Injection device

• US 8,202,256 B2
• Filed: 06/20/2007
• Issued: 06/19/2012
• Est. Priority Date: 06/16/2000
• Status: Expired due to Term

• Current Assignee: Novo Nordisk A/S
• Original Assignee: Novo Nordisk A/S
• Inventors: Moller, Claus Schmidt
• Primary Examiner(s): STIGELL, THEODORE J
• Application Number:
  US11/765,789
• Publication Number:
  US 20070244445A1
• Time in Patent Office: 1,826 Days
• Field of Search: 604/181, 604/187, 604207-211, 604/218
• 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

A medication dispensing device with a housing and a member wherein the member is moveable in a distal direction is useful in delivering medication to a patient. A fluid container can be used with the device and often has a moveable piston at one end and an outlet at the other. The member receives a force from a user and drives the piston in the distal direction to expel medication. A intermediate system is disposed between the member and the piston including a gear set that has a pinion in meshed engagement with a rack. The system allows the member to move a greater distance than the piston moves thereby increasing the force on the piston.

Claims

1. An injection device for injecting a dose of medication from a cartridge having a piston at one end and a membrane at an opposite end, the device comprising:

a. a distal end from which medication can be expelled;

b. an axially displaceable element that moves in a proximal direction during dose setting and that receives a force from user that is directed in a distal direction during injection;

c. a piston drive element for engaging and moving the piston within the cartridge in a distal direction to expel medication from the cartridge;

a gearing coupling the axially displaceable element with the piston drive element, the gearing increasing the force exerted by the user on the axially displaceable element so that a greater force is exerted on the piston drive element, the gearing comprising a first rack that is connected to the axially displaceable element, the first rack being in continuous meshed engagement with a pinion gear wheel during dose setting and injection of a dose, wherein the gearing causes the piston drive element to move a distance in a distal direction during injection that is less than the distance moved by the first rack, wherein the pinion gear wheel moves distally during injection of medication from the cartridge.

2. The device of claim 1, wherein the gearing causes the piston drive to move half the distance that the axially displaceable element moves during injection of a dose.

3. An injection device for injecting a dose of medication from a cartridge having a piston at one end and a membrane at an opposite end, the device comprising:

a. an axially displaceable element that moves in a first direction during dose setting and that receives a force from user that is directed in an opposite, second direction during injection;

b. a piston drive element for engaging and moving the piston within the cartridge in the second direction to expel medication from the cartridge during injection

c. a transmission assembly coupling the axially displaceable element with the piston drive element, the transmission assembly comprising;

i. a first rack that moves axially in the first and second direction with the axially displaceable element;

ii. a pinion in continuous meshed engagement with the rack during motion of the rack in both the first and second directions;

iii. a second pinion that rotates in unison with the first pinion during injection of a dose;

iv. a transmission output connection member that connects at least the second pinion and the piston drive and that drives the piston drive to move a distance less than the distance the first rack moves,

wherein the pinion gear wheel moves distally during injection of medication from the cartridge.

4. An injection device for injecting a dose of medication from a cartridge having a piston at one end and a membrane at an opposite end, the device comprising:

an axially displaceable element that moves in a proximal direction during dose setting and that receives a force from user that is directed in a distal direction during injection;

a piston drive element for engaging and moving the piston within the cartridge in a distal direction to expel medication from the cartridge;

a rack and pinion assembly connecting the axially displaceable element to the piston drive element, the rack and pinion assembly comprising;

a first rack that moves distally and proximally with the axially displaceable element;

a first pinion in continuous meshed engagement with the first rack during both dose setting and injection;

a second rack that is in continuous meshed engagement with a second pinion; and

wherein the gearing in the rack and pinion assembly causes the piston drive to move a shorter distance than the axially displaceable element during injection thereby resulting in an increased force on the piston drive as compared to the force exerted on the axially displaceable member,

wherein the pinion gear wheel moves distally during injection of medication from the cartridge.

5. An injection device comprising:

an injection button that moves forward during injection and backward during setting of a dose to be injected

a piston drive for moving a piston within a medication cartridge to expel medication from the cartridge;

a transmission that transmits force from the injection button, to the piston drive, one portion of the transmission physically connected to the injection button and an other portion of the transmission physically connected to the piston drive, the transmission further comprising;

a first rack that moves forward and backwards with the injection button;

a first pinion in continuous meshed engagement with the first rack during both backward and forward motion;

a second rack in continuous meshed engagement with a second pinion, and wherein the first and second pinions have different diameters and wherein they rotate during injection at the same rotational speed thereby creating a mechanical advantage that results in the transmission driving the piston drive a distance that is less than the distance a user drives the injection button during injection of a dose of medication,

wherein the pinion gear wheel moves distally during injection of medication from the cartridge.