摘要 |
A first force-measuring element (19) is arranged in the motor housing (48) of the motor drive for the door. The force-measuring element (19) is subjected to a force fM which corresponds to part of the swing moment between the support plate (45) and the motor housing (48). A second force-measuring element (26) is arranged in the door (44), and wires (60) lead from it to a circuitboard (61), to which the first force-measuring element (19) is also connected. The second force-measuring element (26) is exposed to the air-pressure difference between the inside of the door and the outside of the door. When the door is pushed open, the signals emitted by the two force-measuring elements are compared and the motor drive is put into operation. This ensures that the door cannot be opened by wind force, but can nevertheless be pushed open easily. <IMAGE> |