Abstract: The seam welding apparatus includes a pair of rotating electrodes, an electrode supporting frame, a distance measuring means, and a controller. The electrode supporting frame supports the pair of rotating electrodes. The distance measuring means is provided on the electrode supporting frame and measures a distance to an edge of the steel plate. The controller controls the robot to adjust a running direction of the rotating electrodes so that a deviation comes into zero when a distance actually measured by the distance measuring means deviates from a predetermined distance. Thereby, it is accomplished that the seam welding apparatus is downsized as well as uninfluenced by the surface state and/or shape of workpiece (steel plate).

Abstract: This seam-welding device carries out seam welding while repeating one cycle comprising a melting period, an interruption period, and a heating period implemented either before or after the interruption period. A welding current is applied between a pair of roller electrodes so as to form a welded part between workpieces during the melting period, the application of the current between the roller electrode pair is interrupted so as to solidify the welded part during the interruption period, and a heating current smaller than the welding current is applied between the roller electrode pair so as to heat the laminated body within a solidification temperature range of the welded part during the heating period. Consequently, even when the welding speed is increased, formation of cracks and spatter is effectively suppressed such that a high-quality joined product is obtained.

Abstract: In a seam welding method, a pressing force applied to workpiece by roller electrodes is reduced and an energization to the roller electrodes is stopped when the roller electrodes pass at least a portion where metal sheets are temporarily fastened together through spot welding, and the pressing force to the workpiece by the roller electrodes and the energization to the roller electrodes are restored after the roller electrodes have passed the spot welded portion.

Abstract: Shifts of a reference point C in a robot coordinate system among three postures of a seam welding apparatus 10 are found, and calibration data is obtained (STEP 1). Correction data is found from the calibration data based on deformation of elastic units 22a due to weight of the seam welding apparatus 10 in accordance with the posture of the seam welding apparatus 10 relative to a robot 20 (STEP 5). Teaching data is corrected based on the correction data (STEP 6).

Abstract: Distance to the upper face of workpieces W sandwiched between electrode rollers 15 and 16 is measured by a range sensor 41 that has a predetermined positional relationship with the electrode rollers 15 and 16 (STEPs 1, 3). Correction is made based on the distance found by the range sensor 41 by moving the pair of electrode rollers 15, 16 with reference to the workpieces W so that an angle Rx between a straight line L0 connecting centers of the pair of electrode rollers 15, 16 and the surface of the plurality of workpieces W is preset angle (STEP 5).

Abstract: This seam-welding device carries out seam welding while repeating one cycle comprising a melting period, an interruption period, and a heating period implemented either before or after the interruption period. A welding current is applied between a pair of roller electrodes so as to form a welded part between workpieces during the melting period, the application of the current between the roller electrode pair is interrupted so as to solidify the welded part during the interruption period, and a heating current smaller than the welding current is applied between the roller electrode pair so as to heat the laminated body within a solidification temperature range of the welded part during the heating period. Consequently, even when the welding speed is increased, formation of cracks and spatter is effectively suppressed such that a high-quality joined product is obtained.

Abstract: In a seam welding method, a pressing force applied to workpiece by roller electrodes is reduced and an energization to the roller electrodes is stopped when the roller electrodes pass at least a portion where metal sheets are temporarily fastened together through spot welding, and the pressing force to the workpiece by the roller electrodes and the energization to the roller electrodes are restored after the roller electrodes have passed the spot welded portion.

Abstract: Shifts of a reference point C in a robot coordinate system among three postures of a seam welding apparatus 10 are found, and calibration data is obtained (STEP 1). Correction data is found from the calibration data based on deformation of elastic units 22a due to weight of the seam welding apparatus 10 in accordance with the posture of the seam welding apparatus 10 relative to a robot 20 (STEP 5). Teaching data is corrected based on the correction data (STEP 6).

Abstract: It is an object of the present invention to provide a seam welding warpage prevention method and apparatus capable of preventing warpage caused by cooling contraction after welding, in a case where workpieces are different from one another in material and thickness, and thus not uniform in thermal contraction. In the seam welding warpage prevention method for welding a plurality of workpieces W1 and W2 that are not uniform in thermal contraction with respect to an energizing direction, the workpieces W1 and W2 are clamped with a pair of roller electrodes 23 and 33 while applying current. The welding is performed in a state where the roller electrode 33 that abuts on the workpiece W2 having higher thermal contraction is offset in an advancing direction ahead of the roller electrode 23 that abuts on the workpiece W1 having lower thermal contraction.

Abstract: Distance to the upper face of workpieces W sandwiched between electrode rollers 15 and 16 is measured by a range sensor 41 that has a predetermined positional relationship with the electrode rollers 15 and 16 (STEPs 1, 3). Correction is made based on the distance found by the range sensor 41 by moving the pair of electrode rollers 15, 16 with reference to the workpieces W so that an angle Rx between a straight line L0 connecting centers of the pair of electrode rollers 15, 16 and the surface of the plurality of workpieces W is preset angle (STEP 5).

Abstract: The seam welding apparatus includes a pair of rotating electrodes, an electrode supporting frame, a distance measuring means, and a controller. The electrode supporting frame supports the pair of rotating electrodes. The distance measuring means is provided on the electrode supporting frame and measures a distance to an edge of the steel plate. The controller controls the robot to adjust a running direction of the rotating electrodes so that a deviation comes into zero when a distance actually measured by the distance measuring means deviates from a predetermined distance. Thereby, it is accomplished that the seam welding apparatus is downsized as well as uninfluenced by the surface state and/or shape of workpiece (steel plate).

Abstract: The method of lap-welding of metal plates using a laser beam, wherein at least one of the metal plates is surface-treated, includes putting a metal plate on the other metal plate and forming a gap between the metal plates so that gas generated at the treated surface at the time weld can be dissipated therethrough. A surface-treated first work and a surface-treated second work are placed one on the other and clamped by a clamp with an opening of the clamp centered at the location on the first work to be welded. Then a laser beam is directed to the location to form a weld. The beam is then directed near the inner periphery of the opening to form a heated portion so that the heated portion deflects to form a gap through which the gas generated at the treated surface dissipates thereby reducing gas pressure.

Abstract: It is an object of the present invention to provide a seam welding warpage prevention method and apparatus capable of preventing warpage caused by cooling contraction after welding, in a case where workpieces are different from one another in material and thickness, and thus not uniform in thermal contraction. In the seam welding warpage prevention method for welding a plurality of workpieces W1 and W2 that are not uniform in thermal contraction with respect to an energizing direction, the workpieces W1 and W2 are clamped with a pair of roller electrodes 23 and 33 while applying current. The welding is performed in a state where the roller electrode 33 that abuts on the workpiece W2 having higher thermal contraction is offset in an advancing direction ahead of the roller electrode 23 that abuts on the workpiece W1 having lower thermal contraction.

Abstract: The method of lap-welding of metal plates using a laser beam, wherein at least one of the metal plates is surface-treated, includes putting a metal plate on the other metal plate and forming a gap between the metal plates so that gas generated at the treated surface at the time weld can be dissipated therethrough. A surface-treated first work and a surface-treated second work are placed one on the other and clamped by means of a clamp with an opening of the clamp centered at the location on the first work to be welded. Then a laser beam is directed to the location to form a weld. The beam is then directed near the inner periphery of the opening to form a heated portion so that the heated portion deflects to form a gap through which the gas generated at the treated surface dissipates thereby reducing gas pressure.

Abstract: The present invention relates to a position detection surveying device for detecting a position of a target, and more particularly to a position detection surveying device which is most suitable for an automatic surveying apparatus and, without using expensive acoustooptic devices, can be miniaturized and manufactured so that it saves the electric power. In the present invention, a light emitting means irradiates a target with a light which is sector-shaped in an up-and-down direction, and a light receiving means receives a reflected light from the target, and a rotating means rotates in a horizontal direction a portion comprising at least the light emitting means and the light receiving means, and a computational processing means is able to detect a position of the target in accordance with a light reception signal from the light receiving means.

Abstract: A surveying instrument, which comprises an object to be irradiated, a projection system provided on a range finder or on a range finding angle measuring instrument having a range finder and for emitting a laser beam toward the object, driving means for driving a laser emitting source of the projection system, and control means for controlling emitting condition of the laser beam via the driving means based on a distance data from the range finder to the object to be irradiated, whereby, in case there is a deviation between the preset distance and a distance measured by the range finder, the control means changes irradiation intensity of the laser beam, or in case there is a deviation between the preset distance and a distance measured by the range finder, the control means changes irradiation intensity of the laser beam and also changes time interval of the intensity changes according to extent of the deviation, and position information and instruction are transmitted to the object to be irradiated side using

Abstract: A method and apparatus for controlling an air-fuel ratio for an engine, in which a closed-loop control and an open-loop control are performed selectively in accordance with the operating condition of the engine. The closed-loop control determines an air-fuel ratio of the mixture to be supplied to a combustion chamber on the basis of the oxygen concentration within the exhaust gas. The open-loop control determines an air-fuel ratio of the mixture by modifying the air-fuel ratio determined in the closed-loop control in a manner that the former one is lean by a predetermined ratio than the latter one.

Abstract: An engine control apparatus having a microcomputer which controls an operating condition modifying means to modify the operating condition of the engine, wherein the absolute value .DELTA.C of the difference, C.sub.now -C.sub.old is calculated from a previously obtained basic amount of control C.sub.old, and a newly obtained basic amount of control C.sub.now, a correction coefficient K is determined which takes a value of 1 to nearly 0 as the .DELTA.C is increased, and then the C.sub.set ofC.sub.set =K.times.(C.sub.now -C.sub.old)+C.sub.oldis calculated as an actual basic amount of control.

Abstract: A fuel supplying system used in engine starting includes throttle valve means disposed in an intake air passage and metering valve means disposed in a fuel passage which extends from a fuel reservoir to a space of the intake air passage downstream from the throttle valve means. In order to obtain a required air-fuel ratio of a mixture determined in accordance with data representing states of an engine, in the fuel supplying system an opening degree of the throttle valve means which have a response delay is held constant and an opening degree of the metering valve means is adapted to be changed in accordance with a change of the required air-fuel ratio.

Abstract: An apparatus for enriching an air-fuel mixture supplied by a carburetor upon starting operation of an internal combustion engine comprises a fuel quantity increasing passage which is operative independent of main fuel supply system. The passage has an inlet communicated to a fuel supply source and an outlet opened at a location downstream of a throttle valve. The amount of fuel ejected from the outlet of the passage is controlled by a control signal which represents a product of a value variable in dependence on a suction vacuum, the rotational frequency of the engine and a value variable in dependence on the temperature of engine cooling water.