Abstract: A shaft assembly for a protective or closing device comprises a hollow-shaped hollow section body and a drive unit. The shaft assembly is arranged to be mounted between a first support bearing and a second support bearing. The hollow section body is rotatable about longitudinal axis thereof and arranged to accommodate a curtain or a panel. The drive unit is at least partially accommodated in the hollow section body. The drive unit comprises an output for rotatably driving the hollow section body. The hollow section body comprises a first end and a second end and extends between the first support bearing and the second support bearing. At least at the first end or at the second end of the hollow section body, a connecting sleeve is provided. A biasing element is arranged between the hollow section body and the connecting sleeve. The connecting sleeve is axially displaceable relative to the hollow section body against a force applied by the biasing element.