The subject matter described herein includes an upgraded planetary gearbox including an input support provided with an input transmission element axially rotatable and connectable to an external appliance, an output support provided with an output transmission element axially rotatable and connectable to an external appliance or to an external tool, at least one planetary wheelwork operationally placed between the input transmission element and the output transmission element, and a static coupling member between the planetary wheelwork and at least one of either the input support or the output support, wherein at least one of the static coupling member, the input support and the output support includes a measuring sensor for measuring the drive torque transmitted by the output transmission element.