Abstract: A mechanical latching device is provided for threaded connections, such as a barrel and hub member of a medical syringe. The latching device includes an abutment and a receptacle for receipt of the abutment whereby relative movements between reciprocal members in one direction is initially terminated and subsequent movements in another direction are resisted. Movement termination in one direction and resistance in another direction may be overcome in one, or both, of the members forming the threaded connection are radially distortable to permit the members to overcome movements interference by the abutment/receptacle relationship.

Abstract: A mechanical latching device is provided for threaded connections, such as those found in a medical syringe. The connections each have a thread profile with crest and root elements. At least one flexible finger or projection extends outwardly from within one of the root portions and an outwardly extending ridge is provided on the second threaded member extending from the ridge. Interference with normal threading movements between connection elements is abated, while resistance is provided to unthreading manipulations of the connections.