INJECTOR PEN AND DOSE ADJUSTMENT MECHANISM THEREOF

Abstract

An injector pen and a dose adjustment mechanism of the injector pen are provided. The dose adjustment mechanism (13), comprising: a cylinder (133) mounted outside a drive rod (132), a spiral channel extending along an axis direction of the drive rod (132) and formed between an inner wall of the cylinder (133) and an outer wall of the drive rod (132), a ball (134) being rollable in the spiral channel; the cylinder (133) and an upper pen holder (11) of the injector pen (100) being relatively fixed in a circumferential direction; the drive rod (132) being rotatable relative to the cylinder (133) under the action of an external force; a sleeve (135) being limitedly connected with the drive rod (132) in the circumferential direction, and configured to provide transmission cooperation with a transmission mechanism (14) of the injector pen (100).

Description

Title of the invention: INJECTOR PEN AND DOSE ADJUSTMENT MECHANISM THEREOF Technical field

[0001] The present invention relates to the technical field of medical devices and, in particular, to an injector pen and a dose adjustment mechanism thereof. STATE OF THE PRIOR ART

[0002] Insulin injection therapy is the most commonly used treatment method in clinical work, which gives rise to 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 injecting insulin, injector pens can also be used to inject other medications.

[0003] In the prior art, an injector pen includes an upper pen holder assembly and a lower pen cap. The upper pen holder assembly includes a 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 operating the dose adjustment mechanism. Upon a pressing operation of a button mechanism, the kinetic energy stored in the dose adjustment mechanism can be released, and the plunger of the cartridge can be pushed through the transmission mechanism to achieve a drug injection.

[0004] In order to achieve precise control of drug injection, the dose adjustment mechanism generally adopts the principle of ball screw. However, in the conventional dose adjustment mechanism, the ball may not be reset in the process of releasing the kinetic energy after the kinetic energy is stored, and since too many components are included, the reliability of the injection pen is reduced. Statement of the invention

[0005] The purpose of the present invention is to provide an injector pen and a dose adjustment mechanism of the injector pen. By means of structural optimization, the smooth rolling of the ball in the dose adjustment mechanism can be ensured, so that the ball can be reset easily and the reliability and safety of the injector pen are improved.

[0006] To solve the above technical problems, a dose adjustment mechanism of an injector pen is provided according to embodiments of the present invention. The dose adjustment mechanism includes a driving rod, a cylinder, a ball, a sleeve, and a torsion spring. The cylinder is mounted outside the driving rod, and a spiral channel extending along an axis direction of the driving rod is formed between an inner wall of the cylinder and an outer wall of the driving rod, and the ball can roll 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 driving rod can rotate relative to the cylinder when an external force is exerted on the driving rod; the sleeve is limitedly connected with the driving rod in the circumferential direction, and the sleeve is configured to provide transmission cooperation with a transmission mechanism of the injector pen.

[0007] In one embodiment, the sleeve includes a rod insertion portion, the drive 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 circumferential direction, and an inner hole wall of the socket portion has a flat wall that cooperates with the flat portion.

[0008] In one embodiment, the dose adjustment mechanism further includes an axial limiting structure between the drive rod and the sleeve for limiting a relative position of the drive rod and the sleeve in the axial direction.

[0009] In one embodiment, the drive rod or the sleeve is provided with a convex portion extending in a radial direction, and the other of the drive rod or the sleeve is provided with a concave portion, and the convex portion is configured to snap into the concave portion; the axial limiting structure includes the convex portion and the concave portion.

[0010] In one embodiment, a bottom end of the drive rod has an extension portion extending downward in the axial direction, the extension portion is provided with the concave portion, the sleeve includes an inner cylinder portion, an inner cylinder wall of the inner cylinder portion near a top end is provided with the convex portion extending inward in the radial direction.

[0011] In one embodiment, an outer wall of the sleeve near a bottom end is provided with multiple convex ribs extending outward in the radial direction, and the multiple convex ribs are arranged along a circumferential direction of the sleeve to correct a degree of concentricity between the sleeve and the upper pen holder.

[0012] In one embodiment, the dose adjustment mechanism further includes a thumbwheel assembly, and a circumferential limiting structure is provided between the thumbwheel assembly and the drive rod, and the thumbwheel assembly is configured to cause the drive rod to rotate by the circumferential limiting structure.

[0013] In one embodiment, the drive rod is configured to move relative to the barrel toward a lower cap of the injector pen when an external force is exerted on the drive rod, so as to release a circumferential boundary with the thumbwheel assembly.

[0014] In one embodiment, the dose adjustment mechanism further includes a torsion spring holder, and the torsion spring holder is fixed relative to the upper pen holder, and the barrel is fixed relative to the torsion spring holder, the torsion spring holder is connected to the upper end of the torsion spring.

[0015] An injector pen is provided according to one embodiment of the present invention. The injector pen includes an upper pen holder and a dose adjustment mechanism installed on the upper pen holder, and the dose adjustment mechanism is any one of the dose adjustment mechanisms described above.

[0016] In one embodiment, the injector 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 move upward in the axial direction relative to the upper pen holder to separate from the drive wheel; the sleeve is in an engaged state with the drive wheel, and the sleeve is configured to drive 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 multiple convex ridges arranged in the circumferential direction to correct the concentricity degree of the drive wheel and the sleeve.

[0017] In one embodiment, the drive wheel includes a base portion fixedly connected to a lower end of the cylindrical portion and multiple projections projecting upward in the axial direction are arranged near an outer edge of the base portion, and the multiple projections are arranged in the circumferential direction to correct the degree of concentricity of the drive wheel and the upper pen holder.

[0018] The structural arrangement of the dose adjustment mechanism of the injector pen adopts a transmission mode in which the drive rod, the cylinder and the ball cooperate to achieve high transmission accuracy during the dose adjustment process of the injector pen, thereby ensuring the adjustment accuracy of the drug dose; at the same time, during the dose adjustment process, the drive rod can rotate positively relative to the cylinder, and during the drug injection process, the drive rod can further rotate relative to the cylinder, that is, during the process of storing energy and releasing the stored energy of the torsion spring, the drive rod can rotate relative to the cylinder so that the ball rolls smoothly and resets reliably, thereby ensuring the accuracy of dose adjustment and providing reliability and safety to the operation of the injection pen. Brief description of the drawings

[0019] [Fig.l] is a structural schematic diagram of an injector pen according to one embodiment of the present invention.

[0020] [Fig.2] is a schematic sectional diagram of the injector pen illustrated [Fig.l] in a first state.

[0021] [Fig.3] is a partial enlarged diagram of a region where the upper pen holder assembly is located [Fig.2].

[0022] [Fig.4] is a structural schematic diagram of the correspondence of the drive rod and the sleeve in a specific embodiment.

[0023] [Fig.5] is a schematic sectional diagram of the drive rod and sleeve shown in [Fig.4].

[0024] [Fig.6] is a structural schematic diagram of the drive rod in [Fig.4],

[0025] [Fig.7] is a structural schematic diagram of the sleeve in [Fig.4].

[0026] [Fig.8] is a structural schematic diagram of the drive wheel in a specific embodiment.

[0027] [Fig.9] is a partial enlarged diagram of the corresponding part of the pressure mechanism and the dose adjustment mechanism when the injector pen illustrated [Fig.l] is in the second state.

[0028] [Fig. 10] is a partial enlarged diagram of the corresponding portion of the sleeve and the drive wheel when the injector pen illustrated [Fig.l] is in the second state.

[0029] Reference numbers:

[0030] 100: Injector pen 10: Upper pen holder assembly 20: Cap assembly lower pen

[0031] 11: Upper pen holder 111: Display window 12: Button mechanism

[0032] 121: button assembly 123: elastic return element 13: adjustment mechanism of dose

[0033] 131: wheel assembly 1311: wheel 1312: stop support

[0034] 13121: first internal toothed crown 132: drive rod 1321: part socket

[0035] 1322: extension part 1323: concave part 1324: first locking tooth

[0036] 133: cylinder 134: ball 135: sleeve

[0037] 1351: rod insertion part 13511: flat part 1352: internal cylinder part

[0038] 1353: external cylinder part 1354: convex part 1355: convex rib

[0039] 1356: second internal toothed crown 136: torsion spring 137: support of torsion spring

[0040] 138: dial 14: transmission mechanism 141: drive wheel

[0041] 1411: cylindrical part 1412: base part 1413: convex edge

[0042] 1414: projection 1415: second locking tooth 142: screw

[0043] 143: bottle holder cover 21: lower pen cap 22: bottle holder

[0044] 23: cartridge bottle 231: bottle cap DETAILED PRESENTATION OF IMPLEMENTATION METHODS

[0045] An injector pen and a dose adjustment mechanism of the injector pen are provided according to embodiments of the present invention. By optimizing the structure of the dose adjustment mechanism, the smooth rolling of the ball can be improved to ensure that the ball can be reset easily.

[0046] For ease of understanding and concise description, hereinafter a description of the injector pen and a dose adjustment mechanism of the injector pen is given, and the specific embodiment is described in detail with the injector pen illustrated in the attached figure as the object of the description.

[0047] In the present invention, a side where the button mechanism of the injector pen is located is defined as the upper side. Therefore, the injection end of the injector pen or a side close to the injection site when in use is defined as the lower side. The length direction of the injector pen is defined as the axial direction, a side close to the center of the injector pen is the inner side, and therefore, a side opposite the center of the injector pen is the outer side. It can be understood that the use of directional terms is only for ease of description and understanding, without constituting a limitation to the scope of protection.

[0048] Referring to [Fig.l] to [Fig.3], [Fig.l] is a structural schematic diagram of the injector pen according to one embodiment of the present invention; [Fig.2] is a sectional schematic diagram of the injector pen shown [Fig.l] in the first state; [Fig.3] is a partial enlarged view of the region where the upper pen holder assembly is located [Fig.2].

[0049] In one embodiment, the injector pen 100 includes an upper pen holder assembly 10 and a lower pen cap assembly 20.

[0050] 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 an installation base for the button mechanism 12, the dose adjustment mechanism 13, and the transmission mechanism 14.

[0051] The lower pen cap assembly 20 includes a lower pen cap 21, a vial holder 22, and a cartridge vial 23. The vial holder 22 is inserted into the lower pen cap 21 to install the cartridge vial 23. The upper end of the vial holder 22 extends out of the lower pen cap 21 to be connected to the upper pen holder 11. The lower end of the upper pen holder 11 is externally mounted on the upper end of the vial holder 22.

[0052] The transmission mechanism 14 in the upper pen holder 11 can cooperate with a bottle cap 231 of the cartridge bottle 23. The dose adjustment mechanism 13 can provide a driving force to the transmission mechanism 14, so that the transmission mechanism 14 pushes the bottle cap 231 downward to achieve drug injection.

[0053] It should be emphasized that the cartridge bottle 23 is a container for storing medications, which is not actually part of the injector pen 100, but is used in conjunction with the injector pen 100. In practice, the cartridge bottle 23 is a replaceable component.

[0054] In one embodiment, the dose adjustment mechanism 13 of the injector pen 100 includes a drive rod 132, a cylinder 133, a ball 134, a sleeve 135, and a torsion spring 136.

[0055] The cylinder 133 is mounted outside the drive rod 132, and a spiral channel extending along the axial direction of the drive rod 132 is formed between the inner wall of the cylinder 133 and the outer wall of the drive rod 132, and the ball 134 can roll in the spiral channel. Among these, the axial direction of the drive rod 132 corresponds to the axial direction of the injector pen 100.

[0056] The cylinder 133 is fixed relative to the upper pen holder 11 in the circumferential direction; the upper end of the torsion spring 136 is fixed relative to the upper pen holder 11, and the lower end of the torsion spring 136 is connected to the sleeve 135; the driving rod 132 is limitedly connected with the sleeve 135 in a circumferential direction. That is, the driving rod 132 and the sleeve 135 cannot rotate relative to each other, but can rotate together; the sleeve 135 and the transmission mechanism 14 can switch between a transmission engagement state and a transmission separation state. That is, when the sleeve 135 and the transmission mechanism 14 are in a transmission engagement state, power transmission can be achieved between the two, and when the sleeve 135 and the transmission mechanism 14 are in a transmission separation state, power transmission may not be achieved between the two.

[0057] Under the action of an external force, the drive rod 132 can rotate relative to the cylinder 133 and cause the sleeve 135 to rotate together.

[0058] During operation, an external force can be exerted on the drive rod 132 to rotate the drive rod 132 in the injection dose adjustment direction. When the drive rod 132 rotates, the sleeve 135 can be rotated together, but the cylinder 133 does not move. In this way, the ball 134 can roll in one direction along the spiral channel between the drive rod 132 and the cylinder 133. Since the upper end of the torsion spring 136 is fixed relative 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 desired injection dose position, the driving rod 132, the sleeve 135 and the torsion spring 136 can be held at this position; thereafter, the stored energy of the torsion spring 136 can be released by operation, that is, the position locking of the driving 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. Upon releasing the stored energy of the torsion spring 136, the driving rod 132 and the sleeve 135 rotate in the opposite direction, and the driving force is transmitted to the transmission mechanism 14 by the engagement of the sleeve 135 and the transmission mechanism 14, thereby pushing the bottle cap 231 to move downward to achieve the drug injection.When the drive rod 132 and the sleeve 135 rotate in the opposite direction, the cylinder 133 does not move, so that the ball 134 can roll in the opposite direction and reset.

[0059] According to the above operation, the rotation degree of the sleeve 135 driven by the drive rod 132 determines the stored energy of the torsion spring 136, and the stored energy of the torsion spring 136 is related to the downward pushing stroke of the bottle cap 231, i.e., related to the injection dose of medicine.

[0060] It can be understood that the reverse rotation of the drive rod 132 and the sleeve 135 refers to the rotation in the opposite direction to the aforementioned rotation in the injection dose adjustment direction, and the rolling reverse of ball 134 is also rolling in the opposite direction to the previous direction.

[0061] Here, rotation in the dose adjustment direction is defined as positive rotation, and accordingly, rotation in the direction opposite to the adjustment dose is reverse rotation.

[0062] With the above arrangement, the injector pen 100 adopts a transmission mode in which the driving rod 132, the cylinder 133 and the ball 134 cooperate in the dose adjustment process and the transmission accuracy is high, which can ensure the accuracy of the drug dose adjustment; at the same time, in the dose adjustment process, the driving rod 132 can rotate forward relative to the cylinder 133, and in the drug injection process, the driving rod 132 can further rotate relative to the cylinder 133, so that the ball 134 rolls smoothly and resets reliably, thereby ensuring the accuracy of the dose adjustment and providing the reliability and safety of the operation of the injector pen 100.

[0063] In one embodiment, the dose adjustment mechanism 13 further includes a thumbwheel assembly 131, and a circumferential limiting structure is provided between the thumbwheel assembly 131 and the drive rod 132. When the thumbwheel assembly 131 rotates, the drive rod 132 can be rotated by the circumferential limiting structure.

[0064] In a specific implementation, the wheel assembly 131 includes a wheel 1311 and a stopper support 1312, and the wheel 1311 and the stopper support 1312 are connected in a circumferentially limited manner, and a portion of the stopper support 1312 is internally mounted in the wheel 1311, and the lower end of the wheel 1311 is rotatably mounted outside the upper pen holder 11.

[0065] In one embodiment, the drive rod 132 passes through the stop support 1312, and a circumferential limiting structure is provided between the drive rod 132 and the stop support 1312.

[0066] Specifically, the circumferential limiting structure between the stopper bracket 1312 and the drive rod 132 includes a first internal ring gear 13121 on the stopper bracket 1312, and a first locking tooth 1324 (marked in FIGS. 4 to 6) on the outer wall of the drive rod 131. Under normal conditions, the first locking tooth 1324 of the drive rod 131 can be embedded in the tooth groove of the first internal ring gear 13121, thereby limiting the circumferential position of the drive rod 131 and the stopper bracket 1312, such that the stopper bracket 1312 can cause the drive rod 132 to rotate together.

[0067] In the illustrated example, the drive rod 131 is provided with four first locking teeth 1324 along the circumferential direction. In actual applications, the quantity of first locking teeth 1324 of the drive rod 131 may be set to other numbers, for example, two or three or more. It is better to uniformly arrange the multiple first locking teeth 1324 along the circumferential direction to balance the force between the drive rod 131 and the stopper support 1312.

[0068] In other implementations, a circumferential limiting structure may also be provided between the drive rod 132 and the wheel 1311.

[0069] In practice, the user can turn the thumbwheel 1311 to cause the stop support 1312 and the drive rod 132 to rotate together to adjust the dose.

[0070] In one embodiment, the dose adjustment mechanism 13 further includes a torsion spring holder 137, which is fixed relative to the upper pen holder 11, and the cylinder 133 is sleeved in the torsion spring holder 137. The cylinder 133 may be fixed relative to the upper pen holder 11 by relative fixation with the torsion spring holder 137.

[0071] The relative fixing method of the torsion spring holder 137 and the upper pen holder 11 and the relative fixing method of the cylinder 133 and the torsion spring holder 137 can both adopt the snap-fit structure method, which is convenient for disassembly and assembly and conducive to maintenance.

[0072] The upper end of the aforementioned torsion spring 136 may be specifically connected to the torsion spring holder 137.

[0073] In a specific implementation, a limiting structure is provided between the wheel assembly 131 and the torsion spring holder 137, and the limiting structure is arranged such that the wheel assembly 131 can only rotate in one direction relative to the torsion spring holder 137, but cannot rotate in the reverse direction. In the structural configuration of the injector pen 100, the wheel assembly 131 can rotate forward relative to the torsion spring holder 137, but cannot rotate in the reverse direction. In this way, after the wheel assembly 131 causes the drive rod 132 to rotate forward to the position where the dose is desired to be adjusted, the drive rod 132, the sleeve 135, and the torsion spring 136 can be held at that position.

[0074] In one embodiment, the limiting structure between the wheel assembly 131 and the torsion spring support 137 may be a corresponding one-way ratchet gear structure.

[0075] In one embodiment, the drive 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 exerted on the drive rod 132, so as to to release the circumferential boundary between the driving rod 132 and the wheel assembly 131. That is, the driving rod 132 can move downward relative to the upper pen holder 11 when the external force is exerted on the driving rod 132, so as to disengage from the circumferential boundary with the wheel assembly 131 and further release the energy stored in the torsion spring 136. It can be understood that after the driving rod 132 is disengaged from the circumferential boundary with the wheel assembly 131, the driving rod 132 is not constrained by the wheel assembly 131, and the sleeve 135 and the torsion spring 136 are no longer constrained. The energy stored in the torsion spring 136 can be released, causing the sleeve 135 and the drive rod 132 to rotate in the opposite direction.

[0076] Specifically, when the drive rod 132 moves downward along the axial direction, the first locking tooth 1324 moves downward accordingly, and the axial position of the stopper support 1312 of the knurling assembly 131 remains unchanged, such that the first locking tooth 1324 disengages from the first inner ring gear 13121, thereby releasing the circumferential boundary between the drive rod 132 and the knurling assembly 131.

[0077] In one embodiment, the sleeve 135 may move downward in the axial direction relative to the upper pen holder 11 to engage with the transmission mechanism 14 to achieve power transmission, or move upward in the axial direction relative to the upper pen holder 11 to separate from the transmission mechanism 14 to achieve power cutoff.

[0078] In a specific implementation, the sleeve 135 and the drive rod 132 are limited and connected in the axial direction, so as to move along the axial direction together when an external force is exerted on the sleeve 135 and the drive rod 132.

[0079] In a specific implementation, the button mechanism 12 of the aforementioned injector pen 100 serves as a structure that can exert a downward force to the drive rod 132.

[0080] The button mechanism 12 includes a button assembly 121 and an elastic return member 123, and the button assembly 121 is limited and connected to the drive rod 132 along the axial direction.

[0081] During operation, the button mechanism 12 is pressed downward, and the button mechanism 12 can cause the driving rod 132 and the sleeve 135 to move downward together, release the circumferential limit connection between the driving rod 132 and the wheel assembly 131, and cause 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 drive rod 132 to rotate in the opposite direction. At this time, the sleeve 135 is engaged with the transmission mechanism 14, and the sleeve 135 can transmit power to the transmission mechanism 14 when it is rotated, so as to achieve pushing of the bottle cap 231. After the button assembly 121 is pressed, the elastic return member 123 stores energy, which is used to reset the button assembly 121 after the pressing force on the button mechanism 12 is canceled.

[0082] In terms of arrangement, the knob 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 drive rod 132.

[0083] In one embodiment, a dial 138 is further mounted outside the sleeve 135, and the sleeve 135 and the dial 138 are connected in a limited manner in the circumferential direction. The outer side of the dial 138 is the upper pen holder 11, and the upper pen holder 111 has a display window 111. When the dose is adjusted, the dial 138 can rotate with the sleeve 135, so that the user can determine the adjusted dose by the scale of the dial 138 which is displayed in the display window 111.

[0084] With reference to [Fig.4] to [Fig.7], [Fig.4] is a structural schematic diagram of the correspondence of the drive rod and the sleeve in a specific embodiment; [Fig.5] is a sectional schematic diagram of the drive rod and the sleeve shown in [Fig.4]; [Fig.6] is a structural schematic diagram of the drive rod in [Fig.4]; [Fig.7] is a structural schematic diagram of the sleeve in [Fig.4].

[0085] In one embodiment, the drive rod 132 has a socket portion 1321 extending along the axial direction, and the sleeve 135 includes a rod insertion portion 1351, which is inserted into the socket portion 1321 of the drive 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. In this way, after the rod insertion portion 1351 of the sleeve 135 is inserted into the socket portion 1321 of the drive rod 132, the drive rod 132 can cause the sleeve 135 to rotate together under the action of the mutually corresponding flat portion 13511 and the flat wall. Apparently, the flat portion 13511 and the flat wall constitute a circumferential boundary connecting structure between the drive rod 132 and the sleeve 135.

[0086] In the specific implementation, cross-sections of the mutually corresponding rod insertion portion 1351 and socket portion 1321 may be non-circular structures, e.g., rectangles, squares, triangles or polygons; cross-sections can also be other irregular shapes with planar structures.

[0087] The axial limiting structure between the drive rod 12 and the sleeve 135 can have various forms. Here is a relatively simple and reliable method.

[0088] A convex portion 1354 extending inward in the axial direction is provided on the sleeve 135, and a concave portion 1323 cooperating with the convex portion 1354 is provided on the driving rod 132. After the rod insertion portion 1351 of the sleeve 135 is inserted into the socket portion 1321 of the driving rod 132, the convex portion 1354 of the sleeve 135 can snap into the concave portion 1323 of the driving rod 132. As illustrated [Fig.5], the sleeve 135 and the driving rod 132 along the axial direction are limited by the engagement of the convex portion 1354 and the concave portion 1323.

[0089] In a specific implementation, the bottom end of the drive rod 132 near the sleeve 135 has an extension portion 1322 extending downward 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.

[0090] 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 upper portion is provided with the aforementioned convex portion 1354. After mounting, the extension portion 1322 of the drive rod 132 can extend into the inner cylinder portion 1352. The bottom end of the 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.

[0091] In other implementations, the aforementioned convex portion 1354 and the concave portion 1323 may be placed inversely, i.e., the convex portion 1354 is placed on the drive rod 132 and the concave portion 1323 is placed on the sleeve 135.

[0092] The sleeve 135 further includes an outer cylinder portion 1353 which is mounted outside the inner cylinder portion 1352. The bottom ends of the inner cylinder portion 1352 and the outer cylinder portion 1353 are connected together, and a space for accommodating 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 bottom end of the sleeve 135, so as to facilitate hooking and connecting with the lower end of the torsion spring 136.

[0093] Specifically, two or more groups of mutually corresponding concave portions 1323 and convex portions 1354 of the drive rod 132 and the sleeve 135 may be provided, which are arranged uniformly along the circumferential direction of the driving rod 132, such that the connection between the driving rod 132 and the sleeve 135 is uniformly stressed to prevent deformation. In the figure, the structure of two groups of concave portions 1323 and convex portions 1354 is illustrated.

[0094] In a specific implementation, multiple convex ribs 1355 extending outward along the radial direction are provided on the outer wall of the sleeve 135 near the bottom end, and the multiple convex ribs 1355 are arranged along the circumferential direction of the sleeve 135 to correct the concentricity degree of the sleeve 135 and the upper pen holder 11. In this way, the deformation of the sleeve 135 can be prevented from affecting the transmission effect with the transmission mechanism 14.

[0095] In one embodiment, the transmission mechanism 14 of the injector pen 100 includes a drive wheel 141, a screw 142, and a vial holder cover 143. The drive wheel 141 can be engaged or disengaged from the sleeve 135, the screw 142 is circumferentially bounded with the drive wheel 141, and is threadedly connected to the vial holder cover 143, and the lower end of the screw 142 passes through the vial holder cover 143 and can abut against the vial cap 231. Generally, a seal is provided between the screw 142 and the vial cap 231.

[0096] A clutch structure is provided between the drive wheel 141 and the sleeve 135. The clutch structure can bring the sleeve 135 and the drive wheel 141 into an engaged state when the sleeve 135 moves downward in the axial direction, such that the sleeve 135 can cause the drive wheel 141 to rotate together. When the sleeve 135 moves upward in the axial direction, the sleeve 135 and the drive wheel 141 can be separated, such that rotation of the sleeve 135 does not affect the drive wheel 141.

[0097] Referring to [Fig.8], [Fig.8] is a structural schematic diagram of the drive wheel in a specific embodiment.

[0098] In a specific implementation, the drive wheel 141 includes a cylindrical portion 1411 extending into the sleeve 135, and the outer peripheral wall of the cylindrical portion 1411 is provided with multiple convex edges 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 these two parts from jamming, and improve the reliability of operation of the injector pen 100.

[0099] The drive wheel 141 further includes a base portion 1412 attached to the lower end of the cylindrical portion 1411. The base portion 1412 is provided with multiple projections 1414 projecting upward in the axial direction near the outer edge. The multiple projections 1414 are circumferentially arranged to correct the concentricity degree 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.

[0100] In practice, the aforementioned multiple convex edges 1413 can be arranged uniformly in the circumferential direction, and the aforementioned multiple protrusions 1414 are also arranged uniformly in the circumferential direction, so that the corresponding components are stressed more uniformly and more conducive to concentricity degree correction.

[0101] In a specific implementation, the bottom end of the sleeve 135 has a second internal ring gear 1356, and the drive wheel 141 is provided with a second locking tooth 1415. When the sleeve 135 moves downward in the axial direction, the second locking tooth 1415 on the drive wheel 141 can be embedded in the tooth groove of the second internal ring gear 1356, thereby realizing the engagement of the drive wheel 141 and the sleeve 135, such that the sleeve 135 can drive the drive wheel 141 to rotate together. When the sleeve 135 moves upward in the axial direction, the second inner ring gear 1356 is disengaged from the second locking tooth 1415 of the drive wheel 141, so that the drive wheel 141 and the sleeve 135 are separated, and the drive wheel 141 does not rotate with the sleeve 135.

[0102] 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 open structure that penetrates the cylinder cavity of its inner cylinder portion 1352.

[0103] When the dose is adjusted by rotating the thumbwheel assembly 131 and the button assembly 121 is pressed, the drive rod 132 and the sleeve 135 move downward along the axial direction, the drive rod 132 is separated from the circumferential boundary of the thumbwheel assembly 131, and the sleeve 135 is engaged with the drive wheel 141. Upon releasing the stored energy of the torsion spring 136, the drive rod 132 and the sleeve 135 rotate together, causing the drive wheel 141 to rotate. When the drive wheel 141 rotates, it causes the screw 142 which is circumferentially limited to rotate together, and the screw 142 is threadedly connected to the bottle holder cover 143. Under the action of the thread, the screw 142 moves downward along the axial direction, pushing the vial stopper 231 downward to achieve drug injection.

[0104] Comparing [Fig.2] and [Fig.3] with [Fig.9] and [Fig.10], in [Fig.2] and [Fig.3], the injector pen 100 is in a first state where the drive rod 132 and the wheel assembly 131 are circumferentially limited, and the sleeve 135 and the drive wheel 141 are separated. [Fig.9] illustrates the second state where the circumferential limit of the drive rod 132 and the wheel 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 drive rod 132 is separated from the first internal ring gear 13121 of the wheel assembly 131. [Fig.10] illustrates that the sleeve 135 and the drive wheel 141 are in an engaged state after the button assembly 121 is pressed.

[0105] The specific structure and connection of the relevant parts of the lower pen cap assembly 20 of the injector pen 100 are not the essence of the present invention, which can be understood by referring to conventional technology and will not be described in detail here.

[0106] This article uses specific embodiments to explain the principles and methods of implementing the present invention. The description of the embodiments above is configured only to facilitate understanding of the method and the central idea of the present invention. It should be emphasized that, for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications fall within the scope of protection of the claims of the present invention.

Claims

Claims

1. A dose adjustment mechanism (13) of an injector pen (100), comprising: a drive rod (132), a cylinder (133), a ball (134), a sleeve (135), and a torsion spring (136); wherein the cylinder (133) is mounted outside the drive rod (132), a spiral channel extending along an axis direction of the drive rod (132) is formed between an inner wall of the cylinder (133) and an outer wall of the drive rod (132), and the ball (134) can roll in the spiral channel; the cylinder (133) and an upper pen holder (11) of the injector pen (100) are relatively fixed in a circumferential direction; an upper end of the torsion spring (136) is fixed relative to the upper pen holder (11), and a lower end of the torsion spring (136) is connected to the sleeve (135); the driving rod (132) can rotate relative to the cylinder (133) under the action of an external force;the sleeve (135) is limitedly connected with the driving rod (132) in the circumferential direction, and the sleeve (135) is configured to provide transmission cooperation with a transmission mechanism (14) of the injector pen (100).;

2. The dose adjustment mechanism (13) according to claim 1, wherein the sleeve (135) comprises a rod insertion portion (1351), the drive rod (132) comprises a socket portion (1321) extending along the axial direction, the rod insertion portion (1351) is inserted into the socket portion (1321), an outer peripheral wall of the rod insertion portion (1351) has a flat portion (13511) in the circumferential direction, and an inner orifice wall of the socket portion (1321) has a flat wall that cooperates with the flat portion (13511).

3. The dose adjustment mechanism (13) according to claim 2, wherein the dose adjustment mechanism (13) further comprises an axial limiting structure between the drive rod (132) and the sleeve (135), so as to limit a relative position of the drive rod (132) and the sleeve (135) in the axial direction.

4. The dose adjustment mechanism (13) according to claim 3, wherein the driving rod (132) or the sleeve (135) is provided with a convex portion (1354) extending in a radial direction, and the other of the driving rod (132) or the sleeve (135) is provided with a concave portion (1323), and the convex portion (1354) is configured to snap into the concave portion (1323); the axial limiting structure comprises the convex portion and the concave portion.

5. The dose adjustment mechanism (13) according to claim 4, wherein a bottom end of the drive rod (132) has an extension portion (1322) extending downward in the axial direction, the extension portion (1322) is provided with the concave portion (1323), the sleeve (135) includes an inner cylinder portion (1352), an inner cylinder wall of the inner cylinder portion (1352) close to a top end is provided with the convex portion (1354) extending inward in the radial direction.

6. The dose adjustment mechanism (13) according to any one of claims 1 to 5, wherein an outer wall of the sleeve (135) near a bottom end is provided with a plurality of convex ribs (1355) extending outward in the radial direction, and the plurality of convex ribs (1355) are arranged along a circumferential direction of the sleeve (135) to correct a degree of concentricity between the sleeve (135) and the upper pen holder (11).

7. The dose adjustment mechanism (13) according to any one of claims 1 to 5, further comprising a thumbwheel assembly (131), wherein a circumferential limiting structure is provided between the thumbwheel assembly (131) and the drive rod (132), and the thumbwheel assembly (131) is configured to cause the drive rod (132) to rotate by the circumferential limiting structure.

8. The dose adjustment mechanism (13) according to claim 7, wherein the drive rod (132) is configured to move relative to the barrel (133) toward a lower cap (20) of the injector pen (100) under the action of an external force, to release a circumferential boundary with the thumbwheel assembly (131).

9. The dose adjustment mechanism (13) according to any one of claims 1 to 5, further comprising a torsion spring holder (137), wherein the torsion spring holder (137) is fixed relative to the upper pen holder (11), and the cylinder (133) is fixed relative to the torsion spring holder (137), the torsion spring holder (137) is connected to the upper end of the torsion spring (136).

10. An injector pen (100) comprising: an upper pen holder (10) and a dose adjustment mechanism (13) installed on the upper pen holder (10), wherein the dose adjustment mechanism (13) is the dose adjustment mechanism (13) according to any one of claims 1 to 9.

11. The injector pen (100) according to claim 10, further comprising a transmission mechanism (14), wherein the sleeve (135) is configured to move downward in the axial direction relative to the upper pen holder (10) to engage with a drive wheel (141) of the transmission mechanism (14), or move upward in the axial direction relative to the upper pen holder (10) to separate from the drive wheel (141); when the sleeve (135) is in a state engaged with the drive wheel (141), the sleeve (135) is configured to drive the drive wheel (141) to rotate;the drive wheel (141) comprises a cylindrical portion (1411) extending into the sleeve (135), and an outer peripheral wall of the cylindrical portion (1411) is provided with a plurality of convex edges (1413) arranged in the circumferential direction, so as to correct the degree of concentricity of the drive wheel (141) and the sleeve (135).;

12. The injector pen (100) according to claim 11, wherein the drive wheel (141) comprises a base portion (1412) fixedly connected to a lower end of the cylindrical portion (1411), and a plurality of projections (1414) projecting upward in the axial direction are arranged near an outer edge of the base portion (1412), and the plurality of projections (1414) are arranged in the circumferential direction to correct the concentricity degree of the drive wheel (141) and the upper pen holder (11).

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