Adjustable-dose automatic injection pen

Abstract

An adjustable-dose automatic injection pen, comprising: a pen housing assembly, which comprises a pen housing (10), a rotatable knob (11) and a pressable button (21); a dose adjustment assembly linked to the knob (11) and configured to increase a set dose when the knob (11) rotates in a first direction and decrease the set dose when the knob (11) rotates in a second direction; an injection assembly linked to the button (21) and configured to implement injection when the button (21) is pressed; and a clutch (6) which is connected between the dose adjustment assembly and the injection assembly and has a first position state and a second position state, wherein when the button (21) is not pressed, the clutch (6) is in the first position state, and the clutch (6) is engaged with the pen housing (10) for limiting, such that the position of the injection assembly remains unchanged; and when the button (21) is pressed, the clutch (6) is in the second position state, and the clutch (6) is disengaged from the pen housing (10) to enable injection of the injection assembly. When the clutch (6) is in the first position state, the clutch (6) is engaged with the pen housing (10) for limiting, such that the position of the injection assembly remains unchanged. In this case, when the dose is adjusted, no injection action is generated, and the injection accuracy can be improved.

Description

An adjustable-dose auto-injection pen

[0001] This application claims priority to Chinese Patent Application No. 202411513778.2, filed on October 28, 2024, entitled "An Adjustable Dosing Automatic Injection Pen", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This invention relates to the field of medical device technology, and more specifically, to an adjustable-dose automatic injection pen. Background Technology

[0003] With the development of medical device technology, adjustable-dose automatic injection pens have been widely used in the medical field.

[0004] However, in existing adjustable-dose auto-injection pens, adjusting the dosage can easily affect the injection components, causing a small amount of liquid to leak from the injection tip of the pen during dosage adjustment, thus affecting injection accuracy.

[0005] Therefore, how to develop an adjustable-dose auto-injection pen that avoids the impact of dosage adjustment on injection is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to provide an adjustable dosage automatic injection pen that can avoid the influence of dosage adjustment on injection and improve injection accuracy.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] An adjustable-dose auto-injection pen, comprising:

[0009] A pen casing assembly includes a pen casing and a rotatable knob and a pressable button respectively disposed on the pen casing;

[0010] A dose adjustment component, linked to the knob, is used to increase the set dose when the knob is rotated in a first direction, and to decrease the set dose when the knob is rotated in a second direction opposite to the first direction;

[0011] An injection component, linked to the button, is used to perform injection when the button is pressed;

[0012] The clutch, connected between the dosage adjustment component and the injection component, has a first position state and a second position state. When the button is not pressed, the clutch is in the first position state, and the clutch engages with the pen shell to limit the position of the injection component. When the button is pressed, the clutch is in the second position state, and the clutch disengages from the pen shell, allowing the clutch to be driven by a driving force to drive the injection component to perform injection.

[0013] Optionally, the dose adjustment component includes:

[0014] A drive rod is axially connected to both the button and the clutch. When the button is not pressed, the drive rod is engaged with the knob, and the clutch is in the first position. When the button is pressed, the drive rod is disengaged from the knob, and the clutch is in the second position.

[0015] The sleeve is axially limited by the drive rod and has a spring plate. The clutch is provided with a first inner one-way tooth. The spring plate extends into the first tooth groove of the first inner one-way tooth, so that the clutch limits the rotation of the sleeve in the second direction.

[0016] The gripper is fixedly connected to the drive rod. When the clutch is in the first position, the gripper drives the sleeve to rotate synchronously when the drive rod rotates in the first direction. When the drive rod rotates in the second direction, the gripper squeezes the spring piece, causing the spring piece to disengage from the first tooth groove, and after the spring piece disengages from the first tooth groove, it drives the sleeve to rotate synchronously in the second direction.

[0017] The dosage indicator can rotate synchronously with the sleeve and can move axially relative to the sleeve, and is threadedly connected to the pen shell.

[0018] Optionally, the pen casing is provided with a limiting portion for abutting against the dose indicator to stop the dose indicator from moving toward the injection end of the injection pen.

[0019] Optionally, the injection assembly includes:

[0020] A push rod is rotatably and synchronously axially movable in the housing;

[0021] The radial wheel is circumferentially limited by the push rod, and the push rod can move axially relative to the radial wheel. The radial wheel can rotate unidirectionally relative to the housing in the second direction. The clutch is always circumferentially limited by the radial wheel.

[0022] A dynamic elastic element, having a preset torsional preload, is installed between the sleeve and the pen shell, so that the sleeve always tends to rotate in the second direction relative to the pen shell.

[0023] Optionally, it also includes:

[0024] A limiter, threadedly connected to the push rod, circumferentially limits the drive rod so that both can rotate synchronously and can move axially along the drive rod. When the drive rod rotates in the first direction, the limiter rotates and moves away from the injection direction along the push rod, so that the axial position of the limiter relative to the push rod corresponds to the set dose of each injection of the dose indicator. When the limiter rotates and moves to the end of the thread at the far end of the push rod, the dose indicator reaches the total dose setting position for the final dose injection.

[0025] Optionally, the dosage indicator is provided with a limiting groove, and the sleeve is provided with a protruding spring. The protruding spring is used to spring into the limiting groove after the dosage indicator abuts against the limiting part, so as to generate a collision and make a sound to indicate that the injection is complete.

[0026] Optionally, the drive rod has at least two end grippers distributed along the same circumference at one end near the injection direction, the outer periphery of the end grippers has a first protrusion and a second protrusion spaced apart along the axial direction, and the outer periphery of the drive rod also has a third protrusion spaced apart from the second protrusion along the axial direction.

[0027] The clutch has a radially inwardly convex inner flange, and the inner flange and the spring plate are respectively disposed in the gap between the first protrusion and the second protrusion, so that the clutch, the sleeve and the drive rod are axially limited and connected.

[0028] The gripper is engaged in the gap between the second protrusion and the third protrusion, and one of the gripper and the drive rod is provided with a first limiting notch, and the other is provided with a first limiting rib that cooperates with the first limiting notch for limiting.

[0029] Optionally, the claw device has a claw sidewall located outside the spring piece, and the thickness of the claw sidewall gradually increases from one side to the other in the circumferential direction, so that when the claw device rotates with the drive rod in the second direction, the claw sidewall squeezes the spring piece, causing the spring piece to disengage from the first tooth groove.

[0030] Optionally, the gripper and the drive rod are integrally formed or are separate structures.

[0031] Optionally, one of the outer periphery of the end of the drive rod away from the injection direction and the knob is provided with a protruding tooth, and the other is provided with a tooth groove. When the button is not pressed, the protruding tooth engages with the tooth groove, and when the button is pressed, the protruding tooth disengages from the tooth groove.

[0032] The drive rod has a fourth protrusion on the inner side of the end away from the injection direction, and the button has an end protrusion. The end protrusion is used to insert into the interior of the drive rod so that the side of the end protrusion away from the injection direction abuts and limits the fourth protrusion towards the injection direction.

[0033] A return spring is provided between the button and the knob to provide an elastic force to the button so that it moves away from the injection direction and resets.

[0034] Optionally, the injection assembly further includes a cam connected to the pen housing;

[0035] The outer periphery of the push rod is provided with two rows of discontinuous helical teeth distributed axially to form a discontinuous first external thread. The cam is provided with a third internal thread for threaded connection with the first external thread, so that when the push rod rotates in the second direction under the cam limit, it moves axially in the injection direction.

[0036] A first limiting guide groove extending axially is provided between the two rows of helical teeth, and the radial wheel is provided with a radial inner protrusion for slidingly engaging with the first limiting guide groove;

[0037] The radial wheel is also provided with a spring arm, and the cam is provided with a second inner one-way tooth. The spring arm cooperates with the second inner one-way tooth so that the radial wheel can rotate relative to the cam in a second direction, and the radial wheel emits a continuous intermittent sound when rotating relative to the cam to indicate injection.

[0038] Optionally, one of the radial wheel and the clutch is provided with a first internal spline, and the other is provided with a first external spline for sliding engagement with the first internal spline, so that the clutch can move axially relative to the radial wheel and that the radial wheel and the clutch are always circumferentially limited.

[0039] Optionally, the limiting part is an inner annular tooth provided on the inner sidewall of the pen shell and distributed circumferentially. The distal end of the inner annular tooth is used to stop and limit the dose indicator. The inner annular tooth is also used to cooperate with a second external spline provided on the outer periphery of the clutch to limit the circumferential movement of the clutch when the clutch moves to the distal position. When the clutch moves to the proximal position, the second external spline disengages from the inner annular tooth.

[0040] Optionally, the pen shell is connected to a cartridge holder at one end near the injection direction. The cartridge holder is used to hold a cartridge. The end of the cartridge holder near the injection direction is used to connect a needle. The end of the cartridge holder away from the injection direction is provided with a raised rib and a second slot. The pen shell is provided with a third limiting notch for engaging with the raised rib. The cam is provided with a first hook for engaging with the second slot. The raised rib protrudes from the third limiting notch to prevent the adjustable dosage auto-injection pen from rolling.

[0041] Optionally, the pen casing further includes:

[0042] The screw cap has two opposing protruding hooks at the end away from the injection direction. The push rod has a neck groove for engaging with the protruding hooks to axially limit the screw cap and the push rod. The end of the screw cap away from the injection direction also has a recess for the conical top of the push rod to extend into. The end of the screw cap near the injection direction is a push surface for contacting the rubber stopper of the cartridge bottle.

[0043] The adjustable-dose automatic injection pen provided by this invention, when the knob is rotated in a first direction, activates the dose adjustment component to increase the set dose; when the knob is rotated in a second direction, it activates the dose adjustment component to decrease the set dose. That is, the set dose can be flexibly adjusted, either increasing or decreasing, thus achieving bidirectional dose adjustment for user convenience. Furthermore, pressing the button activates the injection component to initiate injection. Additionally, when the button is not pressed, the clutch is in its first position, where it engages with the pen housing to maintain a fixed position. This prevents the clutch from rotating, thus keeping the injection component in a fixed position. Therefore, when the button is not pressed, dose adjustment can be achieved by rotating the knob while keeping the injection component in a fixed position, preventing injection and avoiding liquid leakage that could affect injection accuracy. When injection is needed, the button can be pressed to put the clutch in the second position. At this time, the clutch is disengaged from the pen shell, and the clutch is driven by the driving force to drive the injection component to achieve injection. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0045] Figure 1 is a schematic diagram of the internal structure of the adjustable dose automatic injection pen provided in a specific embodiment of the present invention;

[0046] Figure 2 is a schematic diagram of the internal structure of the adjustable-dose auto-injection pen from another perspective.

[0047] Figure 3 is an exploded view of the adjustable-dose auto-injection pen.

[0048] Figure 4 is an exploded view of the adjustable-dose auto-injection pen;

[0049] Figure 5 is a schematic diagram of the external structure of the adjustable-dose auto-injection pen;

[0050] Figure 6 is a schematic diagram of the structure when the knob is rotated in the first direction to increase the set dose;

[0051] Figure 7 is a schematic diagram of the internal structure of the adjustable dose auto-injection pen when the button is not pressed;

[0052] Figure 8 is a schematic diagram of the combination of the drive lever and the knob;

[0053] Figure 9 is a schematic diagram of the assembly structure of the drive rod, the gripper, the sleeve, and the dose indicator;

[0054] Figure 10 is a schematic diagram of the fit between the dose indicator and the pen shell;

[0055] Figure 11 is a schematic diagram of the structure when the drive rod rotates in the second direction (before the spring retracts);

[0056] Figure 12 is a schematic diagram of the structure when the clutch is in the far end position;

[0057] Figure 13 is a schematic diagram of the internal structure of the adjustable dose auto-injection pen when the button is pressed;

[0058] Figure 14 is a schematic diagram of the clutch when it is in the proximal position;

[0059] Figure 15 is a schematic diagram of the structure in which the sleeve drives the clutch, radial wheel and push rod to rotate in the second direction;

[0060] Figure 16 is a schematic diagram of the internal structure of the adjustable-dose auto-injection pen when the maximum dose is achieved in a single injection.

[0061] Figure 17 is a schematic diagram of the structure when the 0 mark of the dose indicator is aligned with the observation window of the pen casing;

[0062] Figure 18 is a schematic diagram of the structure when the protruding spring of the sleeve is inserted into the limiting groove of the dose indicator when the dose indicator is in the proximal position.

[0063] Figure 19 is a schematic diagram of the limiter;

[0064] Figure 20 is a schematic diagram of the structure when the limiter and the push rod are in conjunction;

[0065] Figure 21 is a schematic diagram of the structure when the limiter and the drive rod are in cooperation;

[0066] Figure 22 is a schematic diagram of the dose indicator;

[0067] Figure 23 is a schematic diagram of the assembly of the dose indicator and the sleeve;

[0068] Figure 24 is a schematic diagram of the assembly of the dose indicator and the pen shell;

[0069] Figure 25 is a schematic diagram of the drive rod structure;

[0070] Figure 26 is a schematic diagram of the clutch structure;

[0071] Figure 27 is a schematic diagram of the clamping device;

[0072] Figure 28 is a schematic diagram of the sleeve structure;

[0073] Figure 29 is a schematic diagram of the assembled structure of the drive rod, clutch, sleeve and gripper;

[0074] Figure 30 is a structural schematic diagram of Figure 29 from another perspective;

[0075] Figure 31 is a schematic diagram of the fit relationship between the drive rod, clutch, sleeve and clamp after assembly;

[0076] Figure 32 is a schematic diagram of a structure in which the drive rod and the gripper are integrally machined.

[0077] Figure 33 is a schematic diagram of the structure after the drive rod and knob are assembled;

[0078] Figure 34 is a schematic diagram of the structure after the knob and pen shell are assembled;

[0079] Figure 35 is a schematic diagram of the assembled drive rod, knob, button and return spring;

[0080] Figure 36 is a schematic diagram of the push rod structure;

[0081] Figure 37 is a schematic diagram of the cam structure;

[0082] Figure 38 is a schematic diagram of the structure after the cam and push rod are assembled;

[0083] Figure 39 is a schematic diagram of the radial wheel;

[0084] Figure 40 is a schematic diagram of the structure after the radial wheel and push rod are assembled;

[0085] Figure 41 is a schematic diagram of the structure after the cam and radial wheel are assembled;

[0086] Figure 42 is a schematic diagram of the structure after the radial wheel and clutch are assembled;

[0087] Figure 43 is a schematic diagram of the pen casing structure;

[0088] Figure 44 is a schematic diagram of the structure when the pen shell and clutch are assembled and the clutch is in the near-end position;

[0089] Figure 45 is an exploded view of the pen casing, cartridge bottle, refill holder, needle, and pen cap;

[0090] Figure 46 is a schematic diagram of the pen refill holder;

[0091] Figure 47 is a schematic diagram of the internal structure of the pen casing;

[0092] Figure 48 is a schematic diagram of the pen cap structure;

[0093] Figure 49 is a schematic diagram of the structure after the pen cap and pen refill holder are assembled;

[0094] Figure 50 is a schematic diagram of the screw fastener structure;

[0095] Figure 51 is a schematic diagram of the structure after the screw fastener and push rod are assembled;

[0096] Figure 52 is a schematic diagram of the elastic dynamic component;

[0097] Figure 53 is a schematic diagram of the shell cover structure;

[0098] Figure 54 is a schematic diagram of the assembled pen shell, cap, and elastic power component.

[0099] Figure 55 is a schematic diagram of the structure after the elastic dynamic component and the sleeve are assembled.

[0100] Reference numerals: 1-Needle; 2-Cassette bottle; 3-Cassette bottle stopper; 4-Switch; 41-Recess; 42-Protrusion hook; 43-Propulsion plane; 5-Radial wheel; 51-Radial inner protrusion; 52-First external spline; 53-Spring arm; 6-Clutch; 61-First internal spline; 62-Second external spline; 63-First inner one-way tooth; 64-Inner flange; 7-Claw clamp; 71-Claw clamp sidewall; 72-First limiting notch; 8-Power elastic element; 81-First bend; 82-Second bend; 9- Dosage indicator; 91-Digital printing section; 92-Limiting groove; 93-Second limiting rib; 94-Second external thread; 10-Pen shell; 101-First slot; 102-Limiting part; 103-Second internal thread; 104-Observation window; 105-Annular flange; 106-Second limiting notch; 107-Fifth slot; 108-Third limiting notch; 11-Knob; 111-Groove; 112-Annular groove; 12-Return spring; 13-Pen cap; 131-Groove; 132-Single side Positioning part; 14-Pen refill holder; 141-Threaded structure; 142-Protrusion; 143-Raised rib; 144-Second slot; 145-Through hole; 15-Cam; 151-Second inner one-way tooth; 152-First hook; 153-Second hook; 154-Third internal thread; 16-Limiter; 161-Arrow rib; 162-First internal thread; 17-Sleeve; 171-Spring; 172-Raised spring; 173-Second limiting guide groove; 174-Fourth slot; 18-Push Rod; 181-Helical tooth; 182-First limiting guide groove; 183-Neck recess; 184-Conical top; 19-Drive rod; 191-End gripper; 192-First protrusion; 193-Second protrusion; 194-Third protrusion; 195-First limiting rib; 196-Protruding tooth; 197-Fourth protrusion; 198-Inner long groove; 20-Shell cover; 201-Third slot; 202-Radial flange; 203-Third hook; 21-Button; 211-End convex circle. Detailed Implementation

[0101] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0102] The core of this invention is to provide an adjustable-dose automatic injection pen that can adjust the set dose in both directions.

[0103] Please refer to Figures 1 to 5. This embodiment of the invention provides an adjustable-dose automatic injection pen, including a pen housing assembly, a dose adjustment assembly, an injection assembly, and a clutch 6. The pen housing assembly includes a pen housing 10 and a rotatable knob 11 and a pressable button 21 respectively disposed on the pen housing 10. The dose adjustment assembly is linked to the knob 11, used to increase the set dose when the knob 11 is rotated in a first direction and decrease the set dose when the knob 11 is rotated in a second direction opposite to the first direction. The injection assembly is linked to the button 21, used to perform injection when the button 21 is pressed. The clutch 6 is connected between the dose adjustment assembly and the injection assembly, and the clutch 6 has a first position state and a second position state. When the button 21 is not pressed, the clutch 6 is in the first position state, and the clutch 6 cooperates with the pen housing 10 to limit the position of the injection assembly. When the button 21 is pressed, the clutch 6 is in the second position state, the clutch 6 is disengaged from the pen housing 10, and the clutch 6 is driven by a driving force to drive the injection assembly to perform injection.

[0104] This adjustable-dose automatic injection pen, when the knob 11 is rotated in the first direction, activates the dose adjustment component to increase the set dose; when the knob 11 is rotated in the second direction, it activates the dose adjustment component to decrease the set dose. That is, the set dose can be flexibly adjusted, either increasing or decreasing, thus achieving bidirectional dose adjustment for user convenience. Furthermore, pressing the button 21 activates the injection component to initiate injection. Additionally, when the button 21 is not pressed, the clutch 6 is in the first position, where it engages with the pen housing 10 to maintain a fixed position. This prevents the clutch 6 from rotating, thus keeping the injection component in a fixed position. Therefore, when the button 21 is not pressed, the dose can be adjusted by rotating the knob 11 while keeping the injection component in a fixed position, preventing injection and avoiding liquid leakage that could affect injection accuracy. When injection is required, button 21 can be pressed to put clutch 6 in the second position. At this time, clutch 6 is disengaged from pen shell 10, and clutch 6 is driven by driving force to drive the injection component to achieve injection.

[0105] It should be noted that this embodiment does not limit the specific structure of the dose adjustment component, as long as it can achieve bidirectional dose adjustment.

[0106] In some embodiments, the dose adjustment assembly includes a drive rod 19, a sleeve 17, a gripper 7, and a dose indicator 9. The drive rod 19 is axially connected to the button 21 and the clutch 6, respectively. When the button 21 is not pressed, the drive rod 19 is engaged with the knob 11, and the clutch 6 is in a first position. When the button 21 is pressed, the drive rod 19 is disengaged from the knob 11, and the clutch 6 is in a second position. The sleeve 17 is axially limited to the drive rod 19. The sleeve 17 has a spring plate 171. The clutch 6 is provided with a first inner one-way tooth 63. The spring plate 171 extends into the first tooth groove of the first inner one-way tooth 63, thereby engaging the clutch. Device 6 limits the rotation of sleeve 17 in the second direction; the gripper 7 is fixedly connected to drive rod 19. When the clutch is in the first position, when drive rod 19 rotates in the first direction, gripper 7 drives sleeve 17 to rotate synchronously. When drive rod 19 rotates in the second direction, gripper 7 squeezes spring 171, causing spring 171 to disengage from the first tooth groove, and after spring 171 disengages from the first tooth groove, it drives sleeve 17 to rotate synchronously in the second direction; the dose indicator 9 can rotate synchronously with sleeve 17, and the dose indicator 9 can move axially relative to sleeve 17, and the dose indicator 9 is threadedly connected to pen shell 10.

[0107] It should be noted that, for ease of description, in the embodiments of the present invention, the proximal end refers to the end near the injection tip of the adjustable-dose auto-injector pen, that is, the end near the injection direction; the distal end refers to the end away from the injection tip of the adjustable-dose auto-injector pen, that is, the end away from the injection direction; the axial direction refers to the length direction of the adjustable-dose auto-injector pen, and the circumferential direction refers to the circumferential direction of the adjustable-dose auto-injector pen. Furthermore, in the embodiments of the present invention, the first direction and the second direction refer to two opposite directions. For example, the first direction is clockwise, which is the direction of dose increase; the second direction is counterclockwise, which is the direction of dose decrease. Simultaneously, the second direction is also the rotation direction of the injection component during injection.

[0108] It should be noted that the clutch 6 and the sleeve 17 are axially fixed relative to the drive rod 19, that is, the clutch 6 and the sleeve 17 can move axially synchronously with the drive rod 19, while the clutch 6 and the sleeve 17 can rotate relative to the drive rod 19 in the circumferential direction; the gripper 7 is fixedly connected to the drive rod 19, therefore, the gripper 7 can move axially synchronously with the drive rod 19 and can rotate circumferentially synchronously with the drive rod 19.

[0109] It is understandable that the knob 11, drive lever 19, sleeve 17, gripper 7 and dose indicator 9 work together to form a dose adjustment assembly, so that the set dose of the adjustable dose auto-injection pen can be adjusted for a single injection. When the knob 11 is rotated in the first direction, the set dose increases, and when the knob 11 is rotated in the second direction, the set dose decreases.

[0110] Specifically, when it is necessary to adjust and increase the set dosage, rotate knob 11 in the first direction (as shown in Figure 6). Note that button 21 is not pressed at this time (as shown in Figure 7). At this time, drive rod 19 engages with knob 11 (as shown in Figure 8), causing knob 11 to drive drive rod 19 to rotate in the first direction. Drive rod 19 drives gripper 7 to rotate synchronously, and gripper 7 drives sleeve 17 to rotate synchronously (clutch 6 and sleeve 17 are connected by the first inner one-way tooth 63 and spring plate 171, and clutch 6 engages with sleeve 17 in the second direction). The sleeve 17 is limited in rotation but not in rotation in the first direction. Therefore, when the clutch 6 is in the first position, the sleeve 17 can rotate relative to the clutch 6 in the first direction. The sleeve 17 drives the dose indicator 9 to rotate synchronously (as shown in Figure 9), so that the dose indicator 9 makes a spiral motion relative to the pen shell 10 (as shown in Figure 10). That is, the dose indicator 9 rotates in the first direction while making axial movement, so that the dose indicator 9 is axially displaced away from the injection direction, thereby increasing the set dose.

[0111] Please refer to Figure 11. When it is necessary to adjust and reduce the set dose, rotate the knob 11 in the second direction. Note that the button 21 is not pressed at this time. At this time, the drive rod 19 engages with the knob 11, causing the knob 11 to drive the drive rod 19 to rotate in the second direction. The drive rod 19 drives the gripper 7 to rotate synchronously. The gripper 7 causes the spring 171 of the sleeve 17 to retract, thereby disengaging the sleeve 17 from the clutch 6. Therefore, after the spring 171 retracts, the gripper 7 can drive the sleeve 17 to rotate synchronously in the second direction. The sleeve 17 drives the dose indicator 9 to rotate synchronously, causing the dose indicator 9 to make a spiral motion relative to the pen shell 10. That is, the dose indicator 9 rotates in the second direction while making axial movement, thereby causing the dose indicator 9 to generate axial displacement towards the injection direction, achieving the purpose of reducing the set dose.

[0112] During the movement of the knob 11 driving the drive rod 19 in the first and second directions, the button 21 is not pressed. At this time, please refer to Figure 12. The clutch 6 is in the far end position, that is, the clutch 6 is in the first position state. At this time, the clutch 6 is engaged with the pen shell 10. Under the limit of the pen shell 10, the clutch 6 cannot rotate with the drive rod 19, so that the injection component remains in a fixed position. Therefore, during the adjustment of the set dose, whether the set dose increases or decreases, the injection component will not produce any axial displacement, so no injection activity will occur.

[0113] After the dosage setting is completed, when injection is required, press button 21 (as shown in Figure 13). Button 21 drives the drive rod 19 to move axially towards the proximal end, disengaging the drive rod 19 from the knob 11. Simultaneously, the drive rod 19 drives the clutch 6, sleeve 17, and gripper 7 to move axially towards the proximal end. Refer to Figure 14 to move the clutch 6 to the proximal position, placing the clutch 6 in the second position state. This disengages the clutch 6 from the pen housing 10, releasing the circumferential limiting effect of the pen housing 10 on the clutch 6. At this time, the clutch 6 can rotate freely to avoid interfering with the operation of the injection assembly, allowing the injection assembly to inject.

[0114] This demonstrates that the adjustable-dose automatic injection pen allows for flexible adjustment of the set dose, enabling both increases and decreases in the set dose, thus achieving bidirectional adjustment and facilitating user convenience. When decreasing the set dose, this embodiment utilizes the rotation of the gripper 7 to first compress and retract the spring 171 of the sleeve 17, disengaging the spring 171 from the clutch 6. After the spring 171 retracts, the gripper 7 drives the sleeve 17 to rotate in the second direction. That is, with the spring 171 retracted, the sleeve 17 rotates relative to the clutch 6 in the second direction, reducing the resistance generated by the clutch 6 when the sleeve 17 rotates in the second direction. This results in less resistance during the reduction of the set dose, leading to a smoother and more stable adjustment force for decreasing the set dose. Furthermore, when increasing the set dosage, the drive rod 19 rotates in the first direction, causing the gripper 7 to drive the sleeve 17 to rotate synchronously in the first direction. At this time, the spring 171 engages with the clutch 6, and the two can only rotate synchronously in the second direction. Therefore, when the clutch 6 is limited by the pen shell 10, the sleeve 17 cannot rotate in the second direction. That is, during the process of increasing the set dosage, the sleeve 17 can be prevented from rotating back in the second direction, thereby ensuring the accuracy of the adjustment of the set dosage.

[0115] Furthermore, the above embodiments do not limit the specific structure of the injection component, as long as the injection component can achieve injection.

[0116] In some embodiments, the injection assembly includes a push rod 18, a radial wheel 5, and a dynamic elastic element 8. The push rod 18 is rotatably and synchronously axially movable in the housing 10, for example, the push rod 18 is threadedly connected to the housing 10. The radial wheel 5 is circumferentially limited to the push rod 18, and the push rod 18 is axially movable relative to the radial wheel 5. The radial wheel 5 is unidirectionally rotated relative to the housing 10 in a second direction. The clutch 6 is always circumferentially limited to the radial wheel 5. The dynamic elastic element 8 is installed between the sleeve 17 and the pen housing 10 with a preset torsional preload, so that the sleeve 17 always has a tendency to rotate relative to the pen housing 10 in the second direction.

[0117] Understandably, during the movement of the knob 11 driving the drive rod 19 in the second and first directions, the button 21 is not pressed. At this time, the clutch 6 is in the first position, and the clutch 6 is engaged with the pen shell 10. Under the limitation of the pen shell 10, the clutch 6 cannot rotate with the drive rod 19. The clutch 6 and the radial wheel 5 are always circumferentially limited, and they rotate or stop synchronously. Moreover, the radial wheel 5 and the push rod 18 are circumferentially limited. Therefore, when the clutch 6 is engaged with the pen shell 10, the push rod 18 cannot rotate. Since the push rod 18 is threadedly connected to the shell 10, the push rod 18 moves axially while rotating. Therefore, when the push rod 18 cannot rotate, the axial position of the push rod 18 is also restricted and cannot move. That is, during the dose setting adjustment process, whether the set dose increases or decreases, the push rod 18 will not produce any axial displacement, and therefore no injection activity will occur.

[0118] Additionally, during injection, pressing button 21 (as shown in Figure 13) causes the drive rod 19 to synchronously move the clutch 6, sleeve 17, and gripper 7 axially toward the injection end. Referring to Figure 14, this moves the clutch 6 to the second position, disengaging it from the pen housing 10 and releasing the pen housing 10's circumferential limiting effect on the clutch 6. At this time, under the action of the power elastic element 8, as shown in Figure 15, the sleeve 17 rotates in the first direction. The sleeve 17 drives the clutch 6 to rotate synchronously, and the clutch 6 drives the radial wheel 5 to rotate synchronously relative to the pen housing 10 in the first direction. This, in turn, causes the radial wheel 5 to drive the push rod 18 to rotate synchronously. Since the push rod 18 is threadedly connected to the pen housing 10, it rotates while simultaneously moving axially toward the injection end, generating axial displacement and thus realizing the injection process (as shown in Figure 16). During this process, the sleeve 17 drives the dose indicator 9 to rotate synchronously, causing the dose indicator 9 to perform a helical motion relative to the pen housing 10. That is, the dose indicator 9 rotates along the first direction while simultaneously moving axially.

[0119] To facilitate limiting the movement of the dosage indicator 9 toward the injection end, in some embodiments, the pen housing 10 is provided with a limiting part 102 for abutting against the dosage indicator 9 to stop its movement toward the injection end. That is, when the dosage indicator 9 rotates along the first direction while moving axially, it causes axial displacement towards the limiting part 102 until it abuts against the limiting part 102 of the pen housing 10. Under the limiting of the limiting part 102, the dosage indicator 9 stops rotating, thereby stopping both the sleeve 17 and the push rod 18 from rotating, indicating that the injection is complete and the set dosage of injection solution has been injected. It is understood that during this process, the sleeve 17 will drive the gripper 7 to rotate together in the first direction, causing the drive rod 19 to rotate synchronously in the first direction. At this time, the drive rod 19 is separated from the knob 11 to prevent the knob 11 from affecting the rotation of the drive rod 19. As can be seen, in this embodiment, when injection is performed by moving the push rod 18 axially, the dose indicator 9 and the pen shell 10 limit the completion of a single injection. When the set dose is adjusted by adjusting the axial position of the dose indicator 9, the axial position of the push rod 18 remains unchanged. Therefore, multiple injections can be achieved by adjusting the dose indicator 9 multiple times, thereby achieving multi-dose injection.

[0120] Additionally, referring to Figure 16, in order to limit the final dose of the last injection by the syringe, in some embodiments, the adjustable dose auto-injection pen also includes a limiter 16. The limiter 16 is threadedly connected to the push rod 18, and the limiter 16 and the drive rod 19 are circumferentially limited so that they can rotate synchronously. The limiter 16 can also move axially along the drive rod 19. When the drive rod 19 rotates in a first direction, the limiter 16 rotates and moves away from the injection direction along the push rod 18, so that the axial position of the limiter 16 relative to the push rod 18 corresponds to the set dose of each injection by the dose indicator 9. When the limiter 16 rotates and moves to the end of the thread of the push rod 18, the dose indicator 9 reaches the total dose setting position of the final dose injection. In other words, when the push rod 18 is fixed, the limiter 16 will rotate synchronously with the rotation of the drive rod 19. That is, during the dose adjustment process, the limiter 16 will move axially on the push rod 18. When the dose is increased, the limiter 16 moves away from the injection end, and when the dose is decreased, the limiter 16 moves closer to the injection end. In this embodiment, the distal position of the limiter 16 limits the total set dose of the final injection of the syringe. It can be understood that when the drive rod 19 is rotated in the first direction to increase the set dose, the limiter 16 rotates relative to the push rod 18 and moves toward the distal end of the push rod 18. When a single injection ends, the limiter 16 will stop at the position corresponding to the last adjusted dose of the injection, that is, at the axial position relative to the push rod 18. When the syringe is almost finished using and the last dose of the injection is adjusted, the limiter 16 will reach the distal end of the thread. When the limiter 16 reaches the end of the thread at the distal end of the push rod 18, the limiter 16 can no longer rotate. Since the limiter 16 and the drive rod 19 are circumferentially limited, the drive rod 19 can no longer rotate in the first direction, thereby limiting the distal position of the dose indicator 9, that is, limiting the maximum dose of the dose indicator 9. Additionally, it is understandable that when button 21 is pressed, and the push rod 18 rotates while moving axially towards the proximal end for injection, the limiter 16 will move synchronously with the push rod 18. Furthermore, the position of the proximal end of the limiter 16 is limited by the radial wheel 5. That is, when the injection is completed, the push rod 18 moves to the proximal position and stops advancing. At this time, the limiter 16 abuts against the radial wheel 5, thus playing a limiting role.

[0121] Referring to Figures 19, 20, and 21, in some embodiments, the inner circumferential surface of the limiter 16 is provided with a first internal thread 162 for threaded connection with the first external thread of the push rod 18, so that the limiter 16 must simultaneously rotate circumferentially when it makes axial movement on the push rod 18, thereby enabling the limiter 16 to move axially on the push rod 18 as the drive rod 19 rotates. In other embodiments, the outer side of the limiter 16 is provided with an arrow rib 161 symmetrical about the axis of the limiter 16, and the inner side of the drive rod 19 is provided with a symmetrical inner elongated groove 198 extending along its axial direction, with the arrow rib 161 slidingly engaged with the inner elongated groove 198. That is, in this embodiment, the sliding engagement between the arrow rib 161 and the inner elongated groove 198 limits the axial movement of the limiter 16 relative to the drive rod 19, and allows it to rotate synchronously with the drive rod 19, resulting in a simple structure that is easy to implement.

[0122] When adjusting the set dosage, to facilitate user observation of the set dosage at any time, please refer to Figure 17. In some embodiments, the dosage indicator 9 is provided with a digital printing section 91, and the pen shell 10 is provided with an observation window 104. The observation window 104 is used to observe the dosage value of the part of the digital printing section 91 aligned with the observation window 104. That is, when adjusting the set dosage, the dosage indicator 9 is rotated so that different parts of the digital printing section 91 are aligned with the observation window 104. The dosage value aligned with the observation window 104 is observed to determine whether the required set dosage has been reached. When the required set dosage is reached, the rotation of the knob 11 can be stopped in time. It should be noted that the observation window 104 can be an exposed through hole or a transparent part provided at the through hole.

[0123] It should be noted that, in the initial state, the 0 mark of the dose indicator 9 is aligned with the observation window 104 (as shown in Figure 17). At this time, the dose indicator 9 is in contact with the limiting part 102 of the pen shell 10 (as shown in Figure 18). When the injection dose is set by rotating the knob 11, the dose indicator 9 rotates while moving away from the limiting part 102 of the pen shell 10 until the required injection dose is reached. At this time, the set dose scale is aligned with the observation window 104, the knob 11 is stopped, and then the button 21 is pressed to inject. When the injection is completed, the dose indicator 9 is in contact with the limiting part 102 of the pen shell 10. At this time, the 0 mark of the dose indicator 9 is aligned with the observation window 104.

[0124] Please refer to Figures 22 and 23. To more intuitively remind the user that the injection is complete, in some embodiments, the dosage indicator 9 is provided with a limiting groove 92, and the sleeve 17 is provided with a raised spring 172. The raised spring 172 is used to spring into the limiting groove 92 after the dosage indicator 9 abuts against the limiting part 102 (see Figure 18) to generate a collision sound, indicating that the injection is complete. That is, when each injection ends, the dosage indicator 9 will move to a position where its proximal end abuts against the limiting part 102 of the pen shell 10. At this time, the raised spring 172 of the sleeve 17 will spring into the limiting groove 92, thereby emitting an injection completion prompt sound, giving the user the most direct reaction that the injection is complete, making it easy for the user to confirm that the injection is complete. This structure is simple and does not require excessive size control or complex product shape.

[0125] Furthermore, referring to Figure 23, in order to connect the dose indicator 9 to the sleeve 17, in some embodiments, one of the outer side of the sleeve 17 and the inner side of the dose indicator 9 is provided with a second limiting rib 93 extending axially, and the other is provided with a second limiting guide groove 173 for sliding engagement with the second limiting rib 93. That is, this embodiment utilizes the engagement of the second limiting rib 93 and the second limiting guide groove 173 to achieve circumferential limiting of the sleeve 17 and the dose indicator 9, so that the dose indicator 9 and the sleeve 17 can rotate synchronously. At the same time, through the sliding engagement of the second limiting rib 93 and the second limiting guide groove 173, the dose indicator 9 can move axially relative to the sleeve 17 during synchronous rotation with the sleeve 17.

[0126] Additionally, referring to Figure 24, in order to connect the dose indicator 9 to the pen housing 10, in some embodiments, the pen housing 10 is provided with a second internal thread 103, and the outer periphery of the dose indicator 9 is provided with a second external thread 94 for threaded connection with the second internal thread 103, so that the dose indicator 9 can move axially and rotate circumferentially within the pen housing 10 with a specific pitch.

[0127] It should be noted that the above embodiments do not limit the specific connection methods of the drive rod 19 with the clutch 6, the sleeve 17 and the gripper 7, as long as the connection of the drive rod 19 with the clutch 6, the sleeve 17 and the gripper 7 meets the corresponding connection requirements.

[0128] Referring to Figures 25 to 29, in some embodiments, the proximal end of the drive rod 19 is provided with at least two end grippers 191 distributed along the same circumference. The outer periphery of the end grippers 191 is provided with a first protrusion 192 and a second protrusion 193 spaced apart along the axial direction. The outer periphery of the drive rod 19 is also provided with a third protrusion 194 spaced apart from the second protrusion 193 along the axial direction. The clutch 6 is provided with a radially inwardly protruding inner flange 64. The inner flange 64 and the spring piece 171 of the sleeve 17 are respectively provided in the gap between the first protrusion 192 and the second protrusion 193, so that the clutch 6, the sleeve 17 and the drive rod 19 are axially limited and connected. The clamping claw 7 is locked in the gap between the second protrusion 193 and the third protrusion 194. One of the clamping claw 7 and the drive rod 19 is provided with a first limiting notch 72, and the other is provided with a first limiting rib 195 that cooperates with the first limiting notch 72 for limiting. In other words, in this embodiment, the clutch 6, sleeve 17, and drive rod 19 are connected together by the end gripper 191 engaging with the first protrusion 192 and the second protrusion 193, so that the axial positions of the clutch 6, sleeve 17, and drive rod 19 are relatively fixed, and the clutch 6 and sleeve 17 can rotate circumferentially relative to the drive rod 19 respectively. In addition, the second protrusion 193 and the third protrusion 194 are used to fix the axial position of the gripper 7 and the drive rod 19, and the first limiting rib 195 engaging with the first limiting notch 72 is used to fix the circumferential position of the gripper 7 and the drive rod 19, so that the gripper 7 and the drive rod 19 are completely fixed, and the gripper 7 can rotate together with the drive rod 19.

[0129] Further, referring to Figures 30 and 31, in some embodiments, the clutch 6 is provided with a first inner one-way tooth 63 for engaging with the spring plate 171 of the sleeve 17, and the claw retainer 7 is provided with a claw sidewall 71 located outside the spring plate 171. The thickness of the claw sidewall 71 gradually increases from one side to the other in the circumferential direction, so that when the claw retainer 7 rotates in the second direction with the drive rod 19, the claw sidewall 71 squeezes the spring plate 171, causing the spring plate 171 to retract. That is, in this embodiment, when the spring plate 171 extends outward, the spring plate 171 engages with the first inner one-way tooth 63, thereby enabling the sleeve 17 and the clutch 6 to rotate synchronously in the circumferential direction. In addition, by utilizing the thickness variation of the sidewall 71 of the claw, when the claw device 7 rotates along the second direction with the drive rod 19, the sidewall 71 of the claw gradually squeezes the spring piece 171 to make it retract. When the spring piece 171 retracts, the spring piece 171 separates from the first inner one-way tooth 63, so that the rotation of the sleeve 17 is not restricted by the clutch 6.

[0130] Furthermore, referring to Figure 33, considering ease of assembly, in some embodiments, the gripper 9 and the drive rod 5 are integrally formed. That is, in this embodiment, the structure of the gripper 9 is integrated onto the drive rod 5, making the gripper 9 and the drive rod 5 a single unit. This avoids the need for separate assembly of the gripper 9 and the drive rod 5 during assembly, reducing assembly steps, simplifying the assembly process, facilitating the assembly of the injection device, and improving assembly efficiency.

[0131] Of course, as shown in Figures 25, 27, and 29-31, the specific connection structure when the gripper 9 and the drive rod 5 are separate structures is given.

[0132] Furthermore, the specific connection method between the knob 11 and the drive rod 19 is not limited in the above embodiments. Please refer to Figure 33. In some embodiments, one of the outer periphery of the distal end of the drive rod 19 and the knob 11 is provided with a protruding tooth 196, and the other is provided with a tooth groove 111. When the button 21 is not pressed, the protruding tooth 196 engages with the tooth groove 111. When the button 21 is pressed, the protruding tooth 196 disengages from the tooth groove 111. It can be understood that when the drive rod 19 is in the distal position, the button 21 is not pressed, and the protruding tooth 196 engages with the tooth groove 111, so that the drive rod 19 and the knob 11 are engaged, thereby enabling the drive rod 19 and the knob 11 to rotate synchronously. That is, when the knob 11 is turned, the drive rod 19 can be rotated, thereby adjusting the dosage. When button 21 is pressed, causing the drive lever 19 to move from the distal position to the proximal position, the protruding tooth 196 disengages from the tooth groove 111, allowing the drive lever 19 and the knob 11 to rotate relative to each other, so that the knob 11 will not rotate synchronously when the drive lever 19 rotates.

[0133] Furthermore, considering the specific arrangement of the knob 11 on the pen shell 10, please refer to Figure 34. In some embodiments, one of the knob 11 and the pen shell 10 is provided with an annular groove 112, and the other is provided with an annular flange 105 for sliding engagement with the annular groove 112. That is, by utilizing the engagement between the annular flange 105 and the annular groove 112, the axial positioning of the knob 11 and the pen shell 10 is achieved, and by allowing the annular flange 105 and the annular groove 112 to slide relative to each other, the knob 11 can rotate freely on the pen shell 10.

[0134] Furthermore, the specific connection method between the button 21 and the drive rod 19 is not limited in the above embodiments. Please refer to Figure 35. In some embodiments, a fourth protrusion 197 is provided on the inner side of the distal end of the drive rod 19, and an end protrusion 211 is provided on the proximal end of the button 21. The end protrusion 211 is used to insert into the interior of the distal end of the drive rod 19, so that the side of the end protrusion 211 facing the distal end and the side of the fourth protrusion 197 facing the proximal end can abut and limit the button. That is to say, in this embodiment, the side of the end protrusion 211 of the button 21 facing the distal end abuts and limits the button 21 by abutting and limiting the fourth protrusion 197 of the drive rod 19, thereby restricting the axial position of the button 21 and preventing the button 21 from disengaging from the drive rod 19.

[0135] Further, referring to Figure 35, in some embodiments, a return spring 12 is provided between the button 21 and the knob 11. The return spring 12 provides an elastic force to the button 21 to move it to its distal end, so that the button 21 returns to its distal position. That is, when the button 21 is not pressed, the button 21 maintains its distal position under the action of the return spring 12. When the button 21 is pressed, the return spring 12 is compressed. When the button 21 is released, the elastic force of the return spring 12 causes the button 21 to return to its distal position. During this process, the button 21 drives the drive rod 19 to engage with the knob 11.

[0136] Additionally, referring to Figures 36 to 42, to facilitate the threaded connection between the push rod 18 and the pen housing 10, and the unidirectional rotation of the radial wheel 5 relative to the pen housing 10, in some embodiments, the injection assembly further includes a cam 15 connected to the pen housing 10; the outer periphery of the push rod 18 is provided with two rows of axially distributed helical teeth 181 to form a discontinuous first external thread, and the cam 15 is provided with a third internal thread 154 for engaging with the first external thread, so that when the push rod 18 rotates in the second direction under the limiting position of the cam 15, it moves axially towards the proximal end. Further, in some embodiments, a first limiting guide groove 182 extending axially is provided between the two rows of helical teeth 181, and the radial wheel 5 is provided with a radial inner protrusion 51 for slidingly engaging with the first limiting guide groove 182. In other words, this embodiment utilizes the cooperation between the radial inner protrusion 51 and the first limiting guide groove 182 to achieve circumferential limiting of the radial wheel 5 and the push rod 18, allowing the radial wheel 5 to rotate synchronously with the push rod 18, and simultaneously enabling the radial wheel 5 to move axially relative to the push rod 18. Further, in some embodiments, the radial wheel 5 is provided with a spring arm 53, and the cam 15 is provided with a second inner one-way tooth 151. The spring arm 53 cooperates with the second inner one-way tooth 151, allowing the radial wheel 5 to rotate relative to the cam 15 in a second direction. When the radial wheel 5 rotates relative to the cam 15, it emits a continuous intermittent sound, which indicates that injection is in progress. When the radial wheel 5 stops rotating, the continuous intermittent sound ends, signifying that the injection has stopped. Therefore, this also indicates whether the injection is complete.

[0137] Furthermore, in some embodiments, the cam 15 is provided with a stop limiting portion 102, which is located on the proximal end side of the second inner one-way tooth 151, and is used to axially limit the proximal end of the radial wheel 5. Furthermore, in some embodiments, one of the radial wheel 5 and the clutch 6 is provided with a first internal spline 61, and the other is provided with a first external spline 52 for sliding engagement with the first internal spline 61, so that the clutch 6 can move axially relative to the radial wheel 5, and that the radial wheel 5 and the clutch 6 are always circumferentially limited. That is, the radial wheel 5 and the clutch 6 can slide relative to each other axially, but they are never separated, so that the radial wheel 5 and the clutch 6 always remain synchronously rotating or synchronously stopping.

[0138] In addition, to achieve the connection between the cam 15 and the pen shell 10, please refer to Figures 41 and 43. In some embodiments, the cam 15 is provided with a second hook 153, and the pen shell 10 is provided with a first slot 101 for engaging with the second hook 153, so that the cam 15 and the pen shell 10 are completely fixed. That is, this embodiment utilizes the engagement of the second hook 153 and the first slot 101 to simultaneously achieve axial and circumferential limiting of the cam 15 and the pen shell 10.

[0139] Furthermore, to facilitate axial limiting of the clutch 6 and the dosage indicator 9, please refer to Figure 44. In some embodiments, the limiting portion 102 of the pen housing 10 is an inner annular tooth provided on the inner sidewall of the pen housing 10 and distributed circumferentially. The distal end of the inner annular tooth is used to stop and limit the dosage indicator 9. The inner annular tooth also engages with the second external spline 62 provided on the outer periphery of the clutch 6 to limit the circumferential movement of the clutch 6 when it moves to the distal position, and disengages from the inner annular tooth when it moves to the proximal position. That is, the limiting portion 102 in this embodiment serves to both axially limit the proximal position of the dosage indicator 9 and axially limit the distal position of the clutch 6. In other words, during injection, the injection is completed when the proximal end of the dosage indicator 9 abuts against the distal end of the inner annular tooth. In addition, when the clutch 6 is in the far end position, the inner edge annular teeth and the second outer spline 62 cooperate to achieve circumferential restriction between the clutch 6 and the pen shell 10, so that the clutch 6 cannot rotate under the restriction of the pen shell 10. When the inner edge annular teeth and the second outer spline 62 disengage, the circumferential restriction between the clutch 6 and the pen shell 10 is released, so that the clutch 6 can rotate relative to the pen shell 10.

[0140] Additionally, to facilitate the installation of the cartridge bottle 2, please refer to Figures 45 to 47. In some embodiments, a pen refill holder 14 is connected to the proximal end of the pen shell 10. The pen refill holder 14 is used for inserting the cartridge bottle 2 from its distal end. The proximal end of the pen refill holder 14 is used to connect the needle 1. The distal end of the pen refill holder 14 is provided with a raised rib 143 and a second slot 144. The pen shell 10 is provided with a third limiting notch 108 for engaging with the raised rib 143. The cam 15 is provided with a first hook 152 for engaging with the second slot 144 (as shown in Figure 37). During assembly, the cartridge 2 is first inserted into the pen refill holder 14 from the far end. Then, the protruding rib 143 of the pen refill holder 14 is aligned with the third limiting notch 108, causing the pen refill holder 14 and the pen body to move relative to each other axially to achieve assembly. That is, the protruding rib 143 is inserted into the third limiting notch 108. During this process, the first hook 152 engages in the second slot 144, fixing the pen refill holder 14 to the cam 15, thereby fixing the pen refill holder 14 to the pen body. In addition, the protruding rib 143 protrudes from the third limiting notch 108 to prevent the adjustable-dose auto-injection pen from rolling. That is, when the adjustable-dose auto-injection pen is placed on an inclined table, the protruding rib 143 prevents the adjustable-dose auto-injection pen from rolling onto the ground.

[0141] Please continue referring to Figure 46. In some embodiments, the proximal end of the refill holder 14 is provided with a threaded structure 141 for threaded connection with the needle 1. In some embodiments, the needle 1 is a disposable needle 1. In addition, in some embodiments, the side wall of the refill holder 14 is provided with an elongated through hole 145 extending along its length direction. The elongated through hole 145 is used to observe the position of the cartridge stopper 3 of the cartridge 2 so that the user can know the remaining amount of medicine in the cartridge 2.

[0142] Additionally, referring to Figures 48 and 49, in some embodiments, the pen housing 10 further includes a pen cap 13 detachably fitted around the outer periphery of the refill holder 14, so as to cover the needle 1 and the refill holder 14 when the adjustable-dose auto-injection pen is not in use. Further, in some embodiments, one of the pen cap 13 and the refill holder 14 is provided with a protrusion 142, and the other is provided with a groove 131 for engaging with the protrusion 142. In some embodiments, the groove 131 is an annular groove 131, and the protrusion 142 and the annular groove 131 are loosely fitted. Further, in some embodiments, the annular groove 131 is provided with a one-sided positioning portion 132 for limiting the circumferential rotation angle of the protrusion 142 relative to the annular groove 131.

[0143] Additionally, referring to Figures 50 and 51, in some embodiments, the adjustable-dose auto-injection pen includes a screw thread 4 connected to the front end of the plunger 18. The screw thread 4 is located at the distal end of the cartridge stopper 3 of the cartridge 2 and is used to expel liquid contained in the cartridge 2 through the needle 1 under the action of the plunger 18. Further, in some embodiments, the distal end of the screw thread 4 has two opposing bosses, each with a locking portion on its opposite side. The plunger 18 has a neck groove 183, which engages with the locking portions to limit the axial position of the screw thread 4 at the end of the plunger 18. Further, in some embodiments, the distal center of the screw thread 4 also has a recess 41, which allows the conical top 184 of the proximal end of the plunger 18 to extend into, providing support to the conical top 184 and reducing friction. Additionally, in some embodiments, the proximal end of the screw thread 4 is a propelling plane 43 for contacting the cartridge stopper 3.

[0144] It should be noted that the above embodiments do not limit the preset preload of the dynamic elastic element 8, and those skilled in the art can set it according to actual needs. In addition, the above embodiments do not limit the specific installation method of the dynamic elastic element 8. Please refer to Figures 52 to 55. In some embodiments, the dynamic elastic element 8 has a first bending portion 81 at its distal end and a second bending portion 82 at its proximal end. The pen shell 10 has a shell cover 20 at its distal end. The shell cover 20 has a third slot 201 for engaging with the first bending portion 81, and the sleeve 17 has a fourth slot 174 for engaging with the second bending portion 82. In other words, in this embodiment, the connection between the dynamic elastic element 8 and the shell cover 20 is achieved by the first bending portion 81 engaging with the third slot 201, that is, the connection between the dynamic elastic element 8 and the pen shell 10 is achieved. The connection between the dynamic elastic element 8 and the sleeve 17 is achieved by the second bending portion 82 engaging with the fourth slot 174. The dynamic elastic element 8, with a preset preload, is installed between the shell cover 20 and the sleeve 17. After assembly, the sleeve 17 is constantly subjected to a force applied by the dynamic elastic element 8 to rotate in the second direction, so that the sleeve 17 always has a tendency to rotate in the second direction. In some embodiments, the dynamic elastic element 8 is a torsion spring.

[0145] Furthermore, this embodiment does not limit the specific arrangement of the cover 20 on the pen shell 10, as long as the cover 20 can be placed on the pen shell 10. Referring to Figures 54 and 43, in some embodiments, the outer periphery of the cover 20 is provided with a third hook 203, and the pen shell 10 is provided with a fifth slot 107 for engaging with the third hook 203, thereby limiting the axial position of the cover 20 and the pen shell 10; the outer periphery of the cover 20 is provided with a radial flange 202, and the pen shell 10 is provided with a second limiting notch 106 for engaging with the radial flange 202, thereby limiting the circumferential position of the cover 20 and the pen shell 10. It should be noted that this embodiment does not limit the specific number of the third hook 203, the fifth slot 107, the radial flange 202, and the second limiting notch 106, which can be set by those skilled in the art according to actual needs. For example, there are two third hooks 203 and two radial flanges 202. The two third hooks 203 are symmetrically arranged, the two radial flanges 202 are symmetrically arranged, and the line connecting the two third hooks 203 is perpendicular to the line connecting the two radial flanges 202.

[0146] It should also be noted that, in this specification, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0147] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other. In the absence of contradictions, the above embodiments can be combined arbitrarily.

[0148] The adjustable-dose automatic injection pen provided by this invention has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the embodiments above are merely for the purpose of helping to understand the method and core ideas of this invention. It should be noted that those skilled in the art can make various improvements and modifications to this invention without departing from its principles, and these improvements and modifications also fall within the protection scope of this invention.

Claims

1. An adjustable-dose automatic injection pen, characterized in that, include: The pen housing assembly includes a pen housing (10) and a rotatable knob (11) and a pressable button (21) respectively disposed on the pen housing (10); A dose adjustment component, linked to the knob (11), is used to increase the set dose when the knob (11) is rotated in a first direction, and to decrease the set dose when the knob (11) is rotated in a second direction opposite to the first direction; An injection component, linked to the button (21), is used to perform injection when the button (21) is pressed; The clutch (6) is connected between the dosage adjustment component and the injection component, and has a first position state and a second position state. When the button (21) is not pressed, the clutch (6) is in the first position state, and the clutch (6) cooperates with the pen shell (10) to limit the position, so that the injection component remains unchanged. When the button (21) is pressed, the clutch (6) is in the second position state, and the clutch (6) is disengaged from the pen shell (10), so that the clutch (6) is driven by the driving force to drive the injection component to perform injection.

2. The adjustable-dose automatic injection pen according to claim 1, characterized in that, The dose adjustment component includes: The drive rod (19) is axially connected to the button (21) and the clutch (6) respectively. When the button (21) is not pressed, the drive rod (19) is engaged with the knob (11) and the clutch (6) is in the first position state. When the button (21) is pressed, the drive rod (19) is disengaged from the knob (11) and the clutch (6) is in the second position state. The sleeve (17) is axially limited with the drive rod (19) and has a spring plate (171). The clutch (6) is provided with a first inner one-way tooth (63). The spring plate (171) extends into the first tooth groove of the first inner one-way tooth (63) so that the clutch (6) limits the rotation of the sleeve (17) in the second direction. The gripper (7) is fixedly connected to the drive rod (19). When the clutch is in the first position, the drive rod (19) rotates in the first direction, and the gripper (7) drives the sleeve (17) to rotate synchronously. When the drive rod (19) rotates in the second direction, the gripper (7) squeezes the spring piece (171), causing the spring piece (171) to disengage from the first tooth groove, and after the spring piece (171) disengages from the first tooth groove, it drives the sleeve (17) to rotate synchronously in the second direction. The dosage indicator (9) can rotate synchronously with the sleeve (17) and can move axially relative to the sleeve (17), and is threadedly connected to the pen shell (10).

3. The adjustable-dose automatic injection pen according to claim 2, characterized in that, The pen casing (10) is provided with a limiting part (102) for abutting against the dose indicator (9) to stop the dose indicator (9) from moving toward the injection end of the injection pen.

4. The adjustable-dose automatic injection pen according to claim 2, characterized in that, The injection assembly includes: A push rod (18) is rotatably and synchronously axially disposed in the housing (10); The radial wheel (5) is circumferentially limited by the push rod (18), and the push rod (18) can move axially relative to the radial wheel (5). The radial wheel (5) can rotate unidirectionally relative to the housing (10) in the second direction. The clutch (6) is always circumferentially limited by the radial wheel (5). A dynamic elastic element (8), having a preset torsional preload, is installed between the sleeve (17) and the pen shell (10) so that the sleeve (17) always tends to rotate in the second direction relative to the pen shell (10).

5. The adjustable-dose automatic injection pen according to claim 4, characterized in that, Also includes: The limiter (16) is threadedly connected to the push rod (18) and circumferentially limited by the drive rod (19) so that the two can rotate synchronously and can move axially along the drive rod (19). When the drive rod (19) rotates in the first direction, the limiter (16) rotates and moves away from the injection direction along the push rod (18) so that the axial position of the limiter (16) relative to the push rod (18) corresponds to the set dose of each injection of the dose indicator (9). When the limiter (16) rotates and moves to the end of the thread at the far end of the push rod (18), the dose indicator (9) reaches the total dose setting position of the final dose injection.

6. The adjustable-dose automatic injection pen according to claim 3, characterized in that, The dose indicator (9) is provided with a limiting groove (92), and the sleeve (17) is provided with a protruding spring (172). The protruding spring (172) is used to spring into the limiting groove (92) after the dose indicator (9) abuts against the limiting part (102) to generate a collision and make a sound to indicate that the injection is complete.

7. The adjustable-dose automatic injection pen according to any one of claims 2-6, characterized in that, The drive rod (19) has at least two end grippers (191) distributed along the same circumference at one end near the injection direction. The outer periphery of the end grippers (191) has a first protrusion (192) and a second protrusion (193) spaced apart along the axial direction. The outer periphery of the drive rod (19) also has a third protrusion (194) spaced apart from the second protrusion (193) along the axial direction. The clutch (6) is provided with a radially inwardly protruding inner flange (64), and the inner flange (64) and the spring plate (171) are respectively provided in the gap between the first protrusion (192) and the second protrusion (193) so that the clutch (6), the sleeve (17) and the drive rod (19) are axially limited and connected. The gripper (7) is engaged in the gap between the second protrusion (193) and the third protrusion (194), and one of the gripper (7) and the drive rod (19) is provided with a first limiting notch (72), and the other is provided with a first limiting rib (195) that cooperates with the first limiting notch (72) for limiting.

8. The adjustable-dose automatic injection pen according to any one of claims 2-6, characterized in that, The claw device (7) is provided with a claw sidewall (71) located outside the spring piece (171). The thickness of the claw sidewall (71) gradually increases from one side to the other in the circumferential direction, so that when the claw device (7) rotates with the drive rod (19) in the second direction, the claw sidewall (71) squeezes the spring piece (171) and causes the spring piece (171) to disengage from the first tooth groove.

9. The adjustable-dose automatic injection pen according to any one of claims 2-6, characterized in that, The gripper (7) and the drive rod (19) are either integrally formed or separate structures.

10. The adjustable-dose automatic injection pen according to any one of claims 2-6, characterized in that, One of the outer periphery of the end of the drive rod (19) away from the injection direction and the knob (11) is provided with a protruding tooth (196) and the other is provided with a tooth groove (111). When the button (21) is not pressed, the protruding tooth (196) engages with the tooth groove (111). When the button (21) is pressed, the protruding tooth (196) disengages from the tooth groove (111). The drive rod (19) has a fourth protrusion (197) on the inner side of the end away from the injection direction. The button (21) has an end protrusion (211). The end protrusion (211) is used to insert into the interior of the drive rod (19) so that the side of the end protrusion (211) away from the injection direction abuts and limits the fourth protrusion (197) facing the injection direction. A return spring (12) is provided between the button (21) and the knob (11) to provide an elastic force to the button (21) to move away from the injection direction so that the button (21) is reset.

11. The adjustable-dose automatic injection pen according to claim 4, characterized in that, The injection assembly also includes a cam (15) connected to the pen shell (10); The outer periphery of the push rod (18) is provided with two rows of discontinuous helical teeth (181) distributed along the axial direction to form a discontinuous first external thread. The cam (15) is provided with a third internal thread (154) for threaded connection with the first external thread, so that when the push rod (18) is limited by the cam (15), it moves axially in the injection direction when it rotates in the second direction. A first limiting guide groove (182) extending axially is provided between the two rows of helical teeth (181), and the radial wheel (5) is provided with a radial inner protrusion (51) for slidingly engaging with the first limiting guide groove (182); The radial wheel (5) is also provided with a spring arm (53), and the cam (15) is provided with a second inner one-way tooth (151). The spring arm (53) cooperates with the second inner one-way tooth (151) so that the radial wheel (5) can rotate relative to the cam (15) in a second direction, and the radial wheel (5) emits a continuous intermittent sound when rotating relative to the cam (15) to indicate the injection.

12. The adjustable-dose automatic injection pen according to claim 11, characterized in that, One of the radial wheel (5) and the clutch (6) is provided with a first internal spline (61), and the other is provided with a first external spline (52) for sliding engagement with the first internal spline (61), so that the clutch (6) can move axially relative to the radial wheel (5) and that the radial wheel (5) and the clutch (6) are always circumferentially limited.

13. The adjustable-dose automatic injection pen according to claim 3, characterized in that, The limiting part (102) is an inner annular tooth provided on the inner sidewall of the pen shell (10) and distributed circumferentially. The distal end of the inner annular tooth is used to stop and limit the dose indicator (9). The inner annular tooth is also used to cooperate with the second external spline (62) provided on the outer periphery of the clutch (6) to limit the circumferential movement of the clutch (6) when the clutch (6) moves to the distal position. When the clutch (6) moves to the proximal position, the second external spline (62) disengages from the inner annular tooth.

14. The adjustable-dose automatic injection pen according to any one of claims 1-6, characterized in that, The pen shell (10) is connected to a pen cartridge holder (14) at one end near the injection direction. The pen cartridge holder (14) is used to hold the cartridge (2). The pen cartridge holder (14) at one end near the injection direction is used to connect the needle (1). The pen cartridge holder (14) at one end away from the injection direction is provided with a raised rib (143) and a second slot (144). The pen shell (10) is provided with a third limiting notch (108) for engaging with the raised rib (143). The cam (15) is provided with a first hook (152) for engaging with the second slot (144). The raised rib (143) protrudes from the third limiting notch (108) so that the raised rib (143) is used to prevent the adjustable dose auto-injection pen from rolling.

15. The adjustable-dose automatic injection pen according to claim 14, characterized in that, The pen casing (10) also includes: The screw fastener (4) has two opposing boss hooks (42) at the end away from the injection direction. The push rod (18) has a neck groove (183) for engaging with the boss hooks (42) to axially limit the screw fastener (4) and the push rod (18). The end of the screw fastener (4) away from the injection direction also has a recess (41) for the conical top (184) of the push rod (18) near the injection direction to extend into. The end of the screw fastener (4) near the injection direction is a push-in plane (43) for contacting the cartridge stopper (3) of the cartridge bottle (2).

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