Abstract: The fume extraction system (10) includes a fume hood (12) located at the end of an articulated exhaust duct robotic arm (14) Three pairs of photoelectric sensors (34, 36, 38, 40, 42 and 44) are provided on the fume hood (12) to sense the presence of an electric welding arc (64) The system (10) includes a control unit (50) that generates command signals for the arm (14) based on signals received from the sensors so as to automatically position the hood (12) over the arc (64) and maintain a predetermined height distance between them A method of automatically positioning a fume hood is also disclosed The system and the method can provide a more dependable operation than ever before without the need of a complex construction.

Abstract: The fume extraction system (10) includes a fume hood (12) located at the end of an articulated exhaust duct robotic arm (14) Three pairs of photoelectric sensors (34, 36, 38, 40, 42 and 44) are provided on the fume hood (12) to sense the presence of an electric welding arc (64) The system (10) includes a control unit (50) that generates command signals for the arm (14) based on signals received from the sensors so as to automatically position the hood (12) over the arc (64) and maintain a predetermined height distance between them A method of automatically positioning a fume hood is also disclosed The system and the method can provide a more dependable operation than ever before without the need of a complex construction.

Abstract: An exhaust system for fume extraction from a work area such as the vicinity of a welding gun is provided, having an articulted exhaust duct with a fume hood mounted at the forward end thereof. A signal emitter is mounted on the work tool, and three sensors are mounted on the fume hood, one at the front and one at each side so as to form a triangle. One motor is provided at the joint between the front and rear portions of the articulated exhaust duct, and two further motors are provided at the rear end of the exhaust duct. The first motor opens and closes the angle between the front and rear portions of the exhaust duct, and the second motor moves the rear portion of the exhaust duct backward and forward in the same vertical plane as that in which the front and rear portions of the exhaust duct move under the influence of the first motor. The third motor turns the entire assembly in an arc.