Auto-injector

Patent metadata

Field	Value
Publication number	US-10384016-B2
Application number	US-201213983805-A
Country	US
Kind code	B2
Filing date	Feb 16, 2012
Priority date	Feb 18, 2011
Publication date	Aug 20, 2019
Grant date	Aug 20, 2019

Abstract

An auto-injector for administering a dose of a liquid medicament (M) is presented having an elongate case, a carrier subassembly comprising a tubular carrier slidably arranged inside the case, where the carrier adapted to contain a syringe with a hollow injection needle. The injector also has, a drive spring and a plunger for forwarding load of the drive spring to a stopper of the syringe, wherein the syringe is lockable for joint axial translation with the carrier. A control spring is arranged around the carrier for translating the carrier in a proximal direction (P) for advancing the needle beyond a proximal end of the auto-injector, and a trigger button is used for releasing the control spring on actuation.

First claim

The invention claimed is:

1. An auto-injector for administering a dose of a liquid medicament (M), comprising:
an elongate case,
a carrier subassembly comprising a tubular carrier slidably arranged inside the case, the carrier comprising a drive spring and a plunger for forwarding load of the drive spring to a stopper of a syringe with a hollow injection needle lockable for joint axial translation with the carrier,
a control spring arranged around the carrier for translating the carrier in a proximal direction (P) for advancing the needle beyond a proximal end of the auto-injector,
a trigger button for releasing the control spring on actuation,
wherein the drive spring biases the plunger in the proximal direction (P) against the carrier, wherein at least one resilient arm is arranged on either the carrier or the plunger and in a ramped engagement to the other of the carrier or the plunger so as to disengage them under load of the drive spring, wherein a peg is arranged to be coupled to the case at least after actuation of the trigger button so as to be positioned to support the resilient arm preventing disengagement of the carrier from the plunger and thus release of the drive spring when the carrier is in a distal position, wherein the peg is arranged to remain in position when the carrier is translated for advancing the needle so as to pull the resilient arm away from the peg thus allowing deflection of the resilient arm due to the ramped engagement under load of the drive spring for disengaging the plunger from the carrier and releasing the drive spring for drug delivery when the carrier has reached a predefined position during needle advance, wherein a portion of the peg that is positioned to support the resilient arm preventing disengagement of the carrier from the plunger and thus release of the drive spring when the carrier is in the distal position protrudes into the case.

2. The auto-injector according to claim 1 , wherein the control spring is released by activating a needle insertion control mechanism for coupling a proximal end of the control spring to either the carrier or to a chassis.

3. The auto-injector according to claim 2 , wherein the proximal end of the control spring is coupled to the carrier, wherein the needle insertion control mechanism is adapted to decouple the proximal end of the control spring from the carrier and to couple the proximal end of the control spring to the chassis for needle retraction depending on the relative axial position of the carrier and the chassis.

4. The auto-injector according to claim 2 , wherein the needle insertion control mechanism comprises a first collar biased by the control spring in a proximal direction (P), wherein at least one resilient beam is proximally arranged on the first collar, wherein respective recesses are arranged in the carrier and case, wherein a transversal extension of a head of the resilient beam is wider than a gap between the carrier and the chassis causing the head of the resilient beam to abut a distal face on the recess in the chassis while being prevented from deflecting in an inward direction (I) by the carrier or to abut a distal face on the recess in the carrier while being prevented from deflecting in an outward direction (O) by the chassis thereby forwarding load from the control spring to the carrier for needle insertion, wherein the resilient beam is arranged to be switched between the chassis and the carrier by ramped engagement of the head to the distal faces under load of the control spring depending on the relative longitudinal position between the chassis and the carrier.

5. The auto-injector according to claim 2 , wherein the proximal end of the control spring is coupled to the chassis, wherein the trigger button is operatively connected to the needle insertion control mechanism, so that actuation of the trigger button decouples the proximal end of the control spring from the chassis and couples the proximal end of the control spring to the carrier.

6. The auto-injector according to claim 1 , wherein the trigger button is operatively connected to a detent mechanism that is arranged to provide a resistive force which has to be overcome to advance the carrier in the proximal direction (P) for needle insertion.

7. The auto-injector according to claim 6 , wherein the detent mechanism is arranged to provide a resistive force resisting translation of the carrier in the distal direction (D) relative to a chassis for keeping the carrier in a defined position in a transitional state with both ends of the control spring decoupled from the carrier.

8. The auto-injector according to claim 6 , wherein the detent mechanism comprises a resilient beam on the chassis and a rhomboid ramp member on the carrier, the resilient beam being essentially straight when relaxed and having a first beam head arranged to interact in a ramped engagement with a proximal first ramp or a distal second ramp on the rhomboid ramp member in such a manner that application of a translative force on the carrier relative to the chassis in the proximal direction (P) with the first beam head engaged to the fourth ramp deflect the resilient beam in one transversal direction when a predetermined value of the translative force, at least depending on the resilience of the resilient beam, is overcome so as to allow the first beam head to travel along one transversal side of the rhomboid ramp member on continued relative translation of the components, wherein the resilient beam is allowed to relax when the first beam head has reached a fifth ramp thereby engaging it in a manner that application of a translative force on the carrier in the distal direction (D) deflects the resilient beam in the other transversal direction when a predetermined value of the translative force, at least depending on the resilience of the resilient beam, is overcome so as to allow the first beam head to travel along the other transversal side of the rhomboid ramp member on continued translation of the carrier.

9. The auto-injector according to claim 6 , wherein the case is arranged to lock the detent mechanism prior to being translated in the proximal direction (P) relative to the chassis, wherein the case when translated into an advanced position in the proximal direction (P) is arranged to unlock the detent mechanism rendering it operable.

10. The auto-injector according to claim 1 , wherein a syringe retraction control mechanism is arranged for coupling a distal end of the control spring to either the carrier for needle retraction or to the case otherwise.

11. The auto-injector according to claim 10 , wherein the syringe retraction control mechanism comprises a collar bearing against the distal end of the control spring and having a resilient proximal beam with a beam head having an inward boss, wherein the beam head is arranged to be in a ramped engagement with a case detent in the case in a manner ramping the beam head in an inward direction (I) under load of the control spring in the distal direction (D), wherein the inward boss is arranged to inwardly abut the carrier for preventing inward deflection of the beam head and keep the collar locked to the case, wherein a recess is arranged in the carrier for allowing the inward boss to be inwardly deflected on translation of the case in the distal direction (D) relative to the carrier on removal of the auto-injector from the injection site.

12. The auto-injector according to claim 1 , wherein a releasable noise component is provided, capable of, upon release, generating an audible or tactile feedback, wherein the noise component is arranged to be released when the plunger reaches a position relative to the syringe in whi

Assignees

• Brereton Simon Francis
• Kemp Thomas
• Burnell Rosie
• Ekman Matthew
• Sanofi Aventis Deutschland

Inventors

• Brereton Simon Francis
• Kemp Thomas
• Burnell Rosie
• Ekman Matthew

Classifications

• A61M2005/206

  With automatic needle insertion · CPC title

• F04C2270/0421

  Controlled or regulated · CPC title

• A61M5/5086

  for indicating if defective, used, tampered with or unsterile · 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

• Y10T403/32501

  Cam or wedge · CPC title