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US-12616790-B2 - Pumping mechanism with wire-pulled plunger

US12616790B2US 12616790 B2US12616790 B2US 12616790B2US-12616790-B2

Abstract

Disclosed herein are devices and methods for causing the linear translation of a plunger through a reservoir containing a fluid. A flexible member, for example, a wire or a ribbon, is coupled to the plunger and extends through a wall of the reservoir toward which the plunger is being linearly translated. A pulling force on the flexible member caused by a drive mechanism causes the plunger to linearly translate toward the end wall of the reservoir, thereby forcing any fluid contained in the reservoir out of the reservoir through a fluid port.

Inventors

  • Daniel Barrett
  • Soroush KAMRAVA
  • Maureen McCaffrey

Assignees

  • INSULET CORPORATION

Dates

Publication Date
20260505
Application Date
20220217

Claims (20)

  1. 1 . A device comprising: a reservoir having walls including a first wall and a second wall and a distal end comprising a fluid port; a plunger configured to be linearly translated through the reservoir; a flexible member, rigidly coupled to the plunger, that is configured to move across an interior of the reservoir inside the walls in a longitudinal direction towards the distal end of the reservoir, and configured to move across an exterior of the reservoir outside the walls in a reverse-longitudinal direction opposite the longitudinal direction, wherein the flexible member extends through the first wall at the distal end of the reservoir and through the second wall of the reservoir on a second end opposite the distal end; and a drive mechanism for pulling the flexible member to cause a linear translation of the plunger through the reservoir.
  2. 2 . The device of claim 1 , wherein linear translation of the plunger through the reservoir forces a fluid contained in the reservoir through the fluid port.
  3. 3 . The device of claim 1 , wherein the flexible member is a wire.
  4. 4 . The device of claim 3 , further comprising: an opening, defined in an end of the reservoir; and a septum, sealing the opening and allowing the wire to pass therethrough.
  5. 5 . The device of claim 3 , wherein the drive mechanism comprises: a pair of rollers in frictional engagement with the wire and rotating in opposite directions.
  6. 6 . The device of claim 5 , further comprising: a gear, coupled to each of the rollers; wherein the gears are in rotational engagement with each other.
  7. 7 . The device of claim 6 wherein at least one of the gears is rotationally driven such as to cause the rotation of the rollers in opposite directions.
  8. 8 . The device of claim 3 wherein the wire is insulated such as to be able to form a fluid seal with a septum.
  9. 9 . The device of claim 8 wherein a circumferential surface of each of a pair of rollers defines a knurled pattern, such as to cause a frictional engagement with the insulation of the wire.
  10. 10 . The device of claim 3 wherein the wire is a stranded wire.
  11. 11 . The device of claim 3 wherein the wire forms a complete, taut loop and further wherein the wire passes through the plunger such as to prevent movement of the plunger absent a movement of the wire caused by the drive mechanism.
  12. 12 . The device of claim 11 further comprising: a plurality of roller members for forming the wire into the taut loop.
  13. 13 . The device of claim 1 , wherein the flexible member is a ribbon.
  14. 14 . The device of claim 13 wherein the drive mechanism comprises: a clutch mechanism engaging the ribbon; and a leadscrew in threaded engagement with the clutch mechanism, wherein rotation of the leadscrew causes a linear translation of the clutch mechanism along an outside surface of the reservoir.
  15. 15 . The device of claim 14 , wherein the clutch mechanism comprises: a housing; a spring; and an engagement member; wherein the spring holds the ribbon in frictional engagement between the housing and the engagement member.
  16. 16 . The device of claim 15 wherein the clutch mechanism further comprises: a trigger mechanism for holding the engagement member away from the ribbon such as to allow free movement of the ribbon prior to the trigger mechanism being tripped.
  17. 17 . The device of claim 14 wherein an exterior surface of the reservoir defines a guide thereon and further wherein the clutch mechanism is engaged with the guide as the clutch mechanism translates linearly along the exterior surface of the reservoir.
  18. 18 . The device of claim 13 wherein the ribbon is composed of coated fiberglass or metal.
  19. 19 . The device of claim 13 wherein the ribbon forms a complete, taut loop and further wherein the ribbon passes through the plunger such as to prevent movement of the plunger absent a movement of the ribbon caused by the drive mechanism.
  20. 20 . The device of claim 19 further comprising: a plurality of rollers for forming the ribbon into the taut loop.

Description

RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application No. 63/160,240, filed Mar. 12, 2021, entitled “IMPROVED DRIVE MECHANISMS FOR POSITIVE DISPLACEMENT PUMPS”, and U.S. Provisional Patent Application No. 63/306,765, filed Feb. 4, 2022, entitled “PUMPING MECHANISM WITH WIRE-PULLED PLUNGER”. The contents of these application are incorporated herein in their entireties. BACKGROUND Many conventional automatic drug delivery systems are well known, including, for example, wearable drug delivery devices of the type shown in FIG. 2. The drug delivery device 102 can be designed to deliver any type of liquid drug to a user. In specific embodiments, the drug delivery device 102 can be, for example, an OmniPod® drug delivery device manufactured by Insulet Corporation of Acton, Massachusetts. The drug delivery device 102 can be a drug delivery device such as those described in U.S. Pat. Nos. 7,303,549, 7,137,964, or 6,740,059, each of which is incorporated herein by reference in its entirety. Drug delivery device 102 typically includes a positive displacement pump mechanism. Typically, the pump mechanism comprises a reservoir that stores the liquid drug. The liquid drug stored in the reservoir may be delivered to the user by expelling the drug from a reservoir using a driven plunger that longitudinally translates though the reservoir to force the liquid drug through a fluid port defined in the reservoir. The plunger may be longitudinally translated through the reservoir by, for example, a rigid leadscrew which pushes the plunger forward during pumping. When the reservoir is filled, the leadscrew travels backwards with the plunger. The leadscrew extends past the back of the plunger a distance equal to the stroke of the plunger plus an additional amount to allow for engagement with the drive mechanism. This leads to a space efficiency constraint when scaling the design. If the stroke of the plunger increases, the length of the leadscrew must increase by the same amount. In wearable, on-body devices, it is desirable to keep the pump mechanism, as well as the overall drug delivery device 102, as small as possible to minimize the impact to the wearer. Additionally, because such drug delivery devices are typically powered by an on-board battery, it is desirable to minimize the power required to operate the device. Therefore, it would be desirable to replace the prior art pump mechanism with a positive displacement pump having a more space-efficient pumping mechanism to allow for a smaller device, which would decrease the burden on the user. Definitions As used herein, the term “liquid drug” should be interpreted to include any drug in liquid form capable of being administered by a drug delivery device via a subcutaneous cannula, including, for example, insulin, GLP-1, pramlintide, morphine, blood pressure medicines, chemotherapy drugs, fertility drugs or the like or co-formulations of two or more of GLP-1, pramlintide, and insulin. SUMMARY This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended as an aid in determining the scope of the claimed subject matter. A first embodiment of the invention disclosed herein uses a flexible wire to pull the plunger through the reservoir to deliver the liquid drug to the user. A pair of mated rollers grips on the wire and one of the rollers is driven to rotate the rollers, thereby advancing the wire. The wire is fixed to the plunger so that the plunger advances through the reservoir as the wire is pulled by the rollers. A second embodiment of the invention disclosed herein uses a flexible ribbon instead of a wire to pull the plunger through the reservoir. The ribbon is pulled by a clutch mechanism which grabs the ribbon. The clutch mechanism is coupled to a leadscrew which longitudinally translates the clutch mechanism along the exterior of the reservoir to pull the ribbon, which is coupled to the plunger. The clutch mechanism may be disengaged from the ribbon to allow filling of the reservoir, which requires that the plunger be able to move in a direction opposite the direction in which the ribbon pulls the plunger. In either embodiment, by having the wire or ribbon configured in as a taut, closed loop, the plunger is supported in both directions, which prevents advancement of the plunger in either direction due to changes in atmospheric pressure. This mechanism also eliminates some challenges that are inherent in a system in which the wire or ribbon is spooled, as spooling changes the distance from the center of the roller to the wire or ribbon, which introduces inaccuracies in the delivery of the liquid drug. The workings of both embodiments is described in further detail below. BRIEF DESCRIPTION OF THE DRAWINGS In the drawings, like