A plug connector may comprise an expanding ring, a plug contact element, a first connector housing stop, and a locking ring. The plug contact element may comprise a coil spring with a first end and a second end, where the second end of the coil spring may be coupled to the expanding ring. The first connector housing stop may be configured to absorb a pressure in a first rotational direction and block the first end of the coil spring from rotating in the first rotation direction. The locking ring may be configured to absorb a pressure in a second rotational direction opposite the first rotational direction. The locking ring may be configured to block the expanding ring when the plug connector is in an open state and unblock the expanding ring when the plug connector is in a closed state.