An improved syringe apparatus for use with interchangeable, disposable medicinal ampoules is provided with an advantageous mechanism for facilitated, one-handed operation in the ejection of a spent ampoule. The improved construction also includes a needle ejector projection for one-handed ejection of...http://www.google.co.uk/patents/US5451214?utm_source=gb-gplus-sharePatent US5451214 - Syringe apparatus
