Patent ID: 8721817

Claim:
A vibration welding method for welding first and second workpieces by effecting linear reciprocating movement of the first workpiece relative to the second workpiece while urging the workpieces together, said method comprising mounting a first workpiece support for linear reciprocating movement relative to a second workpiece support, effecting linear reciprocating movement of said first workpiece support with a pair of electromagnets coupled to said first workpiece support, each of said electromagnets including a drive coil and successively energizing and de-energizing said electromagnets out of phase with each other to effect said linear reciprocating movement of said first workpiece support by controllably coupling a source of DC current to, and de-coupling said source from, each of said electromagnets, producing signals representing the currents supplied to said electromagnets, and using said signals representing said currents to control the energizing and de-energizing of said electromagnets to effect linear reciprocating movement of said first workpiece support.