Injection pen

Abstract

To provide an injection pen.SOLUTION: An injection pen comprises: a housing; a lead screw axially moveable in the housing; a lead screw cap receiving the lead screw; a dose setting member for correcting a dose; a setback member; a push button operatively connected to the setback member; and a spring member installed toward the push button, where the spring member biases the lead screw in a distal direction.SELECTED DRAWING: Figure 57

Description

Technical Field

[0001] The present invention generally relates to a pen-type medical injection device. More particularly, the present invention relates to a reusable pen-type medical injection device. Even more particularly, the present invention relates to a reusable pen-type medical injection device in which an inaccurate dosage setting can be corrected.

Background Art

[0002] Cross-reference to Related Applications This application claims priority to U.S. Patent Application No. 61 / 861,918, filed Aug. 2, 2013, which is hereby incorporated by reference in its entirety.

[0003] In certain situations, it is desirable to inject a drug directly into human tissue. Typically, a syringe is used to inject a selected dosage of a drug into a patient. A hypodermic syringe has a syringe barrel having a proximal end and a distal end on opposite sides. A cylindrical chamber wall extends between those ends and defines a fluid receiving chamber. The proximal end of the syringe barrel is substantially open and receives a plunger that is slidably and fluid-tightly engaged. The distal end of the syringe barrel has a passageway that communicates with the chamber. A needle cannula can be installed at the distal end of the syringe barrel such that the lumen of the needle cannula communicates with the passageway and chamber of the syringe barrel. Movement of the plunger in the proximal direction draws fluid into the chamber through the lumen of the needle cannula. Movement of the plunger in the direction from the proximal side to the distal side biases fluid to pass through the lumen of the needle cannula from the chamber.

[0004] Drugs administered using conventional subcutaneous syringes are often stored in vials with a pierceable elastomer seal. The drug in the vial is accessed by piercing the elastomer seal with a needle cannula. By moving the plunger proximal a selected distance, a selected dose of the drug can be drawn into the chamber of the syringe barrel. The needle cannula can then be withdrawn from the vial, and the drug can be injected into the patient by moving the plunger distally.

[0005] Some medications, such as insulin, are self-administered. Typical diabetic patients require multiple insulin injections per week or per day. The required insulin dosage varies from patient to patient and may even change within a day or from day to day. Each diabetic patient typically establishes a medication plan that suits their individual health condition and lifestyle. These plans usually include some combination of slow-acting or moderate-acting and fast-acting insulin. Each of these medication plans may require diabetic patients to regularly self-administer insulin in public locations such as the workplace or a restaurant. The required handling of standard subcutaneous syringes and vials can be inconvenient and unsightly in such public settings.

[0006] Medication delivery pens have been developed to facilitate the self-administration of drugs. One example of such a medication delivery pen has been described (see, for example, Patent Document 1), which has a vial holder in which a vial of insulin or other drug can be received. There remains a demand for medication delivery pens that allow the user to easily set and modify the dosage before delivery. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] U.S. Patent No. 5,279,585 (Balkwill) [Overview of the Initiative] [Means for solving the problem]

[0008] Exemplary embodiments of the present invention address at least the above-mentioned problems and / or drawbacks and provide at least the advantages described below.

[0009] According to an exemplary embodiment, the injection pen comprises a housing, a lead screw, a dose setting member, a setback member, and a rotatable drive unit. The lead screw is axially movable within the housing. The dose setting member is connected to the housing for setting and modifying the dose. The setback member is operatively connected to the dose setting member. The rotatable drive unit is operatively connected to the setback member and the lead screw. The drive unit is prevented from rotating while setting and modifying the dose, and during injection, the drive unit rotates to move the lead screw axially.

[0010] According to an exemplary embodiment, the injection pen comprises a housing, a lead screw, a dose setting member, a setback member, and a push button. The lead screw is axially movable within the housing. The dose setting member is connected to the housing for setting and modifying the dose and has a first coupling shape feature. The setback member has a second coupling shape feature for engaging with the first coupling shape feature. The push button is operatively connected to the setback member to engage the second coupling shape feature with the first coupling shape feature during injection. The first coupling shape feature is disengaged from the second coupling shape feature while setting and modifying the dose, and the first coupling shape feature is engaged with the second coupling shape feature during injection.

[0011] According to an exemplary embodiment, the injection pen comprises a housing, a lead screw, a dose setting member, a setback member, a clicker, and a rotatable drive unit. The lead screw is axially movable within the housing. The dose setting member is connected to the housing for setting and modifying the dose. The setback member is operably connected to the dose setting member. The clicker is operably coupled to the dose setting member and the setback member. The rotatable drive unit is operably connected to the setback member and the lead screw. The drive unit is prevented from rotating while setting and modifying the dose, and during injection, the drive unit rotates to move the lead screw axially.

[0012] From the following detailed description, which discloses exemplary embodiments of the present invention in conjunction with the accompanying drawings, additional objectives, advantages and notable features of exemplary embodiments of the present invention will become apparent to those skilled in the art. [Brief explanation of the drawing]

[0013] By reading the following detailed description of a specific exemplary embodiment of the present invention in conjunction with the attached drawings, the above and other exemplary features and advantages of the specific exemplary embodiment of the present invention will become clearer.

[0014] [Figure 1] This is a perspective view showing a medical injection pen according to an exemplary embodiment of the present invention. [Figure 2] Figure 1 is a side view showing the injection pen. [Figure 3] Figure 1 is a front view showing the injection pen. [Figure 4] This is a side cross-sectional view showing the injection pen along line 4-4 in Figure 3. [Figure 5] This is a perspective view showing the syringe pen in Figure 1 with the cap removed. [Figure 6] Figure 5 is a side cross-sectional view showing an injection pen. [Figure 7] Figure 1 shows a disassembled assembly of the injection pen. [Figure 8]Perspective view showing the cartridge holder of the injection pen of FIG. 7. [Figure 9] Side view showing the cartridge holder of FIG. 8. [Figure 10] Side sectional view taken along line 10-10 of FIG. 9. [Figure 11] Elevational cross-sectional view showing the cartridge of the injection pen of FIG. 7. [Figure 12] Perspective view showing the body of the injection pen of FIG. 7. [Figure 13] Top view showing the body of FIG. 12. [Figure 14] Side view showing the body of FIG. 12. [Figure 15] Front view showing the body of FIG. 12. [Figure 16] Side sectional view showing the body of FIG. 13. [Figure 17] Perspective view showing the proximal end of the dose setting member of the injection pen of FIG. 7. [Figure 18] Perspective view showing the distal end of the dose setting member of FIG. 17. [Figure 19] Elevational view showing the dose setting member of FIG. 17. [Figure 20] Elevational cross-sectional view taken along line 20-20 of the dose setting member of FIG. 19. [Figure 21] Perspective view showing the distal end of the setback member of the injection pen of FIG. 7. [Figure 22] Perspective view showing the proximal end of the setback member of FIG. 21. [Figure 23] Elevational view showing the setback member of FIG. 21. [Figure 24] Elevational cross-sectional view showing the setback member taken along line 24-24 of FIG. 23. [Figure 25] Perspective view showing the drive unit of the injection pen of FIG. 7. [Figure 26] Front view showing the drive unit of FIG. 25. [Figure 27] Side sectional view showing the drive unit taken along line 27-27 of FIG. 26. [Figure 28]This is a plan cross-sectional view showing the drive unit along line 28-28 in Figure 26. [Figure 29] Figure 7 is a perspective view showing the distal end of the lead screw of the injection pen. [Figure 30] Figure 29 is a perspective view showing the proximal end of the lead screw. [Figure 31] Figure 7 is a perspective view showing the distal end of the retract nut of the injection pen. [Figure 32] Figure 31 is a perspective view showing the proximal end of the pull-in nut. [Figure 33] Figure 31 is a top view showing the pull-in nut. [Figure 34] Figure 31 is a side view showing the pull-in nut. [Figure 35] Figure 31 is a rear cross-sectional view showing the pull-in nut. [Figure 36] This is a side cross-sectional view showing the pull-in nut along line 36-36 in Figure 35. [Figure 37] Figure 31 is a front cross-sectional view showing the pull-in nut. [Figure 38] Figure 37 is a side cross-sectional view showing the pull-in nut along lines 38-38. [Figure 39] Figure 7 is a perspective view showing the proximal end of the clicker body of the injection pen. [Figure 40] Figure 39 is a perspective view showing the distal end of the clicker body. [Figure 41] Figure 39 is a bottom view showing the clicker body. [Figure 42] Figure 39 is a top view showing the clicker body. [Figure 43] Figure 39 is a side view showing the clicker body. [Figure 44] Figure 7 is a perspective view showing the proximal end of the pilot cap of the injection pen. [Figure 45] Figure 44 is a perspective view showing the distal end of the pilot cap. [Figure 46] Figure 44 is a side view showing the pilot cap. [Figure 47]This is a side cross-sectional view showing the pilot cap along line 47-47 in Figure 46. [Figure 48] Figure 7 is a perspective view showing the spinner of an injection pen. [Figure 49] Figure 48 is a front view showing the spinner. [Figure 50] This is a side cross-sectional view showing the spinner along line 50-50 in Figure 49. [Figure 51] Figure 7 is a perspective view showing the spring cap of the injection pen. [Figure 52] This is a side view showing the spring cap in Figure 51. [Figure 53] This is a side cross-sectional view showing the spring cap along line 53-53 in Figure 52. [Figure 54] Figure 7 is a perspective view showing the proximal end of the button on the injection pen. [Figure 55] Figure 54 is a perspective view showing the distal end of the button. [Figure 56] This is a rear view showing the buttons in Figure 54. [Figure 57] This is a perspective view of the injection pen shown in Figure 1, with the dosage setting component in the state after the dosage has been set. [Modes for carrying out the invention]

[0015] Throughout the drawings, similar reference numerals should be understood to indicate similar elements, features, and structures.

[0016] The examples provided herein are intended to aid in a full understanding of the exemplary embodiments of the present invention, with reference to the drawings in the accompanying documents. Those skilled in the art will therefore recognize that various modifications and alterations of the exemplary embodiments described herein can be made without departing from the scope and spirit of the claimed invention. Furthermore, well-known descriptions of functions and structures are omitted for clarity and brevity.

[0017] A medical injection pen 1 according to an exemplary embodiment is shown in Figures 1 to 7. The injection pen 1 has an upper pen body 2 or housing 2 that houses a plurality of dosage setting components and injection components. The upper pen body 2 is connected to a vial retainer or cartridge holder 3 that houses a drug cartridge 4, as shown in Figures 4 and 6. The injection pen 1 may also have a lower pen cap 5 that covers the cartridge 4 and cartridge holder 3 when the injection pen 1 is not in use. A conventional pen needle 151 may be connected to the threaded portion 11 of the cartridge holder 3. To prevent the needle from accidentally piercing when removing the lower pen cap 5, an outer shield 152 may cover the needle of the attached pen needle.

[0018] The injection pen 1 has a dosage setting member 6 having a knob portion 37 that is rotated by the user to set the desired dosage. The dosage setting member 6 also has a number corresponding to the number of dosing units, which is visible through a window 7 and lens 8 provided in the upper body 2 of the pen. The user rotates the dosage setting member 6 until the desired dosage is visible in the lens 8. The lower body 2 of the pen may have an arrow or other indicator 9 to indicate the set dosage precisely. Once the desired dosage is set, the user presses button 10 until the set amount of medication is completely injected.

[0019] Figures 4 and 6 show cross-sections of the injection pen 1 according to an exemplary embodiment of the present invention. Referencing the individual components can be better understood by considering the exploded assembly diagram shown in Figure 7. As shown, the push button 10 is located at the proximal end, which is closest to the user and furthest from the pen needle 151 connected to the cartridge holder 3. The push button 10 has an annular bead or rim 12, which engages with a corresponding annular groove 13 provided on the inner surface 14 of the dosage setting member 6. In the exemplary embodiment, the connection between the annular rim 12 and the groove 13 is a friction fit that, under the force of a spring member 15, maintains the push button 10 in a biased position on the dosage setting member 6, allowing the push button 10 to be pushed into the dosage setting member 6 when injecting a set dose. The interior of the push button 10 receives the clicker body 16, which rests on the inner surface at the proximal end of the setback member 17. The push button 10 is designed to rotate freely on the clicker body 16.

[0020] According to the exemplary embodiment, the cartridge holder 3 is a substantially hollow member having an open first end 18 and an open second end 19, as best shown in Figures 8 to 10. The cartridge 4 is inserted through an opening at the first end 18 of the cartridge holder 3. A threaded portion 11 extends from the second end 19 toward the first end 18 of the cartridge holder 3 to receive a standard pen needle 151. A window 20 is positioned inside the cartridge holder 3, making the cartridge 4 visible through it and allowing the user to visually inspect the amount of drug in the cartridge 4. A tab 21 is formed on the inner surface 22 of the cartridge holder 3, as shown in Figure 10, and spaced inward from the first end 18. The tab 21 is fitted to engage with a corresponding groove 30 on the body 2. A projection 23 extends axially along the inner surface 22 of the cartridge holder at the first end 18.

[0021] According to the exemplary embodiment, the cartridge 4 has an internal cavity 43 for storing the drug between a stopper 44 and a partition 45, as best shown in Figures 7 and 11. The stopper 44 and partition 45 seal the cartridge 4. The stopper 44 is axially movable within the cavity for drug administration. A standard pen needle 151 penetrates the partition 45 when connected to the cartridge holder 3, thereby creating a flow path out of the cartridge 4 when the lead screw 75 moves the stopper 44 through the cartridge 4.

[0022] According to the exemplary embodiments shown in Figures 12 to 16, the upper body 2 is a generally tubular member having a first end 24 and a second end 25. A first portion 26 of the upper body 2 extends from the first end 24 toward the second end 25. A second portion 27 of the upper body 2 extends from the second end 25 toward the first end 24. A shoulder 28 is formed at the intersection of the first portion 26 and the second portion 27. A window 7 is positioned within the first portion 26 of the upper body 2, thereby making the outer surface 29 of the dosage setting member 6 visible through it. In various exemplary embodiments, an indicator 9 is positioned on one side of the window to facilitate the viewing of the dosage setting value on the outer surface 29 of the dosage setting member 6.

[0023] The second portion 27 of the upper body 2 has a groove 30 having an opening adjacent to the second end 25. The groove 30 receives the tab 21 of the cartridge holder 3, thereby forming a bayonet-type connection for securing the cartridge holder to the upper body 2. In various exemplary embodiments, the groove 30 is substantially L-shaped, comprising a first leg adjacent to the opening for receiving the tab 21 of the cartridge holder, and a second leg substantially perpendicular to the first leg for abutting against or holding the tab 21 of the cartridge holder. In certain embodiments, a substantially similar second groove 46 is located radially opposite to the groove 30, thereby facilitating the securing of the cartridge holder 3 to the upper body 2. Alternatively, instead of the groove 30, threads may be formed at the second end 25 of the second portion 27 of the upper body 2, thereby allowing the cartridge holder 3 to be received in a screw-in manner.

[0024] A pair of ratchet arms 31 and 32 are formed within a second portion 27 of the upper body 2. The ratchet arms 31 and 32 engage with a retractable nut 33 located within the body 2 of the assembled injection pen 1. Ratchet teeth 47 and 48 extend inward from the ratchet arms 31 and 32, respectively. As shown in Figure 16, an opening 49 is formed inside the upper body 2. Multiple teeth 50 extend radially inward from the opening 49. Threads 51 extend along the inner surface 52 of the body from the first end 24 to the second end 25. The opening 49 and the inwardly extending teeth 50 are positioned between the threads 51 and the ratchet arms 31 and 32.

[0025] According to the exemplary embodiments shown in Figures 17 to 20, the dosage setting member 6 is a generally tubular member having a first end 34 and a second end 35. A thread 36 extends along the outer surface 29 from the second end 35 toward the first end 34 and is received by a female thread 51 of the upper body 2. A knob portion 37 is positioned at the first end 34. In various exemplary embodiments, the outer surface of the knob portion 37 has a gripping shape feature, such as a raised line, to facilitate operation of the dosage setting member 6. The dosage setting member 6 has its annular shoulder or rim 38 on the inner surface 14 near the first end 34. The annular shoulder 38 engages with the enlarged portion or head 39 of the setback member 17, as shown in Figures 4 and 6. The annular shoulder 38 of the dosage setting member 6 comprises a first coupling morphological feature, such as a series of teeth or ridges 40, and a second coupling morphological feature, such as one or more teeth or ridges 41 of a similar shape, provided on the enlarged head 39 of the setback member 17. The teeth 40 extend longitudinally toward the first end 34 of the dosage setting member 6, as shown in Figure 20. Multiple ridges or teeth 147 extending radially on the inner surface 14 of the knob-shaped portion 37 are positioned between the annular shoulder 38 and the first end 34.

[0026] According to the exemplary embodiment best shown in Figures 21 to 24, the setback member 17 is a generally tubular member having a first end 53 and a second end 54. The first end 53 has an enlarged head 39 extending radially outward. A plurality of internal teeth or ridges 55 extend radially inward from the inner surface 56 of the enlarged head 39. As shown in Figure 24, an internal shoulder 57 is formed inside the internal teeth 55. One or more teeth 41 extend axially from the surface 42 of the enlarged head 39 of the setback member 17. The second end 54 has a plurality of tabs 58 extending radially inward, positioned on the inner surface 59. According to the exemplary embodiment depicted in Figure 22, the setback member 17 has four equally spaced tabs 58, but any appropriate number of tabs 58 may be used.

[0027] According to the exemplary embodiment shown in Figures 25 to 28, the drive unit 60 has a generally tubular member having a first end 61 and a second end 62. A first arm 63 and a second arm 64 extend axially outward from the second end 62 of the drive unit 60. Tabs 73 and 74 extend radially outward from the free ends of the arms 63 and 64. A first ratchet arm 65 and a second ratchet arm 66 extend circumferentially from the first arm 63 and the second arm 64. Hooks 71 and 72 extend radially outward from the free ends of the ratchet arms 65 and 66, respectively. A groove or slot 67 extends axially rearward within the outer surface 68 of the drive unit 60 toward the first end 61. In the exemplary embodiment, the groove 67 does not extend completely to the inner surface 69 of the drive unit 60, as shown in Figure 28. Since the groove 67 receives the tab 58 of the setback member 17, there will be an equal number of grooves 67 and tabs 58. As shown in Figures 27 and 28, the threaded portion 70 is located at the second end 62 on the inner surface 69 of the drive unit 60.

[0028] The lead screw 75 has a first end 76 and a second end 77, as shown in Figures 29 and 30. Incomplete threaded portions 78 and 79 are located on opposing flat sides 80 and 81. A flange 82 is connected to the first end 76 of the lead screw 76 and has a flat surface 83 from which a first projection 84 extends axially outward. A second projection 85 extends axially outward from the second end 77 of the lead screw 75. A groove 86 is located within the projection 85.

[0029] According to the exemplary embodiment, the pen 1 utilizes a retractable nut 33 having a first end 87 and a second end 88, as shown in Figures 7 and 31-38. An annular flange 89 extends outward from the outer surface 90 of the retractable nut 33 at a first location, and a plurality of ridges or teeth 91 extend outward from the outer surface 90 at a second location. A first opening 92 and a second opening 93 are located within the flange 89, as shown in Figures 31 and 37. Inclined surfaces 94, 95 are located behind the openings 92, 93 to receive a corrugated spring 96. A cavity 97 extends inward from the second end 88 to receive a spinner 98.

[0030] As best shown in Figures 39 to 43, according to an exemplary embodiment, the clicker body 16 has a lower ring 104, an upper ring 105, and an opening 99. The upper ring 105 has a larger outer diameter than the lower ring 104. The clicker body 16 is initially placed inside the dosage setting member 6, and the opening 99 receives the projection 101 of the push button 10. The lower ring 104 has a pair of lower flexible arms 102, 103, and the upper ring 105 has a pair of upper flexible arms 107, 108. The lower surface 106 of the upper ring 105 engages with the first end 53 of the setback member 17, as shown in Figures 4 and 6. The upper hooks 109 and 110 are positioned at the free ends of the upper flexible arms 107 and 108, and the lower hooks 111 and 112 are positioned at the free ends of the lower flexible arms 102 and 103. In the exemplary embodiment, the upper hooks 109 and 110 and the lower hooks 111 and 112 are projections having angled or inclined surfaces, but other suitable sizes, shapes, and configurations may be used. The upper hooks 109 and 110 engage with the teeth 40 of the dosage setting member 6 as shown in Figures 4 and 6. The lower hooks 111 and 112 engage with the teeth 55 of the setback member 17.

[0031] According to the exemplary embodiment, the lead screw cap or co-pilot 113 receives the first projection 84 of the lead screw 75, as best shown in Figures 44 to 47. A flange 114 is positioned at the end 115 of the co-pilot 113 and has an opening 116 therein for receiving the first projection 84 of the lead screw 75. The upper surface 117 of the flange 114 receives the second end 119 of the spring member 15.

[0032] Figures 48 to 50 illustrate an exemplary spinner 98 received by a second projection 85 of the lead screw 75. In various exemplary embodiments, the spinner 98 has an opening 120 extending from a first surface 121 to a second surface 122. A rib 123 extends axially outward from the inner surface 124 of the opening and is received by a groove 86 in the second projection 85 of the lead screw 75. The outer end of the opening 120 is preferably rounded, as shown in Figure 50, thereby facilitating the connection of the spinner 98 to the second projection 85 of the lead screw 75. The engagement between the rib 123 and the groove 86 substantially prevents the spinner 98 from moving axially relative to the lead screw 75, and also allows the spinner 98 to rotate relative to the lead screw 75.

[0033] As shown in Figures 4 and 6, the spring cap 125 is received within the setback member 17. According to the exemplary embodiment, the spring cap 125 has a base member 126 having an inner surface 127 that engages with a first end 118 of a spring member 15. The wall 128 extends axially from the outer edge of the base member 126 and has an opening 129 therein for receiving the spring member 15. In the exemplary embodiment, the spring member 15 is a helical spring. The first end 118 of the spring member 15 engages with the inner surface 127 of the base member 126 of the spring cap 125. The second end 119 engages with the upper surface 117 of the flange 114 of the copilot 113. The spring member 15 biases the lead screw 75 and spring 98 distally, thereby facilitating contact between the lead screw and spinner and the cartridge stopper 44. By maintaining the pressure of the lead screw 75 against the stopper 44, the lead screw 75 does not move axially until it contacts the stopper 44, thereby enabling accurate administration of the set dose.

[0034] The corrugated spring 96 has a first leg 132 and a second leg 133 extending outward from there, as shown in Figure 7. The annular body of the corrugated spring 96 is substantially corrugated. Hooks 134 and 135, such as inclined projections, extend inward from the free ends of the legs 132 and 133. The corrugated spring 96 abuts against the inner shoulder 136 of the body 2. The hooks 134 and 135 of the legs 132 and 133 of the corrugated spring 96 engage with the inclined surfaces 94 and 95 of the retraction nut 33.

[0035] According to the exemplary embodiment, the push button 10 has a base member 28 having an inner surface 129, as best shown in Figures 54 to 56, from which a projection 101 extends axially. A wall 130 extends axially from the outer edge of the base member 128. An annular rim 12 is positioned at the free end of the wall 130. The projection 101 is received by an opening 99 in the clicker body 16. During injection, the lower surface 131 of the annular rim 12 engages with the upper surface 132 of the upper ring 105, thereby increasing the contact surface area between the push button 10 and the clicker body 16.

[0036] Operation and assembly The injection pen 1 has a cap 5 that is removably attached to the cartridge holder 3 to cover the cartridge holder when the pen is not in use. The pen needle 151 is connected to the threaded portion 11 of the cartridge holder. The pen needle has a needle with a first end that penetrates the partition 45 of the cartridge 4, which is placed inside the cartridge holder 3 for the purpose of creating a flow path for the drug stored in the cartridge. The cap 5 covers the needle of the pen needle to substantially prevent accidental puncture.

[0037] The hooks 134 and 135 of the legs 132 and 133 of the corrugated spring 96 engage with the inclined surfaces 94 and 95 of the retraction nut 33. The retraction nut 33 is inserted into the second end 25 of the upper body 2, so that the flange 89 is supported by the flexible ratchet arms 31 and 32. The flange 89 engages the ratchet arms 31 and 32 to substantially prevent the retraction nut 33 from moving distally in the axial direction outward from the upper body 2. The corrugated spring 96 is positioned between the flange 89 of the retraction nut 33 and the shoulder 28 of the upper body 2. The spinner 98 slides on the second projection 85 of the lead screw 75, so that the rib 123 of the spinner engages with the groove 86 in the second projection 85, thereby substantially preventing the spinner 98 from moving axially in any direction relative to the lead screw 75. The spinner 98 can move rotationally with respect to the lead screw 75. The second end 77 of the lead screw 75 is passed through the retraction nut 33, so that the flat sides 80, 81 are aligned with the flat sides 137, 138 of the opening 139 inside. The opening 139 of the retraction nut substantially prevents the lead screw 75 from rotating with respect to the retraction nut 33, while allowing the lead screw to move in both axial directions with respect to the retraction nut. When the spinner 98 contacts the inner shoulder 140 of the retraction nut, the lead screw 75 is prevented from moving in the proximal axial direction, which corresponds to the first or initial position of the lead screw when a new cartridge 4 is inserted into the cartridge holder 3.

[0038] The second end 35 of the dosage setting member 6 is inserted into the first end 24 of the upper body 2, and as a result, the male thread 36 of the dosage setting member 6 engages with the female thread 51 of the body 2 in a screw-in manner. This screw-in connection restricts the rotational movement of the dosage setting member 6 relative to the body. When the dosage setting member 6 is fully inserted into the body 2, the outer shoulder 141 of the dosage setting member 6 contacts the first end 24 of the body 2.

[0039] The drive unit 60 is inserted into the setback member 17, so that the internal tab 58 of the setback member 17 is received by the groove 67 of the drive unit 60, thereby locking the drive unit 60 in the rotational direction relative to the setback member 17. Next, the second end 62 of the drive unit 60 is inserted into the first end 24 of the body 2, so that the female thread 70 of the drive unit 60 engages with the threads 78 and 79 of the lead screw 75. The drive unit 60 is then rotated, thereby moving it axially along the lead screw 75 until the legs 63 and 64 pass through the opening 136 in the body 2. The hooks 73 and 74 of the legs 63 and 64 engage with the internal shoulder 136 of the body 2, thereby substantially preventing the drive unit 60 from moving proximal in the axial direction relative to the body 2. The inner surface 56 of the enlarged head 39 of the setback member 17 contacts the inner shoulder 38 of the dosage setting member 6, thereby restricting the setback member 17 from moving distally in the axial direction.

[0040] The copilot 113 is positioned on the first projection 84 of the lead screw 75, and the second end 119 of the spring member 15 engages with the upper surface 117 of the flange 114 of the copilot 113. Then, the inner surface 127 of the spring cap 125 engages with the first end 118 of the spring member 15.

[0041] The protruding portion 101 of the push button is inserted into the opening 99 of the clicker body. Next, the clicker body 16 is inserted into the first end portion 34 of the dosage setting member 6, so that the annular rim 12 of the push button 10 is received by the annular groove 13 in the dosage setting member 6.

[0042] The cartridge holder 3 is connected to the body 2, and as a result, the internal tab 21 of the cartridge holder 3 is received by a groove 30 at the second end 25 of the body 2, thereby securing the cartridge holder 3 to the body 2. When the cartridge holder is connected to the body 2, the internal projection 23 of the cartridge holder 3 contacts the ratchet arms 31 and 32 of the body 2, bending them inward. The ratchet teeth 47 and 48 of the ratchet arms 31 and 32 engage with the teeth 91 of the retraction nut. Thus, when the cartridge holder 3 is connected to the body 2 of the injection pen 1, rotational movement of the retraction nut 33 is substantially prevented.

[0043] As shown in Figures 25, 27, and 28, grooves 142 are formed in arms 63 and 64 of the drive unit 60, which are received by an inner wall 143 forming an opening 49 within the upper body 2, thereby allowing the drive unit 60 to rotate, while still substantially preventing axial movement of the drive unit 60 relative to the body 1. Hooks 71 and 72 of the first ratchet arm 65 and the second ratchet arm 66 of the drive unit 60 engage with teeth 50 extending radially outward from the opening 49 in the body. The teeth 50 substantially prevent the drive unit 60 from rotating (counterclockwise) relative to the body 2 during dose setting, and also allow the drive unit 60 to rotate during injection. During injection, as the hooks pass over the teeth, the hooks 71 and 72 of the ratchet arms 65 and 66 produce an audible sound such as a click, thereby informing the user that an injection is being performed.

[0044] The flat sides 137 and 138 of the opening 139 of the retraction nut are connected to the flat sides 80 and 81 of the lead screw 75, thereby substantially preventing the lead screw 75 from rotating relative to the retraction nut 33. Therefore, when the cartridge holder 3 is not connected to the upper body 2, the retraction nut 33 and the lead screw 75 can rotate freely. This allows the lead screw 75 to be driven backward while rotating into the body 2 against the force of the spring member 15 when the user inserts a new cartridge 4. The spinner 98 of the lead screw, which is attached to the lead screw 75, can rotate freely on the lead screw 75 relative to the cartridge stopper 44. The spinner 98 increases the contact surface area of ​​the lead screw 75 with respect to the stopper 44, thereby facilitating the movement of the stopper so that the cartridge 4 passes through by the lead screw 75 during injection.

[0045] When the cartridge holder 3 locks the retraction nut 33 in the rotational direction within the body 2, the engagement between the flat sides 137 and 138 of the opening 139 of the retraction nut and the flat sides 80 and 81 of the lead screw 75 substantially prevents the lead screw 75 from rotating. The internally threaded portion 70 of the drive unit 60 engages with the threaded sides 78 and 79 of the lead screw 75, thereby driving the lead screw distally during injection, so as to move toward and in contact with the cartridge stopper 44 in the cartridge 4. Therefore, during injection, the lead screw 75 does not move in the rotational direction, but only axially with respect to both the body 2 and the retraction nut 33.

[0046] The setback member 17 has a plurality of internal tabs 58 that move within corresponding grooves 67 in the drive unit 60. When the thumb button 10 is pressed during injection, the axially extending teeth 41 of the setback member 17 engage with the internal teeth 40 on the inner shoulder 38 of the dose setting member 6, locking the internal teeth 40.

[0047] A screw thread 51 for dose setting on the inner surface 52 of body 2 is connected to a male thread 36 of dose setting member 6, thereby allowing the dose setting member 6 to rotate out of body 2 during dose setting and to rotate back into body during injection, as shown in Figure 57. The dose setting value on the outer surface 29 of dose setting member 6 is visible through lens 8. An indicator 9 adjacent to lens 8 facilitates the appropriate setting of the desired dose.

[0048] The thumb button 10 is fitted into the first end 34 of the dosage setting member 6, allowing the button 10 to rotate relative to the dosage setting member 6 during injection. The button 10 also holds the clicker body 16 engaged with the dosage setting member 6 and the setback member 17. The upper arms 107, 108 of the clicker body 16 engage with radially extending teeth 147 on the inner surface 14 of the dosage setting member 6, thereby substantially preventing relative rotation between the dosage setting member 6 and the clicker body 16 during dial-back, but allowing relative rotation in a counterclockwise direction during dosage setting. Thus, by moving the dosage setting member 6 relative to the clicker body 16 when setting the dosage, an audible and / or tactile indication, such as a click sound, is created. The lower arms 102 and 103 of the clicker body 16 engage with radially extending teeth 55 on the inner surface 59 of the setback member 17, thereby substantially preventing relative rotation between the setback member 17 and the clicker body 16 during dosage setting, but allowing relative clockwise rotation during dial-back. Thus, when correcting the dosage (dial-back), moving the setback member 17 relative to the clicker body 16 creates an audible and / or tactile indication, such as a click.

[0049] The spring cap 125 is held within the setback member 17 on the drive unit 60, and the spring member 15 is held between the spring cap 125 and the upper surface 117 of the flange 114 of the copilot 113. Inwardly extending tabs 145 and 146 (Figures 51-53) engage with the circumferential groove 114 of the drive unit 60 (Figures 25, 27, and 28), thereby substantially preventing the spring cap 125 from moving in the axial proximal direction. The spring member 15 biases the lead screw 75 distally, thereby substantially maintaining the state in which the lead screw 75 is in contact with the cartridge stopper 4, specifically after replacing an old cartridge with a new one. The corrugated spring 96 biases the retraction nut 33 distally, so that the second end 88 of the retraction nut 33 abuts against the end 148 of the cartridge 4, as shown in Figures 4 and 6. The biasing force of the wave spring 96 effectively prevents the cartridge 4 from moving, such as by rattling, when it is placed inside the cartridge holder 3.

[0050] To set the dosage, the user rotates the dosage setting member 6 clockwise until the desired dosage is displayed in the dosage display lens 8 inside the upper body 2. Multiple dosage numbers on the outer surface of the dosage setting member 6 become visible through the lens 8. When the desired dosage is reached, the user presses down the thumb button 10 until the dosage setting member 6 is fully returned to the body 2 to inject the dose.

[0051] During dose setting, as shown in Figure 57, the dose setting member 6 rotates outward away from the first end 24 of the upper body 2. The internal shoulder 38 of the dose setting member 6 contacts the surface 42 of the enlarged head portion 39 of the setback member 17, and the dose setting member 6 is used to pull the setback member 17 in the axial proximal direction. The internal tab 58 of the setback member 17 moves axially within the groove 67 of the drive unit 60, maintaining a fixed state in the rotational and axial directions. The engagement between the tab 58 of the setback member and the groove 67 of the drive unit substantially prevents the setback member 17 from rotating relative to the drive unit 60. Also, during dose setting, the clutch teeth 41 on the enlarged head portion 39 of the setback member 17 slide over the teeth 40 of the dose setting member 6 because there is insufficient axial pressure to lock the setback teeth 41 using the teeth 40 of the dose setting member. As the dosage setting member 6 rotates away from the upper body 2, the pair of upper arms 107 and 108 of the clicker body 16 pass over the teeth 147 of the dosage setting member 6, thereby creating an audible and / or tactile indication. The pair of lower arms 102 and 103 remain locked in place by the teeth 55 of the setback member 17.

[0052] When setting the dosage and when correcting the dosage (dial-back), rotational movement of the setback member 17 is substantially prevented. Consequently, rotational movement of the drive unit 60 is also substantially prevented. Furthermore, since rotation of the drive unit 60 is prevented during dosage setting and correction, axial movement of the lead screw 75 is also substantially prevented.

[0053] If the user exceeds the desired dosage, the dosage setting member 6 can be dialed back, for example, counterclockwise, to the desired correct dosage. The dosage setting member 6 is rotated back into the upper body 2 in the opposite direction to the dosage setting direction, for example, clockwise, until the desired dosage is displayed in the lens 8. The dosage setting member 6 can rotate freely back into the upper body 2 to correct the set dosage without performing any additional steps or functions. During dosage correction, the setback member 17 is locked in place to prevent rotation by the engagement of the tab 58 of the setback member with the groove 67 of the drive unit. The axial pressure acting during dialing back is not large enough to engage the clutch teeth 41 of the setback member 17 with the teeth 40 of the dosage setting member 6. When the dosage setting member 6 rotates back into the body 2, the lower arms 102, 103 of the clicker body 16 pass over the teeth 55 of the setback member 17, thereby providing an audible and / or tactile indication of the dial back. The upper arms 107 and 108 remain locked to the teeth 147 of the dosage setting member 6.

[0054] During injection, the user presses down the thumb button 10 until the dosage setting member 6 rotates and returns completely into the upper body 2. As the dosage setting member 6 rotates and returns into the upper body 2, the clutch teeth 41 of the setback member 17 lock onto the teeth 40 on the dosage setting member 6, causing both the dosage setting member 6 and the setback member 17 to rotate. As the tab 58 of the setback member engages with the groove 67 of the drive unit, the setback member 17 rotates as the setback member moves distally along the drive unit 60, causing the drive unit 60 to rotate. As the drive unit 60 rotates, the female thread 70 of the drive unit 60 drives the lead screw 75 distally, thereby pushing the stopper 44 axially through the cartridge 4 and injecting the drug. The lead screw 75 is keyed to the flat sides 137, 138 of the retraction nut 33 and does not rotate during injection, thus remaining fixed in the rotational direction relative to the upper body 2 while the cartridge holder 3 is connected to the upper body 2. When the drive unit 60 rotates, the hooks 71, 72 of the first ratchet arm 65 and the second ratchet arm 66 of the drive unit 60 pass over teeth 50 that extend radially outward from the body opening 49 of the upper body 2, thereby creating an audible and / or tactile indication during dose injection.

[0055] When replacing a cartridge, the user rotates or removes the cartridge holder 3 from the upper body 2 and removes the old cartridge. The new cartridge is placed inside the cartridge holder 3. When the cartridge holder 3 is reattached to the upper body 2, the cartridge stopper 44 applies pressure to the spinner 98. Since the protrusion 23 of the cartridge holder 3 has not yet engaged with the ratchet arms 31 and 32 of the upper body 2, the ratchet arms 31 and 32 do not prevent the rotation of the retraction nut 33, and therefore the retraction nut 33 can rotate freely. The drive unit 60 is locked to the upper body 2 in the axial and rotational directions. The force applied by the cartridge stopper 44 to the spinner 98 and lead screw 75 rotates the lead screw 75 via the female thread 70 of the drive unit 60. Since the spinner 98 can rotate freely on the lead screw 75, no excessive pressure is applied to the stopper 44. The ratchet arms 31 and 32 of the upper body 2 passing over the teeth 91 of the retraction nut 33 makes an audible and / or tactile indication that the lead screw 75 is being driven backward into the body. When the projection 23 of the cartridge holder engages the ratchet arms 31 and 32 of the body, the ratchet arms 31 and 32 are bent inward to engage the teeth 91 of the retraction nut 33, thereby stopping the rotation of the retraction nut 33. Once the rotation of the retraction nut 33 has stopped, the lead screw 75 is prevented from rotating further by the engagement of the flat sides 137 and 138 of the opening 139 of the retraction nut with the flat sides 80 and 81 of the lead screw 75.

[0056] The above detailed description of specific exemplary embodiments is provided to illustrate the principles of the invention and its practical applications, thereby enabling those skilled in the art to understand the invention in relation to various embodiments with various modifications suitable for specific intended uses. This description is not necessarily intended to be comprehensive or to limit the invention to the exemplary embodiments disclosed. Any of the embodiments and / or elements disclosed herein can be combined with each other to form various additional embodiments not specifically disclosed. Therefore, additional embodiments are possible and are intended to be covered herein and in the appended claims. This specification describes specific examples for achieving more general objectives that may be achieved by other means.

[0057] As used herein, the terms “front,” “rear,” “up,” “down,” “upward,” “downward,” and other directional descriptors are intended to facilitate the description of exemplary embodiments of the present invention and are not intended to limit the structure of the exemplary embodiments of the present invention to any particular position or direction. Those skilled in the art will understand that terms of degree, such as “substantially” or “about,” mean a reasonable range of deviation from given values, such as general tolerances, associated with the manufacture, assembly, and use of the embodiments described.

Claims

1. Housing and A lead screw that is movable in the axial direction within the housing, wherein the lead screw has a first lead screw end and a second lead screw end facing the first lead screw end, and the first lead screw end has a lead screw with a first projection, A lead screw cap that receives the first protrusion of the lead screw, A dosage setting member for setting and modifying a dosage, wherein the dosage setting member is screw-connected to the housing and has a first coupling shape characteristic, A setback member having a second coupling shape feature for engaging with the first coupling shape feature, A push button is operatively connected to the setback member and causes the second coupling shape feature to engage with the first coupling shape feature during injection, A spring member having a first spring member end positioned in the proximal direction toward the push button, and a second spring member end positioned in the distal direction and facing the first spring member end. Equipped with, The end of the second spring member engages with the lead screw cap, thereby causing the spring member to bias the lead screw distally. An injection pen characterized in that, during injection, the second coupling shape feature of the setback member engages with the first coupling shape feature of the dosage setting member, causing the dosage setting member and the setback member to rotate together, thereby moving the lead screw distally along the axial direction.

2. The injection pen according to claim 1, characterized in that the first binding shape feature detaches from the second binding shape feature while setting and modifying the dosage, and engages with the second binding shape feature during injection.

3. The injection pen according to claim 1 or 2, further comprising a clicker that produces an audible or tactile indication when in operation, wherein the clicker is operatively connected to the dosage setting member.

4. The injection pen according to claim 3, characterized in that the push button receives the clicker.

5. The injection pen according to claim 1, 2, 3, or 4, further comprising a rotatable drive unit that is locked in the rotational direction with respect to the setback member.

6. The injection pen according to claim 1, 2, 3, 4, or 5, characterized in that the dosage setting member rotates in a first direction from the housing to set the dosage, and the dosage setting member is freely rotatable in a second direction to modify the dosage.

7. The injection pen according to any one of claims 1 to 6, characterized in that the first coupling shape feature includes a set of first teeth, and the second coupling shape feature includes at least one second tooth.

8. The injection pen according to any one of claims 1 to 7, further comprising a cartridge holder and a retraction nut connected to the housing and receiving the lead screw.

9. The retractable nut further comprises a flat side portion configured to be relative to the housing, The lead screw is axially movable within the housing and engages with the flat side of the retraction nut. The injection pen according to any one of claims 1 to 8, characterized in that the dose setting member comprises an internal shoulder and teeth.

10. The setback member and the dosage setting member are further operably connected to a clicker and a rotatable drive unit, The setback member comprises a tab, an expanding head, and teeth, the expanding head being operatively connected to the internal shoulder of the dosage setting member during dosage setting and modification. The rotatable drive unit is provided with a groove that is operatively connected to the tab, and the rotatable drive unit is operatively connected to the lead screw, During dose setting and adjustment, the rotatable drive unit is prevented from rotating, the teeth of the setback member slide over the teeth of the dose setting member, the clicker arm passes over at least one of the teeth of the setback member and the teeth of the dose setting member, and the setback member is rotatably locked by the engagement of the tab of the setback member and the groove of the rotatable drive unit. The injection pen according to claim 9, characterized in that, during injection, the push button is pressed until the dosage setting member is fully rotated and returned to the housing, the retraction nut is rotatably fixed to the housing to prevent rotation of the lead screw, the teeth of the setback member engage with the teeth of the dosage setting member, thereby rotating the rotatable drive unit, moving the lead screw axially via the engagement of the tab of the setback member with the groove of the driver, and pressing the stopper to administer the drug.

11. The dosage setting member rotates in a first direction away from the housing to set the dosage, rotates in a second direction away from the housing to correct the dosage, and rotates in a second direction away from the housing during injection. The injection pen according to claim 10, characterized in that the setback member moves axially relative to the dose setting member without rotating relative to the housing while setting and correcting the dose, and rotates together with the dose setting member during injection.

12. The injection pen according to claim 10 or 11, characterized in that the setback member is movable in the axial direction relative to the rotatable drive unit.

13. The injection pen according to any one of claims 10 to 12, characterized in that the setback member is coupled with the dose setting member during injection, so that the setback member and the dose setting member are locked in the rotational direction.

14. The injection pen according to any one of claims 10 to 13, characterized in that the force applied to the push button during injection causes the setback member to engage with the dosage setting member.

15. The injection pen according to any one of claims 10 to 14, further comprising a cartridge holder.

16. The injection pen according to claim 15, characterized in that when the cartridge holder is not connected to the housing, the lead screw rotates relative to the retraction nut, and when the cartridge holder is connected to the housing, the lead screw is fixed to the retraction nut in the rotational direction.

17. The injection pen according to any one of claims 1 to 16, wherein the spring member maintains the push button in a biased position on the dosage setting member, allows the push button to be pushed distally into the dosage setting member, and causes engagement of the second coupling shape feature with the first coupling shape feature during injection.

18. The lead screw cap comprises a flange having an opening for receiving the first projection of the lead screw, The injection pen according to any one of claims 1 to 16, characterized in that the upper surface of the flange receives the end of the second spring member of the spring member.

19. The end of the second lead screw has a second projection, and the injection pen further comprises a spinner that receives the second projection of the lead screw. The injection pen according to any one of claims 1 to 16, characterized in that the spring member biases the lead screw and the spinner in the distal direction.

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