Abstract: A weld force limiting apparatus for use in bench and press type welding units which is capable of advancing a first electrode into contact with production pieces to be welded together. The weld force limiter has a high pressure air source connected thereto for supplying high pressure air to the circuit. When an initiation switch is depressed to begin the welding sequence, provided all conditions are met, the high pressure air is ported through a regulator to regulate the pressure of the air to a very low pressure such that the first electrode advances toward the production pieces under very low pressure, in particular, at a pressure which is non-injurious to the human body.

Abstract: A spot welding machine includes tip electrodes mounted on the tips of the first and second arms, respectively, a pressing actuator for moving at least one of the first and second arms to apply a pressing force to the tip electrodes, an interelectrode distance detector for detecting a distance between the tip electrodes, and a brake for braking the actuator. The distance between the tip electrodes, i.e., interelectrode distance can be set at any desired intermediate distance between the maximum and minimum distances, by braking the actuator when the arms are opened to a desired degree. In this manner, it is made possible to effectively reduce the required operation time, and by suitably performing such a brake control, it is also made possible to effectively lessen an impact caused when the tip electrodes come into contact with plates to be welded. A speed control device may be provided which variably controls the moving speed of the actuator in accordance with the interelectrode distance.

Abstract: A shut off check valve for controlling cooling fluid flow to weld tips of a resistance welding gun. The valve is disposed within the weld gun housing and selectively interrupts cooling fluid flow between fluid inlet and outlet ports.

Abstract: A flow control system which is capable of selectively operating at least one pneumatic cylinder between high and low pressures. The flow control system allows the cylinder to engage a workpiece while under the influence of the lower pressure so as to minimize the impact on the workpiece, and thereafter subjects the cylinder to the higher pressure so as to increase the clamping load on the workpiece. Flow control is achieved by controlling the flow of high pressure air from a suitable source with a pilot-operated five ported four-way two-position control valve, a pressure regulator and a unidirectional flow control valve having an adjustable orifice. The pressure regulator is connected to one outlet port of the control valve such that the cylinder is initially supplied with air at the lower pressure when the control valve is in its normal operating position.

Abstract: The welding operation performed by the clamp 12 is under the control of a welding cabinet 15 including a servo-control unit 16' and an electronic switch 17. The clamp is moved from one weld spot to another by a robot 13 under the control of a control unit 14 provided with a servo-control unit 16. The switch 17 is controlled in such a manner that the welding operation and the beginning of the clamp opening operation and the end of the clamp closing operation are under the control of the welding cabinet 15 (with the robot then remaining stationary), while displacement of the clamp synchronizing with wide opening and closing thereof are under the control of the control unit 14.

Abstract: A method and apparatus for diagnosing various faults during resistance welding based upon electrode position. An electrode positioning bracket is coupled to the electrode. The position of the bracket is measured by means of a linear variable displacement transducer. The position of the bracket is used to determine the electrode position, and in turn, electrode positioning faults, and weld quality.

Abstract: A resistance welding gun which is adapted to prevent asymmetrical impacting of two or more metal sheets to be welded. The resistance welding gun includes a pair of rotatably connected arms, each of which has a corresponding working end and actuation end. An electrode tip is located at each working end to provide a pair of opposed welding electrodes, while a cylinder is attached to the actuation ends of the arms to provide rotation therebetween. Between the actuation ends there is provided an equalizing mechanism including a crank and a pair of linkages which serve to equalize the movement of the arms about their pivot. In cooperation with the pivot of the arms, the crank establishes a fixed or datum point at which the electrode tips of the resistance welding gun are targeted such that, when properly positioned on opposite sides of the metal sheets, the electrode tips contact the metal sheets substantially simultaneously and apply substantially equal forces to the opposite sides of the metal sheets.

Abstract: The present invention provides a weld control monitoring system which determines the quality of the welds in real time, and provides responsive useful outputs indicating the quality of the weld. The system permits the user to input weld data as well as quality specifications which the part must meet in order to continue the production run. A monitoring system can be used with or without programmable logic controllers and includes special program for estimating the tip wear of the welding electrodes. The present invention also includes a weld gun control in which additional support for the weld gun electrode is provided by adjacent rail structures which permit displacable movement of the electrode mounted to linear displacement welding cylinder. A sensor coupled to the piston rod of the weld cylinder provides linearly variable displacement transducer signals for use in monitoring portion of the apparatus.

Abstract: A stopper device in a welding robot gun is capable of increasing the amount of movement of the upper arm and reducing the amount of movement of the lower arm or vice versa by adjusting the protruding amount of the stopper bolt from the rear wall of the stopper cylinder inside the stopper cylinder and of preventing the upper and lower arms from moving unstably from the state where the welding gun is open to the state where a pressure cylinder supplies fluid under pressure. The stopper device comprises a cradle, a stopper cylinder having a rod fixed to the cradle, a tip end of the rod connected to a rear end of the upper arm by way of a link wherein the stopper cylinder has a front chamber provided with a fluid supply and discharge port and a rear wall into which an adjustable stopper bolt is screwed so as to protrude deep or slight therefrom inside the stopper cylinder.

Abstract: An apparatus for applying a force to a workpiece as required in welding or clamping. The apparatus applies a force to the workpiece through a direct clamping action or through link enhanced scissor type action that increases the mechanical force supplied by a fluid driven cylinder. The fluid driven cylinder has piston rods at both ends of an elongated external housing. The fluid driven cylinder is supported at one end by an attachment to the end of one piston rod and is supported at the other end by an attachment to the external housing. A plurality of pistons permit the piston rods to move relative to one another and also relative to the external housing. The entire fluid driven cylinder can rotate and translate.

Abstract: A C-type welding robot gun holding apparatus having a pressure cylinder which is short in the longitudinal direction thereof and a welding robot gun which is low in height. The C-type welding robot gun holding apparatus comprises an L-shaped bracket fixed to a tip end of a robot wrist and having a projection, a fixing cylinder disposed over the pressure cylinder having a rod which is disposed in confronting relation with a front surface of the projection at a tip end of the rod and a stopper provided at a stopper holding member protruding from the rear end of the pressure cylinder being directed toward a rear surface of the projection.

Abstract: An articulated pair of spot welding tongs comprising two supports (1,2) of the male and female type, each having a fork joint and an orifice, and two interchangeable arms (3,5), each carried by one of the supports. Each support is made from aluminum and treated by hard anodizing. A pin (13) traverses the two orifices, and carries two plates (39,40), each plate comprising a metal support plate covered by a coating based on fluorocarbonated fibers. The welding tongs can be used for a long period of time without any need for changing the insulating elements.

Abstract: A method and apparatus for single-sided resistance spot welding that prevents excessive weld indentation. A first flat part and a tubular part are clamped between welding electrodes with a predetermined welding force. A welding current is applied to the electrodes to heat the parts where the spot weld is made. One of the electrodes is locked from movement as welding current is applied to prevent that electrode from indenting into the heated weld zone.

Abstract: Pressure applying device for resistance welding which includes a pair of two gun arms having an electrode tip at two opposed ends of the arms, a flexible supporting means connecting said two arms, an actuator provided between said two arms, and a link mechanism connecting said two arms to define movement of the electrode tip. According to this invention, the operation of said actuator to pull the gun arm allows the electrode tips in the open position as well as the supporting means accumulating resilience. And, the reverse operation of said actuator can provide an elastic force by said flexible supporting means acting on the pieces between the electrodes, in addition to the welding pressure by the actuator.

Abstract: An apparatus for passing an electrical current through an electromagnetic coil to perform a resistance bonding operation is disclosed. The apparatus includes a pair of pistons which are selectively moved to clamp the leads of the coil to respective electrical terminals. The terminals are selectively connected through a switch to a source of electrical power to perform the resistance bonding operation. A pivotable cover is provided for covering the entire apparatus during the resistance bonding operation. When the cover is closed by an operator, a logic controller automatically actuates the pistons to clamp the leads of the coil to the terminals. Additional limit switches sense when the pistons have been so moved and, in response thereto, automatically close the switch to connect the electrical power supply to the terminals, thereby commencing the resistance bonding operation.

Abstract: A welding gun provided with a backup cylinder is characterized in that the welding gun is moved toward a workpiece by a welding robot an end of which is connected to the welding gun via a bracket, then one electrode is brought into contact with the workpiece by a backup cylinder so that the workpiece is held by one electrode, thereafter the other electrode is brought into contact with the workpiece by a pressure application cylinder so that the pressure force is applied to the workpiece by both the electrodes for welding operation.

Abstract: A welding gun comprises a base having a stopper at the tip end thereof and a vertical axis at the inside thereof, an arm having an electrode at the upper end thereof and a lower end slidably engaged with the vertical axis, cylinder integrated with the arm 1 and having a cylinder rod, a movable arm having an electrode at the tip end thereof and pivotally connected to the tip end of the cylinder rod at the rear end thereof by a pin, a link for pivotally connecting the arm with the movable arm at the middle portions thereof by pins, the link having an engaging portion at the lower end thereof extending toward the stopper and a spring provided in a space between the lower end of the vertical axis and the lower end of the arm. The arm, as opposing the movable arm, can be equalized with ease.

Abstract: A multi-purpose control system for a backup type welding gun and similar apparatuses including a positioning directional control valve for controlling the extension and retraction of the positioning or backup cylinder. A multi-pressure air sequence circuit and a time delay means operatively connected to the air sequence circuit for controlling the admission of a predetermined low pressure into the retract port of a backup type welding gun positioning cylinder to speed up the extension movement of the position piston carrying a weld cylinder, and then to control the admission of a predetermined higher retraction pressure higher retraction into said retract port, after a predetermined time delay interval.

Abstract: There is disclosed a C-type welding gun provided with an air cylinder, an equalizer disposed over the air cylinder, a yoke disposed aside the air cylinder and the equalizing unit, a welding transformer disposed over the equalizer. Each of the air cylinder, the equalizer, the welding transformer, the yoke is a separate unit and the resultant each unit is replaced individually with other units with ease.

Abstract: A retracting rocker unit comprises a base 10 mounting a linkage 12 and a power unit 14 which cooperates with the linkage to move a welding electrode of clamping jaw from the position shown initially vertically and then to the right.

Abstract: A force limiting weld head (11) which includes a supporting structure (13), a pressure barrel (15) and an output member (17) mounted for movement on the supporting structure, a fixed electrode (19) mounted on the supporting structure, a movable electrode (21) driven by the output member, a coupling (23) for drivingly coupling the pressure barrel and the output member. The coupling includes a variable-volume chamber (89) and a piston (77) responsive to overtravel for varying the volume of the chamber.

Abstract: Each electrode rod unit is composed by inserting into a cylindrical block an electrode rod which is linked to the cylindrical block through a conductive cable. The electrode rod unit is removable fastened onto an electrode plate and pipings for both cooling and pushing out each electrode rod and a fluid pressure piping for its retraction are joined to the electrode unit.

Abstract: A welding gun comprises a fixed arm having an electrode at an end thereof and integrated with a cylinder at the other end thereof and a pin at the middle portion of the fixed arm for swingably mounting the fixed arm on a base, the cylinder having a piston provided with a rod at the distal end thereof; a movable arm having an electrode at an end thereof opposite to the electrode of the fixed arm, a pin at the other end thereof for connecting the movable arm to the rod of the piston, and a pin at the middle portion of the movable arm; and a link connecting the pins respectively provided at the middle portions of the fixed arm and the mocable arm for pivotally connecting the fixed arm to the movable arm.

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: A system for assembling a vehicle body has a panel handling device provided with a panel holding tool for holding a body panel and a first welding gun for welding the body panel to a vehicle body. A robot has a connecting mechanism to which the panel handling device or a second welding gun is selectively connected. A panel setting mechanism which is provided with a support portion for supporting the panel handling device delivered by the robot locates the panel handling device so that the body panel on the panel handling device is correctly positioned for incorporation into the vehicle body. The second welding gun is connected to a power source, and said panel handling means is provided with a power receiving portion by way of which the first welding gun receives power supplied by the second welding gun which is held by the robot.

Abstract: A weld gun assembly including a support structure; a pair of arm members pivotally mounted intermediate their ends on the support structure on a common pivot axis; a weld tip at one end of each arm member; an air cylinder interconnected between the other ends of the arm members and operative when actuated to move the weld tips together in a closing direction; and a pair of hydraulic cushioning devices extending respectively between the support structure and one arm member and between the support structure and the other arm member. The cushioning devices are selectively adjustable to vary the resistance provided to the movement of each arm member toward its closed position so that the resistance to the closing movement of each arm member may be selectively adjusted in compensation for the unbalanced forces that are acting on the individual arm members and thereby ensure that the weld tips arrive at their welding position adjacent the panels to be welded at the same time.

Abstract: A hydraulic system for use in a resistance welding machine with a stationary electrode and a variable electrode to provide adjustment of the stationary electrode to ensure proper positioning to maintain weld quality. The hydraulic system comprising an actuated piston attached to the stationary electrode, a motive piston to control the flow of hydraulic fluid in the hydraulic system, a hydraulic locking device to lock the stationary electrode in a stationary position to resist forces during the welding operation and a pneumatic control system to operate the hydraulic system.

Abstract: A weld gun assembly including a support structure; a pair of arm members pivotally mounted intermediate their ends on the support structure on a common pivot axis; a weld tip at one end of each arm members; an air cylinder interconnected between the other ends of the arm members and operative when actuated to move the weld tips together in a closing direction; and a pair of hydraulic control devices extending respectively between the support structure and one arm member and between the support structure and the other arm member. The control devices function to ensure that the weld tips arrive at their closed welding position adjacent the panels to be welded at the same time irrespective of unbalancing forces acting on the weld gun and further function to ensure that there are no unbalancing forces tending to move the closed tips away from their closed positions.

Abstract: Welding tongs for dot or spot welding having two arms which are disposed without crossing relationship and carrying weld electrodes respectively on one end. The arms are made of flat, spaced bars, and a substantially flat spacing member made of an elastic or resilient material, spaces the two arms from each other thereby interconnecting the tong arms in a range of pivot motion of the arms. An E-shaped mounting member limits lateral deflection of the tong arms and holds the spacing member. A hydraulic drive is connected to the other ends of the tong arms for obtaining the pivot motion of the arms in relation to each other, through tensioning and upsetting or compression of the spacing member.

Abstract: A welding machine controller for controlling the welding operation of a welding machine controls welding force applied to a workpiece by directly controlling a pressure regulating valve which regulates the pressure of working fluid supplied to a power cylinder for applying a welding force to the workpiece. The welding machine controller further controls squeeze time, welding time, hold time, OFF time, cooling time and welding current. The welding force is regulated in a single step or in a plurality of steps during one welding cycle according to the quality and/or thickness of the workpiece.

Abstract: A welding gun apparatus for resistance welding including a longitudinal guide track provided on a pair of fixed plates. The longitudinal guide track extends in a substantially vertical direction and is engaged with both the lower end portion of a carriage for holding a movable electrode arm having a movable electrode and the upper end portion of a piston rod by pins. An arciform guide track formed in the carriage is engaged with pins secured to the respective fixed plates. The longitudinal guide track and the arciform guide track forces the movable electrode arm to move upwardly in a substantially vertical direction at a first stage and then upwardly and obliquely when a workpiece is fed from, and a new workpiece is fed into, a welding station. The carriage is moved smoothly between the welding station and a retracted station, and a sliding portion is prevented from being worn.

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: A pressure regulator control system for controlling the pressure with which welding electrodes are engaged against a workpiece comprises a transducer for establishing a first regulated fluid outlet pressure proportional to the strength of an electrical signal delivered to the transducer, and a pressure regulator or booster relay for establishing a second regulated outlet fluid pressure which is a multiple of said first outlet pressure. The outlet of the pressure regulator or booster relay is then applied to the working cylinder controlling displacement of the electrodes. The control system of the preferred embodiment includes interface means for converting digital data received from a computerized control apparatus to an analog signal which is applied to the transducer.

Abstract: Connecting metal fittings for resistance welder comprise receiver metal fittings connected to transformer side and clamping metal fittings connected to a resistance welding gun side. The receiver metal fittings include terminal strips and power supply connecting plates, both provided on the transformer side and fixed thereon, and a pair of rotatable clamping handles having stopping cylinders and stopping pins both provided on a handle lever. The second metal fittings include a shaft lever penetrating the terminal strips on the welding gun side and being inserted into notched grooves formed in tips of the power supply connecting plates, spring sockets being slidably inserted into both ends of the shaft lever, plate springs disposed between the spring sockets and power supply connecting plates, and a cam having stopping levers composed of stopping hooks formed on the tips thereof, and fixed thereon and adapted to make contact with the spring sockets.

Abstract: A method and apparatus for assembling three-dimensional wire structures. The method includes the steps of preparing a series of plane nettings comprising lengthwise wires and brace wires, and aligning the nettings on holders. The method further includes the steps of placing a pair of cross wires across and against the lengthwise wires of the nettings and welding the cross wires to the nettings. These last two steps are repeated, each time with the nettings in a different position, until the three-dimensional structure is completed.

Abstract: An improved machine with automatic finger safety guard includes a machine body having a finger-accessible work space and at least one movable machine component disposed in the work space. An electric motor is connected by leads to a power source and is also connected to the movable component for powering the component. An automatic finger safety guard is installed on the machine and preferably includes a hollow tube disposed around the work space and movable between an operative protective position and an inoperative retracted position. Switches are connected to the enclosure and to the electric motor leads for automatically interrupting the powering of said movable component upon movement of the enclosure from the fully protective position to the retracted position. The machine preferably includes a resistance welding machine having a pair of welding electrodes which approach each other in the work space, at least one of which electrodes is movable into and out of the work space.

Abstract: A resistance welding electrode for producing spot welds on a workpiece without marring comprises a hollow electrically conductive shank for conducting welding current and pressurized cooling fluid, an electrode head affixed to a rigid, electrically insulating, tubular housing having a flange with a groove and surrounding the free end of the shank, a spring engaging the shank and tubular housing to bias the head out of engagement with the free end of the shank and a ring of resilient, fluid sealing material retained in the groove to engage the shank and form a chamber with the tubular housing and head for cooling fluid from the shank. The ring allows rocking movement of the tubular housing and head relative to the shank so that the workpiece contact area may conform to the workpiece when welding pressure is applied to the shank.

Abstract: A welding head for resistance welding, in particular for spot welding, comprising a frame to which a first welding electrode is fastened in a fixed position and a carrier for a second electrode lying substantially opposite the first electrode, said carrier being movable with respect to the frame in a manner such that the second electrode can be displaced in the direction to the first electrode, the second electrode being fastened to an element which is displaceably connected with the carrier in a manner such that it can perform a movement in a direction substantially parallel to the direction of movement of the carrier.

Abstract: An air assisted hand welding tool for clamping and welding conductors together. The tool includes a handle formed of pivotally connected lever-like members. An air passage is connected to an air pressure source provided in the handle of the hand tool. A valve is manually engaged by the operator (following tactile closing of the electrodes on the conductors) to open the air pressure to an expansion chamber formed between the members. As the chamber pressure is increased, the members are urged to a consistent clamping force thereby to assist the operators normal hand clamping function. A switch in the expansion chamber is connected to the welding circuit and is activated following chamber expansion to initiate welding. The entire welding operation including air assist and welding current initiation are all accomplished by a simple closing motion of the operators hand.

Abstract: The present invention is directed to a gun arm for a resistance welding gun. The gun arm comprises a main body, an electrode holder mounted on the front portion of the main body and a support member fixed to the rear portion of the main body. The main body comprises a conductor member having a water passage on at least one side thereof and a plate member fixed to at least one side of the conductor member and in contact with the water passage. In one embodiment of the present invention, the water passage comprises at least one groove formed in the conductor member with the groove being covered by the plate member. In an alternative embodiment, the water passage comprises at least one pipe which is positioned between the plate members which comprise the at least one plate member.

Abstract: A compact apparatus for applying equal force to opposite sides of a workpiece including an arm mounted on a frame for movement in a plane to be rotated into alignment with the workpiece. The arm is moveably connected to the frame and is guided into position to engage the workpiece by tracks and followers. The workpiece is engaged on opposite sides by a tool and an anvil which perform an operation thereon. The forces applied by the tool and the anvil are equalized by a pivotable member to prevent distortion of the workpiece while performing the operation. The pivotable member engages a biasing spring which is connected to the frame on its lower end and engages the arm on its upper end to urge the arm in one direction relative to the frame.

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: A method and apparatus are disclosed for detecting weld nugget growth on a workpiece during a welding operation using a resistance spot welding gun. In the preferred embodiment, a piston rod is slidably mounted in a cylinder and is connected at one end to an electrode of the gun. The opposite end of the piston rod extends rearwardly through the cylinder and is coupled to a sensor assembly for detecting the amount of movement of the piston rod created by weld nugget growth on the workpiece during the welding cycle.

Abstract: A spot welding gun adapted for use in robotic welding in which the electrode holding arms of the gun are each turnably journalled on an attachment means. One of the electrode holding arms or an operating lever thereof supports a cam member with a cam surface thereon. A pressure roller acts against said cam surface during transport of the welding gun between welding points and thereby holds each electrode holding arm in a respective fixed position relative to the attachment means.

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 scissors-type electric welding apparatus is provided which has a transformer, a pair of electrodes, a pair of first arms movably mounted on the transformer, an electrically insulated articulation shaft, and a pneumatic jack. A pair of second arms are pivotably connected to the articulation shaft. The second arms support the electrodes on one end and are connected to the jack on the other end in order to move the electrodes apart to position the electrodes for welding workpieces. The electrodes are electrically connected to the first arms through the second arms. Each second arm includes a contact member mounted on the articulation shaft. Each first arm includes a free end which carries a contact shoe for interacting with a contact member. A biasing member is provided for urging the contact shoes against the contact members.

Abstract: Resistance welding apparatus with a compound electrode holder is provided. The apparatus is more effective in resistance welding members of U-shaped cross section than apparatus heretofore known. The compound electrode holder enables its electrode to travel in one arcuate path throughout most of its travel or stroke and to move in a second arcuate path as it approaches the workpiece. The compound electrode holder achieves a large path of travel of its electrode and at the same time accurate alignment of the electrodes and reliable welds are attained.

Abstract: A modular welding apparatus comprises a welding head assembly having a welding head with an integral actuating assembly. A foot treadle initiates motion of the welding head. A conductive base member is spaced from the welding head. A welding power supply has one lead connected to the welding head and a second lead connected to the base member. An interchangeable welding module is disposed on the base member in electrical contact therewith. The welding module includes a conductive support plate and a locking cam for detachably attaching the support plate to the base member. A welding mandrel comprising one welding electrode is in contact with the support plate. An insulating member is attached to the support plate and an articulated welding electrode assembly is attached to the insulating member.

Abstract: A Robot type resistance welder of very large capacity that enables the electrodes of the welder to be readily adjustable in the welding and retracting strokes and automatically controlled so as to retract when encountering an obstacle - also whereby the degree of retraction of electrodes may be selectively controlled and whereby the vertical elevation of the work plane may be varied during welding in accordance with the contour of the work, such as a curved panel. The respective electrodes of the spot welders have supporting arms which are pivotally interconnected together with an operating air cylinder. An adjustable stop is provided in the air cylinder to adjust the extent of retraction. The entire assembly including the pivotal supporting arms and inter-connected cylinder are provided with an adjustable stop for limiting the pivotal movement of the assembly. Such pivotal movement is cushioned by springs.

Abstract: The disclosure relates to the production by means of an electrical resistance welding method, of grids formed from metal wires crossing over another. The grid wires are carried through between rows of cooperating electrodes and, under pressure, are welded together at the cross points of the wires by an electric current. Each cross point of the wires and the surfaces of the associated electrodes of the grid welding machine, which lie in the welding region, are subjected to the action of a liquid coolant to increase the life of the electrodes and reduce distortion of the grid due to the localized heating of the wires.