Hand maneuverable welding gun

A hand maneuverable laser welding gun for joining two or more overlaid metal pieces, comprising:

• an elongated support column extending along a longitudinal axis;
• an optical head axially displaceable along the support column and provided with optics which are configured to focus a laser beam along a path through a protective window of the optical head on a welding zone,
• a first arm mounted to the support column along the path downstream from the protective window and coupled to the optical head to axially move between a home position and a welding position in which the arm presses against one of the metal pieces so as to enclose the welding zone to prevent laser emission from escaping outside the welding zone during welding,
• the first arm being configured with a hollow housing provided with an inner peripheral surface which defines an elongated tunnel traversed by the laser beam which axially propagates from an upstream to a downstream end of the housing, the housing having:
• a recess traversed by a first stream of a pressurized medium which enters the upstream end of the tunnel at a first pressure sufficient to prevent welding debris from reaching the protective window,
• an inlet traversed opening into the the upstream end at a distance from the recess, the inlet being traversed by a second stream of gaseous medium entering the upstream end of the tunnel at a second pressure which is lower than the first pressure and selected to prevent formation of air vortexes in the tunnel, and
• a suction outlet provided in the housing and opening into the downstream end of the tunnel, the suction outlet being under a third pressure creating a pressure gradient between the upstream and downstream ends sufficient for the first and second streams axially copropagate through the tunnel along with the laser beam and are extracted from the tunnel through the suction outlet.