Drive system for an infusion pump

• US 7,025,226 B2
• Filed: 10/18/2004
• Issued: 04/11/2006
• Est. Priority Date: 04/13/2001
• Status: Expired due to Term

• Current Assignee: Trividia Healthcare Systems, LLC
• Original Assignee: Nipro Diabetes Systems, Inc.
• Inventors: Ramey, Kirk
• Primary Examiner(s): Nicolas, Frederick C.
• Application Number:
  US10/967,901
• Publication Number:
  US 20050051580A1
• Time in Patent Office: 540 Days
• Field of Search: 222/1, 222/63, 222/153.13, 222325-327, 222/333, 222/386, 222/390, 604152-155
• US Class Current: 222/1
• CPC Class Codes: A61M 2005/14264 with means for compensating influence from the environment
• CPC Class Codes: A61M 5/14244 adapted to be carried by the patient, e.g. portable on the body
• 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 5/16831 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: A61M 5/16854 by monitoring line pressure

Abstract

A pump system for an infusion system includes a linear drive (36, 36′) which minimizes the space occupied by the pump components in a portable housing (10, 10′). A motor (34) and a motor drive shaft (42) are arranged in parallel with, and adjacent to a syringe (14, 14′) and lead screw (94, 94′). A gear box (54) connects the drive shaft and lead screw to transfer rotational movements between them. A piston driving member, such as a cone (116) or drive nut (116′) converts the rotational movement of the lead screw into linear motion of a syringe piston (24). Sensors (150, 152) detect when the piston or cone is in a “home” position and in an “end” position, respectively. Optionally, a proximity sensor (170) is used to ensure that the cone and the piston (24) are abutting during dispensing. Alternatively, a clamping member (350) selectively clamps the lead screw (94′) against linear motion in at least a dispensing direction.

Claims

1. A method of dispensing a liquid from a barrel of a cassette having a piston, comprising the steps of:

(a) coupling a piston drive member to the piston, the piston drive member carrying a rotatable shaft;

(b) coupling the rotatable shaft with a drive system which rotates the shaft, wherein the drive system is operatively connected with a motor;

(c) actuating a clamping means which clamps the shaft against linear motion in a dispensing direction;

(d) actuating the drive system to continuously rotate the shaft to advance the piston drive member and the piston to dispense the fluid from the barrel, and

(e) providing a guide element to telescopically receive at least a portion of the piston drive member and inhibit rotation of the piston drive member during linear advancement of the piston drive member.

2. The method of claim 1, wherein step (b) includes:

inserting the piston, drive member, and shaft into a housing which houses the drive system.

3. The method of claim 1, wherein step (c) includes:

moving the clamping means from a first position, in which the clamping means is spaced from the shaft, to a second position, in which the clamping means engages the shaft.

4. A method of dispensing a medicament from a cartridge including a barrel which receives a piston comprising the steps of:

(a) bringing a piston drive member and the piston into an abutting relationship in a first position;

(b) providing a guide element to telescopically receive at least a portion of the piston drive member and inhibit rotation of the piston drive member during linear advancement of the piston drive member;

(c) sensing that the piston drive member is in the first position and sending a signal to a controller;

(d) advancing the piston drive member incrementally under the control of the controller to advance the piston to dispense the fluid from the barrel until the piston drive member is in a second position linearly spaced from the first position; and

(e) sensing that the piston drive member is in the second position and sending a signal to a controller.

5. The method of claim 4, further including, after step (e), the controller arresting advancement of the piston drive member.

6. The method of claim 4, wherein the piston drive member further includes an extension member attachable to the guide element to provide a coupling relationship with the guide member during linear advancement of the piston, the guide member movable along the threaded rotatable shaft during linear advancement of the piston.