Injection device and assembly method

Patent metadata

Field	Value
Publication number	US-10201662-B2
Application number	US-201414782667-A
Country	US
Kind code	B2
Filing date	Apr 8, 2014
Priority date	Apr 10, 2013
Publication date	Feb 12, 2019
Grant date	Feb 12, 2019

Abstract

An injection device includes a housing containing a cartridge containing a medicament and a movable bung. The housing includes an inner thread. The injection device includes a piston rod for moving the bung during dose dispensing. The piston rod includes an outer thread engaging the inner thread of the housing a bearing at its end facing the bung. The injection device further includes a driver coupled to the piston rod for driving the piston rod during dose dispensing. In the unused delivery state of the device, the bearing abuts the bung. The invention further refers to an assembly method for such an injection device.

First claim

The invention claimed is:

1. An injection device comprising
a housing containing a cartridge containing a medicament and a movable bung, wherein the housing comprises an inner thread,
a piston rod for moving the bung during dose dispensing, the piston rod comprising an outer thread engaging the inner thread of the housing and a bearing facing the bung and positioned at a distal end of the piston rod, wherein, in an unused delivery state of the device, the bearing abuts the bung, and
a driver coupled to the piston rod for driving the piston rod during dose dispensing.

2. The injection device of claim 1 , wherein the driver comprises a drive tube directly coupled to the piston rod and a drive sleeve coupled to a power reservoir to drive the drive tube in a distal direction.

3. The injection device of claim 2 , wherein the power reservoir comprises a pre-loaded spring.

4. The injection device of claim 2 , wherein the drive tube and the drive sleeve are rotationally coupled to each other such that rotation of the drive tube in a first direction causes rotation of the drive sleeve in a second direction.

5. The injection device of claim 4 , wherein the drive tube and the drive sleeve are coupled to each other by meshing gears such that the drive tube and the drive sleeve rotate in opposite directions.

6. The injection device of claim 1 , further comprising a dose setting member, wherein the piston rod defines a first longitudinal axis and the dose setting member defines a second longitudinal axis parallel to and spaced apart from the first longitudinal axis.

7. The injection device of claim 6 , wherein:
the driver comprises a drive tube directly coupled to the piston rod and a drive sleeve coupled to a power reservoir to drive the drive tube in a distal direction,
the drive tube is rotatable about the first longitudinal axis, and
the drive sleeve is rotatable about the second longitudinal axis.

8. The injection device of claim 6 , wherein a portion of at least one of the dose setting member and the driver is axially displaceable along the second longitudinal axis between a dose setting position and a dose dispensing position,
wherein, in the dose setting position, the dose setting member is rotatable relative to the housing and relative to the driver, and
wherein, in the dose dispensing position, the driver is rotatable relative to the housing.

9. The injection device of claim 6 , further comprising:
a first spool located on the first longitudinal axis and a second spool located on the second longitudinal axis, one of the first spool and the second spool being coupled to the driver; and
a reverse wound flat spiral spring having a first end attached to the first spool and a second end attached to the second spool located on the second longitudinal axis.

10. The injection device of claim 6 , wherein:
the dose setting member comprises a dial assembly and a dial sleeve,
the dial assembly and the dial sleeve are rotatable about the second longitudinal axis, and
the dial assembly is decoupled from the driver during dose setting and is coupled to the driver during dose dispensing.

11. The injection device of claim 6 , further comprising a number sleeve in threaded engagement with the housing and in splined engagement with the dose setting member.

12. The injection device of claim 6 , comprising:
a limiter mechanism positioned with the housing to engage the dose setting member to define a maximum settable dose and a minimum settable dose, and
a last dose protection mechanism positioned within the housing for preventing the dose setting member from being set to an excess dose exceeding an amount of remaining medicament in the cartridge.

13. The injection device of claim 6 , wherein the dose setting member comprises a release button axially displaceable along a longitudinal axis of the injection device, wherein displacement of the release button in a first direction along the longitudinal axis increases a friction force on the driver, and displacement of the release button in a second direction along the longitudinal axis decreases the friction force on the driver.

14. The injection device of claim 1 , further comprising a release clutch preventing rotation of the driver relative to the housing during dose setting and allowing rotation of the driver relative to the housing during dose dispensing.

15. The injection device of claim 1 , wherein the piston rod is rotationally constrained to a portion of the driver and is axially displaceable relative to the portion of the driver.

16. The injection device of claim 1 , further comprising a clicker that produces an audible and/or tactile first feedback during dose setting and/or during dose dispensing.

17. The injection device of claim 16 , wherein the clicker comprises a protrusion and a flexible member, the protrusion and the flexible member being positioned such that the protrusion contacts the flexible member to produce the audible and/or tactile feedback.

18. The injection device of claim 16 , wherein the clicker is a first clicker, and the injection device further comprises a second clicker that produces an audible and/or tactile second feedback, distinct from the first feedback, during dose dispensing when the device reaches its minimum dose position.

19. The injection device of claim 1 , wherein a length of the injection device along a longitudinal axis of the injection device before dose setting is equal to a length of the injection device along the longitudinal axis of the injection device after dose setting.

Assignees

• Sanofi Sa

Inventors

• Morris Anthony Paul
• Marsh William
• Jones Matthew
• Butler Joseph
• Plumptre David Aubrey
• Veasey Robert

Classifications

• A61M5/3146

  Priming, e.g. purging, reducing backlash or clearance · CPC title

• A61M5/31541

  Means preventing setting of a dose beyond the amount remaining in the cartridge · CPC title

• A61M5/31583

  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 title

• A61M2207/00

  Methods of manufacture, assembly or production · CPC title

• A61M5/20

  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 title