Probe-holder armature with a sensor probe

Probe-holder armature comprising a sensor probe that is removably arranged in the forward portion of an immersion tube which is axially movable in a housing between a retracted rest position and a deployed working position, wherein the sensor probe in its installed condition provides a medium-tight closure of the immersion tube, wherein the immersion tube has a removable insert which can be held in a fixed position by means of a closure member and by means of which the sensor probe in its installed position is pushed forward against a forward stop of the immersion tube, wherein a safety device is provided which prevents an axial movement of the immersion tube out of its rest position if one or more of the three components sensor probe, insert and closure member are missing, characterized in that the safety device has a safety slide which surrounds the rear end of the insert like a sleeve and which is movable between a further forward stop and a rearward stop inside the immersion tube from a first locking position through a releasing position to a second locking position, wherein the safety slide cooperates with at least one locking member that is arranged with radial mobility in the immersion tube, wherein in the locking position of the safety slide, the locking member sits with its inward-facing side against the outside surface of the safety slide while the outward-facing side of the locking member engages a locking recess in the housing, and wherein in the releasing position of the safety slide the locking member engages at its inward-facing side a circumferential groove in the safety slide, while the outward-facing side of the locking member is freed from the locking recess of the housing.