Injection pen capable of preventing needle stick injury

Abstract

The utility model provides a needle-stick-injury-preventing injection pen which comprises an injection pen body, a needle head installed at the front end of the injection pen body and a needle head sleeve arranged outside the injection pen body in a sleeved mode, and the outer wall of the injection pen body is provided with a device capable of being detached from the needle head sleeve. In an initial state, the needle sleeve is connected with the injection pen main body through the first connecting section, and the needle is exposed for injection; after injection, the needle sleeve is disconnected from the first connecting section and only connected with the second connecting section by operating the needle sleeve, and the needle sleeve can be arranged outside the needle in a surrounding mode so as to cover the needle. The needle is covered by the needle sleeve, accidental puncture is effectively prevented, and particularly in a medical environment, the risk of puncture injury caused by careless operation of medical staff is reduced, cross infection is reduced, and the health of the medical staff and patients is enhanced. The needle head sleeve is arranged to achieve the purpose of preventing the needle injury, and the needle head sleeve is simple in structure, low in cost and beneficial to popularization and use.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of medical apparatus and instruments, and particularly relates to a needle-stick injury prevention injection pen. BACKGROUND

[0002] Pen injectors (i.e. injection pens) are used to treat various types of diseases, including diabetes, growth hormone deficiency and infertility, and are mainly applied in medical sites such as hospitals, clinics, retail pharmacies, and various medical processes such as vaccination, blood collection, intravenous injection, etc. The demand for pen injectors is very large because they are an important tool for treating many chronic diseases and can improve the quality of life of patients who need regular drug injections. Since diabetes is a chronic disease that usually requires regular insulin injections, pen injectors are usually used to inject insulin, so factors such as the rising prevalence of chronic diseases such as diabetes are also the main driving force for the market of pen injectors.

[0003] The needle-stick injury prevention pen is designed to improve safety during use and reduce the risk of needle stick injuries. CN201821833110.6 discloses a rotating insulin pen needle, an insulin injection needle head is provided with a needle head protection shell body outside, the insulin injection needle head is of telescopic structure, when the insulin injection needle head is needed, the needle head can be stretched out by pushing the needle head rotating fixing seat, after use, the insulin injection needle head can be retracted into the needle head protection shell body, preventing the needle head from being damaged and deformed, and preventing the used insulin injection needle head from injuring the hand during handling, making handling safer. However, the above-mentioned patent has the following technical problems:

[0004] 1) Complexity of operation. Compared with traditional injectors, its structure and operation process are still slightly complex, and the complexity of operation may cause certain trouble to the use of medical staff and patients, especially in emergency situations or for people who are not familiar with such equipment.

[0005] 2) Higher cost. Its structure is complex, and the number of parts is large, which increases the cost, and these additional costs may result in a higher price compared with traditional injectors, and high cost may limit the popularization and use in some medical institutions or areas with limited economic conditions. SUMMARY

[0006] The utility model aims at solving the technical problems existing in the prior art, and the purpose of the utility model is to provide a needle-stick injury prevention injection pen.

[0007] To achieve the above object, the utility model discloses the following technical scheme: a kind of anti-needle injury injection pen, including injection pen main body, needle installed in the front end of injection pen main body, and needle cover set in the outside of injection pen main body and with injection pen main body movably connected needle cover, the outer wall of injection pen main body has the first connecting section that can be detachably fixed with needle cover and the second connecting section located in the front side of first connecting section;Normal, needle cover is connected with first connecting section, needle is exposed, by operating needle cover, needle cover is disconnected with first connecting section and only connected with second connecting section, needle cover can be ringed in the outside of needle to cover needle.

[0008] The above technical scheme, by setting needle cover cover needle, effectively prevent accidental injury, especially in medical environment, this reduces the risk of needle injury caused by careless operation of medical staff, reduces cross infection, enhances the safety of medical staff and patient, protects the health of medical staff and patient.The utility model can achieve the purpose of preventing needle injury by setting needle cover, and the structure is simple, the cost is low, and it is beneficial to popularization and use, especially in some medical institutions or areas with limited economic conditions.

[0009] In a preferred embodiment of the utility model, first connecting section is equipped with first outer thread, and second connecting section is equipped with second outer thread, and the inner wall of needle cover rear section has first inner thread that can engage with first outer thread and second outer thread at different times.

[0010] The above technical scheme, needle cover is connected with injection pen main body by thread, and can be separated and connected by rotating mode, and the operation is simple and convenient;And injection pen main body is provided with first outer thread and second outer thread, for fixing the position of needle cover before and after use, and the thread is set in stages, compared with the whole thread, the present scheme can cover needle cover outside needle more quickly, save time.

[0011] In a preferred embodiment of the utility model, the inner wall of needle cover front section has second inner thread that can engage with second outer thread.

[0012] The above technical scheme, initially, the first outer thread and the second outer thread of injection pen main body are engaged with needle cover simultaneously, so that the connection between needle cover and injection pen main body is more firm.

[0013] In a preferred embodiment of the utility model, the needle tip of the needle head front end is a tip formed by five cutting surfaces, the five cutting surfaces include: a first cutting surface extending obliquely forward forming a first inclination angle with the axis of the needle head; two second cutting surfaces extending obliquely forward symmetrically arranged on both sides of the axis of the needle head connected with the first cutting surface, the second cutting surface forms a second inclination angle greater than the first inclination angle with the axis of the needle head; two third cutting surfaces extending obliquely forward symmetrically arranged on both sides of the axis of the needle head connected with the two second cutting surfaces, the distal ends of the two third cutting surfaces intersect to form a ridge, the third cutting surface forms a third inclination angle greater than the second inclination angle with the axis of the needle head.

[0014] The above technical scheme uses the needle tip of the needle head formed by five cutting surfaces, the number of sharp points is increased, the penetration resistance is reduced, the pressure generated when the needle tip contacts the skin can be dispersed more effectively, the damage to the skin tissue is reduced, the needle head is easier to enter the skin; and the possibility of deviation in the puncture process is reduced, and the stability of operation is improved.

[0015] In a preferred embodiment of the utility model, a color-changing label capable of being observed is arranged on the outer wall of the injection pen body, the needle cover is made of transparent material or has a perspective window made of transparent material; in a normal state, the needle cover is connected with the first connecting section, and the color-changing label displays a first color; when the needle cover is disconnected from the first connecting section, the color-changing label displays a second color.

[0016] The above technical scheme, the color-changing label being the first color not only indicates that the needle cover is tightly covered, but also plays a warning and reminding role; the color-changing label displaying the second color prompts that the needle cover can be freely slid on the injection pen body, and also indicates that the needle has been used. Through the change of color, the nursing staff can quickly judge the state of the needle cover, considering the high requirements for operation speed and accuracy in a medical environment, the visual prompt simplifies the operation process; and the obvious color distinction can also reduce the risk caused by misoperation and improve the overall safety in use.

[0017] In another preferred embodiment of the utility model, the color-changing label is blue litmus paper treated by alkaline, a storage capsule containing acidic substances is arranged at the connecting position of the needle cover and the first connecting section, when the needle cover is operated to disconnect from the first connecting section, the storage capsule is damaged to release the acidic substances therein to contact the color-changing label, so that the color-changing label changes from the first color to the second color.

[0018] The above technical scheme, when the injection pen is normally used, the nursing staff can observe the color of the color-changing label through the needle cover, which is blue to indicate that the needle has not been used; after the injection is completed, the needle cover is operated to disconnect from the first connecting section, at this time, the acidic substances in the storage capsule are released and contact the color-changing label, the color-changing label changes to red, which warns the nursing staff that the needle has been used and attention should be paid to needlestick injury.

[0019] In another preferred embodiment of the present application, the injection pen body comprises a needle cylinder, a piston located in the needle cylinder and sliding along the axial direction of the needle cylinder, and a piston rod connected with the piston and extending out of the rear end of the needle cylinder, the piston rod is fixedly connected with or detachably connected with the piston, the needle head is mounted at the front end of the needle cylinder, and the needle head sleeve is movably connected with the outer wall of the needle cylinder.

[0020] The above technical solution, when the piston rod is detachably connected with the piston, the injection pen can be self-destroyed by separating the piston rod from the piston, thereby preventing secondary use and reducing cross infection.

[0021] In another preferred embodiment of the present application, when the piston rod is detachably connected with the piston, the outer wall of the piston is fixedly connected with the inner wall of the needle cylinder in the circumferential direction, the piston rod is rotatable relative to the piston, the front end of the piston rod is a threaded stud, and the piston has a threaded hole capable of being threadedly connected with the threaded stud.

[0022] The above technical solution, the piston rod is threadedly connected with the piston or connected through a mortise and tenon structure, so that the separation operation of the piston rod and the piston is simple and easy to use.

[0023] In another preferred embodiment of the present application, the needle tip of the needle head is an insoluble needle tip made of stainless steel or a soluble needle tip made of a soluble medical material.

[0024] The above technical solution, according to the actual situation, an injection pen with an insoluble needle tip or an injection pen with a soluble needle tip is selected and configured to meet different use requirements.

[0025] In another preferred embodiment of the present application, the material of the soluble needle tip is dextran, mannitol, glucose, sodium hyaluronate or gelatin.

[0026] The above technical solution, the material of the soluble needle tip is soluble in blood, the metabolic process in the body is relatively stable, the toxicity is low, and the material can improve the microcirculation of blood vessels.

[0027] The additional aspects and advantages of the present application will be partially given in the following description, partially will become obvious from the following description, or will be understood through the practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0028] The above and / or additional aspects and advantages of the present application will become apparent and more readily appreciated from the following description of the embodiments, with reference to the following drawings:

[0029] Figure 1 is a structural schematic diagram of a pre-use structure of a needle-stick-proof injection pen of an embodiment.

[0030] Figure 2 is a structural schematic diagram of a post-use structure of a needle-stick-proof injection pen of an embodiment.

[0031] Figure 3 is a structural schematic diagram of a needle tip of a front end of a needle of an embodiment.

[0032] Figure 4 is a structural schematic diagram of a pre-use structure of a needle-stick-proof injection pen of an embodiment two.

[0033] Figure 5 is a structural schematic diagram of an injection pen body during injection of an embodiment three.

[0034] Figure 6 is a structural schematic diagram of an injection pen body after injection of an embodiment three.

[0035] Figure 7 is a structural schematic diagram of a piston rod and a piston separated of an embodiment three.

[0036] Figure 8 is a structural schematic diagram of an injection pen body during injection of an embodiment four.

[0037] Figure 9 is a structural schematic diagram of an injection pen body after injection of an embodiment four.

[0038] Figure 10 is a structural schematic diagram of a piston rod and a piston separated of an embodiment four.

[0039] Figure 11 is a bottom view of a piston of an embodiment four.

[0040] The reference signs in the drawings of the specification include: a needle cylinder 1, a first connecting section (first external thread) 11, a second connecting section (second external thread) 12, a piston 2, a threaded hole 21, a insertion hole 22, a vertical groove 23, a horizontal groove 24, a piston rod 3, a stud 31, a tenon 32, an operation part 4, a needle 5, a first cutting surface 51, a second cutting surface 52, a third cutting surface 53, a ridge 54, a needle cover 6, a first internal thread 61, a second internal thread 62, a color-changing label 7. DETAILED DESCRIPTION

[0041] Embodiments of the present application will be described in detail below, examples of which are shown in the drawings, wherein the same or similar reference signs represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the drawings are exemplary and are only used to explain the present application and cannot be understood as limiting the present application.

[0042] In the description of this utility model, it should be understood that the terms "longitudinal", "lateral", "vertical", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" 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 utility model 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 utility model.

[0043] In the description of this utility model, unless otherwise specified and limited, it should be noted that the terms "installation", "connection" and "linking" should be interpreted broadly. For example, they can refer to mechanical or electrical connections, or internal connections between two components. They can be direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0044] Example 1

[0045] This embodiment provides an injection pen that prevents needlestick injuries, such as... Figure 1 and Figure 2 As shown, in a preferred embodiment, the injection pen includes an injection pen body, a needle 5 mounted on the front end of the injection pen body, and a tubular needle sleeve 6 that is sleeved outside the injection pen body and movably connected to the injection pen body. The injection pen body can employ existing technology, for example, it may include a syringe 1, a piston 2 located inside the syringe 1 and sliding along the axial direction of the syringe 1, and a piston rod 3 fixed to (e.g., welded or glued) the rear end of the piston 2 and extending to the rear end of the syringe 1. The piston rod 3 has an operating part 4 at its end. The needle 5 is mounted on the front end of the syringe 1, and the needle sleeve 6 is movably connected to the outer wall of the syringe 1.

[0046] In this invention, the outer wall of the syringe 1 of the injection pen body has a first connecting section 11 that can be detachably fixed to the needle tip sleeve 6, and a section located on the front side of the first connecting section 11. Figure 1 The second connecting segment 12 (shown above). Figure 1 As shown, initially, the needle cap 6 is connected to the main body of the injection pen via the first connecting section 11, with the needle 5 exposed, which does not affect the injection operation (aspiration, medication) of the injection pen; as Figure 2 As shown, after injection, when the needle cap 6 is disconnected from the first connecting section 11 and connected only to the second connecting section 12 by operating the needle cap 6, the needle cap 6 can surround the needle 5 to cover the needle 5, preventing the needle 5 from being damaged or deformed, and preventing the needle 5 of the used injection pen from pricking the hand during handling, making the handling safer.

[0047] In a preferred embodiment, the first connecting section 11 of the needle cylinder 1 is provided with a first external thread, the second connecting section 12 is provided with a second external thread, the first external thread 11 and the second external thread 12 are arranged on the outer wall of the needle cylinder 1, the outer wall of the needle cylinder 1 between the first external thread 11 and the second external thread 12 is a smooth rod, the first external thread 11 and the second external thread 12 have the same rotation direction, helix angle and pitch, and the rear end of the needle sleeve 6 is provided with a first internal thread 61 capable of engaging with the first external thread 11 and the second external thread 12 at different times.

[0048] As shown in Figure 1 the initial state, the first internal thread 61 of the rear end of the needle sleeve 6 engages with the first external thread 11 on the outer wall of the needle cylinder 1 to fix the needle sleeve 6 on the needle cylinder 1, at this time the needle 5 is exposed and does not affect the use of the injection pen; after injection, hold the needle cylinder 1, rotate the needle sleeve 6 to make the first internal thread 61 disengage from the first external thread 11, then slide the needle sleeve 6 forward to make the first internal thread 61 contact with the second external thread 12, and then rotate the needle sleeve 6, the first internal thread 61 of the rear end of the needle sleeve 6 engages with the second external thread 12 on the outer wall of the needle cylinder 1 to fix the position of the needle sleeve 6, at this time the needle 5 is covered by the needle sleeve 6.

[0049] Preferably, the inner wall of the front section of the needle sleeve 6 is provided with a second internal thread 62 capable of engaging with the second external thread 12. Initially, the first internal thread 61 of the rear section of the needle sleeve 6 engages with the first external thread 11 of the needle cylinder 1, and at the same time the second internal thread 62 of the front section of the needle sleeve 6 engages with the second external thread 12 of the needle cylinder 1, the two threaded connections make the connection between the needle sleeve 6 and the needle cylinder 1 more firm.

[0050] The needle tip of the needle 5 of the utility model is made of stainless steel and is not soluble, or is made of soluble medical material. The soluble needle tip is made of compressed dextran powder, which is beneficial to realize that the needle tip can be blunt or even melt into blood in about 20 seconds after entering the blood of the patient, and reduce the possibility of subcutaneous hemorrhage caused by piercing the other blood vessel. Of course, the material of the soluble needle tip can also be mannitol, glucose, sodium hyaluronate or gelatin, etc.

[0051] As shown in Figure 3As shown, in another preferred embodiment, the needle tip of the front end of the needle 5 is a tip formed by five facets, including: a first facet 51, two second facets 52 and two third facets 53. The first facet 51 forms a first inclination angle with the axis of the needle 5 and extends obliquely forward; the two second facets 52 are respectively connected to the two sides of the first facet 51 and extend obliquely forward, the two second facets 52 are symmetrically arranged on the two sides of the axis of the needle 5, and the second facet 52 forms a second inclination angle greater than the first inclination angle with the axis of the needle 5; the two third facets 53 are respectively connected to the two second facets 52 and extend obliquely forward, the two third facets 53 are symmetrically arranged on the two sides of the axis of the needle 5, and the distal ends of the two third facets 53 intersect to form a ridge 54, and the third facet 53 forms a third inclination angle greater than the second inclination angle with the axis of the needle 5. It should be noted that, especially when the needle tip of the needle 5 is made of stainless steel, the needle tip is a tip formed by five facets.

[0052] The needle 5 of the utility model adopts a needle tip formed by five facets, the number of sharp points is increased, the penetration resistance is reduced, the pressure generated when the needle tip contacts the skin can be more effectively dispersed, the damage to the skin tissue is reduced, the needle 5 is more easily inserted into the skin; and the possibility of deviation in the puncture process is reduced, and the stability of operation is improved.

[0053] Embodiment two

[0054] The structural principle of the embodiment is basically the same as that of embodiment one, and the difference lies in that, as shown in the figure, Figure 4 In this embodiment, the outer wall of the needle barrel 1 of the injection pen body is provided with an observable color-changing label 7, and specifically, the needle cover 6 can be made of transparent material, or the needle cover 6 has a perspective window made of transparent material, so that people can conveniently observe the color-changing label 7. In the normal state (initial state), the needle cover 6 is connected with the first connecting section 11, the color-changing label 7 displays a first color (such as blue), which represents that the needle cover 6 has not been rotated; when the needle cover 6 is rotated to be loosened, the color-changing label 7 displays a second color (such as red), which prompts that the needle cover 6 can be freely slid on the needle barrel 1. The blue color of the color-changing label 7 not only indicates that the needle cover 6 has been tightly covered, but also plays a warning and reminding role, helping nursing staff to quickly judge the state of the needle cover 6.

[0055] The color-changing label 7 is made of alkaline-treated blue litmus paper. A reservoir containing acidic substance (not shown) is installed at the connection between the needle tip sleeve 6 and the first connecting section 11. When the needle tip sleeve 6 is disconnected from the first connecting section 11 by operating it, the reservoir ruptures, releasing the acidic substance, which then comes into contact with the color-changing label 7, causing it to change from a first color (blue) to a second color (red). This clear color distinction reduces the risk of misoperation and improves overall safety. Preferably, the color-changing label 7 is made of a wear-resistant and corrosion-resistant material to maintain its long-term readability and durability.

[0056] Specifically, a pre-treated color-changing label 6 (made of alkaline-treated blue litmus paper) is affixed to a suitable position on the outer wall of the syringe 1 of the injection pen. A reservoir containing acidic substance is installed at the connection between the needle cap 6 and the first connecting section 11, ensuring a good seal to prevent premature leakage of the acidic substance. During normal use of the injection pen, medical personnel can observe the color of the color-changing label 7 through the needle cap 6; blue indicates that the needle cap 6 is tightened and the needle 5 is not in use. After injection, the needle cap 6 is rotated to disconnect it from the first connecting section 11. At this time, the reservoir ruptures, releasing the acidic substance, and the color-changing label 6 turns red, warning medical personnel that the needle 5 has been used and to be careful to avoid needlestick injuries. Afterward, the needle cap 6 is connected to the second connecting section 12 to cover the needle and prevent needlestick injuries.

[0057] Example 3

[0058] The structural principle of this embodiment is basically the same as that of Embodiments 1 and 2, except that the piston rod 3 and piston 2 are not fixedly connected as a single unit, but are detachably connected. Figures 5-7 As shown, in this embodiment, the outer wall of the piston 2 is circumferentially fixed to the inner wall of the syringe 1. For example, the inner wall of the syringe 1 has a groove extending along its axial direction, and the outer wall of the piston 2 has a sliding post that can be inserted into the groove and slide in the groove. This allows the piston 2 to slide back and forth in the syringe 1 but not to rotate circumferentially. The piston rod 3 can rotate relative to the piston 2. The front end of the piston rod 3 is a stud 31 with external threads. The piston 2 has a threaded hole 21 that can be threadedly connected to the stud 31. The threaded hole 21 is a blind hole.

[0059] In its normal (initial) state, the stud 31 at the front end of the piston rod 3 is threadedly connected to the threaded hole 21 of the piston 2, fixing the piston rod 3 and piston 2 and not affecting the injection function of the pen. The injected medication can be pre-filled into the syringe 1, or drawn into the syringe 1 by pulling the piston rod 3 backward during use. During injection, the operating part 4 causes the piston rod 3 to push the piston 2 forward within the syringe 1, and the medication is ejected from the needle 5 for injection. After injection, rotating the operating part 4 rotates the piston rod 3, preventing the piston 2 from rotating with the piston rod 3. This separates the stud 31 from the threaded hole 21, thus detaching the piston rod 3 and piston 2 for self-destruction, preventing the pen from being reused and reducing the possibility of disease transmission.

[0060] Example 4

[0061] The structural principle of this embodiment is basically the same as that of Embodiment 3, except that the connection between piston rod 3 and piston 2 is different. Figures 8-11 As shown, in this embodiment, the outer wall of the piston 2 is also circumferentially fixed to the inner wall of the syringe 1, and the piston rod 3 can also rotate relative to the piston 2. The outer wall at the front end of the piston rod 3 is provided with an outwardly protruding tenon 32. Preferably, multiple tenons 32 are circumferentially spaced, such as three tenons 32. The piston 2 has an axially extending rearward insertion hole 22. The side wall of the insertion hole 22 has a mortise groove that can be engaged and fixed with the tenon 32. The mortise groove is an L-shaped groove, including an axially extending vertical groove 23 and a circumferentially extending horizontal groove 24 communicating with the front end of the vertical groove 23. The front end of the piston rod 3 can be inserted into the insertion hole 22, and the tenon 32 can enter the horizontal groove 24 through the vertical groove 23 and be engaged and fixed with the horizontal groove 24, or disengage from the mortise groove. Preferably, the tenon 32 is integrally connected to the mortise groove, or only to the horizontal groove 24 of the mortise groove. Without external force, the piston rod 3 will not rotate relative to the piston 2.

[0062] Under normal conditions, the front end of the piston rod 3 is inserted into the insertion hole 22, and the tenon 32 is located in the transverse groove 24 of the mortise and is engaged and fixed therewith, thus fixing the piston rod 3 and the piston 2 and not affecting the injection function of the injection pen. After injection, rotating the operating part 4 rotates the piston rod 3. The piston 2 does not rotate with the piston rod 3. The tenon 32 rotates and exits the transverse groove 24 and enters the front end of the vertical groove 23. Pulling the piston rod 3 backward along the direction of the vertical groove 23 causes the tenon 32 to fall out of the mortise and the piston rod 3 and piston 2 to separate, thus self-destructing and preventing the injection pen from being reused, reducing the possibility of disease transmission.

[0063] In the description of the present specification, the description with reference to the terms "preferred embodiment", "one embodiment", "some embodiments", "an example", "a specific example" or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily mean the same embodiment or example. Furthermore, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0064] Although the embodiments of the present application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made thereto without departing from the principles and spirit of the present application, and the scope of the present application is defined by the claims and their equivalents.

Claims

1. A needle stick injury proof injection pen characterized by, The injection pen comprises a pen body, a needle mounted on the front end of the pen body, and a needle cover which is sleeved on the pen body and movably connected with the pen body, wherein the outer wall of the pen body is provided with a first connecting section and a second connecting section located on the front side of the first connecting section, and the first connecting section can be detachably connected with the needle cover. In normal state, the needle cover is connected with the first connecting section, and the needle is exposed, and the needle cover is disconnected from the first connecting section and connected with the second connecting section by operating the needle cover, and the needle cover can be sleeved on the needle to cover the needle.

2. A needlestick-injury-proof injection pen according to claim 1, characterized in that The first connecting section is provided with a first external thread, the second connecting section is provided with a second external thread, and the inner wall of the rear section of the needle cover is provided with a first internal thread which can be engaged with the first external thread and the second external thread at different times.

3. A needlestick-injury-proof injection pen according to claim 2, characterized in that The inner wall of the front section of the needle cover is provided with a second internal thread which can be engaged with the second external thread.

4. The needlestick-injury-proof injection pen according to claim 1, characterized in that The tip of the needle is a pointed end formed by five cutting surfaces, and the five cutting surfaces comprise: a first cutting surface which extends obliquely forward and forms a first inclination angle with the axis of the needle; two second cutting surfaces which extend obliquely forward and are symmetrically arranged on both sides of the axis of the needle and are connected with the first cutting surface, and the second cutting surfaces form a second inclination angle which is larger than the first inclination angle with the axis of the needle; two third cutting surfaces which extend obliquely forward and are symmetrically arranged on both sides of the axis of the needle and are connected with the two second cutting surfaces respectively, and the distal ends of the two third cutting surfaces intersect to form a ridge, and the third cutting surfaces form a third inclination angle which is larger than the second inclination angle with the axis of the needle.

5. The needlestick injury preventing injection pen according to claim 1, wherein The outer wall of the pen body is provided with an observable color-changing label, and the needle cover is made of transparent material or has a perspective window made of transparent material. In normal state, the needle cover is connected with the first connecting section, and the color-changing label displays a first color. When the needle cover is disconnected from the first connecting section, the color-changing label displays a second color.

6. A needlestick-injury-proof injection pen according to claim 5, characterized in that The color-changing label is blue litmus paper treated by alkaline, and a storage capsule containing acidic substances is mounted at the connection between the needle cover and the first connecting section. When the needle cover is disconnected from the first connecting section by operating the needle cover, the storage capsule is damaged to release the acidic substances therein to contact with the color-changing label, so that the color-changing label changes from the first color to the second color.

7. A needlestick-injury -proof injection pen according to any one of claims 1-6, characterized in that The injection pen comprises a needle cylinder, a piston which is slidably arranged in the needle cylinder along the axial direction of the needle cylinder, and a piston rod which is connected with the piston and extends to the rear end of the needle cylinder, wherein the piston rod is fixedly connected or detachably connected with the piston, the needle is mounted on the front end of the needle cylinder, and the needle cover is movably connected with the outer wall of the needle cylinder.

8. A needlestick-injury-proof injection pen according to claim 7, characterized in that When the piston rod is detachably connected with the piston, the outer wall of the piston is fixedly connected with the inner wall of the needle cylinder in the circumferential direction, the piston rod can rotate relative to the piston, the front end of the piston rod is a threaded stud with external threads, and the piston has a threaded hole which can be threadedly connected with the threaded stud. Or the outer wall of the piston is circumferentially fixed with the inner wall of the syringe, the piston rod can rotate relative to the piston, the outer wall of the front end of the piston rod is provided with a tenon protruding outward, the piston has an axially extending insertion hole, the side wall of the insertion hole has a mortise capable of being clamped with the tenon, the front end of the piston rod can be inserted into the insertion hole, and the tenon can be clamped with or separated from the mortise.

9. A needlestick-injury -proof injection pen according to any one of claims 1-6, characterized in that The needle tip of the needle is a non-dissolvable needle tip made of stainless steel or a dissolvable needle tip made of a dissolvable medical material.

10. A needlestick-injury-proof injection pen according to claim 9, characterized in that The material of the dissolvable needle tip is dextran, mannitol, glucose, sodium hyaluronate or gelatin.

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