Welding machine for the production of wire grid sheet

A welding machine, operating by the electric resistance welding method, for producing wire grid mat of longitudinal and transverse wires (L, Q) crossing one another and welded together at the crossing points, having a plurality of welding units (1, 1′), located transversely to the production direction, which at least for each longitudinal wire have one upper welding head (2) with an upper electrode, located above the grid production plane (X-X), and one lower welding head (5) along with a lower electrode movable counter to the upper electrode, the lower welding head being located below the grid production plane (X-X), having a common rail system (26, 28, 31) with at least two common rails extending along the welding line (S-S), for delivering the welding current to the welding electrodes, the common rails being electrically connectable to the two poles of at least one welding transformer (22, 22′), and having a conveying direction, which can be coupled to the welding electrodes (4, 7) for displacing and positioning the welding electrodes transversely to the production direction, characterized in that each upper welding head (2), with the aid of a connecting device (17, 18, 19, 20), can be firmly clamped to a stationary beam (13) extending parallel to the welding line (S-S) above the grid production plane (X-X), and each lower welding head (5), with the aid of a further connecting device (17′, 18′, 19′, 20′), can be firmly clamped to a stationary beam (14) extending parallel to the welding line (S-S) below the grid production plane (X-X);

• that for continuously variable positioning of all the welding units (1, 1′) transversely to the production direction (P1) along the welding line (S-S) of the welding machine, the upper welding head (2) of each welding unit (1, 1′) can be docked to an adjusting device (56), located above the grid production plane (X-X) and movable in a direction (P9) parallel to the welding line (S-S), with the aid of a clamping device (64, 65, 66), and the lower welding head (5) of the same welding unit (1, 1′) can simultaneously be docked to an adjusting device (57), located below the grid production plane (X-X) and movable (P9) parallel to the welding line (S-S), with the aid of a further clamping device (64′, 65′, 66′), and the two welding heads (2, 5) are detachable from their associated beams (13, 14);
• that the adjusting devices (56, 57), with the aid of a drive mechanism (60, 60′, 60″, 61, 62, 63) are movable (P9) in common and simultaneously parallel to the welding line (S-S);
• that the common rail system has one common rail (26, 28, 31) each extending above and below the grid production plane (X-X) parallel to the welding line (S-S) and extending over the machine width, and the upper electrodes (4) and the lower electrodes (7) are detachably connectable to the common rails (26;
• 28, 28a, 28b, 28c, 28d;
• 31, 31a, 31b, 31c, 31d);
• that the common rail of at least one pole has at least two common rails (28, 31) located parallel to one another and electrically insulated, and at least one common rail (28, 31) comprises at least two segments (28a, 28b, 28c, 28d;
• 31a, 31b, 31c, 31d), located one after the other along the welding line (S-S) and electrically insulated (29, 29′), and the insulators (29, 29′) between the segments (28a, 28b, 28c, 28d;
• 31a, 31b, 31c, 31d) of different common rails (28, 31) are offset from one another;
• that each segment (28a, 28b, 28c, 28d;
• 31a, 31b, 31c, 31d) is connectable to the pole of at least one welding transformer (22, 22′);
• and that for alternating connection of a welding electrode (4, 7) to the multiple common rails (28, 31), a displaceable (P6) switchover device (45) is provided.