| 摘要 |
In counterbalance means for a sectional overhead door (1) safety means is provided to operate in the event of failure of a cable (5) of the counterbalance means, the safety means comprising a cam (17) biassed by a spring (22) into a position in which it will brake closing movement of the door, an arm (20) extending radially from a shaft (15) which mounts the cam (17), a gate lever (23) to secure the arm (20) and trip means in the form of a pin (26), coupled to the end of the cable (5), and a spring (10) whereby upon failure of the cable (5) the spring (10) removes the pin (26) to cause the spring (22) to move the cam (17) to effect braking of the closing movement of the door (1). <IMAGE> |
