Syringe Device With a Dose Limiting Mechanism and an Additional Safety Mechanism

• US 20080234634A1
• Filed: 07/17/2006
• Published: 09/25/2008
• Est. Priority Date: 07/27/2005
• Status: Active Grant

• Current Assignee: Novo Nordisk A/S
• Original Assignee: Novo Nordisk A/S
• Inventors: Markussen, Tom Hede, Moller, Claus Schmidt, Enggaard, Christian Peter, Eiland, Jacob
• Granted Patent: US 10,220,155 B2
• Time in Patent Office: Days
• US Class Current: 604/208
• 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 5/31541 Means preventing setting of a dose beyond the amount remaining in the cartridge
• 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 5/31573 Accuracy improving means
• CPC Class Codes: A61M 5/31583 based on rotational translation, i.e. movement of piston rod is caused by relative rotation between the user activated actuator and the piston rod
• CPC Class Codes: A61M 5/31593 Multi-dose, i.e. individually set dose repeatedly administered from the same medicament reservoir

Abstract

A syringe device for ejecting a dose of a medicament, the syringe device comprising: a dose limiting mechanism arranged to interact with a dose ejecting mechanism to prevent ejection of a dose exceeding a set dose, and a safety mechanism, which is arranged such with respect to the dose ejecting mechanism that, if the dose limiting mechanism fails, the safety mechanism prevents ejection of a dose exceeding the set dose.

Claims

1. A syringe device for ejecting a dose of a medicament, the syringe device comprising:

a housing;

a dose ejecting mechanism comprising;

a dose setting member being rotatable in relation to the housing so as to set a dose to be ejected,

a piston rod arranged with respect to the housing such that translational movement of the piston rod in a distal direction causes the dose to be ejected,

means for transforming translational movement of the dose setting member into translational movement of the piston rod;

a dose limiting mechanism arranged to interact with the dose ejecting mechanism to prevent ejection of a dose exceeding the set dose; and

a safety mechanism, which is arranged such with respect to the dose ejecting mechanism that, if the dose limiting mechanism fails, the safety mechanism prevents ejection of a dose exceeding the set dose.

2. A syringe device according to claim 1, wherein the housing defines a passage for the piston rod, the passage having a threaded inner surface for engagement with a threaded outer surface of the piston rod, the piston rod being arranged with respect to the housing such that rotation of the piston rod relative to the housing causes the piston rod to be displaced translationally relative to the housing.

3. A syringe device according to claim 1, wherein at least one of the dose limiting mechanism and the safety mechanism is adapted to limit relative rotational movement between the piston rod and the housing, to a rotation corresponding to ejection of the set dose.

4. A syringe device according to claim 1, wherein the dose limiting mechanism comprises a first stopping surface adapted to engage a corresponding second stopping surface of the housing, and wherein rotation of the dose setting member during dose setting causes the first stopping surface to move away from the second stopping surface and wherein ejection of a dose is prevented when the first stopping surface abut the second stopping surface.

5. A syringe device according to claim 4, wherein the dose setting member comprises the first stopping surface.

6. A syringe device according to claim 4, wherein the dose setting member is coupled to a cylinder comprising the first stopping surface, said cylinder being adapted to indicate the set dose.

7. A syringe device according to claim 1, wherein the safety mechanism comprises:

a limiter defining a passage for the piston rod, the passage of the limiter defining a threaded inner surface for engagement with the threaded outer surface of the piston rod; and

a driver defining a passage for the limiter, the driver being rotationally retained in relation to the limiter, the driver being coupled to the dose setting member such that rotation of the dose setting member during dose setting causes the driver to rotate;

wherein relative rotation between the drive and the piston rod during dose setting causes the limiter to move away from a stopping position wherein the limiter prevents ejection of a dose.

8. A syringe device according to claim 1, further comprising an ejection assisting system for providing an ejection force for assisting an operator of the device in forcing the piston in the distal direction so as to eject the set dose.

9. A syringe device according to claim 8, wherein the ejection assisting system comprises a spring which is arranged to rotate the driver relative to the housing.

10. A syringe device according to claim 9, wherein the spring is prestrained when limiter is in the stopping position.