INJECTION PEN AND ITS DOSE ADJUSTMENT MECHANISM

Abstract

The present application relates to an injector pen and a dose setting mechanism thereof. The dose setting mechanism comprises a thumbwheel, a stopper holder, and a torsion spring holder. The thumbwheel can drive the stopper holder to rotate relative to the torsion spring holder. The stopper holder is provided with a bracket, and the torsion spring holder is provided with an inner ratchet ring, the bracket being in unidirectional rotational engagement with the inner ratchet ring in a dose setting direction. The thumbwheel is provided with an arm portion located outside the bracket, and the thumbwheel is rotatable relative to the stopper holder to switch from a first position to a second position. In the first position, the thumbwheel can directly drive the stopper holder to rotate in the dose setting direction, and the bracket is in unidirectional rotational engagement with the inner ratchet ring.In the second position, the arm portion presses the console radially inward, so that the console is disengaged from the inner ratchet ring; and the thumbwheel can directly drive the stopper bracket to rotate in a direction opposite to the dose adjustment direction. Due to the optimization of the structure, the force for rotating the thumbwheel in the backward direction can be reduced, which is convenient for the backward rotation of the thumbwheel assembly in case of excessive dose adjustment. [FIG. 5].

Description

Title of the invention: INJECTOR PEN AND ITS DOSE ADJUSTMENT MECHANISM DOMAIN

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

[0002] 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.

[0003] 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.

[0004] The dose setting mechanism drives a torsion spring to rotate by rotating a thumbwheel to store kinetic energy in the torsion spring, and a dial also rotates to display the set dose. And, the torsion spring is held in an energy storage position by the limited fit between a stop bracket engaged with the thumbwheel and a torsion spring bracket. Once the kinetic energy stored in the torsion spring is released to perform the injection, the boundary between the stop bracket and the torsion spring bracket is released, and the thumbwheel and the stop bracket can return and cause the dial to return.

[0005] In practice, it may happen that the thumbwheel rotates excessively in the forward direction and has to rotate in the reverse direction when adjusting the dose. With the design of the existing dose adjustment mechanism, the force for rotating the thumbwheel in the reverse direction is large, which is not easy to implement. SUMMARY

[0006] An object of the present application is to provide an injector pen and its dose adjustment mechanism. By optimizing the structure, the force for rotating the thumbwheel in the backward direction can be reduced, which is convenient for rotating the thumbwheel assembly backward in case of excessive dose adjustment, thereby improving operability.

[0007] In order to solve the above-mentioned technical problem, there is provided a dose adjustment mechanism of an injector pen, and the dose adjustment mechanism comprises a thumb wheel, a stopper holder and a torsion spring holder.

[0008] The thumbwheel can cause the stop bracket to rotate relative to the torsion spring bracket.

[0009] The stopper support is provided with a console, and the torsion spring support is provided with an inner ratchet ring, the console being in unidirectional rotational engagement with the inner ratchet ring in a dose adjustment direction. The thumbwheel is provided with an arm portion located outside the console.

[0010] The thumbwheel can rotate relative to the stop support to switch from a first position to a second position. In the first position, the thumbwheel can directly drive the stop support to rotate in the dose setting direction, and the console is in unidirectional rotational engagement with the inner ratchet ring. In the second position, the arm portion presses the console radially inward, so that the console is disengaged from the inner ratchet ring; and the thumbwheel can directly drive the stop support to rotate in a direction opposite to the dose setting direction.

[0011] In one implementation, one of the thumbwheel and the stopper support is provided with a protruding block extending in a radial direction, and the other is provided with a sliding groove extending in a circumferential direction. The protruding block extends into the sliding groove and is circumferentially rotatable in the sliding groove. The sliding groove has a first groove wall and a second groove wall in the circumferential direction. When the protruding block abuts the first groove wall, the thumbwheel is in the first position. When the protruding block abuts the second groove wall, the thumbwheel is in the second position.

[0012] In one implementation, two or more groups of the protruding blocks and the sliding grooves are provided, which cooperate with each other, and the two or more groups of the protruding blocks and the sliding grooves are uniformly arranged in the circumferential direction of the wheel.

[0013] In one implementation, a return structure is provided between the wheel and the stop support. When the wheel is in the second position, the return structure can generate a restoring force to rotate the wheel to the first position in the dose setting direction.

[0014] In one implementation, the biasing structure comprises a limiting rib, and a limiting hole extending in the circumferential direction. One of the limiting rib and the limiting hole is located on the thumbwheel, and the other of the limiting rib and the limiting hole is located on the stopper support. The limiting rib extends into the limiting hole and is configured such that, when the thumbwheel is in the second position, the limiting rib is pressed by a hole wall of the limiting hole to generate a deformation force for rotating the thumbwheel to the first position.

[0015] In one implementation, the dose adjustment mechanism further comprises a control lever.

[0016] At least a portion of the stopper support is disposed in the thumbwheel. An upper end of the control lever passes through the stopper support, and a circumferential limiting structure is provided between the control lever and the stopper support, so that the stopper support can drive the control lever to rotate.

[0017] The control lever is movable in an axial direction relative to the stop support to switch from a position where the control lever is circumferentially limited relative to the stop support to a position where the control lever is released from the circumferential limit relative to the stop support.

[0018] In one implementation, the stopper support comprises a support barrel portion, and the thumbwheel comprises an outer cylindrical member and an inner cylindrical member. The support barrel portion is disposed in the inner cylindrical member. The outer cylindrical member is configured to be rotatably engaged with an upper pen tube of the injector pen; and the circumferential limiting structure is provided between the control lever and the support barrel portion.

[0019] In one implementation, the dose setting mechanism further comprises a cylinder, a ball, a sleeve, and a torsion spring.

[0020] The cylinder is disposed outside the control lever and is inserted into the support barrel portion. A helical channel extending in the axial direction of the control lever is formed between an inner cylinder wall of the cylinder and an outer lever wall of the control lever, and the ball is provided in a rolling manner in the helical channel.

[0021] The cylinder is circumferentially limited relative to the torsion spring support and is connected thereto; and the control lever is fixed relative to the sleeve. An upper end of the torsion spring is connected to the torsion spring support. torsion spring, and a lower end of the torsion spring is connected to the sleeve.

[0022] In one implementation, multiple protruding ribs extending outward in the radial direction are provided on an outer sleeve wall of the sleeve near the lower end, and the multiple protruding ribs are arranged in the circumferential direction of the sleeve to correct the concentricity of the sleeve and the upper pen tube of the injector pen.

[0023] Also provided is an injector pen, comprising an upper pen tube, and the dose setting mechanism described above and mounted on the upper pen tube.

[0024] According to the solution of the present application, the thumbwheel assembly of the dose setting mechanism of the injector pen is structurally optimized. When the dose of the injector pen is set, the thumbwheel is rotated forward, and once the thumbwheel is rotated to the first position, the thumbwheel drives the stopper holder to rotate together to set the dose. When the thumbwheel is excessively rotated in the forward direction, it can be rotated in the reverse direction. At the start of the reverse rotation, the thumbwheel is in the first position relative to the stopper holder. When the thumbwheel is rotated in the reverse direction, the stopper holder does not rotate together with the thumbwheel until the thumbwheel rotates to the second position.When the thumbwheel rotates from the first position to the second position relative to the stopper support, the arm portion of the thumbwheel exerts radial inward pressure on the bracket, so that the bracket is disengaged from the inner ratchet ring. Therefore, when the thumbwheel continues to rotate in the reverse direction from the second position, the stopper support can be driven by the thumbwheel to rotate together in the reverse direction without hindrance from the inner ratchet ring, so that the dose can be adjusted in the reverse direction, which is convenient for performing overdose adjustment to the correct dose. The thumbwheel assembly of the dose adjustment mechanism and its associated structure are provided such that the thumbwheel assembly can be rotated in the reverse direction to perform reverse dose adjustment after overdose adjustment.The backward rotation resistance is reduced and this is beneficial for backward adjustment. Therefore, more precise dose control of the injector pen is more convenient, which improves the operability and safety of use of the injector pen. Brief description of the drawings

[0025] [Fig-1] is a schematic structural view of an injector pen according to a mode of completion of this request;

[0026] [Fig.2] is a schematic sectional view of the injector pen illustrated in [Fig.l];

[0027] [Fig.3] is an enlarged partial view of the area where the upper pen tube assembly of [Fig.2] is located;

[0028] [Fig.4] is a schematic sectional view of the assembly of a control lever, a thumbwheel, a stop support and a torsion spring support of one embodiment;

[0029] [Fig.5] is a top view of a thumbwheel, a stop support and a torsion spring support in a first position of an embodiment;

[0030] [Fig.6] is a top view of a thumbwheel, a stop support and a torsion spring support in a second position of one embodiment;

[0031] [Fig.7] is a schematic structural view illustrating the engagement of the stopper support with the torsion spring support of one embodiment;

[0032] [Fig.8] is a schematic structural view of a stop support of one embodiment;

[0033] [Fig.9] is a front view of the stop support illustrated in [Fig.8];

[0034] [Fig. 10] is a top view of the stop support illustrated in [Fig.9];

[0035] [Fig. 11] is a bottom view of the stop support illustrated in [Fig.9];

[0036] [Fig. 12] is a schematic structural perspective view of a wheel of a embodiment, seen from above;

[0037] [Fig. 13] is a schematic structural perspective view of the wheel of one embodiment, seen from below;

[0038] [Fig. 14] is a schematic structural view of a torsion spring support of one embodiment; and

[0039] [Fig. 15] is a schematic structural view of a sleeve of one embodiment. List of reference signs

[0040] 100. Injector pen; 10. Upper pen tube assembly;

[0041] 20. Lower pen cap assembly, 11. Upper pen tube;

[0042] 111. Display window; 12. Button mechanism;

[0043] 121. Button-forming assembly; 123. Elastic return member;

[0044] 13. Dose adjustment mechanism; 130. Wheel;

[0045] 1301. Arm part; 1302. Sliding groove;

[0046] 13021. First groove wall; 13022. Second groove wall;

[0047] 1303. Limiting hole; 1304. External cylindrical member;

[0048] 1305. Inner cylindrical member; 131. Stop support;

[0049] 1311. Console; 1312. Projecting block;

[0050] 1313. Limiting rib; 1314. Support barrel part;

[0051] 13121. First part of inner toothed ring; 132. Control lever

[0052] 1324. First tooth; 133. Cylinder;

[0053] 134. Ball; 135. Sleeve

[0054] 1351. Insertion rod part; 1352. Inner sleeve part;

[0055] 1353. Outer sleeve portion; 1355. Projecting rib;

[0056] 136. Torsion spring; 137. Torsion spring support;

[0057] 1371. Inner ratchet ring; 138. Dial;

[0058] 14. Transmission mechanism; 141. Driving road;

[0059] 142. Screw; 143. Bottle holder cover;

[0060] 21. Lower pen cap; 22. Bottle holder;

[0061] 23. Cartridge type bottle; 231. Bottle stopper. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0062] The embodiments of the present application provide an injector pen and its dose setting mechanism. By optimizing the structure of the dose setting mechanism, the rotation force of the wheel assembly in the backward direction can be reduced, which is convenient for the backward rotation of the wheel assembly in case of excessive dose setting, thus having good operability.

[0063] For ease of understanding and conciseness of the description, an injector pen and its dose setting mechanism will be described below, and the injector pen illustrated in the accompanying drawings is used as the main subject of the description to describe specific embodiments in detail.

[0064] In this 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 center of the injector pen is defined as "outer". It is understood that the orientation terms are merely used for ease of description and understanding, and do not constitute a limitation of the protective frame.

[0065] 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].

[0066] In this embodiment, an injector pen 100 includes an upper pen tube assembly 10 and a lower pen cap assembly 20.

[0067] 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 adjustment mechanism 13 and the transmission mechanism 14.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] In this embodiment, the dose setting mechanism 13 comprises a knob assembly, which can be rotated relative to the upper pen tube 11 to perform the dose setting. When the knob assembly is rotated in the dose setting direction, a driving force corresponding to the injection dose can be stored. Under the action of the knob mechanism 12, the stored driving force can be released and transmitted to the bottle cap 231 via the transmission mechanism 14, so that the bottle cap 231 is moved downward by a stroke corresponding to the injection dose, thereby performing the injection of medicine at a given dose.

[0072] In order to simplify the description and facilitate understanding, rotation in the direction of dose adjustment is defined herein as forward rotation and, therefore, rotation in the direction opposite to the direction of dose adjustment is designated reverse rotation.

[0073] In this embodiment, the dose adjustment mechanism 13 further comprises a control lever 132, a cylinder 133, a ball 134, a sleeve 135 and a torsion spring 136.

[0074] A circumferential limiting structure is provided between the control lever 132 and the wheel assembly.

[0075] 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.

[0076] The cylinder 133 is fixed 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.

[0077] 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.

[0078] 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.

[0079] When rotated in the forward direction, the wheel assembly drives the control lever 132 to rotate. When the control lever 132 rotates, the sleeve 135 can be rotated together, but the cylinder 133 does not move, so that the ball 134 can roll along the helical channel between the control lever 132 and the cylinder 133 in one direction. Since the upper end of the torsion spring 136 is fixed relative to the upper pen tube 11 and the lower end of the torsion spring 136 is connected to the sleeve 135, the lower end of the torsion spring 136 rotates with the sleeve 135 to store energy, so as to form a driving force to then push the bottle cap 231 to move downward to perform the injection. When the wheel assembly is turned to a position corresponding to the desired injection dose, it can be held in that position.Therefore, the control lever 132, the sleeve 135 and the torsion spring 136 are also held in this position. The energy stored in the torsion spring 136 can then be released by actuation of the button mechanism 12. Specifically, the button mechanism 12 can be actuated to unlock the control lever 132, the sleeve 135 and the torsion spring 136, and to allow the sleeve 135 and the transmission mechanism 14 to be in a transmission engaged state. When the energy stored in the torsion spring 136 is released, the control lever 132 and the sleeve 135 rotate in the reverse direction, and the driving force is transmitted to the transmission mechanism 14 via the engagement between the sleeve 135 and the transmission mechanism 14, so that the bottle cap 231 is pushed down to realize the drug injection. When the control lever 132 and the sleeve 135 are rotated in the reverse direction, the cylinder 133 does not move, so that the ball 134 can roll in the opposite direction to return.

[0080] In a specific implementation, a dial 138 is provided outside the sleeve 135, and the sleeve 135 is connected to the dial 138 so as to be circumferentially limited relative to the dial 138. The upper pen tube 11 is provided outside the dial 138 and has a display window 111. During dose setting, the dial 138 can rotate with the sleeve 135, so that a user can determine the set dose by means of the scale on the dial 138 displayed in the display window 111.

[0081] It can be seen from the above process that the dose is adjusted by rotating the wheel assembly in the forward direction, and the user can observe whether the wheel assembly is rotated in place through the display window 111 of the upper pen tube 11 during the process. However, in actual operation, a problem of excessive rotation often occurs. For example, the wheel assembly should be rotated one turn in the forward direction according to the dose needed to be injected, but in operation, it is rotated more than one turn. In this case, in order to avoid a safety accident caused by excessive injection of medicine, it is necessary to rotate the wheel assembly in the opposite direction, that is, a backward adjustment is necessary to ensure accurate dose adjustment.However, due to its structural design, the existing thumbwheel assembly can only rotate in one direction (i.e., in the forward direction); or it can rotate in two directions but has very large rotation resistance during backward adjustment, which is not easy to implement. The present application focuses on improving the thumbwheel assembly of the dose adjustment mechanism 13, so as to reduce the rotation force of the thumbwheel in the backward direction, i.e., to reduce the rotation resistance of the thumbwheel assembly in the backward direction, thereby facilitating backward rotation of the thumbwheel assembly when the dose adjustment is excessive.

[0082] The related structure for storing energy when the wheel assembly rotates in the forward direction is merely an example. In practical applications, the related structure for rotating the torsion spring 136 to store energy may be implemented in any other shape, and is not limited to the arrangement of the control lever 132, the cylinder 133, the ball 134 and the sleeve 135.

[0083] The thumbwheel assembly and its associated structure will be described in detail below. Please refer to FIGS. 4 to 7. [Fig. 4] is a schematic sectional view of the assembly of a control lever, a thumbwheel, a stopper bracket, and a torsion spring bracket of one embodiment; [Fig. 5] is a top view of the thumbwheel, the stopper bracket, and the torsion spring bracket in a first position of one embodiment; [Fig. 6] is a top view of the thumbwheel, the stopper bracket, and the torsion spring bracket in a second position of one embodiment; and [Fig. 7] is a schematic structural view illustrating the engagement of the stopper bracket with the torsion spring bracket of one embodiment.

[0084] In this embodiment, the dose setting mechanism 13 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 can be connected to the torsion spring holder 137. The cylinder 133 is arranged in the torsion spring holder 137, and the cylinder 133 can be fixed relative to the upper pen tube 11 by fixing it relative to the torsion spring holder 137.

[0085] 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 in any other manner, which is convenient for disassembly and assembly and is advantageous with respect to maintenance.

[0086] The knob assembly of the dose setting mechanism 13 comprises a knob 130 and a stopper holder 131. A lower end of the knob 130 is rotatably arranged outside an upper end of the upper pen tube 11. The stopper holder 131 and the torsion spring holder 137 are both located inside the knob 130, and the stopper holder 131 can cooperate with the torsion spring holder 137.

[0087] The thumbwheel 130 can cause the stop bracket 131 to rotate relative to the torsion spring bracket 137. The stop bracket 131 is provided with a bracket 1311, and the torsion spring bracket 137 has an inner ratchet ring 1371. The bracket 1311 can rotate unidirectionally in the dose setting direction relative to the ratchets of the inner ratchet ring 1371. In other words, once the bracket 1311 is engaged in the ratchets of the inner ratchet ring 1371, the bracket 1311 can smoothly rotate forward (in the dose setting direction) along the inner ratchet ring 1371, However, the console 1311 cannot rotate smoothly in the reverse direction due to the resistance of the inner ratchet ring 1371.

[0088] The thumbwheel 130 is provided with an arm portion 1301 located on an outer side of the bracket 1311. The thumbwheel 130 can rotate between a first position and a second position relative to the stopper support 131. In the first position, the thumbwheel 130 can directly drive the stopper support 131 to rotate forward, and the bracket 1311 is in unidirectional rotational engagement with the inner ratchet ring 1371, i.e., the inner ratchet ring 1371 prevents the bracket 1311 from rotating in the reverse direction. In the second position, the arm portion 1301 of the thumbwheel 130 presses against the bracket 1311 inwardly in the radial direction to disengage the bracket 1311 from the inner ratchet ring 1371, so that the thumbwheel 130 can directly drive the stopper bracket 131 to rotate in the reverse direction.

[0089] As illustrated in [Fig. 5], the thumbwheel 130 is in the first position relative to the stop support 131; and as illustrated in [Fig. 6], the thumbwheel 130 is in the second position relative to the stop support 131. In FIGS. 5 and 6, the clockwise rotation direction is the forward rotation direction of the dose setting, and the counterclockwise rotation direction is the reverse rotation direction opposite to the dose setting direction.

[0090] It is understood that, in the second position, since the arm portion 1301 of the thumbwheel 130 presses against the bracket 1311 inwardly in the radial direction so that the bracket 1311 is disengaged from the inner ratchet ring 1371, the bracket 1311 can rotate in the reverse direction without hindrance from the inner ratchet ring 1371. The expression "the bracket 1311 is in unidirectional rotational engagement with the inner ratchet ring 1371", as mentioned above, means the state in which the bracket 1311 is meshed with the ratchets of the inner ratchet ring 1371, or the bracket 1311 is received in a toothed groove between two adjacent ratchets of the inner ratchet ring 1371.It is also understood that, in the first position, the arm portion 1301 of the thumbwheel 130 does not exert a radial inward pressure force on the bracket 1311, or exerts a small force on the bracket 1311 that is not sufficient to disengage the bracket 1311 from the inner ratchet ring 1371, i.e., the bracket 1311 remains in unidirectional rotational engagement with the inner ratchet ring 1371.

[0091] The engagement between the bracket 1311 and the inner ratchet ring 1371 is configured such that: the bracket 1311 can rotate in the forward direction to adjust the dose along the inner ratchet ring 1371, but it is prevented from rotating in the reverse direction. In other words, when the stopper support 131 rotates in the forward direction, the bracket 1311 can rotate smoothly along the inner ratchet ring 1371. When the force for rotation of the stopper support 131 is removed, the stopper support 131 can be held in position by virtue of the engagement between the bracket 1311 and the inner ratchet ring 1371, and the bracket 1311 cannot rotate backward along the inner ratchet ring 1371 without an external force. For the meshing engagement of the bracket 1311 and the inner ratchet ring 1371, please refer to [Fig. 7]. Referring to the orientation shown in [Fig. 7], the bracket 1311 can rotate clockwise relative to the inner ratchet ring 1371, but the bracket 1311 cannot rotate counterclockwise relative to the inner ratchet ring 1371 under the interference of the inner ratchet ring 1371.

[0092] It is understood that the wheel 130 can rotate between the first position and the second position relative to the stop support 131.

[0093] With the above-mentioned solution, when the dose of the injector pen 100 is adjusted, the thumbwheel 130 is rotated in the forward direction to the first position, and then drives the stopper support 131 to rotate together, so as to achieve the dose adjustment. If the thumbwheel 130 is excessively rotated in the forward direction, it is necessary to rotate the thumbwheel 130 in the reverse direction. At the beginning of the reverse rotation, the thumbwheel 130 is in the first position relative to the stopper support 131. Then, the thumbwheel 130 is rotated in the reverse direction, and the stopper support 131 is not rotated together with the thumbwheel 130 until the thumbwheel 130 is rotated to the second position.When the thumbwheel 130 is rotated from the first position to the second position relative to the stopper support 131, the arm portion 1301 of the thumbwheel 130 presses against the bracket 1311 inward in the radial direction, so as to disengage the bracket 1311 from the inner ratchet ring 1371. Therefore, when the thumbwheel 130 continues to rotate in the reverse direction from the second position, the stopper support 131 can be driven by the thumbwheel 130 to rotate together in the reverse direction without hindrance from the inner ratchet ring 1371, so that the dose can be adjusted in the reverse direction, which is convenient for adjusting the excessive dose into the correct dose.

[0094] It is apparent from the above that the wheel assembly of the dose adjustment mechanism 13 and its associated structure are provided such that the wheel assembly can be rotated backward to perform reverse dose adjustment after excessive dose adjustment, thereby facilitating more precise control of the injection dose of the injector pen 100, thereby improving the operability and safety of use of the injector pen 100.

[0095] In this embodiment, a biasing structure is provided between the thumbwheel 130 and the stopper support 131, and is configured to generate a biasing force to rotate the thumbwheel 130 forward toward the first position when the thumbwheel 130 is in the second position. In this manner, once the thumbwheel 130 is rotated in the rearward direction and the external force applied to the thumbwheel 130 is removed, the thumbwheel 130 can rotate forward toward the first position relative to the stop support 131 under the restoring action of the restoring structure. Thus, the arm portion 1301 of the thumbwheel 130 no longer exerts an inward radial pressing force on the bracket 1311, so that the bracket 1311 can move outward in the radial direction to engage with the inner ratchet ring 1371, thereby holding the stop support 131 in the set position.

[0096] Please refer to FIGS. 8 to 14. [Fig. 8] is a schematic structural view of a stopper support of an embodiment; [Fig. 9] is a front view of the stopper support shown in [Fig. 8]; [Fig. 10] is a top view of the stopper support shown in [Fig. 9]; [Fig. 11] is a bottom view of the stopper support shown in [Fig. 9]; [Fig. 12] is a schematic perspective structural view of a thumbwheel of an embodiment from a top view; [Fig. 13] is a schematic perspective structural view of the thumbwheel of an embodiment from a bottom view; and [Fig. 14] is a schematic structural view of a torsion spring support of an embodiment.

[0097] In a specific implementation, the knurl 130 is provided with a sliding groove 1302 extending in the circumferential direction, and the stopper support 131 is provided with a protruding block 1312 extending in the radial direction. After assembling the stopper support 131 and the knurl 130, the protruding block 1312 of the stopper support 131 can extend into the sliding groove 1302 and can rotate circumferentially in the sliding groove 1302. The sliding groove 1302 has a first groove wall 13021 and a second groove wall 13022 in the circumferential direction, which are used to limit the position of the knurl 130 relative to the stopper support 131.

[0098] When the protruding block 1312 abuts against the first groove wall 13021, the knurl 130 is in the first position relative to the stopper support 131, as illustrated in [Fig. 5]. When the knurl 130 is rotated in a direction indicated by a hollow arrow in [Fig. 5] (i.e., clockwise), since the first groove wall 13021 abuts against the protruding block 1312, the knurl 130 can directly drive the stopper support 131 to rotate clockwise.

[0099] When the protruding block 1312 abuts against the second groove wall 13022, the thumbwheel 130 is located in the second position relative to the abutment support 131, as illustrated in [Fig. 6]. When the knob 130 is rotated in a direction indicated by a hollow arrow in [Fig. 6] (i.e., counterclockwise), since the second groove wall 13022 abuts against the protruding block 1312, the thumbwheel 130 can directly drive the rotation of the stop support 131 counterclockwise.

[0100] It is understood that, if the thumbwheel 130 in the state illustrated in [Fig.5] is rotated counterclockwise, it is first rotated relative to the stopper support 131 due to a circumferential gap formed between the protruding block 1312 and the sliding groove 1302 until the second groove wall 13022 of the sliding groove 1302 abuts against the protruding block 1312, and then rotates the stopper support 131 counterclockwise. If the thumbwheel 130 in the state shown in [Fig. 6] is rotated clockwise, it is first rotated relative to the stopper support 131 due to a circumferential gap formed between the protruding block 1312 and the sliding groove 1302 until the first groove wall 13021 of the sliding groove 1302 abuts against the protruding block 1312, and then rotates the stopper support 131 clockwise.

[0101] In one embodiment, two or more groups of protruding blocks 1312 and sliding grooves 1302 that cooperate with each other may be provided between the knurling wheel 130 and the stopper support 131, and may be arranged uniformly in the circumferential direction of the knurling wheel 130. In this way, the relative rotation between the knurling wheel 130 and the stopper support 131 can be smooth and even, and the stress is balanced when the knurling wheel 130 and the stopper support 131 rotate together.

[0102] As illustrated in the figures, two groups of mutually cooperating protruding blocks 1312 and sliding grooves 1302 are located between the wheel 130 and the stop support 131. In other implementations, three, four, or more groups of mutually cooperating protruding blocks 1312 and sliding grooves 1302 may be provided, if the structure permits.

[0103] In the illustrated example, the protruding block 1312 is provided on the stop support 131, and the sliding groove 1302 is formed on the knurl 130. In other implementations, the protruding block 1312 and the sliding groove 1302 may also be provided in a reversed manner, i.e., the protruding block 1312 is provided on the knurl 130 and the sliding groove 1302 is formed on the stop support 131.

[0104] In a specific implementation, the biasing structure between the thumbwheel 130 and the stopper support 131 comprises a limiting rib 1313, and a limiting hole 1303 extending in the circumferential direction. In the illustrated example, the limiting rib 1313 is provided on the stopper support 131, and the limiting hole 1303 is formed on the thumbwheel 130, the limiting rib 1313 extending into the limiting hole 1303. The limiting rib 1313 and the limiting hole 1303 are configured such that, when the thumbwheel 130 is in the second position, the limiting rib 1313 is pressed and deformed by a hole wall. of the limiting hole 1303 so as to generate a deformation force to rotate the thumbwheel 130 to the first position. In other words, when the thumbwheel 130 is rotated relative to the stopper support 131, the limiting rib 1313 can also slide in the circumferential direction in the limiting hole 1303, but the limiting rib 1313 has a sliding stroke in the limiting hole 1303 smaller than that of the protruding block 1312 in the sliding groove 1302. In this way, after the thumbwheel 130 is rotated to the second position relative to the stopper support 131, the limiting rib 1313 is pressed and deformed by the hole wall of the limiting hole 1303 due to the limited sliding stroke in the limiting hole 1303.Once the external force applied to the thumbwheel 130 is removed, the limiting rib 1313 is biased under the deformation force to rotate the thumbwheel 130 to the first position, so as to release the force of the arm portion 1301 of the thumbwheel 130 pressing against the bracket 1311. Therefore, the bracket 1311 can return to unidirectional rotational engagement with the inner ratchet ring 1371.

[0105] It is evident that the limiting rib 1313 has a capacity for compression deformation.

[0106] In other implementations, the limiting rib 1313 may also be provided on the thumbwheel 130, and the limiting hole 1303 engaged with the limiting rib 1313 may also be formed on the stopper support 131.

[0107] In a specific implementation, at least a portion of the stopper support 131 is arranged inside the thumbwheel 130. An upper end of the control lever 132 passes through the stopper support 131, and a circumferential limiting structure is provided between the control lever 132 and the stopper support 131, so that the stopper support 131 can drive the control lever 132 to rotate. In addition, the control lever 132 can also move in the axial direction relative to the stopper support 131 so as to switch from a position where the control lever 132 is circumferentially limited relative to the stopper support 131 to a position where the control lever 132 is free of the circumferential limit relative to the stopper support 131. In this way, the energy stored in the torsion spring 136 can be released by removing the circumferential boundary between control lever 132 and stop support 131.

[0108] In one embodiment, the stopper support 131 comprises a support barrel portion 1314, and the thumbwheel 130 comprises an outer cylindrical member 1304 and an inner cylindrical member 1305. The outer cylindrical member 1304 is rotatably engaged with the upper pen tube 11. The support barrel portion 1314 of the stopper support 131 may be arranged in the inner cylindrical member 1305, and the connecting portion between the outer cylindrical member 1304 and the cylindrical member interior 1305 may be provided with a structure such as the sliding groove 1302 or the limiting hole 1303 which is engaged with the stopper support 131.

[0109] In this way, the upper end of the control lever 132 can pass through the support barrel portion 1314 of the stopper support 131, and the circumferential limiting structure can be provided between the control lever 132 and the support barrel portion 1314.

[0110] In one embodiment, the circumferential limiting structure between the control lever 132 and the support barrel portion 1314 comprises a first inner toothed ring portion 1315 provided on the support barrel portion 1314 and a first tooth 1324 provided on the control lever 132. In the nominal state, the first tooth 1324 of the control lever 132 and the first inner toothed ring portion 1315 of the stopper support 131 are in the same axial position, and the first tooth 1324 can be received in a tooth groove of the first inner toothed ring portion 1315, so that the stopper support 131 can drive the control lever 132 to rotate together when rotating.When the control lever 132 is moved in the axial direction relative to the stopper support 131 under the action of an external force, the first tooth 1324 of the control lever 132 can be disengaged from the first inner toothed ring portion 1315, thereby releasing the circumferential boundary between the control lever 132 and the stopper support 131.

[0111] In this embodiment, the axial movement of the control lever 132 is achieved by the actuation of the button mechanism 12. The button mechanism 12 is provided at the upper end of the control lever 132. The button mechanism 12 comprises a button assembly 121 and a resilient return member 123, and the button assembly 121 is connected to the control lever 132 so as to be axially limited relative to the control lever 132.

[0112] After pressing the button assembly 121, the control lever 132 can be pushed to move downward in the axial direction to release the circumferential boundary between the control lever 132 and the stopper support 131. After the pressing force on the button assembly 121 is removed, the button assembly 121 can return under the action of the elastic return member 123, so as to drive the control lever 132 to move upward in the axial direction to restore the circumferential boundary with respect to the stopper support 131.

[0113] In this embodiment, the transmission mechanism 14 of the injector pen 100 comprises a drive wheel 141, a screw 142 and a bottle holder cover 143. The drive wheel 141 can be engaged or disengaged from the sleeve 135. The screw 142 is circumferentially limited 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 provided between the screw 142 and the bottle cap 231.

[0114] A clutch structure is provided between the drive wheel 141 and the sleeve 135. The clutch structure is configured such that the sleeve 135 can be engaged with the drive wheel 141 when the sleeve 135 moves downward in the axial direction, thereby enabling the sleeve 135 to jointly rotate the drive wheel 141. The clutch structure is further configured such that the sleeve 135 can be disengaged from the drive wheel 141 when the sleeve 135 moves upward in the axial direction, thereby enabling the drive wheel 141 to be free from rotation of the sleeve 135.

[0115] Since the sleeve 135 is fixed relative to the control lever 132, the control lever 132 can drive the sleeve 135 to move downward in the axial direction when pressing the button mechanism 12, so that the sleeve 135 can be in transmission engagement with the drive wheel 141. Upon return, the control lever 132 and the sleeve 135 move upward in the axial direction to disengage the sleeve 135 from the drive wheel 141.

[0116] FIGS. 2 and 3 illustrate the structures 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.

[0117] Please refer to [Fig. 15], which is a schematic structural view of a sleeve of one embodiment.

[0118] In this embodiment, the sleeve 135 comprises an insertion rod portion 1351, which can be inserted into an insertion hole of the control lever 132. The cross-section of the insertion rod portion 1351 and the cross-section of the insertion hole of the control lever 132 are not circular, so that the control lever 132 can drive the sleeve 135 to rotate together when rotating.

[0119] Between the sleeve 135 and the control lever 132, there is also a convex portion and a concave portion which are engaged with each other in the radial direction, so as to provide an axial boundary between the sleeve 135 and the control lever 132, allowing the control lever 132 to drive the sleeve 135 to move together in the axial direction.

[0120] The sleeve 135 further comprises an inner sleeve portion 1352 and an outer sleeve portion 1353. A lower end of the inner sleeve portion 1352 and a lower end of the outer sleeve portion 1353 are connected to form a space for housing the torsion spring 136 between them.

[0121] The outer sleeve wall of the sleeve 135 near the lower end, i.e., the lower end of the outer sleeve portion 1353, is provided with multiple protruding ribs 1355 extending outward in the radial direction, and the multiple protruding ribs 1355 are arranged in the circumferential direction of the sleeve 135 to correct the concentricity of the sleeve 135 and the upper pen tube 11. In this way, reliable engagement between the sleeve 135 and the transmission mechanism 14 can be ensured to achieve reliable power transmission.

[0122] The operation process of the injector pen 100 is briefly described as follows. In the dose setting phase, the thumbwheel 130 is rotated forward to drive the stopper holder 131 and the operating lever 132 to rotate, and the operating lever 132 drives the sleeve 135 and the torsion spring 136 to rotate, 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. If the dose setting is excessive, the thumbwheel 130 can be rotated backward to adjust the dose. Once the dose is set, the console 1311 of the stop bracket 131 is engaged with the inner ratchet ring 1371 of the torsion spring bracket 137, so that the stop bracket 131, the control lever 132, the sleeve 135 and the torsion spring 136 can be held in this position.In the injection phase, the button assembly 121 of the button mechanism 12 is pressed to push the control lever 132 to move downward in the axial direction, and the control lever 132 drives the sleeve 135 to jointly move downward. As a result, the sleeve 135 is engaged with the driving wheel 141 of the transmission mechanism 14, and at the same time, the control lever 132 is released from the circumferential boundary with respect to the stopper support 131, so that the energy stored in the torsion spring 136 is released. Under the action of the energy released from the torsion spring 136, the sleeve 135 and the control lever 132 jointly rotate in the reverse direction to drive the driving wheel 141 engaged with the sleeve 135 to rotate, and then jointly drive the screw 142 to rotate.When the screw 142 rotates, under 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.

[0123] Specific examples 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. A dose setting mechanism of an injector pen, wherein the dose setting mechanism comprises a thumbwheel, a stopper holder, and a torsion spring holder; the thumbwheel is configured to drive the stopper holder to rotate relative to the torsion spring holder; the stopper holder is provided with a bracket, the torsion spring holder is provided with an inner ratchet ring, and the bracket is engaged with the inner ratchet ring so as to be rotatable in only one dose setting direction; the thumbwheel is provided with an arm portion located outside the bracket;and the thumbwheel is rotatable relative to the stopper support to switch from a first position to a second position, wherein, in the first position, the thumbwheel is allowed to directly drive the stopper support to rotate in the dose setting direction, and the bracket is engaged with the inner ratchet ring so as to be rotatable in only one direction; and in the second position, the arm portion presses the bracket inward in a radial direction, so that the bracket is disengaged from the inner ratchet ring, and the thumbwheel is allowed to directly drive the stopper support to rotate in a direction opposite to the dose setting direction.;

2. The dose setting mechanism according to claim 1, wherein one of the thumb wheel and the stopper holder is provided with a protruding block extending in a radial direction, and the other of the thumb wheel and the stopper holder is provided with a sliding groove extending in a circumferential direction, wherein the protruding block extends into the sliding groove and can rotate circumferentially in the sliding groove; the sliding groove has a first groove wall and a second groove wall in the circumferential direction, the thumb wheel is in the first position when the protruding block abuts the first groove wall, and is in the second position when the protruding block abuts the second groove wall.

3. The dose adjustment mechanism according to claim 2, wherein two or more groups of the protruding blocks and the sliding grooves are provided, which cooperate with each other, and the two or more groups of the protruding blocks and the sliding grooves are uniformly arranged in a circumferential direction of the wheel.

4. The dose setting mechanism of claim 1, wherein a biasing structure is provided between the thumbwheel and the stopper support, and is configured to generate a biasing force to rotate the thumbwheel to the first position in the dose setting direction when the thumbwheel is in the second position.

5. The dose setting mechanism according to claim 4, wherein the biasing structure comprises a limiting rib, and a limiting hole extending in a circumferential direction; one of the limiting rib and the limiting hole is located on the thumbwheel, and the other of the limiting rib and the limiting hole is located on the stopper support, and the limiting rib extends into the limiting hole and is configured such that, when the thumbwheel is in the second position, the limiting rib is pressed by a hole wall of the limiting hole to generate a deformation force for rotating the thumbwheel to the first position.

6. The dose setting mechanism according to any one of claims 1 to 5, wherein the dose setting mechanism further comprises an operating lever, at least a portion of the stopper support is arranged in the thumbwheel, an upper end of the operating lever passes through the stopper support, and a circumferential limiting structure is provided between the operating lever and the stopper support, so that the stopper support can drive the rotation of the operating lever; and the operating lever is movable in an axial direction relative to the stopper support to switch from a position where the operating lever is circumferentially limited relative to the stopper support to a position where the operating lever is released from the circumferential limit relative to the stopper support.

7. A dose setting mechanism according to claim 6, wherein the stopper support comprises a support barrel portion, and the thumbwheel comprises an outer cylindrical member and an inner cylindrical member; wherein the support barrel portion is arranged in the inner cylindrical member, the cylindrical member outer is configured to be in rotatable engagement with an upper pen tube of the injector pen; and the circumferential limiting structure is provided between the control lever and the support barrel portion.

8. The dose adjustment mechanism according to claim 7, wherein the dose adjustment mechanism further comprises a cylinder, a ball, a sleeve, and a torsion spring; the cylinder is arranged outside the operating lever and is inserted into the support barrel portion, a helical channel extending in the axial direction of the operating lever is formed between an inner cylinder wall of the cylinder and an outer lever wall of the operating lever, and the ball is rollably provided in the channel; and the cylinder is connected to the torsion spring holder so as to be circumferentially limited relative to the torsion spring holder; the operating lever is fixed relative to the sleeve; an upper end of the torsion spring is connected to the torsion spring holder, and a lower end of the torsion spring is connected to the sleeve.

9. The dose adjustment mechanism according to claim 8, wherein a plurality of protruding ribs extending outward in the radial direction are provided on an outer sleeve wall of the sleeve near the lower end, and the plurality of protruding ribs are arranged in the circumferential direction of the sleeve to correct the concentricity of the sleeve and the upper pen tube of the injector pen.

10. An injector pen, comprising an upper pen tube, and the dose setting mechanism according to any one of claims 1 to 9 mounted on the upper pen tube.

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