Abstract: An automated welding system is provided for welding a workpiece. The system includes a multiaxially movable arm, a fiber optic cable, a laser source, a focusing head, a focus lens, and a shield. The fiber optic cable is coupled to the arm. The laser source is coupled to the fiber optic cable and configured to supply laser light thereto. The focusing head includes a first end, a second end, and a passage extending therebetween. The shield has an inlet, an outlet and a cavity formed therebetween, and each of the inlet and the outlet has a diameter. The shield inlet is coupled to the focusing head and the shield inlet diameter is greater than the shield outlet diameter. The shield outlet diameter is sized to provide an opening through which the laser beam exits and prevents substantially all particles external to the focusing head passage from entering therein.

Abstract: An exhaust muffler (20) for an internal combustion engine (25) includes a tapered tube (28) and an outer tube (40) axially aligned with and surrounding the tapered tube (28) so that an annular passage (42) is formed between the tapered tube (28) and the outer tube (40). The tapered tube (28) has an exhaust inlet end (30) for receiving exhaust gases (76) from the engine (25) and an exhaust outlet end (34). The outer tube (40) has an air inlet end (50) for receiving air (49) external to the engine and an air outlet end (52). The external air (49) flows in the annular passage (42) toward the air outlet end (52). The flow of the external air (49) creates a low pressure region (54) downstream of the exhaust outlet end (34) to accelerate the receipt of exhaust gases (76) from the engine, and elliptical holes (62) in the tapered tube (28) allow the smooth flow of exhaust gases (76) from tapered tube (28) to mix with the external air (49) to achieve effective noise attenuation.