Subcutaneous insertion mechanism with pre-energized release and automatic retraction via latch member - Patents.com

Abstract

An insertion mechanism with increased reliability and reduced components is provided. The insertion mechanism engages the needle hub and catheter hub using a single engagement and release clip compressed within the insertion mechanism housing. A button is provided that moves the catheter hub and needle hub distally until the engagement and release clip reaches a firing window in the mechanism housing. The engagement and release clip expands within the release window to release the needle hub from the catheter hub and a return spring allows the insertion needle to move proximally while the catheter remains inserted and also holds the catheter hub in the deployed position.

Description

Technical Field

[0001] Related Applications This application claims priority to U.S. Provisional Application No. 63 / 214,545, filed on Jun. 24, 2021, including its specification, drawings, and abstract, the entire disclosure of which is incorporated herein by reference.

[0002] Technical Field The present invention generally relates to medical infusion systems such as insulin infusion devices or insertion devices, where a simple, low-profile, low-part count manual insertion device is provided for subcutaneously inserting a cannula with automatic introducer needle retraction.

Background Art

[0003] Diabetes is a group of diseases characterized by high levels of blood glucose resulting from the inability of a diabetic patient to maintain appropriate levels of insulin production when needed. Diabetic patients require some form of daily insulin therapy to maintain control of their glucose levels. Diabetes can be dangerous to affected patients if left untreated and can lead to serious complications and premature death. However, such complications can be minimized by using one or more treatment options that help control diabetes and reduce the risk of complications.

[0004] Treatment options for diabetic patients include special diet therapies, oral medications, and / or insulin therapy. The main objective of diabetes treatment is to control the blood glucose or sugar levels of diabetic patients. However, maintaining appropriate diabetes management can be difficult because diabetic patients must balance their activities.

[0005] There are two main methods of daily insulin therapy for the treatment of type 1 diabetes. In the first method, diabetic patients self-inject insulin using a syringe or insulin pen as needed. This method requires needle pricks with each injection, and diabetic patients may need 3 to 4 injections a day. The syringes and insulin pens used to inject insulin are relatively easy to use and cost-effective.

[0006] Another effective method for insulin therapy and diabetes management is infusion therapy or infusion pump therapy using an insulin pump. An insulin pump can provide a continuous infusion of insulin to a diabetic patient at various rates in order to approximate the function and behavior of a properly functioning pancreas in a non-diabetic person that produces the required insulin, and the insulin pump can help a diabetic patient maintain their blood sugar level within the target range based on the individual needs of the diabetic patient.

[0007] Infusion pump therapy requires an infusion cannula, typically in the form of an infusion needle or a flexible catheter, which penetrates the skin of the diabetic patient, thereby enabling the infusion of insulin. Infusion pump therapy has advantages such as continuous infusion of insulin, accurate dosing, and a programmable delivery schedule.

[0008] In infusion therapy, insulin administration is typically given at a basal rate and as a bolus dose. When insulin is administered at a basal rate, the insulin is delivered continuously over 24 hours to maintain the blood glucose level of a diabetic patient within a consistent range during meals and rest, typically at night. Insulin pumps can also program the basal rate of insulin to vary according to different times of day and night. In contrast, a bolus dose is typically administered when a diabetic patient eats a meal and generally provides a single additional insulin injection to balance the carbohydrates consumed. Insulin pumps can be configured to enable a diabetic patient to program the volume of the bolus dose according to the size or type of meal consumed by the diabetic patient. In addition, insulin pumps can also be configured to enable a diabetic patient to inject a correction or supplemental bolus dose of insulin to compensate for low blood glucose levels when the diabetic patient is calculating the bolus dose for a particular meal consumed.

[0009] Insulin pumps advantageously deliver insulin over time rather than as a single injection and typically have less variability within the recommended blood glucose range. In addition, insulin pumps can reduce the number of needle sticks that a diabetic patient has to endure, improve diabetes management, and enhance the quality of life of a diabetic patient.

[0010] Typically, whether a diabetic patient uses multiple direct injections (MDI) or a pump, the diabetic patient performs fasting blood glucose medication (FBGM) when waking up from sleep and also tests for blood glucose at or after each meal to determine whether a correction dose is needed. In addition, the diabetic patient can test for blood glucose before sleep to determine, for example, whether a correction dose is needed after having a snack and before sleep.

[0011] To facilitate infusion therapy, there are generally two types of insulin pumps, namely, conventional pumps and patch pumps. Conventional pumps typically require the use of disposable components, often referred to as infusion sets, tubing sets, or pump sets, which carry insulin from a reservoir within the pump into the user's skin. An infusion set consists of a pump connector, a length of tubing, and a hub or base from which a cannula in the form of a hollow metal injection needle or a flexible plastic catheter extends. The base typically has an adhesive that holds the base on the skin surface during use. The cannula can be inserted into the skin manually or using a manual or automatic insertion device. The insertion device can be a separate unit required by the user.

[0012] Another type of insulin pump is the patch pump. Unlike the combination of a conventional infusion pump and infusion set, a patch pump is an integrated device that adhesively attaches most or all of the fluid components, including a fluid reservoir, a pump mechanism, and a mechanism for automatically inserting the cannula, to an infusion site on the patient's skin and combines them in a single housing that does not require the use of a separate infusion or tubing set. A patch pump containing insulin adheres to the skin and delivers insulin over a period of time via an integrated subcutaneous cannula. Some patch pumps may communicate wirelessly with a separate controller device (as in one device sold under the brand name OmniPod by Insulet Corporation), while other patch pumps are completely self - contained. Such devices are changed frequently, such as every three days, when the insulin reservoir is emptied or when complications, such as restrictions in the cannula or infusion site, may occur.

[0013] The patch pump is designed to be a self - contained unit worn by diabetic patients, so it is preferably made as small as possible so as not to interfere with the user's activities. Therefore, in order to minimize discomfort to the user, it is preferable to minimize the overall thickness of the patch pump. However, in order to minimize the thickness of the patch pump, its components need to be reduced as much as possible. One such component is an insertion mechanism for automatically inserting the cannula into the user's skin.

[0014] To minimize the height of the insertion mechanism, some conventional insertion mechanisms are configured to insert the cannula at an acute angle, such as 30 - 45 degrees, from the surface of the skin. However, there may be cases where it is preferable to insert the cannula perpendicular or almost perpendicular to the surface of the skin, because this requires the minimum insertion length of the cannula. In other words, when the cannula of minimum length is inserted into the user's skin, the user may experience greater comfort and fewer complications, such as early kinking of the cannula. However, one problem with configuring the insertion mechanism to insert the cannula perpendicular to the surface of the skin is that this can increase the overall height of the insertion mechanism and thus the height of the patch pump itself.

[0015] Therefore, in order to reduce the overall height of a device incorporating an insertion mechanism, such as a patch pump, an improved insertion mechanism is needed that can cost - effectively insert the cannula perpendicular or almost perpendicular to the surface of the user's skin while minimizing or reducing its height, for use in a limited - space environment such as within a patch pump. SUMMARY OF THE INVENTION

[0016] The object of the present invention is to substantially address the above and other concerns and to facilitate the insertion of an indwelling or flexible catheter and the retraction of an introducer needle while reducing the number of components required for the structure and use of the insertion device, by providing advanced, improved, novel components and elements of the insertion device.

[0017] Another object of the present invention is to provide a manual insertion device with at least automatic introducer needle retraction that helps to keep component manufacturing costs low and simplifies device assembly so that the number of parts in an exemplary embodiment is reduced. The automatic retraction also simplifies the user interface by minimizing the number of user steps for activation. There is only one step for the user, which is to press a button.

[0018] These and other objects are substantially achieved by providing an insertion device comprising a housing having at least one release window in a distal portion of the housing, a flexible firing arm, a button slidable within the housing from an initial proximal position to a distal position, a catheter hub fixed to the catheter, a needle hub fixed to the insertion needle, the insertion needle being inserted into the catheter in an initial configuration, an engagement and release clip that is larger than the inside of the housing in a relaxed state, compressed inside the housing, and engages the catheter hub with the needle hub in a compressed state, and a return spring that biases the needle hub in a proximal direction and is compressed when the button moves distally. The firing arm prevents movement of the button in the distal direction until a predetermined force is applied to the button, bending and releasing the button to the firing arm. The engagement and release clip expands towards its relaxed configuration when the button is pushed distally and the release and engagement clip is aligned with the release window, and the return spring moves the hub to a final proximal position when the engagement and release clip expands, thereby releasing the hub from the catheter hub.

[0019] Additional and / or other aspects and advantages of the present invention will be set forth in the description which follows, or will become apparent which follows, or will become apparent by practice of the invention. The invention may include a method or apparatus or system having one or more of the aspects above and / or one or more of the features above, and combinations thereof. The invention may include, for example, one or more features and / or combinations of the aspects above as set forth in the appended claims.

Brief Description of the Drawings

[0020] Various objectives, advantages, and novel features of exemplary embodiments of the present invention will be more readily understood from the following detailed description when read in conjunction with the accompanying drawings.

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[0021] Throughout the drawings, like reference numerals will be understood to refer to like parts, components, and structures.

DETAILED DESCRIPTION OF THE INVENTION

[0022] The exemplary embodiments of the present invention described below provide new means for providing one or more infusion device elements configured to insert a catheter up to 8 mm into the skin surface, but the embodiments are not limited thereto. The insertion device is configured to perform manual insertion of the catheter, which allows the insertion device to be smaller, simpler, and less expensive than an automatic or spring-assisted insertion device.

[0023] The exemplary embodiments of the present invention described below utilize a manual insertion device and include a dual retraction spring configuration for automatic introducer needle retraction that also enables a very small device size. The dual retraction spring configuration is implemented using a plurality of cylindrical or barrel-shaped guides. In an exemplary embodiment, one barrel guides the button and catheter, and an adjacent barrel houses one retraction spring on each side of the button and catheter. Having the springs in separate barrels enables springs that are much smaller than a single barrel configuration where the springs are coaxial with the catheter. A single coaxial spring enables access to the button assembly because the limitations of spring design require the spring to extend from approximately the bottom to the top of the housing. When access is required for functions such as a locking arm and the function is implemented inside the spring, the entire mechanism has to be enlarged to accommodate them, which increases the footprint of the mechanism.

[0024] Figures 1 and 2 show the insertion device before use, and Figure 3 shows the device after cannula deployment. As shown in Figures 1 - 3, the insertion device includes a top housing 100 and a base 102. The top housing 100 is shown to have an opening 104 through an upper surface from which a user-accessible and user-actuable button 200 extends slidably. The contents of the insertion device, including the mechanism housing 300, are shown in more detail in Figure 4. The top housing 100, button 200, and mechanism housing 300 can be manufactured from ABS, and the base 102 can be manufactured from PETG, but the embodiments are not limited thereto.

[0025] As shown in FIG. 4, an exemplary insertion device is assembled by stacking together several sub-assemblies captured between an upper housing 100 and a mechanism housing 300. FIG. 4 is a view of the insertion device of FIG. 1 according to an embodiment of the present invention. The sub-assemblies shown in FIG. 4, and described in more detail below, include a catheter / partition sub-assembly, an introducer needle sub-assembly, and a button sub-assembly. Other features and functions of the insertion device well known to those skilled in the art are omitted from the drawings and description for clarity.

[0026] An exemplary catheter / partition sub-assembly is shown in FIG. 5. FIG. 5 is a cross-sectional view of the catheter / partition sub-assembly of the insertion device of FIG. 1 according to an embodiment of the present invention. As shown in FIG. 5, the catheter / partition sub-assembly is assembled by attaching a catheter 202 to a metal wedge 204, then inserting a partition 206 into the wedge and capturing it between a release collar 208 and a catheter wedge cap 210. The partition 206 is radially compressed by the wedge 204 and axially compressed by the release collar 208 to create a seal between the partition 206 and the wedge 204. The catheter 202 can be a 24G plastic catheter manufactured using FEP, and the release collar 208 and catheter wedge cap 210 can be manufactured using PTEG, although the embodiments are not limited thereto. The wedge 204 can be manufactured using 305 stainless steel, and the partition 206 can be manufactured using isoprene, although the embodiments are not limited thereto.

[0027] An exemplary introducer needle subassembly is shown in FIGS. 6 and 7. FIG. 6 is a view of an introducer needle subassembly assembled from the top with a plastic tube, and FIG. 7 is a view of another introducer needle subassembly assembled from the side without a plastic tube, of the insertion device of FIG. 1 according to an embodiment of the present invention. The introducer needle subassembly used in the following description of FIG. 6 is assembled by gluing or press-fitting a tube 220 to the non-patient end of a cannula or introducer needle 222, then positioning the introducer needle through an introducer needle hub 224 and snapping it into place using any number of grooves, slots or detents 226 provided on the upper surface of the introducer needle hub 224. The introducer needle 222 can be a hollow 24G needle or cannula manufactured using 304 stainless steel, and the introducer needle hub 224 can be manufactured using PETG, although the embodiments are not limited thereto.

[0028] An alternative embodiment of the introducer needle subassembly of FIG. 7 is assembled using an introducer needle 232 having a long proximal end 234 that connects directly to a pump or reservoir (not shown). Eliminating the flexible plastic tube in this embodiment makes the assembly of the insertion device easier and reduces the risks associated with attaching two parts, but requires a large loop on the proximal end 234 of the cannula to reduce the force required to bend the cannula during insertion and retraction.

[0029] An exemplary button subassembly is shown in FIG. 8. FIG. 8 is a view of an assembly of the button subassembly of the insertion device of FIG. 1, including the catheter / partition subassembly and the introducer needle subassembly, and FIG. 9 is a view of the completed button subassembly of the insertion device of FIG. 1 according to an embodiment of the present invention. The button subassembly is constructed by combining the catheter / partition subassembly and the introducer needle subassembly with button 200. As will be described in more detail below, once assembled, the introducer needle subassembly cannot be rotated within button 200. The catheter / partition subassembly can be rotated within button 200 and, while doing so, can be rotated from a position fixed by the introducer needle subassembly to a position released from the introducer needle subassembly.

[0030] Specifically, the button subassembly is constructed by inserting introducer needle 222 of the introducer needle subassembly through septum 206 and catheter 202 of the catheter / partition subassembly. Next, the catheter / partition subassembly is fixed to the introducer needle subassembly by rotating the catheter / partition subassembly up to 20 degrees or more, locking a detent or tooth 238 on release collar 208 into a groove or slot 240 on the upper surface of introducer needle hub 224, which couples introducer needle hub 224 and the catheter / partition subassembly. In this position, tooth 238 is locked onto the upper portion of introducer needle hub 224 such that when button 200 is depressed, introducer needle hub 224 also moves downward. Thereby, introducer needle 222 and catheter 202 are moved simultaneously for insertion into the skin surface (not shown) of the user.

[0031] Next, the button subassembly is completed by snapping the release collar 208 into the button 200 to secure the introducer needle subassembly and the catheter / septum subassembly in place. To do so, the button 200 includes a detent 212 on a deflectable arm 214, as shown in FIG. 9, that can deflect between them and then capture the lower end of the release collar 208. A slot 216 is provided in the button 200 between the deflectable arms 214 to allow linear travel of the introducer needle hub 224 relative to the button 200, but prohibits rotational movement of the introducer needle hub relative to the button 200. The slot 216 in the button 200 also allows rotational movement of the radial operating pin 218 of the release collar 208 relative to the button 200, as will be described in more detail below. In an exemplary embodiment, a substantially cylindrical pin 218 is shown on the outer periphery of the release collar 208. However, in this or other embodiments of the present invention, any detent or projection of the release collar that can operate with a helical path can be provided as a radial operating pin.

[0032] Next, the button subassembly can be assembled with the housing top 100 and the mechanism housing 300. FIG. 10 is a view of the assembly of the button subassembly and spring into the housing of the insertion device of FIG. 1, showing the use of a temporary protective tube over the catheter, and FIG. 11 is a view of a partially complete assembly of the button subassembly and spring into the housing of the insertion device of FIG. 1. FIG. 12 is a view of the completed assembly of the insertion device of FIG. 1, with the base omitted for purposes of illustration, according to an embodiment of the present invention.

[0033] To complete the assembly, button 200 and its assembly are slidably assembled with a protrusion 106 extending from the inner surface of the upper housing 100 as shown in more detail in FIG. 13. FIG. 13 is a cross-sectional view of the fully assembled insertion device of FIG. 1 in a pre-operational state according to an embodiment of the present invention. The button lock arm 112 of the upper housing 100 holds the button sub-assembly in place during the next assembly step of placing the mechanism housing 300 within the upper housing 100, thereby capturing the other sub-assemblies therein.

[0034] During placement of the mechanism housing 300 within the upper housing 100, a piece of the temporary tube 228 is placed over the catheter 202 and the introducer needle 222 therein to protect the needle tip and guide the catheter through the outlet hole of the mechanism housing 300 during assembly. The retraction spring 230 is press-fitted into the introducer needle hub 224 as shown in FIG. 11, and the button sub-assembly is inserted through the hole 104 of the upper housing 100. A tube or cannula 220 that connects to a reservoir or pump (not shown) is sealed to a receiving feature within the upper housing. Spring 230 may be manufactured using stainless steel, but embodiments are not limited thereto.

[0035] The mechanism housing 300 preferably comprises a central barrel 302 that slidably receives and guides the button subassembly, and two barrels 304, one on each side of the central barrel 302 that constrains the spring 230, and is composed of three cylinders, guides or barrels. During assembly, the spring 230 is captured between the boss 242 of the introducer needle hub 224 and the bottom of the barrel 304 of the mechanism housing 300. By doing so, the spring 230 exerts an expansion force between the introducer needle hub 224 and the bottom of the barrel 304 of the mechanism housing 300. In an exemplary embodiment, a plurality of springs 230 and adjacent barrels 304 are shown. However, in this or other embodiments of the present invention, a single spring and adjacent barrel may be provided in substantially the same manner, and the unused adjacent barrels may be left empty or completely omitted. Further, a single spring may be provided on the button top, may be extended during insertion, and upon completion, retracts to its natural state, thereby retracting the introducer needle from the catheter.

[0036] The rounded boss 242 has a diameter and length for centering and aligning the spring 230 during operation. The spring 230 can be partially preloaded during the assembly of the insertion device, and the mechanism housing 300 can be laser welded or adhered to the upper housing 100. Then, the bottom or base 102 can be added. By doing so, as the final assembly step, the fully completed insertion mechanism subassembly can be placed on the base 102 along with all of the other components. Having the completed insertion mechanism subassembly makes it possible to facilitate handling during production rather than capturing all of the parts between the upper and lower housings. In an exemplary manufacturing, the mechanism housing 300 is attached to the upper housing 100 using a snap or adhesive (not shown) that holds the mechanism together. In two other exemplary embodiments described below with respect to FIGS. 25 and 26, a similar subassembly concept is used to make the assembly manageable, but the subassembly is an independent unit in one embodiment and part of the base in the other embodiment.

[0037] In each embodiment, after final assembly, the insertion device is hermetically sealed from the rest of the device. That is, the mechanism housing 300, which allows water from a shower or swimming to freely enter through the catheter exit hole or through the button hole in the housing top, is sealed in a laser welding or adhesion step, thereby protecting the remaining contents of the device housing 100, such as the contents of the electronic / pump compartment of the device.

[0038] FIG. 13 is a cross-sectional view of the fully assembled insertion device of FIG. 1, and FIG. 14 is another cross-sectional view perpendicular to the view of FIG. 13 of the fully assembled insertion device of FIG. 1 in the pre-operational state according to an embodiment of the present invention. As shown in FIG. 13, one or more breakable ribs 236 on the activation button 200 are captured by a step detent 110 within the upper housing 100 to hold the button 200 in the pre-operational position. A safety tab (not shown) can also be placed within the button slot, which can prevent the device from accidentally activating during shipment and handling of the device when it is removed from the package. The safety tab is removed immediately prior to insertion.

[0039] To activate the device, the user presses the button 200 into the upper housing 100. When the ribs 236 are damaged or exceed a deformation force threshold, the three ribs 236 yield, the button 200 suddenly moves downward, inserting the introducer needle 222 and the catheter 202 and loading the retraction spring 230. The spring 230 can be partially pre-loaded during assembly of the insertion device. The minimum break force of the breakable ribs 236 ensures that the user presses hard enough to fully insert the catheter. Partial activation results in the catheter not being fully inserted, the introducer needle not retracting, and the catheter not being locked in the post-activation position.

[0040] The release from the rib 236 of the button 200 is configured to occur when a desired amount of actuating force is applied to the button 200. Since the button 200 is releasably held in the upper and extended position by the engagement between the rib 236 and the step return stop 110, the force applied to the button 200 by the user steadily increases for a period of time before release. When suddenly released, the force on the button 200 reaches the desired value, and thus the button 200 is accelerated downward due to the sudden freedom of movement and the desired force applied to and then maintained on the button upon release. Such a release ensures that a desired amount of downward force, speed, smoothness, and angle are being applied by the user. Such actuation substantially eliminates variations in the applied user force, speed, smoothness, and its angle, reducing insertion failure and / or discomfort to the user.

[0041] After the release of the button 200, the button subassembly and the components therein begin to move through the mechanism housing 300. FIG. 15 shows a view of the insertion device at the start of such an insertion. FIG. 15 is a cross-sectional view of the fully assembled insertion device of FIG. 1 in an intermediate operating state, according to an embodiment of the present invention.

[0042] FIG. 15 also shows one of two teeth 238 on release collar 208 that couples introducer needle hub 224 to the catheter / septum subassembly. At this position, tooth 238 is locked over the top of introducer needle hub 224 such that when button 200 is depressed, introducer needle hub 224 also moves downward. When button 200 is depressed, introducer needle hub 224 likewise moves downward, which results in introducer needle 222 and catheter 202 being simultaneously inserted into the user's skin surface (not shown) and introducer needle hub 224 compressing spring 230. To create an insertion device having a small footprint, each of springs 230 has a small diameter relative to its compressed length, which would cause the springs to buckle during compression if unsupported. Boss 242 on introducer needle hub 224 translates through the center of spring 230 during compression to prevent spring 230 from buckling. In an exemplary embodiment, spring 230 is compressed and exerts an expanding force to retract the introducer needle hub and introducer needle. However, in this or other embodiments of the invention, one or more extension springs may be used to exert a retracting force to retract the introducer needle hub and introducer needle.

[0043] As described above, the catheter / wall subassembly of FIG. 5 is attached to the button 200 and the introducer needle hub 224, but is free to rotate up to 20 degrees about the primary axis. In this case, the primary axis is defined as the axis extending along the geometric center of the insertion needle 222. The slot 216 is provided in the button 200 and allows linear movement of the introducer needle hub 224 relative to the button 200, but prohibits rotational movement of the introducer needle hub relative to the button 200. The slot 216 in the button 200 also allows rotational movement of the radial operating pin 218 of the release collar 208 relative to the button 200. The angle of this rotation is controlled by the radial operating pin 218 extending from the release collar 208. During insertion, i.e., during downward movement of the button subassembly, the radial operating pin 218 moves within a helical path 400 created by the combined features of the upper housing 100 and the mechanism housing 300. During such movement, the radial operating pin 218 of the release collar 208 rotates the release collar 208, ultimately releasing the introducer needle subassembly from the catheter / wall subassembly. The surface 108 within the upper housing 100 and the surface 308 within the mechanism housing 300 that create the helical path 400 are split between the two parts, so that both parts can be molded without sliding. That is, by using the joining of two separately molded parts to create the helical path 400, a single part having a molded slide or path therein is not required, greatly simplifying the manufacture of the insertion device. FIGS. 17 and 18 show the surface 108 within the upper housing 100 and the surface 308 within the mechanism housing 300 that create the helical path 400 when assembled.

[0044] FIG. 17 is a bottom view of the upper housing 100 of the insertion device of FIG. 1 showing a part of the road surface, and FIG. 18 is a view of the mechanism housing 300 of the insertion device of FIG. 1 showing the remaining part of the road surface of the radial operating pin 218 according to an embodiment of the present invention. As shown in FIG. 17, the protrusion 106 of the upper housing 100 into which the button sub-assembly is slidably disposed includes an edge that may have a similarly curved, contoured, or otherwise configured shape 108, which, when assembled with the mechanism housing 300, forms half, a side, or a part of the spiral path 400. As shown in FIG. 18, the inner diameter or chamber surface of the mechanism housing 300 into which the button sub-assembly is slidably disposed may have a curved, contoured, or otherwise configured shape 308 that also forms half, a side, or a part of the spiral path 400 when assembled with the upper housing 100. When the upper housing 100 and the mechanism housing 300 are assembled, the elements 108 and 308 form the spiral path 400. The path is spiral such that it guides the rotational movement of the release collar 208 relative to the button 200 by guiding the radial operating pin 218 within the button 200 when the button 200 and the release collar 208 move in a linear direction.

[0045] As described above, the slot 216 provided in the button 200 enables the movement of the radial operating pin 218 of the release collar 208. Further, the catheter / partition sub-assembly of FIG. 5 is attached to the button 200 and the introducer needle hub 224 and is free to rotate up to 20 degrees about the primary axis. Such a 20-degree rotation enables the movement of the radial operating pin 218 of the release collar 208 in the helical path 400. When the button 200 is depressed, the release collar 208 and the radial operating pin 218 of the release collar 208 also move downward through the stationary upper housing 100 and the mechanism housing 300. Accordingly, the radial operating pin 218 of the release collar 208 slidably disposed in the helical path 400 rotates the release collar when moved downward by the button 200 through the stationary upper housing 100 and the mechanism housing 300.

[0046] In the pre-operated state, the angle of the radial operating pin 218 is constrained in a direction in which the teeth 238 of the release collar 208 are fully engaged with the introducer needle hub 224 therein. While the button 200 moves between the pre-operated state and the post-operated state, the radial operating pin 218 of the release collar 208 rotates the release collar 208 when moved through the helical path 400 of the stationary upper housing 100 and the mechanism housing 300.

[0047] In the post-operated state, the radial operating pin 218 is rotated up to 20 degrees, which disengages the introducer needle hub 224 from the teeth 238 of the release collar 208, frees the introducer needle hub 224 from the release collar 208, and allows it to be retracted by the compression spring 230. The release collar 208 and other elements of the catheter / partition sub-assembly remain in the lower insertion position.

[0048] FIG. 19 shows the insertion device during the insertion of the introducer needle 222 and the catheter 202 and at a point just before the introducer needle hub 224 is released by the radial operating pin 218 of the release collar 208 for retraction. The radial operating pin 218 and the release collar 208 rotate almost completely by engaging the helical path 400, and at the end of the rotation by the helical path 400, the teeth 238 on the release collar 208 become free to move from the detent 240 of the introducer needle hub 224, releasing the introducer needle hub 224 so that it can be pushed up and retracted by the spring 230. That is, when the radial operating pin 218 and the release collar 208 are rotated by engagement with the helical path 400, the teeth 238 on the release collar 208 rotate simultaneously until they are free from the detent 240 of the introducer needle hub 224. At this point, the release collar 208 held by the button 200 is no longer fixed to the introducer needle hub 224, and the spring 230 pushes the introducer needle hub 224 and the introducer needle 222 upward into the retracted position, leaving the catheter / separator subassembly in the lower insertion position. The button 200 is locked in the lower position, thereby holding the catheter / separator subassembly in the lower insertion position. The locking arm 112 protruding from the upper housing 100 that holds the button subassembly in place during assembly may also be configured to lock the button subassembly in a position that maintains the catheter within the skin and snap into the detent 244 within the button 200 in the post-operative state, as shown in FIG. 22.

[0049] Figure 20 shows the insertion device at the moment of just complete insertion of the introducer needle 222 and the catheter 20. As shown in FIGS. 21 and 23, the retraction spring 230 is fully compressed, and the radial operating pin 218 and the release collar 208 are rotated to the extent necessary to disengage the teeth 238 of the release collar 208 from the introducer needle hub 224 to release the introducer needle hub 224 for retraction. FIGS. 21 and 23 show the insertion device in the post - actuation state. At this point, the release collar 208 held downward by the button 200 is no longer fixed to the introducer needle hub 224, and the spring 230 pushes the introducer needle hub 224 and the introducer needle 222 upward to the retracted position, leaving the catheter / partition sub - assembly in the lower insertion position.

[0050] The introducer needle 222 retracts further into the housing from its pre - actuation state position to ensure shielding of the needle stick and protect the catheter from damage. The tip of the introducer needle 222 remains sealed by the partition 206 within the fluid path to form an uninterrupted fluid path with the catheter 202. In this or other embodiments, the tip or distal portion of the introducer needle 222 remains within the catheter 202, sealed by the partition 206 to form a fluid path continuous with the catheter 202.

[0051] In an exemplary embodiment, by manual insertion of the introducer needle and catheter, the insertion device is smaller, simpler, and less expensive than an insertion device employing spring - assisted insertion. Other patch pump plastic catheter insertion mechanisms use a large insertion spring relative to the retraction spring because the insertion force is large relative to the retraction force. A fully integrated spring - assisted insertion also requires angled insertion of a low - profile device, which increases the stroke and significantly increases the wound and the size of the mechanism. The insertion spring serves no purpose after insertion and simply occupies space within the device where size is one of the most important user requirements of the product.

[0052] In an exemplary embodiment, the double retraction spring configuration also allows for a very small size. One barrel of the insertion device housing guides the button and catheter, and the adjacent barrel houses two retraction springs. Having the springs in separate barrels and being directed by bosses on the introducer needle hub allows for springs that are much smaller than a single barrel configuration where the spring is coaxial with the catheter. A single coaxial spring creates access to the button assembly because the spring design limitations require the spring to extend from approximately the bottom to the top of the housing. When access is required for features such as a lock arm and the features are implemented inside the spring, the entire mechanism has to be enlarged to accommodate them, increasing the footprint of the mechanism. Passively locking the catheter down and retracting the introducer needle creates the simplest possible manual insertion user interface for a manual insertion mechanism that is pushing a single button.

[0053] As described above, the retraction spring 230 is minimally loaded prior to use to ensure that the introducer needle 222 fully retracts into the device. The spring 230 is further loaded during insertion. Providing the insertion device with a minimally loaded spring rather than a fully loaded spring reduces the risks associated with sterilization and storage of the loaded spring and simplifies the design.

[0054] To operate the insertion device, the user applies the insertion device to the skin surface using an adhesive on the base 102 of the device. Next, the user manually presses the protruding button 200 until the rib 236 is damaged or deformed. The button 200 can now move freely suddenly and is rapidly pushed into the upper housing 100, serving to push the plastic catheter 202 and the introducer needle 222 to insert into the user's skin surface. When the button 200 is being pressed, the release collar 208 is rotated by the radial operating pin 218 of the release collar 208 that moves through the spiral path 400. The release collar 208 is rotated to the extent required to disconnect the release collar 208 from the introducer needle hub 224, and the introducer needle hub 224 and the introducer needle 222 are then retracted to a retracted position beyond the original needle position to ensure needle shielding. Here, the plastic catheter 202 disconnected from the introducer needle 222 is left in the lower insertion position. The button 200 is automatically locked in the lower position at the same height as the upper part of the housing, which also locks the catheter at the desired depth in the subcutaneous layer. A sensor (not shown) can be provided to detect the post - activation state and advise other electronic devices (not shown) that the catheter has been properly inserted, which enables the patient to inject a drug. Next, a pump or reservoir injects the drug through the introducer needle into the catheter and from there into the patient's subcutaneous layer.

[0055] In the above - exemplified embodiment, the insertion mechanism can be created as a sub - assembly within the upper housing 100. This allows for easy handling of the insertion mechanism during production, and other subsystems can be assembled in that way. Alternatively, the insertion mechanism can be created as a sub - assembly separate from the upper housing 100 or the base 102, as shown in FIG. 25, or as a sub - assembly within the base 102, as shown in FIG. 26.

[0056] In FIG. 25, a substantially identical completed button sub-assembly 250 as described with respect to FIG. 9 is secured within a substantially identical mechanism housing 350 as described with respect to FIG. 4, using, for example, a snap or detent 252. In this case, the insertion mechanism is created as a sub-assembly separate from the upper housing 100 or the base 102. Once completed, the insertion mechanism of FIG. 25 can then be assembled with one or more of the upper housing 100 and the base 102.

[0057] In FIG. 26, a substantially identical completed button sub-assembly 260 as described with respect to FIG. 9 is secured within a substantially identical mechanism housing 360 as described with respect to FIG. 4. In this case, the insertion mechanism is created as a sub-assembly within the base 102. Further, in each of the embodiments of FIGS. 25 and 26, surfaces creating a helical path as described above with respect to FIGS. 17 and 18 can be provided within the button sub-assembly 250 and the mechanism housing 350, and the button sub-assembly 260, the mechanism housing 360 and / or the base 102 such that the surface can again be split into two parts, with the result that both parts can be molded without sliding.

[0058] In the above exemplary embodiment, the rib 236 determines the minimum insertion force to initiate the operation of the device to ensure full operation. Alternatively, the lock arm 112 may also be configured to determine the minimum operating force. As described above, the lock arm 112 projects from the upper housing and snaps into a detent within the button in the actuated state to lock the button subassembly in place and hold the catheter within the skin. FIG. 27 shows another embodiment of a lock arm 272 that includes a flange 274 on the lock arm that holds the button 270 in a pre-activation position. The contoured flange 274 of the lock arm 272 projects and captures the lower edge of the button 270 in the pre-actuated state and holds the button subassembly in place until sufficient force is applied to the button. When sufficient force is applied to the button 270, the flange 274 deflects away from the button 270. When sufficient force has been applied, the lock arm 272 curves out of the path of the inserted button 270. FIG. 28 shows the device in an intermediate state during insertion. The lock arm 272 is bent outwardly instead of interfering as shown in FIG. 28. The minimum deflection force of the lock arm 272 and the flange 274 ensures that the user presses hard enough to fully insert the catheter. Next, The lock arm 272 and the flange 274 snap into the detent 276 of the button 270 when the button reaches its lowest position where it locks the button and the catheter, as shown in FIG. 29.

[0059] In the above embodiment, the patch pump may comprise one or more of the described features. FIG. 30 is a perspective view of an exemplary embodiment of a patch pump 1 according to an exemplary embodiment of the present invention. The patch pump 1 is shown with a transparent cover for clarity and shows the various components that are assembled to form the patch pump 1. FIG. 31 is a view of the various components of the patch pump of FIG. 30 shown with a solid cover 2. The various components of the patch pump 1 may include a reservoir 4 for storing insulin, a pump 3 for pumping insulin from the reservoir 4, a power source 5 in the form of one or more batteries, an insertion mechanism 7 for inserting an insertion needle with a catheter into the skin of a user, control electronics 8 in the form of a circuit board having any communication function to an external device such as a remote controller and a computer including a smartphone, a dosing button 6 on the cover 2 for actuating insulin dosing including bolus dosing, and a base 9 to which the various components described above may be attached via a fastener 91. The patch pump 1 may also include various fluid connector lines for transferring the insulin pumped from the reservoir 4 to the injection site.

[0060] As described above, it should be understood that the insertion device mechanism is provided in various configurations. In some embodiments, the insertion device mechanism inserts a flexible catheter into the skin. In these embodiments, typically, the flexible catheter is supported by a rigid insertion needle. The insertion needle is inserted into the skin together with the flexible catheter and then retracted from the skin, leaving the flexible catheter within the skin. In other embodiments, no flexible catheter is provided and the insertion needle remains within the skin, forming part of an insulin flow path for delivering insulin until injection is complete. The insertion needles are typically hollow and, when they form part of the insulin flow path, need to be hollow. However, the insertion needles that support and then retract the flexible catheter can be solid or hollow. If the insertion needle deploys and retracts the flexible catheter but is part of the insulin flow path, the insertion needle should be hollow. However, if the insertion needle deploys and then retracts the flexible catheter but does not form part of the insulin flow path, the insertion needle can be solid or hollow. In either case, the insertion needle is preferably rigid enough to reliably penetrate the skin, but otherwise may have sufficient flexibility to provide comfort to the user.

[0061] FIG. 32 is a perspective view of an alternative design of a patch pump 1A having a flexible reservoir 4A shown without a cover. Such a configuration can further reduce the outer dimensions of the patch pump 1A by having the flexible reservoir 4A fill the void within the patch pump 1A. The patch pump 1A is typically illustrated using a conventional cannula insertion device 7A that inserts the cannula at an acute angle of less than 90 degrees at the surface of the user's skin. The patch pump 1A further comprises a power source 5A in the form of a battery, a measurement subsystem 41 that monitors the volume of insulin and includes low volume detection capabilities, control electronics 8A for controlling the components of the device, and a reservoir filling port 43 for receiving a refill syringe 45 for filling the reservoir 4A.

[0062] FIG. 33 is a diagram of the patch pump fluid architecture and metering subsystem of the patch pump 1A of FIG. 32. The power storage subsystem for the patch pump 1A includes a battery 5A. The control electronics 8A of the patch pump 1A may include a microcontroller 81, sensing electronics 82, pump and valve controller 83, sensing electronics 85, and deployment electronics 87 that control the operation of the patch pump 1A. The patch pump 1A includes a fluid subsystem that may include a reservoir 4A, a volume sensor 48 for the reservoir 4A, and a reservoir filling port 43 for receiving a filling syringe 45 to fill the reservoir 4A. The fluidics subsystem may include a metering system that includes a pump and valve actuator 411 and an integrated pump and valve mechanism 413. The fluidics subsystem may further include an occlusion sensor 49, a deployment actuator 7, and a cannula 47 for insertion into an injection site on the skin of a user. The architectures of the patch pumps of FIGS. 30 and 31 are the same as or similar to those shown in FIG. 33.

[0063] Another exemplary embodiment of a cannula insertion device is shown in FIG. 34. FIG. 34 is a perspective view of this embodiment of the cannula insertion device, and FIG. 35 is an exploded view showing the components of the embodiment shown in FIG. 34. The components of the cannula insertion device shown herein include a housing 3401, a return spring 3402, a catheter hub 3403, a cannula 3404, an engagement and release clip 3405, a septum and wedge 3406, a needle hub 3407, and a button 3408. As shown, the needle hub 3407 preferably surrounds the housing 3401 and includes an opening that allows the button 3408 to slide relative to the needle hub 3407.

[0064] The needle hub 3407 engages the rigid insertion needle 3409 and is biased upward by a return spring 3402. FIGS. 36A and 36B show a firing arm 3410 incorporated in the housing 3401. The housing 3401 preferably includes at least one, preferably two, firing arms 3410 located on opposite sides of the housing 3401. As shown in FIG. 36B, the firing arm 3410 is substantially rigid but can flex, and in its initial configuration, prevents the button 3408 from moving downward until sufficient force is applied to the button to overcome the rigidity of the firing arm 3410. Thus, when sufficient force is applied to the button 3408, the firing arm 3410 flexes out of the way, allowing the button to slide within the housing 3401. The housing material, the shape and length of the firing arm 3410, and the shape of the distal face of the button 3408 are configured such that the force required to overcome the resistance of the firing arm 3410 is sufficient for the insertion needle to be fully inserted by the person pressing the button 3408.

[0065] FIG. 37 shows the force profile for the button 3408. As shown, the force applied to the button rapidly increases until it reaches the firing snap peak. This is when the button overcomes the resistance of the firing arm. Next, the force rapidly decreases from the firing snap peak towards zero force and then gradually increases by the energy applied to the return spring 3402. Finally, when the button is fully inserted, the engagement and release clip releases the needle hub 3407 and releases the return spring, reducing the force on the button 3408 to nearly zero.

[0066] FIG. 38 is a cutaway view showing the engagement and release clip 3405 in its initial configuration. The engagement and release clip 3405 is housed within the housing and couples the catheter hub 3403 to the needle hub 3407. FIGS. 39A and 39B show the function of the engagement and release clip 3405 in more detail. FIG. 39A shows the engagement and release clip 3405 before the button 3408 is pressed. As shown in FIG. 39A, the engagement and release clip 3405 prevents the needle hub 3407 from separating from the catheter hub 3403. When the button 3408 is pushed far enough, the engagement and release clip 3405 reaches the distal portion of the housing 3401, and a pair of release windows 3411 allows the engagement and release clip 3405 to return to its relaxed position, thereby releasing the needle hub 3407 from the catheter hub 3403. In the relaxed position, engagement of the arms of the clip 3405 within the release windows 3411 prevents the engagement and release clip 3405 from moving in the proximal direction. Thus, the engagement and release clip 3405 serves the dual purpose of releasing the needle hub and at the same time holding the catheter hub in the inserted position.

[0067] FIG. 40A shows the engagement and release clip 3405 in its relaxed state, and FIG. 40B shows the engagement and release clip 3405 in its tensioned state, which is the configuration of the clip 3415 before it is moved towards the release window 3411 while it is attached inside the housing 3401. In this configuration, the arms 3412 of the engagement and release clip 3405 press against the inner surface of the housing 3401 outwardly. The engagement and release clip 3405 also preferably includes a connecting member 3413 that connects the arms 3412 to each other, and an opening 3414 that allows the insertion needle 3409 to move relative to the clip and inside the opening 3414.

[0068] Figures 41A - 41D show alternative embodiments of the engagement and release clip 3405. Figure 41A shows the engagement and release clip 3405 in its released state, and Figure 41B shows the relative profile of one arm of the engagement and release clip 3405 comparing the relaxed state configuration to the compressed state. Figures 41C and 41D show alternative configurations of the arms of the engagement and release clip 3405, as well as the relative stresses applied to different parts of the clip 3405 in its tensioned state.

[0069] Figure 42 is a cross - sectional view showing the relative positions of the septum and wedge 3406 and the attached engagement and release clip 3405 configuration, the needle hub 3407, and the catheter hub 3403 before the button 3408 is pressed.

[0070] Figure 43 shows the side profile of one arm 3412 of the engagement and release clip 3405. This figure also shows the locations where the catheter hub and the inner housing contact the clip 3405, as well as the tension and the opening component of the force applied by the clip arm 3412 at the contact location relative to the needle hub 3407.

[0071] Figure 44 is a perspective view from the outside of the housing 3401 showing the position of the engagement and release clip 3405 when the button is fully depressed and the clip 3405 has reached the window 3411. The window 3411 allows the clip 3405 to return to its relaxed state, thereby releasing the needle hub 3407. Figure 45 is another perspective view showing the configuration of the engagement and release clip 3405, the needle hub 3407, and the window 3411 at the exact moment when the clip 3405 first reaches the window 3411.

[0072] Figure 46 shows another aspect of this embodiment of the insertion mechanism. In some versions, the button 3408 includes a translucent or transparent window 3414 that allows the needle hub 3407 to be visible to the user to confirm that the insertion needle 3409 has been properly retracted.

[0073] Although only some exemplary embodiments of the present invention have been described in detail above, those skilled in the art will readily understand that many modifications are possible in the exemplary embodiments without substantially departing from the novel teachings and advantages of the present invention. Accordingly, all such modifications are intended to be included within the scope of the appended claims and their equivalents.

Claims

1. a housing having at least one access window in a distal portion of the housing; A flexible launch arm; a button slidable within the housing from an initial proximal position to an inserted distal position; a catheter hub secured to the catheter; a needle hub secured to an insertion needle, the insertion needle being inserted into the catheter in an initial configuration; an engagement and release clip that is larger than the interior of the housing in a relaxed state and that is compressed within the interior of the housing and that engages the catheter hub with the needle hub in the compressed state; a return spring that biases the needle hub in the proximal direction and that is compressed when the button moves distally; An insertion mechanism comprising: the firing arm resists movement of the button in a distal direction until a predetermined force is applied to the button, causing the firing arm to flex and release the button; the engagement and release clip expands toward its relaxed configuration when the button is depressed distally and the engagement and release clip aligns with the release window; The return spring moves the needle hub to a final proximal position when the engagement and release clip expands, thereby releasing the needle hub from the catheter hub.

2. The insertion mechanism of claim 1 , wherein the needle hub substantially surrounds the button and the housing.

3. The insertion mechanism of claim 1 , wherein the needle hub includes at least one opening through which the button can move.

4. The insertion mechanism of claim 1 , wherein the housing includes two firing arms on opposite sides of the housing.

5. The insertion mechanism of claim 3 , wherein the needle hub includes two openings through which the button can move.

6. The insertion mechanism of claim 1 , wherein the engagement and release clip comprises two arms joined by a connecting member.

7. The insertion system of claim 6 , wherein the connecting member comprises an opening for receiving the insertion needle and the catheter.

8. The insertion system of claim 1 , further comprising a septum and a wedge connected to the catheter, the insertion needle passing through the septum.

9. The insertion system of claim 1 , wherein the button comprises a translucent button face through which the needle hub is visible when the insertion system is successfully deployed.

10. The insertion system of claim 1 , wherein the engagement and release clip prevents the catheter hub from moving in a proximal direction when the engagement and release clip is in the relaxed state and aligned with the release window.

11. providing a housing with at least one access window in a distal portion of the housing; providing a button slidable within the housing from an initial proximal position to an inserted distal position; securing a catheter hub to a catheter; securing a needle hub to an insertion needle, the insertion needle being inserted into the catheter in an initial configuration; inserting an engagement and release clip in a compressed state inside the housing; engaging the catheter hub to the needle hub with the engagement and release clip in the compressed state; providing a return spring for biasing the needle hub in a proximal direction, the return spring being compressed when the button is moved distally; providing a firing arm that prevents movement of the button in a distal direction until a predetermined force is applied to the button, causing the firing arm to flex and release the button; allowing the engagement and release clip to expand toward its relaxed configuration when the button is pressed distally and the engagement and release clip is aligned with the release window; moving the needle hub with the return spring to a final proximal position when the engagement and release clip expands, thereby releasing the needle hub from the catheter hub; A method of inserting a catheter comprising:

12. The method of inserting a catheter according to claim 11 , further comprising the step of substantially enclosing the housing and the button with the needle hub.

13. 12. The method of inserting a catheter according to claim 11, further comprising the step of forming at least one opening through which the button can move.

14. The method of inserting a catheter according to claim 11 , further comprising forming two firing arms on opposite sides of the housing.

15. 12. The method of inserting a catheter as in claim 11, further comprising the step of forming two openings in the needle hub through which the button can move.

16. The method of inserting a catheter according to claim 11, further comprising forming the engagement and release clip with two arms joined by a connecting member.

17. a device housing including a drug reservoir connected to a catheter; a button housing having at least one release window in a distal portion of the housing; A flexible launch arm; a button slidable within the housing from an initial proximal position to an inserted distal position; a catheter hub secured to the catheter; a needle hub secured to an insertion needle, the insertion needle being inserted into the catheter in an initial configuration; an engagement and release clip that is larger than the interior of the housing in a relaxed state and that is compressed within the interior of the housing and that engages the catheter hub with the needle hub in the compressed state; biasing the needle hub in a proximal direction and compressing the button as it moves distally; A return spring, A drug injection device comprising: the firing arm prevents movement of the button in a distal direction until a predetermined force is applied to the button, causing the firing arm to flex and release the button; when the button is depressed distally and the engagement and release clip is aligned with the release window, the engagement and release clip expands toward its relaxed configuration; The return spring moves the needle hub to a final proximal position when the engagement and release clip expands, thereby releasing the needle hub from the catheter hub.

18. 18. The medication injection device of claim 17, wherein the needle hub substantially surrounds the button and the housing.

19. 18. The medication injection device of claim 17, wherein the needle hub includes at least one opening through which the button can move.

20. 18. The medication injection device of claim 17, wherein the housing comprises two firing arms on opposite sides of the housing.

21. 20. The medication injection device of claim 19, wherein the needle hub is provided with two openings through which the button can move.

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