Auto-injector with injection damper

Patent metadata

Field	Value
Publication number	US-9233215-B2
Application number	US-201113806965-A
Country	US
Kind code	B2
Filing date	Jun 20, 2011
Priority date	Jun 28, 2010
Publication date	Jan 12, 2016
Grant date	Jan 12, 2016

Abstract

An auto-injector comprising an elongate housing arranged to contain a syringe and displacing medicament, wherein the syringe is slidably arranged with respect to the housing, spring capable of: pushing a needle from a covered position inside the housing into an advanced position, operating the syringe to supply a dose of medicament, and retracting the syringe with the needle into the covered position. Activating means is arranged to lock the spring in a pressurized state prior to manual operation and capable of, upon manual operation, releasing the spring for injection. The spring is a single drive spring arranged for advancing the needle and for injecting the dose of medicament via a plunger. A damper is arranged with the plunger by a spline so as to cause rotation of either the plunger or the damper at least during part of a translation of the plunger in proximal direction.

First claim

The invention claimed is:

1. An auto-injector for administering a dose of a liquid medicament, comprising:
an elongate main body arranged to contain a syringe with a hollow needle and a stopper for sealing the syringe and displacing the medicament, the main body having a distal end and a proximal end with an orifice intended to be applied against an injection site, wherein the syringe is slidably arranged with respect to the main body,
a spring capable of, upon activation:
pushing the needle from a covered position inside the main body into an advanced position through the orifice and past the proximal end,
operating the syringe to supply the dose of medicament, and
retracting the syringe with the needle into the covered position after delivering the medicament,
a trigger arranged to lock the spring in a pressurized state prior to manual operation and capable of, upon manual operation, releasing the spring for injection,
wherein the spring comprises a single drive spring in the shape of a compression spring arranged to be grounded at a distal end in the main body for advancing the needle and for injecting the dose of medicament via a plunger and
wherein the drive spring is arranged to have its ground in the main body switched to its proximal end for retracting the syringe,
further comprises a damper arranged around the plunger,
wherein the damper is engaged with the plunger by a spline
so as to cause rotation of either the plunger or the damper at least during part of a translation of the plunger in proximal direction and share the load of the drive spring between the translation and the rotation.

2. The auto-injector according to claim 1 , characterized in that the damper and plunger are arranged to cause rotation only during operation of the syringe to supply the dose of medicament.

3. The auto-injector according to claim 1 , characterized in that the plunger is prevented from rotating and that the damper is arranged to rotate, wherein a proximal face of the damper is arranged to abut against a distal face of a syringe holder arranged for joint axial translation with the syringe.

4. The auto-injector according to claim 3 , characterized in that a ratchet feature is arranged on the syringe holder or on the damper.

5. The auto-injector according to claim 3 , characterized in that at least one of the mating faces of the syringe holder or the damper comprises rubber.

6. The auto-injector according to claim 1 , characterized in that a pitch of the spline varies over the length of the spline.

7. The auto-injector according to claim 1 , characterized in that an activating means is arranged as a trigger button in the shape of a wrap- over sleeve button arranged over the distal end of the auto-injector, the trigger button extending at least almost over the whole length of the auto-injector, wherein the trigger button is arranged to release the drive spring upon translation in proximal direction.

8. The auto-injector according to claim 7 , characterized in that at least one clip is arranged in the main body, wherein the sleeve of the trigger button has a locking section with a reduced diameter arranged to prevent the clip from flexing outwards in the as delivered configuration, wherein the clip is arranged to lock the drive spring in the as delivered configuration, wherein the clip is arranged to be unlocked under load of the drive spring by flexing outwards when the trigger button and the locking section are translated in proximal direction.

9. The auto-injector according to claim 1 , characterized in that an interlock sleeve is telescoped with the proximal end of the main body, the interlock sleeve translatable in longitudinal direction between a proximal position and a distal position and biased in proximal direction in a manner to protrude from the main body in the proximal position, wherein in its proximal position the interlock sleeve is arranged to prevent translation of the syringe in proximal direction from its retracted position and wherein the interlock sleeve in its distal position is arranged to allow translation of the syringe in proximal direction.

10. The auto-injector according to claim 9 , characterized in that at least one resilient second clip is arranged on the main body, the second clip being biased so as to block the trigger button from being translated in proximal direction when relaxed, wherein the interlock sleeve in its distal position is arranged to push the clip against its bias so as to decouple it from the trigger button thus allowing translation of the trigger button in proximal direction.

11. The auto-injector according to claim 9 , characterized in that the interlock sleeve in its distal position is arranged to prevent release of the distal ground of the drive spring.

12. The auto-injector according to claim 9 , characterized in that a retraction sleeve is axially movable arranged in the main body, wherein the drive spring is arranged inside the retraction sleeve with its distal end bearing against a distal end face and with its proximal end bearing against a thrust face of a decoupling member, wherein at least one resilient clip is arranged at the proximal end of the retraction sleeve, wherein the main body has a respective recess for accommodating the resilient clip when the retraction sleeve is in its proximal position wherein the interlock sleeve in its distal position is arranged to support the resilient clip from inside so as to prevent it from translating in distal direction.

13. The auto-injector according to claim 9 , characterized in that a tubular syringe carrier is arranged for holding the syringe and supporting it at its proximal end, the syringe and the syringe carrier arranged for joint axial translation, wherein the syringe carrier is telescoped in the interlock sleeve, wherein at least one resilient second latch is arranged in the main body ear the proximal end, wherein in an as delivered state the resilient second latch extends inwards in a manner to prevent the syringe carrier from translating in proximal direction, wherein the resilient second latch is arranged to be disengaged from the syringe carrier upon translation of the interlock sleeve in distal direction.

14. The auto-injector according to claim 12 , characterized in that at least two resilient decoupling arms are arranged at the decoupling member, the decoupling arms having inner ramped surfaces bearing against a first shoulder of the plunger in proximal direction, wherein the resilient decoupling arms are supportable by an inner wall of the retraction sleeve in order to prevent the decoupling arms from being flexed outward and slip past the first shoulder and wherein at least one aperture is arranged in the retraction sleeve allowing the decoupling arms to be flexed outward by the first shoulder thus allowing the first shoulder to slip through the decoupling arms in proximal direction, wherein the plunger is arranged for pushing the syringe and/or the stopper in proximal direction.

15. The auto-injector according to claim 12 , characterized in that the syringe is arranged for joint axial movement with a syringe holder which is slidably arranged in the refraction sleeve, wherein the syringe holder is provided with at least two resilient syringe holder arms arranged distally, the syringe holder arms having a respective inclined surface for bearing against a second shoulder, which is arranged at the plunger proximally from the first shoulder wherein the syringe holder arms are supportable by an inner surface of the main body in order to prevent them from being flexed outward and wherein a widened portion is provided in th

Assignees

• Hourmand Yannick
• Barrow-Williams Timothy Donald
• Ekman Matthew
• Sanofi Aventis Deutschland

Inventors

• Hourmand Yannick
• Barrow-Williams Timothy Donald
• Ekman Matthew

Classifications

• A61M5/484 Primary

  Regulating injection pressure · CPC title

• A61M5/321

  Means for protection against accidental injuries by used needles · CPC title

• A61M5/482

  Varying injection pressure, e.g. by varying speed of injection · CPC title

• A61M2005/206

  With automatic needle insertion · CPC title

• A61M2005/31508

  provided on the piston-rod · CPC title