An injection pen

Abstract

The invention discloses an injection pen, comprising a pen barrel and a pusher assembly arranged in the pen barrel, wherein the pusher assembly comprises a screw sleeve arranged in the pen barrel, a screw matched with a screw sleeve lead screw, a stroke shaft sleeved outside the screw, a limit clutch shaft sleeved outside the stroke shaft, a limit sheet matched with a thread of the limit clutch shaft, a dose barrel sleeved outside the limit clutch shaft, and a button arranged at the top of the pen barrel; the screw passes through the screw sleeve and is connected with a rubber plug of a cartridge bottle, and when the cartridge bottle is installed in place, the cartridge bottle can push the screw sleeve to link with the stroke shaft. When the dose barrel sets the dose, the stroke shaft does not rotate, and the screw does not move, and the dose setting can be completed smoothly in this process; when the dose barrel is injected to set the dose, the button is pressed to force the dose barrel to be screwed in, the screw sleeve and the stroke shaft are rotated in linkage, and then the screw matched with the screw sleeve lead screw drives the rubber plug to push the cartridge bottle medicine.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and in particular to an injection pen. Background Art

[0002] Currently, drug injections on the market mainly use disposable sterile syringes, but the injection process requires a visit to a hospital and must be operated and injected by professionals. The ease of operation is not suitable for self-management of most chronic disease patients.

[0003] In summary, how to achieve quantitative injection of an injection pen has become a technical problem that those skilled in the art need to solve urgently. Summary of the invention

[0004] The object of the present invention is to provide an injection pen to achieve quantitative injection of the injection pen.

[0005] In order to achieve the above-mentioned object, the present invention provides an injection pen, comprising a pen barrel and a propelling component arranged in the pen barrel;

[0006] The pusher assembly includes a screw sleeve arranged in the pen barrel, a screw matched with the screw sleeve lead screw, a stroke shaft sleeved outside the screw, a limit clutch shaft sleeved outside the stroke shaft, a limit piece threadedly matched with the limit clutch shaft, a dosage barrel sleeved outside the limit clutch shaft, and a button arranged at the top of the pen barrel;

[0007] The screw passes through the screw sleeve and is connected to the rubber plug of the cartridge bottle, and when the cartridge bottle is installed in place, the cartridge bottle can push the screw sleeve to link with the stroke shaft;

[0008] The stroke shaft can rotate unidirectionally along its own axis, and an outer diameter rib is provided on the outer diameter of the bottom end of the stroke shaft, the outer diameter of the outer diameter rib is larger than the inner diameter of the step hole provided in the pen barrel, and the outer diameter rib is used to limit the displacement of the stroke shaft moving toward the top end of the pen barrel, the stroke shaft is limited in the axial direction of the limit clutch shaft, and the displacement of the stroke shaft relative to the axial sliding of the limit clutch shaft is a preset stroke displacement;

[0009] A limiting groove for limiting the rotation of the limiting piece is arranged in the dosage barrel, and a limiting rib for supporting the bottom end of the limiting piece is arranged at the bottom end of the limiting groove, and a limiting rib for limiting the displacement of the top end of the limiting piece is also arranged on the limiting clutch shaft;

[0010] The inner end surface of the bottom of the dosage barrel is provided with end face teeth which are clutch-connected to the limit clutch shaft, the dosage barrel is threadedly connected to the pen barrel, and the screwing direction of the dosage barrel is the same as the fixed axis unidirectional rotation direction of the stroke shaft;

[0011] The button is used to apply axial pressure to the limit clutch shaft; when and only when the button is subjected to axial pressure, the dose cylinder is in driving connection with the limit clutch shaft.

[0012] Preferably, an outer diameter groove is formed on one of the outer side wall of the stroke shaft and the inner wall of the limit clutch shaft, and a convex key platform is provided on the other, and the convex key platform is in sliding fit with the outer diameter groove.

[0013] Preferably, the propellant assembly further includes a transmission shaft;

[0014] The small shaft end of the transmission shaft is sleeved in the limit clutch shaft, and the one-way ratchet teeth on the small shaft end of the transmission shaft are in one-way driving connection with the one-way ratchet teeth on the limit clutch shaft.

[0015] Preferably, the propellant assembly further includes a gear sleeve;

[0016] The gear sleeve is sleeved outside the large shaft end of the transmission shaft, and the one-way ratchet teeth on the gear sleeve are in one-way driving connection with the one-way ratchet teeth on the large shaft end of the transmission shaft;

[0017] The inner wall of the dose cylinder is in snap connection with the outer wall of the gear sleeve.

[0018] Preferably, the injection pen further includes a window cylinder;

[0019] The window cylinder is fixed at the top of the pen barrel, and the scale value on the dose cylinder can be seen through the window cylinder.

[0020] Preferably, both the dose cylinder and the window cylinder are made of materials with a low coefficient of friction;

[0021] The window cylinder is made of a transparent material;

[0022] Or

[0023] The window cylinder is made of a non-transparent material, and a window is provided on the window cylinder through which the scale value on the dose cylinder can be seen.

[0024] Preferably, the propellant assembly further includes a knob sleeve;

[0025] The knob sleeve is sleeved outside the dose cylinder, a limit convex column is provided at the top inside the knob sleeve, the bottom end of the button extends into the knob sleeve, and a limit convex edge capable of being snap-connected with the limit convex column is provided on the outer wall of the bottom end of the button;

[0026] A guide post is arranged inside the button, and a guide sleeve in guiding fit with the guide post is arranged at the top end of the transmission shaft.

[0027] Preferably, the propellant assembly further includes a ratchet ring and an elastic member;

[0028] The ratchet ring is sleeved in the pen barrel and is connected to the one-way ratchet on the step end surface of the pen barrel in a one-way transmission manner;

[0029] A convex key is arranged on the inner wall of the ratchet ring, and a key slot is arranged on the outer wall of the stroke shaft. When injecting, the convex key is inserted into the key slot;

[0030] The elastic member is sleeved outside the stroke shaft, and the bottom end of the elastic member abuts against the limiting ring at the bottom end of the stroke shaft, and the top end of the elastic member abuts against the bottom end of the ratchet ring.

[0031] Preferably, a protrusion is provided at the bottom end of the dosage barrel, and the helical rise angle of the protrusion is the same as the helical rise angle of the pen barrel;

[0032] When the dosage barrel is rotated into the zero position, the protrusion is engaged with the step surface of the pen barrel.

[0033] Preferably, the screw comprises an unthreaded section and a threaded section whose first end is connected to the first end of the unthreaded section;

[0034] The push piece is installed at the second end of the non-threaded section, and the screw sleeve is installed at the first end of the threaded section.

[0035] Compared with the background technology, the above-mentioned injection pen arranges a limit clutch shaft between the stroke shaft and the dose barrel, and the limit clutch shaft and the stroke shaft are axially slidably matched and circumferentially limited in rotation, and the dose barrel and the limit clutch shaft are clutch-driven connected and matched through the end face teeth. When and only when the button is subjected to axial pressure, the dose barrel and the limit clutch shaft are connected through the end face teeth. Therefore, when the dose barrel sets the dose, that is, when the dose barrel is screwed out, since the stroke shaft can only rotate unidirectionally around its own axis in the direction in which the dose barrel is screwed in, when the dose barrel is screwed out, the stroke shaft has a limited rotation effect on the limit clutch shaft, and when the button is not subjected to axial pressure, the end face on the dose barrel is The teeth are not connected to the limit clutch shaft transmission, and then as the dose barrel is screwed out, the limit plate will be lifted and slide outward relative to the stroke shaft axis, and then the limit plate drives the limit clutch shaft to slide outward relative to the stroke shaft axis. During this process, the stroke shaft does not rotate, so the screw will not move, and the process can smoothly complete the dose setting; when the dose barrel is injected to set the dose, press the button to force the dose barrel to rotate. Since the dose barrel and the limit clutch shaft are connected through the end face gear transmission at this time, the clutch rotating shaft is driven by the limit plate to rotate with the dose barrel. At this time, the cartridge bottle has been installed in place, and the screw sleeve rotates in conjunction with the stroke shaft, and then the screw matched with the screw sleeve lead screw will drive the rubber plug to push the cartridge bottle medicine. In addition, a limit rib for the displacement of the top of the limit plate is set on the limit clutch shaft, so that the injection pen dose barrel cannot be adjusted after the drug injection is completed.

[0036] Since the outer diameter of the outer diameter rib is greater than the inner diameter of the hole on the step provided inside the stroke shaft, the outer diameter rib can limit the displacement of the stroke shaft moving towards the top of the pen barrel, preventing the stroke shaft from slipping off. Also, the stroke shaft is axially limited within the limit clutch shaft along the axial direction of the limit clutch shaft, and the axially sliding displacement of the stroke shaft relative to the limit clutch shaft is a preset stroke displacement. The preset stroke displacement realizes the setting of the measurement unit, and the preset stroke displacement can be changed accordingly according to the requirements of different dosage forms of drugs to set the corresponding dosage unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0038] Figure 1 It is a front view structural schematic diagram of the injection pen provided by the embodiment of the present invention;

[0039] Figure 2 For Figure 1 A-A cross-sectional structural schematic diagram of

[0040] Figure 3 It is a left view structural schematic diagram of the injection pen provided by the embodiment of the present invention;

[0041] Figure 4 For Figure 3 B-B cross-sectional structural schematic diagram of

[0042] Figure 5 It is an exploded schematic diagram of the injection pen provided by the embodiment of the present invention;

[0043] Figure 6 It is a structural schematic diagram of the button provided by the embodiment of the present invention;

[0044] Figure 7 It is a structural schematic diagram of the transmission shaft provided by the embodiment of the present invention;

[0045] Figure 8 It is a cross-sectional structural schematic diagram of the transmission shaft provided by the embodiment of the present invention;

[0046] Figure 9 It is a structural schematic diagram of the knob sleeve provided by the embodiment of the present invention;

[0047] Figure 10 It is a structural schematic diagram of the gear sleeve provided by the embodiment of the present invention;

[0048] Figure 11Schematic structural diagram of the dose cylinder provided by the embodiment of the present invention;

[0049] Figure 12 Schematic cross-sectional structural diagram of the dose cylinder provided by the embodiment of the present invention;

[0050] Figure 13 Schematic structural diagram of the window cylinder provided by the embodiment of the present invention;

[0051] Figure 14 Schematic cross-sectional structural diagram of the window cylinder provided by the embodiment of the present invention;

[0052] Figure 15 Schematic structural diagram of the limit clutch shaft provided by the embodiment of the present invention;

[0053] Figure 16 Schematic structural diagram of the limit piece provided by the embodiment of the present invention;

[0054] Figure 17 Schematic cross-sectional structural diagram of the pen barrel provided by the embodiment of the present invention;

[0055] Figure 18 Schematic structural diagram of the stroke shaft provided by the embodiment of the present invention;

[0056] Figure 19 Schematic structural diagram of the screw provided by the embodiment of the present invention.

[0057] Upper Figures 1 - 19 In

[0058] Pen barrel 1, propellant assembly 2, screw sleeve 201, screw 202, stroke shaft 203, limit clutch shaft 204, limit piece 205, dose cylinder 206, button 207, outer diameter rib 2031, step 101, limit groove 2061, limit rib 2041, end face teeth 2062, transmission shaft 208, gear sleeve 209, window cylinder 3, knob sleeve 210, limit convex column 2101, limit convex edge 2071, guide post 2072, guide sleeve 2081, ratchet ring 211, elastic member 212, protrusion 2063, threadless section 2021, threaded section 2022, cartridge 213, rubber stopper 2131, push piece 2132, injection needle 214, pen core holder 215, pen cap 216. Detailed implementation manners

[0059] In order to enable those skilled in the art to better understand the technical solutions provided by the present invention, the following will be combined with the attached Figures 1 - 19 drawings and specific embodiments to further elaborate on the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts fall within the scope of protection of the present invention.

[0060] As Figures 1 - 5 shown, an injection pen provided by an embodiment of the present invention, wherein the injection pen includes a pen barrel 1 and a propellant assembly 2.

[0061] The propellant assembly 2 is disposed within the pen barrel 1, and the structure of the pen barrel 1 is as Figure 17 shown. Specifically, the propellant assembly 2 includes a screw sleeve 201, a screw 202, a stroke shaft 203, a limit clutch shaft 204, a limit piece 205, a dose cylinder 206, and a button 207. The structures of the screw 202, the stroke shaft 203, the limit clutch shaft 204, the limit piece 205, the dose cylinder 206, and the button 207 are as Figure 19 , Figure 18 , Figure 15 , Figure 16 , Figure 11 , Figure 12 and Figure 6 shown.

[0062] Along the direction from the inside to the outside of the pen barrel 1, the screw 202, the stroke shaft 203, the limit clutch shaft 204, and the dose cylinder 206 are sleeved in sequence, that is, the stroke shaft 203 is sleeved outside the screw 202, the limit clutch shaft 204 is sleeved outside the stroke shaft 203, and the dose cylinder 206 is sleeved outside the limit clutch shaft 204.

[0063] The screw sleeve 201 is disposed within the pen barrel 1, the screw sleeve 201 can axially slide within the pen barrel 1, and the screw 202 is in screw-thread fit with the screw sleeve 201. The screw 202 passes through the screw sleeve 201 and is connected to the rubber stopper 2131 of the cartridge 213, and when the cartridge 213 is installed in place, the cartridge 213 can push the screw sleeve 201 to be linked with the stroke shaft 203.

[0064] The limit piece 205 is in screw-thread fit with the limit clutch shaft 204, the stroke shaft 203 can rotate unidirectionally about its own axis, and an outer diameter rib 2031 is provided on the outer diameter of the bottom end of the stroke shaft 203, as Figure 18 shown. The outer diameter of the outer diameter rib 2031 is greater than the inner diameter of the hole on the step 101 provided within the pen barrel 1, and the step 101 of the pen barrel 1 is as Figure 17As shown. The outer diameter rib 2031 is used to limit the displacement of the stroke shaft 203 moving towards the top end of the pen barrel 1. The stroke shaft 203 is axially limited within the limit clutch shaft 204 along the axial direction of the limit clutch shaft 204, and the displacement of the stroke shaft 203 sliding axially relative to the limit clutch shaft 204 is a preset stroke displacement. Therefore, the outer diameter rib 2031 can limit the displacement of the stroke shaft 203 moving towards the top end of the pen barrel 1, preventing the stroke shaft 203 from slipping off. Also, the stroke shaft 203 is axially limited within the limit clutch shaft 204 along the axial direction of the limit clutch shaft 204, and the displacement of the stroke shaft 203 sliding axially relative to the limit clutch shaft 204 is a preset stroke displacement. The preset stroke displacement realizes the setting of the measurement unit, and the preset stroke displacement can be changed accordingly according to the requirements of different dosage forms of drugs, and the corresponding dosage unit can be set.

[0065] A limit groove 2061 for limiting the rotation of the limit piece 205 is provided inside the dosage cylinder 206, and a limit rib 2041 for supporting the bottom end of the limit piece 205 is provided at the bottom end of the limit groove 2061. A limit rib 2041 for limiting the displacement of the top end of the limit piece 205 is also provided on the limit clutch shaft 204.

[0066] An end face tooth 2062 that can be detachably and drivably connected to the limit clutch shaft 204 is provided on the inner end face of the bottom of the dosage cylinder 206, which is used for the separation and meshing drive during dosage setting and injection. The dosage cylinder 206 is threadedly connected to the pen barrel 1, and the screwing-in direction of the dosage cylinder 206 is the same as the direction of the fixed-axis one-way rotation of the stroke shaft 203.

[0067] The button 207 is provided at the top end of the pen barrel 1 and is used to apply an axial pressure to the limit clutch shaft 204; only when the button 207 is subjected to an axial pressure, the dosage cylinder 206 is in drivable connection with the limit clutch shaft 204.

[0068] When the dose barrel 206 sets the dose, that is, when the dose barrel 206 is screwed out, since the stroke shaft 203 can only rotate unidirectionally around its own axis along the screw-in direction of the dose barrel 206, when the dose barrel 206 is screwed out, the stroke shaft 203 has a limited rotation effect on the limit clutch shaft 204, and when the button 207 is not subjected to axial pressure, the end face teeth 2062 on the dose barrel 206 are not connected to the limit clutch shaft 204 in a transmission manner, and then as the dose barrel 206 is screwed out, the limit plate 205 is lifted to slide axially outward relative to the stroke shaft 203, and then the limit plate 205 drives the limit clutch shaft 204 to slide axially outward relative to the stroke shaft 203. During this process, the stroke shaft 203 does not rotate, so the screw 202 does not move either, and the process can smoothly complete the dose setting; when executing the injection dose barrel 206 to set the dose, the button 207 is pressed to force the dose barrel 206 to rotate. Since the dose barrel 206 is connected to the limit clutch shaft 204 through the end face teeth 2062, the limit plate 205 drives the clutch rotating shaft to rotate with the dose barrel 206. At this time, the cartridge bottle 213 has been installed in place, and the screw sleeve 201 rotates in conjunction with the stroke shaft 203, and then the screw 202 matched with the screw sleeve 201 screw will drive the rubber plug 2131 to push the drug in the cartridge bottle 213. In addition, the limit rib 2041 for limiting the displacement of the top end of the limit plate 205 is set on the limit clutch shaft 204, so that after the drug injection is completed, the injection pen dose barrel 206 cannot be adjusted.

[0069] In some embodiments, one of the outer wall of the stroke shaft 203 and the inner wall of the limit clutch shaft 204 is provided with an outer diameter groove, and the other is provided with a raised key platform, and the raised key platform is slidably matched with the outer diameter groove. In this embodiment, the outer diameter groove is provided on the outer wall of the stroke shaft 203, and the raised key platform is provided on the inner wall of the limit clutch shaft 204 as an example.

[0070] Furthermore, the present invention discloses that the outer diameter grooves and the raised key platforms correspond one to one, and both are in multiple numbers and are evenly distributed axially on the stroke shaft 203 and the limit clutch shaft 204 .

[0071] In some embodiments, the pusher assembly 2 further includes a transmission shaft 208, such as Figure 7 and Figure 8 As shown, the small shaft end of the transmission shaft 208 is sleeved in the limit clutch shaft 204, and the one-way ratchet on the small shaft end of the transmission shaft 208 is connected with the one-way ratchet on the limit clutch shaft 204 for one-way transmission, which is used for one-way transmission and auditory and tactile prompts during dose callback. The one-way ratchet on the small shaft end of the transmission shaft 208 is designed to be equally divided according to the dosage form requirements.

[0072] In some embodiments, the pusher assembly 2 further includes a gear sleeve 209, such as Figure 10As shown, the gear sleeve 209 is sleeved outside the large shaft end of the transmission shaft 208, and the one-way ratchet on the gear sleeve 209 is connected to the one-way ratchet on the large shaft end of the transmission shaft 208 in a one-way transmission manner. The one-way ratchet on the large shaft end of the transmission shaft 208 cooperates with the gear sleeve 209 for auditory and tactile prompts during dose setting. The one-way ratchet on the large shaft end of the transmission shaft 208 is designed to be equally divided according to the dosage form requirements.

[0073] The inner wall of the dose barrel 206 is snap-connected with the outer wall of the gear sleeve 209. Specifically, the inner hole at the top of the dose barrel 206 cooperates with the gear sleeve 209. The dose barrel 206 is guided by the rib position in the hole, and is assembled with the buckle position of the gear sleeve 209 through the buckle hole on the inner wall of the hole to form a whole, which is used for one-way transmission during dose setting and injection, and provides auditory and tactile prompts. When setting the dose, the limit clutch shaft 204, the rotating shaft and the limit plate 205 will produce a certain amount of axial runout. This runout is the height runout of the end face teeth 2062 at the bottom of the inner hole of the dose barrel 206 and the one-way ratchet teeth at the top of the limit clutch shaft 204. When injecting, the clutch teeth on the limit clutch shaft 204 and the end face teeth 2062 on the dose barrel 206 are set with a certain pressing force, which is in a tightly meshed state and will not produce runout, so as to achieve meshing transmission injection. A clearance distance is provided at the matching position between the transmission shaft 208 and the inner hole of the gear sleeve 209 so that when setting the dose, the axial bounce cannot contact the cross section of the gear sleeve 209 to prevent interference.

[0074] In some embodiments, the injection pen further comprises a window tube 3, such as Figure 13 and Figure 14 The window barrel 3 is fixed at the top of the pen barrel 1, and the scale value on the dosage barrel 206 can be seen through the window barrel 3. Specifically, the window barrel 3 is installed into the set position of the pen barrel 1 through the clamping position in the pen barrel 1.

[0075] Specifically, the dosage barrel 206 and the window barrel 3 are made of a material with a low friction coefficient, thereby reducing the wear of the window barrel 3 and the dosage barrel 206 on the pen barrel 1 .

[0076] The window tube 3 is made of a transparent material, or it may be made of a non-transparent material, and a window is provided on the window tube 3 for viewing the scale values ​​on the dosage tube 206 .

[0077] Specifically, the dosage tube 206 is made of POM (polyoxymethylene) material, and the window tube 3 is made of PBT (polybutylene terephthalate), PC (polycarbonate) or ABS (acrylonitrile-butadiene-styrene copolymer is a terpolymer composed of acrylonitrile, butadiene and styrene, a synthetic resin material).

[0078] In some embodiments, the pusher assembly 2 further includes a knob sleeve 210, such as Figure 9As shown in the figure. The knob sleeve 210 is sleeved outside the dose cylinder 206. A limiting convex post 2101 is provided at the top end inside the knob sleeve 210. The bottom end of the button 207 extends into the knob sleeve 210, and a limiting convex edge 2071 that can be engaged with the limiting convex post 2101 is provided on the outer wall of the bottom end of the button 207 to prevent the button 207 from slipping off axially.

[0079] A guide post 2072 is provided inside the button 207. A guide sleeve 2081 that is in guiding cooperation with the guide post 2072 is provided at the top end of the transmission shaft 208 to facilitate the guiding of the button 207.

[0080] Furthermore, the present invention discloses that a rib position with a protrusion 2063 is provided on the outer diameter of the top end of the dose cylinder 206 to cooperate with the inner hole groove of the knob sleeve 210. A circular structure with a recessed ring is provided on one side of the outer diameter of the dose cylinder 206 to cooperate with the annular structure of the protrusion 2063 at the mouth of the knob sleeve 210 to prevent the knob sleeve 210 from falling off.

[0081] In some embodiments, the propellant assembly 2 further includes a ratchet ring 211 and an elastic member 212. The ratchet ring 211 is sleeved inside the pen barrel 1 and is in one-way driving connection with the one-way ratchet on the end face of the step 101 of the pen barrel 1.

[0082] Specifically, a convex key is provided on the inner wall of the ratchet ring 211, and a key groove is provided on the outer wall of the stroke shaft 203. When injecting, the convex key is inserted into the key groove.

[0083] The elastic member 212 is sleeved outside the stroke shaft 203. The bottom end of the elastic member 212 abuts against the limiting ring at the bottom end of the stroke shaft 203, and the top end of the elastic member 212 abuts against the bottom end of the ratchet ring 211.

[0084] When setting the dose, the ratchet ring 211 cannot rotate. When injecting the drug, the ratchet ring 211 can rotate unidirectionally under the support of the elastic member 212. The key groove on the outer diameter of the stroke shaft 203 cooperates with the convex key in the inner hole of the ratchet ring 211. The unidirectional rotation performance of the ratchet ring 211 limits the stroke shaft 203 to always rotate unidirectionally only when setting the dose. When injecting, the key groove of the stroke shaft 203 drives the convex key in the inner hole of the ratchet ring 211 to rotate, and through the support of the elastic member 212 and the axial jump, it provides auditory and tactile cues. The one-way ratchet of the ratchet ring 211 and the one-way ratchet on the inner hole end face of the pen barrel 1 can be correspondingly equally divided according to different dosage forms of drugs.

[0085] Furthermore, the present invention discloses that the elastic member 212 is a spring. It should be noted that the elastic member 212 is not limited to being a spring and can also be other elastic components.

[0086] In some embodiments, a protrusion 2063 is provided at the bottom end of the dose cylinder 206, and the helix angle of the protrusion 2063 is the same as that of the pen barrel 1. When the dose cylinder 206 is screwed into the zero position, the protrusion 2063 is in a stop fit with the step 101 surface of the pen barrel 1. This ensures stopping at the zero position at the required location, prevents fitting interference, and achieves precise positioning of the zero position of the dose cylinder 206. Of course, it can be understood that the above structure is merely a preferred example of the embodiments of the present invention. In actual application, a groove can also be directly provided at the bottom end of the dose cylinder 206, and a protrusion 2063 can be provided on the step 101 surface of the pen barrel 1. In actual application, selection can be made according to actual needs.

[0087] In some embodiments, the screw rod 202 includes a threadless section 2021 and a threaded section 2022 whose first end is connected to the first end of the threadless section 2021, as Figure 19 shown. The push piece 2132 is installed at the second end of the threadless section 2021, and the screw rod sleeve 201 is installed at the first end of the threaded section 2022. The push piece 2132 cooperates with the screw rod 202 and can only rotate. There is a convex step 101 on the top surface of the conical structure at the end of the screw rod 202, which cooperates with the top surface of the inner hole of the push piece 2132 to prevent falling off. There is a U-shaped slot in the inner hole of the push piece 2132, and the elastic deformation amount is relied on to prevent the screw rod 202 from falling off after being installed. The threadless section 2021 on the screw rod 202 is used to limit the assembly position of the screw rod 202. This position cooperates with the propellant assembly 2 of the injection pen, and precise values can be taken to adapt to the drug loading amounts of different dosage forms. The threaded section of the screw rod 202 cooperates with the internal thread of the screw rod sleeve 201 to precisely control the displacement stroke of the screw rod 202. This thread can be designed into a structure with different pitches according to the requirements of the dosage form. For displacements requiring smaller doses, the screw rod 202 can be designed as a single-threaded screw, and for larger dosage form threads, it can be designed as a double-threaded screw to improve the precision of the screw rod 202.

[0088] In some embodiments, the present invention discloses that the injection pen further includes a cartridge 213. A rubber stopper 2131 is installed in the cartridge 213. The rubber stopper 2131 can slide axially along the cartridge 213. The rubber stopper 2131 is connected to the push piece 2132, and the rubber stopper 2131 is moved in the cartridge 213 by pushing the push piece 2132 through the screw rod 202.

[0089] In some embodiments, the present invention discloses that the injection pen further includes an injection needle 214. The injection needle 214 is installed at the bottom end of the cartridge 213 and is used for injecting drugs and the like.

[0090] In some embodiments, the present invention discloses that the injection pen further includes a pen core holder 215 and a pen cap 216. The pen core holder 215 is sleeved outside the cartridge 213, and the pen cap 216 is sleeved outside the pen core holder 215 and cooperates with the pen barrel 1 to enclose the entire propellant assembly 2.

[0091] In this text, the bottom end and the top end are set with the injection needle 214 facing downward when the injection pen is placed vertically, only for the convenience of description and without any other specific meaning. The above provides a detailed introduction to the injection pen provided by the present invention. It should be noted that each embodiment in this specification is described in a progressive manner, and the key point of each embodiment is to illustrate the differences from other embodiments. For the same and similar parts among the embodiments, reference can be made to each other.

[0092] It should also be noted that in this text, terms such as "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that an article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or further includes elements inherent to such article or device. Without further limitation, an element defined by the statement "including one..." does not exclude the existence of another identical element in the article or device including the above elements.

[0093] In this text, specific examples are used to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the core idea of the present invention. It should be pointed out that for those of ordinary skill in the art in this technical field, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. An injection pen, It is characterized in that It comprises a pen barrel and a propellant assembly arranged in the pen barrel; The pusher assembly includes a screw sleeve arranged in the pen barrel, a screw matched with the screw sleeve lead screw, a stroke shaft sleeved outside the screw, a limit clutch shaft sleeved outside the stroke shaft, a limit piece threadedly matched with the limit clutch shaft, a dosage barrel sleeved outside the limit clutch shaft, and a button arranged at the top of the pen barrel; The screw rod passes through the screw rod sleeve and is connected to the push piece of the cartridge bottle, and when the cartridge bottle is installed in place, the cartridge bottle can push the screw rod sleeve to link with the stroke shaft; The stroke shaft can rotate unidirectionally along its own axis, and an outer diameter rib is provided on the outer diameter of the bottom end of the stroke shaft, the outer diameter of the outer diameter rib is larger than the inner diameter of the hole on the step provided in the pen barrel, and the outer diameter rib is used to limit the displacement of the stroke shaft moving toward the top end of the pen barrel, the stroke shaft is limited in the limit clutch shaft along the axial direction of the limit clutch shaft, and the displacement of the stroke shaft relative to the axial sliding of the limit clutch shaft is a preset stroke displacement; A limiting groove for limiting the rotation of the limiting piece is arranged in the dosage barrel, and a supporting rib for supporting the bottom end of the limiting piece is arranged at the bottom end of the limiting groove, and a limiting rib for limiting the displacement of the top end of the limiting piece is also arranged on the limiting clutch shaft; The inner end surface of the bottom of the dosage barrel is provided with end face teeth which are clutch-connected to the limit clutch shaft, the dosage barrel is threadedly connected to the pen barrel, and the screwing direction of the dosage barrel is the same as the fixed axis unidirectional rotation direction of the stroke shaft; The button is used to apply axial pressure to the limit clutch shaft; when and only when the button is subjected to axial pressure, the dosage barrel is in driving connection with the limit clutch shaft; When the dosage barrel is rotated out, the limiting piece drives the limiting clutch shaft to slide outward relative to the stroke shaft axis.

2. The injection pen according to claim 1, It is characterized in that An outer diameter groove is provided on one of the outer wall of the stroke shaft and the inner wall of the limit clutch shaft, and a raised key platform is provided on the other, and the raised key platform is slidably matched with the outer diameter groove.

3. The injection pen according to claim 1, It is characterized in that The propellant assembly also includes a transmission shaft; The small shaft end of the transmission shaft is sleeved in the limit clutch shaft, and the one-way ratchet on the small shaft end of the transmission shaft is connected with the one-way ratchet on the limit clutch shaft in one-way transmission.

4. The injection pen according to claim 3, It is characterized in that The pusher assembly also includes a gear sleeve; The gear sleeve is sleeved outside the large shaft end of the transmission shaft, and the one-way ratchet on the gear sleeve is connected to the one-way ratchet on the large shaft end of the transmission shaft in one-way transmission; The inner wall of the dosage cylinder is snap-connected with the outer wall of the gear sleeve.

5. The injection pen according to claim 1, It is characterized in that Also included is a window tube; The window tube is fixed on the top end of the pen tube, and the scale value on the dosage tube can be seen through the window tube.

6. The injection pen according to claim 5, It is characterized in that The dosage tube and the window tube are both made of materials with low friction coefficient; The window cylinder is made of a transparent material; or The window cylinder is made of a non-transparent material, and a window is provided on the window cylinder through which the scale value on the dose cylinder can be seen.

7. The injection pen according to claim 3, characterized in that the propellant assembly further includes a knob sleeve; The knob sleeve is sleeved outside the dose cylinder. A limiting convex post is provided at the inner top end of the knob sleeve. The bottom end of the button extends into the knob sleeve, and a limiting convex edge capable of being clamped with the limiting convex post is provided on the outer wall of the bottom end of the button; A guide post is provided inside the button, and a guide sleeve for guiding and cooperating with the guide post is provided at the top end of the transmission shaft.

8. The injection pen according to claim 1, characterized in that the propellant assembly further includes a ratchet ring and an elastic member; The ratchet ring is sleeved inside the pen barrel and is in one-way driving connection with the one-way ratchet on the step end face of the pen barrel; A convex key is provided on the inner wall of the ratchet ring, and a key groove is provided on the outer wall of the stroke shaft. When injecting, the convex key is inserted into the key groove; The elastic member is sleeved outside the stroke shaft, and the bottom end of the elastic member abuts against the limiting ring at the bottom end of the stroke shaft, and the top end of the elastic member abuts against the bottom end of the ratchet ring.

9. The injection pen according to claim 1, characterized in that A protrusion is provided at the bottom end of the dose cylinder, and the spiral lift angle of the protrusion is the same as that of the pen barrel; When the dose cylinder is screwed into the zero position, the protrusion is in stop cooperation with the step surface of the pen barrel.

10. The injection pen according to any one of claims 1-9, characterized in that the screw includes a threadless section and a threaded section with a first end connected to the first end of the threadless section; The push piece is installed at the second end of the threadless section, and the screw sleeve is installed at the first end of the threaded section.

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