Sheet-processing machine comprising a turning device with a sheet-guiding drum, and method for adjusting the format of a sheet-guiding drum

A sheet-processing machine comprising a turning device with a sheet-guiding drum (2), wherein the sheet-guiding drum (2) has at least one gripper system (6) for securing the leading edge of a sheet, and

• wherein the sheet-guiding drum (2) has at least three casing segments (8, 9) that cooperate in the circumferential direction of the sheet-guiding drum (2) and engage with one another during format adjustment,
• wherein a leading casing segment (8), a trailing casing segment (9) and a middle casing segment are arranged in the circumferential direction of the sheet-guiding drum (2),
• wherein the middle casing segment has at least one sheet-supporting surface, which is located immediately adjacent to a sheet-supporting surface of the casing segment (8) that supports the leading portion of a sheet, and immediately adjacent to a sheet-supporting surface of the casing segment (9) that supports the trailing portion of a sheet, and
• wherein the middle casing segment comprises bridging elements (10) that include the sheet-supporting surfaces, and at least one bridging element (10) is arranged in the axial direction of the sheet-guiding drum (2) with its lateral face adjacent to a lateral face of a segment tooth of the leading casing segment (8) that supports the leading portion of a sheet, and with its opposing lateral face immediately adjacent to a lateral face of a segment tooth of the trailing casing segment (9) that supports the trailing portion of a sheet.