Cam-driven rotary metering pump with valve shuttle interlock

Abstract

A rotary pump for a fluid metering system is disclosed. The rotary pump reciprocates and reverses in response to a signal from a limit switch deflected by an actuator arm on a rotating sleeve of the pump system. The rotary pump includes a plunger and optional stopper formed using a two-shot molding process, with seals overmolded onto the plunger head and optional stopper head.

Description

Technical Field

[0001] (Cross - Reference to Related Applications) This application is a continuation - in - part of U.S. Patent Application No. 15 / 300695, filed on September 29, 2016, which is the U.S. national stage of International Application No. PCT / US2015 / 024517, filed on April 6, 2015, which claims priority to U.S. Provisional Application No. 61 / 976361, filed on April 7, 2014, and is a related application to U.S. Patent Application No. 16 / 521685, filed on July 25, 2019. The application on which the priority is based is incorporated herein by reference as if the full text thereof were reproduced herein.

[0002] The present invention generally relates to a metering system for use in a wearable drug infusion patch.

Background Art

[0003] Diabetes is a group of diseases characterized by elevated blood glucose levels due to defects in insulin production, insulin action, or both. Diabetes can lead to serious complications and premature death, but there are well - known products available to diabetic patients to help control this disease and reduce the risk of complications.

[0004] Treatment options for diabetic patients include special diets, oral medications, and / or insulin therapy. The primary goal of diabetes treatment is to control the patient's blood glucose levels and increase the likelihood of a complication - free life. However, it is not always easy to achieve good diabetes management while balancing other life needs and circumstances.

[0005] Currently, there are two main modes of routine insulin therapy for the treatment of type 1 diabetes. The first mode generally involves syringes and insulin pens, which typically require needle pricking three or four times a day for each injection. Such devices are easy to use and relatively inexpensive. Another widely adopted and effective method of treatment for managing diabetes is the use of insulin pumps. Insulin pumps can help users keep their blood glucose levels within target ranges based on their individual needs by continuously infusing insulin at varying rates to more faithfully replicate the behavior of the pancreas. By using an insulin pump, users can adapt their insulin therapy to their lifestyle, rather than adapting their lifestyle to how insulin injections work for them. [Overview of the project] [Problems that the invention aims to solve]

[0006] However, conventional insulin pumps have several drawbacks. For example, the lead screw and piston type metering systems commonly used in insulin pumps require a large height and large footprint, making them often difficult for users to handle.

[0007] Furthermore, conventional insulin pumps generally require numerous parts and moving components, increasing the risk of mechanical failure.

[0008] Furthermore, conventional insulin pumps generally have tolerance loops that are too long for dose accuracy, relying on too many factors that can be difficult to verify. This can lead to a loss of dose accuracy.

[0009] Furthermore, conventional insulin pumps generally have overly complex fluid pathways. This can lead to complicated or inadequate priming and air removal.

[0010] Conventional insulin pumps also generally require high-precision actuators, which increases the cost of conventional patch pumps.

[0011] Furthermore, some insulin pumps pose a risk of creating a direct fluid pathway between the insulin patch reservoir and the cannula, potentially leading to user overdose.

[0012] Furthermore, conventional insulin pumps generally require complex detection methods. This can increase costs and potentially reduce accuracy and reliability.

[0013] Furthermore, conventional insulin pumps generally have valves that are prone to leaking due to increased system back pressure. This can lead to reduced accuracy and reliability.

[0014] Furthermore, conventional insulin pumps generally require large working and system volumes, which can potentially expose them to high back pressure. This can lead to reduced accuracy and reliability.

[0015] Furthermore, conventional insulin patches generally have low-efficiency motors that require large batteries, resulting in larger patch sizes.

[0016] Therefore, there is a need for a weighing system that enhances user comfort by reducing the height and footprint compared to conventional lead screw and piston type weighing systems.

[0017] Furthermore, a metering system is needed that reduces the number of parts and moving parts compared to conventional insulin pumps, thereby improving the mechanical safety of the insulin patch.

[0018] Furthermore, compared to conventional metering pumps, a metering system is needed that has a short tolerance loop for dose accuracy that depends on only a few factors, thereby improving dose accuracy.

[0019] In addition, compared with conventional metering systems, there is a need for a metering system that simplifies priming and air removal by having a simple fluid path.

[0020] In addition, compared with conventional metering systems, there is a need for a metering system that reduces the cost of insulin patches by using low-precision actuators.

[0021] In addition, compared with conventional metering systems, there is a need for a metering system that more appropriately protect users from over-intake by the absence of a direct fluid path between the reservoir and the cannula.

[0022] In addition, compared with conventional metering systems, there is a need for a metering system that reduces costs and improves the accuracy and reliability of insulin patches by having a simple detection method.

[0023] In addition, compared with conventional metering systems, there is a need for a metering system that improves the accuracy and reliability of insulin patches by having a valve that is robust against leakage at elevated system backpressure.

[0024] In addition, compared with conventional metering systems, there is a need for a metering system that improves the accuracy and reliability of insulin patches by having a small working volume and a small system volume that are potentially exposed to high backpressure.

[0025] In addition, compared with conventional metering systems, there is a need for a metering system that reduces the size of insulin patches by requiring a high-efficiency motor with a small battery.

Means for Solving the Problems

[0026] Aspects of exemplary embodiments of the present invention are to substantially address the above and other problems and provide a small and reliable metering system.

[0027] Aspects of exemplary embodiments of the present invention are to provide a metering system that enhances user comfort by reducing height and installation area compared to conventional parent screw and piston type metering systems.

[0028] Another aspect of exemplary embodiments of the present invention is to provide a metering system that increases the mechanical safety of insulin patches by reducing the number of parts and moving components compared to conventional insulin pumps.

[0029] Another aspect of exemplary embodiments of the present invention is to provide a metering system that improves dosing accuracy by having a short dosing accuracy tolerance loop that depends on few factors compared to conventional metering pumps. For example, in an exemplary embodiment of the present invention, the dosing accuracy tolerance loop is short and depends only on two easily measurable dimensions, namely the pump diameter and the axial dimension of the helical slot.

[0030] Another aspect of exemplary embodiments of the present invention is to provide a metering system that simplifies priming and air removal by having a simple fluid path compared to conventional metering systems.

[0031] Another aspect of exemplary embodiments of the present invention is to provide a metering system that reduces the cost of insulin patches by using low-precision actuators compared to conventional metering systems. For example, in an exemplary embodiment of the present invention, the mechanism rotates excessively at both ends of the stroke to continue maintaining dosing accuracy.

[0032] Another aspect of exemplary embodiments of the present invention is to provide a metering system that more appropriately protects the user from overconsumption by having no direct fluid path between the reservoir and the cannula compared to conventional metering systems.

[0033] Another embodiment of the exemplary embodiments of the present invention provides a weighing system that reduces costs and improves the accuracy and reliability of insulin patches by having a simpler detection method compared to conventional weighing systems. For example, in an exemplary embodiment of the present invention, the detection method is based on a contact switch.

[0034] Another exemplary embodiment of the present invention provides a metering system that enables easy activation of a cannula insertion mechanism by the mechanical stroke of a pump.

[0035] Another embodiment of the exemplary embodiments of the present invention provides a metering system that enhances the accuracy and reliability of insulin patches by having a valve that is robust against leakage in increased system back pressure compared to conventional metering systems. For example, in the exemplary embodiments of the present invention, the valve does not change in volume when moving between states.

[0036] Another exemplary embodiment of the present invention provides a weighing system that enhances the accuracy and reliability of insulin patches by having a small working volume and a small system volume, which are potentially exposed to higher back pressures compared to conventional weighing systems.

[0037] Another embodiment of the exemplary embodiments of the present invention provides a weighing system that reduces the size of an insulin patch by using a highly efficient motor with a smaller battery compared to conventional weighing systems.

[0038] The aforementioned and / or other aspects of the present invention are achieved by providing a metering system for use in a wearable insulin infusion patch. For example, in an exemplary embodiment of the present invention, the metering system is part of a larger fluid engineering subsystem comprising a flexible reservoir for containing insulin and a cannula assembly for delivering insulin to subcutaneous tissue. The metering system draws a small volume of fluid from the reservoir and then pushes it down into the cannula line for infusion into the patient. The fluid volume is small relative to the reservoir volume, and many pump strokes are required to completely empty the reservoir.

[0039] Additional and / or other aspects and advantages of the present invention are described in the following description, become apparent from the description, or may be understood by practice of the present invention. The present invention may include methods, apparatus, or systems having one or more of the above aspects and / or functions and / or combinations thereof. The present invention may include one or more of the above aspects and / or combinations thereof, such as those described in the appended claims. [Brief explanation of the drawing]

[0040] By reading the following detailed description in conjunction with the accompanying drawings, the various purposes, advantages, and novel features of the exemplary embodiments of the present invention will be more easily understood. [Figure 1] This figure shows the structure of an exemplary embodiment of the patch pump according to the present invention. [Figure 2] This figure shows the arrangement of fluid and metering system components in an exemplary embodiment of the patch pump according to the present invention. [Figure 3] This is a schematic exploded view of the metering subsystem of an exemplary embodiment of the patch pump according to the present invention. [Figure 4] This figure shows the arrangement of the metering subsystem in an exemplary embodiment of the patch pump according to the present invention. [Figure 5]This is a schematic cross-sectional view of the metering subsystem of an exemplary embodiment of the patch pump according to the present invention. [Figure 6A] These are multiple figures of the metering subsystem of an exemplary embodiment of a patch pump according to the present invention, in its starting position. [Figure 6B] These are multiple figures of the metering subsystem of an exemplary embodiment of a patch pump according to the present invention, in its starting position. [Figure 7A] These are multiple figures of the metering subsystem of an exemplary embodiment of the patch pump according to the present invention during the suction stroke. [Figure 7B] These are multiple figures of the metering subsystem of an exemplary embodiment of the patch pump according to the present invention during the suction stroke. [Figure 8A] These are multiple figures showing the valve state change after the suction stroke of the metering subsystem of an exemplary embodiment of the patch pump according to the present invention. [Figure 8B] These are multiple figures showing the valve state change after the suction stroke of the metering subsystem of an exemplary embodiment of the patch pump according to the present invention. [Figure 8C] These are multiple figures showing the valve state change after the suction stroke of the metering subsystem of an exemplary embodiment of the patch pump according to the present invention. [Figure 9A] These are multiple figures of the metering subsystem of an exemplary embodiment of a patch pump according to the present invention, in the suction movement stop position. [Figure 9B] These are multiple figures of the metering subsystem of an exemplary embodiment of a patch pump according to the present invention, in the suction movement stop position. [Figure 10A] These are multiple diagrams of the metering subsystem of an exemplary embodiment of the patch pump according to the present invention during the discharge stroke. [Figure 10B] These are multiple diagrams of the metering subsystem of an exemplary embodiment of the patch pump according to the present invention during the discharge stroke. [Figure 11A] These are multiple diagrams showing the valve state change after a discharge stroke in the metering subsystem of an exemplary embodiment of the patch pump according to the present invention. [Figure 11B]These are multiple diagrams showing the valve state change after a discharge stroke in the metering subsystem of an exemplary embodiment of the patch pump according to the present invention. [Figure 11C] These are multiple diagrams showing the valve state change after a discharge stroke in the metering subsystem of an exemplary embodiment of the patch pump according to the present invention. [Figure 12A] These are multiple diagrams of the metering subsystem of an exemplary embodiment of the patch pump according to the present invention, after the completion of the pump cycle. [Figure 12B] These are multiple diagrams of the metering subsystem of an exemplary embodiment of the patch pump according to the present invention, after the completion of the pump cycle. [Figure 13] This is an exploded view of the metering subsystem of an exemplary embodiment of the patch pump according to the present invention. [Figure 14] This is a schematic exploded view of a pump assembly of an exemplary embodiment of the metering pump according to the present invention. [Figure 15] This is a schematic exploded view of the motor and gearbox assembly of an exemplary embodiment of the metering pump according to the present invention. [Figure 16A] These are several schematic diagrams illustrating a method for incorporating a piston into a sleeve according to the present invention. [Figure 16B] These are several schematic diagrams illustrating a method for incorporating a piston into a sleeve according to the present invention. [Figure 16C] These are several schematic diagrams illustrating a method for incorporating a piston into a sleeve according to the present invention. [Figure 16D] These are several schematic diagrams illustrating a method for incorporating a piston into a sleeve according to the present invention. [Figure 17A] These are several schematic diagrams illustrating a method for incorporating a plug into a sleeve according to the present invention. [Figure 17B] These are several schematic diagrams illustrating a method for incorporating a plug into a sleeve according to the present invention. [Figure 17C] These are several schematic diagrams illustrating a method for incorporating a plug into a sleeve according to the present invention. [Figure 18A] These are several schematic diagrams illustrating a method for incorporating a sleeve into a manifold according to the present invention. [Figure 18B] These are several schematic diagrams illustrating a method for incorporating a sleeve into a manifold according to the present invention. [Figure 18C] These are several schematic diagrams illustrating a method for incorporating a sleeve into a manifold according to the present invention. [Figure 18D] These are several schematic diagrams illustrating a method for incorporating a sleeve into a manifold according to the present invention. [Figure 19] This is a schematic cross-sectional view of a pump assembly of an exemplary embodiment of a patch pump according to the present invention. [Figure 20A] These are several schematic cross-sectional views illustrating a method for changing the valve state according to the present invention. [Figure 20B] These are several schematic cross-sectional views illustrating a method for changing the valve state according to the present invention. [Figure 20C] These are several schematic cross-sectional views illustrating a method for changing the valve state according to the present invention. [Figure 20D] These are several schematic cross-sectional views illustrating a method for changing the valve state according to the present invention. [Figure 20E] These are several schematic cross-sectional views illustrating a method for changing the valve state according to the present invention. [Figure 21A] These are multiple diagrams of limit switches for pump and sleeve rotation in a metering subsystem of an exemplary embodiment of a patch pump according to the present invention. [Figure 21B] These are multiple diagrams of limit switches for pump and sleeve rotation in a metering subsystem of an exemplary embodiment of a patch pump according to the present invention. [Figure 21C] These are multiple diagrams of limit switches for pump and sleeve rotation in a metering subsystem of an exemplary embodiment of a patch pump according to the present invention. [Figure 22A] These are several schematic cross-sectional views illustrating a method for incorporating a pump into a gearbox according to the present invention. [Figure 22B] These are several schematic cross-sectional views illustrating a method for incorporating a pump into a gearbox according to the present invention. [Figure 22C]These are several schematic cross-sectional views illustrating a method for incorporating a pump into a gearbox according to the present invention. [Figure 23A] These are multiple figures of the metering subsystem of an exemplary embodiment of a patch pump according to the present invention, in its starting position. [Figure 23B] These are multiple figures of the metering subsystem of an exemplary embodiment of a patch pump according to the present invention, in its starting position. [Figure 23C] These are multiple figures of the metering subsystem of an exemplary embodiment of a patch pump according to the present invention, in its starting position. [Figure 24A] These are multiple diagrams of the metering subsystem of an exemplary embodiment of the patch pump according to the present invention during the discharge stroke. [Figure 24B] These are multiple diagrams of the metering subsystem of an exemplary embodiment of the patch pump according to the present invention during the discharge stroke. [Figure 25A] These are multiple diagrams showing the valve state change after a discharge stroke in the metering subsystem of an exemplary embodiment of the patch pump according to the present invention. [Figure 25B] These are multiple diagrams showing the valve state change after a discharge stroke in the metering subsystem of an exemplary embodiment of the patch pump according to the present invention. [Figure 25C] These are multiple diagrams showing the valve state change after a discharge stroke in the metering subsystem of an exemplary embodiment of the patch pump according to the present invention. [Figure 26A] These are multiple figures of the metering subsystem of an exemplary embodiment of the patch pump according to the present invention, in the discharge rotation stop position. [Figure 26B] These are multiple figures of the metering subsystem of an exemplary embodiment of the patch pump according to the present invention, in the discharge rotation stop position. [Figure 27A] These are multiple figures of the metering subsystem of an exemplary embodiment of the patch pump according to the present invention during the suction stroke. [Figure 27B] These are multiple figures of the metering subsystem of an exemplary embodiment of the patch pump according to the present invention during the suction stroke. [Figure 28A]These are multiple figures showing the valve state change after the suction stroke of the metering subsystem of an exemplary embodiment of the patch pump according to the present invention. [Figure 28B] These are multiple figures showing the valve state change after the suction stroke of the metering subsystem of an exemplary embodiment of the patch pump according to the present invention. [Figure 28C] These are multiple figures showing the valve state change after the suction stroke of the metering subsystem of an exemplary embodiment of the patch pump according to the present invention. [Figure 29A] These are multiple figures of the metering subsystem of an exemplary embodiment of the patch pump according to the present invention, in the suction rotation stop position. [Figure 29B] These are multiple figures of the metering subsystem of an exemplary embodiment of the patch pump according to the present invention, in the suction rotation stop position. [Figure 30A] These are multiple diagrams of the metering subsystem of an exemplary embodiment of the patch pump according to the present invention, after the completion of the pump cycle. [Figure 30B] These are multiple diagrams of the metering subsystem of an exemplary embodiment of the patch pump according to the present invention, after the completion of the pump cycle. [Figure 30C] These are multiple diagrams of the metering subsystem of an exemplary embodiment of the patch pump according to the present invention, after the completion of the pump cycle. [Figure 31A] These are several figures of an exemplary embodiment of a metering assembly according to the present invention, including a motor and gearbox assembly, and a modified pump assembly. [Figure 31B] These are several figures of an exemplary embodiment of a metering assembly according to the present invention, including a motor and gearbox assembly, and a modified pump assembly. [Figure 31C] These are several figures of an exemplary embodiment of a metering assembly according to the present invention, including a motor and gearbox assembly, and a modified pump assembly. [Figure 32] This is an exploded view of a pump assembly of an exemplary embodiment of the metering assembly according to the present invention. [Figure 33A]This figure shows how a piston is incorporated into a sleeve in an exemplary embodiment of the patch pump according to the present invention. [Figure 33B] This figure shows how a piston is incorporated into a sleeve in an exemplary embodiment of the patch pump according to the present invention. [Figure 34A] This figure shows how a sleeve is incorporated into a manifold in an exemplary embodiment of the patch pump according to the present invention. [Figure 34B] This figure shows how a sleeve is incorporated into a manifold in an exemplary embodiment of the patch pump according to the present invention. [Figure 34C] This figure shows how a sleeve is incorporated into a manifold in an exemplary embodiment of the patch pump according to the present invention. [Figure 34D] This figure shows how a sleeve is incorporated into a manifold in an exemplary embodiment of the patch pump according to the present invention. [Figure 34E] This figure shows how a sleeve is incorporated into a manifold in an exemplary embodiment of the patch pump according to the present invention. [Figure 35] This is a cross-sectional view of a sleeve and manifold assembly of an exemplary embodiment of a patch pump according to the present invention. [Figure 36A] These are multiple cross-sectional views illustrating the valve state changes of an exemplary embodiment of the patch pump according to the present invention as the sleeve rotates. [Figure 36B] These are multiple cross-sectional views illustrating the valve state changes of an exemplary embodiment of the patch pump according to the present invention as the sleeve rotates. [Figure 36C] These are multiple cross-sectional views illustrating the valve state changes of an exemplary embodiment of the patch pump according to the present invention as the sleeve rotates. [Figure 37A] This figure shows a sleeve rotation limit switch in an exemplary embodiment of the patch pump according to the present invention. [Figure 37B] This figure shows a sleeve rotation limit switch in an exemplary embodiment of the patch pump according to the present invention. [Figure 37C]This figure shows a sleeve rotation limit switch in an exemplary embodiment of the patch pump according to the present invention. [Figure 37D] This figure shows a sleeve rotation limit switch in an exemplary embodiment of the patch pump according to the present invention. [Figure 38A] This is an exploded view of a pump assembly of an exemplary embodiment of a patch pump according to the present invention, with the elastomer port and piston seal overmolded onto the manifold and pump piston, respectively. [Figure 38B] This is an exploded view of a pump assembly of an exemplary embodiment of a patch pump according to the present invention, with the elastomer port and piston seal overmolded onto the manifold and pump piston, respectively. [Figure 39A] This is an exploded view of a pump assembly having an alternative rotation limit switch design, representing an exemplary embodiment of a patch pump according to the present invention. [Figure 39B] This is an exploded view of a pump assembly having an alternative rotation limit switch design, representing an exemplary embodiment of a patch pump according to the present invention. [Figure 39C] This is an exploded view of a pump assembly having an alternative rotation limit switch design, representing an exemplary embodiment of a patch pump according to the present invention. [Figure 39D] This is an exploded view of a pump assembly having an alternative rotation limit switch design, representing an exemplary embodiment of a patch pump according to the present invention. [Figure 40] This figure shows the structure of an exemplary embodiment of the weighing assembly according to the present invention. [Figure 41] Figure 40 is an assembly diagram of the weighing assembly. [Figure 42] Figure 40 is a cross-sectional view of the weighing assembly. [Figure 43A] This figure shows an exemplary embodiment illustrating the interaction between the sleeve and interlock of the weighing assembly according to the present invention. [Figure 43B] This figure shows an exemplary embodiment illustrating the interaction between the sleeve and interlock of the weighing assembly according to the present invention. [Figure 43C] This figure shows an exemplary embodiment illustrating the interaction between the sleeve and interlock of the weighing assembly according to the present invention. [Figure 44] This is a cross-sectional view of another exemplary embodiment of the weighing assembly according to the present invention. [Figure 45] This is an isometric view of a limit switch and actuator arm useful in another exemplary embodiment of the present invention. [Figure 46] Figure 45 is an isometric view of the limit switch and rotary sleeve according to the embodiment shown. [Figure 47] Figure 45 is a top view of the limit switch. [Figure 48] Figure 45 is a top view of the limit switch and actuator arm. [Figure 49] Figure 46 is an end view of the rotating sleeve. [Figure 50] Figure 45 is a cross-sectional elevation view of the limit switch and actuator arm. [Figure 51A] This figure shows the relative displacement of a limit switch and a rotating sleeve according to an exemplary embodiment of the present invention. [Figure 51B] This figure shows the relative displacement of a limit switch and a rotating sleeve according to an exemplary embodiment of the present invention. [Figure 52] This is a different perspective view of an improved plunger for a pump according to another exemplary embodiment of the present invention. [Figure 53] This is a different perspective view of an improved plunger for a pump according to another exemplary embodiment of the present invention. [Figure 54] This is a different perspective view of an improved plunger for a pump according to another exemplary embodiment of the present invention. [Figure 55] This is a different perspective view of an improved plunger for a pump according to another exemplary embodiment of the present invention. [Figure 56] This is a different perspective view of an improved plunger for a pump according to another exemplary embodiment of the present invention. [Figure 57]This is a different perspective view of an improved plunger for a pump according to another exemplary embodiment of the present invention. [Figure 58] This is a different perspective view of an improved plunger for a pump according to another exemplary embodiment of the present invention. [Figure 59] Figures 52-58 show different perspective views of the overmolded seal for the improved plunger. [Figure 60] Figures 52-58 show different perspective views of the overmolded seal for the improved plunger. [Figure 61] Figures 52-58 show different perspective views of the overmolded seal for the improved plunger. [Figure 62] Figures 52-58 show different perspective views of the overmolded seal for the improved plunger. [Figure 63] Different perspectives of the improved pump plug. [Figure 64] Different perspectives of the improved pump plug. [Figure 65] Different perspectives of the improved pump plug. [Figure 66] Different perspectives of the improved pump plug. [Figure 67] Different perspectives of the improved pump plug. [Figure 68] This is an exploded view of a pump system utilizing an improved plunger, plug, and overmolded seal according to an exemplary embodiment of the present invention. [Figure 69] This is a flowchart of a method for manufacturing a pump according to an exemplary embodiment of the present invention. [Figure 70A] This figure shows another exemplary embodiment of the present invention. [Figure 70B] This figure shows another exemplary embodiment of the present invention. [Figure 70C] This figure shows another exemplary embodiment of the present invention. [Figure 70D] This figure shows another exemplary embodiment of the present invention. [Figure 70E]This figure shows another exemplary embodiment of the present invention. [Figure 70F] This figure shows another exemplary embodiment of the present invention. [Figure 70G] This figure shows another exemplary embodiment of the present invention. [Figure 70H] This figure shows another exemplary embodiment of the present invention. [Figure 70I] This figure shows another exemplary embodiment of the present invention. [Figure 70J] This figure shows another exemplary embodiment of the present invention. [Figure 70K] This figure shows another exemplary embodiment of the present invention. [Figure 70L] This figure shows another exemplary embodiment of the present invention. [Figure 71] This is an exploded view of an output gear and shuttle assembly according to an exemplary embodiment of the present invention. [Figure 72A] This illustrates the interaction between the cam and the shuttle according to an exemplary embodiment of the present invention. [Figure 72B] This illustrates the interaction between the cam and the shuttle according to an exemplary embodiment of the present invention. [Figure 72C] This illustrates the interaction between the cam and the shuttle according to an exemplary embodiment of the present invention.

[0041] Throughout the drawings, similar reference numbers should be understood to refer to similar elements, features, and structures. [Modes for carrying out the invention]

[0042] As will be understood by those skilled in the art, there are many ways of carrying out the examples, improvements, and arrangements of weighing systems according to the embodiments of the present invention disclosed herein. While referring to the exemplary embodiments shown in the drawings and the following description, those skilled in the art will readily understand that the embodiments disclosed herein are not exhaustive of the various alternative designs and embodiments encompassed by the disclosed invention, and that various modifications and combinations may be made without departing from the present invention.

[0043] While not limited to patients or healthcare professionals, various people, including patients or healthcare workers, may operate or use exemplary embodiments of the present invention, for the sake of brevity, the operator or user will be referred to as "user" below.

[0044] In exemplary embodiments of the present invention, various fluids may be used, but for simplicity, the liquid in the injection device will be referred to as the "fluid" below.

[0045] Exemplary embodiments of the present invention are shown in Figures 1 to 30. In an exemplary embodiment of the present invention, a metering system for use in a wearable insulin infusion patch is provided. For example, in an exemplary embodiment of the present invention, the metering system is part of a larger fluid engineering subsystem comprising a flexible reservoir for containing insulin and a cannula assembly for delivering insulin to subcutaneous tissue. The metering system draws a small volume of fluid from the reservoir and then pushes it down into the cannula line into the patient. The fluid volume is small relative to the reservoir volume, and many pump strokes are required to completely empty the reservoir.

[0046] Figure 1 shows the structure of a patch pump 100 according to an exemplary embodiment of the present invention. The patch pump 100 comprises a fluid engineering subsystem 120, an electronics subsystem 140, and a power storage subsystem 160.

[0047] The fluid engineering subsystem 120 includes a filling port 122 that is in fluid communication with a reservoir 124. The reservoir 124 is configured to receive fluid from a syringe through the filling port.

[0048] The fluid dynamics subsystem 120 further comprises a volume sensor 126 mechanically connected to the reservoir 124. The volume sensor 126 is configured to detect or determine the amount of fluid in the reservoir.

[0049] The fluid engineering subsystem 120 further comprises a metering subsystem 130 which includes an integrated pump and valve system 132 mechanically coupled to a pump and valve actuator 134. The integrated pump and valve system 132 is in fluid communication with a reservoir 124 of the fluid engineering subsystem 120 and is actuated by the pump and valve actuator 134.

[0050] The fluid engineering subsystem 120 further comprises a cannula mechanism having a deployment actuator 128 mechanically connected to a cannula 129. The deployment actuator 128 is configured to insert the cannula 129 into the user. The cannula 129 is in fluid communication with an integrated pump and valve system 132 of the metering subsystem 130.

[0051] The fluid engineering subsystem 120 further comprises an obstruction sensor 136 mechanically connected to the fluid path between the cannula 129 and an integrated pump and valve system 132. The obstruction sensor 136 is configured to detect or determine an obstruction in the path between the cannula 129 and the integrated pump and valve system 132.

[0052] The electronic subsystem 140 comprises a quantity sensing electronic device 142 electrically connected to the quantity sensor 126 of the fluid engineering subsystem 120, a pump and valve controller 144 electrically connected to the pump and valve actuator 134 of the metering subsystem 130, an obstruction detection electronic device 146 electrically connected to the obstruction sensor 136 of the fluid engineering subsystem 120, and an optional deployment electronic device 148 electrically connected to the cannula 129 of the fluid engineering subsystem. The electronics subsystem 140 further comprises a microcontroller 149 electrically connected to the quantity sensing electronic device 142, the pump and valve controller 144, the obstruction detection electronic device 146, and the deployment electronic device 148.

[0053] The power storage subsystem 160 comprises a battery 162 or other power source known in the art. The battery 162 may be configured to supply power to any element or electronic component of the patch pump 100.

[0054] Figure 2 shows the arrangement of fluid and metering system components of a patch pump 200 according to an exemplary embodiment of the present invention. The patch pump 200 comprises a metering subsystem 230, control electronics 240, a battery 260, a reservoir 222, a filling port 224, and a cannula mechanism 226. The elements of the patch pump 200 are substantially similar to and interact substantially similarly with the elements of the exemplary patch pump 100, which are indicated by similar reference numerals.

[0055] Figure 3 is an exploded view of a metering subsystem 300 of a patch pump according to an exemplary embodiment of the present invention. The metering subsystem 300 comprises a DC gear motor 302 mechanically coupled to a pump piston 304 located within a pump casing 306. The pump piston 304 is mechanically coupled to a pump housing 308 by a coupling pin 310. The metering subsystem 300 further comprises a pump seal 312 between the pump piston 304 and the pump housing 308. The metering subsystem 300 further comprises a port seal 314 on a seal carriage 316 located within a valve housing 318.

[0056] In an exemplary embodiment of the present invention, the output shaft 320 of the DC gear motor can rotate 360° in either direction. The pump piston 304 can rotate 360° in either direction and can translate approximately 0.050 inches (0.127 cm). The pump housing 308 can rotate 180° in either direction. The pump casing 306, port seal 314, seal carriage 316, and valve housing 318 are preferably fixed.

[0057] The metering subsystem 300 comprises a positive displacement pump having an integrated flow control valve and a mechanical actuator and drive system. The pump comprises a piston 304 and a rotaryly actuated switching valve. The metering system administers insulin in small individual doses by drawing a precise amount of insulin from a flexible reservoir into a pump volume 320 (see Figure 5) formed between the piston 304 and the pump housing 308, and then discharging this amount of insulin into the patient's subcutaneous tissue through a cannula. The pump stroke induces flow by creating positive and negative pressure gradients in the fluid path. The stroke and the inner diameter of the pump volume determine the nominal size and dose accuracy. The fluid control valve actively reciprocates between the reservoir and the cannula fluid port at each end of the pump stroke, alternately closing and opening the port, thereby ensuring that the fluid flow is unidirectional (from reservoir to patient) and that there is no possibility of free flow between the reservoir and the patient.

[0058] Figure 4 is an assembly drawing of a metering subsystem 300 according to an exemplary embodiment of the present invention. The motor-to-piston connection 322, the piston-to-pump housing connection 324, the reservoir port 326, and the cannula port 328 are also shown.

[0059] Figure 5 is a cross-sectional view of a metering subsystem 300 of an exemplary embodiment of the present invention. As shown, a pump volume 320 is formed between the piston and the pump housing 308. As will be described in more detail below, the pump housing includes side ports 330 which alternate in orientation between the reservoir port 326 and the cannula port 328 when the motor 302 reciprocates the pump.

[0060] During operation, an exemplary cycle of the metering system according to the present invention includes four steps: a 180° pump inlet (counterclockwise) (when viewed from the pump towards the motor), a 180° valve state change (counterclockwise), a 180° pump discharge (clockwise), and a 180° valve state change (clockwise). The entire cycle requires a full rotation (360°) in each direction.

[0061] Figure 6A is an isometric view, and Figure 6B is a cross-sectional view of the metering subsystem 300 in the starting position. In the starting position, the pump piston 302 is fully extended, the pump housing closes the cannula receptacle 328 to the cannula receptacle flow path, the reservoir port 326 opens to the side port 330 of the pump housing 308, and the rotation limit sensor 332 is engaged. The pump housing 308 is provided with a helical groove 334 that receives the connecting pin 310. The piston 304 slides with the pump housing 308, and as the piston 304 rotates within the pump housing 308 (by the rotational force of the motor 302), the connecting pin 310 slides along the helical groove 334, causing the piston 304 to translate axially relative to the pump housing 308. In this embodiment, the helical groove 334 is formed within the pump housing 308 and provides 180° rotation of the connecting pin 310.

[0062] Figure 7A is an isometric view, and Figure 7B is a cross-sectional view of the metering subsystem 300 during the suction stroke. The DC motor 302 rotates the pump piston 304, which is driven (rotational and translational) along the helical groove 334 of the pump housing 308 via a connecting pin 310. The pump piston 304 translates toward the DC motor 302, drawing fluid into the expanding pump volume 320. During the suction stroke, it is preferable that the friction between the seal and the outer diameter of the pump housing 308 is sufficiently high to ensure that the pump housing 308 does not rotate. The pump housing 308 is fixed, and the pump volume 320 is expanded. The cannula port 328 is closed, and the reservoir port 326 is open to the fluid flowing into the expanded pump volume 320. The motor 302 and the pump piston 304 are in sliding engagement.

[0063] Figure 8A is an assembly diagram, Figure 8B is a detailed view, and Figure 8C is a cross-sectional view of the patch pump during valve state change after the suction stroke. Torque is transmitted from the drive shaft of the motor 302 to the pump piston 304, and then to the pump housing 308 via the connecting pin 310. When the connecting pin 310 rotates to the end of the helical groove 334, further rotation of the motor 302 causes the connecting pin 310 to rotate the pump housing 308 and the pump piston 304 together as a single unit without relative axial translational motion. The side port 330 of the pump housing 308 rotates between the reservoir port 326 and the cannula port 328. The surface tension of the side port 330 of the pump housing 308 holds the fluid within the pump volume 320. The side port 330 of the pump housing de-aligns with the reservoir port 326 and aligns with the cannula port 328 over the next 180° rotation of the motor 302. During this time, both the cannula port 328 and the reservoir port 326 are closed. The connecting pin 310 is located at the end of the helical groove 334 and transmits torque to the pump housing 308. The connecting pin 310 locks the pump piston 304 and the pump housing 308 together, preventing relative axial movement between the two parts. Thus, the pump piston 304 and the pump housing 308 rotate as a single unit and do not translate relative to each other. The pump housing 308 rotates, the pump volume 320 remains constant, and the pump piston 304 rotates. Preferably, the seal 314, the seal carriage, and the valve housing 318 are fixed.

[0064] Figure 9A is an assembly diagram, and Figure 9B is a cross-sectional view of the metering subsystem ready for injection, in the suction movement stop position. As shown, the side port 330 of the pump housing 308 is aligned with the cannula port 328, the pump volume 320 expands, and the reservoir port 326 closes. The rotation limit sensor 332 engages with the function on the rotating pump housing 308. The motor 302, pump piston 304, and pump housing 308 are fixed.

[0065] Figure 10A is an assembly diagram, and Figure 10B is a cross-sectional view of the metering subsystem 300 during the discharge stroke. At the end of the suction stroke, the DC motor 302 switches direction as the pump housing 308 engages with the limit switch 332. Thus, the motor 302 rotates the piston 304, pushing the connecting pin 310 down along the helical groove 334 of the pump housing 308, causing the piston 304 to translate axially. The pump piston 304 translates axially away from the DC motor 302, pushing the fluid out of the pump volume 320 to the cannula out of the cannula port 328. During the discharge stroke, it is preferable that the friction between the seal 314 and the outer diameter of the pump housing 308 is sufficiently high to ensure that the pump housing 308 does not rotate. The cannula port 328 is open to the fluid flowing out of the collapsed pump volume 320. The reservoir port 326 is closed. The pump housing 308 is fixed, the pump volume 320 is compressed, and the pump piston 304 rotates and translates in a helical motion. A motor is slidably connected to the piston 304 and corresponds to the translational motion of the piston as it rotates within the helical groove 334.

[0066] Figure 11A is an assembly diagram, Figure 11B is a detailed view, and Figure 11C is a cross-sectional view of the metering subsystem 300 during valve state change after the discharge stroke. Torque is transmitted from the drive shaft of the motor 302 to the pump piston 304, and then to the pump housing 308 via the connecting pin 310. The pump housing 308 and the pump piston 304 rotate as a single unit without relative axial motion. The side port 330 of the pump housing 308 rotates between the reservoir port 326 and the cannula port 328, both of which close during rotation. The surface tension of the side port 330 of the pump housing 308 holds the fluid within the pump volume 320. The connecting pin 310 locks the pump piston 304 and the pump housing 308 together, preventing relative axial motion between the two parts. Thus, the pump piston 304 and the pump housing 308 rotate as a single unit and do not translate relative to each other. The pump housing 308 rotates, while the pump volume 320 remains constant. Preferably, the seal 314, seal carriage, and valve housing 318 are fixed.

[0067] Figure 12A is an assembly diagram, and Figure 12B is a cross-sectional view of the metering subsystem 300 after the pump cycle is complete. The pump mechanism (piston 304) is fully extended, completing the pump cycle. The rotation limit sensor 332 engages, reversing the motor 302 and restarting the pump cycle. The cannula port 328 is closed, and the reservoir port 326 is open to the flow path from the reservoir.

[0068] In the exemplary embodiment described above, the pump piston rotates and translates, the pump housing rotates, and the valve housing is fixed. However, it should be understood that in other embodiments, the system may be configured such that the pump volume increases or decreases by the rotation of the pump piston, the rotation and translation of the pump housing, the translation of the valve housing, or some other combination of motions, and the port moves in communication with the pump volume from alignment with the reservoir port to alignment with the cannula port.

[0069] In the exemplary embodiment described above, the pump stroke and valve state change are constituted by a 180° rotational operation from the motor. However, it should be understood that any appropriate angle may be selected for the segment of the pump cycle.

[0070] In the exemplary embodiments described above, there is atmospheric isolation between the cannula and the reservoir port during valve state changes. However, it should be understood that in other embodiments, a seal may be configured or an additional seal may be added to eliminate atmospheric isolation and seal the pump and valve system during state changes.

[0071] In the exemplary embodiments described above, a DC gear motor is used to drive the pump and valve. However, in other embodiments, any suitable drive mechanism may be provided to drive the pump and valve. For example, a solenoid, a nitinol wire, a voice coil actuator, a piezoelectric motor, a wax motor, and / or any other type of motor known in the art may be used to drive the pump.

[0072] In the exemplary embodiment described above, the pump uses the full discharge stroke. However, it should be understood that in other embodiments, a system with sequentially increasing discharge strokes may be used to dispense finer doses.

[0073] In the exemplary embodiment described above, the pump uses an on / off limit switch to determine the system state at the limit of rotational movement. However, it should be understood that in other embodiments, the resolution of the detection method may be improved by using other sensors capable of determining intermediate states, such as encoder wheels and optical sensors.

[0074] Please understand that the pump's inner diameter may be adjusted to vary the nominal output with each cycle.

[0075] In the exemplary embodiment described above, the pump uses an elastomer O-ring seal. However, it should be understood that other arrangements may be used. For example, the fluid seal may be molded directly onto the seal carriage, or other elastomer seals such as 4-rings may be used, or other sealing materials such as Teflon or polyethylene lip seals may be used.

[0076] In an alternative embodiment of the present invention, the movement of a pump may be used to initiate or start the deployment of the cannula.

[0077] In the aforementioned example, it is advantageous for the system to use bidirectional operation. The motor rotation is reversed so that the suction stroke and discharge stroke alternate. This provides a safety feature that prevents runaway operation in the event of motor malfunction. The motor must reciprocate to ensure that the pump continues to deliver the drug from the reservoir. However, it should be understood that in other embodiments, the metering system is designed to use a unidirectional actuator.

[0078] In the exemplary embodiment described above, the system uses a pouch reservoir having two flexible walls. However, in other embodiments, the reservoir may be formed in any suitable way including one rigid wall and one flexible wall.

[0079] Figure 13 is an exploded view of a metering subsystem 1300 of a patch pump according to another exemplary embodiment of the present invention. The metering subsystem 1300 comprises a motor and gearbox assembly 1302 and a pump assembly 1304.

[0080] Figure 14 is an exploded view of the pump assembly 1304. The pump assembly 1304 comprises a piston 1306 mechanically connected to a sleeve 1308 by a connecting pin 1310 within a pump manifold 1312. The pump assembly 1304 further comprises a port seal 1314, a plug 1316, a sleeve rotation limit switch 1318, and an output gear rotation limit switch 1320.

[0081] The piston 1306 can rotate a total of 196° in either direction and translate approximately 0.038 inches (0.09652 cm). The sleeve 1308 and plug 1316 together (as a pair) rotate 56° in either direction. The pump manifold 1312 and port seal 1314 are fixed in place.

[0082] Figure 15 is an exploded view of the motor and gearbox assembly 1302. The motor and gearbox assembly 1302 comprises a gearbox cover 1322, a compound gear 1324, an output gear 1326, a spindle 1328, a gearbox base 1330, a motor pinion gear 1332, and a DC motor 1334.

[0083] Figures 16A to 16D show the assembly and operation of the piston 1306, sleeve 1308, and connecting pin 1310. Figure 16A shows the piston 1306, which includes a press-fit hole 1338 for receiving the connecting pin 1310 and a piston seal 1340 for tightly sealing the piston within the sleeve 1308. The sleeve 1308 includes a helical groove 1342. The piston 1306 is pushed axially into the sleeve 1308, and then the connecting pin 1310 is press-fitted into the hole 1338 through the helical groove 1342. This results in the same operation as in the previously described embodiment, where, as the piston 1306 rotates, the interaction between the connecting pin 1310 and the helical groove 1342 causes the piston 1306 to translate axially relative to the sleeve 1308. Figure 16B shows the assembled piston 1306, sleeve 1308, and connecting pin 1310, with the connecting pin 1310 located at the lower end of the helical groove 1342. Figure 16C shows the axial stroke length 1344 of the piston 1306 relative to the sleeve 1308 as a result of the helical groove 1342. Figure 16D shows a tapered surface 1346, preferably located at the end of the helical groove 1342, which centers the connecting pin 1310 within the groove 1342.

[0084] Figure 17A shows the assembly of the plug 1316 and the sleeve 1308. As illustrated, the plug 1316 comprises a key 1346 and a seal 1348. The seal 1348 provides an interlocking fit for the plug within the sleeve 1308. The sleeve 1308 includes a recess 1350 configured to receive the key 1346. The key 1346 rotates and locks the plug 1316 with the sleeve 1308. During assembly, the plug 1316 is pressed against the end face of the (advancing) piston 1306 to minimize air in the pump chamber. Friction between the seal 1348 and the inner surface of the sleeve 1308 holds the plug 1316 axially. By appropriately selecting the seal diameter, compression, and material, the plug 1316 can also function as a blockage or overpressure sensor. Pump pressure above a threshold causes the plug 1316 to move axially, disengaging it from the sleeve rotation limit switch 1318. Friction holds the plug 1316 in a position that resists pressure below a desired threshold. Figures 17B and 17C show the axial movement of the piston 1306 within the sleeve 1308. Figure 17B shows the piston 1306 in a first state where the pump volume between the piston 1306 and the plug 1316 is minimal or nonexistent. As illustrated, the connecting pin 1310 abuts against the lowest end of the helical groove 1342. Figure 17C shows the piston 1306 in a second state where the pump volume 1352 between the piston 1306 and the plug 1316 is maximum. As illustrated, the connecting pin 1310 abuts against the uppermost end of the helical groove 1342.

[0085] Figures 18A to 18D show the assembly of the sleeve 1308 into the manifold 1312. As shown in Figure 18A, the manifold 1312 includes port seals 1314 for sealing the reservoir port 1354 and the cannula port 1356, respectively. A small side hole 1358 of the sleeve (see Figure 17B) rotates and reciprocates between the two ports, which are 56 degrees apart. As shown in Figure 18B, the sleeve 1308 includes a tab 1360, and the manifold 1312 includes a corresponding slot 1362 into which the sleeve 1308 can be assembled. Figure 18C shows a manifold window 1364 provided in the manifold. When the sleeve 1308 is assembled into the manifold 1312, the tab 1360 is received into the window 1364 and moves within the window 1364. Tab 1360 and window 1364 interact to allow sleeve 1308 to rotate between two positions and to prevent axial translational motion of sleeve 1308 relative to manifold 1312. Sleeve 1308 rotates between a first position in which the side hole 1358 is aligned with reservoir port 1354 and a second position in which the side hole 1358 is aligned with cannula port 1356. Figure 18D shows sleeve 1308 incorporated into manifold 1312 with tab 1360 positioned within manifold window 1364.

[0086] Figure 19 is a cross-sectional view of the assembled weighing system. As shown, the port seal 1314 is a surface seal compressed between the OD of the sleeve 1308 and the recessed pocket of the manifold 1312. Also shown, the tab 1360 is located within the manifold window 1364, and the side hole 1358 is shown in the transition state between the reservoir port 1354 and the cannula port 1356. The output gear 1326 has a cam function 1366 that engages with the rotation limit switch 1320 to signal the end of rotational movement in either direction of the piston 1306 and the sleeve 1308.

[0087] Figures 20A to 20E are cross-sectional views showing the rotation of the sleeve 1308 within the manifold 1312 to move the side hole from alignment with the reservoir port 1354 to alignment with the cannula port 1356. Figure 20A shows the side hole 1358 aligned with the reservoir port 1354. In this position, the piston 1306 moves away from the plug 1316 and fills the volume 1352 with fluid from the reservoir. Figure 20B shows the sleeve 1308 as it begins to rotate toward the cannula port 1356. In this position, the side hole 1358 is sealed by the seal 1314 of the reservoir port 1354. For this purpose, the diameters of the seal 1314 and the side hole 1358 are preferably selected so that the seal 1314 covers the opening of the side hole 1358. Figure 20C shows the side hole 1358 of the sleeve 1308 between the seal 1314 of the reservoir port 1354 and the seal 1314 of the cannula report 1356. In this position, neither seal 1314 closes the side hole 1358, but the surface tension of the fluid holds the fluid in the pump chamber. Figure 20D shows the side hole 1358 rotated further so that the seal 1314 of the cannula report 1356 covers the opening of the side hole 1358. Finally, Figure 20E shows the side hole 1358 rotated and aligned with the cannula report 1356. While in this position, the piston 1306 translates axially, reducing the volume 1352 and pushing the fluid out of the cannula report 1356 towards the cannula.

[0088] Figures 21A and 21C illustrate the operation of the limit switch. As shown in Figure 21A, the plug 1316 is equipped with a cam function 1368 that interacts with the limit switch 1318. As the sleeve 1308 and plug 1316 rotate, the cam function 1368 causes the metal bends of the limit switch 1318 to contact each other until the plug 1316 has fully rotated to the next position. When the plug 1316 is at any endpoint of the plug rotation, one of the protrusions 1370 of the bend is placed within the cam function 1368, as shown in Figure 21C. The limit switch 1318, which opens and closes each rotational cycle, signals that the plug 1316 remains properly aligned with the limit switch 1318. In an overpressure or blockage condition, the increased pressure causes the plug 1316 to slide out of the sleeve 1308 and lose alignment with the limit switch 1318. This detects the overpressure condition. At the end of each rotational cycle, the cam function 1366 of the output gear 1326 engages with the limit switch 1320. This signals the motor 1334 to reverse direction. As illustrated, the two metal bends prevent the limit switch from determining which rotational cycle has been completed. However, as can be understood, the third bend allows for the determination of the direction of engagement.

[0089] Figures 22A and 22C show the assembly of the motor and gearbox 1302 and the pump assembly 1304. As shown in Figures 22A and 22B, the motor and gearbox 1302 includes an opening 1372 for receiving a rotation limit switch 1320. In this way, the output gear 1326 located inside the gearbox housing can access and engage with the bend of the limit switch 1320. The motor and gearbox 1302 also includes an axial retaining snap 1374 to allow the pump assembly 1304 to snap into the motor and gearbox 1302. The motor and gearbox 1302 includes a rotary key 1376 in a pump receiving socket 1378 to receive the pump assembly 1304 and prevent the pump assembly 1304 from rotating relative to the motor and gearbox 1302. The output gear 1326 includes a slot 1380 (Figure 22B) configured to receive a tab 1382 (Figure 22C) provided on the piston 1306. Once assembled, tab 1382 is positioned within slot 1380, allowing output gear 1326 to transmit torque to piston 1306. As output gear 1326 rotates, pump piston tab 1382 rotates and slides axially within the slot. A metal spring bend and limit switch at the motor connection point are used to make electrical contact with the circuit board pads during final assembly.

[0090] During operation, the pump cycle of the aforementioned embodiment includes five steps: firstly, approximately 120° of pump discharge (counterclockwise when viewed from the pump towards the gearbox), 56° of valve state change (counterclockwise), 140° of pump suction (clockwise), 56° of valve state change (clockwise), and approximately 20° of slight oscillation (counterclockwise) to clear the limit switch. The entire pump cycle requires 196° of output gear rotation in each direction.

[0091] Figures 23A to 30C show the pump cycle. For clarity, only the output gear 1326 of the gearbox assembly 1302 is shown.

[0092] Figure 23A shows the starting position. As illustrated, the cam 1366 of the output gear 1326 is not in contact with the rotation limit switch 1320, and the bends are not in contact with each other. The pump piston 1306 retracts, as indicated by the position of the connecting pin 1310 in the helical groove 1342 in Figure 22C. In this position, the sleeve 1308 closes the reservoir passage, the cannula port 1356 opens to the side hole 1358 of the sleeve 1308, and both the rotation limit sensor 1320 and the sleeve sensor 1318 (see Figure 23B) are open.

[0093] Figures 24A and 24B show the metering subsystem during the discharge stroke. The output gear 1326 rotates the pump piston 1306 in a first rotational direction (see arrow in Figure 24B), which is driven along the helical path of the helical groove 1342 of the sleeve 1308 via the connecting pin 1310 (see Figure 24A). The pump piston 1306 translates away from the gearbox during rotation, discharging the fluid from the pump chamber 1352 to the cannula port 1356. During the discharge stroke, the friction between the port seal 1314 and the outer diameter of the sleeve 1308 should be high enough to ensure that the sleeve 1308 does not rotate during this part of the cycle.

[0094] Figures 25A to 25C show the metering subsystem during valve state change after the discharge stroke. As shown in Figure 25A, after the connecting pin 1310 reaches the distal end of the helical groove 1342, torque is transmitted from the output gear 1326 to the pump piston 1306 and then to the sleeve 1308 via the connecting pin 1310. The sleeve 1308 and the pump piston 1306 rotate as a single unit without relative axial motion. The side hole 1358 of the sleeve 1308 (not shown in Figures 25A to 25C) moves between the reservoir port 1354 and the cannula port 1356. The tab 1360 moves in the direction indicated by the arrow within the window 1364 of the manifold 1312. As shown in Figure 25B, the sleeve limit switch 1318 is closed by the cam surface of the plug 1316.

[0095] Figures 26A and 26B show the metering subsystem in the discharge rotation stop position. The sleeve side hole 1358 (not shown in Figure 26A or 26B) is aligned with the reservoir port 1354, the pump volume 1352 is compressed, and the cannula port 1356 is closed. The plug 1316 is in the stop position and the sleeve limit switch 1318 is open. The output gear cam 1366 contacts the rotation limit switch 1320 to signal the end of rotation, causing the output gear 1326 to stop and reverse direction.

[0096] Figures 27A and 27B show the metering subsystem during the suction stroke. The output gear 1326 rotates the pump piston 1306 in the direction indicated by the arrow in Figure 27B. The piston 1306 translates axially relative to the sleeve 1308 due to the interaction of the connecting pin 1310 in the helical groove 1364. The pump piston 1306 translates toward the gearbox, drawing fluid from the reservoir into the pump chamber 1352. During the suction stroke, the friction between the seal and the outer diameter of the sleeve 1308 should be high enough to ensure that the sleeve 1308 does not rotate relative to the manifold 1312.

[0097] Figures 28A to 28C show the metering subsystem during valve state change after the intake stroke. The connecting pin 1310 reaches the upper end of the helical groove 1342, and the motor 1302 continues to apply torque, rotating the sleeve 1308 and piston 1306 together. The tab 1360 of the sleeve 1308 moves within the window 1364 of the manifold 1312 in the direction indicated by the arrow in Figure 28A. As the plug 1316 rotates with the sleeve 1308, the cam surface 1368 of the plug 1316 closes the sleeve limit switch 1318. The sleeve 1308 and pump piston 1306 rotate as a single unit without relative axial motion. During this rotation, the side hole 1358 of the sleeve 1308 moves between the reservoir port 1354 and the cannula port 1356.

[0098] Figures 29A and 29B show the metering subsystem in the suction rotation stop position. In this position, the side hole 1358 of the sleeve 1308 aligns with the cannula port 1356, the pump volume 1352 expands, and the reservoir port 1354 closes. The cam 1366 of the output gear 1326 engages with the rotation limit switch 1320 to signal that rotation is complete. The motor 1302 stops and reverses direction. The sleeve limit switch 1318 is open.

[0099] Figures 30A to 30C show the metering subsystem after the pump cycle is complete. The output gear cam 1366 swings slightly away from the rotary switch 1320, ready to start another cycle.

[0100] Figures 31A to 31C show another weighing system 3100a according to an exemplary embodiment of the present invention. Figure 31A shows a motor and gearbox assembly 3101 and a modified pump assembly 3100. The motor and gearbox assembly 3101 is substantially similar to the motor and gearbox assembly illustrated and described above in relation to Figures 13 to 30C.

[0101] Figure 32 is an exploded view of the pump assembly 3100. The pump assembly 3100 comprises a pump manifold 3102, a port seal 3104, a seal retainer 3106, a piston 3108 that rotates ±196° and translates ±0.038 inches (0.09652 cm) axially, a connecting pin 3110, a sleeve 3112 with a conductive pad, and a sleeve rotation limit switch 3114 having a bendable arm 3128. The sleeve 3112 with the conductive pad rotates ±56° as shown.

[0102] The pump assembly 3100 includes three bendable arms 3128 that act as rotational movement limit switches 3114. The rotational movement limit switches 3114 are described in more detail below. The rotational movement limit switches 3114 directly sense the position of the sleeve 3112, rather than sensing the position of the output gear. This allows for more precise angular alignment of the sleeve 3112 relative to the manifold 3102 and cannula report.

[0103] Figures 33A and 33B show the assembly of the piston 3108 into the sleeve 3112. In this embodiment, the inner wall 3113 of the sleeve 3112 forms the end face of the pump chamber. The function of the piston sleeve is to be designed with tolerances to minimize the gap between the end face of the piston 3108 and the surface of the inner wall 3113 of the sleeve.

[0104] Figures 34A to 34E show the assembly of the sleeve 3108 into the manifold 3102. As illustrated, the port seal 3104, seal retainer 3106, and sleeve 3112 are inserted into the manifold 3102. The small side hole 3115 of the sleeve 3112 (see Figure 34E) rotates and reciprocates between the reservoir port and the cannula port, preferably separated by 56 degrees. The sleeve 3112 is inserted into the manifold 3102 past the retaining tab 3116 (see Figure 34D) and then rotated to a position that prevents axial movement. In this embodiment, to prevent or minimize axial movement of the plug, blockage detection due to axial movement of the plug is generally not performed.

[0105] Figure 35 shows a cross-sectional view of the sleeve 3112 and manifold 3102 assembly, taken through the port seal 3104 and through the axis of the side port to the manifold 3102. The side port to the manifold 3102 includes a cannula port 3118 and a reservoir port 3120. The port seal 3104 is a face seal, which is compressed between the outer diameter of the sleeve 3112 and the concave pocket of the manifold 3102.

[0106] Figures 36A to 36C are cross-sectional views along the axis of the side port as the sleeve 3112 rotates from the reservoir port 3120 to the cannula port 3118, showing the change in valve state. In the initial position shown in Figure 36A, the sleeve side hole 3115 is open to the reservoir port 3120. In this position, the cannula port 3118 is closed. In the intermediate position shown in Figure 36B, the sleeve side hole 3115 is closed by the port seal 3104 during the transition. In the final position shown in Figure 36C, the sleeve side hole 3115 is open to the cannula port 3118. In this position, the reservoir port 3120 is closed.

[0107] Figures 37a to 37D illustrate the operation of the sleeve rotation limit switch 3114. The three-contact switch design allows the patch system to distinguish between the two rotation limits by switch input signals rather than through software tracking of the sleeve's angular orientation. The manifold 3102 preferably comprises a manifold mounting column 3122. The switch contacts 3114 are bonded to the column 3122 by adhesive, ultrasonic welding, hot piling, or any other suitable bonding method. The sleeve 3112 comprises conductive pads 3124 at the ends of the sleeve 3112. These may be printed or overmolded metal inserts, or provided by any other suitable means. The sleeve rotation limit switch 3114 comprises a plastic overmolding 3126 for the separation and mounting functions of the bends. The sleeve rotation limit switch 3114 also comprises three metal bends 3128. The manifold 3102 comprises alignment slots 3130 that receive the bends 3128. In the first position shown in Figure 37B, the side hole 3115 of the sleeve 3112 is aligned with the cannula port 3118. In this position, the conductive pad 3124 of the sleeve 3112 bridges the center contact 3128a and the right contact 3128b. In the central position shown in Figure 37C, the side hole 3115 of the sleeve 3112 is midway between ports 3118 and 3120. In this position, both sides of the switch 3114 are open. In the final position shown in Figure 37D, the side hole 3115 of the sleeve 3112 is aligned with the reservoir port 3120. In this position, the conductive pad 3124 of the sleeve 3112 bridges the center contact 3128b and the left contact 3128c.

[0108] The aforementioned pump has a modified operating sequence. The operating sequence is substantially the same as described above, except that a slight 20° backward sway is no longer required. The slight backward sway is eliminated by the aforementioned three-contact switch design, and the entire pump cycle consists of the following four segments: First, there is a pump discharge of approximately 140°, which is counterclockwise when viewed from the pump towards the gearbox. Second, there is a 56° valve state change, also counterclockwise. Third, there is a pump suction of 140°, which is clockwise. Fourth, there is a 56° valve state change, which is clockwise. The entire pump cycle requires 196° of output gear rotation in each direction.

[0109] Figures 38A and 38B are exploded views of another version of the pump assembly with the elastomer port and piston seal overmolded onto the manifold and pump piston, respectively. This version of the pump functions substantially the same as the one described above, but has fewer individual parts and is easier to assemble. Overmolding the seals directly onto the manifold and piston reduces the number of surfaces contributing to seal compression, allowing for tighter control and less variation in seal performance.

[0110] Figure 39A shows an exploded view of pump assembly 3900 with an alternative rotation limit switch design. This version of the pump assembly features a two-contact design for the sleeve rotation limit switch. This design allows the pump to swing gently backward appropriately at the end of the pump cycle, causing the contact switch 3902 to open while stationary. As shown in Figure 39B, in the first position, the side hole 3115 of the sleeve is aligned with the cannula port. In this position, the first rib 3904 of the sleeve forces the contract to close. In the middle position shown in Figure 39C, the side hole 3115 of the sleeve is in the middle of the port, and it is open because neither rib 3904 nor 3906 contacts the contact switch 3902. In the third position shown in Figure 39D, the side hole 3115 of the sleeve is aligned with the reservoir port. In this position, the second rib 3906 of the sleeve again forces the contact switch 3902 to close.

[0111] Figure 40 is an exploded view of another exemplary embodiment of the metering assembly 4000. This embodiment is substantially similar to the previously described embodiment, so the following description will focus on the differences. The metering assembly 4000 comprises a sleeve 4002 having a helical groove 4004, a plug 4006, a seal 4008, a plunger 4010, a connecting pin 4012, a manifold 4014, a port seal 4016, and a flexible interlock 4018. Figure 41 shows the metering assembly in its assembled form. The seal 4008 is preferably formed from an elastomer material and is integrally constructed. One seal 4008 is attached to the plug 4006, and the other seal 4008 is attached to the plunger 4010. The plug 4006 is preferably fixed within the sleeve 4002 by adhesive, heat sealing, or any other suitable means. The end face of the plug forms one face of the pump volume. The plunger 4010 is inserted into the sleeve 4002, and the connecting pin 4012 is press-fitted into the plunger 4010 and extends into the helical groove 4004, causing axial translational motion of the plunger 4010 when it is rotated by a motor (not shown). The end face of the plunger 4010 forms the opposing surface of the pump volume. The port seal 4016 is preferably a single molded piece of elastomer material. This embodiment reduces the number of parts and improves manufacturability. Figure 42 is a cross-sectional view of the assembled metering assembly.

[0112] Figures 43A to 43C illustrate the interaction between the interlock 4018 and the sleeve 4002. As shown in Figure 41, the interlock 4018 is attached to the manifold 4014 at either end. As shown in Figure 43A, the end face of the sleeve 4002 is provided with a retaining arm 4020 adjacent to the protrusion 4022 of the interlock 4018 when the metering assembly is in the first position (side holes are aligned with the reservoir pump). Under certain conditions, such as back pressure, the friction between the piston 4010 and the sleeve 4008 may be sufficient to rotate the sleeve before the plunger 4010 and the connecting pin 4012 reach either end of the helical groove 4004. This could result in an incomplete amount of fluid being pumped per stroke. To prevent this situation, the interlock 4018 prevents the sleeve 4002 from rotating until the torque exceeds a predetermined threshold. This ensures that the piston 4010 rotates completely within the sleeve 4008 until the connecting pin 4012 reaches the end of the helical groove 4004. Once the connecting pin hits the end of the helical groove 4004, further movement by the motor increases the torque applied to the sleeve above a threshold, bending the interlock and allowing the retaining pin 4020 to pass the ridge 4022. This is shown in Figure 43B. Once the rotation of the sleeve 4008 is complete, with the side hole facing the cannula, the retaining pin 4020 moves past the ridge 4022 of the interlock 4018. This is shown in Figure 43C.

[0113] Figure 44 is a cross-sectional view of another exemplary embodiment of the metering system 4400. The metering system 4400 comprises a modified sleeve 4402 having a surface 4404 that forms one side of the pump volume. This embodiment simplifies manufacturing by eliminating the need for a plug as in the previous embodiment.

[0114] Figure 45 shows another exemplary embodiment having a modified sleeve 4500 and a switching mechanism 4502. Figure 46 is a perspective view of the modified sleeve 4500, which includes a retaining arm 4504 similar to that of the sleeve described above to interact with an interlock (not shown). The switching mechanism 4502 includes a limit switch arm 4506 adapted to rotate in either direction away from its neutral position. The sleeve 4500 includes a switching lever (actuator arm) 4508 adapted to interact with the limit switch 4506 as the sleeve 4500 rotates. Figure 47 shows how the limit switch 4506 rotates around its axis. The switching mechanism 4502 provides an electrical signal indicating the position of the limit switch 4506. Figure 48 is a top view showing the sleeve 4500 rotated in the direction in which the limit switch 4506 rotated from its neutral position to its maximum angle (α). As the sleeve rotates further, the limit switch 4506 is released from the actuator arm 4508 and returns to its neutral position. Figure 49 is a side view oriented toward the sleeve surface, showing the same interaction between the limit switch 4506 and the actuator arm 4508. Figure 50 is a side view showing the sleeve 4500 and switching mechanism 4502 incorporated into the patch pump, along with the interlock collar 4510.

[0115] Figure 51A shows the relative angular position of the limit switch 4506 and the actuator arm 4508. Alpha (α) is the angle of the limit switch 4506. Beta (β) is the angle of the rotating sleeve and the actuator arm. Figure 51B shows the relative change d(α) / d(β) versus β. Reversal is preferably triggered at β=33°. As shown in the figure, when the actuator arm 4608 rotates, it pushes the limit switch 4506 away from the neutral position (α=0°). When the actuator arm angle β reaches approximately 30β, the actuator arm 4508 clears the limit switch 4506, and the limit switch 4506 returns to neutral (α=0°), thereby initiating the reversal of the rotary pump. When the sleeve 4508 rotates in the opposite direction, the same procedure occurs in reverse. Thus, the sleeve reciprocates back and forth.

[0116] Here, the improved plunger and pump plug components are described in relation to Figures 52–67. As described below, the improved plunger 5210 and pump bottom 5206 improve the pump by facilitating the manufacture and assembly of these components and eliminating a potential source of fluid leakage from the conventional design. The plunger 5210 is shown in multiple figures in Figures 52–58. Because the seal described below is overmolded onto the head 5210 of the plunger 5210, the plunger 5210 does not require the O-ring 4009 and is otherwise substantially the same as the plunger 4010 shown in Figure 40.

[0117] The seal 5214 is shown in multiple figures in Figures 59–62. The seal 5214 is advantageously overmolded onto the head 5212 of the plunger 5210. Thus, the sealed plunger is advantageously manufactured in a two-shot molding process. The plunger 5210 is molded from a rigid plastic material, and then the seal 5214 is molded onto the plunger 5210 as a second shot from a viscoelastic elastomer. Combining the plunger 5210 and the seal 5214 makes assembly into the entire pump easier and reduces the potential for leakage present in the O-ring design.

[0118] Pump stoppers or plugs 5206 are shown in Figures 63–67. Stoppers 5206 substantially correspond to plugs 4006 in Figure 40, except that a seal 5214 is overmolded onto the head 5208 of stoppers 5206 instead of an O-ring (the same or substantially similar sealing component can be used for both plungers 5210 and stoppers 5206). Similar to plungers 5210 described above, stoppers 5206 and seals 5214 are preferably manufactured in a two-shot molding process. Stoppers 5206 are molded from a rigid plastic material, and seals 5214 are molded onto stoppers 5206 as a second shot from a viscoelastic elastomer.

[0119] Figure 68 shows an exploded view of a weighing assembly 4000, which includes an improved plunger 5210, a stopper 5206, and a seal 5214. As will be understood by those skilled in the art, in the conventional design, the plug 4006 is optional and can be replaced by a wall 4404 shown in Figure 44, thereby the stopper 5206 is optional and interchangeable with a similar wall.

[0120] A method 6900 for manufacturing and assembling a pump according to an exemplary embodiment of the present invention utilizing the overmolded parts described above will be described with reference to Figure 69. First, in step 6902, a plunger is molded from rigid plastic. Next, in step 6904, a seal is overmolded onto the head of the plunger. The seal is molded from a viscoelastic elastomer and is sized to fit into and seal the pump chamber. If necessary, a pump stopper is molded from rigid plastic in step 6906, and a seal is overmolded onto the head of the pump stopper in step 6908. In step 6910, the plunger and pump stopper are inserted into the pump chamber of the pump.

[0121] Further embodiments of the present invention are shown in Figures 70A–70L. For it to function as intended, the sleeve and plunger must operate in the correct sequence. That is, since the output gear is coupled to the plunger, the output gear is intended to rotate the plunger first, and the coupling pin moves within the helical slot of the sleeve, causing the plunger to move forward or backward. Then, after the coupling pin reaches the end of the slot (either end depending on the direction of rotation) and rotates further, the plunger and sleeve rotate together, changing the orientation of the sleeve relative to the manifold. However, as mentioned above, in practice, friction or other forces can cause the movement to occur out of order. If the force between the plunger and sleeve is too large to be relieved, the plunger and sleeve may rotate together first before the plunger moves relative to the sleeve. Figures 40–43C show a flexible interlock that initially resists the rotation of the sleeve until the plunger has fully moved forward or backward. Figures 70A–70L show an alternative embodiment of the pump described herein, in which a reciprocating shuttle may be included in the pump mechanism to replace the flexible interlock. A reciprocating shuttle, independent of the flexibility or other properties of the interlocking portion, advantageously allows the pump mechanism to sequence more reliably and accurately in a deterministic manner. An exemplary reciprocating shuttle is described here.

[0122] Figures 70A–70L schematically show the sleeve 7001, output gear 7002, coupling pin 7003, helical slot 7004, and reciprocating shuttle 7005. To illustrate the shuttle's movement, "bullseyes" or "dots" on the shuttle 7005 indicate movement out of the drawing surface along an axis extending perpendicular to the drawing surface, while "crosses" or "x" on the shuttle indicate movement inward from the drawing surface. As described above, the movement of the coupling pin 7003 in the helical slot 7004 corresponds to the axial movement of the plunger in the sleeve, which increases or decreases the volume of the pump chamber.

[0123] In the illustrated embodiment, when the shuttle 7005 retracts into the drawing surface, it does not obstruct the rotation of the sleeve 7001, and when the shuttle 7005 advances out of the drawing surface, it prevents the rotation of the sleeve 7001 by obstructing the movement of the stopper 7006. Figures 7C, 7D, 7I, and 7J show portions of the sequence in which the shuttle 7005 interferes with the rotation of the sleeve 7001. However, the forward / retracted positions can be reversed as needed, and the embodiment can still function as intended, as long as the shuttle blocks or allows the rotation of the sleeve at the appropriate moment in the pumping sequence.

[0124] The pumping sequence involving the movement of the shuttle 7005 is described in detail here. Figure 70A shows the initial positions in the pumping sequence. The sleeve 7001 is in a first position, for example, with the input port aligned with the reservoir port of the manifold. The plunger and pin 7003 are in their initial positions by the pump reservoir in their empty configuration. The output gear 7002 is in its initial position to begin the first part of its reciprocating rotation. The shuttle 7005 retracts completely into the surface of the drawing so as not to interfere with the movement of the stopper 7006.

[0125] Figure 70B shows the start of rotation of the output gear 7002. Preferably, during this portion, the coupling pin 7003 moves into the slot 7004, retracting the plunger and increasing the volume of the pump chamber. However, the sleeve 7001 may tend to rotate with the output gear due to friction or other forces. Due to the interaction of a cam or other similar structure, which will be described later, at this stage of the sequence, the shuttle 7005 begins to move toward exiting the drawing surface. As shown in Figure 70C, the cam or other interaction between the shuttle and the output gear causes the shuttle to move fully forward, preventing the stopper 7006 from rotating any further and allowing the output gear and coupling pin 7003 to rotate. As a result, the output gear and coupling pin rotate until the coupling pin reaches the end of the helical slot 7004. Meanwhile, the sleeve 7001 and its stopper 7006 remain stationary, as shown in 70D. As shown in Figure 70E, at this stage, the cam (or another suitable interaction between the output gear and the shuttle) causes the shuttle 7005 to retract into the drawing surface. As a result, the sleeve 7001 and the retaining pin 7006 become rotatable. Figure 70F shows how the output gear 7002, coupling pin 7003, and sleeve 7001 all rotate together, moving the sleeve so that its port faces from the input position to the output position relative to the manifold. Figure 70G shows the pump mechanism at the end of the first half of the reciprocating motion. The sleeve 7001 has rotated completely to the output position relative to the manifold, and the shuttle 7005 remains retracted.

[0126] Figure 70H shows the start of the reciprocating motion returning to the initial position. The output gear 7002, coupling pin 7003, and possibly sleeve 7001 begin to rotate counterclockwise. Due to the interaction of the cam (or another suitable interaction between the output gear and the shuttle), the shuttle 7005 begins to move again in the direction of exiting the surface service of the drawing. Figure 70I shows part of the sequence in which the shuttle 7005 moves forward completely again, preventing the sleeve 7001 from rotating, and the output gear 7002 and coupling pin 7003 rotate counterclockwise. Figure 70J shows part of the sequence in which the coupling pin 7003 rotates completely within the helical slot 7004, thereby reducing the size of the pump chamber and discharging fluid through the output port of the manifold. Figure 70K shows that as the output gear 7002 continues to rotate clockwise, the cam (or another suitable interaction between the output gears in the shuttle) pushes the shuttle 7005 back into the surface of the drawing. Figure 70L shows the shuttle 7005 fully retracting, with the output gear 7002, coupling pin 7003, and sleeve 7001 all rotating together to return to the initial position shown in Figure 70A. This is the complete pumping sequence, which can be repeated as needed to deliver the chemical from the reservoir through the pumping chamber to the output port.

[0127] Figure 71 shows an exploded view of the assembly of the output gear 7002 and the shuttle 7005, which reciprocates the shuttle in appropriate time relative to the rest of the pump assembly, moving it forward and backward. The shuttle 7005 includes a shuttle pin 7009. Although the shuttle pin 7009 is illustrated, other coupling or interconnecting structures will of course be well understood by those skilled in the art. The output gear 7002 includes a cam structure 7007, which further includes a shuttle cam slot 7008. The shuttle pin 7009 is received within the shuttle cam slot 7008, and therefore, as the output gear 7002 rotates, the shuttle pin 7009 is forced to move within the shuttle cam slot 7008, so that the shuttle 7005 moves forward and backward in the direction indicated by the arrows. Figures 72A-72C further illustrate this movement. It should be noted that structures to restrict the movement of the shuttle 7005 in directions other than along the arrows shown in Figure 71 must be included, but are not shown here for the sake of simplification. In Figure 72A, the output gear 7002 is ready to begin rotating in one direction, and the shuttle 7005 is in its fully retracted position. The shuttle pin 7009 is at the far end of the shuttle cam slot 7008. As shown in Figure 72B, the output gear 7002 is in the middle of rotating in this direction, and the shuttle 7005 has advanced to its fully forward position due to the interaction between the shuttle pin 7009 and the shuttle cam slot 7008. Figure 72C shows the end of the first rotation of the output gear 7002. At this position, the shuttle 7005 is again fully retracted, and the shuttle pin 7009 is at the far end on the opposite side of the shuttle cam slot 7008. As will be understood by those skilled in the art, this example illustrates an example of a mechanical structure for achieving regular and deterministic forward and backward movement of the shuttle in order to block or allow the rotation of the sleeve as described above. Any other suitable mechanical configuration that provides precise timing of the forward and backward movement of the shuttle and the rotation of the sleeve is considered to be within the scope of the art.

[0128] Although a few exemplary embodiments of the present invention have been described in detail, those skilled in the art will readily understand that many modifications are possible in the exemplary embodiments and various combinations of the exemplary embodiments without significantly departing from the novel teachings and advantages of the present invention. Therefore, all such modifications are within the scope of the present invention.

Claims

1. A manifold equipped with a fluid reservoir, a reservoir port communicating with the fluid, and a cannula port communicating with the fluid, A sleeve having side holes, configured to rotate axially within the manifold between a first orientation in which the side holes are aligned with the reservoir port and a second orientation in which the side holes are aligned with the cannula port, and further comprising a helical groove having a first end and a second end, A plunger comprising an overmolded seal formed on a plunger head adapted to rotate and axially translate within the sleeve, wherein the axial translation of the plunger within the sleeve changes the pump volume, the pump volume is in fluid communication with the side hole of the sleeve, and the plunger further comprises a connecting member configured to move between the first and second ends of the helical groove within the helical groove, causing the plunger to axially translate within the sleeve when the plunger rotates, A motor configured to rotate the plunger in a first direction, It has a cam with a shuttle cam slot, and an output gear that transmits the motor's movement to the plunger, A shuttle that is linked to the aforementioned shuttle cam slot, Equipped with, The aforementioned sleeve is equipped with a stopper, The shuttle is positioned such that it restricts the return stopper and the rotation of the sleeve when the shuttle is in the forward position. The shuttle is arranged such that when the shuttle is retracted and in the retracted position, the stopper and the sleeve are allowed to rotate. When the rotation of the sleeve is restricted, the sleeve is configured to be in the first orientation and the plunger is configured to rotate in the first direction, thereby increasing the pump volume. A metering pump characterized in that, when the rotation of the sleeve is permitted and the connecting member reaches the first end of the helical groove, the sleeve and the plunger rotate together, and the sleeve is configured to move in the second orientation.

2. The metering pump according to claim 1, characterized in that the shuttle comprises a pin that engages with the shuttle cam slot.

3. The metering pump according to claim 1, characterized in that the shuttle cam slot is configured to advance the shuttle in order to prevent the sleeve from rotating until the plunger has moved completely while the output gear is rotating.

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