring abuts against the third inner boss.
10. The needle protection device according to claim 1, characterized in that, The middle cylinder is provided with a first elastic arm (26) that extends obliquely from the proximal side to the distal side into the inner cavity near the distal end. In the protected state, the proximal end face of the inner cylinder crosses the free end of the first elastic arm, and the free end of the first elastic arm prevents the inner cylinder from moving towards the proximal side.
11. The needle protection device according to claim 1, characterized in that, The button has a locking part (44) on its distal end. In the protected state, the locking part enters the inner cavity of the outer cylinder and is located at the bottom of the baffle. The distal end face of the button prevents the middle cylinder from moving to the proximal end.
12. The needle protection device according to claim 1, characterized in that, The outer cylinder is provided with a second elastic arm (101) that extends obliquely from the proximal side to the distal side into the inner cavity near the distal end. In the protected state, the proximal end face of the middle cylinder crosses the free end of the second elastic arm, and the free end of the second elastic arm prevents the inner cylinder from moving towards the proximal side.
13. The needle protection device according to claim 12, characterized in that, The second elastic arm (101) is located in the button mounting groove (11) below the pressing part (43) of the button.
14. The needle protection device according to claim 13, characterized in that, The button mounting slot is provided with a circumferentially extending support arm (102), and the second elastic arm (101) extends from the support arm (102) to the distal end.
15. The needle protection device according to claim 1, characterized in that, A limiting boss (17) is provided on at least one side wall of the button mounting groove, and a limiting groove (45) is provided on the side wall of the button for fitting the limiting boss.