| abstract |
A cartridge based syringe system utilizes a cartridge piston having an interlocking needle receiving cup and retraction cage structure graspable by a conventional plunger hook, and a break-away needle assembly, in order to provide simple and reliable retraction of a needle cannula into a disposable medicant cartridge. Needle retraction is accomplished by simply reversing the movement of the plunger at the end of an injection stroke. A conventional type of dental syringe can be readily converted into a safety syringe providing the aforementioned needle retraction simply by replacing the disposable parts, i.e., the needle assembly and the medicant cartridge. |