Wire gripper for a drive unit of a wire feeder

A wire gripping device for a welding wire feeder, said gripping device comprising a first roller rotatable about a first axis and having a first radially extending peripheral edge coaxial with said first axis;

• a second roller rotatable about a second axis and having a second radially extending peripheral edge coaxial with said second axis, said first and second peripheral edges engaging the welding wire when in a drive position to drive the welding wire, said first roller being displaceable relative to said second roller;
• said wire gripping device further including an adjustable force producing device selectively engageable with said first roller thereby selectively urging said first roller toward said second roller, said force producing device generating a gripping force in a range of forces from a minimum force to a maximum force, said gripping force increasing non-linearly in said range.

A wire gripping device for a welding wire feeder, said gripping device comprising a first roller rotatable about a first axis and having a first radially extending peripheral edge coaxial with said first axis;

• a second roller rotatable about a second axis and having a second radially extending peripheral edge coaxial with said second axis, said first and second peripheral edges engaging the welding wire when in a drive position to drive the welding wire, said first roller being displaceable relative to said second roller through a range of displacement;
• said wire gripping device further including an adjustable force producing device for said displacement, said force producing device having a non-constant modulus through said range of displacement.

A wire gripping device for a welding wire feeder to produce a gripping force against the welding wire, said gripping device comprising a stationary roller mounted to said gripping device to allow rotation of said stationary roller about a stationary axis;

• an adjustable roller mounted to said gripping device to allow rotation of said adjustable roller about an adjustable axis;
• the wire passing between said adjustable roller and said stationary roller;
• and said gripping device further including an adjustment element to displace said adjustable roller relative to said stationary roller wherein said element displaces said adjustable roller over a range of displacement and produces said gripping force, at least of portion of said gripping force increasing at a non-linear rate as said adjustment element is displaced over said range of displacement.

A force producing device for generating a gripping force between at least a first and a second roller, said first roller and said second roller having a displacement therebetween, said force producing device comprising:

• a biasing member generating a continuous range of selectable gripping forces from a minimum force to a maximum force;
• wherein a ratio of the gripping force to displacement is non-linear between said minimum force and said maximum force.

A force producing device for generating a gripping force between at least a first and a second roller in a wire feeder, said force producing device comprising an adjuster for urging the first roller toward the second roller and a biasing member, said biasing member generating said gripping force as said adjuster urges the first roller toward the second roller, said biasing member producing a range of gripping forces from a minimum force to a maximum force, at least a portion of said gripping force increasing non-linearly between said minimum and said maximum.

A wire feeder having a force producing device for generating a gripping force between at least a first and a second roller and a welding wire, said force producing device comprising an adjuster for urging the first roller toward the second roller and a biasing member, said biasing member generating said gripping force as said adjuster urges the first roller toward the second roller and engages the welding wire, said biasing member producing a range of gripping forces from a minimum force to a maximum force, at least a portion of said gripping force increasing non-linearly between said minimum and said maximum.

A welding machine having a force producing device for generating a gripping force between at least a first and a second roller and a welding wire, said force producing device comprising an adjuster for urging the first roller toward the second roller and a biasing member, said biasing member generating said gripping force as said adjuster urges the first roller toward the second roller and engages the welding wire, said biasing member producing a range of gripping forces from a minimum force to a maximum force, at least a portion of said gripping force increasing non-linearly between said minimum and said maximum.