DIAL MECHANISMS FOR AN INJECTION DEVICE
Priority
[0001] The present application claims priority to U.S. Provisional Patent Application No. 63/459,657, filed on April 16, 2023, the entire disclosure of which is expressly incorporated herein by reference.
Technical Field
[0002] The present disclosure relates generally to dial mechanisms for injection pens driven by a torsion spring.
Background
[0003] Dosing mechanisms for injection devices driven by torsion springs are set by a user rotating a dose setting member. The rotational force applied to the dose setting member is stored in the torsion spring for subsequently driving an injection. The strain of the torsion spring being in the same direction as the dose setting can provide some difficulties in reducing the tension of the torsion spring in a controlled manner during a dose correction (reducing a set dose). Current wind-up pens provide dial mechanisms with the possibility of rotating the dose setting member in an opposite direction to reduce the set dose prior to dose delivery.
Summary
[0004] However, the present inventors recognize the current dial mechanisms can have deficiencies that create suboptimal handling by the user and/or difficulty in manufacturing. For example, some dial mechanisms require small components that are not easily manufactured and tend to break under the required torsional strains. Some dial mechanisms may also require excessive torque during dose setting, which is suboptimal especially for users with limited dexterity. Furthermore, when the dial mechanisms require excessive torque during dose setting, there may be a tendency to skip doses during dose setting and/or dose correction. One or more of the foregoing needs or other needs in the art are met by the injection devices described herein.
[0005] Thus, in a first embodiment, an injection device may include: a housing; a dial member configured to be rotated to set a dose of medicament; a drive sleeve configured to be rotated by the dial member; a dial sleeve disposed around the drive sleeve, wherein the dial sleeve includes one or more pawl beams having first and second fixed opposing ends; a torsion spring having a first end fixed relative to the housing and a second end fixed relative to the drive sleeve and/or the dial sleeve; and a clutch ring configured to engage the one or more pawl beams so as to selectively resist rotation of the dial sleeve, where the one or more pawl beams may be configured to deflect radially inward to enable rotation of the drive sleeve during rotation of the dial member.
[0006] In the first embodiment, the one or more pawl beams may be defined by a respective circumferential slot extending through the dial sleeve. Each of the circumferential slots may have closed ends and extend only partially along a circumference of the dial sleeve. Each of the one or more pawl beams may include a radial protrusion extending from a central portion of the one or more pawl beams, and each radial protrusion may be configured to be received between a plurality of inner teeth of the clutch ring. Each radial protrusion may have a rounded radially outer surface configured to engage grooves between the plurality of inner teeth of the clutch ring. Each radial protrusion may have a shape that complements or matches a shape of the plurality of inner teeth of the clutch ring. Each radial protrusion may be asymmetric. The drive sleeve may be rotationally fixed to the dial sleeve. The drive sleeve may have an outer protrusion, the dial sleeve may have an inner slot, and the outer protrusion may be received in the inner slot. The dial sleeve may include one or more retention arms configured to engage a distal surface of the clutch ring to axially secure the dial sleeve to the clutch ring. The distal surface may be on an inner flange of the clutch ring. The clutch ring may be advanced distally by axial translation of the drive sleeve to initiate injection of the dose. A scale drum may be rotationally fixed to the dial sleeve, the scale drum having indicia formed or printed on an outer surface in a helically arranged pattern. The one or more pawl beams may be configured to deflect radially inward during rotation of the dial member in a first rotational direction that decreases tension of the torsion spring and during rotation of the dial member in a second rotational direction that increases tension of the torsion spring.
[0007] in a second embodiment, an injection device may include: a housing; a dial member configured to be rotated to set a dose of medicament; a drive sleeve configured to be rotated by the dial member; a dial sleeve disposed around the drive sleeve; a torsion spring having a first end fixed relative to the housing and a second end fixed relative to the drive sleeve and/or the dial sleeve; and a clutch ring configured to engage the dial sleeve so as to selectively resist rotation of the dial sleeve, where rotation of the drive sleeve may be configured to longitudinally translate the dial sleeve relative to the clutch ring to enable rotation of the drive sleeve during rotation of the dial member. [0008] In the second embodiment, the dial sleeve may be longitudinally translated relative to the clutch ring during clockwise rotation of the dial member that decreases tension on the torsion spring and during counterclockwise rotation of the dial member that increases tension on the torsion spring. The drive sleeve may include one or more pins, the dial sleeve may include one or more slots, and travel of the one or more pins in the one or more slots may be configured to longitudinally translate the dial sleeve relative to the clutch ring. Each of the one or more slots may be substantially V-shaped. The dial sleeve may include one or more pawl arms configured to engage a plurality of inner teeth on the clutch ring to resist rotation of the dial sleeve in a distal position, and longitudinal translation of the dial sleeve may move the one or more pawl arms proximally relative to the plurality of inner teeth to enable rotation of the drive sleeve to set the dose. Each of the one or more pawl arms may include a radial protrusion configured to be received between the plurality of inner teeth. The inner teeth may include a distal portion having a first rotational resistance and a proximal portion having a second rotational resistance, and the first rotational resistance may be greater than the second rotational resistance. The one or more pawl arms may be flexibly cantilevered, such that the one or more pawl arms may be configured to pivot inwardly relative to the plurality of inner teeth when the dial sleeve translates longitudinally to enable rotation of the drive sleeve. The dial sleeve may include one or more retention arms configured to engage a distal surface of the clutch ring to axially secure the dial sleeve to the clutch ring. Each of the one or more retention arms may include a spring extension configured to deflect during axial translation of the dial sleeve and to bias the dial sleeve into engagement with the clutch ring. The spring extension may have a cantilevered configuration. The distal surface may be on an inner flange of the clutch ring. The clutch ring may be advanced distally by axial translation of the drive sleeve to initiate injection of the dose. A scale drum may be rotationally fixed to the dial sleeve, the scale drum having indicia formed or printed on an outer surface in a helically arranged pattern.
[0009] In a third embodiment, an injection device may include: a housing; a dial member configured to be rotated to set a dose of medicament; a drive sleeve configured to be rotated by the dial member, the drive sleeve having one or more pawl arms; a dial sleeve disposed around the drive sleeve, the dial sleeve having one or more channels that receives the one or more pawl arms; a torsion spring having a first end fixed relative to the housing and a second end fixed relative to the drive sleeve and/or the dial sleeve; and a clutch ring configured to engage the one or more pawl arms to resist rotation of the dial sleeve, where relative rotation between the drive sleeve and the dial sleeve may be configured to cause the one or more pawl arms to follow the one or more channels to radially deflect the one or more pawl arms relative to the clutch ring, thus enabling rotation of the drive sleeve during rotation of the dial member.
[0010] In the third embodiment, the one or more channels may include one or more angled segments angled relative to a circumference of the dial sleeve. The one or more channels may be substantially V-shaped. The drive sleeve may include one or more fixed arms each having an outer radial dimension less than an inner radial dimension of a plurality of inner teeth of the clutch ring. The dial sleeve may include one or more curved channels configured to receive the one or more fixed arms. The dial sleeve may include one or more retention arms configured to engage a distal surface of the clutch ring to axially secure the dial sleeve to the clutch ring. The one or more pawl arms may extend circumferentially from the dial sleeve. Each of the one or more pawl arms may include a free end and a protrusion extending proximally from the free end. The protrusion may include a first portion having a first diameter, a second portion having a second diameter, wherein the first diameter may be greater than the second diameter, the first portion being configured to engage the clutch ring and the second portion being received by the one or more channels. The clutch ring may be advanced distally by axial translation of the drive sleeve to initiate injection of the dose. A scale drum may be rotationally fixed to the dial sleeve, the scale drum having indicia formed or printed on an outer surface in a helically arranged pattern.
[0011] In a fourth embodiment, an injection device may include: a housing; a dial member configured to be rotated to set a dose of medicament; a drive sleeve configured to be rotated by the dial member; a dial sleeve disposed around the drive sleeve, the dial sleeve including a plurality of proximal teeth; a torsion spring having a first end fixed relative to the housing and a second end fixed relative to the drive sleeve and/or the dial sleeve; a clutch ring including a plurality of distal teeth; and a spring configured to bias the plurality of distal teeth into engagement with the plurality of proximal teeth to resist rotation of the dial sleeve, wherein rotation of the dial sleeve relative to the clutch ring may be configured to compress the spring and advance the clutch ring distally to enable rotation of the drive sleeve during rotation of the dial member.
[0012] In the fourth embodiment, the plurality of proximal teeth and the plurality of distal teeth may enable two-way rotation of the dial sleeve relative to the clutch ring. The plurality of proximal teeth and the plurality of distal teeth may be asymmetrical. The dial sleeve may have a distal portion of reduced diameter, and the spring may be positioned around the distal portion. A retention ring may be at the distal portion of the dial sleeve, wherein the spring extends between the retention ring and the clutch ring. The retention ring may include radial protrusions, and the dial sleeve includes radial channels, wherein the radial protrusions may be received in the radial channels to secure the retention ring at the distal portion of the dial sleeve. The drive sleeve may be rotationally fixed to the dial sleeve. The drive sleeve may have an outer protrusion, the dial sleeve has an inner slot, and the outer protrusion may be received in the inner slot. The clutch ring may be advanced distally by axial translation of the drive sleeve to initiate injection of the dose. The clutch ring may be configured to advance distally a first distance to set a dose of medicament and advance distally a second distance that may be greater than a first distance to initiate injection of the dose. Rotation of the dial member in a first rotational direction may be configured to increase tension on the torsion spring and rotation of the dial member in a second rotational direction opposite the first rotational direction may be configured to decrease tension on the torsion spring. A first minimum rotational force may be required to rotate the dial member in the first rotational direction, and a second minimum rotational force that may be greater than the first minimum rotational force may be required to rotate the dial member in the second rotational direction. A scale drum may be rotationally fixed to the dial sleeve, the scale drum having indicia formed or printed on an outer surface in a helically arranged pattern.
Brief Description of the Drawings
[0013] In order that the disclosure may be readily understood, aspects of this disclosure are illustrated by way of examples in the accompanying drawings.
[0014] FIG. 1 illustrates an isometric view of an exemplary injection device.
[0015] FIG. 2 illustrates an isometric view of the injection device of FIG. 1 with a cap removed.
[0016] FIG. 3 illustrates a side view of a cross-section of a first embodiment of the injection device of FIG. 1.
[0017] FIG. 4 illustrates an isometric view of components of the first embodiment of FIG. 3. [0018] FIG. 5 illustrates an isometric view of a partial cross-section of a dial mechanism of the first embodiment of FIGS. 3 and 4.
[0019] FIG. 6 illustrates a side view of a cross-section of a clutch ring of the first embodiment of FIGS. 3-5.
[0020] FIG. 7 illustrates a side view of a distal portion of a dial sleeve of the first embodiment of FIGS. 3-6. [0021] FIG. 8 illustrates a side view of a cross-section of a second embodiment of the injection device of FIG. 1.
[0022] FIG. 9 illustrates an isometric view of components of the second embodiment of FIG.
8.
[0023] FIG. 10 illustrates a side view of a cross-section of a dial mechanism of the second embodiment of FIGS. 8 and 9.
[0024] FIG. 11 illustrates an isometric view of a partial cross-section of the dial mechanism of the second embodiment of FIGS. 8-10.
[0025] FIG. 12 illustrates an isometric view of a drive sleeve of the second embodiment of FIGS. 8-11.
[0026] FIG. 13 illustrates an isometric view of a cross-section of the dial sleeve of the second embodiment of FIGS. 8-12.
[0027] FIG. 14 illustrates a bottom view of the dial mechanism of the second embodiment of FIGS. 8-13 with a clutch ring being transparent.
[0028] FIG. 15 illustrates a side view of a cross-section of a third embodiment of the injection device of FIG. 1.
[0029] FIG. 16 illustrates an isometric view of components of the third embodiment of FIG.
15.
[0030] FIG. 17 illustrates an isometric view of a dial sleeve of the third embodiment of FIGS.
15 and 16.
[0031] FIG. 18 illustrates an isometric view of view of a dial mechanism of the third embodiment of FIGS. 15-17 with the dial sleeve being transparent.
[0032] FIG. 19 illustrates a side view of a cross-section of a fourth embodiment of the injection device of FIG. 1.
[0033] FIG. 20 illustrates an isometric view of components of the fourth embodiment of FIG. 19.
[0034] FIG. 21 illustrates an isometric view of a retention ring of the fourth embodiment of FIGS. 19 and 20.
[0035] FIG. 22 illustrates a side view of a dial sleeve of the fourth embodiment of FIGS. 19- 21.
[0036] FIG. 23 illustrates a side view of a dial mechanism of the fourth embodiment of FIGS. 19-22.
[0037] The same reference numbers are used in the drawings and the following detailed description to refer to the same or similar parts. Detailed Description
[0038] The present invention relates to various embodiments of a dial mechanism for an injection device comprising a torsion spring configured to assist injection of a dose of medicament.
[0039] As used herein, the term “medicament” refers to any drug-containing flowable medicine, such as a liquid, solution, gel or fine suspension. Representative drugs include pharmaceuticals such as peptides, proteins (e.g., insulin, insulin analogues, and C-peptide), and hormones, biologically derived or active agents, hormonal and gene-based agents, nutritional formulas and other substances in both solid (dispensed) or liquid form. The medicament may include parathyroid hormone, a luteinising hormone, a follicle-stimulating hormone, an insulin, a GLP-1 agonist, a GIP agonist, a glucagon receptor agonist, an amyl in analogue, and/or combinations thereof. For example, the medicament may include one or more of teriparatide, abaloparatide, liraglutide, semaglutide, tirzepatide, and cagrilintide. [0040] Except when otherwise indicated, the term “distal” or “distally” refers to a position of the injection device or a respective component closer to an injection site as intendedly used. The term “proximal” or “proximally” refers to a position of the injection device or the component closer to end opposite of the injection site as intendedly used. The term “axial” or “axially” refers to a length or direction that is along or parallel to a longitudinal axis of the injection device or the component. The term “radial” or “radially” refers to a length or direction perpendicular to the longitudinal axis of the injection device or the component. The term “circumferential” or “circumferentially” refers to a length or direction extending at least partially around the longitudinal axis of the injection device or the component. The terms “clockwise” and “counterclockwise” refers to a circumferential direction of the injection device or the component when viewed from the proximal direction.
[0041] FIGS. 1 and 2 illustrate an injection device 100 having a housing 102, a cartridge holder 104 retained at a distal end of the housing 102, and a cap 106 configured to releasably cover the cartridge holder 104. The cartridge holder 104 may be configured to hold a cartridge 108 filled with a medicament and being sealed by a distal needle-penetrable septum. The cartridge holder 104 may include one or more windows allowing a portion of the cartridge 108 to be inspected. The cartridge holder 104 may further include a coupling member 110 at a distal end configured to releasably mount a needle assembly (not shown). The cartridge 108 may have a piston driven by a drive mechanism to inject a set dose of the medicament. The housing 102 may include a distal opening having one or more grooves configured to retain one or more ribs on a proximal end of the cartridge holder 104 to secure the cartridge holder 104 to the housing 102. The injection device 100 may be disposable or reusable. For example, when disposable, the injection device 100 may be used multiple times to inject multiple doses but disposed of when the cartridge 108 is disposable. When reusable, the cartridge holder 104 may be removed from the housing 102, such that the cartridge 108 is replaced when empty and the piston is returned to a zero position.
[0042] The injection device 100 may further include a dose setting member 112 and a button 114. The dose setting member 112 may be configured to manually set a desired dose of the medicament that is displayed with indicia 120 through a display window 116 of the housing 102. The dose setting member 112 may have a generally cylindrical outer surface that is slightly tapered. The dose setting member 112 may be textured with circumferentially oriented fine grooves and a plurality of axially oriented grooves 118 to improve finger grip during dose setting. The display window 116 may have a dose pointer 122 selectively aligned with the indicia 120 formed or printed on a scale drum 124 and visible through the display window 116. As such, the indicia 120 on the scale drum 124 are viewable at fixed location defined by the display window 116 of the housing 102. The indicia 120 may be aligned in a helically arranged pattern on an outer surface of the scale drum 124, such that rotation and axial translation of the scale drum 124 relative to the housing 102 may cause the indicia 120 corresponding to the set dose to be visible through the display window 116.
[0043] FIGS. 3-7 illustrate a first embodiment of an injection device 200 consistent with the disclosure of the injection device 100 as illustrated in FIGS. 1 and 2, the disclosure of which is incorporated herein by reference to describe the injection device 200.
[0044] As further illustrated in FIG. 3, the injection device 200 may have a housing 202 with a proximal skirt portion 226 provided with a circumferential ridge 228 configured to rotationally mount a dial member 212 in a snap coupling. A torsion spring 230 may extend longitudinally through the housing 202. A proximal end of the torsion spring 230 may be fixed relative to the housing 202, for example, by a loop on a proximal end of the torsion spring 230 secured to a proximal ring 232 that is fixed longitudinally and rotationally to the housing 202. A distal end of the torsion spring 230 may be fixed relative to a distal portion of a drive sleeve 234 and/or a dial sleeve 240, for example, by a loop on a distal end of the torsion spring 230 secured to the distal portion of the drive sleeve 234 and/or the dial sleeve 240. In a preferred embodiment, the distal end of the torsion spring 230 may be secured directly to the dial sleeve 240 to facilitate assembly. The drive sleeve 234 may extend longitudinally through the housing 202 inside of the torsion spring 230. The drive sleeve 234 may include a plurality of outer teeth 236 at a proximal portion splined to a plurality of inner teeth or longitudinal grooves (not shown) on the dial member 212. Thus, the drive sleeve 234 may have a proximal position rotationally fixed to the dial member 212 when the injection device 200 is configured to set a dose, such that rotation of the dial member 212 rotates the drive sleeve 234 that in turn rotationally tensions the torsion spring 230 to increase a set dose or removes tension from the torsion spring 230 to decrease a set dose.
[0045] The drive sleeve 234 may be secured to the dial sleeve 240 that is rotationally fixed to a scale drum 224. The dial sleeve 240 may extend longitudinally through the housing 202 around the torsion spring 230, such that the torsion spring 230 extends between the drive sleeve 234 and the dial sleeve 240. The dial sleeve 240 may have a plurality of longitudinal splines 242 on an outer surface received in a plurality of longitudinal grooves on an inner surface of the scale drum 224. Thus, the scale drum 224 is rotationally fixed to the dial sleeve 240 but axially movable along the outer surface of the dial sleeve 240. The scale drum 224 may be threaded to an inner surface of the housing 202, for example, by a helical groove 244 in an outer surface of the scale drum 224 receiving a helical protrusion on an inner surface of the housing 202. The scale drum 224 may have indicia formed or printed on an outer surface (as illustrated in FIGS. 1 and 2) in a helically arranged pattern. Thus, rotation of the drive sleeve 234 with the dial member 212 causes rotation of the dial sleeve 240 that in turn causes the scale drum 224 to rotate and translate helically relative to the housing 202. The helical rotation of the scale drum 224 exposes the indicia through a window 216 that indicates the dose set corresponding to the tensioning of the torsion spring 230.
[0046] The injection device 200 may include a dial mechanism configured to enable incremental dose setting while preventing release of the tension in the torsion spring 230 before initiating injection. The dial mechanism may include a clutch ring 250 having a plurality of outer teeth 252 and a plurality of inner teeth 254. The outer teeth 252 may be configured to engage the housing 202 to rotationally fix the clutch ring 250 during dose setting and be disengaged from the housing 202 during dose delivery (as further discussed below). The plurality of inner teeth 254 may be configured to engage one or more pawl arms 256 to resist rotation of the drive sleeve 234. Each of the pawl arms 256 may have a radial protrusion 258 extending radially from the one or more pawl arm 256 and being configured to be received between the inner teeth 254 of the clutch ring 250. The radial protrusion 258 may strike the clutch ring 250 to generate an audible and/or tactile click for each dose unit being dialed. The one or more pawl arms 256 may extend longitudinally from a distal portion of the dial sleeve 240. [0047] The dial mechanism may include a pin and track mechanism configured to move the dial sleeve 240 including the one or more pawl arms 256 longitudinally in a proximal direction relative to the clutch ring 250 during dose setting by rotation of the drive sleeve 234. For example, the drive sleeve 234 may include one or more pins 260, and the dial sleeve 240 may include one or more slots 262 receiving the one or more pins 260. The one or more slots 262 may have one or more angled segments 261 angled relative to a longitudinal axis of the dial sleeve 240, such that travel of the pins 260 into the angled segments 261 is configured to longitudinally translate the dial sleeve 240 proximally relative to the clutch ring 250 lifting the one or more pawl arms 256 relative to the inner teeth 254 of the clutch ring 250. As illustrated, each of the slots 262 may include a pair of the angled segments 261 extending distally at an angle and joined at an apex 263, being substantially V-shaped. The lifting of the one or more pawl arms 256 enables rotation of the drive sleeve 234 relative to the clutch ring 250 to increase or decrease a set dose incrementally by a single dose unit. Thus, the one or more pins 260 may be biased into the apex 263 such that the one or more pawl arms 256 are in a distal position when the user is not applying a dialling torque. For example, the one or more pins 260 may be rotated in a counterclockwise direction into a first of the angled segments 261 when the user dials up the dose (increasing tension on the torsion spring 230) to lift the one or more pawl arms 256 into a proximal position relative to the clutch ring 250. The one or more pins 260 may also be rotated in a clockwise direction into a second of the angled segments 261 when the user dials down the dose (decreasing tension on the torsion spring 230) to lift the one or more pawl arms 256 into the proximal position relative to the clutch ring 250. However, it is contemplated that the directions of rotation could be reversed for dial up and dial down.
[0048] The inner teeth 254 may have a root forming a distal portion 264 with a first rotational resistance to the one or more pawl arms 256 and a tip forming a proximal portion 265 having a second rotational resistance to the one or more pawl arms 256. The distal portion 264 may be formed by surfaces extending at a first angle relative to a longitudinal axis of the dial sleeve 240 to prevent rotational movement of the one or more pawl arms 256 when in the one or more pawl arms 256 are in the distal position. For example, the surfaces of the distal portions 264 may be flat and substantially parallel to the longitudinal axis of the dial sleeve 240. The proximal portion 265 may include surfaces to allow relative rotation of the dial sleeve 240 when the one or more pawl arms 256 are in the proximal position (i.e., when the one or more pins 260 is rotated into one of the angled segments 261 to lift the one or more pawl arms 256 into a proximal position relative to the clutch ring 250). The surfaces of the proximal portion 265 may extend at a second angle relative to the longitudinal axis, and the second angle may be larger than the first angle, such the tip of the proximal portion 265 is narrower than the root of the distal portion 264. The one or more pawl arms 256 may be flexible and cantilevered. The proximal portion 265 may further have an interior surface being radially chamfered to pivot the one or more pawl arms 256 inwardly as the one or more pawl arms 256 ride over the inner teeth 254. Such a configuration provides favorable tactile feedback and resistance during dose setting. The proximal portion 265 may additionally or alternatively be curved or arcuate.
[0049] In some embodiments (not shown), the inner teeth 254 of the clutch ring 250 may have a sawtooth profile acting in a radial direction when viewed from the proximal end. The one or more pawl arms 256 may have a constant cross-section along their length, omitting the radial protrusion 258. The geometry of the outer surface of the one or more pawl arms 256 may be configured to match or complement the internal sawtooth profile of the clutch ring 250. When the dial sleeve 234 is in the distal position, the teeth on the clutch ring act near the root of the one or more pawl arms 256, resisting rotation. When the dial sleeve 234 is in the proximal position, the inner teeth 254 on the clutch ring 250 engage the distal end of the pawl arms 256, which can deflect inwards more readily, allowing the dial sleeve 234 to be rotated when dose setting or dose correcting, as discussed herein.
[0050] After the dose is increased or decreased, a bias of the dial sleeve 240 may push the one or more pawl arms 256 back into the distal position with the pin 260 at the apex 263 to prevent further winding or unwinding of the torsion spring 230. For example, the dial sleeve 240 may include one or more retention arms 266 configured to longitudinally bias the one or more pawl arms 256 distally between the distal portions 264 of the inner teeth 254. The one or more retention arms 266 may include a longitudinal portion 267 and a spring extension 268 in the form of a living spring configured to bias the dial sleeve 240 distally relative to the clutch ring 250. The one or more retention arms 266 may further include an outer flange 272 extending radially from the longitudinal portion 267 and forming an attachment with the one or more spring extensions 268. The outer flange 272 may be configured to engage an inner flange 270 of the clutch ring 250 to axially secure the clutch ring 250, preventing the clutch ring 250 from being pulled off of the dial sleeve 240. The spring extension 268 may extend circumferentially from the outer flange 272 and engage a distal surface of the inner flange 270 of the clutch ring 250. The spring extension 268 may have a cantilevered configuration, with a fixed end attached to the outer flange 272 and a free end engaging the distal surface of the inner flange 270. With the one or more pawl arms 256 in the distal position, the spring extension 268 may laterally extend from the longitudinal portion at an angle relative to a circumference of the dial sleeve 240 (e.g., as illustrated in FIGS. 5 and 7) to bias the dial sleeve 240 distally relative to the clutch ring 250. During dose setting with the one or more pawl arms 256 in the proximal position, the longitudinal translation of the dial sleeve 240 may deflect the spring extension 268 by reducing the angle of the spring extension 268 relative to the circumference of the dial sleeve 240. After the one or more pawl arms 256 ride over the inner teeth 254 of the clutch ring 250, the bias of the one or more spring extensions 268 may pull the one or more pawl arms 256 back distally into the distal position to rotationally fix the dial sleeve 240 to the clutch ring 250. Thus, the one or more retention arms 266 may be longer than the one or more pawl arms 256 to engage the distal surface of the inner flange 270, and the retention arms 266 may provide a constant engagement with the clutch ring 250.
[0051] Thus, the drive sleeve 234 and the dial sleeve 240 may be rotated and longitudinally translated relative to each other in small increments (as discussed above). The one or more pawl arms 256 and/or retention arms 266 (including the spring extensions 268) may be integrally and/or monolithically formed on the distal portion of the dial sleeve 240. As illustrated, the dial sleeve may include a plurality of the pawl arms 256 and a plurality of the retention arms 266 alternating and symmetrically arranged around a longitudinal axis of the dial sleeve 240.
[0052] As illustrated in FIG. 3, the injection device 200 may include a drive mechanism configured to release tension from the torsion spring 230 to deliver the dose of medicament set by the dial mechanism. The drive mechanism may include a threaded piston rod 280, a nut element 282, and a drive element 284. The threaded piston rod 280 may be rotationally received in a threaded opening of the nut element 282 that is rotationally and longitudinally fixed inside of the housing 202. The threaded piston rod 280 may have opposing longitudinal grooves interrupting the thread configured to rotationally fix the threaded piston rod 280 to inner protrusions of the drive element 284. The drive element 284 may be rotationally fixed to the clutch ring 250 and be configured to rotate relative to the housing 202. The drive element 284 may further include a pair of opposed circumferentially extending flexible ratchet arms configured to engage corresponding ratchet teeth on an inner surface of the housing 202 to provide a one-way rotational engagement with the housing 202. The drive element 284 and the clutch ring 250 may be rotationally fixed by cooperating coupling structures that allow the clutch ring 250 to be moved axially relative to the drive element 284. As discussed above, the outer teeth 252 of the clutch ring 250 may be configured to rotationally fix the clutch ring 250 when in a proximal position to the housing 202 that also rotationally fixes the drive element 284 during dose setting.
[0053] The injection may be initiated by a user pressing distally on the button 214. The button 214 may axially engage the drive sleeve 234, while the drive sleeve 234 is configured to rotate relative to the button 214. Thus, the distal pressing of the button 214 causes distal movement of the drive sleeve 234 to disengage the outer teeth 236 of the drive sleeve 234 from the dial member 212 to rotationally disengage the drive sleeve 234 from the dial member 212. A button spring (not shown) may bias the button 214 to a proximal position disengaging the drive mechanism.
[0054] The distal axial displacement of the drive sleeve 234 longitudinally translates the clutch ring 250 relative to the housing 202 to a distal position. In the distal position of the clutch ring 250, the outer teeth 252 are disengaged from the housing 202 to enable rotation of the clutch ring 250 relative to the housing 202. The clutch ring 250 is rotationally fixed to the dial sleeve 240 that is rotationally secured to the drive sleeve 234. Thus, when the clutch ring 250 is moved into the distal position, the torsion spring 230 is free to rotate the drive sleeve 234, the dial sleeve 240, and the clutch ring 250. The clutch ring 250 is rotationally fixed to the drive element 284 that rotates the threaded piston rod 280 through the nut element 282. The threaded engagement of the nut element 282 causes the rotating piston rod 280 to longitudinally translate and push the stopper through the cartridge to expel the medicament. Rotation of the dial sleeve 240 also causes the scale drum 224 to rotate and return to a “zero” position. The torsion spring 230 may still be tensioned in the “zero” position due the torsion spring 230 being preloaded during assembly to deliver both small and large doses within an acceptable speed interval, time interval, or duration.
[0055] As further illustrated in FIG. 3, the injection device 200 may have an end-of-content (EOC) member 286 configured to prevent the user from setting a larger dose than the amount of medicament remaining in the cartridge. The EOC member 286 is threaded over the piston rod 280 and rotationally locked to the drive sleeve 234. The EOC member 286 rotates during dose setting and dose correction as the drive sleeve 234 rotates, and moves axially back and forth following the thread of the piston rod 280. The EOC member 286 is configured to engage a stop at a proximal portion of the piston rod 280. The stop corresponds to an end of the medicament in the cartridge and prevents the dial sleeve 240, the drive sleeve 234, and the dial member 212 from further rotating to increase the dose. The relative position of the EOC member 286 remains stationary during dose delivery because the drive sleeve 234 and the piston rod 280 rotate together. [0056] FIGS. 8-14 illustrate a second embodiment of an injection device 300 consistent with the disclosure of the injection device 100 as illustrated in FIGS. 1 and 2, the disclosure of which is incorporated herein by reference to describe the injection device 300.
[0057] As further illustrated in FIG. 8, the injection device 300 may have a housing 302 with a proximal skirt portion 326 provided with a circumferential ridge 328 configured to rotationally mount a dial member 312 in a snap coupling. A torsion spring 330 may extend longitudinally through the housing 302. A proximal end of the torsion spring 330 may be fixed relative to the housing 302, for example, by a loop on a proximal end of the torsion spring 330 secured to a proximal ring 332 that is fixed longitudinally and rotationally to the housing 302. A distal end of the torsion spring 330 may be fixed relative to a distal portion of a drive sleeve 334 and/or a dial sleeve 340, for example, by a loop on a distal end of the torsion spring 330 secured to the distal portion of the drive sleeve 334 and/or the dial sleeve 340. In a preferred embodiment, the distal end of the torsion spring 330 may be secured directly to the dial sleeve 340 to facilitate assembly. The drive sleeve 334 may extend longitudinally through the housing 302 inside of the torsion spring 330. The drive sleeve 334 may include a plurality of outer teeth 336 at a proximal portion splined to a plurality of inner teeth or longitudinal grooves (not shown) on the dial member 312. Thus, the drive sleeve 334 may have a proximal position rotationally fixed to the dial member 312 when the injection device 300 is configured to set a dose, such that rotation of the dial member 312 rotates the drive sleeve 334 that in turn rotationally tensions the torsion spring 330.
[0058] The drive sleeve 334 may be secured to a dial sleeve 340 that is rotationally fixed to a scale drum 324. The dial sleeve 340 may extend longitudinally through the housing 302 around the torsion spring 330, such that the torsion spring 330 extends between the drive sleeve 334 and the dial sleeve 340. The dial sleeve 340 may have a plurality of longitudinal splines 342 on an outer surface received in a plurality of longitudinal grooves on an inner surface of the scale drum 324. Thus, the scale drum 324 is rotationally fixed to the dial sleeve 340 but axially movable along the outer surface of the dial sleeve 340. The scale drum 324 may be threaded to an inner surface of the housing 302, for example, by a helical groove 344 in an outer surface of the scale drum 324 receiving a helical protrusion on an inner surface of the housing 302. The scale drum 324 may have indicia formed or printed on the outer surface (as illustrated in FIGS. 1 and 2) in a helically arranged pattern. Thus, rotation of the drive sleeve 334 with the dial member 312 causes rotation of the dial sleeve 340 that in turn causes the scale drum 324 to rotate and translate helically relative to the housing 302. The helical rotation of the scale drum 324 exposes the indicia through a window 316 that indicates the dose set corresponding to the tensioning of the torsion spring 330.
[0059] The injection device 300 may include a dial mechanism configured to enable incremental dose setting while preventing release of the tension in the torsion spring 330 before initiating injection. The dial mechanism may include a clutch ring 350 having a plurality of outer teeth 352 and a plurality of inner teeth 354. The outer teeth 352 may be configured to engage the housing 302 to rotationally fix the clutch ring 350 during dose setting and be disengaged from the housing 302 during dose delivery (as further discussed below). The plurality of inner teeth 354 may be configured to engage one or more pawl arms 356 to resist rotation of the drive sleeve 334. Each of the pawl arms 356 may have a protrusion 358 extending proximally from a free end of the pawl arm 356 and be configured to be received between the inner teeth 354 of the clutch ring 350. The protrusion 358 may be rounded or have a circular profile. The protrusion 358 may strike the clutch ring 350 to generate an audible and/or tactile click for each dose unit being dialed. The protrusion may include a first portion 358a having a first diameter and a second portion 358b having a second diameter extending proximally from the first portion 358a, wherein the first diameter is greater than the second diameter. The first portion 358a of the protrusion 358 may be configured to engage the clutch ring 350.
[0060] The pawl arms 356 may be radially flexible to displace the one or more protrusions 358 from a radial outward position between the inner teeth 354 of the clutch ring 350 (as illustrated in FIG. 14 with the clutch ring 350 transparent) and a radially inward position to pass or ride over the inner teeth 354 of the clutch ring 350 to set a dose. The deflection of the one or more pawl arms 356 may be guided by one or more channels 360 on a distal portion of the dial sleeve 340. Specifically, the second portion 358b of the protrusion 358 may be guided by the one or more channels 360. Each of the channels 360 may include one or more angled segments 361 extending at an angle relative to the circumference of the dial sleeve 340 to guide the protrusion 358 to the radially inward position. For example, each of the channels 360 may have a pair of angled segments 361 extending radially inwardly from a radially outer apex 363, being substantially V-shaped (as illustrated in FIG. 13). In the absence of a rotational force applied by the user, each protrusion 358 may be biased into the radially outward position at the apex 363 of the channel 360 and between the inner teeth 354 of the clutch ring 350. In the radially outward position, the inner teeth 354 of the clutch ring 350 may engage the protrusion 358 to prevent unwinding of the torsion spring 330 when the dial member 312 is not being rotated. When the dial member 312 is rotated by the user, relative rotation between the drive sleeve 334 and the dial sleeve 340 may cause the protrusion 358 to follow the channel 360 to the radially inward position to lift or ride the protrusion 358 over the inner teeth 354 of the clutch ring 350. For example, the protrusion 358 may be rotated in a counterclockwise direction into a first of the angled segments 361 when the user dials up the dose (increasing tension on the torsion spring 330) and in a clockwise direction into a second of the angled segments 361 when the user dials down the dose (decreasing tension on the torsion spring 330). However, it is contemplated that the directions of rotation could be reversed for dial up and dial down. After the dose is set, the natural bias of the pawl arm 356 may apply a radial force to the protrusions 358 to return the protrusion 358 to the radially outward position at the apex of the channel 360 and between the inner teeth 354 of the clutch ring 350. The radial interior of the channels 360 be open (as illustrated in FIG. 13) or be closed by a radial interior surface of the dial sleeve 340 (not shown). The one or more pawl arms 356 may extend from the distal portion of the drive sleeve 334, and the one or more pawl arms 356 may generally follow the circumference of an outer surface of the distal portion of the drive sleeve 334. The inner teeth 354 may be symmetrical or asymmetric (e.g., to provide more resistance in the dial -down direction to retain tension in the torsion spring 330 when asymmetric).
[0061] One or more fixed arms 362 may also extend from the distal portion of the drive sleeve 334. The one or more fixed arms 362 may be positioned radially outside of the drive sleeve 334 and extend proximally. The one or more fixed arms 362 may be configured to stabilize the distal portion of the drive sleeve 334 during rotation via contact with the dial sleeve 340. As further illustrated in FIG. 14, the one or more fixed arms 362 may have an outer radial dimension less than an inner radial dimension of the plurality of inner teeth 354, such that the plurality of fixed arms 362 may approximate or abut the inside of the plurality of inner teeth 354. Each fixed arm 362 may be received in a curved channel 365 that extends substantially parallel to an outer circumference of the dial sleeve 340, as illustrated in FIG. 13. The one or more fixed arms 362 may be rotated without radial deflection and not providing substantial rotational resistance. Each fixed arm 362 may be rotated to a first side of the curved channel 365 when the dial sleeve 340 is rotated in a counterclockwise direction and the one or more protrusions 358 is guided into the first of the angled segments 361. Similarly, each fixed arm 362 may be rotated to a second side of the curved channel 365 when the dial sleeve 340 is rotated in a clockwise direction and the one or more protrusions 358 is guided into the second of the angled segments 361. The fixed arms 362 transfer the rotation of the drive sleeve to the dial sleeve 340 and to the scale drum 324. The endstop faces of the curved channel 365 are positioned such that the fixed arms 362 make contact before, or simultaneously to, the protrusion 358 reaching the end of channel 360. In doing so, the rotational force applied by the user is being transferred from the drive sleeve 334 to the dial sleeve 340 primarily through the fixed arms 362 that are more rigid than the flexible arms 356. Furthermore, the fixed arms 362 transfer the axial movement of the drive sleeve 334 to the clutch 350.
[0062] The dial sleeve 340 may further include one or more retention arms 366 configured to axially secure the dial sleeve 340 to the clutch ring 350. The one or more retention arms 366 may extend distally from the distal portion of the dial sleeve 340 and past the distal portion of the drive sleeve 334. For example, each retention arm 366 may extend through a gap 367 between one of the pawl arms 356 and one of the fixed arms 362, as illustrated in FIG. 12. The retention arms 366 may have a distal protrusion 368 configured to snap over an inner flange 370 of the clutch ring 350. The distal protrusion 368 may engage a distal surface of the inner flange 370 to axially secure the dial sleeve 340 to the clutch ring 350, preventing the clutch ring 350 from being pulled off of the dial sleeve 340.
[0063] Thus, the drive sleeve 334 and the dial sleeve 340 may be rotated relative to each other in small increments (as discussed above). The one or more pawl arms 356, and/or fixed arms 362 may be integrally and/or monolithically formed on the distal portion of the drive sleeve 334. As illustrated in FIG. 12, the drive sleeve 334 may include a plurality of the pawl arms 356 and a plurality of the fixed arms 362 alternating and symmetrically arranged around a longitudinal axis of the drive sleeve 334. The one or more retention arms 366 may be integrally and/or monolithically formed on the distal portion of the dial sleeve 340.
[0064] As illustrated in FIG. 8, the injection device 300 may include a drive mechanism configured to release tension from the torsion spring 330 to deliver the dose of medicament set by the dial mechanism. The drive mechanism may include a threaded piston rod 380, a nut element 382, and a drive element 384. The threaded piston rod 380 may be rotationally received in a threaded opening of the nut element 382 that is rotationally and longitudinally fixed inside of the housing 302. The threaded piston rod 380 may have opposing longitudinal grooves interrupting the thread configured to rotationally fix the threaded piston rod 380 to inner protrusions of the drive element 384. The drive element 384 may be rotationally fixed to the clutch ring 350 and be configured to rotate relative to the housing 302. The drive element 384 may further include a pair of opposed circumferentially extending flexible ratchet arms configured to engage corresponding ratchet teeth on an inner surface of the housing 302 to provide a one-way rotational engagement with the housing 302. The drive element 384 and the clutch ring 350 may be rotationally fixed by cooperating coupling structures that allow the clutch ring 350 to be moved axially relative to the drive element 384. As discussed above, the outer teeth 352 of the clutch ring 350 may be configured to rotationally fix the clutch ring 350 when in a proximal position to the housing 302 that also rotationally fixes the drive element 384 during dose setting.
[0065] The injection may be initiated by a user pressing distally on the button 314. The button 314 may axially engage the drive sleeve 334, while the drive sleeve 334 is configured to rotate relative to the button 314. Thus, the distal pressing of the button 314 causes distal movement of the drive sleeve 334 to disengage the outer teeth 336 of the drive sleeve 334 from the dial member 312 to rotationally disengage the drive sleeve 334 from the dial member 312. A button spring (not shown) may bias the button 314 to a proximal position disengaging the drive mechanism.
[0066] The distal axial displacement of the drive sleeve 334 longitudinally translates the clutch ring 350 relative to the housing 302 to a distal position. In the distal position of the clutch ring 350, the outer teeth 352 are disengaged from the housing 302 to enable rotation of the clutch ring 350 relative to the housing 302. The clutch ring 350 is rotationally fixed to the drive sleeve 334 that is rotationally secured to the dial sleeve 340. Thus, when the clutch ring 350 is moved into the distal position, the torsion spring 330 is free to rotate the drive sleeve 334, the dial sleeve 340, and the clutch ring 350. The clutch ring 350 is rotationally fixed to the drive element 384 that rotates the threaded piston rod 380 through the nut element 382. The threaded engagement of the nut element 382 causes the rotating piston rod 380 to longitudinally translate and push the stopper through the cartridge to expel the medicament. Rotation of the dial sleeve 340 also causes the scale drum 324 to rotate and return to a “zero” position. The torsion spring 330 may still be tensioned in the “zero” position due the torsion spring 330 being preloaded during assembly to deliver both small and large doses within an acceptable speed interval, time interval, or duration.
[0067] As further illustrated in FIG. 8, the injection device 300 may have an end-of-content (EOC) member 386 configured to prevent the user from setting a larger dose than the amount of medicament remaining in the cartridge. The EOC member 386 is threaded over the piston rod 380 and rotationally locked to the drive sleeve 334. The EOC member 386 rotates during dose setting and dose correction as the drive sleeve 334 rotates, and moves axially back and forth following the thread of the piston rod 380. The EOC member 386 is configured to engage a stop at a proximal portion of the piston rod 380. The stop corresponds to an end of the medicament in the cartridge and prevents the dial sleeve 340, the drive sleeve 334, and the dial member 312 from further rotating to increase the dose. The relative position of the EOC member 386 remains stationary during dose delivery because the drive sleeve 334 and the piston rod 380 rotate together.
[0068] FIGS. 15-18 illustrate a third embodiment of an injection device 400 consistent with the disclosure of the injection device 100 as illustrated in FIGS. 1 and 2, the disclosure of which is incorporated herein by reference to describe the injection device 400.
[0069] As further illustrated in FIG. 15, the injection device 400 may have a housing 402 with a proximal skirt portion 426 provided with a circumferential ridge 428 configured to rotationally mount a dial member 412 in a snap coupling. A torsion spring 430 may extend longitudinally through the housing 402. A proximal end of the torsion spring 430 may be fixed relative to the housing 402, for example, by a loop on a proximal end of the torsion spring 430 secured to a proximal ring 432 that is fixed longitudinally and rotationally to the housing 402. A distal end of the torsion spring 430 may be fixed relative to a distal portion of a drive sleeve 434 and/or a dial sleeve 440, for example, by a loop on a distal end of the torsion spring 430 secured to the distal portion of the drive sleeve 434 and/or the dial sleeve 440. In a preferred embodiment, the distal end of the torsion spring 430 may be secured directly to the dial sleeve 440 to facilitate assembly. The drive sleeve 434 may extend longitudinally through the housing 402 inside of the torsion spring 430. The drive sleeve 434 may include a plurality of outer teeth 436 at a proximal portion splined to a plurality of inner teeth or longitudinal grooves (not shown) on the dial member 412. Thus, the drive sleeve 434 may have a proximal position rotationally fixed to the dial member 412 when the injection device 400 is configured to set a dose, such that rotation of the dial member 412 rotates the drive sleeve 434 that in turn rotationally tensions the torsion spring 430.
[0070] The drive sleeve 434 may be secured to a dial sleeve 440 that is rotationally fixed to a scale drum 424. The dial sleeve 440 may extend longitudinally through the housing 402 around the torsion spring 430, such that the torsion spring 430 extends between the drive sleeve 434 and the dial sleeve 440. The dial sleeve 440 may have a plurality of longitudinal splines 442 on an outer surface received in a plurality of longitudinal grooves on an inner surface of the scale drum 424. Thus, the scale drum 424 is rotationally fixed to the dial sleeve 440 but axially movable along the outer surface of the dial sleeve 440. The scale drum 424 may be threaded to an inner surface of the housing 402, for example, by a helical groove 444 in an outer surface of the scale drum 424 receiving a helical protrusion on an inner surface of the housing 402. The scale drum 424 may have indicia formed or printed on the outer surface (as illustrated in FIGS. 1 and 2) in a helically arranged pattern. Thus, rotation of the drive sleeve 434 with the dial member 412 causes rotation of the dial sleeve 440 that in turn causes the scale drum 424 to rotate and translate helically relative to the housing 402. The helical rotation of the scale drum 424 exposes the indicia through a window 416 that indicates the dose set corresponding to the tensioning of the torsion spring 430.
[0071] The injection device 400 may include a dial mechanism configured to enable incremental dose setting while preventing release of the tension in the torsion spring 430 before initiating injection. The dial mechanism may include a clutch ring 450 having a plurality of outer teeth 452 and a plurality of inner teeth 454. The outer teeth 452 may be configured to engage the housing 402 to rotationally fix the clutch ring 450 during dose setting and be disengaged from the housing 402 during dose delivery (as further discussed below). The plurality of inner teeth 454 may be configured to engage one or more pawl beams 456 to resist rotation of the drive sleeve 434. Each of the pawl beams 456 may have a protrusion 458 extending radially and configured to be received between the inner teeth 454 of the clutch ring 450. The protrusion 458 may strike the clutch ring 450 to generate an audible and/or tactile click for each dose unit being dialed.
[0072] Upon rotation of the dial sleeve 440, the one or more pawl beams 456 may be radially flexible to displace the protrusions 458 between a radial outward position between the inner teeth 454 of the clutch ring 450 (as illustrated in FIGS. 15 and 16) and a radially inward position to pass or ride over the inner teeth 454 of the clutch ring 450 in order to set a dose, which includes dialing up or dialing down the dose (e.g., increasing or decreasing tension on the torsion spring 430). Each of the pawl beams 456 may have circumferentially opposing fixed ends attaching the pawl beam 456 to the remainder of the dial sleeve 440. Each of the pawl beams 456 may be defined on a proximal side by a circumferential slot 457 positioned proximally of the pawl beam 456 and extending the circumferential length of the pawl beam 456. Each of the circumferential slots 457 have closed ends and extend only partially along the circumference of the dial sleeve 440. Each of the pawl beams 456 may be defined on a distal side by the open distal end of the dial sleeve 440, such that each of the pawl beams 456 substantially define a portion of the distal end of the dial sleeve 440. However, it is also contemplated that in other embodiments each of the pawl beams 456 may be defined by further circumferential slots positioned distally of the pawl beams 456. The protrusion 458 may be positioned on a central portion of each of the one or more pawl beams 456 between the opposing fixed ends. Thus, the central portion including the protrusion 458 may be configured to deflect inwardly for the dial sleeve 440 to be rotated relative to the clutch ring 450. The inner teeth 454 of the clutch ring 450 may be symmetric, for example forming V- shaped grooves between the inner teeth 454, or asymmetric. As illustrated in FIG. 17, the protrusions 458 may include substantially flat side walls extending from the pawl beam 456 and a rounded radially outer surface configured to engage the grooves between the inner teeth 454. This configuration of the protrusion 458 (e.g., radial length, outer curvature, position on the pawl beam) and/or configuration of the pawl beam 456 (e.g., circumferential length, axial height) may be configured to provide a predetermined force profile for the rotational retention and release of the dial sleeve 440 relative to the clutch ring 450. However, in other embodiments, the protrusion 458 may have a triangular shape complementing or matching the shape of the inner teeth 454 (not shown). The protrusion 458 may, additionally or alternatively, be asymmetrical allowing a differential forces dose setting and dose correction as rotation of the dial sleeve 440 would cause the beam to deflect slightly more or slightly less. The asymmetric shape may provide a stiffer interface (e.g., provided by a surface closer to a right angle) in the dose correction direction to prevent unintentional unwinding of the torsion spring 430.
[0073] The dial sleeve 440 may further include one or more retention arms 466 configured to axially secure the dial sleeve 440 to the clutch ring 450. The retention arms 466 may include an outer flange 472 configured to engage an inner flange 470 of the clutch ring 450 to axially secure the dial sleeve 440 to the clutch ring 450, preventing the clutch ring 450 from being pulled off of the dial sleeve 440. The one or more pawl beams 456 and the retention arms 446 may be on a distal portion 441 of the dial sleeve 440, the distal portion 441 having a reduced diameter to be received in the clutch ring 450. The one or more pawl beams 456 and/or the retention arms 446 may be integrally and/or monolithically formed with the dial sleeve 440. As illustrated in FIG. 17, the dial sleeve 440 may include a plurality of the pawl beams 456 and a plurality of the retention arms 446 alternating and symmetrically arranged around a longitudinal axis of the dial sleeve 440.
[0074] As illustrated in FIG. 18 (with the dial sleeve 440 being transparent), the drive sleeve 434 may be splined to the inside of the dial sleeve 440 to rotationally fix the drive sleeve 434 to the dial sleeve 440. The drive sleeve 434 may include one or more outer protrusions 438, and the dial sleeve 440 may include one or more inner channels 439, where the one or more outer protrusions 438 may be axially slide into the one or more inner channels 439 during assembly to rotationally fix the drive sleeve 443 and the dial sleeve 440. During dose delivery, axial advancement of the drive sleeve 434 may push the dial sleeve 440 distally, via the one or more outer protrusions 438. [0075] As illustrated in FIG. 15, the injection device 400 may include a drive mechanism configured to release tension from the torsion spring 430 to deliver the dose of medicament set by the dial mechanism. The drive mechanism may include a threaded piston rod 480, a nut element 482, and a drive element 484. The threaded piston rod 480 may be rotationally received in a threaded opening of the nut element 482 that is rotationally and longitudinally fixed inside of the housing 402. The threaded piston rod 480 may have opposing longitudinal grooves interrupting the thread configured to rotationally fix the threaded piston rod 480 to inner protrusions of the drive element 484. The drive element 484 may be rotationally fixed to the clutch ring 450 and be configured to rotate relative to the housing 402. The drive element 484 may further include a pair of opposed circumferentially extending flexible ratchet arms configured to engage corresponding ratchet teeth on an inner surface of the housing 402 to provide a one-way rotational engagement with the housing 402. The drive element 484 and the clutch ring 450 may be rotationally fixed by cooperating coupling structures that allow the clutch ring 450 to be moved axially relative to the drive element 484. As discussed above, the outer teeth 452 of the clutch ring 450 may be configured to rotationally fix the clutch ring 450 when in a proximal position to the housing 402 that also rotationally fixes the drive element 484 during dose setting.
[0076] The injection may be initiated by a user pressing distally on the button 414. The button 414 may axially engage the drive sleeve 434, while the drive sleeve 434 is configured to rotate relative to the button 414. Thus, the distal pressing of the button 414 causes distal movement of the drive sleeve 434 to disengage the outer teeth 436 of the drive sleeve 434 from the dial member 412 to rotationally disengage the drive sleeve 434 from the dial member 412. A button spring (not shown) may bias the button 414 to a proximal position disengaging the drive mechanism.
[0077] The distal axial displacement of the drive sleeve 434 longitudinally translates the clutch ring 450 relative to the housing 402 to a distal position. In the distal position of the clutch ring 450, the outer teeth 452 are disengaged from the housing 402 to enable rotation of the clutch ring 450 relative to the housing 402. The clutch ring 450 is rotationally fixed to the dial sleeve 440 that is rotationally fixed to the drive sleeve 434. Thus, when the clutch ring 450 is moved into the distal position, the torsion spring 430 is free to rotate the drive sleeve 434, the dial sleeve 440, and the clutch ring 450. The clutch ring 450 is rotationally fixed to the drive element 484 that rotates the threaded piston rod 480 through the nut element 482. The threaded engagement of the nut element 482 causes the rotating piston rod 480 to longitudinally translate and push the stopper through the cartridge to expel the medicament. Rotation of the dial sleeve 440 also causes the scale drum 424 to rotate and return to a “zero” position. The torsion spring 430 may still be tensioned in the “zero” position due the torsion spring 430 being preloaded during assembly to deliver both small and large doses within an acceptable speed interval, time interval, or duration.
[0078] As further illustrated in FIG. 15, the injection device 400 may have an end-of-content (EOC) member 486 configured to prevent the user from setting a larger dose than the amount of medicament remaining in the cartridge. The EOC member 486 is threaded over the piston rod 480 and rotationally locked to the drive sleeve 434. The EOC member 486 rotates during dose setting and dose correction as the drive sleeve 434 rotates, and moves axially back and forth following the thread of the piston rod 480. The EOC member 486 is configured to engage a stop at a proximal portion of the piston rod 480. The stop corresponds to an end of the medicament in the cartridge and prevents the dial sleeve 440, the drive sleeve 434, and the dial member 412 from further rotating to increase the dose. The relative position of the EOC member 486 remains stationary during dose delivery because the drive sleeve 434 and the piston rod 480 rotate together.
[0079] FIGS. 19-23 illustrate a fourth embodiment of an injection device 500 consistent with the disclosure of the injection device 100 as illustrated in FIGS. 1 and 2, the disclosure of which is incorporated herein by reference to describe the injection device 500.
[0080] As further illustrated in FIG. 19, the injection device 500 may have a housing 502 with a proximal skirt portion 526 provided with a circumferential ridge 528 configured to rotationally mount a dial member 512 in a snap coupling. A torsion spring 530 may extend longitudinally through the housing 502. A proximal end of the torsion spring 530 may be fixed relative to the housing 502, for example, by a loop on a proximal end of the torsion spring 530 secured to a proximal ring 532 that is fixed longitudinally and rotationally to the housing 502. A distal end of the torsion spring 530 may be fixed relative to a distal portion of a drive sleeve 534 and/or a dial sleeve 540, for example, by a loop on a distal end of the torsion spring 530 secured to the distal portion of the drive sleeve 534 and/or a dial sleeve 540. In a preferred embodiment, the distal end of the torsion spring 530 may be secured directly to the dial sleeve 540 to facilitate assembly. The drive sleeve 534 may extend longitudinally through the housing 502 inside of the torsion spring 530. The drive sleeve 534 may include a plurality of outer teeth 536 at a proximal portion splined to a plurality of inner teeth or longitudinal grooves (not shown) on the dial member 512. Thus, the drive sleeve 534 may have a proximal position rotationally fixed to the dial member 512 when the injection device 500 is configured to set a dose, such that rotation of the dial member 512 rotates the drive sleeve 534 that in turn rotationally tensions the torsion spring 530.
[0081] The drive sleeve 534 may be secured to a dial sleeve 540 that is rotationally fixed to a scale drum 524. The dial sleeve 540 may extend longitudinally through the housing 502 around the torsion spring 530, such that the torsion spring 530 extends between the drive sleeve 534 and the dial sleeve 540. The dial sleeve 540 may have a plurality of longitudinal splines 542 on an outer surface received in a plurality of longitudinal grooves on an inner surface of the scale drum 524. Thus, the scale drum 524 is rotationally fixed to the dial sleeve 540 but axially movable along the outer surface of the dial sleeve 540. The scale drum 524 may be threaded to an inner surface of the housing 502, for example, by a helical groove 544 in an outer surface of the scale drum 524 receiving a helical protrusion on an inner surface of the housing 502. The scale drum 524 may have indicia formed or printed on the outer surface (as illustrated in FIGS. 1 and 2) in a helically arranged pattern. Thus, rotation of the drive sleeve 534 with the dial member 512 causes rotation of the dial sleeve 540 that in turn causes the scale drum 524 to rotate and translate helically relative to the housing 502. The helical rotation of the scale drum 524 exposes the indicia through a window 516 that indicates the dose set corresponding to the tensioning of the torsion spring 530.
[0082] The injection device 500 may include a dial mechanism configured to enable incremental dose setting while preventing release of the tension in the torsion spring 530 before initiating injection. The dial mechanism may include a clutch ring 550 having a plurality of outer teeth 552. The outer teeth 552 may be configured to engage the housing 502 to rotationally fix the clutch ring 550 during dose setting and be disengaged from the housing 502 during dose delivery (as further discussed below). The clutch ring 550 may further have a plurality of distal teeth 554 extending proximally from the clutch ring 550, and the dial sleeve 540 may have a plurality of proximal teeth 556 extending distally from the dial sleeve 540. The plurality of distal teeth 554 of the clutch ring 550 may be configured to engage the proximal teeth 556 of the dial sleeve 540 to resist rotation of the drive sleeve 534. The proximal teeth 556 on the dial sleeve 540 may mesh with the distal teeth 554 on the clutch ring 550 in an axial direction to form a dog clutch, and the dial sleeve 540 may be configured to rotate relative to the clutch ring 550 during dose setting. The distal teeth 554 and/or the proximal teeth 556 may strike the opposing component to generate an audible and/or tactile click for each dose unit being dialed.
[0083] A spring 558 may bias the distal teeth 554 of the clutch ring 550 into engagement with the proximal teeth 556 of the dial sleeve 540 with sufficient force to prevent the dial sleeve 540 from unwinding when the dial member 512 is not being rotated. The dial sleeve
540 may have a distal portion 541 having a reduced diameter to extend through the clutch ring 550, the spring 558, and a retention ring 560. The spring 558 may be positioned axially between the clutch ring 550 and the retention ring 560. The spring 558 may be a helical spring. The retention ring 560 may be a separate component assembled to the distal portion
541 of the dial sleeve 540. For example, the retention ring 560 may include one or more radial protrusions 562, and the distal portion 541 may include one or more radial channels 564, such that the one or more radial protrusions 562 snap into the one or more radial channels 564 to secure the retention ring 560 on the distal portion 541 of the dial sleeve 540 during assembly. The engagement of a plurality of the radial protrusions 562 and a plurality of the radial channels 564 may axially and rotationally fix the retention ring 560 to the dial sleeve 540. The retention ring 560 may have a circumferential rim 561 that abuts the spring 558 to bias the distal teeth 554 into engagement with the proximal teeth 556. The circumferential rim 561 may be interrupted by slots that form the plurality of radial protrusions 562, as illustrated in FIG. 21. The retention ring 560 may have an open or closed distal end.
[0084] In operation, the plurality of distal teeth 554 of the clutch ring 550 may be configured to engage the proximal teeth 556 of the dial sleeve 540 to resist rotation of the drive sleeve 534. When the dial member 512 is rotated in one direction (for example, in the counterclockwise direction to dial up the dose by increasing tension on the torsion spring 530), the rotational force can be transferred through the dial sleeve 540 from the proximal teeth 556 of the dial sleeve 540 to the distal teeth 554 of the clutch ring 550. This force causes the clutch ring 550 to translate distally against the counterforce imparted by the spring 558, thus compressing the spring 558 and allowing the proximal teeth 556 ride over the distal teeth 554. As such, the dial sleeve 540 is permitted to rotate relative to the clutch ring 550 to increase a set dose of medicament by increasing tension on the torsion spring 530. Similarly, when the dial member 512 is rotated in the opposite direction (for example, in the clockwise direction to dial down the dose by decreasing tension on the torsion spring), the rotational force can also be transferred through the dial sleeve 540 from the proximal teeth 556 of the dial sleeve 540 to the distal teeth 554 of the clutch ring 550. Though clockwise and counterclockwise rotations are explicitly correlated with dial up and dial down, respectively, it is contemplated that the directions of rotation could be reversed for dose dial up and dial down. This force causes the clutch ring 550 to translate distally against the counterforce imparted by the spring 558, thus compressing the spring 558 and allowing the proximal teeth 556 ride over the distal teeth 554. As such, the dial sleeve 540 is permitted to rotate relative to the clutch ring 550 to decrease a set dose of medicament by decreasing tension on the torsion spring 530. During dose dial up and dial down, the clutch ring 550 is configured to translate distally a first distance that is less than a second distance required to initiate injection, such that the clutch ring 550 remains rotationally fixed to the housing 502 during dose dial up and dial down. Upon each incremental rotation in the dial up and dial down direction, the spring 558 can force the clutch ring 550 proximally so as to engage the distal teeth 554 with the proximal teeth 556. The proximal and distal teeth 556, 554 and/or the spring 558 can be configured so as to require a predetermined rotational force on the dial member 512 to initiate rotation of the dial sleeve 540 in the dial up and dial down direction. In some embodiments, the required force for dialing up the set dose of medicament can be different (e.g., less) than the required force for dialing down the set dose of medicament. [0085] The distal teeth 554 and the proximal teeth 556 may be symmetric or asymmetric. For example, as illustrated in FIG. 23, the distal teeth 554 and the proximal teeth 556 may be asymmetric to provide increased resistance in the dial down direction. The increased resistance may prevent the teeth 554, 556 from unintentionally slipping under the bias of the torsion spring 530. For example, the increased resistance may be provided by each of the teeth 554, 556 having a greater angle relative to the circumference (more axial than) in the clockwise direction than in the counterclockwise direction to prevent the teeth 554, 556 from unintentionally slipping under the bias of the torsion spring 530.
[0086] As illustrated in FIG. 23 (with the dial sleeve 540 being transparent), the drive sleeve 434 may be splined to the inside of the dial sleeve 540 to rotationally fix the drive sleeve 534 to the dial sleeve 540. The drive sleeve 534 may include one or more outer protrusions 538, and the dial sleeve 540 may include one or more inner channels 539, where the one or more outer protrusions 538 may be axially slide into the one or more inner channels 539 during assembly to rotationally fix the drive sleeve 543 and the dial sleeve 540. During dose delivery, axial advancement of the drive sleeve 534 may push the dial sleeve 540 distally, via the one or more outer protrusions 538.
[0087] As illustrated in FIG. 19, the injection device 500 may include a drive mechanism configured to release tension from the torsion spring 530 to deliver the dose of medicament set by the dial mechanism. The drive mechanism may include a threaded piston rod 580, a nut element 582, and a drive element 584. The threaded piston rod 580 may be rotationally received in a threaded opening of the nut element 582 that is rotationally and longitudinally fixed inside of the housing 502. The threaded piston rod 580 may have opposing longitudinal grooves interrupting the thread configured to rotationally fix the threaded piston rod 580 to inner protrusions of the drive element 584. The drive element 584 may be rotationally fixed to the clutch ring 550 and be configured to rotate relative to the housing 502. The drive element 584 may further include a pair of opposed circumferentially extending flexible ratchet arms configured to engage corresponding ratchet teeth on an inner surface of the housing 502 to provide a one-way rotational engagement with the housing 502. The drive element 584 and the clutch ring 550 may be rotationally fixed by cooperating coupling structures that allow the clutch ring 550 to be moved axially relative to the drive element 584. As discussed above, the outer teeth 552 of the clutch ring 550 may be configured to rotationally fix the clutch ring 550 when in a proximal position to the housing 502 that also rotationally fixes the drive element 584 during dose setting.
[0088] The injection may be initiated by a user pressing distally on the button 514. The button 514 may axially engage the drive sleeve 534, while the drive sleeve 534 is configured to rotate relative to the button 514. Thus, the distal pressing of the button 514 causes distal movement of the drive sleeve 534 to disengage the outer teeth 536 of the drive sleeve 534 from the dial member 512 to rotationally disengage the drive sleeve 534 from the dial member 512. A button spring (not shown) may bias the button 514 to a proximal position disengaging the drive mechanism.
[0089] The distal axial displacement of the drive sleeve 534 longitudinally translates the clutch ring 550 relative to the housing 502 to a distal position. In the distal position of the clutch ring 550, the outer teeth 552 are disengaged from the housing 502 to enable rotation of the clutch ring 550 relative to the housing 502. The clutch ring 550 is rotationally fixed to the dial sleeve 540 that is rotationally fixed to the drive sleeve 534. Thus, when the clutch ring 550 is moved into the distal position, the torsion spring 530 is free to rotate the drive sleeve 534, the dial sleeve 540, and the clutch ring 550. The clutch ring 550 is rotationally fixed to the drive element 584 that rotates the threaded piston rod 580 through the nut element 582. The threaded engagement of the nut element 582 causes the rotating piston rod 580 to longitudinally translate and push the stopper through the cartridge to expel the medicament. Rotation of the dial sleeve 540 also causes the scale drum 524 to rotate and return to a “zero” position. The torsion spring 530 may still be tensioned in the “zero” position due the torsion spring 530 being preloaded during assembly to deliver both small and large doses within an acceptable speed interval, time interval, or duration.
[0090] As further illustrated in FIG. 19, the injection device 500 may have an end-of-content (EOC) member 586 configured to prevent the user from setting a larger dose than the amount of medicament remaining in the cartridge. The EOC member 586 is threaded over the piston rod 580 and rotationally locked to the drive sleeve 534. The EOC member 586 rotates during dose setting and dose correction as the drive sleeve 534 rotates, and moves axially back and forth following the thread of the piston rod 580. The EOC member 586 is configured to engage a stop at a proximal portion of the piston rod 580. The stop corresponds to an end of the medicament in the cartridge and prevents the dial sleeve 540, the drive sleeve 534, and the dial member 512 from further rotating to increase the dose. The relative position of the EOC member 586 remains stationary during dose delivery because the drive sleeve 534 and the piston rod 580 rotate together.
[0091] It will be appreciated by persons of ordinary skilled in the art that the present disclosure is not limited by what has been particularly shown and described hereinabove. Rather the scope of the present disclosure includes both combinations and sub-combinations of various features described hereinabove as well as modifications and variations which would occur to persons skilled in the art upon reading the foregoing description.