Showing papers on "Spot welding published in 1977"

Process and apparatus for monitoring the quality of weld spots produced by resistance spot welding

Abstract: The invention relates to a method and apparatus for monitoring the quality of weld spots produced by resistance spot welding according to which a weld spot which has just been made is observed by means of a video camera sensitive to infrared radiation at a well determined instant of its cooling, with a view to comparing it with a reference weld spot observed previously under the same conditions; the value and passage of the welding current is controlled by means of the video signal and the synchronization signals coming from said camera, which signals are exploited to make an image reconnaissance by counting scanning lines or dots defined along the lines by a clock, when this video signal becomes greater than an electrical voltage representative of the level of emission of infrared radiation of the periphery of the reference weld spot.

Welding wire feed system

Abstract: The invention relates to a welding wire feed system for feeding welding wire over a considerable distance from a remotely located wire storage spool to a welding gun through the use of straight lengths of angularly related conduit and intermediate low friction wire direction changing devices.

Electrical connection between aluminum conductors

Abstract: An electrical conductor connection between at least two aluminum conductors which includes a weld nugget having a substantially cylindrical cross-sectional configuration perpendicular to the major surfaces of the aluminum conductors. The ends of the weld nugget are convexly cupped and extend outwardly past the major surfaces of the aluminum conductors to provide visual verification of joint integrity. The electrical conductor connection is formed by a method which includes providing an aperture in one of the conductors to be joined and providing a recessed backup against the other conductor, aligned with the aperture. Timed, multiple sequence MIG arc spot welding provides a weld nugget having the desired shape and diameter at the interface or throat between the two conductors. The method also enables the welding operation to be performed out of position, without sag or run of the molten pool of aluminum.

Multi-spot welding apparatus

Abstract: A multi-spot welding arrangement in which a jig table on the front surface of a machine frame has a plurality of welding guns located along the shape or contour of the workpiece to be processed or worked. An electric supply has a plurality of units which are connected to the welding guns through respective electric supply cables. A pressure applying mechanism has a plurality of operation cylinders which are connected to the welding guns through respective flexible wires, and is located on the rear side and the upper side of the machine frame. The machine frame, moreover, has a front frame and a rear frame which are coupled together in a detachable manner. The jig table and the pressure applying mechanism are located on the front frame, and the electric supply is provided on the rear frame.

Vibration-damping and sound insulating board having excellent spot welding property

Abstract: PURPOSE: To prepare a vibration-damping and sound insulating board useful as car parts, etc. and having improved spot welding property because of improved electrical conductivity, by adding metal powder to the resin layer of a sandwich composite board consisting of a couple of outer metal layers and an inner resin layer. COPYRIGHT: (C)1978,JPO&Japio

Ultrasonic spot welder

Abstract: An ultrasonic spot welder is disclosed with a reed of resonant length arranged to be vibrated in a flexural mode for spot welding both plastics and metals. The reed has a non-circular cross section with major and minor transverse dimensions. Vibratory energy is transmitted to the reed in a direction perpendicular to its major transverse dimension.

Large surface heat exchanger panels prodn. for space heating - using two dimpled rolled metal or plastics sheets seam welded at edges and spot welded in dimples

Abstract: Large surface area heat exchangers are produced from two sheets of rigid material of approx. the same width. At least one of these has been subjected to a forming process, e.g. rolling, to create a pattern of depressions or dimples across its surface. The two sheets are continuously laid one on the other and then fixed mechanically e.g. by spot welding in the dimples. The edges are sealed e.g. by seam welding to give a water-tight joint. Both the sheets can have a pattern of dimples. The joint can be by bonding or welding and the sheets made from metal or plastic. A plastic coated metal sheet can be used and heated to just above the melting point of the plastic to give the bond. Used e.g. for domestic space heating. PErmits large areas of heat transfer to be created without the need for a number of pipe connections as between a number of smaller units.

Connection winding spot welder - has pulsed current operated and penetration controlled main and return electrodes on commutator riser and face respectively

Abstract: The welder comprises a main electrode (7) and return current electrode (6) which bear on the commutator riser and face respectively and are applied to each segment in succession. Welding current is provided from a pulsed generator (8, 9, 10). The depth to which the main electrode (7) presses into the top of the riser during a current cycle is detected (13) and used to control the cycle length of the current. The depth signal (13) is compared with a reference (21) in a comparator (20) and used to interrupt the current when parity of signals is reached. The number of such cycles per weld can be preset. Control of electrode penetration removes the risk of damage to or destruction of the riser by maintaining electrode pressure when the metal is plastic or molten.

Electrode system for spot welding aluminum and other difficult-to-weld materials

Abstract: ELECTRODE SYSTEM FOR SPOT WELDING ALUMINUM AND OTHER DIFFICULT-TO-WELD MATERIALS ABSTRACT OF THE DISCLOSURE An electrode system for spot welding difficult-to-weld materials, such as aluminum, wherein a pair of spaced apart electrodes, one of which is a roller, clamp the overlapped strips of material to be spot welded. Mechanism moves the roller electrode toward and away from the other electrode, and other means is operated respon-sively to this movement for indexing the roller electrode incrementally circumferentially to successively present a new surface to the work held between the electrodes. A control circuit applies DC power to the electrodes such that the roller mentioned has the positive polarity and the other electrode the negative polarity.

Protecting method for spot welding electrode

Abstract: PURPOSE: To simply and easily protect the spot welding electrode and to secure the quality of welding member, by applying necessary quantity of electrode protecting agent for removing contaminant at a suitable time at the time of carrying out spot welding operation blowing against the upper and lower processing face of electrode tip end of spot welding machine. COPYRIGHT: (C)1979,JPO&Japio

Resistance welding apparatus and method

Abstract: In combination with a resistance spot welding machine for welding superimposed electrically conductive members an improved apparatus for and method of cleaning welding electrodes and associated portions of the members to be welded are provided utilizing inert gas cooperating with electrical circuitry such that a sequential cleaning of each electrode and its portions are provided which is self starting and ending as a function of the presence of sufficient inert gas.

Mechanical aspects of spotvvelded joints in heat-treated lovvcarbon mild-steel sheets

Abstract: Mechanicalproperties of the spot welds made in martensitic, bainitic, cold-rolled, and subcritically annealed sheets produced from the same basic low-carbon mild steel have been assessed. Although the welds made in the stronger materials were able to withstand greater tensile shear loads than those made in weaker materials, the U-tensile strengths of the welds made in allfour materials were similar. The effects of the speed of tensile shear testing were determined, and it was found that, even at high testing speeds, the welds made in the stronger materials retained their load-bearing advantage over the welds made in the weaker materials. Tensile shear impact strengths of these welds were found to be inversely related to the yield strength of the parent sheet. The behaviour of the spot welds under fatigue stresses was determined. The results showed that the endurance limits of the spot welds in the ‘as-welded’ condition were low and comparable, and it was evident that the metallurgical condition of...

Spot welding tongs using rigid clamping arms - esp. for welding control rod guide tubes in nuclear reactors

Abstract: Spot welding tongs employed for joining workpieces which are not readily accessible, such as control rod guide tubes for nuclear reactor fuel elements, where the tubes are to be welded to fixing straps on spacer grids. The tongs consist of two coaxial tubes, one sliding inside the other, and each tube carries the welding current to an electrode. One electrode is mounted radially on the end of each tube, and the axial movement of the tubes is used to clamp the workpieces between the two electrodes. A conventional mechanical design is pref. employed to prevent the two coaxial tubes from rotating w.r.t. each other; and the electrode arms may be mounted tangentially on the tubes. In conventional spot welding tongs, the electrode carrier arms beng outwards when clamping pressure is applied so that the workpiecs are not correctly clamped between the electrodes; the result is faulty welds and malalignment of the workpieces. The invention eliminates such problems.

Resistance welding of metals with high electrical and thermal conductivity

Abstract: A simple device for welding metals with high electrical and thermal conductivity is described. The use of the device, which was adapted from a commercially available carbon deposition unit, for welding 0.0127 and 0.0507‐cm‐diam Ag, Au, and Pt wires is discussed.

Nonflammable fabric of stainless steel wire reinforced yarns - has stainless foil cladding spot welded to fabric surfaces

Abstract: An inflammable fabric of asbestos or synthetic yarns, is woven from yarns spun with a stainless steel wire reinforcement having a dia. of 0.15-0 2mm. A metal foil of stainless steel 0.05 mm thick at the most, may be pressed against one or both surfaces of the woven fabric and secured to it by spot welding. The product is impermeable to gas and fluids, resistant to friction and completely uninflammable. It is capable of withstanding high mechanical and thermal loading and is particularly applicable to plastic compensators in pipelines.

Simultaneous dressing of electrodes in multi spot welding machines - using swivel fixture contg. row of driven grinding wheels

Abstract: A device for dressing the electrodes on multi-spot welding machines, during preselected welding pauses, consists of a grinding device provided with several grinding wheels mounted on one or more shafts driven by V-belts and a motor. The device is mounted on a pivot arm so that it can be swung into the working position. A slide carrying the grinding wheels can be driven forwards and backwards between the electrodes and the grinding wheels can be moved vertically or swung on a swivel to grind the working faces of the electrodes.

Resistance welded joints for metal furniture or consumer goods - where one workpiece is bent at right angles to make a T:joint

Abstract: A T-joint is made by resistance welding, where one workpiece (2) is bent in a right angle at one or both ends; the other workpiece (1) is aligned so it is at ca. 90 degrees w.r.t. the longitudinal direction of end(s). Alternatively, the two bent ends of the workpiece (2) may pass through two holes in a third workpiece and then be welded to piece (1). Used for mfr. of steel furniture; consumer goods; ladders; cagework, etc. Projection welding is frequently used for such joints, but it is difficult to obtain consistently strong joints. The invention provides uniform heating of the workpieces to achieve reliable welds.