| 摘要 |
A chain breakdown safety device for a power driven roller door, having a movable elongate rod with a rack thereon driven by a spring control, an idler attached to the rod for engagement with the chain, the idler being structured in a manner such that it will withdraw its engagement with the chain once the chain breaks, to permit a spring to displace the movable rod, causing the rack thereon to turn a gear which is provided with a ratcheted pawl, which engages the chain sprocket on the roller door drive winch in order to stop the door from falling, thereby protecting bystanders or equipment from injury or damage resulting from the breaking of the chain. |
