Injection Device

• US 20070244445A1
• Filed: 06/20/2007
• Published: 10/18/2007
• Est. Priority Date: 06/16/2000
• Status: Active Grant

• Current Assignee: Novo Nordisk A/S
• Original Assignee: Novo Nordisk A/S
• Inventors: Moller, Claus
• Granted Patent: US 8,202,256 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

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 moveable piston at one end and a pierceable 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 a piston within a medication 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 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.

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 moveable piston at one end and a pierceable 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 a piston within a medication 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.

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

d. 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;

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

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

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

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

iii. a second rack that is in continuos meshed engagement with a second pinion; and

iv. 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.

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.

6. A method for expelling medication form an injection device having a rack and pinion transmission that couples an injection button with a piston driver;

the method comprising the steps of;

moving a first rack reward during setting of a dose, the rack remaining in continuous meshed engagement with a pinion causing that to rotate during setting of the dose;

moving the first rack forward during injection of a dose and causing the pinion to rotate in an opposite direction, thereby causing part of the transmission to drive the piston driver forward which in turn moves a piston within a medication cartridge and expels medication from the device.

9. A medication delivery device comprising:

a tubular dose setting element and a tubular dose injecting element for transmitting a force thru the device toward an injecting end, wherein during dose setting the dose setting element and dose injecting element are coupled so that one cannot move independently of the other and wherein during injection they are decoupled so that the dose setting element rotates to a zero position while the dose injecting element moves axially without rotating and the dose setting element follows the axial movement of the dose injecting element and wherein the injecting element is coupled to the piston rod in a manner that multiplies the force exerted on the piston rod.

7. The method of claim 6, further comprising the step of:

rotating a second smaller pinion at the same speed as the pinion of claim 10 during the expelling of the medication,

wherein the second pinion is in continuous meshed engagement with a second rack.

8. The method of claim 7, wherein the first rack moves forward by a distance greater than the piston is drive forward during injection.

10. The device of claim 9 wherein the injecting element is coupled to the piston rod via a gearing.

11. The device of claim 10, wherein the gearing comprises a round gear wheel and a toothed rack.