Injection pen

Abstract

The invention belongs to the field of medical instruments, and discloses an injection pen which enables production cost to be remarkably reduced and comprises a medicine carrying container, a medicine feeding push rod, a driving entity and a base shell, the medicine carrying container is provided with a push rod inlet, the driving entity is provided with a push rod containing groove, and the medicine feeding push rod is inserted into the push rod containing groove in a matched mode. The driving entity and the medicine carrying container are located on the two opposite sides of the medicine feeding push rod respectively, the base shell is provided with a containing cavity, the push rod inlet is communicated with the containing cavity, the medicine feeding push rod is inserted into the medicine carrying container, the driving entity is inserted into the base shell and can move relative to the base shell, the circumferential face of the medicine feeding push rod is provided with a sawtooth section, and sawteeth of the sawtooth section are provided with tooth inclined faces and tooth planes. The containing cavity extends to form a first stopping elastic piece, the first stopping elastic piece forms a first stopping face, the first stopping face is matched with the tooth plane in a veneering mode, the driving entity extends to form a second stopping elastic piece, the second stopping elastic piece forms a second stopping face, and the second stopping face is matched with the tooth plane in a veneering mode.

Description

Technical Field

[0001] This invention belongs to the field of medical devices, specifically relating to an injection pen. Background Technology

[0002] Currently, injection pens are widely used in the treatment of chronic diseases such as diabetes and growth hormone deficiency because they allow patients to administer medication themselves. Traditional injection pens are typically assembled from multiple precision parts, including the pen body, dosage setting mechanism, drive mechanism, injection button, vial holder, and needle connector.

[0003] Chinese utility model patent discloses a manually operated insulin injection pen (publication number: CN 220404565U), representing a typical current injection pen product. It includes a shell, inside which is a scale adjustment sleeve. The upper part of the scale adjustment sleeve is a grip, located above the shell. From top to bottom, an activation button, a locking lever, and a spring are sequentially installed on the inner side of the upper part of the scale adjustment sleeve. An adjusting screw sleeve and a push rod are connected to the inner side of the scale adjustment sleeve. The lower part of the adjusting screw sleeve is connected to an adjusting nut, which is fixed inside the lower part of the shell. A rear cover is fixed below the adjusting nut, and a screw rod passes through the rear cover. The screw rod is slidably connected to the push rod, and the push rod is slidably connected to the locking lever. The scale adjustment sleeve is slidably connected to the adjusting screw sleeve. The specification discloses its implementation method: when the patient needs an injection, first adjust the injection dose… hold the shell 2 with one hand and the scale adjustment sleeve with the other, rotate the adjustment sleeve in a spiral upward motion… read the adjusted scale… The above corresponds to a type of product such as… Figure 1 In practical applications, when the above-mentioned product is implemented in its initial state, the distance between the top of the adjustment sleeve and the top of the outer shell is greater than 30mm, that is, the distance between the user's thumb and index finger is greater than 30mm.

[0004] The existing technology has the following shortcomings in implementation: 1) It requires a large number of parts and numerous injection molds for individual molding, thus preventing further reduction in production costs. 2) The assembly from parts to the finished product is also cumbersome, further hindering cost reduction. 3) The large number of parts increases the probability of assembly errors and product malfunctions during assembly. 4) The significant distance between the top of the adjusting sleeve and the top of the outer shell results in a poor grip experience for the user. 5) Because the dosage needs to be adjusted with precision, this not only reduces the user experience but also lowers medication safety due to potential user health issues (such as elderly people with poor coordination, visual or cognitive impairments), or user negligence leading to significant dosage deviations. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides an injection pen that reduces the number of required parts and simplifies product assembly, thereby significantly reducing production costs.

[0006] To achieve the above objectives, the present invention provides the following technical solution: An injection pen includes a drug-loaded container with a rodless piston and a drug delivery opening. The rodless piston is movably disposed inside the drug-loaded container, and the direction of movement of the rodless piston is used as the drug delivery direction, which is perpendicular to the rodless piston. The pen is characterized by further comprising: a drug delivery push rod extending along the drug delivery direction; a driving entity having a push rod receiving groove open at one end, a portion of the drug delivery push rod being inserted into the push rod receiving groove; and the driving entity and the drug-loaded container being located on opposite sides of the drug delivery push rod along the drug delivery direction; a base shell having a receiving cavity, with a container coupling port and a entity penetration port at both ends in the drug delivery direction; the drug-loaded container also having a push rod inlet, which is coupled to the container... The corresponding openings are connected, and the drug delivery push rod enters the drug-carrying container through the push rod inlet. The driving entity is inserted into the base shell through the entity throughlet and is movable relative to the base shell. The drug delivery push rod has serrated segments extending along the drug delivery direction on opposite sides of its circumference. The serrated segments have toothed surfaces and toothed surfaces. The toothed surfaces are inclined relative to the drug delivery direction, and the toothed surfaces are perpendicular to the drug delivery direction. The receiving cavity extends along the drug delivery direction to form a first stop spring. The free end of the first stop spring has a first stop surface that fits against the toothed surface. The driving entity extends along the drug delivery direction to form a second stop spring. The free end of the second stop spring has a second stop surface that fits against the toothed surface.

[0007] Preferably, the free end of the second stop spring is further provided with a second sliding surface, which is bent continuously with the second stop surface and is in contact with the toothed helical surface.

[0008] Preferably, the peripheral surface of the driving entity is formed with a locking flange, and the base shell is formed with a stop surface and a limiting step surface located in the receiving cavity. The stop surface and the limiting step surface are parallel and the distance between them is a predetermined distance. The limiting step is used to block the locking flange, and the stop surface has a push rod through hole for the drug delivery push rod. The second stop surface cannot enter the push rod through hole. Preferably, the drive body also forms a locking flange protruding into the push rod groove, and the end of the drug delivery push rod away from the drug container has a limit stop surface, which is used to block the locking flange.

[0009] Furthermore, a mold exit is formed on the peripheral surface of the driving entity, and the mold exit is located near the locking flange.

[0010] Furthermore, recessed straight grooves are formed on opposite sides of the circumference of the drug delivery push rod along the drug delivery direction, so that the cross-section of the drug delivery push rod is "I" shaped and the bottom surface of the recessed straight groove forms a serrated section.

[0011] Furthermore, there is a pair of second stop springs. The free ends of the pair of second stop springs face each other and form a second passage interval. The locking flange forms a first passage interval in the push rod groove. The side wall of the recessed straight groove is used as a serrated edge. The first passage interval and the second passage interval are both smaller than the width of the serrated edge. The serrated edge has a first clearance notch and a second clearance notch. The free end of the second stop spring enters the recessed straight groove through the first clearance notch and cooperates with the tooth plane. The locking flange enters the recessed straight groove through the second clearance notch.

[0012] Preferably, the driving entity has an integrally continuous rod portion and a seat portion along the drug administration direction. The orthographic projection of the seat portion along the drug administration direction is larger than that of the rod portion. The seat portion has a seat inner hole extending along the drug administration direction. The rod portion forms a push rod receiving groove, and the push rod receiving groove is correspondingly connected to the seat inner hole, so that one end of the drug administration push rod is inserted into the seat inner hole.

[0013] Furthermore, the present invention also includes a pen cover and a pen refill holder tube. The pen cover is fitted over the outside of the base shell. A locking through hole is formed on the edge of the pen cover away from the driving entity. Part of the drug-carrying container is located outside the pen cover. The pen refill holder tube and the driving entity are located on opposite sides of the drug delivery push rod along the drug delivery direction. The pen refill holder tube is hollow and has a locking protrusion inside that cooperates with the locking through hole. The pen refill holder tube is fitted over the outside of the drug-carrying container.

[0014] Furthermore, the present invention also includes a pen cap, which covers the outside of the pen refill tube holder and engages with the pen cover shell.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. Because the injection pen of the present invention includes a drug-loaded container, a drug delivery plunger, a driving entity, and a base shell, the drug-loaded container has a plunger inlet, the driving entity has a plunger receiving groove, the drug delivery plunger is inserted into the plunger receiving groove, and the driving entity and the drug-loaded container are respectively located on opposite sides of the drug delivery plunger, the base shell has a receiving cavity, the plunger inlet communicates with the receiving cavity, the drug delivery plunger is inserted into the drug-loaded container, the driving entity is inserted into the base shell and is movable relative to the base shell, the peripheral surface of the drug delivery plunger has a serrated section, the serrations of the serrated section have tooth bevels and tooth planes, and the receiving cavity extends to form a first stop spring. The first stop spring has a first stop surface that engages with the toothed surface. The driving entity extends to form a second stop spring, which has a second stop surface that engages with the toothed surface. When the user applies external force to the driving entity, the driving entity, through the engagement of a serrated toothed surface with the second stop surface, moves the drug delivery pusher within the base shell. This pusher then pushes the rodless piston within the drug delivery container, achieving single-dose administration. At this time, the first stop surface engages with the toothed surface of another serrated surface, realizing the operation of the drug delivery pusher. The second stop spring slides in the opposite direction on the toothed surface when the user applies external force to the driving entity, and the drug delivery push rod stops in the opposite direction, thereby realizing the reset action of the driving entity and preventing the drug delivery push rod from moving in the opposite direction. Thus, it is possible to administer a predetermined dose of drug to the drug-carrying container multiple times. Therefore, the present invention reduces the required parts, that is, it no longer needs complex digital dials, gear transmission systems and other components, the structure is simpler, the product assembly is simplified, thereby reducing the probability of potential failure points during the assembly process, thus making the product more reliable and significantly reducing the production cost. Moreover, the operation of the present invention is intuitive and conforms to the direct mapping of "pull as much as you need". The user only needs to perform a simple linear pulling action to realize the drug delivery action, thus avoiding the abstract relationship between the "rotation" action of the adjustment sleeve and the "dosage digital change" and "internal screw mechanical movement" that the user needs to understand in the prior art. This greatly reduces the learning cost and memory burden, and is especially suitable for specific uses, especially in emergency situations, or when operated by non-professional nursing personnel.

[0016] 2. Because the driving body of the injection pen of the present invention has a locking flange formed on its peripheral surface, and the base shell has a stop surface and a limiting step surface located in the receiving cavity, the stop surface and the limiting step surface are parallel and the distance between them is a predetermined distance. The limiting step is used to block the locking flange, and the stop surface has a push rod through hole for the drug delivery push rod. The second stop surface cannot enter the push rod through hole, so the movement stroke of the driving body can be accurately controlled within a predetermined distance each time. Therefore, the present invention can achieve precise single-dose drug delivery, that is, the maximum single-dose drug delivery is locked at a predetermined dose (i.e., the drug delivery dose corresponding to the predetermined distance) through physical limiting (hard stop). This mechanically eliminates the possibility of injecting an excessive dose due to user misoperation (such as over-rotation in the prior art), and the safety is extremely high. At the same time, because there is no need for the complex digital window indicating the drug delivery dose in the prior art, the risk caused by possible physical reasons of the user (such as the elderly with poor coordination, visual or cognitive impairment) or large dose deviation caused by user negligence is completely eliminated. That is, the dose setting is purely guaranteed by the mechanical action itself, which is simple and reliable.

[0017] 3. Because the driving entity of the present invention also forms a locking flange protruding into the push rod groove, and the end of the drug delivery push rod away from the drug-loaded container has a limit stop surface, which is used to block the locking flange, when the drug delivery push rod completely delivers the predetermined dose of drug in the drug delivery container, the limit stop surface will block the locking flange, and the drug delivery push rod cannot move in reverse, so the driving entity cannot reset. Therefore, after the present invention completely delivers the predetermined dose of drug in the drug delivery container, it cannot reset again. Thus, the present invention can strictly limit the drug delivery to a single drug-loaded container and prevent the user from using two or more drug-loaded containers for drug delivery.

[0018] 4. Because the drug delivery push rod of the present invention has recessed straight grooves formed on opposite sides of its circumference along the drug delivery direction, the cross-section of the drug delivery push rod is "I" shaped. The bottom surface of the recessed straight groove forms a serrated segment, which is located inside the recessed straight groove. The side wall of the recessed straight groove can be used to form a limit stop surface. Therefore, the serrations and stop surface of the present invention are not exposed, so the shape can be better protected. Moreover, the space restriction in the groove can make the tooth shape better fit with the first stop spring, the second stop spring, and the limit stop surface and the locking flange, thereby avoiding the relative displacement of the relevant mating surfaces during the motion transmission process.

[0019] 5. Because the driving entity of the present invention has an integrally continuous rod and seat portion along the drug administration direction, the orthographic projection of the seat portion in the drug administration direction is larger than that of the rod portion, and the seat portion has a seat inner hole extending along the drug administration direction, and the rod portion forms a push rod receiving groove, and the push rod receiving groove is correspondingly connected to the seat inner hole, so that one end of the drug administration push rod is inserted into the seat inner hole, the coupling strength between the driving entity and the drug administration push rod of the present invention is better. Attached Figure Description

[0020] Figure 1 This is a handheld implementation diagram of a prior art injection pen.

[0021] Figure 2 This is a schematic diagram of an injection pen according to an embodiment of the present invention.

[0022] Figure 3 for Figure 2 Exploded view.

[0023] Figure 4 This is a schematic diagram of the drug delivery pusher according to an embodiment of the present invention.

[0024] Figure 5 for Figure 4 Enlarged schematic diagram of part A in the middle.

[0025] Figure 6(a) is a schematic diagram of the driving entity of an embodiment of the present invention. Figure 1 .

[0026] Figure 6(b) is a schematic diagram of the driving entity of an embodiment of the present invention. Figure 2 .

[0027] Figure 7 This is a cross-sectional view of the drive entity at the locking flange in an embodiment of the present invention (in conjunction with the drug delivery push rod, and only a portion of the drive entity is shown).

[0028] Figure 8 This is a schematic diagram of the base shell of an embodiment of the present invention.

[0029] Figure 9 This is a schematic diagram illustrating the assembly of the driving entity, the drug delivery push rod, and the base shell according to an embodiment of the present invention.

[0030] Figure 10 for Figure 9 Color illustrations.

[0031] Figure 11 This is a schematic diagram of a pen cover half-shell according to an embodiment of the present invention.

[0032] Figure 12 This is a schematic diagram of a pen refill holder according to an embodiment of the present invention.

[0033] Figure 13(a) shows the first implementation state (injection) of the injection pen according to an embodiment of the present invention.

[0034] Figure 13(b) shows the second implementation state (reset) of the injection pen according to an embodiment of the present invention.

[0035] Figure 13(c) shows the third implementation state (locked) of the injection pen according to an embodiment of the present invention.

[0036] In the diagram: 100, injection pen; 10, drug-loaded container; 10a, drug delivery opening; 10b, push rod inlet; 11, rodless piston; D, drug delivery direction; 20, drug delivery push rod; 20a, recessed straight groove; 20b, serrated retaining edge; 20c, limit stop surface; 20d, first clearance notch; 20e, second clearance notch; 20f, push rod top; 21, serrated section; 211, serration; 211a, tooth plane; 211b, tooth bevel; 30, driving entity; 31, rod portion; 31a, push rod receiving groove; 31b, locking flange; 31c, mold outlet; 31d, locking flange; 311, second stop spring; 311a, second stop surface; 311b, second sliding surface; 32, seat portion; 32a, seat inner hole; 32b, button weld. 40A, Base shell, 41, Receiving cavity, 41a, Container coupling port, 41b, Solid penetration entrance, 41c, Stop stop surface, 41d, Push rod through hole, 41e, Limiting step surface, 411, Spring piece movable sub-cavity, 412, First stop spring piece, 412a, First stop surface, 412b, First sliding surface, 413, Partition solid, 40B, Sealing plate, 50, Pen cover shell, 50a, Pen cover half shell, 50b, Connecting step, 51, Closing tube end, 511, Hollowed-out part, 511a, Coupling spring piece, 511b, Fastening protrusion, 511c, Fastening through hole, 60, Pen refill holder tube, 61, Fastening part, 61a, Fastening protrusion, 61b, Fastening groove, 62, Observation window, 70, Pen cap, 71, Cap tongue, 80, Force application button. Detailed Implementation

[0037] To make the technical means, creative features, objectives and effects of the present invention easier to understand, the following embodiments, in conjunction with the accompanying drawings, specifically illustrate the injection pen of the present invention. It should be noted that the description of these embodiments is for the purpose of helping to understand the present invention, but does not constitute a limitation of the present invention.

[0038] like Figure 2 and Figure 3 As shown, the injection pen 100 in this embodiment includes a drug-carrying container 10, a drug delivery pusher 20, a driving entity 30, a base shell 40A, a pen cover shell 50, a pen refill holder tube 60, and a pen cap 70. Specifically, the injection pen 100 also includes a sealing plate 40B and a force-applying button 80. In this embodiment, the injection pen 100 extends in a straight line.

[0039] The drug-carrying container 10 is a transparent straight tube with openings at both ends. The openings at both ends are a drug delivery opening 10a and a push rod inlet 10b, respectively. A rodless piston 11 is movably disposed inside the container along its own extension direction. The movement direction of the rodless piston 11 is taken as the drug delivery direction D. The drug delivery direction D is perpendicular to the rodless piston 11, that is, the drug delivery direction D is also the extension direction of the drug-carrying container 10. In this embodiment, the drug delivery direction D is also the extension direction of the injection pen. Specifically, the drug-loaded container 10, the drug delivery push rod 20, and the driving entity 30 are sequentially distributed and coupled in pairs along the drug delivery direction D. Inside the drug-loaded container 10, a predetermined dose of drug is pre-filled between the rodless piston 11 and the drug delivery opening 10a. The driving entity 30 drives the drug delivery push rod 20 to move within the drug-loaded container 10, thereby pushing the rodless piston 11 to deliver the pre-filled drug to the user. In this embodiment, the predetermined dose of drug is not a single dose, but a dose for multiple doses.

[0040] like Figure 4 As shown, the drug delivery push rod 30 extends along the drug delivery direction D. The drug delivery push rod 20 has a recessed straight groove 20a, a serrated edge 20b, a limit stop surface 20c, a first clearance notch 20d, a second clearance notch 20e, a push rod top 20f, and a serrated section 21.

[0041] Specifically, the end of the drug delivery push rod 20 near the rodless piston 11 is enlarged to form a push rod head 20f, so that the drug delivery push rod 20 pushes the rodless piston 11 through the push rod head 20f.

[0042] A pair of recessed straight grooves 20a extend along the drug delivery direction D and are closed at both ends. They are formed on opposite sides of the circumferential surface of the drug delivery push rod 20, thus giving the cross-section of the drug delivery push rod 20 an "I" shape (see details). Figure 8 Specifically, one end of the recessed straight groove 20a is closed by the push rod top 20f.

[0043] The opposite sidewalls of the recessed straight groove 20a are used as serrated edging 20b, and the serrated edging 20b is a pair of sidewalls extending along the drug delivery direction D. The serrated edging 20b has a first clearance notch 20d and a second clearance notch 20e. The end sidewall of the drug delivery push rod 20 away from the drug delivery container 10 is used as the limit stop surface 20c. The serrated segment 21 is formed on the bottom surface of the recessed straight groove 20a and is composed of a plurality of serrations 211 arranged sequentially adjacent to each other along the drug administration direction D. In this embodiment, both ends of each serration 211 intersect with the serrated edge 20b.

[0044] like Figure 5 As shown, the serration 211 has a continuously bent, acute-angled tooth bevel 211b and a tooth plane 211a. The tooth bevel 211b is inclined relative to the drug administration direction D, and the tooth plane 211a is perpendicular to the drug administration direction d. Specifically, the tooth bevel 211b faces the push rod tip 20f, and the tooth plane 211a faces the limit stop surface 20c. In this embodiment, the tooth plane 211a and the limit stop surface 20c are parallel.

[0045] As shown in Figure 6(a) to Figure 7As shown, the driving entity 30 has a seat portion 32 and a rod portion 31 that are integrally continuous in the drug delivery direction D toward the drug delivery container 10, and the driving entity 30 and the drug delivery container 10 are located on opposite sides of the drug delivery push rod 20 in the drug delivery direction D.

[0046] The orthographic projection of the seat portion 32 along the drug administration direction D is greater than that of the rod portion 31, and the seat portion 32 has an inner hole 32a extending along the drug administration direction D. One end of the inner hole 32a is open toward the rod portion 31, and the other end is closed. Specifically, the free end of the seat portion 32 forms a button welding area 32b for welding the force-applying button 80.

[0047] The rod portion 31 has a push rod receiving groove 31a extending along the drug administration direction D. One end of the push rod receiving groove 31a is open at the free end of the rod portion 31, and the other end communicates with the seat inner hole 32a. Thus, a part of the drug administration push rod 20 is inserted into the inside of the push rod receiving groove 31a, and the end of the drug administration push rod 20 inside the push rod receiving groove 31a is inserted into the seat inner hole 32a. Specifically, the cross-section of the seat inner hole 32a is larger than the cross-section of the push rod receiving groove 31a. During assembly, the drug administration push rod 20 is first inserted into the seat inner hole 32a, and then pushed into the corresponding push rod receiving groove 31a.

[0048] The free end of the rod 31 is formed with a locking flange 31b, and the surface of the locking flange 31b extends along the administration direction D to form a second stop spring 311. There is a pair of second stop springs 311, the free ends of the pair of second stop springs 311 face each other and approach each other, and a second passage interval is formed between the pair of second stop springs 311 (not shown in the figure).

[0049] The free end of the second stop spring 311 has a second stop surface 311a and a second sliding surface 311b formed by a continuous acute-angle bend. The second stop surface 311a is in contact with the tooth plane 211a, and the second sliding surface 311b is in contact with the tooth inclined surface 211b. Specifically, when the driving entity 30 moves along the drug delivery direction D, since the force transmission surface of the second stop surface 311a and the tooth plane 211a is perpendicular to the drug delivery direction D, the driving entity 30 can drive the drug delivery push rod 20 to move toward the drug container 10. When the driving entity 30 moves in the opposite direction along the drug delivery direction D, if the drug delivery push rod 20 is stationary due to external constraints, since the force transmission surface of the second sliding surface 311b and the tooth inclined surface 211b is inclined relative to the drug delivery direction D, the driving entity 30 can decouple and slide relative to the drug delivery push rod 20 toward the drug container 10 in the opposite direction.

[0050] The inner wall of the push rod receiving groove 31a also forms a mold outlet 31c that connects the inside of the groove with the outside and an inwardly protruding locking flange 31d.

[0051] The mold exit 31c is located near the locking flange 31d. The locking flange 31d forms a first passage interval (not shown in the figure) in the push rod receiving groove 31a. Both the first passage interval and the second passage interval are smaller than the width of the serrated edge 30b. Specifically, when the drug delivery push rod 20 is assembled into the push rod receiving groove 31a, the free end of the second stop spring 311 enters the recessed straight groove 20a through the first clearance notch 20d and cooperates with the toothed plane 211a. The locking flange 31d enters the recessed straight groove 20a through the second clearance notch 20e. When the drug delivery push rod 20 moves relative to the push rod receiving groove 31a, and the limit stop surface 20c blocks the locking flange 31d, the drug delivery push rod 20 will not be able to continue moving toward the drug delivery container 10. The mold exit 31c is designed to enable the locking flange 31d to be injection molded.

[0052] like Figures 8 to 10 As shown, the base shell 40A has a receiving cavity 41.

[0053] The receiving cavity 41 has a container coupling port 41a and a solid penetration port 41b at both ends in the drug delivery direction D. The push rod inlet 10b is connected to the container coupling port 41a, so that the drug delivery push rod 20 enters the drug-loaded container 10 through the push rod inlet 10b. The driving entity 30 is inserted into the base shell 40A through the solid penetration port 41b, and the driving entity 30 is movable relative to the base shell 40A in the drug delivery direction D.

[0054] A stop surface 41c and a limiting step surface 41e are formed on the inner wall of the receiving cavity 41. The stop surface 41c and the limiting step surface 41e are parallel and the distance between them is a predetermined distance. The limiting step surface 41e is used to block the locking flange 31b. The stop surface 41c has a push rod through hole 41d for the drug delivery push rod 20 to pass through. The second stop surface 311a cannot enter the push rod through hole 41d. Specifically, the stop surface 41c and the limiting step surface 41e separate the spring piece movable sub-cavity 411 in the receiving cavity 41. The stop surface 41c is used to block and limit the second stop surface, and the limiting step surface 41e is used to block and limit the locking flange 31b. Thus, the movement space of the driving entity 30 in the receiving cavity 41 is limited to the spring piece movable sub-cavity 411. That is, the maximum stroke of the driving entity 30 in the base shell 40A along the drug delivery direction D is only a predetermined distance.

[0055] The receiving cavity 41 extends along the drug delivery direction D to form a first stop spring 412. There is a pair of first stop springs 412, with their free ends facing each other. The free ends of the first stop springs 412 form a first stop surface 412a and a first sliding surface 412b. The first stop surface 412a and the second stop surface 311a, the first sliding surface 412b and the second sliding surface 311b are all parallel to the drug delivery direction D. Specifically, the first stop surface 412a is in contact with the tooth plane 211a, and the first sliding surface 412b is in contact with the tooth inclined surface 211b. Specifically, when the driving entity 30 drives the drug delivery push rod 20 along the drug delivery direction D... When moving in direction D, since the force transmission surfaces of the second sliding surface 311b and the toothed surface 211b are inclined relative to the drug delivery direction D, the second sliding surface 311b and the toothed surface 211b can be decoupled, that is, the drug delivery push rod 20 can move relative to the base shell 40A toward the drug container 10; when the driving entity 30 moves in the opposite direction along the drug delivery direction D, since the force transmission surfaces of the first stop surface 412a and the toothed surface 211a are perpendicular to the drug delivery direction D, the first stop surface 412a and the toothed surface 211a cannot be decoupled, that is, the first stop spring 412 stops the drug delivery push rod 20 in the opposite direction, that is, the above-mentioned "if the drug delivery push rod 20 is stationary due to external constraints".

[0056] Specifically, the drug delivery push rod 20 can only move unidirectionally toward the drug-carrying container 10 within the receiving cavity 41, while the driving entity 30 can move bidirectionally along the drug delivery direction D within the receiving cavity 41, but the maximum travel distance is a predetermined distance.

[0057] In this embodiment, a partition entity 413 is also formed inside the receiving cavity 41. The stop surface 41c is the end face of the partition entity 413 facing the limiting step surface 41e, and a first stop spring piece 412 is formed on the other end face of the partition entity 413.

[0058] Specifically, the base shell 40A and the sealing plate 40B cooperate with each other to enclose the entire circumference of the driving entity 30.

[0059] like Figure 11 As shown, the pen cover 50 is fitted over the outside of the base shell 40A. The edge of the pen cover 50 away from the driving entity has a locking through hole 511c. Part of the drug-carrying container 10 is located outside the pen cover 50. Specifically, the pen cover 50 is formed by a pair of pen cover half shells 50a that are interlocked, thereby completely enclosing the entire structure formed by the base shell 40A and the sealing plate 40B. The pen cover 50 has openings at both ends in the drug delivery direction D. The seat portion 32 of the driving entity 30 extends out from one opening, and the other opening forms a constricted end 51.

[0060] Specifically, a hollow portion 511 is formed on the closing cylinder end 51. A coupling elastic piece 511a is formed in the hollow portion 511. The coupling elastic piece 511a extends along the circumferential direction of the closing cylinder end 51. The coupling elastic piece 511a maintains a gap with the solid portion of the closing cylinder end 51. Thus, a buckling through hole 511c in a shape of "匚" is formed near the coupling elastic piece 511a on the closing cylinder end 51. Moreover, a buckling convex edge 511b is formed at the elastic free end of the coupling elastic piece 511a.

[0061] As Figure 12 shown, the pen core tube holder 60 and the driving entity 30 are respectively located on opposite sides of the drug delivery push rod 20 along the drug delivery direction D. The pen core tube holder 60 is hollow and has a buckling convex block 61a inside that cooperates with the buckling through hole 511c. Moreover, the pen core tube holder 60 is sleeved outside the drug carrier container 10. Specifically, one end of the drug carrier container 10 is inserted into the closing cylinder end 51, and the drug carrier container 10 exposed from the pen cover 50 is completely sleeved by the pen core tube holder 60.

[0062] Specifically, the inner wall of the pen core tube holder 60 has a buckling portion 61 corresponding to the hollow portion 511. The buckling portion 61 is formed with a buckling convex block 61a and a buckling groove 61b. The buckling groove 61b cooperates with the buckling convex edge 511.

[0063] Specifically, an open observation window 62 is further formed on the circumferential surface of the pen core tube holder 60. The pen core tube holder 60 further has an injection port (not shown in the drawings) that communicates with the drug delivery opening 10a.

[0064] The pen cap 70 is sleeved outside the pen core tube holder 60, and the pen cap 70 cooperates with the pen cover 50. Specifically, when the injection pen 100 is not in use, the pen cap 70 encloses and covers the pen core tube holder 60. When the injection pen 100 is in use, the pen cap 70 is removed from the pen cover 50, thereby exposing the pen core tube holder 60, and a drug delivery operation is performed through the injection port. In this embodiment, the edge of the pen cap 70 has a cap tongue 71 extending towards the pen cover 50, and the edge of the pen cover 50 has a joint step 50b that cooperates with the cap tongue 71.

[0065] Specifically, the force - applying tab 80 is welded and adhered to the tab welding area 32b of the seat portion 32 of the driving entity 30. The exposed surface of the force - applying tab 80 is arc - shaped and is used for the human thumb to press on it, so as to move the driving entity D along the drug delivery direction D.

[0066] When the injection pen 100 is in the initial state before starting to be used, the push rod head 20f contacts the rodless piston 11.

[0067] As shown in Fig. 13(a), the injection pen 100 in the injection state will be described below in combination with the embodiments: The user holds the pen cover 50 with four fingers (excluding the thumb) around its periphery, and presses the force-applying button 80 with the pad of the thumb to push the drive body 30 to move relative to the base shell 40A. At the same time, the drug delivery push rod 20 is moved. When the locking flange 31b of the drive body 30 moves from the limiting step surface 41a to the stop surface 41c where it is blocked, the drug delivery push rod 20 pushes the rodless piston 11 a predetermined distance, thereby completing a single drug delivery with the injection pen 100.

[0068] As shown in Figure 13(b), the injection pen 100 in the reset state will be described below with reference to the embodiment: After at least one administration, if the remaining amount of drug in the drug container 10 is sufficient for at least one more administration, the injection pen 100 needs to be reset. The user does not change the grip of the injection pen 100 and moves the driving entity 30 in the opposite direction with the thumb (in this embodiment, the tail end of the seat 32 of the driving entity 30 is formed with a tapered end whose cross-section gradually increases outward. When resetting, the user moves in the opposite direction by pressing against the circumference of the tapered end with the thumb). At this time, although the driving entity 30 can move back, the drug delivery push rod 20 cannot move back due to the reverse restriction stop of the base shell 40A. Furthermore, since the stop surface 41c and the limiting step surface 41e limit the maximum stroke of the driving entity 30 by blocking, when the driving entity 30 is performing a single drug delivery or a resetting operation, it can obtain a clear and definite tactile feedback that the single drug delivery or drug delivery resetting is completed through physical blocking resistance, without having to observe the scale as in the prior art, thus completing precise drug delivery or resetting.

[0069] As shown in Figure 13(c), the following description, in conjunction with an embodiment, illustrates the injection pen 100 in a locked state: If there is no remaining drug in the drug container 10, the injection pen 100 must not be replaced without replacing the drug container 100. In order to prevent the user from still being able to use the injection pen 100 in this situation, the injection pen 100 forms a blocking limit on the limit stop surface 20c on the peripheral surface of the drug delivery push rod 20 by the locking flange 31d on the drive body 30. Thus, the drug delivery push rod 20 cannot move in any direction of drug delivery D and is in a locked state, thereby ensuring that the injection pen 100 cannot continue to deliver drugs in this state.

[0070] Specifically, compared to existing technologies, the injection pen 100 only requires two actions: "removing the pen cap 70 and pushing or pulling the driving entity 30 in a straight line until it can no longer be pushed or pulled." Compared to existing technologies that require rotating several times to set the dosage, the operation speed is significantly improved. Obviously, this is more practical for rapid self-rescue scenarios, such as emergency situations requiring rapid injection, such as severe hypoglycemia. Furthermore, because it is a straight push or pull, the difference between the corresponding ends of the driving entity 30 and the pen cover 50 is only about 10mm. That is, the distance between the user's thumb and the index finger holding the injection pen 100 is only about 10mm, which is far less than the "greater than 30mm" of existing technologies. Therefore, it is better than existing technologies in terms of ergonomics, safety, and user experience.

[0071] The above embodiments are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Various modifications or variations that can be made by those skilled in the art without creative effort within the scope of the appended claims are still within the scope of protection of this patent.

Claims

1. An injection pen comprising a drug-loaded container having a rodless piston and a drug delivery opening, said rodless piston being movably disposed inside said drug-loaded container, the direction of movement of said rodless piston being taken as the drug delivery direction, which is perpendicular to said rodless piston, characterized in that, Also includes: The drug delivery plunger extends along the drug delivery direction. The driving entity has a push rod receiving groove open at one end, and a portion of the drug delivery push rod is inserted into the push rod receiving groove. The driving entity and the drug delivery container are located on opposite sides of the drug delivery push rod along the drug delivery direction. The base shell has a receiving cavity, and the receiving cavity has a container coupling port and a solid penetration port at both ends in the drug delivery direction. The drug-carrying container also has a push rod inlet, which is correspondingly connected to the container coupling port. The drug delivery push rod enters the drug-carrying container through the push rod inlet. The driving entity is inserted into the base shell through the solid penetration port and is movable relative to the base shell. The drug delivery pusher has serrated segments extending along the drug delivery direction on opposite sides of its circumference. Each serrated segment has a beveled surface and a flat surface; the beveled surface is inclined relative to the drug delivery direction, and the flat surface is perpendicular to the drug delivery direction. The receiving cavity extends along the drug delivery direction to form a first stop spring, the free end of which has a first stop surface that mates with the toothed plane. The driving entity extends along the drug delivery direction to form a second stop spring, the free end of which has a second stop surface that mates with the tooth plane.

2. The injection pen according to claim 1, characterized in that: wherein The free end of the second stop spring is also formed with a second sliding surface, which is bent and continuous with the second stop surface and is in contact with the toothed inclined surface.

3. The injection pen according to claim 1, characterized in that: wherein, The driving entity has a locking flange on its peripheral surface, and the base shell has a stop surface and a limiting step surface located in the receiving cavity. The stop surface and the limiting step surface are parallel and spaced apart by a predetermined distance. The limiting step is used to block the locking flange, and the stop surface has a push rod through hole for the drug delivery push rod to pass through. The second stop surface cannot enter the push rod through hole.

4. The injection pen according to claim 1, characterized in that: wherein The drive body also forms a locking flange protruding into the push rod groove, and the end of the drug delivery push rod away from the drug container has a limit stop surface, which is used to block the locking flange.

5. The injection pen according to claim 4, characterized in that: wherein A mold exit opening is also formed on the peripheral surface of the driving entity, which is located near the locking flange.

6. The injection pen according to claim 4, characterized in that: wherein The drug delivery push rod has recessed straight grooves formed on opposite sides of its circumference along the drug delivery direction, so that the cross-section of the drug delivery push rod is "I" shaped, and the bottom surface of the recessed straight groove forms the serrated section.

7. The injection pen according to claim 6, characterized in that: wherein The number of the second stop springs is one pair, with the free ends of the pair of second stop springs facing each other and forming a second passage interval between them. The locking flange forms a first passage interval within the push rod groove. The side wall of the concave straight slot is used as a sawtooth baffle, the first passing interval and the second passing interval are both smaller than the width of the sawtooth baffle, the sawtooth baffle has a first avoiding gap and a second avoiding gap, the free end of the second stop spring enters the concave straight slot through the first avoiding gap and cooperates with the tooth plane, and the lock flange enters the concave straight slot through the second avoiding gap.

8. The injection pen of claim 1, wherein: wherein, The driving entity has a rod part and a seat part which are integrally continuous along the dosing direction, a projection of the seat part along the dosing direction is larger than that of the rod part, and the seat part has a seat hole extending along the dosing direction, the rod part is formed with the push rod accommodating groove, and the push rod accommodating groove is in communication with the seat hole, so that an end part of the dosing push rod is inserted into the seat hole.

9. The injection pen of claim 1, wherein, Further comprising: a pen cover and a cartridge tube, the pen cover is arranged outside the base shell and away from the driving entity, an edge of the pen cover is formed with a locking through hole, and part of the medicine container is located outside the pen cover, the cartridge tube is located on opposite sides of the dosing push rod along the dosing direction, the cartridge tube is hollow and has a locking block inside which cooperates with the locking through hole, and the cartridge tube is arranged outside the medicine container.

10. The injection pen of claim 9, wherein, Further comprising: a pen cap which is arranged outside the cartridge tube and cooperates with the pen cover.

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