BALER

A baler (1) for forming round bales of crops, includes: a frame (F) providing an internal volume; a compression chamber (C) for compressing the crops to form the bale; a plurality of belts (4) placed side by side in the internal volume; a tensioning system (6) having a pair of tensioning arms (601,602) associated with a pair of actuators (603,604) wherein the tensioning system is configured for adjusting the tension of the belts to a tensioning set point; wherein the tensioning system has a couple of fluid accumulators (A) having a gas volume, wherein the accumulators function responsive to the movement of the arms so that the gas expands when the tensioning arms are lowered and the actuator is shortened, and the gas is compressed when the actuator is elongated, and the arms are lifted.