US Patent 9089887 Line threading device and method

An improved method for processing coiled metal sheet is provided, wherein a line threading device is inserted between the metal sheet and the process line surface at the leading edge of the metal sheet. The device is rigid and adapted to glide easily along the process line surface when propelled in a forward direction. The device has an upper surface that includes a plurality of grooves that run perpendicular to the forward direction, and the leading edge of the sheet, when it curves toward the process line surface, does not come into contact with a recess of the process line surface, but instead becomes lodged in a groove of the device, which guides the sheet along the process line surface, and does not impede forward progress.