Abstract: The invention relates to a method of monitoring the welding operation in a stud welding process, wherein a part (19) to be welded is immersed into the melt by moving the part (5) towards a workpiece (17), with a physical quantity depending on the force required for moving the part (5) being measured at least during the phase of immersion of the part (19) to be welded into the melt and the measured gradient of the physical quantity plotted against time being compared with a predetermined set gradient. Furthermore, the invention relates to a stud welding device for carrying out such a method.

Abstract: A short-cycle arc-welding system (10) and a method for welding elements (32), such as metal bolts (32) to components (34) such as sheet metal (34) includes a robot (12), having at least one arm (16) displaceable on at least two co-ordinate axes (x, y, z), a welding head base (20) fixed to robot arm (16), a welding head (22) displaceably mounted on welding head base (20), a retaining device (30) retaining an element, a lifting device (36) for setting and re-positioning retaining device (30) in relation to welding head (22), and a measuring system (44,46) determining the relative position between component (34) and element (32). Measuring system (44,46) has a control device (46), controlling lifting device (36) such that element (32) displaces towards component (34) until contacting component (34) to determine the relative position.

Abstract: A device and a method for short-cycle arc welding of elements (26) to components are disclosed, with a positioning mechanism (14) that holds a welding head (28) and can be positioned relative to a component (12), wherein the welding head (28) has a chucking mechanism (32) for holding an element (26), a linear motion mechanism (58) for advancing and retracting the chucking mechanism (32) relative to the welding head (28), and a feed channel (30) for feeding elements (26) to be welded into the chucking mechanism (32). The chucking mechanism (32) has radially movable chucking elements (34) that can be moved by a chucking means between an open position which permits axial passage of an element (26) from the feed channel (30) through the chucking device, and a chucking position in which an element (26) is chucked between the chucking elements (34).

Abstract: The present invention relates to a cooking appliance used for boiling or cooking food, or more particularly, to a cooking pot, which can rapidly heat water or food, and thereafter can suppress overflowing of water or food therein, while simultaneously maintaining its suitable temperature and pressure, thereby shortening its cooking time while enhancing its safety and convenience during cooking.

Abstract: A welding gun 10 has a collet for holding a stud with a flange and a shank at the tip of the welding gun. The collet comprises a tubular first collet member 17, secured to the tip, which elastically opens to a larger diameter than the stud flange, for holding the flange at the tip, and a tubular second collet member 22, secured to the tip of a piston rod 21 which extends from an air cylinder 11 provided in the aft portion thereof toward the first collet member, for, by the movement of the piston, picking up, accommodating, and holding the shank of a stud fed with its flange to the fore inside the first collet member 17.

Abstract: The invention relates to a rapid arc welding system (10) for welding elements (12) onto components (14). The inventive system comprises a welding head (16), a supply device (24) for supplying elements (12) to the component (14) and a control and power device (20). Said control and power device comprises a safety circuit for controlling the safety functions of the welding system (10) which allows an operation that is especially safeguarded from unauthorized use of the system in which an operation disruption is partially cancelled. In this partial operation mode, individual components of the system (10) can be activated selectively, especially for the purpose of maintenance.

Abstract: What is proposed is a joining system head (22; 170) for fixation to a movable frame (12), in particular to a robot (12), having holding means (66; 174) for an element (36) to be joined to a part (38), and joining drive means (64; 175) to move the holding means (66; 174) along a joining direction (40; 176) for joining. The said holding means (66; 174) is mounted on the joining system head (22; 170), rotatable about an axis (34) running transverse to the joining direction (40; 176).

Abstract: According to a first embodiment of the method, the stud holder is first positioned without a part to be welded at a certain distance from the tool surface. A part to be welded is then provided. When the welding axle moves towards the workpiece, the path that needs to be travelled in order to bring the part to be welded and the workpiece into contact is detected. Conclusions regarding the presence or absence of a part to be welded are then drawn, based on the previous distance between the stud holder and the workpiece and the path travelled. According to another embodiment, the stud holder is moved towards the workpiece with a part to be welded until contact is detected. If, after contact is detected, further movement of the welding axle is possible as a result of the part to be welded being pushed into the stud holder, this is interpreted as an indication of the presence of a part to be welded.

Abstract: A process and a system are proposed for short-time arc welding elements, such as for example metal studs, on to components, such as for example metal sheets, wherein an element in the context of a welding operation is initially raised in relation to the component, a welding arc is formed between the element and the component, and the element is lowered again, the lifting height of the element in relation to the component being detected at least within a time segment between raising and lowering of the element. The initiation of the lowering operation and/or the lowering operation itself is controlled as a factor of the detected lifting height such that a previously specified total welding time is achieved.

Abstract: A method of joining plates includes the steps of providing a one or more studs having a head, a barrel and a weld tip. The plates and studs are arranged such that a first plate having at least one hole is located between the studs and a second plate with each stud aligned with a hole and contacting the second plate. Current is passed through the stud using the stud head and the second plate as electrodes to melt the weld tip bonding the stud to the second plate. The studs are arranged such that an air gap between the studs and the first plate prevents arcing during the welding step. Pressure and heat may be applied to compress the barrel such that the stud functions as a rivet. Alternatively, the barrel may remain uncompressed to provide a pin allowing relative rotation between the plates.

Abstract: A process and a system are proposed for short-time arc welding, in particular for stud welding, with the step of sampling a welding parameter, in particular the arc voltage (U), during at least one time segment (Ts) of the welding operation, in order to detect disturbances, wherein the measurement curve determined from the sampling operation is smoothed and subsequently wherein at least one tolerance curve is generated which lies at a previously adjustable distance from the smoothed measurement curve, and subsequently the unsmoothed measurement curve is compared with the tolerance curve in order to detect high-frequency disturbances.

Abstract: The invention relates to a method for positioning a welding bolt (15), held in a bolt welding head (3), whereby the robot (5), to which the bolt welding head (3) is fixed, moves the bolt welding head sideways until a touch sensor (21) contacts a side wall (25) of a workpiece. The position of the side wall (25) is thus detected and the bolt welding head (3) can be moved through a set amount (Y) into a welding start position, from whence the welding bolt (15) can be welded to the workpiece (9) by the displacement in the direction of travel (V). The welding bolt (15), thus, always has the required separation (Z) from the side wall (25), independent of tolerances in the workpiece.

Abstract: A reinforcement butt stud welding method and a device therefore, capable of butt-welding a stud reinforcing bar coaxially to the end portion of a horizontally-laid existing reinforcement in a small work space; and a repairing/expanding method for a ferroconcrete structure. The reinforcement butt stud welding method includes the steps of fitting an earth clamp over the periphery of the end portion of the existing reinforcement, fitting an annular stud base that is a heat-resisting, insulating material to the conductor surface of the earth clamp by being pressed against the conductor surface, bringing the tip end of a stud reinforcing bar, loaded in a stud welding gun, into contact with the end face of the existing reinforcement, and keeping a ferrule disposed around the tip end portion of the stud reinforcing bar joined to the stud base to complete stud welding.

Abstract: A weld-on part made of aluminum or an aluminum alloy, such as but not limited to a stud (1), which has a surface which is at least partially provided with a layer (5) which contains a titanium containing material. The stud (1) is treated with a chrome-free passivating solution which imparts corrosion resistance while simultaneously causing a layer (5) of titanium containing material to be formed on at least a portion of the surface of the stud (1). The layer (5) of titanium containing material permits the stud (1) to be satisfactorily welded to a surface, without the occurrence of arc jumping or blowing, in part, by lowering contact resistance during the welding process.

Abstract: The invention relates to a method for welding a bolt (19) onto a workpiece, using a bolt-welding device and to a bolt-welding device. A force is applied to the drive shaft (11) using a switchable unit (29), said force exerting a resistance against a displacement of the drive shaft (11). The drive shaft (11) is moved by an electromagnetic linear drive (5) acting in an axial direction. The unit (29) can prevent the movement of the drive shaft (11) and can fix the latter in position, in such a way that the linear drive (5) can be switched to a currentless state. In addition, the unit can dampen the movement of the drive shaft (11).

Abstract: The invention relates to a multiple stage method for arc-welding a bolt (3) to a metal structure (1), said bolt (3) having a flange (5) at the end that is to be welded on. The actual welding process is preceded by a cleaning method that is carried out by means of an arc. Said cleaning method consists of two or more stages. It is crucial to control the arc and the distance between the bolt (3) and the structure surface (7) in such a way that only cleaning takes place, without causing premature welding. While during the first cleaning state, only a small surface is cleaned intensively, in the second stage, a larger surface is cleaned due to a greater distance between the bolt (3) and the structure surface (7). Separation through interruption of the arc and maintenance of the bolt (3) in a stationary position at a distance from the structure surface (7) must take place between the first and second cleaning stages.

Abstract: A process and a system are proposed for short-time arc welding, in particular for stud welding, with the step of sampling a welding parameter, in particular the arc voltage (U), during at least one time segment (Ts) of the welding operation, in order to detect disturbances, wherein the measurement curve determined from the sampling operation is smoothed and subsequently wherein at least one tolerance curve is generated which lies at a previously adjustable distance from the smoothed measurement curve, and subsequently the unsmoothed measurement curve is compared with the tolerance curve in order to detect high-frequency disturbances.

Abstract: A process and a system are proposed for short-time arc welding elements, such as for example metal studs, on to components, such as for example metal sheets, wherein an element in the context of a welding operation is initially raised in relation to the component, a welding arc is formed between the element and the component, and the element is lowered again, the lifting height of the element in relation to the component being detected at least within a time segment between raising and lowering of the element.

Abstract: The invention relates to a method of monitoring the welding operation in a stud welding process, wherein a part (19) to be welded is immersed into the melt by moving the part (5) towards a workpiece (17), with a physical quantity depending on the force required for moving the part (5) being measured at least during the phase of immersion of the part (19) to be welded into the melt and the measured gradient of the physical quantity plotted against time being compared with a predetermined set gradient. Furthermore, the invention relates to a stud welding device for carrying out such a method.

Abstract: The present invention relates to a lift-and-strike welding process. In a first step, e.g. an aluminum surfaces (5) of a component is cleaned by striking an arc and then the element (4) to be connected is welded on by means of at least one second voltage. Besides a lift-and-strike welding apparatus, a further lift-and-strike welding process is also provided, wherein an electric cleaning current flows between a surface (5) of a component and an element to be welded thereon, in that the component rests on the surface (5) and then the element (4) is lifted off the surface (5) up to an approximately, in terms of time, constant distance for removing a coating from the surface (5) by means of an arc, then the current changes its polarity, wherein afterwards at least one welding current is produced and then the element (4) is welded to the surface (5).

Abstract: According to a first embodiment of the method, the stud holder is first positioned without a part to be welded at a certain distance from the tool surface. A part to be welded is then provided. When the welding axle moves towards the workpiece, the path that needs to be travelled in order to bring the part to be welded and the workpiece into contact is detected. Conclusions regarding the presence or absence of a part to be welded are then drawn, based on the previous distance between the stud holder and the workpiece and the path travelled. According to another embodiment, the stud holder is moved towards the workpiece with a part to be welded until contact is detected. If, after contact is detected, further movement of the welding axle is possible as a result of the part to be welded being pushed into the stud holder, this is interpreted as an indication of the presence of a part to be welded.

Abstract: A method for attaching parts together includes several steps. The parts are positioned for drawn arc welding the parts together. A drawn-arc-weld ferrule including metal is obtained. The ferrule is positioned for use in drawn-arc-welding together the positioned parts. The ferrule is cooled. The positioned parts are drawn arc welded together using the positioned ferrule. In a first expression of an embodiment, a drawn-arc-weld ferrule includes metal. In a second expression of an embodiment, a drawn-arc-weld ferrule includes separate segments each including metal.

Abstract: A process and apparatus for welding a metal component to a metal workpiece. The component typically comprises a metal weld region and a threaded connector region and the apparatus includes a weld head comprising a nozzle for holding the weld region of the component adjacent the workpiece. The weld head induces a weld arc between the weld region of the component and the workpiece to create a weld pool of molten material. The weld head subsequently moves the weld region into the weld pool to permanently join the component to the workpiece. The apparatus further comprises a pressurized fluid source and a fluid flow control means for directing the pressurized fluid between the weld head and the component an weld pool so as to deflect any airborne fluid residue of the weld pool away from the connector region of the component.

Abstract: A method for attaching parts together includes several steps. The parts are positioned for drawn arc welding the parts together. A drawn-arc-weld ferrule including metal is obtained. The ferrule is positioned for use in drawn-arc-welding together the positioned parts. The ferrule is cooled. The positioned parts are drawn arc welded together using the positioned ferrule. In a first expression of an embodiment, a drawn-arc-weld ferrule includes metal. In a second expression of an embodiment, a drawn-arc-weld ferrule includes separate segments each including metal.

Abstract: A reinforcement butt stud welding method and a device therefore, capable of butt-welding a stud reinforcing bar coaxially to the end portion of a horizontally-laid existing reinforcement in a small work space; and a repairing/expanding method for a ferroconcrete structure. The reinforcement butt stud welding method comprises the steps of fitting an earth clamp over the periphery of the end portion of the existing reinforcement, fitting an annular stud base consisting of a heat-resisting, insulating material to the conductor surface of the earth clamp by being pressed against the conductor surface, bringing the tip end of a stud reinforcing bar, loaded in a stud welding gun, into contact with the end face of the existing reinforcement, and keeping a ferrule disposed around the tip end portion of the stud reinforcing bar joined to the stud base to complete stud welding.

Abstract: A blow feed weld gun for welding a nut to a metal substrate is disclosed. The blow feed weld gun has an air feed mechanism and a nut drive mechanism. The nut drive mechanism contains a primary piston assembly located within a cylindrical working chamber. The primary piston assembly is coupled to a first driven piston which is hollow and defines a passage which welding gasses and/or air can be delivered to the threads of a threaded weld nut.

Abstract: The invention relates to a multiple stage method for arc-welding a bolt (3) to a metal structure (1), said bolt (3) having a flange (5) at the end that is to be welded on. The actual welding process is preceded by a cleaning method that is carried out by means of an arc. Said cleaning method can be advantageously carried out in two or more stages with different effects. It is crucial to control the arc and the distance between the bolt (3) and the structure surface (7) in such a way that only cleaning takes place, without causing premature welding. While during the first cleaning state, only a small surface can be cleaned intensively, in the second stage, a large surface can be cleaned due to a greater distance between the bolt (3) and the structure surface (7). Separation through interruption of the arc and maintenance of the bolt (3) in a stationary position at a distance from the structure surface (7) must take place between the first and second cleaning stages.

Abstract: A stud welding gun for alternatively welding studs of a first and second length to base members. The gun includes a stud feed member for moving a stud toward a stud holder. The gun further includes at least two stud cartridges each having a plurality of studs in side by side array and opposed end walls extending between first and second side walls. A first cartridge has end walls spaced a distance equal to studs having the first length. A second cartridge has end walls spaced a distance equal to studs having the second length. At least one of the side walls of each cartridge extends to a pre-determined overall length. A housing is adapted to receive the cartridges placing the studs in the path of the stud feed member. The gun includes a stud mover that sequentially moves the studs into the path of the stud feed member.

Abstract: A process and apparatus for welding a metal component (28) to a metal workpiece (40). The component (28) typically comprises a metal weld region (36) and a threaded connector region and the apparatus includes a weld head comprising a nozzle (8) for holding the weld region (36) of the component (28) adjacent the workpiece (40). The weld head induces a weld arc between the weld region (36) of the component (28) and the workpiece (40) to create a weld pool of molten material. The weld head subsequently moves the weld region into the weld pool to permanently join the component (28) to the workpiece (40). The apparatus further comprises a pressurised fluid source and a fluid flow control means for directing the pressurised fluid between the weld head and the component and weld pool so as to deflect any airborne fluid residue of the weld pool away from the connector region of the component (28).

Abstract: Apparatus and process for safely welding a stud into an overhead workpiece that includes a ferrule having an interrupted perimeter surrounding the stud for contact with the overhead workpiece and a support assembly for connection to a stud gun including a shield surrounding the support assembly and having a continuous perimeter defining a free space by being spaced from the stud and wherein the free space is in communication with the interrupted perimeter of the ferrule. The free space has a width and depth sufficient to receive and contain all molten substances produced during the welding. A fire resistant material is positioned within the free space to hold all these molten substances to thereby safely protect the operator of the stud gun from the gravity induced falling molten substances.

Abstract: A disposable collet adapter for attaching a workpiece to a stud welding tool. One end of the resilient collet adapter slideably mounts to one end of a workpiece and the opposed end slideably attaches to the electrode of the stud welding tool. The opposed ends of the collet adapter are individually tailored so that of the workpiece and the electrode may have distinct cross-sectional profiles. After a welding operation, the collet adapter can be discarded or reused.

Abstract: Apparatus and methods for arc welding a stud to a workpiece without the use of a ferrule are disclosed. Apparatus according to the invention include a stud arc welding gun having a spacer at a distal end thereof, and a chuck adapted to receive a stud having a diameter of more than about ⅜ inch. A stud feeding device is coupled to the gun for automatically loading studs into the gun. The stud feeding device can include a bowl feeder and a stud feeding conduit via which studs are transferred from the bowl feeder to the stud gun. A gun positioning device, such as an arm of a robot, is coupled to the gun, and automatically positions the gun such that the spacer is against a receiving surface of the workpiece. A controller coupled to the stud gun initiates a stud arc welding process to arc weld the stud to the workpiece.

Abstract: A fastening element for fastening on or in a component, in particular a T-stud or punch rivet, has a fastening end. The fastening element has, at a guide end remote from the fastening end, a recess for receiving a tool end piece which fits into the recess and by means of which the fastening element can be positioned.

Abstract: The invention relates to a method of manufacturing a welding stud from a wire by cold-working and by hardening and tempering. The welding stud particularly serves to be welded to a workpiece by means of an electric stud welding method and consists of a mounting portion and a welding portion. According to the invention, the wire is first pre-treated by hardening and tempering and is then cold-worked in such a way that the mounting portion and the welding portion have different strengths.

Abstract: A cover for a transmission torque connector having loosened or otherwise damaged bolts is repaired for reuse. One method includes removing a loosened bolt, and plugging and countersinking the bolt hole. The countersunk area on the exterior of the cover provides an area to form a welding bead to permanently seal the whole. The surface is then prepared for welding a stud onto it to complete the repair. In the case where the original bolt is damaged but has not been loosened, the top part of the bolt can be cut off so that the bolt can serve as the plug.

Abstract: A stud welding gun for alternatively welding studs of a first and second length to base members. The gun includes a stud feed member for moving a stud toward a stud holder. The gun further includes at least two stud cartridges each having a plurality of studs in side by side array and opposed end walls extending between first and second side walls. A first cartridge has end walls spaced a distance equal to studs having the first length. A second cartridge has end walls spaced a distance equal to studs having the second length. At least one of the side walls of each cartridge extends to a pre-determined overall length. A housing is adapted to receive the cartridges placing the studs in the path of the stud feed member. The gun includes a stud mover that sequentially moves the studs into the path of the stud feed member.

Abstract: A conventional stud welding tool is substantially improved by providing the tool with an electrode with an adjustable aperture capable of grasping studs with a variety of sizes. The adjustable aperture is in the form of a chuck having a plurality of sliding fingers movable along intersecting axes and positionable along these axes to form an aperture of a desired diameter. The fingers have a threaded exterior surface, and the chuck includes a wheel having a threaded interior surface for engaging the threaded exterior surfaces of the fingers for moving the fingers along their axes in response to rotation of the wheel. The chuck is automatically closed and opened by a control circuit in response to the condition of a variety of sensors connected to the control circuit. Also, a collating strip of studs and a feed assembly is used to automatically deliver studs to the electrode under control of the control circuit.

Abstract: Stud welding device with an axially displaceable adjusting element (3, 17) for displacement from a front position into a rear position and back, in which a magnetic field and a coil (15) interact in such a way that, when the coil (15) is connected to a controllable current source (41) an axial force is produced in order to displace the adjusting element (3, 17), the movement of which is transmitted to a stud holder (2), characterized in that the coil (15) is rigidly arranged on a hollow body (14) which is connected to the adjusting element (3, 17) and is arranged axially movably in an air gap (13) between a magnetizable core (8) and a magnetizable sheath (10), the magnetic field being conveyed via at least one yoke (9) connecting the core (8) and the sheath (10) while passing radially through the coil (15), the coil exerting on the adjusting element (3, 17) an axial force acting only in one direction as a function of the direction of current during current control.

Abstract: A stud welding gun (20) includes a frame (36) which extends outward from a handle assembly (24). A chuck (46) on an outer end portion of the frame holds a stud (22) while the stud is being welded to a base member. A stud supply (60) is connected with the frame (36) and includes a housing (64) which receives a stud retainer or magazine (70) containing a linear array (72) of studs (22) disposed in a side-by-side relationship. The studs (22) are fed from the retainer (70) in the stud supply housing (64) to a receiving location (62). A stud feed member (76) is manually moved from a retracted position to an extended position to sequentially feed studs (22) to the chuck (46). The size of a linear slot (88) in the stud supply housing (64) can be varied to enable retainers (70) containing studs (22) of different lengths to be positioned in the stud supply housing.

Abstract: An electric oven includes a front door, upper and lower heating tubes mounted in the oven near a top and a bottom thereof, respectively, an oven rack fixed between the upper and the lower heating tubes, a grease drip tray removably fixed below the lower heating tubes for catching dropped grease drips, a frying pan fixed above the upper heating tubes, and a top lid that may be pivotally and upward turned open for access to the frying pan. The top lid is provided on an inner surface along outer edges thereof with a perpendicular and continuous flange, such that when the top lid is in a closed position, the flange tightly contacts with top edges of the frying pan to seal the same. The oven is further provided on two lateral inner wall surfaces with two sliding channels, so that the grease drip tray may be removed from its lower position in the oven to fix in and between the two sliding channels for catching grease drips dropped from the frying pan.

Abstract: An apparatus for repairing high temperature process vessels while at or near their operating temperatures, which may be up to 3000.degree. F. The apparatus includes a lance, a welding apparatus at the distal end of the lance, and power supply and control cabling within the lance. The welding apparatus is contained within a protective housing and both the lance and the housing may be either air- or water-cooled.

Abstract: A system for automatically feeding studs to the electrode of a manual stud welding tool. The system comprises a magazine associated with the tool. The magazine receives a tandem row of studs mounted in and collated by a disposable mounting and collating strip assembly. A drive assembly is associated with the magazine to advance the mounting and collating strip assembly such that each stud, when it becomes the forwardmost stud of the tandem row, is properly positioned with respect to the tool to be welded to a workpiece.

Abstract: The device proposed is designed to weld together at least two parts (1, 2) using arc-welding or resistance-welding, in particular pressure arc-welding, techniques. An arc is struck across a gap between the two parts (1 and 2), thus causing them to melt. In oder to ensure a very precisely defined vertical gap between the parts, the second part (2) is first placed on the first. The final position, determined by a program-control unit (12), is measured by means of a travel-measurement instrument (10). Starting from this "zero position", the bolt is lifted through a freely programmable distance and the main welding current activated. On expiry of the prescribed period of time, the bolt on the second part (2) is moved towards the first part (1), this movement also being carried out under program control.

Abstract: To form a welded joint between a fastening means (1) and a structure (2), a fastening means (1) with a holder (3) and a connecting element (4) is proposed. The holder (3) essentially consists of an electrically insulating material. The connecting element (4) consists of a substantially electrically conductive material. The holder (3) substantially surrounds the connecting element (4). The connecting element (4) has a contact face (5) located inside the holder (3). The holder (3) has a through-orifice (6) at least partially overlapping the contact face (5). A contact piece (7) of an electrically operated welding device is introduced through the through-orifice (6).

Abstract: In a welding method for the connection of a component (6) to a workpiece (7) by means of an arc between the component end and a welding point on the workpiece (7), the arc voltage is set and is monitored continuously during the welding process. The component lift is in each case automatically adjusted accordingly.

Abstract: To evaluate the quality of a weld produced by a stud welding process, the time characteristic of the resistance R (t) between the stud and the workpiece is determined. If the resistance or the increase in resistance or the rate of increase of the resistance exceeds a predetermined value during the arc period, this is an indication of arc blow effects, of spattering, and of the arc burning outside the bonding area--effects which impair the quality of the weld. Upon detection of a predetermined resistance increase, the weld process is terminated by turning off the weld current or by immediately immersing the stud into the melt of the workpiece. Alternatively, the characteristic of the resistance over time detected in a first welding process can be used to set the parameters for subsequent welding processes.

Abstract: The invention relates to a method of welding weld studs to a workpiece, in particular of aluminum in each case, by the stroke ignition method, in which the stroke height(s) of the weld stud (1) is altered as a function of the measured arc voltage and optionally of the arc firing time. In particular, the stroke height(s) of the stud (1) can be increased during the occurrence of short circuits, i.e. during a sudden drop in the arc voltage, preferably in predetermined steps. The weld stud is immersed into a pool of melt after a predetermined period of time of between 5 and 10 ms after the welding current has been switched off. The polarity of the stud or of the workpiece is changed at least once during the welding process. The welding current is interrupted for a predetermined period of time for this purpose. The method leads to an improved, readily reproducible quality of weld.

Abstract: An electric welding device for welding a fastening element (4) having a through-duct (17) on a workpiece is proposed. The welding device comprises a conveying and holding system (1) having a guide member (2) with a guide duct (3). The fastening element (4) is supplied to the guide duct and is held in one of its ends during the welding process. Within the guide duct there is arranged a loading member (6) which is capable of moving to and fro in the longitudinal direction thereof and has a head (7) which can be brought to rest on the fastening element (4). The loading member has a duct (9) with an inlet (10) and an outlet (11) formed on the head (7). A gas supply duct (12) opens into the guide duct (3). The loading member (6) closes the gas supply duct (12) in a first position. In a second position, the loading member (6) connects the inlet (11) to the gas supply duct (12) so a gas flows to the welding position during the welding process.

Abstract: The invention relates to a process for the application of components strung together in the manner of a belt onto workpieces in which the components are intermittently brought successively into a separating position for a respective component. The component halted in the separating position is initially grasped by a spatially movable jointing tool brought to the separating position over a free path, the jointing tool being held in its position defined by the halted component, the grasped component then severed from the subsequent component and is finally transferred by the jointing tool into the respectively desired jointing position remote from the separating position, in which the component is fastened on the workpiece, for example by electric arc welding.

Abstract: A new adjustable collet for stud welding employs a plurality of electrically energizable jaws coordinated to firmly grasp studs of various shapes, sizes and orientations while welding them to a work surface. This adjustable collet will also ensure better contact with the stud and thus reduce the likelihood of arcing and faulty welds. Premature collet wear will also be averted by reducing the amount of sliding contact between the collet and the stud.