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EP-3744373-B1 - DETENT MECHANISM

EP3744373B1EP 3744373 B1EP3744373 B1EP 3744373B1EP-3744373-B1

Inventors

  • BRERETON, SIMON FRANCIS
  • KEMP, THOMAS MARK
  • BURNELL, ROSIE
  • EKMAN, MATTHEW

Dates

Publication Date
20260513
Application Date
20120216

Claims (9)

  1. Auto-injector comprising: - a syringe (3) with a hollow injection needle, wherein the auto-injector comprises a stopper (6) located in the syringe, the stopper being arranged for sealing the syringe distally; and - a noise release mechanism for audibly indicating the end of injection, wherein the noise release mechanism comprises a releasable noise component (28), wherein the noise component is capable of, upon release, generating an audible feedback, wherein the noise component is arranged to be released when a plunger reaches a position relative to a syringe in which the stopper is located in proximity of a proximal end of the syringe, and wherein the released noise component impacts on a housing component of the auto-injector - wherein, when the noise component (28) is released by the plunger (9), the noise component (28) moves in the distal direction (D) and impacts the housing component.
  2. Auto-injector according to claim 1, wherein the housing component is a case (12) of the auto-injector.
  3. Auto-injector comprising according to claim 1 or 2, wherein the housing component is a sleeve trigger of the auto-injector.
  4. Auto-injector according to claim 1, wherein the housing component is a trigger button (13) of the auto-injector.
  5. Auto-injector according to any one of the preceding claims, wherein the syringe (3) is held in a tubular carrier (7) and supported at its proximal end therein.
  6. Auto-injector according to claim 5, wherein a drive spring (8) in the shape of a compression spring is arranged in a distal part of the carrier (7).
  7. Auto-injector according to claim 6, wherein the plunger (9) serves for forwarding the force of the drive spring (8) to the stopper (6).
  8. Auto-injector according to any one of claims 5 to 7, wherein a noise spring (29) acts between the carrier (7) and the noise component (28).
  9. Auto-injector according to any one of the preceding claims and claim 2 or any claim depending on claim 2, wherein the auto-injector comprises a chassis (2), wherein the chassis protrudes from the case (12) at a proximal end and is arranged to be placed against an injection site.

Description

Technical Field The invention relates to an auto-injector. Background of the Invention Detent mechanisms are applied to control motion of components relative to each other in a manner keeping them in a defined relative position until a predetermined force is overcome suddenly allowing one of the components to move relative to the other, wherein the subsequent motion can be achieved by application of a significantly reduced force. The motion may end at another relative position defined by the detent mechanism in such a manner that a predetermined force has to be overcome to move the component back into its initial position. Such detent mechanisms may be applied to define the position of a drawer in furniture or in a car or to define positions of components within medical equipment. Autoinjectors are available in the prior art. For example, WO 2010/035059 A1 relates to an automatic injection device with audible indicator of completed injection. WO 2010/035057 A1 relates to an autoinjector with audible indication of completed delivery. WO 2009/141650 A2 relates to an injection device. Furthermore, WO 2006/079481 A1 relates to an injection device with an end of dose feedback mechanism. Summary of the Invention It is an object of the present invention to provide a novel auto-injector. The object is achieved by an auto-injector according to claim 1. Preferred embodiments of the invention are given in the dependent claims. In the context of this specification the term proximal refers to the direction pointing towards the patient during an injection while the term distal refers to the opposite direction pointing away from the patient. The term inwards refers to a radial direction pointing towards a longitudinal axis of the auto-injector whereas the term outwards refers to the opposite direction radially pointing away from the longitudinal axis. According to an embodiment useful for understanding the invention a detent mechanism for controlling translation between two components in a longitudinal direction, i.e. a proximal or distal direction comprises at least one clip on one of the components arranged to be in a ramped engagement with a recess in the other one of the components in an initial state in such a manner that translation between the components is constrained and that application of a translative force between the components in one longitudinal direction when the clip is engaged with the recess deflects the clip out of the recess when a predetermined value of the translative force, at least depending on the resilience of the clip is overcome so as to allow translation between the components. As the clip is sufficiently deflected it is disengaged from the recess and allowed to travel along the other component on continued relative translation of the components, which requires significantly less force than the force for deflecting the clip. When the force for overcoming the detent is applied by a user they will not be able to suddenly reduce the force after deflection so the component will be swiftly moved. At least one clip may be arranged as a resilient beam on one of the components biased towards the other component, the clip extending from the one component in the proximal direction, the clip arranged to abut the other component in the proximal direction preventing translation, wherein a ramp feature on a third component is slidable in the longitudinal direction in a manner to engage the clip in a ramped engagement deflecting the clip against its bias for unlocking the clip from the other component. The clip for preventing relative motion and the clip for constraining relative motion may be different clips. In one embodiment useful for understanding the invention the clip for preventing relative motion and the clip for constraining relative motion are integrated with each other. In this case the clip may be arranged to abut the other component in the proximal direction in the initial state preventing translation, wherein the ramp feature on the third component on translation is arranged to deflect the clip a first level out of the abutment so as to allow but constrain relative translation by the clip now being in a ramped engagement with the recess when deflected in the first level. Application of the translative force between the components in one longitudinal direction when the clip is in the first level deflects the clip out of the recess a second level when the predetermined value of the translative force is overcome so as to allow translation between the components. As the clip is sufficiently deflected it is disengaged from the recess and allowed to travel along the other component on continued relative translation of the components, which requires significantly less force than the force for deflecting the clip. The clip, when translated out of its initial position in the initial state, may be arranged to push against the other component in a transversal direction generating a friction force oppos