A locking syringe selectively operable in either of a freely reciprocating or a restricted, threaded mode. A trigger attached to the plunger includes internal threads on the interior of the barrel of the syringe and external threads located on the plunger on a spine slidable in a longitudinal slot in...http://www.google.ca/patents/US5209732?utm_source=gb-gplus-sharePatent US5209732 - Locking syringe with thread-release lock
