Device for planing a sheet metal strip under tension

A device for planning a sheet metal strip under tension supplied from a source of metal strip that has been produced by milling, comprising only three working rolls comprising at least two small-diameter first and second working rolls between which the strip passes while being subjected to successive flexural deformation in opposite directions, and a third working roll located downstream in the direction of travel of the strip with respect to the first two rolls and positionally adjustable with respect to said first two rolls and at least two tensioning means respectively disposed upstream of said first two rolls and downstream of said third working roll for effecting said tension of the strip with the direction of feed being from said first working roll to said third working roll of said planning device, wherein the third working roll aforesaid is rotatably mounted on a support pivoted about a shaft of the first working roll with respect to the frame which carries the second working roll so as to provide means for adjusting the angle of winding of the metal strip on the second roll and for producing a third flexural deformation of the strip in a direction opposite to its deformation on the second roll with an amplitude which is a function of the relative position of said third roll with respect to said second roll.