Auto-injector

Patent metadata

Field	Value
Publication number	US-9707356-B2
Application number	US-201113807268-A
Country	US
Kind code	B2
Filing date	Jun 20, 2011
Priority date	Jun 28, 2010
Publication date	Jul 18, 2017
Grant date	Jul 18, 2017

Abstract

An auto-injector comprising a housing containing a syringe with a hollow needle and a stopper for sealing the syringe and displacing the medicament. A spring capable of, upon activation: pushing the needle from a covered position inside the housing 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 locks the spring in a pressurized state prior to operation and, upon manual operation, releasing the spring for injection. An interlock sleeve telescoped in the housing and translatable in longitudinal direction, wherein in a proximal position the interlock sleeve is arranged to be coupled to the syringe in the syringe's retracted position and wherein the interlock sleeve in its distal position is arranged to allow decoupling of the syringe.

First claim

The invention claimed is:

1. An auto-injector for administering a dose of a liquid medicament, comprising:
an elongate housing;
a syringe in the elongate housing, the syringe comprising a hollow needle and a stopper for sealing the syringe and displacing the medicament, the housing 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 housing;
a spring capable of, upon activation:
pushing the syringe from a retracted position inside the housing 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 retracted 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, the drive spring having a proximal end, a distal end, and a ground, and the drive spring being arranged to have its ground in the housing at the distal end of the drive spring for advancing the needle and for injecting the dose of medicament via a plunger and arranged to have its ground in the housing switched to the proximal end of the drive spring for retracting the syringe;
an interlock sleeve that is telescoped in the proximal end of the housing, the interlock sleeve translatable in a longitudinal direction between a proximal position and a distal position and biased in a proximal direction in a manner to protrude from the housing in the proximal position, wherein in its proximal position the interlock sleeve is arranged to be coupled to the syringe in the syringe's retracted position, and wherein the interlock sleeve in its distal position is arranged to be decoupled from the syringe; and
a syringe carrier holding the syringe and supporting a proximal end of the syringe, the syringe carrier being configured to be telescoped in the interlock sleeve, and the syringe and the syringe carrier being arranged for joint axial translation.

2. The auto-injector according to claim 1 , wherein the interlock sleeve in its distal position is arranged to inhibit release of the ground at the distal end of the drive spring.

3. The auto-injector according to claim 1 , further comprising a retraction sleeve axially movably arranged in the housing,
wherein the drive spring is arranged inside the retraction sleeve with the distal end of the drive spring bearing against a distal end face and with the proximal end of the drive spring bearing against a thrust face of a decoupling member,
wherein a resilient wedge is arranged at the proximal end of the retraction sleeve,
wherein the housing has a recess for accommodating the resilient wedge when the retraction sleeve is in its proximal position, and
wherein the interlock sleeve in its distal position is arranged to support the resilient wedge from inside to inhibit the resilient wedge from translating in a distal direction.

4. The auto-injector according to claim 3 , further comprising a latch for axially fixing the retraction sleeve in a maximum proximal position,
wherein the decoupling member is movable in the proximal direction nearly into a maximum proximal position to decouple the latch, thus allowing the retraction sleeve to move in the distal direction to retract the needle.

5. The auto-injector according to claim 3 , further comprising:
at least two resilient decoupling arms arranged at the decoupling member, the decoupling arms having inner ramped surfaces bearing against a first shoulder of the plunger in the proximal direction, wherein the resilient decoupling arms are supportable by an inner wall of the retraction sleeve to inhibit the decoupling arms from being flexed outward and slipping past the first shoulder; and
at least one aperture arranged in the retraction sleeve to receive the decoupling arms when the first shoulder causes the decoupling arms to move outward, thus allowing the first shoulder to slip through the decoupling arms in the proximal direction, wherein the plunger is arranged for pushing the syringe and/or the stopper in the proximal direction.

6. The auto-injector according to claim 5 , wherein the aperture extends at least almost to the position of the decoupling arms in an as delivered state,
wherein the aperture is arranged to be angularly misaligned with respect to the decoupling arms when the retraction sleeve is in its proximal position, and
wherein the aperture is arranged to rotate so as to align with the decoupling arms upon translation of the retraction sleeve out of the proximal position in the distal direction.

7. The auto-injector according to claim 6 , further comprising:
a cam track arranged in the housing; and
a cam follower arranged in the retraction sleeve,
wherein the cam track is essentially parallel to a longitudinal axis of the auto-injector with a short angled section at its proximal end.

8. The auto-injector according to claim 6 , further comprising:
a cam track arranged in the retraction sleeve; and
a cam follower arranged in the housing,
wherein the cam track is essentially parallel to a longitudinal axis of the auto-injector with a short angled section at its proximal end.

9. The auto-injector according to claim 3 , wherein the syringe is arranged for joint axial movement with a syringe holder slidably arranged in the retraction 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 of the plunger arranged proximally from a first shoulder of the plunger,
wherein the syringe holder arms are supportable by an inner surface of the housing to inhibit the syringe holder arms from being flexed outward, and
wherein a widened portion is provided in the housing for allowing the syringe holder arms to flex outwards when the syringe holder has nearly reached a maximum proximal position thus allowing the second shoulder to slip through the syringe holder arms and to switch load of the drive spring from the syringe to the stopper.

10. The auto-injector according to claim 3 , further comprising a stud arranged at a distal end of the plunger,
wherein the retraction sleeve has two or more resilient arms positioned distally from the distal end face for holding the stud, the stud and/or the resilient arms having ramp features such that the resilient arms are pushed apart by the stud when the plunger is moved in the proximal direction,
wherein the trigger comprises a trigger button arranged at a distal end of the auto-injector, the trigger button axially moveable and having at least two rigid retainers to inhibit the resilient arms from being flexed outward when the trigger button is in a distal position, and
wherein, upon pushing the trigger button in the proximal direction the retainers are moved in the proximal direction in a manner to allow the resilient arms to be flexed out by the stud biased by the drive spring in the proximal direction thus allowing the stud to slip past the resilient arms in the proximal direction.

11. The auto-injector according to claim 1 , further comprising a resilient latch arranged in the housing near the proximal end,
wherein in an as delivered state the resilient latch extends inwards to inhibit the syringe carrier from translating in the proximal direction, and
wherein the resilient latch is arranged to be disengaged from the syringe carrier upon translation of the interloc

Assignees

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

Inventors

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

Classifications

• A61M5/326

  Fully automatic sleeve extension, i.e. in which triggering of the sleeve does not require a deliberate action by the user · CPC title

• A61M5/31511

  Piston or piston-rod constructions, e.g. connection of piston with piston-rod (A61M5/5066 takes precedence) · CPC title

• A61M2005/208

  Release is possible only when device is pushed against the skin, e.g. using a trigger which is blocked or inactive when the device is not pushed against the skin · CPC title

• A61M5/46

  having means for controlling depth of insertion · CPC title

• A61M5/2033 Primary

  Spring-loaded one-shot injectors with or without automatic needle insertion (multishot dosing syringes A61M5/31525, needle insertion only A61M5/3287) · CPC title