Disclosed is an injection device including a body for receiving a syringe, a firing mechanism including a reaction component, a plunger configured to be axially displaced in a forward direction relative to the reaction component, and a drive spring located between the reaction component and the plunger for driving the plunger forwards upon activation of the injection device, wherein the reaction component provides a reaction surface for the drive spring. The device further includes a locking mechanism for locking the reaction component in a first axial position within the body, the locking mechanism being configured to release the reaction component upon a predefined forward movement of the plunger thereby allowing the reaction component to be driven in a rearward axial direction by the drive spring until it impacts against the body or a component secured to the body to thereby emit an audible indication of an end of dose.

An injection device for delivering a dose of medicament from a syringe (5), the injection device comprising a housing (10), a plunger (210) moveably mounted within the housing (10), an actuation mechanism (200), a trigger mechanism (40), and a plunger velocity regulator. The actuation (mechanism (100) is arranged to provide a forward biasing force to urge the plunger (210) forward in use to express a dose of medicament, and the trigger mechanism (40) is arranged to releasably hold the plunger (210) against the force of the actuation mechanism (200). The plunger velocity regulator comprises a cam surface (262) associated with the housing, and a cam member (252) associated with the plunger (210) and arranged to engage the cam surface (262) during actuation movement of the plunger (210) such that axial movement of the plunger (210) relative to the housing (10) causes relative rotational movement of the cam member (252) which limits the forward velocity of the plunger movement. The plunger (210) is axially connected to the cam member (252) by a releasable coupling (300), and the plunger velocity regulator further comprises a coupling member (350) which blocks release of the releasable coupling (300) when the plunger (210) is in a rearward position and wherein forward movement of the plunger (210) moves the releasable coupling (300) out of engagement with the coupling member (350) such that the plunger (210) may disengage the cam member (252) after an initial movement of the plunger (210).

An autoinjector including a plunger for engaging with the bung, a collar located around the plunger, an insertion spring biasing the collar relative to the rear of the device, and a delivery spring biasing the plunger relative to the collar. The device further includes a stop feature defining the limit of axial movement of the syringe body through the housing, and a collar release mechanism for releasing the collar from the rear of the device to commence insertion and a plunger release mechanism for releasing the plunger from the collar while substantially preventing rearward axial movement of the collar, following insertion, to commence delivery of the medicament. Following release of the plunger from the collar, the plunger is configured to move axially and rotationally relative to the collar, the direction of rotation being changed one or more times with axial movement of the plunger.

A drug delivery device includes a housing defining a shell, a drug delivery assembly at least partially disposed within the housing, a cap defining an opening and being adapted to at least partially cover an end of the housing, at least one electronic component, a power source which powers the at least one electronic component, and a switch assembly. The drug delivery assembly comprises a guard which engages an inner surface of the housing and is movable between a first position, a second position, and a third position relative to the housing and is adapted to restrict external contact with a cannula. The switch assembly causes the power source to provide power to the at least one electronic component when the cap is removed from the housing, restrict the power source from providing power when the cap is coupled to the housing and the guard is in the first position, and cause the power source to provide power when the cap is coupled to the housing and the guard is in the third position.

Disclosed is a pen needle including: a needle; a needle hub which comprises a coupling structure, which can be screw-coupled to a body, holds the needle and has protrusions formed on a supporting surface; a spring which has one side supported on the supporting surface and provides resilience; a plunger which has a plurality of resilient blades, which can be folded or unfolded, and has a hollow through which the needle passes; a small cap which is supported on the other side of the spring and receives the plurality of blades such that the plurality of blades can be received therein or be dislodged; and a medium cap which is coupled to the small cap, accommodates the small cap such that the small cap can move, and has serrations corresponding to the protrusions.

Disclosed is an injection device for delivering a medicament from a syringe contained within a housing, the device being configured to move the syringe through the housing to cause insertion of a needle of the syringe into a user's skin and move a syringe bung through a syringe body, delivering medicament through the needle. The device includes: a plunger engaging the bung; a sleeve around the plunger; an insertion spring biasing the sleeve to the housing; and a delivery spring biasing the plunger to the sleeve. A release mechanism releases the sleeve from the housing to commence insertion and release the plunger from the sleeve, following insertion, delivering medicament. A velocity regulator regulates the plunger upon release and disengages during delivery, and includes a screw thread associated with the sleeve or plunger and one or more thread engaging members formed on the other of the sleeve and the plunger.

A system for storing and delivering a predetermined amount of fluid includes a syringe including a barrel, a flange disposed at the proximal end of the barrel, and a plunger assembly configured to be received in the lumen of the barrel. The plunger assembly includes a piston and a plunger rod. The plunger rod is removably couplable to the piston at the distal end of the plunger rod and includes a thumb press flange at the proximal end of the plunger rod. The system further includes a stop feature that is removably couplable to the syringe or the plunger assembly. The stop feature is configured to arrest distal advancement of the plunger assembly relative to the syringe when the plunger assembly reaches a predetermined position relative to the syringe. The stop thus ensures that a predetermined amount of fluid remains in the barrel.

Disclosed is an auto-injector for administering a medicament, comprising: a housing; a cartridge receiver configured to receive a cartridge comprising a first stopper; a drive module coupled to move a plunger rod configured to move the first stopper; a resistance sensor configured to provide a resistance signal indicative of resistance against movement of the plunger rod; and a processing unit coupled to the drive module and to the resistance sensor. The processing unit being configured to: control the drive module to move the plunger rod towards the extended plunger rod position; determine present plunger rod position; receive the resistance signal; determine a cartridge parameter based on the resistance signal and the present plunger rod position; and control the drive module to adjust the movement of the plunger rod based on the cartridge parameter.

Disclosed is an injection device for receiving a syringe therein and for delivering a dose of medicament from the syringe, the injection device including: an insertion driver configured to drive the syringe forwards within the injection device for inserting a needle of the syringe into an injection site; an interlock mechanism configured to retain the insertion driver in a primed state and, when actuated, to allow the insertion driver to drive the syringe forwards; and an interlock actuator moveable between a stowed position and an operable position and configured on movement from the stowed position to the operable position to couple to an actuation system such that movement from the operable position back towards the stowed position actuates the interlock mechanism.

A feedback mechanism for an injection device that is configured to deliver a medicament to a user is described. The feedback mechanism comprises a piston and a fluid chamber, and the piston is adapted to move into the fluid chamber during use of the injection device. The feedback mechanism also has a damper that is arranged to damp movement of the piston, and an indicator that is arranged to provide feedback to the user after the piston has moved a pre-determined distance into the fluid chamber.