Abstract: In an electrode for a plasma arc torch, an electrode member (1) composed of either one of homologous elements of hafnium, zirconium or titanium, or a mixed material of these elements is embedded into a front end portion of an electrode body (1a) and brazed and joined thereto by a brazing material, the electrode is characterized in that the electrode member and the electrode body are brazed by a brazing material (14a) including no copper component.

Abstract: A plasma torch, capable of cutting in a dross free state, is made possible by increased energy density of the arc jet. The operation efficiency is not reduced even with a low operating gas flow rate, since the arc jet can be stably maintained in the plasma torch. The torch has a high double arc resistance and excellent durability. This is realized by forming a velocity reduction space N from near a lower end (3b) of the electrode (3) to a nozzle (9) at the front end of the plasma torch (1), the velocity reduction space being used for reducing the axial velocity component of the operating gas which flows along the outer periphery of an electrode (3). The velocity reduction space (N) is cylindrically shaped, and the diameter (Dd) of the cylindrical shape is larger than the diameter (da) of a lower end (3b) of the electrode (3).

Abstract: A plasma torch can produce a uniform and intense swirl in the operating gas, and as a result further stabilize the output of the plasma jet, which results in good cutting quality, so as to extend the life of consumables or the like. This is achieved when jet ports (3) from which operating gas G is ejected are positioned such that in a transverse cross-section (2A) of a swirler (50) including the jet ports (3), a relationship between a diameter D of a swirler chamber and a minimum distance (d) from a line (2b), which is tangent to the diameter D of the swirler chamber and parallel to a projected line (3c) of an axis (3b) of the jet hole (3a), to the side end (2c), of the side of the jet port (3) adjacent to the tangential line (2b), is represented by 0<d/D.ltoreq.0.03.

Abstract: The data input device comprises a tablet portion made of a two-dimensional position-sensitive photodetector and a planar display element laid one on the other, and a light emitting pen forming a light spot on a light-receiving surface of the position-sensitive photodetector. The locus of the movement of the light emitting pen is displayed on the surface of the planar display element at correspond positions in accordance with the output of the two-dimensional position-sensitive photodetector, and the contents of the display provided on the planar displaying element are allowed to be delivered for subsequent processings.