L68A1 Mast Section Safety supervision mechanism of tower crane
The main cause of many accidents is overload. The reason for overload is that the weight exceeds the requirements, and the horizontal distance of the weight exceeds the working radius. After the moment limiter is installed, when the moment exceeds the technical performance of the tower crane due to the overweight or excessive operation radius, the power source of lifting or luffing will be cut off automatically, and an alarm signal will be sent to prevent accidents.
At present, there are two kinds of moment limiters for tower crane: one is electronic, the other is mechanical. The electronic model can read the torque, working radius and weight data at the same time on the display. When approaching the allowable moment of the tower crane, there is an early warning signal, which is convenient to use, but it is greatly affected by the operation conditions, with poor reliability, easy to damage and inconvenient to maintain; the mechanical type has no display device and no early warning signal, but it works reliably, which is more suitable for the site construction operation conditions, with low single damage rate of the structure.
The moment limiter must be adjusted when the tower crane is reassembled in the conversion site, the conversion ratio and the boom length are changed. The electronic overload alarm point must also be calibrated with the actual operation radius and actual weight. When selecting mechanical moment limiter for trolley luffing tower crane, it must be suitable for the tower crane and the same factory type shall be selected.
