ROTARY DOSING JOINT PUMP

Abstract

A rotary pump is provided for a fluid metering system. The rotary pump moves reciprocally and is reversed by a signal from a limit switch that is diverted by an actuator arm on a rotating sleeve of the pump system. The sleeve receives a gasket that forms a seal between the sleeve and the housing. The gasket has an opening surrounding a lateral port in the sleeve to allow fluid to pass through the lateral port between a volume of the pump and an inlet or outlet port of the housing.

Description

ROTARY DOSING JOINT PUMP Related requests This application relates to U.S. patent application no. 16 / 521,685, filed July 25, 2019, which is a continuation in part of U.S. patent application no. 15 / 300,695, filed September 29, 2016, which was the U.S. national phase of international application no. PCT / US2015 / 024517, filed April 6, 2015, which claims priority to U.S. provisional application no. 61 / 976,361, filed April 7, 2014. Each of these applications is incorporated herein by reference. Field of invention The present invention relates in general to dosing systems for use in portable drug infusion patches. Background of the invention Diabetes is a group of diseases characterized by high blood glucose levels resulting from defects in insulin production, insulin action, or both. Diabetes can lead to serious health complications and premature death, but there are well-known products available for people with diabetes to help manage the disease and reduce the risk of complications. Treatment options for people with diabetes include specialized diets, oral medications, and / or insulin therapy. The primary goal of diabetes treatment is to control the patient's blood glucose (sugar) level to increase the chances of a life without complications. However, achieving good diabetes control while balancing other life demands and circumstances is not always easy. Currently, there are two main modes of daily insulin therapy for treating type 1 diabetes. The first mode includes insulin syringes and pens, which require a needle prick for each injection, typically three to four times a day. These devices are simple to use and relatively inexpensive. Another widely adopted and effective treatment method for managing diabetes is the use of an insulin pump. Insulin pumps can help users maintain their blood glucose levels within target ranges based on their individual needs by delivering a continuous infusion of insulin at varying rates to more closely mimic the pancreas's function. By using an insulin pump, users can tailor their insulin therapy to their lifestyles, rather than matching their lifestyles to how an insulin injection works for them. However, conventional insulin pumps suffer from several drawbacks. u L / en / eznz / q / YiAi For example, the screw-driven and piston-type dosing systems commonly used in insulin pumps are often cumbersome for users, requiring a large height and footprint. Conventional insulin pumps also typically require a large number of components and moving parts, thus increasing the risk of mechanical failure. Conventional insulin pumps also often have a tolerance cycle that is too long for accurate dosing, as it depends on too many factors, which are sometimes difficult to determine. This can result in a loss of dosing accuracy. Conventional insulin pumps also often have an overly complex fluid path. This can result in complicated or inadequate priming and air removal. Conventional insulin pumps also typically require high-precision actuators, thus increasing the cost of conventional patch pumps. Some insulin pumps also run the risk of creating direct fluid pathways between a reservoir and an insulin patch cannula. This can result in an overdose for a user. Conventional insulin pumps also often require complex detection systems. This can lead to increased costs and reduced accuracy and reliability. Conventional insulin pumps also often have valves that tend to leak at high system backpressures. This can result in reduced accuracy and reliability. Conventional insulin pumps also typically require large working volumes and large system volumes exposed to potentially high backpressure. This can result in reduced accuracy and reliability. Conventional insulin patches also often have low-efficiency motors that require large batteries, thus reducing the size of the insulin patch. Therefore, there is a need for a dosing system with reduced height and footprint, compared to conventional screw and piston dosing systems, to increase user comfort. There is also a need for a dosing system with a reduced number of components and moving parts, compared to conventional insulin pumps, to increase the mechanical safety of insulin patches. There is also a need for a dosing system with a short tolerance loop for dose accuracy, which depends on several factors, compared to conventional dosing pumps, thus increasing dose accuracy. There is also a need for a dosing system with a simple fluid path, compared to conventional dosing systems, thus simplifying priming and air removal. There is also a need for a dosing system that uses a low-precision actuator, compared to conventional dosing systems, thereby reducing the cost of insulin patches. There is also a need for a dosing system without direct fluid flow between the reservoir and the cannula, compared to conventional dosing systems, thus better protecting a user against overdose. There is also a need for a dosing system with simple detection schemes, compared to conventional dosing systems, thereby reducing the cost and increasing the accuracy and reliability of insulin patches. There is also a need for a dosing system with valves that are robust against leakage at high system backpressures, compared to conventional dosing systems, thereby increasing the accuracy and reliability of insulin patches. There is also a need for a dosing system with a small working volume and a low system volume exposed to potentially high back pressure, compared to conventional dosing systems, thereby increasing the accuracy and reliability of insulin patches. There is also a need for a dosing system that requires a high-efficiency motor with small batteries, compared to conventional dosing systems, thus reducing the size of insulin patches. BRIEF DESCRIPTION OF THE INVENTION One aspect of the illustrative embodiments of the present invention is to substantially address the above and other concerns, and to provide a small and reliable dosing system. One aspect of the illustrative embodiments is to reduce complexity by eliminating the need for an interlocking mechanism. Another aspect of the illustrative embodiment is to increase insulin compatibility by reducing shear stress between surfaces where insulin can become trapped. These and other aspects of this disclosure are realized by providing a rotary metering pump comprising a sleeve having a side orifice. The sleeve receives a seal having a first seal opening disposed around the side orifice. The sleeve and seal are adapted to rotate axially within a housing having an inlet port connected to a fluid reservoir and an outlet port connected to a delivery cannula. The sleeve further comprises a helical groove having a first end and a second end. The pump also includes a plunger received within the sleeve and adapted to rotate and translate axially within the sleeve, wherein the axial translation of the plunger within the sleeve changes the pump volume, the pump volume being in fluid communication with the side orifice of the sleeve.The plunger further comprises a coupling element adapted to move within the helical groove and between the first and second ends of the groove, causing the plunger to translate axially within the sleeve as the plunger rotates. A motor is adapted to rotate the plunger in a first direction, thereby increasing the pump volume when the sleeve is in the first orientation, and to rotate the sleeve and plunger together when the coupling element reaches the first end of the helical groove, so that the sleeve moves to the second orientation. An output gear transmits the motor's motion to the plunger. The gasket forms a seal between the sleeve and the housing, allowing fluid to pass through the first opening in the gasket between the pump volume and either the inlet or outlet port. BRIEF DESCRIPTION OF THE DRAWINGS The various objects, advantages, and novel features of the illustrative embodiments of the present invention will be more readily appreciated from the following detailed description when read in conjunction with the accompanying drawings, in which: Figure 1 shows a diagram of an architecture of an illustrative embodiment of a patch pump according to the present invention; Figure 2 shows the arrangement of the fluid system and dosing components of an illustrative embodiment of a patch pump according to the present invention; Figure 3 shows an exploded schematic view of a dosing subsystem of an illustrative embodiment of a patch pump according to the present invention; Figure 4 shows the arrangement of a dosing subsystem of an illustrative embodiment of a patch pump according to the present invention; Figure 5 shows a schematic cross-sectional view of a dosing subsystem of an illustrative embodiment of a patch pump according to the present invention; Figures 6A and 6B show multiple views of a dosing subsystem of an illustrative embodiment of a patch pump according to the present invention, in an initial position; L? L / en / eznz / q / YiAi Figures 7A and 7B show multiple views of a dosing subsystem of an illustrative embodiment of a patch pump according to the present invention, during an intake stroke; Figures 8A, 8B and 8C show multiple views of a dosing subsystem of an illustrative embodiment of a patch pump according to the present invention, during a valve state change after an intake stroke; Figures 9A and 9B show multiple views of a dosing subsystem of an illustrative embodiment of a patch pump according to the present invention, in an intake stroke stop position; Figures 10A and 10B show multiple views of a dosing subsystem of an illustrative embodiment of a patch pump according to the present invention, during a discharge stroke; Figures 11A, 11B, and 11C show multiple views of a dosing subsystem of an illustrative embodiment of a patch pump according to the present invention, during a valve state change after a discharge stroke; Figures 12A and 12B show multiple views of a dosing subsystem of an illustrative embodiment of a patch pump according to the present invention, after a pump cycle is completed; Figure 13 shows an exploded view of a dosing subsystem of an illustrative embodiment of a patch pump according to the present invention; Figure 14 shows an exploded schematic view of a pump assembly of an illustrative embodiment of a metering pump according to the present invention; Figure 15 shows an exploded schematic view of a motor and gearbox assembly of an illustrative embodiment of a metering pump according to the present invention; Figures 16A, 16B, 16C and 16D show multiple schematic views illustrating a method of mounting a piston in a sleeve according to the present invention; Figures 17A, 17B and 17C show multiple schematic views illustrating a method of mounting a plug in a sleeve according to the present invention; Figures 18A, 18B, 18C and 18D show multiple schematic views illustrating a method of mounting a sleeve on a manifold according to the present invention; Figure 19 is a schematic cross-sectional view of a pump assembly of an illustrative embodiment of a patch pump according to the present invention; Figures 20A, 20B, 20C, 20D and 20E show multiple schematic cross-sectional views illustrating a valve state-changing method according to the present invention; Figures 21A, 21B, and 21C show multiple views of limit switches for pump and sleeve rotation in a dosing subsystem of an illustrative embodiment of a patch pump according to the present invention; Figures 22A, 22B and 22C show multiple schematic cross-sectional views illustrating a method of mounting a pump in a gearbox according to the present invention; Figures 23A, 23B and 23C show multiple views of a dosing subsystem of an illustrative embodiment of a patch pump according to the present invention, in an initial position; Figures 24A and 24B show multiple views of a dosing subsystem of an illustrative embodiment of a patch pump according to the present invention, during a discharge stroke; Figures 25A, 25B and 25C show multiple views of a dosing subsystem of an illustrative embodiment of a patch pump according to the present invention, during a valve state change after a discharge stroke; Figures 26A and 26B show multiple views of a dosing subsystem of an illustrative embodiment of a patch pump according to the present invention, in a discharge rotation stop position; Figures 27A and 27B show multiple views of a dosing subsystem of an illustrative embodiment of a patch pump according to the present invention, during an intake stroke; Figures 28A, 28B and 28C show multiple views of a dosing subsystem of an illustrative embodiment of a patch pump according to the present invention, during a valve state change after an intake stroke; Figures 29A and 29B show multiple views of a dosing subsystem of an illustrative embodiment of a patch pump according to the present invention, in an intake rotation stop position; Figures 30A, 30B and 30C show multiple views of a dosing subsystem of an illustrative embodiment of a patch pump according to the present invention, after a pump cycle is completed; Figures 31A, 31B, and 31C show multiple views of the motor and gearbox assembly, as well as a modified pump assembly, from an illustrative embodiment of a dosing assembly according to the present invention; Figure 32 shows an exploded view of a pump assembly of one embodiment L? L / en / eznz / q / YiAi illustrative of a dosing assembly according to the present invention; Figures 33A and 33B show a piston-in-sleeve assembly of an illustrative embodiment of a patch pump according to the present invention; Figures 34A, 34B, 34C, 34D and 34E show a sleeve assembly in a manifold of an illustrative embodiment of a patch pump according to the present invention; Figure 35 shows a cross-section of a sleeve and manifold assembly of an illustrative embodiment of a patch pump according to the present invention; Figures 36A, 36B and 36C show multiple cross-sections of a valve state change of an illustrative embodiment of a patch pump according to the present invention taken while rotating the sleeve; Figures 37A, 37B, 37C and 37D show a sleeve rotation limit switch of an illustrative embodiment of a patch pump according to the present invention; Figures 38A and 38B show an exploded view of a pump assembly with elastomeric port and piston seals overmolded in a manifold and pump piston respectively of an illustrative embodiment of a patch pump according to the present invention; Figures 39A, 39B, 39C and 39D show an exploded view of a pump assembly with an alternative rotation limit switch design of an illustrative embodiment of a patch pump according to the present invention; Figure 40 shows an exploded view of an illustrative embodiment of a dosing assembly according to the present invention; Figure 41 shows an assembled view of the dosing assembly of Figure 40; Figure 42 shows a cross-sectional view of the dosing assembly of Figure 40; Figures 43A, 43B and 43C show the interaction of an interlock with a sleeve of the dosing assembly of Figure 40 according to an illustrative embodiment of the present invention; Figure 44 shows a cross-sectional view of another illustrative embodiment of a dosing assembly according to the present invention; Figure 45 is an symmetrical view of a limit switch and a useful actuating arm in an alternative exemplary embodiment of the present invention; Figure 46 is an symmetrical view of the limit switch and rotating sleeve according to the embodiment of Figure 45; Figure 47 is a top view of the limit switch of Figure 45; Figure 48 is a top view of the injector and actuator arm of Figure 45; i / 1 / ρη / ρζηζ / ζι / γίΛΐ Figure 49 is an end view of the rotating sleeve of Figure 46.; Figure 50 is an elevation view of the cross-section of the limit switch and actuating arm of Figure 45; Figures 51A and 51B are graphics illustrating the relative displacement of the limit switch and the rotating sleeve according to an exemplary embodiment of the invention; Figures 52 to 58 illustrate different perspective views of an improved piston for a pump according to another embodiment of the invention; Figures 59 to 62 illustrate different perspective views of an overmolded seal for the improved plunger of Figures 52 to 58; Figures 62 to 67 illustrate different perspective views of an improved pump stopper; Figure 68 is a detailed view of the pump system utilizing the improved plunger, plug, and overmolded seals of an exemplary embodiment of the invention; Figure 69 is a flow diagram of a method for manufacturing a pump according to an exemplary embodiment of the invention; Figures 70A, 70B, 70C, 70D, 70E, 70F, 70G, 70H, 70I, 70J, 70K and 70L illustrate end views of a shuttle interlock pump according to an exemplary embodiment of the invention; Figure 71 is an exploded view of the shuttle interlock pump components of Figures 70A-70L; Figures 72A, 72B and 72C illustrate the operation of the shuttle interlock pump of Figures 70A-70L and 71; Figure 73 is an exploded view of another embodiment of the invention; Figure 74 is a perspective view of the realization illustrated in Figure 73; Figure 75 is a cross-sectional view of the embodiment of Figure 73; Figure 76 is a perspective view of the realization of Figure 73; Figure 77 is a perspective view of the realization of Figure 73; Figures 78 and 79 are cross-sectional views of the embodiment of Figure 73; Figure 80 illustrates a gasket for use in the pump illustrated in Figure 73; Figure 81 illustrates an alternative gasket for use on the pump illustrated in Figure 73; and Figure 82 illustrates the realization of Figure 73 using the alternative joint of Figure 81. Throughout all drawings, similar reference numbers should be understood as similar elements, features, and structures. i / 1 / pn / Pznz / zi / YiAi DETAILED DESCRIPTION OF THE ILLUSTRATIVE PRODUCTIONS As those skilled in the art will appreciate, there are numerous ways to implement the examples, improvements, and arrangements of a dosing system according to embodiments of the present invention disclosed herein. Although reference will be made to the illustrative embodiments depicted in the drawings and in the following descriptions, the embodiments disclosed herein are not intended to be exhaustive of the various alternative designs and embodiments encompassed by the described invention, and those skilled in the art will readily appreciate that various modifications and combinations can be made without departing from the invention. Although several persons, including, but not limited to, a patient or a health professional, may operate or use illustrative embodiments of the present invention, for brevity, an operator or user shall be referred to hereinafter as user. Although various fluids may be used in illustrative embodiments of the present invention, for the sake of brevity, the liquid in an injection device will hereafter be referred to as the fluid. Illustrative embodiments according to the present invention are shown in Figures 1-30. In one illustrative embodiment according to the present invention, a dosing system is provided for use in a portable insulin infusion patch. For example, in illustrative embodiments of the present invention, the dosing system is part of a larger fluid subsystem that includes a flexible reservoir for storing insulin and a cannula assembly for delivering insulin into the subcutaneous tissue. The dosing system draws a small dose of fluid from the reservoir and then pushes it through the cannula line toward the patient. The fluid dose is small relative to the volume of the reservoir, such that many pump strokes are required to completely empty the reservoir. Figure 1 shows a diagram of a patch pump 100 architecture according to an exemplary embodiment of the present invention. The patch pump 100 includes a fluid subsystem 120, an electronic subsystem 140, and an energy storage subsystem 160. The fluid subsystem 120 includes a filling port 122 in fluid communication with a reservoir 124. The reservoir 124 is adapted to receive fluid from a syringe, through the filling port. The fluid subsystem 120 further includes a volume sensor 126 mechanically coupled to the reservoir 124. The volume sensor 126 is adapted to detect or determine the volume of fluid in the reservoir. The fluid subsystem 120 further includes a dosing 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 the reservoir 124 of the fluid subsystem 120, and is actuated by the pump and valve actuator 134. The fluid subsystem 120 further includes a cannula mechanism having a deployment actuator 128 mechanically coupled to a cannula 129. The deployment actuator 128 is adapted for inserting the cannula 129 into a user. The cannula 129 is in fluid communication with the integrated pump and valve system 132 of the dosing subsystem 130. The fluid subsystem 120 further includes an occlusion sensor 136 mechanically coupled to a fluid path between the cannula 129 and the integrated pump and valve system 132. The occlusion sensor 136 is adapted to detect or determine an occlusion in the path between the cannula 129 and the integrated pump and valve system 132. The electronic subsystem 140 includes volume sensing electronics 142 electrically coupled to the volume sensor 126 of the fluid subsystem 120, a pump and valve controller 144 electrically coupled to the pump and valve actuator 134 of the dosing subsystem 130, occlusion sensing electronics 146 electrically coupled to the occlusion sensor 136 of the fluid subsystem 120, and optional deployment electronics 148 electrically coupled to the cannula 129 of the fluid subsystem. The electronic subsystem 140 further includes a microcontroller 149 electrically coupled to the volume sensing electronics 142, the pump and valve controller 144, the occlusion sensing electronics 146, and the deployment electronics 148. The energy storage subsystem 160 includes batteries 162 or any other known source of electrical energy. The batteries 162 can be adapted to power any electronic element or component of the patch pump 100. Figure 2 shows the arrangement of the fluid system and dosing components of a patch pump 200 according to an exemplary embodiment of the present invention. The patch pump 200 includes a dosing subsystem 230, control electronics 240, batteries 260, a reservoir 222, a filling port 224, and a cannula mechanism 226. The elements of the patch pump 200 are substantially similar and interact in a substantially similar manner to the elements of the illustrative patch pump 100, which are referenced by similar reference numbers. Figure 3 is an exploded view of a dosing subsystem 300 of a patch pump according to an exemplary embodiment of the present invention. The dosing subsystem 300 includes a DC gear motor 302 mechanically coupled to a pump piston 304 disposed within a pump housing 306. The pump piston 304 is mechanically coupled to a pump housing 308 by means of a coupling pin 310. The dosing subsystem 300 further includes a pump seal 312 between the pump piston 304 and the pump housing 308. The dosing subsystem 300 further includes port seals 314 in a seal carriage 316 disposed within a valve housing 318. In an exemplary embodiment of the present invention, the DC gearmotor output shaft 320 can rotate 360° in either direction. The pump piston 304 can rotate 360° in either direction and can be translated approximately 0.050 inches (1.27 mm). The pump housing 308 can rotate 180° in either direction. The pump housing 306, port seals 314, seal carriage 316, and valve housing 318 are preferably stationary. The dosing subsystem 300 includes a positive displacement pump with an integrated flow control valve and mechanical actuator and drive system. The pump includes a piston 304 and a rotationally actuated selector valve. The dosing system draws a precise volume of insulin from a flexible reservoir into a pump volume 320 formed between the piston 304 and the pump housing 308 (see Figure 5), and then expels this volume of insulin through a cannula into the patient's subcutaneous tissue, delivering insulin in small, discrete doses. The pump stroke creates positive and negative pressure gradients within the fluid path to induce flow. The stroke and the internal diameter of the pump volume determine the nominal size and dose accuracy.The fluid control valve actively moves between the reservoir and the cannula fluid ports at each end of the pump stroke to alternately block and open the ports to ensure that fluid flow is unidirectional (from the reservoir to the patient) and that there is no possibility of free flow between the reservoir and the patient. Figure 4 is an overall view of the dosing system 300 according to an exemplary embodiment of the present invention. Also illustrated are a piston-motor coupling 322, a piston for coupling to the pump housing 324, a reservoir port 326, and a cannula port 328. Figure 5 is a cross-sectional view of the dosing system 300 according to an exemplary embodiment of the present invention. As illustrated, a pump volume 320 is formed between the piston and the pump housing 308. The pump housing includes a side port 330 that alternates in orientation between the reservoir port 326 and the cannula port 328 as the motor 302 alternates the pump, as will be described in more detail below. u L / en / eznz / q / YiAi In operation, an illustrative cycle of a dosing system according to the present invention includes four stages: a 180° (counterclockwise) pump inlet (viewed from the pump towards the motor); a 180° (counterclockwise) valve state change; a 180° (clockwise) pump outlet; and a 180° (clockwise) valve state change. A complete cycle requires a full rotation (360°) in each direction. Figure 6A is an isometric view, and Figure 6B is a cross-sectional view of the dosing subsystem 300 in an initial position. In the initial position, the pump piston 302 is fully extended, the pump housing blocks the flow path of the cannula port at the cannula port 328, and the reservoir port 326 is open to the side port 330 of the pump housing 308, and a rotation limit sensor 332 is engaged. The pump housing 308 includes a helical groove 334 that receives the coupling pin 310. The piston 304 is in sliding coupling with the pump housing 308 such that when the piston 304 rotates within the pump housing 308 (by the rotational force of the motor 302), the coupling pin 310 slides along the helical groove 334 to force the piston 304 to move axially with reference to the pump housing 308.In this embodiment, the helical groove 334 is formed in the pump housing 308 and provides 180° of rotation for the coupling pin 310. Figure 7A is an isometric view, and Figure 7B is a cross-sectional view of the dosing subsystem 300 during an intake stroke. The DC motor 302 rotates the pump piston 304, which is driven along the helical groove 334 (rotation and translation) of the pump housing 308 via the coupling pin 310. The pump piston 304 is translated toward the DC motor 302, drawing fluid into the expanding volume of pump 320. During the intake stroke, the friction between the seals and the outer diameter of the pump housing 308 is preferably high enough to ensure that the pump housing 308 does not rotate. The pump housing 308 is stationary, while the volume of pump 320 expands. The cannula port 328 is blocked, while the reservoir port 326 is open to fluid flowing into the expanding pump volume 320.There is a sliding coupling between the 302 motor and the 304 pump piston. Figure 8A is an overall view, Figure 8B is a detailed view, and Figure 8C is a cross-sectional view of the patch pump during a valve state change after an intake stroke. Torque is transmitted from the motor drive shaft 302 to the pump piston 304 and then to the pump housing 308 via the coupling pin 310. Once the coupling pin 310 rotates to the end of the helical groove 334, further rotation of the motor 302 causes the coupling pin 310 to rotate the pump housing 308 and the pump piston 304 together as a unit with no relative axial translation. The side port 330 in 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 keeps the fluid in the pump volume 320.The side port of the pump housing 330 becomes misaligned with the reservoir port 326 and aligns with the cannula port 328 during the next 180° rotation of the motor 302. In between, both the cannula port 328 and the reservoir port 326 are locked. The coupling pin 310 is located at the end of the helical groove 334 and transmits torque to the pump housing 308. The coupling pin 310 locks the pump piston 304 and the pump housing 308 together to prevent relative axial movement between the two components. The pump piston 304 and the pump housing 308 therefore rotate as a unit and do not translate relative to each other. The pump housing 308 rotates while the pump volume 320 is fixed and the pump piston 304 rotates. Seals 314, seal carriage, and valve housing 318 are preferably stationary. Figure 9A is an overall view, and Figure 9B is a cross-sectional view of the dosing subsystem in a stopped position of the inlet stroke, ready to infuse. As illustrated, 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 is blocked. The rotation limit sensor 332 is engaged by a feature on the rotating pump housing 308. The motor 302, pump piston 304, and pump housing 308 are stationary. Figure 10A is an overall view, and Figure 10B is a cross-sectional view of the dosing subsystem 300 during a discharge stroke. At the end of the inlet stroke, the pump housing 308 engages with the limit switch 332, causing the DC motor 302 to reverse direction. Consequently, the motor 302 rotates the piston 304 and drives the coupling pin 310 through the helical groove 334 in the pump housing 308, causing the piston 304 to move axially. The pump piston 304 moves axially away from the DC motor 302, pushing fluid from the pump volume 320 and out of the cannula port 328 into the cannula. During the discharge stroke, the friction between the 314 seals and the outer diameter of the 308 pump housing is preferably high enough to ensure that the 308 pump housing does not rotate.The cannula port 328 is open to the fluid exiting the collapsed pump volume 320. The reservoir port 326 is blocked. The pump housing 308 is stationary while the pump volume 320 collapses and the pump piston 304 rotates and translates in a helical motion. The motor is slidably connected to the piston 304 to accommodate the piston's translational motion as it rotates in the helical groove 334. Figure 11A is an overview view, Figure 11B is a detailed view, and Figure 11C is a cross-sectional view of the dosing subsystem 300 during a valve state change after a discharge stroke. Torque is transmitted from the motor drive shaft 302 to the pump piston 304 and then to the pump housing 308 via the coupling pin 310. The pump housing 308 and the pump piston 304 rotate as a unit with no relative axial movement. The side port 330 in the pump housing 308 rotates between the reservoir port 326 and the cannula port 328, both of which are locked during rotation. The surface tension of the side port 330 of the pump housing 308 keeps the fluid in the pump volume 320. The coupling pin 310 locks the pump piston 304 and the pump housing 308 together to prevent relative axial movement between the two components.Therefore, the piston of pump 304 and the pump housing 308 rotate as a unit and do not translate relative to each other. The pump housing 308 rotates while the pump volume 320 is fixed. The seals 314, seal carriage, and valve housing 318 are preferably stationary. Figure 12A is an overall view, and Figure 12B is a cross-sectional view of the dosing subsystem 300 after completing a pumping cycle. The pump mechanism (piston 304) is fully extended, completing the pump cycle. The rotation limit sensor 332 engages to reverse the motor 302 and restart the pump cycle. The cannula port 328 is blocked, while the tank port 326 is open to allow flow from the tank. In the preceding embodiment, the pump piston rotates and translates, the pump housing rotates, and the valve housing is stationary. However, it should be appreciated that in other embodiments, the system can be configured so that the pump piston rotates, the pump housing rotates and translates, and the valve housing translates, or any other combination of movements that causes the pump volume to increase and decrease, and a port communicating with the pump volume to move from alignment with the reservoir port to alignment with the cannula port. In the previous example, the pump stroke and valve state change are configured with a 180° rotary drive from the motor. However, it should be noted that any suitable angle can be selected for the pump cycle segments. In the preceding embodiment, there is an atmospheric rupture between the cannula and the reservoir ports during the valve's state change. However, it should be noted that in other embodiments, the seals can be configured, or additional seals can be added, to eliminate the atmospheric rupture and seal the pump and valve system during the state change. In the preceding embodiment, a DC geared motor is used to drive the pump and valve. However, in other embodiments, any suitable drive mechanism may be provided to operate the pump and valve. For example, solenoids, nitinol wire, voice coil actuators, piezoelectric motors, wax motors, and / or any other type of motor known in the art may be used to drive the pump. In the preceding example, the pump uses full discharge strokes. However, it should be noted that in other embodiments, a system with sequential incremental discharge strokes can be used to dispense finer doses. In the preceding example, the pump uses on / off limit switches to determine the system state at the limits of its rotational range. However, it should be noted that in other embodiments, other sensors capable of determining intermediate states, such as an encoder wheel and an optical sensor, can be used to improve the resolution of the detection scheme. It should be noted that the internal diameter of the pump can be adjusted to change the nominal output per cycle. In the preceding embodiment, the pump uses elastomeric O-rings. However, it will be appreciated that other arrangements can also be used. For example, fluid seals can be molded directly into the seal carriage, other elastomeric seals, such as quad rings, can be used, or other sealing materials, such as Teflon or polyethylene lip seals, can be used. In alternative embodiments of the invention, the pump movement can be used to initiate or trigger the deployment of the cannula. In the previous example, the system advantageously utilizes a bidirectional drive. The motor's rotation is reversed to alternate between intake and discharge strokes. This provides a safety feature that prevents runaway in the event of a motor malfunction. The motor must alternate rotations to ensure the pump continues to deliver medication from the reservoir. However, it should be noted that in other embodiments, the dosing system is designed to use a unidirectional drive. In the preceding embodiment, the system uses a bag reservoir with two flexible walls. However, in other embodiments, the reservoir can be formed in any suitable way, including with one rigid and one flexible wall. Figure 13 is an exploded view of a dosing subsystem 1300 for a patch pump according to another illustrative embodiment of the present invention. The dosing subsystem 1300 includes a motor and gearbox assembly 1302 and a pump assembly 1304. Figure 14 is an exploded view of pump assembly 1304. Pump assembly 1304 includes a piston 1306 mechanically coupled to a sleeve 1308 via a coupling pin 1310, within a pump manifold 1312. Pump assembly 1304 further includes port seals 1314, a plug 1316, a sleeve rotation limit switch 1318, and an output gear rotation limit switch 1320. Piston 1306 rotates a total of 196° in either direction and can travel approximately 0.038 inches (0.965 mm). Sleeve 1308 and plug 1316 rotate together (as a pair) 56° in either direction. Pump manifold 1312 and port seals 1314 are stationary. Figure 15 is an exploded view of the motor and gearbox assembly 1302. The motor and gearbox assembly 1302 includes a gearbox cover 1322, compound gears 1324, an output gear 1326, shafts 1328, a gearbox base 1330, a motor pinion 1332, and a DC motor 1334. Figures 16A-16D illustrate the assembly and operation of the piston 1306, sleeve 1308, and coupling pin 1310. Figure 16A illustrates the piston 1306, which includes a press-fit bore 1338 that receives the coupling pin 1310, as well as a piston seal 1340, which hermetically seals the piston within the sleeve 1308. The sleeve 1308 includes a helical groove 1342. The piston 1306 is pressed axially into the sleeve 1308, and then the coupling pin 1310 is press-fitted into the bore 1338 through the helical groove 1342. This provides operation similar to the embodiment described above, where rotation of the piston 1306 causes axial translation of the piston 1306 with respect to the sleeve. 1308 due to the interaction of the coupling pin 1310 and the helical groove 1342.Figure 16B illustrates the assembled piston 1306, sleeve 1308, and coupling pin 1310, with the coupling pin 1310 shown at the lower end of the helical groove 1342. Figure 16C illustrates the axial stroke length 1344 of the piston 1306 relative to the sleeve 1308 as a result of the helical groove 1342. Figure 16D illustrates tapered faces 1346 that are preferably provided at the ends of the helical groove 1342 to center the coupling pin 1310 within the groove 1342. Figure 17A illustrates the assembly of plug 1316 with sleeve 1308. As shown, plug 1316 includes a key 1346 and a seal 1348. The seal 1348 provides a snug fit for the plug within the sleeve 1308. The sleeve 1308 is provided with a recess 1350 adapted to receive the key 1346. The key 1346 locks plug 1316 in a twist-fit connection with the sleeve 1308. The plug 1316 is pressed against the (advanced) end face of the piston 1306 during assembly to minimize air in the pump chamber. Friction between the seal 1348 and the inner surface of the sleeve 1308 retains the plug 1316 axially. With the appropriate selection of seal diameters, tightening torque, and materials, the plug 1316 can also serve as an occlusion or overpressure sensor. Pump pressures exceeding the threshold value will cause the plug 1616 to move axially and disengage from the sleeve's rotation limit switch 1318.Friction holds the plug 1316 in position against pressures below a desired threshold. Figures 17B and 17C illustrate the axial movement of the piston 1306 within the sleeve 1308. Figure 17B illustrates the piston 1306 in a first state with a minimum or zero pump volume between the piston 1306 and the plug 1316. As shown, the coupling pin 1310 rests against the lower end of the helical groove 1342. Figure 17C illustrates the piston 1306 in a second state with a maximum pump volume 1352 between the piston 1306 and the plug 1316. As shown, the coupling pin 1310 rests against the upper end of the helical groove 1342. Figures 18A-18D illustrate the mounting of sleeve 1308 on manifold 1312. As illustrated in Figure 18A, manifold 1312 includes port seals 1314 to seal a reservoir port 1354 and a cannula port 1356, respectively. A small side hole 1358 (see Figure 17B) in the sleeve moves back and forth between the two ports, which are 56 degrees apart. As shown in Figure 18B, sleeve 1308 includes a tab 1360, and manifold 1312 includes a corresponding groove 1362 to allow sleeve 1308 to be mounted on manifold 1312. Figure 18C illustrates a manifold window 1364 disposed in the manifold. The tab 1360 is received inside and moves in the window 1364 when the sleeve 1308 is assembled onto the manifold 1312. The tab 1360 and the window 1364 interact to allow the sleeve 1308 to rotate between two positions while preventing axial translation of the sleeve 1308 with respect to the manifold 1312.The sleeve 1308 rotates between a first position in which the side hole 1358 is aligned with the reservoir port 1354 and a second position in which the side hole 1358 is aligned with the cannula port 1356. Figure 18D illustrates the sleeve 1308 assembled on the manifold 1312, with the tab 1360 located inside the manifold window 1364. Figure 19 is a cross-section of the assembled dosing system. As illustrated, the port seals 1314 are face seals compressed between the sleeve 1308 OD and recessed cavities in the manifold 1312. Also illustrated, the tab 1360 is located within the manifold window 1364, and the side hole 1358 is shown at the transition between the reservoir port 1354 and the cannula port 1356. The output gear 1326 includes a cam feature 1366 that engages with the rotation limit switch 1320 to signal the end of the rotational movement of the piston 1306 and sleeve 1308 in either direction. Figures 20A-20E are cross-sectional views illustrating the rotation of the sleeve 1308 within the manifold 1312 to move the side orifice from alignment with the reservoir port 1354 to alignment with the cannula port 1356. Figure 20A illustrates the side orifice 1358 aligned with the reservoir port 1354. While in this position, the piston 1306 moves away from the plug 1316 to fill volume 1352 with fluid from the reservoir. Figure 20B illustrates the sleeve 1308 as it begins to rotate towards the cannula port 1356. In this position, the side hole 1358 is sealed by the seal 1314 in the reservoir port 1354. For this reason, the seal 1314 and the diameter of the side hole 1358 are preferably selected so that the seal 1314 covers the opening of the side hole 1358.Figure 20C illustrates the side hole 1358 of the sleeve 1308 between the reservoir port seal 1314 and the cannula port seal 1314. In this position, neither of the seals 1314 blocks the side hole 1358, but the surface tension of the liquid retains the liquid in the pump chamber. Figure 20D illustrates the side orifice 1358 rotated further to a position where the seal 1314 of the cannula port 1356 covers the opening of the side orifice 1358. Finally, Figure 20E illustrates the side orifice 1358 rotated to align with the cannula port 1356. While in this position, the piston 1306 is axially moved to reduce the volume 1352, forcing the fluid out of the cannula port 1356 and into the cannula. Figures 21A-21C illustrate the operation of the limit switches. As shown in Figure 21A, the plug 1316 includes a cam feature 1368 that interacts with the limit switch 1318. As the sleeve 1308 and plug 1316 rotate, the cam feature 1368 causes the metal flexes of the limit switch 1318 to contact each other until the plug 1316 has rotated completely to the next position. A protrusion 1370 on one of the flexes rests on the cam feature 1368, as illustrated in Figure 21C, when the plug 1316 is at any endpoint of its rotation. The limit switch 1318 opening and closing with each rotational cycle signals that the plug 1316 remains correctly aligned with the limit switch 1318.Under overpressure or occlusion conditions, the increased pressure will cause the plug 1316 to slide out of the sleeve 1308 and become misaligned with the limit switch 1318. This detects overpressure conditions. The limit switch 1320 engages via the cam feature 1366 of the output gear 1326 at each end of the rotational cycle. This signals the motor 1334 to reverse direction. With two metal flexes, as illustrated, it is not possible to determine from the limit switch which rotational cycle has been completed. However, as will be seen, a third flex would allow the engagement direction to be determined. Figures 22A-22C illustrate the motor and gearbox assembly 1302 with the pump assembly 1304. As illustrated in Figures 22A and 22B, the motor and gearbox 1302 include an opening 1372 to receive the rotation limit switch 1320. This allows the output gear 1326, which is inside the gearbox housing, to access and engage the flexures of the limit switch 1320. The motor and gearbox 1302 also include an axial retaining spring 1374 so that the pump assembly 1304 can be press-fitted to the motor and gearbox 1302. The motor and gearbox 1302 include a rotating key 1376 within a pump receiving sleeve 1378 to receive the pump assembly 1304 and prevent rotation of the assembly. pump 1304 in relation to the motor and gearbox 1302.The output gear 1326 includes a groove 1380 (Figure 22B) adapted to receive a tongue 1382 (Figure 22C) provided on the piston 1306. When mounted, the tongue 1382 is received in the groove 1380 so that the output gear 1326 can transmit torque to the piston 1306. As the output gear 1326 rotates, the tongue on the pump piston 1382 rotates and slides axially in the groove. Metal spring flexes on the motor connections and limit switches are used to make electrical contact with pads on a circuit board during final assembly. In operation, the pumping cycle of the embodiment described above includes five stages. First, a pump discharge of approximately 120° (counterclockwise when viewed from the pump toward the gearbox); a valve state change of 56° (counterclockwise); a pump inlet of 140° (clockwise); a valve state change of 56° (clockwise); and a slow advance of approximately 20° (counterclockwise) to clear the limit switch. A complete pump cycle requires 196 degrees of rotation of the output gear in each direction. Figures 23A-30C illustrate a pump cycle. For clarity, only the output gear 1326 of gearbox assembly 1302 is shown in the figures. Figure 23A illustrates an initial position. As shown, the cam 1366 of the output gear 1326 is not in contact with the rotation limit switch 1320, so the flexures are not in contact with each other. The pump piston 1306 is retracted, as shown by the position of the coupling pin 1310 within the helical groove 1342 in Figure 22C. In this position, the sleeve 1308 blocks the flow path from the reservoir, the cannula port 1356 is open to the side hole 1358 of the sleeve 1308, and the rotation limit sensor 1320 and the sleeve sensor 1318 (see Figure 23B) are open. Figures 24A and 24B illustrate the dosing subsystem during a discharge stroke. The output gear 1326 rotates the pump piston 1306 in a first direction of rotation (see the arrow in Figure 24B), which is driven along the helical path of the helical groove 1342 in the sleeve 1308 via the coupling pin 1310 (see Figure 24A). As the pump piston 1306 rotates away from the gearbox, expelling fluid from the pump chamber 1352 and out of the cannula port 1356. During the discharge stroke, the friction between the port seals 1314 and the outer diameter of the sleeve 1308 must be sufficiently high to ensure that the sleeve 1308 does not rotate during this part of the cycle. Figures 25A-25C illustrate the metering subsystem during a valve state change after a discharge stroke. As shown in Figure 25A, after the coupling pin 1310 reaches the distal end of the helical groove 1342, torque continues to be transmitted from the output gear 1326 to the pump piston 1306 and the sleeve 1308 via the coupling pin 1310. The sleeve 1308 and the pump piston 1306 rotate as a unit with no relative axial movement. The side hole 1358 (not shown in Figures 25A-25C) in the sleeve 1308 moves between the reservoir port 1354 and the cannula port 1356. The tab 1360 moves in the direction shown by the arrow inside 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. Figures 26A and 26B show the dosing subsystem in a discharge rotation stop position. The sleeve's side hole 1358 (not shown in Figures 26A or 26B) is aligned with the reservoir port 1354, the pump volume 1352 collapses, and the cannula port 1356 is blocked. The plug 1316 is in a stop position, and the sleeve limit switch 1318 opens. The output gear cam 1366 contacts the rotation limit switch 1320 to signal the end of rotation, such that the output gear 1326 stops to reverse direction. Figures 27A and 27B show the metering subsystem during an intake stroke. The output gear 1326 rotates the pump piston 1306 in the direction shown by the arrow in Figure 27B. The piston 1306 is axially displaced relative to the sleeve 1308 due to the interaction of the coupling pin 1310 within the helical groove 1364. The pump piston 1306 is displaced toward the gearbox, drawing fluid from the reservoir into the pump chamber 1352. During the intake stroke, the friction between the seals and the outer diameter of the sleeve 1308 must be sufficiently high to ensure that the sleeve 1308 does not rotate relative to the manifold 1312. i / 1 / pn / Pznz / zi / YiAi Figures 28A to 28C show the metering subsystem during a valve state change after an intake stroke. The coupling pin 1310 reaches the top of the helical groove 1342, and the motor 1302 continues to deliver torque, causing the sleeve 1308 and piston 1306 to rotate together. The tab 1360 of the sleeve 1308 moves in the direction shown by the arrow in Figure 28A within the window 1364 in the manifold 1312. The cam surface 1368 of the plug 1316 closes the limit switch of the sleeve 1318 when the plug 1316 rotates together with the sleeve 1308. The sleeve 1308 and the pump piston 1306 rotate as a unit with no relative axial movement. During this rotation, the side hole 1358 of the sleeve 1308 moves between the reservoir port 1354 and the cannula port 1356. Figures 29A and 29B show the metering subsystem in an inlet rotation stop position. In this position, the side port 1358 of the sleeve 1308 is aligned with the cannula port 1356, the pump volume 1352 expands, and the reservoir port 1354 is blocked. The cam 1366 of the output gear 1326 engages the rotation limit switch 1320 to signal that rotation is complete. The motor 1302 stops to reverse direction. The sleeve limit switch 1318 is open. Figures 30A-30C show the dosing subsystem after completing a pumping cycle. The output gear cam 1366 is removed from the rotary switch 1320 and is ready to begin another cycle. Figures 31A-31C illustrate another dosing system 3100a according to an exemplary embodiment of the present invention. Figure 31A shows the motor and gearbox assembly 3101, as well as 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 13-30C. Figure 32 is an exploded view of pump assembly 3100. Pump assembly 3100 includes a pump manifold 3102, a port seal 3104, a seal retainer 3106, a piston 3108 that rotates ±196° and translates axially ±0.038, a coupling pin 3110, a sleeve 3112 with conductive pads, and a sleeve rotation limit switch 3114 having flex arms 3128. The sleeve 3112 with conductive pads rotates ±56°, as illustrated. The 3100 pump assembly includes three 3128 flex arms that function as a rotary travel limit switch 3114. The rotary travel limit switch 3114 will be described in more detail below. The rotary travel limit switch 3114 senses the position of the sleeve 3112 directly, rather than the position of the output gear. This allows for more precise angular alignment of the sleeve 3112 with respect to the i / 1 / pn / Pznz / zi / YiAi manifold 3102 and the cannula port. Figures 33A-33B illustrate the assembly of piston 3108 in sleeve 3112. In this embodiment, an inner wall 3113 in sleeve 3112 forms the front face of the pump chamber. The features of the piston sleeve are designed with tolerances to minimize the gap between the end face of piston 3108 and the face of the inner wall 3113 of the sleeve. Figures 34A-34E illustrate the assembly of sleeve 3108 into manifold 3102. As illustrated in port seal 3104, seal retainer 3106 and sleeve 3112 are inserted into manifold 3102. A small side hole 3115 (see Figure 34E) in sleeve 3112 moves back and forth between a reservoir port and a cannula port, which are preferably separated by 56 degrees. Sleeve 3112 is inserted past a retaining tab 3116 (see Figure 34D) into manifold 3102 and then rotated into position to prevent axial displacement. Because this embodiment prevents or minimizes axial movement of the plug, axial plug movement occlusion detection is typically not provided. Figure 35 illustrates a cross-section of the sleeve assembly 3112 and manifold 3102 taken through the port seal 3104 and through the shafts of the side ports to the manifold 3102. The side ports to the manifold 3102 include the cannula port 3118 and the reservoir port 3120. The port seal 3104 is a face seal, which is compressed between the outer diameter of the sleeve 3112 and a recessed pocket in the manifold 3102. Figures 36A-36C are cross-sections through the axes of the side ports as sleeve 3112 rotates from reservoir port 3120 to cannula port 3118, illustrating the valve's state change. In the initial position shown in Figure 36A, the side port of sleeve 3115 is open to reservoir port 3120. In this position, cannula port 3118 is blocked. In the intermediate position shown in Figure 36B, the side port of sleeve 3115 is blocked by the seal of port 3104 during the transition. In the final position shown in Figure 36C, the side port of sleeve 3115 is open to cannula port 3118. In this position, reservoir port 3120 is blocked. Figures 37a-37D illustrate the operation of the sleeve rotation limit switch 3114. A three-contact switch design allows the patch system to distinguish between the two rotation limits via input signals from the switch, rather than tracking the sleeve's angular orientation through software. Collector 3102 preferably includes collector mounting posts 3122. The contacts of switch 3114 are attached to the posts 3122 with adhesive, ultrasonic welding, thermal staking, or any other suitable bonding method. Sleeve 3112 includes conductive pads 3124 at the sleeve end i / 1 / pn / Pznz / zi / YiAi 3112. These may be printed or overmolded metal inserts, or may be provided by any other suitable means. The sleeve rotation limit switch 3114 includes a plastic overmold 3126 for the separation and mounting features of the flexes. The sleeve rotation limit switch 3114 also includes three metal flexes 3128. The collector 3102 is provided with alignment grooves 3130, which receive the flexes 3128. In a first position, shown in Figure 37B, the side hole 3115 in the sleeve 3112 is aligned with the cannula port 3118. In this position, a conductive pad 3124 in the sleeve 3112 links the center and right contacts 3128a, 3128b. In the middle position, shown in Figure 37C, the side hole 3115 in the sleeve 3112 is halfway between ports 3118 and 3120. In this position, both sides of switch 3114 are open.In the final position, shown in Figure 37D, the side hole 3115 in the sleeve 3112 is aligned with the reservoir port 3120. In this position, the conductive pad 3124 in the sleeve 3112 connects the center and left contacts, 3128b, 3128c. The pump described above has a modified operating sequence. The operating sequence is substantially the same as described above, except that the 20° reverse stroke is no longer required. The reverse impulse is not required with the three-contact switch design described above, and a complete pump cycle consists of the following four segments. First, there is an approximately 140° pump discharge, which is counterclockwise when viewed from the pump toward the gearbox. Second, there is a 56° valve change of state, also counterclockwise. Third, there is a 140° pump inlet, which is clockwise. Fourth, there is a 56° valve change of state, clockwise.The total pump cycle requires 196 degrees of rotation of the output gear in each direction. Figures 38A and 38B illustrate an exploded view of another version of the pump assembly with an elastomeric port and piston seals overmolded onto the pump manifold and piston, respectively. This version of the pump operates substantially identically to the one described above, but has fewer discrete components and is easier to assemble. Overmolding the seals directly onto the manifold and piston reduces the number of dimensions contributing to seal compression, allowing for tighter control and less variability in seal performance. Figure 39A illustrates an exploded view of a 3900 pump assembly with an alternative rotation limit switch design. This version of the pump assembly includes a two-contact design for the sleeve rotation limit switch. With this design, the pump would properly retract at the end of a pumping cycle, so that the contact switch 3902 would be open in the rest state. As illustrated in Figure 39B, in a first position, the side hole 3115 in the sleeve is aligned with the cannula port. In this position, a first rib 3904 in the sleeve forces the contracts closed. In the mid-position shown in Figure 39C, the side hole 3115 in the sleeve is halfway between the ports, and none of the ribs 3904, 3906 touch the contact switch 3902, so it is open.In a third position shown in Figure 39D, the side hole 3115 in the sleeve is aligned with the reservoir port. In this position, a second rib 3906 in the sleeve again forces the contact switch 3902 to close. Figure 40 is an exploded view of another embodiment of a dosing assembly 4000. This embodiment shares substantial similarities with the embodiments described above, so the following description focuses on the differences. The dosing assembly 4000 includes a sleeve 4002 having a helical groove 4004, a plug 4006, seals 4008, a plunger 4010, a coupling pin 4012, a manifold 4014, a port seal 4016, and a flexible interlock 4018. Figure 41 illustrates the dosing assembly in its assembled form. The seals 4008 are preferably formed from an elastomeric material and are of unitary construction. One seal 4008 is mounted on plug 4006 and the other seal 4008 is mounted on plunger 4010. Plug 4006 is preferably secured to sleeve 4002 by gluing, heat sealing, or any other suitable means. One end face of the plug forms a surface of the pump volume.The plunger 4010 is inserted into the sleeve 4002, and the coupling pin 4012 is press-fitted onto the plunger 4010 and extends into the helical groove 4004 to provide axial translation of the plunger 4010 as the motor rotates (not shown). One end face of the plunger 4010 forms an opposite surface of the pump volume. The port seal 4016 is preferably a single molded piece of elastomeric material. This embodiment reduced the number of parts and improved manufacturability. Figure 42 is a cross-section of the assembled metering assembly. Figures 43A-43C illustrate the interaction of the interlock 4018 with the sleeve 4002. As shown in Figure 41, the interlock 4018 is mounted on the manifold 4014 at either end of the interlock 4018. As shown in Figure 43A, one end face of the sleeve 4002 includes a retainer 4020 that is adjacent to a protrusion 4022 of the interlock 4018 when the metering assembly is in a first position (side hole aligned with the tank pump). Under certain conditions, such as back pressure, friction between piston 4010 and sleeve 4008 may be sufficient to cause the sleeve to rotate before plunger 4010 and coupling pin 4012 reach either end of helical groove 4004. This could result in an incomplete volume 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 coupling pin 4012 reaches the end of the helical groove 4004. Once the coupling pin strikes the end of the helical groove 4004, further motor movement increases the torque on the sleeve beyond the threshold, causing the interlock to flex and allow the retainer 4020 to pass through the protrusion 4022. This is illustrated in Figure 43B. Upon completion of the rotation of sleeve 4008 so that the side hole is oriented with the cannula port, the retainer 4020 moves past the protrusion 4022 in the interlock 4018. This is illustrated in Figure 43C. Figure 44 illustrates a cross-section of another example embodiment of a dosing system 4400. The dosing system 4400 includes a modified sleeve 4402 having a face 4404 that forms a surface of the pump volume. This embodiment eliminates the need for a plug as in the previous embodiment and simplifies manufacturing. Figure 45 illustrates another example 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 retainer 4504 similar to the sleeve described above for interacting with an interlock (not shown). The switching mechanism 4502 includes a limit switch arm 4506 adapted to rotate in any direction away from its neutral position. The sleeve 4500 includes a switching lever (actuating arm) 4508 adapted to interact with the limit switch 4506 as the sleeve 4500 rotates. Figure 47 illustrates how the limit switch 4506 rotates about an axis. The switching mechanism 4502 provides electrical signals to indicate the position of the limit switch 4506.Figure 48 is a top view illustrating the sleeve 4500 rotated to an orientation where the limit switch 4506 has rotated to its maximum angle (α) from the neutral position. Further rotation of the sleeve causes the limit switch 4506 to disengage from the actuating arm 4508 and return to its neutral position. This change in the orientation of the switch arm signals the end of the sleeve 4500's rotation in one direction and causes the rotary metering pump to reverse. Figure 49 is a side elevation view facing the sleeve, illustrating the same interaction between the limit switch 4506 and the actuating arm 4508. Figure 50 is a side elevation view showing the sleeve 4500 and switching mechanism 4502 incorporated into a patch pump, along with the locking collar 4510. Figure 51A illustrates the relative angular positions of the limit switch 4506 and the actuating arm 4508. Alpha (α) is the angle of the limit switch 4506. Beta (β) is the angle of the rotating sleeve and the actuating arm. Figure 51B illustrates the relative change d(α) / d(β) versus β. The reversal is preferably activated at β = 33°. As illustrated, as the actuating arm 4508 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 the neutral position (β = 0°), thus initiating a reversal of the rotary pump. The same procedure occurs in reverse when the sleeve 4508 rotates in the other direction. Consequently, the sleeve moves alternately from one side to the other. The following describes improved portions of the pump plunger and plug in relation to Figures 52-67. As will now be described, the improved plunger 5210 and pump bottom 5206 improve the pump by making these parts easier to manufacture and assemble, and by eliminating a potential source of fluid leakage from the earlier design. The plunger 5210 is illustrated in multiple views in Figures 52-58. The plunger 5210 is substantially similar to the plunger 4010 illustrated in Figure 40, except that the butt gasket 4008 is not required because a seal, which will be described below, is overmolded onto the head 5212 of the plunger 5210. The seal 5214 is illustrated in multiple views in Figures 59-62. The seal 5214 is advantageously overmolded onto the plunger head 5212 of the plunger 5210. Consequently, the sealed plunger is advantageously manufactured in a two-stage molding process. The plunger 5210 is molded from a rigid plastic material, and then the seal 5214 is molded from a viscoelastic elastomer onto the plunger 5210 as a second stage. The combined plunger 5210 and seal 5214 are more easily assembled into the overall pump and reduce the potential for leakage present with an O-ring design. Figures 63-67 illustrate a pump stop or plug 5206. Stop 5206 corresponds substantially to plug 4006 in Figure 40, except that a seal 5214 (the same or substantially similar seal for both plunger 5210 and plug 5206) is overmolded onto the head 5208 of plug 5206 instead of an O-ring. Similar to the plunger 5210 described above, plug 5206 and seal 5214 are preferably manufactured in a two-stage molding process. Plug 5206 is molded from rigid plastic material, and seal 5214 is molded from a viscoelastic elastomer onto plug 5206 as a second stage. Figure 68 illustrates an exploded view of the dosing assembly 4000, but with the improved plunger 5210, plug 5206, and seals 5214. Those skilled in the art will appreciate that just as plug 4006 was optional in the earlier design and could be replaced with a wall 4404 as illustrated in Figure 44, plug 5206 is optional and replaceable with a similar wall. A method 6900 for manufacturing and assembling a pump according to an exemplary embodiment of the invention using the overmolded parts described above will now be described with reference to Figure 69. First, a rigid plastic plunger is molded in step 6902. Next, a seal is overmolded onto a plunger head in step 6904. The seal is molded from a viscoelastic elastomer and is sized to fit within and seal a pump chamber. Optionally, a rigid plastic pump plug is molded in step 6906, and a seal is overmolded onto the pump plug head in step 6908. The plunger and pump plug are inserted into a pump chamber of a pump in step 6910. A pin is inserted into a hole in the plunger to allow axial translation of the plunger as the pump motor rotates the pump chamber in step 6912. A further embodiment of the invention is illustrated in Figures 70A-70L. 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 first rotate the plunger, causing the plunger to advance or retract due to the movement of the coupling pin within a helical groove in the sleeve. Thus, after the coupling pin reaches the end of the groove (either end, depending on the direction of rotation), further rotation causes the plunger and sleeve to rotate together, reorienting the sleeve relative to the collector. As described above, however, in practice, friction or other forces may cause the movements to occur out of sequence.If the forces between the plunger and the sleeve are too large and are not mitigated, the plunger and sleeve may initially rotate together before the plunger moves relative to the sleeve. Figures 40-43C illustrate a flexible interlock that initially resists sleeve rotation until the plunger has fully advanced or retracted. Figures 70A-70L illustrate an alternative embodiment of the pumps described herein in which an alternative shuttle can be included in the pump mechanism to replace the flexible interlock. The alternative shuttle is independent of the flexibility or other properties of an interlocking component and advantageously makes the pump mechanism deterministically sequencing correctly with greater reliability. An example alternative shuttle is described below. Figures 70A-70L schematically illustrate the sleeve 7001, the output gear 7002, a coupling pin 7003, a helical groove 7004, and a reciprocating shuttle 7005. In order to illustrate the shuttle motion, a target or dot on the shuttle is shown. 7005 indicates movement away from the drawing surface along an axis perpendicular to the drawing, and an ox cross on the shuttle indicates movement toward the drawing surface. It is understood, as described above, that the movement of the coupling pin 7003 within the helical groove 7004 corresponds to the axial movement of the plunger within the sleeve, causing the pump chamber to increase or decrease in volume. In the illustrated embodiment, when shuttle 7005 retracts into the drawing surface, it does not interfere with the rotation of sleeve 7001, and when shuttle 7005 advances out of the drawing surface, it prevents the rotation of sleeve 7001 by interfering with the movement of a retainer 7006. Figures 7C, 7D, 7I, and 7J illustrate portions of the sequence in which shuttle 7005 interferes with the rotation of sleeve 7001. However, the advanced / retracted positions could be reversed, if desired, and an embodiment could still function as intended provided the shuttle blocks or permits the rotation of the sleeve at the correct times in the pumping sequence. The pumping sequence with shuttle movement 7005 will now be described in detail. Figure 70A illustrates an initial position in the pumping sequence. The sleeve 7001 is in a first position with, for example, an inlet port aligned with a reservoir port of the manifold. The plunger and pin 7003 are in the initial position with the pump reservoir in the empty configuration. The output gear 7002 is in the initial position, ready to begin the first part of its reciprocating rotation. The shuttle 7005 is fully retracted in the drawing so that it does not interfere with the movement of the retainer 7006. Figure 70B illustrates the beginning of the rotation of the output gear 7002. Preferably, during this part, the coupling pin 7003 moves within the groove 7004, causing the plunger to retract and the pump chamber to increase in volume. However, the sleeve 7001 may tend to rotate along with the output gear due to friction or other forces. Through 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 advance in a direction away from the drawing surface. As illustrated in Figure 70C, due to the cam or other interaction between the output gear and the shuttle, the shuttle advances completely and has been shown to lock the retainer 7006 from further rotation while 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 groove 7004. At the same time, the sleeve 7001 and its retainer 7006 remain stationary, as illustrated in 70D. As illustrated in Figure 70E, at this stage, a cam (or other suitable interaction of the output gear and shuttle) causes the shuttle 7005 to retract to the drawing surface. As a result, the sleeve 7001 and retainer 7006 are allowed to rotate. Figure 70F illustrates the output gear 7002, coupling pin 7003, and sleeve 7001 rotating together to move the sleeve to orient its port from the inlet position relative to the manifold to the outlet position. Figure 70G illustrates the pump mechanism at the end of the first half of the reciprocating motion.Sleeve 7001 rotates completely to the exit position with respect to the collector and shuttle 7005 remains retracted. Figure 70H illustrates the beginning of the reciprocating motion back to the initial position. The output gear 7002, coupling pin 7003, and potentially the sleeve 7001 begin to rotate counterclockwise. Due to cam interaction (or other suitable interaction between the output gear and the shuttle), the shuttle 7005 begins to advance again in a direction not shown in the drawing. Figure 70I illustrates a portion of the sequence in which the shuttle 7005 has fully advanced again, preventing the sleeve 7001 from rotating, while the output gear 7002 and coupling pin 7003 rotate counterclockwise.Figure 70J illustrates a specific portion of the sequence in which the coupling pin 7003 has fully rotated within the helical groove 7004, causing the pump chamber to shrink and expel fluid through the manifold outlet port. Figure 70K illustrates that as the output gear 7002 continues to rotate clockwise, the cam (or other suitable interaction between the output gear and the shuttle) causes the shuttle 7005 to retract into the surface shown in the drawing. Figure 70L illustrates the fully retracted shuttle 7005, and the output gear 7002, coupling pin 7003, and sleeve 7001 all rotating together to return to the initial position illustrated in Figure 70A. This is the complete pumping sequence, which can be repeated as needed to supply medical fluid from the reservoir through the pumping chamber and up to an outlet port. Figure 71 illustrates an exploded view of an output gear assembly 7002 and shuttle 7005, which causes the shuttle to move alternately forward and backward at the appropriate times relative to the rest of the pump assembly. The shuttle 7005 includes a shuttle pin 7009. The shuttle pin 7009 is illustrated, but, of course, any other interlocking or connecting structure could suffice, as someone skilled in the art will appreciate. The output gear 7002 includes a cam structure 7007 which further includes a shuttle cam groove 7008. The shuttle pin 7009 is received in the shuttle cam groove 7008 and, consequently, as the output gear 7002 rotates, the shuttle 7005 advances and retreats in the directions indicated by the arrows when the shuttle pin 7009 is forced to move within the shuttle cam groove 7008.Figures 72A-72C illustrate this movement more clearly. It should be noted that the structure for restricting the movement of shuttle 7005 in a direction other than that indicated by the arrows in Figure 71 should, of course, be included, but is not shown here for simplicity. In Figure 72A, the output gear 7002 is ready to begin rotating in one direction, and shuttle 7005 is in the fully retracted position. The shuttle pin 7009 is at the other end of the shuttle cam groove 7008. As illustrated in Figure 72B, the output gear 7002 is halfway through its rotation in this direction, and shuttle 7005 has advanced to its fully extended position through the interaction of the shuttle pin 7009 and the shuttle cam groove 7008. Figure 72C illustrates the end of the first rotation of the output gear 7002.In this position, the shuttle 7005 is again fully retracted, and the shuttle pin 7009 is at the opposite end of the shuttle cam groove 7008. As a person skilled in the art will appreciate, this example illustrates a sample mechanical arrangement for achieving regular and deterministic advance and retraction of the shuttle to block or permit rotation of the sleeve as described above. Any other mechanical arrangement suitable for providing advance, retraction of the shuttle, and correct timing with sleeve rotation is considered to be within the scope of a person skilled in the art. Another example embodiment will now be described in relation to Figures 73-82. This embodiment simplifies the embodiments described above, in particular by eliminating the need for an interlock to achieve the correct piston sequence and sleeve assembly rotation, while increasing insulin compatibility by reducing the harmful effects of shear forces on insulin molecules flowing through the pump when the parts slide against each other. This embodiment can advantageously reduce hydrophobic surface contact and have less than 10% hydrophobic surface contact compared to the earlier designs. The increased sealing pressure in this embodiment causes less damage to insulin trapped between the sealing surfaces.Optional notches in the gasket, which will be described in more detail below, eliminate shearing of a significant portion of the wetted surfaces, further reducing damage to the insulin molecules. Parts of the pump that are substantially similar to the embodiments described above are not repeated here for the sake of brevity and clarity. This embodiment also eliminates the need for a manifold. For example, the interaction of the helical groove and the pin that causes the piston to move alternately, the interaction of the gearbox with the piston assembly, and the limit switch that causes the motor to reverse direction remain substantially unchanged in the following embodiment. i / 1 / pn / Pznz / zi / YiAi Figure 73 illustrates an exploded view of the modified sleeve 7301, gasket 7302, and pump housing 7303, which are components of the present embodiment. In this embodiment, the pump housing includes a cylindrical inner surface 7304 dimensioned to receive a substantially cylindrical gasket 7302. The gasket 7302, in turn, is assembled into a gasket-receiving portion 7305 of the modified sleeve 7301. The piston 7306, as shown, is substantially the same as that described above. The gasket 7302 has an opening 7307 that receives the opening 7309 in the sleeve 7301 when assembled. The gasket 7302 also preferably has a second opening 7308 arranged opposite the opening 7307. The second opening 7308 is not strictly necessary, but it improves ease of assembly and also serves to reduce the contact surface area between the gasket 7302 and the inner surface 7304 of the housing 7303. Figure 74 illustrates the pump assembly 7300 oriented with the sleeve opening 7309 aligned with the inlet port 7310 of the pump housing 7303. Figure 75 is a cross-sectional view of the assembly 7300 with the sleeve opening 7309 positioned midway between the intake state, when the sleeve opening 7309 is aligned with the inlet port 7310, and the outlet state, when the sleeve opening 7309 is aligned with the outlet port 7311. In this intermediate state, gasket 7302 seals the sleeve 7301 tightly to the housing 7303. The piston seals 7312 function substantially as described above. Figure 76 illustrates the pump assembly 7300 oriented with the sleeve opening 7309 aligned with the outlet port 7311 of the pump housing 7303. Figure 77 illustrates the pump assembly 7300 oriented with the sleeve opening 7309 aligned halfway between the inlet port 7310 and the outlet port 7311 of the pump housing 7303. Figure 78 is a cross-sectional view illustrating the sleeve opening 7309 and the gasket opening 3707 aligned midway between the inlet port 7310 and the outlet port 7311. The piston surface 7313 is also shown. Figure 79 is a cross-sectional view illustrating the sleeve opening 7309 and the gasket opening 3707 aligned with the outlet port 7311. Figure 80 illustrates one embodiment of gasket 7302. This version includes gasket opening 7307 and an opposing gasket opening 7308. Figure 81 illustrates a second embodiment of the gasket with added notches 7314 on both sides of openings 7307, 7308. These notches reduce the surface contact area between gasket 7302 and the cylindrical inner surface 7304 of housing 7303. The notches 7314 thus reduce friction and minimize the deterioration of insulin molecules caused by shearing when the gasket surfaces are wet. 7302 slide against the housing surfaces 7303. Figure 82 illustrates the gasket 7302 with notches 7314 on both sides of the sleeve opening 7309 when the pump assembly 7300 is oriented with the sleeve opening 7309 aligned with the inlet port 7310. As will be seen, the pump's operation is substantially similar to that described above. That is, as the motor rotates in one direction, friction between gasket 7302 and housing 7303 prevents relative rotation. The pin and helical groove cause the pump chamber to expand because the opening of sleeve 7309 aligns with the inlet port 7310, which is fluidly connected to the insulin reservoir. Once the pin reaches the end of the helical groove (described above), the motor's continued rotation forces sleeve 7301 to rotate until the opening of sleeve 7309 aligns with the outlet port 7311. After this part of the cycle is completed, the motor reverses direction by operating the limit switch (described earlier).As the motor begins to rotate in the opposite direction, friction between gasket 7302 and housing 7303 prevents relative rotation, and the pump chamber contracts due to the interaction of the helical groove and the pin. This forces insulin from the pump chamber, through the sleeve orifice 7309 and out the outlet port 7311 for delivery. Once the limit switch is activated again, the cycle is complete and begins to repeat. Although only a few illustrative embodiments of the present invention have been described in detail above, those skilled in the art will readily appreciate that many modifications to the illustrative embodiments are possible, and various combinations of the illustrative embodiments are possible, without materially departing from the new lessons and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention.

Claims

1. A rotary dosing pump, comprising: a sleeve comprising a side bore, the sleeve receiving a seal having a first seal opening disposed around the side bore, the sleeve and seal being adapted to rotate axially within a housing having an inlet port connected to a fluid reservoir and an outlet port connected to a supply cannula; the sleeve further comprising a helical groove having a first end and a second end;a plunger received within the sleeve and adapted to rotate and translate axially within the sleeve, wherein the axial translation of the plunger within the sleeve changes the pump volume, the pump volume being in fluid communication with the side orifice of the sleeve, the plunger further comprising a coupling element adapted to move within the helical groove and between the first and second ends of the helical groove to cause the plunger to translate axially within the sleeve when the plunger rotates; a motor adapted to rotate the plunger in a first direction, thereby increasing the pump volume when the sleeve is in the first orientation, and to rotate the sleeve and plunger together when the coupling element reaches the first end of the helical groove, so that the sleeve moves to the second orientation; an output gear transmitting motion from the motor to the plunger;where the gasket forms a seal between the sleeve and the housing that allows fluid to pass through the first opening of the gasket between the pump volume and the inlet port or outlet port.

2. The rotary dosing pump of claim 1, wherein the seal further comprises a second opening for the seal disposed opposite the first opening of the seal.

3. The rotary dosing pump of claim 1, wherein the seal further comprises notches on both sides of the first seal opening that are oriented towards the housing.

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