Automatic injection pen with floating needle head

Abstract

The present invention proposes an automatic injection pen with a floating needle, comprising a housing arranged along a longitudinal axis and having a proximal end and a distal end, a syringe body sleeved with a needle protective sleeve that is selectively axially displaceable relative to the housing along the longitudinal axis, an injection mechanism is arranged at the end, away from the near body, of the needle head protection sleeve and located in the containing cavity of the shell, and the injector body can move in the axial direction of the shell. The needle head protection sleeve can move in the axial direction of the shell, and when the needle head protection sleeve moves to a first position relative to the shell, the needle is exposed relative to the needle head protection sleeve; when the needle head protection sleeve continues to move from the first position relative to the shell, the needle head protection sleeve and the injector body move synchronously, so that the needle exposure distance is kept at the set distance till the triggering action of the injection mechanism is triggered.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and more specifically, to an automatic injection pen with a floating needle tip. Background Art

[0002] With the explosive growth of the population and the siphon effect of cities, medical resources are becoming increasingly scarce. The management of chronic diseases will occupy a large amount of medical resources, resulting in huge economic costs. Society has put forward higher requirements for injection devices for self-use by patients. People hope that the injection device is as simple as possible to operate and does not require special training. Traditional injection devices usually require proficiency in the injection angle and depth, and manual injection. The injection effect of drugs will vary to a certain extent due to the proficiency of the user. With the development of pharmaceutical technology, more and more chronic diseases adopt cyclic drug administration. The traditional injection method is cumbersome and complex, and patients may forget the usage steps before each injection, resulting in the drug being unable to exert its due effect.

[0003] The emergence of automatic injection devices provides an effective solution to this problem. People hope that the injection device is simple to operate, has high patient compliance, and has multi-dimensional feedback during the injection process, such as auditory, visual, and tactile. Patients can control the entire injection process by obtaining feedback signals, reducing anxiety and enhancing confidence; at the same time, the injection depth is stable and consistent, without the need for patients to adjust, and the needle tip is avoided from being exposed before and after injection to cause fear to patients; the injection process does not require manual injection and the injection time is reasonable; after the injection is completed, it should also have functions such as anti-mishandling and / or anti-reuse. At the same time, people pay more attention to personal privacy issues and put forward higher requirements for the miniaturization, portability, and usability of products. How to achieve the above functions and performances to meet market demands has attracted more and more attention from engineering and technical personnel.

[0004] Currently, the existing patent number 2023109385598 discloses an automatic injection pen, including a prefilled syringe module. A guide groove is provided at the guide sleeve, and a wing-shaped structure corresponding to the guide groove is provided at the push rod. A shrapnel is provided at the trigger sleeve, and a rib position is provided corresponding to the wing-shaped structure. When the injection pen is in use, the shrapnel opens and the trigger sleeve moves downward. The trigger slope of the rib position pushes the wing-shaped structure so that the wing-shaped structure can slide in the guide groove, and the injection spring pushes the push rod for injection.

[0005] However, for this disposable automatic injection pen, since the position of the needle tip is only determined by its own processing error and the processing error of the needle tip protection sleeve, in order to ensure normal triggering, the actual stroke of the injection pen is often slightly greater than the stroke at the triggering position, and there is also a certain stroke during the triggering process. Due to this design, users often continue to press the needle tip protection sleeve to the maximum stroke after the syringe is triggered for injection, which may lead to some pain situations. Summary of the Invention

[0006] In view of the above, the present invention provides an automatic injection pen with a floating needle, comprising a housing 4 which is arranged along a longitudinal axis and has a proximal end and a distal end. The housing 4 is used to accommodate a syringe and a needle protection sleeve 2. The syringe comprises a syringe body 3 and a needle 32 at the front end. The syringe body 3 is sleeved with the needle protection sleeve 2. The needle protection sleeve 2 can selectively axially displace relative to the housing 4 along the longitudinal axis. An injection mechanism 5 for triggering an injection action is provided at a position away from the proximal end of the needle protection sleeve 2. The injection mechanism 5 is located in the accommodation chamber of the housing 4. The syringe body 3 is movable along the axial direction of the housing 4; the needle protection sleeve 2 is movable along the axial direction of the housing 4. When the needle protection sleeve 2 moves relative to the housing 4 to a first position, the needle 32 is exposed relative to the needle protection sleeve; when the needle protection sleeve 2 continues to move relative to the housing 4 from the first position, the needle protection sleeve 2 moves synchronously with the syringe body 3, so that the exposed distance of the needle 32 is maintained at a set distance until the triggering action of the injection mechanism 5 is triggered.

[0007] An automatic injection pen with a floating needle, comprising a housing 4 which is arranged along a longitudinal axis and has a proximal end and a distal end. The housing 4 is used to accommodate a syringe and a needle protection sleeve 2. The syringe comprises a syringe body 3 and a needle 32 at the front end. The syringe body 3 is sleeved with the needle protection sleeve 2. The needle protection sleeve 2 can selectively axially displace relative to the housing 4 along the longitudinal axis. An injection mechanism 5 for triggering an injection action is provided at a position away from the proximal end of the needle protection sleeve 2. The injection mechanism 5 is located in the accommodation chamber of the housing 4, and is characterized in that: the syringe body 3 is movable along the axial direction of the housing 4; the needle protection sleeve 2 is movable along the axial direction of the housing 4. When the needle protection sleeve 2 moves relative to the housing 4 to a first position, the needle 32 is exposed relative to the needle protection sleeve; when the needle protection sleeve 2 continues to move relative to the housing 4 from the first position, the needle protection sleeve 2 moves synchronously with the syringe body 3, so that the exposed distance of the needle 32 is maintained at a set distance until the triggering action of the injection mechanism 5 is triggered.

[0008] Further, a piston 34 is provided in the syringe body 3. A push rod 6 is sleeved at the bottom of the syringe body 3. The push rod 6 can slide in the syringe. A gap is provided between the piston 34 and the push rod 6 to ensure that before the needle protection sleeve 2 and the syringe body 3 move synchronously to trigger the injection mechanism 5, the push rod 6 does not contact the piston 34 and push the piston 34 to cause some liquid medicine to overflow.

[0009] Further, in order to ensure the triggering action of the injection mechanism 5, during the movement stroke of the needle protection sleeve 2, the total movement stroke of the needle protection sleeve 2 is greater than the stroke of the needle protection sleeve 2 driving the syringe body 3 together to the triggering position.

[0010] Further, the needle protection sleeve 2 drives the syringe body 3 to move synchronously along the axis direction of the housing 4. The needle protection sleeve 2 and the syringe body 3 remain relatively stationary, and the distance between them is constant; the depth of the injection needle 32 inserted into the skin remains unchanged.

[0011] In some embodiments, ribs 21 are provided on the inner wall of the needle protection sleeve 2. There is a gap between the syringe body 3 and the injection mechanism 5, and an elastomer 15 is provided at the gap. During the injection process, when the needle protection sleeve 2 moves backward, the needle 32 moves to a preset distance relative to the needle protection sleeve 2. The ribs 21 cooperate with the syringe body 3, and the needle protection sleeve 2 and the needle 32 move synchronously. The elastomer 15 between the syringe body 3 and the injection mechanism 5 is compressed until the injection mechanism 5 is triggered to act. Finally, the user presses to the maximum limit position. During this process, since the needle protection sleeve 2 and the syringe body 3 always remain relatively stationary, the insertion depth does not change. In addition, during this process, slight back-and-forth shaking of the user will not change the insertion depth of the needle. Therefore, this can effectively improve the user's injection experience and reduce some pain. After the injection is completed, the forward movement of the needle protection sleeve 2 covers the needle 32.

[0012] Further, a needle 32 is installed at the front end of the syringe body 3, and the rear end is a mounting seat 31 protruding from the syringe body 3. The mounting seat 31 abuts against the inner wall of the needle protection sleeve 2.

[0013] Further, the backward movement of the needle protection sleeve 2 causes the ribs 21 to contact the mounting seat 31, and the syringe body 3 is driven to move together by pushing the mounting seat 31.

[0014] Further, there is a cooperation point between the mounting seat 31 and the ribs 21. The preset distance that the needle 32 exposes from the needle protection sleeve 2 is the length of the needle 32 and this cooperation point minus the length of the skin contact surface of the needle protection sleeve 2 and this cooperation point. By designing the length of the needle 32 and this cooperation point or the length of the skin contact surface of the needle protection sleeve 2 and this cooperation point, the preset distance that the needle 32 exposes from the needle protection sleeve 2 can be correspondingly adjusted.

[0015] In some embodiments, the ribs 21 are distributed around the inner wall of the needle protection sleeve 2 for one week. There are at least two ribs 21 and the ribs 21 are symmetrically arranged. The symmetrical arrangement can push the syringe body 3 to move together more stably.

[0016] Furthermore, the number of the ribs 21 is 2 - 6, and preferably 4.

[0017] In some embodiments, the distance of the gap between the syringe body 3 and the injection mechanism 5 is such that it is convenient to complete triggering the injection mechanism 5.

[0018] In some embodiments, there is a gap between the syringe body 3 and the injection mechanism 5. An elastomer 15 is provided at the gap. The needle protection sleeve 2 has two notches 22. There is a circumferential step 23 in the notches 22. The front end of the syringe body 3 is equipped with a needle 32, and the rear end is a mounting seat 31 protruding from the syringe body 3. The mounting seat 31 is placed in the notches 22. When the step 23 of the needle protection sleeve 2 contacts the mounting seat 31, the needle protection sleeve 2 drives the syringe body 3 to move together, so that the exposed distance of the needle 32 is maintained at a set distance. At this time, when continuing to move together, the elastomer 15 between the syringe body 3 and the injection mechanism 5 starts to be compressed until the injection mechanism 5 is triggered to act. Finally, the user presses to the maximum limit position. During this process, since the needle protection sleeve 2 and the syringe body 3 always remain relatively stationary, the penetration depth does not change. In addition, during this process, slight back-and-forth shaking by the user will not change the penetration depth of the needle. Therefore, this can effectively improve the injection experience of the user and relieve some pain. After the injection is completed, the forward displacement of the needle protection sleeve 2 covers the needle 32.

[0019] Furthermore, the needle protection sleeve 2 has a post-trigger travel section. The post-trigger travel section includes: the first-stage travel: after triggering the injection mechanism 5, the needle protection sleeve 2 axially displaces backward by a preset gap amount ΔL. The ΔL is used to compensate for manufacturing tolerances and assembly errors; the second-stage travel: within the range of the ΔL displacement, the needle protection sleeve 2 and the syringe body 3 move synchronously, and the axial distance between the two is constant to ensure that the penetration depth of the injection needle 32 into the skin remains unchanged.

[0020] In some embodiments, there is a gap between the syringe body 3 and the injection mechanism 5, and an elastomer 15 is provided at the gap. A window 12 is sleeved outside the syringe body 3, and the window 12 is installed in the housing 4. The window 12 axially limits the syringe body 3. The needle protection sleeve 2 has two notches 22, and there is a circumferential step 23 in the notches 22. The window 12 is provided with a clamping seat 13. When the step 23 of the needle protection sleeve 2 contacts the clamping seat 13, the needle protection sleeve 2 drives the window 12 to move together, so that the exposed distance of the needle 32 is maintained at a set distance. At this time, when continuing to move together, the elastomer 15 between the syringe body 3 and the injection mechanism 5 starts to be compressed until the injection mechanism 5 is triggered to act. Finally, the user presses to the maximum limit position. During this process, since the needle protection sleeve 2 and the syringe body 3 always remain relatively stationary, the penetration depth no longer changes. In addition, during this process, slight back-and-forth shaking by the user will not change the penetration depth of the needle. Therefore, this can effectively improve the user's injection experience and reduce some pain. After the injection is completed, the forward displacement of the needle protection sleeve 2 covers the needle 32.

[0021] In some embodiments, there is a gap between the syringe body 3 and the injection mechanism 5, and an elastomer 15 is provided at the gap. A window 12 is sleeved outside the syringe body 3, and the window 12 is installed in the housing 4. The window 12 axially limits the syringe body 3. The window 12 and the needle protection sleeve 2 have two hollow structures 24, and there is a clamping surface 25 in the hollow structures 24. A clamping block 14 is provided on the outer side wall of the window 12. When the clamping surface 25 of the needle protection sleeve 2 contacts the clamping block 14, the needle protection sleeve 2 drives the window 12 to move together, so that the exposed distance of the needle 32 is maintained at a set distance. At this time, when continuing to move together, the elastomer 15 between the syringe body 3 and the injection mechanism 5 starts to be compressed until the injection mechanism 5 is triggered to act. Finally, the user presses to the maximum limit position. During this process, since the needle protection sleeve 2 and the syringe body 3 always remain relatively stationary, the penetration depth no longer changes. In addition, during this process, slight back-and-forth shaking by the user will not change the penetration depth of the needle. Therefore, this can effectively improve the user's injection experience and reduce some pain. After the injection is completed, the forward displacement of the needle protection sleeve 2 covers the needle 32.

[0022] Further, the window 12 axially limits the syringe body 3 in at least one of the following ways. One way is as follows: A needle 32 is installed at the front end of the syringe body 3, a connection surface 33 is provided near the needle 32, the rear end is a mounting seat 31 protruding from the syringe body 3, a clamping claw 16 is provided at the upper part of the window 12, and the clamping claw 16 is clamped with the clamping surface 25 of the syringe body 3, so that the clamping surface 25 of the syringe body 3 is axially limited at the clamping claw 16. Another way is as follows: A needle 32 is installed at the front end of the syringe body 3, a connection surface 33 is provided near the needle 32, the rear end is a mounting seat 31 protruding from the syringe body 3, a groove 26 is provided at the lower part of the window 12, and the groove 26 is clamped with the mounting seat 31, so that the groove 26 axially limits the mounting seat 31 of the syringe body 3.

[0023] Further, the distance of the gap between the syringe body 3 and the injection mechanism 5 is set between 0.5 - 5 mm, and the recommended value is 1.5 mm.

[0024] In some embodiments, the elastic force of the elastomer 15 in the initial state is greater than the force of the needle 32 piercing the skin, ensuring that the needle 32 can pierce into the skin before the elastomer 15 deforms.

[0025] In some embodiments, the injection mechanism 5 includes a push rod 6 sleeved on the bottom of the syringe body 3. The push rod 6 can slide within the syringe. An injection spring 7 is sleeved within the push rod 6. A spring frame 10 passes through the injection spring 7. The spring frame 10 includes a spring guide rod structure 1011 disposed in the middle of the spring frame 10 and spring arms disposed on both sides of the spring frame 10. A hook 1012 is provided at the top of the spring arm. The spring guide rod structure 1011 passes through the interior of the injection spring 7, such that one end of the injection spring 7 abuts against the push rod 6 and the other end abuts against the spring frame 10. A guide sleeve 8 is sleeved outside the spring frame 10. A platform structure 81 is provided at the upper part of the guide sleeve 8. Before the injection pen is used, the platform structure 81 is engaged with the hook 1012. A guide groove 82 is further provided at the guide sleeve 8. A wing-shaped structure 61 corresponding to the guide groove 82 is provided at the push rod 6. A trigger sleeve 9 is sleeved outside the guide sleeve 8. The upper end of the trigger sleeve 9 abuts against the needle protection sleeve 22. A spring piece 91 is provided at the trigger sleeve 9 corresponding to the platform structure 81. A first protrusion 92 is provided on the inner wall of the spring piece 91 and abuts against the hook 1012. A rib 93 is provided at the trigger sleeve 9 corresponding to the wing-shaped structure 61. A return spring 11 is sleeved outside the trigger sleeve 9. During the use of the injection pen, when the needle protection sleeve 22 pushes the trigger sleeve 9 downward, the spring piece 91 opens under the interaction of the first protrusion 92 and the hook 1012, causing the trigger sleeve 9 to move downward. The rib 93 pushes the wing-shaped structure 61, enabling the wing-shaped structure 61 to slide within the guide groove 82. The injection spring 7 pushes the push rod 6 for injection. At the same time, the spring frame 10 moves downward, and the injection ends.

[0026] Advantages of the present invention: The present invention provides an automatic injection pen with a floating needle, including a housing 4. The housing 4 is arranged along a longitudinal axis and has a proximal end and a distal end. The housing 4 is used to accommodate a syringe and a needle protection sleeve 2. The syringe includes a syringe body 3 and a needle 32 at the front end. The syringe body 3 is sleeved with the needle protection sleeve 2. The needle protection sleeve 2 can selectively axially displace relative to the housing 4 along the longitudinal axis. An injection mechanism 5 for triggering an injection action is provided at the needle protection sleeve 2 away from the proximal end. The injection mechanism 5 is located within the accommodation chamber of the housing 4. The syringe body 3 is movable along the axial direction of the housing 4. The needle protection sleeve 2 is movable along the axial direction of the housing 4. When the needle protection sleeve 2 moves relative to the housing 4 to a first position, the needle 32 is exposed relative to the needle protection sleeve. When the needle protection sleeve 2 continues to move relative to the housing 4 from the first position, the needle protection sleeve 2 and the syringe body 3 move synchronously, such that the exposed distance of the needle 32 is maintained at a set distance until the trigger action of the injection mechanism 5 is triggered. Description of the Drawings

[0027] Figure 1 This is an exploded view of the overall injection pen of the present invention.

[0028] Figure 2 This is a cross-sectional view of the overall injection pen of the present invention.

[0029] Figure 3 is Figure 2 Local enlarged view A of

[0030] Figure 4 This is a structural diagram of the elastomer of the needle-floating automatic injection pen of the present invention.

[0031] Figure 5 This is a structural diagram of the needle protection sleeve of the needle-floating automatic injection pen of the present invention.

[0032] Figure 6 This is a top view of the needle protection sleeve of the needle-floating automatic injection pen of the present invention.

[0033] Figure 7 This is a structural diagram of the guide sleeve of the needle-floating automatic injection pen of the present invention.

[0034] Figure 8 This is a structural diagram of the spring holder of the needle-floating automatic injection pen of the present invention.

[0035] Figure 9 This is a structural diagram of the trigger sleeve of the needle-floating automatic injection pen of the present invention.

[0036] Figure 10 This is a cross-sectional view of the trigger sleeve of the needle-floating automatic injection pen of the present invention.

[0037] Figure 11 This is a structural diagram of the connection between the needle protection sleeve and the syringe body in Embodiment 2 of the needle-floating automatic injection pen of the present invention.

[0038] Figure 12 This is a structural diagram of the connection between the needle protection sleeve and the syringe body in Embodiments 3 and 4 of the needle-floating automatic injection pen of the present invention.

[0039] Figure 13 This is a structural diagram of the window in Embodiments 3 and 4 of the needle-floating automatic injection pen of the present invention.

[0040] Description of main component symbols

[0041] Window 12; Card seat 13; Snap block 14; Claw 16; Needle protection sleeve 2; Rib 21; Notch 22; Step 23; Hollow structure 24; Snap joint surface 25; Groove 26; Syringe body 3; Mounting seat 31; Needle 32; Connection surface 33; Piston 34; Housing 4; Injection mechanism 5; Push rod 6; Wing-shaped structure 61; Injection spring 7; Guide sleeve 8; Platform structure 81; Guide groove 82; Trigger sleeve 9; Elastic piece 91; First protrusion 92; Rib position 93; Spring holder 10; Spring guide rod structure 1011; Hook 1012; Return spring 11; Elastomer 15.

[0042] The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings. Specific embodiments Embodiment 1:

[0043] As Figures 1-6 shown, an automatic injection pen with a floating needle includes a housing 4, the housing 4 is arranged along a longitudinal axis and has a proximal end and a distal end, the housing 4 is used to accommodate a syringe and a needle protection sleeve 2, the syringe includes a syringe body 3 and a needle 32 at the front end, the syringe body 3 is sleeved with the needle protection sleeve 2, the needle protection sleeve 2 can selectively axially displace relative to the housing 4 along the longitudinal axis, the needle protection sleeve 2 is provided with an injection mechanism 5 for triggering an injection action away from the proximal end, the injection mechanism 5 is located in the accommodation chamber of the housing 4, and the syringe body 3 is movable along the axial direction of the housing 4; the needle protection sleeve 2 is movable along the axial direction of the housing 4, the inner wall of the needle protection sleeve 2 is provided with ribs 21, a gap is provided between the syringe body 3 and the injection mechanism 5, and an elastomer 15 is provided at the gap. During the injection process, when the needle protection sleeve 2 moves relative to the housing 4 to a first position, the needle protection sleeve 2 moves backward, and the needle 32 exposes relative to the needle protection sleeve 2. When the needle protection sleeve 2 continues to move relative to the housing 4 from the first position, at this time, the rib 21 cooperates with the syringe body 3, and the exposed distance between the needle protection sleeve 2 and the needle 32 remains unchanged and does not increase. Subsequently, synchronously, the elastomer 15 between the syringe body 3 and the injection mechanism 5 starts to be compressed until the injection mechanism 5 is triggered. After the injection is completed, the forward displacement of the needle protection sleeve 2 covers the needle 32.

[0044] After the injection mechanism 5 is triggered, when the user pushes the needle protection sleeve 2 to move back and forth in the axial direction within the stroke from the first position to the second position and to the maximum stroke, the needle protection sleeve and the syringe body 3 always move together, and the depth of the needle 32 inserted into the skin remains unchanged.

[0045] To ensure the triggering action of the triggering injection mechanism 5, during the movement stroke of the needle protection sleeve 2, the total movement stroke of the needle protection sleeve 2 is greater than the stroke of the needle protection sleeve 2 driving the syringe body 3 synchronously to the triggering position.

[0046] The needle protection sleeve 2 has a post-trigger stroke section, and the post-trigger stroke section includes: a first-stage stroke: after triggering the injection mechanism 5, the needle protection sleeve 2 axially displaces backward by a preset clearance amount ΔL, and the ΔL is used to compensate for manufacturing tolerances and assembly errors; a second-stage stroke: within the ΔL displacement range, the needle protection sleeve 2 and the syringe body 3 move synchronously, and the axial distance between the two is constant to ensure that the penetration depth of the injection needle 32 into the skin remains unchanged.

[0047] During this process, since the needle protection sleeve 2 and the syringe body 3 always remain relatively stationary, the penetration depth no longer changes. In addition, during this process, slight back-and-forth shaking by the user will not change the penetration depth of the needle 32. Therefore, this can effectively improve the user's injection experience and reduce some pain.

[0048] The front end of the syringe body 3 is equipped with a needle 32, and the rear end is a mounting seat 31 protruding from the syringe body 3. The mounting seat 31 abuts against the inner wall of the needle protection sleeve 2. The backward displacement of the needle protection sleeve 2 causes the rib 21 to contact the mounting seat 31, and the syringe body 3 is driven to move together by pushing the mounting seat 31. There is a cooperation point between the mounting seat 31 and the rib 21. The preset distance that the needle 32 protrudes from the needle protection sleeve 2 is the length of the needle 32 and the cooperation point minus the length of the skin contact surface of the needle protection sleeve 2 and the cooperation point. By designing the length of the needle 32 and the cooperation point or the length of the skin contact surface of the needle protection sleeve 2 and the cooperation point, the preset distance that the needle 32 protrudes from the needle protection sleeve 2 can be correspondingly adjusted. The ribs 21 are distributed around the inner wall of the needle protection sleeve 2. There are at least two ribs 21 and the ribs 21 are symmetrically arranged. Symmetrical arrangement can more stably drive the syringe body 3 to move together. The number of ribs 21 is 2 - 6, and preferably 4. The distance of the gap between the syringe body 3 and the injection mechanism 5 is such that it is convenient to complete the triggering of the injection mechanism 5. The distance of the gap between the syringe body 3 and the injection mechanism 5 is set between 0.5 - 5 mm, and the recommended value is 1.5 mm. The initial state elastic force of the elastomer 15 is greater than the force of the needle 32 piercing the skin, ensuring that the needle 32 can pierce the skin before the elastomer 15 deforms.

[0049] A piston 34 is provided inside the syringe body 3, and a push rod 6 is sleeved at the bottom of the syringe body 3. The push rod 6 can slide inside the syringe. There is a gap between the piston 34 and the push rod 6, ensuring that before the needle protection sleeve 2 and the syringe body 3 move synchronously to trigger the injection mechanism 5, the push rod 6 does not contact the piston 34 and push the piston 34 to cause some liquid medicine to overflow.

[0050] As Figures 7-10 shown, the injection mechanism 5 includes a push rod 6 sleeved at the bottom of the syringe body 3. The push rod 6 can slide inside the syringe. An injection spring 7 is sleeved inside the push rod 6, and a spring holder 10 penetrates through the injection spring 7. The spring holder 10 includes a spring guide rod structure 1011 provided in the middle of the spring holder 10 and spring arms provided on both sides of the spring holder 10. A hook 1012 is provided at the top of the spring arm. The spring guide rod structure 1011 passes through the inside of the injection spring 7, so that one end of the injection spring 7 abuts against the push rod 6 and the other end abuts against the spring holder 10. A guide sleeve 8 is sleeved outside the spring holder 10. A platform structure 81 is provided at the upper part of the guide sleeve 8. Before the injection pen is used, the platform structure 81 is engaged with the hook 1012. A guide groove 82 is also provided at the guide sleeve 8, and a wing-shaped structure 61 corresponding to the guide groove 82 is provided at the push rod 6. A trigger sleeve 9 is sleeved outside the guide sleeve 8. The upper end of the trigger sleeve 9 abuts against the needle protection sleeve 22. A spring piece 91 is provided at the trigger sleeve 9 corresponding to the platform structure 81. A first protrusion 92 is provided on the inner wall of the spring piece 91 and abuts against the hook 1012. A rib 93 is provided at the trigger sleeve 9 corresponding to the wing-shaped structure 61. A return spring 11 is sleeved outside the trigger sleeve 9. During the use of the injection pen, the needle protection sleeve 22 pushes the trigger sleeve 9 downward. The spring piece 91 opens under the interaction of the first protrusion 92 and the hook 1012, causing the trigger sleeve 9 to move downward. The rib 93 pushes the wing-shaped structure 61 so that the wing-shaped structure 61 can slide in the guide groove 82. The injection spring 7 pushes the push rod 6 for injection. At the same time, the spring holder 10 moves downward, and the injection is completed.

[0051] A gap is provided between the syringe body 3 and the trigger sleeve 9, and an elastic body 15 is provided at the gap. Embodiment 2:

[0052] As Figures 1-4 and Figure 11As shown, there is a gap between the syringe body 3 and the injection mechanism 5, and an elastomer 15 is provided in the gap. The needle protection sleeve 2 has two notches 22, and there is a circumferential step 23 in the notch 22. The front end of the syringe body 3 is equipped with a needle 32, and the rear end is a mounting seat 31 protruding from the syringe body 3. The mounting seat 31 is placed in the notch 22. When the needle protection sleeve 2 moves relative to the housing 4 and continues to move from the first position, the step 23 of the needle protection sleeve 2 contacts the mounting seat 31, and the needle protection sleeve 2 and the syringe body 3 move synchronously, so that the exposed distance of the needle 32 is maintained at a set distance. At this time, when they continue to move together, the elastomer 15 between the syringe body 3 and the injection mechanism 5 begins to be compressed until the injection mechanism 5 is triggered. Finally, the user presses to the maximum limit position. After the injection mechanism 5 is triggered, the needle protection sleeve and the syringe body 3 always move together, and the depth of the needle 32 piercing the skin remains unchanged.

[0053] To ensure the triggering action of the injection mechanism 5, during the movement stroke of the needle protection sleeve 2, the total movement stroke of the needle protection sleeve 2 is greater than the stroke of the needle protection sleeve 2 driving the syringe body 3 together to the triggering position.

[0054] The needle protection sleeve 2 has a post-trigger stroke section, and the post-trigger stroke section includes: First-stage stroke: After the injection mechanism 5 is triggered, the needle protection sleeve 2 moves backward along the axial direction by a preset clearance ΔL, and the ΔL is used to compensate for manufacturing tolerances and assembly errors; Second-stage stroke: Within the displacement range of ΔL, the needle protection sleeve 2 and the syringe body 3 move synchronously, and the axial distance between the two is constant to ensure that the depth of the injection needle 32 piercing the skin remains unchanged.

[0055] During this process, since the needle protection sleeve 2 and the syringe body 3 always remain relatively stationary, the piercing depth no longer changes. In addition, during this process, the slight back-and-forth shaking of the user will not change the piercing depth of the needle, so this can effectively improve the user's injection experience and reduce some pain. After the injection is completed, the forward displacement of the needle protection sleeve 2 covers the needle 32.

[0056] A piston 34 is provided in the syringe body 3, and a push rod 6 is sleeved at the bottom of the syringe body 3. The push rod 6 can slide in the syringe. There is a gap between the piston 34 and the push rod 6 to ensure that before the needle protection sleeve 2 and the syringe body 3 move synchronously to trigger the injection mechanism 5, the push rod 6 does not contact the piston 34 and push the piston 34 to cause some liquid medicine to overflow.

[0057] As Figures 7-10As shown, the distance of the gap between the syringe body 3 and the injection mechanism 5 is set between 0.5 - 5 mm, and the recommended value is 1.5 mm. The elastic force of the elastomer 15 in the initial state is greater than the force of the needle 32 piercing the skin, ensuring that the needle 32 can pierce into the skin before the elastomer 15 deforms. The injection mechanism 5 includes a push rod 6 sleeved at the bottom of the syringe body 3. The push rod 6 can slide within the syringe. An injection spring 7 is sleeved inside the push rod 6. A spring holder 10 penetrates through the injection spring 7. The spring holder 10 includes a spring guide rod structure 1011 provided in the middle of the spring holder 10 and spring arms provided on both sides of the spring holder 10. A catch 1012 is provided at the top of the spring arm. The spring guide rod structure 1011 passes through the inside of the injection spring 7, so that one end of the injection spring 7 abuts against the push rod 6 and the other end abuts against the spring holder 10. A guide sleeve 8 is sleeved outside the spring holder 10. A platform structure 81 is provided at the upper part of the guide sleeve 8. Before the injection pen is used, the platform structure 81 is engaged with the catch 1012. A guide groove 82 is also provided at the guide sleeve 8. A wing-shaped structure 61 corresponding to the guide groove 82 is provided at the push rod 6. A trigger sleeve 9 is sleeved outside the guide sleeve 8. The upper end of the trigger sleeve 9 abuts against the needle protection sleeve 22. A spring piece 91 is provided at the trigger sleeve 9 corresponding to the platform structure 81. A first protrusion 92 is provided on the inner wall of the spring piece 91 and abuts against the catch 1012. A rib 93 is provided at the trigger sleeve 9 corresponding to the wing-shaped structure 61. A return spring 11 is sleeved outside the trigger sleeve 9. During the use of the injection pen, the needle protection sleeve 22 pushes the trigger sleeve 9 downward. The spring piece 91 opens under the interaction of the first protrusion 92 and the catch 1012, causing the trigger sleeve 9 to move downward. The rib 93 pushes the wing-shaped structure 61, enabling the wing-shaped structure 61 to slide within the guide groove 82. The injection spring 7 pushes the push rod 6 for injection. At the same time, the spring holder 10 moves downward, and the injection is completed. Example 3:

[0058] As Figures 1-4 and Figures 12-13As shown, there is a gap between the syringe body 3 and the injection mechanism 5. An elastomer 15 is provided in the gap. A window 12 is sleeved outside the syringe body 3. The window 12 is installed in the housing 4. The window 12 axially limits the syringe body 3. The needle protection sleeve 2 has two notches 22. There is a circumferential step 23 in the notches 22. The window 12 is provided with a clamping seat 13. When the needle protection sleeve 2 moves relative to the housing 4 and continues to move from the first position, the step 23 of the needle protection sleeve 2 contacts the clamping seat 13. The needle protection sleeve 2 drives the window 12 to move together, so that the exposed distance of the needle 32 is maintained at a set distance. At this time, when continuing to move together, the elastomer 15 between the syringe body 3 and the injection mechanism 5 starts to be compressed until the injection mechanism 5 is triggered. Finally, the user presses to the maximum limit position. After the injection mechanism 5 is triggered, the needle protection sleeve and the syringe body 3 always move together, and the depth of the needle 32 piercing into the skin remains unchanged.

[0059] In order to ensure the triggering action of the injection mechanism 5, during the movement stroke of the needle protection sleeve 2, the total movement stroke of the needle protection sleeve 2 is greater than the stroke of the needle protection sleeve 2 driving the syringe body 3 together to the triggering position.

[0060] The needle protection sleeve 2 has a post-trigger stroke section, and the post-trigger stroke section includes: First-stage stroke: After the injection mechanism 5 is triggered, the needle protection sleeve 2 axially moves backward by a preset clearance amount ΔL along the axis direction. The ΔL is used to compensate for manufacturing tolerances and assembly errors; Second-stage stroke: Within the displacement range of ΔL, the needle protection sleeve 2 and the syringe body 3 move synchronously, and the axial distance between the two is constant to ensure that the depth of the injection needle 32 piercing into the skin remains unchanged.

[0061] During this process, since the needle protection sleeve 2 and the syringe body 3 always remain relatively stationary, the piercing depth no longer changes. In addition, during this process, slight back-and-forth shaking by the user will not change the piercing depth of the needle. Therefore, this can effectively improve the user's injection experience and reduce some pain. After the injection is completed, the forward displacement of the needle protection sleeve 2 covers the needle 32.

[0062] A piston 34 is provided in the syringe body 3. A push rod 6 is sleeved at the bottom of the syringe body 3. The push rod 6 can slide in the syringe. There is a gap between the piston 34 and the push rod 6 to ensure that before the needle protection sleeve 2 and the syringe body 3 move synchronously to trigger the injection mechanism 5, the push rod 6 does not contact the piston 34 and push the piston 34 to cause some liquid medicine to overflow.

[0063] As Figures 7-10As shown, the distance between the gaps between the syringe body 3 and the injection mechanism 5 is set between 0.5 - 5 mm, and the recommended value is 1.5 mm. The elastic force of the elastomer 15 in its initial state is greater than the force of the needle 32 piercing the skin, ensuring that the needle 32 can pierce into the skin before the elastomer 15 deforms. The injection mechanism 5 includes a push rod 6 sleeved at the bottom of the syringe body 3. The push rod 6 can slide within the syringe. An injection spring 7 is sleeved inside the push rod 6. A spring holder 10 passes through the injection spring 7. The spring holder 10 includes a spring guide rod structure 1011 disposed in the middle of the spring holder 10 and spring arms disposed on both sides of the spring holder 10. A catch 1012 is provided at the top of the spring arm. The spring guide rod structure 1011 passes through the interior of the injection spring 7, such that one end of the injection spring 7 abuts against the push rod 6 and the other end abuts against the spring holder 10. A guide sleeve 8 is sleeved outside the spring holder 10. A platform structure 81 is provided at the upper part of the guide sleeve 8. Before the injection pen is used, the platform structure 81 is engaged with the catch 1012. A guide groove 82 is also provided at the guide sleeve 8. A wing-shaped structure 61 corresponding to the guide groove 82 is provided at the push rod 6. A trigger sleeve 9 is sleeved outside the guide sleeve 8. The upper end of the trigger sleeve 9 abuts against the needle protection sleeve 22. A spring piece 91 is provided at the trigger sleeve 9 corresponding to the platform structure 81. A first protrusion 92 is provided on the inner wall of the spring piece 91 and abuts against the catch 1012. A rib 93 is provided at the trigger sleeve 9 corresponding to the wing-shaped structure 61. A return spring 11 is sleeved outside the trigger sleeve 9. During the use of the injection pen, when the needle protection sleeve 22 pushes the trigger sleeve 9 downward, the spring piece 91 opens under the interaction of the first protrusion 92 and the catch 1012, causing the trigger sleeve 9 to move downward. The rib 93 pushes the wing-shaped structure 61, enabling the wing-shaped structure 61 to slide within the guide groove 82. The injection spring 7 pushes the push rod 6 for injection. At the same time, the spring holder 10 moves downward, and the injection is completed. Example 4:

[0064] As Figures 1-4 and Figures 12-13As shown, there is a gap between the syringe body 3 and the injection mechanism 5. An elastomer 15 is provided in the gap. A window 12 is sleeved outside the syringe body 3. The window 12 is installed in the housing 4. The window 12 axially limits the syringe body 3. The needle protection sleeve 2 of the window 12 has two hollow structures 24. A clamping surface 25 is provided in the hollow structure 24. A clamping block 14 is provided on the outer side wall of the window 12. When the needle protection sleeve 2 moves relative to the housing 4 and continues to move from the first position, the clamping surface 25 of the needle protection sleeve 2 contacts the clamping block 14. The needle protection sleeve 2 drives the window 12 to move together, so that the exposed distance of the needle 32 is kept at a set distance. At this time, when continuing to move together, the elastomer 15 between the syringe body 3 and the injection mechanism 5 starts to be compressed until the injection mechanism 5 is triggered. Finally, the user presses to the maximum limit position. After the injection mechanism 5 is triggered, the needle protection sleeve and the syringe body 3 always move together, and the depth of the needle 32 piercing into the skin remains unchanged.

[0065] In order to ensure the triggering action of the injection mechanism 5, during the movement stroke of the needle protection sleeve 2, the total movement stroke of the needle protection sleeve 2 is greater than the stroke of the needle protection sleeve 2 driving the syringe body 3 to move together to the trigger position.

[0066] The needle protection sleeve 2 has a post-trigger stroke section, and the post-trigger stroke section includes: the first-stage stroke: after the injection mechanism 5 is triggered, the needle protection sleeve 2 axially moves backward by a preset clearance amount ΔL along the axis direction, and the ΔL is used to compensate for manufacturing tolerances and assembly errors; the second-stage stroke: within the displacement range of ΔL, the needle protection sleeve 2 and the syringe body 3 move synchronously, and the axial distance between the two is constant to ensure that the depth of the injection needle 32 piercing into the skin remains unchanged.

[0067] During this process, since the needle protection sleeve 2 and the syringe body 3 always remain relatively stationary, the insertion depth no longer changes. Additionally, during this process, slight back-and-forth shaking by the user will not change the insertion depth of the needle. Therefore, this can effectively improve the user's injection experience and reduce some pain. After the injection is completed, the forward displacement of the needle protection sleeve 2 covers the needle 32. The ways in which the window 12 axially limits the syringe body 3 include at least one of the following. One way is as follows: The front end of the syringe body 3 is equipped with a needle 32, a connection surface 33 is provided near the needle 32, and the rear end is a mounting seat 31 protruding from the syringe body 3. The upper part of the window 12 is provided with a claw 16, and the claw 16 is clamped with the clamping surface 25 of the syringe body 3, so that the clamping surface 25 of the syringe body 3 at the claw 16 is axially limited; Another way is as follows: The front end of the syringe body 3 is equipped with a needle 32, a connection surface 33 is provided near the needle 32, and the rear end is a mounting seat 31 protruding from the syringe body 3. The lower part of the window 12 is provided with a groove 26, and the groove 26 is clamped with the mounting seat 31, so that the groove 26 axially limits the mounting seat 31 of the syringe body 3.

[0068] The distance of the gap between the syringe body 3 and the injection mechanism 5 is set between 0.5 - 5 mm, and the recommended value is 1.5 mm. The initial state elastic force of the elastomer 15 is greater than the force of the needle 32 piercing the skin, ensuring that the needle 32 can pierce the skin before the elastomer 15 deforms.

[0069] A piston 34 is provided inside the syringe body 3, and a push rod 6 is sleeved at the bottom of the syringe body 3. The push rod 6 can slide inside the syringe. There is a gap between the piston 34 and the push rod 6, ensuring that before the needle protection sleeve 2 and the syringe body 3 move synchronously to trigger the injection mechanism 5, the push rod 6 does not contact the piston 34 and push the piston 34 to cause some liquid medicine to overflow.

[0070] Such as Figures 7-10As shown in the figure, an injection spring 7 is sleeved inside the push rod 6, and a spring frame 10 penetrates through the injection spring 7. The spring frame 10 includes a spring guide rod structure 1011 disposed in the middle of the spring frame 10 and spring arms disposed on both sides of the spring frame 10. A hook 1012 is provided at the top of the spring arm. The spring guide rod structure 1011 passes through the inside of the injection spring 7, so that one end of the injection spring 7 abuts against the push rod 6 and the other end abuts against the spring frame 10. A guide sleeve 8 is sleeved outside the spring frame 10. A platform structure 81 is provided at the upper part of the guide sleeve 8. Before the injection pen is used, the platform structure 81 is clamped with the hook 1012. A guide groove 82 is also provided at the guide sleeve 8, and a wing-shaped structure 61 corresponding to the guide groove 82 is provided at the push rod 6. A trigger sleeve 9 is sleeved outside the guide sleeve 8. The upper end of the trigger sleeve 9 abuts against the needle protection sleeve 22. A spring piece 91 is provided at the trigger sleeve 9 corresponding to the platform structure 81. A first protrusion 92 is provided on the inner wall of the spring piece 91 and abuts against the hook 1012. A rib 93 is provided at the trigger sleeve 9 corresponding to the wing-shaped structure 61. A return spring 11 is sleeved outside the trigger sleeve 9. During the use of the injection pen, the needle protection sleeve 22 pushes the trigger sleeve 9 downward. The spring piece 91 opens under the interaction of the first protrusion 92 and the hook 1012, causing the trigger sleeve 9 to move downward. The rib 93 pushes the wing-shaped structure 61 so that the wing-shaped structure 61 can slide in the guide groove 82. The injection spring 7 pushes the push rod 6 for injection. At the same time, the spring frame 10 moves downward, and the injection is completed.

[0071] Advantages of the present invention: The present invention provides an automatic injection pen with a floating needle, including a housing 4. The housing 4 is arranged along a longitudinal axis and has a proximal end and a distal end. The housing 4 is used to accommodate a syringe and a needle protection sleeve 2. The syringe includes a syringe body 3 and a needle 32 at the front end. The syringe body 3 is sleeved with the needle protection sleeve 2. The needle protection sleeve 2 can selectively axially displace relative to the housing 4 along the longitudinal axis. An injection mechanism 5 for triggering an injection action is provided at the needle protection sleeve 2 away from the proximal end. The injection mechanism 5 is located in the accommodation chamber of the housing 4. The syringe body 3 is movable along the axial direction of the housing 4. The needle protection sleeve 2 is movable along the axial direction of the housing 4. When the needle protection sleeve 2 moves relative to the housing 4 to a first position, the needle 32 is exposed relative to the needle protection sleeve. When the needle protection sleeve 2 continues to move relative to the housing 4 from the first position, the needle protection sleeve 2 moves synchronously with the syringe body 3, so that the exposed distance of the needle 32 is maintained at a set distance until the trigger action of the injection mechanism 5 is triggered.

[0072] The above-described embodiments merely represent several implementation manners of the present invention. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent for the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all fall within the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention shall be subject to the appended claims.

Claims

1. An automatic injection pen with floating needle, comprising a shell, the shell being arranged along a longitudinal axis and having a proximal end and a distal end, the shell being used to accommodate a syringe and a needle protection sleeve, the syringe comprising a syringe body and a needle at a front end, the syringe body being sleeved with the needle protection sleeve, the needle protection sleeve being selectively displaceable axially relative to the shell along the longitudinal axis, the needle protection sleeve being provided with an injection mechanism for triggering an injection action away from the proximal end, the injection mechanism being located in an accommodating chamber of the shell, characterized in that: The syringe body is movable along the axial direction of the shell; the needle protection sleeve is movable along the axial direction of the shell, and when the needle protection sleeve moves to a first position relative to the shell, the needle is exposed relative to the needle protection sleeve; when the needle protection sleeve continues to move relative to the shell from the first position, the needle protection sleeve moves synchronously with the syringe body, so that the exposed distance of the needle is maintained at a set distance until the triggering action of the injection mechanism is triggered.

2. The automatic injection pen with floating needle as claimed in claim 1, characterized in that: A piston is arranged in the syringe body, and a push rod is sleeved at the bottom of the syringe body. The push rod can slide in the syringe, and a gap is arranged between the piston and the push rod.

3. The automatic injection pen with floating needle as claimed in claim 1, characterized in that: The inner wall of the needle protection sleeve is provided with ribs, and a gap is provided between the syringe body and the injection mechanism. An elastic body is provided in the gap. During the injection process, the needle protection sleeve shifts backward, and the needle is relative to the needle protection sleeve to a preset distance. The ribs cooperate with the syringe body, and the needle protection sleeve moves synchronously with the needle. The elastic body between the syringe body and the injection mechanism is compressed until the injection mechanism is triggered.

4. The automatic injection pen with floating needle as claimed in claim 1, characterized in that: A gap is provided between the syringe body and the injection mechanism, an elastic body is provided at the gap, the needle protection sleeve has two notches, a circumferential step is provided in the notch, a needle is installed at the front end of the syringe body, and a mounting seat protruding from the syringe body is provided at the rear end, and the mounting seat is placed in the notch. When the step of the needle protection sleeve contacts the mounting seat, the needle protection sleeve moves with the syringe body so that the exposed distance of the needle is maintained at a set distance. At this time, the syringe body continues to move together, and the elastic body between the syringe body and the injection mechanism begins to compress until the injection mechanism is triggered.

5. The automatic injection pen with floating needle as claimed in claim 4, characterized in that: There is a matching point between the mounting seat and the rib, and the preset distance of the needle protruding from the needle protection sleeve is the length between the needle and the matching point minus the length between the skin contact surface of the needle protection sleeve and the matching point.

6. The automatic injection pen with floating needle as claimed in claim 1, characterized in that: The needle protection sleeve has a post-trigger stroke section, which includes: a first-stage stroke: after the injection mechanism is triggered, the needle protection sleeve is displaced backward along the axial direction by a preset gap amount ΔL, and the ΔL is used to compensate for manufacturing tolerances and assembly errors; a second-stage stroke: within the ΔL displacement range, the needle protection sleeve and the syringe body maintain synchronous movement, and the axial spacing between the two is constant to ensure that the depth of the injection needle penetrating the skin remains unchanged.

7. The automatic injection pen with floating needle as claimed in claim 1, characterized in that: A gap is provided between the syringe body and the injection mechanism, an elastic body is provided at the gap, a window is connected to the outer shell of the syringe body, the window is installed in the outer shell, the window limits the syringe body in the axial direction, the needle protection sleeve has two notches, the notches have circumferential steps, the window is provided with a retaining seat, when the steps of the needle protection sleeve contact the retaining seat, the needle protection sleeve moves with the window, so that the exposed distance of the needle is maintained at the set distance, and the movement continues at this time, and the elastic body between the syringe body and the injection mechanism begins to compress until the injection mechanism is triggered.

8. The automatic injection pen with floating needle as claimed in claim 1, characterized in that: A gap is provided between the syringe body and the injection mechanism, an elastic body is provided at the gap, a window is provided on the outer shell of the syringe body, the window is installed in the outer shell, the window limits the syringe body in the axial direction, the window and the needle protection sleeve have two hollow structures, the hollow structure has a clamping surface, and the outer wall of the window is provided with a clamping block. When the clamping surface of the needle protection sleeve contacts the clamping block, the needle protection sleeve moves with the window, so that the exposed distance of the needle is maintained at the set distance. At this time, they continue to move together, and the elastic body between the syringe body and the injection mechanism begins to compress until the injection mechanism is triggered.

9. The automatic injection pen with floating needle as claimed in claim 7, characterized in that: The manner in which the window limits the syringe body in the axial direction includes at least one of the following manners, wherein one manner is: a needle is installed at the front end of the syringe body, a connecting surface is provided near the needle, and a mounting seat protruding from the syringe body is provided at the rear end, and a claw is provided at the upper part of the window, and the claw is engaged with the engaging surface of the syringe body so that the claw limits the engaging surface of the syringe body in the axial direction; another manner is: a needle is installed at the front end of the syringe body, a connecting surface is provided near the needle, and a mounting seat protruding from the syringe body is provided at the rear end, and a groove is provided at the lower part of the window, and the groove is engaged with the mounting seat so that the groove limits the mounting seat of the syringe body in the axial direction.

10. The automatic injection pen with floating needle as claimed in claim 1, characterized in that: The distance of the gap between the syringe body and the injection mechanism is set between 0.5-5 mm.

11. The automatic injection pen with floating needle as claimed in claim 3, characterized in that: The elastic force of the elastic body in the initial state is greater than the force of the needle piercing the skin, ensuring that the needle can pierce the skin before the elastic body is deformed.

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