An improved safety hypodermic syringe includes a reciprocal tubular needle sheath disposed on the exterior of the syringe body, a latch mechanism engaging the syringe body and the sheath to latch the sheath in a needle-covering position after delivering contents from the syringe body, and a spring engaging...http://www.google.com.au/patents/US20100042053?utm_source=gb-gplus-sharePatent US20100042053 - SAFETY SYRINGE
