US Patent 10322250 Safety needle assembly

A safety needle assembly, including a hub; a needle fixed to the hub, the needle having a distal end and a proximal end; first and second shields, each having a tubular body at least partially encircling a portion of the needle, wherein in an initial state, the first shield extends from the hub; a biasing element disposed to urge the second shield distally toward the distal end of the needle; and a releasable retaining arrangement for releasably retaining the second shield in a first state. Upon a predetermined extent of proximal movement of the first shield relative to the hub, the second shield is released, thereby allowing the biasing element to urge the second shield to a second state in which the distal end of the needle is covered.