Drug Delivery Devices

Abstract

A drug delivery device comprising a base plate that engages with a cover to form an interior, the interior including a pump drive mechanism for driving a drug through the device, a drive train engaged with the pump drive mechanism, a magnetic encoder including an encoder hub mechanically coupled to the drive train, the encoder hub including a magnet, and a sensor that measures a magnetic field from the magnet to determine a rotational position of the drive train.

Description

[Technical field]

[0001] cross reference This application claims priority under 35 U.S.C. 119(e) to U.S. Provisional Application No. 63 / 318,258, filed March 9, 2022, which is incorporated by reference herein in its entirety.

[0002] Field The present disclosure relates to medical devices, and more particularly to drug delivery devices with infusion pump systems capable of detecting the amount of drug dispensed. [Background technology]

[0003] Infusion pumps typically have a reservoir with a known amount of drug and a known dispense stroke volume to count down the dose and estimate how much drug is expelled from the reservoir, out of the infusion pump, and into the patient. Alternative forms of coding for determining the amount of drug expelled include mechanical switches and spring-loaded electrical connections.

[0004] For example, two conductive spring elements and a conductive material coupled to the drive gear can be used to sense angular rotation. The conductive material coupled to the drive gear is spaced so that the first spring contacts either an insulator or the conductive material based on the rotational position of the drive gear. The second spring is always in contact with the conductive material. Thus, as the drive gear rotates, the conductive spring intermittently completes or shorts a circuit. The number of increments between shorts confirms the rotation of the drive gear and, ultimately, the amount of drug dispensed.

[0005] For medical devices such as wearable drug delivery pumps, patch pumps, or infusion pumps, other means of measuring how much drug is being expelled are desirable. In general, there is a need for accurate detection of drug delivery that improves accuracy, product life, energy efficiency, and manufacturability while reducing part count and cost. Summary of the Invention [Means for solving the problem]

[0006] The exemplary embodiments disclosed herein may provide solutions to at least the problems and / or shortcomings set forth above, as well as others not set forth above, and the exemplary embodiments do not necessarily, and may not, overcome all, if any, of the shortcomings set forth above.

[0007] The matters exemplified in this description are provided to assist in a comprehensive understanding of the exemplary embodiments of the present disclosure. Therefore, those skilled in the art will recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present disclosure. In addition, descriptions of well-known functions and structures are omitted for clarity and conciseness.

[0008] An exemplary aspect of the present disclosure provides a low resolution magnetic encoder in a drug delivery device in which an array of magnets are fixed to an encoder hub and mechanically coupled to a drive gear that can be aligned with a magnetic Hall effect sensor to provide rotational feedback indicative of the detected magnetic field.

[0009] Another exemplary aspect of the present disclosure provides a low resolution magnetic encoder including a single multi-pole magnet within the drug delivery device that can be mechanically coupled to a drive gear, whereby the drive gear can be aligned with a magnetic Hall effect sensor to provide rotational feedback indicative of the detected magnetic field.

[0010] An exemplary implementation of the disclosed aspects may be used to measure the rotational position of a drive gear of a drive train to facilitate detection of the amount of drug dispensed from a drug delivery device.

[0011] According to an example implementation, the magnetic Hall effect sensor may be configured to not increase friction acting on the drive gear. As a result, according to an example implementation, the drivetrain may be more power efficient due to fewer external physical influences.

[0012] According to a further exemplary implementation, the resolution of a magnetic encoder may be altered by increasing or decreasing the number of magnetic poles seen by a magnetic Hall effect sensor within a given angular rotation. For example, a magnetic encoder may be optimized by maximizing the number of magnetic poles while avoiding magnetic interference between the poles or crosstalk between magnets.

[0013] According to an exemplary implementation, a single multi-pole magnet can be configured to provide a low parts count solution, increasing manufacturability and reducing cost of the magnetic encoder solution through simpler manufacturing processes.

[0014] Additionally, in further exemplary implementations, optical sensors may be provided in conjunction with magnetic encoders to facilitate, for example, finer motor control and greater drug delivery accuracy.

[0015] An exemplary embodiment of the present disclosure provides a drug delivery device including a base plate that engages with a cover to form an interior including a pump drive mechanism for driving a drug through the device, a drive train engaged to the pump drive mechanism, an encoder hub mechanically coupled to the drive train, the encoder hub including a magnet, and a sensor that measures a magnetic field from the magnet to determine a rotational position of the drive train.

[0016] According to further exemplary aspects of the present disclosure, the drug delivery device may include one of a patch pump, an infusion pump, and an automated insulin delivery device.

[0017] According to a further exemplary aspect of the present disclosure, the pump drive mechanism may include a plunger driven by a lead screw.

[0018] According to a further exemplary aspect of the present disclosure, the drive train may include a drive gear, the output of the drive train engages with a drive nut, and the drive nut is a rotating component that engages with the lead screw.

[0019] According to a further exemplary aspect of the present disclosure, the drive gear may be aligned with the sensor.

[0020] According to a further exemplary aspect of the present disclosure, an encoder hub may be coupled to the drive gear to measure rotational position.

[0021] According to further exemplary aspects of the present disclosure, the magnet may be configured or implemented as, for example, a plurality of equally spaced magnets.

[0022] According to a further exemplary aspect of the present disclosure, a configuration may be provided in which the polarity of the magnets facing away from the central axis of the drive gear remains constant.

[0023] According to a further exemplary aspect of the present disclosure, a configuration may be provided in which the polarities of the magnets facing away from the central axis of the drive gear alternate in series with respect to the drive gear.

[0024] According to a further exemplary aspect of the present disclosure, a configuration may be provided in which the magnets may be axially polarized.

[0025] According to a further exemplary aspect of the present disclosure, a configuration may be provided in which the magnets may be radially polarized.

[0026] According to further exemplary aspects of the present disclosure, the magnet may be configured as a single multi-pole magnet having multiple magnet arms spaced about the encoder hub.

[0027] According to a further exemplary aspect of the present disclosure, a configuration may be provided in which the sensor may be mounted on a top surface of the circuit board.

[0028] According to a further exemplary aspect of the present disclosure, a configuration may be provided in which the sensor may be attached to a bottom surface of the circuit board.

[0029] According to a further exemplary aspect of the present disclosure, a configuration may be provided in which the sensor may be aligned perpendicular to the axis of rotation of the drive gear.

[0030] According to a further exemplary aspect of the present disclosure, the sensor may include one of a magnetic Hall effect sensor and a magnetoresistive sensor.

[0031] According to further exemplary aspects of the present disclosure, the drug delivery device may include an optical sensor disposed, for example, in an intermediate portion of the drive train.

[0032] According to further exemplary aspects of the present disclosure, the optical sensor may include an emitter that emits light, for example, from an LED or laser light, and a receiver that detects the light or laser light.

[0033] According to further exemplary aspects of the present disclosure, the optical sensor may be configured to include an optical fan blade configured to split the light, laser light, or beam, and the optical sensor may be configured to detect when the light, laser light, or beam is split.

[0034] According to further exemplary aspects of the present disclosure, a magnetic encoder may be configured to include a ring magnet having one or more magnetized sections.

[0035] Additional and / or other aspects and advantages of the disclosure will be set forth in the description that follows, will be obvious from the description, or may be learned by practice of the disclosure. [Brief description of the drawings]

[0036] The above and / or other exemplary aspects and advantages of the present disclosure will become apparent and will be more readily understood from the following description of exemplary embodiments taken in conjunction with the accompanying drawings. [Figure 1] FIG. 1 is a perspective view of a wearable drug delivery device configured in accordance with an exemplary embodiment of the present disclosure. [Diagram 2] 2 is a top perspective view of the drug delivery device of FIG. 1 with the cover removed and configured in accordance with an exemplary embodiment of the present disclosure. FIG. [Diagram 3] FIG. 2 is a block diagram of exemplary components of the drug delivery device of FIG. 1 configured in accordance with an exemplary embodiment of the present disclosure. [Figure 4] FIG. 3 is a side view of a drive train of the drug delivery device of FIG. 2 configured in accordance with an exemplary embodiment of the present disclosure. [Diagram 5] FIG. 5 is a perspective view of a motor and planetary gearbox of the drug delivery device of FIG. 4 configured in accordance with an exemplary embodiment of the present disclosure. [Figure 6] FIG. 3 is a side view of a magnetic pole in a magnetic encoder of the drug delivery device of FIG. 2 configured in accordance with an exemplary embodiment of the present disclosure. [Figure 7] 7 is a legend and graph identifying magnetic Hall effect sensor output based on magnetic poles in a magnetic encoder of the drug delivery device of FIG. 6 configured in accordance with an exemplary embodiment of the present disclosure; [Figure 8] 7 is a graph showing sensor measurements of a magnetic encoder having eight poles in the drug delivery device of FIG. 6 configured in accordance with an exemplary embodiment of the present disclosure. [Figure 9] FIG. 7 is a side view of a magnetic pole in a magnetic encoder of the drug delivery device of FIG. 6 configured in accordance with an exemplary embodiment of the present disclosure. [Figure 10] FIG. 13 is a perspective view of a ring magnet in a magnetic encoder disposed in a drug delivery device configured according to a second exemplary embodiment of the present disclosure. [Figure 11] FIG. 13 is a cross-sectional view of a multi-pole magnetic encoder disposed on a drug delivery device configured according to a third exemplary embodiment of the present disclosure. [Figure 12]12 is a graph showing sensor measurements of a magnetic encoder having 20 poles in the drug delivery device of FIG. 11 configured in accordance with an exemplary embodiment of the present disclosure. [Figure 13] 13 is a graph showing sensor measurements of a multi-pole magnetic encoder having 20 poles including missed interrupts in drug delivery constructed in accordance with a fourth exemplary embodiment of the present disclosure.

[0037] Throughout the drawings, like reference numbers will be understood to refer to like elements, features, and structures. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0038] Referring now to the drawings, in which like reference numerals refer to the same or corresponding parts throughout the several views, embodiments of the present disclosure are described as follows.

[0039] It will be understood that the terms "include," "including," "comprise," and / or "comprising," as used herein, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of another other feature, integer, step, operation, element, component, and / or group thereof.

[0040] It will be further understood that, although terms such as "first," "second," "third," and the like may be used herein to describe various elements, components, regions, layers, and / or sections, these elements, components, regions, layers, and / or sections may not be limited by these terms. These terms are used only to distinguish one element, component, region, layer, or section from another element, component, region, layer, or section.

[0041] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. A phrase such as "at least one of," when following a list of elements, modifies the entire list of elements and does not modify the individual elements of the list. Furthermore, terms such as "unit," "-er (-or)," and "module" described herein refer to an element for performing at least one function or operation and may be implemented in hardware.

[0042] Various terms are used to refer to particular system components. Different companies may use different names for the components, and this specification does not intend to distinguish between components that differ in name but not function.

[0043] Issues of these exemplary embodiments that are apparent to one of ordinary skill in the art to which these exemplary embodiments pertain may not be described in detail herein. Furthermore, various features of the exemplary embodiments may be implemented individually or in any combination or combinations as would be understood by one of ordinary skill in the art of drug delivery devices.

[0044] As described below, an exemplary embodiment of a low-resolution magnetic encoder in a drug delivery device is useful for accurately measuring dispensed medication. Drug delivery devices include, for example, patch pumps, infusion pumps, or automated insulin delivery devices. Infusion pump systems are generally understood to be a type of pump that works on the principle of filling a chamber (e.g., with liquid drug from a reservoir) in one step and then expelling the drug from the chamber (e.g., into a delivery device such as a cannula deployed in the patient) in another step.

[0045] In further exemplary embodiments of the present disclosure, the low resolution magnetic encoder described below employs several technology principles such as: (a) a magnetic Hall effect sensor; (b) a series of magnets providing configurable magnetic poles; (c) an optical sensor providing fine motor control and high drug delivery accuracy; and (d) a multi-pole magnetic encoder or ring magnet design.

[0046] 1 is a perspective view of a wearable drug delivery device 10 including a base plate 12, a cover 14, and an insertion mechanism 16. The insertion mechanism 16 is configured to insert a cannula into a patient's skin to deliver a drug.

[0047] Figure 2 is a perspective view of the drug delivery device 10 of Figure 1 with the cover 14 removed. The base plate 12 supports the insertion mechanism 16, a motor 28, a power source such as a battery 30, a printed circuit board (PCB) 32, memory 33, and other electronic components, as well as a reservoir 26 for storing a drug to be delivered to a patient (or user) via an outlet fluid pathway from an outlet port of the reservoir 26 through the insertion mechanism 16. In an exemplary embodiment, the reservoir 26 has an inlet port connected to a fill port via an inlet fluid pathway for receiving the drug.

[0048] FIG. 3 is a system diagram 100 illustrating an exemplary implementation of components in an exemplary drug delivery device 10 having the infusion pump system of FIGS. 1-3 for detecting delivered drug. Referring to the example of FIG. 3, the drug delivery device 10 may include a power storage subsystem 102, a fluidics subsystem 104, and an electronics subsystem 106 for controlling the operation of components in the fluidics subsystem 104, such as an insertion mechanism 16 for deploying a cannula for insertion into an infusion site on the patient's skin. The power storage subsystem 102 includes a power source, such as one or more batteries 30, for powering the components in the electronics subsystem and the fluidics subsystems 104 and 106. The fluidics subsystem 104 includes a motor 28, a drive train 42, a pump drive mechanism 37, and a drug-filled reservoir 26. The pump drive mechanism 37 includes a plunger 36 driven by a lead screw 34. Additionally, the electronics subsystem 106 includes a memory device 33 that cooperates with a magnetic Hall effect sensor 50 to measure the dispensed drug.

[0049] FIG. 4 illustrates the drive train 42 in cooperation with the magnetic encoder 60. Although the drive train 42 is illustrated as a compound gear, one skilled in the art will readily appreciate that other components may be implemented to translate the input rotation of the motor 28 to the drive gear 40 and the drive nut (or lead screw nut) 41. For example, a current may be applied to rotate the motor 28, which is translated throughout the drive train 42 to the drive gear 40. The drive nut 41 is advantageously rotated by the drive gear 40. In an exemplary embodiment, the drive nut 41 is a rotating component that may engage or be rotationally coupled with the lead screw 34. Rotation of the lead screw 34 causes linear motion of the plunger 36 and eventual expulsion of the drug from the drug delivery device 10. In other words, in an exemplary embodiment, the drive nut 41 is the rotating component that is mechanically closest to the plunger 36, whereby detection of rotational motion or lack thereof of the drive nut 41 provides a proximate indication of the axial displacement or lack thereof of the plunger 36. 4, drive gear 40 is rotationally fixed to drive nut 41 and engages drive train 42 operated by motor 28. Drive gear 40 is further constrained by lead screw 34 and the main frame of the assembly to react to forces from plunger movement and forces from fluid pressure.

[0050] In another embodiment, the motor 28 includes an output shaft 29 that is aligned with and drives the pump drive mechanism 37 directly, without the use of a drive train 42 in a manner similar to that described above. An exemplary motor 28 includes a stepper motor. If the morphology is different (e.g., narrow reservoir 26), a stepper motor may be used. In other words, unless a small pitch of the lead screw 34 is implemented (which is difficult to achieve) or the cross section of the reservoir 26 is reduced, resolution is likely to be significantly reduced. A smaller cross section of the reservoir 26 is much easier to achieve, especially when delivering small amounts of drug.

[0051] In this embodiment, the resolution of the magnetic encoder 60 may be measured anywhere in the drivetrain 42 based on the desired tradeoff between the accuracy of the sensor 50 and the required resolution. For example, if the sensor 50 in the drivetrain is moved closer to the motor, the resolution may be improved. However, to achieve improved resolution, a more accurate sensor 50 would be required. The sensor 50 may be located at the output of the drivetrain 42 where a low resolution encoder is measured. Alternatively, the sensor 50 may be located at the input end of the drivetrain 42 where a high resolution encoder is measured.

[0052] In yet other embodiments, the drive train 42 may include a belt system, friction gears, or other forms of power transmission (as opposed to conventional gears). Friction gears may be advantageous where conventional gears have backlash-type problems.

[0053] 4 further illustrates a printed circuit board 32 having a top surface 38 and a bottom surface 39 with a sensor 50 disposed on one of the two surfaces. The sensor 50 includes a low resolution magnetic proximity sensor, such as a magnetic Hall effect sensor or a magnetoresistive sensor. Various magnetic Hall effect sensors 50 may be used to accommodate different magnetic field strengths and / or sensitivities.

[0054] In an exemplary embodiment, the sensor 50 can be located anywhere within the drug delivery device 10, i.e., between the cover 14 and the base plate 12. In another embodiment, the sensor 50 can be connected by a wired or flexible circuit instead of through the circuit board 32.

[0055] In an exemplary embodiment, the sensor 50 is aligned perpendicular to the axis of rotation of the drive gear 40 to measure the magnetic field of the magnet 64, thereby ascertaining any rotation of the drive gear 40 for a given rotational input from the motor 28, which rotation may result in a corresponding movement of the plunger 26. The output of the sensor 50 may thus be used to provide real-time feedback of the drug being dispensed to the smartphone 52, for example, via a Bluetooth device. In another exemplary embodiment, the output of the sensor 50 may facilitate precise control of the dispensing operation of the drug delivery device 10. According to an exemplary configuration, the sensor 50 may be positioned at a predetermined distance from the magnet 64 to increase or decrease the sensitivity of the magnetic field measurement. In a preferred embodiment, the sensor 50 is attached to the pump drive mechanism 37. Further operation of the sensor 50 is described below.

[0056] 4-7 illustrate an exemplary configuration of a magnetic encoder 60 in cooperation with the drive train 42 and the sensor 50. The magnetic encoder 60 includes an encoder hub 62, for example, configured on or integrated with the drive gear 40, and a magnet member 64, for example, including a plurality of magnets 64a, 64b, 64c, 64d, 64e, 64f, 64g, 64h, configured on or integrated with the hub 62 to create a magnetic field. In operation, the magnet member 64 rotates with the drive gear 40 and as the magnet passes the Hall effect sensor 50, an interrupt is triggered that is measured by the sensor 50. The interrupt assists in determining the rotational position of the drive gear 40 and the drive train 42, as measured by the Hall effect sensor 50, and facilitates monitoring the precise operation of the drive gear 40 and the drive train 42.

[0057] In an exemplary embodiment, the encoder hub 62 is mechanically coupled to the drive gear 40, which rotationally advances the lead screw 34. The output of the Hall effect sensor 50, based on the rotation of the encoder hub 62, may thus facilitate measuring or monitoring the rotational position of the drive gear 40, whereby implementation of the magnetic encoder 60 may ensure continuity of the drive train 42. For example, if the number of interrupts measured by the sensor 50 does not match an expected amount, e.g., a particular period of time, the magnetic encoder 60 may trigger an alarm. The alarm may inform a user that the motor 28 and the magnetic encoder 60, and thus the drive gear 40, are sufficiently decoupled, e.g., due to a lack of continuity in the drive train 42. In an exemplary embodiment, such feedback of the encoder 60 may be used to determine under- and / or over-rotation of the drive gear 40, e.g., as an indication of under- and over-dosing of medication to the patient due to corresponding axial movement of the plunger 36.

[0058] In an exemplary embodiment, the magnetic material of the magnet member 64 can be varied to provide different magnetic field strengths (e.g., N52 or N42). Exemplary base materials for magnets that may be used include neodymium and iron oxide, although other magnet materials are contemplated as would be understood by one of ordinary skill in the art. In an exemplary embodiment, the magnet member 64 includes one or more magnets 64a, 64b, 64c, 64d, 64e, 64f, 64g, 64h, etc. disposed on an encoder hub 62 coupled to the drive gear 40. When two or more magnets 64a, 64b, 64c, 64d, 64e, 64f, 64g, 64h, etc. are configured equally spaced from one another and at the same distance from the central axis of the drive gear 40, an expected number of interrupts can be observed by the Hall effect sensor 50 over one complete revolution of the drive gear 40, which is based on the input rotation of the motor 28 via the drive train 42.

[0059] In another exemplary implementation of the disclosed embodiments, as shown, for example, in FIG. 11, the magnetic encoder 60 includes a single multi-pole magnet 90 having multiple equally spaced magnet arms 92. In an exemplary implementation of the disclosed embodiments, the single multi-pole magnet 90 may replace the magnet 64 and the encoder hub 62 of the magnetic encoder 60. For example, the multi-pole magnet 90 may be molded as one component and then magnetized during a separate processing step. Both of these configurations are described below.

[0060] The magnets 64a, 64b, 64c, 64d, 64e, 64f, 64g, 64h, etc. may be arranged with various polarities. In an exemplary implementation of the disclosed embodiment, the polarity of the magnets 64a, 64b, 64c, 64d, 64e, 64f, 64g, 64h, etc. facing away from the central axis of the drive gear 40 remains constant. In another exemplary embodiment, the polarity of the magnets 64a, 64b, 64c, 64d, 64e, 64f, 64g, 64h, etc. facing away from the central axis of the drive gear 40 alternates in series with respect to the drive gear 40. In yet another exemplary embodiment, the polarity of the magnets facing away from the central axis of the drive gear 40 does not alternate in series with respect to the central axis of the drive gear 40. For example, the polarities are randomly arranged with respect to the central axis of the drive gear 40. Additionally, the plurality of magnets 64a, 64b, 64c, 64d, 64e, 64f, 64g, 64h, etc. may be radially polarized as shown in Figures 2, 9, and 10. According to yet another exemplary embodiment, the plurality of magnets 64a, 64b, 64c, 64d, 64e, 64f, 64g, 64h, etc. may be configured to be axially polarized. For example, the magnetic poles of each of the pair of magnets 64 may include, for example, one of NNNN, NSNS, SNNN, or NNSS. The above configurations are exemplary and one of skill in the art will appreciate, for example, other pole orientations, numbers of magnets used, polarity patterns, and various hub materials within the scope of the present disclosure.

[0061] 4 further illustrates an exemplary embodiment including an optical sensor 44 and optical fan blades 46. The optical sensor 44 may be configured to include, for example, a laser beam emitter and receiver, with the optical fan blades 46 disposed between the emitter and receiver. The optical sensor 44 identifies an interruption, for example, when the receiver determines that one of the optical fan blades 46 rotates to block or split the emitted laser beam, such that the optical sensor 44 receives binary feedback based on whether the laser beam is split.

[0062] In another embodiment, the optical sensor 44 includes light emitted from a light emitting diode (LED). The optical fan blade 46 operates with light similar to a laser beam, as described above.

[0063] In an exemplary embodiment, the optical fan blades may include three optical fan blades 46 spanning 60°, whereby the gap between each of the optical fan blades 46 is also 60°. Such a configuration provides six transition points of the laser beam for every 360° rotation of the optical fan blades 46. The transition points are defined as when the laser beam transitions from contacting the optical fan blade 46 to being received by the receiver, and when the laser beam transitions from being received by the receiver to contacting the optical fan blade 46 (and vice versa). In various exemplary embodiments, more blades may be provided in conjunction with the optical sensor 44. In certain exemplary configurations, various dimensions, numbers, and positioning of the fan blades may increase or decrease the error rate of detection by the optical sensor 44.

[0064] 5, an exemplary configuration provides a motor 28 that includes a planetary gearbox 43 at the output of the motor 28 with an optical fan blade 46 of an optical sensor 44 coupled to the output of the planetary gearbox 43. As shown in FIGS. 4 and 5, the drivetrain 42 includes or is mechanically coupled to gears within the planetary gearbox 43. Thus, the optical sensor 44 is essentially located in the center of the drivetrain 42 and may provide unique advantages while balancing various design objectives, as described below, for example, gear reduction or gear amplification may occur upstream and downstream of the optical sensor 44.

[0065] In an exemplary embodiment, the accuracy of detecting and monitoring the rotation of the drive gear 40 may be maximized, despite the need for very small angular rotations. For example, locating the optical sensor 44 closer to the output shaft 29 of the motor 28 allows for a gear reduction from the drive train 42 to amplify and increase the resolution to provide a more accurate measurement of very small angular rotations (allowing for finer control of the input rotation). By way of another example, locating the optical sensor 44 on the drive gear 40 may provide coarser control or smaller angular rotations (e.g., 1.28°) at the drive gear 40.

[0066] According to a further exemplary embodiment, the optical sensor 44 may minimize the possibility of gear windup or backlash when placing the optical sensor 44 close to the output of the drivetrain 42. In this way, gear tooth errors and error amplification due to elastic or plastic deformation of the drivetrain 42 may be minimized. For example, if the optical sensor 44 were to engage the rear of the motor 28, rotational errors may accumulate throughout the complete drivetrain 42 before any gear reduction. Tolerance clearances of the gears of the drivetrain 42 (gear backlash) may also slightly reduce the output rotations for a given input rotation of the motor 28, as well as the mechanical fits of the components (windup due to elastic or plastic deformation).

[0067] In an exemplary implementation, the optical sensor 44 can measure the angular rotation of the motor 28 to accurately determine the linear output of the plunger 36 and therefore the delivery of the drug from the drug delivery device 10. For example, as described above, when the optical sensor 44 detects a transition in the rotation of the optical fan blades 46, the current can be disconnected and the motor 28 can stop operating to indicate that the dose administration is complete. The motor 28 can then resume operation when the next dose is ready to be administered, after which the motor 28 can be stopped again when a transition is detected indicating that the dose administration is complete. This process can be repeated until all doses are administered. As explained in the examples above, the drug delivery device 10 according to the exemplary embodiment can be configured to provide a variable dose rate with either a consistent amount of time between doses or a variable amount of time between doses.

[0068] As explained in the above examples, the location of the optical sensor 44 and the optical fan blades 46 may be optimally selected with respect to the drive train 42, the drive gear 40, the motor 28, and / or the gearbox 43. In an exemplary embodiment in which the optical sensor 44 is essentially located in the center of the drive train 42, both the resolution and the error are divided and a compromise may be achieved to meet various design objectives. Such an exemplary configuration may be more cost and weight efficient since the optical sensor 44 may be relatively inexpensive and may not require an increase in size and / or weight of the drug delivery device 10. Thus, the use of the optical sensor 44 as disclosed herein may provide advantageous size and weight savings to the drug delivery device 10.

[0069] According to an exemplary embodiment, a sensor 50 may be implemented and cooperated with a magnetic encoder 60, as shown in the examples of Figures 6 and 7. In an exemplary implementation, the sensor 50 may be positioned on the outer edge of one of the teeth of the drive gear 40, perpendicularly from the center of the drive gear 40 and the magnetic encoder 60. When one tooth to the next tooth of the drive gear 40 moves relative to the sensor 50, an edge transition is detected 70. This may indicate movement of the drive nut 41 and helps to identify the pitch of the drive gear 40, which may be used to calculate the movement of the drive nut 41.

[0070] 6, each of the plurality of magnets 64a, 64b, 64c, 64d, 64e, 64f, 64g, 64h, etc. generates a magnetic field that is identified as a red oval (2X) or a blue oval (1X) depending on the polarity of the plurality of magnets 64a, 64b, 64c, 64d, 64e, 64f, 64g, or 64h, etc. When the sensor 50 detects an edge transition 70 while the drive gear 40 is rotating during operation of the drug delivery device, the sensor 50 detects an area 72 where a magnetic field is present and detects an area 74 where a magnetic field is not present.

[0071] 7 and 8 provide an illustrative example of this relationship in a chart showing the sensor output based on the angular rotation position of the magnetic encoder 60. When a magnetic field is sensed by the Hall effect sensor 50, the sensor records a zero. On the other hand, when a magnetic field is not sensed by the Hall effect sensor, the sensor records a one. As can be seen in FIGS. 7 and 8, when the sensor 50 measures the magnetic field at the outer surface of the drive gear 40, the magnetic field is detected (the sensor records a zero) the majority of the time.

[0072] For example, the magnetic Hall effect sensor 50 may verify the rotation of the drive gear 40 without increasing friction acting on the drive gear 40 and may improve the accuracy of operation since no additional physical contact is provided. Thus, the use of the magnetic Hall effect sensor 50 may provide less physical shock, greater accuracy, and more power-efficient gear operation, resulting in improved battery life. Additionally, the magnetic Hall effect sensor 50 may implement wireless communication to facilitate seamless wireless communication between the drug delivery device 10 and external devices, such as, for example, a smartphone 52, in cooperation with a Bluetooth device.

[0073] In another embodiment, the sensor 50 includes an analog sensor instead of a digital sensor. In this way, the sensor 50 may measure magnetic field strength rather than simply a 0 or 1.

[0074] As shown in Figure 9, the multiple magnets 64a, 64b, 64c, 64d, 64e, 64f, 64g, 64h, etc. may be spaced sufficiently apart, approximately 45° apart, to avoid overlap of magnetic fields at the exterior surface of the drive gear 40 where edge transitions 70 may be detected by the sensor 50. As a result, there may be a clearer distinction between when a magnetic field is detected 72 and when a magnetic field is not detected 74, as shown in the examples of Figures 7 and 8. On the other hand, if the multiple magnets 64 are more closely spaced such that the magnetic fields overlap at the exterior surface of the drive gear 40 where edge transitions 70 may be detected by the sensor 50, the magnetic fields may be discerned irregularly such that interruptions can be missed by the magnetic Hall effect sensor 50 and a reduced number of switches are observed.

[0075] According to an exemplary implementation of the disclosed embodiments, the resolution of the magnetic encoder 60 can be varied and optimized using the magnetic Hall effect sensor 50, for example, by increasing or decreasing the number of magnetic poles from one or more magnets 64a, 64b, 64c, 64d, 64e, 64f, 64g, 64h, etc. observed in a given angular rotation, so long as magnetic field interference or crosstalk between magnets is not an issue.

[0076] The example of FIG. 10 illustrates an alternative exemplary embodiment of the present disclosure in which the magnetic encoder 60 includes a magnet ring 80. For example, the magnet ring 80 may include multiple blank sections 82 and multiple magnetized sections. The multiple magnetized sections may include multiple magnetic fields that alternate between north polarity 84 and south polarity 86. The blank sections 82 may be disposed between each magnet, and each magnet may alternate polarity in a circular direction. The blank sections 82 may not be magnetized and may space the magnets to control overlap of magnetic fields from adjacent magnets. The multiple magnets in the magnet ring 80 may be polarized axially or radially.

[0077] The blank sections 82 may further include a plurality of protrusions 88 and a plurality of semicircular cavities 89. Each blank section 82 may include alternating protrusions 88 or semicircular cavities 89 in a circular direction. The plurality of protrusions 88 and the plurality of semicircular cavities 89 may be disposed on the top surface of the magnet ring 80.

[0078] In another embodiment, the magnet ring 80 may not include the blank section 82, but may include two magnetized sections. In this configuration, when the two magnetized sections have opposite polarities, the bipolar detector may sense rotation and function in a similar manner as described above.

[0079] The example of FIG. 11 illustrates an exemplary embodiment of the present disclosure providing a multi-pole magnet assembly 90 in which a single magnet replaces the magnet member 64 and / or encoder hub 62 of the exemplary embodiment above. According to an exemplary embodiment, the single multi-pole magnet assembly 90 may include multiple magnet arms 92 that are axially arranged and evenly spaced in a circular direction. For example, to simulate the presence of multiple individual magnets, a single piece of magnetic material may be molded into a desired shape and sliced ​​and polarized around the multi-pole magnet assembly 90. In an exemplary implementation, the multi-pole magnet assembly 90 may include a central magnet and eight magnet arms 92.

[0080] The example of Figure 12 provides an exemplary chart showing sensor output based on angular rotation position for a multi-pole magnet assembly 90 having 20 poles. Comparing Figures 8 and 12, in accordance with an exemplary embodiment of the present disclosure, a configuration including more magnetic poles may facilitate better resolution, provided there is no magnetic field interference (overlap) or crosstalk between the magnets.

[0081] According to an exemplary embodiment, the single piece of magnet of the multi-pole magnet assembly 90 may provide low part count, enhanced manufacturability, reduced cost, and a simpler manufacturing process. Furthermore, being a single piece of magnetic material, the multi-pole magnet assembly 90 may be configured with more magnetic poles for a given size. In an exemplary embodiment, similar to the magnetic encoder 60, the multi-pole magnet assembly 90 may be configured without extra software control to operate via a lower power, continuous power supply circuit, resulting in power savings and possible longer battery life.

[0082] The example of FIG. 13 provides an exemplary chart showing where the magnetic fields of adjacent magnet arms of a single multi-pole magnet assembly overlap. Such a configuration can result in many missed interrupts. The difference between FIG. 12 and FIG. 13 illustratively shows the effect of overlapping magnetic fields or cross-talking magnets. One possible cause of overlapping magnetic fields is that adjacent magnetic arms of a single multi-pole magnet assembly are too close to each other. Similarly, overlapping magnetic fields can also be experienced with magnetic encoders and ring magnets.

[0083] Other factors that may contribute to missed interrupts for magnetic encoders, ring magnets, and single multi-pole magnet assemblies include low magnetic field strength, which may be based on the proximity and magnetic strength of the magnetized sections. For example, the greater the distance between the magnetized sections and the Hall Effect sensor, the less sensitive the magnetic field strength measurement will be. Also, the lower the magnetic strength of the magnetic arms, the lower the magnetic field strength. One or a combination of these factors may compromise the magnetic encoder, ring magnet, and / or single multi-pole magnet assembly in such a way that all magnetic poles are not detected.

[0084] It should be understood that the exemplary embodiments described herein are subject to operational variations and alternative configurations for measuring dispensed medication. 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, or in combinations thereof. These components may be implemented as machine-readable storage devices for execution by, or to control the operation of, a data processing device, such as a processor, a computer, or multiple computers.

[0085] The various example logic blocks, modules, and circuits described in connection with the embodiments disclosed herein may be implemented or performed by a general purpose processor, a digital signal processor (DSP), an ASIC, an FPGA, or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but alternatively, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in combination with a DSP core, or any other such configuration.

[0086] Processors suitable for the execution of a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer. Generally, a processor receives instructions and data from a read-only memory or a random access memory or both. The essential elements of a computer are a processor for executing instructions and one or more memory devices for storing instructions and data. Generally, a computer also includes one or more mass storage devices for storing data, such as, for example, magnetic, magneto-optical, or optical disks, and is operatively coupled to receive data from them, transfer data to them, or both. Information carriers suitable for embodying computer program instructions and data include, by way of example, semiconductor memory devices such as Electrically Programmable Read Only Memory or ROM (EPROM), Electrically Erasable Programmable ROM (EEPROM), flash memory devices, and all forms of non-volatile memory, including data storage disks (magnetic disks, internal hard disks or removable disks, magneto-optical disks, CD-ROM and DVD-ROM disks, etc.). The processor and memory may be supplemented by, or incorporated in, special purpose logic circuitry.

[0087] Those skilled in the art will understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, the data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0088] Those skilled in the art will further appreciate that the various exemplary logic blocks, modules, circuits, and algorithm steps described in connection with the embodiments disclosed herein may be implemented, for example, as electronic hardware. The various exemplary components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality, and may be implemented by hardware depending on the particular application and design constraints imposed on the overall system. Those skilled in the art may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the claims as illustrated by the illustrated embodiments.

[0089] An exemplary storage medium is coupled to the processor such that the processor can read information from and write information to the storage medium. Alternatively, the storage medium may be integrated into the processor. In other words, the processor and the storage medium may reside within an integrated circuit or be implemented as separate components. Computer-readable non-transitory media include any type of computer-readable medium, including magnetic storage media, optical storage media, flash media, and solid-state storage media.

[0090] The above description and figures are intended to be examples only and are not intended to limit the illustrated embodiments in any way, except as set forth in the following claims. It is particularly noted that those skilled in the art can readily combine the 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 present invention.

Claims

1. 1. A drug delivery device comprising: a base plate engaging a cover to form an interior, the interior comprising: a pump drive mechanism for driving a drug through the device; a drive train engaged with the pump drive mechanism; a magnetic encoder including an encoder hub mechanically coupled to the drive train, the encoder hub including a magnet; a sensor that measures a magnetic field from the magnet to determine a rotational position of the drive train.

2. The drug delivery device of claim 1 , wherein the drug delivery device comprises one of a patch pump, an infusion pump, and an automated insulin delivery device.

3. The drug delivery device of claim 1 , wherein the pump drive mechanism includes a plunger driven by a lead screw.

4. the drive train includes a drive gear; the drive train engages a drive nut; and The drive nut is the final rotating component that engages the lead screw. The drug delivery device of claim 3.

5. The drug delivery device of claim 4 , wherein the drive gear is aligned with the sensor.

6. The drug delivery device of claim 4 , wherein the encoder hub is coupled to the drive gear to measure the rotational position.

7. The drug delivery device of claim 1 , wherein the magnet comprises a plurality of magnets equally spaced around the encoder hub.

8. 8. The drug delivery device of claim 7, wherein the polarity of the magnets facing away from the central axis of the drive gear remains constant.

9. 8. The drug delivery device of claim 7, wherein the polarities of the magnets facing away from a central axis of the drive gear alternate in series with respect to the drive gear.

10. The drug delivery device of claim 1 , wherein the magnet is axially polarized.

11. The drug delivery device of claim 1 , wherein the magnet is radially polarized.

12. The drug delivery device of claim 1 , wherein the magnet comprises a single multi-pole magnet with multiple equally spaced magnet arms.

13. The drug delivery device of claim 1 , wherein the sensor is mounted on a top surface of a circuit board.

14. The drug delivery device of claim 1 , wherein the sensor is mounted on a bottom surface of the circuit board.

15. The drug delivery device of claim 4 , wherein the sensor is aligned perpendicular to an axis of rotation of the drive gear.

16. The drug delivery device of claim 1 , wherein the sensor comprises one of a magnetic Hall effect sensor and a magnetoresistive sensor.

17. The drug delivery device of claim 1 , wherein the magnetic encoder comprises a ring magnet having one or more magnetized sections.

18. 1. A drug delivery device comprising: a base plate engaging a cover to form an interior, the interior comprising: a pump drive mechanism for driving a drug through the device; a drive train engaged with the pump drive mechanism; an optical sensor positioned relative to the drive train; Including, The optical sensor measures a rotational position of the drive train.

19. The drug delivery device of claim 18 , further comprising an optical sensor positioned relative to the drive train.

20. 20. The drug delivery device of claim 19, wherein the optical sensor includes an emitter that emits light including laser light and a receiver that receives the light.

21. the optical sensor includes an optical fan blade configured between an emitter and a receiver to split or block the light; 21. The drug delivery device of claim 20, wherein the optical sensor is configured to detect when the light is split or blocked.

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