Dose adjustment mechanism of injector pen and injector pen

Abstract

A dose adjustment mechanism, comprising a power rod and a sleeve into which the power rod is inserted. The sleeve comprises an inner cylinder and a snap portion. The snap portion has a base portion and a head portion. The base portion is fixedly connected to the inner cylinder, and the head portion is closer to the center of the inner cylinder than the base portion. The snap portion is provided with at least two snap-fitting surfaces. The power rod has a snap hook, and the snap hook is snap-fitted to the outer side of the snap portion. The snap hook abuts against the snap-fitting surfaces when the snap hook and the snap portion are in a snap-fitting position. The snap-fitting surfaces are obliquely arranged relative to the axial direction of the inner cylinder. The ends of the snap-fitting surfaces located at the base portion are close to each other, and the ends located at the head portion are away from each other. The resistance of an injector pen to impact is improved, and the durability of a product is improved.

Description

A dosage adjustment mechanism for an injection pen and the injection pen itself.

[0001] This application claims priority to Chinese Patent Application No. 202410906127.3, filed on July 8, 2024, entitled "A Dosage Adjustment Mechanism for an Injection Pen and an Injection Pen", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This invention relates to the field of drug delivery device technology, and more specifically, to a dosage adjustment mechanism for an injection pen and the injection pen itself. Background Technology

[0003] An injection pen is a drug delivery method that combines medication and device into one device; its full name is pen-type injection device. Compared with traditional devices such as glass syringes and infusion pumps, injection pens can safely and conveniently deliver a measured dose, greatly improving patient compliance. Therefore, they are very suitable for patients with diabetes and other conditions that require long-term medication. The injection pen includes a dose adjustment mechanism, which consists of a power rod and a sleeve that are inserted into each other. Existing injection pens have poor impact resistance. In the event of an impact such as a drop, especially a vertical drop, the sleeve and the power rod are prone to loosening. Summary of the Invention

[0004] The purpose of this application is to provide a heat exchanger with enhanced heat exchange performance.

[0005] This application provides a dosage adjustment mechanism for an injection pen and an injection pen, including a power rod and a sleeve inserted into the power rod. The sleeve includes an inner cylinder and a clamp portion. The clamp portion has a root and a head. The root is fixedly connected to the inner cylinder, and the head is closer to the center of the inner cylinder than the root. The clamp portion has at least two engaging surfaces. The power rod has a hook that engages with the outer side of the clamp portion. When the hook and the clamp portion are in the engaged position, the hook abuts against the engaging surfaces. The engaging surfaces are inclined relative to the axial direction of the inner cylinder, with the ends of each engaging surface located at the root being close together and the ends located at the head being far apart.

[0006] When the dose adjustment mechanism is subjected to axial impact force, the hook set on the power rod will slide radially relative to the locking surface. However, due to the inclined setting of the locking surface, it will form a radial stop on the hook, preventing the hook from radially disengaging from the locking part, thus increasing the impact resistance of the dose adjustment mechanism.

[0007] Optionally, the latch includes a main body and at least two latch arms extending radially from the main body, wherein one end of the latch arm that connects to the main body serves as the root of the latch, and the other end of the latch arm that is spaced apart from the main body serves as the head of the latch.

[0008] The locking arms are evenly distributed along the circumference of the main body, and the surface of each locking arm facing the main body serves as the locking surface.

[0009] Optionally, the clip portion further includes a mounting bridge, the clip portion being fixedly connected to the inner wall of the inner cylinder via the mounting bridge; one end of the main body portion is connected to one end face of the mounting bridge, the main body portion is coaxially arranged with the inner cylinder, and the axis of the inner cylinder passes through the center of the mounting bridge.

[0010] Optionally, the mounting bridge extends radially, and its front end and rear end are fixedly connected to the inner wall of the inner cylinder in its extending direction. The mounting bridge has two side bridge walls, at least a portion of which is spaced apart from the inner wall of the inner cylinder.

[0011] The sleeve has an installation channel, which is defined by the side wall of the mounting bridge, the locking arm, and the inner side wall of the inner cylinder, and the installation channel allows the locking hook to pass through;

[0012] The hook is configured to retract radially when inserted into the mounting channel. When the hook and the arm are in the engaged position, a portion of the hook is located within the mounting channel, and the maximum radial dimension of the portion of the hook located within the mounting channel is greater than the radial dimension of the mounting channel.

[0013] Optionally, the inner cylinder has a flared opening, with the opening located at the larger diameter end of the flared section.

[0014] Optionally, the side wall of the inner cylinder also has a constant diameter section, which is connected to the flared section;

[0015] The position where the equal diameter section meets the flared section is located within the installation channel.

[0016] Optionally, the two side walls of the mounting bridge retract from both ends of the mounting bridge toward the center of the mounting bridge.

[0017] Optionally, the sleeve further includes an insert rod portion that is inserted into the power rod, the tail end of the insert rod portion being fixedly connected to the mounting bridge and located on the side of the mounting bridge away from the main body portion; the main body portion has a wedge-shaped structure, and the two clamping arms are connected to the large-diameter end of the main body portion.

[0018] Optionally, the portion of the power rod located outside the inner cylinder is further fitted with a planetary cylinder, which is rotatable relative to the power rod to move axially relative to the power rod. Attached Figure Description

[0019] Figure 1 is an exploded view of the dose adjustment mechanism in an embodiment of the present invention;

[0020] Figure 2 is a side view of the sleeve;

[0021] Figure 3 is a top view of Figure 2;

[0022] Figure 4 is a bottom view of Figure 2;

[0023] Figure 5 is a schematic diagram of the dose adjustment mechanism in the state where it is not subjected to axial impact force;

[0024] Figure 6 is a schematic diagram of the dose adjustment mechanism subjected to axial impact force.

[0025] Explanation of reference numerals in the attached drawings: 100, Dosage adjustment mechanism; 1, Power rod; 11, Hook; 11a, Hook head; 11b, Hook back; 2, Sleeve; 21, Inner cylinder; 21a, Flared section; 21b, Equal diameter section; 22, Outer cylinder; 23, Insert rod part; 3, Clamp part; 3a, Root part; 3b, Head; 31, Main body part; 32, Clamp arm; 32a, Clamping surface; 32b, Clamp back; 33, Mounting bridge; 33a, Side bridge wall; 33b, Top surface; 33c, Bottom surface; 4, Mounting channel; 5, Planetary cylinder. Detailed Implementation

[0026] This invention provides a dosage adjustment mechanism for an injection pen and the injection pen itself. By improving the structure of the dosage adjustment mechanism, the impact resistance of the injection pen is increased, and the durability of the product is improved.

[0027] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] Figure 1 is an exploded view of the dose adjustment mechanism in an embodiment of the present invention; Figure 2 is a side view of the sleeve; Figure 3 is a top view of Figure 2; Figure 4 is a bottom view of Figure 2; Figure 5 is a schematic diagram of the dose adjustment mechanism in a state where it is not subjected to axial impact force; Figure 6 is a schematic diagram of the dose adjustment mechanism in a state where it is subjected to axial impact force.

[0029] Traditional injection pens typically include a pen barrel assembly and a pen cap assembly connected together. The pen cap assembly is used to connect to a drug-containing container (such as a cartridge). The pen barrel assembly specifically includes a pen barrel body, a button mechanism, a dose adjustment mechanism 100, and a transmission mechanism. The dose adjustment mechanism 100 stores kinetic energy by operating it, and the kinetic energy stored in the dose adjustment mechanism 100 is released by pressing the button mechanism. The dose adjustment mechanism 100 pushes the stopper of the cartridge via the transmission mechanism to eject the drug from the cartridge, thereby realizing drug injection.

[0030] The dosage adjustment mechanism 100 has a rotating end and an adapter end; specifically, the dosage adjustment mechanism 100 includes a power rod 1 and a planetary cylinder 5. The planetary cylinder 5 is sleeved on the power rod 1, and a spiral channel is defined between the two. The spiral channel extends spirally along the axial direction and is provided with balls. The planetary cylinder 5 can rotate relative to the power rod 1 and maintain its axial relative position through the friction between the balls and the spiral channel. The planetary cylinder 5 and the pen holder body can form a circumferential limiting fit, that is, the planetary cylinder 5 and the pen holder body can rotate synchronously, and the two together form the adapter end.

[0031] The dosage adjustment mechanism 100 also includes a sleeve 2 that is inserted into the power rod 1. The axial direction of the sleeve 2 is defined as the length direction of the flow adjustment mechanism 100. The sleeve 2 and the power rod 1 are circumferentially stopped, meaning that the power rod 1 and the sleeve 2 can rotate synchronously, forming a rotating end. The adapter end and the rotating end are elastically connected by a torsion spring. The sleeve 2 is selectively connected to the transmission mechanism. An external force can drive the rotating end (power rod 1) to rotate in the direction of the set injection dose. At this time, the adapter end remains stationary, the end of the torsion spring connected to the adapter end is stationary, and the end connected to the rotating end rotates and stores energy. A ball bearing is used to fix the adapter end at the set injection dose. Position; at this time, the rotating end engages with the transmission mechanism to form a transmission connection; by operating to release the stored energy of the torsion spring, under the elastic drive of the torsion spring, the rotating end rotates in the opposite direction to the adapter end, and then pushes the aforementioned bottle stopper down through the transmission mechanism to realize drug injection; thus, the user can adjust the stored energy of the torsion spring by controlling the degree of rotation of the rotating end relative to the adapter end, and the stored energy of the torsion spring is related to the amount of drug pushed by the transmission mechanism to the bottle stopper, thereby adjusting the dosage of drug injection; however, the existing injection pen has poor impact resistance, and under impact such as falling, especially when falling vertically, the sleeve 2 and the power rod 1 are prone to loosening.

[0032] In this invention, the dosage adjustment mechanism 100 of the injection pen is improved to enhance its impact resistance. Specifically, the sleeve 2 includes an outer cylinder 22, an inner cylinder 21, a clamping part 3, and an inserting rod part 23. The tail end of the inner cylinder 21 is built into the outer cylinder 22, and the head end extends out of the outer cylinder 22. The clamping part 3 is disposed inside the inner cylinder 21 and fixedly connected to the inner cylinder 21. The power rod 1 has a hook 11, which engages with the outside of the clamping part 3. The hook 11 and the clamping part 3 are connected... The snap-fit ​​position is closer to the beginning of the inner cylinder 21; axially, the midpoint between the beginning and end of the inner cylinder 21 is defined as the center of the inner cylinder 21, with the side pointing towards the center of the inner cylinder 21 being the inside, and the opposite being the outside; radially, the side closer to the axis of the inner cylinder 21 is the inside, and correspondingly, the side farther from the axis of the inner cylinder 21 is the outside; the snap-fit ​​part 3 has a root 3a and a head 3b distributed axially back and forth, the root 3a being fixedly connected to the inner cylinder 21, and the head 3b being more prominent than the root 3a. Closer to the center of the inner cylinder 21; the latch 3 has at least two latching surfaces 32a, which are inclined relative to the axial direction of the inner cylinder 21. The ends of each latching surface 32a located at the root 3a are close to each other, and the ends located at the head 3b are far apart. As shown in the figure, the radial distance between the two latching surfaces 32a gradually decreases from the head 3b toward the root 3a. The power rod 1 has a hook 11, which is latched to the outside of the latch 3. When the hook 11 and the latch 3 are in the engaged position, the hook 11 abuts against the latching surface 32a. In this way, when the dose adjustment mechanism 100 is subjected to an axial impact force, the hook 11 provided on the power rod 1 will slide radially relative to the latching surface 32a. However, since the latching surface 32a is inclined, it will form a radial stop on the hook 11, preventing the hook 11 from radially disengaging from the latch 3, thus increasing the impact resistance of the dose adjustment mechanism 100.

[0033] In a more specific embodiment, the latch portion 3 includes a main body portion 31 and at least two latching arms 32 extending radially from the main body portion 31. The end of each latching arm 32 that connects to the main body portion 31 serves as the root portion 3a of the latch portion 3, and the end of each latching arm 32 that is spaced apart from the main body portion 31 serves as the head portion 3b of the latch portion 3. The main body portion 31 extends axially by a certain dimension and is coaxially arranged with respect to the inner cylinder 21. Two latching arms 32 extend radially from the side wall of the main body portion 31, and the two latching arms 32 are radially symmetrically arranged relative to the main body portion 31. The two locking arms 32 are connected to the large-diameter end of the main body 31 in a wedge-shaped structure, thereby increasing the support strength of the main body 31 for the locking arms 32. Each locking arm 32 has a locking surface 32a, which is located on the side of the locking arm 32 closer to the main body 31. That is, the surface of each locking arm 32 facing the main body 31 is the locking surface 32a. Here, the number of locking arms 32 can be odd or even, and the locking arms 32 can be arranged symmetrically in the radial direction or evenly distributed in the circumferential direction, so as to form a locking engagement with the hook 11.

[0034] In one specific implementation, to fix the clamp part 3 to the inner cylinder 21, the clamp part 3 further includes a mounting bridge 33. The mounting bridge 33 has a top surface 33b and a bottom surface 33c. The top surface 33b of the mounting bridge 33 is connected to a plug rod part 23, which is inserted into the power rod 1. The power rod 1 and the plug rod part 23 form a circumferential anti-rotation. The bottom surface 33c of the mounting bridge 33 is fixedly connected to the root part 3a of the main body part 31. The plug rod part 23 and the main body part 31 are coaxially arranged. The mounting bridge 33 is placed horizontally inside the inner cylinder 21 and extends radially. Its two ends in the extension direction are respectively connected to the inner cylinder 21. The inner wall of the cylinder 21 is fixedly connected; the mounting bridge 33 has two side bridge walls 33a. In the radial direction, at least a portion of the two side bridge walls 33a is spaced apart from the inner wall of the inner cylinder 21. In a specific example, the middle portion of the two side bridge walls 33a forms a non-contact area before being spaced apart from the inner wall of the inner cylinder 21. The radial ends of the two side bridge walls 33a abut against and connect with the inner wall of the inner cylinder 21. In the axial direction, each side bridge wall 33a is respectively connected to the back 32b of the corresponding side of the locking arm 32. That is, the root 3a of the back 32b is connected to one axial end of the side bridge wall 33a. 32b refers to the side wall of the locking arm 32 that is away from the main body 31. That is, compared with the locking surface 32a, the locking back 32b is closer to the inner wall of the inner cylinder 21 and farther away from the main body 31. The sleeve 2 has an installation channel 4 that extends axially to connect the upper and lower sides of the mounting bridge 33. The installation channel 4 is defined by the side bridge wall 33a of the mounting bridge 33, the locking back 32b, and part of the inner wall of the inner cylinder 21. The installation channel 4 allows the locking hook 11 to pass through. That is, the number of installation channels 4 is matched with the number of locking arms 32 and corresponds one-to-one. When there are two locking arms 32, There are also two mounting channels 4; the mounting channels 4 allow the hooks 11 to pass through to form a snap-fit; specifically, the radial dimensions of the two hooks 11 can change because the hooks 11 are hook-shaped structures, thus the hooks 11 have elasticity in the radial direction; specifically, the hooks 11 have a hook head 11a and a hook back 11b, the hook head 11a and the hook back 11b are set at an angle, so that the hook head 11a and the hook back 11b have elasticity in the radial direction, and can expand, retract or reset in the radial direction; after the hooks 11 and the locking arm 32 form a snap-fit, the hooks 11 restore their elastic deformation to their initial state.With the hook 11 and the arm 32 in the engaged position, a portion of the hook 11 is located within the mounting channel 4. The maximum radial dimension of the portion of the hook 11 located within the mounting channel 4 is greater than the radial dimension h1 of the mounting channel 4. The maximum radial dimension of the hook 11 is the vertical distance between the hook head 11a and the hook back 11b. The radial dimension h1 of the mounting channel 4 refers to the distance between the back 32b of the arm 32 and the inner wall of the inner cylinder 21. This arrangement increases the interference between the mounting channel 4 and the hook 11. The interference refers to the resistance (friction or pressure) that the mounting channel 4 creates to prevent the hook 11 from entering when it is inserted into the mounting channel 4. By increasing the interference, the hook 11 can also be prevented from radially disengaging from the arm 32 to a certain extent.

[0035] When the dosage adjustment mechanism 100 is subjected to axial impact, the force on each hook 11 will cause it to tend to move away from each other radially. When the hook 11 moves radially, the inclined engagement surface 32a of the hook arm 32 will form a radial stop on the hook 11. At this time, the hook arm 32 will open outward under the action of the hook 11, that is, it will move towards the inner wall of the inner cylinder 21. At this time, the back 32b of the hook arm 32 is closer to the inner wall of the inner cylinder 21 than its initial position, and the radial dimension of the installation channel 4 will shrink accordingly. This reduces the distance between the hook arm 32 and the inner wall of the inner cylinder 21, that is, the radial dimension of the installation channel 4 shrinks, which can further increase the interference between the installation channel 4 and the hook 11, thereby further preventing the hook 11 from coming out of the installation channel 4.

[0036] In the above embodiment, the inner cylinder 21 has a flared opening structure, and the inner cylinder 21 has a flared section 21a. The flared section 21a forms a flared structure, and the power rod 1 enters the inner cylinder 21 through the flared structure. That is, the opening of the inner cylinder 21 is located at the large diameter end of the flared section 21a. At the same time, the side wall of the inner cylinder 21 also has a constant diameter section 21b, which is connected to the small diameter end of the flared section 21a. The position where the constant diameter section 21b and the flared section 21a meet is located within the installation channel 4. That is, part of the wall surrounding the installation channel 4 is the constant diameter section 21b, and part is the flared section 21a. The radial dimension of the installation channel 4 refers to the distance between the clamp arm 32 and the constant diameter section 21b. In this solution, by setting the flared section 21a, the clamp hook 11 can be guided when it is inserted into the installation channel 4, and the insertion space of the clamp hook 11 when it is inserted into the installation channel 4 is increased, reducing the difficulty of docking the clamp hook 11 with the inner cylinder 21.

[0037] In the above embodiment, in order to increase the connection strength between the clip 3 and the inner wall of the inner cylinder 21, the radial distance between the two side bridge walls 33a of the mounting bridge 33 is reduced from the two ends of the mounting bridge 33 toward the center of the mounting bridge 33; that is, the middle of the two side bridge walls 33a is recessed toward each other, and the radial dimension of the two side bridge walls 33a is the largest at the two ends of the mounting bridge 33 and the smallest at the center of the mounting bridge 33; thus, the two side bridge walls 33a are spaced apart from the inner wall of the inner cylinder 21 to form a partial mounting channel 4, thereby increasing the contact area between the two ends of the mounting bridge 33 and the inner wall of the inner cylinder 21, thereby increasing the connection strength between the clip 3 and the inner cylinder 21.

[0038] In another aspect of this application, an injection pen is also provided, which includes the dosage adjustment mechanism 100 described above. By improving the structure of the dosage adjustment mechanism 100, the impact resistance of the injection pen is increased, and the durability of the product is improved.

[0039] The specific structure of the dose adjustment mechanism 100 and the injection pen provided by the present invention has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present invention, and the descriptions of the embodiments above are only for the purpose of helping to understand the core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A dosage adjustment mechanism for an injection pen, characterized in that, The device includes a power rod (1) and a sleeve (2) that is inserted into the power rod (1). The sleeve (2) includes an inner cylinder (21) and a clamp (3). The clamp (3) has a root (3a) and a head (3b). The root (3a) is fixedly connected to the inner cylinder (21). Compared with the root (3a), the head (3b) is closer to the center of the inner cylinder (21). The clamp (3) has at least two engaging surfaces (32a). The power rod (1) has a hook (11). The hook (11) engages with the outside of the clamp (3). When the hook (11) and the clamp (3) are in the engaged position, the hook (11) abuts against the engaging surface (32a). The snap-fit ​​surface (32a) is inclined relative to the axial direction of the inner cylinder (21), and the ends of each snap-fit ​​surface (32a) located at the root (3a) are close to each other, while the ends located at the head (3b) are far apart.

2. The dosage adjustment mechanism of the injection pen according to claim 1, characterized in that, The latch (3) includes a main body (31) and at least two latch arms (32) extending radially from the main body (31). The end of the latch arm (32) that is connected to the main body (31) serves as the root (3a) of the latch (3), and the end of the latch arm (32) that is spaced apart from the main body (31) serves as the head (3b) of the latch (3). The locking arms (32) are evenly distributed along the circumference of the main body (31), and the surface of each locking arm (32) facing the main body (31) serves as the locking surface (32a).

3. The dosage adjustment mechanism of the injection pen according to claim 2, characterized in that, The dosage adjustment mechanism also includes a mounting bridge (33), and the clip (3) is fixedly connected to the inner wall of the inner cylinder (21) through the mounting bridge (33); one end of the main body (31) is connected to one end face of the mounting bridge (33), and the main body (31) is coaxially arranged with the inner cylinder (21).

4. The dosage adjustment mechanism of the injection pen according to claim 3, characterized in that, The mounting bridge (33) extends radially, and the front end and rear end of the mounting bridge (33) are fixedly connected to the inner wall of the inner cylinder (21) in its extending direction. The mounting bridge (33) has two side bridge walls (33a), and at least a portion of each side bridge wall (33a) is spaced apart from the inner wall of the inner cylinder (21). The sleeve (2) has an installation channel (4) which is defined by the side bridge wall (33a), the clamping arm (32) and a portion of the inner side wall of the inner cylinder (21), and the installation channel (4) allows the hook (11) to pass through; The maximum radial dimension of the portion of the hook (11) located within the mounting channel (4) is greater than the radial dimension of the mounting channel (4).

5. The dosage adjustment mechanism of the injection pen according to claim 4, characterized in that, The inner cylinder (21) has a flared section (21a), and the opening of the inner cylinder (21) is located at the large diameter end of the flared section (21a).

6. The dosage adjustment mechanism of the injection pen according to claim 5, characterized in that, The inner cylinder (21) also has a constant diameter section (21b) on its side wall, which is connected to the flared section (21a); The position where the equal diameter section (21b) and the flared section (21a) meet is located within the installation channel (4).

7. The dosage adjustment mechanism of the injection pen according to any one of claims 4-6, characterized in that, The two side walls (33a) of the mounting bridge (33) retract from both ends of the mounting bridge (33) toward the center of the mounting bridge (33).

8. The dosage adjustment mechanism of the injection pen according to any one of claims 3-6, characterized in that, The sleeve (2) also includes a plug rod part (23) that is inserted into the power rod (1). The tail end of the plug rod part (23) is fixedly connected to the mounting bridge (33) and is located on the side of the mounting bridge (33) away from the main body part (31). The main body part (31) has a wedge-shaped structure, and both of the clamping arms (32) are connected to the large diameter end of the main body part (31).

9. The dosage adjustment mechanism of the injection pen according to any one of claims 1-6, characterized in that, The portion of the power rod (1) located outside the inner cylinder (21) is also fitted with a planetary cylinder (5), which is rotatable relative to the power rod (1) to move axially relative to the power rod (1).

10. An injection pen, characterized in that, Includes the dosage adjustment mechanism (100) of the injection pen according to any one of claims 1-9.

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