Jig for welding wheel rim blanks - where single loop induction coil provides welding current

摘要

Jig for seam welding a wheel rim blank or similar object with a high frequency welding current of several kHz min, fed through an induction loop which only passes once round the joint surfaces to form a gap in which the latter are located. Each long side of the gap has a bar (a) carrying most of the current and made of material with good electrical conductivity; and each bar is fixed on a back-up rail (b) made of material with poor conductivity and contg. 1 coolant channel. The loop forms a gap with larger width at the ends than in the middle so a uniform tep. is obtd. for welding, and the loop pref. provides the optimum compromise between high magnetic field in the blank and min. opposed inductive influences in the long sides of the loop. Provides optimum welding of wheel rim blanks using e.g. 150 kW power.