Getting a lift from cranes
Overhead cranes have the materials handling muscle to move loads weighing hundreds of tons as easily as 20 lb boxes.
By Tom Feare -- Modern Materials Handling, 3/1/2000
Need to move, raise, and lower loads? Cranes can take on these tasks and give your operation a big lift. No matter how large the job or small the load, cranes enhance productivity. They also reduce risks of employee injuries and eliminate many workplace safety problems.Cranes provide the materials handling muscle to move loads weighing hundreds of tons easily and precisely. They are just as suitable for lifting boxes weighing as little as 20 lbs. all day long. They do so without developing a backache. And without calling in sick the next day!
There's a wide range of crane designs and capacities to fit a variety of handling needs. Cranes satisfy the requirements of heavy production and process industries. They also meet the needs of far lighter duty assembly operations. They serve in warehousing and distribution applications as well.
With the many and varied applications of overhead cranes, the business is big: about $550 million in shipments annually. Indeed, the magnitude of the industry's sales figures belies any misperception that heavy industry plants using overhead cranes have all gone overseas. The long-familiar image of an overhead crane moving and helping pour molten metal in Smokestack America still is a valid one.
Even so, the numbers of new installations of the very large overhead cranes appear to be dwindling. "There are more growth opportunities for our industry in modernizations," suggests Peter Kerrick, vice president, Morris Material Handling, "than in providing original equipment." Morris is a major supplier of large cranes.That observation is "very true," says Bob Heyl, vice president of sales for Shepard Niles, also a major supplier of heavy-duty overhead cranes. The numbers of greenfield installations "is down significantly," he adds. In contrast, users "want to hang onto their old crane systems as long as possible." Shepard Niles gets requests, for example, "to fix a 30-year old system. We go in and make it last for another 30 years," he says. Primary metal producers are among those seeking modernizations.
In small workstation crane-the systems that handle light loads of a few hundred pounds or less-the numbers of new installations are soaring, however, manufacturers say.
One reason is that payloads handled in today's workstations are getting ever lighter, observes George Nolan, vice president and COO, Spanco. That trend builds new business. "Workstation cranes are installed today where years ago you had a man manually moving a 50 lb. load," he says.
Smaller loads also offer handling opportunities for jib cranes and gantry cranes. But what's really taken off are installations of enclosed track workstation cranes.
"Two years ago workstation cranes were our third best selling product line," reports Nolan, "behind jib cranes and gantry cranes. Now the workstation cranes are number one." For the last eight years this business "has been growing geometrically," he adds.
Demand for large overhead cranes in new installations isn't what it once was. From time to time, however, certain industries such as steel and its distribution network do want new, heavy-duty cranes. Meanwhile, orders for modernizations of old cranes for very heavy loads runs solid for some firms.
"There are lots of opportunities," says Mike Carlson, product manager for standard overhead cranes, Mannesmann Dematic. "Steel service centers, for example, need overhead cranes," he adds.
"Three to four years ago there was a push from the steel mills for the industry to provide cranes for casting and charging operations," he says. "Now we're seeing the downstream effects in crane demand from the steel service centers," Carlson says.
But steelmaking isn't what it once was in the U.S. "Today's mini-mills typically don't use cranes of the types and sizes that big steel once did," observes Shepard Niles' Heyl. Similarly, foundries still need crane handling; that business "is alive and well," he adds, though also not as strong as it once was.
Fabrication shops working with steel also have seen the need to install new, AC-motor-driven overhead cranes as replacements for older, DC-motor-powered units. LTV Steel in Cleveland is one example of this kind of business.
Industries that handle bulk materials other than metals are also major users of the equipment in the U.S. "Cranes for these overhead handling businesses tend to be fully automated in Europe," explains Dave Sinkhorn, product manager for process and engineered cranes, Mannesmann Dematic. But in the U.S. these users haven't chosen to automate their cranes. The result, says Sinkhorn, "is that you have a U.S. crane operator riding in a cab who is idle 20% to 30% of the time."
Indeed, there's an "increasing focus on automation of overhead cranes," notes Morris v.p. Kerrick. The aim is "to take some or perhaps all of the control of the crane out of an operator's hands." Cranes now are smarter, too, in terms of onboard diagnostics for preventative maintenance, he adds.
Kerrick also sees business "coming alive" in certain other end-user industry sectors as well. With raw material prices up for lumber and paper producers and copper mining firms, for example, these companies can afford to make capital spending investments in cranes, he says. Shipbuilding represents another opportunity.
Manufacturers of prefab metal buildings and the makers of tools and dies are among other users considering overhead crane installations, say the Mannesmann Dematic execs. Automating the stacking of large paper rolls for storage purposes is yet another prospective application.
Buy new or modernize?
Given the sizeable investment required in any large overhead crane system, end users are encouraged to consider upgrading their old cranes before jumping to a decision to buy new units. Retrofits with current technology can make old cranes perform well in new applications and in heavier duty usage.
"Modernization is a very viable opportunity for many customers," says Morris v.p. Kerrick. "More often than not, we can salvage an old crane up to a point." Up to an expense of about 70% of the cost of a new system, it generally makes sense to modernize, he adds.
Crane drive systems and controls represent key areas in which old cranes can achieve greater efficiencies with modernization. Switching from DC to AC power and to new controls can save on energy consumption. Adding the latest technology in variable frequency drives "can give users more opportunities to do more with their cranes," suggests Mannesmann's Carlson. Crane travel speed becomes more flexible and a similar degree of flexibility can be added to hoisting speed, he explains.
Morris exec Kerrick says that "continual improvements in solid-state electronics for drives and controls" are much like the very rapid changes in personal computer central processors and their speeds. Something better is always coming along. And soon.
Other upgrades are helpful too. Crane motors can be rewound. Old trolleys can be replaced. Drums, gearing, brakes, and other subcomponents can be rebuilt.
Remote control, instead of control by pendant or by having an operator aboard, is another option.
Increasingly, crane users "are gravitating toward radio control systems," says Mannesmann's Carlson. Newer units with greater reliability than those in the past is one reason. And spread spectrum radios using a 900 Mhz band can be installed "license free," he adds, which appeals to some users. Miniaturization of the radio's electronics means that units are smaller and more portable; they're also smarter and can control multiple cranes.
Handling the small loads
Smaller cranes for lighter loads have their place in this industry, of course. Many applications are suited to their capabilities. In fact, a widely cited study 10 years ago maintained that eight out of 10 loads handled in industries around the world were light loads of 300 lbs. or less.
That rule of thumb, suggests Columbus McKinnon marketing analyst Stuart Pattison, still prevails. (Companies under the CM umbrella make large cranes and the smaller units as well.)
If anything, it's likely the ratio is getting even closer to 9 out of 10 loads are 300 lb or less in today's U.S. industrial environment.
Installing a workstation crane, for instance, enables workers to perform tasks more easily and with a minimum of effort. Even a workstation crane designed for a 1,000 lb load, for example, requires the worker to only apply a 15 lb force to get the load moving horizontally, notes Pattison.
Rising costs of workmen's compensation, says Gorbel marketing manager Jeff McNeil, is another factor behind higher demand. OSHA's plans for ergonomic standards are being heeded by many who select workstation cranes, as is the general desire to keep workers productive and healthy at their jobs.
A strong economy with tight labor markets and skilled worker shortages in many geographic areas of the U.S. adds pressure to install cranes as well. "We sell more workstation crane systems in the Midwest," notes McNeil, "than we do in Florida."
Worker injuries can spur new system sales, he adds, as can changes to manufacturing processes and additions to product lines, especially in the bigger plants.
Standard Aero, an aircraft maintenance re-manufacturer in Winnipeg, Manitoba, Canada for example, had damaged parts and back injuries linked to employees trying to manually position 600-lb. loads with a motorized I-beam crane and electric hoist. By switching to free-standing workstation cranes with aluminum bridges, Standard Aero's employees need only apply a 5-lb. force to position the heavy load properly.
Modularity makes cranes a popular purchase as well, says Pattison. "They come to the customer much like an Erector set," he adds. Systems can be delivered in as little as 5 days, says Gorbel's McNeil. And both ceiling-mounted and free-standing enclosed track systems are available in kits, explains Spanco's Nolan.
Free-standing cranes give users features such as portability and resale capability. That's often important if a facility's lease ends in a few years or the nature of an end user's business shifts in the near future, notes Pattison.
No matter how small or large their capacity, cranes give your operations a big lift toward more bottom-line profitability.
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