TAPPING UNIT WITH PROTECTION MEANS

摘要

A tapping unit (1) includes a protection device (12) for permitting an axial retraction movement of a master screw (4) towards the interior of a casing (2) from a reference position into a first proximal backward position with a first defined penetration stroke during which a first elastic return device (13) constantly returns the master screw (4) to its reference position. The protection device (12) furthermore permits an additional axial retraction movement of the master screw (4) towards the interior of the casing (2) from the proximal backward position into a second proximal backward position with a defined penetration stroke during which the master screw (4) is no longer returned towards the exterior of the casing (2).