Before we go any further on mobile crane stability, we need to look at the mobile crane itself. Pulling it apart and looking at how the crane is constructed gives us a different perspective on balance than looking at the machine as a whole. So, lets de-construct it.

There are three basic components of the crane: superstructure, carrier and boom. Each one of these has a center of gravity (CG) and each of the components will affect the center of gravity of the combined parts in the final crane assembly.

The superstructure, upperstructure or upperworks, is the revolving frame of equipment on which the operating machinery are mounted along with the operator’s cab. The superstructure typically supports the crane’s counterweight on the rear and the boom or other attachment on the front. The CG of the superstructure will remain the same relative position regardless how the crane is positioned. (more…)

In Part 1 we took a high-level look at mobile crane stability, now its time to bring it back to the basics.

A mobile crane is built around the design principals of balance and leverage. In short, a crane must be capable of lifting heavy loads, through the use of leverage, while remaining in balance.

Before we dig into these concepts, we need to talk about gravity. We know from Newton and Einstein that the natural phenomenon of gravity is alive and well, all you have to do is drop a small object on your foot to be a believer. In material handling, we have to consider the Center of Gravity (or CG) of a load. The “center of gravity symbol”, illustrated by the black and white circles on the illustrations below is used to show the location where an object’s CG lies. The CG of any object is said to be the point in the object where the weight is evenly distributed. Meaning the leverage on one side of the object must be equal to the leverage derived by the other side of the object.

Now let’s look at a balance beam, which is similar to a basic crane model. (more…)

Safety training in the crane, rigging and specialized transportation sector is an ongoing process that is constantly evolving. Trends develop into standards and then standards change. American Cranes & Transport asked six training experts to identify the trends they are seeing in today’s training environment.  We asked them to cover simulators, demographics, most popular courses and certifications, recertification, hands-on training, training challenges and the most effective training methods.  Here’s what they had to say:

Industry Experts Reveal Training Trends

Of all crane-related accidents, tipping accidents are the most common. Crane operators who fail to follow the manufacturer’s guidelines regarding crane ratings are sure to suffer a tipping incident sooner or later. Possibly you have experienced a tipping incident where you felt the crane come up behind you (such as the feeling in the seat of the pants). Maybe you have had someone tell you that you had lifted one or more of the outriggers behind the crane or maybe you have been less fortunate, and your crane has turned over, changing the incident into an accident. In each of these cases, a loss of crane stability has come into play. (more…)

When we educate new mobile crane operators, one of the many topics we cover is the importance of lifting from directly above the load’s center of gravity.  However, it’s easy to forget until something goes wrong.

So why does this sheave look like this?

In the case of this sheave, which was taken from a rough terrain telescopic boom crane, it shows severe damage not just to the flange of the sheave, but to the outside of the sheave as well. Not only did the operator side pull the load crane once or just a little bit, the operator had to side pull (more…)