A disk cutter bar (1), comprising a supporting frame (2), a plurality of knife supporting disks (3) which are associated with the frame (2) so that they can rotate about respective substantially parallel rotation axes (A), a gear transmission assembly (4) for the rotational actuation of the knife supporting disks (3), which comprises a series of idle gears (7) which move a plurality of pinions (8) for the rotational actuation each of a respective knife supporting disk (3), a pivot (9) for coupling to the corresponding knife supporting disk (3) that is associated with each one of the pinions (8), which is associated with the frame (2) by means of the interposition of rotational support means (10), has a first end (11) which is associated integrally with the corresponding pinion (8) and a second end (12) which is associated integrally with the disk and is provided with at least one shearing region (13) in an intermediate position between the ends, the pivot (9) being adapted to shear at the shearing region (13) following an overload of torque which acts thereon, forming a first portion (14) which comprises the first end (11) and a second portion (15) which comprises the second end (12), and retention means (16) associated with each one of the pivots (9) for the retention of the second portion (15) following the shearing of the pivot. The particularity of the invention resides in that the retention means (16) are associated with each one of the pivots (9) with axial play so as to allow the spacing in an axial direction of the second portion (15) with respect to the first portion (14) as a consequence of the shearing of the pivot, passing from an active configuration to a safety configuration of the corresponding knife supporting disk (3), and in that it comprises means (17) for the release of potential energy which are associated with each one of the pivots (9) and are adapted to activate as a consequence of the shearing of the pivot to space the second portion (15) from the first portion (14) and to keep the second portion in the safety configuration.