INJECTION PEN

Abstract

The present application relates to an injector pen comprising a button mechanism and a dose setting mechanism. The button mechanism comprises a button assembly comprising a button body and a button cover removably connected to each other. The dose setting mechanism comprises an operating lever. The button body comprises a downwardly extending engagement portion and having an upwardly facing first limiting surface. The operating lever comprises an upwardly extending hook portion and having a downwardly facing second limiting surface. The button cover comprises a downwardly extending post portion, and the post portion is insertable into the hook portion to push the hook portion outward in a radial direction, such that the second limiting surface abuts the first limiting surface.By optimizing the engagement structure of the knob mechanism and the dose adjustment mechanism, the reliability of the connection between the knob mechanism and the dose adjustment mechanism can be ensured. [FIG. 4].

Description

Title of the invention: INJECTION PEN Technical field

[0001] The present application relates to the technical field of medical instruments, and in particular an injector pen.

[0002] CONTEXT

[0003] Insulin injection therapy is the most commonly used treatment method in clinical work, and therefore, an injector pen for injecting insulin has emerged. The injector pen can be used repeatedly and can accurately adjust the injection dose, and only a cartridge-type bottle containing insulin needs to be replaced. In addition to insulin, the injector pen can also be used to inject other drugs.

[0004] In the related art, the injector pen comprises an upper pen tube assembly and a lower pen cap. The upper pen tube assembly comprises a button mechanism, a dose setting mechanism and a transmission mechanism, and the lower pen cap is configured for mounting a cartridge-type bottle. Kinetic energy can be stored by operating the dose setting mechanism, and the kinetic energy stored in the dose setting mechanism can be released when the button mechanism is pressed, so as to push a bottle cap of the cartridge-type bottle through the transmission mechanism, thereby realizing the injection of the medicine.

[0005] In practice, it has been found that the engagement structure of the existing button mechanism and the dose adjustment mechanism tends to loosen, and the button of the button mechanism tends to loosen, thereby rendering the injector pen unusable.

[0006] SUMMARY

[0007] An object of the present application is to provide an injector pen, which can ensure the reliability of the connection between a button mechanism and a dose setting mechanism by optimizing the engagement structure of the button mechanism and the dose setting mechanism.

[0008] In order to solve the above-mentioned technical problem, there is provided an injector pen comprising a button mechanism and a dose setting mechanism. The button mechanism comprises a button assembly comprising a button body and a button cover removably connected to each other. The dose setting mechanism comprises a control lever.

[0009] The button body includes a downwardly extending engagement portion, and the engagement portion has a first upwardly facing limiting surface. The control lever includes an upwardly extending hook portion, and the hook portion has a second downwardly facing limiting surface.

[0010] The button cover includes a downwardly extending riser portion, and the riser portion can be inserted inside the hook portion to push the hook portion outward in a radial direction, so that the second limiting surface abuts against the first limiting surface.

[0011] In one implementation, the control lever is provided with two or more hook parts, which are arranged at intervals in a circumferential direction. The hook part comprises a rod part and a hook provided at the upper end of the rod part, and the upper end of the rod part extends outward in the radial direction to form the hook.

[0012] In one implementation, the lower ends of the rod portions of the hook portions are connected by a connecting portion into an integrated structure, and an upper section of the rod portion has elastic deformation capability in the radial direction.

[0013] In one implementation, an inclined guide surface is provided at the upper end of an inner wall of the shank portion of the hook portion and configured to guide insertion of the post portion.

[0014] In one implementation, the hook portions are arranged around a central axis of the control lever, and a central axis of the riser portion coincides with the central axis of the control lever.

[0015] In one implementation, a central area of the button body is recessed downward to form the engaging portion. The engaging portion has a through hole through which the hook portion passes, and the first limiting surface is an annular surface.

[0016] In one implementation, the upright portion has a hollow structure.

[0017] In one implementation, the button cover is removably connected to the button body by a snap-fit adjustment.

[0018] In one implementation, the injector pen further comprises a wheel assembly. A circumferential limiting structure is provided between the wheel assembly and the control lever, and is configured to allow the wheel assembly to drive the control lever to rotate when the wheel rotates.

[0019] The knob assembly is connected to the thumbwheel assembly so as to be slidable in an axial direction, and is configured to drive the control lever to move downward when the knob assembly moves. downward relative to the wheel assembly so as to clear the circumferential boundary between the control lever and the wheel assembly.

[0020] In one implementation, the button mechanism further comprises a resilient return member, which is positioned between the button assembly and the wheel assembly.

[0021] With the above-mentioned solution, the hook portion of the operating lever can extend into the engagement portion of the button body. After the button cover is detachably connected to the button body, the post portion of the button cover can be inserted into the hook portion, and the hook portion is pushed outward in the radial direction, so that the second limiting surface of the hook portion abuts against the first limiting surface of the engagement portion. In this way, by the engagement between the engagement portion and the hook portion, the relative position of the button body and the operating lever in the axial direction is limited, and when the button assembly is pressed downward, the operating lever can be driven to move downward together with the button assembly.In addition, the rising part of the button cover is inserted into the hook part, so that the hook part always abuts against the engagement part, thereby ensuring the reliability of the axial boundary between the control lever and the button assembly, and effectively preventing the hook part of the control lever from detaching from the engagement part. Brief description of the drawings .

[0022] [Fig-1] is a schematic structural view of an injector pen according to a mode of completion of this request;

[0023] [Fig.2] is a schematic sectional view of the injector pen illustrated in [Fig.l];

[0024] [Fig.3] is an enlarged partial view of the area where the tube assembly is located. upper pen of [Fig.2];

[0025] [Fig.4] is a schematic sectional view of an assembly of a button assembly and a control lever of one embodiment;

[0026] [Fig.5] is an enlarged partial view of part A of [Fig.4];

[0027] [Fig.6] is a schematic structural view of a button body of a mode of realization ;

[0028] [Fig.7] is a schematic sectional view of the button body illustrated in [Fig.6];

[0029] [Fig.8] is a schematic structural perspective view of a button cover of one embodiment;

[0030] [Fig.9] is another schematic structural perspective view of a button cover of one embodiment; and

[0031] [Fig.10] is a schematic structural view of a control lever of one embodiment. List of reference signs

[0032] 100. Injector pen; 10. Upper pen tube assembly;

[0033] 20. Lower pen cap assembly; 11. Upper pen tube;

[0034] 111. Display window; 12. Button mechanism; 121. Button body;

[0035] 1211. Engaging portion; 12111. First limiting surface;

[0036] 1212. Through hole; 1213. Engagement opening; 1214. Projection;

[0037] 122. Button cover; 1221. Upright part; 1222. Lug;

[0038] 1223. Notch; 123. Elastic return member; 13. Dose adjustment mechanism

[0039] 131. Wheel assembly; 1311. Wheel; 1312. Stop support;

[0040] 13121. First part of inner toothed ring; 132. Control lever;

[0041] 1324. First tooth; 1325. Hook part; 13251. Second limiting surface;

[0042] 13252. Upright part: 13253. Hook; 13254. Guide surface;

[0043] 1326. Hole part; 1327. Connecting part; 133. Cylinder;

[0044] 134. Ball; 135. Sleeve; 136. Torsion spring;

[0045] 137. Torsion spring support; 138. Dial;

[0046] 14. Transmission mechanism; 141. Driving wheel; 142. Screw;

[0047] 143. Bottle holder cover; 21. Lower pen cap;

[0048] 22. Bottle holder cover; 23. Cartridge type bottle;

[0049] 231. Bottle plug.

[0050] DETAILED DESCRIPTION OF THE EMBODIMENTS

[0051] An injector pen is provided according to one embodiment of the present application, wherein the reliability of the connection between the button mechanism and the dose setting mechanism can be ensured by optimizing the matching structure of a button mechanism and a dose setting mechanism, so as to improve the reliability of use of the injector pen.

[0052] In order to enable those skilled in the art to better understand the solutions of the present application, the present application is described in more detail below, together with the accompanying drawings and specific embodiments.

[0053] In the present specification, the side where the button mechanism of the injector pen is located is defined as "top", and correspondingly, the side where the injection end of the injector pen is located or the side close to an injection site when in use is defined as "bottom". The length direction of the injector pen is defined as the axial direction, and the side close to the center of the injector pen is defined as "inner", and correspondingly, the side far from the The center of the injector pen is defined as “outside.” It is understood that the orientation terms are simply used for ease of description and understanding, and do not constitute a limitation of the protective framework.

[0054] Referring to FIGS. 1-3, [Fig.l] is a schematic structural view of an injector pen according to one embodiment of the present application; [Fig.2] is a schematic sectional view of the injector pen illustrated in [Fig.l]; and [Fig.3] is an enlarged partial view of the area where an upper pen tube assembly is located in [Fig.2].

[0055] In this embodiment, an injector pen 100 includes an upper pen tube assembly 10 and a lower pen cap assembly 20.

[0056] The upper pen tube assembly 10 comprises an upper pen tube 11, a button mechanism 12, a dose setting mechanism 13 and a transmission mechanism 14. The upper pen tube 11 serves as a base for mounting the button mechanism 12, the dose setting mechanism 13 and the transmission mechanism 14.

[0057] The lower pen cap assembly 20 includes a lower pen cap 21, a bottle holder 22, and a cartridge-type bottle 23. The bottle holder 22 is inserted into the lower pen cap 21 and configured to mount the cartridge-type bottle 23. An upper end of the bottle holder 22 extends out of the lower pen cap 21 to be engaged or connected to the upper pen tube 11, and is received in a lower end of the upper pen tube 11.

[0058] The transmission mechanism 14 in the upper pen tube 11 can cooperate with a bottle cap 231 of the cartridge-type bottle 23, and the dose-setting mechanism 13 can provide driving force to the transmission mechanism 14, so that the transmission mechanism 14 pushes the bottle cap 231 to move downward to realize the injection of the medicine.

[0059] It should be noted that the cartridge-like bottle 23 is a container for storing a medicament, which is not essentially a component of the injector pen 100 and which is used in conjunction with the injector pen 100. In one application, the cartridge-like bottle 23 is a replaceable component.

[0060] In this embodiment, the dose adjustment mechanism 13 comprises a wheel assembly 131, a control lever 132, a cylinder 133, a ball 134, a sleeve 135 and a torsion spring 136.

[0061] A circumferential limiting structure is provided between the control lever 132 and the thumbwheel assembly 131. The control lever 132 can be moved in an axial direction by the button mechanism 12 to release a circumferential limiting state between the control lever 132 and the thumbwheel assembly 131. wheel 131 or to restore the circumferential limitation state between the control lever 132 and the wheel assembly 131. In one embodiment, the control lever 132 can be moved downward in the axial direction to release the circumferential boundary between the control lever 132 and the wheel assembly 131, and the control lever 132 can return. That is, the control lever 132 is moved downward and then moved upward in the axial direction to return so as to restore the circumferential boundary between the control lever 132 and the wheel assembly 131. The axial movement of the control lever 132 can be achieved by operating the button mechanism 12.

[0062] The control lever 132 is inserted into the cylinder 133. A helical channel extending in the axial direction of the control lever 132 is formed between an inner cylinder wall of the cylinder 133 and an outer lever wall of the control lever 132, and the ball 134 is provided in a rolling manner in the helical channel. The axial direction of the control lever 132 is consistent with the axial direction of the injector pen 100.

[0063] The cylinder 133 does not move relative to the upper pen tube 11 in a circumferential direction. An upper end of the torsion spring 136 is fixed relative to the upper pen tube 11, and a lower end of the torsion spring 136 is connected to the sleeve 135.

[0064] The control lever 132 is fixed relative to the sleeve 135. In other words, the control lever 132 and the sleeve 135 cannot rotate relative to each other, but can rotate together.

[0065] The sleeve 135 and the transmission mechanism 14 can be switched between a transmission engagement state and a transmission disengagement state. In other words, when the sleeve 135 and the transmission mechanism 14 are in the transmission engagement state, power transmission can be performed between the two; and when the sleeve 135 and the transmission mechanism 14 are in the transmission disengagement state, power transmission cannot be performed between the two.

[0066] In one embodiment, engagement and disengagement between the sleeve 135 and the transmission mechanism 14 are achieved by axial movement of the sleeve 135.

[0067] In a specific implementation, the transmission mechanism 14 includes a drive wheel 141, a screw 142, and a bottle holder cover 143. The drive wheel 141 is engageable or disengageable from the sleeve 135. The screw 142 is circumferentially bounded relative to the drive wheel 141 and is in threaded connection with the bottle holder cover 143. A lower end of the screw 142 passes through the bottle holder cover 143 and abuts against the bottle cap 231. Usually, a gasket is arranged between the screw 142 and the bottle cap 231.

[0068] A clutch structure is provided between the drive wheel 141 and the sleeve 135. The clutch structure is provided so as to enable the sleeve 135 and the drive wheel 141 to be in the engaged state, where the sleeve 135 can drive therewith the rotation of the drive wheel 141, when the sleeve 135 moves downward in the axial direction; and to enable the sleeve 135 and the drive wheel 141 to be in the disengaged state, where the rotation of the sleeve 135 does not affect the drive wheel 141, when the sleeve 135 moves upward in the axial direction.

[0069] Since the sleeve 135 is fixed relative to the control lever 132, when the button mechanism 12 is operated, the control lever 132 and the sleeve 135 can be driven to move downward in the axial direction, so that the sleeve 135 is in transmission engagement with the drive wheel 141. And, under the action of the button mechanism 12, the control lever 132 and the sleeve 135 can also move upward in the axial direction, so that the sleeve 135 is disengaged from the drive wheel 141.

[0070] FIGS. 2 and 3 illustrate the structure of the injector pen 100 in a nominal state. The nominal state referred to herein and above refers to the state in which the relative positions of the various structures of the injector pen 100 are illustrated when the injector pen 100 is not actuated.

[0071] In a specific implementation, the button mechanism 12 comprises a button assembly and a return elastic member 123. The return elastic member 123 is provided between the button assembly and the wheel assembly 131, and the axial position of the wheel assembly 131 remains unchanged relative to the injector pen 100. The pressure exerted on the button assembly drives the control lever 132 and the sleeve 135 to move downward in the axial direction, and in this process, the return elastic member 123 is compressed and stores energy. After the pressing force on the button assembly is removed, the control lever 132 and the sleeve 135 can move upward in the axial direction to return under the action of the return elastic force of the return elastic member 123.

[0072] In a specific implementation, the dose setting mechanism 13 further comprises a dial 138, which is arranged outside the sleeve 135. The dial 138 is circumferentially bounded relative to the sleeve 135 and is connected thereto. The upper pen tube 11 is provided on an outer side of the dial 138 and the upper pen tube 11 has a display window 111. When setting the dose, the dial 138 can rotate together with the sleeve 135, so that a user can determine the set dose by means of the scale on dial 138 displayed in display window 111.

[0073] In a specific implementation, the dose setting mechanism 13 of the injector pen 100 further comprises a torsion spring holder 137, which is fixed relative to the upper pen tube 11. The upper end of the torsion spring 136 may be connected to the torsion spring holder 137. The cylinder 133 is received in the torsion spring holder 137. The cylinder 133 may be fixed relative to the upper pen tube 11 by fixing it relative to the torsion spring holder 137.

[0074] The relative attachment between the torsion spring holder 137 and the upper pen tube 11 and the relative attachment between the cylinder 133 and the torsion spring holder 137 can both be achieved by snap-fitting or other attachment means, which is convenient for disassembly and assembly and is advantageous with respect to maintenance.

[0075] 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 configured such that the wheel assembly 131 can only rotate in one direction relative to the torsion spring holder 137 and cannot rotate in the reverse direction. In the configuration of the injector pen 100, the wheel assembly 131 can rotate in the dose setting direction relative to the torsion spring holder 137, but cannot rotate in the opposite direction to the dose setting.

[0076] For example, the limiting structure between the wheel assembly 131 and the torsion spring support 137 may be a one-way ratchet and claw structure.

[0077] In the following, rotation in the dose setting direction is referred to as forward rotation, and rotation in the opposite direction to the dose setting direction is referred to as reverse rotation.

[0078] The drug injection operation of the injector pen 100 can be divided into a dose setting phase and an injection phase.

[0079] During the dose setting phase, the user can turn the thumbwheel assembly 131 in the forward direction to rotate the control lever 132, and the control lever 132 rotates the sleeve 135 and the torsion spring 136 together, so that the torsion spring 136 stores energy. During this process, the set dose can be determined via the display window 111 of the upper pen tube 11. Once the dose is set and the force applied to the thumbwheel assembly 131 is removed, the thumbwheel assembly 131 can be held in this position under the action of the limiting structure between the thumbwheel assembly 131 and the torsion spring holder 137. And correspondingly, the control lever 132, the sleeve 135 and the torsion spring 136, which are circumferentially limited relative to the wheel assembly 131, are held in this position.

[0080] In the injection phase, the button assembly of the button mechanism 12 is pressed downward to push the control lever 132 to move downward in the axial direction, and the control lever 132 drives the sleeve 135 to move downward together, so that the sleeve 135 is engaged with the drive wheel 141 of the transmission mechanism 14. And, the control lever 132 is released from the circumferential boundary with respect to a stopper support 1312, so that the energy stored in the torsion spring 136 is released. Under the action of the stored energy released from the torsion spring 136, the sleeve 135 and the control lever 132 rotate together in the reverse direction. The drive wheel 141 engaged with the sleeve 135 is rotated to together drive the screw 142 to rotate.When the screw 142 rotates, due to the threaded engagement between the screw 142 and the bottle holder cover 143, the screw 142 also moves downward in the axial direction to push the bottle cap 231 to realize the drug injection.

[0081] The button assembly of the button mechanism 12 is axially limited relative to the operating lever 132 and is connected thereto, so that when the button assembly is pressed, the button assembly can drive the operating lever 132 to move together downward in the axial direction. The present application focuses on improving the connection structure between the button assembly and the operating lever 132 to ensure the reliability of the connection between the button assembly and the operating lever 132, which will be described below in detail.

[0082] Please refer to FIGS. 4 to 10. [Fig. 4] is a schematic sectional view of the assembly of a knob assembly and a control lever of one embodiment; [Fig. 5] is an enlarged partial view of part A of [Fig. 4]; [Fig. 6] is a schematic structural view of a knob body of one embodiment; [Fig. 7] is a schematic sectional view of the knob body shown in [Fig. 6]; [Fig. 8] is a schematic perspective structural view of a knob cover of one embodiment; [Fig. 9] is another schematic perspective structural view of a knob cover of one embodiment; and [Fig. 10] is a schematic structural view of a control lever of one embodiment.

[0083] In this embodiment, the button assembly of the button mechanism 12 comprises a button body 121 and a button cover 122. The body button 121 and button cover 122 are removably connected to each other.

[0084] The button body 121 includes a downwardly extending engagement portion 1211, and the engagement portion 1211 has a first upwardly facing limiting surface 12111. The control lever 132 includes an upwardly extending hook portion 1325, and the hook portion 1325 has a second downwardly facing limiting surface 13251.

[0085] The button cover 122 includes a downwardly extending upright portion 1221. The upright portion 1221 can be inserted into the hook portion 1325 to push the hook portion 1325 radially outward, so that the second limiting surface 13251 of the hook portion 1325 abuts against the first limiting surface 12111 of the engaging portion 1211. It is understood that the hook portion 1325 has a movable space in the radial direction to ensure that the upright portion 1221 can push the hook portion 1325 outward.

[0086] With the above-mentioned solution, the hook portion 1325 of the operating lever 132 can extend into the engagement portion 1211 of the button body 121. After the button cover 122 is removably connected to the button body 121, the post portion 1221 of the button cover 122 can be inserted into the hook portion 1325 to push the hook portion 1325 outward in the radial direction, so that the second limiting surface 13251 of the hook portion 1325 abuts against the first limiting surface 12111 of the engagement portion 1211. In this way, by the engagement between the engagement portion 1211 and the hook portion 1325, the relative position of the button body 121 and the operating lever 132 in the axial direction is limited. When the button assembly is pressed downward, the control lever 132 can be driven to move downward together with the button assembly.Meanwhile, the rising portion 1221 of the knob cover 122 is inserted inside the hook portion 1325, so that the hook portion 1325 always abuts against the engaging portion 1211, thereby ensuring the reliability of the axial boundary between the operating lever 132 and the knob assembly, and effectively preventing the hook portion 1325 of the operating lever 132 from detaching from the engaging portion 1211.

[0087] In a specific implementation, the control lever 132 is provided with two or more hook portions 1325, which are arranged at intervals in the circumferential direction. Each hook portion 1325 includes a rod portion 13252 and a hook 13253 provided at the upper end of the rod portion 13252. The upper end of the rod portion 13252 extends radially outward to form the hook 13253. A hole portion 1326 is defined by the hook portions 1325. When assembled, the post portion 1221 of the button cover 122 may be inserted into the hole portion 1326 defined by the hook portions 1325, so as to push all the rod portions 13252 outward in the radial direction, so that all the hooks 13253 can abut against, and be limited by, the engagement portion 1211.

[0088] In one embodiment, the lower ends of the hook portions 1325 of the control lever 132 are integrally connected via a connecting portion 1327, as shown in [Fig. 10]. In this way, the connecting strength between each hook portion 1325 and a main body of the control lever 132 can be improved. A notch is formed between two adjacent rod portions 13252, and the notch passes through an upper end face of the control lever 132, so that an upper section of each rod portion 13252 can move radially. It is convenient that the post portion 1221 pushes the rod portion 13252 to a position where the hook 13253 abuts against the engagement portion 1211.

[0089] Specifically, an upper section of the rod portion 13252 has an elastic deformation capability in the radial direction. On the one hand, this can alleviate the problem of structural strength being affected by the stress concentration of the rod portion 13252 generated by the thrust of the post portion 1221. On the other hand, this can facilitate the disassembly of the button mechanism 12 from the operating lever 132. After the button cover 122 is detached, the rod portions 13252 can be easily moved inward in the radial direction, and the operating lever 132 can be easily separated from the button body 121. In this way, the operating lever 132 can be detached without damaging the button mechanism 12, which is beneficial for maintenance.

[0090] In a specific implementation, a central area of the knob body 121 is recessed downward to form the engagement portion 1211. The engagement portion 1211 has a through hole 1212 through which the hook portion 1325 passes, and the first limiting surface 12111 of the engagement portion 1211 is an annular surface. In this way, during assembly, it is not necessary to adjust the circumferential relative position between the control lever 132 and the knob body 121, since the hook portions 1325 of the control lever 132 can abut against the first limiting surface 12111 after passing through the through hole 1212 of the engagement portion 1211.

[0091] In the illustrated example, the control lever 132 is provided with four hook portions 1325 arranged at intervals in the circumferential direction. In other implementations, the number of hook portions 1325 may be adjusted as required.

[0092] In a specific implementation, the hook portions 1325 are arranged around a central axis of the control lever 132, and a central axis of the post portion 1221 coincides with the central axis of the control lever 132. In this way, it is advantageous to balance the pushing force applied to each hook portion 1325 by the post portion 1221 to move the hook portion 1325 outward in the radial direction, to ensure that each hook portion 1325 can well abut against the engagement portion 1211.

[0093] In a specific implementation, an inclined guide surface 13254 is provided at an upper end of an inner wall of the rod portion 13252 of the hook portion 1325 to guide the insertion of the post portion 1221. This facilitates the insertion of the post portion 1221 into the control lever 132 when the button cover 122 is assembled.

[0094] In a specific implementation, the mounting portion 1221 of the button cover 122 may be a hollow structure to save material and reduce the weight of the button cover 122.

[0095] In a specific implementation, the button cover 122 may be removably connected to the button body 121 by a snap fit. The button body 121 may be provided with an engagement opening 1213, and the button cover 122 may be provided with a lug 1222 that is engageable in the engagement opening 1213. The button cover 122 can be snap-fitted into the button body 121. When the button cover 122 is snap-fitted, the lug 1222 of the button cover 122 can extend into the engagement opening 1213 under an external force and abut against a downwardly facing inner end face of the button body 121, thereby limiting the position of the button cover 122 relative to the button body 121.

[0096] In the illustrated example, when four groups of engagement lugs 1222 and openings 1213 are provided between the button cover 122 and the button body 121. The four groups of engagement lugs 1222 and openings 1213 can be arranged uniformly in the circumferential direction, so that the engagement force between the button cover 122 and the button body 121 is relatively uniform, thereby improving the connection between the button cover 122 and the button body 121.

[0097] In other implementations, other numbers of mutually engaged engagement lugs 1222 and openings 1213 may also be provided between the button cover 122 and the button body 121. For example, two or three groups of engagement lugs 1222 and openings 1213 may be provided.

[0098] In other specific implementations, the button cover 122 may be engaged with the button body 121 in any other manner. For example, a clamping portion is provided on an outer edge of the button body 121 and configured to press the button cover 122 downward, and the clamping portion is rotatable relative to the button body 121 so as to switch from a position where the button cover 122 is pressed to a position where the button cover 122 is released.

[0099] In this embodiment, a foolproof structure may also be provided between the button cover 122 and the button body 121 to facilitate identification of the circumferential position of the button cover 122 relative to the button body 121 when they are assembled. It should be noted that, if the engagement structure between the button cover 122 and the button body 121 is symmetrical about its center, the relative circumferential position of the button cover 122 and the button body 121 does not affect the assembly of the two, and in this case, the foolproof structure may not be provided.

[0100] In one implementation, the tamper-proof structure may include a notch 1223 formed on an outer edge of the button cover 122, and a protrusion 1214 provided on an outer edge of the button body 121. The notch 1223 is matched with the protrusion 1214. When the button cover 122 is engaged with the button body 121, the protrusion 1214 is located in the notch 1223.

[0101] In this embodiment, in order to facilitate pressing of the button assembly of the button mechanism 12, the button assembly is connected to the wheel assembly 131 so as to be able to slide in the axial direction. The elastic return member 123 of the button mechanism 12 is provided between the button assembly and the wheel assembly 131.

[0102] The elastic return member 123 may be a spring or the like.

[0103] In this embodiment, the wheel assembly 131 comprises a wheel 1311 and a stopper support 1312. The stopper support 1312 is connected to the wheel 1311 in a manner of being limited in the circumferential direction relative to the wheel 1311. A portion of the stopper support 1312 is arranged inside the wheel 1311, and a lower end of the wheel 1311 is rotatably arranged outside the upper pen tube 11.

[0104] In one implementation, the control lever 132 passes through the stop support 1312 and a circumferential limiting structure is provided between the control lever 132 and the stop support 1312.

[0105] In one embodiment, the circumferential limiting structure between the stopper support 1312 and the control lever 132 comprises a first inner toothed ring portion 13121 provided on the stopper support 1312, and a first tooth 1324 provided on the outer lever wall of the control lever 132. In a nominal state, the first tooth 1324 of the control lever 132 can be inserted into a toothed groove of the first inner toothed ring portion 13121, so as to limit the circumferential positions of the control lever 132 and the stop support 1312. Thus, the stop support 1312 can drive the control lever 132 to rotate together when rotating.

[0106] In practice, the number of first teeth 1324 of the control lever 132 can be determined as needed, for example two or three or more than three. The multiple first teeth 1324 are preferably arranged uniformly in the circumferential direction, so that the force between the control lever 132 and the stop support 1312 is balanced.

[0107] In other implementations, a circumferential limiting structure may also be provided between the control lever 132 and the thumbwheel 1311.

[0108] In one application, the user may turn the thumbwheel 1311 to cause the stop support 1312 and the control lever 132 to rotate together to adjust the dose.

[0109] Specific embodiments are used herein to describe the principle and implementation of the present application, and the description of the embodiments above is used only to assist in understanding the method and the central idea of the present application. It should be noted that, for those skilled in the art, several improvements and modifications can be made to the present application without departing from the principle of the present application, and these improvements and modifications also fall within the scope of protection of the claims of the present application.

Claims

Claims

1. An injector pen comprising a button mechanism and a dose setting mechanism, wherein the button mechanism comprises a button assembly, the button assembly comprises a button body and a button cover, and the button cover is detachably connected to the button body; the dose setting mechanism comprises a control lever; the button body comprises a downwardly extending engagement portion, and the engagement portion has an upwardly facing first limiting surface; the control lever comprises an upwardly extending hook portion, and the hook portion has a downwardly facing second limiting surface;and the button cover comprises a post portion extending downwardly, and the post portion is configured to be inserted inside the hook portion to push the hook portion outward in a radial direction, such that the second limiting surface abuts against the first limiting surface.;

2. An injector pen according to claim 1, wherein the operating lever is provided with two or more hook parts, which are arranged at intervals in a circumferential direction; and wherein each hook part comprises a rod part and a hook provided at an upper end of the rod part, and the upper end of the rod part extends outward in the radial direction to form the hook.

3. An injector pen according to claim 2, wherein the lower ends of the rod portions of the hook portions are connected via an integral connecting portion, and an upper section of each rod portion has elastic deformation capability in the radial direction.

4. The injector pen of claim 2, wherein an inclined guide surface is provided at an upper end of an inner wall of each rod portion and configured to guide insertion of the post portion.

5. An injector pen according to any one of claims 2 to 4, wherein the hook portions are arranged around a central axis of the control lever, and a central axis of the upright portion coincides with the central axis of the control lever.

6. An injector pen according to any one of claims 1 to 4, wherein a central area of the button body is recessed downward to form the engagement portion, the engagement portion has a through hole through which the hook portion passes, and the first limiting surface is an annular surface.

7. An injector pen according to any one of claims 1 to 4, wherein the upright portion is of hollow structure.

8. An injector pen according to any one of claims 1 to 4, wherein the button cover is removably connected to the button body by a snap fit.

9. The injector pen according to any one of claims 1 to 4, wherein the injector pen further comprises a wheel assembly, a circumferential limiting structure is provided between the wheel assembly and the operating lever, and is configured to enable the wheel assembly to drive the operating lever to rotate when the wheel rotates, and the button assembly is connected to the wheel assembly in a manner of being slidable in an axial direction, and is configured to drive the operating lever to move downward when the button assembly moves downward relative to the wheel assembly so as to release the circumferential boundary between the operating lever and the wheel assembly.

10. An injection pen according to claim 9, wherein the button mechanism further comprises a resilient return member, which is provided between the button assembly and the wheel assembly.

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