Clamping device with adjusting mechanism and method for adjusting the torque of the chuck

The invention relates to a tensioning device for a traction mechanism drive, comprising: a base body (3); at least one on the base body (3) clamping arm about a pivot axis (A4, 15) pivotally mounted (4, 5) with a tensioning roller (5, 6) on a bearing support (17) of the tensioning arm (4, 5) is rotatably mounted; Spring means (8) for resiliently urging the clamp arm (4, 5), wherein the spring means (8) between a first spring support (9) of the first clamp arm (4) and a second spring support (10) of the clamping device over a circumferential length (L8) extend about the pivot axis (A4, A6); an adjusting mechanism (11) for adjusting the first spring support (9) relative to the bearing support (17) of the tension roller (5) in the circumferential direction about the pivot axis (A4, A6). The invention further relates to a method for adjusting the torque of the chuck (2).