Multiple telescoping screw-driven pump mechanism with Anti-rotation of innermost screw keyed to reservoir plunger in fluid delivery device

Abstract

To provide a fluid delivery device that realizes small size, low power consumption, accurate delivery, high reliability, and low manufacturing cost.SOLUTION: A fluid delivery device has a syringe barrel-type reservoir with a plunger and a plunger driver assembly comprising nested, telescopic screws comprising an innermost screw keyed to a first side of the plunger or an intermediate pusher to prevent rotation. In a fully retracted position, the nested screws do not extend into the reservoir. The nested screws employ the same pitch in their respective inner thread and outer thread designs. The decreasing torque ratios from the outermost to innermost screw members and anti-rotation feature allow the innermost screw to advance the plunger into the reservoir before the adjacent concentric screw member commences rotating and advancing within its corresponding screw and to translate the plunger and expel fluid in a fluid chamber defined on the other, second side of the plunger.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No. 63 / 066,851, filed August 18, 2020, the contents of which are incorporated herein by reference in their entirety.

[0002] Exemplary embodiments generally relate to a pump mechanism for use in a fluid delivery device such as a wearable drug infusion patch. Exemplary embodiments generally relate to a telescoping screw for controllably extending or retracting a plunger drive in a syringe barrel-type reservoir, which does not affect the reservoir volume to ensure biocompatibility, is completely retractable outside the reservoir, and is keyed to the plunger to prevent rotation. [Background technology]

[0003] The design of a typical drug delivery patch pump requires compact size, low power consumption, accurate delivery, high reliability, and low manufacturing costs. Furthermore, the design of a drug delivery patch pump must not compromise the quality of the drug. For example, the materials used for the pump mechanism components that come into contact with the delivered fluid must be biocompatible. Summary of the Invention [Problem to be solved by the invention]

[0004] The above-mentioned problems and other issues are overcome, and further advantages are realized, by the illustrative embodiments. [Means for solving the problem]

[0005] Exemplary embodiments of the present disclosure achieve several advantages, such as minimizing the envelope or form factor of the device size while retaining the beneficial features of reliable and proven systems such as medication pens and pen needles, syringes, or more expensive non-portable pump systems that employ lead screw drive mechanisms.

[0006] In accordance with an aspect of the exemplary embodiments, an improved and novel telescoping screw design is provided that allows for the use of syringe barrel-type drug containers or similar reservoirs that have proven drug-compatible or biocompatible with the drugs and other fluids to be delivered via the fluid delivery device.

[0007] According to aspects of an exemplary embodiment, a fluid delivery device is provided that includes a reservoir including an outlet port at a distal end and a plunger movable along a longitudinal axis of the reservoir. The plunger is configured to provide a seal against an interior wall of the reservoir to prevent fluid provided in a fluid chamber defined by a first side of the plunger and constituting the outlet port from leaking into a portion of the reservoir defined by a second side of the plunger. The fluid delivery device also includes a plunger drive assembly attached to the proximal end of the reservoir, the plunger drive assembly comprising a plurality of telescoping screws that, upon rotation of an outermost drive screw, move from a nested configuration that does not extend into the reservoir to an extended configuration that extends into the reservoir from the proximal end of the reservoir. The plurality of telescoping screws comprises an innermost screw coupled to the plunger and restrained from rotation by an anti-rotation mechanism.

[0008] According to an aspect of the exemplary embodiment, the reservoir is a syringe barrel type container.

[0009] According to an aspect of the exemplary embodiment, the anti-rotation mechanism is a reservoir and plunger having a non-circular cross-section to prevent rotation of the plunger within the reservoir when the outermost drive screw is rotated, for example, the reservoir and plunger each having an oval-shaped cross-section.

[0010] According to aspects of the exemplary embodiment, the anti-rotation mechanism includes a pusher disposed between the plunger and the distal end of the innermost screw, the pusher abutting 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.

[0011] According to aspects of the exemplary embodiment, the pusher includes a keying mechanism that cooperates with a corresponding keying mechanism on the distal end of the innermost screw to engage the innermost screw with the pusher. For example, the keying mechanism on the pusher comprises a detent, and the corresponding keying mechanism on the distal end of the innermost screw is sized and / or shaped to be press-fit into a detent of corresponding size and / or shape. Furthermore, the detent can define a through-hole distal to the pusher, and the distal end of the innermost screw can, for example, extend through the through-hole. The distal end of the innermost screw can be heat-stakingly secured to the through-hole distal to the pusher. The through-hole can define an anti-rotation groove to facilitate heat-staking. Alternatively, the pusher can define a protrusion on its distal side, and the through-hole can extend through the protrusion. According to another aspect, the pusher can include at least one through-hole for ventilation and / or a recess along at least a portion of its circumference for ventilation.

[0012] According to aspects of the exemplary embodiment, the anti-rotation mechanism comprises a detent on a second side of the plunger sized to cooperate with a 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-fit into a detent of corresponding size and / or shape.

[0013] According to an aspect of an exemplary embodiment, the plurality of telescoping screws includes an outermost drive screw having an inner diameter and inner threads sized to receive a sleeve screw having outer threads configured to cooperate with the inner threads to advance the sleeve screw within the outermost drive screw when the outermost drive screw is rotated.

[0014] In accordance with aspects of the exemplary embodiment, the sleeve screw has an inner diameter and internal threads sized to receive the innermost threads, the innermost threads having external threads configured to cooperate with the internal threads of the sleeve screw to advance the innermost thread within the sleeve screw when the sleeve screw is rotated.

[0015] According to aspects of an exemplary embodiment, the torque ratio of the innermost screw is less than the torque ratio of the sleeve screw, which is less than the torque ratio of the outermost drive screw to allow the rotationally constrained innermost screw to extend along the sleeve screw into the reservoir before the sleeve screw begins to rotate relative to the outermost drive screw and advances into the reservoir.

[0016] In accordance with an aspect of the exemplary embodiment, the plurality of telescopic screws have right-hand threads and internal and external thread parameters each employing the same pitch, or alternatively, the plurality of telescopic screws have left-hand threads and internal and external thread parameters each employing the same pitch.

[0017] According to aspects of the exemplary embodiment, the reservoir further comprises a gear anchor attached to its proximal end, the gear anchor including an opening dimensioned to receive the distal end of the outermost drive screw and allow the telescopic screw to extend into the reservoir when the outermost drive screw is rotated. For example, the gear anchor may be disk-shaped and dimensioned to be press-fit into the proximal end of the reservoir. For example, the opening in the gear anchor may be configured to provide stable support for the outermost drive screw while allowing the outermost drive screw to rotate relative to the gear anchor. Additionally, the gear anchor may be provided with a through-hole for ventilation.

[0018] According to an aspect of the exemplary embodiment, when the plunger drive assembly is in its nested configuration, the distal end of the innermost screw is flush against the distal side of the gear anchor.

[0019] According to aspects of the exemplary embodiment, 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 a predetermined length corresponding to the depth of a detent provided on either the second side of the plunger or an intermediate pusher between the plunger and the distal end of the innermost screw.

[0020] According to aspects of the exemplary embodiment, the fluid delivery device includes a thrust bearing mechanism provided for the plunger drive assembly and a support structure for the plunger drive assembly that minimizes axial thrust loads from the expansion screws. For example, the thrust bearing mechanism can be a cap disposed on the outermost drive screw, the cap having a boss facing the proximal end of the plunger drive assembly and contacting a portion of the support structure to resist axial thrust loads generated by the plunger drive assembly, the plunger, or fluid in the fluid chamber.

[0021] Additional and / or other aspects and advantages of the exemplary embodiments will be set forth in, or will be obvious from, the description that follows, or may be learned by practice of, the exemplary embodiments. The exemplary embodiments may include apparatuses and methods for similar operation having one or more of the above-described aspects and / or one or more of the features or combinations thereof. The exemplary embodiments may include, for example, one or more features and / or combinations of the above-described aspects as set forth in the appended claims. [Brief explanation of the drawings]

[0022] The above and / or other aspects and advantages of embodiments of the present invention will be more readily understood from the following detailed description taken in conjunction with the accompanying drawings. [Figure 1] FIG. 1 is a perspective view of a wearable fluid delivery device constructed in accordance with an exemplary embodiment. [Figure 2] 2 is a perspective view of the fluid delivery device of FIG. 1 with the cover removed. [Figure 3]FIG. 3 is a block diagram of exemplary components of a fluid delivery device configured in accordance with an exemplary embodiment. [Figure 4A] FIG. 4A is a top view of a fluid delivery device with the cover removed to clearly depict a plunger drive assembly constructed in accordance with an exemplary embodiment. [Figure 4B] FIG. 4B is a top perspective view of a fluid delivery device with the cover removed to clearly depict a plunger drive assembly constructed in accordance with an exemplary embodiment. [Figure 5] FIG. 5 illustrates a plunger drive assembly constructed in accordance with an exemplary embodiment and including a three-tiered telescoping lead screw design. [Figure 6A] FIG. 6A shows a rear perspective view of a gear anchor according to an exemplary embodiment. [Figure 6B] FIG. 6B illustrates a front perspective view of a gear anchor according to an exemplary embodiment. [Figure 7A] FIG. 7A shows a pusher assembly configured to be keyed to the innermost telescoping screw, according to an exemplary embodiment. [Figure 7B] FIG. 7B shows a pusher assembly configured to be keyed to the innermost telescoping screw, according to an exemplary embodiment. [Figure 7C] FIG. 7C shows a plunger stopper configured to be keyed to the innermost telescoping screw, according to an exemplary embodiment. [Figure 8A] FIG. 8A is a top view of a fluid delivery device with the cover removed to clearly depict a plunger drive assembly constructed in accordance with another exemplary embodiment employing a four-layer telescoping lead screw design. [Figure 8B] FIG. 8B is a top perspective view of a fluid delivery device with the cover removed to clearly depict a plunger drive assembly constructed in accordance with another exemplary embodiment employing a four-layer telescoping lead screw design. [Figure 9A] FIG. 9A shows the position of the plunger drive assembly of FIGS. 8A and 8B. [Figure 9B]FIG. 9B shows the position of the plunger drive assembly of FIGS. 8A and 8B. [Figure 9C] FIG. 9C shows the position of the plunger drive assembly of FIGS. 8A and 8B. [Figure 10] FIG. 10 illustrates a plunger drive assembly constructed in accordance with an exemplary embodiment and consisting of a four-layer telescoping lead screw design. [Figure 11] FIG. 11 is a partial side view of a fluid delivery device configured in accordance with an exemplary embodiment with an axial thrust bearing mechanism.

[0023] Throughout the drawings, like reference numerals will be understood to refer to like elements, features, and structures. DETAILED DESCRIPTION OF THE INVENTION

[0024] As will be understood by those skilled in the art, there are numerous ways to implement the implementation, improvement, and arrangement of the pump according to the embodiments disclosed herein. Although reference will be made to the exemplary embodiments shown in the drawings and the following description, the embodiments disclosed herein do not exhaustively cover the various alternative designs and embodiments encompassed by the disclosed technical solutions, and those skilled in the art will readily understand that various modifications may be made and various combinations may be made that deviate from the scope of the disclosed technical solutions.

[0025] Exemplary embodiments of the present disclosure achieve several advantages, such as minimizing the device size envelope or form factor while retaining the beneficial features of reliable and proven systems such as medication pens and pen needles, syringes, or more expensive non-portable pump systems that employ lead screw drive mechanisms. In accordance with exemplary embodiments described herein, a novel telescoping screw design is employed that allows for the use of syringe-based drug containers or similar reservoirs that have proven drug-compatible or biocompatible with the drugs and other fluids to be delivered via the fluid delivery device.

[0026] 1 is a perspective view of a wearable fluid delivery device 10 configured in accordance with an exemplary embodiment. The drug delivery device 10 includes a base plate 12, a cover 14, and an insertion mechanism 16 in an inactive position. The reservoir fluid delivery device 10 can be filled with a fluid (e.g., a medication) by a user inserting the needle of a pre-filled syringe 36 into a fill port provided in the base plate 12, which has an inlet fluid pathway from the fill port to the reservoir. It should be understood that the fluid delivery device 10 can be filled with a fluid (e.g., a medication) using different mechanisms and methods.

[0027] FIG. 2 is a perspective view of the fluid delivery device of FIG. 1 with the cover removed. The base plate 12 supports the insertion mechanism 16, the motor 18, a power source such as a battery 20, a control board (not shown), and a reservoir 22 or container that stores fluid to be delivered to a user via an outlet fluid pathway 24 from the reservoir's outlet port to the insertion mechanism 16. The reservoir 22 can also have an inlet port connected to a fill port (e.g., provided in the base plate 12) via an inlet fluid pathway 26. The reservoir 22 includes a plunger 28 with a stopper assembly 29. The proximal end of the reservoir 22 also includes a plunger drive assembly 30 having a plurality of telescoping telescoping screws, a gear anchor 34, and an outermost drive screw 36 that is rotated via a gear train 38 connected to the motor 18. While the gear train 38 is shown for illustrative purposes, the drive mechanism can be gears, ratchets, or other methods of inducing rotation from the motor.

[0028] 3 is a block diagram of exemplary components of a fluid delivery device configured in accordance with an exemplary embodiment. The cover / housing or housing of device 10 is indicated at 14. Device 10 has a skin retention subsystem 40, such as an adhesive pad, for connecting device 10 to a user's skin. Fluid delivery device 10 further comprises a reservoir 22, an insertion mechanism 16, and a fluid transfer module 42, which may include a motor 18, a gear train 38, a pumping mechanism (e.g., plunger drive assembly 30), and an outlet path 24. The fluid delivery device further comprises an electrical module 50, such as a power module (e.g., battery 20), a controller 52, a motor driver 54, an optional sensing module 56 for sensing fluid flow conditions (e.g., occlusion or runaway pump mechanism), an optional auditory driver 58 (e.g., for indicating in-dosing, low reservoir, occlusion, successful pairing with an external device, or other conditions via an audible alarm such as a buzzer), an optional visual driver 60 for providing visual feedback via light-emitting diode(s) and / or an optional tactile driver for providing tactile feedback via a vibration component, and an optional wireless driver 62 for wireless communication between the fluid delivery device and any remote pump control device (e.g., a smartphone or dedicated controller 63). In relation to the sensing module 56, the fluid delivery device can include one or more encoders to provide feedback of the drive mechanism (e.g., plunger drive assembly 30), for example, for indexing and pump mechanism runaway prevention purposes.

[0029] 4A and 4B are top and top perspective views of a fluid delivery device with the cover removed for clarity to depict a plunger driver assembly constructed in accordance with an exemplary embodiment. The plunger drive assembly 30 is shown in a fully retracted position in FIG. 4A and a fully extended position in FIG. 4B. It will be appreciated 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 a fully extended position to deliver each designated 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 be in the form of a ratchet indexing mechanism or other indexing mechanism that precisely rotates the drive nut or outermost drive screw 90 a mechanically controlled amount. The motor 18 and associated gear train components 38 and outermost drive screw 70 of the plunger drive assembly 30 may be attached to one another via a mounting plate 66 secured to the base plate 12 or other mechanism. The reservoir 22 may be secured to the base plate 12 via a reservoir mount (e.g., a wall on the base plate 12, the mounting plate 66, a superstructure within the device housing 14, or other structure). As shown in FIG. 4B, a motor housing 44 secures the motor 18 to the base plate 12, and the housing and base plate may be an integral part.

[0030] 4B, an inlet fluid pathway can be provided from a fill port (not shown) on the underside of base plate 12 to an inlet port (not shown) in reservoir 22 to allow a user to fill the reservoir prior to shipping or using fluid delivery device 10. A gear anchor 34 is provided at the proximal end of reservoir 22 and is stationary relative to reservoir 22. A plunger 28 is provided within reservoir 22 and configured to controllably translate along the longitudinal axis of reservoir 22 by operation of plunger drive assembly 30 and motor 18.

[0031] 5 illustrates a plunger drive assembly 30 according to an exemplary embodiment, including a three-layer telescoping lead screw consisting of an outermost drive screw 70, a sleeve screw 72, and an innermost screw 74. The outermost drive screw 70 has a first portion with drive gear teeth 70a that cooperate with adjacent gear teeth of the gear train 38 actuated by the motor 18 and a threaded opening 70b that cooperates with the external threads 72a of the sleeve screw 72. The sleeve screw 72 has an end feature 72b at its proximal end to prevent the sleeve screw 72 from being driven from the outermost drive screw 70, and a threaded opening 72c at its distal end with internal threads that cooperate with the external threads 74a of the innermost screw 74. The innermost screw 74 has an end feature 74b at its proximal end to prevent the innermost screw 74 from being driven from the sleeve screw 72, and a keying feature 74c at its distal end. The keying feature 74c may be a selected shape or protrusion, or other feature or component, that couples the innermost screw 74 to a cooperating keying feature on the plunger 28 while constraining 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 secured within the plunger 28 or other surface of the plunger drive assembly 30. The outermost drive screw 70 rotates clockwise, advancing the sleeve screw 72 and the innermost screw 74. The threaded members 70, 72, and 74 are, for example, right-hand threaded, but could all be designed to be left-hand threaded. For example, the threaded members 70, 72, and 74 each have the same internal and / or external thread design with the same pitch and slight variations in other parameters.

[0032] According to an exemplary embodiment, the length of drive screw 70 is dimensioned so that when the screws are all telescoping or folded, they are all contained within drive screw 70. Additionally, drive screw 70 includes a thrust bearing cap 98 at its proximal end to help device 10 absorb axial thrust loads, as further described below.

[0033] According to another exemplary embodiment, a pusher 80 is provided as a separate component between the inner threads 74 and the plunger 28. The pusher 80 may provide a keying feature (e.g., 82) in place of the plunger 28 to receive a keying protrusion or other feature 74c from the innermost threads 74 and is generally shaped to prevent rotation of the innermost threads 74. An advantage of using a pusher 80 is that its design can be adapted to reduce off-axis forces that could otherwise be adversely affected by uncontrolled plunger wobble, adversely affecting movement accuracy and overall volume delivery.

[0034] The torque ratio between the threads 72 and 74 is related to the diameter of each part, with the smallest drive torque associated with the smaller diameter of the innermost thread 74. Under optimal conditions, if rotation is constrained by the surface of the plunger 28 or another surface or member to which it is secured, the innermost or smallest thread 74 will likely drive forward first. Then, the sleeve thread 72 will begin to rotate and advance. Due to manufacturing variations and tolerances, the order of the payout motion may vary, but typically each part will only pay out according to the common pitch. With the exception of the outermost drive screw 70, which has the drive gear teeth 70a, each internal thread will require an end mechanism to prevent the screw from being expelled from the assembly package. The length of this mechanism can be minimized to minimize size. However, this mechanism also helps stabilize the axial movement of the screw and prevent non-axial movement.

[0035] The innermost threads 74 require a keying feature to engage the plunger 28. This keying feature can either engage with a non-circular cross-sectional plunger shape, thereby geometrically preventing rotation, or it can engage with an intermediate feature (e.g., pusher 80) that acts to prevent rotation within the syringe barrel during operation. This end feature 74c is optimally smaller than the outer threads of the same innermost threads 74 to allow assembly from the rear end of the assembly 30. For example, the distal end of the innermost threads 74 can be sized and / or shaped to engage a correspondingly sized and / or shaped detent or recess 82 on the plunger 28 or pusher 80, which prevents any rotation imparted to the innermost threads 74 by the other components 70 and 72 from causing rotation of the plunger 28 relative to the interior wall of the reservoir 22. The keying feature 74c at the distal end of the innermost screw is smaller than the screw and has features and / or shapes that compress or tightly engage with the pusher to prevent relative rotation. If desired, other stronger, larger features can be attached to the forward or distal end of the screw 74. This design can employ an oval-shaped syringe barrel-type reservoir 22 to contain the medication and provide anti-rotation functionality. The oval shape also has the added benefit of potentially reducing the height of the device. Furthermore, the telescoping, telescopic lead screw design of the exemplary embodiment can be complemented with an appropriate ratchet / indexing mechanism to further improve delivery resolution.

[0036] 6A and 6B show rear and front perspective views, respectively, of an exemplary embodiment of a gear anchor 34. The gear anchor 34 is a disk-shaped member inserted into an opening at the proximal end of the reservoir 22 and may have optional features, such as a protrusion 34a with a slot 34d to facilitate a press fit or snap fit over a pin 66a on the reservoir. The gear anchor 34 includes an opening 34b sized to receive the distal end 70d of the outermost drive screw 70, which has a smaller circumference than the first portion 70a, and a lip 34c that cooperates with the distal end of the outermost drive screw 70 to secure the outermost drive screw 70 to the gear anchor 34. It should be understood that the lip or flange 34c can be removed to reduce the axial footprint of the thread train. Its function is limited because typical loads react in an opposite direction to the surface. In an alternative arrangement, a ring can be added to the drive screw 70 to bear against the reservoir cap or the outer surface of the gear anchor 34. The gear anchor 34 also has at least one vent opening or through-hole 34a. As described below, the pusher 80 can also have opening(s) and / or gaps to allow venting as it moves axially within the reservoir 22.

[0037] 7A, 7B, and 7C show plunger 28 and stopper assembly 29, respectively, having a pusher 80 keyed to innermost screw 74, according to an exemplary embodiment. It will be appreciated that plunger 28 or intermediate pusher 80 may comprise a disk-like member having a detent, recess, or other feature 82 that cooperates with keying feature 74c on the distal end of innermost screw 74 to prevent rotation of plunger 28 relative to the inner wall of reservoir 22 when outermost drive screw 70 is rotated within opening 22b by motor 18 and gear train 34, such that threaded members 72 and 74 translate and extend / retract through cooperation of their respective threads. It will be appreciated that plunger 28 can be disengaged from the screws, with the intermediate member (e.g., pusher 80) providing an anti-rotation feature (e.g., a ball-joint interface between the distal end of the innermost screw and the proximal side of pusher 80 to limit off-axis load transfer). An optional protrusion 81 on the front face of the pusher 80 can be pressed into the rear face of the plunger 28. As shown in FIG. 7A , the protrusion 81 can be provided with an anti-rotation groove 81 a. When assembled, a post on the distal end of the innermost screw 74, 96 can extend through the pusher 80, slightly beyond the protrusion 81, and into the detent 90. The post on the distal end of the innermost screw 74, 96 cooperates with the groove 81 a during heat staking of the innermost screw to the pusher 80. The pusher 80 can include, in conjunction with or alternatively to the cap 34 on the reservoir 22, a feature or features for allowing venting. For example, the air vent feature can be in the form of a scalloped edge consisting of cutouts 80 a along at least a portion of the circumference of the pusher 80. If the pusher 80 has cutouts 80a on its outer periphery, these features can be designed and toleranced to minimize axial translational friction by raising the edges around some of these formations 80a above the remaining cutout edges so that they first contact the internal reservoir barrel surface to prevent rotation. The pusher 80 can also have one or more vent holes 80b in the plate-like portion of the pusher.

[0038] The plunger 28 includes a stopper assembly 29 for preventing leakage of any fluid held in the fluid chamber portion 64 of the reservoir 22. The stopper assembly 29 may be configured with a resilient member 84, for example, made of a resilient material similar to that of a syringe stopper, configured as a disk attached to the surface of the disk of the plunger 28 or as a strip of material surrounding the disk of the plunger 28. Alternatively, the plunger 28 may be configured with one or more (e.g., two) circumferential grooves sized to accommodate respective O-ring(s). For example, using two O-rings provides improved stability (e.g., at a greater length). Depending on the required dosage accuracy, a single O-ring may be sufficient, although two O-rings are particularly effective when high accuracy is required.

[0039] The configuration of the components of the plunger drive assembly 30 relative to the reservoir 22 and plunger 28 provides many advantages. For example, a plunger drive assembly 30 with a telescoping configuration that is attached to the proximal end of the reservoir 22 and does not extend into the reservoir until the outermost drive screw is rotated eliminates the need to accommodate plunger drive components prior to delivery, optimizing the use of the reservoir chamber for fluid delivery. Furthermore, the overall length of the reservoir can be substantially the same as the length of the housing, plus a small amount of headspace to accommodate the connection of the gear train 34 to the drive gear teeth 70a of the outermost drive screw 70. Thus, the overall footprint of the pump mechanism is minimized, as is the longitudinal axis dimension of the fluid delivery device housing. The use of the plunger 28 and plunger drive assembly 30 is also designed to minimize contact between the pump mechanism and the delivered fluid to ensure biocompatibility between the fluid and the fluid delivery housing. The exemplary embodiments described herein employ telescoping screws of appropriate size and thread configuration to achieve controlled movement of the syringe-barrel-shaped reservoir plunger 28. The screw technology is well-defined and understood, allowing for repeatable, powerful motion. When driven by motor 18 with controlled motion and adequate resolution, the telescoping screws (e.g., 72 and 74) can provide precise motion under virtually all environmental conditions. Furthermore, the drive mechanism (e.g., plunger drive assembly 30) does not affect the base volume of fluid chamber 64 where the drug resides, thereby avoiding any compatibility issues.

[0040] The technical solution of the example embodiment is based on a basic screw drive mechanism in which lifting torque is a function of applied axial load (force or pressure), thread pitch, friction parameters, and diameter. In some cases, the equations can be further expanded to incorporate thread profile details such as flank and lead angles, as well as many other specialized parameters. Industry-standard ACME thread sizes can generally be used to balance lifting torque, power requirements, efficiency, and other functional parameters such as smoothness of operation and cost. Other thread profiles, such as buttress threads, can also be used to precisely control load transfer and minimize dosing errors. Each screw design can affect torque, so modifications must be made to match the capabilities of the motor and gearbox or indexing drive subsystem.

[0041] The design employed by the illustrative embodiment is suitable for driving gear reduction transmissions on a very small scale. The torque required to drive the gears is independent of the number of gears used in the system and is primarily influenced by the material and shape of the screws. This allows for the use of small motors and low transmission reduction ratios, resulting in a compact device 10. Conversely, the torque varies with each screw, with the innermost screw producing less torque and the outermost screw producing more torque. The efficiency of the power transmission is affected by numerous interfaces, reducing overall efficiency, but can be adjusted to an acceptable level using adjustment parameters in the equation that determines the desired thrust torque. However, with abundant battery or other input power, this design has the potential to create a high-precision pump for many drug therapies, unlike current medical drug delivery pumps.

[0042] 8A and 8B are top and top perspective views of a fluid delivery device with the cover removed to clearly depict a plunger drive assembly 30 constructed according to another exemplary embodiment employing a four-layer telescoping lead screw including an outermost drive screw 90, a first sleeve screw 92, a second sleeve screw 94, and an innermost screw 96, as shown in FIG. 10. The keying 82 between the innermost screw 96 and the plunger 28 (or pusher 80) is similar to the above-described embodiment employing a three-layer telescoping lead screw. Referring to FIG. 10, the first sleeve screw 92, the second sleeve screw 94, and the innermost screw 96 each have an end feature at their proximal end to prevent them from being driven from the plunger drive assembly 30 in which they are nested.

[0043] The aforementioned thrust bearing cap 98, which can be press-fit onto the proximal end of the external threads, such as by a snap fit, is shown removed in FIG. 8B and in place in FIGS. 9A-9C. According to an exemplary embodiment, as shown in FIG. 11 , the cap 98 has a raised boss 102 that interacts with either the superstructure 66 supporting the reservoir, screw, and motor, or a wall, generally designated 100, on the base plate 12. This superstructure 66 or wall 100 helps absorb or minimize axial thrust loads from the screw, and possibly the plunger O-ring, and fluid pressure, thereby preventing loss of dose accuracy. The small boss 102 on the cap 98 has a small diameter to minimize additional torque imposed on the drivetrain. The boss 102 can be sized large enough to avoid digging into or wearing down the support wall, and material selection can aid in this design. Because screw movement can force the screw assembly 30 backward, the thrust bearing cap 98 offers the advantage of distributing these forces over a small enough area to reduce torque without damaging the supporting structure. Alternatively, thrust loads can be controlled elsewhere on the drive screw or nut 70. For example, a split reservoir cap could employ a slotted, alternate drive nut configuration with an outer ring that rotates within the split cap. The split cap could have a press pin that allows it to be assembled around the drive nut and inserted into the reservoir.

[0044] 4A-4B and 8A-8B are advantageous because they minimize the internal reservoir 22 space used by the plunger drive assembly 30, thereby optimizing the fluid chamber 64 volume, while simultaneously minimizing the reservoir footprint on the base plate and therefore the overall housing size. In both embodiments, the reservoir chamber 22 consists of the fluid chamber 64 and the volume taken up by the plunger 28 and stopper assembly 29, with the nominal reservoir volume taken up by the plunger drive assembly 30 when in the fully retracted position.

[0045] The plunger drive assembly of FIGS. 8A and 8B is shown in a fully retracted position in FIG. 9A, an intermediate position in FIG. 9B, and a fully extended position in FIG. 9C. It will be appreciated that the motor 18 can be controlled to move the plunger drive assembly 30 incrementally from the fully retracted position shown to the fully extended position to deliver a specified dose of fluid from the fluid chamber portion 64 of the reservoir 22. An intermittent indexing and runaway protection device can be provided for 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 and nuts 70, 90 can be equipped with encoder(s) for indexing and precise dose delivery, providing feedback to the electronics module 50 to further protect against runaway or undesired or inaccurate pump motor operation and drive nut 70 rotation.

[0046] The four-layer telescoping leadscrews of FIGS. 8A-10 have the same axial footprint as the three-layer telescoping leadscrews of FIGS. 4A-5, but have the advantage of being slightly larger in diameter / cross-sectional dimension, but with additional travel. The embodiments described herein can be adapted to work with anything from two telescoping threads to four or more telescoping threads, or as many as mechanically and electrically feasible. For example, a minimum of two layers can be used, with the maximum number of layers driven by size limitations. As the number of telescoping leadscrews increases, the efficiency of the design decreases due to losses that occur at the thread interfaces. However, ultimately, any of these designs may be beneficial, depending on the balance between size constraints and available power.

[0047] The upthrust torque is based on a basic screw drive mechanism, which is a function of axial load (force or pressure), thread pitch, friction parameters, and diameter. In some cases, the equations can be further expanded to incorporate details of the thread geometry, such as flank angle, lead angle, and many other specific parameters. ACME threads can generally be used to balance upthrust torque, power required, efficiency, and other functional parameters such as smoothness of operation and cost.

[0048] No wearable disposable patch pumps using such a mechanism exist. This is a novel use of a basic mechanism based on a wedge design such as a screw. The novelty of this design is that it offers significant space advantages while trading off some mechanical losses. This space saving significantly expands the design space for new drug delivery pumps with the potential for high delivery accuracy. The design of the exemplary embodiments of the present disclosure can be complemented with a ratchet-type or indexing drive transmission to further improve motion resolution and provide precise drug delivery.

[0049] The exemplary embodiments described herein employ an oval-shaped syringe barrel-shaped reservoir 22 to contain the medication or fluid to be delivered. The oval-shaped syringe barrel-shaped reservoir 22 provides anti-rotation features and associated advantages. For example, the inherent anti-rotation provided by the design of the oval-shaped syringe barrel-shaped reservoir 22 naturally prevents barrel rotation when torque is applied. The oval shape also has the advantage of reducing the overall height of the device. However, other components can be employed to achieve the same anti-rotation feature. For example, the innermost threads can be keyed to a detent or other feature of the stopper assembly 28 or to a drive component or surface of the plunger drive assembly 30. Thus, even if the reservoir 22 is not oval-shaped (e.g., has a circular cross-section), anti-rotation of the plunger drive assembly 30 relative to the inner wall of the reservoir 22 during axial translation is achieved.

[0050] The reservoir 22 can be configured to be durable rather than removable and can be configured to be pre-installed within the fluid delivery device housing 14. The reservoir 22 can be made of a material similar to the syringe barrel and associated stopper. The reservoir 33 can be pre-filled, with the plunger drive assembly 30 initially in a retracted position. Alternatively, the fluid delivery device housing 14 can include a fill port and a fluid pathway 26 from the fill port to the reservoir 22. The fill port can be configured for a user to fill with a syringe or for use with a filling station that fluidly couples to the fill port.

[0051] Although various persons, including but not limited to patients or medical professionals, may operate or use exemplary embodiments of the present disclosure, for the sake of brevity, an operator or user will hereinafter be referred to as a "user."

[0052] Although various fluids may be employed in exemplary embodiments of the present disclosure, for the sake of simplicity, the liquid within the injection device will hereinafter be referred to as the "fluid."

[0053] Those skilled in the art will understand that the present disclosure is not limited in its application to the details of construction and the arrangement of components set forth below or illustrated in the drawings. The embodiments herein are capable of other embodiments and of being practiced or carried out in various ways. It is also understood that the phraseology and terminology used herein are for descriptive purposes and should not be construed as limiting. The use of "including," "comprising," or "having," and variations thereof, herein means the inclusion of additional items in addition to the items listed thereafter and their equivalents. Unless otherwise limited, the terms "connected," "coupled," and "mounted," and variations thereof, herein are used broadly to encompass both direct and indirect connections, couplings, and attachments. Furthermore, the terms "connected" and "coupled," and variations thereof, are not limited to physical or mechanical connections or couplings. Furthermore, terms such as top, bottom, and upper surface are relative and are used to aid in illustration, but are not limiting.

[0054] Components of the illustrated devices, systems, and methods employed in accordance with the illustrated embodiments may be implemented at least in part in digital electronic circuitry, analog electronic circuitry, or computer hardware, firmware, software, or combinations thereof. These components may be implemented as a computer program product, such as a computer program, program code, or computer instructions tangibly embodied in an information medium or machine-readable storage device for execution by, or to control the operation of, a data processing apparatus such as a programmable processor, a computer, or multiple computers.

[0055] The above description and illustrations are intended to be examples only and are not intended to limit the invention in any way, except as set forth in the following claims. It is particularly noted that those skilled in the art can easily combine various technical aspects of the various elements of the various exemplary embodiments described above in many other ways, all of which are considered to be within the scope of the claims.

Claims

1. 1. A fluid delivery device comprising: a reservoir configured to be pre-installed and permanently installed within a housing of the fluid delivery device, the reservoir comprising an outlet 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 interior wall of the reservoir to prevent fluid delivered to a fluid chamber defined by a first side of the plunger and constituting the outlet port from leaking into a portion of the reservoir defined by a second side of the plunger; a plunger drive assembly comprising a plurality of telescopic screws attached to a proximal end of the reservoir, the telescopic screws moving from a telescopic configuration not extending into the reservoir to an extended configuration extending from the proximal end of the reservoir into the reservoir upon rotation of an outermost drive screw; the plurality of telescopic expansion screws include an innermost screw coupled to the plunger and constrained from rotation by an anti-rotation mechanism; the reservoir further comprises a gear anchor attached to a proximal end of the reservoir, the gear anchor comprising an opening dimensioned to receive a distal end of the outermost drive screw and to allow the telescopic screw to extend into the reservoir when the outermost drive screw is rotated; The fluid delivery device, wherein the gear anchor is disk-shaped and dimensioned to be press-fit into the proximal end of the reservoir.

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

3. 2. The fluid delivery device of claim 1, wherein the anti-rotation mechanism is the reservoir and the plunger having a non-circular cross section to prevent rotation of the plunger within the reservoir when the outermost drive screw is rotated.

4. The fluid delivery device of claim 3 , wherein the reservoir and the plunger each have an oval cross section.

5. 2. The fluid delivery device of claim 1, wherein the anti-rotation mechanism comprises a pusher disposed between the plunger and a distal end of the innermost screw, the pusher adjacent 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.

6. The fluid delivery device of claim 5 , wherein the pusher includes a keying feature that cooperates with a corresponding keying feature on the distal end of the innermost thread to engage the innermost thread with the pusher.

7. 7. The fluid delivery device of claim 6, wherein the keying feature of the pusher comprises a detent and the corresponding keying feature on the distal end of the innermost screw is sized and / or shaped to be press-fit into a correspondingly sized and / or shaped detent.

8. The fluid delivery device of claim 7 , wherein the detent includes a through hole distal to the pusher, the distal end of the innermost screw extending through the through hole.

9. The fluid delivery device of claim 8 , wherein the pusher comprises a protrusion on the distal side of the pusher, the through-hole extending through the protrusion.

10. The fluid delivery device of claim 5 , wherein the pusher comprises at least one through hole for ventilation.

11. The fluid delivery device of claim 5 , wherein the pusher comprises a recess along at least a portion of the periphery of the pusher for ventilation.

12. 2. The fluid delivery device of claim 1, wherein the anti-rotation mechanism comprises a detent on the second side of the plunger sized to cooperate with a 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.

13. The fluid delivery device of claim 12 , wherein the distal end of the innermost thread is sized and / or shaped to be press-fit into a correspondingly sized and / or shaped detent.

14. 2. The fluid delivery device of claim 1, wherein the plurality of telescoping screws comprises an outermost drive screw having an inner diameter and inner threads sized to receive a sleeve screw, the sleeve screw having outer threads configured to cooperate with the inner threads to advance the sleeve screw within the outermost drive screw when the outermost drive screw is rotated.

15. 15. The fluid delivery device of claim 14, wherein the sleeve screw has an inner diameter and inner threads sized to receive the innermost threads, the innermost threads having outer threads configured to cooperate with the inner threads of the sleeve screw to advance the innermost thread within the sleeve screw when the sleeve screw is rotated.

16. The fluid delivery device of claim 1 , wherein the plurality of telescopic screws have right-hand threads and internal and external thread parameters that each employ the same pitch.

17. The fluid delivery device of claim 1 , wherein the plurality of telescopic screws have left-handed threads and internal and external thread parameters that each employ the same pitch.

18. The fluid delivery device of claim 1 , wherein the gear anchor includes a through hole for ventilation.

19. 10. The fluid delivery device of claim 1, wherein the opening in the gear anchor is configured to provide stable support to the outermost drive screw while allowing the outermost drive screw to rotate relative to the gear anchor.

20. The fluid delivery device of claim 1 , wherein the distal end of the innermost screw is flush with a distal side of the gear anchor when the plunger drive assembly is in a nested configuration.

21. 2. The fluid delivery device of claim 1, wherein when the plunger drive assembly is in a nested configuration, the distal end of the innermost screw protrudes from the distal side of the gear anchor a predetermined length corresponding to a depth of a detent provided on either the second side of the plunger or an intermediate pusher between the plunger and the distal end of the innermost screw.

22. 10. The fluid delivery device of claim 1, further comprising a thrust bearing mechanism for the plunger drive assembly and a support structure for the plunger drive assembly that minimizes axial thrust loads from the expansion screw.

23. 23. The fluid delivery device of claim 22, wherein the thrust bearing mechanism comprises a cap disposed on the outermost drive screw, the cap facing the proximal end of the plunger drive assembly and having a boss that contacts a portion of the support structure to resist axial thrust loads generated by the plunger drive assembly, the plunger, or fluid in the fluid chamber.

24. The fluid delivery device of claim 1 , further comprising an encoder associated with the plunger drive assembly for generating feedback data related to operation of the plunger drive assembly.

25. The fluid delivery device of claim 1 , wherein the anti-rotation feature is disposed at the distal end of the innermost thread.

26. 1. A fluid delivery device comprising: a reservoir comprising an outlet 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 interior wall of the reservoir to prevent fluid delivered to a fluid chamber defined by a first side of the plunger and constituting the outlet port from leaking into a portion of the reservoir defined by a second side of the plunger; a plunger drive assembly comprising a plurality of telescopic screws attached to a proximal end of the reservoir, the telescopic screws moving from a telescopic configuration not extending into the reservoir to an extended configuration extending from the proximal end of the reservoir into the reservoir upon rotation of an outermost drive screw; the plurality of telescopic expansion screws include an innermost screw coupled to the plunger and constrained from rotation by an anti-rotation mechanism; the anti-rotation mechanism includes a pusher disposed between the plunger and a distal end of the innermost screw, the pusher proximally adjacent the plunger and configured to move along the longitudinal axis of the reservoir in response to rotation of the outermost screw; the pusher including a keying mechanism that cooperates with a corresponding keying mechanism on the distal end of the innermost screw to engage the innermost screw with the pusher; the keying feature of the pusher comprises a detent, the corresponding keying feature on the distal end of the innermost screw being sized and / or shaped to be press-fit into a correspondingly sized and / or shaped detent; the detent includes a through hole distal to the pusher, the distal end of the innermost screw extending through the through hole; The fluid delivery device, wherein the distal end of the innermost screw is heat staked to the distal side of the pusher at the through hole.

27. 27. The fluid delivery device of claim 26, wherein the through-hole comprises an anti-rotation groove.

28. 1. A fluid delivery device comprising: a reservoir comprising an outlet 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 interior wall of the reservoir to prevent fluid delivered to a fluid chamber defined by a first side of the plunger and constituting the outlet port from leaking into a portion of the reservoir defined by a second side of the plunger; a plunger drive assembly comprising a plurality of telescopic screws attached to a proximal end of the reservoir, the telescopic screws moving from a telescopic configuration not extending into the reservoir to an extended configuration extending from the proximal end of the reservoir into the reservoir upon rotation of an outermost drive screw; the plurality of telescopic expansion screws include an innermost screw coupled to the plunger and constrained from rotation by an anti-rotation mechanism; the plurality of telescoping screws comprises an outermost drive screw having an inner diameter and inner threads sized to receive a sleeve screw, the sleeve screw having outer threads configured to cooperate with the inner threads to advance the sleeve screw within the outermost drive screw when the outermost drive screw is rotated; the sleeve thread has an inner diameter and internal threads sized to receive the innermost threads, the innermost threads having external threads configured to cooperate with the internal threads of the sleeve thread to advance the innermost thread within the sleeve thread when the sleeve thread is rotated; A fluid delivery device, wherein the torque ratio of the innermost screw is less than the torque ratio of the sleeve screw, and the torque ratio of the sleeve screw is less than the torque ratio of the outermost drive screw to allow the innermost screw, constrained from rotation, to extend along the sleeve screw into the reservoir before the sleeve screw begins to rotate relative to the outermost drive screw and advances into the reservoir.

29. 1. A fluid delivery device comprising: a reservoir comprising 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 against an interior wall of the reservoir to prevent fluid delivered to a fluid chamber defined on a first side of the plunger and constituting the outlet port from leaking into a portion of the reservoir defined by a second side of the plunger; a plunger drive assembly comprising a plurality of telescopic screws attached to a proximal end of the reservoir, the telescopic screws moving from a telescopic configuration not extending into the reservoir to an extended configuration extending from the proximal end of the reservoir into the reservoir upon rotation of an outermost drive screw; the plurality of telescopic expansion screws include an innermost screw coupled to the plunger and constrained from rotation by an anti-rotation mechanism; the anti-rotation mechanism includes a pusher disposed between the plunger and a distal end of the innermost screw, the pusher proximally adjacent the plunger and configured to move along the longitudinal axis of the reservoir in response to rotation of the outermost screw; A fluid delivery device wherein the pusher includes a keying feature that cooperates with a corresponding keying feature on the distal end of the innermost screw to engage the innermost screw with the pusher.

30. 30. The fluid delivery device of claim 29, wherein the reservoir is a syringe barrel-type container.

31. the anti-rotation mechanism being the reservoir and the plunger having a non-circular cross section to prevent rotation of the plunger within the reservoir when the outermost drive screw is rotated; and / or 30. The fluid delivery device of claim 29, wherein the reservoir and the plunger each have an oval cross-section.

32. 30. The fluid delivery device of claim 29, wherein the anti-rotation mechanism comprises a pusher disposed between the plunger and a distal end of the innermost screw, the pusher adjacent 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.

33. the pusher has at least one through hole for ventilation; and / or 33. The fluid delivery device of claim 32, wherein the pusher comprises a recess along at least a portion of the periphery of the pusher for ventilation.

34. the keying feature of the pusher comprises a detent, the corresponding keying feature on the distal end of the innermost screw being sized and / or shaped to be press-fit into a correspondingly sized and / or shaped detent; and / or 30. The fluid delivery device of claim 29, wherein the detent comprises a through hole distal to the pusher, the distal end of the innermost screw extending through the through hole.

35. the distal end of the innermost screw is heat staked to the distal side of the pusher at the through hole; and / or 35. The fluid delivery device of claim 34, wherein the through-hole comprises an anti-rotation groove.

36. 35. The fluid delivery device of claim 34, wherein the pusher comprises a protrusion on the distal side of the pusher, the through-hole extending through the protrusion.

37. the anti-rotation mechanism comprises a detent on the second side of the plunger sized to cooperate with a 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. and / or 30. The fluid delivery device of claim 29, wherein the distal end of the innermost thread is sized and / or shaped to be press-fit into a correspondingly sized and / or shaped detent.

38. the plurality of telescoping screws includes an outermost drive screw having an inner diameter and inner threads sized to receive a sleeve screw, the sleeve screw having outer threads configured to cooperate with the inner threads to advance the sleeve screw within the outermost drive screw when the outermost drive screw is rotated; and / or the sleeve thread has an inner diameter and internal threads sized to receive the innermost threads, the innermost threads having external threads configured to cooperate with the internal threads of the sleeve thread to advance the innermost thread within the sleeve thread when the sleeve thread is rotated; and / or 30. The fluid delivery device of claim 29, wherein the torque ratio of the innermost screw is less than the torque ratio of the sleeve screw, and the torque ratio of the sleeve screw is less than the torque ratio of the outermost drive screw to allow the innermost screw, constrained from rotation, to extend along the sleeve screw into the reservoir before the sleeve screw begins to rotate relative to the outermost drive screw and advances into the reservoir.

39. The plurality of telescopic screws have right-hand threads and internal and external thread parameters that respectively adopt the same pitch; Or, 30. The fluid delivery device of claim 29, wherein the plurality of telescopic expansion screws have left-handed threads and internal and external thread parameters that each employ the same pitch.

40. the reservoir further comprising a gear anchor attached to a proximal end of the reservoir, the gear anchor comprising an opening dimensioned to receive a distal end of the outermost drive screw and to allow the telescopic screw to extend into the reservoir when the outermost drive screw is rotated. and / or 30. The fluid delivery device of claim 29, wherein the opening in the gear anchor is configured to provide stable support to the outermost drive screw while allowing the outermost drive screw to rotate relative to the gear anchor.

41. 41. The fluid delivery device of claim 40, wherein the gear anchor is disk-shaped and dimensioned to be press-fit into the proximal end of the reservoir.

42. 41. The fluid delivery device of claim 40, wherein the gear anchor comprises a through hole for ventilation.

43. 41. The fluid delivery device of claim 40, wherein the distal end of the innermost screw is flush with a distal side of the gear anchor when the plunger drive assembly is in a nested configuration.

44. 41. The fluid delivery device of claim 40, wherein when the plunger drive assembly is in a nested configuration, the distal end of the innermost screw protrudes from the distal side of the gear anchor a predetermined length corresponding to a depth of a detent provided on either the second side of the plunger or an intermediate pusher between the plunger and the distal end of the innermost screw.

45. The plunger drive assembly further includes a thrust bearing mechanism provided for the plunger drive assembly, and a support structure for the plunger drive assembly that minimizes axial thrust load from the expansion screw. and / or 30. The fluid delivery device of claim 29, wherein the thrust bearing mechanism comprises a cap disposed on the outermost drive screw, the cap facing the proximal end of the plunger drive assembly and having a boss that contacts a portion of the support structure to resist axial thrust loads caused by the plunger drive assembly, the plunger, or fluid in the fluid chamber.

46. 30. The fluid delivery device of claim 29, further comprising an encoder provided to the plunger drive assembly for generating feedback data related to operation of the plunger drive assembly.

Images