Injector pen and its dose adjustment mechanism.

Abstract

An injection pen and a dose adjustment mechanism thereof. The dose adjustment mechanism comprises a power rod, a barrel body, a ball, a sleeve, and a torsion spring. The barrel body is sleeved outside the power rod. A spiral channel extending in an axial direction of the power rod is formed between an inner barrel wall of the barrel body and an outer rod wall of the power rod. The ball is rollably arranged in the spiral channel. The barrel body is relatively fixed to an upper pen barrel of the injection pen in a circumferential direction. The upper end of the torsion spring is relatively fixed to the upper pen barrel, and the lower end of the torsion spring is connected to the sleeve. The power rod can rotate relative to the barrel body under the action of external force. The sleeve is in circumferential limiting connection to the power rod. The sleeve is configured for being in transmission fit with a transmission mechanism of the injection pen. By means of structural optimization, the rolling smoothness of the ball in the dose adjustment mechanism can be ensured, so that the ball can be smoothly reset, thereby improving the reliability and safety during the use of the injection pen.

Description

1 / 20 “INJECTOR PEN AND ITS DOSE ADJUSTMENT MECHANISM”

[001] This application claims priority to Chinese patent application no. 202410058074.4, entitled INJECTOR PEN AND DOSE ADJUSTMENT MECHANISM THEREOF, filed on January 16, 2024 with the China National Intellectual Property Administration, which is incorporated herein by reference in its entirety. FIELD

[002] This application relates to the technical field of medical devices and, in particular, to an injector pen and a dose adjustment mechanism for the injector pen. FUNDAMENTALS

[003] Insulin injection therapy is the most commonly used treatment method in clinical work, which generates injector pens for insulin injection. Injector pens can be used repeatedly and adjust the injection dose precisely. Only the cartridges containing insulin need to be replaced. In addition to insulin injection, injector pens can also be used to inject other medications.

[004] In the related technique, an injector pen includes an upper pen holder assembly and a lower pen cap. The upper pen holder assembly includes a push-button mechanism, a dose adjustment mechanism, and a transmission mechanism. The lower pen cap is used to mount the cartridge. Kinetic energy can be stored by the operation of the dose adjustment mechanism. Under the pressure operation of a push-button mechanism, the kinetic energy stored in the dose adjustment mechanism can be released, and the cartridge retaining stopper can be pushed by the transmission mechanism to perform the injection of the drug.

[005] To obtain precise control of drug injection, the dose adjustment mechanism generally adopts the ball screw principle. However, in Petition 870250053177, dated 06 / 25 / 2025, pp. 44 / 63 2 / 20 conventional dose adjustment mechanism, the sphere may not be reset in the kinetic energy release process after the kinetic energy is stored, and because there are many components included, the reliability of the injector pen is reduced. SUMMARY

[006] The objective of the present application is to provide an injector pen and a dose adjustment mechanism for the injector pen. Through structural optimization, the smoothness of the ball's rolling in the dose adjustment mechanism can be ensured, so that the ball can be reset without problems, and the reliability and safety of the injector pen are improved.

[007] To solve the above technical problems, a dose adjustment mechanism for an injector pen is provided according to the embodiments of the present application. The dose adjustment mechanism includes a force rod, a cylinder, a ball, a sleeve, and a torsion spring. The cylinder is mounted outside the force rod, and a spiral channel extending along the direction of the axis of the force rod is formed between an inner wall of the cylinder and an outer wall of the force rod, and the ball can be rolled in the spiral channel. The cylinder and an upper pen holder of the injector pen are relatively fixed in a circumferential direction; an upper end of the torsion spring is relatively fixed to the upper pen holder and a lower end of the torsion spring is connected to the sleeve.The force rod rotates relative to the cylinder when an external force is applied to the force rod; the sleeve is connected in a limited way to the force rod in the circumferential direction, and the sleeve is configured for transmission cooperation with a transmission mechanism of the injector pen.

[008] In one embodiment, the sleeve includes a rod insertion portion, the power rod includes a socket portion extending along the axial direction, the rod insertion portion is inserted into the socket portion, an outer peripheral wall of the rod insertion portion has a flat portion in the direction Petition 870250053177, dated 06 / 25 / 2025, pages 45 / 63 3 / 20 circumferential and an inner wall of the socket portion orifice has a flat wall that cooperates with the flat portion.

[009] In one embodiment, the dose adjustment mechanism further includes an axial limiting structure between the force rod and the sleeve to limit the relative position of the force rod and the sleeve in the axial direction.

[010] In one embodiment, one of the force rod and sleeve has a convex portion extending in a radial direction, and the other of the force rod and sleeve has a concave portion, and the convex portion is configured to fit into the concave portion; the axial limiting structure includes the convex portion and the concave portion.

[011] In one embodiment, a lower end of the force rod has an extension portion that extends downward in the axial direction, the extension portion is provided with a concave portion, the sleeve includes an inner cylinder portion, an inner cylinder wall of the inner cylinder portion near an upper end is provided with a convex portion that extends inward in the radial direction.

[012] In one embodiment, an outer wall of the glove near the lower end is provided with several convex ribs that extend outward in the radial direction, and the various convex ribs are arranged along a circumferential direction of the glove to correct a degree of concentricity between the glove and the upper pen holder.

[013] In one embodiment, the dose adjustment mechanism further includes a rotary knob assembly, and a circumferential limiting structure is provided between the rotary knob assembly and the force rod, and the rotary knob assembly is configured to cause the force rod to rotate through the circumferential limiting structure.

[014] In one example, the force rod is configured to move relative to the cylinder towards a lower cap of the injector pen when an external force is applied to the force rod, so as to release a circumferential boundary with the rotary button assembly. Petition 870250053177, dated 06 / 25 / 2025, pages 46 / 63 4 / 20

[015] In one embodiment, the dose adjustment mechanism further includes a torsion spring support, and the torsion spring support is relatively fixed to the upper pen holder, and the cylinder is relatively fixed to the torsion spring support, the torsion spring support is connected to the upper end of the torsion spring.

[016] An injector pen is provided in accordance with an embodiment of the present application. The injector pen includes an upper pen holder and a dose adjustment mechanism installed in the upper pen holder, and the dose adjustment mechanism is any of the dose adjustment mechanisms described above.

[017] In one embodiment, the injection pen further includes a transmission mechanism, and the sleeve is configured to move downward in the axial direction relative to the upper pen holder to engage with a drive wheel of the transmission mechanism, or to move upward in the axial direction relative to the upper pen holder to disengage from the drive wheel; the sleeve is in a state of engagement with the drive wheel, and the sleeve is configured to cause the drive wheel to rotate; the drive wheel includes a cylindrical portion extending into the sleeve, and an outer peripheral wall of the cylindrical portion is provided with several convex ridges arranged in the circumferential direction, to correct the degree of concentricity of the drive wheel and the sleeve.

[018] In one embodiment, the drive wheel includes a base portion fixedly connected to a lower end of the cylindrical portion, and several projections that extend upward in the axial direction are arranged near an outer edge of the base portion, and the various projections are arranged in the circumferential direction to correct the degree of concentricity of the drive wheel and the upper pen holder.

[019] The structural arrangement of the injector pen's dose adjustment mechanism adopts a transmission mode in which the force rod, cylinder, and ball cooperate to achieve high transmission precision during the injector pen's dose adjustment process, thus ensuring the accuracy of the drug dose adjustment; at the same time, during the dose adjustment process, the force rod can rotate positively relative to the cylinder and, during the injection process Petition 870250053177, dated 06 / 25 / 2025, pp. 47 / 63 5 / 20 of the medication, the force rod can still rotate relative to the cylinder, that is, during the energy storage and release process of the torsion spring, the force rod can rotate relative to the cylinder, so that the ball rolls smoothly and is reliably reset, thus ensuring the accuracy of the dose adjustment and providing reliability and safety in the operation of the injector pen. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic structural diagram of an injector pen according to an embodiment of the present application; FIG. 2 is a schematic cross-sectional diagram of the injector pen shown in FIG. 1 in a first state; FIG. 3 is an enlarged partial diagram of a region where the upper pen holder assembly is located in FIG. 2; FIG. 4 is a schematic structural diagram of the combination of the force rod and the sleeve in a specific embodiment; FIG. 5 is a schematic cross-sectional diagram of the power rod and sleeve, shown in FIG. 4; FIG. 6 is a schematic structural diagram of the force rod of FIG. 4; FIG. 7 is a schematic structural diagram of the glove in FIG. 4; FIG. 8 is a schematic structural diagram of the drive wheel in a specific embodiment; FIG. 9 is an enlarged partial diagram of the corresponding part of the pressure mechanism and the dose adjustment mechanism when the injector pen shown in FIG. 1 is in the second state; FIG. 10 is an enlarged partial diagram of the corresponding part of the sleeve and drive wheel when the injector pen shown in FIG. 1 is in the second state.

[020] Reference numbers: Petition 870250053177, dated 06 / 25 / 2025, pp. 48 / 63 6 / 20 100: injector pen; 10: top pen holder assembly; 20: bottom pen cap assembly; 11: top pen holder; 111: display window; 12: button mechanism; 121: button assembly; 123: elastic resetting member; 13: dose adjustment mechanism; 131: rotary knob assembly; 1311: rotary knob; 1312: stop support; 13121: first internal toothed crown; 132: power rod; 1321: socket portion; 1322: extension portion; 1323: concave portion; 1324: first locking tooth; 133: cylinder; 134: sphere; 135: glove; 1351: stem insertion portion; 13511: flat portion; Petition 870250053177, dated 06 / 25 / 2025, pp. 49 / 63 7 / 20 1352: inner cylinder portion; 1353: outer cylinder portion; 1354: convex portion; 1355: convex rib; 1356: second inner toothed crown; 136: torsion spring; 137: torsion spring support; 138: dial; 14: transmission mechanism; 141: drive wheel; 1411: cylindrical portion; 1412: base portion; 1413: convex crest; 1414: protrusion; 1415: second locking tooth; 142: screw; 143: bottle holder lid; 21: bottom cap of a pen; 22: bottle holder; 23: cartridge bottle; 231: bottle retaining stopper. DETAILED DESCRIPTION OF THE MODALITIES

[021] An injector pen and a dose adjustment mechanism for the injector pen Petition 870250053177, dated 06 / 25 / 2025, pages 50 / 63 8 / 20 are supplied according to the embodiments of the present application. By optimizing the structure of the dose adjustment mechanism, the smoothness of the ball's rolling can be improved to ensure that the ball can be reset without problems.

[022] For ease of understanding and concise description, what follows is a description of the injector pen and of a dose adjustment mechanism of the injector pen, and the specific embodiment is described in detail with the injector pen shown in the attached figure as the object of description.

[023] In this application, the side on which the injector pen's push-button mechanism is located is defined as the top side. The injection end of the injector pen, or a side near the injection site when in use, is defined as the bottom side. The direction of the injector pen's length is defined as the axial direction; a side near the center of the injector pen is the inner side, and consequently, a side away from the center of the injector pen is the outer side. It may be understood that the use of directional words is merely for ease of description and understanding, and does not constitute a limitation to the scope of protection.

[024] With regard to FIGS. 1 to 3, FIG. 1 is a schematic structural diagram of the injector pen according to an embodiment of the present application; FIG. 2 is a schematic diagram of the cross-section of the injector pen shown in FIG. 1 in the first state; FIG. 3 is an enlarged partial view of the region where the upper pen holder assembly is located in FIG. 2.

[025] In one example, the injector pen 100 includes an upper pen holder assembly 10 and a lower pen cap assembly 20.

[026] The upper pen holder assembly 10 includes an upper pen holder 11, a button mechanism 12, a dose adjustment mechanism 13 and a transmission mechanism 14. The upper pen holder 11 serves as the mounting base for the button mechanism 12, the dose adjustment mechanism 13 and the transmission mechanism 14.

[027] The pen bottom cap assembly 20 includes a pen bottom cap 21, a vial holder 22 and a cartridge vial 23. The vial holder 22 is inserted Petition 870250053177, dated 06 / 25 / 2025, pages 51 / 63 9 / 20 on the lower cap of pen 21 to install the cartridge bottle 23. The upper end of the bottle holder 22 extends outward from the lower cap of pen 21 to be connected to the upper pen holder 11. The lower end of the upper pen holder 11 is mounted externally on the upper end of the bottle holder 22.

[028] The transmission mechanism 14 in the upper pen holder 11 can cooperate with a vial retention stopper 231 of the cartridge vial 23. The dose adjustment mechanism 13 can provide motive force to the transmission mechanism 14, so that the transmission mechanism 14 pushes the vial retention stopper 231 down to perform the injection of the medication.

[029] It should be noted that cartridge vial 23 is a container for storing medication that is not actually part of the injector pen 100, but is used in conjunction with the injector pen 100. In application, cartridge vial 23 is a replaceable component.

[030] In one embodiment, the dose adjustment mechanism 13 of the injector pen 100 includes a force rod 132, a cylinder 133, a sphere 134, a sleeve 135 and a torsion spring 136.

[031] Cylinder 133 is mounted outside of force rod 132, and a spiral channel extending along the axial direction of force rod 132 is formed between the inner wall of cylinder 133 and the outer wall of force rod 132, and sphere 134 can be rolled in the spiral channel. Among them, the axial direction of force rod 132 is consistent with the axial direction of the injector pen 100.

[032] Cylinder 133 is relatively fixed to the upper pen holder 11 in the circumferential direction; the upper end of the torsion spring 136 is relatively fixed to the upper pen holder 11, and the lower end of the torsion spring 136 is connected to the sleeve 135; the force rod 132 is connected in a limited way to the sleeve 135 in the circumferential direction. In other words, the force rod 132 and the sleeve 135 may not rotate relative to each other, but they may rotate together; the sleeve 135 and the transmission mechanism 14 may alternate between a transmission engagement state and a transmission separation state. In other words, when Petition 870250053177, dated 06 / 25 / 2025, pp. 52-63 When sleeve 135 and transmission mechanism 14 are in a transmission engagement state, power transmission can be performed between the two, and when sleeve 135 and transmission mechanism 14 are in a transmission separation state, power transmission cannot be performed between the two.

[033] Under the action of an external force, the force rod 132 can rotate relative to the cylinder 133 and cause the sleeve 135 to rotate along with it.

[034] During operation, an external force may be applied to the force rod. 132 to rotate the force rod 132 in the direction of the injection dose adjustment. When the force rod 132 rotates, the sleeve 135 can be actuated to rotate along with it, but the cylinder 133 does not move. In this way, the ball 134 can roll in one direction along the spiral channel between the force rod 132 and the cylinder 133. As the upper end of the torsion spring 136 is relatively fixed to the upper pen holder 11 and the lower end is connected to the sleeve 135, the lower end of the torsion spring 136 rotates with the sleeve 135 to store energy. After rotating to the required injection dose position, the force rod 132, the sleeve 135, and the torsion spring 136 can be held in that position; Next, the stored energy of the torsion spring 136 can be released by the operation, i.e., the position lock of the force rod 132, the sleeve 135 and the torsion spring 136 is released, and the sleeve 135 and the transmission mechanism 14 are in a transmission engagement state.With the release of the stored energy from the torsion spring 136, the force rod 132 and the sleeve 135 rotate in opposite directions, and the driving force is transmitted to the transmission mechanism 14 through the engagement of the sleeve 135 and the transmission mechanism 14, thus pushing the vial retaining stopper 231 downwards to perform the injection of the medication. When the force rod 132 and the sleeve 135 rotate in opposite directions, the cylinder 133 does not move, so that the ball 134 can roll in the opposite direction and be reset.

[035] According to the operation above, the degree of rotation of the sleeve 135 actuated by the force rod 132 determines the stored energy of the torsion spring 136, and the stored energy of the torsion spring 136 is related to the pushing stroke of the Petition 870250053177, dated 06 / 25 / 2025, pages 53 / 63 11 / 20 vial retention stopper 231 downwards, i.e., related to the injection dose of the medication.

[036] It can be understood that the reverse rotation of the force rod 132 and the sleeve 135 refers to rotation in the opposite direction to the previously mentioned rotation in the direction of injection dose adjustment, and the reverse rolling of the sphere 134 is also rolling in the opposite direction to the previous direction.

[037] Here, rotation in the direction of the dose adjustment is defined as positive rotation and, correspondingly, rotation in the opposite direction to the dose adjustment is reverse rotation.

[038] With the above scheme, the injector pen 100 adopts a transmission mode in which the force rod 132, the cylinder 133 and the ball 134 cooperate in the dose adjustment process, and the transmission precision is high, which can ensure the accuracy of the drug dose adjustment; at the same time, in the dose adjustment process, the force rod 132 can rotate forward relative to the cylinder 133 and, in the drug injection process, the force rod 132 can still rotate relative to the cylinder 133, so that the ball 134 rolls smoothly and is reliably reset, thus ensuring the accuracy of the dose adjustment and providing the reliability and safety of the injector pen 100 operation.

[039] In one embodiment, the dose adjustment mechanism 13 further includes a rotary knob assembly 131, and a circumferential limiting structure is provided between the rotary knob assembly 131 and the force rod 132. When the rotary knob assembly 131 rotates, the force rod 132 can be actuated to rotate through the circumferential limiting structure.

[040] In a specific implementation, the rotary button assembly 131 includes a rotary button 1311 and a stop support 1312, wherein the rotary button 1311 and the stop support 1312 are connected in a circumferential limiting manner, and a portion of the stop support 1312 is mounted internally in the rotary button 1311, and the lower end of the rotary button 1311 is rotatably mounted outside the upper pen holder 11. Petition 870250053177, dated 06 / 25 / 2025, pages 54 / 63 12 / 20

[041] In one example, the force rod 132 passes through the stop support 1312, and a circumferential limiting structure is provided between the force rod 132 and the stop support 1312.

[042] Specifically, the circumferential limiting structure between the stop support 1312 and the force rod 132 includes a first internal toothed crown 13121 in the stop support 1312 and a first locking tooth 1324 (marked in figs. 4 to 6) on the outer wall of the force rod 131. Under normal conditions, the first locking tooth 1324 of the force rod 131 can be fitted into the tooth groove of the first internal toothed crown 13121, thus limiting the circumferential position of the force rod 131 and the stop support 1312, so that the stop support 1312 can cause the force rod 132 to rotate together.

[043] In the example shown, the force rod 131 is provided with four first locking teeth 1324 along the circumferential direction. In actual applications, the number of first locking teeth 1324 of the force rod 131 may be set to other numbers, such as two, three or more. It is best to arrange the multiple first locking teeth 1324 evenly along the circumferential direction to balance the force between the force rod 131 and the stop support 1312.

[044] In other implementations, a circumferential limiting structure may also be provided between the force rod 132 and the rotary knob 1311.

[045] In the application, the user can rotate the rotary knob 1311 to cause the stop support 1312 and the force rod 132 to rotate together to adjust the dose.

[046] In one example, the dose adjustment mechanism 13 further includes a torsion spring support 137, which is relatively fixed to the upper pen holder 11, and the cylinder 133 is encased by the torsion spring support 137. The cylinder 133 can be relatively fixed to the upper pen holder 11 by means of relative fixation with the torsion spring support 137.

[047] The relative fastening method of the torsion spring support 137 and the upper pen holder 11 and the relative fastening method of the cylinder 133 and the spring support Petition 870250053177, dated 06 / 25 / 2025, pages 55 / 63 13 / 20 torsion 137 can adopt the interlocking structure method, which is convenient for disassembly and assembly and facilitates maintenance.

[048] The upper end of the torsion spring 136 mentioned above can be specifically connected to the torsion spring support 137.

[049] In a specific implementation, a limiting structure is provided between the rotary button assembly 131 and the torsion spring support 137, and the limiting structure is arranged so that the rotary button assembly 131 can only rotate in one direction relative to the torsion spring support 137, but cannot rotate in the reverse direction. In the structural configuration of the injector pen 100, the rotary button assembly 131 can rotate forward relative to the torsion spring support 137, but cannot rotate in the reverse direction. In this way, after the rotary button assembly 131 actuates the force rod 132 to rotate forward to the position where the dose needs to be adjusted, the force rod 132, the sleeve 135 and the torsion spring 136 can be held in that position.

[050] In one example, the limiting structure between the rotary knob assembly 131 and the torsion spring support 137 can be a one-way locking wheel matching structure.

[051] In one embodiment, the force rod 132 can move relative to the cylinder 133 in the direction of the lower pen cap 21 of the injector pen 100 when an external force is applied to the force rod 132, so as to release the circumferential boundary between the force rod 132 and the rotary button assembly 131. In other words, the force rod 132 can move downwards relative to the upper pen holder 11 when the external force is applied to the force rod 132, so as to release itself from the circumferential boundary with the rotary button assembly 131 and further release the energy stored in the torsion spring 136. It can be understood that, after the force rod 132 is disengaged from the circumferential boundary with the rotary button assembly 131, the force rod 132 is not restrained by the rotary button assembly 131, and the sleeve 135 and the spring of Torsion springs 136 are no longer restricted. The energy stored in the torsion spring 136 can be released, causing the... Petition 870250053177, dated 06 / 25 / 2025, pages 56 / 63 14 / 20 sleeve 135 and the power rod 132 rotate in opposite directions.

[052] Specifically, when the force rod 132 moves down in the axial direction, the first locking tooth 1324 moves down in the same proportion, and the axial position of the stop support 1312 of the rotary button assembly 131 remains unchanged, so that the first locking tooth 1324 disengages from the first inner toothed crown 13121, thus releasing the circumferential boundary between the force rod 132 and the rotary button assembly 131.

[053] In one example, the sleeve 135 can move downward in the axial direction relative to the upper pen holder 11 to engage with the transmission mechanism 14 and obtain force transmission, or move upward in the axial direction relative to the upper pen holder 11 to separate from the transmission mechanism 14 and obtain force interruption.

[054] In a specific implementation, the sleeve 135 and the force rod 132 are constrained and connected in the axial direction, so that they move together along the axial direction when an external force is applied to the sleeve 135 and the force rod 132.

[055] In a specific implementation, the button mechanism 12 of the injector pen 100 mentioned earlier serves as a structure that can apply a downward force to the force rod 132.

[056] The button mechanism 12 includes a button assembly 121 and a reset elastic member 123, and the button assembly 121 is limited and connected to the force rod 132 along the axial direction.

[057] During operation, the button mechanism 12 is pressed down, and the button mechanism 12 can cause the force rod 132 and the sleeve 135 to move together downwards, releasing the circumferential limit connection between the force rod 132 and the rotating button assembly 131, and causing the sleeve 135 to engage with the transmission mechanism 14. In this way, the stored energy of the torsion spring 136 can be released to cause the sleeve 135 and the force rod 132 to rotate in the opposite direction. At this moment, the sleeve 135 is engaged with the transmission mechanism 14, and the sleeve 135 can transmit force to the transmission mechanism. Petition 870250053177, dated 06 / 25 / 2025, pages 57 / 63 15 / 20 when rotated, in order to push the bottle retaining stopper 231. After the button assembly 121 is pressed, the reset elastic member 123 stores energy, which is used to reset the button assembly 121 after the pressure force on the button mechanism 12 is canceled.

[058] In terms of layout, the button mechanism 12, the dose adjustment mechanism 13 and the transmission mechanism 14 are arranged approximately from top to bottom; the main body of the sleeve 135 of the dose adjustment mechanism 13 is located below the force rod 132.

[059] In one embodiment, a dial 138 is mounted outside the glove 135, and the glove 135 and the dial 138 are connected in a limited circumferential direction. The outer side of the dial 138 is the upper pen holder 11, and the upper pen holder 11 has a display window 111. When the dose is adjusted, the dial 138 can rotate with the glove 135, so that the user can determine the adjusted dose by means of the scale on the dial 138 displayed in the display window 111.

[060] With regard to FIGS. 4 to 7, FIG. 4 is a schematic structural diagram of the correspondence between the force rod and the sleeve in a specific embodiment; FIG. 5 is a schematic cross-sectional diagram of the force rod and sleeve shown in FIG. 4; FIG. 6 is a schematic structural diagram of the force rod of FIG. 4; FIG. 7 is a schematic structural diagram of the sleeve of FIG. 4.

[061] In one example, the force rod 132 has a socket portion 1321 that extends along the axial direction, and the sleeve 135 includes a rod insertion portion 1351, which is inserted into the socket portion 1321 of the force rod 132. The outer peripheral wall of the rod insertion portion 1351 has a flat portion 13511 in the circumferential direction, and the inner hole wall of the socket portion 1321 has a flat wall that corresponds to the flat portion 13511. Thus, after the rod insertion portion 1351 of the sleeve 135 is inserted into the socket portion 1321 of the force rod 132, the force rod 132 can cause the Petition 870250053177, dated 06 / 25 / 2025, pages 58 / 63 16 / 20 sleeve 135 rotate together under the action of the mutually corresponding flat portion 13511 and flat wall. Apparently, the flat portion 13511 and the flat wall constitute a circumferential boundary connection structure between the force rod 132 and the sleeve 135.

[062] In the specific implementation, the cross-sections of the rod insertion portion 1351 and the mutually combined socket portion 1321 may be non-circular structures, such as rectangles, squares, triangles or polygons; the cross-sections may also have other irregular shapes with planar structures.

[063] The axial limiting structure between the force rod 12 and the sleeve 135 can have various forms. The following method is relatively simple and reliable.

[064] A convex portion 1354 extending inward in the axial direction is provided in the sleeve 135, and a concave portion 1323 cooperating with the convex portion 1354 is provided in the force rod 132. After the rod insertion portion 1351 of the sleeve 135 is inserted into the socket portion 1321 of the force rod 132, the convex portion 1354 of the sleeve 135 can engage with the concave portion 1323 of the force rod 132. As shown in FIG. 5, the sleeve 135 and the force rod 12 along the axial direction are constrained by the engagement of the convex portion 1354 and the concave portion 1323.

[065] In a specific implementation, the lower end of the force rod 132 near the sleeve 135 has an extension portion 1322 that extends downwards along the axial direction, and the concave portion 1323 is formed on the side wall of the extension portion 1322 facing the sleeve 135. The concave portion 1323 may be in the form of a groove or a hole.

[066] The sleeve 135 includes an inner cylinder portion 1352 connected to the rod insertion portion 1351, and the inner cylinder wall of the inner cylinder portion 1352, near the top, has the convex portion 1354 mentioned above. After assembly, the extension portion 1322 of the power rod 132 can extend to the inner cylinder portion 1352. The lower end of the Petition 870250053177, dated 06 / 25 / 2025, pages 59 / 63 17 / 20 rod insertion portion 1351 is located partially in the inner cylinder portion 1352 to facilitate engagement of the convex portion 1354 and the concave portion 1323.

[067] In other implementations, the convex portion 1354 and the concave portion 1323 mentioned above can be placed in reverse, that is, the convex portion 1354 is placed on the power rod 132 and the concave portion 1323 is placed on the sleeve 135.

[068] The sleeve 135 further includes an outer cylinder portion 1353 which is mounted outside the inner cylinder portion 1352. The lower ends of the inner cylinder portion 1352 and the outer cylinder portion 1353 are connected together, and a space to accommodate the aforementioned torsion spring 136 is formed between the inner cylinder portion 1352 and the outer cylinder portion 1353. A hook hole may be provided at the lower end of the sleeve 135 to facilitate engagement and connection with the lower end of the torsion spring 136.

[069] Specifically, more than two groups of mutually corresponding concave portions 1323 and convex portions 1354 of the force rod 132 and sleeve 135 can be provided, uniformly arranged along the circumferential direction of the force rod 132, so that the connection between the force rod 132 and the sleeve 135 is uniformly tensioned to prevent deflection. The figure shows the structure of two groups of concave portions 1323 and convex portions 1354.

[070] In a specific implementation, several convex ribs 1355 extending outwards along the radial direction are provided on the outer wall of the sleeve 135 near the lower end, and several convex ribs 1355 are arranged along the circumferential direction of the sleeve 135 to correct the degree of concentricity of the sleeve 135 and the upper pen holder 11. In this way, deflection of the sleeve 135 can be avoided to affect the transmission effect with the transmission mechanism 14.

[071] In one example, the transmission mechanism 14 of the injector pen 100 includes a drive wheel 141, a screw 142 and a vial holder cap 143. The wheel Petition 870250053177, dated 06 / 25 / 2025, pages 60 / 63 The 18 / 20 drive wheel 141 can be engaged or disengaged with the sleeve 135, the screw 142 is circumferentially limited by the drive wheel 141 and is threaded onto the bottle holder cover 143, and the lower end of the screw 142 passes through the bottle holder cover 143 and may abut the bottle retaining stopper 231. Generally, there is a gasket between the screw 142 and the bottle retaining stopper 231.

[072] A coupling structure is provided between the drive wheel 141 and the sleeve. 135. The coupling structure can cause the sleeve 135 and the drive wheel 141 to engage when the sleeve 135 moves downwards in the axial direction, so that the sleeve 135 can cause the drive wheel 141 to rotate together. When the sleeve 135 moves upwards in the axial direction, the sleeve 135 and the drive wheel 141 can be separated, so that the rotation of the sleeve 135 does not affect the drive wheel 141.

[073] Referring to FIG. 8, FIG. 8 is a schematic structural diagram of the drive wheel in a specific embodiment.

[074] In a specific implementation, the drive wheel 141 includes a cylindrical portion 1411 that extends to the sleeve 135, and the outer peripheral wall of the cylindrical portion 1411 is provided with several convex ridges 1413 arranged in the circumferential direction to correct the degree of concentricity of the drive wheel 141 and the sleeve 135. This can help ensure the engagement and separation of the sleeve 135 and the drive wheel 141, prevent the two from becoming stuck, and improve the reliability of the injector pen 100 operation.

[075] The drive wheel 141 further includes a base portion 1412 fixed to the lower end of the cylindrical portion 1411. The base portion 1412 is provided with several protrusions 1414 that project upwards in the axial direction near the outer edge. The various protrusions 1414 are arranged circumferentially to correct the degree of concentricity of the drive wheel 141 and the upper pen holder 11. In this way, it is beneficial to improve the reliability of the transmission cooperation between the drive wheel 141 and the sleeve 135.

[076] In the application, the multiple convex ridges 1413 mentioned above can be arranged uniformly in the circumferential direction, and the Petition 870250053177, dated 06 / 25 / 2025, pages 61 / 63 19 / 20 multiple protrusions 1414 mentioned earlier are also arranged uniformly in the circumferential direction, so that the corresponding components are tensioned more uniformly and more conducive to correcting the degree of concentricity.

[077] In a specific implementation, the lower end of the sleeve 135 has a second internal toothed ring 1356, and the drive wheel 141 is provided with a second locking tooth 1415. When the sleeve 135 moves downwards in the axial direction, the second locking tooth 1415 on the drive wheel 141 can be fitted into the tooth groove of the second internal toothed ring 1356, thus engaging the drive wheel 141 and the sleeve 135, so that the sleeve 135 can cause the drive wheel 141 to rotate together. When sleeve 135 moves upward in the axial direction, the second inner toothed crown 1356 is disengaged from the second locking tooth 1415 of the drive wheel 141, so that the drive wheel 141 and sleeve 135 are separated, and the drive wheel 141 does not rotate with sleeve 135.

[078] In a specific implementation, the cylinder cavity of the inner cylinder portion 1352 of the sleeve 135 serves as a space to accommodate the screw 142. In other words, the bottom of the sleeve 135 is an opening structure that penetrates the cylinder cavity of the inner cylinder portion 1352.

[079] When the dose is adjusted by turning the rotary knob assembly 131 and the knob assembly 121 is pressed, the force rod 132 and the sleeve 135 move downward along the axial direction, the force rod 132 is separated from the circumferential limit of the rotary knob assembly 131 and the sleeve 135 is engaged in the drive wheel 141. With the release of the stored energy of the torsion spring 136, the force rod 132 and the sleeve 135 rotate together, causing the drive wheel 141 to rotate. When the drive wheel 141 rotates, it causes the circumferentially limited screw 142 to rotate along with it, and the screw 142 is threaded into the vial holder cap 143. Under the action of the thread, the screw 142 moves downward along the axial direction, pushing the vial retaining stopper 231 down to obtain the injection of the drug. Petition 870250053177, dated 06 / 25 / 2025, pages 62 / 63 20 / 20

[080] Comparing FIGS. 2 and 3 with FIGS. 9 and 10, in FIGS. 2 and 3, the injector pen 100 is in a first state in which the force rod 132 and the rotary button assembly 131 are circumferentially constrained, and the sleeve 135 and the drive wheel 141 are separated. Figure 9 shows the second state in which the circumferential constraint of the force rod 132 and the rotary button assembly 131 is released after the button assembly 121 is pressed. It can be seen in the figure that the first locking tooth 1324 of the power rod 132 is separated from the first inner toothed crown 13121 of the rotary button assembly 131. Figure 10 shows that the sleeve 135 and the drive wheel 141 are in an engaged state after the button assembly 121 is pressed.

[081] The specific structure and connection of the relevant parts of the lower cap assembly 20 of the injector pen 100 are not the core of the invention of the present application and can be understood based on conventional technology, and will not be described in detail here.

[082] This article uses specific embodiments to explain the principles and methods of implementation of the present application. The description of the embodiments above is intended only to facilitate understanding of the method and central idea of ​​the present application. It should be noted that, for a person ordinarily skilled in the art, various improvements and modifications can be made to the present application without departing from the principles of the present application, and such improvements and modifications fall within the scope of protection of the claims of the present application. Petition 870250053177, dated 06 / 25 / 2025, page 63 / 63

Claims

1 / 3 CLAIMS 1. A dose adjustment mechanism for an injector pen, characterized in that it comprises: a force rod, a cylinder, a ball, a sleeve, and a torsion spring; wherein the cylinder is mounted outside the force rod, a spiral channel extending along an axis direction of the force rod is formed between an inner wall of the cylinder and an outer wall of the force rod, and the ball can be rolled in the spiral channel; the cylinder and an upper pen holder of the injector pen are relatively fixed in a circumferential direction; an upper end of the torsion spring is relatively fixed to the upper pen holder and a lower end of the torsion spring is connected to the sleeve; the force rod is rotatable relative to the cylinder under the action of an external force;The sleeve is connected in a limited way to the force rod in the circumferential direction, and the sleeve is configured for transmission cooperation with a transmission mechanism of the injector pen; the sleeve comprises a rod insertion portion, the force rod comprises a socket portion that extends along the axial direction, the rod insertion portion is inserted into the socket portion, an outer peripheral wall of the rod insertion portion has a flat portion in the circumferential direction and an inner orifice wall of the socket portion has a flat wall that cooperates with the flat portion; the dose adjustment mechanism also comprises an axial limiting structure between the force rod and the sleeve, so as to limit the relative position of the force rod and the sleeve in the axial direction.

2. Dose adjustment mechanism according to claim 1, characterized in that one of the force rod and the sleeve has a convex portion extending in a radial direction, and the other of the force rod and the sleeve has a concave portion, and the convex portion is configured to fit into the concave portion; the axial limiting structure comprises the convex portion and the concave portion.

3. Dose adjustment mechanism according to claim 2, characterized in that a lower end of the force rod has an extension portion that extends downwards in the axial direction, the extension portion is provided with a concave portion, the sleeve comprises an inner sleeve portion, an inner cylinder wall of the inner cylinder portion near an upper end is provided with a convex portion that extends inwards in the radial direction.

4. Dose adjustment mechanism according to any one of claims 1 to 3, characterized in that an outer wall of the glove near the lower end is provided with a plurality of convex ribs extending outwards in the radial direction, and the plurality of convex ribs is arranged along a circumferential direction of the glove to correct a degree of concentricity between the glove and the upper pen holder.

5. Dose adjustment mechanism according to any one of claims 1 to 3, characterized in that the suit further comprises a rotary knob assembly, wherein a circumferential limiting structure is provided between the rotary knob assembly and the force rod, and the rotary knob assembly is configured to cause the force rod to rotate through the circumferential limiting structure.

6. Dose adjustment mechanism according to claim 5, characterized in that the force rod is configured to move relative to the cylinder towards a lower cap of the injector pen under the action of an external force, to release a circumferential limit with the rotary button assembly.

7. Dose adjustment mechanism according to any one of claims 1 to 3, characterized in that it further comprises a torsion spring support, wherein the torsion spring support is relatively fixed to the upper pen holder and the cylinder is relatively fixed to the torsion spring support, Petition 870250053177, dated 06 / 25 / 2025, page 33 / 63 3 / 3 wherein the torsion spring support is connected to the upper end of the torsion spring.

8. Injector pen, characterized in that it comprises: an upper pen holder and a dose adjustment mechanism installed in the upper pen holder, wherein the dose adjustment mechanism is the dose adjustment mechanism as defined in any one of claims 1 to 7.

9. Injection pen according to claim 8, characterized in that it further comprises a transmission mechanism, wherein the sleeve is configured to move downwards in the axial direction relative to the upper pen holder to engage with a drive wheel of the transmission mechanism, or to move upwards in the axial direction relative to the upper pen holder to disengage from the drive wheel; when the sleeve is in a state of engagement with the drive wheel, the sleeve is configured to cause the drive wheel to rotate; the drive wheel comprises a cylindrical portion extending into the sleeve, and an outer peripheral wall of the cylindrical portion is provided with a plurality of convex ridges arranged in the circumferential direction so as to correct the degree of concentricity of the drive wheel and the sleeve.

10. Injection pen according to claim 9, characterized in that the drive wheel comprises a base portion fixedly connected to a lower end of the cylindrical portion, and a plurality of upward projections in the axial direction are arranged near an outer edge of the base portion, and the plurality of projections are arranged in the circumferential direction to correct the degree of concentricity of the drive wheel and the upper pen holder. Petition 870250053177, dated 06 / 25 / 2025, p. 34 / 63

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