High conductive drive roll assembly for push-pull MIG torch

• Main Authors: MA TIEJUN, COSSETTE ROMEO N
• Format: Patent
• Language: English
• Published: 20.10.2015
• Subjects: CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR; PERFORMING OPERATIONS; SOLDERING OR UNSOLDERING; TRANSPORTING; WELDING; WORKING BY LASER BEAM

A drive roll assembly is disclosed for a push-pull MIG welding torch including a handle connected to a power cable assembly at one end, and a gooseneck-contact tip assembly at the other end. The drive roll assembly includes a body block disposed in the handle, a motorized driving gear mounted on the body block, and an idler wheel rotatably mounted on a mounting arm via a mount. The mounting arm is pivotally connected to the body block. The idler wheel is cooperable with the driving gear to pull welding wire from the cable assembly through the handle and towards the gooseneck. One of the idler wheel and the driving gear is made of a highly conductive material that allows for transfer of welding current to the welding wire, providing a secondary current transfer channel in addition to the conductive contact tip. The electric resistance from the body block to the surfaces of the idler wheel and driving gear at which they contact welding wire is below 15 milli-ohms, preferably below 2.0 milli-ohms.