Patent ID: 8601744

Claim:
A door operator comprising: a drive unit having a gear with a gear housing, the gear housing comprising: a flange element having a guide section, the guide section configured for at least one of bearing and supporting a gear member of a motor, the motor is mountable to the gear housing via the flange element; at least one first shell element; at least one second shell element configured to form: (a) an inner gear compartment when the first and the second shell elements are brought into mutual abutment, and (b) a reception tunnel in which the flange element is received via the guide section in a groove guide provided in the reception tunnel; at least one projection at a side of the guide section, the at least one projection facing one of the first and the second shell elements; at least one insert opening arranged in at least one of the first and the second shell elements corresponding to the at least one projection such that, when the at least one of the first and the second shell elements is placed onto the guide section, the at least one projection engages in the at least one insert opening; and a spring force accumulator received in a reception surface of the gear housing via a liner plate having a central opening, the liner plate being disposed between the spring force accumulator and the reception surface, wherein the reception surface is formed by the first and the second shell elements in the joined condition.