Dual acting telescopic screw drive pump mechanism disposed externally of a reservoir in a fluid delivery device

Abstract

A fluid delivery device has a syringe barrel reservoir with a plunger, and a plunger driver assembly that includes a double-acting telescoping lead screw located behind and outside of the barrel. When the sleeve screw is rotated, the simultaneously and counter-rotating sleeve and center screws telescope out of the nested configuration of the plunger driver assembly and into the reservoir at their respective double and equal pitch and lead parameters. A nut and gear anchor fitting disposed on the end of the syringe barrel receives the sleeve screw, and the nut translates and rotates the sleeve screw in response to motor operation. The distal end of the center screw can be keyed to a plunger pusher so as to be rotationally constrained when the motor exerts rotation on the nut and sleeve screw.

Description

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 066,832, filed August 18, 2020, the contents of which are incorporated herein in their entirety. TECHNICAL FIELD

[0002] Illustrative embodiments relate generally to pump mechanisms for fluid delivery devices, such as wearable drug infusion patches. Exemplary embodiments relate generally to a screw rod for controllably extending or retracting a plunger driver in a syringe barrel reservoir that does not affect the reservoir volume to ensure biocompatibility, that can be fully retracted outside the reservoir, and keyed within the reservoir for anti-rotation control. BACKGROUND

[0003] Typical drug delivery patch pump designs are challenged by the need to achieve small size, low power consumption, accurate delivery, high reliability, and low manufacturing cost. In addition, drug delivery patch pump designs cannot affect the quality of the drug. For example, the materials used for pump mechanism components that come into contact with the delivered fluid cannot present biocompatibility issues. SUMMARY

[0004] The above and other problems are overcome, and additional advantages are realized, by illustrative embodiments.

[0005] Exemplary embodiments of the present disclosure achieve several advantages, such as minimizing the device size envelope or form factor while maintaining the beneficial features of highly reliable and proven systems such as drug pens and pen needles, syringes, or more expensive non-portable pumping systems employing a lead screw drive mechanism.

[0006] One aspect of exemplary embodiments is to provide an improved and novel double-acting, telescoping screw rod drive pump mechanism design that enables the use of a syringe barrel drug container or similar reservoir that has been proven to be drug friendly or biocompatible with drugs and other fluids delivered via a fluid delivery device.

[0007] According to an exemplary embodiment, a fluid delivery device is provided that includes a reservoir including an outlet port at a distal end, a plunger movable along a longitudinal axis of the reservoir, the plunger configured to provide a seal relative to an inner wall of the reservoir to prevent fluid disposed in a fluid chamber defined on a first side of the plunger and including the outlet port from leaking into a portion of the reservoir defined by a second side of the plunger, and a plunger driver assembly mounted at a proximal end of the reservoir and including telescoping counter-rotating screws having similar pitch and lead parameters, the screws moving from a nested configuration not extending into the reservoir to an extended configuration extending into the reservoir at a rate that is twice the respective pitch and lead parameters of the respective screws when the nut is rotated. According to aspects of illustrative embodiments, an encoder(s) can be provided relative to the plunger driver assembly to generate feedback data related to operation of the plunger driver assembly.

[0008] According to aspects of illustrative embodiments, the screws include a sleeve screw and a center screw, each having externally threaded with opposite handedness, if the externally threaded of the sleeve screw is left-handed, the externally threaded of the center screw is right-handed, and if the externally threaded of the sleeve screw is right-handed, the externally threaded of the center screw is left-handed.

[0009] According to aspects of illustrative embodiments, the internally threaded of the sleeve screw and the externally threaded of the sleeve screw have opposite handedness threads.

[0010] According to aspects of illustrative embodiments, the nut has a bore with internal threads that mate with the externally threaded on the sleeve screw to advance the sleeve screw into the reservoir when the nut is rotated.

[0011] According to aspects of illustrative embodiments, the reservoir further includes a gear anchor mounted to a proximal end thereof, the gear anchor including a bore sized to receive a distal end of the sleeve screw and to allow the sleeve screw and the center screw to extend into the reservoir when the nut is rotated. Further, the gear anchor can include a through hole for venting.

[0012] According to aspects of illustrative embodiments, the plunger driver assembly further includes a plunger pusher coupled to a distal end of the center screw.

[0013] According to aspects of illustrative embodiments, the plunger driver assembly is configured to cause the plunger to be displaced toward the proximal end of the reservoir when the plunger driver assembly is controlled to deploy the reverse-rotation screw.

[0014] According to aspects of illustrative embodiments, the central screw is connected to the plunger pusher and is rotationally constrained by an anti-rotation mechanism.

[0015] According to aspects of illustrative embodiments, the anti-rotation mechanism is the reservoir and the plunger pusher, the reservoir and the plunger pusher having a non-circular cross-section to prevent rotation of the plunger pusher within the reservoir as the sleeve screw is rotated.

[0016] According to aspects of illustrative embodiments, the plunger driver assembly further comprises an anti-rotation mechanism comprising a stop on a proximal side of the plunger pusher, the stop being sized to mate with a distal end of the central screw to prevent rotation of the plunger pusher relative to an inner wall of the reservoir as the sleeve screw is rotated. For example, the distal end of the central screw or innermost screw is sized and / or shaped to be press-fit into a correspondingly sized and / or shaped stop. Further, for example, the stop can comprise a through-hole leading to a distal side of the plunger pusher, and the distal end of the central screw extends through the through-hole. The distal end of the central screw can be heat staked at the through-hole on a distal side of the plunger pusher. The through-hole can comprise an anti-rotation groove to facilitate heat staking. Alternatively, the plunger pusher can comprise a protrusion on a distal side thereof, and the through-hole can extend through the protrusion. According to another aspect, the plunger pusher can comprise at least one through-hole for venting and / or notches along at least a portion of a perimeter thereof for venting.

[0017] According to aspects of illustrative embodiments, the reservoir comprises an inlet port connected to a fill port via an inlet fluid path, the fill port being provided in the fluid delivery device to couple with a filling apparatus, and the plunger is configured to be displaced toward a proximal end of the reservoir as fluid is introduced into the fluid chamber from the inlet port, the plunger driver assembly being configured to be in its nested configuration during filling.

[0018] According to aspects of illustrative embodiments, the reservoir is a syringe barrel type container.

[0019] According to aspects of illustrative embodiments, the reservoir and plunger have a cross-sectional shape selected from the group consisting of a non-circular shape and an elliptical cross-section.

[0020] According to an aspect of the illustrative embodiment, the respective screws have equal pitch.

[0021] Additional and / or other aspects and advantages of the illustrative embodiments will be set forth in the following description, or will be apparent from the description, or may be learned by practicing the illustrative embodiments. The illustrative embodiments may include an apparatus having one or more of the foregoing aspects and / or one or more features and combinations thereof, and a method for operating the apparatus. The illustrative embodiments may include, for example, one or more features and / or combinations of the foregoing aspects as described in the appended claims. Attached Figure Description

[0022] The above and / or other aspects and advantages of the illustrative embodiments will be more readily understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0023] Figure 1 This is a perspective view of a wearable fluid delivery device constructed according to an exemplary embodiment;

[0024] Figure 2A , 2B 2C and 2D are constructed according to exemplary embodiments. Figure 1 Partial top view, perspective view, side view and top view of the fluid conveying device, in which the cover has been removed;

[0025] Figure 3 This is a block diagram of exemplary components of a fluid delivery device constructed according to an exemplary embodiment;

[0026] Figure 4A , 4B 4C and 4D are perspective top views of a fluid delivery device with the cover removed, constructed according to an exemplary embodiment, and show different stages of filling the reservoir;

[0027] Figure 5A and 5B These are, respectively, a rear perspective view and a front perspective view of the gear anchor constructed according to the exemplary embodiment;

[0028] Figure 6A and 6B These are, respectively, a front perspective view and a rear perspective view of the plunger pusher constructed according to an exemplary embodiment;

[0029] Figure 7A and 7B These are, respectively, side views of the plunger drive assembly in the retracted position relative to the gear anchor, according to an exemplary embodiment, and Figure 7A An exploded view of the components shown;

[0030] Figure 8A , 8BFIGS. 8A, 8B, 8C, 8D, and 8E are perspective top views of a fluid delivery device with the cap removed, and illustrate different stages of discharging fluid from a reservoir by a plunger driver assembly constructed in accordance with an exemplary embodiment;

[0031] Figure 9 FIG. 8E is a perspective view of a center screw with a key lock feature constructed in accordance with an exemplary embodiment; and

[0032] Figure 10A and 10B are block diagrams of fluid delivery devices with indexing and runaway prevention features and / or encoders, respectively, in accordance with exemplary embodiments.

[0033] In all of the drawings, like reference numerals will be understood to refer to like components, features, and structures. DETAILED DESCRIPTION

[0034] As will be appreciated by those skilled in the art, there are numerous ways of carrying out examples, improvements, and arrangements of pump mechanisms for fluid delivery devices in accordance with the embodiments disclosed herein. While reference will be made to illustrative embodiments depicted in the drawings and in the following description, the embodiments disclosed herein are not meant to be exhaustive of the various alternative designs and embodiments encompassed by the disclosed technological solutions, and those skilled in the art will readily appreciate that various modifications can be made, and that various combinations can be made, without departing from the scope of the disclosed technological solutions.

[0035] The exemplary embodiments of the present disclosure achieve several advantages, such as minimizing device size envelope or form factor while maintaining the beneficial features of highly reliable and proven systems such as drug pens and pen needles, syringes, or more expensive non-portable pumping systems employing a lead screw drive mechanism. According to the exemplary embodiments described herein, a novel pump mechanism for a fluid delivery device is disclosed. A nested telescoping screw design is used for the pump mechanism, which enables the use of a syringe barrel type drug container or similar reservoir that has been proven to be drug friendly or biocompatible with the drugs and other fluids delivered via the fluid delivery device. A double-acting, telescoping lead screw mechanism is located behind and external to the syringe barrel reservoir. The exemplary embodiments described herein achieve a highly precise, controllable, compact, and efficient pump design with minimal to no impact on drug quality. According to the exemplary embodiments, a telescoping, simultaneously counter-rotating sleeve screw and center screw are employed, which telescope out of their nested configuration at twice their respective and equal pitch / lead parameters. To achieve the counter-rotating function, the outer threads of the innermost screw and sleeve screw (as well as the threads of the container cap) must have opposite hand. The innermost or center screw can be left-handed or right-handed, as long as the outer threads of the sleeve screw (and the inner threads of the container cap) are correspondingly right-handed or left-handed. Furthermore, the inner threads on the sleeve screw always have opposite hand compared to the outer threads of the sleeve screw. A power source turns a gear train, which turns the sleeve screw through a nut. As the threads on the sleeve screw rotate around the center screw, the center screw, which is keyed to the plunger pusher and cannot rotate, advances. The telescoping action reduces the overall footprint of the plunger drive mechanism compared to a single advancing lead screw used by, for example, existing patch pumps. It should be noted that the total screw drive torque is equal to the combined torque of the innermost screw and sleeve screw rotation (added, as is the total effective lead). Also, whether the innermost screw is left-handed or right-handed is somewhat arbitrary, unless the force from the drive mechanism, motor, and / or indexer has a preferred rotational direction.

[0036] Figure 1 is a perspective view of a wearable fluid delivery device 10 constructed in accordance with exemplary embodiments. The fluid (e.g., drug) delivery device 10 includes a base 12, a cover 14, and an insertion mechanism 16 in an unexpanded position. The fluid delivery device 10 can be filled with fluid (e.g., drug) by a user inserting a needle of a filled syringe 36 into a fill port (not shown) disposed in the base 12 having an inlet fluid path from the fill port to the reservoir. It should be appreciated that the fluid delivery device 10 can use different mechanisms and methods to fill with fluid (e.g., drug).

[0037] Figure 2A 、 2BFIGS. 2C and 2D are, respectively, a partial top view, perspective view, side view, and top view of a fluid delivery device constructed in accordance with an exemplary embodiment Figure 1 FIG. 1 is a partial top view of a fluid delivery device constructed in accordance with an exemplary embodiment. The device 10 includes a base plate 12 supporting an insertion mechanism 16, a motor 18, a power source (e.g., a battery 20), a control board 50, and a reservoir 22 or container for storing a fluid to be delivered to a user through an outlet fluid path 24 from an outlet port of the reservoir to the insertion mechanism 16. The reservoir 22 can also have an inlet port connected through an inlet fluid path 26 to a fill port (e.g., provided in the base plate 12). The reservoir 22 contains a plunger 28 having a stopper assembly. The proximal end of the reservoir 22 is also provided with a plunger driver assembly 30 having a telescoping, counter-rotating sleeve screw 72 and center screw 74, a gear anchor 34, a nut 70 that rotates via a gear train 32 connected to the motor 18 and a gear box 44.

[0038] Figure 3 FIG. 2A is a block diagram of exemplary components of a fluid delivery device constructed in accordance with an exemplary embodiment. The cover / housing or housing of the device 10 is indicated at 14, and the device 10 has a skin retention subsystem 40, e.g., an adhesive pad that connects the device 10 to the skin of a user. The fluid delivery device 10 also includes a reservoir 22, an insertion mechanism 16, and a fluid displacement module 42, which can include a motor 18, a motor housing and gear box 44, a gear train 32, a pump mechanism (e.g., a plunger driver assembly 30), and an outlet path 24. The fluid delivery device also includes electrical components such as a power source module (e.g., a battery 20), and an electrical module 50, which includes a controller 52, a motor driver 54, an optional sensing module 56 for sensing fluid flow conditions (e.g., occlusion or runaway of the pump mechanism), an optional audio driver 58 (e.g., for indicating an ongoing dose, reservoir low, occlusion, successful pairing with an external device, or other conditions via an audible alert such as a buzzer), and an optional visual driver 60 for providing visual feedback via light emitting diodes and / or an optional haptic driver for providing haptic feedback via a vibrating component, and an optional wireless driver 62 for wireless communication between the fluid delivery device and an optional remote pump control device (e.g., a smartphone or a dedicated controller 63). With respect to the sensing module 56, the fluid delivery device can be provided, for example, with one or more encoders to provide feedback of the drive mechanism (e.g., the plunger driver assembly 30) for indexing and runaway prevention purposes of the pump mechanism.

[0039] Figure 4A , 4B4C and 4D are perspective top views of a fluid delivery device with the cover removed, constructed according to an exemplary embodiment, and illustrate different stages of filling the reservoir. The fluid filling chamber 64 in the reservoir 22 is defined by the distal or front side of a plunger 28, which is configured to seal the fluid from entering the reservoir portion defined by the proximal or rear side of the plunger, such that the plunger drive assembly 30 or the gear anchor 34 does not contact the fluid being delivered from the reservoir.

[0040] exist Figure 4A In the middle, the reservoir 22 contains no fluid, and the plunger 28 is at its furthest position. Figure 4A to 4D The plunger driver assembly 30 is shown fully retracted. A user can insert the needle of a filled syringe 36 into a filling port (not shown) provided on a substrate 12, which has an inlet fluid path 26 from the filling port to the reservoir 22, as shown... Figure 2D As shown, when fluid is transferred from syringe 36 to reservoir 22 via inlet fluid path 26, the volume of the fluid chamber in reservoir 22, defined by the front surface of plunger 28, increases, as shown below. Figure 4B , 4C As shown in Figure 4D, the plunger 28 has a stopper assembly to prevent leakage of any fluid held in the fluid chamber portion 64 of the reservoir 22. The stopper assembly may include, for example, an elastic material similar to that of a syringe stopper.

[0041] Figure 5A and 5B These are rear and front perspective views of a gear anchor 34 constructed according to an exemplary embodiment. The gear anchor 34 has one or more protrusions 80 for press-fitting or otherwise engaging a pin or other component (not shown) disposed on a container mount (e.g., a wall on a substrate, mounting plate, superstructure, or other structure in the device housing 14). While the protrusions (e.g., tabs) 80 hold the gear anchor 34 in place to respond to forces from plunger movement and fluid pressure, other alternative exemplary embodiments can be used to support the gear anchor 34 over a relatively large area to avoid localized deformation. The gear anchor 34 has a hole 82 to receive a first portion of a nut 70. The hole 82 has threads 84 configured to engage with the external thread 72a of a sleeve screw 72. The number of threads 84 can be adjusted to balance torque and motion stability. The number of threads 84 can be increased without negatively affecting the length (i.e., only requiring a small change to the geometry of the drive nut). A recessed rear surface 86 is configured to rotatably receive the distal end of the nut 70. The gear anchor 34 has a front surface 88, which is positioned when the plunger drive assembly 30 is fully retracted and the reservoir is filled (e.g., as shown in the image). Figure 4DThe front surface of the pusher 76 can abut the plunger 28, but depending on the size of the reservoir 22 and the plunger driver assembly 30, the gear anchor 34 does not necessarily have to abut the plunger. The gear anchor 34 also has at least one hole or through hole 85 for venting. As described below, the pusher 76 also has an opening(s) and / or gap(s) to allow venting as it moves axially in the reservoir 22.

[0042] Figure 6A and 6B are front and rear perspective views, respectively, of a plunger pusher 76 configured in accordance with an exemplary embodiment. The plunger pusher 76 has a stop 90 on its rear surface to accommodate a key feature 74b on the center screw 74. An optional protrusion 92 on the front surface of the pusher 76 can strike the rear surface of the plunger 28. The pusher 76, along with the cap 34 on the reservoir 22, is provided with feature(s) that allow venting, either together or selectively. For example, venting features can be provided along at least a portion of the perimeter of the pusher 76, and the venting features can be in the form of scalloped edges that include notches 76a. When the notches 76a are provided on the perimeter of the pusher 76, the features can be arranged to minimize axial translation friction through a biasing design, and the tolerances of the edges around some of the features 76a are set to be larger than the tolerances of the remaining notch edges so as to contact the inner reservoir barrel surface first, thereby preventing rotation. The pusher 76 can also be provided with one or more through holes 76b in the plate-like portion of the pusher for venting.

[0043] Figure 7A and 7B are side views of the plunger driver assembly 30 in a retracted position relative to the gear anchor 34, and Figure 7A are exploded views of the components shown in FIGS. 17A and 17B. The plunger driver assembly 30 includes a nut 70 that has teeth 70b on the portion of the nut that engages the gear train 32 and the motor 18. The distal end portion of the nut 70 is rotatably housed in the gear anchor 34, and an internal thread 70c in the nut 70 engages an external thread 72a of a sleeve screw 72. An internal thread in the cavity 72b of the sleeve screw engages an external thread 74a of the innermost screw or center screw 74. As shown in FIG. 18A, the distal end of the center screw 74 is provided with a key feature 74b that engages a stop 90 on the plunger pusher 76. As shown in FIG. 18B, the protrusion 92 can be provided with an anti-rotation groove 92a. When assembled, the post on the distal end of the innermost screw 74 can extend into the stop 90, through the pusher 76, and slightly beyond the protrusion 92 thereof. The post on the distal end of the innermost screw 74 cooperates with the groove 92a during heat staking of the innermost screw 74 relative to the pusher 76. The heat staked end of the protrusion 92, for example, is flush with the stop 90. Figure 9 Figure 6A Figure 7A ​​As shown in the figure. Nut 70 may be equipped with encoder 70a for calibration and accurate dosage delivery, and provide feedback to electrical module 50 to further protect drive nut 70 from runaway or undesirable or inaccurate pump motor action and rotation.

[0044] Figure 8A , 8B Images 8C, 8D, and 8E are perspective top views of a fluid delivery device with the cap removed, illustrating different stages of fluid discharge from a reservoir via a plunger drive assembly 30 constructed according to an exemplary embodiment. Figure 8A In the retracted position, the plunger actuator assembly 30 is fully extended, and the volume of the fluid-filled chamber portion 64 of the reservoir 22 is maximized. The double-acting, telescopic guide screw design of the plunger actuator assembly 30, mounted behind the reservoir 22, facilitates maximizing the available reservoir fluid volume while minimizing the total footprint of the reservoir on the substrate 12. When the plunger actuator assembly 30 is fully extended, the rear portion of the sleeve screw 72 extends beyond the nut 70, but the total length of the plunger actuator assembly 30 in its non-extended state, and thus the total footprint of the reservoir 22 and the plunger actuator assembly 30, is minimized due to the double-acting, telescopic guide screw design according to the exemplary embodiment.

[0045] exist Figure 8B In this configuration, nut 70 is rotated by the engagement of its teeth 70b with the motor and gearbox 18, as well as the intermediate power transmission gear train 32. The internal thread 70b of the nut and the hole thread 84 of the gear anchor 34 engage with the external thread 72a of the sleeve screw 72, causing the sleeve screw 72 to advance through the nut 70 and gear anchor 34 and into the reservoir 22. Simultaneously, the rotation of the sleeve screw 72 causes the non-rotational advancement of the central screw 74 keyed to the plunger pusher 76. As a result, as the plunger pusher 76 is pushed distally to abut against the plunger 28, the plunger 28 is pushed distally. Figure 8C , 8D Figure 8E shows a further bidirectional extension of the sleeve screw 72 and the center screw 74 by substantially equal lengths as the nut is rotated by the motor and gearbox 18 and the intermediate power transmission gear train 32.

[0046] refer to Figure 6B and Figure 9The key feature 74b on the center screw 74 and its corresponding detent 90 on the rear surface of the plunger pusher 76 provide an anti-rotation mechanism for the plunger pusher 76 relative to the reservoir 22 as the nut of the plunger driver assembly 30 is rotated by the motor and gear box 18 and intermediate power transmission gear train 32. The center screw 74 engages the plunger pusher 76 using a key feature. This key feature can engage with a non-circular plunger pusher geometry, thereby preventing rotation by geometry, or can engage with an intermediate structure for preventing rotation in a working syringe barrel type reservoir 22. This key feature 74b should be smaller than the outer threading of the same innermost screw, e.g., center screw 74, so that it can be assembled from the rear end of the assembly. For example, the distal end of the center screw 74 can be sized and / or shaped to engage a corresponding sized and / or shaped detent or notch 90 in the plunger pusher 76, which prevents any limited rotation imparted on the center screw 74 by the other components 70 and 72 from causing rotation of the plunger pusher 76 relative to the inner wall of the reservoir 22. This design can also rely on an oval syringe barrel type reservoir to contain the medication and provide the anti-rotation function. The oval also has the added benefit of potentially saving the height of the device.

[0047] The exemplary embodiments described herein employ an oval syringe barrel type reservoir 22 to contain the medication or fluid to be delivered. The oval syringe barrel type reservoir 22 provides an anti-rotation function and related benefits. For example, the anti-rotation provided by the inherent design of the oval syringe barrel type reservoir 22 naturally prevents rotation of the barrel when a torque is applied. The oval also has the added benefit of potentially saving the height of the entire device. However, separate components can be employed to achieve the same anti-rotation. For example, the center screw 74 can be keyed to a detent or other feature 90 in the plunger pusher 76, thus achieving an anti-rotation of the plunger driver assembly 30 relative to the inner wall of the reservoir 22 during axial translation even if the reservoir 22 is not oval (e.g., has a circular cross-section).

[0048] The reservoir 22 can be constructed to be durable, i.e., not removable, but rather pre-installed within the fluid delivery device housing 14. The material of the reservoir 22 can be similar to a syringe barrel and associated stopper. The reservoir 22 can be pre-filled and the plunger driver assembly 30 initially in the retracted position. Alternatively, the fluid delivery device housing 14 can be provided with a fill port and a fluid passageway 26 from the fill port to the reservoir 22. The fill port can be constructed to be filled by a user with a syringe or by use of a fill station fluidly connected to the fill port.

[0049] The exemplary embodiments described herein employ a number of technical principles, such as: (a) wedge forces of screws (e.g., opposite threads of sleeve screw 72 and center screw 74); (b) sliding coupling between driver, internally threaded nut 70, and sleeve screw 72 (e.g., internally threaded nut 70 and sleeve screw 72 rotate together, but screw 72 translates axially outside of nut 70); (c) anti-rotation features for center screw 74 inside of cartridge reservoir (e.g., on plunger pusher 76 or separate structure); (d) friction and gear power transmission relative to nut 70 and various threaded components; (e) injection cartridge reservoir or reservoir 22 and aspect ratio adjustment for adjusting dosing resolution according to drug type and use scenario; and (f) optional flat battery type battery 20 for space savings.

[0050] It should be appreciated that the exemplary embodiments described herein can be subject to operational variations and alternative configurations. For example, different lead screw designs can be employed to vary dosing resolution. Encoder(s) can be employed to provide feedback for drive mechanism 30. Indexing drive can be employed to repeatedly and fail-safe advance plunger 28. In general, non-circular syringe barrel cross-sections can be employed to optimize space utilization and adjust device size for optimal fit to user comfort. Syringe cartridge reservoir 22 can vary in aspect ratio, i.e., a smaller aspect ratio (wider cross-section, shorter barrel) can be employed to deliver drug at low resolution, while a large aspect ratio can be employed to facilitate more precise dosing, according to drug type and delivery rate, resolution needs. Further, the design is based on a basic screw drive mechanism, where the lifting torque is a function of the axial load (force or pressure) applied, the pitch, the friction parameters, and the diameter. In some cases, the equation can be further expanded to obtain full details of the thread geometry, such as the flank and lead angles, as well as many other special parameters. ACME threads can generally be employed to balance lifting torque, power required, efficiency, and other functional parameters (such as operation smoothness) and cost.

[0051] Figure 10A and 10BFIGS. 1-3 are block diagrams of fluid delivery devices 10 according to exemplary embodiments having indexing and runaway prevention features and / or encoders 98 generally indicated at 96. The indexing and runaway prevention devices 96 can be provided relative to the drive nut 70 to ensure controlled rotation of the nut 70 by the motor, thereby preventing runaway of the pump mechanism. As described above, rotation of the drive nut 70 results in axial translation of the sleeve screw 72, which, due to the telescoping, simultaneously counter-rotating arrangement of screw threads described herein, also results in axial translation of the central screw 74. The central screw 74 transmits the axial motion to the pusher 76 of the plunger 28. The cap or gear anchor 34 of the reservoir provides linear and anchor support to the syringe barrel type container or housing from the friction of the sleeve screw. The gear anchor 34 can also provide venting to the syringe barrel type container or housing as well as anchor support, as well as linear and rotational support from axial motion and torque of the pusher due to engagement of the innermost screw 74. An encoder (e.g., a backup encoder) 98 can also be connected to the drive nut 70 and provide feedback to the electrical module 50 to further protect the drive nut 70 from runaway or undesired or inaccurate pump motor action and rotation (e.g., the electrical module can power down the motor if the encoder 98 senses a runaway condition).

[0052] The exemplary embodiments described herein, and their equivalents, provide technical solutions to a number of technical problems with existing fluid delivery devices, particularly patch or wearable fluid delivery devices. For example, none of the existing wearable, disposable patch pumps have the nested, telescoping, simultaneously counter-rotating screw technology described herein. The use of the exemplary embodiments enables the use of a standard syringe barrel type container as the reservoir 22, thereby simplifying drug compatibility, while bringing significant space savings for the mechanical drive mechanism that is entirely located outside of the syringe barrel and behind the moving plunger 28. Large volume reservoirs can be used that exceed the functionality of existing devices on the market.

[0053] Furthermore, the compact design provided by the exemplary embodiments allows for additional flexibility in reservoir cross-sectional design, thus enabling the fluid delivery device designer to have additional design control that can benefit dosing accuracy, for example, by slightly reducing the cross-section (and extension length), thereby requiring more travel to dispense a minimum fluid dose. This increased travel corresponds to greater rotation of the rotary drive gear, which in turn means that the drive motion can be more precise.

[0054] Another technical solution provided by the example embodiments is the use of an elliptical cross-section syringe barrel container for the reservoir 22. For example, via the configuration of the nut 70 and the gear anchor 34, a rotating screw (e.g., screw 72) pushed on the barrel will naturally impart rotational motion to the barrel 22. Thus, the physical feature is beneficial to prevent rotation. The elliptical syringe cross-section accomplishes this requirement as it does not allow rotation like a circular cross-section. It should be appreciated that the cross-sectional shape of the reservoir and plunger can be any non-circular shape. While the ellipse is a geometrically easier cross-sectional shape to implement for ease of sealing and balancing forces, other shapes can achieve better packaging. Depending on how the filling process is implemented, additional methods of preventing rotation can be implemented. For example, if variable priming with the syringe 36 is desired (e.g., by the patient), the plunger 28 can be assembled to the lowest point and pushed to the initial position by the priming volume. In the case where the anti-rotation feature is attached to the innermost screw (e.g., center screw 74), the same screw set can be advanced and then properly engage the plunger by having pre-aligned engagement features.

[0055] The configuration of the components of the plunger driver assembly 30 relative to the reservoir 22 and plunger 28 accomplishes a number of other advantages. For example, having the plunger driver assembly 30 mounted at the proximal end of the reservoir 22 and having a nested structure that does not extend into the reservoir until the nut 70 is rotated optimizes the use of the reservoir chamber for fluid delivery without having to accommodate the plunger driver components prior to delivery. Additionally, the overall length of the reservoir can be substantially the same as the length of the housing, adding a small amount of headspace to accommodate the gear train 34 connected to the drive gear teeth 70b of the nut 70 and the nominal length of the sleeve screw 72 extending from the nut in the fully retracted position. Thus, the overall footprint of the pump mechanism and the longitudinal axis dimension of the fluid delivery device housing 14 is minimized. The use of the design of the plunger 28 and plunger driver assembly 30 also minimizes the contact of the pump mechanism with the fluid being delivered to ensure biocompatibility between the fluid and the fluid delivery housing. The example embodiments described herein employ nested telescoping screws of appropriate size and thread configuration to achieve controlled movement of the syringe barrel reservoir plunger 28. Thread technology is well understood and is capable of repeated and forceful movement. When driven by the motor 18 with appropriate resolution of control, the nested screws (e.g., 72 and 74) can provide precise movement under almost all environmental conditions. Furthermore, the drive mechanism (e.g., plunger driver assembly 30) does not affect the substantial volume of the fluid chamber 64 in which the drug resides, thus having no impact on any compatibility issues.

[0056] While various personnel including, but not limited to, patients or healthcare professionals can operate or use the illustrative embodiments of the present disclosure, for the sake of brevity, the operator or user will be referred to hereinafter as the "user."

[0057] While various fluids can be employed in the illustrative embodiments of the present disclosure, for the sake of brevity, the liquid in the injection device will be referred to hereinafter as a "fluid".

[0058] Those skilled in the art will appreciate that the disclosure is not limited in its application to the details of construction and the arrangements of components set forth in the above description or illustrated in the drawings. The embodiments herein are capable of other embodiments and of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of "including," "comprising" or "having" and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless limited otherwise, the terms "connected," "coupled," and "mounted," and variations thereof herein are used broadly and encompass direct and indirect connections, couplings, and mountings. In addition, the terms "connected" and "coupled" and variations thereof are not restricted to physical or mechanical connections or couplings. Furthermore, terms such as up, down, bottom, and top are relative and are used for ease of description and are not limiting.

[0059] Components of the example devices, systems, and methods employed in accordance with the illustrated embodiments can be implemented, at least partially, in digital electronic circuitry, analog electronic circuitry, or in computer hardware, firmware, software, or in combinations thereof. These components can be implemented, for example, as a computer program product such as a computer program, program code, or computer instructions tangibly embodied in an information carrier or machine readable storage device, for execution by, or to control the operation of, data processing apparatus such as a programmable processor, a computer, or multiple computers.

[0060] The above description and drawings are merely illustrative, and are not to be taken as limiting the example embodiments in any way except as set forth in the appended claims. In particular, it is recognized that those skilled in the art can readily conceive other techniques for combining the various components of the various illustrative embodiments already described above in a variety of other ways, all of which are considered to be within the scope of the claims.

Claims

1. A fluid delivery device comprising: a reservoir including an exit port at a distal end, and a plunger movable along a longitudinal axis of the reservoir, the plunger configured to provide a seal against an inner wall of the reservoir to prevent leakage of fluid disposed in a fluid chamber defined on a first side of the plunger and including the exit port into a portion of the reservoir defined by a second side of the plunger; and a plunger driver assembly mounted at a proximal end of the reservoir and including telescoping counter-rotating screws having similar pitch and lead parameters, the screws moving from a nested configuration not extending into the reservoir to an extended configuration extending into the reservoir at a rate of twice the respective pitch and lead parameters of the respective screws upon rotation of a nut; wherein the screws include a sleeve screw and a center screw each having externally threaded opposite handedness, if the externally threaded sleeve screw is left handed, the externally threaded center screw is right handed, and if the externally threaded sleeve screw is right handed, the externally threaded center screw is left handed; wherein the reservoir further includes a gear anchor mounted to a proximal end thereof, the gear anchor including a bore sized to receive a distal end of the sleeve screw and allow the sleeve screw and the center screw to extend into the reservoir upon rotation of the nut.

2. The fluid delivery device of claim 1, wherein the internally threaded sleeve screw and the externally threaded sleeve screw have oppositely handed threads.

3. The fluid delivery device of claim 1, wherein the gear anchor includes a through bore for venting.

4. The fluid delivery device of claim 1, wherein the plunger driver assembly further includes a plunger pusher coupled to a distal end of the center screw.

5. The fluid delivery device of claim 4, wherein the plunger pusher is configured to separately abut the plunger and axially push the plunger toward a distal end of the reservoir when the plunger driver assembly is controlled to deploy the counter-rotating screws to expel a specified amount of fluid from the fluid chamber in the reservoir by displacement of the plunger.

6. The fluid delivery device of claim 1, wherein the center screw is connected to the plunger pusher and is rotationally constrained by an anti-rotation mechanism.

7. The fluid delivery device of claim 6, wherein the anti-rotation mechanism is the reservoir and the plunger pusher having a non-circular cross-section to prevent rotation of the plunger pusher within the reservoir upon rotation of the sleeve screw.

8. The fluid delivery device of claim 1, wherein the plunger driver assembly further comprises an anti-rotation mechanism comprising a stop on a proximal side of the plunger pusher sized to mate with a distal end of the central screw to prevent rotation of the plunger pusher relative to an inner wall of the reservoir as the sleeve screw is rotated.

9. The fluid delivery device of claim 8, wherein the distal end of the central screw is sized and / or shaped to press fit into the correspondingly sized and / or shaped stop.

10. The fluid delivery device of claim 8, wherein the stop comprises a through hole to a distal side of the plunger pusher and the distal end of the central screw extends through the through hole.

11. The fluid delivery device of claim 10, wherein the distal end of the central screw is heat staked at the through hole distal to the plunger pusher.

12. The fluid delivery device of claim 11, wherein the through hole comprises an anti-rotation groove.

13. The fluid delivery device of claim 10, wherein the plunger pusher comprises a protrusion on a distal side thereof and the through hole extends through the protrusion.

14. The fluid delivery device of claim 4, wherein the plunger pusher comprises at least one through hole for venting.

15. The fluid delivery device of claim 4, wherein the plunger pusher comprises a notch along at least a portion of a perimeter thereof for venting.

16. The fluid delivery device of claim 1, wherein the reservoir comprises an inlet port connected to a fill port via an inlet fluid path, the fill port provided in the fluid delivery device to couple with a fill apparatus, and the plunger is configured to be displaced toward a proximal end of the reservoir as fluid is introduced into the fluid chamber from the inlet port, the plunger driver assembly configured to be in its nested configuration during filling.

17. The fluid delivery device of claim 1, wherein the reservoir is a syringe barrel type container.

18. The fluid delivery device of claim 1, wherein the reservoir and the plunger have a cross-sectional shape selected from the group consisting of a non-circular shape and an elliptical cross-section.

19. The fluid delivery device of claim 1, wherein the respective screws have equal pitches.

20. The fluid delivery device of claim 1, wherein the fluid delivery device further comprises an encoder disposed relative to the plunger driver assembly to generate feedback data related to operation of the plunger driver assembly.

Images