| 摘要 |
A door operator for opening and closing an upwardly acting door and including a power unit having reversible motor means for driving the operator. The motor means is associated with a control circuit which includes upper and lower limit switches actuated when the door is in the opened and closed positions, respectively, which limit switches are connected in parallel and control the reversing of the motor rotation. The circuit also includes a reversing switch for reversing the motor rotation and door movement automatically if the door engages an obstacle during movement in the closing direction. Control means are associated with the reversing switch for deactivating same when the door is positioned closely adjacent but slightly spaced from its fully closed position to prevent undesired reversing of the door. The control means also includes means for deactivating the reversing switch when the door is positioned closely adjacent but slightly spaced from its fully opened position. |
