Automatic injection device

Claim 1

An automatic device for injecting two or more different injection liquids which may not be in contact with each other for long periods of time, comprising a combination of a discharge mechanism, a cartridge holder and a cartridge which is slidably accommodated in the holder and which comprises an ampoule, a piston which is movable in the ampoule and seals same, and a hypodermic needle connected to the front of the ampoule by means of a needle mount, and, if desired, covered by a flexible sheath to maintain the needle in a sterile condition, said device being characterized in (a) that said cartridge includes said injection liquids and the ampoule between the piston and the needle mount comprises one or more stoppers which are movable in the ampoule and which, before use of the device, keep the injection liquids present in the ampoule separated from each other in that their circumference adjoins the inner wall of the ampoule in a sealing manner, (b) that said cartridge includes means maintaining most of the peripheral area of said ampoule in radially spaced relationship from said holder, (c) that the needle mount comprises a neck connected to the front of said ampoule in which the injection needle is sealingly connected, (d) that the rear face of the neck of the needle mount or the front face of the stopper nearest to the rear face of the neck of the needle mount comprises a plurality of spacing supports, and (e) that the inner wall of the ampoule is locally deformed between the needle mount and the stopper or foremost stopper over a length which is slightly larger than the length of the stopper or the collected stoppers in such a manner that upon actuation of the device a bypass is formed, allowing the injection liquid or liquids behind the stopper or stoppers to reach the needle past the stopper or stoppers.