Patent Description:
The present invention relates generally to medical infusion systems, such as an insulin infusion device or insertion device, where simple, low-profile and low-part count manual insertion device is provided with a dual retraction spring configuration for automatic introducer needle retraction. The dual retraction spring configuration is implemented using multiple barrel-shaped guides and bosses in the insertion device housing which allows for much smaller retraction springs to be used than in a single-barrel configuration.

Diabetes is a group of diseases characterized by high levels of blood glucose resulting from the inability of diabetic patients to maintain proper levels of insulin production when required. Persons with diabetes will require some form of daily insulin therapy to maintain control of their glucose levels. Diabetes can be dangerous to the affected patient if it is not treated, and it can lead to serious health complications and premature death. However, such complications can be minimized by utilizing one or more treatment options to help control the diabetes and reduce the risk of complications.

The treatment options for diabetic patients include specialized diets, oral medications and/or insulin therapy. The main goal of diabetes treatment is to control the diabetic patient's blood glucose or sugar level. However, maintaining proper diabetes management may be complicated because it has to be balanced with the activities of the diabetic patient.

For the treatment of type <NUM> diabetes, there are two principal methods of daily insulin therapy. In the first method, diabetic patients use syringes or insulin pens to self-inject insulin when needed. This method requires a needle stick for each injection, and the diabetic patient may require three to four injections daily. The syringes and insulin pens that are used to inject insulin are relatively simple to use and cost effective.

Another effective method for insulin therapy and managing diabetes is infusion therapy or infusion pump therapy in which an insulin pump is used. The insulin pump can provide continuous infusion of insulin to a diabetic patient at varying rates in order to more closely match the functions and behavior of a properly operating pancreas of a non-diabetic person that produces the required insulin, and the insulin pump can help the diabetic patient maintain his/her blood glucose level within target ranges based on the diabetic patient's individual needs.

Infusion pump therapy requires an infusion cannula, typically in the form of an infusion needle or a flexible catheter, that pierces the diabetic patient's skin and through which, infusion of insulin takes place. Infusion pump therapy offers the advantages of continuous infusion of insulin, precision dosing, and programmable delivery schedules.

In infusion therapy, insulin doses are typically administered at a basal rate and in a bolus dose. When insulin is administered at a basal rate, insulin is delivered continuously over <NUM> hours in order to maintain the diabetic patient's blood glucose levels in a consistent range between meals and rest, typically at nighttime. Insulin pumps may also be capable of programming the basal rate of insulin to vary according to the different times of the day and night. In contrast, a bolus dose is typically administered when a diabetic patient consumes a meal, and generally provides a single additional insulin injection to balance the consumed carbohydrates. Insulin pumps may be configured to enable the diabetic patient to program the volume of the bolus dose in accordance with the size or type of the meal that is consumed by the diabetic patient. In addition, insulin pumps may also be configured to enable the diabetic patient to infuse a correctional or supplemental bolus dose of insulin to compensate for a low blood glucose level at the time when the diabetic patient is calculating the bolus dose for a particular meal that is to be consumed.

Insulin pumps advantageously deliver insulin over time rather than in single injections, typically resulting in less variation within the blood glucose range that is recommended. In addition, insulin pumps may reduce the number of needle sticks which the diabetic patient must endure, and improve diabetes management to enhance the diabetic patient's quality of life.

Typically, regardless of whether a diabetic patient uses multiple direct injections (MDIs) or a pump, the diabetic patient takes fasting blood glucose medication (FBGM) upon awakening from sleep, and also tests for glucose in the blood during or after each meal to determine whether a correction dose is required. In addition, the diabetic patient may test for glucose in the blood prior to sleeping to determine whether a correction dose is required, for instance, after eating a snack before sleeping.

To facilitate infusion therapy, there are generally two types of insulin pumps, namely, conventional pumps and patch pumps. Conventional pumps require the use of a disposable component, typically referred to as an infusion set, tubing set or pump set, which conveys the insulin from a reservoir within the pump into the skin of the user. The 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 infusion needle or flexible plastic catheter extends. The base typically has an adhesive that retains the base on the skin surface during use. The cannula can be inserted onto the skin manually or with the aid of a manual or automatic insertion device. The insertion device may be a separate unit required by the user.

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

As patch pumps are designed to be a self-contained unit that is worn by the diabetic patient, it is preferable to be as small as possible so that it does not interfere with the activities of the user. Thus, in order to minimize discomfort to the user, it would be preferable to minimize the overall thickness of the patch pump. However, in order to minimize the thickness of the patch pump, its constituent parts should be reduced as much as possible. One such part is the insertion mechanism for automatically inserting the cannula into the user's skin.

In order to minimize the height of the insertion mechanism, some conventional insertion mechanisms are configured to insert the cannula at an acute angle from the surface of the skin, e.g. <NUM>-<NUM> degrees. However, it may be preferable to insert the cannula perpendicular or close to the perpendicular from the surface of the skin, since this would require the minimum length of cannula insertion. In other words, with the minimum length of cannula being inserted into the user's skin, the user can experience greater comfort and fewer complications, such as premature kinking of the cannula. But one problem with configuring the insertion mechanism to insert the cannula perpendicular to the surface of the skin is that this may increase the overall height of the insertion mechanism, and therefore of the patch pump itself.

Accordingly, a need exists for an improved insertion mechanism for use in a limited space environment, such as in the patch pump, that can cost-effectively insert a cannula vertically or close to perpendicularly into the surface of a user's skin, while minimizing or reducing its height, in order to reduce the overall height of the device the insertion mechanism is incorporated into, such as a patch pump. <CIT> describes a catheter insertion device having the features described within the preamble of claim <NUM>.

An object of the present invention is to substantially address the above and other concerns, and provide advanced, improved, and novel components and elements of an insertion device that facilitates insertion of the in-dwelling or soft catheter and retract the introducer needle, while reducing the number of components required for the construction and use of the insertion device.

Another object of the present invention is to provide a manual insertion device with at least automatic introducer needle retraction, such that the part count of the exemplary embodiments is lowered and which serves to keep part production costs low and simplify device assembly. 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 pushing the button.

Another object of the present invention is to provide a manual insertion device with at least automatic introducer needle retraction using a dual retraction spring configuration that is implemented using multiple barrel-shaped guides and bosses in the insertion device housing which allows for much smaller retraction springs to be used, such that the device is smaller and more compact.

Another object of the present invention is to provide a manual insertion device with at least automatic introducer needle retraction and activation button locking to provide needle shielding and maintain insertion of the catheter.

These and other objects are substantially achieved by providing an insertion device having the features defined within claim <NUM>. Preferred embodiments are defined by the features of the dependent claims.

Additional and/or other aspects and advantages of the present invention will be set for in the description that follows, or will be apparent from the description, or may be learned by the practice of the invention. The present invention may comprise a method or apparatus or system having one or more of the above aspects, and/or one or more of the features and combinations thereof. The present invention may comprise one or more of the features and/or combinations of the above aspects as recited, for example, in the attached claims.

The various objects, advantages and novel features of the exemplary embodiments of the present invention will be more readily appreciated from the following detailed description when read in conjunction with the appended drawings, in which:.

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

The exemplary embodiments of the present invention described below provide novel means of providing one or more infusion device elements that are configured to insert catheter up to <NUM> into a skin surface, but embodiments are not limited thereto. The insertion device is configured to perform a manual insertion of the catheter which allows the insertion device to be smaller, simpler and cheaper than automatic or springassisted insertion devices.

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 allows for 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 a button and catheter, and adjacent barrels house retraction springs, one on each side of the button and catheter. Having the springs in separate barrels allows for much smaller springs than a single-barrel configuration in which the spring is coaxial with the catheter. A single coaxial spring creates access to the button assembly since spring design limitations require the spring to extend nearly from the bottom of the housing to the top. Access is required for features like the locking arm and if the features are implemented inside the spring, the entire mechanism must grow to accommodate them increasing the mechanism foot print.

<FIG> show the insertion device before use and <FIG> shows the device after deployment of the cannula. As shown in <FIG>, the insertion device includes a top housing <NUM> and a base <NUM>. The top housing <NUM> is shown having an opening <NUM> through a top surface from which a user-accessible, and user-acutatable button <NUM> slidably extends. The content of the insertion device, including the mechanism housing <NUM>, is shown in greater detail in <FIG>. The top housing <NUM>, button <NUM>, and mechanism housing <NUM> can be manufactured from ABS, and the base <NUM> can be manufactured from PETG, but embodiments are not limited thereto.

As shown in <FIG>, the exemplary insertion device is assembled by stacking together a number of subassemblies which are trapped between the top housing <NUM> and the mechanism housing <NUM>. <FIG> is a view of the insertion device of <FIG> in accordance with an embodiment of the present invention. The subassemblies of <FIG> and discussed in greater detail below include a catheter/septum subassembly, an introducer needle subassembly, and a button subassembly. Other features and functions of the insertion device that are well-known to those skilled in the art are omitted from the figures and discussion for clarity.

An exemplary catheter/septum subassembly is shown in <FIG> is a sectional view of a catheter/septum subassembly of the insertion device of <FIG> in accordance with an embodiment of the present invention. As shown in <FIG>, the catheter/septum subassembly is assembled by attaching a catheter <NUM> on a metal wedge <NUM>, then inserting a septum <NUM> in the wedge and trapping it between a release collar <NUM> and a catheter wedge cap <NUM>. The septum <NUM> is radially compressed by the wedge <NUM> and axially compressed by the release collar <NUM> to create a seal between the septum <NUM> and wedge <NUM>. The catheter <NUM> can be a <NUM> plastic catheter manufactured using FEP, and the release collar <NUM> and catheter wedge cap <NUM> can be manufactured using PTEG, but embodiments are not limited thereto. The wedge <NUM> can be manufactured using <NUM> stainless steel, and the septum <NUM> can be manufactured using isoprene, but embodiments are not limited thereto.

Exemplary introducer needle subassemblies are shown in <FIG> and <FIG>. <FIG> is a view of an introducer needle subassembly, assembled from the top with plastic tubing, and <FIG> is a view of another introducer needle subassembly, assembled from the side with no plastic tubing, of the insertion device of <FIG> in accordance with an embodiment of the present invention. The introducer needle subassembly of <FIG> and used in the following discussion is assembled by gluing or press-fitting tubing <NUM> on the non-patient end of the cannula or introducer needle <NUM>, then placing the introducer needle through an introducer needle hub <NUM> and snapping it in place using any number of grooves, slots or detents <NUM> provided on a top surface of the introducer needle hub <NUM>. The introducer needle <NUM> can be a hollow, <NUM> needle or cannula manufactured using <NUM> stainless steel, and the introducer needle hub <NUM> can be manufactured using PETG, but embodiments are not limited thereto.

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

Other alternate embodiments of the introducer needle subassembly are shown in <FIG>. Such alternate introducer needle subassembly embodiments make assembly of the parts in high speed manufacture easier. <FIG> and <FIG> illustrate two introducer hub subassembly embodiments. As noted above, the introducer hub pushes the introducer needle during insertion, loads the compression springs during insertion and retracts the introducer needle after the plastic catheter is inserted <FIG> is an view of an introducer needle subassembly <NUM> of the insertion device of <FIG>, wherein the needle <NUM> is assembled from the top with plastic tubing <NUM>, and <FIG> is an view of an introducer needle subassembly <NUM> of the insertion device of <FIG>, wherein the needle <NUM> is assembled from the side with no plastic tubing.

In the embodiments of <FIG> and <FIG>, the introducer hub <NUM>, <NUM> is small in order to keep the insertion mechanism small, which presents challenges in molding the part and assembling the introducer needle <NUM>, <NUM>. Standard straight needle cannulation and gluing processes are not possible due to the size limitations, so the needle <NUM>, <NUM> must include a bend and be attached to the introducer hub <NUM>, <NUM> by some method. Further, the handling and assembling such a small needle <NUM>, <NUM> can be difficult and the following assemblies are provided to simplifythe manufacturing of such subassemblies.

<FIG> show a unidirectional assembly introducer hub embodiment <NUM> that is similar to the embodiment of <FIG>. The needle <NUM> is assembled into the introducer hub <NUM> from the side. The embodiment of <FIG> assembly requires multiple complex motions of the introducer needle <NUM>; the <NUM>° bend portion of the needle <NUM> is inserted into the receiving slot <NUM> in the introducer hub <NUM> then the short arm <NUM> is rotated while bending it away from the distal end and snaped into place. The unidirectional assembly intorducer hub <NUM> of <FIG> below is assembled by translating the introducer needle <NUM> into the slot <NUM> in the introducer hub <NUM>. This single motion makes automated assembly easier. The long distal straight section of the introducer needle <NUM> is, for example, held between plates (not shown) to translate the needle <NUM> during assembly and prevent rotation. The introducer hub <NUM> can be molded using, for example, an A-B mold. The snap <NUM> in the introducer hub <NUM> that retains the introducer needle <NUM> is molded by a shut off. As shown in <FIG> and <FIG>, a front or left side structure <NUM> corresponds to one side of the mold, and a rear or right side structure <NUM> corresponds to the other side of the mold.

<FIG> show an insert molded introducer hub <NUM> with a post-processed introducer needle <NUM> bend. A straight introducer needle <NUM> is insert molded with the introducer hub <NUM> as shown in <FIG>, and a post-process fixture with a steel dowel rod <NUM> is located on an upper surface of the introducer hub <NUM> as shown in <FIG>. As shown in <FIG>, the introducer needle <NUM> is then bent over the dowel rod <NUM> and snapped into the introducer hub <NUM> using snap <NUM> to prevent the needle <NUM> from springing back. The exemplary snap geometry is for illustration purposes and the invention is mot limitede thereto. The material, location, and diameter of the dowel rod (if necessary) <NUM> is sufficient to keep the bent portion of the needle <NUM> open and to avoid crimping for fluid flow after the bend process. Then, as shown in <FIG>, the dowler fixuture or rod <NUM> is removed and the subassembly <NUM> is ready for tubing assembly.

<FIG> show a cannulated straight needle introducer hub <NUM> with an introducer needle <NUM> that is glued and bent post-process. A straight introducer needle <NUM> is cannulated using standard processes by inserting the dull end of the needle <NUM> through a chamfered hole <NUM> in the introducer hub <NUM> as shown in <FIG>. The distance from the hub to the tip can be be set using, for example, a vision system and camera or other suitable measurement syustem. As shown in <FIG>, the dull side of the needle <NUM> is then bent over a rounded feature or shoulder <NUM> on the introducer hub <NUM> and snapped into into the introducer hub <NUM> using snap <NUM> to prevent the needle <NUM> from springing back.

The radius of the rounded feature or shoulder <NUM> is sufficiently large to avoid crimping or otherwise reducing the inner diamerter of the needle <NUM> and ensure that fluid could flow through the bend in the needle <NUM>. The clearance in the introducer hub through hole <NUM> required for assembly and the spring-back from bending process, prevents the needle from meeting the tolerance for the <NUM>° bend angle after the first bend, so a second distal end bend would be required to correct the angle without the provision of the rounded feature or shoulder <NUM>. This second bend however, would release the spring force exerted by the introducer needle on the introducer hub capturing snaps caused by the spring back from the first bend. Alternately, the through hole <NUM> can be molded at an angle to the insertion direction so the needle would meet the <NUM>° bend tolerance after the first bend process which would eliminate the need for a secondary bend. However, this solution would require a more complicated mold since the through hole <NUM> mold pull direction would be different from the primary mold pull directions.

Accordingly, the exemplary embodiment provides that rounded feature or shoulder <NUM>, such that the dull side of the needle <NUM> is then bent over a rounded feature or shoulder <NUM> on the introducer hub <NUM> and snapped into into the introducer hub <NUM> using snap <NUM> to prevent the needle <NUM> from springing back. In a final assembly step, glue is then dispensed in the glue well <NUM> shown in <FIG>. The glue would secure the needle <NUM> from moving relative to the introducer hub <NUM> and catheter during insertion.

An exemplary button subassembly is shown in <FIG> is a view of the assembly of the button subassembly of the insertion device of <FIG>, including the catheter/septum subassembly and introducer needle subassembly, and <FIG> is a view of the completed button subassembly of the insertion device of <FIG> in accordance with an embodiment of the present invention. The button subassembly is built by combining the catheter/septum subassembly and introducer needle subassembly with the button <NUM>. As described in greater detail below, once assembled, the introducer needle subassembly cannot be rotated in the button <NUM>. The catheter/septum subassembly can be rotated in the button <NUM> and in doing so, can be rotated from a position secured with the introducer needle subassembly, to a position freed from the introducer needle subassembly.

Specifically, the button subassembly is built by inserting the introducer needle <NUM> of the introducer needle subassembly through the septum <NUM> and catheter <NUM> of the catheter/septum subassembly. The catheter/septum subassembly is then secured to the introducer needle subassembly by rotating the catheter/septum subassembly up to <NUM> degrees or more to lock the detents or teeth <NUM> on the release collar <NUM> into grooves or slots <NUM> on the top surface of the introducer needle hub <NUM>, which couples the introducer needle hub <NUM> and catheter/septum subassembly. In this position the teeth <NUM> are locked over the top the introducer needle hub <NUM> so as the button <NUM> is pressed down, the introducer needle hub <NUM> also moves down. This results in the introducer needle <NUM> and catheter <NUM> being moved simultaneously for insertion into a user skin surface (not shown).

The button subassembly is then completed by snapping the release collar <NUM> into the button <NUM> to secure the introducer needle subassembly and the catheter/septum subassembly in place. To do so, the button <NUM> can include detents <NUM> on deflectable arms <NUM> to deflect and then capture therebetween the lower edge of the release collar <NUM> as shown in <FIG>. Between the deflectable arms <NUM>, slots <NUM> are provided in the button <NUM> to allow linear travel of the introducer needle hub <NUM> relative to the button <NUM>, but prohibit rotational movement of the introducer needle hub relative to the button <NUM>. The slots <NUM> in the button <NUM> also allow rotational movement of the radial operation pin <NUM> of the release collar <NUM> relative to the button <NUM> as described in greater detail below. In the exemplary embodiment, a substantially cylindrical-shaped pin <NUM> is shown on an outer circumference of the release collar <NUM>. However, in this or other embodiments of the present invention, any detent or projection of the release collar which can operate with the helical pathway can be provided as the radial operation pin.

The button subassembly can then be assembled with the housing top <NUM> and mechanism housing <NUM>. <FIG> is a view of the assembly of the button subassembly and springs into the housing of the insertion device of <FIG> and illustrating the use of temporary protective tubing on the catheter, and <FIG> is a view of the partially complete assembly of the button subassembly and springs into the housing of the insertion device of <FIG>. <FIG> is a view of the completed assembly of the insertion device of <FIG> wherein the base is omitted for illustration purposes in accordance with an embodiment of the present invention.

To complete assembly, the button <NUM> and assembly thereof is slidably assembled with a projection <NUM> extending from an inner surface of the top housing <NUM> as shown in greater detail in <FIG> is a sectional view of the fully assembled insertion device of <FIG> in a pre-activation state in accordance with an embodiment of the present invention. A button lock arm <NUM> of the top housing <NUM> retains the button subassembly in place during the next assembly step which is placing the mechanism housing <NUM> into the top housing <NUM> thereby trapping the other subassemblies therein.

During the placement of the mechanism housing <NUM> into the top housing <NUM>, a piece of temporary tubing <NUM> is placed over the catheter <NUM> and introducer needle <NUM> therein to both protect the needle tip and guide the catheter through the exit hole in the mechanism housing <NUM> during assembly. Retraction springs <NUM> are press fit onto the introducer needle hub <NUM> and the button subassembly is inserted through the hole <NUM> in the top housing <NUM> as shown in <FIG>. The tubing or cannula <NUM> that connects to the reservoir or pump (not shown) is sealed in a receiving feature in the top housing. The springs <NUM> can be manufactured using stainless steel, but embodiments are not limited thereto.

The mechanism housing <NUM> is preferably comprised of three cylinders, guides or barrels, including a center barrel <NUM> that slidably receives and guides the button subassembly, and two barrels <NUM>, one on each side of the center barrel <NUM> that constrain the springs <NUM>. During assembly, the springs <NUM> are captured between bosses <NUM> of the introducer needle hub <NUM> and a bottom of the barrels <NUM> of the mechanism housing <NUM>. In doing so, the springs <NUM> exert an expansion force between the introducer needle hub <NUM> and a bottom of the barrels <NUM> of the mechanism housing <NUM>. In the exemplary embodiment, a plurality of springs <NUM> and adjacent barrels <NUM> are shown. However, in this or other embodiments of the present invention, a single spring and adjacent barrel can be provided in substantially the same manner, wherein the unused adjacent barrel can be left empty or can be omitted entirely. Still further, a single spring can be provided in the button top and extended during insertion that, upon completion, retracts to its natural state thereby retracting the introducer needle from the catheter.

The rounded, bosses <NUM> are provided with a diameter and length to center and align the springs <NUM> during operation. The springs <NUM> can be partially preloaded during assembly of the insertion device, and the mechanism housing <NUM> can be laser welded or glued to the top housing <NUM>. The bottom or base <NUM> can then be added. In doing so, the full and complete insertion mechanism subassembly can be placed onto the base <NUM> with all of the other components, as the last assembly step. Having the completed insertion mechanism subassembly allows for easy handling in production, as opposed to trapping all of the parts between the top and bottom housings. In an exemplary production, the mechanism housing <NUM> would be attached to the top housing <NUM> using snaps or adhesive (not shown) which holds together the mechanism. In yet two other exemplary embodiments described below in regard to <FIG> and <FIG>, similar subassembly concepts are used to make assembly manageable, but the subassembly is an independent unit in one embodiment and part of the base in the other.

In each embodiment, after finally assembly, the insertion device is hermetically sealed from the remainder of the device. That is, the mechanism housing <NUM> into which water from a shower or swimming is free to enter through the catheter exit hole or from the button hole in the housing top, is hermetically sealed with the laser welding or gluing step, thereby protecting the remaining content of the device housing <NUM>, such as content of the electronic/pump compartments of the device.

<FIG> is a sectional view of the fully assembled insertion device of <FIG> and <FIG> is another sectional view perpendicular to the view of <FIG> of the fully assembled insertion device of <FIG> in a pre-activation state in accordance with an embodiment of the present invention. As shown in <FIG>, one or more breakable ribs <NUM> on the activation button <NUM> are captured by step detents <NUM> in the top housing <NUM> to hold the button <NUM> in the pre-activation position. A safety tab (not shown) could also be positioned in the button slot which would prevent accidental activation during shipping and handling of the device once it is removed from the packaging. The safety tab would be removed just prior to insertion.

To activate the device, the user pushes the button <NUM> into the top housing <NUM>. Once the ribs <NUM> break or deformation force threshold is exceeded, the three ribs <NUM> yield and the button <NUM> abruptly moves downward inserting the introducer needle <NUM> and catheter <NUM>, and loading the retraction springs <NUM>. The springs <NUM> can be partially preloaded during assembly of the insertion device. The minimum break force of the breakable ribs <NUM> ensures that the user pushes hard enough to fully insert the catheter. Partial activation would result in the catheter not fully inserting, the introducer needle not retracting and the catheter not locking in the post activation position.

The release of the button <NUM> from the ribs <NUM> is configured to occur once a desired amount of activation force has been applied to the button <NUM>. Since the button <NUM> is releasably held in the up and extended position by the engagement between the ribs <NUM> and the step detents <NUM>, the force applied to the button <NUM> by the user steadily increases for some period of time prior to release. Upon sudden release, the force upon the button <NUM> has reached a desired value and therefore, the button <NUM> is accelerated downward due to the sudden freedom to travel and the desired force applied to the button at the time of release and maintained thereafter. Such release ensures that a desired amount of downward force, speed, smoothness and angle has been applied by the user. Such activation substantially eliminates variations in the user force applied, speed, smoothness and angle thereof, and reduces insertion failure and/or discomfort to the user.

After the release of the button <NUM>, the button subassembly and components therein begin to travel through the mechanism housing <NUM>. <FIG> shows a view of the insertion device at the beginning of such insertion. <FIG> is a sectional view of the fully assembled insertion device of <FIG> in an intermediate activation state in accordance with an embodiment of the present invention.

<FIG> also illustrates one of the two teeth <NUM> on the release collar <NUM> that couples the introducer needle hub <NUM> and catheter/septum subassemblies. In this position the teeth <NUM> are locked over the top the introducer needle hub <NUM> so as the button <NUM> is pressed down, the introducer needle hub <NUM> moves down as well. As the button <NUM> is pressed down, the introducer needle hub <NUM> moves down as well, which results in the introducer needle <NUM> and catheter <NUM> being simultaneously inserted into a user skin surface (not shown), and also results in the introducer needle hub <NUM> compressing the springs <NUM>. In order to create an insertion device with a small foot print, each of the springs <NUM> has a small diameter relative to the compression length which, if unsupported, would cause the springs to buckle during compression. The bosses <NUM> on the introducer needle hub <NUM> translate through the middle of the springs <NUM> during compression to prevent the springs <NUM> from buckling. In the exemplary embodiment, the springs <NUM> are compressed, and exert an expansion force to retract the introducer needle hub and introducer needle. However, in this or other embodiments of the present invention, one or more extension springs can be used, and exert a retraction force to retract the introducer needle hub and introducer needle.

As noted above, the catheter/septum subassembly of <FIG> is attached to the button <NUM> and introducer needle hub <NUM> but is free to rotate up to <NUM> degrees around the primary axis. In this case, the primary axis is defined as the axis extending along the geometric center of the insertion needle <NUM>. Slots <NUM> are provided in the button <NUM> to allow linear travel of the introducer needle hub <NUM> relative to the button <NUM>, but prohibit rotational movement of the introducer needle hub relative to the button <NUM>. The slots <NUM> in the button <NUM> also allow rotational movement of the radial operation pin <NUM> of the release collar <NUM> relative to the button <NUM>. The angle of this rotation is controlled by the radial operation pin <NUM> extending from the release collar <NUM>. During insertion, that is, downward travel of the button subassembly, the radial operation pin <NUM> travels in a helical pathway <NUM> created by the combined features in the top housing <NUM> and mechanism housing <NUM>. During such travel, the radial operation pin <NUM> of the release collar <NUM> rotates the release collar <NUM> to eventually release the introducer needle subassembly from the catheter/septum subassembly. The surfaces <NUM> in the top housing <NUM>, and <NUM> in the mechanism housing <NUM> that create the helical pathway <NUM> are divided between two parts, so that both parts can be molded without slides. That is, by creating the helical pathway <NUM> using the coupling of two separately molded parts, a single part having the slide or pathway molded therein is not required, significantly simplifying the manufacture of the insertion device. <FIG> and <FIG> show the surface <NUM> in the top housing <NUM>, and <NUM> in the mechanism housing <NUM> that create the helical pathway <NUM> when assembled.

<FIG> is an bottom view of the top housing <NUM> of the insertion device of <FIG> illustrating a portion of the pathway surface, and <FIG> is a view of the mechanism housing <NUM> of the insertion device of <FIG> illustrating the remaining portion of the pathway surface of the radial operation pin <NUM> in accordance with an embodiment of the present invention. As shown in <FIG>, the projection <NUM> of the top housing <NUM>, into which the button subassembly is slidably disposed, includes an edge that can be provided with a similar curved, contoured, or otherwise configured shape <NUM> that, upon assembly with the mechanism housing <NUM>, forms one half, side or portion of the helical pathway <NUM>. As shown in <FIG>, an inner diameter or chamber surface of the mechanism housing <NUM>, into which the button subassembly is slidably disposed, can be provided with a curved, contoured, or otherwise configured shape <NUM> that, upon assembly with the top housing <NUM>, also forms one half, side or portion of the helical pathway <NUM>. When the top housing <NUM> and mechanism housing <NUM> are assembled, the elements <NUM> and <NUM> form the helical pathway <NUM>. The pathway is helical to induce a rotational movement of the release collar <NUM> relative to the button <NUM> by guiding the radial operation pin <NUM> therein, as the button <NUM> and release collar <NUM> travel in a linear direction.

As noted above, the slots <NUM> provided in the button <NUM> allow movement of the radial operation pin <NUM> of the release collar <NUM>. Further, the catheter/septum subassembly of <FIG> is attached to the button <NUM> and introducer needle hub <NUM>, but is free to rotate up to <NUM> degrees around the primary axis. Such <NUM> degrees of rotation permits the travel of the radial operation pin <NUM> of the release collar <NUM> in the helical pathway <NUM>. As the button <NUM> is pressed down, the release collar <NUM> and radial operation pin <NUM> of the release collar <NUM> move down as well through the stationary top housing <NUM> and mechanism housing <NUM>. The radial operation pin <NUM> of the release collar <NUM> therefore, slidably disposed in the helical pathway <NUM>, rotates the release collar when moved down through the stationary top housing <NUM> and mechanism housing <NUM> by the button <NUM>.

In the pre-activation state, the radial operation pin <NUM> angle is constrained to an orientation in which the teeth <NUM> of the release collar <NUM> are fully engaged with the introducer needle hub <NUM>. During button <NUM> movement between the pre-activation state and the post-activation state, the radial operation pin <NUM> of the release collar <NUM> rotates the release collar <NUM> when moved through helical pathway <NUM> of the stationary top housing <NUM> and mechanism housing <NUM>.

In the post-activation state, the radial operation pin <NUM> has been rotated up to <NUM> degrees, which decouples the introducer needle hub <NUM> from the teeth <NUM> of the release collar <NUM>, freeing the introducer needle hub <NUM> from the release collar <NUM>, to be retracted by the compressed springs <NUM>. The release collar <NUM> and other elements of the catheter/septum subassembly are left in the down and inserted position.

<FIG> shows the insertion device during insertion of the introducer needle <NUM> and catheter <NUM> and at a point just before the introducer needle hub <NUM> is released by the radial operation pin <NUM> of the release collar <NUM> for retraction. The radial operation pin <NUM> and the release collar <NUM> is almost fully rotated by engagement with the helical pathway <NUM> and where, at the end of rotation by the helical pathway <NUM>, the teeth <NUM> on the release collar <NUM> are about to move free of the detents <NUM> of the introducer needle hub <NUM> and release the introducer needle hub <NUM> so it can be pushed up and retracted by the springs <NUM>. That is, as the radial operation pin <NUM> and the release collar <NUM> are rotated by engagement with the helical pathway <NUM>, the teeth <NUM> on the release collar <NUM> simultaneous rotate until free of the detents <NUM> of the introducer needle hub <NUM>. At this point, the release collar <NUM> being held down by the button <NUM>, is no longer secured to the introducer needle hub <NUM>, and the springs <NUM> force the introducer needle hub <NUM> and introducer needle <NUM> upward and into the retracted position, leaving the catheter/septum subassembly in the down and inserted position. The button <NUM> is locked in the down position, thereby holding the catheter/septum subassembly in the down and inserted position. The lock arm <NUM> that protrudes from the top housing <NUM> that retains the button subassembly in place during assembly can also be configured to snap into a detent <NUM> in the button <NUM> in the post-activation state locking the button subassembly in place keeping the catheter in the skin as shown in <FIG>.

<FIG> shows the insertion device just at full insertion of the introducer needle <NUM> and catheter <NUM>. The retraction springs <NUM> are fully compressed and the radial operation pin <NUM> and release collar <NUM> have been rotated to an extent required for decoupling the teeth <NUM> of the release collar <NUM> from the introducer needle hub <NUM> to release the introducer needle hub <NUM> for retraction as shown in <FIG> and <FIG>. <FIG> and <FIG> show the insertion device in a post-activation state. At this point, the release collar <NUM> being held down by the button <NUM>, is no longer secured to the introducer needle hub <NUM>, and the springs <NUM> force the introducer needle hub <NUM> and introducer needle <NUM> upward and into the retracted position, leaving the catheter/septum subassembly in the down and inserted position.

The introducer needle <NUM> retracts farther into the housing than its pre-activation state position to ensure needle stick shielding and to protect the catheter from damage. The tip of the introducer needle <NUM> remains sealed by the septum <NUM> in the fluid path to form an uninterrupted fluid path with the catheter <NUM>. In this or other embodiments, the tip or distal portion of the introducer needle <NUM> remains within the catheter <NUM> and sealed by the septum <NUM> to form an uninterrupted fluid path with the catheter <NUM>.

In the exemplary embodiments, manual insertion of the introducer needle and catheter allows the insertion device to be smaller, simpler and cheaper than insertion devices employing spring assisted insertion. Other patch pump plastic catheter insertion mechanisms use insertion springs which are large relative to the retraction spring because the insertion force is large relative to the retraction force. Fully integrated, spring assisted insertion also requires angled insertion for a low profile device which increases the stroke and greatly increases the wound and mechanism size. The insertion spring serves no purpose after insertion, but simply takes up room in the device wherein size is one of the most important user requirements for the product.

In the exemplary embodiments, the dual 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 barrels house the two retraction springs. Having the springs in separate barrels and directed by bosses on the introducer needle hub allows for much smaller springs than a single barrel configuration in which the spring is coaxial with the catheter. A single coaxial spring creates access to the button assembly since spring design limitations require the spring to extend nearly from the bottom of the housing to the top. Access is required for features like the locking arm and if the features are implemented inside the spring, the entire mechanism must grow to accommodate them increasing the mechanism foot print. Passively locking the catheter down and retracting the introducer needle creates the simplest possible manual insertion user interface for a manual insertion mechanism which is a single button push.

As noted, the retraction springs <NUM> are minimally loaded before use to ensure that the introducer needle <NUM> retracts into the device completely. The springs <NUM> load further during insertion. Providing minimally loaded springs and not fully loaded springs in the insertion device, reduces the risk associated with sterilizing and storing loaded springs and simplifies the design.

To operate the insertion device, the user applies the insertion device to a skin surface using an adhesive upon the base <NUM> of the device. The user then manually pushes the protruding button <NUM> until breaking or deforming the ribs <NUM>. The button <NUM>, now suddenly free to travel, is rapidly pushed into the top housing <NUM> and serves to push and insert the plastic catheter <NUM> and introducer needle <NUM> into a user skin surface. As the button <NUM> is being pushed, the release collar <NUM> is rotated by the radial operation pin <NUM> of the release collar <NUM> moving through helical pathway <NUM>. The release collar <NUM> is rotated to an extent required for decoupling the release collar <NUM> from the introducer needle hub <NUM>, and the introducer needle hub <NUM> and introducer needle <NUM> are then retracted to a retracted position, exceeding that of the original needle position to ensure needle shielding. The plastic catheter <NUM> now uncoupled from the introducer needle <NUM> is left in the down and inserted position. The button <NUM> automatically locks in the down position, flush with the top of the housing, which also locks the catheter at the desired depth in the subcutaneous layer. A sensor (not shown) can be provided to sense the post-activation state and advise other electronics (not shown) that the catheter has been inserted properly which allows the patient to infuse medicament. A pump or reservoir then infuses medicament through the introducer needle, into the catheter and out into the patient's subcutaneous layer.

To best target the desired depth, the base can include skin interface geometry to achieve and maintain a desired insertion depth, avoid skin surface tenting, and/or tension the skin surface at the insertion site. <FIG> show examples of such skin interface geometry with a catheter deployed. In the perspective view of the device <NUM>, a post <NUM> from which the catheter <NUM> extends during placement, protrudes into the skin surface (not shown) which helps prevent shallow catheter tip insertion in cases where the skin tented. The post <NUM> can extend from the base surface of the device <NUM> to any desired length, and can be rounded and/or chamfered at the distal end contacting the skin surface.

A well <NUM> can be provided surrounding the post <NUM>. The well <NUM> provides space for the skin that is displaced during insertion and helps the post <NUM> protrude into the skin surface. A wall <NUM> surrounds and defines the well <NUM>, and can extend from the base surface of the device <NUM> to any desired length and can be rounded and/or chamfered at the distal end contacting the skin surface. The round opposing cylinders <NUM> in <FIG> can be provided, or excluded from the geometry as desired.

In the above exemplary embodiment, the insertion mechanism can be created as a subassembly in the top housing <NUM>. This allows the insertion mechanism to be handled easily during production so the other sub systems can be assembled. Alternatively, the insertion mechanism can be created as a subassembly separate from the top housing <NUM> or base <NUM> as shown in <FIG>, or as a subassembly in the base <NUM> as shown in <FIG>.

In <FIG>, a completed button subassembly <NUM>, substantially the same as described in regard to <FIG>, is secured within a mechanism housing <NUM>, substantially the same as described in regard to <FIG>, using, for example, snaps or detents <NUM>. In this case, the insertion mechanism is created as a subassembly separate from the top housing <NUM> or base <NUM>. Upon completion, the insertion mechanism of <FIG> can then be assembled with one or more of the top housing <NUM> and base <NUM>.

In <FIG>, a completed button subassembly <NUM>, substantially the same as described in regard to <FIG>, is secured within a mechanism housing <NUM>, substantially the same as described in regard to <FIG>. In this case, the insertion mechanism is created as a subassembly in the base <NUM>. Further, in each embodiment of <FIG> and <FIG>, the surfaces that create the helical pathway as described above in regard to <FIG> and <FIG>, can be provided in the button subassembly <NUM> and mechanism housing <NUM>, and in the button subassembly <NUM>, mechanism housing <NUM> and/or base <NUM>, such that the surfaces can again be divided between two parts, so that both parts can be molded without slides.

In the above exemplary embodiment, the ribs <NUM> determine the minimum insertion force to start activation of the device which ensures full activation. Alternatively, the lock arm <NUM> can be configured to also determine the minimum activation force. As noted above, the lock arm <NUM> protrudes from the top housing and snaps into a detent in the button in the post-activation state locking the button subassembly in place keeping the catheter in the skin. <FIG> shows another embodiment of the lock arm <NUM> including a flange <NUM> on the lock arm that holds the button <NUM> in the pre-activation position. The contoured flange <NUM> of the lock arm <NUM> protrudes and captures a bottom edge of the button <NUM> in the pre-activation state, holding the button subassembly in place until a sufficient force is applied to the button. Once a sufficient force is applied to the button <NUM>, the flange <NUM> is deflected clear of the button <NUM>. The lock arm <NUM> bends out of the path of the insertion button <NUM> when sufficient force is applied. <FIG> shows the device in an intermediate state during insertion. The lock arm <NUM> would be bent outward instead of interfering as <FIG> depicts. The minimum deflection force of the lock arm <NUM> and flange <NUM> ensures that the user pushes hard enough to fully insert the catheter. The lock arm <NUM> and flange <NUM> then snap into the detent <NUM> in the button <NUM> when the button reaches the down most position which locks the button and catheter as shown in <FIG>.

In the above embodiments, a patch pump can be provided with one or more of the described features. <FIG> is a perspective view of an exemplary embodiment of a patch pump <NUM> according to an exemplary embodiment of the invention. The patch pump <NUM> is illustrated with a see-through cover for clarity and illustrates various components that are assembled to form the patch pump <NUM>. <FIG> is a view of the various components of the patch pump of <FIG>, illustrated with a solid cover <NUM>. The various components of the patch pump <NUM> may include: a reservoir <NUM> for storing insulin; a pump <NUM> for pumping insulin out of the reservoir <NUM>; a power source <NUM> in the form of one or more batteries; an insertion mechanism <NUM> for inserting an inserter needle with a catheter into a user's skin; control electronics <NUM> in the form of a circuit board with optional communications capabilities to outside devices such as a remote controller and computer, including a smart phone; a dose button <NUM> on the cover <NUM> for actuating an insulin dose, including a bolus dose; and a base <NUM> to which various components above may be attached via fasteners <NUM>. The patch pump <NUM> also includes various fluid connector lines that transfer insulin pumped out of the reservoir <NUM> to the infusion site.

As noted above, it should be understood that inserter mechanisms come in various configurations. In some embodiments, the inserter mechanism inserts a soft catheter into the skin. In these embodiments, typically the soft catheter is supported on a rigid insertion needle. The insertion needle is inserted into the skin along with the soft catheter, and then retracted from the skin, leaving the soft catheter in the skin. In other embodiments, a soft catheter is not provided, and the insertion needle remains in the skin and forms a portion of the insulin flow path to deliver insulin until the infusion is finished. Insertion needles are typically hollow, and need to be hollow if they form part of the insulin flow path. However, insertion needles that support a soft catheter and then retract may be solid or hollow. If the insertion needle deploys a soft catheter, and retracts but remains part of the insulin flow path, then the insertion needle should be hollow. However, if the insertion needle deploys a soft catheter and then retracts but does not form part of the insulin flow path, then the insertion needle may be solid or hollow. In either case, the insertion needle is preferably rigid enough to reliably penetrate the skin, but otherwise may be made flexible enough to provide comfort to the user.

<FIG> is a perspective view of an alternative design for a patch pump 1A having a flexible reservoir 4A, and illustrated without a cover. Such arrangement may further reduce the external dimensions of the patch pump 1A, with the flexible reservoir 4A filling voids within the patch pump 1A. The patch pump 1A is illustrated with a conventional cannula insertion device 7A that inserts the cannula, typically at an acute angle, less than <NUM> degrees, at the surface of a user's skin. The patch pump 1A further comprises: a power source 5A in the form of batteries; a metering sub-system <NUM> that monitors the volume of insulin and includes a low volume detecting ability; control electronics 8A for controlling the components of the device; and a reservoir fill port <NUM> for receiving a refill syringe <NUM> to fill the reservoir 4A.

<FIG> is a patch-pump fluidic architecture and metering sub-system diagram of the patch pump 1A of <FIG>. The power storage sub-system for the patch pump 1A includes batteries 5A. The control electronics 8A of the patch pump 1A may include a microcontroller <NUM>, sensing electronics <NUM>, pump and valve controller <NUM>, sensing electronics <NUM>, and deployment electronics <NUM> that control the actuation of the patch pump 1A. The patch pump 1A includes a fluidics sub-system that may include a reservoir 4A, volume sensor <NUM> for the reservoir 4A, a reservoir fill port <NUM> for receiving a refill syringe <NUM> to refill the reservoir 4A. The fluidics sub-system may include a metering system comprising a pump and valve actuator <NUM> and an integrated pump and valve mechanism <NUM>. The fluidics sub-system may further include an occlusion sensor, a deploy actuator, as well as the cannula <NUM> for insertion into an infusion site on the user's skin. The architecture for the patch pumps of <FIG> and <FIG> is the same or similar to that which is illustrated in <FIG>.

<FIG> illustrates another embodiment of the insertion device which is assembled by stacking together a number of subassemblies that can be contained between a top housing <NUM> and a mechanism housing <NUM>. <FIG> is an exploded view of the insertion device. The subassemblies of <FIG> include a catheter/septum subassembly, an introducer needle subassembly, and a button subassembly. Other features and functions of the insertion device that are well-known to those skilled in the art are omitted from the figures and discussion for clarity.

The catheter/septum subassembly is assembled by attaching a catheter <NUM> on a metal wedge <NUM>, then inserting a septum <NUM> in the wedge and containing it between a release collar <NUM> and a catheter wedge cap. The septum <NUM> is radially compressed by the wedge <NUM> and axially compressed by the release collar <NUM> to create a seal between the septum <NUM> and wedge <NUM>.

The introducer needle subassembly is assembled by gluing or press-fitting tubing <NUM> on the non-patient end of the cannula or introducer needle <NUM>, then placing the introducer needle through an introducer needle hub <NUM> and snapping it in place using any number of grooves, slots or detents <NUM> provided on a top surface of the introducer needle hub <NUM>.

The button subassembly is built by inserting the introducer needle <NUM> of the introducer needle subassembly through the septum <NUM> and catheter <NUM> of the catheter/septum subassembly. The introducer needle hub <NUM> and catheter/septum subassembly are coupled together. This results in the introducer needle <NUM> and catheter <NUM> being moved simultaneously for insertion into a user skin surface (not shown). The button subassembly is completed by snapping the release collar <NUM> into the button <NUM> to secure the introducer needle subassembly and the catheter/septum subassembly in place. To do so, the button <NUM> can include detents <NUM> on deflectable arms <NUM> to deflect and then capture therebetween the lower edge of the release collar <NUM>.

As illustrated in <FIG> the insertion device includes a cap <NUM> to secure the button subassembly within the mechanism housing <NUM>. Cap <NUM> may consist of, for example, an oval shape. <FIG> illustrates that cap <NUM> has a lock arm <NUM> including a flange <NUM> on the lock arm. The flange <NUM> engages an edge of button <NUM> to thereby reduce tolerance stack and hold the button <NUM> in the pre-activation position. Flange <NUM> includes, for example, a contoured shape. The contoured flange <NUM> of the lock arm <NUM> holds the button subassembly in place in the pre-activation state until a sufficient force is applied to the button see <FIG>. <FIG> shows that once a minimum velocity of the button <NUM> is reached, the flange <NUM> deflects clear of the button <NUM>. The lock arm <NUM> bends out of the path of the insertion button <NUM> when sufficient force is applied. <FIG> shows the device in an intermediate state during insertion. The lock arm <NUM> can be bent outward as shown in <FIG> and the ramp <NUM> takes up any clearance as button <NUM> is pushed downward. The minimum velocity of the lock arm <NUM> and flange <NUM> ensures that the user pushes hard enough to fully insert the catheter. As illustrated in <FIG>, flange <NUM> then snaps into the detent <NUM> in the button <NUM> when the button reaches the down most position which locks the button and catheter as shown in <FIG>. <FIG> shows the introducer needle <NUM> retracted into catheter <NUM>.

<FIG> illustrates that cap <NUM> includes a key <NUM>. Key <NUM> fits into button slot <NUM> to prevent the button from rotating and thereby preventing premature retraction. Cap <NUM> also has a cap side <NUM> as illustrated in <FIG>. Cap side <NUM> includes a track <NUM> extending substantially the length of mechanism housing <NUM> to also prevent accidental premature rotation.

<FIG> illustrates protrusions <NUM> on mechanism housing <NUM>. Housing mechanism <NUM> is retained in the housing top <NUM> by an interference fit between protrusions <NUM> and housing top <NUM>.

The insertion device of the present embodiment provides improved needle shielding and prevents needle stick hazard after use. As illustrated in <FIG> and <FIG>, in the pre-activation state, the springs <NUM> are preloaded. Also in the pre-activation state, introducer hub <NUM> and cap <NUM> abut release collar <NUM> forming a gap between cap <NUM> and introducer hub <NUM>. <FIG> shows button <NUM> extended in the pre-activation state. When button <NUM> is pressed hub <NUM> travels downward insertion needle <NUM> and cannula <NUM> also travels downward and springs <NUM> are compressed illustrated in <FIG>. <FIG> shows the insertion needle <NUM> and cannula <NUM> fully extended out of the base102. After the insertion needle <NUM> and cannula <NUM> reach the desired depth, springs <NUM> force the introducer needle hub <NUM> and introducer needle <NUM> upward into the retracted position, leaving the catheter/septum subassembly in the down and inserted position as shown in <FIG> illustrates the introducer needle <NUM> retracted farther into mechanism housing <NUM> in the retracted stated than in the activation state of <FIG> as where introducer needle hub <NUM> abuts against cap <NUM> eliminating the gap. Further retraction of the introducer needle as shown in <FIG> ensures needle stick shielding and to protects the catheter from damage.

Additional improvements of the current embodiment include bosses <NUM> on the introducer hub <NUM> having a shorter length than the length in previous embodiments. This shorter length enhances centering and alignment of the springs <NUM> with the introducer hub <NUM>. The introducer hub <NUM> also includes an extra slot <NUM> as shown in <FIG> to enhance the efficiency of molding.

To best target the desired depth, the base can include skin interface geometry to achieve and maintain a desired insertion depth, avoid skin surface tenting, and/or tension the skin surface at the insertion site. <FIG> shows an alternative example of such skin interface geometry with a catheter deployed. In the perspective view of the device <NUM>, a post <NUM> from which the catheter <NUM> extends during placement, protrudes into the skin surface (not shown) which helps prevent shallow catheter tip insertion in cases where the skin tented. The post <NUM> can extend from the base surface of the device <NUM> to any desired length, and can be rounded and/or chamfered at the distal end contacting the skin surface.

A well <NUM> can be provided surrounding the post <NUM>. The well <NUM> provides space for skin that is displaced during insertion and helps the post <NUM> protrude into the skin surface. A wall <NUM> surrounds and defines the well <NUM>, and can extend from the base surface of the device <NUM> to any desired length and can be rounded and/or chamfered at the distal end contacting the skin surface. The round opposing cylinders <NUM> in <FIG> are provided as flush with the base surface of the device <NUM> the adhesive that retains the base on the skin surface during use extends over the round opposing cylinders <NUM>, which improves functionality of the device and reduces tenting.

<FIG> illustrate an alternate release collar, septum and wedge for use in an embodiment of the present invention. Catheter/septum subassembly <NUM> comprises a release collar <NUM> that is deformed to retain a septum <NUM> and wedge <NUM>. Septum <NUM> is preferably cylindrical in shape. As best seen in <FIG>, release collar <NUM> is heat staked during manufacture to deform the inner surface <NUM> of the release collar <NUM> to form a lip <NUM> that retains the septum <NUM> and wedge <NUM> within the release collar <NUM>. This simplifies manufacturing and reduces the number of components required. Heat staking is described in further detail, for example, in <CIT> It should be appreciated that any suitable septum and wedge retention method may be used with the insertion mechanisms described herein, and the septum and wedge retention structure shown in <FIG> is merely exemplary of one such suitable structure. Any other structures of septum, wedge, and related components described herein, or suitable variations thereof are within the scope of the present invention.

<FIG> is a cross sectional view of a staking tool for heat staking the release collar shown in <FIG> above. As illustrated, a staking tool <NUM> includes a staking geometry <NUM> to deform a portion <NUM> of the inner surface <NUM> of the release collar <NUM>. The deformation forms the lip <NUM> shown in <FIG>.

Although only a few exemplary embodiments of the present invention have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of the appended claims and their equivalents. related components described herein, or suitable variations thereof are within the scope of the present invention.

Claim 1:
A catheter insertion device, comprising:
a device housing and a button (<NUM>) slidably captured therein;
a catheter/septum subassembly, rotatably captured by said button (<NUM>); and
an introducer needle subassembly, releasably secured to said catheter/septum subassembly,
wherein said catheter/septum subassembly is rotatable relative to said button (<NUM>) from a first radial position secured to said introducer needle subassembly, to a second radial position released from said introducer needle subassembly, in response to a linear movement of said button (<NUM>),
characterized in that
said button (<NUM>) moves said introducer needle subassembly from a first linear position to a second linear position to manually insert a catheter (<NUM>) without springassistance of said catheter/septum subassembly, and simultaneously rotate said catheter/septum subassembly to said second radial position, thereby releasing said introducer needle subassembly from said catheter/septum subassembly.