Patent Description:
Some drug-delivery devices, such as autoinjectors, store potential energy in compression springs which are released at the time of device actuation. This stored energy is used to drive various functions of such drug-delivery devices, such as needle insertion into the patient and ejection of fluid from a drug reservoir. However, long-term potential energy storage in springs can be problematic because resultant forces from compressed springs can cause device material deformation over the shelf life of a device. Furthermore, basic physics and material properties require that springs adequate for storing sufficient potential energy to drive the previously-mentioned functions in a drug-delivery device over the shelf life of the device be of a certain minimum size, which can increase device size. Ideally, springs should remain unstressed or minimally stressed over the shelf life of a device, and then be loaded and released in a relatively short period of time during device use. Prior art is disclosed in <CIT>, <CIT>, <CIT> and <CIT>.

The invention is defined in claims <NUM> and <NUM>. Further aspects and preferred embodiments of the invention are defined in the dependent claims. Any aspects, embodiments and examples of the present disclosure which do fall under the scope of the appended claims are provided for illustrative purposes.

Features and advantages of this disclosure, and the manner of attaining them, will become apparent and will be understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein:.

Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate exemplary embodiments of the invention and such exemplifications are not to be construed as limiting the scope of the invention in any manner.

The present disclosure relates to drug-delivery devices that store energy as a result of work done by the user to perform steps such as needle cartridge indexing, needle insertion, needle retraction, dosing button unlock, fluid path creation from a reservoir to a patient, and pumping.

According to one aspect of the present disclosure, the devices disclosed herein uses work done by a user in a first actuation step (e.g., by pressing a button) to load one or more springs and to index a needle holding cartridge. A second actuation step by the user releases one or more of the loaded springs (e.g., linear compression springs) to drive a needle into a patient's subcutaneous/intramuscular tissue. This step also releases one or more of the loaded springs (e.g., one or more coiled clock springs) to drive a gear train, whose output torque rotates a pump (e.g., a rotary plunger pump). This pump in turn draws fluid from a reservoir and delivers it to the patient. At the end of the dose, further energy from the one or more loaded springs is released to retract the needle and reset the device. An on-body sensing button and associated lock mechanism decreases the chances of the user inadvertently triggering the second actuation step by mechanically locking out the device and preventing the user from triggering the second actuation step until the device is pressed against the patient's body.

The devices disclosed herein may be configured to be filled by a user at the time of use (e.g., in which the user fills the device drug reservoir at the time the device is to be used), assembled at the time of use (e.g., in which a user assembles a pre-filled drug reservoir at the time the device is to be used), or pre-filled and pre-assembled (e.g., in which the device is provided to the user already pre-filled and pre-assembled).

<FIG> is a block diagram providing a system-level overview of an exemplary multi-use drug-delivery device <NUM>, according to some embodiments. Device <NUM> comprises a loading button <NUM>, a dosing button <NUM>, and an optional on-body sensing button <NUM>.

Device <NUM> also comprises a drug reservoir <NUM>. Reservoir <NUM> may be a rigid or elastomeric container configured to store a drug. Device <NUM> may further comprise a drug stored within reservoir <NUM>. In another embodiment, a system may comprise one or more devices including device <NUM> and a drug. The term "drug" refers to one or more therapeutic agents including but not limited to insulins, insulin analogs such as insulin lispro or insulin glargine, insulin derivatives, GLP-<NUM> receptor agonists such as dulaglutide or liraglutide, glucagon, glucagon analogs, glucagon derivatives, gastric inhibitory polypeptide (GIP), GIP analogs, GIP derivatives, oxyntomodulin analogs, oxyntomodulin derivatives, therapeutic antibodies and any therapeutic agent that is capable of delivery by device <NUM>. The drug as used in the device may be formulated with one or more excipients. The device is operated in a manner generally as described herein by a patient, caregiver or healthcare professional to deliver drug to a person.

Device <NUM> also comprises a pump <NUM>. Pump <NUM> may comprise any suitable pump that draws fluid drug from reservoir <NUM> and delivers said fluid drug through a fluid pathway and into the patient's body. One example of a suitable pump <NUM> is a rotary plunger pump. Other examples of suitable pumps include piston pumps, peristaltic pumps, diaphragm pumps, rotary vane pumps, and screw pumps.

Device <NUM> also comprises a needle cartridge <NUM> holding a plurality of needle assemblies. Each individual needle assembly within cartridge <NUM> may comprise an injection needle and a support hub that holds said needle and provides gripping and/or pushing surfaces that allow the needle assembly to be individually handled by an insertion / retraction mechanism. Each needle assembly may be configured to be used for a single injection. After a needle assembly has been used, the needle assembly may be retracted into the needle cartridge <NUM>. After every needle assembly in the cartridge <NUM> has been used, the entire cartridge may be replaced and/or disposed of. In some disposable embodiments of device <NUM>, the entire device <NUM> may be disposed of once every needle in cartridge <NUM> has been used.

Device <NUM> also comprises a needle insertion / retraction mechanism <NUM> that, when actuated by the user, drives an individual needle assembly within cartridge <NUM> that is operationally aligned with mechanism <NUM> from a retracted position into an injection position, and then retracts said individual needle assembly from the injection position back to the retracted position after the injection is complete. Mechanism <NUM> may comprise a single hammer or arm that both drives and retracts the individual needle assembly; alternately, mechanism <NUM> may comprise a plurality of hammers / arms, one/some of which drive the needle assembly, and one/some of which retract the needle assembly. Device <NUM> also comprises a cartridge indexing mechanism <NUM> that, when actuated, advances or indexes cartridge <NUM> to move a spent or used needle assembly out of operational alignment with mechanism <NUM> and positions a new, unused needle assembly into operational alignment with mechanism <NUM>.

Device <NUM> may be used by a user to inject fluid drug stored within reservoir <NUM> into a patient's body. As used herein, a "user" may refer to a person operating device <NUM>, e.g., by pressing its buttons and/or placing the device against the patient's body for an injection. A "patient" may refer to a person receiving the injection. In some embodiments, the "user" and the "patient" may be the same person, e.g., when the device is used by a patient to inject him or herself. In some embodiments, the "user" and the "patient" may be different persons, e.g., when the device is used by a caregiver to inject the patient.

Device <NUM> may be operated by a user by first pressing the loading button <NUM> to "load" the device. When a user presses the loading button <NUM>, the work done by the user in pressing the button <NUM> is captured and/or harvested by an energy transfer, storage, and release mechanism <NUM>. Mechanism <NUM> may comprise one or more mechanical components, such as gears, gear trains, slide racks, pinion couplers, wires, and/or other mechanical linkages, that transfer the work done by the user to other parts of device <NUM>. For example, the work done by the user may be transferred to the cartridge indexing mechanism <NUM> that advances or indexes cartridge <NUM>. Mechanism <NUM> may also comprise one or more springs (e.g., linear springs, torsion springs, clock springs, and the like) that store the work done by the user as potential energy that may be released at a later point in time to drive other parts of device <NUM>.

After the loading button <NUM> has been pressed, the user may trigger the device to initiate an injection by pressing dosing button <NUM>. In some embodiments, however, the dosing button <NUM> is initially locked such that the user cannot depress it. The dosing button <NUM> can be unlocked subsequently, such as, e.g., by a button or another unlocking component. In such embodiments, the user can unlock the dosing button <NUM> by actuating the unlocking button <NUM>. For example, the user may press unlocking button <NUM> with his or her fingers. Alternately, the user may actuate unlocking button <NUM> by pressing the device <NUM> against the patient's body in preparation for an injection (e.g., the unlocking button <NUM> takes the form of an on-body sensing button <NUM>). In such embodiments, when device <NUM> is pressed against the patient's body, the unlocking button <NUM> is depressed, thus unlocking dosing button <NUM>. While the balance of this disclosure refers to an on-body sensing button <NUM>, it should be understood that the that is only one embodiment of device <NUM>. The principal function of button <NUM> is to unlock the dosing button <NUM>, and button <NUM> need not take the form of an on-body sensing button.

When the user subsequently presses the dosing button <NUM>, potential energy stored by the energy transfer, storage, and release mechanism <NUM> (e.g., by one or more springs) is released to drive the needle insertion / retraction mechanism <NUM> to insert an individual needle assembly for an injection. The energy stored by mechanism <NUM> is also released to drive pump <NUM> to pump liquid drug from reservoir <NUM> through the inserted needle assembly and into the patient. In other embodiments, in addition to, or separate from, the driving of the needle assembly, the driven needle assembly may be retracted back into the device after the injection is complete. For example, after the injection is complete, additional energy stored by mechanism <NUM> is released to drive the needle insertion / retraction mechanism <NUM> to retract the inserted needle assembly back into cartridge <NUM>. In some embodiments, no means for converting or storing electrical energy (e.g., batteries, electrical motors) or chemical energy (e.g., fuel cells, combustion engines, fuel storage reservoirs, or reaction chambers for chemical reactions that produce heat or gas) are needed. Instead, all the energy required for driving device <NUM>, including indexing cartridge <NUM>, inserting and retracting a needle, and pumping the drug, are provided by the user.

<FIG> and <FIG> provide a top and a bottom perspective view (respectively) of the external appearance of an exemplary device <NUM>. Solely for ease of explication, <FIG>, <FIG> will use the x, y, z directional system depicted by arrows <NUM>. The symbol ⊙ shall represent an arrow coming out of the page, while the symbol ⊗ shall represent an arrow going into the page. In the specification and claims, references to the "up," "upward," "upper," or "top" direction shall mean the positive z direction; references to the "down," "downward," "lower," or "bottom" direction shall mean the negative z direction; references to the "proximal" direction shall mean the negative x direction; references to the "distal" direction shall mean the positive x direction; references to the "left" direction shall mean the positive y direction; references to the "right" direction shall mean the negative y direction; references to the "horizontal" plane shall mean the x-y plane; and references to the "vertical" plane shall mean the x-z or y-z plane, as appropriate.

Device <NUM> comprises an upper housing <NUM> and a lower housing <NUM> that house the internal components of the device. Loading button <NUM> protrudes from a distal end of the device, dosing button <NUM> protrudes upward from upper housing <NUM>, while on-body sensor button <NUM> (e.g., unlocking button <NUM>) protrudes downward from lower housing <NUM>. Lower housing <NUM> also defines a needle aperture <NUM> (see <FIG>) through which a needle of a needle assembly may protrude when it is inserted into the patient.

<FIG>, <FIG>, and <FIG> display the internal components of device <NUM> when upper housing <NUM> has been removed. <FIG> provides a top-down view of device <NUM>; <FIG> provides a perspective view of device <NUM>; and <FIG> provides an exploded, perspective view of device <NUM>.

In the embodiment depicted in <FIG>, cartridge <NUM> may take the form of a round carousel having a generally planar top surface <NUM> and a generally planar bottom surface <NUM> (see <FIG>). Cartridge <NUM> has a central shaft <NUM> extending through a central, vertical axis of the cartridge from the top surface to the bottom surface. The central shaft <NUM> may be configured to accommodate a central spindle <NUM> that extends vertically upward from the inner surface of lower housing <NUM> (see <FIG>). When central spindle <NUM> is inserted through central shaft <NUM>, carousel <NUM> is configured to rotate about central spindle <NUM>. Carousel <NUM> defines a plurality of cavities 304a, b, c, etc. (collectively or individually referred to herein as a "cavity" or "cavities" <NUM>, as appropriate). Each cavity <NUM> extends radially outward from the central shaft <NUM> towards the radial perimeter of the cartridge and includes an opening in the top surface <NUM> and an opening in the bottom surface <NUM>.

Each cavity <NUM> houses a needle assembly 306a, b, c (collectively or individually referred to herein as a "needle assembly" or "needle assemblies" <NUM>, as appropriate). One exemplary embodiment of a needle assembly <NUM> is depicted in <FIG>. In this embodiment, needle assembly <NUM> comprises a J-shaped needle or cannula <NUM> having a first leg segment <NUM> which is configured to penetrate drug septum <NUM> and draw fluid drug therefrom, as described below, and a second leg segment <NUM> which is configured to be driven into a patient's body to inject the drug. Needle <NUM> is held within a support hub <NUM> having a needle supporting base <NUM>. In addition to holding and supporting needle <NUM>, needle supporting base <NUM> also mounts a ledge <NUM>. Needle supporting base <NUM> also mounts an upstanding arm part <NUM> topped with a tang <NUM>. Additional details regarding cartridge <NUM>, cavities <NUM>, and/or needle assemblies <NUM> are further described in <CIT>, and entitled NEEDLE CARTRIDGE FOR MEDICATION INJECTION DEVICE.

Returning to <FIG>, cartridge <NUM> includes an intermittently rotating drive. For example, cartridge <NUM> comprises a plurality of Geneva wheel members 308a, b, c (collectively or individually referred to herein as a "Geneva wheel member" or "Geneva wheel members" <NUM>, as appropriate) which interact with a Geneva wheel <NUM> to index or advance cartridge <NUM> one increment at a time, as described in further detail below. Each Geneva wheel member comprises a substantially planar member that extends radially outward in the horizontal plane from cartridge <NUM>. Each respective Geneva wheel member may comprise a vertical, concave, arcuate wall <NUM> (see <FIG>) at the furthest extent of such respective wheel member away from central shaft <NUM>. When a Geneva wheel member is aligned with Geneva wheel <NUM>, this vertical, concave wall <NUM> fits against inner hub <NUM> of Geneva wheel <NUM> (see <FIG>). Geneva wheel <NUM> further comprises a Geneva pin <NUM> that extends vertically upward from a horizontal plane of Geneva wheel <NUM>. Every pair of adjacent Geneva wheel members (e.g., 308a and 308b) define a gap in-between said wheel members into which Geneva pin <NUM> may fit.

Reservoir <NUM> (best seen in <FIG>), which in this embodiment takes the form of an elastomeric container, is configured to contain a drug. Reservoir <NUM> may be provided to users pre-filled with drug or may be configured to be filled by users. Pump <NUM> (also best seen in <FIG>) in this embodiment takes the form of a rotary plunger pump. Examples of suitable rotary plunger pumps are disclosed in <CIT>. As discussed in further detail below, pump <NUM> can be driven to pump liquid drug from reservoir <NUM> towards drug septum <NUM>, where it can be pushed into an individual needle and from there into a patient.

Energy transfer, storage, and release mechanism <NUM>, shown in <FIG>, includes a secondary slide <NUM>, a primary slide <NUM>, a latch <NUM>, a dosing button lock <NUM>, a blocker <NUM>, a face gear <NUM>, a gear train comprising gears <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>, and a latch assembly <NUM>. Each of these components shall now be discussed in turn.

Secondary slide <NUM> is attached or mechanically joined via one or more intermediate mechanical components (e.g., gears, rods, wires, or the like) to loading button <NUM>. Slide <NUM> is configured to slidably move parallel to the x-axis of device <NUM> between a secondary slide distal position and a secondary slide proximal position, as described in further detail below. <FIG> provides a more detailed view of one embodiment of secondary slide <NUM>. In this embodiment, secondary slide <NUM> takes the form of a hollow and substantially rectangular-shaped member having its long axis aligned with the x-axis of device <NUM>. Slide <NUM> comprises a first left wall <NUM>, a second right wall <NUM>, a bottom wall <NUM>, a distal wall <NUM>, an open top channel <NUM> defined between body portions of the left and right walls <NUM>, <NUM>, and an open proximal channel <NUM> defined at the proximal end of the slide between ends of the left and right walls <NUM>, <NUM>. Slide <NUM> also comprises a loading button support <NUM> extending from distal wall <NUM>, which is configured to be attached or mechanically joined via one or more intermediate components to loading button <NUM>. Secondary slide <NUM> also comprises a locking tab <NUM> extending horizontally outward from the left wall <NUM> of slide <NUM> and a compression tab <NUM> extending horizontally outward from the right wall <NUM> of slide <NUM>. Secondary slide <NUM> houses a spring <NUM> (see <FIG>) within the channel <NUM>. A distal end of spring <NUM> abuts an interior surface of distal wall <NUM>, and a proximal end of spring <NUM> abuts a tab (not shown) extending downwards from an interior surface of upper housing <NUM>.

<FIG> depicts a perspective view of device <NUM> from a different angle. For simplicity and clarity, certain components have been removed from the view of device <NUM> in <FIG>. As depicted in <FIG>, secondary slide <NUM> also includes one or more slide racks (two shown): a downward-facing slide rack <NUM> and a side-facing slide rack <NUM>. Downward-facing slide rack <NUM> projects horizontally outward from the left wall <NUM> of secondary slide <NUM> (i.e., on the +y side of slide <NUM>) and has teeth that face downwards (i.e., in the -z direction) which interact with gear <NUM> (described in more detail below). Side-facing slide rack <NUM> projects proximally from the proximal end of secondary slide <NUM> (shown coupled to the proximal end portion of the left wall <NUM>) and has teeth that face in the +y direction. The teeth from the side-facing slide rack interact with teeth <NUM> of pinion coupler <NUM>, as described in more detail below.

Returning to <FIG>, primary slide <NUM> is configured to slidably move parallel to the x-axis of device <NUM> between a primary slide distal position and a primary slide proximal position, as described in further detail below. <FIG> provides a more detailed view of one embodiment of primary slide <NUM>. In this embodiment, primary slide <NUM> takes the form of a hollow and substantially rectangular-shaped member that also has its long axis aligned with the x-axis of device <NUM>. Primary slide <NUM> comprises a first left wall <NUM>, a second right wall <NUM>, a bottom wall <NUM>, a distal wall <NUM>, a proximal wall <NUM>, and an open top channel <NUM> defined between the body portions of the left and rights walls <NUM>, <NUM>. Primary slide <NUM> also comprises a locking tab <NUM> extending horizontally outward from the right wall <NUM> of slide <NUM> (i.e., the -y side), and a pair of fins <NUM> that extend proximally from proximal wall <NUM>. Left wall <NUM> and right wall <NUM> define slots <NUM> extending laterally (y-direction) therethrough, and fins <NUM> define channels <NUM> extending laterally (y-direction) therethrough. When device <NUM> is fully assembled (see <FIG>), compression tab <NUM> of secondary slide <NUM> is configured to extend through slots <NUM> and through the interior volume of primary slide <NUM>. Primary slide <NUM> also houses a spring <NUM> within its channel <NUM>. A distal end of spring <NUM> abuts a proximal surface of compression tab <NUM> of secondary slide <NUM>, and a proximal end of spring <NUM> abuts an interior surface of proximal wall <NUM> of primary slide <NUM>.

Latch <NUM> is configured to rotate in the horizontal plane around axis <NUM> and comprises a latch tab <NUM>. When latch <NUM> is rotated in a counter-clockwise direction (when viewed from the top down), an anti-over-rotation mechanism (shown as a spring <NUM>) prevents latch <NUM> from over-rotating and also biases latch <NUM> in a clockwise direction back to its neutral position (i.e., as shown in <FIG>), where a long axis of latch <NUM> is parallel to the x-axis of device <NUM>. The anti-over-rotation mechanism may also include a pin or plate with a spring configured to function as described above.

Dosing button lock <NUM> interacts with other components to prevent the depressing of dosing button <NUM> by the user until the on-body sensing button <NUM> is depressed. Dosing button lock <NUM> is depicted in greater detail in <FIG>. In this embodiment, lock <NUM> comprises a vertical panel <NUM> that defines a pin slot <NUM>. Slot <NUM> may extend diagonally in a +x/+z direction. Lock <NUM> also comprises a horizontal panel <NUM> extending from the vertical panel <NUM>, such as, for example, in an orthogonal manner. Horizontal panel <NUM> defines another pin slot <NUM>, which extends in a +x direction. Horizontal panel <NUM> also comprises a blocker member <NUM>, which takes the form of a substantially flat tab aligned with the horizontal plane, extending from a distal end of horizontal panel <NUM> beyond the vertical panel <NUM>. Member <NUM> is also shown extending laterally beyond the vertical panel <NUM> in the -y direction.

<FIG> provides a cross-sectional, perspective view of device <NUM> when cut along plane <NUM>-<NUM> (see <FIG>), and best depicts how dosing button lock <NUM> interacts with on-body sensing button <NUM> when device <NUM> is fully assembled. For clarity, lower housing <NUM> has been rendered transparent. On-body sensing button <NUM> can translate up and down into or out of a sensing button cavity <NUM>, which is defined within lower housing <NUM>. Button <NUM> also comprises a vertical sensing button shaft <NUM> and around which is coaxially surrounded by a sensing button spring <NUM>. A top end of spring <NUM> abuts an interior surface of cavity <NUM>, while a bottom end of spring <NUM> abuts an interior, top surface of button <NUM>. Spring <NUM> biases button <NUM> downward out of cavity <NUM>. When the user presses the bottom side of device <NUM> against his/her body, the user's pressing force overcomes the biasing force of spring <NUM> and causes button <NUM> to translate upward into cavity <NUM>. When the pressing force is removed, the spring force allows the button <NUM> to return to its biased-out position. A pin <NUM> is configured to extend in a horizontal direction from the left side of shaft <NUM>. When device <NUM> is assembled, pin <NUM> is configured to ride within pin slot <NUM> of dosing button lock <NUM>. As discussed in further detail below, the interaction of pin <NUM> with pin slot <NUM> of dosing button lock <NUM> causes dosing button lock <NUM> to translate proximally (i.e., in the -x direction) when button <NUM> is pushed upward into cavity <NUM>.

Returning to <FIG>, blocker <NUM> interacts with dosing button lock <NUM> to prevent the user from depressing dosing button <NUM> until it has been unlocked, i.e., until the on-body sensing button <NUM> is depressed. When the dosing button <NUM> is unlocked and depressed, blocker <NUM> also interacts with latch assembly <NUM> (described in further detail below) to release energy stored by mechanism <NUM>. Blocker <NUM> is depicted in greater detail in <FIG>. In this embodiment, blocker <NUM> comprises three parts: a blocking tab <NUM>, a button seat <NUM>, and an arm <NUM>. Button seat <NUM> takes the form of a substantially planar surface or member (in this embodiment, having the shape of a circle, but other shapes are also possible) oriented parallel to the horizontal plane of device <NUM>. Blocking tab <NUM> is attached to the left side (i.e., the +y side) of button seat <NUM> and takes the form of a substantially planar surface or member oriented parallel to the vertical plane of device <NUM> that extends in both of the +y/+z directions away from the seat <NUM>. Arm <NUM> is also attached to button seat <NUM>, circumferentially spaced away from the tab <NUM>, extending approximately in the +x direction. Arm <NUM> comprises a fin <NUM> disposed on a distal end thereof, extending in the +y direction. Fin <NUM> comprises a top surface <NUM>, a bottom surface <NUM>, a proximal surface <NUM>, and a distal surface <NUM>. As best seen in <FIG>, top surface <NUM> and bottom surface <NUM> are angled diagonally; that is, they are parallel to a plane oriented in a -x/+z direction.

<FIG> provides a perspective, cross-sectional view of device <NUM> when cut along plane <NUM>-<NUM> (see <FIG>). Both <FIG> and <FIG> best depict how blocker <NUM> interacts with dosing button <NUM> and with dosing button lock <NUM> when device <NUM> is fully assembled. As depicted in <FIG>, when the user has not yet depressed the on-body sensing button <NUM>, blocker member <NUM> of dosing button lock <NUM> is disposed beneath button seat <NUM> of blocker <NUM>. The position of blocker member <NUM> beneath button seat <NUM> of blocker <NUM> prevents blocker <NUM> from translating downwards. As discussed in further detail below, when the user presses the on-body sensing button <NUM> upwards, the interaction between pin <NUM> and pin slot <NUM> of dosing button lock <NUM> causes dosing button lock <NUM> to translate in a proximal direction (i.e., in the -x direction) such that blocker member <NUM> clears button seat <NUM>, thus unlocking blocker <NUM> and allowing blocker <NUM> to translate downwards.

Dosing button <NUM> can translate up and down into or out of a dosing button cavity <NUM>, which is defined within upper housing <NUM> (see <FIG>). Dosing button <NUM> comprises a vertical dosing button shaft <NUM> which is coupled with blocker <NUM> such that button <NUM> and blocker <NUM> translate up and down together. In the embodiment depicted in <FIG>, dosing button shaft <NUM> is coupled with blocker <NUM> using a screw, though any suitable method of fixed attachment may be used (e.g., heat staking, one-way snaps, etc.). A dosing button spring <NUM> coaxially surrounds dosing button shaft <NUM>. A top end of spring <NUM> abuts a bottom surface of button <NUM>, while a bottom end of spring <NUM> abuts an interior, upward-facing surface of dosing button cavity <NUM>. Spring <NUM> biases button <NUM> (and blocker <NUM>, which is attached to button <NUM>) upwards. When a user presses down on button <NUM>, shaft <NUM> transmits the user's downward pressing force of button <NUM> to button seat <NUM> of blocker <NUM>. When blocker <NUM> is unlocked as described previously, the user's downward pressing force causes button <NUM> and blocker <NUM> (including button seat <NUM>) to translate downward.

Mechanism <NUM> also comprises face gear <NUM> and a gear train comprising gears <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>, each of which are best seen in <FIG>. Face gear <NUM> takes the form of a circular-shaped gear that includes a plurality of upward-facing teeth <NUM>. Face gear <NUM> is coupled to a clock spring <NUM>. Both face gear <NUM> and clock spring <NUM> are disposed parallel to the horizontal plane and are configured to rotate about a central axis <NUM>. Clock spring <NUM> resists rotational movement of face gear <NUM> around central axis <NUM>. Put another way, rotating face gear <NUM> around central axis <NUM> in a first rotational direction adds tension to clock spring <NUM>, thus storing potential energy within clock spring <NUM>. Face gear <NUM> interacts with and drives gear <NUM>, which in turn interacts with and drives gear <NUM>. Gear <NUM> also interacts and drives small gear <NUM> which is rotationally coupled with gear <NUM> such that gears <NUM> and <NUM> rotate together. Gear <NUM> in turn interacts with gear <NUM>, which provides rotational torque to pump <NUM>. The number of gears, relative sizes of gears and teeth, and configuration may be selected to provide the rotational speed and torque needed to drive the pump.

<FIG> and <FIG> provide additional, more detailed views of face gear <NUM> and clock spring <NUM>, and how they interact with latch <NUM>. <FIG> provides a top perspective view in which certain components (e.g., slides <NUM>, <NUM>, blocker <NUM>, dosing button lock <NUM>, and latch assembly <NUM>) have been removed to expose face gear <NUM> and clock spring <NUM>, and <FIG> provides a bottom perspective view in which bottom housing <NUM> has been rendered transparent to better view the underside of face gear <NUM>. As can be seen in <FIG>, the top surface of face gear <NUM> defines a plurality of notches 270a, b, c, d, e (collectively or individually referred to herein as "notch" or "notches" <NUM>, as appropriate). While the embodiment of face gear <NUM> depicted in <FIG> defines five notches (notch 270c is obscured beneath gear <NUM> in <FIG>), other embodiments are also possible in which face gear <NUM> defines fewer or more notches. Notches are shown spaced radially from one another and may be spaced equi-radially. Each notch is shaped to accommodate a pawl <NUM>, as described in further detail below in reference to <FIG>. As best seen in <FIG>, face gear <NUM> also comprises a plurality of fins 272a, b, c, d, e (collectively or individually referred to herein as "fins" or "fin" <NUM>, as appropriate). Once again, while the embodiment of face gear <NUM> depicted in <FIG> and <FIG> comprises five fins, other embodiments are also possible in which face gear <NUM> comprises fewer or more fins. Fins are shown spaced radially from one another and may be spaced equi-radially. Each fin extends radially outward in the horizontal plane from the outer circumference of face gear <NUM> and comprises a sloped leading edge and a trailing straight edge. As shown, the fins may be radially offset from the notches. Also as best seen in <FIG>, latch <NUM> further comprises a downward-extending arm <NUM> that extends down from the horizontal plane of latch tab <NUM> to the horizontal plane of face gear <NUM>. Each fin <NUM> is sized and placed such that they will push against and displace arm <NUM> radially outward when face gear <NUM> rotates to a position in which such fin <NUM> is aligned with arm <NUM>, as discussed in further detail below.

Latch assembly <NUM> is visible in the distal-right corner of device <NUM> in <FIG> and depicted in greater detail in <FIG>. Latch assembly comprises a latch support <NUM> that secures latch assembly <NUM> to bottom housing <NUM>. Latch support <NUM> has a first end <NUM> and a second end <NUM>. First end <NUM> of support <NUM> is attached to an interior surface of bottom housing <NUM>, while second end <NUM> of support <NUM> supports a latch pin <NUM> and a pawl <NUM>. Both latch pin <NUM> and pawl <NUM> may rotate in the horizontal plane about axis <NUM>. A torsion v-spring <NUM> is disposed between latch pin <NUM> and pawl <NUM> and coupled to both components such that rotation of latch pin <NUM> around axis <NUM> also imparts rotational forces on pawl <NUM>, and vice versa. When device <NUM> is fully assembled, latch pin <NUM> is configured to interact with fin <NUM> of blocker <NUM> and pawl <NUM> is configured to interact with face gear <NUM>, as described in further detail below.

Cartridge indexing mechanism <NUM> is depicted in <FIG>. Mechanism <NUM> includes a pinion coupler <NUM> having teeth <NUM> that interact and are driven to rotate with teeth of side-facing slide rack <NUM> when rack <NUM> is linearly translated. Pinion coupler <NUM> is rotationally coupled with Geneva wheel <NUM> such that rotation of pinion coupler <NUM> drives rotation of Geneva wheel <NUM>. Geneva wheel <NUM> may be shaped as a substantially planar disc having a first circumference, and an inner hub <NUM> having a second circumference smaller than the first circumference stacked on top of said planar disc. A Geneva pin <NUM> extends vertically upwards from a top surface of the planar disc. Geneva pin <NUM> interacts with Geneva wheel members <NUM> of cartridge <NUM> by fitting in the gaps between adjacent wheel members, as best seen in <FIG>.

Needle insertion / retraction mechanism <NUM> is depicted in <FIG> and in <FIG>. Mechanism <NUM> comprises a drive member or hammer <NUM>. A proximal end of hammer <NUM> includes a head <NUM> which interacts with needle assemblies <NUM> within cartridge <NUM> that are operationally aligned to engage with hammer <NUM>, as discussed in further detail below. A distal end of hammer <NUM> includes pins <NUM> and <NUM> (see <FIG>). When device <NUM> is fully assembled, hammer <NUM> is configured to rotate about pin <NUM>, which is secured to either upper housing <NUM> or lower housing <NUM> (not shown in <FIG>). When device <NUM> is assembled, pin <NUM> of hammer <NUM> is also configured to slot into channel <NUM> defined within fins <NUM> of primary slide <NUM> (see <FIG>). Proximal or distal translation of primary slide <NUM> therefore exerts a force on pin <NUM> of hammer <NUM>, thus causing hammer <NUM> to rotate about pin <NUM>.

The operation of device <NUM> will now be described. <FIG> depict a series of states of device <NUM> in operation, according to some embodiments. <FIG> depicts device <NUM> in an initial neutral state, before the user begins depressing loading button <NUM>. While in this neutral state, spring <NUM> of secondary slide <NUM> biases slide <NUM> in the distal direction to hit a stop (e.g., a surface of secondary slide <NUM> hits a stop in the upper housing <NUM> or lower housing <NUM>, or when a distal surface of compression tab <NUM> hits distal wall <NUM> of primary slide <NUM>). The position of secondary slide <NUM> in this initial neutral state of device <NUM> is referred to herein as the secondary slide distal position. Similarly, while in this neutral state, spring <NUM> of primary slide <NUM> biases slide <NUM> in the distal direction until it hits a stop in the upper housing <NUM> or lower housing <NUM> (not shown). The position of primary slide <NUM> in this initial neutral state of device <NUM> is referred to herein as the primary slide distal position. Geneva pin <NUM> is initially engaged between two Geneva wheel members <NUM> of cartridge <NUM>, labeled 308a and 308b in <FIG>.

<FIG> depicts what happens when a user begins to apply a force in the proximal direction on loading button <NUM>, as depicted by arrow <NUM>. Movement of loading button <NUM> in the proximal direction causes secondary slide <NUM> to translate in the proximal direction parallel to the x-axis of device <NUM>, thus compressing spring <NUM> against the tab (not shown) extending downwards from the interior surface of upper housing <NUM>. Compression tab <NUM> of secondary slide <NUM> also translates in the proximal direction within primary slide <NUM>, thus compressing spring <NUM> against the interior surface of proximal wall <NUM> of primary slide <NUM>. In this way, movement of secondary slide <NUM> in the proximal direction compresses both spring <NUM> and spring <NUM>. As secondary slide <NUM> translates in the proximal direction, locking tab <NUM> eventually pushes against latch tab <NUM> of latch <NUM>. Both locking tab <NUM> and latch tab <NUM> comprise sloped surfaces that, when pushed together, causes latch <NUM> to rotate counter-clockwise (when viewed from the top down) about axis <NUM>, as shown by arrow <NUM> in <FIG>. Eventually, as secondary slide <NUM> continues to translate proximally, locking tab <NUM> clears latch tab <NUM>, at which point latch <NUM> rotates clockwise (when viewed from the top down) about axis <NUM>, as shown by arrow <NUM> in <FIG>, due to the biasing pressure of spring <NUM>. As depicted in <FIG>, latch tab <NUM> slides into place behind (i.e., distal to) locking tab <NUM>, thus preventing secondary slide <NUM> from translating distally. The position of secondary slide <NUM> depicted in <FIG> is referred to herein as the secondary slide proximal position.

Proximal movement of secondary slide <NUM> also causes side-facing slide rack <NUM> to translate in the proximal direction, as shown by arrow <NUM> in <FIG>. Due to the engagement between the teeth of side-facing slide rack <NUM> and teeth <NUM> of pinion coupler <NUM>, proximal movement of side-facing slide rack <NUM> causes pinion coupler <NUM> to rotate in the clockwise direction (when viewed from the top down), as shown by arrow <NUM>. Due to the rotational coupling between pinion coupler <NUM> and Geneva wheel <NUM>, Geneva wheel <NUM> also rotates in the direction of arrow <NUM>. Rotation of Geneva wheel <NUM> causes Geneva pin <NUM> to disengage from the gap between the two Geneva wheel members 308a, 308b to which pin <NUM> was initially engaged, as shown in <FIG>. As Geneva wheel <NUM> continues to rotate, pin <NUM> re-engages with the next gap defined between two Geneva wheel members (308b, 308c) on cartridge <NUM> in the clockwise direction, as shown in <FIG>. This disengagement and re-engagement of pin <NUM> within the next gap between Geneva wheel members allows cartridge <NUM> to advance or index one increment in the counter-clockwise direction (when viewed from the top down), as depicted by arrow <NUM>. When the pin <NUM> is in re-engagement, the pin <NUM> maintain its position so that the cartridge does not rotate, and the Geneva wheel <NUM> is inhibited from further rotation as there is disengagement of side-facing rack <NUM> from teeth <NUM>, which is depicted in <FIG>.

By the end of the sequence of states depicted by <FIG>, work done by the user in pressing loading button <NUM> has been converted into potential energy stored in the compressed springs <NUM> and <NUM>. This potential energy is prevented from being released by latch tab <NUM>, which prevents secondary slide <NUM> from translating distally and releasing the springs. This potential energy is also prevented from being released by blocker <NUM>, which prevents primary slide <NUM> from translating proximally (as described below). The work done by the user has also been used to index or advance the cartridge <NUM> by one increment, thus moving one spent or used needle assembly out of operational alignment with drive member or hammer <NUM>, and placing a new, unused needle assembly into operational alignment with hammer <NUM>.

<FIG> show the proximal movement of secondary slide <NUM> caused by depression of loading button <NUM> from the +y side of device <NUM>. <FIG> shows the state of device <NUM> in its neutral state, before loading button <NUM> is pressed. <FIG> depicts the proximal movement of button <NUM> as the user depresses it, as shown by arrow <NUM>. Proximal movement of button <NUM> causes secondary slide <NUM> to translate proximally, which in turn causes downward-facing slide rack <NUM> to also translate proximally (since slide rack <NUM> is mounted to secondary slide <NUM>). Due to the engagement between the downward-facing teeth of downward-facing slide rack <NUM> and gear <NUM>, proximal movement of downward-facing slide rack <NUM> causes gear <NUM> to rotate in the direction indicated by arrow <NUM>.

<FIG> show the results of rotating gear <NUM> in the direction of arrow <NUM>. For clarity, certain components (e.g., primary slide <NUM> and drug reservoir <NUM>) have not been depicted to better show the movement of other components. Due to the engagement between gears <NUM> and <NUM>, rotational movement of gear <NUM> in the direction of arrow <NUM> causes gear <NUM> to rotate in the direction of arrow <NUM>. Rotation of gear <NUM> in the direction of arrow <NUM> in turn drives face gear <NUM> to rotate in the direction of arrow <NUM>. As face gear <NUM> is rotated in the direction of arrow <NUM>, tension is added to clock spring <NUM>. As previously discussed, face gear <NUM> defines a plurality of notches <NUM> on the top surface thereof. As face gear <NUM> rotates in the direction of arrow <NUM>, one of these notches <NUM> eventually aligns with pawl <NUM> of latch assembly <NUM>. When this alignment occurs, pawl <NUM> slides into notch <NUM> under the biasing pressure of torsion v-spring <NUM>, thus preventing face gear <NUM> from rotating counter to the direction indicated by arrow <NUM>.

By the end of the sequence of states depicted by <FIG> and <FIG>, the work done by the user in pressing loading button <NUM> has also been converted into potential energy stored in the rotational tension of clock spring <NUM>. This potential energy is prevented from being released by pawl <NUM>, which interacts with one of the notches <NUM> of face gear <NUM> to prevent face gear <NUM> and clock spring <NUM> from unwinding.

After cartridge <NUM> has been advanced one increment (as described above in <FIG>) and after face gear <NUM> has been rotated and locked (as described above in <FIG> and <FIG>), side-facing slide rack <NUM> may be disengaged from teeth <NUM> of pinion coupler <NUM>, and downward-facing slide rack <NUM> may be disengaged from gear <NUM>. Disengagement of side-facing rack <NUM> from teeth <NUM> is depicted in <FIG>, which depict a top-down view of device <NUM>. For clarity, secondary slide <NUM> has been rendered transparent using dashed lines in order to reveal the components underneath it. As apparent from this view, both side-facing slide rack <NUM> and downward-facing slide rack <NUM> are mounted to a common slide rack platform <NUM>. Slide rack platform <NUM> is a substantially planar structure that lies in the horizontal plane of device <NUM> and is in turn mounted below secondary slide <NUM>. Platform <NUM> defines two slide rack slots 245a, 245b which extend diagonally in the +x/+y direction in the horizontal plane. Two underside pins 274a, 274b extending downward from the bottom wall <NUM> of secondary slide <NUM> fit into the slide rack slots 245a, 245b, respectively.

<FIG> depicts an initial, neutral state of device <NUM> in which secondary slide <NUM> is positioned at its furthest distal extent (i.e., in the secondary slide distal position such as in <FIG>). In <FIG>, secondary slide <NUM> translates proximally in the direction of arrow <NUM> in response to the user depressing loading button <NUM>, as previously described. As secondary slide <NUM> translates proximally, underside pins 274a, 274b engage the proximal edges of slide rack slots 245a, 245b, thus causing platform <NUM>, downward-facing slide rack <NUM>, and side-facing slide rack <NUM> to also translate proximally. When secondary slide <NUM> completes its proximal translation, platform <NUM> may continue to slide in the proximal direction such that underside pins 274a, 274b now engage the distal edges of slide rack slots 245a, 245b, as shown in <FIG>. Since slide rack slots 245a, 245b extend diagonally in the +x/+y direction, this continued proximal translation of platform <NUM> in the -x direction causes platform <NUM> to also translate in the -y direction, as illustrated by arrow <NUM>, radially away from the pinion coupler <NUM>. This translation in the -y direction causes the teeth of side-facing slide rack <NUM> to disengage from teeth <NUM> of pinion coupler <NUM>.

<FIG> depict the same sequence of states of device <NUM> from a different angle, and best illustrates how downward-facing slide rack <NUM> disengages from gear <NUM>. Similar to <FIG>, <FIG> depicts the initial neutral state of device <NUM>. <FIG> shows how the downward-facing slide rack <NUM> translates proximally (in the -x direction, as indicated by arrow <NUM>) in response to the user depressing loading button <NUM>, as previously described. When platform <NUM> translates in the -x/-y direction, as previously described and illustrated in <FIG>, downward-facing slide rack <NUM> also translates in the -x/-y direction, as shown by arrow <NUM> in <FIG>. This causes the teeth of downward-facing slide rack <NUM> to disengage from the teeth of gear <NUM>.

After device <NUM> has been loaded by pressing loading button <NUM> and slide racks <NUM>, <NUM> have been disengaged from gear <NUM> and pinion coupler <NUM>, respectively, device <NUM> is ready to be placed onto the patient's body for an injection. <FIG> shows the configuration of device <NUM> after it has been loaded, but before it has been pressed against the patient's body. In this configuration, blocker member <NUM> of dosing button lock <NUM> is positioned underneath blocker <NUM>, thus preventing blocker <NUM> from translating downwards. This prevents the user from triggering device <NUM> prematurely. <FIG> depicts what happens when the user presses device <NUM> against the patient's body. Pressing device <NUM> against the patient's body exerts an upward force on the on-body sensing button <NUM>, which overcomes the downward biasing pressure of sensing button spring <NUM> and causes button <NUM> to translate upwards into sensing button cavity <NUM> in the direction of arrow <NUM>. As on-body sensing button <NUM> translates upwards, pin <NUM> rides within pin slot <NUM> of dosing button lock <NUM>, as previously described. Since pin slot <NUM> in vertical panel <NUM> extends diagonally in the +x/+z direction, the movement of pin <NUM> upwards within pin slot <NUM> also causes dosing button lock <NUM> to translate in the proximal direction (i.e., in the -x direction), as illustrated by arrow <NUM>. As dosing button lock <NUM> translates proximally, blocker member <NUM> clears blocker <NUM>, thus allowing blocker <NUM> to translate downwards (i.e., in the direction of arrow <NUM>). This unlocks dosing button <NUM>, thus readying device <NUM> for an injection.

<FIG> depicts the configuration of device <NUM> after it has been pressed against the patient's body (thus unlocking dosing button <NUM>), but before the dosing button <NUM> has been depressed. In this state, blocking tab <NUM> of blocker <NUM> is positioned in front of locking tab <NUM> of primary slide <NUM>, thus preventing primary slide <NUM> from translating proximally in the -x direction. As previously discussed, this position of primary slide <NUM> is referred to herein as the primary slide distal position. <FIG> depicts what happens when the user depresses dosing button <NUM>. As dosing button <NUM> is depressed downward in the direction of arrow <NUM>, the downward force provided by the user overcomes the upward biasing pressure of dosing button spring <NUM> and causes button <NUM> to translate downwards. The downward force on button <NUM> is transmitted to blocker <NUM> via dosing button shaft <NUM>. This causes blocker <NUM> to also translate downwards in the direction of arrow <NUM>. As blocker <NUM> translates downwards, blocking tab <NUM> clears the locking tab <NUM> of primary slide <NUM>, thus allowing primary slide <NUM> to translate proximally in the direction of arrow <NUM> (i.e., in the -x direction). Since spring <NUM> has been previously compressed by proximal movement of compression tab <NUM> of secondary slide <NUM> (as previously described), primary slide <NUM> is propelled proximally by the loaded spring <NUM> once blocking tab <NUM> clears locking tab <NUM>. The position of primary slide <NUM> when it has translated to its maximum proximal extent is referred to herein as the primary slide proximal position.

<FIG> provide profile views of device <NUM> showing how proximal movement of primary slide <NUM> drives a needle assembly <NUM> within cartridge <NUM> from a retracted position to an injection position. <FIG> shows the configuration of device <NUM> before the user presses dosing button <NUM>. In this state, needle assembly <NUM> is disposed in a retracted position within cavity <NUM> of cartridge <NUM>. When primary slide <NUM> is propelled forward by spring <NUM>, primary slide <NUM> exerts a proximal force in the direction of arrow <NUM> on pin <NUM> of hammer <NUM>. This proximal force causes hammer <NUM> to rotate around pin <NUM> in the direction of arrow <NUM>. As hammer <NUM> rotates in the direction of arrow <NUM>, hammer head <NUM> pushes down on ledge <NUM> of a needle assembly <NUM> within cartridge <NUM> that is in operational alignment with hammer <NUM>, thus driving that needle assembly downwards in the direction of arrow <NUM> to an injection position, as shown in <FIG>. As needle assembly <NUM> translates downwards, first leg segment <NUM> of needle <NUM> penetrates drug septum <NUM>, while second leg segment <NUM> of needle <NUM> projects downward out of needle aperture <NUM> in lower housing <NUM>, punctures the patient's skin and into the patient's body. In this way, when needle assembly <NUM> is in its injection position, needle <NUM> establishes a fluid path from drug septum <NUM> into the patient's body. When the needle assembly is disposed in the injection position, the biasing force of spring <NUM> biases primary slide <NUM> in the proximal direction, thus causing hammer head <NUM> to maintain downward pressure on ledge <NUM> until the needle assembly is retracted (as described below). This ensures the needle assembly maintains its proper depth within the patient's body and in the drug septum <NUM>.

In addition to unlocking primary slide <NUM>, downward translation of blocker <NUM> also drives latch assembly <NUM> to unlock face gear <NUM>. The interaction between blocker <NUM> and latch assembly <NUM> is best depicted in <FIG> shows the spatial position of blocker <NUM> relative to latch assembly <NUM> before the user presses down on dosing button <NUM>. In this initial position, fin <NUM> of blocker <NUM> is positioned just above latch pin <NUM> of latch assembly <NUM>. As blocker <NUM> is driven downwards when the user depresses button <NUM>, bottom surface <NUM> of fin <NUM> contacts latch pin <NUM>. Since bottom surface <NUM> is angled diagonally in a -x/+z direction, downward movement of bottom surface <NUM> causes pin <NUM> to rotate horizontally in the direction indicated by arrow <NUM> around axis <NUM> (see <FIG>). As pin <NUM> rotates in the direction of arrow <NUM>, torsion v-spring <NUM> transmits rotational torque on pawl <NUM> in the direction of arrow <NUM> (again around axis <NUM>).

<FIG> show the interaction between blocker <NUM> and latch assembly <NUM> from another angle. <FIG> shows the state of device <NUM> after the user has loaded the device by depressing loading button <NUM>, but before the user has depressed button <NUM>. In this state, work done by the user in depressing loading button <NUM> is stored in the form of potential energy within coiled clock spring <NUM>, which is coupled to face gear <NUM>. However, face gear <NUM> and clock spring <NUM> are prevented from unwinding by pawl <NUM>, which fits within one of the notches <NUM> defined on face gear <NUM>. As the user depresses dosing button <NUM>, button <NUM> translates downward in the direction of arrow <NUM>. This downward force on button <NUM> causes blocker <NUM> to also translate downward and, as previously discussed, causes latch pin <NUM> to rotate in the direction of arrow <NUM>, and pawl <NUM> to rotate in the direction of arrow <NUM>. Rotation of pawl <NUM> in the direction of arrow <NUM> causes pawl <NUM> to disengage from notch <NUM>, thus allowing face gear <NUM> and clock spring <NUM> to unwind in the direction of arrow <NUM>, as depicted in <FIG>.

Referring back to <FIG>, as the user continues to push downward on loading button <NUM>, and as blocker <NUM> continues to translate downward, latch pin <NUM> eventually leaves contact with bottom surface <NUM> of fin <NUM>, and instead contacts proximal surface <NUM> of fin <NUM>. At this point, latch pin <NUM> stops rotating in the direction of arrow <NUM>. As blocker <NUM> continues to translate downward, latch pin <NUM> clears proximal surface <NUM> as the entire fin <NUM> slips underneath latch pin <NUM>. When the user stops pushing downward on button <NUM>, button <NUM> and blocker <NUM> rise upward again due to the biasing pressure of dosing button spring <NUM>. At this point, latch pin <NUM> contacts top surface <NUM> of fin <NUM>. Since top surface <NUM> of fin <NUM> is also angled diagonally in a -x/+z direction, top surface <NUM> now forces latch pin <NUM> to rotate in the opposite direction around axis <NUM>, i.e., in the direction of arrow <NUM>. As pin <NUM> rotates in the direction of arrow <NUM>, torsion v-spring transmits rotational torque on pawl <NUM> in the direction of arrow <NUM>.

<FIG> provide a view of device <NUM> from below, in which lower housing <NUM> has been rendered transparent to better show how the unwinding of face gear <NUM> unlatches latch <NUM>. <FIG> depicts device <NUM> after pawl <NUM> has been disengaged from one of the notches <NUM> in face gear <NUM> and face gear <NUM> and clock spring <NUM> begin unwinding in the direction of arrow <NUM>. While face gear <NUM> and clock gear <NUM> are unwinding, the needle insertion / retraction mechanism <NUM> drives a needle assembly <NUM> into the injection position, as previously discussed and depicted in <FIG>. Also, while face gear <NUM> unwinds, it drives rotation of gears <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> (see <FIG>). Rotation of gear <NUM>, in turn, provides rotational input to pump <NUM>, causing pump <NUM> to pump liquid drug from reservoir <NUM>, through septum <NUM> and the driven needle <NUM> and into the patient.

<FIG> depict one potential embodiment of pump <NUM>. Pump <NUM> includes mounting frame <NUM>, rotary drive shaft <NUM>, rotating plunger <NUM>, pump housing <NUM>, and return spring <NUM>. A first end of frame <NUM> supports a rotary drive shaft <NUM>, which is in turn connected to rotating plunger <NUM>. Rotary drive shaft <NUM> may be connected to gear <NUM>, which provides rotational input to pump <NUM> that causes rotary drive shaft <NUM> to rotate about longitudinal axis <NUM> in the direction of arrow <NUM> (e.g., in a clockwise direction), as shown in <FIG>.

<FIG> and <FIG> depict the rotating plunger <NUM> in more detail, according to some embodiments. <FIG> depict plunger <NUM> from four separate profile views, while <FIG> provides a perspective view. Plunger <NUM> comprises a substantially cylindrical elongated body having a first end <NUM> and a second end <NUM> connected by curved, cylindrical side wall <NUM>. Plunger pin <NUM> protrudes radially outward from side wall <NUM> of plunger <NUM> and may be rigidly affixed thereto. In some embodiments, pin <NUM> and side wall <NUM> may be formed of one monolithic piece; in other embodiments, pin <NUM> may be a separate part that is adhered, joined, inserted, or molded into side wall <NUM>. As depicted, pin <NUM> may be disposed adjacent to the first end <NUM> of plunger <NUM>. However, the pin may be disposed at any point along the length of plunger <NUM>. As best seen in <FIG>, plunger <NUM> may include a reduced cross-sectional area portion that may be defined by a cutout <NUM> disposed adjacent to the second end <NUM>. Cutout <NUM> is defined by a substantially planar longitudinal portion <NUM> recessed below the side wall <NUM> and connected to a lip <NUM> which steps inwards from the cylindrical side wall <NUM> of plunger <NUM>. Portion <NUM> and lip <NUM> may intersect in a transverse relationship. In one embodiment, planar portion <NUM> of cutout <NUM> faces a first radial direction, and the pin <NUM> extends in a second radial direction that is perpendicular to the first radial direction of the placement of the cutout.

Plunger <NUM> is received within pump housing <NUM>. One exemplary embodiment of housing <NUM> is depicted in greater detail in <FIG> and <FIG>; <FIG> provides a perspective view of housing <NUM>, while <FIG> provides a cross-sectional view of housing <NUM> when cut along line <NUM>-<NUM>. Housing <NUM> may be constructed from any suitable and relatively rigid material, such as an olefin plastic (e.g., cyclic olefin copolymer and/or polypropylene). The interface between housing <NUM> and plunger <NUM> may be lubricated with an appropriate pharmaceutical container lubricant, such as silicone oil.

Housing <NUM> comprises three sections: a first section <NUM>, an intermediate section <NUM>, and a third section <NUM>, each disposed along a common axis <NUM>. First section <NUM> comprises a side wall <NUM> that defines an angled pin track <NUM>. Pin track <NUM> is angled such that a plane defined by track <NUM> is not perpendicular to longitudinal axis <NUM> but is angularly offset such that a first end <NUM> of track <NUM> is further from intermediate section <NUM> than the opposite, second end <NUM> of track <NUM>. Second end <NUM> is connected to first end <NUM> of track <NUM> via an upwardly-sloping portion <NUM>, and a downwardly-sloping portion <NUM>. First section <NUM> also comprises two tabs 710a, 710b that receive and support plunger <NUM>.

Intermediate section <NUM> comprises a side wall <NUM>, and one or more axial ridges <NUM> projecting radially outward from side wall <NUM>. One or more of the ridges <NUM> have a radially inward step <NUM> oriented towards the third section <NUM> of housing <NUM>. As best shown in <FIG>, side wall <NUM> defines a cavity <NUM> internally along the axis <NUM> having an open first end <NUM> and a closed second end <NUM>. Side wall <NUM> also defines an inlet port <NUM> and an outlet port <NUM>, shown defined by radially extending arms. In one embodiment, the ports <NUM>, <NUM> are oriented in different radial directions. In one embodiment, the ports <NUM>, <NUM> are oriented extending in opposite directions (for example, angularly spaced <NUM> degrees from each other) along a transverse axis <NUM> that extends orthogonal to the longitudinal axis <NUM>. Inlet port <NUM> and outlet port <NUM> pass through side wall <NUM> and are in fluid communication with cavity <NUM>. Ducts are shown disposed on the arms in a fluid tight seal. Inlet port <NUM> is fluidically connected with an inlet duct <NUM>, while outlet port <NUM> is fluidically connected to an outlet duct <NUM>. During operation of the pump subsystem, fluid is sucked in through inlet port <NUM> / inlet duct <NUM> and into the cavity <NUM> and expelled through outlet port <NUM> / outlet duct <NUM>.

Returning to <FIG>, third section <NUM> of housing <NUM> comprises a substantially cylindrical body having a smaller cross-sectional area compared to first section <NUM> and intermediate section <NUM>. Third section <NUM> may also take the form of other shapes. Return spring <NUM> may be wrapped around third section <NUM> such that a first end of spring <NUM> abuts the inward step <NUM> of one or more of the ridges <NUM>, and a second end of spring <NUM> abuts and/or is received within a receptacle on mounting frame <NUM> (see <FIG>). Thus mounted, return spring <NUM> provides biasing pressure against housing <NUM>.

When plunger <NUM> is received within housing <NUM>, plunger <NUM> is configured to rotate about longitudinal axis <NUM> within cavity <NUM>. Plunger <NUM> is also configured to translate longitudinally along longitudinal axis <NUM> within cavity <NUM>. The biasing pressure of return spring <NUM> causes the pin track <NUM> to abut and/or engage against the underside of plunger pin <NUM> at all times while plunger <NUM> rotates within cavity <NUM>. When plunger <NUM> is received within cavity <NUM>, the surfaces that define cutout <NUM> (that is, surfaces <NUM>, <NUM>) and the interior wall of cavity <NUM> (i.e., the interior surface of side wall <NUM>) together define a working chamber <NUM> (see <FIG>) that is brought into repeated and sequential fluid-flow communication with no port, then the inlet port, then no port, and then the outlet port as the plunger moves within the cavity.

In operation, rotational input from gear <NUM> provides a rotary force to drive shaft <NUM>. The rotary force causes shaft <NUM> and plunger <NUM> to rotate about longitudinal axis <NUM> in the direction of arrow <NUM> (see <FIG>, <FIG>). As plunger <NUM> rotates within cavity <NUM>, the plunger <NUM> and housing <NUM> successively move through the series of configurations depicted in <FIG>, and <FIG>. Each of <FIG> show a profile, cross-sectional view of pump subsystem <NUM> along line <NUM>-<NUM>. Each of <FIG> show a top-down, cross-sectional view of pump subsystem <NUM> along line <NUM>-<NUM>. For clarity, the position of plunger pin <NUM> is outlined in phantom in <FIG>.

In <FIG> and <FIG>, plunger <NUM> is rotated such that plunger pin <NUM> is pointed towards the left in <FIG> and <FIG>. When plunger pin <NUM> is pointed in this direction, spring <NUM> causes pin <NUM> to engage against the lowest portion (i.e., second end <NUM>) of pin track <NUM>, thus causing plunger <NUM> to translate longitudinally to its furthest position within cavity <NUM> relative to housing <NUM>. While plunger <NUM> is at this furthest position, distal end <NUM> of plunger <NUM> may come into contact with the closed end <NUM> of cavity <NUM> (or be located close to the closed end <NUM> of cavity <NUM>), such that working chamber <NUM> has the smallest volume of any of the four configurations depicted in <FIG> and <FIG>. Also, while plunger <NUM> is at this furthest position, cutout <NUM> is oriented out of the page in <FIG>, and downwards in <FIG>. As previously mentioned, cutout <NUM> and the interior wall of cavity <NUM> (i.e., the interior surface of side wall <NUM>) define a working chamber <NUM>. When cutout <NUM> is so oriented, the curved side wall <NUM> of plunger <NUM> presses tightly against the interior surfaces of side wall <NUM> surrounding inlet port <NUM> and outlet port <NUM>, respectively, so as to establish a fluid-tight seal that blocks both ports. As a result, working chamber <NUM> is not in fluid communication with either port while in this configuration.

In <FIG> and <FIG>, plunger <NUM> is rotated such that plunger pin <NUM> is pointed into the page in <FIG>, and upwards in <FIG>. When plunger pin <NUM> is pointed in this direction, spring <NUM> causes pin <NUM> to engage against upwardly-sloping portion <NUM> of pin track <NUM>. This causes plunger <NUM> to translate longitudinally out of housing <NUM> as plunger <NUM> rotates, thus increasing the volume of working chamber <NUM>. Also, in this configuration, cutout <NUM> is oriented to the left in <FIG> and <FIG>, thus opening fluid communication between working chamber <NUM> and inlet port <NUM>. The opened fluid communication and the increasing volume of working chamber <NUM> causes fluid to be sucked into working chamber <NUM> from inlet port <NUM> as pin <NUM> rotates (or, if the fluid is stored under pressure in the drug reservoir, allows fluid to enter working chamber <NUM>).

In <FIG> and <FIG>, plunger <NUM> is rotated such that plunger pin <NUM> is pointed to the right in <FIG> and <FIG>. When plunger pin <NUM> is pointed in this direction, spring <NUM> causes pin <NUM> to engage against the highest portion (i.e., first portion <NUM>) of pin track <NUM>, thus allowing plunger <NUM> to translate longitudinally to its furthest position out of cavity <NUM> relative to housing <NUM>. When in this configuration, distal end <NUM> of plunger <NUM> is located at its shallowest position within cavity <NUM> such that working chamber <NUM> is at its largest volume of any of the four configurations depicted in <FIG> and <FIG>. Also, when in this configuration, cutout <NUM> is oriented into the page in <FIG>, or upwards in <FIG>. When cutout <NUM> is so oriented, the curved side wall <NUM> of plunger <NUM> again establishes a fluid-tight seal against both inlet port <NUM> and outlet port <NUM>, which means the working chamber <NUM> is not in fluid communication with either port.

In <FIG> and <FIG>, plunger <NUM> is rotated such that plunger pin <NUM> is pointed out of the page in <FIG>, or downwards in <FIG>. When plunger pin <NUM> is pointed in this direction, spring <NUM> causes pin <NUM> to engage against the downwardly-sloping portion <NUM> of pin track <NUM>. This causes plunger <NUM> to translate longitudinally into housing <NUM> as plunger <NUM> rotates, thus decreasing the volume of working chamber <NUM>. Also, in this configuration, cutout <NUM> is oriented towards the right in <FIG> and <FIG>, thus opening fluid communication between working chamber <NUM> and outlet port <NUM>. The opened fluid communication and the decreasing volume of working chamber <NUM> causes fluid to be expelled from working chamber <NUM> and out through outlet port <NUM> as pin <NUM> rotates. In this configuration, curved side wall <NUM> of plunger <NUM> continues to press tightly against inwardly offset segment <NUM>, thus maintaining the fluid-tight seal that blocks inlet port <NUM>.

A complete pump cycle comprises the four configurations described above in <FIG> and <FIG>. For further details regarding the operation and/or configuration of pump <NUM>, or for alternative embodiments of pump <NUM> that may be used, refer to <CIT>, the entire contents of which are hereby incorporated by reference.

Now that operation of pump <NUM> has been described, attention is directed back to <FIG>. After a predetermined time (during which the drug is being pumped into the patient), face gear <NUM> eventually rotates into a position where one of its fins <NUM> come into alignment with arm <NUM> of latch <NUM>. The sloped leading edge of fin <NUM> comes into contact with arm <NUM>, thus pushing latch <NUM> to rotate in the direction of arrow <NUM>, as depicted in <FIG>. This causes latch <NUM> to unlock secondary slide <NUM>, as described below. As gear <NUM> continues to rotate, fin <NUM> eventually clears arm <NUM> of latch <NUM>, and latch <NUM> moves back in the direction of arrow <NUM> into its neutral position under the biasing pressure of spring <NUM>.

<FIG> depict the same sequence of states of device <NUM> as <FIG> from above to better show how slides <NUM> and <NUM> move in response to unlocking of latch <NUM>. <FIG> depicts device <NUM> after pawl <NUM> has been disengaged and face gear <NUM> begins unwinding, but before latch <NUM> is unlocked. In this state, latch tab <NUM> of latch <NUM> is positioned distal to locking tab <NUM> of secondary slide <NUM>, thus preventing secondary slide <NUM> from translating distally under the biasing pressure of spring <NUM>. In <FIG>, latch <NUM> rotates in the direction of arrow <NUM>, thus clearing locking tab <NUM>. This allows secondary slide <NUM> to translate distally in the direction of arrow <NUM> (i.e., in the +x direction) due to the biasing pressure of compressed spring <NUM>. As secondary slide <NUM> translates distally, compression tab <NUM> contacts distal wall <NUM> of primary slide <NUM> and causes primary slide <NUM> to also translate distally in the direction of arrow <NUM> (i.e., in the +x direction). Eventually, latch <NUM> rotates in the direction of arrow <NUM> back to its neutral position (<FIG>) under the biasing pressure of spring <NUM>. However, since locking tab <NUM> is now distal to latch tab <NUM>, rotation of latch <NUM> back to its neutral position does not stop secondary slide <NUM> from translating distally until it hits a stop. Secondary slide <NUM> eventually translates back to its secondary slide distal position, and primary slide <NUM> eventually translates back to its primary slide distal position, as depicted in <FIG>.

<FIG> depict the same sequence of states of device <NUM> as <FIG> and <FIG> from the side to better show how distal translation of primary slide <NUM> causes the needle insertion / retraction mechanism <NUM> to retract the needle <NUM>. <FIG> depicts device <NUM> after pawl <NUM> has been disengaged and face gear <NUM> begins unwinding, but before latch <NUM> is unlocked. In this state, needle assembly <NUM> is in its injection position and head <NUM> of hammer <NUM> is in contact with ledge <NUM> of needle assembly <NUM>. In <FIG>, primary slide <NUM> begins translating distally, thus causing hammer <NUM> to rotate about pin <NUM> in the direction of arrow <NUM>. This rotation of hammer <NUM> causes head <NUM> to contact the underside of tang <NUM> of needle assembly <NUM> and pull the entire needle assembly upwards in the direction of arrow <NUM>. This upwards motion retracts needle assembly <NUM> from its injection position back to its retracted position. In particular, first leg segment <NUM> of needle <NUM> is drawn out of drug septum <NUM> and second leg segment <NUM> is drawn out of the patient's body, thus breaking the fluid path between drug septum <NUM> and the patient's body. As primary slide <NUM> continues to translate distally and hammer <NUM> continues to rotate about pin <NUM> in the direction of arrow <NUM>, head <NUM> of hammer <NUM> eventually disengages from tang <NUM> of needle assembly <NUM>, as depicted in <FIG>.

The terms "first", "second", "third", "primary", "secondary", and the like, whether used in the description or in the claims, are provided for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances (unless clearly disclosed otherwise) and that the embodiments of the disclosure described herein are capable of operation in other sequences and/or arrangements than are described or illustrated herein.

While this invention has been described as having exemplary designs, the present invention can be further modified within the scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains.

For example, in some embodiments, the drug-delivery device may not comprise a needle cartridge holding a plurality of needle assemblies; instead, the device may comprise only a single needle assembly. Such a device may be configured for single-use only, rather than for multiple uses. This single needle assembly may be configured to be inserted and/or retracted using the insertion / retraction mechanisms discussed above.

In at least some of the above-described embodiments, one or more springs in the drug-delivery device are loaded when the user actuates a loading button. When the user then actuates a dosing button, the one or more loaded springs are released to (i) operate a drive member to drive a needle assembly in operational alignment with the drive member from a retracted position to an injection position, (ii) drive a pump to pump drug fluid from a drug reservoir through the driven needle assembly, and (iii) retract the driven needle assembly from the injection position back to the retracted position. In other embodiments however, releasing the one or more loaded springs need not drive all of functions (i) through (iii) listed above. For example, in some embodiments, releasing the one or more loaded springs (upon actuation of the dosing button) may drive only function (i) but not functions (ii) and (iii). In other embodiments, releasing the one or more loaded springs upon actuation of the dosing button may drive only functions (i) and (ii) but not (iii). In yet other embodiments, releasing the one or more loaded springs upon actuation of the dosing button may drive functions (ii) and (iii), but not function (i). In general, embodiments in which releasing the one or more springs (upon actuation of the dosing button) accomplishes any one or more of functions (i) through (iii) listed above are also within the scope of this disclosure.

Claim 1:
A needle-insertion mechanism (<NUM>) for a drug-delivery device (<NUM>), the mechanism comprising:
a housing (<NUM>, <NUM>);
a drive member (<NUM>);
a needle cartridge (<NUM>) holding a plurality of needle assemblies (<NUM>), each needle assembly disposed in a separate retracted position within the needle cartridge;
one or more springs (<NUM>, <NUM>, <NUM>);
a loading button (<NUM>) coupled to the housing configured to be manually actuated to load the one or more springs using work done through actuation of the loading button, and to advance the needle cartridge so a first needle assembly of the plurality of needle assemblies is moved out of operational alignment with the drive member and a second needle assembly of the plurality of needle assemblies is moved into operational alignment with the drive member; and
a dosing button (<NUM>) coupled to the housing configured to be manually actuated after actuation of the loading button to release the one or more loaded springs to operate the drive member to drive the second needle assembly from its retracted position within the needle cartridge to an injection position.