Abstract: A stand-off control apparatus for plasma processing machines which is capable of maintaining an optimum stand-off even when a processing speed varies. In a stand-off control apparatus for plasma processing machines which is provided with a microcomputer (4) for maintaining an optimum stand-off (h.sub.0) by moving a torch toward/away from a work so that an independently inputted arc voltage (V) agrees with a speed-corrected target arc voltage (V.sub.O(F)) obtained by correcting a target arc voltage (V.sub.O), which is stored in advance, for an independently inputted processing speed (F), the microcomputer (4) determines at the time of varying a processing speed (F) whether the speed is being accelerated, being decelerated or being kept unchanged, and provides that the speed-corrected target arc voltage (V.sub.O(F)) for the respective case is applied after the lapse of a corresponding delay time (.DELTA.t) which is independently stored.

Abstract: The present invention discloses a standoff control method and an apparatus for a plasma cutting machine capable of quickly correcting a deviation of the standoff with respect to a set value, keeping constant the standoff even if the cutting speed changes, preventing deterioration of the working efficiency even if a double-arc is generated, and properly detecting the use limit of the electrode. Standoff correction computing device (28) includes a reference voltage computation setter (36) for outputting a reference voltage between a workpiece to be cut and an electrode or a nozzle with respect to a predetermined standoff, an error computing device (37) for calculating the deviation of said detected voltage with respect to the reference voltage, and a correction quantity computing device (38) for outputting a vertical repositioning speed signal for the torch in accordance with the degree of the deviation.

Abstract: The present invention discloses a method of controlling torch height in plasma cutting arranged to monitor the cutting speed so that the optimum torch height is maintained and an excellent cutting quality is obtained even if the cutting speed changes. To this end, a base metal (2) is cut by a plasma arc (3) while a torch (1) is maintained at an optimum height (hc) from the base metal (2), and arc voltage (Vi) is read several times (i=1 to n) after the arc voltage becomes steady, their mean arc voltage (Vb) is calculated, a cutting speed (Fa) is read at the time of steady cutting, the means arc voltage (Vb) is corrected by this cutting speed (Fa) to obtain a target arc voltage (Vc) and the optimum height (hc) is maintained by this target arc voltage (Vc).

Abstract: This invention relates to a flexible robot arm comprising a plurality of disc-shaped elements arranged in a series so as to consist of a flexible arm, both surfaces of each of the elements being formed in convex having an arched opposed single curve so as to form contact surfaces, and a plurality of wire-like actuating devices for allowing the flexible arm to curve or bend in a desired direction. The flexible robot arm of this invention is directed to make motors for driving the actuating devices compact in size and light in weight and also a drive unit section compact in size and light in weight. The flexible robot arm includes two drive units each interconnected to the proximal ends of respective pairs of actuating devices (e.g. 3a and 3c, and 3b and 3d) disposed oppositely to each other on the diagonal and driven through rotary members (5a, 5b, 9a, 9b or 12a, 12b, 12c, 12d) each being rotated by one of the motors (8a, 8 b) in both the clockwise and the anti-clockwise directions.

Abstract: A flexible arm capable of smoothly effecting bending for an extended period and improving positioning accuracy comprises a plurality of vertically stacked units (1) consisting of one disc (5) which has projectingly curved contact surfaces on both sides in an axial direction, one support plate (4) which is fixed to a coaxial center hole of the disc and has a plurality of plate fitting surfaces (4a) disposed on both sides of the peripheral portion in the axial direction with their phases shifted from one another, two torsion plates which have a center hole for loosely accommodating the disc and fitting surfaces (19) around their peripheral portions fixed to the plate fitting surfaces of the support plate, and one intermediate plate (6) which has a center hole for loosely accommodating the disc and whose fitting surfaces (15) around its peripheral portion on both sides in the axial direction are fixed to the fitting surfaces of the torsion plates on the opposite side to the support plate.