Patent ID: 8734402

Claim:
An automatic injection device, comprising: a syringe having a needle, a barrel and a plunger; and driving means for driving the plunger into the barrel; wherein the injection device is configured to perform an automatic actuation cycle in use comprising the stages of advancing the needle of the syringe for insertion, driving the plunger into the barrel for dispensing a liquid contained in the barrel, and retracting the needle; wherein the device is configured such that during operation of the device, a driving force is transmitted from the driving means to the plunger during the dispensing stage, and such that a driving force is not transmitted to the plunger during the refraction stage to allow retraction of the needle; wherein the automatic injection device comprises a drive coupling arrangement between said driving means and said syringe; wherein said drive coupling arrangement comprises a drive coupling part selectively transmitting or not transmitting force from the driving means to the plunger depending upon the rotational position of the coupling part; wherein the device is configured such that, depending upon a configuration of the drive coupling arrangement, the syringe is driven forward during the needle advancement stage and the plunger is driven into the barrel during the dispensing stage for dispensing a liquid contained in the barrel, and wherein a transition between said needle advancement and dispensing stages is controlled by the rotation of a part of said drive coupling arrangement.