Abstract: An orbital welder includes a weld tip, a rotational controller, and a translational controller. The rotational controller causes the weld tip to rotate about an axis passing through the tube to be welded. As the weld tip rotates about the axis, the translational controller causes the weld tip to move longitudinally with respect to the axis, forming non-planar orbital welds. In one embodiment, the translational controller includes a rotor disposed to rotate about the axis. The translational controller further includes a carrier that is slidably attached to the rotor, and the weld tip is fixed to the carrier. As the rotor rotates about the axis, the carrier moves longitudinally with respect to the axis, such that the weld tip follows a non-planar orbital weld pattern. In a particular embodiment, a portion of the carrier is biased against a surface a cam block.

Abstract: Applicant's invention includes an apparatus and associated method for precisely aligning two pieces of weldable material and welding the two pieces, the apparatus contains means for independently securing the two pieces of weldable material and for centering the junction of the two pieces in line with the welding electrodes.

Abstract: The present invention relates generally to an apparatus and method for performing tube-to-tubesheet welding within box headers and, in more particular, to a GTAW welding gun that has a long generally tubular barrel which is small enough in diameter to pass through the plug holes on one side of a box header and long enough to reach over to the point of connection on the opposite tubesheet. Additionally, and as a critical part of the instant invention, the torch is fitted with a semi-automatic cold wire feeding apparatus and an associated wire feed liner that is constrained to be proximate to the exterior of that tube throughout said barrel's length. Thus, both the barrel of the welding torch and its accompanying wire feed liner are sized to fit within and pass through a plug hole.

Abstract: A gas shield strip cladding welding system including a workpiece, a strip of welding material, an enclosure having an opening through which the strip of welding material passes, a feeder for controllably passing the strip of welding material into the enclosure through the opening, a gas delivery conduit connected to the enclosure so as to pass a shielding gas into the enclosure adjacent to the strip of material, and a power supply electrically connected to the strip of welding material and to the workpiece such that an arc is produced when the strip of welding material comes into close proximity to the workpiece. A mechanism is connected to the enclosure so as to move the enclosure continuously relative to the workpiece so as to deposit the welding material in a desired pattern. The shield gas includes an inert gas.

Abstract: Plasma arc cutter apparatus for cutting large diameter pipe from within the pipe, a frame with adjustable legs, a locking device to secure the apparatus within the pipe, apparatus to adjust the spacing between the plasma arc and the inside wall of the pipe during cutting, a drive shaft to rotate the cutter apparatus around the circumference of the pipe during cutting, controls to change the elevation of the drive shaft to vary the angle of cut, and adjustment devices to center the drive shaft within the pipe.

Abstract: A system of machined and welded pipe with no connectors or scarfed welds and method to provide a continuous section for pipe and pipe-like structures; displaying electron beam welding for constructing continuous pipe.

Abstract: A system of the invention for supervising piping work comprises a machine for performing piping work such as welding of pipes or tightening of pipe joints under predetermined conditions, check means for checking whether the piping work has been executed properly based on predetermined values of piping work conditions and actual piping work data, a host computer for accumulating the predetermined values of piping work conditions, the actual piping work data and the result of checking, and communication means for transmitting the predetermined values of piping work conditions, the actual piping work data and the result of checking.

Abstract: An improved plasma arc welding arm method and apparatus for keyhole welding rotating workpieces has an arcuate gear track supporting a corresponding arcuate geared cart bearing a plasma arc welding torch prevents voids in keyhole weld starts and finishes. The gear track is mounted on a manipulator arm for positioning the welding torch in proximity to a rotating workpiece to be welded. The torch may be rotated on the cart and gear track in the same direction and at the same rotational speed as the workpiece.

Abstract: An orbital welding apparatus (B) comprises a modular weld head apparatus (10) including a rotor assembly (20) which carries a welding electrode (26). The rotor assembly is rotated about an axis for welding abutting ends of tubular members positioned in alignment on the axis. The rotor assembly includes a C-shaped insulating rotor member (22) which has teeth (28) disposed around an outside periphery thereof. The insulating rotor member is configured to receive an electrically conductive member (24). The conductive member is insulated by the rotor member to reduce arcing from the conductive member to other components. A drive assembly (98) within the weld head assembly engages the insulating rotor member to rotate the rotor assembly about the axis during welding.

Abstract: The subject invention is a tube welding apparatus for the welding of small tubes, such as those one-sixteenth of an inch to one-half inch in diameter. The tube welding apparatus includes a drive housing to which is supplied inert gas, cooling water and electricity. Different torch housings are to be mountable in a removably disengaged manner on the drive housing with only a single torch housing being mounted to the drive housing at any given time. The torch housing includes a rotor gear within which is mounted the welding electrode with this rotor gear to be rotatably driven about the tube that is to be welded. Also mounted within the torch housing is an electrical brush which is to be in engagement with the rotor gear with the brush also including electrical connecting plugs which are to engage in a mating manner with sockets formed on the drive housing on which mounts the torch housing on the drive housing.

Abstract: An improvement to orbital welding heads and welding systems for welding pipe and tubing butt joints, consisting of a removable or retractable detector module in the welding head for sensing the proper alignment of the welding head to the pipe joint prior to welding. The module contains a light source that shires a light beam on the pipe wall, and a detector with associated circuitry and output indicators to signal when the reflected light is interrupted by the presence of a seam or pipe joint. The module may be in the form of a battery powered module that with the use of sleeves fits into the viewing port of a variety of welding heads, or it may be an integral capability that retracts into the side of the weld head out of the way of the welding tip orbiting mechanism.

Abstract: In a plasma welding process, a voltage is applied between an electrode and an object for welding with injecting a plasma gas to generate a plasma, and welding is performed with taking the plasma as a heat source. The process cyclically varies energy contained in a plasma arc by cyclically varying a plasma gas flow rate.

Abstract: An orbital weldhead having minimum thickness incorporates integral cooling and includes a nonconductive housing having a circular aperture for insertion and removal of the workpiece. A nonconductive self-lubricating race is mounted in the housing and surrounds the aperture, and an integral cover adapted to mate with the housing incorporates a nonconductive outer body and an electrode plate secured to the body adjacent the nonconductive race. The electrode plate includes a machined coolant flow channel engaging the nonconductive body of the cover to form a coolant flow channel surrounding the aperture.

Abstract: A plasma arc pipe cutting apparatus incorporates a plasma arc torch adjustably coupled to a motor-driven ring which transports the torch in an orbit about the pipe to be cut. The apparatus includes a pipe clamping fixture allowing the pipe to be cut to be concentrically mounted within the ring so that the gap between the electrode of the plasma arc torch and the work piece remains constant through the orbital travel of the torch.

Abstract: Applicant's invention includes an apparatus and associated method for precisely aligning two pieces of weldable material and tack welding the two pieces together. The apparatus contains means for independently securing the two pieces of weldable material and for centering the junction of the two pieces in line with the tack welding electrodes.

Abstract: A workholder to hold a workpiece, especially an end fitting, in accurate axial and angular orientation for orbital welding. It can optionally provide protection for sensitive surfaces on a fitting during the welding and handling processes.

Abstract: A system (and method) of controlling and simultaneously displaying arc welding torch parameters includes a power supply for supplying weld voltage and current to the torch in accordance with demand signals from a computer. The computer also supplies a demand motor speed to a motor for controlling the travel speed of the torch electrode relative to a workpiece or the fed rate of a filler wire to the weld area. The actual values of the weld voltage/current and the motor speed are fed back to the computer and displayed on a video color display in separate colors and in real time to enable on operator to readily correlate the actual with the demand parameter values. The position of the electrode relative to the workpiece is also fed back to the computer for presentation on the video display. In addition, deviations of the individual actual parameter values from acceptable tolerance limits are highlighted on the display.

Abstract: An orbital welding head for joining two tubes positioned end-to-end includes a welding electrode which is rotated around the tubes and a pair of clamps for holding the tubes in the correct position with respect to each other and the welding electrode. The clamps include a fixed member, a rotatable member and a hinge assembly for joining the rotatable member to the fixed member. The rotatable clamp members are moved clear of the tubes when the tubes are either inserted into or removed from the welding head. Fluid channels are formed in both the fixed and rotatable clamp members. The hinge assembly connects the rotatable clamp member with the fixed member. Fluid channels within the hinge assembly allows cooling fluid introduced into the fixed member to be carried through that member into the rotatable member, cooling both. A return fluid channel is also provided by the hinge. The hinge is provided with a passageway for transferring cooling fluid from one rotatable clamp member to another.

Abstract: An orbital welding apparatus includes a first housing defining a weld head assembly and a circular rotor disposed therein for rotation about a first axis. A welding electrode is carried by the rotor for welding. A second housing separate from the first housing forms a power transmission and has a second drive shaft extending therefrom. A flexible drive shaft connects the first drive shaft and the second drive shaft to conduct rotary drive forces from the first drive shaft to the second drive shaft while permitting the relative orientations of the first and second housings to be freely adjustable. A third and independent housing carries an electric drive motor and forms a power drive motor module with a rotary output shaft. A releasable clamping mechanism is provided for positioning and holding cylindrical members to be welded in an axially aligned relationship with their ends abutting in a single plane.

Abstract: A water cooled orbital welding apparatus permits continuous welding of pipes and tubes in a limited space by including a liquid cooled plate inside a head assembly to remove heat from the gear carrying the welding electrode around the tubes being welded. A plurality of spring loaded ball bearings maintain the rotating gear in tight contact with the cooling plate. By keeping the gear and electrode cool, thermal expansion of the internal components of the welding head is minimized. Since thermal expansion is not a major factor, noncompatible materials in terms of thermal expansion characteristics may be used in the construction of the device. A removable cassette of symmetrical design allows a cassette to be mounted on the head from either the right or from the left, thus allowing the operator to open the clamps on the cassette from either the front side or the back side of the weld head. An offset hinge on the cassette permits the cassette to be removed from the welded tubes in confined space.

Abstract: An orbital welder for welding tubes includes a welding head and a hinged clamp arrangement which grasps the tubes and holds them in abutment for welding. The clamp is constructed to discharge shielding gas into the welding region. By supplying gas only from the clamp, a high purity weld is achieved.

Abstract: To ensure the sealed fixing of a replacement heating rod (4) on a collar (3) for passing through the casing (1) of a pressurizer, a weld is made in a single pass by a regulated MIG process. A shaft is fixed on one end of the heating rod projecting in relation to the collar (3) and in the extension thereof. A welding device is engaged and fixed in position on the shaft, this welding device comprising a tubular support (14) and an inert-gas orbital welding torch (10) with an electrode made of fusible metal, rotatably mounted about the axis of the support (14) which coincides with the axis of the rod (4). The welding torch (10) and a device to unwind welding wire which is placed in a cabinet (6) are set into synchronous rotation during the welding, by appropriate drive means. The welding is carried out in a single pass on the entire periphery of the heating rod (4) and of the collar (3).

Abstract: An orbital welding apparatus comprising a modular weld head unit including a circular rotor carrying a welding electrode for rotation about an axis for welding abutting ends of tubular members positioned in alignment on the axis. A drive assembly for driving the rotor includes a motor unit carried in a separate modular housing for ready manual connection and disconnection from the weld head unit. In the preferred form a transmission module is connected with the motor unit and connects to the weld head unit by a flexible drive shaft assembly to allow the motor unit to have substantially any desired orientation relative to the weld head unit. There is also disclosed a separate clamping assembly for holding the tubular members relative to the weld head unit.

Abstract: A clamp intended for the end-to-end welding of two tubes disposed in accordance with an axis (3) by an electrode (14) operating in a circular movement (18) includes two collars (1, 2), mounted pivotably around the axis (3), put into rotation by gears (7, 8, 10, 11). On one collar (1) a swinging element (13) is pivotably mounted and used to support the welding electrode (14). A cam (16) is provided on the other collar (2), which cooperates with an integral element (15) of the swinging element (13). The two collars are put in motion by two distinct motors which are connected with regulation and control devices which permit a change of the rotation speed of at least one of the collars in such a way that the distance between the electrode (14) and the axis (3) is changed. In this way the height of the arc is controlled.

Abstract: Arc welding apparatus and method for precisely welding abutting pipe end portions defining an interface having a seam or joint to welded. The apparatus includes a roller assembly for precisely rolling the apparatus around a track circumscribing one of the pipe portions so that the seam may be suitably welded. Connected to the roller assembly is a carriage which carries an electrode housing having an electrode housed therein. A gear rack is provided on the roller assembly for engaging a pinion gear on the carriage for precisely biasing the carriage and thus the electrode housing parallel to the longitudinal center axis of the pipe portions. Connected to the carriage is a lead screw assembly for precisely biasing the electrode housing and thus the electrode perpendicularly to the longitudinal center axis of the pipe portions to be welded. Connected to the electrode housing is a manipulator arm for precisely manipulating filler wire at the weld site.

Abstract: In a boiling water nuclear reactor having its core, fuel support casting, and control rod guide tubes removed to expose the core plate, an apparatus and method for the submerged welding repair and replacement of the control rod drive housing at the bottom extremity of the reactor vessel is disclosed. The apparatus registers to a hole in the core plate and its corresponding guide pin. A mating fixture on the depending extremity of the shaft of the apparatus precisely fits and mates to the top of the control rod drive housing. The alignment device includes cross electronic levels sealed for submersion which levels remotely transfer through attached wiring the precise angularity between the top of the control rod drive housing on one hand and the corresponding and overlying hole in the core plate on the other hand. For the welding repair process herein, a welding cylinder apparatus fits over the depending end of the shaft of the alignment device.

Abstract: A welding apparatus (10) for longitudinally traversing and circumferentially welding within the interior of a tube. A rotating weld tip and gas supplying containing head is mounted on and rotationally driven by a rotor tube (36) extending from the end (90) of a cylindrical housing (12) in which it is mounted. The axially fixed rotor (36) is surrounded by and is driven by a helix drive connection (52,54,56) to a piston (20). The piston (20) reciprocates in a cylindrical bore (14) within the housing (12) in response to selectively applied fluid pressure acting against a spring bias (26). A strain gage (72) on the spring (26) controls the fluid pressure by means of valve ("V") whereby reciprocation of the piston (20) rotates the rotor (36) by means of the helical groove (52) and balls (54). The various parts are hollow to accommodate the necessary wire conductors (70,86) and gas flow.

Abstract: A thick tube welder for welder together a tubular end fitting and a tube. The end fitting and the tube are placed in axial alignment within a welding head housing with the end fitting being located in a mounting housing. The mounting housing is then fixedly secured to the welding head housing. An inner welding electrode is connected to the mounting housing and is located in alignment with the inner surface of the welding joint. An outer welding electrode is located in alignment with the exterior surface of the welding joint with this electrode being mounted on the welding head housing. Both electrodes are rotatably driven either simultaneously or in sequence in order to create the weld between the tube and the end fitting. Depending on the length of the end fitting, the inner welding electrode is to be adjustable longitudinally relative to the welding joint.

Abstract: A plasma welding method has successive steps including pre-heating of members to be welded, tack welding of the members for tentatively fixing these members, keyhole welding for completely welding the members to each other, and finish padding. These steps are automatically conducted by a single plasma welding apparatus operative in accordance with a programmed sequence including data concerning the optimum conditions of operation in each step in relation to the conditions such as sizes and materials of the members to be welded.

Abstract: A pipe welding apparatus which utilizes a pair of welding electrodes which are at least ninety degrees spaced apart relative to a cylindrical workpiece. The welding procedure only occurs during movement of each welding electrode from an upper position to a lower position.

Abstract: A device for radial machining and welding of a tubular body, said device comprising a tool support which can be placed around the tubular body and including four rollers assuring its guiding in rotation. The support comprises a main body of relatively massive shape which can receive, in its central part, a machining tool or welding tool, and to which are fastened two guide rollers. The guide rollers are placed on both sides of the axis of symmetry of the tool support. Two guide carriages are provided, on each of which guide carriage is mounted a guide roller, and means are provided to modify the position of the guide carriages in relation to the body as a function of the diameter of the tubular body.

Abstract: A clamping device for holding cylindrical workpieces having a nominal radius R which varies from a minimum of (R-A) to a maximum of (R+B), where A and B are the limits of the tolerance range for the nominal radius. The clamping device includes opposed clamp halves each having a clamp face adapted to be moved toward and away from one another and each of the clamp halves carrying a rigid collet element adapted to engage on opposite sides of cylindrical workpieces when the clamp halves are moved toward one another. According to the disclosure, each of the collet elements has a semi-cylindrical clamping surface extending inwardly from the clamp face of the respective clamp half. Each semi-cylindrical clamping surface has a radius substantially equal to R+B) with the center of the radius being offset outwardly of the clamp face of the respective clamp half an amount at least equal to (A+B).

Abstract: Internal welding head apparatus, wherein a welding torch is mounted on a pivotal support for movement of the torch toward and away from the weld site, and wherein the torch is carried on a rotative shaft to be oscillated transversely by oscillation of the rotative shaft, oscillation of the rotative shaft being accomplished by rotation of an eccentric in a yoke fixed to the rotative shaft, and wherein the oscillations are dampened by spring means disposed at opposite sides of the rotative shaft. The apparatus is compact, and is adapted to be mounted on a carrier to be rotated about the interior of a pipe or tank, or the like.

Abstract: An apparatus for welding together coaxial tube sections which utilizes a welding electrode housing and a mounting housing. The welding electrode housing is to be clamped onto the tube sections and hold them in an abutting, coaxially aligned position. The welding electrode housing is then to be fixedly mounted onto the mounting housing with the welding procedure then being initiated. The mounting housing includes a structure required to produce the welding operation. The mounting housing is connectable to different welding electrode housings, each of which is to connect with a different size of tube to be welded.

Abstract: The outer shell of the linking housing (7) of the welding machine consists of a first casing (7a) and a second casing (7b), assembled together through a flat surface (44). The electrode support (10) is mounted to move in rotation in a bearing (30) fixed in the first casing (7a) about an axis of rotation (42). The shaft (40) for transmission of the rotation to the electrode support (10) is mounted to move in rotation in a bearing (28) fixed in the second casing (7b) about an axis of rotation (43). The axes (42) and (43) converge at a point 0 on the surface (44) and form an angle with the axis normal to the surface (44) at 0. The disalignment of the axes (42) and (43) can be adjusted by rotating the casings (7a, 7b) with respect to each other.

Abstract: A weldhead for welding small diameter tubing in confined spaces. The weldhead includes a welding body and a separable cartridge. The cartridge has a pair of collet clamps for gripping the two sections of tubing to be joined on either side of the weld joint and for maintaining the tubing in alignment during the welding operation. The weldhead body includes a circular rotor that is notched to fit around the weld joint when the weldhead is inserted into and latched to the cartridge. A tungsten electrode is disposed on the inner circumference of the rotor and is caused to orbit the weld joint by a motor driven gear train. A welding arc is established between the electrode and the tubing and the rotor is then driven so that the electrode orbits the weld joint. Motor speed and welding current are regulated to control the weld puddle size.

Abstract: An apparatus for welding together coaxial tube sections which includes a main housing within which is located a through opening within which is to be located the coaxial tube sections to be welded. A welding electrode is mounted within the main housing to be rotatable about the tube sections to effect the welding procedure. The welding electrode is mounted on a deflectable welding electrode mounting member which is to be moved to cause the welding electrode to physically contact the tubes in the welding area and then to be movable to cause the welding electrode to assume a spaced position establishing the desired welding arc. The coaxial tube sections are snugly held in position through the use of a metallic clamping plate arrangement. This clamping plate arrangement has formed therein a series of slots which is to provide for increased expansion of the size of the through opening so as to permit mounting of the tube welder on a greater size variance of tubes to be welded.

Abstract: The device for making a peripheral welding seam on a cylindrical tube (1) is attachable on the tube (1), is equipped with a rotary drive (15) for a rotational movement of the welding tool about the tube axis and is defined in that it has two rotatable rollers (10, 12) fastened to the device and arranged fixedly at a distance from one another in the peripheral direction and a third pivotable drive roller (15) connected to the drive. In the cross-sectional direction of the tube (1), the space between the rollers (10, 12, 15) has a larger dimension than the tube (1). When the dirve roller (15) is partially pivoted away, a lateral insertion orifice for the tube is consequently provided and likewise has larger dimensions than the tube (1).

Abstract: A tool having a rotating hollow electrode is provided power through a rotary electrical connection in the form of ball bearings and conductive lubricant, with a fixed hollow power supply fitting mounted in and insulated from a housing structure journaled in the bearings. Gas for welding is supplied through the hollow fitting and electrode which are in fluid communication.

Abstract: A plasma welding method has successive steps including pre-heating of members to be welded, tack welding of the members for tentatively fixing these members, keyhole welding for completely welding the members to each other, and finish padding. These steps are automatically conducted by a single plasma welding apparatus operative in accordance with a programmed sequence including data concerning the optimum conditions of operation in each step in relation to the conditions such as sizes and materials of the members to be welded.

Abstract: The invention is concerned with controlling weldpool penetration during root pass welding in an open butt joint defined in a workpiece to be welded by a welding torch with a welding wire being continuously fed from the welding torch to the joint to form a weldpool penetrating the joint, the workpiece and welding torch being movable relative to one another. A visual sensor is positioned ahead of the welding torch and in alignment with the joint for frontly viewing the weldpool at an angle of about 10.degree. to about 20.degree. relative to a line tangent to the workpiece at the weldpool, to thereby provide a full image of the weldpool defining a weldpool contour line, the sensor and welding torch being disposed on a common side relative to the workpiece.

Abstract: A track assembly for mounting a welding head assembly onto a pipe for the purpose of welding the pipe. The track assembly includes a flexible annular base which is to be located about the pipe in close proximity to the exterior surface of the pipe but spaced therefrom. Located between the annular base and the pipe are a plurality of spaced-apart foot pad assemblies. Each foot pad assembly includes a pair of contact pads which function to exert a continuous spring force between the annular base and the pipe. Each contact pad is connected to a separate spring assembly which can be mutually adjusted to vary the amount of spring force between the flexible annular base and the pipe. Mounted on the exterior surface of the annular base is a track which is to connect with the welding head assembly upon which the welding head operates to move circumferentially about the pipe. A latching assembly in the form of an over-center latching mechanism is used to secure together the free ends of the annular base.

Abstract: Welding tongs for connecting two abutting pipe ends to each other by arc welding, includes two rigid jaws, a clamping device in the form of two symmetrical clamping jaws guided in the rigid jaws in radial direction of the surface of a pipe, the clamping jaws having contact surfaces adapted to the surface of a pipe for holding at least one pipe end, two angle levers each being connected to a respective one of the clamping jaws, a tie rod connected to the angle levers, a pair of levers connected to the tie rod and operating in vicinity of an extended position thereof, an operating handle connected to the pair of levers, a spring member biased between the clamping jaws and the pair of levers, a track, a welding electrode disposed on the track, and a motor connected to the electrode for moving the electrode along the track.

Abstract: A steel tube working apparatus is composed of a clamping device consisting of a pair of clamps, a pair of projecting plates, means for actuating the clamps and the projecting plates, a pair of guide bars and a main body frame; a base plate having a pair of guide rollers fitting to the guide bars fixedly secured to its opposite ends; and working means connected to the base plate in a movable and rotatable manner. A cutting device, a beveling device, a welding device, etc. are selectively connected to the base plate as the working means.

Abstract: A pipe welder for the automatic welding of joints between end abutting stationary sections of pipe which uses a welding head assembly mounted on a track which is mounted about the pipe. The welding head is low frictionally supported by a roller assembly connected between edges of the track. The track includes gear engaging slots. A drive gear is to engage with the gear engaging slots. The drive gear is flexibly mounted on the welding head housing so as to be continuously biased into positive engagement with the gear engaging slots.

Abstract: An automatic welding apparatus for performing welding along the circumference of abutted pipe ends, wherein the apparatus can be taught and operate in accordance with data related to reference positions and welding paths along semicircumferences of the abutted ends. A welding head is driven along a guide attached to one of the two pipes. The welding head is first positioned to reference points and then moved along the guide in two upward directions to the ends of welding lines, thereby to teach the apparatus the welding operations to be performed. Subsequently, the apparatus is operated to carry out welding in accordance with the instructed operations.

Abstract: Welding carriage, including an articulated body having support wheel sets on its end sections, one of said end sections supporting a drive assembly movable toward and away from a track upon which the carriage travels, the drive assembly including two tandem drive wheels driven by an electric motor supported by the drive assembly. The carriage may support one welding head or plural welding heads, so that one or more weld beads may be formed as the carriage travels past a section of a welding groove.

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: A welding apparatus with monitor means including a welding torch having an electrode located in the vicinity of its forward end and supported at its rearward portion by a welding head for rotational movement about its longitudinal axis and back-and-forth reciprocatory movement along the longitudinal axis. The welding torch further includes an electric conductor covered at its outer periphery with an insulator and formed with a gas sump in the vicinity of the electrode. The electric conductor has defined therein a gas supply passageway for supplying gas shield gas, a bore for allowing an image guide and a light guide to extend therethrough, and a bore for allowing a fluid to flow therethrough to cool the electric conductor. The image guide and light guide have their forward ends located in the gas sump, so that they can command a view of outside through guide openings serving concurrently as gas ejecting ports for ejecting the shield gas therethrough.

Abstract: An elongate deformable ribbon drive rail for carrying a working apparatus having a toothed drive gear and support mechanism is provided in the form of a first narrow elongate strip of metal of width to carry the support mechanism, a second narrower strip of metal having a regular series of corrugations extending lengthwise thereof fixed to the first strip intermediate its edges at each valley of the second strip and adapted to be engaged by the toothed drive gear while the edges of the first strip engage the support mechanism.