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EP-3595746-B1 - LOW FORCE TRIGGER

EP3595746B1EP 3595746 B1EP3595746 B1EP 3595746B1EP-3595746-B1

Inventors

  • ZHANG, KUIWEI

Dates

Publication Date
20260513
Application Date
20180315

Claims (9)

  1. An injection device for receiving a syringe therein and for delivering a dose of medicament from the syringe, the injection device comprising: a driver mechanism (204) retainable in a primed state and releasable from the primed state for driving one or more features of the injection device forwards, a trigger mechanism (202) comprising a ramped surface (230) engaged with the driver mechanism to retain the driver mechanism in the primed state, wherein the trigger mechanism comprises a rotatable collar (208), which comprises the ramped surface (230), and wherein actuation of the trigger mechanism comprises rotation of the collar (208), and wherein the trigger mechanism (202) is configured to translate a linear actuation force into rotation of the collar, the trigger mechanism (202) being configured on actuation thereof to withdraw the ramped surface (230) from engagement with the driver mechanism for release thereof, wherein the driver mechanism comprises a release lug (236) configured to engage the ramped surface, and wherein the driver mechanism is configured to exert a force biasing the release lug onto the ramped surface for assisting withdrawal of the ramped surface.
  2. An injection device according to claim 1, wherein the trigger mechanism (202) comprises a trigger lug (212) configured to engage with a ramped section (226) of a trigger track on the collar for rotating the collar.
  3. An injection device according to claim 2, wherein the trigger track (220) further comprises an axial section (224), and wherein the trigger lug (212) is configured to engage with the axial section, such that rotation of the collar is prevented when the driver mechanism is retained in the primed state.
  4. An injection device according to any preceding claim, further comprising a trigger (206) configured to be operated by a user and to actuate the trigger mechanism (202) when operated.
  5. An injection device according to claim 4, wherein the trigger (206) comprises an actuator configured to move rearwards under a force resulting from pressing a forward end of the injection device against an injection site.
  6. An injection device according to claim 4 or 5 wherein the trigger (206) comprises a trigger button (209) configured to be operated by depression thereof by the user.
  7. An injection device according to claim 5 or 6, when dependent directly or indirectly on claim 4, wherein the trigger lug (212) is directly coupled to the trigger button (209) or the actuator, and wherein operation of the trigger button (209) or the actuator causes the trigger lug (212) to engage with the ramped section (226) of the trigger track (220).
  8. An injection device according to any preceding claim wherein the driver mechanism comprises a compression spring.
  9. An injection device according to any preceding claim, wherein the driver mechanism (204) is configured to drive forwards one or more of: the syringe for insertion of a needle of the syringe into an injection site; and a plunger of the syringe for delivery of the dose of medicament.

Description

Technical field This invention relates to injection devices for delivering a dose of medicament from a syringe. In particular, but not exclusively, the invention relates to an autoinjector type device which facilitates powered or power assisted needle insertion and injection. Background Injection devices are used for the convenient administration of medicaments. For example, injection devices (which may typically be in the form of a pen injector) may be used for providing a single metered dose of a medicament, for example such as Epinephrine in an emergency or for providing regular metered doses of a medicament such as Insulin. Such devices may be either single use "disposable" devices in which the device is typically provided with a syringe already installed, and which is not user-replaceable, or "reusable" devices which allow the user to replace the syringe when the medicament has been used. It is noted that whilst the term "syringe" is used herein for clarity and consistency, this term is not intended to be limiting. In some arrangements the syringe may for example be a cartridge (which, for example, may be arranged to receive a disposable needle) or other medicament container. In some arrangements the syringe/cartridge/medicament container may be formed integrally with the (or part of the) injection device. Injection devices may be provided in the form of an "autoinjector" device, in which, in addition to automating the delivery of the medicament, the device is also arranged to automate the insertion of a needle into the skin prior to the delivery of the medicament. Injection devices generally comprise a delivery arrangement which is arranged to automatically deliver a dose from the syringe, and optionally (in the case of an autoinjector) to first displace the syringe within the housing to cause needle penetration. The delivery arrangement generally acts via a plunger which includes or engages a piston (also referred to as a "bung") which is slidably provided within the syringe. In the case of an autoinjector the initial static friction or "stiction" between the bung and syringe resists forward movement of the piston relative to the syringe such that initially the delivery arrangement moves the syringe and piston forward into the needle insertion position. Here, further movement of the syringe is blocked and the delivery arrangement will continue to move forward, overcoming the stiction, and moving the piston and the bung through the syringe. A common form of delivery arrangement includes a driver mechanism which biases the plunger forwardly and a trigger mechanism which holds the plunger (directly or indirectly) against the force of the driver mechanism until the trigger is released. For example the driver mechanism may comprise a drive spring (for example a compression spring) which is held in an energised (or primed position) prior to release by the trigger. An injection device of the autoinjector type is described in WO2016/189286. GB2538566A relates to an injection device with a cam to control the speed of plunger movement. WO2008/112472A2 relates to a delay mechanism for automatic injection devices. WO2014/159018A1 relates to a trigger assembly for an automatic injection device. WO2015/011488A1 relates to pen injector devices. WO2016/174245A1 relates to an injection device with a safe trigger function. At least some embodiments of the invention seek to provide an improved injection device which may help to address some of these problems. Summary According to an aspect of the invention there is provided an injection device for receiving a syringe therein and for delivering a dose of medicament from the syringe, the injection device comprising: a driver mechanism retainable in a primed state and releasable from the primed state for driving one or more features of the injection device forwards, a trigger mechanism comprising a ramped surface engaged with the driver mechanism to retain the driver mechanism in the primed state, the trigger mechanism being configured on actuation thereof to withdraw the ramped surface from engagement with the driver mechanism for release thereof. The trigger mechanism comprises a rotatable collar, which comprises the ramped surface, and wherein actuation of the trigger mechanism comprises rotation of the collar. The trigger mechanism is configured to translate a linear actuation force into rotation of the collar. Optionally, the trigger mechanism comprises a trigger lug configured to engage with a ramped section of a trigger track on the collar for rotating the collar. Optionally, the trigger track further comprises an axial section, and wherein the trigger lug is configured to engage with the axial section, such that rotation of the collar is prevented when the driver mechanism is retained in the primed state. Optionally, the injection device according to any preceding claim, further comprising a trigger configured to be operated by a user and to actuate the trigger me