| 摘要 |
A mechanism (1) for opening and closing doors or gates comprises an input shaft connected to a motor, an output shaft (5) connected to the door or gate and a linking assembly. The linking assembly connects the input shaft, carrying worm (6), to the output shaft (5) to transmit movement. The linking assembly includes a selectively operable coupling, preferably a clutch, which has a replaceable friction regulator. Preferably the friction regulator is a replaceable component such as a flat washer or a curved spring plate (12, 20). In an engaged state the coupling transmits movement from the input shaft to the output shaft. The linking assembly also includes an adjustment means (18) for varying the coupling engaging force. The force required to manually override the coupling and open the door is established by varying or setting the adjustment means which are readily accessible. |
