The cutting mechanism (30) has a curvilinear box (32) for receiving cutting disks (34-1-34-4) e.g. saw, actuators (36) and driving units (38) e.g. driving pulley, for rotationally driving the disks. Virtual center of the mechanism is on the rear of the box so as to present a convex leading edge (BA) in a work and forward direction (F). The cutting disks have rotating shafts placed along a curved line. The actuators are positioned at the back of the shafts of the disks. A monolithic frame (40) in the form of rigid base plate supports all forces, and a crankcase (42) is connected on the plate.