Electrical connector

Claim 1

A PLUG FOR CONNECTING AN ELECTRIC WIRE TO AN ELECTRIC CIRCUIT HAVING SPACED PAIRS OF SPRING CONTACTS, COMPRISING A GENERALLY CYLINDRICAL BODY, A PIN SUPPORTED IN SAID BODY AXIALLY THEREOF, SAID PIN HAVING A NON-CONDUCTIVE TIP AND A CYLINDRICAL SHELL SUPPORTED BY SAID BODY IN AXIAL ALIGNMENT THEREWITH, SAID PIN EXTENDING AXIALLY OUT OF ONE END OF SAID BODY, SAID SHELL BEING AXIALLY MOVABLE IN SAID BODY AND HAVING A PORTION EXTENDING OUTWARDLY OF SAID BODY, AND HAVING A PORTION EXTENDING OUTWARDLY OF SAID BODY, SAID PORTION SURROUNDING AT LEAST PART OF SAID PIN IN ALL POSITIONS OF SAID SHELL, SPRING MEANS BIASING SAID SHELL OUTWARDLY OF SAID BODY SO THAT SAID CONDUCTIVE PORTION OF THE PIN IS WHOLLY CONCEALED AND SHIELDED BY SAID SHELL WHEN THE SHELL IS FULLY EXTENDED FROM SAID BODY, SAID CONDUCTIVE PORTION OF THE PIN BEING EXPOSED WHEN THE SHELL IS FULLY RETRACTED INTO SAID BODY, A HEAD AT THE OTHER END OF SAID BODY, AN INSULATION FITTING IN SAID BODY, SAID FITTING HAVING A TUBULAR PORTION CARRYING SAID SPRING MEANS AND DETACHABLY ENGAGED WITH SAID CONDUCTIVE PORTION OF THE PIN, SAID FITTING HAVING A PASSAGE THERETHROUGH FOR RECEIVING SAID ELECTRIC WIRE, SAID CONDUCTIVE PORTION OF THE PIN HAVING AN END EXPOSED IN SAID TUBULAR PORTION OF THE FITTING FOR CONNECTION OF SAID WIRE THERETO, SAID FITTING HAVING A FLANGE AT ONE END, AND THREADED MEANS DETACHABLY HOLDIN SAID FLANGE AND HEAD TOGETHER, WHEREBY SAID FITTING AND PIN ARE HELD RIGIDLY IN AXIAL ALIGNMENT WITHIN SAID BODY.