Patent ID: 7854722

Claim:
A needle-containing medical device comprising: a needle assembly which contains a needle and a needle holder to which the needle is attached, a housing having a front portion and a rear portion, a retractable body in the front portion of the housing and able to be retracted from a front position to a rear portion of the housing, a retraction mechanism comprising a biasing means to bias the retractable body to the rear portion of the housing, a holding means to hold the retractable body in the front of the housing against the bias, and a release means comprising a frangible portion that is broken by a plunger, the breaking of the frangible portion by the plunger triggering the biasing means to bias the retractable body to the rear portion of the housing; attachment means comprising a thread on the front of the retractable body and a thread on the needle holder that threadingly engages and disengages with the thread on the front of the retractable body to releasably attach to the needle holder thereby enabling the needle assembly to be removed from the retractable body and another needle assembly to be attached to the retractable body and to retract the needle assembly into the housing upon retraction of the retractable body; and anti-rotation means on the retractable body to prevent the retractable body from rotating relative to the retraction mechanism thereby preventing the frangible portion from breaking when the needle holder threadingly engages and disengages with the thread on the front of the retractable body.