Patent ID: 7026574
Filing Date: 2006-04-11
Classification: B23K

Abstract:
1. A wire gripping device for a welding wire feeder, said gripping device comprising: a support member, a first pinch roll mounted on said support member, a lever arm pivotally connected to said support member, and having a second pinch roll mounted thereon for pivotal displacement therewith toward said first pinch roll to grip a wire therebetween, and an adjustable spring device between said support member and said lever for biasing said second pinch roll toward said first pinch roll to produce a gripping force on a wire therebetween, said spring device including a first member, a second member displaceable toward and away from said first member along a stroke of said spring device, and a spring mechanism between said first and second members, said spring mechanism having at least a first and a second spring modulus for producing said gripping force as said first and second members are displaced toward one another along said stroke, said spring mechanism applying a first range of gripping forces along a first portion of said stroke with the force produced by said first spring modulus and a second range of gripping forces along a second portion of said stroke with force produced by said second spring modulus.