Blood taking needle

Abstract

The utility model relates to a blood taking needle which comprises an outer sleeve provided with a first end and a second end, the second end is provided with a needle outlet, and the inner wall of the outer sleeve is provided with a key guide face inclined relative to the axial direction; the core is suitable for being assembled in the outer sleeve, a needle head is arranged at the end, close to the needle outlet, of the needle core, and a stop part is arranged on the outer wall of the needle core; the key is suitable for being assembled at the first end of the outer sleeve in a pressing mode in the direction facing the needle outlet and comprises a key cap and an extending part, the extending part is located on the side, facing the needle outlet, of the key cap, the extending part is provided with a driving face and a stopping table, and the stopping table is suitable for abutting against the stopping part; and the driving surface is suitable for moving along the key guide surface and driving the stop table to move in the radial direction when the key moves towards the needle outlet, so that the stop table is separated from the radial position of the stop part to allow the needle core to move towards the needle outlet. According to the blood taking needle, delay can be avoided.

Description

Technical Field

[0001] Embodiments of this disclosure relate to the field of medical devices, and more particularly to a blood collection needle. Background Technology

[0002] The existing top-triggered lancet uses a button-driven needle core rotation and firing mechanism. After pressing the top button to trigger firing, the two wings of the needle core enter the firing slot and move towards the needle outlet, thus completing the firing of the lancet. Due to gaps between the components of the lancet, the two wings of the needle core cannot immediately enter the firing slot after pressing the top button to trigger firing, resulting in a firing delay. Utility Model Content

[0003] This disclosure is made to alleviate or resolve at least one aspect or point of the above-mentioned problems.

[0004] This disclosure provides a blood collection needle, comprising: an outer sheath having a first end and a second end, the second end having a needle outlet, and the inner wall of the outer sheath having a button guide surface inclined relative to the axial direction; a needle core adapted to be assembled inside the outer sheath, the end of the needle core near the needle outlet having a needle tip, and the outer wall of the needle core having a stop portion; a button adapted to be pressed onto the first end of the outer sheath toward the needle outlet, comprising a keycap and an extension portion, the extension portion being located on the side of the keycap toward the needle outlet, the extension portion having a drive surface and a stop platform, the stop platform being adapted to abut against the stop portion; the drive surface being adapted to move along the button guide surface and drive the stop platform to move radially when the button moves toward the needle outlet, such that the stop platform disengages from the radial position blocking the stop portion to allow the needle core to move toward the needle outlet.

[0005] In an optional embodiment, the inner wall of the outer sleeve is further provided with an axially extending needle core guide structure, and the outer wall of the needle core is further provided with a guide portion, which is adapted to slide within the needle core guide structure.

[0006] In an optional embodiment, the extension includes at least one extension arm, the end of which is bent to form the stop platform, and the end of the extension arm has an inner chamfer, the surface of which forms the drive surface.

[0007] In an optional embodiment, the button guide surface extends radially outward from the first end to the second end, such that when the button moves toward the needle outlet, the stop platform moves radially outward.

[0008] In an optional embodiment, the inner wall of the outer sleeve is further provided with a control step, which is closer to the needle outlet than the stop platform; the needle core is further provided with a control part, and the control step is adapted to prevent the control part from moving toward the needle outlet.

[0009] In an optional embodiment, the control part and the stop part are spaced a certain distance apart in the axial direction, and the control part is closer to the needle outlet than the stop part.

[0010] In an optional embodiment, the control unit and the stop unit have the same structure.

[0011] In an optional embodiment, the protrusion direction of the guide portion and the protrusion direction of the stop portion differ by 90° in the circumferential direction.

[0012] In an optional embodiment, the inner wall of the outer jacket is provided with pairs of inwardly protruding needle core guide protrusions, and the needle core guide structure is formed between each pair of needle core guide protrusions.

[0013] In an optional embodiment, the needle core guide protrusion is provided with a button guide protrusion, the protrusion direction of the button guide protrusion is perpendicular to the protrusion direction of the needle core guide protrusion, and the surface of the button guide protrusion forms the button guide surface.

[0014] In an optional embodiment, the extension includes a plurality of extension arms that are evenly arranged circumferentially, and each extension arm is provided with a corresponding drive surface and a stop platform.

[0015] In an optional embodiment, both the stop platform and the drive surface are located at the end of the extension arm, with the drive surface located on both sides of the stop platform in the circumferential direction.

[0016] In an optional embodiment, a launch spring is further included, disposed between the button and the pin.

[0017] In an optional embodiment, a return spring is further included, disposed between the needle core and the second end of the outer sleeve.

[0018] In an optional embodiment, it further includes: a needle cap for covering the needle tip, the needle cap comprising a first portion adapted to be fitted inside the outer sheath and a second portion located outside the outer sheath.

[0019] In an optional embodiment, the outer wall of the needle cap is provided with an outwardly protruding boss, which is adapted to abut against the inner end face of the second end of the outer sleeve; when the boss abuts against the inner end face of the second end of the outer sleeve, the end of the first part abuts against the needle core, such that the stop portion and the stop platform are spaced a certain distance apart.

[0020] In an optional embodiment, a stop rib is provided at the first end of the outer sleeve, the stop rib being adapted to prevent the keycap from moving toward the needle outlet.

[0021] In an optional implementation, the cross-sectional area of ​​the outer jacket gradually decreases from the first end to the second end. Attached Figure Description

[0022] Figure 1 This is a perspective view of a jacket according to an exemplary embodiment of the present disclosure;

[0023] Figure 2 for Figure 1 A cross-sectional diagram of the inner and outer layers;

[0024] Figure 3 This is a perspective view of a needle core according to an exemplary embodiment of the present disclosure;

[0025] Figure 4 This is a perspective view of a button according to an exemplary embodiment of the present disclosure;

[0026] Figure 5 This is a schematic diagram of a blood collection needle in an assembled state according to an exemplary embodiment of the present disclosure, showing a cross-section of the blood collection needle after it has been cut along the axial direction;

[0027] Figure 6 for Figure 5 A three-dimensional diagram of the blood collection needle, in which the return spring 42 is omitted for easier observation;

[0028] Figure 7 for Figure 6 A magnified view of a portion of the blood collection needle;

[0029] Figure 8 This is a schematic diagram of a blood collection needle in a firing state according to an exemplary embodiment of the present disclosure;

[0030] Figure 9 This is a schematic diagram of a blood collection needle during the firing process according to an exemplary embodiment of the present disclosure;

[0031] Figure 10 This is a schematic diagram of a blood collection needle after firing, according to an exemplary embodiment of the present disclosure.

[0032] In the diagram: 1. Outer jacket; 11. Needle core guide protrusion; 12. Needle core guide structure; 13. Button guide protrusion; 14. Button guide surface; 15. Control step; 16. Needle outlet; 19. Recess; 2. Needle core; 21. Guide part; 22. Stop part; 23. Control part; 24. Needle tip; 25. Needle cap; 26. Boss; 3. Button; 31. Keycap; 32. Extension arm; 33. Stop platform; 34. Drive surface; 35. Bottom protrusion; 41. Launch spring; 42. Return spring. Detailed Implementation

[0033] The technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art based on this application are within the scope of protection of this disclosure.

[0034] The blood collection needle in this embodiment eliminates the needle core side wing-emission groove structure. It utilizes the stop portion on the outer wall of the needle core to cooperate with the stop platform of the button extension, limiting the axial position of the needle core before emission. Furthermore, the button guide surface on the inner wall of the outer sleeve cooperates with the driving surface of the button extension, converting the axial movement of the button into radial movement of the stop platform. This allows the stop platform to disengage from the radial position blocking the stop portion, enabling the needle core to move axially and achieve emission. Before emission, the stop portion directly abuts against the stop platform of the button. After pressing the top button to trigger emission, the needle core can immediately move axially towards the needle outlet, eliminating the gap that occurs when the needle core side wing rotates into the emission groove in the prior art, thus solving the problem of delayed emission.

[0035] In the embodiments of this disclosure, the outer jacket can be considered as a stretched body, with the stretching direction being axial. The cross-section perpendicular to the axial direction is the cross section, and the circumferential direction of the cross section is circumferential. The direction of the line connecting the center of the cross section and the outer edge of the cross section is radial. The stretching can be constant-diameter stretching (e.g., stretching a circle into a cylinder) or variable-diameter stretching (e.g., stretching a circle into a cone, frustum, or variable-diameter cylinder). The cross section of the outer jacket can be circular, or it can be elliptical, rectangular, rounded rectangle, etc., etc. For example, in... Figure 5 In the diagram, the vertical direction is the stretching direction, which is the axial direction.

[0036] In embodiments of this disclosure, the interior of the outer jacket forms a cavity. In embodiments of this disclosure, "inner" refers to the direction toward the center of the cavity, and "outer" refers to the direction away from the center of the cavity.

[0037] The technical solution of this disclosure will be described in more detail below with reference to the accompanying drawings.

[0038] Figure 1This is a perspective view of a jacket according to an exemplary embodiment of the present disclosure. Figure 2 for Figure 1 A cross-sectional diagram of the inner and outer layers.

[0039] like Figure 1 As shown, the outer casing 1 is cylindrical in shape. In an optional embodiment, as... Figure 1 As shown, the outer jacket 1 may include a thinner portion (e.g. Figure 1 The lower part and the thicker part (e.g.) Figure 1 The upper part of the middle section). The bottom of the aforementioned finer part (i.e., the lower end of the outer jacket 1) may be provided with a needle outlet 16 (see the upper part of the outer jacket 1). Figure 2 The thicker part mentioned above (i.e., the upper end of the outer casing 1) can be used to assemble the button 3 (see...). Figures 5-6 , Figures 8-10 ).

[0040] In an optional embodiment, the cross-section of the outer casing 1 can be elliptical. The spaces corresponding to the two ends of the major axis of the ellipse can be used to accommodate a pair of extension arms 32 of the button 3 (see...). Figure 4 This helps to reduce the size of the blood collection needle.

[0041] In optional embodiments, such as Figure 1 As shown, the cross-sectional area of ​​outer jacket 1 gradually decreases from its upper end to its lower end. Here, cross-sectional area refers to the area of ​​the planar shape defined by the outer contour of the cross-section. It should be noted that while the cross-sectional area gradually decreases, portions with equal cross-sectional areas are permissible; for example, the cross-sectional areas of the thicker portions mentioned above are essentially the same.

[0042] like Figure 2 As shown, the inner wall of the outer casing 1 is provided with a button guide surface 14 that extends obliquely relative to the axial direction.

[0043] In optional embodiments, such as Figure 2 As shown, the inner wall of the outer jacket 1 is also provided with an axially extending needle core guide structure 12. Figure 2 In the middle, the needle core guide structure 12 is a groove, but it can also be in other forms.

[0044] In optional embodiments, such as Figure 2 As shown, from the upper end to the lower end of the outer casing 1, the button guide surface 14 extends outward at an angle.

[0045] In optional embodiments, such as Figure 2 As shown, the inner wall of the outer jacket 1 is provided with pairs of inwardly protruding needle core guide protrusions 11. Figure 2The diagram shows a pair of needle core guide protrusions 11, and another pair of needle core guide protrusions 11 in the cut-out portion. The needle core guide protrusions 11 protrude radially inward and extend axially for a certain length. The needle core guide structure 12 described above is formed between the pair of needle core guide protrusions 11. The axial extension length of the needle core guide protrusions 11 defines the axial length of the needle core guide structure 12.

[0046] In optional embodiments, such as Figure 2 As shown, a button guide protrusion 13 is provided on the needle core guide protrusion 11, and the protrusion direction of the button guide protrusion 13 is perpendicular to the protrusion direction of its corresponding needle core guide protrusion 11. Figure 2 As shown, the button guide protrusion 13 forms the aforementioned button guide surface 14 on its end face in the protrusion direction.

[0047] In optional embodiments, such as Figure 2 As shown, the inner wall of the outer casing 1 is also provided with a control step 15. See below. Figure 9 On the right half, the control step 15 is closer to the needle outlet 16 than the stop platform 33. The control step 15 is adapted to prevent the control unit 23 from moving toward the needle outlet 16.

[0048] exist Figure 2 In the illustrated embodiment, there are two needle guide structures 12. In other embodiments, there may be one or more needle guide structures 12. When there are multiple needle guide structures 12, they can be evenly arranged circumferentially.

[0049] Figure 3 This is a perspective view of a needle core according to an exemplary embodiment of the present disclosure.

[0050] Needle core 2 is adapted to be fitted inside outer casing 1 (see Figures 5-10 Its lower end is near the needle outlet 16 (see Figures 8-10 The lower end of the needle core 2 is provided with a needle tip 24 (see...). Figure 8 and Figure 9 ).like Figure 3 As shown, the outer wall of the needle core 2 is provided with a stop part 22.

[0051] In optional embodiments, such as Figure 3 As shown, the outer wall of the needle core 2 is also provided with a guide portion 21. The guide portion 21 is adapted to be in the needle core guiding structure 12 (see... Figure 2 Slide inside.

[0052] exist Figure 3In the middle, the stop portion 22 is closer to the upper end relative to the guide portion 21. The axial positions of the stop portion 22 and the guide portion 21 can be interchanged; for example, although not shown, the stop portion 22 can be closer to the lower end relative to the guide portion 21.

[0053] In an optional embodiment, the protrusion directions of the stop portion 22 and the guide portion 21 differ by 90° in the circumferential direction. Alternatively, they may differ by other angles.

[0054] In optional embodiments, such as Figure 3 As shown, a control section 23 is also provided on the outer wall of the needle core 2. The control section 23 and the stop section 22 are spaced a certain distance apart axially, and the control section 23 is lower than the stop section 22. See the following... Figure 9 The right half of the needle core 2 moves a certain distance towards the needle outlet 16, and the control part 23 is blocked by the control step 15. At this time, the length of the needle tip 24 exposed from the outer sheath 1 is the puncture length of the blood collection needle.

[0055] In an optional embodiment, although not shown, the control unit 23 may be omitted, and the control step 15 may directly block the stop part 22 to control the puncture length of the blood collection needle. Alternatively, the control unit 23 and the stop part 22 may be the same structure.

[0056] In optional embodiments, such as Figure 3 As shown, a needle cap 25 is provided at the lower end of the needle core 2. The needle cap 25 is used to cover and protect the needle tip 24 (see...). Figure 8 and Figure 9 The needle cap 25 includes a first part adapted to be fitted inside the outer cover 1 and a second part located outside the outer cover 1 (see...). Figure 5 and Figure 6 ).

[0057] In optional embodiments, such as Figure 3 As shown, the outer wall of the needle cap 25 is provided with an outwardly protruding boss 26. The boss 26 is adapted to abut against the inner end face of the lower end of the outer sleeve 1 (see...). Figure 6 (Left half)

[0058] In an optional embodiment, the needle outlet 16 can be elliptical. When the boss 26 is aligned with the minor axis of the elliptical needle outlet, the boss 26 abuts against the inner end face of the lower end of the outer sleeve 1. When the boss 26 is aligned with the major axis of the elliptical needle outlet, the boss 26 can pass through the needle outlet 16.

[0059] Figure 4 This is a perspective view of a button according to an exemplary embodiment of the present disclosure.

[0060] like Figure 4 As shown, button 3 is adapted to be mounted on the upper end of outer casing 1 (see Figure 1). Figures 5-6 , Figures 8-10 It includes keycap 31 and an extension. Figure 4 In this embodiment, the extension is specifically an extension arm 32. In other embodiments, although not shown, the extension may be in other forms besides an arm, such as a sheet, a tube, etc. The extension arm 32 is located on the side of the keycap 31 facing the needle outlet 16 (see [link to keycap description]). Figures 5-6 , Figures 8-10 (i.e., the lower side). The extension arm 32 is provided with a drive surface 34 and a stop platform 33. See below. Figure 8 Before the needle core is fired, the stop platform 33 abuts against the stop part 22.

[0061] In optional embodiments, such as Figure 4 As shown, the end of the extension arm 32 is bent to form a stop platform 33. Simultaneously, the end of the extension arm 32 is provided with two inner chamfers, which are aligned with the button guide surface 14 (see...). Figure 2 The corresponding surface forms the driving surface 34.

[0062] In optional embodiments, such as Figure 4 As shown, both the stop platform 33 and the drive surface 34 are located at the end of the extension arm 32. Figure 4 In the center, the stop platform 33 is a horizontal plane, and the driving surface 34 is a vertical plane. The driving surface 34 is located on both sides of the stop platform 33 in the circumferential direction.

[0063] In an optional embodiment, the extension arm 32 is a flexible arm.

[0064] In an optional embodiment, the number of extension arms 32 can be multiple (exemplary, Figure 4 (There are two in the middle), the above-mentioned multiple extension arms 32 can be evenly arranged along the circumference of the outer sleeve 1. Each extension arm 32 is provided with a corresponding drive surface 34 and a stop platform 33.

[0065] Figure 5 This is a schematic diagram of a blood collection needle in an assembled state according to an exemplary embodiment of the present disclosure. Figure 6 for Figure 5 A three-dimensional diagram of the blood collection needle, in which the return spring 42 is omitted for easier observation. Figure 7 for Figure 6 A magnified schematic diagram of a blood collection needle.

[0066] In optional embodiments, such as Figure 5 As shown, a launching spring 41 is provided between the button 3 and the needle core 2, and a return spring 42 is provided between the needle core 2 and the inner end face of the lower end of the outer sleeve 1.

[0067] In optional embodiments, such as Figure 4 As shown, the top of the keycap 31 is for the operator to press, and the bottom of the keycap 31 has a bottom protrusion 35. Figure 5 As shown, the two ends of the launching spring 41 are respectively sleeved on the upper end of the needle core 2 and the bottom protrusion 35 of the button 3.

[0068] like Figure 6 As shown, in the assembled state, the needle cap 25 is connected to the needle core 2, the protrusion 26 of the needle cap 25 abuts against the inner end face of the lower end of the outer sleeve 1, and the upper end of the needle cap 25 pushes the needle core 2 upward, so that the stop part 22 and the stop platform 33 are spaced a certain distance apart (see...). Figure 6 right half and Figure 7 At this point, the launching spring 41 has a large compression. This state can be applied to the packaging and transportation of blood collection needles.

[0069] Figure 8 This is a schematic diagram of a blood collection needle in a firing-ready state according to an exemplary embodiment of the present disclosure. Figure 5-7 Based on the shown state, the operator can rotate the needle cap 25 so that the protrusion 26 of the needle cap 25 is aligned with the long axis of the needle outlet 16, thereby removing the needle cap 25 from the needle core 2 and taking it out of the outer sleeve 1, thus turning the blood collection needle into... Figure 8 The state shown is ready to launch.

[0070] like Figure 8 As shown, without the support of the needle cap 25, the needle core 2 moves axially downward a certain distance under the action of the launching spring 41 until the stop part 22 of the needle core 2 abuts against the stop platform 33 of the button 3. Since the stop platform 33 overlaps with the stop part 22 in the radial direction, it can block the axial movement of the stop part 22, so that the needle core 2 cannot continue to move downward.

[0071] Before and after the needle core 2 is fired, the guide part 21 of the needle core 2 is always located inside the needle core guide structure 12 on the inner wall of the outer sleeve 1, so the circumferential rotation of the needle core 2 is restricted and it can only move axially.

[0072] Figure 9 This is a schematic diagram of a blood collection needle during the firing process according to an exemplary embodiment of this disclosure. Figure 8 Based on the indicated state, the operator presses button 3, causing button 3 to move downwards, achieving... Figure 9 The state shown.

[0073] See Figure 8 (For details of the contact between the extension arm 32 and the button guide surface 14, please refer to...) Figure 7 As button 3 moves downward, the driving surface 34 of the extension arm 32 moves downward relative to the button guide surface 14. Since the button guide surface 14 extends radially outward from top to bottom, the driving surface 34 and the extension arm 32 move radially outward simultaneously as they move downward. The stop platform 33 moves radially outward accordingly. After the stop platform 33 has moved a certain distance, it no longer obstructs the axial movement of the stop part 22, and the needle core 2 continues to move downward, reaching... Figure 9 The state shown enables the firing of needle core 2.

[0074] See Figure 9 Due to the presence of the control step 15, the needle core 2 does not move downward continuously after being fired, but stops moving downward after contacting the control step 15. At this time, the needle core 2 reaches the maximum firing distance, and the length of the needle tip 24 exposed from the outer sheath 1 is the puncture length of the blood collection needle.

[0075] Figure 10 This is a schematic diagram of a blood collection needle after firing, according to an exemplary embodiment of the present disclosure.

[0076] See Figure 9 After the needle 24 reaches the puncture length, the return spring 42 (see...) Figure 10 This causes the needle 24 to move upwards, eventually retracting into the outer casing 1 and remaining stationary inside the outer casing 1, achieving... Figure 10 The state shown is to prevent the needle 24 from being exposed and causing danger.

[0077] In the above embodiments, the guide portion is a protrusion and the needle core guide structure is a groove. Alternatively, the two forms can be interchanged, with the guide portion having a groove and the needle core guide structure being a protrusion.

[0078] In the above embodiments, the stop portion is protruding. In other embodiments, the stop portion can also be a groove, and the stop platform of the extension portion can extend into the groove to prevent the needle core from moving axially.

[0079] In the embodiments of this disclosure, the relative positions of the guide portion and the stop portion in the axial direction can be set as needed. The guide portion may be on top, the stop portion may be on top, or the two may have overlapping portions in the axial direction.

[0080] In the embodiments of this disclosure, when there are multiple stop parts and multiple stop platforms, each stop part cooperates with a corresponding stop platform.

[0081] It should be noted that the above technical solutions can be combined arbitrarily where logically possible, and all are within the scope of protection of this disclosure. In this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0082] The various embodiments in this specification are described in a related manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0083] Although embodiments of the present disclosure have been shown and described, it will be understood by those skilled in the art that variations and combinations of elements may be made to these embodiments without departing from the principles and spirit of the present disclosure, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A lancet, comprising: The application relates to a needle assembly, comprising: a sleeve having a first end and a second end, the second end being provided with a needle outlet, an inner wall of the sleeve being provided with a key guide surface inclined relative to an axial direction; a needle core adapted to be assembled inside the sleeve, an end of the needle core close to the needle outlet being provided with a needle head, an outer wall of the needle core being provided with a stop portion; a key adapted to be assembled at the first end of the sleeve in a pressing manner towards the needle outlet, the key comprising a key cap and an extension part, the extension part being located on a side of the key cap towards the needle outlet, the extension part being provided with a driving surface and a stop platform, the stop platform being adapted to abut against the stop portion; the driving surface being adapted to move along the key guide surface and drive the stop platform to move in a radial direction when the key moves towards the needle outlet, so that the stop platform is separated from a radial position for blocking the stop portion to allow the needle core to move towards the needle outlet.

2. The lancet of claim 1 wherein, the inner wall of the sleeve is further provided with a needle core guide structure extending in an axial direction, and the outer wall of the needle core is further provided with a guide portion adapted to slide in the needle core guide structure.

3. The lancet of claim 1 wherein, the extension part comprises at least one extension arm, an end of the extension arm is bent to form the stop platform, and the end of the extension arm has an inner chamfer, and a surface of the inner chamfer forms the driving surface.

4. The lancet of claim 1 wherein, from the first end to the second end, the key guide surface extends outward in a radial direction, so that the stop platform moves outward in a radial direction when the key moves towards the needle outlet.

5. The lancet of claim 1 wherein, the inner wall of the sleeve is further provided with a control step, and the control step is closer to the needle outlet relative to the stop platform; the needle core is further provided with a control portion, and the control step is adapted to block the control portion from moving towards the needle outlet.

6. The lancet of claim 5 wherein, the control portion and the stop portion are spaced apart in an axial direction, and the control portion is closer to the needle outlet relative to the stop portion.

7. The lancet of claim 5 wherein, the control portion and the stop portion are the same structure.

8. The lancet of claim 2 wherein, a convex direction of the guide portion and a convex direction of the stop portion are different by 90 degrees in a circumferential direction.

9. The lancet of claim 2 wherein, the inner wall of the sleeve is provided with a pair of needle core guide protrusions protruding inward, and a needle core guide structure is formed between each pair of needle core guide protrusions.

10. The lancet of claim 9 wherein, the needle core guide protrusions are provided with key guide protrusions, a convex direction of the key guide protrusions is perpendicular to a convex direction of the needle core guide protrusions, and a surface of the key guide protrusions forms the key guide surface.

11. The lancet of claim 1 wherein, the extension part comprises a plurality of extension arms, the plurality of extension arms are uniformly arranged in a circumferential direction, and each of the extension arms is provided with a corresponding driving surface and stop platform.

12. The lancet of claim 11 wherein, the stop platform and the driving surface are located at an end of the extension arm, and the driving surface is located on both sides of the stop platform in a circumferential direction.

13. The lancet of claim 1 wherein, further comprising: a launching spring arranged between the key and the needle core.

14. The lancet of claim 1 wherein, further comprising: a reset spring arranged between the needle core and the second end of the sleeve.

15. The lancet of claim 1 wherein, further comprising: a needle cap used for covering the needle head, the needle cap comprising a first part adapted to be assembled inside the sleeve and a second part located outside the sleeve.

16. The lancet of claim 15 wherein, an outer wall of the needle cap is provided with a convex boss protruding outward, and the convex boss is adapted to abut against an inner end surface of the second end of the sleeve. When the boss abuts against the inner end face of the second end of the outer sleeve, the end of the first part abuts against the needle core, so that the stop portion and the stop platform are spaced apart by a distance.

17. The lancet of claim 1 wherein, The first end of the outer sleeve is provided with a stop rib, which is suitable for preventing the key cap from moving towards the needle outlet.

18. The lancet of claim 1 wherein, The cross-sectional area of the outer sleeve gradually decreases from the first end to the second end.

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