A helix-activated pre-filled auto-injector

Abstract

A pre-filled automatic injection pen, comprising a trigger assembly, the trigger assembly comprising a support frame fixed in a housing for initially defining the initial position of a push rod, a spring catch, a protective sleeve; the push rod is installed in the support frame and initially positioned by the support frame, and after the protective sleeve is triggered, the push rod is driven by the trigger spring to move the pre-filled syringe to complete the automatic needle insertion; the protective sleeve is installed outside the support frame, and initially buckled outside the support frame and can be moved after being driven by the trigger sleeve to trigger the push rod, and can limit the backward movement of the trigger sleeve after moving to protect the needle; the trigger spring is installed inside the push rod through the spring catch, and is used to provide the push rod with the ejection force after triggering, and provide the spring catch with the ejection force after the push rod is separated from the spring catch; the spring catch is installed between the support frame and the push rod, and after the injection is completed, the spring catch is ejected to hit the back cover to make a sound under the driving of the trigger spring; the back cover is fixed at the rear end of the support frame, and is used to hit the spring catch to make a sound.

Description

Technical Field

[0001] This invention belongs to the field of automatic injection technology, specifically relating to a spiral-excited pre-filled automatic injection pen. Background Technology

[0002] The pre-filled automatic injection pens currently on the market have the following drawbacks:

[0003] 1. Currently, to achieve automatic injection, these products use electric motors or similar devices as the power source for the injection mechanism. This method consumes energy, has high operating costs, a complex control system, and the use of batteries causes environmental pollution. Furthermore, connecting to various transmission mechanisms results in a large overall product size, failing to meet the requirements of portability and ease of use.

[0004] 2. Currently, most related products on the market rely on electronic components to achieve multi-dimensional feedback, including visual and auditory feedback, and still require battery power. If the product is used in an environment with strong electromagnetic interference, it cannot perform its intended function. Electronic components are easily affected by the environment, age rapidly, and are not suitable for long-term storage. In complex environments, it is difficult to guarantee the stability and reliability of the entire device.

[0005] 3. Currently, such products on the market have many operating steps, often requiring at least three steps. Patients still face the risk of forgetting the steps when using them periodically, resulting in poor patient compliance.

[0006] 4. Currently, after use, products on the market often require users to insert a limit pin or rotate the locking mechanism to achieve self-locking, thereby preventing secondary use and accidental triggering. However, in certain situations, the limit pin may be lost, or the patient may forget to operate it, rendering the product unable to guarantee self-locking after use. Furthermore, this design violates ergonomics and does not conform to the design characteristics of this type of product.

[0007] 5. In order to achieve the automatic injection function, most existing products adopt a snap-fit ​​structure design on the trigger mechanism, which uses the elastic deformation of the parts to complete the triggering and locking processes. This design often requires the snap-fit ​​structure to be in a state of pressure deformation. Since this type of product is for single use, the parts are usually injection molded from polymer materials. The snap-fit ​​structure of the parts is not conducive to transportation and long-term storage under pressure, and is greatly affected by the environment. Such structures are prone to plastic deformation. Summary of the Invention

[0008] In view of the problems existing in the above background technology introduction, the purpose of the present invention is to provide a pre-filled automatic injection pen with reliable excitation, reliable injection completion reminder function, and needle protection.

[0009] The technical solution adopted in this invention is:

[0010] A spiral-excited pre-filled automated injection pen, comprising

[0011] The outer shell is a hollow structure;

[0012] The protective cap is fastened to the head of the outer shell and can pull off the internal protective rubber sleeve of the pre-filled syringe when it is pulled off.

[0013] An excitation sleeve is movably installed inside the housing and is provided with a return spring for resetting along the axial direction between it and the housing. The head of the excitation sleeve protrudes outside the housing and can trigger the spiral excitation assembly when it moves from the initial position to the limit position.

[0014] The pre-filled syringe is clamped on the PFS seat during pre-loading. During the process of the trigger sleeve moving from the initial position to the limit position, the injection end of the pre-filled syringe is always hidden inside the needle sheath. When the injection end of the pre-filled syringe is triggered, it instantly displaces and extends out of the trigger sleeve to achieve automatic needle insertion.

[0015] The PFS seat is fixedly installed between the excitation sleeve and the pre-filled syringe, and initially defines the initial position of the pre-filled syringe and provides support when the pre-filled syringe automatically inserts the needle;

[0016] A helical excitation assembly is installed inside the housing, the helical excitation assembly including...

[0017] The cavity, which is fixed to the outer shell, is used to convert the rotational motion of the threaded push rod into axial forward movement;

[0018] A nut, which is rotatable relative to the cavity, is installed in the cavity, and a torsion spring that drives the nut to rotate is provided between the nut and the cavity.

[0019] The threaded push rod is threaded into the nut and is driven forward by the rotation of the nut, and then drives the pre-filled syringe to move to complete the automatic needle insertion.

[0020] The clutch is fitted outside the nut and can move from the engaged position to the activated position under the drive of the activation sleeve. When it is in the engaged position, it engages with the nut to stop the nut. When it is in the activated position, the nut can rotate.

[0021] End cap, which is fitted and detachably attached to the rear end of the nut;

[0022] A clutch spring, installed between the clutch component and the end cap, drives the clutch component from the activation position to the limiting position after injection, restricting the backward movement of the activation sleeve for needle protection, and causing the clutch component to collide with the nut to produce a sound. The spiral activation assembly of this invention, after activation, drives the threaded push rod forward through the rotation of the nut, thereby moving the pre-filled syringe to complete automatic needle insertion, which is more reliable than a spring-driven push rod. Simultaneously, the clutch component achieves both activation and needle protection. Compared to elastic deformation for triggering and locking processes, activation and needle protection are more reliable. Furthermore, the clutch component works in conjunction with the nut to produce the injection sound, resulting in a simpler and more rational structure with smoother operation.

[0023] Furthermore, the clutch is a hollow cylindrical structure with symmetrically protruding lugs on its surface that cooperate with the excitation sleeve to drive or limit it.

[0024] Furthermore, a first groove for the lug to move from the engagement position to the excitation position and a second groove for the lug to move from the excitation position to the limiting position are formed between the front end face of the end cap and the rear end face of the cavity. The first groove and the second groove are connected, and the lug protrudes from the first groove and the second groove. In this invention, the lug remains in contact with the excitation sleeve throughout the process of moving from the engagement position to the excitation position.

[0025] Furthermore, a right-angled trapezoidal groove, wider on the outer side and narrower on the inner side, is symmetrically formed on the front end face of the end cap, and a symmetrically formed oblique W-shaped groove is formed on the rear end face of the cavity. The opening width of the right-angled trapezoidal groove is smaller than the opening width of the oblique W-shaped groove, and the oblique directions of the right-angled trapezoidal groove and the oblique W-shaped groove are consistent. A first sliding groove and a second sliding groove are formed between the right-angled trapezoidal groove and the oblique W-shaped groove. Because the opening width of the right-angled trapezoidal groove is smaller than the opening width of the oblique W-shaped groove, when the lug moves from the excitation position along the second sliding groove to the limiting position, the lug is limited at the limiting position, thereby restricting the backward movement of the excitation sleeve.

[0026] Furthermore, both the front end face of the clutch and the middle end face of the nut are provided with meshing teeth. When in the meshing position, the meshing teeth on the clutch engage with the meshing teeth on the nut to stop the movement. When entering the limited position, the meshing teeth on the clutch and the meshing teeth on the nut can collide and produce a sound.

[0027] Furthermore, the nut includes a hollow cylindrical nut body, the interior of which is provided with an internal thread that engages with a threaded push rod for threaded drive, and a front-facing cover is provided around the middle of the nut body, forming a cavity between the cover and the nut body to accommodate a torsion spring, and the meshing teeth on the nut are provided on the rear end face of the cover.

[0028] Furthermore, the surface of the cover is provided with a raised rib, and the cavity is provided with a groove relative to the position of the raised rib, with the raised rib located in the groove and an axially limiting nut.

[0029] Furthermore, an L-shaped positioning groove is provided at the rear end of the nut body, and a positioning component that can be detachably connected to the positioning groove is provided inside the end cap.

[0030] Furthermore, the front end face of the cavity is in a flat fit with the threaded push rod, thereby restricting the rotation of the threaded push rod and allowing it to move only axially.

[0031] Furthermore, the excitation sleeve includes a sleeve body that protects the needle tip. The sleeve body is provided with symmetrical extension arms. The tail end of the extension arm is provided with an excitation part that cooperates with the lug for excitation and a limiting part that cooperates with the lug for limitation.

[0032] Compared with the prior art, the significant advantages of this invention include:

[0033] 1. After activation, the spiral excitation assembly drives the threaded push rod forward by rotating the nut, which in turn drives the pre-filled syringe to move and complete the automatic needle insertion. This is more reliable than the spring-driven push rod.

[0034] 2. The combination of a clutch component to achieve excitation and needle protection is more reliable than the elastic deformation process for triggering and locking. In addition, the clutch component works with the nut to produce sound during injection, making the structure simpler, more reasonable, and smoother. Attached Figure Description

[0035] Figure 1 This is an exploded structural diagram of the present invention;

[0036] Figure 2 This is a schematic diagram of the external structure of the present invention;

[0037] Figure 3 This is a schematic diagram of the structure of the excitation sleeve of the present invention;

[0038] Figure 4 This is a schematic diagram of the cavity structure of the present invention;

[0039] Figure 5 This is a schematic diagram of the nut structure of the present invention;

[0040] Figure 6 This is a schematic diagram of the clutch component of the present invention;

[0041] Figure 7 This is a schematic diagram of the end cap structure of the present invention;

[0042] Figure 8 This is a cross-sectional view of the clutch component of the present invention when it is in the engaged position;

[0043] Figure 9 This is a cross-sectional view of the clutch component of the present invention when it is in the activation position;

[0044] Figure 10 This is a cross-sectional view of the clutch component of the present invention when it is in the limited position;

[0045] Figure 11 This is a schematic diagram of the initial state of the invention and its engagement with the excitation sleeve;

[0046] Figure 12 This is a schematic diagram of the structure for needle protection after excitation according to the present invention.

[0047] Among them, 1. Protective cap, 1a. Protective cap buckle, 2. Outer shell, 21. Viewing window, 3. Excitation sleeve, 31. Sleeve body, 32. Extension arm, 33. Excitation part, 34. Limiting part, 35. Slot, 36. Protective buckle, 4. Pre-filled syringe, 41. Inner protective rubber sleeve, 42. Protruding tail end, 5. Threaded push rod, 6. Cavity, 61. Slanted W-shaped groove, 62. Groove, 7. Torsion spring, 8. Clutch spring, 9. Nut. 91. Nut body; 92. Cover; 93. Cavity; 94. Rib; 95. Positioning groove; 10. Clutch; 101. Lug; A. Engagement position; B. Actuation position; C. Limiting position; 11. End cap; 111. Right-angled trapezoidal groove; 112. Positioning element; 12. PFS seat; 121. Cantilever; 122. External snap; 123. Internal snap; 124. Stepped surface; 13. Engaging teeth; 14. First slide groove; 15. Second slide groove. Detailed Implementation

[0048] The present invention will be further described below with reference to specific embodiments, but the invention is not limited to these specific embodiments. Those skilled in the art should recognize that the present invention covers all alternatives, improvements, and equivalents that may be included within the scope of the claims.

[0049] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "clockwise," and "counterclockwise," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more, unless otherwise expressly defined.

[0050] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0051] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0052] See Figure 1-12 This embodiment provides a spiral-excited pre-filled automatic injection pen, including a cap 1, a shell 2, an excitation sleeve 3, a pre-filled syringe 4, a threaded push rod 5, a cavity 6, a torsion spring 7, a clutch spring 9, a nut 10, a clutch component 10, an end cap 11, and a PFS seat 12. The threaded push rod 5, the cavity 6, the torsion spring 7, the clutch spring 9, the nut 10, the clutch component 10, and the end cap 11 constitute a spiral excitation assembly, which is installed inside the shell 2.

[0053] In this embodiment, the protective cap 1 is fastened to the head of the outer shell 2 and, when removed, can cause the internal protective rubber sleeve 41 of the pre-filled syringe 4 to detach together. Specifically, the protective cap 1 is provided with symmetrically arranged protective cap buckles 1a, which initially engage with the internal protective rubber sleeve 41 of the pre-filled syringe 4. When the protective cap 1 is removed, the internal protective rubber sleeve 41 of the pre-filled syringe 4 disengages from the pre-filled syringe 4, exposing the needle.

[0054] The outer shell 2 described in this embodiment is a hollow structure; the outer shell 2 is provided with a viewing window 21 for checking the liquid condition, whether the pre-filled syringe is in the correct position, and for checking the infusion status after registration.

[0055] The excitation sleeve 3 described in this embodiment is movably installed inside the housing 2 and has a return spring for resetting along the axial direction between it and the housing 2. The head of the excitation sleeve 3 protrudes outside the housing 2, and when it moves from the initial position to the limit position, it can activate the spiral excitation assembly. Specifically, the excitation sleeve 3 includes a sleeve body 31 for protecting the needle tip. The sleeve body 31 has symmetrical extension arms 32. The tail end of the extension arm 32 is provided with an excitation part 33 that cooperates with the lug 101 on the clutch 10 for excitation, and a limiting part 34 that cooperates with and limits the lug 101 for limiting. The extension arm 32 has a slot 35 for the movement of the cantilever 121 of the PFS seat 12. The inner side of the extension arm 32 has a protective buckle 36 that radially protrudes from one end of the slot 35 and limits the initial position of the cantilever 121 of the PFS seat 12.

[0056] In this embodiment, the pre-filled syringe 4 is clamped on the PFS seat 12 during pre-loading. During the process of the excitation sleeve 3 moving from the initial position to the limit position, the injection end of the pre-filled syringe 4 is always hidden inside the needle sheath. When the injection end of the pre-filled syringe 4 is triggered, it instantly shifts and extends out of the excitation sleeve 3 to achieve automatic needle insertion. Specifically, the pre-filled syringe 4 is pre-loaded and held in position on the cantilever 121 of the PFS seat 12. This position is the initial position of the pre-filled syringe 4. During activation, the activation sleeve 3 moves from the initial position to the limit position. When the activation sleeve 3 is in the limit position, the injection end of the pre-filled syringe 4 is hidden inside the activation sleeve 3. When the injection end of the pre-filled syringe 4 is triggered, it instantly shifts from the initial position to the stepped surface 124 on the PFS seat 12, exceeding the activation sleeve 3 to achieve automatic needle insertion. The injection end is a needle structure and is initially provided with an internal protective rubber sleeve 41 to protect the injection end. The pre-filled syringe 4 is pre-filled with liquid and sealed by a rubber stopper. The protruding tail end 42 of the pre-filled syringe 4 is protruding and can be limited to the initial position by the PFS seat 12, and cooperates with the stepped surface 124 on the PFS seat 12 to limit the movement distance.

[0057] The threaded push rod 5 described in this embodiment is threadedly connected to the nut 9 and driven by the rotation of the nut 9 to move forward and then drive the pre-filled syringe 4 to move to complete the automatic needle insertion; the threaded push rod 5 has a flat structure and external threads are provided on its arc surface, which cooperate with the internal threads in the nut 9 to rotate.

[0058] The cavity 6 described in this embodiment is a hollow structure, fixed to the outer shell 2, used to convert the rotational movement of the threaded push rod 5 into axial forward movement. Specifically, the front end face of the cavity 6 and the threaded push rod 5 have a flat fit, that is, the through hole at the front end of the cavity 6 is a flat hole, thereby restricting the rotation of the threaded push rod 5 and allowing only axial movement. A groove 62 is circumferentially formed within the cavity 6 relative to the position of the protrusion 94 of the nut 9. The protrusion 94 is located within the groove 62, axially limiting the nut 9, so that the nut 9 can only rotate relative to the cavity 6.

[0059] The clutch spring 8 described in this embodiment is installed between the clutch component 10 and the end cap 11. After the injection is completed, it drives the clutch component 10 from the excitation position B to the limiting position C to restrict the excitation sleeve 3 to move backward for needle protection, and causes the clutch component 10 to collide with the nut 9 to produce a sound.

[0060] The nut 9 described in this embodiment is rotatably mounted within the cavity 6, and a torsion spring 7 is provided between the nut 9 and the cavity 6 to drive the rotation of the nut 9. The nut 9 in this embodiment includes a hollow cylindrical nut body 91, and the interior of the nut body 91 is provided with an internal thread that engages with the threaded push rod 5 for threaded drive. A cover 92 with an opening facing forward is provided around the middle of the nut body 91, and a cavity 93 for accommodating the torsion spring 7 is formed between the cover 92 and the nut body 91. The meshing teeth 13 on the nut 9 are provided on the rear end face of the cover 92. The surface of the cover 92 is provided with a raised rib 94, which is located in the groove 62 and axially limits the nut 9, so that the nut 9 can only rotate relative to the cavity 6. An L-shaped positioning groove 95 is provided at the rear end of the nut body 91 for connecting and fixing the end cap 11. After activation, the present invention drives the threaded push rod 5 to move forward by rotating the nut 9 to drive the pre-filled syringe to complete the automatic needle insertion, which is more reliable than the spring-driven push rod.

[0061] The clutch 10 described in this embodiment is fitted over the nut 9 and can move from engagement position A to activation position B under the drive of the activation sleeve 3. In engagement position A, it engages with the nut 9 to stop it; in activation position B, the nut 9 can rotate. Specifically, the clutch 10 is a hollow cylindrical structure with symmetrically protruding lugs 101 on its surface that cooperate with or limit the activation sleeve 3. Both the front end face of the clutch 10 and the middle end face of the nut 9 are provided with engagement teeth 13. In engagement position A, the engagement teeth 13 on the clutch 10 engage with the engagement teeth 13 on the nut 9 to stop it. When entering the limiting position C, the engagement teeth 13 on the clutch 10 and the engagement teeth 13 on the nut 9 collide and produce sound. The engagement teeth 13 on the nut 9 are continuously arranged, while the engagement teeth 13 on the clutch 10 are spaced apart. At the same time, the clutch 10 is used to realize the excitation and needle protection. Compared with the elastic deformation to complete the triggering and locking processes, the excitation and needle protection are more reliable. Moreover, the clutch 10 is also used in conjunction with the nut 9 to inject sound. The structure is simpler and more reasonable, and the cooperation is smoother.

[0062] In this embodiment, the end cap 11 is fitted and detachably connected to the rear end of the nut 9. The end cap 11 has a protruding positioning element 112 that detachably connects to the positioning groove 95. A first sliding groove 14 for the lug 101 to move from the engagement position A to the excitation position B and a second sliding groove 15 for the lug 101 to move from the excitation position B to the limiting position C are formed between the front end face of the end cap 11 and the rear end face of the cavity 6. The first sliding groove 14 and the second sliding groove 15 communicate with each other, and the lug 101 protrudes from both the first and second sliding grooves 14 and 15. In this invention, the lug 101 remains in contact with the excitation sleeve 3 throughout the movement from the engagement position A to the excitation position B. Specifically, a right-angled trapezoidal groove 111, wider on the outer side and narrower on the inner side, is symmetrically formed on the front end face of the end cap 11. A symmetrically formed oblique W-shaped groove 61 is formed on the rear end face of the cavity 6. The opening width of the right-angled trapezoidal groove 111 is smaller than the opening width of the oblique W-shaped groove 61. The oblique direction of the right-angled trapezoidal groove 111 and the oblique W-shaped groove 61 is consistent. A first sliding groove 14 and a second sliding groove 15 are formed between the right-angled trapezoidal groove 111 and the oblique W-shaped groove 61. Because the opening width of the right-angled trapezoidal groove 111 is smaller than the opening width of the oblique W-shaped groove 61, when the lug 101 moves from the excitation position B along the second sliding groove 15 to the limiting position C, the lug 101 is limited at the limiting position C, thereby restricting the rearward movement of the excitation sleeve 3. The first sliding groove 14 and the second sliding groove 15 are formed by the cooperation between the end cap 11 and the cavity 6, which facilitates the loading and unloading of the clutch 10. Of course, the first slide groove 14 and the second slide groove 15 can be directly set on one of the components.

[0063] The PFS seat 12 described in this embodiment is fixedly installed between the excitation sleeve 3 and the pre-filled syringe 4, and initially defines the initial position of the pre-filled syringe 4 and provides support when the pre-filled syringe 4 automatically inserts its needle. The PFS seat 12 is symmetrically provided with cantilever 121, which is provided corresponding to the slot 35 of the excitation sleeve 3. The outer side of the end of the cantilever 121 is provided with an outer buckle 122 that initially cooperates with the protective buckle 36 of the excitation sleeve 3 to define the position of the cantilever 121. The inner side of the end of the cantilever 121 is provided with an inner buckle 123 that initially cooperates with the protruding tail end 42 of the pre-filled syringe 4 to support the pre-filled syringe 4. The inner wall of the PFS seat 12 is provided with a stepped surface 124 that restricts the movement of the pre-filled syringe 4. The inner wall of the PFS seat 12 is provided with upright ribs along the axial direction from the stepped surface 124 to its tail end to provide support for the pre-filled syringe 4 when it automatically inserts its needle. After the outer buckle 122 of the cantilever 121 of the PFS seat 12 disengages from the protective buckle 36, the cantilever 121 can deform within the slot 35, thereby allowing the pre-filled syringe 4 to move down to the stepped surface 124 under the action of the threaded push rod 5, opening the inner buckle 123. A silicone gasket can be provided on the stepped surface 124 to protect the protruding tail end 42 of the pre-filled syringe 4 and prevent it from breaking during movement.

[0064] When installing the spiral excitation assembly of the present invention, the threaded push rod 5 is installed on the nut 9 to form a nut assembly, the nut assembly and the torsion spring 7 are installed in the cavity 6, and the circumferential connection is achieved by the protruding rib 94 and the groove 62; the clutch 10 and the clutch spring 8 are sequentially fitted on the outside of the nut 9, and finally the end cap 11 is fixed on the rear end of the nut 9.

[0065] When installing the pre-filled automatic injection pen, the return spring is inserted into the excitation sleeve 3, and then the excitation sleeve 3 is inserted into the outer shell 2. Next, the protective cap 1 is inserted into the outer shell 2 and placed over the excitation sleeve 3. Then, the PFS seat 12 is inserted into the outer shell 2 and positioned to cooperate with the excitation sleeve 3. At this time, the cantilever 121 on the PFS seat 12 is located in the slot 35 of the excitation sleeve 3, and the outer buckle 122 cooperates with the protective buckle 36 for initial positioning. The pre-filled syringe 4 is then inserted into the PFS seat 12, and the inner buckle 123 cooperates with the protruding tail end 42 for limiting. Finally, the assembled spiral excitation assembly is inserted into the outer shell 2 and fixedly installed by fastening the cavity 6 to the outer shell 2.

[0066] Initially, the clutch 10 engages with the nut 9, preventing the threaded screw 7 from being pushed. When using the invention, the protective cap 1 is removed to detach the internal protective rubber sleeve 41 from the pre-filled syringe 4. The activation sleeve 3 is pressed down, causing it to move backward. When the activation part 33 of the activation sleeve 3 contacts the lug 101 of the clutch 10, it drives the lug 101 from engagement position A to activation position B, thereby disengaging the clutch 10. At this time, the nut 9 rotates under the drive of the torsion spring 7, causing the threaded push rod 5 to rotate. Under the constraint of the cavity 6, the threaded push rod 5's rotation transforms into axial forward movement, thus activating the pre-filled syringe of the pre-filled automatic injection pen to move and automatically insert the needle. After the injection is completed, the excitation sleeve 3 springs back, and its excitation part 33 leaves the lug 101. Under the action of the clutch spring 8, the lug 101 moves from the excitation position B to the limiting position C. At this time, the lug 101 contacts the limiting part 34 of the excitation sleeve 3, thereby preventing the excitation sleeve 3 from moving axially backward again, thus realizing needle protection, and causing the meshing teeth 13 of the clutch 10 to collide with the meshing teeth 13 of the nut 9 to make a sound.

[0067] This invention uses the rotation of nut 9 after activation to drive the threaded push rod 5 forward, thereby moving the pre-filled syringe to complete automatic needle insertion. This is more reliable than the spring-driven push rod. The clutch 10 is used to achieve activation and needle protection. Compared to elastic deformation for triggering and locking, this method is more reliable in both activation and needle protection. Furthermore, the clutch 10 works in conjunction with nut 9 to produce the injection sound, resulting in a simpler and more reasonable structure with smoother operation.

Claims

1. A spiral-activated pre-filled automatic injection pen, comprising: The outer shell (2) is a hollow structure; The protective cap (1) is fastened to the head of the outer shell (2) and can pull off the internal protective rubber sleeve (41) of the pre-filled syringe (4) when it is pulled off; The excitation sleeve (3) is movably installed inside the housing (2) and is provided with a return spring for resetting between it and the housing (2) along the axial direction. The head of the excitation sleeve (3) is exposed outside the housing (2). When it moves from the initial position to the limit position, it can trigger the spiral excitation assembly. The pre-filled syringe (4) is clamped on the PFS seat (12) during pre-loading. During the process of the excitation sleeve (3) moving from the initial position to the limit position, the injection end of the pre-filled syringe (4) is always hidden inside the needle sheath. When the injection end of the pre-filled syringe (4) is triggered, it is instantly displaced and extends out of the excitation sleeve (3) to achieve automatic needle insertion. The PFS seat (12) is fixedly installed between the excitation sleeve (3) and the pre-filled syringe (4), and initially defines the initial position of the pre-filled syringe (4) and provides support when the pre-filled syringe (4) automatically inserts its needle; Its features are: A spiral excitation assembly is installed inside the outer casing (2), the spiral excitation assembly including The cavity (6), which is fixed on the outer shell (2), is used to convert the rotational motion of the threaded push rod (5) into axial forward movement; Nut (9), which is rotatable relative to cavity (6), is installed in cavity (6), and a torsion spring (7) is provided between it and cavity (6) to drive nut (9) to rotate. The threaded push rod (5) is threadedly connected to the nut (9) and driven by the rotation of the nut (9) to move forward and then drive the pre-filled syringe (4) to move to complete the automatic needle insertion; The clutch (10) is fitted outside the nut (9) and can move from the engagement position (A) to the activation position (B) under the drive of the activation sleeve (3). When it is in the engagement position (A), it engages with the nut (9) to stop the nut (9). When it is in the activation position (B), the nut (9) can rotate. The clutch (10) is a hollow cylindrical structure with symmetrically protruding lugs (101) on its surface that cooperate with the activation sleeve (3) for driving or limiting. An end cap (11) is fitted and detachably connected to the rear end of a nut (9); a first groove (14) for the lug (101) to move from the engagement position (A) to the activation position (B) and a second groove (15) for the lug to move from the activation position (B) to the limiting position (C) are formed between the front end face of the end cap (11) and the rear end face of the cavity (6); the first groove (14) and the second groove (15) communicate with each other; the lug (101) protrudes from the first groove (14) and the second groove (15); the end cap (11) is fitted and detachably connected to the rear end of a nut (9); the front end face of the end cap (11) and the rear end face of the cavity (6) form a first groove (14) for the lug (101) to move from the engagement position (A) to the activation position (B) and a second groove (15) for the lug to move from the activation position (B) to the limiting position (C); the first groove (14) and the second groove (15) are connected; the lug (101) is provided to protrude from the first groove (14) and the second groove (15); the end cap (11) is fitted and detachably connected to the rear end of a nut (9); the front end face of the end cap (11) and the rear end face of the cavity (6) form a first groove (14) for the lug (101) to move from the engagement position (A) to the activation position (B) and a second groove (15) for the lug (101) to move from the activation position (B) to the limiting position (C); the end cap (11) is fitted and detachably connected to the rear end of a nut (9) and a second groove (15) for the lug (101) to move from the engagement position (A) to the activation position (B) and a second groove (15) for the lug (101) to move from the activation position ( A right-angled trapezoidal groove (111) with a wider outer side and a narrower inner side is symmetrically opened on the front end face of the cavity (6). A slanted W-shaped groove (61) is symmetrically opened on the rear end face of the cavity (6). The width of the opening end of the right-angled trapezoidal groove (111) is smaller than the width of the opening end of the slanted W-shaped groove (61). The slant direction of the right-angled trapezoidal groove (111) and the slanted W-shaped groove (61) are consistent. A first sliding groove (14) and a second sliding groove (15) are formed between the right-angled trapezoidal groove (111) and the slanted W-shaped groove (61). The clutch spring (8) is installed between the clutch (10) and the end cap (11) to drive the clutch (10) from the excitation position (B) to the limiting position (C) after the injection is completed, thereby limiting the excitation sleeve (3) to move backward for needle protection and causing the clutch (10) to collide with the nut (9) to make a sound. The excitation sleeve (3) includes a sleeve body (31) for protecting the needle tip. The sleeve body (31) is provided with symmetrical extension arms (32). The tail end of the extension arm (32) is provided with an excitation part (33) that cooperates with the lug (101) for excitation and a limiting part (34) that cooperates with the lug (101) for limiting.

2. The spiral-excited pre-filled automatic injection pen according to claim 1, characterized in that: Both the front end face of the clutch (10) and the middle end face of the nut (9) are provided with meshing teeth (13). When in the meshing position (A), the meshing teeth (13) on the clutch (10) and the meshing teeth (13) on the nut (9) mesh and stop. When entering the limiting position (C), the meshing teeth (13) on the clutch (10) and the meshing teeth (13) on the nut (9) can collide and make a sound.

3. The spiral-excited pre-filled automatic injection pen according to claim 1, characterized in that: The nut (9) includes a hollow cylindrical nut body (91). The nut body (91) has an internal thread that engages with the threaded push rod (5) for threaded drive. The nut body (91) has a cover (92) with an opening facing forward in the middle. A cavity (93) for accommodating a torsion spring is formed between the cover (92) and the nut body (91). The meshing teeth (13) on the nut (9) are located on the rear end face of the cover (92).

4. The spiral-excited pre-filled automatic injection pen according to claim 3, characterized in that: The surface of the cover (92) is provided with a raised rib (94), and the cavity (6) is provided with a groove (62) relative to the position of the raised rib (94). The raised rib (94) is located in the groove (62) and axially limiting nut (9).

5. The spiral-excited pre-filled automatic injection pen according to claim 3, characterized in that: The rear end of the nut body (91) is provided with an L-shaped positioning groove (95), and the end cap (11) is provided with a positioning element (112) that is detachably connected to the positioning groove (95).

6. The spiral-excited pre-filled automatic injection pen according to claim 1, characterized in that: The front end face of the cavity (6) and the threaded push rod (5) are in a flat fit.

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