Patent Publication Number: US-2021162117-A1

Title: Patch pump cartridge attachment

Description:
RELATED APPLICATION 
     This application is a continuation of application Ser. No. 15/987,432 filed May 23, 2018, which is a continuation of application Ser. No. 15/158,125 filed May 18, 2016, now U.S. Pat. No. 9,993,595 issued Jun. 12, 2018, which claims the benefit of U.S. Provisional Application No. 62/163,158 filed May 18, 2015, each of which is hereby incorporated herein in its entirety by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to medical pumps for delivering medicament to a patient and, more specifically, to a user-wearable insulin patch pump for delivering insulin to a patient. 
     BACKGROUND OF THE INVENTION 
     There are many applications in academic, industrial, and medical fields that benefit from devices and methods that are capable of accurately and controllably delivering fluids, such as liquids and gases, that have a beneficial effect when administered in known and controlled quantities. Such devices and methods can be particularly useful in the medical field where treatments for many patients include the administration of a known amount of a substance at predetermined intervals. 
     One category of devices for delivering such fluids is that of pumps that have been developed for the administration of insulin and other medicaments for those suffering from both type I and type II diabetes. Some pumps configured as portable infusion devices can provide continuous subcutaneous medicament injection and/or infusion therapy for the treatment of diabetes. Such therapy may include, e.g., the regular and/or continuous injection or infusion of insulin into the skin of a person suffering from diabetes and offer an alternative to multiple daily injections of insulin by an insulin syringe or an insulin pen. Such pumps can be ambulatory/portable infusion pumps that are worn by the user and may use replaceable cartridges. Examples of such pumps and various features that can be associated with such pumps include those disclosed in U.S. Patent Application Publication No. 2013/0053816, U.S. Pat. Nos. 8,573,027, 8,986,253, U.S. Patent Application Publication No. 2013/0324928, U.S. Patent Application Publication No. 2013/0331790 and U.S. Pat. No. 8,287,495, each of which is hereby incorporated herein by reference in its entirety. 
     One type of pump that has been developed is a patch pump, or micro pump. Patch pumps are small pumps, typically ambulatory, that are carried directly on the skin under the user&#39;s clothing. Many such pumps are situated directly on the injection site such that no tubing is required to deliver the insulin or other medicament to the patient. Other patch pumps can be positioned on the user&#39;s body with a short length of tubing extending to a nearby infusion site. Patch pumps typically are at least in part disposable, meant to be worn for a day or two and then discarded for a new patch pump. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Subject matter hereof may be more completely understood in consideration of the following detailed description of various embodiments in connection with the accompanying figures, in which: 
         FIGS. 1A-1F  are views of portions of a patch pump system according to an embodiment of the present invention. 
         FIGS. 2A-2C  depict a cartridge being attached to a drive unit of a patch pump system according to an embodiment of the present invention. 
         FIGS. 3A-3D  are schematic representations of a cartridge and drive mechanism of a patch pump system according to an embodiment of the present invention. 
         FIGS. 4A-4B, 5A-5B and 6A-6B  depict alternate uses of a patch pump according to an embodiment of the present inventions. 
         FIGS. 7A-7C  depicts remote control devices for a patch pump system according to embodiments of the present invention. 
         FIG. 8  depicts a patch pump system according to an embodiment of the present invention. 
         FIGS. 9A-9D  depict a procedure for filling a cartridge of a patch pump system according to an embodiment of the present invention. 
         FIGS. 10A-10E  depict a procedure for inductively charging the battery of a patch pump system according to an embodiment of the present invention. 
         FIGS. 11A-11E  depict a procedure for inserting a cannula into the skin of a user of a patch pump system according to an embodiment of the present invention. 
         FIGS. 12A-12D  depict a procedure for inserting a cannula into the skin of a user of a patch pump system according to an embodiment of the present invention. 
         FIGS. 13A-13C  depict a patch pump according to an embodiment of the present invention. 
         FIGS. 14A-14B  depict a patch pump system according to an embodiment of the present invention. 
         FIGS. 15-16, 17A-17B, 18A-18C and 19  are schematic representations of a cartridge and drive mechanism of a patch pump system according to an embodiment of the present invention. 
     
    
    
     While various embodiments are amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the claimed inventions to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the subject matter as defined by the claims. 
     SUMMARY 
     A user-wearable patch pump system for delivery of insulin or other medicament can include a patch pump having a reusable drive unit and a replaceable and/or refillable cartridge. The cartridge can selectively attach to and be detached from the drive unit. The cartridge can initially be inserted onto the drive unit in a first orientation at an angle to the drive unit and then be rotated to align the cartridge with the drive unit and lock the cartridge in place on the drive unit to form the patch pump. 
     In some embodiments a user-wearable infusion pump system includes a pump having a disposable cartridge and a drive unit. The disposable cartridge can be configured to contain a medicament and include a cartridge housing having a front surface and a rear surface and a coupling recess defined in a bottom surface of the cartridge housing. The drive unit can be configured to cause medicament in the cartridge to be delivered to a user wearing the pump and include a drive unit housing having a front surface and a rear surface and a drive mechanism having a drive end extending from the drive unit. The coupling recess in the cartridge can be configured to be inserted onto the drive end of the drive mechanism with the cartridge in a first orientation with respect to the drive unit and the cartridge can be configured to then be rotated with respect to the drive unit in a first direction with the drive end in the coupling recess to lock the cartridge onto the drive unit in a second orientation with the front surface of the cartridge aligned generally parallel with the front surface of the drive unit. In various embodiments, the angle between the cartridge and drive unit can be between about 30 degrees and about 150 degrees, including for example, a generally perpendicular (about 90 degree angle) and about a 60 degree angle. 
     In some embodiments, the cartridge includes a pair of flanges on opposing sides of the coupling recess each adjacent a respective slot and the drive end includes a pair of threads on opposing sides of the drive end. The flanges, slots and threads cooperate to lock the cartridge onto the drive unit in the second orientation with each thread seating in a respective one of the slots. The flanges can be positioned axially proximally in the coupling recess with respect to the slots; the cartridge is rotated from the first orientation to the second orientation by inserting the cartridge onto the drive end to axially advance the threads past the flanges to align the threads with the slots and by rotating the cartridge to seat the threads in the slots. 
     In such embodiments, flanges in coupling recess serve the dual purpose of ensuring proper angular orientation and axial insertion depth of the cartridge for the connection, in addition to aiding in retaining the cartridge on the drive unit once it is connected. If the threads on the drive end and the flanges in the coupling recess are positioned such that the threads are rotationally aligned with the flanges, the flanges will prevent the threads from being axially advanced past the flanges, requiring a proper angular orientation of the cartridge with respect to the drive unit to reach the proper insertion depth. In addition, if the cartridge is rotated for the connection prior to reaching that proper axial insertion depth, the flanges in the coupling recess instead will be axially aligned with the threads on the drive unit, such that the threads will inhibit rotation of the cartridge by abutting the flanges, thus preventing connection of the cartridge to the drive unit. In some embodiments, the threads and flanges can include corresponding concave and convex or otherwise mating surfaces, respectively, that interface with each other to prevent excess wear on the components due to such interactions. 
     In such embodiments, the slots in the cartridge recess and the corresponding threads on the drive mechanism can have additional complementary features to ensure a strong and reliable coupling of the cartridge to the drive unit. The threads can, for instance, include detent projections that nest into detent grooves in the slots when the cartridge has been rotated to seat the threads in the slots and provide tactile and even audible feedback to the user to confirm a secure and proper connection. These detents help prevent the cartridge from freely rotating with respect to the drive unit while still enabling the cartridge to be rotated in the opposite direction to disconnect the cartridge from the drive unit if a required amount of rotational force is applied. The threads can also increase in width from a leading edge of the threads that first enters the slots as the cartridge is rotated to provide a secure compression fit between the threads and the slots. 
     The above summary is not intended to describe each illustrated embodiment or every implementation of the subject matter hereof. The figures and the detailed description that follow more particularly exemplify various embodiments. 
     DETAILED DESCRIPTION 
       FIGS. 1A-1F  depict a patch pump  100  including a pump  102  and an attachment portion  104  according to an embodiment of the invention. Patch pump  100  does not include a built-in display or user interface, and is therefore primarily remote controlled. Retention frame  106  of attachment portion  104  includes an insertion portion  112  through which a disposable needle can be inserted to penetrate a sealing membrane and insert a cannula for medicament delivery. Reusable drive unit  118  of pump includes a drive mechanism  122  that mates with a recess  124  in disposable cartridge  116  to attach the cartridge  116  to the drive unit  118  and provide for delivery of medicament such as insulin from the cartridge  116  to a user through the cannula. 
     Retention frame  106  in this embodiment includes a hook portion  114  adjacent one end of the frame and a snap portion  115  adjacent an opposing end of the frame. To mate the pump  102  with the corresponding attachment portion  104 , initially hook portion  114  on retention frame  106  is inserted, or hooked, into a recess  138  in the drive unit  118 , as shown in  FIGS. 1C and 1D . To complete the insertion and mating process, the pump  102  is pivoted downwardly about the hook portion  114  to mate a recess  139  in cartridge  116  with snap portion  115 , as shown in  FIGS. 1E and 1F . Snap portion  115  can be flexible and resilient such that when the cartridge  116  is mated with the snap portion  115 , the snap portion  115  is initially pushed away from the pump  102  and then snaps into place when aligned with the recess  139  to cause an audible clicking or snapping sound that provides an indication to the user that the pump  102  is properly mated to the attachment portion  106 . Pump  102  can be released from attachment portion  104  to, for example, enable a user to exchange the cartridge, with one or more tabs  136 , which can be depressed to cause one or both of hook portion  114  and snap portion  115  to withdraw from its corresponding recess in pump  102 . 
     In one embodiment, and as shown in  FIGS. 2A-2C , cartridge  116  of pump  102  can attach to drive unit  118  with a quarter turn attachment. Recess  124  of cartridge  116  can be configured to initially attach to drive mechanism  122  of drive unit  118  such that an outer front housing surface  840  of the cartridge  116  is offset from an outer front housing surface  142  of the drive unit  818  at an angle of, e.g., about 90 degrees (generally perpendicular). The cartridge  116  can then be rotated toward the drive unit  118  a quarter-turn to align the outer surface  140  of the cartridge  116  generally parallel with the outer surface  142  of the drive unit  118  and secure the cartridge  116  on the drive unit  118 . In one embodiment, the engagement of the cartridge  116  to the drive unit  118  made by this rotation can cause an audible clicking sound that provides an auditory indication to the user that the cartridge is properly attached by the use of, e.g., detent projections and grooves described herein. Such a feature can alternatively or additionally provide a tactile indication to the user that the cartridge is properly attached. 
       FIGS. 3A-3D  depict further detail regarding such a cartridge  116  attachment. In these figures, a housing of the drive unit  118  is not shown and only the drive mechanism  122  is depicted for sake of clarity. Cartridge  116  can include a pair of opposing flanges  160  adjacent recess  124 , which can be comprised of a flexible material. Cartridge  116  can also include one or more detent projections  162 , with two such detent projections  162  depicted in this embodiment. The drive mechanism  122  can include one or more detent grooves  164  corresponding to the detent projections  162  on the cartridge, although alternatively the drive mechanism  122  could include the projections and the cartridge  116  could include the grooves. The drive mechanism  122  can also include one or more partial turn threads  166 , with this embodiment including a pair of quarter-turn threads on opposing sides of the mechanism. 
     To engage the cartridge  116  with the drive mechanism  122 , the drive end  123  of the drive mechanism  122  can be inserted into the recess  124  of the cartridge  116  with the quarter-turn threads  166  of the drive mechanism  122  offset from the flanges  160  of the cartridge  116 , as shown in  FIG. 3A . This enables the quarter-turn threads  166  to be inserted into the recess  124  past the flanges  160  so that when the cartridge  116  is rotated into alignment with the drive unit  118 , the quarter-turn threads  166  and the flanges  160  align with and axially abut and/or align with each other to prevent the threads  166  from being withdrawn back through the recess  124 . Therefore, interference between the quarter-turn threads  166  and the flanges  160  will prevent the cartridge  116  from being pulled directly off of the drive mechanism  122  in this alignment, keeping the cartridge rigidly affixed to the drive mechanism  122 . In addition, the detent projections  162  on the cartridge  116  nest into the detent grooves  164  in the drive mechanism  122  at the completion of the quarter-turn rotation. This prevents the cartridge  116  from freely rotating out of alignment with the drive unit  118 , and correspondingly the flanges  160  from freely rotating out of alignment with the quarter-turn threads  166 , while still enabling such rotation if a required amount of rotational force is applied. Although described as a “quarter-turn,” i.e., about a 90 degree rotation, it should be understood that a wide variety of rotational angles can be employed as discussed herein. 
     In one embodiment, the pump  102  is a syringe pump in which a plunger is incrementally advanced to dispense insulin or other medicament. Such pumps typically require a cap, such as a screw cap, to be disposed on the pump at an end of the syringe to prevent unintended dispensing of insulin. In the rotational attachment embodiment of the cartridge  116  described above, the rotation of the cartridge on attachment enables the cartridge to essentially function as a cartridge and an integrated screw cap to prevent unintended dispensing of insulin, thereby removing the need for the additional component of the screw cap. 
       FIGS. 4A-4B  and  FIGS. 5A-5B  depict that in some embodiments a pump such as pump  802  can be interchangeably used either with attachment portion  104  to deliver medicament to an infusion site beneath the pump  102  or with tubing  144  and a connector  146  to deliver medicament through an infusion site connector  148  displaced from the pump  102 . Pump  102  can include a recess  139 , more clearly shown in  FIG. 3C , that can include one or both of an opening (not pictured) configured to align with an insertion site  112  in the retention frame  106  and an opening  152  configured to connect to an end connector  154  of tubing  144 . Recess  139  can also aid in attaching pump  102  to the retention frame  106  as discussed with respect to  FIGS. 1C-1F . The pump  102  can therefore alternatively be used either with that attachment portion  104  as shown in  FIG. 4  or the tubing  144  and infusion site connector  148  as shown in  FIG. 5  according to user preference.  FIGS. 6A and 6B  further illustrate these alternative uses. Pump  102 A is depicted as being used with an attachment portion  104  carried directly on the user, whereas pump  102 B is depicted utilizing tubing  144  having an end connector  146  connecting to an infusion site connector  148  attached to the user with the pump  102 B carried in a separate location, such as in the user&#39;s pocket. 
       FIGS. 7A-7C  depict a remote control devices that can be used to control delivery of medicament and transfer data with a patch pump via Bluetooth, Bluetooth low energy, mobile or Wi-Fi communication, for example, according to embodiments of the present invention. Such a remote control could include, for example, a dedicated remote controller  171  as shown in  FIGS. 7B-7C , a mobile communication device  170  such as a smartphone as shown in  FIG. 7A , a wearable electronic watch or electronic health or fitness monitor or a personal digital assistant (PDA), etc. or a tablet, laptop or personal computer. 
     Referring to  FIGS. 7B-7C , a dedicated remote controller  171  according to embodiments of the invention can include a touchscreen display  173 . Touchscreen  173  can, in various embodiments, include a color display and be a capacitive touchscreen, resistive touchscreen, or the like and can be single touch or multi-touch touchscreen. Dedicated remote controller  171  can further include one or more of a touch-sensitive button  175 , a push button  177  and a port  179 . In some embodiments, touch-sensitive button  175  can be configured to return the controller  171  to a home screen from another menu screen any time the button  175  is touched and the push button  177  can be configured to wake the device from a sleep or off mode and activate the display  173  any time the button  177  is pressed. In other embodiments, these functions can be reversed or both functions can be accomplished with a single button depending on the current state of the device. Port  179  can be any type of port known in the art for data transfer and charging of a rechargeable battery in the controller  171 , such as, for example, a USB port. Controller  171  can additionally include one or more of a speaker/microphone, vibrator and/or light, such as an LED light, for providing alerts, alarms, notifications, etc. 
       FIG. 8  depicts a bolus button  172  located on the pump  102  that can also be used to initiate delivery of medicament with pump  102 . Because the depicted patch pump does not itself include a display or user interface, information and feedback regarding dosing initiated with the bolus button  172  can be communicated to and displayed on the remote control device  170 . 
     In some embodiments, patch pumps as described herein can interface with a glucose meter, such as a blood glucose meter (BGM) or a continuous glucose monitor (CGM), the latter category of which provides a substantially continuous estimated glucose level through a transcutaneous sensor that measures analytes, such as glucose, in the patient&#39;s interstitial fluid rather than the patient&#39;s blood. Patch pump system can use data obtained from a glucose meter such as a CGM to adjust therapy with patch pump either automatically, such as in a closed-loop or semi-closed loop “artificial pancreas” system, or by providing such data for user review via a remote control device  170 ,  171 . The data may be transmitted from the CGM to the patch pump and/or remote controller via a wireless transmitter, such as a near field communication (NFC) radio frequency (RF) transmitter or a transmitter operating according to a “Wi-Fi” or Bluetooth® protocol or the like, or the data may be transmitted via a wire connector. Further detail regarding CGM systems and definitions of related terms can be found in, e.g., U.S. Pat. Nos. 8,311,749, 7,711,402 and 7,497,827, each of which is hereby incorporated by reference in its entirety. 
       FIGS. 9A-9D  depict one example of a procedure or method for filling the cartridge  116  of a patch pump system  100  according to an embodiment of the present invention. Initially, the cartridge  116 —unattached to the drive unit of the pump—is connected to a disposable plunger  174  and a vial adapter  176 . As shown in  FIG. 9A , the user then pulls outwardly on the disposable plunger  174  in the direction of the arrow to draw air into the cartridge  116 . The vial adapter  176  is then connected to a vial  178  of medicament as shown in  FIG. 9B  and the disposable plunger is depressed in the direction of the arrow to expel the air that was drawn into the cartridge  116  into the vial  178 . This cartridge filling assembly is then turned upside down as shown in  FIG. 9C  and the disposable plunger  174  is again pulled outwardly in the direction of the arrow to draw medicament from the vial  178  to fill the cartridge. The vial  178 , vial adapter  176  and disposable plunger  174  are then disconnected from the cartridge  116  and the cartridge  116  is ready to be loaded onto a drive unit  118  of a pump as described herein. 
     Patch pumps according to embodiments of the present invention can include one or more rechargeable batteries in the drive unit. In some embodiments, a rechargeable battery can be inductively charged.  FIGS. 10A-10E  depict a procedure for inductively charging the one or more batteries of a patch pump according to one embodiment. Such an embodiment includes an inductive charging pad  180  as shown in  FIG. 10A . To charge the pump  102 , it is removed from attachment with the user&#39;s body ( FIG. 10B ) and/or disconnected from the tubing of the infusion set ( FIG. 10C ). The charging pad  180  can optionally include a cover  182  having a cutout sized to receive pump  102  in order to properly position and retain the pump  102  on the charging pad  180  such as is shown in  FIG. 10D . The pump  102  can be placed onto the charging pad  180  as shown in  FIG. 10E  where it will automatically be inductively charged when the pad  180  is connected to a power source. In some embodiments, a patch pump that can be inductively charged does not include a connection, such as a USB port, into which a power cord can be inserted for power transfer. Such an embodiment provides the advantages of being more robust for waterproofing because of the lack of exposed electrical contacts and obviating electrical isolation requirements imposed upon such connections. 
       FIGS. 11A-11E  depict one embodiment of a procedure for affixing the attachment portion  104  of a patch pump system to the skin of a user and inserting a cannula into the skin. First, an adhesive backing  107  can be removed from the adhesive patch  108  holding the retention frame  106  and the patch applied to the skin at the desired insertion site. Next, a cannula inserter  184  is aligned with the insertion portion  112  of retention frame  106  (see  FIGS. 1A-1B ) for insertion of a cannula into the user&#39;s skin. Proper alignment can be insured by inserting distally positioned feet  186  of the inserter  184  into slots in the retention frame  106  adjacent the insertion portion  112  as shown in  FIGS. 11B and 11C . In some embodiments, feet  186  can include a hook portion that hooks into the slots to maintain the position of the feet  186  within slots during the insertion process. The inserter  184  is pushed down in the direction of the arrow as shown in  FIG. 11D  to insert the cannula  188  and then removed leaving the cannula  188  in place on the frame and inserted through the skin as shown in  FIG. 11E .  FIGS. 12A-12D  show a substantially similar procedure for inserting a cannula into an infusion site located remotely from the pump such as is shown in  FIG. 5A-5B , with an infusion site connector  148  and an infusion site patch  190  used in place of adhesive patch  107  with retention frame  106 . In some embodiments, an audible sound such as a click sounding can indicate that the cannula has been properly inserted. 
     Referring now to  FIGS. 13A-13C , a patch pump  202  that can be used with patch pump systems as described herein according to another embodiment of the invention is depicted. Patch pump  202  is similar to patch pump  102  in that cartridge  216  is attached to drive unit  218  by axially moving and rotating cartridge  216  with respect to drive unit  818 . As shown in  FIGS. 13A-13B , the drive end  223  of the drive mechanism  222  of the drive unit  218  is axially inserted into a recess (not pictured) in the cartridge  216  with the outer front housing surface  240  of the cartridge  216  at an offset, non-parallel angle to the outer front housing surface  242  of the drive unit  218  and then the cartridge  216  is rotated to attach and lock the cartridge  216  in place on the drive unit  218  with the front surfaces  240 ,  242  parallel as shown in  FIG. 13C . In the depicted embodiment, the offset angle between the front surfaces  240 ,  242  at the initial attachment is approximately 60 degrees. The key aspect of such a rotation is that it enables locking features of the cartridge and drive unit to be initially aligned and then rotated into engagement with each other to lock the cartridge in place on the drive unit, which can be accomplished with a wide variety of angles in various embodiments. For example, in certain embodiments, this angle can be between about 30 degrees and about 150 degrees. 
     Also depicted in the embodiment of  FIGS. 13A-13C  is a short length of tubing  253  and a connector  252 . As can be seen in  FIGS. 14A and 14B , connector  252  is designed to connect to a connector  254  of an infusion set  245 . Infusion set  245  includes a length of tubing  244  extending from the connector  254  to a site connector  246  that connects to an infusion site connector as shown in, e.g.,  FIGS. 5A-5B  to deliver medicament to the infusion site. In some embodiments, connector  252  extending from cartridge  216  and connector  254  of infusion set  245  can be Luer Lock connections. 
     Further details regarding the connection features of the cartridge  216  and the drive unit  218  are shown in  FIG. 15  and  FIG. 16 , respectively. As noted above, cartridge  216  includes a coupling recess  224  into which drive end  223  of drive unit  218  is inserted by relative axial motion between cartridge  216  and drive unit  218 . Referring to  FIG. 15 , cartridge  216  defines a pair of slots  261  on opposing sides of recess  224  and a corresponding flange  260  located axially proximally of each slot  261  and projecting towards the center of recess  224 . A detent groove  262  is positioned on a surface  263  that defines both a proximal surface of slot  261  and a distal surface of flange  260 . Flange  260  further defines a convex stop feature  270 . An o-ring  274  can also be positioned within recess  224  to enhance sealing between and reduce wear and tear on the components. As shown in  FIG. 16 , drive mechanism  222 , shown without drive unit housing for sake of clarity, includes a pair of threads or locking wedges  266  configured to mate with the slots  261  defined in cartridge  216 , as will be discussed in further detail below. Threads  266  each further define a concave stop feature  268  that can cooperate with stop feature  270  of cartridge  216  to ensure proper angular alignment of the cartridge  216  and drive unit  218 , as will also be explained in further detail below. In some embodiments, threads or wedges, which could also be considered flanges, are flexible and elastically deform in order to form a proper connection. 
     As can be seen in  FIGS. 17A-17B , threads  266  on drive mechanism  222  are provided with a geometry that closes matches the geometry of slots  261  in cartridge  216 , including a detent projection  264  that matches the detent groove  262  in slot  261 . The geometry of threads  266  differs from that of slots  261  in that each thread  266  is a wedge that increases in width from a leading edge of the thread  266  defined by the stop feature  268  towards the detent projection  264 , whereas a width of the corresponding slot  261  remains generally constant. This narrower leading portion of the threads  266  enables the threads to easily be initially inserted into the slots  261  upon initial rotation of the cartridge  216  while providing a secure, compression fit as the wider portions of the threads  266  are forced into the slots  261  upon further rotation of the cartridge  216  relative to the drive mechanism  222 . A curved ramp  272  is providing on a trailing end of each thread  266  to ease the removal of the threads  266  from the slots  261  by rotating the cartridge  216  in the opposite direction. 
       FIG. 18A  depicts the proper angular orientation of cartridge  216  with respect to drive mechanism  222  for their relative axial movement to insert coupling recess  224  onto drive end  223 , thereby enabling connection of the cartridge  216  and the drive unit  218 . As can be seen in the figure, the threads  266  of drive mechanism  222  are rotationally offset from the slots  261  and flanges  260  in the recess  224  of cartridge  216 . If the threads  266  are not offset, as shown in  FIGS. 17A-17B , the flanges  260  would abut the threads  266  upon initial relative cartridge-drive mechanism relative axial movement, preventing further relative axial movement, which in turn prevents insertion of the drive end  223  further into the recess  223 . In this manner, the flanges  260  serve to ensure proper angular orientation of the cartridge  216  with respect to the drive unit so to effect a proper connection therebetween. When a proper angular orientation is achieved, the drive mechanism  222  is inserted into the recess  223  until the threads  266  have been advanced axially distal of the flanges  260 . 
     One the threads  266  have been axially aligned with the slots  261 , the cartridge  216  can now be rotated relative to drive mechanism  222 , in the direction of the arrow A in  FIGS. 18A-18B , to attach the cartridge  216  to the drive unit by mating the threads  266  with the slots  261 .  FIG. 18B  depicts a thread  266  partially seated within a slot  261  after partial rotation of the cartridge  216  with respect to the drive unit. As can be seen in the figure, the narrower leading edge of thread defined by stop feature  268  has enabled initial insertion of the thread  266  into the slot  261  and a compression fit has begun to form as the wider portions of thread  266  are forced into the slot  261 . This rotation continues until the detent projections  264  on threads  266  are seated in the detent grooves  262  in slots  261  as shown in  FIG. 18C , at which point the cartridge  216  is aligned flush with drive unit and the cartridge is prevented from further rotation by the leading edge of threads  266  abutting the ends  276  of the slots and the detent projections  264  nested in the detent slots  262 . The cartridge  216  cannot be distally moved away from the drive unit by the threads  266  being confined by the slots  261  and the flanges  260 . Curved ramp portions  272  of threads  266  are also held within slots  261  to retain the cartridge  216  in place, but rotation of the cartridge in the opposite direction of the insertion direction with a requisite amount of force to slide the detent projections  264  out of the detent grooves  262  will cause curved ramp portions  272  to slide out of slots  216  to enable disengagement of the cartridge  216  from the drive unit. 
       FIG. 19  depicts the operation of stop features  268  and  270 , which function to ensure that the drive mechanism  222  is inserted to the proper axial depth into recess  224  before the cartridge  216  is rotated. If the drive mechanism  222  is not inserted into the recess  224  such that the flanges  260  are advanced axially past the threads  266  to align the threads  260  with the slots  261 , when the cartridge  216  is rotated the stop features  168  at the leading edges of the threads  266  will encounter the stop features  270  of the flanges  260 . This prevents further rotation of the cartridge  216  relative to drive unit  218 . The convex mating configuration of the stop features  270  of the flanges  260  and concave configuration of the stop features  268  of the threads  266 , which, in certain embodiments, can be reversed or shaped differently, ensure that repeated contact between these components will not unreasonably stress or wear on the components. 
     After the cartridge has been installed on the drive unit according to the embodiments of the invention described herein, the cartridge is retained on the drive unit with sufficient force to minimize any compliance in the connection. As such, manufacturing tolerances for the flanges features on the disclosed cartridges are such that at the extents of the manufacturing tolerances the flanges flex with enough force upon the cartridge being installed onto the drive unit that when the drive mechanism is operated to push against a plunger in the cartridge to dispense medicament from the cartridge, there is no relative movement between the cartridge and the drive system. In one embodiment, the nominal flex or interference of the cartridge flanges is about 0.010 inches with a range due to tolerance stacking of about 0.006 to 0.014 inches. This enables the attachment to be sufficient to withstand force values of approximately 5 to 12 pounds, which in some embodiments is the maximum force output of the drive mechanism and equates to infusion pressures of approximately 20-50 psi. A benefit of minimizing this compliance is that it decreases the time to detect occlusions that are detected based on the motor stalling and minimizes the bolus a patient receives if an occlusion in the tubing is cleared to the pressure increase. 
     Although the pump system described herein is described as a user-wearable patch pump system that has no display or user interface and is primarily controlled by a remote device, it should be understood that aspects of the present disclosure can be incorporated into other types of infusion pumps. For example, full-featured user-wearable infusion pumps having display and input capabilities, such as a touchscreen display on the pump housing, such as disclosed in U.S. Pat. No. 8,287,495, which is hereby incorporated by reference herein, can incorporate aspects of the present disclosure. 
     Also incorporated herein by reference in their entirety are commonly owned U.S. Pat. Nos. 8,287,495; 8,408,421 8,448,824; 8,573,027; 8,650,937; 8,986,523; 9,173,998; 9,180,242; 9,180,243; 9,238,100; 9,242,043; and 9,335,910 commonly owned U.S. Patent Publication Nos. 2009/0287180; 2012/0123230; 2013/0053816; 2013/0159456; 2013/0324928; 2013/0331790; 2013/0332874; 2014/0273042; 2014/0276419; 2014/0276420; 2014/0276423; 2014/0276531; 2014/0276537; 2014/0276553; 2014/0276556 2014/0276569; 2014/0276570; 2014/0276574; 2014/0378898; 2015/0073337; 2015/0072613; 2015/0182693; 2015/0182694; 2015/0182695; 2016/0030669; and 2016/0082188 and commonly owned U.S. patent application Ser. No. 14/707,851 and commonly owned U.S. Provisional Application Ser. Nos. 61/911,576; 61/920,902; 61/920,914; 61/920,940; 62/139,275; 62/163,158; 62/207,748; 62/256,398; 62/272,255 and 62/300,410. 
     Further incorporated by reference herein in their entirety are U.S. Pat. Nos. 8,601,465; 8,502,662; 8,452,953; 8,451,230; 8,449,523; 8,444,595; 8,343,092; 8,285,328; 8,126,728; 8,117,481; 8,095,123; 7,999,674; 7,819,843; 7,782,192; 7,109,878; 6,997,920; 6,979,326; 6,936,029; 6,872,200; 6,813,519; 6,641,533; 6,554,798; 6,551,276; 6,295,506; and 5,665,065. 
     Various embodiments of systems, devices, and methods have been described herein. These embodiments are given only by way of example and are not intended to limit the scope of the claimed inventions. It should be appreciated, moreover, that the various features of the embodiments that have been described may be combined in various ways to produce numerous additional embodiments. Moreover, while various materials, dimensions, shapes, configurations and locations, etc. have been described for use with disclosed embodiments, others besides those disclosed may be utilized without exceeding the scope of the claimed inventions. 
     Persons of ordinary skill in the relevant arts will recognize that the subject matter hereof may comprise fewer features than illustrated in any individual embodiment described above. The embodiments described herein are not meant to be an exhaustive presentation of the ways in which the various features of the subject matter hereof may be combined. Accordingly, the embodiments are not mutually exclusive combinations of features; rather, the various embodiments can comprise a combination of different individual features selected from different individual embodiments, as understood by persons of ordinary skill in the art. Moreover, elements described with respect to one embodiment can be implemented in other embodiments even when not described in such embodiments unless otherwise noted. 
     Although a dependent claim may refer in the claims to a specific combination with one or more other claims, other embodiments can also include a combination of the dependent claim with the subject matter of each other dependent claim or a combination of one or more features with other dependent or independent claims. Such combinations are proposed herein unless it is stated that a specific combination is not intended. 
     Any incorporation by reference of documents above is limited such that no subject matter is incorporated that is contrary to the explicit disclosure herein. Any incorporation by reference of documents above is further limited such that no claims included in the documents are incorporated by reference herein. Any incorporation by reference of documents above is yet further limited such that any definitions provided in the documents are not incorporated by reference herein unless expressly included herein. 
     For purposes of interpreting the claims, it is expressly intended that the provisions of 35 U.S.C. § 112(f) are not to be invoked unless the specific terms “means for” or “step for” are recited in a claim.