Not long ago, if a crew had to go out and string a cable on miles of poles, and even had to put the poles in the ground, it meant a lot of heavy-duty grunt work. Dig the holes, muscle the poles off the carrier, insert them in the holes, push them upright, then climb up to string the cables. This practice is uncomfortable at best, highly dangerous at worst.
Other types of “high-up” jobs were just as bad. Trimming the tops of trees to keep them from weighing on power or communication lines, hanging banners from street lights, repairing power lines, and building communication antennas all required climbing ability on the part of technicians who faced considerable danger of falling, electrocution, and other life-threatening issues.
Today, these types of jobs are much easier. In fact, for anything that requires an operator or a technician to get up high, a truck can be equipped with a crane or a lift to make the job easier and safer.
Two Equipment Types Available
Both lift and crane devices are self-contained machines and truck-mounted units. Self-contained units are carried to the job site on a truck, and once off-loaded can be motored slowly around the site to reach specific work locations. The lift devices, sometimes called bucket trucks, are units that lift people directly to where the work is done. Crane devices lift objects that need to be worked on. Whether truck-mounted or self-contained, the devices are similar, differing mainly in what is on the end of the lift boom — either a lifting tackle or a work platform.
Depending upon its size, a lifting device can be installed on almost any size truck from a pickup or van to a dedicated heavy-duty flatbed. The size of the carrying vehicle is determined by the length of reach of the boom and the amount of overall weight the boom will have to carry.
With devices designed for everything from six-foot to 150-foot extensions, many choices are made before settling on the lift device or crane right for the jobs you have to do.
The smallest units are designed to fit onto the rear of a service body on a pickup chassis or onto the rear of a fullsize van. They increase in size to units that require a tandem-axle or even triple-axle rig to carry them. In both crane and bucket types, units are categorized by the lift distance, extension distance, and the load that can be hung from the end of the boom.
An offshoot is the tire service truck, which has a small crane on a service body to allow technicians to hoist and move the heavy wheels and tires found on over-the-road trucks and construction machinery. These differ from others in that the crane does not have a high lift, and it is usually installed at the front of the service body rather than the rear.
Booms Do Actual Lifting
Several types of booms do the actual lifting. Most cranes and lifts have a straight boom mounted on a swivel base. However, some feature a jib, or articulated boom, that can be extended from the main boom to reach closer into the work area.
Booms can be raised and extended by hydraulic rams or electric motordriven cables. For use in hazardous environments, such as near high-voltage electrical lines, insulated units are available. Otherwise, manufacturers say that un-insulated booms should not be used within 30 feet of a high-voltage electrical source.
Originally posted on Work Truck Online