Safety needle with spring-loaded shield

Abstract

A device for protecting practitioners from inadvertent punctures with contaminated needles. The device comprises a safety shield (40), needle (51), handle (34), and a helical spring (35). Needle (40) and spring (35) are molded into handle (34) with needle tip (52) projecting forward. The opposite end of spring (35) is attached to shield (40) such that spring (35) is compressed when shield (40) is in a retracted position. Handle (34) comprises a receiving hub (28) with lock tabs (30) for securing the invention to a syringe, and a latching tube (37) with notches (38a and 38b) formed on the interior. The safety mechanism is activated by squeezing finger grips (36a) and (36b). This action increases the distance between notches (38a) and (38b), thereby releasing safety shield (40). Spring (35) is designed so that its natural length is slightly shorter than is necessary for center hole (48) to reach needle tip (52). However, the momentum of shield (40) carries it well past the natural length of spring (35) and causes shield (40) to extend past tip (52). The interior of shield (40) is designed with a cavity (44) which catches tip (52) as shield (40) returns toward handle (34). Because shield (40) can extend a considerable distance beyond needle (51) when released, the ensuing impact of shield (40) against tip (52) causes the blunting of tip (52) so that needle (51) can not be reused.