Self-controllable load spring washer

Abstract

The present disclosure provides a load spring washer configured for use with a medical injection device, the load spring washer having a body and one or more protrusions, the body having a proximal surface and a distal surface, and the one or more protrusions extending proximally away from the proximal surface of the body.

Description

[0001] Cross - reference to related applications

[0002] This application claims the benefit of U.S. Provisional Patent Application No. 62 / 872,017, filed on Jul. 9, 2019, and U.S. Utility Patent Application No. 16 / 922,137, filed on Jul. 7, 2020, the contents of both of which are hereby incorporated by reference in their entireties. Technical field

[0003] The present disclosure generally relates to spring washers that can be used as alternatives to helical springs for medical devices, and in certain embodiments or aspects, to injection devices that include spring washers, where the spring washers include elastomeric spring washers. Background art

[0004] Medical injection devices typically utilize elastic members (such as springs) placed between various components to bias these components in order to ensure more precise drug delivery. However, the use of current elastic members in medical injection devices has drawbacks, such as lack of control and load recovery. Therefore, there is a need in the art for a more robust member that allows for greater load recovery. Summary of the invention

[0005] Provided herein is a load spring washer configured for use with a medical injection device, the load spring washer having a body with a proximal surface and a distal surface; and one or more protrusions extending proximally away from the proximal surface of the body.

[0006] Also provided herein is a load spring washer configured for use with a medical injection device, the load spring washer having a circular body with a proximal surface and a distal surface, wherein a cross - sectional profile of the body taken along a plane extending between the proximal surface and the distal surface has a sinusoidal shape.

[0007] Also provided herein is a load spring washer configured for use with a medical injection device, the load spring washer having a circular body with a frustoconical shape.

[0008] Also provided herein is a load spring washer configured for use with a medical injection device, the load spring washer having a body including a ring with a proximal surface and a distal surface, the load spring washer including at least one arm and / or at least one flange that protrudes parallel to a longitudinal axis defined by the proximal surface and the distal surface of the body.

[0009] Also provided herein is a medical injection device having a housing; a braking member received within the housing; a barrel received within the housing and holding a composition therein; a load spring washer as described herein, the load spring washer being received within the housing and positioned between the braking member and the housing; an injection needle in fluid communication with the barrel; and an actuating member at a proximal end of the housing, the actuating member being configured to actuate the medical injection device to deliver the composition through the injection needle.

[0010] Further embodiments or aspects are set forth in the following numbered clauses:

[0011] 1. A load spring washer configured for use with a medical injection device, comprising: a body having a proximal surface and a distal surface; and one or more protrusions extending proximally away from the proximal surface of the body.

[0012] 2. The load spring washer according to clause 1, wherein the body is generally circular.

[0013] 3. The load spring washer according to clause 1 or clause 2, wherein the body defines a hole such that the body is annular.

[0014] 4. The load spring washer according to any one of clauses 1 - 3, wherein a cross-sectional profile of the one or more protrusions taken along a plane extending between the proximal surface and the distal surface includes a parallelogram.

[0015] 5. The load spring washer according to any one of clauses 1 - 3, wherein the one or more protrusions are cylindrical.

[0016] 6. The load spring washer according to clause 5, wherein a cross-sectional profile of the one or more protrusions taken along a plane extending between the proximal surface and the distal surface includes a cylinder.

[0017] 7. The load spring washer according to clause 5 or clause 6, wherein the cylinder defines a hollow interior.

[0018] 8. The load spring washer according to clause 7, wherein the hollow interior is filled with gas.

[0019] 9. The load spring washer according to clause 7, wherein the hollow interior includes a vacuum.

[0020] 10. The load spring washer according to any one of clauses 1-3, wherein a cross-sectional profile of the one or more protrusions taken along a plane extending between the proximal surface and the distal surface includes a rhombus.

[0021] 11. The load spring washer according to any one of clauses 1-3, wherein a cross-sectional profile of the one or more protrusions taken along a plane extending between the proximal surface and the distal surface includes an S shape.

[0022] 12. The load spring washer according to any one of clauses 1-3, wherein a cross-sectional profile of the one or more protrusions taken along a plane extending between the proximal surface and the distal surface includes an L shape.

[0023] 13. The load spring washer according to any one of clauses 1-3, wherein the body includes a plurality of rings.

[0024] 14. The load spring washer according to clause 13, wherein the plurality of rings include concentric circles with a gap between each concentric circle.

[0025] 15. The load spring washer according to clause 14, wherein at least one of the concentric circles has a width greater than the width of another of the concentric circles.

[0026] 16. The load spring washer according to any one of clauses 13-15, wherein a cross-sectional profile of the one or more protrusions taken along a plane extending between the proximal surface and the distal surface includes a U shape, wherein the U shape includes: a first arm connected to a first ring of the plurality of rings of the body and a second arm connected to a second ring of the plurality of rings of the body, both the first arm and the second arm extending parallel to a longitudinal axis defined by the proximal surface and the distal surface of the body; and a transverse member connecting the first arm and the second arm and extending perpendicular to the longitudinal axis defined by the proximal surface and the distal surface of the body.

[0027] 17. The load spring washer according to any one of clauses 13-15, wherein the one or more protrusions include an arch, the arch including: a first arm connected to a first ring of the plurality of rings of the body and a second arm connected to a second ring of the plurality of rings of the body, both the first arm and the second arm extending parallel to a longitudinal axis defined by the proximal surface and the distal surface of the body; and a curved portion connecting the first arm and the second arm.

[0028] 18. The load spring washer according to any one of clauses 1-3, wherein the protrusion includes a frustoconical portion.

[0029] 19. A load spring washer according to any one of clauses 1 - 18, wherein the load spring washer comprises an elastomeric material.

[0030] 20. A load spring washer according to any one of clauses 1 - 19, wherein the load spring washer comprises rubber.

[0031] 21. A load spring washer according to any one of clauses 1 - 20, wherein the load spring washer is formed of ethylene propylene diene monomer (EPDM) rubber.

[0032] 22. A load spring washer according to any one of clauses 1 - 21, wherein the Shore A hardness of the load spring washer is 20 - 40, preferably 30 - 40.

[0033] 23. A load spring washer comprising a circular body having a proximal surface and a distal surface, wherein a cross-sectional profile of the body taken along a plane extending between the proximal surface and the distal surface comprises a sine wave shape.

[0034] 24. A load spring washer comprising a circular body having a frustoconical shape.

[0035] 25. A load spring washer comprising a body, the body comprising a ring having a proximal surface and a distal surface, the load spring washer comprising at least one arm and / or at least one flange that projects parallel to a longitudinal axis defined by the proximal surface and the distal surface of the body.

[0036] 26. A load spring washer according to any one of clauses 23 - 25, wherein the load spring washer comprises an elastomeric material.

[0037] 27. A load spring washer according to any one of clauses 23 - 26, wherein the load spring washer comprises rubber.

[0038] 28. A load spring washer according to any one of clauses 23 - 27, wherein the load spring washer is formed of ethylene propylene diene monomer (EPDM) rubber.

[0039] 29. A load spring washer according to any one of clauses 23 - 28, wherein the Shore A hardness of the load spring washer is 20 - 40, preferably 30 - 40.

[0040] 30. A medical injection device, comprising a housing; a braking member received within the housing; a barrel received within the housing and holding a composition therein; a load spring washer according to any one of clauses 1-29, the load spring washer being received within the housing and positioned between the braking member and the housing; an injection needle in fluid communication with the barrel; and an actuating member at a proximal end of the housing, the actuating member being configured to actuate the medical injection device to deliver the composition through the injection needle. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1A - 1C Illustrating various embodiments or aspects of a load spring washer as described herein;

[0042] Figure 2 Schematic illustration of a load spring washer according to one non-limiting embodiment or aspect;

[0043] Figure 3A - 3B Schematic illustration of a load spring washer according to one non-limiting embodiment or aspect, and a force diagram illustrating the deflection of the struts of the load spring washer;

[0044] Figure 4A - 4B Schematic illustration of a load spring washer according to non-limiting embodiments or aspects;

[0045] Figure 5 Schematic illustration of a load spring washer according to one non-limiting embodiment or aspect;

[0046] Figure 6A - 6D Schematic illustration of a load spring washer according to non-limiting embodiments or aspects;

[0047] Figure 7A - 7C Schematic illustration of a load spring washer according to non-limiting embodiments or aspects;

[0048] Figure 8A - 8D Schematic illustration of a load spring washer according to non-limiting embodiments or aspects;

[0049] Figure 9A - 9B Schematic illustration of a load spring washer according to non-limiting embodiments or aspects;

[0050] Figure 10A - 10B Schematic illustration of a load spring washer according to non-limiting embodiments or aspects;

[0051] Figure 11A - 11E Illustrating various embodiments or aspects of a load spring washer as described herein;

[0052] Figure 12A - 12BIllustrate a load spring washer according to a non - restrictive embodiment or aspect and the placement of the load spring washer within the housing of a drug delivery device;

[0053] Figure 13A - 13B Illustrate a load spring washer according to a non - restrictive embodiment or aspect and the placement of the load spring washer within the housing of a drug delivery device;

[0054] Figure 14A - 14B Illustrate a load spring washer according to a non - restrictive embodiment or aspect and the placement of the load spring washer within the housing of a drug delivery device;

[0055] Figure 15A - 15B Illustrate a load spring washer according to a non - restrictive embodiment or aspect and the placement of the load spring washer within the housing of a drug delivery device;

[0056] Figure 16 Is an exploded view of a medical injection device comprising a load spring washer as described herein;

[0057] Figure 17 Is a graph showing the relationship between load and extension amount of a non - restrictive embodiment or aspect of the load spring washer described herein;

[0058] Figure 18A - 18B Is a schematic diagram of a load spring washer according to a non - restrictive embodiment or aspect; and

[0059] Figure 19A - 19B Is a schematic diagram of a load spring washer according to a non - restrictive embodiment or aspect. Detailed Description

[0060] Unless otherwise expressly stated, the use of numerical values within the various ranges specified in this application is presented as an approximation, as if the minimum and maximum values within the specified ranges both began with the word "about". As used herein, the term "about" means the specified value ± 10%. In this way, minor variations above and below the specified range can be used to obtain substantially the same results as the values within the range. Additionally, unless otherwise stated, the disclosure of these ranges is intended as a continuous range encompassing every value between the minimum and maximum values. For the definitions provided herein, these definitions refer to the lexicographical form, cognates, and grammatical variants of these words or phrases.

[0061] Unless otherwise specified, the drawings of the present application are representative in nature and should not be construed as implying any specific scale or directionality. For the purposes of the description hereinafter, the terms "upper", "lower", "right", "left", "vertical", "horizontal", "top", "bottom", "lateral", "longitudinal" and their derivatives shall relate to the present invention when the present invention has the orientation in the drawings. However, it should be understood that, unless explicitly stated to the contrary, the present invention may assume various alternative variations and sequences of steps. Accordingly, the specific dimensions and other physical characteristics related to the embodiments disclosed herein should not be considered restrictive.

[0062] Provided herein is a load spring washer that serves as an alternative to a spring in a medical device. As is known to those skilled in the art, a spring washer is a washer having axial flexibility. As used herein, the "spring" aspect of a spring washer for a medical device is a washer that has axial flexibility due to the material forming the washer (e.g., compressibility / expandability resulting from the elastomeric properties of the material), the shape or form of the washer, and combinations thereof. In non-limiting embodiments or aspects, the load spring washer is formed of an elastomeric material. In non-limiting embodiments or aspects, the elastomeric material is a highly elastic elastomeric material. In non-limiting embodiments or aspects, the load spring washer is formed of rubber. In non-limiting embodiments or aspects, the rubber is polyisoprene rubber, silicone rubber, and / or butyl rubber. In non-limiting embodiments or aspects, the rubber is butyl rubber (IIR), isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene rubber (SBR), ethylene-propylene rubber (EPM), ethylene-propylene-diene rubber (EPDM), chlorosulfonated polyethylene (CSM), ethylene-vinyl acetate copolymer (EVA), styrene-isoprene rubber (SIR), thermoplastic elastomer, and / or natural rubber.

[0063] In non-limiting embodiments or aspects, the load spring washer is formed of an elastomeric copolymer, including but not limited to thermoplastic elastomers, thermoplastic vulcanizates, styrene copolymers such as styrene-butadiene (SBR or SBS) copolymers, styrene-isoprene (SIS) block polymers or styrene-isoprene / butadiene (SIBS), wherein the content of styrene in the styrene block copolymer is from about 10% to about 70%, preferably from about 20% to about 50%. The elastomeric composition may include but not be limited to: antioxidants and / or inorganic reinforcing agents to maintain the stability of the elastomeric composition; vulcanizing agents, vulcanization accelerators, vulcanization activators, processing aids, fillers, etc. to maintain and improve the physical properties and heat resistance of the rubber material.

[0064] In non-limiting embodiments or aspects, the load spring washer is formed from a material having a Shore A hardness value of 20 - 40, optionally 30 - 40 (all values and sub-ranges therebetween are included). In non-limiting embodiments or aspects, the load spring washer is formed from a material including ethylene propylene diene monomer (EPDM) rubber. In non-limiting embodiments or aspects, the load spring washer is formed from a material including EPDM rubber and various fillers / additives. In non-limiting embodiments or aspects, the load spring washer is formed from ultra-high molecular weight EPDM rubber (e.g., KELTAN 9565Q), various fillers (e.g., MISTRON steam), mineral oil, zinc oxide, stearic acid, antioxidant(s) (e.g., SONGNOX 1076), cure accelerator(s) (e.g., TBzTD), vulcanizing agent(s) (e.g., VULTAC 710), and sulfur (such as wettable sulfur).

[0065] In non-limiting embodiments or aspects, the load spring washer is formed from foam. In non-limiting embodiments or aspects, the load spring washer is formed from a mixture of materials, such as but not limited to metal and / or polymer, and rubber and / or foam. For example, but not limited to, the load spring washer described below may include a body and protrusions, the body being metal, polymer, or a mixture, and the protrusions being formed from an elastomeric material such as rubber, foam, or an elastomeric polymer.

[0066] Turning to Figure 1A - 1C , various load spring washers 100 as described herein are shown. Figure 1A - 1C The load spring washer shown in is generally circular; however, those of ordinary skill in the art will understand that any suitable shape may be used depending on the intended use / application. Figure 11A - 11E Various non-limiting embodiments or aspects of shapes that can be used for the load spring washer 100 as described herein are shown, including circular, annular, star-shaped, and h-shaped. It should be understood that the illustrated shapes are merely exemplary and the present disclosure is not limited thereto.

[0067] Turning to Figure 2 , a schematic view of a load spring washer 100 according to non-limiting embodiments or aspects is shown. In non-limiting embodiments or aspects, the load spring washer 100 may include a body 105 and one or more protrusions 110 extending from the body 105, such as struts. The body includes a proximal surface 101 and a distal surface 102, the proximal surface and the distal surface defining a longitudinal axis therebetween. Without being bound by theory, the applicant believes that the struts 110 allow the compression force of the load spring washer to be modified by providing resistance to compression. Although Figure 2(And other figures) show a specific number of protrusions, such as struts, but it should be understood that the number of protrusions 110 such as struts can be modified to provide an appropriate modification to the compressive force for the intended application. The protrusions 110 can assume any useful shape and orientation on the load spring washer body 105. Those skilled in the art will understand that the thickness (depth) and peripheral dimensions (width) of the body 105 can be adjusted as long as the load spring washer exhibits the flexure or buckling characteristics described herein when a force or pressure is applied parallel to the longitudinal axis defined by the proximal surface 101 and the distal surface 102 of the body 105.

[0068] Go to Figure 3A , showing a schematic view of a load spring washer 100 according to a non-limiting embodiment or aspect. The load spring washer 100 includes a body 105 and one or more S-shaped protrusions 110, wherein the gap 120 between the proximal (uppermost) portion of the S-shaped protrusion and the body 105 has a predetermined height. The design of the protrusions 110 in Figure 3 allows the protrusions to flex or buckle into a flat orientation when a force is applied in a direction perpendicular to the body 105, as Figure 3B shown, such that the height of the gap 120 is less than the height when no force is applied to the load spring washer 100. As described above, the protrusions (here, S-shaped protrusions), including their respective parts, can have any suitable dimensions, and the gap 120 can similarly have any suitable dimensions.

[0069] Go to Figure 4A - 4B , showing a schematic view of a load spring washer 100 according to a non-limiting embodiment or aspect. The load spring washer 100 includes a body 105 and one or more L-shaped protrusions 110, wherein there is a gap 120 between the proximal (uppermost) portion of the L-shaped protrusion 110 and the body 105. As described above, the protrusions (here, L-shaped protrusions), including their respective parts, can have any suitable dimensions, and the gap 120 can similarly have any suitable dimensions.

[0070] Go to Figure 5, a schematic diagram showing a load spring washer 100 according to a non - restrictive embodiment or aspect. The load spring washer 100 includes a multi - piece body, and the multi - piece body includes an inner portion 107 and an outer portion 109. In a non - restrictive embodiment or aspect, the inner portion 107 and the outer portion 109 are at least two concentric circles. In a non - restrictive embodiment or aspect, at least one of the concentric circles has a width greater than the width of the other of the concentric circles. The locking spring washer 100 further includes one or more protrusions 110. In the illustrated embodiment or aspect, the protrusion includes a proximal (uppermost) and a distal (lowermost) end, and the protrusion 110 bridges the inner portion 107 and the outer portion 109 of the body, with a gap 120 between the proximal end of the protrusion 110 and the inner portion 107 and the outer portion 109 of the body. The protrusion 110 has a rectangle in Figure 5 ; however, the present disclosure is not limited thereto, and the protrusion 100 can take any useful shape or orientation, such as but not limited to an arc or an arch.

[0071] Moving on to Figure 6A - 6D , a schematic top view of the load spring washer 100 according to a non - restrictive embodiment or aspect is shown ( Figure 6A ), a side view ( Figure 6B ), a cross - sectional view ( Figure 6C ), and a perspective view ( Figure 6D ) are shown. The load spring washer 100 includes a body 105 and a protrusion 110. In the illustrated non - restrictive embodiment or aspect, the protrusion has a cylindrical shape, optionally with a dome 125 at the proximal (uppermost) end. In a non - restrictive embodiment or aspect, the interior of the cylinder can be hollow, thereby defining a chamber 130. The presence of the chamber 130 (which can be evacuated during manufacture so that there is no air therein) allows the dome (120) and / or the walls of the protrusion 110 to collapse or buckle inwardly towards the distal (lowermost) end of the load spring washer 100 when a force is applied to the load spring washer 100 in a direction parallel to the longitudinal axis defined by the proximal surface 101 and the distal surface 102 of the body 105. In a non - restrictive embodiment or aspect, the outermost perimeter of the body 105 can include one or more protrusions to provide a greater frictional engagement between the outer diameter of the body 105 and the inner diameter of a medical device housing into which the load spring washer 100 can be introduced.

[0072] Moving on to Figure 7A - 7C , a schematic top view ( Figure 7A ) and a side view ( Figure 7B - 7C ) of the load spring washer 100 according to a non - restrictive embodiment or aspect are shown. In the illustrated non - restrictive embodiment or aspect, the load spring washer 100 has a waveform. Although Figure 7B - 7CA sine wave including a peak 150 and a trough 140 is shown, but it should be understood that the present disclosure is not limited thereto, and various waveforms can be used, such as but not limited to square waves, sawtooth waves, and triangular waves, as long as the waveform provides the desired buckling characteristics described herein. Additionally, although not illustrated in Figure 7A - 7C , in non-limiting embodiments or aspects, the waveform load spring washer 100 further includes one or more protrusions 110 as described herein.

[0073] Moving on to Figure 8A - 8D , a top view ( Figure 8A ), side view ( Figure 8B ), cross-sectional view ( Figure 8C ), and perspective view ( Figure 8D ) of the load spring washer 100 according to non-limiting embodiments or aspects are shown. In the illustrated non-limiting embodiments or aspects, the load spring washer 100 includes a body 105 and a frustoconical portion 170 at the proximal (uppermost) end of the body 105. The frustoconical portion 170 can assume the orientation illustrated in Figure 8B - 8C (having a larger perimeter at its proximal end) or an inverted orientation (having a larger perimeter at its distal (lowermost) end, not shown). In the illustrated non-limiting embodiments or aspects, the portion of the frustoconical portion 170 having the larger perimeter is disposed at the proximal (uppermost) end, and a clearance 180 of height is defined between the proximal (uppermost) end of the frustoconical portion 170 and the proximal surface 101 of the body 105. In the illustrated non-limiting embodiments or aspects, when a force is applied to the load spring washer 110 in a direction parallel to the longitudinal axis defined by the proximal surface 101 and the distal surface 102 of the body 105, the lowermost end of the frustoconical portion 170 buckles towards the distal (lowermost) end of the load spring washer 100 such that the height of the clearance 180 is less than the height when no force is applied to the load spring washer 100.

[0074] Moving on to Figure 9A - 9B , a perspective view ( Figure 9A ) and a cross-sectional view ( Figure 9B ) of the load spring washer 100 according to non-limiting embodiments or aspects are shown. In the illustrated non-limiting embodiments or aspects, the load spring washer 100 has a frustoconical shape where the proximal surface 101 is narrower (smaller perimeter) than the distal surface 102, but the opposite orientation can be employed. In the illustrated non-limiting embodiments or aspects, when a force is applied to the load spring washer 110 in a direction parallel to the longitudinal axis defined by the proximal surface 101 and the distal surface 102, the proximal surface 101 buckles towards the distal surface 102 of the load spring washer 100.

[0075] Go to Figure 10A - 10B , showing a perspective view ( Figure 10A ) and a cross-sectional view ( Figure 10B ) of the load spring washer 100 according to a non-limiting embodiment or aspect. Figure 10A - 10B The load spring washer 100 illustrated in Figure 10B includes a protrusion 110. The protrusion 110 is oriented such that, as best illustrated in the cross-sectional view in Figure 10B , when considered together with the body 105, the protrusion provides a frustoconical shape to the load spring washer 100. In the illustrated non-limiting embodiment or aspect, when a force is applied to the load spring washer 110 in a direction parallel to the longitudinal axis defined by the proximal surface 101 and the distal surface 102 of the body 105, the protrusion 110 buckles towards the distal surface 102 of the load spring washer 100.

[0076] Go to Figure 12A - 12B , showing a non-limiting embodiment or aspect of a load spring washer 200, which includes a body 205 and at least one flange 210 and / or at least one arm 225. Figure 12B Shows the load spring washer 200 in a medical injection device housing 250. The flange 210 can be defined by a portion 215 extending outward from the outer diameter of the body 205 and a portion 220 extending substantially perpendicular to the portion 215. The lengths of the portion 215 and the portion 220 can be adjusted based on the medical device into which the load spring washer 200 is introduced.

[0077] The arm 225 can include a portion 215 extending outward from the outer diameter of the body 205 and a portion 220 extending substantially perpendicular to the portion 215. The arm 225 further includes a portion 230 extending substantially perpendicular to the portion 220. In a non-limiting embodiment or aspect, the portion 230 is substantially parallel to the portion 215.

[0078] Go to Figure 13A - 13B , showing a non-limiting embodiment or aspect of a load spring washer 300. Figure 13B Shows the load spring washer 300 in a medical injection device housing 350. In the illustrated non-limiting embodiment or aspect, the load spring washer 300 is an annular foam member.

[0079] Go to Figure 14A - 14B , showing a non-limiting embodiment or aspect of a load spring washer 400. Figure 14BShows a load spring washer 400 in a medical injection device housing 450. In the illustrated non - limiting embodiments or aspects, the load spring washer 400 includes one or more protrusions 410 and / or patterns cut into the proximal surface 401. In the illustrated non - limiting embodiments or aspects, the load spring washer 400 is an annular rubber - based member. Without wishing to be bound by theory, the applicant believes that the patterns allow buckling of the various parts of the load spring washer 400 as described herein.

[0080] Turn to Figure 15A - 15B , shows a non - limiting embodiment without a load spring washer. Instead, the brake tower 500 of the medical injection device (described in more detail below) includes one or more elastomeric protrusions 510 on its proximal surface. Without wishing to be bound by theory, the applicant believes that the elastomeric protrusions 510 allow buckling as described herein. Figure 15B Shows the brake tower 500 in a medical injection device housing 550.

[0081] Also provided herein is a medical injection device that includes a load spring washer as described above. By way of example and not limitation, such a device, such as an injection pen, is described in U.S. Patent No. 9,421,334, which is hereby incorporated by reference in its entirety. Refer to Figure 16 , shows an exploded view of an injection pen 51 for delivering a composition to a user. As shown, the injection pen 51 includes an upper pen body or housing 1 that houses a plurality of dose - setting and injection components. The upper pen body 1 is connected to a cartridge holder 14 that houses a drug cartridge 15. The injection pen 51 may also include a lower pen cap 12 to cover the cartridge 15 and the cartridge holder 14 when the injection pen is not in use. As shown, the injection pen 51 may include a dose - setting knob 2 that includes a knob - shaped portion that the user rotates to set a desired dose. The dose - setting knob 2 may also include a plurality of numbers corresponding to a number of dose units that are visible through a window 13 provided on the upper pen body 1. The user rotates the dose - setting knob 2 until the desired dose is visible in the window 13. The upper pen body 1 may include an arrow or other indicator 53 to precisely indicate the set dose. Once the desired dose is set, the user presses a button 3 until the set dose is fully injected. An outer shield 69 may cover the needle 56 to prevent accidental needle sticks when the lower pen cap 12 is removed.

[0082] The injection pen 51 includes a button 3 that is disposed at the proximal end of the pen upper body 1 closest to the user and farthest from the needle f18Ae56. The button 3 may include an annular crimp or edge 57 that engages a corresponding annular groove (not shown) disposed on the inner surface of the dose setting knob 2. The connection between the annular crimp and the groove may be a friction fit that holds the button 3 in a biased position on the dose setting knob 2 under the force of the button spring 10, but allows the button 3 to be pushed into the dose setting knob 2 to inject a set dose. The interior of the button 3 may house a setback bearing insert 8 that is seated on the inner surface at the proximal end of a retraction member or driver 9. The button 3 may be designed to rotate freely on the setback bearing insert 8.

[0083] The retraction member or driver 9 may be a cylindrical member that is coaxial with the dose setting knob 2 and surrounded by the dose setting knob 2. The retraction member 9 may be disposed coaxially around a brake tower 5 that is axially and rotatably fixed to the pen upper body 1. The brake tower 5 coaxially surrounds a piston rod 6. The piston rod 6 includes a set of keys 62 that engage slots (not shown) inside the brake tower 5 to rotatably lock the piston rod 6 to the brake tower 5. The piston rod 6 may include a plurality of threads (not shown) disposed on its inner surface. The piston rod 6 may coaxially surround a lead screw 4 that includes a series of threads 42 at least at its distal end. The threads 42 of the lead screw may be configured to threadedly engage internal threads (not shown) disposed on the interior of the piston rod 6. Due to its threaded engagement with the lead screw 4, the piston rod 6 may move into the barrel 15 during injection to press a stopper 16 disposed inside the barrel 15 to expel a set dose of the drug.

[0084] Referring to the present disclosure, the injection pen 51 includes a load spring washer 11 disposed between the distal end of the brake tower 5 and the barrel 15 and / or barrel holder 14 to bias the barrel 15 in the distal direction, thereby reducing / preventing movement of the barrel 15. Reducing and / or preventing movement of the barrel 15 may reduce a clicking sound and improve the situation of the needle 56 piercing into the barrel 15 before filling.

[0085] Example

[0086] The load spring washer is made of a highly elastic elastomeric material that includes the following components:

[0087] Table 1

[0088]

[0089]

[0090] As shown in Figure 11, the above materials are used to manufacture load spring washers of various orientations / shapes. The data is presented in the following table.

[0091] Table 2

[0092]

[0093] Table 3

[0094]

[0095]

[0096] In addition, data (compression load and compression elongation) from the above samples is presented in Figure 17 .

[0097] In addition, another 19 samples are produced from a silicone-based rubber material with a Shore A hardness of 35. A silicone rubber ring is cut using a cutting die with an outer diameter of 14 mm, and then the inner diameter is punched using a cutting die of 10 mm (samples 5, 6, and 7 in Tables 4 and 5) or 12 mm (others). These rings are cut from an ASTM rubber sheet that is 6.5 inches long × 6.5 inches wide and 1.8 - 2.0 mm thick. All samples in Tables 4 and 5 are the same test, but the force is specified at different compression distances. The maximum compression elongation is 1.5 mm.

[0098] Tables 6 and 7 are the same test, but the force is specified at different compression distances. The maximum compression elongation is 1.5 mm.

[0099] All samples in Tables 4 and 5, and Tables 6 and 7 are made in the same way by stamping rings from the rubber sheet, with the dimensions provided in Figure 18A - 18B ( Figure 18A is a top view, Figure 18B is a cross-sectional view) as follows:

[0100] Table 4

[0101]

[0102] Table 5

[0103]

[0104]

[0105] Finally, another 14 samples are produced, with the dimensions provided in Figure 19A - 19B ( Figure 19A is a top view, Figure 19B is a cross-sectional view) as follows:

[0106] Table 6

[0107]

[0108]

[0109] Table 7

[0110]

[0111]

[0112] The rings tested in Tables 4 and 5 and Tables 6 and 8 operated as expected, showing different buckling grades and limiting the development force of compression extension to less than 1.5 mm. The variation in the maximum compression force was caused by the ring width of 1.5 mm for Samples 5, 6, and 7 in Tables 4 and 5 or the variation in stamping and centering of the die during ring manufacturing. In fact, the variability of the process produces an asymmetric cross-section of the ring, which contributes to the buckling concept approach.

[0113] Although the device has been described in detail for purposes of illustration based on the presently considered to be the most practical and preferred embodiments, it should be understood that such details are for that purpose only and that the system and method are not limited to the disclosed embodiments. On the contrary, this application is intended to cover modifications and equivalent arrangements within the spirit and scope of the appended claims. For example, it should be understood that this system and method contemplate that, to the extent possible, one or more features of any embodiment may be combined with one or more features of any other embodiment.

Claims

1. A medical injection device, comprising: a housing having a proximal end, a distal end, and a sidewall between the proximal end and the distal end, the housing defining an interior; a braking member received within the interior of the housing; a barrel holder received within the interior of the housing distal to the braking member; a barrel received within the barrel holder and holding a composition therein; a load spring washer comprising: a body having a proximal surface and a distal surface; and one or more protrusions extending proximally outwardly from the proximal surface and away from the proximal surface of the body, the load spring washer being received within the interior of the housing and positioned between the braking member and the barrel holder such that when the medical injection device is assembled, the one or more protrusions abut the braking member and the distal surface abuts the barrel and / or the barrel holder; an injection needle in fluid communication with the barrel and disposed at the distal end of the housing; and an actuating member disposed at the proximal end of the housing, the actuating member being configured to actuate the medical injection device to deliver the composition through the injection needle; wherein the protrusions are formed of an elastomeric material.

2. The medical injection device according to claim 1, wherein a cross-sectional profile of the one or more protrusions of the load spring washer taken along a plane extending between the proximal surface and the distal surface includes a parallelogram.

3. The medical injection device according to claim 1, wherein a cross-sectional profile of the one or more protrusions of the load spring washer taken along a plane extending between the proximal surface and the distal surface includes a cylinder.

4. The medical injection device according to claim 3, wherein the cylinder defines a hollow interior.

5. The medical injection device according to claim 4, wherein the hollow interior is filled with gas.

6. The medical injection device according to claim 4, wherein the hollow interior contains a vacuum.

7. The medical injection device according to claim 1, wherein a cross-sectional profile of the one or more protrusions of the load spring washer taken along a plane extending between the proximal surface and the distal surface includes a rhombus.

8. The medical injection device according to claim 1, wherein a cross-sectional profile of the one or more protrusions of the load spring washer taken along a plane extending between the proximal surface and the distal surface includes an S shape.

9. The medical injection device according to claim 1, wherein a cross-sectional profile of the one or more protrusions of the load spring washer taken along a plane extending between the proximal surface and the distal surface includes an L shape.

10. The medical injection device according to claim 1, wherein the body of the load spring washer includes a plurality of rings.

11. The medical injection device according to claim 10, wherein, the plurality of rings includes concentric circles, with a gap between each pair of concentric circles.

12. The medical injection device according to claim 11, wherein, at least one of the concentric circles has a width greater than that of another of the concentric circles.

13. The medical injection device according to claim 10, wherein, a cross-sectional profile of the one or more protrusions of the load spring washer, taken along a plane extending between the proximal surface and the distal surface, includes a U shape, where the U shape includes: a first arm connected to a first ring of the plurality of rings of the body and a second arm connected to a second ring of the plurality of rings of the body, the first arm and the second arm extending parallel to a longitudinal axis defined by the proximal surface and the distal surface of the body; and a transverse member connecting the first arm and the second arm and extending perpendicular to the longitudinal axis defined by the proximal surface and the distal surface of the body.

14. The medical injection device according to claim 10, wherein, the one or more protrusions of the load spring washer include an arch, the arch including: a first arm connected to a first ring of the plurality of rings of the body and a second arm connected to a second ring of the plurality of rings of the body, the first arm and the second arm extending parallel to a longitudinal axis defined by the proximal surface and the distal surface of the body; and a curved portion connecting the first arm and the second arm.

15. The medical injection device according to claim 1, wherein, the one or more protrusions of the load spring washer include a frustoconical portion.

16. The medical injection device according to claim 1, wherein, the load spring washer includes an elastomeric material.

17. The medical injection device according to claim 16, wherein, the load spring washer includes ethylene propylene diene monomer rubber.

18. The medical injection device according to claim 16, wherein, the load spring washer has a Shore A hardness of 20 - 40.

19. A load spring washer configured to bias an injection subassembly of a medical injection device, the load spring washer comprising: a circular body having a proximal surface and a distal surface, the distal surface being configured to abut a barrel holder and / or a barrel of the medical injection device; and one or more protrusions extending proximally outward from the proximal surface and away from the proximal surface of the circular body, wherein the one or more protrusions are configured to abut a braking member of the medical injection device; wherein, the protrusions are formed of an elastomeric material.

20. The load spring washer according to claim 19, wherein, the load spring washer includes an elastomeric material having a Shore A hardness of 20 - 40.

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