Multiple telescopic screw driven pumps with anti-internal screw rotation in fluid delivery devices

Abstract

A fluid delivery device having a syringe barrel type reservoir with a plunger and a plunger driver assembly comprising nested telescoping screws including an innermost screw keyed to a first side of the plunger or intermediate pusher to prevent rotation. In a fully retracted position, the nested screws do not extend into the reservoir. The nested screws all have right hand threads and employ the same pitch in their respective internal and external thread designs. The outermost screw is connected to a motor for controllably rotating. The decreasing torque ratio and anti-rotation features from the outermost screw member to the innermost screw member allow the innermost screw to advance the plunger into the reservoir before the adjacent concentric screw member begins to rotate and advance within its corresponding screw, and so on, thereby translating the plunger and expelling fluid in a fluid chamber defined on the other side, or second side, of the plunger.

Description

[0001] This application claims the benefit of U.S. Provisional Application Serial No. 63 / 066,851, filed August 18, 2020, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0002] Some illustrative embodiments generally relate to pump mechanisms used in fluid delivery devices such as wearable drug infusion patches. Some illustrative embodiments generally relate to nested telescopic screws for controllably extending or retracting plunger actuators within a syringe barrel-type reservoir, the plunger actuators not affecting the reservoir volume to ensure biocompatibility, being fully retractable outside the reservoir, and keyed to the plunger for anti-rotation control. Background Technology

[0003] Typical drug delivery patch pump designs face the challenge of achieving small size, low power consumption, accurate delivery, high reliability, and low manufacturing cost. Furthermore, the design of drug delivery patch pumps must not compromise drug quality. For example, the materials used in pump mechanism components that come into contact with the delivered fluid must not have biocompatibility issues. Summary of the Invention

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

[0005] The exemplary embodiments of this disclosure achieve several advantages, such as minimizing the device size envelope or shape factor, while maintaining the highly reliable and proven beneficial characteristics of more expensive non-portable pumping systems such as pens and pen needles, syringes, or those employing guide screw drive mechanisms.

[0006] One aspect of the illustrative embodiments is to provide an improved and novel nested telescopic screw design that enables the use of syringe-type drug containers or similar reservoirs, which have been shown to be drug-friendly or biocompatible with drugs and other fluids delivered via fluid delivery devices.

[0007] According to some illustrative embodiments, a fluid delivery device is provided, comprising a reservoir and a plunger. The reservoir includes an outlet port at a distal end, and the plunger is movable along a longitudinal axis of the reservoir. The plunger is configured to provide a seal relative to the inner wall of the reservoir to prevent fluid supplied 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. The fluid delivery device has a plunger drive assembly mounted at a proximal end of the reservoir, the plunger drive assembly including a plurality of nested telescopic screws, wherein, when the outermost drive screw is rotated, the screws extend from a nested configuration where the screws do not extend into the reservoir to an extended configuration where the screws extend from the proximal end of the reservoir into the reservoir. The plurality of nested telescopic screws includes an innermost screw connected to the plunger and restricted from rotation by an anti-rotation mechanism.

[0008] According to some aspects of some illustrative embodiments, the reservoir is a syringe-type container.

[0009] According to some aspects of some illustrative embodiments, the anti-rotation mechanism is a plunger and a reservoir having a non-circular cross-section to prevent the plunger from rotating within the reservoir when the outermost drive screw is rotated. For example, both the reservoir and the plunger have an elliptical cross-section.

[0010] According to some aspects of some illustrative embodiments, the anti-rotation mechanism includes a pusher disposed between the plunger and the distal end of the innermost screw. The pusher abuts against the proximal side of the plunger and is configured to move along the longitudinal axis of the reservoir in response to rotation of the outermost screw.

[0011] According to some aspects of some illustrative embodiments, the pusher includes a keyed feature that cooperates with a corresponding keyed feature on the distal end of the innermost screw to engage the innermost screw with the pusher. For example, the keyed feature of the pusher includes a stop, and the corresponding keyed feature on the distal end of the innermost screw is sized and / or shaped to be press-fitted into the stop of the corresponding size and / or shape. Furthermore, for example, the stop may include a through-hole leading to the distal side of the pusher, and the distal end of the innermost screw may extend through the through-hole. The distal end of the innermost screw may be heat-fused at the through-hole on the distal side of the pusher. The through-hole may include an anti-rotation slot to facilitate heat fusion. Alternatively, the pusher may include a protrusion on its distal side, and the through-hole may extend through the protrusion. According to another aspect, the pusher may include at least one through-hole for ventilation, and / or a notch for ventilation along at least a portion of its periphery.

[0012] According to some aspects of some illustrative embodiments, the anti-rotation mechanism includes a stop on a second side of the plunger, sized to cooperate with the distal end of the innermost screw to prevent the plunger from rotating relative to the inner wall of the reservoir when the outermost drive screw is rotated. For example, the distal end of the innermost screw is sized and / or shaped to be press-fitted into a stop of a corresponding size and / or shape.

[0013] According to some aspects of some illustrative embodiments, the inner diameter and internal thread dimensions of the outermost drive screw of a plurality of nested telescopic screws are configured to receive a sleeve screw, the external thread of the sleeve screw being configured to cooperate with the internal thread to move the sleeve screw within the outermost drive screw forward when the outermost drive screw is rotated.

[0014] According to some aspects of some illustrative embodiments, the inner diameter and internal thread size of the sleeve screw are configured to receive the innermost screw. The innermost screw has an external thread configured to cooperate with the internal thread of the sleeve screw to allow the innermost screw to advance within the sleeve screw as the sleeve screw rotates.

[0015] According to some aspects of some illustrative embodiments, the torque ratio of the innermost screw is less than that of the sleeve screw, and the torque ratio of the sleeve screw is less than that of the outermost drive screw, so that the innermost screw is allowed to extend into the reservoir along the sleeve screw before the sleeve screw begins to rotate relative to the outermost drive screw and move forward into the reservoir, while the innermost screw is restricted from rotating.

[0016] According to some aspects of some illustrative embodiments, a plurality of nested telescopic screws have right-hand threads and corresponding internal and external screw parameters with the same pitch. Alternatively, a plurality of nested telescopic screws have left-hand threads and corresponding internal and external screw parameters with the same pitch.

[0017] According to some aspects of some illustrative embodiments, the reservoir also includes a gear anchor mounted to its proximal end. The gear anchor includes an orifice sized to receive the distal end of the outermost drive screw and allows nested telescopic screws to extend into the reservoir when the outermost drive screw is rotated. For example, the gear anchor is disc-shaped and sized to press-fit into the proximal end of the reservoir. For example, the orifice in the gear anchor can be configured to provide stable support to the outermost drive screw while allowing the outermost drive screw to rotate relative to the gear anchor. Furthermore, the gear anchor may have a through-hole for venting.

[0018] According to some aspects of some illustrative embodiments, when the plunger drive assembly is in its nested configuration, the distal end of the innermost screw is flush with the distal end of the gear anchor.

[0019] According to some aspects of some illustrative embodiments, when the plunger drive assembly is in its nested configuration, the distal end of the innermost screw protrudes from the distal side of the gear anchor by a specified length, which corresponds to the depth of a stop provided on the second side of the plunger or on an intermediate pusher between the plunger and the distal end of the innermost screw.

[0020] According to some aspects of some illustrative embodiments, the fluid delivery device includes a thrust bearing feature disposed relative to a plunger driver assembly and a support structure for the plunger driver assembly to minimize axial thrust loads from the telescopic screw. For example, the thrust bearing feature may include a cap disposed on the outermost drive screw, the cap having a boss for contacting a portion of the support structure to resist axial thrust loads directed towards the proximal end of the plunger driver assembly and generated by fluid in the plunger driver assembly, the plunger, or the fluid chamber.

[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. 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. Illustrative embodiments may include, for example, one or more features and / or combinations of the foregoing aspects as recited 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 example embodiment;

[0024] Figure 2 yes Figure 1 A perspective view of a fluid delivery device, in which the covering has been removed;

[0025] Figure 3 This is a block diagram of an example component of a fluid transport device constructed according to an example embodiment;

[0026] Figure 4A and Figure 4B These are a top view and a perspective top view of the fluid delivery device, respectively. For clarity, the cover of the fluid delivery device has been removed to depict the plunger drive assembly constructed according to the example embodiment.

[0027] Figure 5A plunger drive assembly constructed according to an example embodiment and including a three-layer telescopic guide screw design is described;

[0028] Figure 6A and Figure 6B A rear perspective view and a front perspective view of the gear anchor according to the example embodiment are depicted respectively;

[0029] Figure 7A , Figure 7B and Figure 7C A plunger plug and a pusher assembly according to an example embodiment are depicted, the plunger plug and pusher assembly being configured to be keyed to the innermost nested screw;

[0030] Figure 8A and Figure 8B These are a top view and a perspective top view of the fluid delivery device. For clarity, the cover of the fluid delivery device has been removed to depict a plunger driver assembly with a four-layer telescopic guide screw design constructed according to another example embodiment.

[0031] Figure 9A , Figure 9B and Figure 9C The diagram shows... Figure 8A and Figure 8B The corresponding position of the plunger drive assembly;

[0032] Figure 10 A plunger drive assembly constructed according to an example embodiment and including a four-layer telescopic guide screw design is depicted;

[0033] Figure 11 This is a partial side view of a fluid transport device with an axial thrust bearing feature constructed according to an example embodiment.

[0034] In all the accompanying drawings, the same reference numerals will be understood to refer to the same elements, features, and structures. Detailed Implementation

[0035] As those skilled in the art will understand, there are various ways to implement examples, modifications, and arrangements of the pumps according to the embodiments disclosed herein. Although reference will be made to the illustrative embodiments depicted in the accompanying drawings and the following description, the embodiments disclosed herein are not intended to be exhaustive of all alternative designs and embodiments encompassed by the disclosed technical solutions, and those skilled in the art will readily understand that various modifications and combinations can be made without departing from the scope of the disclosed technical solutions.

[0036] The exemplary embodiments of this disclosure achieve several advantages, such as minimizing the device size envelope or shape factor, while maintaining the highly reliable and proven beneficial characteristics of more expensive non-portable pumping systems such as pens and pen needles, syringes, or those employing guide screw drive mechanisms. According to the exemplary embodiments described herein, a novel nested telescopic screw design is employed, which enables the use of syringe-based drug containers or similar reservoirs that have proven to be drug-friendly or biocompatible with drugs and other fluids delivered via fluid delivery devices.

[0037] Figure 1 This is a perspective view of a wearable fluid delivery device 10 constructed according to an example embodiment. The drug delivery device 10 includes a base plate 12, a cover 14, and an insertion mechanism 16 in an undeployed position. The reservoir fluid delivery device 10 can be filled with fluid (e.g., a drug) by a user inserting the needle of a pre-filled syringe 36 into a filling port (not shown) provided in the base plate 12, which has an inlet fluid path from the filling port to the reservoir. It should be understood that the fluid delivery device 10 can be filled with fluid (e.g., a drug) using different mechanisms and methods.

[0038] Figure 2 yes Figure 1 A perspective view of the fluid delivery device, with the cover removed. A base plate 12 supports an insertion mechanism 16, a motor 18, a power source such as a battery 20, a control panel (not shown), and a reservoir 22 or container for storing fluid, which is delivered to the user via an outlet fluid path 24 from the reservoir's outlet port to the insertion mechanism 16. The reservoir 22 may also have an inlet port connected to a filling port (e.g., located in the base plate 12) via an inlet fluid path 26. The reservoir 22 includes a plunger 28 with a plug assembly 29. A plunger actuator assembly 30 is also provided at the proximal end of the reservoir 22, having a plurality of telescopic nested screws, a gear anchor 34, and an outermost drive screw 36, which is rotated by means of a gear train 38 connected to the motor 18. Although the gear train 38 is shown for illustrative purposes, the drive mechanism may be a gear, a ratchet, or other method of causing rotation from the motor.

[0039] Figure 3This is a block diagram of example components of a fluid delivery device constructed according to an exemplary embodiment. The cover / housing or housing of device 10 is indicated by 14. Device 10 has a skin-holding subsystem 40, such as an adhesive pad that attaches device 10 to a user's skin. The fluid delivery device 10 also includes a reservoir 22, an insertion mechanism 16, and a fluid shifting module 42, which may include a motor 18, a gear train 38, 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 module (e.g., battery 20) and an electrical module 50. The electrical module 50 includes a controller 52, a motor driver 54, an optional sensing module 56 for sensing fluid flow conditions (e.g., blockage or pump mechanism malfunction), an optional audio driver 58 (e.g., to indicate ongoing drug administration, reservoir depletion, blockage, successful pairing with an external device, or other conditions via an audible alarm such as a buzzer), an optional video driver 60 for providing visual feedback via (one or more) LEDs, and / or an optional tactile driver for providing tactile 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 dedicated controller 63). Regarding the sensing module 56, the fluid delivery device may, for example, be equipped with one or more encoders to provide feedback to the drive mechanism (e.g., plunger driver assembly 30) for indexing and preventing pump mechanism malfunction.

[0040] Figure 4A and Figure 4B These are top views and perspective views of the fluid delivery device, respectively. For clarity, the covering of the fluid delivery device has been removed to depict a plunger drive assembly constructed according to an example embodiment. The plunger drive assembly 30 is shown as... Figure 4A The middle completely retracts, while Figure 4B Fully extended. It should be understood that the motor 18 can control the plunger drive assembly 30 to incrementally move the telescopic screw member from the fully retracted position shown to the fully extended position shown, thereby delivering a corresponding specified dose of fluid from the fluid chamber portion 64 of the reservoir 22. The motor 18 and gear train 38 rotate the outermost drive screw 70 on the plunger drive assembly 30. The gear train 38 can have different configurations. For example, the gear train 38 can also be in the form of a ratchet indexing mechanism or other indexing mechanism that precisely rotates the drive nut or outermost drive screw 90 by a mechanically controlled amount. The motor 18 and the associated gear train components 38, as well as the outermost drive screw 70 of the plunger drive assembly 30, can be mounted relative to each other via a mounting plate 66 or other mechanism fixed to the base plate 12. The reservoir 22 can be fixed to the base plate 12 via a reservoir mounting (e.g., a wall on the base plate 12, mounting plate 66, an upper structure in the device housing 14, or other structure). Figure 4B As shown, the motor housing 44 fixes the motor 18 relative to the base plate 12, and the housing and the base plate can be integral components.

[0041] Continue to refer to Figure 4B An inlet fluid path is provided from a filling port (not shown) on the underside of the base plate 12 to an inlet port (not shown) of the reservoir 22, allowing the reservoir to be filled before shipment or by the user before using the fluid delivery device 10. A gear anchor 34 is located at the proximal end of the reservoir 22 and is stationary relative to the reservoir 22. A plunger 28 is disposed within the reservoir 22 and configured to be controllably translated along the longitudinal axis of the reservoir 22 by operation of the plunger drive assembly 30 and the motor 18.

[0042] Figure 5 A plunger actuator assembly 30 according to an example embodiment is shown. The plunger actuator assembly 30 includes a three-layer telescopic guide screw, comprising an outermost drive screw 70, a sleeve screw 72, and an innermost screw 74. The outermost drive screw 70 has a first portion having drive gear teeth 70a and a threaded orifice 70b. The drive gear teeth 70a cooperate with teeth on an adjacent gear of a gear train 38 actuated by a motor 18. The threaded orifice 70b cooperates with the external thread 72a of the sleeve screw 72. The sleeve screw 72 has an end feature 72b at its proximal end and a threaded orifice 72c at its distal end. The end feature 72b is used to prevent the sleeve screw 72 from being driven out of the outermost drive screw 70. The threaded orifice 72c has an internal thread that cooperates with the external thread 74a of the innermost screw 74. The innermost screw 74 has an end feature 74b at its proximal end and a keyed feature 74c at its distal end. The end feature 74b prevents the innermost screw 74 from being disengaged from the sleeve screw 72. The keyed feature 74c may be a selected shape, protrusion, or other feature or component that engages the innermost screw 74 with a cooperating keyed feature on the plunger 28, while restricting the innermost screw 74 from rotating relative to the plunger 28 when the outermost screw 70 is rotated by the motor 18 and gear train 38. In other words, when the outermost drive screw 70 is driven via the motor 18 and gear train 38, the distal end of the innermost screw 74 is anchored within the plunger 28 or other surface of the plunger driver assembly 30. Clockwise rotation of the outermost drive screw 70 advances the sleeve screw 72 and the innermost screw 74. For example, screw members 70, 72, and 74 have right-hand threads, but they can also be designed to have left-hand threads. For example, each of the screw elements 70, 72 and 74 has the same internal screw design and / or external screw design, with minor variations in the same pitch and other parameters.

[0043] According to one example embodiment, the length of the drive screw 70 is configured such that when all the individual screws are nested or retracted, they are all contained within the drive screw 70. Furthermore, the drive screw 70 is provided with a thrust bearing cap 98 at its proximal end to help the device 10 absorb axial thrust loads, as further described below.

[0044] According to another example embodiment, the pusher 80 is configured as a separate component between the inner screw 74 and the plunger 28. The pusher 80 may be provided with a keyed feature (e.g., 82) instead of the plunger 28 to receive a keyed protrusion or other feature 74c from the innermost screw 74, and its overall shape is adapted to prevent rotation of the innermost screw 74. One advantage of using the pusher 80 is that its design can reduce off-axis forces, which can negatively impact the accuracy of motion and overall volume delivery due to uncontrolled plunger oscillation.

[0045] The torque ratio between screws 72 and 74 is related to the diameter of each component, with the minimum drive torque associated with the smaller diameter of the innermost screw 74. Under optimal conditions, when rotation is restricted by the surface of plunger 28 or other surfaces or components to which it is anchored, the innermost or smallest screw 74 may be driven forward first. Next, the sleeve screw 72 begins to rotate and move forward. Manufacturing variations and tolerances may cause changes in the sequence of forward movements; however, the parts typically move forward only according to the common pitch of each part. In addition to the outermost drive screw 70 with drive gear teeth 70a, each inner screw will require an end feature to prevent the screw from being driven out of the assembly. This feature length can be minimized to minimize size. However, this feature will also help stabilize the axial movement of the screw and prevent non-axial oriented movement.

[0046] The innermost screw 74 requires a keyed feature to engage the plunger 28. This keyed feature can engage with a non-circular plunger geometry, thereby preventing rotation by geometry, or it can engage with an intermediate structure (e.g., the pusher 80) designed to prevent rotation within the operating syringe barrel. This end feature 74c is preferably smaller than the external thread of the same innermost screw 74, allowing it to be assembled from the rear end of assembly 30. For example, the dimensions and / or shape of the distal end of the innermost screw 74 can be configured to engage a correspondingly sized and / or shaped stop or recess 82 in the plunger 28 or pusher 80, preventing any rotation applied to the innermost screw 74 by other components 70 and 72 that would cause the plunger 28 to rotate relative to the inner wall of the reservoir 22. The keyed feature 74c on the distal end of the innermost screw is smaller than the thread, and its features and / or shape allow it to be pressed or securely engaged into the pusher to prevent relative rotation. If desired, other stronger, larger features can be attached to the front or distal end of the screw 74. This design can employ an elliptical syringe barrel-type reservoir 22 to contain the medication and provide anti-rotation functionality. The elliptical shape also has the potential additional benefit of saving device height. Furthermore, the telescopic nested guide screw design of the example embodiment can be supplemented by a suitable ratchet / indexing mechanism to further improve delivery resolution.

[0047] Figure 6A and Figure 6B Rear and front perspective views of the gear anchor 34 according to an exemplary embodiment are depicted. The gear anchor 34 is a disc-shaped member inserted into an opening at the proximal end of the reservoir 22, and may have optional features such as one or more protrusions 34a with slots 34d to facilitate press-fit or snap-fit ​​engagement with pins 66a on the reservoir mount. The gear anchor 34 has an aperture 34b and a lip 34c, the aperture 34b being sized to receive the distal end 70d of the outermost drive screw 70, which has a smaller circumference than the first portion 70a. The lip 34c cooperates with the distal end of the outermost drive screw 70 to secure the outermost drive screw 70 against the gear anchor 34. It should be understood that the lip or flange 34c can be removed to reduce the axial space occupied by the screw system. Its function is limited because typical loads act in the opposite direction to this surface. In an alternative arrangement, a ring may be added to the drive screw 70, which will be supported on the outer surface of the reservoir cover or gear anchor 34. The gear anchor 34 also has at least one orifice or through hole 34a for venting. As described below, the pusher 80 may also have one or more openings and / or gaps to allow venting as it moves axially within the reservoir 22.

[0048] Figure 7A, Figure 7B and Figure 7C Plunger 28 and plug assembly 29 according to an example embodiment are depicted, wherein pusher 80 is keyed to the innermost screw 74. It should be understood that plunger 28 or intermediate pusher 80 may include a disc-shaped member having a stop, notch, or other feature 82 cooperating with a keyed feature 74c at the distal end of the innermost screw 74 to prevent plunger 28 from rotating relative to the inner wall of reservoir 22 when the outermost drive screw 70 rotates within orifice 22b via motor 18 and gear train 34, and as a result, screw members 72 and 74 extend or retract translationally via the cooperation of their respective threads. It should be understood that plunger 28 may be separable from the screw, and intermediate member (e.g., pusher 80) provides anti-rotation functionality (e.g., providing a ball joint interface between the distal end of the innermost screw and the proximal end of pusher 80 to limit off-axis load transmission). Optional protrusions 81 on the front surface of pusher 80 may abut the rear surface of plunger 28. Figure 7A As shown, the protrusion 81 may be provided with an anti-rotation slot 81a. During assembly, the post on the distal end of the innermost screws 74, 96 may extend into the stop 90, through the pusher 80 and slightly beyond its protrusion 81. During the heat fusion of the innermost screws relative to the pusher 80, the post on the distal end of the innermost screws 74, 96 cooperates with the slot 81a. The pusher 80, together with or alternatively with the cover 34 on the reservoir 22, is provided with one or more features that allow air venting. For example, the air venting features may be provided along at least a portion of the periphery of the pusher 80 and may be in the form of a serrated edge including a notch 80a. When the notch 80a is provided on the periphery of the pusher 80, these features may be arranged to minimize axial translational friction by biasing the design and tolerances of the edges around some of these features 80a to be more prominent relative to the remaining notch edges, thereby preventing rotation upon initial contact with the inner reservoir cylinder surface. The pusher 80 may also have one or more through holes 80b for ventilation in the plate-like portion of the pusher.

[0049] The plunger 28 has a stopper assembly 29 to prevent leakage of any fluid retained in the fluid chamber portion 64 of the reservoir 22. The stopper assembly 29 may include, for example, an elastic member 84 comprising an elastic material similar to that of a syringe stopper and configured as a disc to be mounted to the surface of the plunger 28 disc, or as a strip of material configured to surround the plunger 28 disc. Alternatively, the plunger 28 may be configured to have one or more (e.g., two) circumferential grooves, the dimensions of which are adapted to accommodate corresponding O-rings. For example, using two O-rings increases stability (e.g., even with increased length). Depending on the dosage accuracy requirements, a single O-ring may be a feasible option; however, for high precision, two O-rings are particularly advantageous.

[0050] The configuration of the plunger driver assembly 30 relative to the reservoir 22 and plunger 28 offers several advantages. For example, mounting the plunger driver assembly 30 at the proximal end of the reservoir 22 and having a nested configuration that does not extend into the reservoir before the outermost drive screw is rotated optimizes the use of the reservoir chamber for fluid delivery, rather than requiring the plunger driver assembly to be housed before delivery. Furthermore, the overall length of the reservoir can be substantially the same as the length of the housing, adding a small amount of top space to accommodate the connection of the gear train 34 to the drive gear teeth 70a of the outermost drive screw 70. Therefore, the overall footprint of the pump mechanism and the longitudinal axial dimension of the fluid delivery device housing are minimized. The use of the plunger 28 and plunger driver assembly 30 design also minimizes the contact between the pump mechanism and the delivered fluid, ensuring biocompatibility between the fluid and the fluid delivery housing. The example embodiment described herein employs nested telescopic screws of appropriate size and thread configuration to achieve controlled movement of the syringe barrel-type reservoir plunger 28. Screw-thread technology has been well defined and understood and enables repeatable, powerful movements. When driven by motion controlled with appropriate resolution by motor 18, the nested screws (e.g., 72 and 74) can provide accurate movement under almost all environmental conditions. Furthermore, the drive mechanism (e.g., plunger driver assembly 30) does not affect the basic volume of the fluid chamber 64 containing the drug, and therefore does not cause any compatibility issues.

[0051] The technical solution of the example embodiment is based on a basic screw drive mechanism, where the lifting torque is a function of the applied axial load (force or pressure), thread pitch, friction parameters, and diameter. In some cases, the equation can be further extended to obtain full details of the thread geometry, such as tooth flanks and lead angles, as well as many other specific parameters. Industry-standard dimensions for ACME threads are generally used to balance lifting torque, required power, efficiency, and other functional parameters such as operational smoothness and cost. Other thread forms, such as sawtooth threads, can also be used to precisely control load transfer and minimize dosage errors. Each screw design can affect the torque; therefore, variations should be made to suit the capabilities of the motor and gearbox or indexing drive subsystem.

[0052] The design employed in this example embodiment allows it to be driven on a very small scale using a geared transmission. The torque required to move the gears is independent of the number of gears used in the system and is primarily influenced by the choice of material and geometry for the threads. Therefore, a small motor and low gearbox ratio can be used, resulting in a compact device 10. Conversely, the torque on each screw is different, with the innermost screw exhibiting the lowest torque and the outermost screw exhibiting the highest torque. The efficiency of the power transmission is affected by numerous interfaces that reduce overall efficiency, but these can be adjusted to acceptable levels using the adjusted parameters used in the equations to determine the desired increase in torque. In any case, if battery power or any other input power is readily available, this design has the potential to create highly accurate pumps for many drug treatments, unlike any type of medical drug delivery pump currently available.

[0053] Figure 8A and Figure 8B These are a top view and a perspective top view of the fluid delivery device. For clarity, the covering of the fluid delivery device has been removed to depict a plunger actuator assembly 30 with four telescopic guide screws constructed according to another example embodiment. The four telescopic guide screws include an outermost drive screw 90, a first sleeve screw 92, a second sleeve screw 94, and an innermost screw 96, as shown below. Figure 10 As illustrated in the diagram. The key 82 between the innermost screw 96 and the plunger 28 (or pusher 80) is similar to the embodiment described above using a three-layer telescopic lead screw. Reference Figure 10 The first sleeve screw 92, the second sleeve screw 94 and the innermost screw 96 each have end features at their proximal ends to prevent them from being driven from the plunger driver assembly 30 in which they are nested.

[0054] The aforementioned thrust bearing cap 98 can be snap-fitted or otherwise pressed into the proximal end of the external screw, but... Figure 8B It is shown as removed in [the text], while Figures 9A to 9C The image shows the item in place. For example... Figure 11 As illustrated in the figure, according to an example embodiment, the cover 98 has a raised boss 102 that interacts with the superstructure 66 supporting the reservoir, screw, and motor, or with a wall on the base plate 12 generally indicated by 100. This superstructure 66 or wall 100 absorbs or minimizes axial thrust loads and fluid pressures from the screw and possibly from the plunger O-rings, thereby helping to prevent loss of dosage accuracy. The small boss 102 on the cover 98 has a small diameter to minimize any additional torque applied to the drive system. The size of the boss 102 can be set large enough to avoid digging and abrading into the support wall, and material selection can contribute to this design. Since screw movement can cause the screw assembly 30 to be pushed backward, the thrust bearing cover 98 provides the benefit of handling these forces by distributing them over a sufficiently small area to reduce torque without damaging the support structure. Alternatively, the thrust can also be controlled at other locations on the drive screw or nut 70. For example, a slotted reservoir cover with a slot can be used with an alternative drive nut configuration having an outer ring that rotates within the slotted cover. The slotted cover may have a pressure pin that allows it to be assembled around the drive nut and then inserted into the reservoir.

[0055] Figures 4A to 4B and Figures 8A to 8B The two embodiments of the present invention respectively facilitate minimizing the internal storage space 22 used by the plunger driver assembly 30, thereby optimizing the volume of the fluid chamber 64, while minimizing the storage space occupied on the base plate, and thus minimizing the overall housing size. In both embodiments, the storage chamber 22 includes the volume occupied by the fluid chamber 64 and the plunger 28 and plug assembly 29, and the nominal storage volume is occupied by the plunger driver assembly 30 when the plunger driver assembly 30 is in its fully retracted position.

[0056] Figure 8A and Figure 8B The plunger driver assembly in Figure 9A In the fully retracted position, Figure 9B In the middle position, while Figure 9CThe plunger drive assembly 30 is in the fully extended position. It should be understood that the motor 18 can control the plunger drive assembly 30 to incrementally move from the fully retracted position to the fully extended position to deliver a specified dose of fluid from the fluid chamber portion 64 of the reservoir 22. Indexers and runaway prevention devices can be provided relative to the outermost drive screws 70, 90 to ensure controlled rotation of the screws 70, 90 by the motor, thereby preventing runaway of the pump mechanism. For example, the drive screws or nuts 70, 90 can be equipped with (one or more) encoders for indexing and accurate dose delivery, and to provide feedback to the electrical module 50 to further prevent runaway of the drive nut 70 or undesirable or inaccurate pump motor actuation and rotation.

[0057] Figures 8A to 10 The four-layer telescopic guide screw design has the following advantages: In conjunction with... Figures 4A to 5 The three-layer telescopic guide screw design, within the same axial footprint, can potentially extend further at the cost of a slightly larger diameter / lateral dimension. The embodiments described herein are applicable to two to four or more nested screws; that is, as many nested screws as are mechanically and electrically feasible. For example, a minimum of two layers can be used, and a maximum number of layers can be used, limited by dimensional constraints. As the number of telescopic nested screws increases, the efficiency of the design will decrease due to inherent losses at the screw thread interface. Ultimately, however, any of these designs can be advantageous, depending on the balance between dimensional constraints and available power.

[0058] This design is based on a basic screw drive mechanism, where the lifting torque is a function of the applied axial load (force or pressure), thread pitch, friction parameters, and diameter. In some cases, the equation can be further extended to obtain full details of the thread geometry, such as tooth flanks and lead angles, as well as many other special parameters. ACME threads are often used to balance lifting torque, required power, efficiency, and other functional parameters such as operational smoothness and cost.

[0059] There are no wearable disposable patch pumps using this type of mechanism. This is a novel use of a basic mechanism based on a wedge design, such as a screw. The novelty of this design lies in its significant space advantage, while trading for some mechanical losses. The space savings open up important design space for novel drug delivery pumps with high delivery accuracy potential. The design of the example embodiments of this disclosure can be supplemented with ratchet or indexing drive transmissions to further improve motion resolution, resulting in accurate drug delivery.

[0060] The example embodiments described herein employ an elliptical syringe barrel reservoir 22 to contain a drug or fluid to be delivered. The elliptical syringe barrel reservoir 22 provides anti-rotation functionality and associated benefits. For example, the anti-rotation provided by the inherent design of the elliptical syringe barrel reservoir 22 naturally prevents rotation of the barrel when torque is applied. The elliptical shape also has the added benefit of potentially saving overall device height. However, the same anti-rotation could be achieved using separate components. For example, the innermost screw could be keyed to a stop or other feature in the stopper assembly 28, or to a drive component or surface in the plunger drive assembly 30. Thus, even if the reservoir 22 is not elliptical (e.g., has a circular cross-section), prevention of rotation of the plunger drive assembly 30 relative to the inner wall of the reservoir 22 can still be achieved during axial translation.

[0061] The reservoir 22 may be constructed to be durable, i.e., it is not removable but pre-installed within the fluid delivery device housing 14. The reservoir 22 may be made of a material similar to a syringe barrel and its associated stopper. The reservoir 33 may be pre-filled, and the plunger drive assembly 30 is initially in the retracted position. Alternatively, the fluid delivery device housing 14 may be provided with a filling port and a fluid path 26 from the filling port to the reservoir 22. The filling port may be configured for filling by a user using a syringe or by using a filling station fluidly connected to the filling port.

[0062] Although various persons, including but not limited to patients or healthcare professionals, may operate or use the illustrative embodiments of this disclosure, for the sake of simplicity, the operator or user will be referred to as the “user” below.

[0063] Although various fluids may be used in the illustrative embodiments of this disclosure, for simplicity, the liquid in the injection device will be referred to as "fluid" below.

[0064] Those skilled in the art will understand that this disclosure is not limited in its application to the details of the construction and arrangement of the components set forth in the above description or illustrated in the accompanying drawings. The embodiments described herein can be other embodiments and can be practiced or performed in various ways. Moreover, it should be understood that the wording and terminology used herein are for descriptive purposes only and should not be considered limiting. The use of “comprising,” “including,” or “having,” and variations thereof herein is intended to include the items listed thereafter and their equivalents, as well as additional items. Unless otherwise limited, the terms “connection,” “linkage,” and “installation,” and variations thereof are used broadly herein and cover both direct and indirect connections, linkages, and installations. Furthermore, the terms “connection” and “linkage,” and variations thereof, are not limited to physical or mechanical connections or linkages. Additionally, terms such as upper, lower, bottom, and top are relative and used for illustrative purposes, not for limitation.

[0065] The components of the illustrative apparatus, systems, and methods employed according to the illustrated embodiments may be implemented at least partially in digital electronic circuit systems, analog electronic circuit systems, or in computer hardware, firmware, software, or combinations thereof. These components may be implemented, for example, as computer program products, such as computer programs, program code, or computer instructions tangibly embodied in an information carrier or machine-readable storage device, for execution or control of their operation by a data processing device such as a programmable processor, computer, or multiple computers.

[0066] The description and figures presented above are merely examples and are not intended to limit the illustrative embodiments in any way, except as set forth in the appended claims. In particular, those skilled in the art can readily combine various technical aspects of the various elements of the various illustrative embodiments 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 conveying device, comprising: A reservoir including an outlet port at a distal end and a plunger movable along a longitudinal axis of the reservoir, the plunger being configured to provide a seal relative to an inner wall of the reservoir to prevent fluid supplied 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; A plunger drive assembly is mounted at the proximal end of the reservoir and includes a plurality of nested telescopic screws, wherein when the outermost drive screw is rotated, the plurality of nested telescopic screws extend from a nested configuration not extending into the reservoir to an extended configuration extending from the proximal end of the reservoir into the reservoir. The plurality of nested telescopic screws include an innermost screw connected to the plunger and restricted from rotation by an anti-rotation mechanism. The anti-rotation mechanism includes a pusher disposed between the plunger and the distal end of the innermost screw, the pusher abutting against the proximal side of the plunger and configured to move along the longitudinal axis of the reservoir in response to rotation of the outermost screw. The storage container is a syringe-shaped container, and The pusher includes a keyed feature portion that cooperates with a corresponding keyed feature portion on the distal end of the innermost screw to engage the innermost screw with the pusher.

2. The fluid conveying device according to claim 1, wherein, The anti-rotation mechanism is a plunger and reservoir with a non-circular cross-section to prevent the plunger from rotating within the reservoir when the outermost drive screw is rotated.

3. The fluid conveying device according to claim 2, wherein, The reservoir and plunger each have an elliptical cross-section.

4. The fluid conveying device according to claim 1, wherein, The keyed feature of the pusher includes a stop, and the size and / or shape of the corresponding keyed feature on the distal end of the innermost screw is configured to be press-fitted into the stop of the corresponding size and / or shape.

5. The fluid conveying device according to claim 4, wherein, The stop includes a through hole leading to the distal side of the pusher, and the distal end of the innermost screw extends through the through hole.

6. The fluid conveying device according to claim 5, wherein, The distal end of the innermost screw is heat-fused at the through hole at the distal end of the pusher.

7. The fluid conveying device according to claim 6, wherein, The through-hole includes an anti-rotation slot.

8. The fluid conveying device according to claim 5, wherein, The pusher includes a protrusion on its distal side, and the through hole extends through the protrusion.

9. The fluid conveying device according to claim 1, wherein, The actuating element includes at least one through hole for ventilation.

10. The fluid conveying device according to claim 1, wherein, The pusher includes a notch for ventilation along at least a portion of its periphery.

11. The fluid conveying device according to claim 1, wherein, The anti-rotation mechanism includes a stop on the second side of the plunger, the stop being sized to cooperate with the distal end of the innermost screw to prevent the plunger from rotating relative to the inner wall of the reservoir when the outermost drive screw is rotated.

12. The fluid conveying device according to claim 11, wherein, The size and / or shape of the distal end of the innermost screw is configured to be press-fitted into a stop of a corresponding size and / or shape.

13. The fluid conveying device according to claim 1, wherein, The plurality of nested telescopic screws include an outermost drive screw having an inner diameter and internal thread size configured to receive a sleeve screw with an external thread, the external thread of the sleeve screw being configured to cooperate with the internal thread to cause the sleeve screw to move forward within the outermost drive screw when the outermost drive screw is rotated.

14. The fluid conveying device according to claim 13, wherein, The sleeve screw has an inner diameter and internal thread size configured to receive the innermost screw, the innermost screw having an external thread configured to cooperate with the internal thread of the sleeve screw to move the innermost screw forward within the sleeve screw as the sleeve screw rotates.

15. The fluid conveying device according to claim 14, wherein, The torque ratio of the innermost screw is less than that of the sleeve screw, and the torque ratio of the sleeve screw is less than that of the outermost drive screw, so that the innermost screw is allowed to extend into the reservoir along the sleeve screw when rotation is restricted before the sleeve screw begins to rotate relative to the outermost drive screw and move forward into the reservoir.

16. The fluid conveying device according to claim 1, wherein, The multiple nested telescopic screws have right-hand threads and corresponding internal and external screw parameters with the same pitch.

17. The fluid conveying device according to claim 1, wherein, The multiple nested telescopic screws have left-hand threads and corresponding internal and external screw parameters with the same pitch.

18. The fluid conveying device according to claim 1, wherein, The reservoir also includes a gear anchor mounted to its proximal end, the gear anchor including an orifice sized to receive the distal end of the outermost drive screw and allowing the nested telescopic screws to extend into the reservoir when the outermost drive screw is rotated.

19. The fluid conveying device according to claim 18, wherein, The gear anchor is disc-shaped and sized to be press-fitted into the proximal end of the reservoir.

20. The fluid conveying device according to claim 18, wherein, The gear anchor includes a through hole for ventilation.

21. The fluid conveying device according to claim 18, wherein, The orifice in the gear anchor is configured to provide stable support to the outermost drive screw while allowing the outermost drive screw to be rotated relative to the gear anchor.

22. The fluid conveying device according to claim 18, wherein, When the plunger driver assembly is in its nested configuration, the distal end of the innermost screw is flush with the distal end of the gear anchor.

23. The fluid conveying device according to claim 18, wherein, When the plunger driver assembly is in its nested configuration, the distal end of the innermost screw protrudes from the distal end of the gear anchor by a specified length, the specified length corresponding to the depth of a stop provided on the second side of the plunger or on an intermediate pusher located between the plunger and the distal end of the innermost screw.

24. The fluid delivery device of claim 1, further comprising a thrust bearing feature disposed relative to the plunger driver assembly and a support structure for the plunger driver assembly to minimize axial thrust loads from the plurality of nested telescopic screws.

25. The fluid conveying device according to claim 24, wherein, The thrust bearing feature includes a cover disposed on the outermost drive screw, the cover having a boss for contacting a portion of the support structure to resist axial thrust loads directed toward the proximal end of the plunger drive assembly and generated by the plunger drive assembly, the plunger, or fluid in the fluid chamber.

26. The fluid delivery device of claim 1, further comprising an encoder disposed relative to the plunger driver assembly for generating feedback data related to the operation of the plunger driver assembly.

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