A welding head for welding the extremities of two sections of rail and comprises two half-heads (10) aligned and sliding with regard to one another in a longitudinal direction. Each half-head comprises grip mechanism (12, 13) for grasping a respective section of rail and two electrodes (16) suitable for contact with respective sections of rail in order to carry out a flash butt weld. The head also comprises traction actuator mechanisms (20) which extend in a longitudinal direction and are connected to the two half-heads (10) to shift the two half-heads in a longitudinal direction one towards the other, the traction actuator mechanism (20) having a stroke suitable for allowing, during a cycle of welding two sections of rail, simultaneous regulation of rail tensions.

The invention relates to a method of welding of at least two metal-based materials (5, 7), non-weldable directly to each other with resistance welding. At least one spacer (6) is joined by welding on at least one of the two surfaces of a material (5) in every interstice between two surfaces of materials to be welded. The welded spacer (6) is utilized so that resistance welding is focused to the surface of the material (5) with the spacer (6) to melt at least one spacer (6) located on the heat affecting zone in order to achieve a weld between the metal-based materials (5, 7).

A current applying apparatus includes a pair of electrodes configured to contact a workpiece to apply an electric current to the workpiece, and a bus bar arranged to extend along the workpiece. At least one of the electrodes includes a moving electrode configured to move relative to the bus bar and the workpiece such that an electric current flows between the bus bar and the workpiece through the moving electrode, the moving electrode being connected to the bus bar so as to be movable relative to the bus bar, and the moving electrode being configured to contact the workpiece so as to be movable relative to the workpiece.

A seam welding device sandwiches between a first roller electrode and a second roller electrode a laminate, which is formed by laminating a plurality of workpieces and disposing the thinnest workpiece, which has the smallest thickness among the workpieces, on the outside, to carry out seam welding. The second roller electrode, which is in contact with the thinnest workpiece, is disposed further along the direction of welding progress than the first roller electrode.

An automatic welding machine comprising clamping units, pushing pneumatic cylinders, a compression drive, and pressing and supplying welding current contact welding rollers. The automatic welding machine also comprises a die positioning of the ribs with respect to the pipe and clamping units, windows for the passage of rollers, and a mechanism for positioning the die. The clamping units have a mechanism for adjusting the position of the longitudinal axis of the compression drive of the roller, consisting of a compression drive guide, two regulators, a compression drive housing, a ball joint assembly, an adjusting lock nut, a fixing screw, and two bronze crackers. A mechanism for adjusting the contact welding roller comprises a roller, bushings, nuts, cheeks, and threaded elements.

An apparatus and method for welding electrode tabs protruding from an electrode assembly to each other, which may include a guide part configured to gather the electrode tabs; and a welding part configured to weld the electrode tabs gathered by the guide part on a predetermined welding area. The guide part may be configured to press the electrode tabs toward the electrode assembly, while moving toward the electrode assembly, such that a length from the electrode assembly to the welding area increases in at least a portion of the electrode tabs before being welded by the welding part. Accordingly, some aspects of the present invention may prevent the electrode tabs from disconnecting.

An apparatus and method for welding electrode tabs protruding from an electrode assembly to each other, which may include a guide part configured to gather the electrode tabs; and a welding part configured to weld the electrode tabs gathered by the guide part on a predetermined welding area. The guide part may be configured to press the electrode tabs toward the electrode assembly, while moving toward the electrode assembly, such that a length from the electrode assembly to the welding area increases in at least a portion of the electrode tabs before being welded by the welding part. Accordingly, some aspects of the present invention may prevent the electrode tabs from disconnecting.

A manufacturing method of an electronic device, that accommodates a gyro element as an electronic component in an inner space formed by a base and a lid as a lid body, includes: preparing the lid in which a groove is provided on the rear surface which is welded with the base, and an opening area of the groove on the inner space side which is greater than an opening area on the outer periphery side of the lid; welding, first, the base and the lid at a portion excluding an unwelded portion that includes at least apart of the groove, of a planned welding portion of the base and the lid; and welding, second, the base and the lid at the unwelded portion such that the groove is closed.

A manufacturing method of an electronic device, that accommodates a gyro element as an electronic component in an inner space formed by a base and a lid as a lid body, includes: preparing the lid in which a groove is provided on the rear surface which is welded with the base, and an opening area of the groove on the inner space side which is greater than an opening area on the outer periphery side of the lid; welding, first, the base and the lid at a portion excluding an unwelded portion that includes at least apart of the groove, of a planned welding portion of the base and the lid; and welding, second, the base and the lid at the unwelded portion such that the groove is closed.

A sliding electric contact device for welding head for roller welding machines, having comprises a bimetallic plate adapted to be fixed to a shaft of a welding head, having a protection base composed of a first metal, defining a first face destined to abut against an end surface of the shaft, and a sliding disk composed of a second metal softer than the first metal, defining a second sliding electric contact face; a composite current-carrying block, having a plait of electrical wires, an internal support made of metal, pushed against the sliding disk for realizing with the sliding disk a sliding electric contact, first means adapted to fix firmly a central portion of the plait to the inner support, second current-carrying means adapted to fix firmly a peripheral portion of the plait to current terminals of a stator of the welding head. A welding head having the sliding electric contact device and a related roller welding machine are also disclosed.