An apparatus having a drive unit having a first drive axis rotatable about a first axis of rotation and a second drive axis rotatable about a second axis of rotation, the second drive axis being coaxial with and partially within the first drive axis and axially rotatable within the first drive axis. A robot arm has an upper arm connected to the drive unit at the first drive axis, a forearm coupled to the upper arm, the forearm being coupled to the upper arm at a first rotary joint and rotatable about the first rotary joint, the first rotary joint being actuatable by a first band arrangement coupled to the second drive axis, and an end effector coupled to the forearm, the end effector being coupled to the forearm at a second rotary joint and rotatable about the second rotary joint, the second rotary joint being actuatable by a second band arrangement coupled to the first rotary joint. The second band arrangement is configured to provide a variable transmission ratio.