Infusion device and driving mechanism for same

• US 7,396,353 B2
• Filed: 06/15/2004
• Issued: 07/08/2008
• Est. Priority Date: 09/07/2001
• Status: Expired due to Term

• Current Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Inventors: Bosley, Robert, Gray, John, Lorenzen, Eric
• Primary Examiner(s): Sirmons; Kevin C.
• Assistant Examiner(s): Gilbert; Andrew M
• Application Number:
  US10/867,785
• Publication Number:
  US 20040225281A1
• Time in Patent Office: 1,484 Days
• Field of Search: 604/890.1, 604/891.1, 60416701-16703, 604/141, 604/145, 251259- 65, 137/843, 137/847, 137/852, 137/859
• US Class Current: 604/891.1
• CPC Class Codes: A61M 2205/8212 with means or measures taken for minimising energy consumption
• CPC Class Codes: A61M 5/14216 Reciprocating piston type
• CPC Class Codes: A61M 5/14276 specially adapted for implantation
• CPC Class Codes: A61M 5/16877 Adjusting flow; Devices for setting a flow rate

Abstract

A drive mechanism for delivery of infusion medium a coil capable of being electrically activated to provide an electromagnetic field. The coil surrounds a piston channel extending in an axial direction. The piston channel provides a passage for communication of infusion medium to an outlet chamber located at one end of the piston channel. An armature is located adjacent the coil, on one side of the axial channel. The armature is moveable toward a forward position, in response to the electromagnetic field produced by activation of the coil. A piston is located within the piston channel and is moveable axially within the channel to a forward position, in response to movement of the armature to its forward position. The armature and piston are moved toward a retracted position, when the coil is not energized. In the retracted position of the piston, a piston chamber is formed between the piston and a valve member and is filled with infusion medium. As the piston is moved to its forward position, the piston chamber volume is reduced and pressure within the piston chamber increases to a point where the pressure moves the valve member into an open position. When the valve member is in the open position, medium from the piston chamber is discharged into an outlet chamber located on the opposite side of the coil relative to the armature. An outlet is provided in flow communication with the outlet chamber, for discharging infusion medium from the outlet chamber.

Claims

1. A drive mechanism for delivery of infusion medium comprising:

an inlet for receiving infusion medium;

an outlet for discharging infusion medium;

a piston channel through which infusion medium is communicated between the inlet and the outlet, the piston channel having an input side for receiving infusion medium received by the inlet, the piston channel also having a discharge side for discharging infusion medium from the piston channel for communication to the outlet;

a piston moveable within the piston channel between an quiescent position and a forward position to drive infusion medium from the piston channel toward the outlet;

a valve member facing a first end of the piston channel, the first end of the piston channel being on the discharge side of the piston channel, the valve member being moveable between closed and open positions to open and close the first end of the piston channel in conjunction with movement of the piston between quiescent and forward positions; and

a valve seat located adjacent the end of the piston channel that faces the valve member for contacting the valve member when the valve member is in closed position, the valve seat including a first surface and a second surface;

the valve member including at least one generally rigid stop surface for contacting the first surface of the valve seat upon valve member being in a closed position, the valve member further including a generally compliant portion extending toward the valve seat, beyond the generally rigid stop surface for contacting the second surface of the valve seat when the valve member is in a closed position,

wherein the first surface of the valve seat is projected toward the valve member relative to the second surface of the valve seat and is arranged to contact the at least one generally rigid stop surface, upon the valve member being in the closed position.

2. A drive mechanism as recited in claim 1, wherein the first and second surfaces of the valve seat are configured relative to the compliant portion of the valve member and the stop surface of the valve member, such that the compliant portion of the valve member contacts the second surface of the valve seat upon the stop surface of the valve member contacting the first surface of the valve seat.

3. A drive mechanism as recited in claim 1, wherein the first and second surfaces of the valve seat are configured relative to the compliant portion of the valve member and the stop surface of the valve member, such that the compliant portion of the valve member contacts the second surface of the valve seat prior to the stop surface of the valve member contacting the first surface of the valve seat.

4. A drive mechanism as recited in claim 1, wherein the first surface extends in a first plane and the second surface extends in a second plane that is different from and generally parallel to the first plane.

5. A drive mechanism as recited in claim 4, wherein the generally rigid stop surface of the valve member extends in a plane that is generally parallel to the first plane.

6. A drive mechanism as recited in claim 1, wherein the valve member is located adjacent to an outlet chamber.

7. A drive mechanism as recited in claim 1, wherein the generally compliant portion of the valve member faces the piston channel.

8. A drive mechanism as recited in claim 1, wherein the piston is moveable within the piston channel between the quiescent position and the forward position.

9. A drive mechanism as recited in claim 1, wherein the inlet, piston channel and outlet are arranged to define a fluid flow path for the infusion medium to flow in through the inlet and then through the piston channel and then discharged from the outlet.

10. A drive mechanism for delivery of infusion medium comprising:

an inlet for receiving infusion medium;

an outlet for discharging infusion medium;

a piston channel through which infusion medium is communicated between the inlet and the outlet, the piston channel having an input side for receiving infusion medium received by the inlet, the piston channel also having a discharge side for discharging infusion medium from the piston channel for communication to the outlet;

a piston moveable within the piston channel between an quiescent position and a forward position to drive infusion medium from the piston channel toward the outlet;

a valve member facing a first end of the piston channel, the first end of the piston channel being on the discharge side of the piston channel, the valve member being moveable between closed and open positions to open and close the first end of the piston channel in conjunction with movement of the piston between quiescent and forward positions; and

a valve seat located adjacent the end of the piston channel that faces the valve member for contacting the valve member when the valve member is in closed position;

the valve member including at least one generally rigid stop surface for contacting the valve seat upon the valve member being in a closed position, the valve member further including a generally compliant portion extending toward the valve seat, beyond the generally rigid stop surface for contacting the valve seat when the valve member is in a closed position,

wherein the valve seat includes at least one projecting surface and at least one further surface, the at least one projecting surface is projected toward the valve member relative to the at least one further surface, the at least one projecting surface arranged to contact the generally rigid stop surface, and the at least one further surface arranged to contact the generally compliant portion, upon the valve member being in the closed position.

11. A drive mechanism as recited in claim 10, wherein the at least one projecting portion and the at least one further surface of the valve seat is configured relative to the compliant portion of the valve member and the at least one generally rigid stop surface of the valve member, such that the projecting portion of the valve seat contacts the at least one generally rigid stop surface of the valve member upon the at least one generally compliant portion of the valve member making contact with the at least one further surface.

12. A drive mechanism as recited in claim 10, wherein the projecting surface extends in a first plane and the further surface extends in a second plane that is different from and generally parallel to the first plane.

13. A drive mechanism as recited in claim 12, wherein the generally rigid stop surface of the valve member extends in a plane that is generally parallel to the first plane.

14. A drive mechanism as recited in claim 10, wherein the valve member is located adjacent to an outlet chamber.

15. A drive mechanism as recited in claim 10, wherein the generally compliant portion of the valve member faces the piston channel.

16. A drive mechanism as recited in claim 10, wherein the piston is moveable within the piston channel between the quiescent position and the forward position.

17. A drive mechanism as recited in claim 16, wherein the inlet, piston channel and outlet are arranged to define a fluid flow path for the infusion medium to flow in through the inlet and then through the piston channel and then discharged from the outlet.