Medicament delivery device

• US 7,695,456 B2
• Filed: 01/22/2003
• Issued: 04/13/2010
• Est. Priority Date: 01/25/2002
• Status: Active Grant

• Current Assignee: Sanofi-Aventis Deutschland GmbH (Sanofi )
• Original Assignee: Dca Design International Ltd.
• Inventors: Veasey, Robert Frederick, Langley, Christopher Nigel
• Primary Examiner(s): Lucchesi; Nicholas
• Assistant Examiner(s): Bouchelle; Laura A
• Application Number:
  US10/347,634
• Publication Number:
  US 20030158524A1
• Time in Patent Office: 2,638 Days
• Field of Search: 604/218, 604/68, 604/69, 604/70, 604/97.02, 604/187, 604/223, 604/243, 604/207, 604/211, 604/131, 604/152, 604/35, 604/37, 604/151, 411/14, 737/61
• US Class Current: 604/218
• CPC Class Codes: A61M 2202/00 Special media to be introduced, removed or treated
• CPC Class Codes: A61M 2202/04 Liquids
• CPC Class Codes: A61M 2205/50 with microprocessors or computers
• CPC Class Codes: A61M 2205/8206 battery-operated
• CPC Class Codes: A61M 5/14566 with a replaceable reservoir for receiving a piston rod of the pump
• 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

Abstract

The present invention relates to a medicament delivery device such as a pen type injector used to expel medicament from a medicament cartridge under the action of a lead screw. The medicament cartridge typically comprises a cylinder having a displaceable piston at one end displacement causing medicament contained within the cartridge to be expelled. It is of advantage to know when the plunger contacts the displaceable piston since no delivery of medicament can occur before this point. A delivery device is disclosed in which a lead screw for a medicament delivery device comprises a shaft portion and a head portion, the head portion further comprising a fixed part, a displaceable part movable with respect to the fixed part, biasing means acting normally to urge the displaceable part away from the fixed part and a sensor to detect when the displaceable part moves towards the fixed part, one of the fixed part and the displaceable part being provided with a plurality of resilient fingers extending axially with respect to the lead screw, and the other of the fixed part and the displaceable part being provided with a plurality of opening, each of the resilient fingers extending within a corresponding opening.

Claims

1. A lead screw for a medicament delivery device, comprising:

a shaft portion; and

a head portion, the head portion further comprising;

a fixed part,

a displaceable part movable with respect to the fixed part,

biasing means acting normally to urge the displaceable part away from the fixed part, and

a position sensor to detect when the displaceable part moves towards the fixed part, in which one of the fixed is provided with a plurality of resilient fingers extending axially with respect to a longitudinal axis of the lead screw, and displaceable part is provided with a plurality of openings, each of the resilient fingers extending within a corresponding opening.

2. A lead screw according to claim 1, in which the biasing means is incorporated within the sensor.

3. A lead screw according to claim 2, in which between each of the plurality of resilient fingers there are located a plurality of axially extending channels, and the displaceable part is provided with a plurality of projecting parts for sliding engagement within the channels.

4. A lead screw according to claim 1, in which between each of the plurality of resilient fingers there are located a plurality of axially extending channels, and the displaceable part is provided with a plurality of projecting parts for sliding engagement within the channels.

5. A lead screw according to claim 1, in which each of the resilient fingers is provided with a radially outward extending tab.

6. A lead screw according to claim 1, in which the shaft portion of the lead screw is provided with a groove along its length.

7. A lead screw according to claim 6, in which the sensor further comprises a lead extending from the sensor along the shaft portion of the lead screw within the groove.

8. A medicament delivery device comprising a drive means by which a lead screw in accordance with claim 1 can be advanced in use to cause a medicament to be expelled from the medicament delivery device.

9. A lead screw for a medicament delivery device, comprising:

a shaft portion; and

a head portion, the head portion further comprising;

a fixed part,

a displaceable part movable with respect to the fixed part,

biasing means acting normally to urge the displaceable part away from the fixed part, and

a position sensor to detect when the displaceable part moves towards the fixed part, in which one of the fixed part and the displaceable part is provided with a plurality of resilient fingers extending axially with respect to a longitudinal axis of the lead screw, and the other of the fixed part and the displaceable part is provided with a plurality of openings, each of the resilient fingers extending within a corresponding opening.

10. A lead screw according to claim 9, in which the biasing means is incorporated within the sensor.

11. A lead screw according to claim 10, in which between each of the plurality of resilient fingers there are located a plurality of axially extending channels, and the other of the fixed part and the displaceable part is provided with a plurality of projecting parts for sliding engagement within the channels.

12. A lead screw according to claim 9, in which between each of the plurality of resilient fingers there are located a plurality of axially extending channels, and the other of the fixed part and the displaceable part is provided with a plurality of projecting parts for sliding engagement within the channels.

13. A lead screw according to claim 9, in which each of the resilient fingers is provided with a radially outward extending tab.

14. A lead screw according to claim 9, in which the shaft portion of the lead screw is provided with a groove along its length.

15. A lead screw according to claim 14, in which the sensor further comprises a lead extending from the sensor along the shaft portion of the lead screw within the groove.

16. A medicament delivery device comprising a drive means by which a lead screw in accordance with claim 9 can be advanced in use to cause a medicament to be expelled from the medicament delivery device.