ROTARY LOCK FOR NEEDLE SHEATHS

摘要

A syringe having a rotary lock (22) for a needle sheath. The device has a hollow syringe body having a longitudinal axis, a hollow needle (19) communicating with the hollow syringe body, a sheath (14) reciprocal along said axis to cover and uncover needle, and a latch (16) reciprocable on the sheath to latch the sheath in its extended position over the needle or to unlatch the sheath for retracting the sheath to expose the needle. A lock (22) for the latch comprises a ramp (28) in a plane transverse to the body axis and terminating in a recess and connected to one of said latch and sheath and disposed adjacent to the ramp when the latch is in its position latching the sheath in its extended position covering the needle, whereby relative rotation of the latch and the sheath causes the lug to climb the ramp and drop into the recess and thereby permanently lock the latch against reciprocation and in a position that holds the sheath in a position covering the needle.