886,301. Welding by fusion. TOOTH CO., H. & L. May 6, 1958, No. 14459/58. Class 83 (4). An arc welding machine, e.g. for billet welding along a rectangular path, has a reciprocatable work-holder, and a welding head rotatable about a vertical axis and reciprocatable relative to the work-holder and carrying a consumable electrode at an angle to the axis such that the weld point lies on the axis, the table and the welding head being moved in predetermined timed relationship to produce a weld along the desired path. The machine is used for welding digger teeth each comprising a cup 11, Figs. 26, 27, 30 and 33, and a base 14. A pair of teeth are oppositely positioned on a work support 25 so that a continuous weld can be made round them, the teeth being subsequently broken apart. Where as shown in Fig. 33 the teeth have projections 17a blocks 19 subsequently broken away are used to enable a continuous weld to be made. The bases 11 are held against a ridge 61 on the work support 25 by arms 64 and a cross-piece 63 of a retainer 26, the arms 64, cross-piece 63 and ridge 61 being shaped to retain flux in position over the weld. The work support 25 is fixed to a table 24 reciprocatable on rails 70, Fig. 6, extending from the front to the rear of the machine frame 20. The retainer 26 is mounted on the table 24 and can be retracted to enable the work to be placed on or removed from the support 25. The cups 11 are located by a holder G having a fixed plate 92 and a spring-loaded plate 93 gripping the vertical sides of the cups and projections 91 engaging the sloping face of the cups. A carriage 31 carried by the table 24 and reciprocatable in a slot in the table 24 carries a post 29 vertically movable in rollers 97 on the carriage 31 and supporting the gripper G. In a transversely reciprocatable carriage O, Figs. 1, 11 and 15, having rollers 141 running on rails 23 on the frame 20 is journalled a spindle N to the lower end of which is secured a bracket to which an arm 40 on the welding head Q is bolted. An arcuate slot in the arm 40 provides angular adjustment of the welding head Q about the welding point which lies on the axis of the spindle N. The spindle N is rotatable by 90 degrees at a time by a pawl 187 co-operating with projections 186 on the top of the spindle N, the pawl 187 being reciprocated when the weld reaches a corner of the weld path. All reciprocating movements of the machine are effected by fluid-pressure actuated pistons. Current for the electrode feed motor S and for the arc is supplied through brushes 352 engaging slip rings 351 on the spindle N. Flux is supplied from a hopper under control of an electromagnetically actuated valve V having a ballshaped closure member to a funnel at the upper end of a bore 140 passing through the spindle N and communicating with a flexible pipe 241 extending to a point adjacent the welding rod. The welding rod 35 is fed through a guide and contact device, Fig. 21, consisting of contact members 130 bolted to a plate 122 secured to an apertured guide 120. Slotted bolt holes in one of the contact members allow it to be pressed by a spring 139 into engagement with the electrode 35. The guide 120 terminates in a ridge 382, Fig. 43, bearing against a plate having a transverse ridge 386 bearing against a flat surface 385 on the main body of the welding head. Pairs of bolts 395, 396 secure the guide to the plate and the latter to the welding head and provide a universal adjustment for the electrode guide 120. The contact members 130 are provided with grooved wearing surfaces 135. After starting of the machine all operations are controlled automatically in a timed sequence to produce the complete weld, by movement of the table 24, the carriage O and rotation of the spindle N. In a modification the spindle N is rotated by a fluid motor under control of a valve closed by a cam when the spindle N has turned through 90 degrees. In a further modification the work support 25 forms part of a slide transversely reciprocatable on the table 24 so that work can be removed from and placed on one end of the slide while the work on the other end is being welded.