Hydraulic cranes—whether referring to rough-terrain (RT), all-terrain (AT), or truck cranes, and the knuckleboom or telescoping boom variety—provide a wide range of capacities for almost any lifting job.
Although they have been around for many years, today's hydraulic cranes are different than those built just 10 years ago. One look at the controls of a typical rough-terrain crane shows how these machines have changed. Like many pieces of heavy equipment, these new machines are fitted with computers and other high-tech electronic components. The hydraulics are essentially the same, but this technological shift makes the machines easier to operate.
In the old hydraulic systems, every function had its own circuit; sometimes they had different hydraulic pumps as well. Usually this meant a separate control lever coming out of the floor for each function. Now those levers have been replaced by more modern-looking, electronic joysticks with multiple functions. The move to joystick controls has also dramatically improved the overall ergonomics, making it possible for almost anyone to operate a large crane.
This modernization has not only simplified the console, but onboard computers and software now provide finer control of the crane's operation and automatically limit the load based on weight and boom angle.
The trend toward computerization began some years back, says Brian Gibson, president of Capital City Cranes in Columbus, Ohio. Now, the cranes use fiber optic cables, sophisticated machine communications, load moment indicators, swing sensors, and other complex subsystems to control almost every aspect of the crane's operation
However, even though it has made it easier for operators, maintenance is more difficult. “Our mechanics go through extensive computer diagnostic training through the crane manufacturers,” Gibson says. Nowadays, a mechanic needs to know as much about software as hydraulics.
Although this has resulted in increased uptime and reliability, it doesn't really change how cranes are used. Other changes have a more direct effect on day-to-day operation.
In one such alteration, manufacturers are using lighter, stronger steel in the boom designs. This has led to increased capacity in some cases. The OEMs also are decreasing the overall weight of the machine for increased mobility and efficiency.
However, the lighter overall weight has affected the balance of the rig, particularly when reaching out with the boom. In some cases, cranes have increased capacity close in to, but decreased capacity farther away from, the machine.
One last change to consider with cranes doesn't really have to do with the cranes themselves. The regulations regarding working around cranes have become tougher over the years. For example, workers are no longer allowed to ride on the ball, and the use of man baskets is increasingly restricted, and should only be employed as a last resort.