Abstract: High resistance ground faults on a transmission line of an electrical power transmission network are detected with the aid of a device comprising a travelling wave model of the line located in measuring stations (P, Q) at either end of the line, which permits the voltage distribution along the line, seen both from P and from Q, to be obtained. A voltage .DELTA.U.sub.Qp is formed as the difference between a votlage in station P, calculated in the travelling wave model in Q, and the corresponding voltage one period earlier. A voltage .DELTA.U.sub.Pp is formed as the difference between a voltage calculated in the travelling wave model at P and the corresponding voltage one period earlier. The corresponding voltage differences .DELTA.U.sub.Pq and .DELTA.U.sub.Qq are calculated for station Q. The voltage difference .DELTA.P is then formed as the difference between .DELTA.U.sub.Qp and .DELTA.U.sub.Pp, and the corresponding .DELTA.Q is formed as the difference between .DELTA.U.sub.Pq and .DELTA.U.sub.Qq.

Abstract: A method for location of a fault on a transmission line in a network for distribution and transmission of electric power uses a travelling wave model of the transmission line positioned in measuring stations (P, Q) at either end of the transmission line, to obtain the voltage distribution along the transmission line, seen from both station P and station Q. A voltage .DELTA.U.sub.Qp is generated as the difference between the voltage in station P, calculated in the travelling wave model in station Q, and the corresponding voltage one period/half period earlier. A voltage .DELTA.U.sub.Pp is generated as the difference between the voltage, calculated in the travelling wave model in station P, and the corresponding voltage one period/half period earlier. The corresponding voltage differences .DELTA.U.sub.Pp and .DELTA.U.sub.Qq are calculated for station Q. The voltage difference .DELTA.P is then generated as the difference between .DELTA.U.sub.Qp and .DELTA.U.sub.Pp and the corresponding voltage difference .DELTA.

Abstract: A weld seam tracker for a welding robot has an optical sensor (4) for sensing the position of the seam and controlling the movement of a welding torch (10). The sensor (4) includes a light source, for example a laser, and a position-sensing detector. The sensor (4) is rotatably mounted at a housing (1) mounted on the robot hand (3) and is operated by a motor (6) arranged in the housing (1). A heat shield (40) with a window (42, 43) for the scanning light protects the sensor (4) against spatter and heat radiation. The welding torch (10) is mounted in a through-hole in the housing (1) and is surrounded by the sensor (4). Compressed air for cooling the sensor (4) is conducted to said sensor (4) via a gas-tight space (23) in the housing (1). Part of the cooling air is led out through a sleeve-formed screen (46) at the window (42, 43) of the heat shield ( 40), whereby fumes etc. are blown away from the visibility range located nearest the window.

Abstract: The invention relates to an industrial robot of a so-called agile type which has a lower arm (16) with double-sided journalling in a stand (12) consisting of two separated, upright parts (12a, 12b), the arm (16) being pivotable in the space between the stand parts. A pivot shaft (24) for pivoting the upper arm of the robot via a crank and a parallel link rod from one of the stand parts (12a) and through a lead-in opening (28) in the lower arm (16). From the other stand part (12b) there extends a drive shaft (30), which is substantially coaxially opposite to the pivot shaft (24) of the crank (22) and which is connected to the lower arm (16).

Abstract: A device for mechanically resetting, by means of a simple manipulation, an optional number of status indicators of the type consisting of an electromagnet with an iron core, a magnetizing winding and some form of permanently magnetized indicating disk capable of rotating through 180.degree.. The device comprises a rail made of a non-magnetic material and being formed so as to enable a desired number of indicators to be mounted side-by-side. The rail has such a profile as to enable a shuttle with a corresponding profile to be in engagement with and be guided by and slide on the rail in its longitudinal direction. The shuttle is provided with a permanent magnet as well as with a pole piece mounted so as to form, together with the core in the electromagnet of each indicator, a magnetic circuit when the shuttle is pushed over the respective indicator whereby the rotatable indicating disk is influenced and is reset to indicate the reset position.

Abstract: A damping device in a bogie of a railbound freight car has good ride properties independent of the load carried by the car by making the damping device with friction wedges of triangular cross-section, an upper surface of which confronts an adjoining load-supporting bolster beam and is joined thereto through a tertiary spring element of high stiffness in the vertical direction and of relatively low stiffness in the lateral direction. A lower surface of each friction wedge adjoins the upper side of the respective bogie suspension unit.

Abstract: A press for shaping a sheet metal blank in a cavity with a forming tool which determines the shape of the finished product. The sheet is pressed against the tool by a diaphragm which is influenced by a pressure medium on the side facing away from the cavity. The forming tool consists of an inexpensive casting material supported in a cup-shaped container. The space between the bottom and sides of the container and the bottom and sides of the cavity is filled with an elastic material.

Abstract: A torque transducer which is constructed so as to be protected from an overload includes a measuring axle which extends through a housing and a take-up axle which also extends through the housing in parallel with the measuring axle. The portion of the measuring axle within the housing includes two spaced apart gear wheels which are respectively engaged with backlash with gear wheels on the take-up axle, the gear wheels on the measuring axle being larger in diameter than the gear wheels on the take-up axle. When the measuring axle is subjected to excessive torque, such that the portion thereof within the housing twists sufficiently, the gear wheels on the measuring axle will engage with the gear wheels on the take-up axle to transfer the excessive torque to the take-up axle.

Abstract: A cylindrical gear unit which includes a gear housing, a gear pinion and a gear wheel, the gear pinion being fixed to a shaft which is rotatably journalled in bearings supported by at least one bearing support. One of the bearing supports comprises a sleeve in which a roller bearing is fixedly mounted, a fixing plate supported by the gear housing, as well as a disc-shaped rib portion which interconnects the sleeve and the fixing plate. The rib portion extends substantially along the entire length of the sleeve and the fixing plate and is substantially parallel to a tangential plane on the contact line between the gear pinion and the gear wheel. In addition, at least one stop face for the sleeve is arranged at a small distance from the outside of the sleeve on at least that side of the sleeve facing away from the gear wheel.

Abstract: A torque transducer with neutral point compensation has a measuring axle formed as a hollow member inside which a slender torsion spring is axially arranged to internally load the hollow member. With this device a constant torque load on the measuring axle can be set with such a direction and magnitude that the zero voltage output from the torque transducer represents zero external torque.

Abstract: When using an industrial robot together with a tool which is fed by a fluid, for example a nozzle for water jet cutting, the feed conduits often restrict the orientation capacity of the robot. This is avoided by providing a conduit which extends inside the robot arm and the wrist and comprises swivels, so that the parts of the wrist are able to rotate relative to each other unobstructed by the conduit.

Abstract: For the manufacture of an electrically conducting layer in the form of a coating on a base or in the form of a free bearing film, a liquid product is prepared consisting of water, a water-soluble polymer dissolved therein, a pyrrole compound dissolved in the water or present therein in undissolved state in the form of pyrrole, N-methylpyrrole or a mixture of pyrrole and N-methylpyrrole and a substance dissolved therein, such as a ferric compound, with the ability to give an electrically conducting polymerized pyrrole upon polymerization of the pyrrole compound. When the pyrrole compound in the liquid product has been transformed into a polymerized pyrrole, the liquid product is applied on a base and the water is thereafter brought to depart while leaving a layer on the base. The layer can be left as a permanent coating on the base or be removed from there while forming a free bearing film.

Abstract: A method and a device for distance protection and location of a fault point on a transmission line based on voltage waves emitted from a measuring point towards a fault point and corresponding waves reflected from a fault point, which are included in a travelling wave model of a transmission line. At certain regular intervals, a measurement is effected of the instantaneous values of the current and the voltage at an end point of the transmission line, for example at a station. Based on these measured values, and with the aid of the travelling wave model, it is possible to calculate the voltage at a number of control points along the transmission line. If the line is energized and the calculated control voltages at two control points have different signs during a time longer than a time corresponding to normal phase difference between the two voltages, there is a fault on the line between these points.

Abstract: A current limiter for high voltage utilizes the high migration velocity of an arc for rapidly inserting at least one pair of resistive runner rails upon a short-circuit in a circuit. To be able simultaneously to fulfil the demands for a high energy absorption capacity and sufficient resistance per unit of length of the runner rails, the runner rails are made of a relatively thin, insulated tape of an electrically conductive material, which is folded and packed to form a solid resistance package. Between the two runner rails in each pair of rails there extend two parallel walls of insulating material, which form between them a narrow gap for the arc. The magnetic field in the gap is reinforced with the aid of a magnetic core and/or current loops.

Abstract: An optical position-measuring sensor has a monolithic structure which includes at least two masses of photoluminescent material, which on excitation emit photoluminescent light with non-identical spectra. The at least two masses are supported in the sensor by a resilient part (e.g. a beam or diaphragm), the deflection of which determines the wavelength distribution of the luminescent light which is coupled into an optical wave conductor (e.g. a light fiber) terminating in the sensor.

Abstract: The invention relates to an apparatus for simultaneous casting of at least two casting moulds or balls. The apparatus comprises a carriage which is movable in the direction of a casting line and is provided with two gutters for transferring molten metal from respective furnace spouts to respective sprues. At least one of these gutters is adjustable in the longitudinal direction of the line.

Abstract: As overvoltage protection for a series capacitor (C1-C5) in a high-voltage network a voltage-dependent resistor (Z6), built up of metal oxide varistors, is arranged in parallel with the capacitor. In parallel with the resistor there is a spark gap means consisting of two series-connected spark gaps (G1, G2) for shunting the resistor in case of overload thereof. The energy for triggering the spark gap means is obtained from an auxiliary capacitor (C5), which is charged during operation, and is supplied to one of the spark gaps (G2) via a switching means (T1, T2), controlled by an overload detector (CU), and a pulse transformer (TR). A metal oxide varistor (Z5) is connected in series with the high voltage winding of the transformer. The transformer is connected so that the triggering pulse is in opposition to the voltage across the series capacitor.

Abstract: A robot wrist is built up of three rotatable tubular wrist parts arranged one after the other, the axes of rotation of the first and the second part intersecting each other and the axis of rotation of the third part intersecting the longitudinal axis of the third part. Three mirrors are arranged inside the wrist, so that a light beam arriving along the axis of rotation of the first part passes unrefracted through the wrist irrespective of the rotary positions of the three wrist parts. The wrist enables processing by laser of workpieces with no restriction of the orientation capacity of the wrist.

Abstract: A robot installation in a production line includes at least one robot (1) of pendulum type, the arm system (10, 14) of which is pivotable about at least one axis (12). The secondary arm (14) of the robot and a counterweight (16) are so displaceably arranged on the primary arm (10) of the robot that the centre of gravity of the arm system lies on or in immediate proximity to the pivot axis (12) independently of the position of the secondary arm (14) on the primary arm (10). To this end, the counterweight (16) and the secondary arm (14) are movably interconnected by means of a rope (18) running around rope wheels (20) at the ends of the primary arm (10). When mounting several robots of this kind on a stand (34, 35) positioned across the production line (31), the robots are mounted symmetrically in pairs on opposed side walls of the overhead stand part (35).