A turning device in a sheet-processing machine includes a sheet-guiding drum. The sheet-guiding drum has at least one gripper system for securing a front edge of a sheet. The sheet-guiding drum also has at least three casing segments cooperating in the circumferential direction and engaging with one another during format adjustment. A method for the format adjustment of a sheet-guiding drum is also disclosed. The object of the invention is to further improve the sheet guiding on format-adjustable sheet-guiding drums in sheet-processing machines. This is achieved in that a middle casing segment in the circumferential direction has a drive.

A turning device in a sheet-processing machine includes a sheet-guiding drum. The sheet-guiding drum has at least one gripper system for securing a front edge of a sheet. The sheet-guiding drum also has at least three casing segments cooperating in the circumferential direction and engaging with one another during format adjustment. A method for the format adjustment of a sheet-guiding drum is also disclosed. The object of the invention is to further improve the sheet guiding on format-adjustable sheet-guiding drums in sheet-processing machines. This is achieved in that a middle casing segment in the circumferential direction has a drive.