1. A device should be installed. When the gondola encounters an obstacle, the device should stop the gondola from descending.
2. If there is a protruding structure above the gondola causing potential danger, an anti-collision bar device or other device at the top of the window cleaner should be installed.
3. Lifting and lowering limit switches
4. The lifting limit switch should be installed and correctly positioned. The gondola will automatically stop ascending when it is at the highest position; the lifting movement of the window cleaner should stop before contacting the terminal limit lifting limit switch. The lifting limit switch is in the equipment control system to prevent or allow the suspension device to turn, walk, pitch, and extend and retract the boom.
5. The descent limit switch should be installed and correctly positioned. When the gondola is at the lowest position, it will automatically stop descent; if the lowest position is the ground or a safety level, the anti-collision bar device can be regarded as a descent limit switch. In the lowest position, the gondola should stop before the limit switch at the end of the wire rope contacts (see 8.3.7).
6. The terminal hoist limit switch should be installed and correctly positioned, and the gondola will stop completely before reaching the limit position of the suspension wire rope. After its trigger, unless a qualified person takes corrective action, the gondola cannot rise and fall.
7. The lifting limit switch and terminal limit limit switch of the window cleaner shall have their own independent control devices.