Abstract: An assembly is provided for mounting on an end of a robot arm actuator as an integral spot resistance welding gun and transformer unit. A gun slide support bracket is connected to the transformer and serves to provide a mount for a sliding gun cylinder having a piston connected to one of the jaw electrodes. The lower jaw is removably connected to the cylinder. Roller shunts are used to provide electrical connection between secondary terminals on the transformer and the two electrodes. A proximity switch assembly is advantageously utilized to provide signals to the robot controller indicating a fully retracted position of the jaws.

Abstract: The specification discloses a lightweight, compact welding transformer particularly well suited for robotic applications. The transformer includes coplanar secondary pads, a parallel common bus, and a secondary coil having turns each including a first end coupled to the common bus and a second end extending through the common bus and coupled to one of the secondary pads. The transformer further includes planar diodes abutting the secondary pads opposite the coil and a planar rectified bus abutting the diodes to sandwich them against the secondary pads.

Abstract: A transformer system for resistance welding intended for installation on robotic devices comprises an auto transformer having a tap selection switch connected through electrical conductors to an isolation welding transformer located at the end of the robotic arm. The auto transformer is uniquely selected for the maximum efficiency thereof and the optimum reduction in the size of the conductors between the transformers. The isolation welding transformer is also optimally sized due to the reduction permissable by the previous interposition of the auto transformer in the welding system. Moreover, the isolation welding transformer comprises primary and secondary coils formed from tubular members each of which is cooled by a fluid coolant. Utilization of refrigerated coolant permits further reduction in size and mass, and increases electrical efficiency because of the unique design of the isolation welding transformer in which both primary and secondary windings are cooled by such fluid coolant.

Abstract: A welding gun apparatus having a gun bracket, a pair of arms pivotally mounted on the bracket, a transformer mounted on the bracket, and a pressure applying mechanism on the bracket for opening and closing the gun arms; characterized in that the gun bracket comprises a frame which extends longitudinally from a front pivot portion for pivotally supporting the gun arms to a rear portion, the transformer being positioned in and fixed to the frame between the front pivot portion and the rear portion.

Abstract: A welding apparatus includes an improved transformer having a U-shaped secondary winding movable therein and guided by means external to the transformer. One leg of the U-shaped winding is flexibly connected to a first welding electrode carried by the piston rod of a jack having a jack body and piston adapted for movement relative to one another. The other leg of the winding is rigidly connected to a second welding electrode which is also rigidly secured to the jack body. The jack is movably mounted on guide means external to the transformer. Thus, as the second electrode is moved during a welding operation, the secondary winding is guided within the transformer by the movement thereof.A method of welding includes moving the first electrode toward a workpiece so as to contact the same and thereafter moving the second electrode to clamp the workpiece for welding, the secondary winding being guided by the movement of the second electrode.

Abstract: Apparatus for resistance welding is provided. The apparatus includes a transformer, to an output face of which resistance welding electrode holders are connected. The output face has two terminal blocks with threaded openings to receive fasteners for several different designs of electrode holders. The welding electrode holders, being directly connected to the transformer, eliminate the usual heavy cables located between the welding electrode holders and the power source, thereby increasing efficiency through reduction of impedance and secondary loss. The transformer and electrode holders are essentially one unit which can also be moved about to different locations. The welding apparatus is also versatile and compact to meet various applications.

Abstract: A transformer for electric welders, especially welders having a welding gun secured to a robot arm, comprises a small lightweight loop core having first and second substantially C-shaped sections abutted together at their free ends with primary and secondary windings coaxially wrapped about one pair of abutting shanks. The secondary winding comprises an elongated flat sheet wrapped around abutting shanks of the core and has projecting tabs extending from opposite sides of the sheet. A primary winding comprising a plurality of coil sections is coaxially wrapped about the secondary winding whereby the secondary winding is substantially entirely coupled to the primary winding. The windings are encapsulated in a dielectric material such as a synthetic polymer resin. The transformer is preferably connected to a high frequency electrical power source.

Abstract: An internal apparatus for flash welding pipes together in end to end relationship both under factory conditions and in the field, for example in laying trunk pipelines, comprises an elongate supporting member carrying an axially movable clamping assembly with electrode jaws for clamping one pipe, an axially immovable clamping assembly with electrode jaws for clamping the other pipe, and a doughnut-type welding transformer. The welding transformer is disposed at the side of the axially immovable clamping assembly, which is distant from the joint. The axially immovable clamping assembly is mounted on the elongate supporting member in a manner to provide an annular clearance therebetween such that there are extending therethrough two coaxial contact tubes, which are electrically insulated from one another and connect the welding transformer with the electrode jaws, whereby in operation a welding circuit is established.

Abstract: An improved electrical resistance welder which provides the same welding current at the welding electrodes as prior welding device while requiring less input current, and providing lower reactance, less weight and overall increased efficiency. The resistance welder includes a transformer having a pancake type primary winding formed of a metal tube thrugh which a coolant is flowed. Portions of the primary winding are adjacent the transformer secondary and thus the primary winding also functions as a heat sink to cool the secondary.

Abstract: A pair of thermoplastic coated, paramagnetic metal sheets (26 and 27) are moved from a position within a first bus loop half (28) to a position within a second loop half (29) while a pair of electrodes (31 and 32) are cyclically moved to engage and weld a line of spots along the sheets. Constant current pulses are cyclically applied to the welding electrode (32) and through the loop halves (28 and 29) to the welding electrode (31). The current divides in the loop halves in proportion to the positionment of the metal sheets in the respective loop halves so that eddy current and hysteresis losses are held to constant minimum values. Auxiliary heaters (43 and 44) act to heat the electrodes to melt and displace the thermoplastic coating along the line of engaged spots prior to the cyclic application of the weld pulses.

Abstract: A resistance welding system having a low-inertia movable welding head coupled to a stationary welding transformer which is of low mutual reactance. Through an appropriate timing circuit and control, a high-energy pulse of current, of very short time duration, is transmitted through the welding transformer to the movable welding head. The welding head, which contacts a projection on overlapping components, effects a rapid welding of the components, and the welding head rapidly follows up the melting of the projection due to its low inertia.

Abstract: In an electrical resistance welder, whenever a material to be welded approaches the welding electrodes, a start signal is produced, so that welding current is supplied to the welding transformer in one direction for a certain period of time set by a time limit circuit, with the polarity changing in response to the start signal, whereby, even if materials are repeatedly fed for welding at high speed, they can be positively welded in a uniform manner.

Abstract: A resistance welding machine for progressively welding each of a succession of transverse wires to longitudinal wires at a transverse welding station to and through which the longitudinal wires are incrementally advanced, the machine having a welding unit including a carriage mounted above the welding station for intermittent and reversible movement transversely of the machine and longitudinally of the welding station, a transformer vertically reciprocable in the carriage by a power unit mounted thereabove on the carriage, and a ram suspended from the transformer for movement in unison therewith and mounting for limited relative vertical movement a welding head carrying a front welding electrode, and a vertically movable guide bar and stationary platen, both electrically conductive and mounted independently of the welding unit, the guide bar below the ram and in advance of the welding station for guiding the longitudinal wires thereto and the platen underlying and supporting the longitudinal wires below both

Abstract: A spot welding machine having a pair of electrodes connected to the transformer by a pair of closely mounted shunts spaced less than one quarter of an inch to reduce both the current loss and the reactive forces.

Abstract: A method to control the welding transformer residual magnetizing current which normally continues circulating in the secondary circuit at the end of each welding pulse until the tips are opened. By utilizing a firing delay of the last half cycle in each welding pulse that brings the algebraic sum of the volt-seconds applied to the transformer to zero at the end of each welding pulse, the residual secondary current is nulled. This alleviates magnetizing current problems which occur in multiple pulse welding.

Abstract: A welder arranged inside pipes to be welded comprises a housing with the longitudinal axis thereof matched with the axis of the pipes. On the housing are a welding transformer and two mechanisms clamping the pipes, each having a drive moving the mechanism along the axis of the housing, and each being electrically connected to the transformer. The housing has mounted thereon a pipe flashing and upsetting mechanism with its own hydraulic drive, kinematically coupled to one of the pipe clamping mechanisms, a hydraulic pump supplying fluid to the drives, and a mechanism driving the welder along the pipes' axis. The housing carries two bearing discs secured at opposite ends and three clips mounted on roller supports and movable along the housing's axis. Two clips are incorporated in the first and second clamping mechanisms, respectively, and the third is part of the flashing and upsetting mechanism.

Abstract: According to the invention, the ring transformer for resistance butt welders comprises a plurality of sections, each composed of a non-closed magnetic core, a part of the primary winding and a part of the secondary winding. Each section is so arranged with respect to the other sections that the end faces of its non-closed magnetic core are in contact with the end faces of the two adjacent sections, whereby the non-closed magnetic cores of all the sections make up a closed magnetic core of the transformer. The primary winding of each section is connected to those of all the other sections so that they all make up the primary winding of the transformer. The secondary winding of each section is connected to those of the other sections so that they all make up the secondary winding of the transformer.

Abstract: A resistance welder is disclosed which provides the same current at the welding electrodes as comparable resistance welders while requiring less input current. The surprising efficiency of the novel resistance welder permits it to accommodate wide workpieces in a deep throat. The increased demand for power to the welding electrodes, which demand results from the deep throat, is satisfied by the surprising efficiency of the combination of elements utilized in the invention. This invention combines linear transformers, having secondary terminals at extreme linear ends of the transformers, which linear transformers function as part of at least one body member of the welder to provide unexpected efficiency. These uniquely placed linear transformers minimize throat inductance and reduce energy consumption.

Abstract: In a flash welder, instead of using a flexible conductor, the electrical connection to the moveable electrode table is made by a connecting conductor which is slidably connected both to the moveable electrode table and the secondary of the welding transformer. The connecting conductor is mounted on the moveable electrode table in such a manner that, during non-welding periods, it may be retracted within the moveable table, disconnecting it from the transformer and thereby clearing the space between the electrode tables for other workpiece machining operations.

Abstract: An electric resistance welding machine in which the welding transformer is rigidly connected to an implement holding head vertically movable on an upper bracket of the machine structure, and therefore it follows the vertical movements of the welding implement so as to reduce the electrical impedance of the circuit. A workpiece-holding table is movably mounted on a lower bracket of the machine and has a lower rib which during welding is clamped by a clamping device for providing electric contact.

Abstract: An apparatus for converting three-phase electrical energy into direct current includes Scott-connected transformers with oppositely biased SCRs connected in parallel to two of three input terminals. The SCRs are controlled so that they fire in alternate and rotating sequence between the two input terminals. The secondary output voltages of four terminals are rectified so that the common rectified output voltage is a substantially DC voltage with a minimum ripple. The secondary output terminals are aligned in a common plane and are connected to deformable, tapered leads. The rectifiers are connected between the deformable leads and to a common slotted, conductive plate which is connected to a welding electrode. A center tap from each of the secondary windings is connected to another welding electrode. The deformable tapered leads and the slotted conductive plate provide an equal resistive path for pairs of rectifiers for each secondary output to equalize the current flow through the two sets of diodes.

Abstract: The invention relates to electrical multi-spot resistance welding machine for the production of welded bar gratings produced by welding cross-bars into the narrow side of parallel, upright flat bars. Such a machine has a pressure-beam which is guided vertically on a frame for lowering onto and raising away from the bars to be welded. Two rows of electrodes are disposed on the pressure beam, the rows being transverse to the feed path of the flat bars and the electrodes in the two rows being aligned in the feed direction of the flat bars and the electrodes of each aligned pair thus formed are connected to the secondary terminals of opposite polarity of a respective welding transformer.

Abstract: The invention concerns a welding machine for electrically resistance welding together, to form a mesh, at their points of intersection in a mesh production plane, two crossed groups of parallel wires. The machine incorporates at least two pairs of opposed cooperating welding electrodes, one of said pairs being arranged on each side of the mesh production plane. A pair of transformers have their primary windings connected in series and each pair of said electrodes are connected to the secondary winding of one of the transformers in such a way that in operation the welding current will flow through the electrodes and through the secondary windings of the transformers in series.

Abstract: A rotatable shaft has a roller electrode mounted on it for rotation therewith. A transformer and a rectifier are structurally integrated to form a unit which is also mounted on the shaft for rotation with it, and serve to convert high-voltage low-amperage net current into low-voltage high-amperage DC current. Slip rings are mounted on the shaft to transmit electrical current to the unit for supply to the roller electrode.

Abstract: A control for a resistance solder unit for maintaining solder probe temperature within an acceptable range is provided using a redundant interlocking switching circuit. A pair of dual, single pole, single throw, variable time delay electronic relays, and a pair of dual, single pole, single throw electrical relays may be interconnected into the supply line for the AC to DC soldering transformer to control the time and duration of current to a resistance soldering probe. Included may be an autotransformer-coupled feedback from the resistance solder ground return of the soldering probe. Typically, visual and audible signals provide probe power status.

Abstract: An apparatus for converting three-phase electrical energy into direct current includes Scott-connected transformers with oppositely biased SCRs connected in parallel to two of three input terminals. The SCRs are controlled so that they fire in alternate and rotating sequence between the two input terminals. The secondary output voltages of four terminals are rectified so that the common rectified output voltage is a substantially DC voltage with a minimum ripple. The secondary output terminals are aligned in a common plane and are connected to deformable, tapered leads. The rectifiers are connected between the deformable leads and to a common slotted, conductive plate which is connected to a welding electrode. A center tap from each of the secondary windings is connected to another welding electrode. The deformable tapered leads and the slotted conductive plate provide an equal resistive path for pairs of rectifiers for each secondary output to equalize the current flow through the two sets of diodes.