Double-point welding machine

Double-spot welding machine for producing wire grids formed of longitudinal wires (L) and cross wires (Q.sub.1, Q.sub.2), crossing each other at right angles, having

• a welding apparatus including
• two top electrode and bottom electrode pairs (2, 3;
• 2', 3') the top and bottom electrode pairs defining welding lines (S.sub.1, S.sub.2) which are spaced from each other by a predetermined distance in the direction of the longitudinal wires (L) and extend transversely to said direction,
• wherein one electrode (2, 2') of the pair is movable (P.sub.2) relative to the other (3, 3');
• a longitudinal wire feeding means (5, 6, 7, 8) for feeding a plurality of longitudinal wires (L) in a feeding direction longitudinally of the extent of the longitudinal wires;
• a cross-wire feeding means (9) for feeding two cross-wires in a direction transversely to said longitudinal direction and defining two insertion lines (E.sub.1, E.sub.2) spaced by a defined distance from each other, said insertion lines being located, with respect to said longitudinal wire feeding direction, in advance of the welding lines (S.sub.1, S.sub.2);
• a cross-wire transfer apparatus (10) for transferring the cross-wires from the insertion line (E.sub.1, E.sub.2) to the welding line (S.sub.1, S.sub.2) including
• a common support beam (11);
• a plurality of cross-wire support arms (12) supported on said common support beam (11), said cross-wire support arms (12) being formed with recesses (13) spaced by said defined distance for reception of the cross wires (Q.sub.1, Q.sub.2);
• said common support beam (11) being movable cyclically (P.sub.5) backwardly and forwardly in said longitudinal direction;
• a control device (C) controlling movement (P.sub.2) of one electrode of each pair with respect to the other,
• further controlling feeding movement (P.sub.3) of the longitudinal wire feeding means, and
• further controlling cyclical movement (P.sub.5) of said support beam (11);
• and wherein said movement of the longitudinal wire feeding means (5, 6, 7, 8), under control of said control device (C), places the longitudinal wires (L) in position at the welding lines and simultaneously pushes welded grid out of position from the welding lines;
• said control device further controlling duration of movement as well as speed of movement (v.sub.1 (T)) of the support beam (11) and duration of feeding movement as well as speed of feeding movement (v(R)) of the longitudinal wire feeding means,
• wherein the speed of movement (v.sub.1 (T)) of the support beam and the speed of feeding movement (v(R)) of the longitudinal wire feeding means are individually selectable, and
• the duration of movement of the support beam (t(T)) is longer than the duration of feeding movement (t(R)) of the longitudinal wire feeding means;
• and
• wherein holding means (15, 18) are provided for engaging the cross-wires (Q.sub.1, Q.sub.2) during transfer from the insertion lines (E.sub.1, E.sub.2) to the welding lines (S.sub.1, S.sub.2) and holding said cross-wires in said recesses (13) of the support arms (12) upon movement of the cross-wire support arms (12) secured to the common support beam (11).