Method for Ensuring Constant Speed of a Motor in an Injection Device

• US 20080221513A1
• Filed: 01/17/2006
• Published: 09/11/2008
• Est. Priority Date: 02/21/2005
• Status: Active Grant

• Current Assignee: Novo Nordisk A/S
• Original Assignee: Novo Nordisk A/S
• Inventors: Nyholm, Kim, Jensen, Bo Vestergard
• Granted Patent: US 7,993,300 B2
• Time in Patent Office: Days
• US Class Current: 604/67
• CPC Class Codes: A61M 2205/3365 Rotational speed
• CPC Class Codes: A61M 2205/50 with microprocessors or computers
• CPC Class Codes: A61M 2205/70 with testing or calibration facilities
• CPC Class Codes: A61M 2205/8206 battery-operated
• CPC Class Codes: A61M 5/1452 pressurised by means of pistons
• CPC Class Codes: H02P 7/2805 whereby the speed is regulated by measuring the motor speed and comparing it with a given physical value

Abstract

The present invention relates to a method for ensuring a constant target speed of a battery driven electrical motor, the battery driven electrical motor being adapted to move a piston rod in an injection device so as to inject a set dose of medicine from the injection device, the method comprising the steps of setting a first target speed to be reached by the motor, determining whether the first target speed can be reached, and, if the first target speed can be reached, maintaining the first target speed until a set dose of medicine has been injected from the injection device, or if the first target speed cannot been reached, setting a second target speed.

Claims

1. A method for ensuring a constant target speed of a battery driven electrical motor, the battery driven electrical motor being adapted to move a piston rod in an injection device so as to inject a set dose of medicine from the injection device, the method comprising:

setting a first target speed to be reached by the piston rod,

determining whether the first target speed can be reached, and,

if the first target speed can be reached, maintaining the first target speed until the set dose of medicine has been injected from the injection device, or

if the first target speed cannot been reached, setting a second target speed.

2. The method according to claim 1, further comprising determining whether the second target speed can be reached, and

if the second target speed can be reached, maintaining the second target speed until the set dose of medicine has been injected from the injection device, or

if the second target speed cannot be reached, setting a third target speed.

3. The method according to claim 2, further comprising determining whether the third target speed can be reached, and, if the third target speed can be reached, maintaining the third target speed until the set dose of medicine has been injected from the injection device, or, if the third target speed cannot been reached, shutting down the motor.

4. The method according to claim 1, wherein the determining of the speed of the piston rod comprises measuring the speed of the motor.

5. The method according to claim 1, further comprising measuring the current provided to the motor.

6. The method according to claim 5, further comprising shutting down the motor if the current provided to the motor exceeds a predetermined value.

7. The method according to claim 3, wherein the first target speed is higher than a second target speed which is higher than a third target speed.

8. The method according to claim 1, further comprising generating a battery alarm signal when the second target speed is set, the battery alarm signal being provided to a control module of the injection device so as to warn the user of the device that the capacity of the battery is insufficient to reach the first target speed.

9. A system for carrying out the method according to claim 1, the system comprising:

an electrical motor operatively coupled to a direction sensitive encoded unit, and

a control module comprising a user interface, a microprocessor, a memory module, a motor controller and at least one A/D converter for converting an incoming analogue signal to the control module into a digital format.

11. A computer program product adapted to carry out the method according to claim 1 when said computer program product is run on a microprocessor.

10. An injection device for injecting a set dose of medicine from a medicine containing ampoule, the injection device comprising a system comprising:

an electrical motor operatively coupled to a direction sensitive encoded unit, and

a control module comprising a user interface a microprocessor, a memory module, a motor controller and at least one A/D converter for converting an incoming analogue signal to the control module into a digital format.