Crane Safety Devices – Part 2

Continuing from part 1…

Anti-Upset Devices

With the increase in number of public and private construction project, there is a significant increase in the crane sales which feature many safety devices. Anti-upset devices are some of the most efficient safety devices that many crane for sale models include, as they prevent tipping-over and over-turning of the cranes. This means that the anti-upset devices protect cranes from chassis failure. The difference between the tipping load and the rated capacity of each crane for sale is usually up to 25 percent, depending on the type of crane. The rate of crane upset is once in 5 years, if used as a full-time machine, or once per every 10,000 working hours. Almost 80 percent of crane upsets have occurred due to operators’ error. About 5 percent have resulted in deaths and 9 percent in serious injuries. The anti-upset devices include boom angle indicators, levels, monitors, load-moment indicators, boom stops, anti-two-blocking mechanisms and wind sensors, which all improve the overall stability of the crane.


The cabin of each crane for sale needs to be equipped with levels for a better control over the crane. The levels are also known for reducing the possibility of side pull forces on the boom. Speaking of the boom, every mobile crane includes a boom angle indicator as a standard feature, although they are not so reliable. The boom angle indicator reads the angle at the boom base with a maximum of 2 degree error.

There are many cases in which the boom is raised to an angle that allows the lifted load to get into the underside of the boom. In such situation, the structure of the boom will certainly be compromised and the load may be dropped. Today, almost every boom crane for sale has a boom stops which prevent such situation. The boom blocks actively prevent the boom to move over the recommended angle. Usually, a boom block system involves the use of energy-absorbing or hydraulic shocks to stabilize the movement of the boom.

As cranes are usually very high, especially the tower cranes, they are vulnerable to stronger winds and may even break down. Wind sensors are very useful devices, as they allow a real-time monitoring of the weather conditions. When a tower crane is not in use, rotation brakes should be set in low minds configuration. But when winds reach a critical level of speed, cranes should reduce the amount of torque applied to the tower. The rotating breaks prevent a boom rotation and can stop a loaded boom.

Anti-two-blocking devices prevent the lower load block to get in contact with the upper load block. The anti-two-blocking devices may not be considered as anti-upset devices, but because they prevent boom failures or serious damages, it can be said that they provide an anti-upset protection.

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