Apparatus and method for bending glass sheets

A method for bending a glass sheet, comprising the steps of:

• (a) disposing in a furnace at least one hearth bed to convey the glass sheet in a first direction toward an outlet opening of the furnace over a top surface of the at least one hearth bed;
• (b) disposing in the furnace a final hearth bed at a position between the at least one hearth bed and the outlet opening of the furnace, the final hearth bed having a top surface for conveying the glass sheet toward the outlet opening of the furnace while bending the glass sheet to have a curved shape in conformity with the top surface, the final hearth bed having a bottom surface and an axis that is arranged along the bottom surface and toward the outlet opening of the furnace, the top surface being upwardly convexly curved to have a curvature defined along a plane that is perpendicular to the axis, the top surface having, in terms of stream of the glass sheet in the furnace, (1) an upstream end, (2) a downstream end that is at a level lower than that of the upstream end, and (3) an intermediate point defined between the upstream and downstream ends, the top surface having (i) a first section that extends from the upstream end to the intermediate point and that is parallel with the axis or upwardly inclined relative to the axis and (ii) a second section that extends from the intermediate point to the downstream end and that is downwardly inclined relative to the axis;
• (c) arranging the final hearth bed such that the bottom surface of the final hearth bed is along the first direction or inclined downwardly relative to the first direction;
• (d) conveying the glass sheet toward the outlet opening of the furnace over the at least one hearth bed and the final hearth bed;
• and
• (e) heating the glass sheet during the step (d), thereby bending the glass sheet to have a compound curvature in conformity with the top surface of the final hearth bed.

A method for bending a glass sheet, comprising the steps of:

• (a) disposing in a furnace at least one hearth bed to convey the glass sheet in a first direction toward an outlet opening of the furnace over a top surface of the at least one hearth bed;
• (b) disposing in a furnace a final hearth bed at a position between the at least one hearth bed and the outlet opening of the furnace,
• the final hearth bed having a top surface for conveying the glass sheet toward the outlet opening of the furnace while bending the glass sheet to have a curved shape in conformity with the top surface,
• the final hearth bed having an axis that is arranged toward the outlet opening of the furnace,
• the top surface of the final hearth bed being upwardly convexly curved to have a first curvature defined along the axis and a second curvature along a plane that is perpendicular to the axis,
• the top surface of the final hearth bed having, in terms of stream of the glass sheet in the furnace, upstream and downstream ends;
• (c) arranging the final hearth bed on a bed support to downwardly incline the final hearth bed relative to the first direction such that the downstream end of the final hearth bed is at a level lower than that of the upstream end of the final hearth bed and such that an intermediate apex of the final hearth bed is at a level higher than that of the upstream end of the final hearth bed, the intermediate apex being defined on the top surface of the final hearth bed and defined between the upstream and downstream ends in terms of stream of the glass sheet, when the final hearth bed is downwardly inclined by the step (c);
• (d) conveying the glass sheet toward the outlet opening of the furnace over the at least one hearth bed and the final hearth bed;
• (e) heating the glass sheet during the step (d), thereby bending the glass sheet to have a compound curvature in conformity with the top surface of the final hearth bed;
• (f) arranging a quenching unit for quenching the glass sheet at a position downstream of the final hearth bed;
• and
• (g) arranging a curved surface of the quenching unit relative to the top surface of the final hearth bed such that a first tangent to an upstream end portion of the curved surface of the quenching unit is superposed on a second tangent to a downstream end portion of the top surface of the final hearth bed or is upwardly or downwardly inclined to have an angle (α) to the second tangent.

An apparatus for bending a glass sheet, said apparatus comprising:

• (a) a furnace for heating the glass sheet, the furnace having an outlet opening for discharging the glass sheet;
• (b) at least one hearth bed housed in the furnace, for conveying the glass sheet in a first direction toward the outlet opening of the furnace;
• (c) a final hearth bed housed in the furnace at a position between the at least one hearth bed and the outlet opening of the furnace,
• the final hearth bed having a top surface for conveying the glass sheet toward the outlet opening of the furnace while bending the glass sheet to have a curved shape in conformity with the top surface,
• the final hearth bed having an axis that is arranged toward the outlet opening of the furnace,
• the top surface of the final hearth bed being upwardly convexly curved to have a first curvature defined along the axis and a second curvature along a plane that is perpendicular to the axis,
• the top surface of the final hearth bed having, in terms of stream of the glass sheet in the furnace, upstream and downstream ends,
• the final hearth bed being in an arrangement on a bed support to downwardly incline the final hearth bed relative to the first direction such that the downstream end of the final hearth bed is at a level lower than that of the upstream end of the final hearth bed and such that an intermediate apex of the final hearth bed is at a level higher than that of the upstream end of the final hearth bed, the intermediate apex being defined on the top surface of the final hearth bed and defined between the upstream and downstream ends in terms of stream of the glass sheet, when the final hearth bed is in the arrangement;
• and
• (d) a quenching unit for quenching the glass sheet, the quenching unit being arranged at a position downstream of the final hearth bed and having a curved surface for conveying the glass sheet,
• the curved surface of the quenching unit being arranged relative to the top surface of the final hearth bed such that a first tangent to an upstream end portion of the curved surface of the quenching unit is superposed on a second tangent to a downstream end portion of the top surface of the final hearth bed or is upwardly or downwardly inclined to have an angle (α) to the second tangent.