A mobile service technician equipped with a mechanics truck and service crane is a very efficient means to maximize uptime. But there are precautions the service technician should follow to ensure safe lifts.
"Today's crane service trucks have evolved along with the technology of the 21st century to become an important component of increased work site safety," says Kyle Whiteis, Auto Crane. "When a piece of equipment breaks or needs routine maintenance performed on it, having a service truck and crane on site not only gives workers the option of performing maintenance or repairs in the field or back at their facility, it allows crews to conduct that maintenance in a safer way.
"Whether that worker removes a track and works on it at the site or removes a transmission and takes it back to the shop to be fixed, he can often avoid crawling underneath or through areas that are inherently dangerous to him," he adds. "The operator can move heavier objects to a place that is more favorable for providing service, keeping the mechanic out of the way, yet still close to the job, so the equipment can get back into service faster."
However, to ensure safe lifts, service crane operation requires a knowledge of the crane, load charts and the weight of the object to be lifted.
Understand load charts
"Load charts and the weight of the [lifted] objects are the whole key to lifting safely," says Walt VanLaren, Service Trucks International, manufacturer of Tiger Cranes.
Make sure your technician understands and can read the chart. "We basically tell the owner that if the technician cannot figure out a load chart, he shouldn't be operating the crane," says Jason Ollerich, Feterl Mfg. "If you stay within the parameters of the load chart, it is pretty hard to get into any trouble."
Positioning of the crane and load does make a difference. "Cranes, outriggers and the truck work as a system to stabilize against the moment force of the object being lifted," says VanLaren. "Depending on where the crane is positioned in a rotational sense, there may be more or less ability for the body and chassis to counteract the force of the weight."
Of course, the load charts are useless if you don't know the weight of the load being lifted. Tim Worman, product manager for commercial vehicles, Iowa Mold Tooling (IMT), says one of the most common complaints the company receives is that the crane will not pick up an object that the technician thinks it should be able to handle. But when they investigate and weigh the load, it weighs more than the crane is designed to lift.
"Know the weight of what you are lifting and calculate the distance to the center line of the crane," advises Worman.
Most of today's cranes simply will not allow technicians to lift loads that are too heavy. "On the crane itself, there is an overload protection system," says Ollerich. "When the hydraulic pressure gets so high, it starts cutting out the functions that would allow you to keep increasing the load on the crane. Basically, it kicks out the electrical signal that actuates the valve. It is fool proof as long as you don't defeat the system."
Also make sure you have the appropriate amount of wire rope on the spool. "If you are doing a real heavy lift close to the truck, and you are using a lot of cable because you have your boom all the way out, keep the right number of wraps of cable on the drum so it stays attached," says Ollerich.
Use the outriggers
According to Worman, the stability of a service truck is measured with the outriggers deployed and compartments empty. Empty compartments represent a worst-case scenario; the truck will actually be more stable when it is filled with tools and other items that add weight. "But you should always use the outriggers to prevent tipovers," he adds.
Hydraulic outriggers are more likely to get used. "Ninety-nine percent of the trucks we build have hydraulic outriggers, so there is really no excuse not to use them," says Ollerich. "There is nothing wrong with a manual outrigger. It will work, it will function, it will support the load. But adding the power function to it just increases the likelihood that it is going to get used."