Roller leveler and metal sheet flattening method

A roller leveler for flattening a metal sheet having a cut-sheet form, the roller leveler comprising:

• a leveling unit that includes a plurality of leveling rolls disposed in a staggered state on upper and lower sides of a pass line of the metal sheet to be flattened and configured to rotate to sandwich and flatten the metal sheet while passing the metal sheet therethrough, a hydraulic pressing cylinder configured to press the metal sheet via the leveling rolls, and a drive unit configured to rotate the leveling rolls to pass the metal sheet;
• a first pinch roll unit and a second pinch roll unit respectively disposed on opposite outsides of a leveling roll array area, in which the leveling rolls are disposed along the pass line of the metal sheet, each of the first and second pinch roll units including a pair of pinch rolls configured to pinch the metal sheet and apply a drawing force thereto;
• and
• a control system configured to control flattening of the metal sheet,
• wherein the control system is configured to perform control such that the metal sheet is passed through the leveling roll array area in a first direction oriented from the first pinch roll unit toward the second pinch roll unit, in a state where the metal sheet is not pressed or in a state where the metal sheet is pressed by the pressing cylinder with a pressing amount small enough to allow the metal sheet to be passed by the drive unit;
• then, when a leading end of the metal sheet reaches the second pinch roll unit, the pressing amount given by the pressing cylinder is increased to a value necessary for flattening the metal sheet, and a drawing force in the first direction is applied by the second pinch roll unit to the metal sheet to pass the metal sheet;
• then, when a tail end of the metal sheet has passed through the leveling roll array area, a feed direction of the metal sheet is changed from the first direction to a second direction opposite to the first direction;
• then the metal sheet is passed through the leveling roll array area in the second direction, in a state where the metal sheet is not pressed or in a state where the metal sheet is pressed by the pressing cylinder with a pressing amount small enough to allow the metal sheet to be passed by the drive unit;
• and then, when the tail end of the metal sheet reaches the first pinch roll unit, the pressing amount given by the pressing cylinder is increased to a value necessary for flattening the metal sheet, and a drawing force in the second direction is applied by the first pinch roll unit to the metal sheet to pass the metal sheet.

A roller leveler for flattening a metal sheet having a cut-sheet form, the roller leveler comprising:

• a leveling unit that includes a plurality of leveling rolls disposed in a staggered state on upper and lower sides of a pass line of the metal sheet to be flattened and configured to rotate to sandwich and flatten the metal sheet while passing the metal sheet therethrough, a hydraulic pressing cylinder configured to press the metal sheet via the leveling rolls, and a drive unit configured to rotate the leveling rolls to pass the metal sheet;
• a pinch roll unit disposed on one outside of a leveling roll array area, in which the leveling rolls are disposed along the pass line of the metal sheet, and including a pair of pinch rolls configured to pinch the metal sheet and apply a drawing force thereto;
• a metal sheet reversing mechanism disposed on the other outside of the leveling roll array area, and configured to turn the metal sheet to reverse positions of leading and tail ends thereof;
• and
• a control system configured to control flattening of the metal sheet,
• wherein the control system is configured to perform control such that the metal sheet is passed through the leveling roll array area from a metal sheet reversing mechanism-side of the leveling unit, in a state where the metal sheet is not pressed or in a state where the metal sheet is pressed by the pressing cylinder with a pressing amount small enough to allow the metal sheet to be passed by the drive unit;
• then, when a leading end of the metal sheet reaches the pinch roll unit, the pressing amount given by the pressing cylinder is increased to a value necessary for flattening the metal sheet, and a drawing force is applied by the pinch roll unit to the metal sheet to pass the metal sheet;
• then, when a tail end of the metal sheet has passed through the leveling roll array area, the metal sheet is transferred into the metal sheet reversing mechanism and the metal sheet is turned to reverse positions of the leading end and the tail end thereof;
• then, the metal sheet thus reversed is passed through the leveling roll array area from the metal sheet reversing mechanism-side, in a state where the metal sheet is not pressed or in a state where the metal sheet is pressed by the pressing cylinder with a pressing amount small enough to allow the metal sheet to be passed by the drive unit;
• and then, when the leading end of the metal sheet reaches the pinch roll unit, the pressing amount given by the pressing cylinder is increased to a value necessary for flattening the metal sheet, and a drawing force is applied by the pinch roll unit to the metal sheet to pass the metal sheet.

A roller leveler for flattening a metal sheet having a cut-sheet form, the roller leveler comprising:

• first and second leveling units arrayed along a pass direction of the metal sheet, and each including a plurality of leveling rolls disposed in a staggered state on upper and lower sides of a pass line of the metal sheet to be flattened and configured to rotate to sandwich and flatten the metal sheet while passing the metal sheet therethrough, a hydraulic pressing cylinder configured to press the metal sheet via the leveling rolls, and a drive unit configured to rotate the leveling rolls to pass the metal sheet;
• a pinch roll unit disposed between the first leveling unit and the second leveling unit, and including a pair of pinch rolls configured to pinch the metal sheet and apply a drawing force thereto;
• and
• a control system configured to control flattening of the metal sheet,
• wherein the control system is configured to perform control such that the second leveling unit is set in a state where the metal sheet is to be not pressed or in a state where the metal sheet is to be pressed by the pressing cylinder with a pressing amount small enough to allow the metal sheet to be passed by the drive unit;
• then the metal sheet is passed, toward the second leveling unit, through a first leveling roll array area of the first leveling unit, in which the leveling rolls are disposed, in a state where the metal sheet is not pressed or in a state where the metal sheet is pressed by the pressing cylinder with a pressing amount small enough to allow the metal sheet to be passed by the drive unit;
• then, when a leading end of the metal sheet reaches the pinch roll unit, the pressing amount given by the pressing cylinder of the first leveling unit is increased to a value necessary for flattening the metal sheet, and a drawing force is applied by the pinch roll unit to the metal sheet to pass the metal sheet;
• then, when a tail end of the metal sheet reaches the pinch roll unit, the first leveling unit is set in a state where the metal sheet is to be not pressed or in a state where the metal sheet is to be pressed by the pressing cylinder with a pressing amount small enough to allow the metal sheet to be passed by the drive unit;
• and then the pressing amount given by the pressing cylinder of the second leveling unit is increased to a value necessary for flattening the metal sheet, and a drawing force is applied by the pinch roll unit to the metal sheet to pass the metal sheet toward the first leveling unit.

A metal sheet flattening method of flattening a metal sheet having a cut-sheet form in a roller leveler, which includes

• a plurality of leveling rolls disposed in a staggered state on upper and lower sides of a pass line of the metal sheet to be flattened and configured to rotate to sandwich and flatten the metal sheet while passing the metal sheet therethrough,
• a hydraulic pressing cylinder configured to press the metal sheet via the leveling rolls,
• a drive unit configured to rotate the leveling rolls to pass the metal sheet, and
• a pinch roll unit disposed on one side of a leveling roll array area, in which the leveling rolls are disposed along the pass line of the metal sheet, and including a pair of pinch rolls configured to pinch the metal sheet and apply a drawing force thereto,
• the method comprising:
• causing the pressing cylinder to press the metal sheet by the pressing cylinder via the leveling rolls with a pressing amount necessary for flattening the metal sheet, while passing the metal sheet between the leveling rolls by a driving force applied by the drive unit and the drawing force applied by the pinch rolls.

A metal sheet flattening method of flattening a metal sheet having a cut-sheet form in a roller leveler, which includes

• a leveling unit that has a plurality of leveling rolls disposed in a staggered state on upper and lower sides of a pass line of the metal sheet to be flattened and configured to rotate to sandwich and flatten the metal sheet while passing the metal sheet therethrough, a hydraulic pressing cylinder configured to press the metal sheet via the leveling rolls, and a drive unit configured to rotate the leveling rolls to pass the metal sheet, and
• a first pinch roll unit and a second pinch roll unit respectively disposed on opposite outsides of a leveling roll array area, in which the leveling rolls are disposed along the pass line of the metal sheet, each of the first and second pinch roll units including a pair of pinch rolls configured to pinch the metal sheet and apply a drawing force thereto,
• the method comprising:
• passing the metal sheet through the leveling roll array area in a first direction oriented from the first pinch roll unit toward the second pinch roll unit, in a state where the metal sheet is not pressed or in a state where the metal sheet is pressed by the pressing cylinder with a pressing amount small enough to allow the metal sheet to be passed by the drive unit;
• then, when a leading end of the metal sheet reaches the second pinch roll unit, increasing the pressing amount given by the pressing cylinder to a value necessary for flattening the metal sheet, and applying a drawing force in the first direction by the second pinch roll unit to the metal sheet to pass the metal sheet;
• then, when a tail end of the metal sheet has passed through the leveling roll array area, changing a feed direction of the metal sheet from the first direction to a second direction opposite to the first direction;
• then passing the metal sheet through the leveling roll array area in the second direction, in a state where the metal sheet is not pressed or in a state where the metal sheet is pressed by the pressing cylinder with a pressing amount small enough to allow the metal sheet to be passed by the drive unit;
• and then, when the tail end of the metal sheet reaches the first pinch roll unit, increasing the pressing amount given by the pressing cylinder to a value necessary for flattening the metal sheet, and applying a drawing force in the second direction by the first pinch roll unit to the metal sheet to pass the metal sheet.

A metal sheet flattening method of flattening a metal sheet having a cut-sheet form in a roller leveler, which includes

• a leveling unit that has a plurality of leveling rolls disposed in a staggered state on upper and lower sides of a pass line of the metal sheet to be flattened and configured to rotate to sandwich and flatten the metal sheet while passing the metal sheet therethrough, a hydraulic pressing cylinder configured to press the metal sheet via the leveling rolls, and a drive unit configured to rotate the leveling rolls to pass the metal sheet,
• a pinch roll unit disposed on one outside of a leveling roll array area, in which the leveling rolls are disposed along the pass line of the metal sheet, and including a pair of pinch rolls configured to pinch the metal sheet and apply a drawing force thereto, and
• a metal sheet reversing mechanism disposed on the other outside of the leveling roll array area, and configured to turn the metal sheet to reverse positions of leading and tail ends thereof,
• the method comprising:
• passing the metal sheet through the leveling roll array area from a metal sheet reversing mechanism-side of the leveling unit, in a state where the metal sheet is not pressed or in a state where the metal sheet is pressed by the pressing cylinder with a pressing amount small enough to allow the metal sheet to be passed by the drive unit;
• then, when a leading end of the metal sheet reaches the pinch roll unit, increasing the pressing amount given by the pressing cylinder to a value necessary for flattening the metal sheet, and applying a drawing force by the pinch roll unit to the metal sheet to pass the metal sheet;
• then, when a tail end of the metal sheet has passed through the leveling roll array area, transferring the metal sheet into the metal sheet reversing mechanism and turning the metal sheet to reverse positions of the leading end and the tail end thereof;
• then, passing the metal sheet thus reversed through the leveling roll array area from the metal sheet reversing mechanism-side, in a state where the metal sheet is not pressed or in a state where the metal sheet is pressed by the pressing cylinder with a pressing amount small enough to allow the metal sheet to be passed by the drive unit;
• and then, when the leading end of the metal sheet reaches the pinch roll unit, increasing the pressing amount given by the pressing cylinder to a value necessary for flattening the metal sheet, and applying a drawing force by the pinch roll unit to the metal sheet to pass the metal sheet.

A metal sheet flattening method of flattening a metal sheet having a cut-sheet form in a roller leveler, which includes

• first and second leveling units arrayed along a pass direction of the metal sheet, and each having a plurality of leveling rolls disposed in a staggered state on upper and lower sides of a pass line of the metal sheet to be flattened and configured to rotate to sandwich and flatten the metal sheet while passing the metal sheet therethrough, a hydraulic pressing cylinder configured to press the metal sheet via the leveling rolls, and a drive unit configured to rotate the leveling rolls to pass the metal sheet, and
• a pinch roll unit disposed between the first leveling unit and the second leveling unit, and having a pair of pinch rolls configured to pinch the metal sheet and apply a drawing force thereto,
• the method comprising:
• setting the second leveling unit in a state where the metal sheet is to be not pressed or in a state where the metal sheet is to be pressed by the pressing cylinder with a pressing amount small enough to allow the metal sheet to be passed by the drive unit;
• then passing the metal sheet, toward the second leveling unit, through a first leveling roll array area of the first leveling unit, in which the leveling rolls are disposed, in a state where the metal sheet is not pressed or in a state where the metal sheet is pressed by the pressing cylinder with a pressing amount small enough to allow the metal sheet to be passed by the drive unit;
• then, when a leading end of the metal sheet reaches the pinch roll unit, increasing the pressing amount given by the pressing cylinder of the first leveling unit to a value necessary for flattening the metal sheet, and applying a drawing force by the pinch roll unit to the metal sheet to pass the metal sheet;
• then, when a tail end of the metal sheet reaches the pinch roll unit, setting the first leveling unit in a state where the metal sheet is to be not pressed or in a state where the metal sheet is to be pressed by the pressing cylinder with a pressing amount small enough to allow the metal sheet to be passed by the drive unit;
• and then increasing the pressing amount given by the pressing cylinder of the second leveling unit to a value necessary for flattening the metal sheet, and applying a drawing force by the pinch roll unit to the metal sheet to pass the metal sheet toward the first leveling unit.