RETRACTABLE NEEDLE AND SYRINGE COMBINATION

摘要

A combination hypodermic syringe and needle device in which the needle is retracted inside the syringe after completion of the injection. The device requires only one hand for operation wherein increasing the pressure on the plunger initiates an automatic retraction of the needle into the syringe. In operation, a collet is expanded and a spring biased needle retractor is engaged in response to the forward movement of a plunger. The forward end of the barrel carries a wedge which forces the collet to expand upon forward movement of the collet. A vent located in the plunger allows air to escape from the interior of the plunger as the needle assembly is retracted.