Patent ID: 7637888

Claim:
A syringe comprising: a casing, a piston that is slidably guided in the casing, a needle adapted to be withdrawn into the casing, and a coupling for connecting together the piston and the needle, the coupling being adapted to assume three states in the following order: a releasable coupling state in which the needle is adapted to be moved towards a front end of the casing together with the piston, an uncoupled state in which the piston is adapted to be moved back in the casing separately from the needle, and a permanent coupling state in which the needle is adapted to be withdrawn into the casing by the piston wherein the coupling comprises: a locking mechanism establishing a connection with tensile strength between the piston and the needle, and at least one elastically biased element which, in a biased state a force is applied thereto, prevents the locking mechanism from being locked when the coupling is in the releasable coupling state, whereas, in a non-biased state, it permits an engagement of the locking mechanism when the coupling is in the permanent coupling state.