Disclosed is a hypodermic injection device wherein the needle can be retracted into the reservoir chamber, after use, for disposal. The device includes a plunger having a needle-retention chamber in the end of the plunger closest to the needle structure. The end portion of the needle can be resilient,...http://www.google.co.uk/patents/US5061249?utm_source=gb-gplus-sharePatent US5061249 - Hypodermic injection device
