Front end for an auto-injector

Patent metadata

Field	Value
Publication number	US-9295785-B2
Application number	US-201113996044-A
Country	US
Kind code	B2
Filing date	Dec 21, 2011
Priority date	Dec 21, 2010
Publication date	Mar 29, 2016
Grant date	Mar 29, 2016

Abstract

The invention relates to a front end for an auto-injector, the front end comprising a syringe with an injection needle and a stopper, wherein the syringe is slidably arranged within a syringe retainer, wherein an outer sleeve for preventing access to the needle is removably arrangeable over the syringe retainer, wherein the syringe retainer comprises a screw thread for connecting it to a correspondent screw thread of a mounting of a re-usable auto-injector back end comprising a drive means for advancing the syringe and needle in a proximal direction for needle insertion and for advancing the stopper within the syringe for injection, wherein a resilient locking barb is arranged to rotationally lock the syringe retainer to the mounting in an unscrewing direction when the front end is screwed to the re-usable back end and when the outer sleeve is removed, wherein the outer sleeve is arranged to unlock the resilient locking barb when arranged over the syringe retainer.

First claim

The invention claimed is:

1. A front end for an auto-injector, the front end comprising: a syringe with an injection needle and a stopper, wherein the syringe is slidably arranged within a syringe retainer, wherein an outer sleeve for preventing access to the needle is removably arrangeable over the syringe retainer, wherein the syringe retainer comprises a screw thread for connecting it to a correspondent screw thread of a mounting of a re-usable auto-injector back end comprising a drive means for advancing the syringe and needle in a proximal direction for needle insertion and for advancing the stopper within the syringe for injection, wherein a resilient locking barb is arranged on the syringe retainer proximally from the screw thread of the syringe retainer, wherein the resilient locking barb is arranged to rotationally lock the syringe retainer to the mounting in an unscrewing direction when the front end is screwed to the re-usable back end and when the outer sleeve is removed, and the resilient locking barb exhibits a chamfer for inwardly deflecting the resilient locking barb by an internal surface of the mounting when rotated in a screwing direction, wherein the outer sleeve is arranged to unlock the resilient locking barb when arranged over the syringe retainer, the resilient locking barb being arranged to partially remain outside of the mounting so as to allow the outer sleeve to inwardly deflect the locking barb to unlock it, and wherein the resilient locking barb is arranged to engage an internal groove arranged in the mounting.

2. The front end according to claim 1 , wherein the syringe is arranged within an elongate housing telescoped within the syringe retainer, wherein the housing is biased in the proximal direction and arranged to be translated in a distal direction when applied against an injection site, and wherein a distal end of the housing is arranged to protrude towards the re-usable back end to indicate its longitudinal position to the re-usable back end.

3. The front end according to claim 2 , wherein the housing is arranged to protrude toward the re-usable back end to enable activation of a trigger mechanism of the re-usable back end, the trigger mechanism being coupled to the drive means such that the activation of the trigger mechanism enables release of the drive means for advancing the syringe and the needle and for advancing the stopper.

4. The front end according to claim 3 , wherein the trigger mechanism comprises a trigger button coupled to the drive means such that manual actuation of the trigger button triggers the release of the drive means.

5. The front end according to claim 2 , further comprising a cover retainer clip arranged in the outer sleeve extending distally and inwardly at an angle, wherein the cover retainer is inwardly biased so as to engage an outward surface of the housing in an initial state and during removal of the outer sleeve, wherein the cover retainer is arranged to deflect inwards when having travelled beyond a proximal end of the housing such that the cover retainer is deformed when the outer sleeve is reapplied to the housing in a manner opposing removal of the outer sleeve after reapplication.

6. The front end according to claim 2 , further comprising at least one transfer spring arranged as a resilient part integrally moulded with the housing for biasing the housing in the proximal direction against the syringe retainer.

7. The front end according to claim 1 , further comprising a protective needle sheath removably arrangeable over the needle, wherein the protective needle sheath is attached to the outer sleeve so as to be removed from the needle on removal of the outer sleeve from the syringe retainer.

8. The front end according to claim 7 , wherein the outer sleeve is attached to the protective needle sheath by a push fit or bump or snap fit or glued or ultrasonic welded.

9. The front end according to claim 7 , further comprising a star washer arranged over an external diameter of the protective needle sheath and outwardly engaged to an internal diameter of the outer sleeve.

10. The front end according to claim 7 , wherein: the syringe is arranged within an elongate housing telescoped within the syringe retainer, wherein the housing is biased in the proximal direction and arranged to be translated in a distal direction when applied against an injection site, the protective needle sheath has an external profiled structure in the shape of a finger grip, wherein the outer sleeve has at least two profiled arms extending in the distal direction from a proximal end face of the outer sleeve, the profiled arms are engaged to the profiled structure of the protective needle sheath, and the housing is arranged to outwardly support the profiled arms when the outer sleeve is attached to the syringe retainer such that the profiled arms are prevented from deflecting outwards.

11. The front end according to claim 7 , wherein the outer sleeve has at least one distal snap engaged distally behind a distal edge or shoulder of the protective needle sheath.

12. The front end according to claim 1 , further comprising a syringe lock arranged for preventing translation of the syringe from a distal position in the proximal direction when the outer sleeve is arranged over the syringe retainer.

13. The front end according to claim 1 , wherein the syringe is arranged in a syringe carrier arranged to support the syringe at its proximal end, the syringe carrier is tubular, and the syringe carrier is slidably arranged in the syringe retainer.

14. The front end according to claim 12 , wherein: the syringe is arranged in a syringe carrier arranged to support the syringe at its proximal end, the syringe carrier is tubular, and the syringe carrier is slidably arranged in the syringe retainer, the syringe lock comprises a hub extending through a lateral aperture in the syringe retainer in a manner to engage a finger flange of the syringe or a second shoulder on a distal end of the syringe carrier, the hub is outwardly biased so as to disengage the finger flange or second shoulder, and the outer sleeve is arranged to outwardly support the hub so as to prevent outward deflection and disengagement of the syringe lock.

15. The front end according to claim 1 , further comprising a syringe spring arranged to bias the syringe in a distal direction.

16. The front end according to claim 1 , wherein the outer sleeve surrounds the syringe retainer when the outer sleeve is arranged over the syringe retainer.

17. The front end according to claim 1 , wherein the outer sleeve is removed from the front end by being pulled in the proximal direction off the front end.

18. The front end according to claim 1 , wherein, when the resilient locking barb is engaged to the internal groove, the internal groove prevents rotation of the syringe retainer relative to the mounting in the unscrewing direction.

19. The front end according to claim 1 , wherein the syringe retainer comprises an engagement element positioned proximal from the resilient locking barb, the engagement element of the syringe retainer configured to engage an engagement element of the outer sleeve such that the syringe retainer and the outer sleeve jointly rotate when the outer sleeve is arranged over the syringe retainer.

20. The front end according to claim 1 , wherein the drive means comprises a drive spring configured to engage the syringe and the stopper.

Assignees

• Ekman Matthew
• Kemp Thomas
• Jennings Douglas A
• Sanofi Aventis Deutschland

Inventors

• Ekman Matthew
• Kemp Thomas
• Jennings Douglas A

Classifications

• A61M5/20 Primary

  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

• A61M5/3202

  Devices for protection of the needle before use, e.g. caps (A61M5/50 takes precedence; for infusion spikes A61M5/1626; protectors for sharps A61B50/3001) · CPC title

• A61M2005/2013

  triggering of discharging means by contact of injector with patient body · CPC title

• A61M5/3213 Primary

  Caps placed axially onto the needle, e.g. equipped with finger protection guards (axially-extensible protective sleeves A61M5/3243) · CPC title

• A61M5/31571

  Means preventing accidental administration (for automatic syringes A61M5/20) · CPC title