Patent ID: 7966771

Claim:
A door operator, comprising: a housing; an output shaft; a drive unit disposed in a drive unit compartment of the housing and configured to be coupled to a door via the output shaft, the drive unit comprising: a cam drive having a cam disc disposed on the output shaft; and two force transmission rollers disposed on opposite sides of a longitudinal axis of the output shaft that bear on cam paths of the cam disc; a motor, in driving connection with the drive unit; a spring force accumulator coupled to the motor and arranged in the housing and is connected to the drive unit; a hydraulic pump configured to be driven by the motor in hydraulic connection with a drive unit pressure compartment; at least one pressure compartment disposed adjacent to a spring tensioning piston associated with the spring force accumulator such that a division of pressure for opening the door and for tensioning the spring force accumulator occurs, wherein the pressures act in a direction of tension of the spring force accumulator; and a fluid-tight separating wall configured to separate the at least one pressure compartment from the drive unit pressure compartment.