Abstract: A wrist for an industrial robot with a movable arm is arranged at the outer end of the robot arm and comprises partly a first housing mounted at the end of the arm and journalled for rotation about a first axis which is substantially parallel with the longitudinal axis of the outer part of the arm; partly a second housing journalled in the first housing for pivoting about a second axis which is substantially perpendicular to the axis of rotation of the first housing; partly a tool holder journalled in the second housing for rotation about a third axis which is substantially perpendicular to the second axis; and partly drive and power transmission devices for generating motion in the first and the second housing as well as in the tool holder about the first, the second and the third axis, respectively. The first housing comprises two interconnected sections which are pivotable in relation to each other about a fourth axis extending substantially perpendicularly both to the first axis and to the second axis.

Abstract: Electrically conductive refractory bricks, containing particles (e.g. flakes) of graphite or other electrically conductive material are pressed into the desired final shape but include a plurality of passages, none of which passes completely through the brick. The passages each extend substantially perpendicularly to the predominant direction of the conducting particles.

Abstract: A forming press of the pressure cell type comprising a press stand with two opposing force absorbing elements defining between them a working space into which a trough with forming tools and workpiece can be inserted; a press plate in communication with a pressure medium source; a diaphragm forming together with the press plate an expansible pressure cell; and side pieces extending along the side surfaces of the working space while keeping the diaphragm in abutment against a sealing ring disposed around the periphery of the diaphragm, said sealing ring in turn abutting against the press plate, providing thereby a quicker and simpler diaphragm exchange as compared to prior art constructions by the side pieces being turnable so that when upwardly swung, their long sides abut against the underside of the diaphragm, and by means for moving the unit formed of upwardly swung side pieces and diaphragm out of the working space; the invention also including a process for changing diaphragms in said forming press.

Abstract: The invention relates to an industrial robot of the kind comprising a body and an arm system pivotally journalled thereon. In order to achieve an improved and extended working range in a vertical space underneath or above the robot, the arm system is supported in the body via a substantially fork-shaped bearing bracket. Linear actuators intended for the operation of the arms are pivotally journalled in the bearing bracket so that, when the arm system assumes its neutral position, the actuators will be oriented primarily transversely to the longitudinal axis of a body and substantially parallel with the first arm pivotally journalled in the bearing bracket. Both actuators are disposed between the body and the first arm in all positions of the arm system.

Abstract: A level meter in a mold for continuous casting has an assembly including a continuous casting mold, an annular multi-phase electromagnetic stirrer surrounding the mold, and a source of radioactivity projecting a beam of radiation through the mold, a detector for the beam being positioned on the opposite side of the mold. To permit the stirrer to have a height providing optimum stirring, two of the coils of the stirrer have portions of reduced height forming spaces opposite to each other and through which the beam can be projecting to the detector. Therefore, the height of the stirrer need not be reduced to provide for the beam and detector arrangement.

Abstract: A continuous casting apparatus has a plurality of non-magnetic rollers which contact a side of a continuously cast traveling strand. To support each roller against bending, the roller is journaled at its opposite ends and also at least at one interposed position between its ends to define roller lengths between each two of the bearings. Inductive stirrers providing traveling magnetic flux fields extending for the full extent of each length in each instance, are positioned on the outside of such roller length so as to project flux fields without interruption through the roller between its journaled ends and the interposed journaling position. Uniform uninterrupted fields are provided regardless of the strand's width.

Abstract: A power transmission device includes a rotatably mounted drive screw, a nut element which is movable along the drive screw, and a pair of links which connect the nut element to a driven member. The links are rigidly connected to each other by a torsionally stiff member to prevent relative angular movement therebetween.

Abstract: An arrangement in an industrial robot for driving translatory motion of a unit which is mounted in a gimbal-type suspension having two mutually perpendicular axes. A motor with associated resolver is mounted in the pivotable frame of the gimbal-type suspension, the frame being capable of being swung in one direction. The motor drives a pinion which meshes with a rack by a shaft, the shaft also constituting one journal of the machine part in which the translatorily movable machine part is movably arranged. The shaft is rotatably journalled to both the frame and the machine part through each of its bearings.

Abstract: A DC arc furnace having an electrically conductive hearth adapted to contain a melt, and at least one arcing electrode above the hearth and adapted to form a heating arc with the melt when the hearth and electrode are supplied with DC power; the hearth having a wear lining directly contacted by the melt and formed by refractory material through which electrical conductors extend from the bottom of the wear lining to its top. A metal plate under the wear lining electrically connects with the conductors and is supported by one or more electrically non-conductive layers of refractory. Power connection to the wear lining is via the plate and a connection with the periphery of the plate.

Abstract: A ladle or tundish has a side wall comprising a refractory lining adapted to be contacted by molten metal, and a concrete wall surrounding the lining and reinforced by metal wires, the side wall being free from a metal shell. Therefore the side wall is relatively permeable to the field of an induction heating coil on the outside of the side wall.

Abstract: A DC arc furnace comprising a furnace vessel having a hearth and a side wall extending upwardly from the hearth, conductive means for conducting DC through the hearth from its outside to a melt in the hearth, an arcing electrode, a substantially horizontal arm having a holder holding the electrode substantially vertically above the hearth, a substantially vertical mast from which the arm extends, and means for connecting DC positively to the conductive means and negatively to the electrode so as to form an arc between the electrode and the melt and producing an arc flare to which the side wall is exposed; wherein the improvement comprises means for connecting the arm to the mast so as to permit the arm to be adjustably moved longitudinally to different positions and means for mounting the mast so it can be adjustably rotated to different positions about its axis, whereby the electrode and its arc can be located at different positions horizontally to the side wall.

Abstract: A control system for a DC arc furnace having a hearth adapted to contain a scrap or metal charge, an arcing electrode, a thyristor converter having a connection with the electrode and charge to form a circuit, current comparing comparator for comparing current in the circuit with a set-point current of fixed value and controlling the thyristor in response to the comparison so as to cause the current in the circuit to substantially equal the set-point current value, electrode positioning apparatus for moving the electrode up and down relative to a charge in the hearth, and a voltage comparison comparator for comparing the voltage in the circuit with a set-point voltage of fixed value and controlling the electrode positioning apparatus in response to the voltage comparison so as to keep the voltage in the circuit substantially equal to the set-point voltage.

Abstract: A DC arc furnace including a hearth adapted to contain a melt and having a melt electrode which is only effective when covered by the melt, an enclosure for the hearth including a roof over the hearth, at least one arcing electrode depending downwardly through the roof and adapted to initially melt a charge of solid metal on the hearth and thereafter the resulting melt, and at least one starting electrode through which electric power is transmitted to the charge of solid metal until it is melted down by the arcing electrode to enough melt to cover the melt electrode; the starting electrode or electrodes depending downwardly through the roof at a position horizontally offset from the arcing electrode and being adapted to be moved downwardly so as to press on the charge of solid scrap on the hearth until the charge is melted down by the arcing electrode so as to cover the melt electrode and thereafter to be moved upwardly free from the charge.

Abstract: A furnace for melting and melt-heat retaining of metals has two horizontal interspaced furnace vessels which form a melt chamber and each having a side wall facing the side wall of the other furnace vessel, each side wall having an opening horizontally aligned with the opening of the side wall of the other furnace vessel. A single inductor is positioned between these side walls and is formed by an integral block of ceramic having opposite ends abutting the outside of the side walls. The block has a transverse through-hole and two longitudinal through-holes straddling the transverse through-hole and open to the two furnace vessels so that they intercommunicate. The inductor has a core with an energizing coil and having a leg extending through the transverse hole. When the energizing coil is powered a melt in the two longitudinal through-holes is heated by an induced circuit which extends into and through melts in the two furnace vessels.

Abstract: A method for continuously pouring molten metal in an initially substantially unfilled tundish having a channel-type inductor having a channel opening into the bottom portion of the tundish, is done by starting the pourings and the continuous sequential steps of applying power to the inductor when its channel is first covered by the poured metal to form a melt level and the static pressure of the metal is low and while increasing the power rapidly so as to cause incipient pinching in the channel and then momentarily rapidly reducing the power so as to prevent pinching; as the metal level further increases so that the metal's static pressure further increases, again increasing the power rapidly so as to again cause incipient pinching in the channel and then again momentarily rapidly reducing the power so as to prevent pinching; and continuing these sequential steps until the tundish is filled.

Abstract: For controlling a work process carried out by means of a robot (RB), instructions are stored both relating to the positioning of the robot and relating to the very process to be accomplished. The process instructions are stored in the form of process stage instructions (SPS, SPM and SPE) comprising(a) process start stage, during which the process is initiated (the arc is struck, for instance, when arc welding is involved) and the relative movement between object and robot can be started;(b) process main stage, during which the actual process is carried out; and, at least when the process is not directly followed by a further process;(c) process terminal stage, during which the process is terminated (the arc is broken, for instance, when arc welding is involved) and the relative movement between object and robot can be stopped.

Abstract: A high voltage semiconductor valve has a plurality of electrically series-connected semiconductor elements, for example thyristors or diodes. These are designed for pressure contact connection and for double-sided cooling and are arranged alternately with liquid cooling bodies in a stack. At least some of the resistors included in the voltage divider of the valve are arranged with their resistive portions located in a passage in the cooling body between the contact surfaces for the two adjacent semiconductor elements.

Abstract: The present invention relates to a technique or method for stirring molten steel, wherein molten steel charged in a mold for continuous casting is circulated in a smooth flow in order to promote the degassing of the steel as well as to prevent the formation of surface defects on the cast steel. In order to carry out such desirable stirring, the present invention provides for a plurality of electromagnetic stirrers (capable of applying different magnetic field intensities) to be arranged along both long side walls of the casting mold so that the circulating flow of the molten steel can be accelerated or decelerated (depending upon its position) to form a smooth flow.

Abstract: An elongated electric bushing for a transformer, reactor, or the like is provided with a flexible intermediate flange (3) which comprises a plurality of spring devices (28) oriented in the longitudinal direction of the bushing, and a cardan assembly (11) for taking up longitudinally directed forces arising in case of an earthquake.

Abstract: An apparatus for contact-free sensing of a moving coherent mass of material, for example a stream of molten glass, comprises first sensing means for producing first output signals for determining the speed of advance of the material past the sensing apparatus and second sensing means for producing a second output signal related to a dimension, e.g. the diameter, of the material transverse to its direction of advance. The sensing apparatus further includes optical means comprising a common objective lens for supplying radiation focussed from the material being sensed to both said first and second sensing means.