Injection device

• US 20050209570A1
• Filed: 05/04/2005
• Published: 09/22/2005
• Est. Priority Date: 06/16/2000
• Status: Active Grant

• Current Assignee: Novo Nordisk A/S
• Original Assignee: Novo Nordisk A/S
• Inventors: Moller, Claus Schmidt
• Granted Patent: US 8,206,361 B2
• Time in Patent Office: Days
• US Class Current: 604/207
• CPC Class Codes: A61M 2005/3152 including gearings to multiply or attenuate the piston displacing force
• CPC Class Codes: A61M 2205/581 by audible feedback
• 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 5/28 Syringe ampoules or carpules, i.e. ampoules or carpules provided with a needle
• CPC Class Codes: A61M 5/315 Pistons; Piston-rods; Guiding, blocking or restricting the movement of the rod or piston; Appliances on the rod for facilitating dosing ; Dosing mechanisms
• CPC Class Codes: A61M 5/31541 Means preventing setting of a dose beyond the amount remaining in the cartridge
• CPC Class Codes: A61M 5/3155 by rotational movement of dose setting member, e.g. during setting or filling of a syringe
• CPC Class Codes: A61M 5/31551 including 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 5/31575 using scaling up or down transmissions, e.g. gearbox
• CPC Class Codes: A61M 5/3158 performed by axially moving actuator operated by user, e.g. an injection button

Abstract

An injection device for injection of set doses of medicine from a cartridge, in which syringe a dose is set by screwing a nut up along a threaded piston rod, whereby a dose setting drum, which carries on its cylindrical surface along a helix a scale of which a number corresponding to the set dose is shown in a window in the housing of the syringe, and an injection button, which is elevated over the end of the syringe, are moved axially a distance which is larger than the axial movement of the nut. A gear wheel transmission is established between the nut and the injection button.

Claims

1. A drive mechanism for use in a drug delivery device comprising

a housing (1) having a helical thread (6),

a dose dial sleeve (17) having a helical thread engaged with the helical thread of the housing (1),

a drive sleeve (20) releasable connected to the dose dial sleeve (17),

and a clutch means (21) located between the dose dial sleeve (17) and the drive sleeve (20), wherein,

a) when the dose dial sleeve (17) and the drive sleeve (20) are coupled, both are allowed to rotate with respect to the housing (1), and

b) when the dose dial sleeve (17) and the drive sleeve (20) are de-coupled, rotation of the dose dial sleeve (17) with respect to the housing (1) is allowed, while rotation of the drive sleeve (20) with respect to the housing (1) is not allowed, whereby axial movement of the drive sleeve is allowed so that a force is transferred in the longitudinal direction to the proximal end of the drug delivery device.

2. A drive mechanism according to claim 1, wherein a piston rod (4) is provided which is adapted to operate through the housing (1) and transfer the force in the longitudinal direction to the proximal end of the drug delivery device.

3. A drive mechanism according to claim 2, wherein the piston rod (4) is provided with a thread which is engaged by a nut (13) which is screwed along the threaded piston rod (4) away from a defined position in the housing (1) to set a dose and is pressed back to the defined position carrying the piston rod (4) with it to inject the set dose.

4. A drive mechanism according to claim 3, wherein a gearbox (9) having gear wheels and racks in permanent engagement is provided between the drive sleeve (2) and the nut (13) through which gearbox (9) rotation of the drive sleeve (20) is transmitted directly to the nut (13) causing the nut (13) to rotate and axial movement of the drive sleeve (20) relative to the housing (1) is transmitted to the nut (13) causing the nut (13) to move axially.

5. A drug delivery device according to claim 4 which is a pen-type injection device.

6. A drug delivery device according to claim 4 which comprises a needle.