DRIVE MECHANISM FOR INFUSION PUMP

• US 20170049957A1
• Filed: 08/19/2016
• Published: 02/23/2017
• Est. Priority Date: 08/20/2015
• Status: Active Grant

• Current Assignee: Tandem Diabetes Care Incorporated
• Original Assignee: Tandem Diabetes Care Incorporated
• Inventors: Michaud, Michael
• Granted Patent: US 10,279,107 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61M 2005/14268 with a reusable and a disposable component
• CPC Class Codes: A61M 2205/103 rotating
• CPC Class Codes: A61M 2205/3306 Optical measuring means
• CPC Class Codes: A61M 2205/3317 Electromagnetic, inductive or dielectric measuring means
• CPC Class Codes: A61M 5/14248 of the skin patch type
• CPC Class Codes: A61M 5/1452 pressurised by means of pistons

Abstract

A patch pump utilizes piezoelectricity to dispense medicament from a cartridge syringe to a patient. Pump can include a plurality of piezoelectric elements that when energized cause linear motion of a pushrod that interfaces with the syringe in the cartridge to advance the syringe and dispense the medicament. The high torque generated by the piezoelectric elements is directly converted into the same amount of torque on the lead screw, so no torque increasing gear reduction system is needed and the pushrod utilized to drive the syringe can be contained within and connected directly to the motor assembly. Such a piezoelectric-based system can therefore be made smaller and with fewer moving parts than an electromagnetic motor of the same capability such that the pump has a smaller size than has heretofore been possible with prior art electromagnetic-based syringe pumps and other pumps that utilize gear reduction systems.

Claims

1. A user-wearable infusion pump, comprising:

a disposable cartridge including a reservoir configured to contain a medicament, the disposable cartridge including a plunger at a proximal end of the reservoir and an outlet port in fluid communication with the reservoir at a distal end of the reservoir;

a drive unit including at least one piezoelectric motor and a pushrod, wherein the drive unit is configured such that when the piezoelectric motor is energized with an electrical drive signal, the piezoelectric motor causes linear motion of the pushrod that moves the plunger to cause medicament to flow from the reservoir out of the outlet port to a patient without a gear reduction system.

2. The user-wearable infusion pump of claim 1, wherein the drive unit further comprises a drive disk in contact with the at least one piezoelectric motor, and wherein energizing the at least one piezoelectric motor induces rotational motion of the drive disk that is converted into the linear motion of the pushrod.

3. The user-wearable infusion pump of claim 2, wherein the drive disk comprises a ceramic material.

4. The user-wearable infusion pump of claim 2, further comprising a drive tube connected to the drive disk and a threaded lead screw positioned within the push rod and connected to the drive tube, and wherein rotation of the drive disk causes rotation of the drive tube and the lead screw.

6. The user-wearable infusion pump of claim 2, wherein the at least one piezoelectric motor includes a drive tip in contact with the drive disk, and wherein the drive tip is biased into contact with the drive disk.

7. The user-wearable infusion pump of claim 4, wherein an outer circumferential surface of the drive tube includes a plurality of markings, and the drive unit further comprises an optical encoder configured to monitor the markings to determine rotational positions of the drive tube.

8. The user-wearable infusion pump of claim 1, wherein the at least one piezoelectric motor consists of three piezoelectric motors concentrically arranged around the drive unit.

5. The user-wearable infusion pump of claim 5, further comprising a guide bushing surrounding a portion of the pushrod, the guide bushing preventing the pushrod from rotating such that the rotation of the drive disk, drive tube and lead screw causes the linear motion of the pushrod.

9. A user-wearable infusion pump, comprising:

a disposable cartridge including a reservoir configured to contain a medicament, the disposable cartridge including a plunger at a proximal end of the reservoir and an outlet port in fluid communication with the reservoir at a distal end of the reservoir;

a drive unit including

a drive disk having a body defining a central opening;

a motor configured to cause the drive disk to rotate;

a drive tube extending through the central opening of the drive disk and coupled to the drive disk such that rotation of the drive disk causes rotation of the drive tube;

an externally threaded lead screw coupled to the drive tube such that rotation of the drive tube causes rotation of the lead screw;

a pushrod having a distal tip, the pushrod having internal threads configured to mate with the externally threaded lead screw; and

a guide bushing surrounding a portion of the pushrod that prevents rotation of the pushrod,

wherein actuation of the motor to rotate the drive disk causes the pushrod to be linearly advanced such that the distal tip contacts the plunger in the cartridge and moves the plunger to dispense medicament from the reservoir out the outlet port.

10. The user-wearable infusion pump of claim 9, wherein the motor is a piezoelectric motor.

11. The user-wearable infusion pump of claim 10, wherein the piezoelectric motor includes a drive tip in contact with the drive disk, and wherein the drive tip is biased into contact with the drive disk.

12. The user-wearable infusion pump of claim 10, wherein there are three piezoelectric motors concentrically arranged around the drive disk.

13. The user-wearable infusion pump of claim 9, wherein the drive disk comprises a ceramic material.

14. The user-wearable infusion pump of claim 9, wherein an outer circumferential surface of the drive tube includes a plurality of markings, and the drive unit further comprises an optical encoder configured to monitor the markings to determine rotational positions of the drive tube.

15. The user-wearable infusion pump of claim 9, wherein an outer perimeter of the pushrod is non-circular.

16. A user-wearable infusion pump, comprising:

a reservoir configured to contain a medicament;

an outlet port in fluid communication with the reservoir;

at least one piezoelectric motor; and

a pushrod,

wherein when the at least one piezoelectric motor is energized with an electrical drive signal, the at least one piezoelectric motor causes linear motion of the pushrod without a gear reduction system that causes medicament to flow from the reservoir out of the outlet port to a patient.

17. The user-wearable infusion pump of claim 16, wherein the drive unit further comprises a drive disk in contact with the at least one piezoelectric motor, and wherein energizing the at least one piezoelectric motor induces rotational motion of the drive disk that is converted into the linear motion of the pushrod.

18. The user-wearable infusion pump of claim 17, further comprising a drive tube connected to the drive disk and a threaded lead screw positioned within the push rod and connected to the drive tube, and wherein rotation of the drive disk causes rotation of the drive tube and the lead screw.

19. The user-wearable infusion pump of claim 18, further comprising a guide bushing surrounding a portion of the pushrod, the guide bushing preventing the pushrod from rotating such that the rotation of the drive disk, drive tube and lead screw causes the linear motion of the pushrod.

20. The user-wearable infusion pump of claim 18, wherein an outer circumferential surface of the drive tube includes a plurality of markings, and the drive unit further comprises an optical encoder configured to monitor the markings to determine rotational positions of the drive tube.