Relating in and relating to an injection device

• US 20040087904A1
• Filed: 09/15/2003
• Published: 05/06/2004
• Est. Priority Date: 03/27/2001
• Status: Active Grant

• Current Assignee: Sanofi-Aventis Deutschland GmbH (Sanofi )
• Original Assignee: Dca Design International Ltd.
• Inventors: Plumptre, David Aubrey, Langley, Christopher Nigel, Woolston, Robert
• Granted Patent: US 7,985,201 B2
• Time in Patent Office: Days
• US Class Current: 604/131
• CPC Class Codes: A61M 2005/31518 designed to reduce the overall size of an injection device, e.g. using flexible or pivotally connected chain-like rod members
• CPC Class Codes: A61M 2005/3152 including gearings to multiply or attenuate the piston displacing force
• CPC Class Codes: A61M 5/20 Automatic syringes, e.g. with automatically actuated piston rod, with automatic needle injection, filling automatically A61M5/142 , A61M5/46 take precedence; hypodermic projectiles F42B12/54
• CPC Class Codes: A61M 5/24 Ampoule syringes, i.e. syringes with needle for use in combination with replaceable ampoules or carpules, e.g. automatic ampoules or carpules A61J1/06
• CPC Class Codes: A61M 5/31513 Piston constructions to improve sealing or sliding
• CPC Class Codes: A61M 5/31553 without axial movement of dose setting member
• CPC Class Codes: A61M 5/31558 using scaling up or down transmissions, e.g. gearbox
• CPC Class Codes: A61M 5/31561 using freely adjustable volume steps
• CPC Class Codes: A61M 5/31563 interacting with a displaceable stop member
• CPC Class Codes: A61M 5/31578 based on axial translation, i.e. components directly operatively associated and axially moved with plunger rod
• CPC Class Codes: A61M 5/31593 Multi-dose, i.e. individually set dose repeatedly administered from the same medicament reservoir

Abstract

Injection devices are known for the self administration of a medicament by patients in which the medicament is contained within a cartridge located within the injection device. It is a problem that such injection devices should be small enough to fit into a jacket pocket or a hand bag without difficulty. Concurrently, the injection device must be of size that enables a piston or similar used to drive a cartridge bung within the cartridge to be moved both to a maximum dispense position within the cartridge and to be fully withdrawn from the cartridge to allow for replacement of the cartridge. A drive mechanism for an injection device is disclosed comprising a piston member 10, a semi rigid belt 18 connected to the piston member 10, a belt drive means to selectively engage with the semi rigid belt 18 to drive the semi rigid belt 18, and a dose setting mechanism to control the selective engagement of the semi rigid belt in which the semi rigid belt 18 includes a track incorporated therein and the belt drive means comprises a tooth 50 for selective engagement with the track to drive the belt 18 only when there is relative movement between the semi rigid belt 18 and the tooth 50 in a first direction. An injection device comprising such a drive mechanism is also disclosed.

Claims

1. A drive mechanism for an injection device in which a piston is successively moved in relation to a first end of a medicament cartridge (6) containing a medicament selectively to drive a bung (8) closing a first end of the medicament cartridge (6) into the medicament cartridge (6) to expel medicament through a delivery member (4) located at a second end of the medicament cartridge, in which the drive mechanism comprises a piston member, a semi rigid belt (18) including a track incorporated therein connected to the piston member (10), a belt drive means to drive the semi rigid belt (18), and a dose setting mechanism to control the selective engagement of the semi rigid belt (18) is characterised in that the belt drive means selectively engages with the semi rigid belt (18) and in that the belt drive means comprises a tooth (50) for selective engagement with the track to drive the belt only when there is relative movement between the semi rigid belt (18) and the tooth (50) in a first direction.

2. A drive mechanism for an injection device according to claim 1, characterised in that the belt drive means further comprises an inner gear (20) adapted to engage with the track in the semi rigid belt (18) and be driven by movement of the track in the first direction.

3. A drive mechanism according to either claim 1 or claim 2, characterised in that the belt drive means further comprises a flexible member (52) to carry the tooth (50), a second piston member (34) to carry the flexible member (52) and a charge means to drive the belt drive means in the first direction.

4. A drive mechanism according to claim 3, characterised in that the charge means comprises a spring (12).

5. A drive mechanism according to claim 3 or claim 4, characterised in that the second piston member (34) includes a biased dose button (44) adapted releasably to retain a dosing spindle (34) in a desired position.

6. A drive mechanism for an injection device according to claim 2, characterised in that the dose setting mechanism comprises a dial dose means (42), a dosing spindle (38), an outer gear (22), an outer gear drive means located between the spindle (38) and the outer gear (22), a plurality of intermediate gears (24) interposed between the inner gear (20) and the outer gear (22), and a dose trip peg (26) carried by one of the plurality of intermediate gears (24) to control the selective engagement of the semi rigid belt (18).

7. A drive mechanism for an injection device according to claim 5, characterised in that the dose setting mechanism further comprises displacement means to displace the dosing spindle (38).

8. A drive mechanism for an injection device according to any previous claim, characterised in that the semi rigid belt (18) and the piston member (10) are formed as a unitary component.

9. An injection device having a housing, characterised in that the device further comprises a drive mechanism according to any previous claim.

10. An injection device according to claim 9, characterised in that the displacement means comprises a button (54) located for displacement within the housing (2) of the injection device.

11. An injection device according to either claim 9 or claim 10, characterised in that the housing has an aperture for cooperation with a or the dose button (44).