Abstract: Pipe-welding apparatus with a centering device for centering the pipe-welding apparatus relative to a pipe which is to be welded to an end-plate. The centering device is provided with a tubular center part which supports two pairs of sleeves arranged axially next to one another, the one sleeve in each pair being rigidly connected to the center part and the other sleeve being slidingly displaceable along the center part. A number of balls located between the sleeves in each pair of sleeves is arranged to interact yieldingly with the mutually facing end surfaces of the pair of sleeves, the axial separation of which increases in the direction towards the periphery of the device. The displaceable sleeve is located in a spring sleeve which is mounted on the center part and encloses a spring arranged to press the displaceable sleeve towards the fixed sleeve, the spring sleeve being mounted at a fixed distance from the end surface of the fixed sleeve, which distance is smaller than the diameter of the balls.

Abstract: This invention relates to a method and apparatus for automatic multi-run welding of a joint such as a square butt joint, a V-type joint, or a U-type joint, etc. This invention incorporates a sensor which moves along the joint and which scans a number of points along portions of the joint. The points scanned are used to calculate the cross-sectional area of the portions of the joint and the cross-sectional areas are then used to determine welding parameters, such as weld speed and weld rod feed, for welding which is to be done in each of the joint portions. Thus, the joint is filled with weld material uniformly along its length despite deviations which may be inherent in the edges of the materials which are being welded.

Abstract: This invention relates to a method and apparatus for automatic multi-run welding of a joint such as a square butt joint, a V-type joint, or a U-type joint, etc. This invention incorporates a sensor which moves along the joint and which scans a number of points along portions of the joint. The points scanned are used to calculate the cross-sectional area of the portions of the joint and the cross-sectional areas are then used to determine welding parameters, such as weld speed and weld rod feed, for the welding which is to be done in each of the joint portions. Thus, the joint is filled with weld material uniformly along its length despite deviations which may be inherent in the edges of the materials which are being welded.

Abstract: A contact nozzle for a wire-shaped welding electrode for arc welding is designed as a contact tube in the front section and as a guide channel for the electrode in the rear section. The guide channel is formed by an open groove made in the nozzle body. The feed by the electrode is hindered in the rectilinear feed direction by a convex projection of the groove wall. Particles, dragged into the nozzle with the electrode, fall out of the open groove and therefore cannot displace the contact tube.

Abstract: A contact tip for supporting a consumable welding electrode and for supplying welding current thereto. The contact tip is generally rod-shaped and has a passage with a helical contact surface. The welding electrode is fed through the passage and makes electrical contact with the contact tip. Because of the helical contact surface, the passage never becomes constricted by cumulative deposits of dirt and extraneous matter from the welding electrode surface. Also, the helical contact surface, which axially extends at least one complete turn, has an unbending effect on the welding electrode, thus straightening the electrode. A distance "A" of the electrode axis from the contact tip axis may be chosen, as desired, considering the diameter of the welding electrode. Optionally, the contact tip may include a sleeve-like nozzle, to shield the contact tip from deposits of welding splatter.

Abstract: An apparatus is disclosed for the internal welding of an edge joint between a large main pipe and a small branch pipe, which pipes together form a pipe branch. The apparatus is equipped with a nozzle holder for a non-consumable electrode which forms an acute angle with the axis of the branch pipe, said nozzle holder being introduced into the branch pipe and being capable of axial displacement by means of an actuating mechanism. The nozzle holder is connected to a support holder for a frame attached to the branch pipe. The support holder and the nozzle holder are capable of rotation about the branch pipe. The radial gap between the electrode and the branch pipe is determined by the interaction with a sensor which follows the wall of the pipe. The axial gap between the electrode and the edge joint, that is to say the point of welding, is adjusted by means of a comparison between the arc voltage corresponding to the actual gap and a desired gap arc voltage.

Abstract: Power sources for welding applications and the like are provided in accordance with the teachings of the present invention. An inverter arrangement comprising a plurality of inverters, having inputs connected in series, receive portions of a d.c. load from a plurality of series connected smoothing capacitors. The smoothing capacitors are connected to form a voltage divider and apply the resulting portions of the d.c. load to the plurality of inverters. This enables the plurality of inverters to be dimensioned in a manner so as to withstand the smaller portions of the d.c. load resulting from the voltage division.

Abstract: Apparatus for the simultaneous manufacture of several chains by means of not less than three and not more than five operating stations (5-8) equally distributed about a circular course and serving successively to add a link to the chains and to perform the operations required to finish the link. A set of movable conveyors (11-14) equalling in number the operating stations carried by an annular supporting member (22) rotatable about the vertical axis of the course successively presents depending ends (1a-4a) of the chains to the operating stations. A set of stationary conveyors (15-18) receives the chains discharged by the movable conveyors and conveys them to points from which they can be withdrawn to localities remote from the manufacturing apparatus.

Abstract: A turning roll assembly for the supporting and rotating of a cylindrical object (5) has two pairs of two rollers sets which are axially displaced in relation to each other. A supporting roller of each of the roller sets is rotatably mounted about a horizontal axis (23) in a holder (15,20) which is swivable about an axis (16) situated in a normal plane to the axis of rotation of the object. At least three holders (15,20) are each mounted on its carriage (3). The carriages are freely movable on a foundation in the direction of the axis of the object. The assembly is provided with a mechanism (25,27,29) for each carriage which converts an axial movement of the carriage (3) to a swivel movement of the holder (15,20) about its swivel axis (16). Thereby the foremost end of the roller axis (23) in the direction of movement of carriage swivels backwards in relation to the direction of rotation of the object.

Abstract: A welding rectifier is connected to an a.c. power supply. The rectifier delivers a pulsating voltage which during a part of a period is too low to maintain the arc established between a welding electrode and a work. A main winding of an ironcored inductor is connected in series with the rectifier, the welding electrode and the work. An auxiliary winding is wound onto the iron core and connected in series with a capacitor. The auxiliary winding is connected to the main winding so that the two windings, when passed by a current, supply ampere-turns in the same direction. The auxiliary winding and the capacitor are connected in parallel with the main winding and the arc. The capacitor is also connected in series with a charging rectifier connected to the a.c. supply. The capacitor is discharged through the auxiliary winding and the main winding into the arc, when the voltage delivered by the welding rectifier is too low to maintain the arc.

Abstract: A sensor for detecting the relative position of a workpiece with respect to the tip of a welding or cutting torch, which is movable in optional directions by positioning devices, is provided with a sensing body in annular form which surrounds the tip and is adapted to make contact with the workpiece on any side of the central opening of the sensing body. An arm is attached to the sensing body and is displaced in a direction and to a degree corresponding to the displacement of the sensing body. The displacement of the arm is detected and a signal corresponding to that displacement is generated to reposition the welding head in response to the signal.

Abstract: A tubular filler rod or filler wire the metal sheath of which is composed of two members, to wit, an outer seamless tube and an inner tube consisting of a strip bent into tube shape and confining a compacted powder core. Also, a method of manufacturing a tubular, powder-cored filler rod or filler wire in which a metal strip is bent to form a trough which first is fitted with a powder composition and then closed to form a tube enclosing a core of the powder composition; the tube is slid into a second, seamless tube which is then submitted to a cold-drawing operation.

Abstract: A combined pivot joint and electric contact device between two welding current conductors forming part of the welding circuit of a resistance welder. The device is provided with a pair of contact plates extending at right angles to the joint axis and connected each to one of the welding current conductors. The plates are rotatable and axially displaceable with respect to each other. A yieldable thrust member urges the plates into engagement with each other. A channel provided in at least one of the plates has an outlet in the contact face of the plate and an inlet away from said face. Separation of the plates is effected by connecting the channel to a source of compressed gas to discharge a current of gas through the port.

Abstract: Submerged-arc spot welding apparatus has a carriage for supporting a welding means which is displaceable along a track disposed above a bed or table supporting the work. The carriage is provided with a pressure mechanism consisting of a pressure cylinder guided for motion in the carriage towards and away from the work, a piston in the cylinder having a piston rod attached to a thrust member which is moved into engagement with the work by the outward stroke of the piston. The corresponding backward thrust acting on the cylinder is taken up by stop means rigidly connected to and extending along the track. A stop on the carriage serves to take up the weight of the cylinder when the drive pressure is shut off.

Abstract: Device for feeding a consumable wire electrode. Two feeding units are mounted in tandem. Each of the feeding units is provided with a pair of rolls and coupled to a direct current motor driving one of the rolls in the pair. The two motors are connected in series.

Abstract: A tubular filler rod or filler wire the metal sheath of which is composed of two members, to wit, an outer seamless tube and an inner tube consisting of a strip bent into tube shape and confining a compacted powder core. Also, a method of manufacturing a tubular, powder-cored filler rod or filler wire in which a metal strip is bent to form a trough which first is fitted with a powder composition and then closed to form a tube enclosing a core of the powder composition; the tube is slid into a second, seamless tube which is then submitted to a cold-drawing operation.

Abstract: An arc welding apparatus for pulsed arc welding includes a silicon controlled rectifier and an uncontrolled rectifier the D.C. outputs of which are connected in parallel to a non-consumable electrode and a workpiece, respectively. The silicon controlled rectifier delivers a background welding current to the arc between the electrode and the workpiece. The D.C. outputs of the uncontrolled rectifier are connected in series with transistors controlled by signals to regulate the flow of current supplied from this rectifier to the arc to provide periodically recurring welding current pulses of predetermined length and amplitude to the arc in addition to the background welding current delivered by the silicon controlled rectifier.