A syringe apparatus includes a housing having upper and lower end portions and a hollow interior. A rotary cam position inside the hollow interior has a projecting portion for operating a cartridge when the apparatus is used. The housing has a rotary bearing for supporting the cam. A syringe cartridge...http://www.google.com/patents/US5865804?utm_source=gb-gplus-sharePatent US5865804 - Rotary cam syringe
