Patent ID: 7718917

Claim:
A system adapted for welding a plurality of workpieces cooperatively defining a top outermost surface over a dual heating process, said system comprising: a resistance heating unit including first and second spaced electrodes configured to solely engage the top surface, wherein one of said electrodes is positively charged, said electrodes cooperatively present a voltage drop, and cooperatively cause a current flow to be produced within, and a first heat energy to engage the workpieces, when brought into contact with the surface, so as to heat a first portion of the workpieces to a temperature range above a minimum temperature for a heating period; and a welding device spaced from the unit, configured to subsequently engage the top surface and generate a second heat energy separate from the first, wherein the second energy is operable to further heat the first portion during the period, said unit and device being cooperatively configured to form a weld within said plurality of workpieces, such that the total heat energy that causes the formation of the weld is cooperatively produced by the unit and device.