Automatic injection pen

Abstract

The invention relates to an automatic injection pen. Comprising a housing; a screw rod; a dose setting knob; a dose indicating ring; a screw sleeve; when the dose is set, the dose indication ring support frame is in rotary linkage with the dose indication ring and the screw rod sleeve; an elastic arm is arranged in the circumferential direction of the far end of the dose indicating ring supporting frame, at least one first outer protruding tooth is arranged on the elastic arm, and a first inner gear ring meshed with the first outer protruding tooth is arranged on the inner wall of the far end of the shell. The outer wall of the screw sleeve is provided with a clamping jaw which penetrates out of the dose indicating ring supporting frame and can clamp the elastic arm. A torsion spring; when the injection button is subjected to axial force towards the far end, the screw sleeve is driven to move towards the far end, the clamping jaw radially extrudes the elastic arm to contract inwards, so that the first outer convex teeth are disengaged from the meshing state, the torsion of the torsion spring is released, the dose indication ring supporting frame is pushed to rotate, the screw sleeve is driven to rotate, and then the screw is driven to do spiral motion for injection. According to the technical scheme, the dose setting process is more stable.

Description

Technical Field

[0001] The present application relates to the field of medical devices, and in particular to an automatic injection pen. Background Art

[0002] The syringe is a common medical device. The principle behind the syringe was discovered as early as the 15th century. It primarily uses a needle to extract or inject gases or liquids. Syringes can also be used in medical devices and as containers for injectable solutions, such as those used in some scientific instruments for chromatography, where injections are made through a rubber septum. A syringe consists of a barrel with a small hole at the front and a matching piston rod. It is used to inject or withdraw small amounts of liquids or other substances into or from otherwise inaccessible areas. When the piston rod is withdrawn, the liquid or gas is drawn in through the small hole at the front of the barrel, and when the piston rod is pushed in, the liquid or gas is expelled.

[0003] Diabetics require subcutaneous injections of artificial insulin. To prevent contamination, artificial insulin is packaged in a special vial with a piston at one end. During injection, a syringe pushes the piston at one end of the vial, squeezing the liquid medicine out the other end and into the body through a needle. Because different diabetic patients require different injection doses, the syringe must be equipped with a structure that precisely defines the dose. However, existing syringes with precisely defined doses suffer from complex structures and high manufacturing costs. Summary of the Invention

[0004] In view of this, an embodiment of the present application provides an automatic injection pen to solve at least one problem existing in the background technology.

[0005] To achieve the above objectives, the technical solution of this application is implemented as follows:

[0006] The present invention provides an automatic injection pen, comprising:

[0007] shell;

[0008] A screw, used to push the piston in the injection container to move for injection;

[0009] a dose setting knob for setting the dose by turning;

[0010] a dose indicator ring to indicate the dose to be injected;

[0011] The screw sleeve can rotate along with the rotation of the dose setting knob when setting the dose;

[0012] A dose indicator ring support frame, which rotates in conjunction with the dose indicator ring and the screw sleeve when setting a dose, so as to transmit the torque of the screw sleeve to the dose indicator ring; an elastic arm is provided circumferentially at the distal end of the dose indicator ring support frame, the elastic arm being provided with at least one first externally protruding tooth, and an inner wall of the distal end of the housing being provided with a first internal gear ring that meshes with the first externally protruding tooth; and a clamping claw is provided on the outer wall of the screw sleeve, which extends through the dose indicator ring support frame and is capable of clamping the elastic arm;

[0013] a torsion spring, which rotates along with the rotation of the dose indicator ring support when setting a dose, so as to accumulate torque potential energy;

[0014] The injection button is axially in contact with the screw sleeve; when the injection button is subjected to an axial force toward the distal end, it drives the screw sleeve to move axially toward the distal end, and the clamping claw radially squeezes the elastic arm inward to contract, so that the first external convex tooth is disengaged from the meshing state with the first internal gear ring, thereby releasing the torsion of the torsion spring, pushing the dose indicator ring support frame to rotate, and driving the screw sleeve to rotate, thereby driving the screw to perform a spiral downward motion for injection.

[0015] Optionally, the meshing edges of the tooth profiles of the first inner gear ring and the first outer convex teeth are asymmetrical on both sides, so that the rotational resistance of the dose indicator ring support in a first direction is smaller than the rotational resistance in a second direction; the first direction is the rotation direction of the dose setting knob to increase the dose, and the second direction is the rotation direction of the dose setting knob to decrease the dose.

[0016] Optionally, the elastic arm is provided with a reversal protrusion, which is located on one side of the circumferential rotation trajectory of the clamping jaw; when the screw sleeve rotates in the second direction, the clamping jaw can squeeze the reversal protrusion from the circumferential direction, forcing the elastic arm to shrink inward, reducing the engagement depth of the first external tooth and the first internal gear ring, so as to reduce the resistance to reversal.

[0017] Optionally, the inner wall of the shell is provided with a hook groove for accommodating the hook of the torsion spring; the radial width of the hook groove is greater than the radial width of the hook.

[0018] Optionally, the circumferential length of the inner wall of the hook groove abutting against the hook is shorter than the circumferential length of the hook, so that the hook does not contact the housing at the opening of the hook groove.

[0019] Optionally, the automatic injection pen further comprises:

[0020] A dose limiting lock is mounted on the inner wall of the screw sleeve and is sleeved on the screw; when setting the dose, the rotation of the screw sleeve drives the dose limiting lock to spirally move proximally until the top end of the dose limiting lock abuts the screw and cannot spirally move upward; during injection, the dose limiting lock remains axially stationary relative to the screw; when setting the dose, the stroke of the dose limiting lock that can spirally move on the screw corresponds to the remaining amount of injection liquid in the injection liquid container.

[0021] Optionally, the outer shell includes a tubular body, and the inner wall of the distal end of the tubular body is provided with a first positioning groove and a second positioning groove arranged in axial sequence and both extend axially; the outer wall of the screw bracket is provided with a first positioning protrusion that cooperates with the first positioning groove to limit the circumferential position of the screw bracket; the second positioning groove is used to limit the circumferential position of the injection liquid container.

[0022] Optionally, the automatic injection pen further comprises:

[0023] The first sound-emitting device includes a first sound-emitting structure and a second sound-emitting structure that cooperate with each other; the first sound-emitting structure is arranged at the proximal end of the dose indicator ring, including a third positioning groove and an inclined surface extending to the third positioning groove; the second sound-emitting structure is arranged at the proximal end of the housing, including a third positioning protrusion that matches the third positioning groove; during injection, the dose indicator ring spirally rotates until the third positioning protrusion passes the inclined surface and enters the third positioning groove.

[0024] Optionally, the dose indicator ring comprises scale markings, the scale markings comprising an exhaust mark; the exhaust mark is between the zero scale and the maximum scale.

[0025] Optionally, a fourth circumferential positioning groove is provided at the proximal end of the dose scale ring, and the housing is provided with a fourth positioning protrusion inserted into the fourth positioning groove to limit the axial position of the dose scale ring at zero scale.

[0026] The automatic injection pen of the embodiment of the present application comprises an elastic arm and a first externally protruding tooth provided on the dose indicator ring support frame, and a first internally toothed ring provided on the outer shell. The cooperation between the first externally protruding tooth and the first internally toothed ring maintains the position of the dose indicator ring during dose setting. During injection, a clamping claw provided on the screw sleeve radially clamps the elastic arm, causing it to retract inward, thereby disengaging the first externally protruding tooth from the first internally toothed ring. The torsion force of the torsion spring then drives the screw downward for injection. This results in a simpler structure, and the scale is more stable and accurate during dose setting and injection. Therefore, the automatic injection pen of the embodiment of the present application has a simpler structure, and the scale is more stable and accurate during dose setting and injection.

[0027] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0029] Figure 1 A schematic diagram of the appearance of the automatic injection pen provided in an embodiment of the present application;

[0030] Figure 2 for Figure 1 A cross-sectional view of

[0031] Figure 3 for Figure 2 Schematic diagram after disassembling the injection container;

[0032] Figure 4 This is a schematic diagram (exploded view) of the automatic injection pen provided in an embodiment of the present application;

[0033] Figure 5 A schematic diagram of the assembly of the main components of the automatic injection pen provided in an embodiment of the present application;

[0034] Figure 6 A schematic diagram of a screw and a dose limiting lock in an automatic injection pen provided in an embodiment of the present application;

[0035] Figure 7 A schematic diagram of a dose setting knob in an automatic injection pen provided in an embodiment of the present application;

[0036] Figure 8 A schematic diagram of a screw sleeve in an automatic injection pen provided in an embodiment of the present application;

[0037] Figure 9 A schematic diagram of a dose indicator ring in an automatic injection pen provided in an embodiment of the present application;

[0038] Figure 10 A schematic diagram of a dose indicator ring support frame in an automatic injection pen provided in an embodiment of the present application;

[0039] Figure 11 for Figure 10 A partial enlarged schematic diagram of the middle part structure;

[0040] Figure 12 A schematic diagram of a screw anti-rotation bracket in an automatic injection pen provided in an embodiment of the present application;

[0041] Figure 13A schematic diagram of a fixed end cap in an automatic injection pen provided in an embodiment of the present application from one perspective;

[0042] Figure 14 A schematic diagram of a tube body in an automatic injection pen provided in an embodiment of the present application from one perspective;

[0043] Figure 15 A schematic diagram of a dose indicator ring and a fixed end cap in an automatic injection pen provided in an embodiment of the present application;

[0044] Figure 16 for Figure 15 A partial enlarged schematic diagram of the middle part structure;

[0045] Figure 17 A schematic diagram of the assembly of a fixed end cap and a torsion spring in the automatic injection pen provided in an embodiment of the present application;

[0046] Figure 18 A schematic diagram of a screw support in an automatic injection pen provided in an embodiment of the present application;

[0047] Figure 19 A schematic diagram of another perspective of the tube body in the automatic injection pen provided in an embodiment of the present application;

[0048] Figure 20 A schematic diagram of the connection between the screw sleeve and the injection button in the automatic injection pen provided in an embodiment of the present application;

[0049] Figure 21 for Figure 20 A partial enlarged schematic diagram of point A in the middle;

[0050] Figure 22 Another schematic diagram of the dose indicator ring in the automatic injection pen provided in an embodiment of the present application.

[0051] Description of reference numerals:

[0052] 10. Housing; 11. Tube; 111. First positioning groove; 112. Second positioning groove; 113. First internal gear ring; 114. Second internal thread; 12. Fixed end cap; 122. Third positioning protrusion; 123. Hook groove; 124. Fourth positioning protrusion; 125. Clamping protrusion; 13. Screw bracket; 131. First internal thread; 14. Clamping groove; 15. Window;

[0053] 20. Screw; 21. First external thread; 23. First external plane; 24. Dose limit lock; 241. Rotary linkage positioning protrusion; 25. Second stopper;

[0054] 30. Screw anti-rotation bracket; 31. Fifth outer ring gear; 32. First inner plane;

[0055] 40. Dose setting knob; 41. Second inner gear ring;

[0056] 50. Dose indicator ring; 51. Second external thread; 52. Fourth internal rib; 53. Third positioning groove; 54. Inclined surface; 55. Fourth positioning groove; 56. Exhaust mark;

[0057] 60. Dose indicator ring support; 61. Third inner protrusion; 62. Fourth outer rib; 63. Elastic arm; 631. First outer tooth; 632. Injection protrusion; 633. Reversal protrusion;

[0058] 70. Screw sleeve; 71. Second outer gear ring; 72. Third outer protrusion; 73. Fifth inner gear ring; 74. Rotary linkage positioning groove; 75. Step hole; 76. Clamping claw;

[0059] 81. Injection button; 811. Hook; 812. Button return spring; 82. Torsion spring; 821. Hook;

[0060] 90. Injection container; 91. Piston. DETAILED DESCRIPTION

[0061] To make the technical solutions and beneficial effects of this application more clearly understood, the following detailed description is given by way of specific embodiments. The accompanying drawings are not necessarily drawn to scale, and local features may be enlarged or reduced to more clearly illustrate the details of the local features. Unless otherwise defined, the technical and scientific terms used herein have the same meanings as those in the technical field to which this application belongs.

[0062] In the description of this application, the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "height", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of simplifying the description of this application, and do not indicate that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and should not be understood as a limitation to this application.

[0063] In this application, the terms "first" and "second" are used solely for descriptive purposes and should not be construed as indicating the relative importance of the features indicated or the quantity of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly include at least one of such features. Throughout this application, "plurality" means at least two, such as two or three, and "several" means at least one, such as one, two, or three, unless otherwise specifically defined.

[0064] In this application, unless otherwise expressly defined, the terms "installed," "connected," "connect," "fixed," and "disposed" should be interpreted broadly. For example, "connection" can mean fixed, removable, or integrated; it can mean mechanical or electrical; it can mean direct or indirect connection through an intermediary; it can also mean internal communication between two components or an interaction between two components. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0065] In the present application, unless otherwise explicitly defined, when a first feature is “on,” “above,” “above,” “above,” “below,” “below,” or “below” a second feature, the first feature and the second feature may be in direct contact, or the first feature and the second feature may be in indirect contact via an intermediate medium. Moreover, when a first feature is “on,” “above,” or “above” a second feature, it may mean that the first feature is directly above or obliquely above the second feature, or simply means that the horizontal height of the first feature is higher than the horizontal height of the second feature. When a first feature is “below,” “below,” or “below” a second feature, it may mean that the first feature is directly below or obliquely below the second feature, or simply means that the horizontal height of the first feature is lower than the horizontal height of the second feature.

[0066] In order to fully understand the present application, detailed steps and detailed structures will be presented in the following description to illustrate the technical solution of the present application. The preferred embodiments of the present application are described in detail below. However, in addition to these detailed descriptions, the present application may also have other implementation methods.

[0067] In view of the technical problems in the related art, the present invention provides an automatic injection pen. Figure 1-Figure 5 , the automatic injection pen comprises:

[0068] Housing 10;

[0069] Specifically, the housing 10 may include a distal end connected to the injection liquid container 90 and an opposite proximal end; the housing 10 may have an axially penetrating accommodating cavity.

[0070] It is understood that the proximal end may be Figure 2 The right end of the Figure 2 It can be understood that the distal end and the proximal end are relative, for example, the screw 20 is located at the distal end of the dose setting knob 40, but is located at the proximal end of the injection liquid container 90.

[0071] The screw 20 is used to push the piston 91 in the injection container 90 to move for injection;

[0072] Specifically, the screw 20 may be located in the accommodating cavity; Figure 6 and Figure 18 The outer surface of the screw 20 has a first external thread 21, and the distal end of the housing 10 is provided with a first internal thread 131 matching the first external thread 21; during injection, the screw 20 is driven to rotate, and a spiral motion is formed through the cooperation of the first external thread 21 and the first internal thread 131 to push the piston 91 in the injection liquid container 90 to move axially.

[0073] It is understandable that since the setting of the automatic injection pen is based on a standard and full-capacity injection liquid container 90, in order to keep the injection dose sufficiently accurate, the injection liquid container 90 installed in the automatic injection pen needs to be removed from the automatic injection pen after the injection liquid is injected, and cannot be repeatedly removed and reused.

[0074] Specifically, the first external thread 21 and the first internal thread 131 may be a transmission thread. More specifically, the first external thread 21 and the first internal thread 131 may be trapezoidal threads.

[0075] a dose setting knob 40 for setting a dose by turning;

[0076] Specifically, the dose setting knob 40 can be used to set the dose. When setting the dose, the dose setting knob 40 rotates in a first direction around the axis of the screw 20 to increase the dose, or the dose setting knob 40 rotates in a second direction around the axis of the screw 20 to decrease the dose.

[0077] It is understood that the first direction and the second direction are relative and are not specifically limited. For example, if the first direction is clockwise when viewed from the proximal end, then the second direction is counterclockwise. It is understood that by adjusting the relevant structural arrangements of the components, the first direction may also be counterclockwise when viewed from the proximal end, then the second direction may be clockwise.

[0078] Specifically, refer to Figure 7 and Figure 8 The dose setting knob 40 has a first inner hole, the inner wall of which is provided with a second inner gear ring 41 including at least one meshing tooth. The outer wall of the screw sleeve 70 is provided with a second outer gear ring 71 that cooperates with the second inner gear ring 41. The dose setting knob 40 and the screw sleeve 70 are connected by the second inner gear ring 41 and the second outer gear ring 71 to establish a rotational linkage. It is understood that other structures that can establish a rotational linkage may also be used.

[0079] More specifically, the meshing teeth of the second inner gear ring 41 and the second outer gear ring 71 may be arranged circumferentially, or arranged in a circle circumferentially.

[0080] More specifically, in order to facilitate rapid switching between forward and reverse rotation, at least one of the second inner gear ring 41 and the second outer gear ring 71 is configured to have at least two meshing teeth, and the spacing between adjacent meshing teeth can only accommodate one meshing tooth of the other gear ring.

[0081] a dose indicator ring 50 for indicating the dose to be injected;

[0082] Specifically, the dose indicator ring 50 can be used to indicate the dose to be injected, and can be spirally rotated following the rotation of the dose setting knob 40 .

[0083] Specifically, refer to Figure 9 The outer wall of the dose indicator ring 50 is provided with dose numbers arranged in a spiral direction, i.e., scales.

[0084] The screw sleeve 70 can rotate along with the rotation of the dose setting knob 40 when setting the dose;

[0085] Specifically, the screw sleeve 70 can rotate along with the rotation of the dose setting knob 40; when setting the dose, the screw sleeve 70 rotates in conjunction with the dose indicator ring 50; when injecting, the screw sleeve 70 rotates in conjunction with the screw 20 and the dose indicator ring 50;

[0086] It can be understood that rotational linkage means that when one rotates in a circumferential direction, the other also rotates in the circumferential direction, and there is no distinction between active and driven, which is a two-way linkage.

[0087] Specifically, refer to Figure 14 and Figure 15 The dose indicator ring 50 is provided with a second external thread 51, and the housing 10 is provided with a second internal thread 114 that matches the second external thread 51. In this way, when the dose indicator ring 50 rotates under the drive of the screw sleeve 70, the dose indicator ring 50 spirally rises and falls.

[0088] More specifically, in order to make the dose indicator ring 50 fit more closely to the housing 10 , the second external thread 51 is recessed into the outer wall of the dose indicator ring 50 , and the second internal thread 114 is protruded from the inner wall of the housing 10 .

[0089] Specifically, refer to Figure 8 and Figure 10 The outer wall of the screw sleeve 70 is provided with a third outer protrusion 72, and the inner wall of the dose indicator ring support frame 60 is provided with a third inner protrusion 61 that cooperates with the third outer protrusion 72. The screw sleeve 70 and the dose indicator ring support frame 60 are rotationally linked by the third inner protrusion 61 and the third outer protrusion 72. It is understood that other structures capable of establishing rotational linkage may also be used.

[0090] More specifically, the meshing teeth of the third inner protrusion 61 and the third outer protrusion 72 may be arranged circumferentially, or arranged in a circle circumferentially.

[0091] More specifically, in order to facilitate rapid switching between forward and reverse rotation, at least one of the third inner protrusion 61 and the third outer protrusion 72 is configured to have at least two protrusions, and the spacing between adjacent protrusions can only accommodate one protrusion of the other.

[0092] The dose indicator ring support frame 60 rotates in conjunction with the dose indicator ring 50 and the screw sleeve 70 when setting a dose, thereby transmitting the torque of the screw sleeve 70 to the dose indicator ring 50. A resilient arm 63 is circumferentially provided at the distal end of the dose indicator ring support frame 60. The resilient arm 63 is provided with at least one first externally protruding tooth 631. The inner wall of the distal end of the housing 10 is provided with a first internal gear ring 113 that meshes with the first externally protruding tooth 631. A clamping claw 76 is provided on the outer wall of the screw sleeve 70, extending through the dose indicator ring support frame 60 and capable of clamping the resilient arm 63.

[0093] Specifically, the dose indicator ring support frame 60 can be used to transmit the torque of the screw sleeve 70 to the dose indicator ring 50; when setting the dose, the dose indicator ring support frame 60 rotates in conjunction with the dose indicator ring 50 and the screw sleeve 70; Figure 8 and Figure 10 An elastic arm 63 is provided on the circumference of the distal end of the dose indicator ring support frame 60, and at least one first external protruding tooth 631 is provided on the elastic arm 63. The inner wall of the distal end of the shell 10 is provided with a first internal gear ring 113 that meshes with the first external protruding tooth 631; the outer wall of the screw sleeve 70 is provided with a clamping claw 76 that passes through the dose indicator ring support frame 60 and can clamp the elastic arm 63.

[0094] The elasticity of the elastic arm 63 is used to maintain the meshing state between the first external protruding teeth 631 and the first internal gear ring 113 .

[0095] It can be understood that the meshing state of the first outer protruding teeth 631 and the first inner gear ring 113 can hinder the circumferential rotation of the dose indicator ring support 60, so as to overcome the torque potential energy of the torsion spring 82 and maintain the position of the dose indicator ring 50 in the dose setting stage when the injection stage is not entered.

[0096] Specifically, refer to Figure 9 and Figure 10The outer wall of the dose indicator ring support frame 60 is provided with a fourth outer rib 62, and the inner wall of the dose indicator ring 50 is provided with a fourth inner rib 52 that cooperates with the fourth outer rib 62. The fourth inner rib 52 and the fourth outer rib 62 establish a rotational linkage between the dose indicator ring 50 and the dose indicator ring support frame 60. It is understood that other structures that can establish a rotational linkage are also possible.

[0097] When the screw sleeve 70 and the dose indicator ring support frame 60 are in a rotationally linked relationship, and the dose indicator ring 50 and the dose indicator ring support frame 60 are in a rotationally linked relationship, the screw sleeve 70 and the dose indicator ring 50 are in a rotationally linked relationship. It is understood that other structures capable of establishing rotational linkage may also be used.

[0098] More specifically, the ribs of the fourth inner rib 52 and the fourth outer rib 62 may be arranged circumferentially, or arranged in a circle circumferentially.

[0099] More specifically, in order to facilitate rapid switching between forward and reverse rotation, at least one of the fourth inner rib 52 and the fourth outer rib 62 is configured to have at least two ribs, and the spacing between adjacent ribs can only accommodate one rib of the other.

[0100] It can be understood that one end of the elastic arm 63 in the circumferential direction is a cantilever, so the cantilever can generate radial elasticity to maintain the meshing state between the first outer protruding tooth 631 and the first inner gear ring 113 .

[0101] a torsion spring 82 , which rotates along with the rotation of the dose indicator ring support 60 when setting a dose, so as to accumulate torque potential energy;

[0102] Specifically, the proximal end of the torsion spring 82 is connected to the housing 10 , and the distal end is connected to the dose indicator ring support 60 ; when setting a dose, the torsion spring 82 rotates along with the rotation of the dose indicator ring support 60 to accumulate torque potential energy.

[0103] Specifically, refer to Figure 11 The proximal and distal ends of the torsion spring 82 are both provided with connecting portions. More specifically, the connecting portion can be a hook 821. The proximal connecting portion of the torsion spring 82 is connected to the housing 10, and the distal connecting portion is connected to the dose indicator ring support 60.

[0104] The injection button 81 is in axial contact with the screw sleeve 70; when the injection button 81 is subjected to an axial force toward the distal end, it drives the screw sleeve 70 to move axially toward the distal end, and the clamping jaw 76 radially squeezes the elastic arm 63 to contract inward, so that the first outer protruding tooth 631 is disengaged from the first inner gear ring 113, thereby releasing the torsion force of the torsion spring 82, pushing the dose indicator ring support 60 to rotate, and driving the screw sleeve 70 to rotate, thereby driving the screw 20 to perform a spiral downward motion for injection.

[0105] Specifically, the injection button 81 can be axially abutted against the screw sleeve 70; the injection button 81 moves axially toward the distal end, and the automatic injection pen enters the injection working state; the injection button 81 drives the screw sleeve 70 to move axially toward the distal end, and radially clamps the elastic arm 63 through the clamping jaw 76, causing the elastic arm 63 to contract inward, thereby causing the first external protruding tooth 631 to disengage from the meshing state with the first internal gear ring 113; the dose indicator ring support frame 60 rotates in the second direction under the torsion force of the torsion spring 82; driving the screw sleeve 70 to rotate, and then driving the screw 20 to perform a spiral downward motion for injection.

[0106] Specifically, refer to Figure 8 and Figure 10 , an injection protrusion 632 is provided on the elastic arm 63. The outer diameter of the injection protrusion 632 gradually increases from the proximal end to the distal end. Therefore, when the screw sleeve 70 moves axially toward the distal end, the clamping radius of the injection protrusion 632 gradually increases, forcing the elastic arm 63 to retract inward. Specifically, the clamping jaw 76 passes through the dose indicator ring support frame 60, so that the clamping jaw 76 can clamp the elastic arm 63 from the radial direction. In the case of no injection, the clamping jaw 76 remains axially stationary and only lightly contacts the elastic arm 63. In the case of injection, the axial movement of the screw sleeve 70 can cause the clamping jaw 76 to gradually contact the part with a larger outer diameter of the injection protrusion 632, thereby achieving the effect of retracting the elastic arm 63.

[0107] More specifically, the injection protrusion is provided with a tapered surface or a curved surface such that the outer diameter gradually increases from the proximal end to the distal end.

[0108] Specifically, refer to Figure 1 The injection button 81 is provided with a button return spring 812 to push the injection button 81 to return to its original position after the injection is completed.

[0109] Specifically, the automatic injection pen may further include a screw stop frame 30, which is rotatably mounted on the inner wall of the distal end of the housing 10 and is rotationally linked with the screw 20; during injection, the screw sleeve 70 moves axially toward the distal end and establishes a rotational linkage with the screw stop frame 30, so that the screw sleeve 70 and the screw 20 are rotationally linked.

[0110] Specifically, during injection, the screw sleeve 70 moves distally under the influence of the injection button 81. Once at a certain position, it circumferentially couples with the screw stop 30, establishing a rotational linkage. As the screw sleeve 70 rotates, driven by the dose indicator ring support 60, the screw stop 30 rotates with it. Furthermore, the screw stop 30 and the screw 20 are rotationally linked, so rotation of the screw stop 30 drives rotation of the screw 20. Combined with the previously described interaction between the first external thread 21 and the first internal thread 131, the screw 20 undergoes a helical rotational motion.

[0111] Specifically, refer to Figure 8 The inner wall of the screw sleeve 70 is provided with a fifth inner gear ring 73 including at least one meshing tooth, and the outer wall of the screw anti-rotation frame 30 is provided with a fifth outer gear ring 31 that cooperates with the fifth inner gear ring 73. Through the fifth inner gear ring 73 and the fifth outer gear ring 31, the screw sleeve 70 and the screw anti-rotation frame 30 establish a rotational linkage relationship. It is understood that other structures that can establish rotational linkage may also be used.

[0112] More specifically, the meshing teeth of the fifth inner gear ring 73 and the fifth outer gear ring 31 may be arranged along the circumferential direction, or arranged in a circle along the circumferential direction.

[0113] More specifically, in order to facilitate rapid switching between forward and reverse rotation, at least one of the fifth inner gear ring 73 and the fifth outer gear ring 31 is configured to have at least two meshing teeth, and the spacing between adjacent meshing teeth can only accommodate one meshing tooth of the other gear ring.

[0114] Specifically, refer to Figure 6 and Figure 12 The outer circumferential surface of the screw rod 20 is provided with at least one first outer flat surface 23. The screw stop 30 has a second inner hole and is sleeved onto the push rod. The inner wall of the second inner hole is provided with at least one first inner flat surface 32 that mates with the first outer flat surface 23. The screw rod 20 and the screw stop 30 establish a rotational linkage through the first outer flat surface 23 and the first inner flat surface 32.

[0115] More specifically, the outer circumferential surface of the screw 20 may be provided with two symmetrical first outer planes 23, and correspondingly, the second inner hole is also provided with two first inner planes 32, forming a waist-shaped hole, which is more convenient for processing.

[0116] It should be noted that when setting a dose, the screw sleeve 70 remains axially stationary, and the screw stop 30 and the screw sleeve 70 are not circumferentially linked. Consequently, the screw sleeve 70 and the screw 20 cannot establish a rotational linkage. Thus, when setting a dose, the screw sleeve 70 rotates, driving the dose indicator ring support 60, which in turn drives the dial, while the screw 20 remains stationary.

[0117] It is understandable that the automatic injection pen of the embodiment of the present application is an injection pen that injects a set dose, and therefore includes two working states: setting the dose and injecting, or two stages: setting the dose and injecting. The following briefly describes the working process of the two working states:

[0118] 1) Setting the dose. Turning the dose setting knob 40 rotates the screw sleeve 70, which in turn rotates the dose indicator ring support 60, which in turn rotates the dose indicator ring 50. Because the dose indicator ring 50 has a second external thread 51 and the housing 10 has a second internal thread 114, the dose indicator ring 50 spirals upward and downward, and the corresponding scale can be seen through the transparent or hollow window 15 of the housing 10. Therefore, the desired dose can be set by turning the dose setting knob 40.

[0119] Specifically, before setting a dose, the dose indicator ring 50 is located at the proximal end, the window 15 of the housing 10 displays the zero scale, and the dose indicator ring 50 can only move distally and cannot move in the reverse direction (referred to as the proximal lock position). The dose setting knob 40 can only rotate in a first direction to increase the dose, i.e., forward rotation, and cannot rotate in the reverse direction. Only when the scale is not zero can the dose setting knob 40 be rotated in a second direction to decrease the dose. For example, when the dose exceeds the required dose during adjustment, the dose can be reduced by reverse rotation. The dose indicator ring 50 moves in the reverse direction, but the resistance to reverse rotation is greater than the resistance to forward rotation.

[0120] At the same time, the rotation of the dose indicator ring support 60 drives the torsion spring 82 to rotate, accumulating torque potential energy. Furthermore, the first externally protruding tooth 631 and the first internally toothed ring 113 remain engaged under the elastic force of the elastic arm 63. Without external force, the accumulated torque potential energy of the torsion spring 82 cannot drive the dose indicator ring support 60 to rotate in the opposite direction.

[0121] It should be noted that when setting the dose, the screw 20 remains stationary both in the axial direction and the circumferential direction to maintain the accuracy of the injection dose.

[0122] 2) Injection. The injection button 81 is pressed axially, pushing the screw sleeve 70 axially distally. The clamping jaws 76 of the screw sleeve 70 radially clamp the elastic arms 63, causing them to contract inwardly, thereby disengaging the first externally protruding teeth 631 from the first internal gear ring 113. The torque potential energy of the torsion spring 82 is released, driving the dose indicator ring support 60 to rotate in the opposite direction. This reverse rotation of the dose indicator ring support 60 drives the screw sleeve 70 to rotate in the opposite direction. The reverse rotation of the screw sleeve 70 drives the screw 20 to rotate in the opposite direction, causing the screw 20 to spiral distally, squeezing the piston 91 in the injection liquid container 90 and ejecting the injection liquid.

[0123] At the same time, the dose indicator ring 50 also spirals up and down following the rotation of the dose indicator ring support 60, gradually decreasing the scale until the window 15 of the housing 10 returns to the zero scale, and the dose indicator ring 50 returns to the proximal locking position. Since the dose indicator ring 50 can no longer move after returning to the proximal locking position, the torque potential energy of the torsion spring 82 can no longer drive the dose indicator ring support 60 to rotate in the opposite direction, and accordingly, the accumulated torque potential energy of the torsion spring 82 is completely released.

[0124] As will be understood, as previously described, an injection can only be performed after the dose is set and the window 15 of the housing 10 displays a value other than zero, i.e., the scale is greater than zero. As will be understood, when the scale is greater than zero, the position of the dose indicator ring 50 (referred to as the dose setting position), i.e., the distance the screw travels from the proximal locking position, corresponds to the scale. That is, during an injection, the dose indicator ring 50 moves from the dose setting position to the proximal locking position, or in other words, the window 15 of the housing 10 moves from the set scale to the zero scale. The screw 20 can then, through axial movement, cause the injection container 90 to inject the set dose. This requires structural design based on calculations to ensure that the movement of the dose indicator ring 50 and the screw 20 are compatible, for example, by ensuring that the first external thread 21 and the second external thread 51 have an appropriate pitch.

[0125] As will be understood, the autoinjector pen of the present embodiment requires use with an injection container 90. The injection container 90 can be a cartridge, with the distal end of the cartridge serving as an injection outlet and the proximal end being provided with a piston 91, typically a rubber stopper. After the injection container 90 is mounted in the autoinjector pen, the screw 20 is axially connected to the piston 91. This allows the axial movement of the screw 20 to push the piston 91 distally, squeezing the injection liquid out of the injection outlet. It is understood that other types of injection containers 90 are also possible.

[0126] The automatic injection pen of the present embodiment comprises an elastic arm 63 and a first externally protruding tooth 631 provided on the dose indicator ring support frame 60, and a first internally protruding tooth 113 provided on the housing. The cooperation between the first externally protruding tooth 631 and the first internally protruding tooth 113 maintains the position of the dose indicator ring 50 during dose setting. During injection, the clamping jaws 76 provided on the screw sleeve 70 radially clamp the elastic arm 63, causing it to retract inward, thereby disengaging the first externally protruding tooth 631 from the first internally protruding tooth 113. The torsion force of the torsion spring 82 then drives the screw 20 downward for injection. This results in a simpler structure and more stable and accurate scale during dose setting and injection.

[0127] Furthermore, compared to other embodiments, the technical solution of maintaining the position of the dose indicator ring 50 by meshing the end face gear ring has the following advantages:

[0128] A) The scale is more stable. The motion trajectory of the end face gear ring is circular motion, which is similar to the motion direction of the torque of the torsion spring. It is more easily affected by the force of the torsion spring, resulting in an unstable state of the end face gear ring, which in turn affects the stability of the scale. The technical solution of this embodiment is to use an elastic arm, whose motion trajectory is radial motion, which is not easily affected by the force of the torsion spring and causes unexpected changes in the scale. In addition, the elastic arm of this embodiment is less affected by the impact or vibration than the axial spring (hereinafter referred to as the gear ring spring) acting on the end face gear ring. For example, in an impact test, it is not easy to be deformed by impact or vibration, causing the end face gear ring to rotate and change the scale value. Therefore, the scale is more stable.

[0129] B) Dose setting is more labor-efficient. With the end-face gear ring approach, dose setting requires overcoming the elastic force of the gear ring spring (hereinafter referred to as the gear ring spring), resulting in significant resistance and increased effort. However, with the elastic arm of this embodiment, dose setting only requires overcoming the radial elastic force of the elastic arm, which can be easily overcome by rotating the arm in the circumferential direction during dose setting.

[0130] C) Easier injection. Similarly, with the end-face gear ring approach, injection requires not only overcoming the spring force of the injection button but also the spring force of the gear ring spring, making injection more laborious. However, the elastic arm of this embodiment offers less axial resistance, making injection more labor-efficient.

[0131] In other embodiments of the present application, reference is made to Figure 14 The meshing edges of the tooth profiles of the first inner gear ring 113 and the first outer convex teeth 631 are asymmetrical on both sides, so that the rotational resistance of the dose indicator ring support frame 60 in the first direction is smaller than the rotational resistance in the second direction; the first direction is the rotation direction of the dose setting knob to increase the dose, and the second direction is the rotation direction of the dose setting knob to decrease the dose.

[0132] Specifically, the tooth shapes of the first inner gear ring 113 and the first outer protruding teeth 631 can be non-isosceles triangles. This simplifies the structure. It is understood that other shapes, such as non-isosceles trapezoids, are also possible.

[0133] It will be appreciated that in this embodiment, the resistance to clockwise rotation of the dose indicator ring support 60 as viewed from the proximal end is less than the resistance to counterclockwise rotation (when the housing 10 is stationary). Therefore, in this embodiment, the first direction is the clockwise direction as viewed from the proximal end, and the second direction is the counterclockwise direction as viewed from the proximal end. It is understood that the reverse direction is also possible, with other components being designed accordingly.

[0134] Furthermore, the meshing edges of the first inner gear ring 113 and the first outer protruding teeth 631 are asymmetrically arranged. This not only results in different rotational resistances for forward and reverse rotation, but also different sounds for forward and reverse rotation, thus reminding the user whether the current operation is forward or reverse, thereby reducing operational errors.

[0135] Specifically, the inclination angle of one meshing edge between the first inner gear ring 113 and the first outer protruding teeth 631 is 10°-45°, and the inclination angle of the other meshing edge is 60°-90°.

[0136] In other embodiments of the present application, the elastic arm is provided with a reversal protrusion 633, and the reversal protrusion 633 is located on one side of the circumferential rotation trajectory of the clamping jaw; when the screw sleeve rotates in the second direction, the clamping jaw can squeeze the reversal protrusion 633 from the circumferential direction, forcing the elastic arm to shrink inward, reducing the engagement depth of the first external tooth and the first internal gear ring, so as to reduce the resistance to reversal.

[0137] For example, reference Figure 10 , the reversal direction of the screw sleeve is clockwise ( Figure 10 This is the perspective viewed from the far end, such as counterclockwise when viewed from the proximal end). In this way, when the clamping claw of the screw sleeve rotates clockwise, it will squeeze the reversal protrusion 633 from the circumferential direction, forcing the elastic arm to shrink inward.

[0138] In other embodiments of the present application, reference is made to Figure 13 and Figure 17 The inner wall of the housing 10 is provided with a hook groove 123 for accommodating the hook 821 of the torsion spring 82 ; the radial width of the hook groove 123 is greater than the radial width of the hook 821 .

[0139] This increases the installation space for the torsion spring 82 to be installed in the hook slot 123, reducing the difficulty of installing the torsion spring 82. Furthermore, when the torsion spring 82 is subjected to force, the space for the torsion spring 82 to deform is increased, reducing the possibility of the torsion spring 82 exploding under force, which could cause the autoinjector pen to fail.

[0140] Specifically, the radial width of the hook groove 123 is greater than the radial width of the hook 821 by 1.4 mm to 1.8 mm.

[0141] In other embodiments of the present application, continue to refer to Figure 13 The circumferential length of the inner wall of the hook groove 123 abutting against the hook 821 is shorter than the circumferential length of the hook 821 , so that the hook 821 does not contact the housing 10 at the opening of the hook groove 123 .

[0142] In this way, the movement of the base of the torsion spring 82 hook 821 is not restricted, which increases the deformation space of the torsion spring 82 and reduces the possibility of the torsion spring 82 exploding when subjected to force, causing failure of the autoinjector pen. It also reduces the possibility of the torsion spring 82 deforming under force and squeezing the housing 10, which may cause damage.

[0143] In other embodiments of the present application, reference is made to Figure 6 , the automatic injection pen further comprises:

[0144] The dose limiting lock 24 is mounted on the inner wall of the screw sleeve 70 and is sleeved on the screw 20; when setting the dose, the rotation of the screw sleeve 70 drives the dose limiting lock 24 to spirally move proximally until the top end of the dose limiting lock 24 abuts the screw 20 and cannot spirally move upward; during injection, the dose limiting lock 24 remains axially stationary relative to the screw 20; when setting the dose, the stroke of the dose limiting lock 24 that can spirally move on the screw 20 corresponds to the remaining amount of injection liquid in the injection liquid container 90.

[0145] It should be noted that a radially protruding second stopper 25 is provided at the proximal end of the screw 20. In an initial state before use, the distance between the proximal end of the dose limiter lock 24 and the distal end of the second stopper 25 is a predetermined first axial distance. This first axial distance is consistent with the capacity of the injection container 90 used with the autoinjector pen and also determines the maximum injection dose of the autoinjector pen.

[0146] Specifically, in this embodiment, to improve injection accuracy and facilitate portability, the dose set for a single injection is smaller than the capacity of the injection container 90. Furthermore, the autoinjector pen can be used for multiple injections with a single injection container 90 installed, eliminating the need to install a new injection container 90 for each injection, further enhancing user convenience. The following examples illustrate this.

[0147] For example, a commonly used injection container 90 holds 3 ml, while the single injection volume of the autoinjector pen of this embodiment is 0.75 ml. This means that four injections are required to completely inject the injection container 90. When the 0.75 ml dose is first set, the dose limiter lock 24 spirals proximally following the rotation of the screw sleeve 70, stopping at 1 / 4 of its maximum travel. This means that the distance between the dose limiter lock 24 and the screw 20 is 3 / 4 of the first axial distance. During the first injection, since the screw 20 and the dose limiter lock 24 also spiral in the same direction, the axial distance between them remains unchanged. When the next 75 ml dose is set, the distance between the dose limiter lock 24 and the screw 20 is 2 / 4 of the first axial distance. When the final 75 ml dose is set, the distance between the dose limiter lock 24 and the screw 20 is "0," completing the maximum injection dose, and the injection container 90 is disassembled and discarded.

[0148] It is understood that the dose set each time can be less than 0.75 ml, so that the number of injections is greater than 4 times.

[0149] The dose limiting lock 24 can prevent the set dose from exceeding the amount of infusion solution remaining in the infusion solution container 90 .

[0150] Specifically, refer to Figure 20 The inner wall of the screw sleeve 70 is provided with a rotation linkage positioning groove 74, and the outer wall of the dose limit lock 24 is provided with a rotation linkage positioning protrusion 241 that cooperates with the rotation linkage positioning groove 74. Through the rotation linkage positioning groove 74 and the rotation linkage positioning protrusion 241, the screw sleeve 70 and the dose limit lock 24 establish a rotation linkage relationship. It is understood that other structures that can establish rotation linkage may also be used.

[0151] Specifically, the rotation linkage positioning groove 74 and the fifth inner gear ring 73 are staggered in the axial direction to avoid mutual interference.

[0152] As previously mentioned, when setting a dose, the dose indicator ring 50 spirally moves distally. To limit the dose for a single injection, a first stopper is provided at the distal end of the housing 10 to axially block the spiral movement of the dose indicator ring 50 so that the maximum scale setting does not exceed the designed value.

[0153] In other embodiments of the present application, reference is made to Figure 20 and Figure 21 The injection button 81 and the screw sleeve 70 are provided with an axially connected hook 811 connection structure to make the axial connection more stable. Figure 20 and Figure 21The inverted hook 811 connection structure includes a inverted hook 811 and a stepped hole 75. The stepped hole 75 includes a first through hole and a second through hole with a larger aperture than the first through hole. The inverted hook 811 passes through the first through hole and enters the second through hole, and the connection is completed by hooking the shoulder between the two through holes through the inverted hook 811.

[0154] In other embodiments of the present application, reference is made to Figure 4 The housing 10 includes a tube body 11 and a screw bracket 13 , wherein the screw bracket 13 is fixed to the inner wall of the distal end of the tube body 11 ; the screw bracket 13 is provided with the first internal thread 131 .

[0155] That is, instead of directly machining the screw support 13 on the outer shell 10, the outer shell 10 is divided into the tube body 11 and the screw support 13, wherein the first internal thread 131 is provided on the screw support 13. This makes machining and assembly easier. It is understood that the screw support 13 can also be formed integrally with the tube body 11.

[0156] In other embodiments of the present application, reference is made to Figure 19 The inner wall of the distal end of the tube body 11 is provided with a first positioning groove 111 and a second positioning groove 112 arranged in axial sequence, and both extend axially; the outer wall of the screw bracket 13 is provided with a first positioning protrusion that cooperates with the first positioning groove 111 to limit the circumferential position of the screw bracket 13; the second positioning groove 112 is used to limit the circumferential position of the injection liquid container 90.

[0157] In this way, the circumferential position of the screw support 13 can be better limited, and the structure is simple and the processing cost is low.

[0158] Similarly, the circumferential position of the injection liquid container 90 can be better limited, and the structure is simple and the processing cost is low.

[0159] Specifically, the second positioning groove 112 and the first positioning groove 111 are aligned in the circumferential direction, so as to facilitate the processing of the tube body 11 .

[0160] In other embodiments of the present application, reference is made to Figure 9 and Figure 13 , the automatic injection pen further comprises:

[0161] The first sound-emitting device includes a first sound-emitting structure and a second sound-emitting structure that cooperate with each other; the first sound-emitting structure is arranged at the proximal end of the dose indicator ring 50, and includes a third positioning groove 53 and an inclined surface 54 extending into the third positioning groove 53; the second sound-emitting structure is arranged at the proximal end of the housing 10, and includes a third positioning protrusion 122 that matches the third positioning groove 53; during injection, the dose indicator ring 50 spirally rotates until the third positioning protrusion 122 passes the inclined surface 54 and enters the third positioning groove 53.

[0162] As can be understood, near the end of the injection, the dose indicator ring 50 spirally rotates, causing the inclined surface 54 to abut against the third positioning projection 122, forcing the third positioning projection 122 to deform during the spiral rotation. As the dose indicator ring 50 continues to rotate, the third positioning projection 122 falls into the third positioning groove 53, and the deformed portion of the third positioning projection 122 is released, emitting a sound different from that of an injection, notifying the user that the injection is complete.

[0163] Specifically, the third positioning protrusion 122 may be compressed and deformed by an amount of 0.3-1.2 mm.

[0164] It can be understood that the cooperation between the third positioning groove 53 and the third positioning protrusion 122 , in addition to producing a sound, can also play a certain role in limiting the circumferential position of the dose indicator ring 50 .

[0165] In other embodiments of the present application, reference is made to Figure 13 The housing 10 further includes a fixed end cover 12, which is fixed to the inner wall of the proximal end of the tube body 11; the distal end of the fixed end cover 12 is provided with the second sound-generating structure.

[0166] That is, the second sound-generating structure is not directly processed on the outer shell 10 , but the outer shell 10 is divided into a tube body 11 and a fixed end cover 12 , wherein the second sound-generating structure is arranged on the fixed end cover 12 .

[0167] This makes processing and assembly easier. It is understandable that the fixed end cap 12 and the tube body 11 can also be formed in one piece.

[0168] Furthermore, the third positioning protrusion 122 , the fourth positioning protrusion 124 and the hook groove 123 may also be provided on the fixed end cover 12 , which makes processing and assembly easier.

[0169] In other embodiments of the present application, the tube body 11 and the fixed end cover 12 are provided with a snap-fit ​​connection structure to make the axial connection more stable. Figure 13 and Figure 19 The snap connection structure includes a snap protrusion 125 and a snap slot 14, and the snap protrusion 125 is snapped into the snap slot 14 to complete the connection.

[0170] In other embodiments of the present application, reference is made to Figure 5 and Figure 22 The dose indicator ring 50 includes scale markings, and the scale markings include an exhaust mark 56; the exhaust mark 56 is between the zero scale and the maximum scale.

[0171] In this way, the gas in the injection liquid container 90 can be discharged before injection, making it safer to use.

[0172] Specifically, the dose is set, the dose scale is rotated to the exhaust mark 56, and then the injection is performed. After the injection is completed, the dose is set again, the dose scale is rotated to the exhaust mark 56, and the injection is performed. This operation is repeated several times to complete the exhaust. After that, the dose setting and injection can be resumed normally.

[0173] Specifically, the exhaust mark 56 is between the zero scale and the "02" scale, so that the gas can be exhausted without affecting the injection.

[0174] In other embodiments of the present application, reference is made to Figure 15 and Figure 16 A fourth circumferential positioning groove 55 is provided at the proximal end of the dose scale ring, and the housing 10 is provided with a fourth positioning protrusion 124 inserted into the fourth positioning groove 55 to limit the axial position of the dose scale ring at the zero scale.

[0175] It can be understood that after the fourth positioning protrusion 124 enters the fourth positioning groove 55 and circumferentially abuts against it, the dose indicator ring 50 is located at the zero scale, or in other words, the window 15 of the housing 10 displays the zero scale. The fourth positioning groove 55 and the fourth positioning protrusion 124 can more reliably maintain the dose indicator ring 50 at the zero scale position.

[0176] It should be noted that, since the dose indicator ring 50 and the housing 10 are threadedly connected via the second external thread 51 and the second internal thread 114, and the second internal thread 114 has relatively few threads, the limiting effect of the fourth positioning groove 55 and the fourth positioning protrusion 124 can also prevent the second external thread 51 and the second internal thread 114 from being detached from the threaded connection.

[0177] It should be noted that the fourth positioning projection 124 enters the fourth positioning groove 55 and circumferentially abuts against it after the first sound-generating device emits a sound, to prevent the first sound-generating device from being unable to produce a sound. Furthermore, the fourth positioning projection 124 enters the fourth positioning groove 55 and circumferentially abuts against it immediately after the first sound-generating device emits a sound. This means that the timing of these two actions is closely aligned, thus improving the injection accuracy of the autoinjector pen.

[0178] It should be understood that the above embodiments are exemplary and are not intended to encompass all possible implementations of the claims. Various modifications and variations may be made to the above embodiments without departing from the scope of the present disclosure. Similarly, the various technical features of the above embodiments may be arbitrarily combined to form additional embodiments of the present application that may not be explicitly described. Therefore, the above embodiments merely represent several implementations of the present application and do not limit the scope of protection of the patent application.

Claims

1. An automatic injection pen, characterized in that: include: shell; A screw, used to push the piston in the injection container to move for injection; a dose setting knob for setting the dose by turning; a dose indicator ring to indicate the dose to be injected; The screw sleeve can rotate along with the rotation of the dose setting knob when setting the dose; A dose indicator ring support frame, which rotates in conjunction with the dose indicator ring and the screw sleeve when setting a dose, so as to transmit the torque of the screw sleeve to the dose indicator ring; an elastic arm is provided circumferentially at the distal end of the dose indicator ring support frame, the elastic arm being provided with at least one first externally protruding tooth, and an inner wall of the distal end of the housing being provided with a first internal gear ring that meshes with the first externally protruding tooth; and a clamping claw is provided on the outer wall of the screw sleeve, which extends through the dose indicator ring support frame and is capable of clamping the elastic arm; a torsion spring, which rotates along with the rotation of the dose indicator ring support when setting a dose, so as to accumulate torque potential energy; The injection button is axially in contact with the screw sleeve; when the injection button is subjected to an axial force toward the distal end, it drives the screw sleeve to move axially toward the distal end, and the clamping claw radially squeezes the elastic arm inward to contract, so that the first external convex tooth is disengaged from the meshing state with the first internal gear ring, thereby releasing the torsion of the torsion spring, pushing the dose indicator ring support frame to rotate, and driving the screw sleeve to rotate, thereby driving the screw to perform a spiral downward motion for injection.

2. The automatic injection pen according to claim 1, characterized in that The meshing edges of the tooth profiles of the first inner gear ring and the first outer convex teeth are asymmetrical on both sides, so that the rotational resistance of the dose indicator ring support in a first direction is smaller than the rotational resistance in a second direction; the first direction is the rotational direction of the dose setting knob to increase the dose, and the second direction is the rotational direction of the dose setting knob to decrease the dose.

3. The automatic injection pen according to claim 1, characterized in that The elastic arm is provided with a reversal protrusion, which is located on one side of the circumferential rotation trajectory of the clamping jaw; when the screw sleeve rotates in the second direction, the clamping jaw can squeeze the reversal protrusion from the circumferential direction, forcing the elastic arm to shrink inward, reducing the engagement depth of the first external protruding tooth and the first internal gear ring, so as to reduce the resistance to reversal.

4. The automatic injection pen according to claim 1, characterized in that The inner wall of the shell is provided with a hook groove for accommodating the hook of the torsion spring; the radial width of the hook groove is greater than the radial width of the hook.

5. The automatic injection pen according to claim 4, characterized in that The circumferential length of the inner wall of the hook groove abutting against the hook is shorter than the circumferential length of the hook, so that the hook does not contact the housing at the opening of the hook groove.

6. The automatic injection pen according to claim 1, characterized in that The automatic injection pen further comprises: A dose limiting lock is mounted on the inner wall of the screw sleeve and is sleeved on the screw; when setting the dose, the rotation of the screw sleeve drives the dose limiting lock to spirally move proximally until the top end of the dose limiting lock abuts the screw and cannot spirally move upward; during injection, the dose limiting lock remains axially stationary relative to the screw; when setting the dose, the stroke of the dose limiting lock that can spirally move on the screw corresponds to the remaining amount of injection liquid in the injection liquid container.

7. The automatic injection pen according to claim 6, characterized in that The outer shell includes a tubular body, and the inner wall of the distal end of the tubular body is provided with a first positioning groove and a second positioning groove arranged in axial sequence, and both extend axially; the outer wall of the screw bracket is provided with a first positioning protrusion that cooperates with the first positioning groove to limit the circumferential position of the screw bracket; the second positioning groove is used to limit the circumferential position of the injection liquid container.

8. The automatic injection pen according to claim 1, characterized in that The automatic injection pen further comprises: The first sound-emitting device includes a first sound-emitting structure and a second sound-emitting structure that cooperate with each other; the first sound-emitting structure is arranged at the proximal end of the dose indicator ring, including a third positioning groove and an inclined surface extending to the third positioning groove; the second sound-emitting structure is arranged at the proximal end of the housing, including a third positioning protrusion that matches the third positioning groove; during injection, the dose indicator ring spirally rotates until the third positioning protrusion passes the inclined surface and enters the third positioning groove.

9. The automatic injection pen according to claim 1, characterized in that The dose indicator ring includes scale markings, and the scale markings include an exhaust mark; the exhaust mark is between the zero scale and the maximum scale.

10. The automatic injection pen according to claim 1, characterized in that A fourth circumferential positioning groove is provided at the proximal end of the dose scale ring, and the housing is provided with a fourth positioning protrusion inserted into the fourth positioning groove to limit the axial position of the dose scale ring at zero scale.

Images