Fluid reservoir piston

• US 6,800,071 B1
• Filed: 10/27/2000
• Issued: 10/05/2004
• Est. Priority Date: 10/29/1998
• Status: Expired due to Term

• Current Assignee: Minimed, Inc. (Medtronic Plc)
• Original Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Inventors: McConnell, Susan, Moberg, Sheldon B.
• Primary Examiner(s): Casler, Brian L.
• Assistant Examiner(s): RODRIGUEZ, CRIS LOIREN
• Application Number:
  US09/698,783
• Time in Patent Office: 1,439 Days
• Field of Search: 604/181, 604/213, 604/218, 604/220, 604/221, 604/224, 604/225, 604/228, 604/235, 604/187, 604/152, 604/154, 604/131, 604/151, 604/155, 128/DIG.1, 128/DIG.12, 128/DIG.13, 215/364, 215/355, 215/DIG.3
• US Class Current: 604/155
• CPC Class Codes: A61M 2005/1623 Details of air intake
• CPC Class Codes: A61M 2205/581 by audible feedback
• CPC Class Codes: A61M 2205/582 by tactile feedback
• CPC Class Codes: A61M 39/10 Tube connectors; Tube couplings A61M39/02 takes precedence; connecting needles to syringes or hubs A61M5/34; connecting catheter tubes to hubs A61M25/0014
• CPC Class Codes: A61M 39/12 for joining a flexible tube to a rigid attachment
• CPC Class Codes: A61M 39/14 for connecting tubes having sealed ends needle sets A61M5/162; having valves closing automatically on disconnection of line A61M39/26
• CPC Class Codes: A61M 5/1452 pressurised by means of pistons
• CPC Class Codes: A61M 5/1456 with a replaceable reservoir comprising a piston rod to be moved into the reservoir, e.g. the piston rod is part of the removable reservoir
• CPC Class Codes: A61M 5/14566 with a replaceable reservoir for receiving a piston rod of the pump
• CPC Class Codes: A61M 5/162 Needle sets, i.e. connections by puncture between reservoir and tube ; Connections between reservoir and tube in jet-action syringes A61M5/30; connectors for tubes having sealed ends and a needle for piercing them A61M39/14
• CPC Class Codes: A61M 5/16831 Monitoring, detecting, signalling or eliminating infusion flow anomalies low-level float-valves causing cut-off A61M5/40; indicating or recording presence, absence or direction of flow in general G01P13/0066
• CPC Class Codes: Y10S 128/01 Motorized syringe
• CPC Class Codes: Y10S 128/12 Pressure infusion

Abstract

An improved pump, reservoir and reservoir piston are provided for controlled delivery of fluids. A motor is operably coupled to a drive member, such as a drive screw, which is adapted to advance a plunger slide in response to operation of the motor. The plunger slide is removably coupled to the piston. The piston comprises a first member and a second member. The first member has an external proximate side and an external distal side. The external proximate side is adapted to contact the fluid and is made of a material having a first stiffness. The second member has a first side and a second side and is at least partially disposed within the first member. The first side of the second member is adjacent to the external proximate side of the first member and is made of a material having a stiffness which is greater than the first stiffness.

Claims

1. An apparatus for dispensing a medication fluid comprising:

a reservoir adapted to contain the fluid and adapted for use with a drive system having a threaded linear actuation member; and

a piston comprising;

a first member adapted to be slidably mounted within the reservoir and adapted to form a fluid-tight barrier within the reservoir;

the first member having an external proximate side and an external distal side, the external proximate side being adapted to contact the fluid and being made of a material having a first stiffness, the external distal side including threads adapted to releasably engage the threaded linear actuation member;

a second member having a first side and a second side, the first side and the second side of the second member being entirely contained within the first member and being adapted not to contact the fluid; and

the first side of the second member being adjacent to the external proximate side of the first member and being made of a material having a stiffness which is greater than the first stiffness.

2. The apparatus of claim 1 wherein the first side of the second member is in a generally parallel, spaced-apart relationship with the external proximate side of the first member.

3. The apparatus of claim 1 wherein the material of the first member external proximate side has a thickness defined by the distance between the first member external proximate side and the second member first side, and wherein the thickness is generally uniform.

4. The apparatus of claim 1 wherein the first member external proximate side is made of an elastomeric material and the second member first side is made of one of stainless steel and plastic.

5. The apparatus of claim 1 wherein the second member has a generally incompressible structure.

6. The apparatus of claim 1 wherein the first member has a cavity and the external distal side of the first member has an opening leading into the cavity, the cavity having an internal proximate wall and an internal side wall, the internal proximate wall being adjacent to the external proximate side.

7. The apparatus of claim 6 wherein the internal proximate wall of the cavity and the external proximate side are in a generally parallel spaced-apart relationship.

8. The apparatus of claim 6 wherein the material of the first member external proximate side has a thickness defined by the distance between the external proximate side and the internal proximate wall of the cavity, and wherein the thickness is generally uniform.

9. The apparatus of claim 1 wherein the first member has a cavity and wherein the external distal side of the first member has an opening leading into the cavity, the cavity comprising:

a first chamber extending from the external distal side into the cavity; and

a second chamber extending from the first chamber to an internal proximate wall, the internal proximate wall being disposed adjacent to the external proximate side;

and wherein the second member is disposed within the second chamber.

10. The apparatus of claim 9 wherein the first chamber is defined by a generally cylindrically-shaped first wall extending axially from the external distal side into the cavity, and wherein the second chamber is defined by:

a generally cylindrically-shaped second wall extending axially from the generally cylindrically-shaped first wall into the cavity, the generally cylindrically-shaped second wall having a radius which is greater than that of the generally cylindrically-shaped first wall;

a ledge extending from the generally cylindrically-shaped first wall to the generally cylindrically-shaped second wall; and

the internal proximate wall.

11. The apparatus of claim 10 wherein the internal proximate wall of the second chamber and the first member external proximate side are in a generally parallel spaced-apart relationship.

12. The apparatus of claim 11 wherein the internal proximate wall has a generally conical shape and the external proximate side has a generally conical shape.

13. The apparatus of claim 12 wherein the second member has a conical face portion which terminates in a spherically-shaped end portion.

14. The apparatus of claim 12 wherein the second member has a generally conical face, a generally cylindrical side wall and a planar back wall, the generally conical face being adapted to mate with the internal proximate wall and the second member being adapted to seat against the ledge.

15. The apparatus of claim 14 wherein the first member is made of an elastomeric material and the second member is made of one of stainless steel and plastic.

16. An apparatus for dispensing a medication fluid comprising:

a reservoir adapted to contain the fluid and adapted for use with a drive system having a threaded linear actuation member; and

a piston comprising;

a first member adapted to be slidably mounted within the reservoir and adapted to form at least part of a fluid-tight barrier within the reservoir;

the first member having an external proximate side and an external distal side, the external proximate side being adapted to contact the fluid and being made of a material having a first stiffness;

wherein the first member has a cavity and wherein the external distal side of the first member has an opening leading into the cavity, the cavity comprising;

a first chamber extending from the external distal side into the cavity; and

a second chamber extending from the first chamber to an internal proximate wall, the internal proximate wall being disposed adjacent to the external proximate side;

wherein the first chamber is defined by a generally cylindrically-shaped first wall extending axially from the external distal side into the cavity, and the generally cylindrically shaped first wall has threads adapted to releasably engage the threaded linear actuation member; and

wherein the second chamber is defined by;

a generally cylindrically-shaped second wall extending axially from the generally cylindrically-shaped first wall into the cavity, the generally cylindrically-shaped second wall having a radius which is greater than that of the generally cylindrically-shaped first wall;

a ledge extending from the generally cylindrically-shaped first wall to the generally cylindrically-shaped second wall; and

the internal proximate wall; and

a second member having a first side and a second side, at least a portion of the second member being disposed within the first member;

the first side of the second member being adjacent to the external proximate side of the first member and being made of a material having a stiffness which is greater than the first stiffness;

wherein the second member is disposed within the second chamber.

17. The apparatus of claim 16 wherein the threads have a 2 start, 40 thread per inch pitch.

18. An apparatus for dispensing a medication fluid comprising:

a reservoir adapted to contain the fluid;

a piston comprising;

a first member adapted to be slidably mounted within the reservoir and adapted to form at least part of a fluid-tight barrier within the reservoir;

the first member having an external proximate side and an external distal side, the external proximate side being adapted to contact the fluid and being made of a material having a first stiffness; and

a second member having a first side and a second side, at least a portion of the second member being disposed within the first member;

the first side of the second member being adjacent to the external proximate side of the first member and being made of a material having a stiffness which is greater than the first stiffness; and

a drive system including a linear actuation member, wherein the piston first member is adapted to be releasably coupled to the linear actuation member, and further wherein the linear actuation member includes a first threaded member and the piston first member includes a second threaded member adapted to engage the first threaded member.

19. The apparatus of claim 18 wherein the first threaded member comprises a screw extending from the linear actuation member and having external threads, and the second threaded member comprises a cavity defined by the first member and having internal threads positioned to be engaged by the screw external threads.

20. The apparatus of claim 19 wherein the external threads of the screw are made of a material having a first hardness and the internal threads of the first member cavity are made of a material having a second hardness.

21. The apparatus of claim 19 wherein the external threads of the screw have a first lead and wherein the internal threads of the first member cavity have a second lead.

22. A piston for a reservoir adapted to contain a fluid and adapted for use with a drive system having a threaded linear actuation member, the piston comprising:

a first member adapted to be slidably mounted within the reservoir and adapted to form a fluid-tight barrier within the reservoir;

the first member having an external proximate side and an external distal side, the external proximate side being adapted to contact the fluid and being made of a material having a first stiffness, and the external distal side including threads adapted to releasably engage the threaded linear actuation member; and

a second member having a first side and a second side, the first side and the second side of the second member being adapted to be entirely contained within the first member and not to contact the fluid, and the second member being adjacent to the external proximate side of the first member for providing a second stiffness to the external proximate side, the second stiffness being greater than the first stiffness.

23. The piston of claim 22 wherein the external proximate side of the first member is generally conical in shape.