Service crane purchasing tips: select the correct size and features for your application
Published in: Equipment Today Magazine
Date: 2/1/2005
By: Bennick, Curt
Cranes on mechanic trucks can either boost productivity or become a constant source of irritation for your field service techs, depending on how they are spec’d. Choosing the correct crane boils down to working with the service technicians to understand your particular application.
“You probably need to survey your service technicians to see what exactly they need to do their job, and get back to the shop safely and in the most expeditious manner,” advises Gary Hanson, Western U.S. regional sales manager, Stellar Industries.
Size it correctly
The most common mistake customers make is selecting a crane that is too small. “It doesn’t lift what they thought it would,” notes Tim Worman, product manager for commercial vehicles, Iowa Mold Tooling (IMT). They may misunderstand how the maximum rated capacity relates to their application.
There are a couple of components critical to selecting the correct size crane: the weight of the objects to be lifted, and the distance of the object from the centerline of the crane. “An individual should not always look at the maximum that the crane can lift, because the rated maximum is typically measured 3 to 5 ft. from the centerline of the crane’s rotation point,” says Worman. “Not many people do actual lifts at that radius.
“You really want to look at what your realistic lift conditions are,” he continues. “If you want to lift 2,000 lbs. at 10 ft., you would need a 20,000 ft.-lb, crane.” Too often customers get caught looking at the maximum capacity of the crane instead of the load chart to determine the size of the crane needed at their typical reach.
Estimating the weight of the objects to be lifted also presents challenges. “When you look at what you want to lift weight-wise, factor in 5% to 10%,” advises Worman. “You are going to find an instance where you think you know what something weighs, but you really don’t. You never want to order a crane right on what you think you are going to lift every time. You always want to be a little bit bigger.”
The cost does increase with the larger cranes, so you need to evaluate your needs carefully. Buying the biggest crane that is compatible with the GVW rating of your truck is not always the best practice. “If you buy the maximum crane to fit your GVW and you only need a crane that has half of that, you are spending a lot more money than you are going to recoup,” says Worman.
Jerry Nichols, Feterl Mfg. Corp., offers guidelines to help contractors choose the correct size crane. “You should buy a crane that will take care of 80% of your needs minimally,” he recommends. After that, it just goes with your budget. If you can’t get a crane that is going to take care of 80% of your lifting, you need to hire somebody out to do the work from a safety standpoint. You are not going to be a very happy customer if you settle for less.”
“We have never had anybody upsize their crane and be unhappy with it,” says Jason Ollerich at Feterl Mfg. Corp. “We have had guys who wanted to save that couple thousand dollars and go with the next size down crane and they were unhappy with it.”
Isolate stress
A problem with some mechanic trucks equipped with a crane is that you can’t open or close the side pack doors while there is a load on the crane. “If you get your crane out there at maximum reach and maximum load, there is a very good chance that the body is going to rack enough that you cannot open your doors or you cannot close them,” says Hanson. “That places additional stress on the body and shortens its life.”
Isolated crane mounts offer a solution to this problem. “The crane tower does move while you are using it,” notes Hanson. Isolated crane towers allow for this movement without transmitting it into the side packs. “That is going to give longer life to those side packs.”
Nichols agrees, noting, “On service bodies without an isolated crane tower and outrigger structure, stress cracking may occur, compromising the service body structure. Make sure the crane tower is strong enough to accommodate the crane you are contemplating.”
Ease of use
If something is hard to use, your service technicians will probably avoid it. That includes outriggers on the technician’s truck. These stabilizers come in three different types: manual out/manual down; manual out/ hydraulic down; and hydraulic out/hydraulic down.
“We don’t see many of the manual out/manual down outriggers anymore,” says Worman. “The market has kind of walked away from that.”
Instead, hydraulic-powered units are gaining in popularity. “I see a trend to hydraulic for the simple reason that if they do not get used regularly, the manual outriggers have a tendency to get frozen in one spot,” says Hanson. “At that point, the guy doesn’t use them, risking the possibility of a rollover. Those stabilizers are on there for a reason–to make that footprint as wide as you can to keep it stable.”
The industry is currently seeing a transition from manual out/power down to fully hydraulic operation. “If you have power outriggers, the operator is more likely to set the outrigger appropriately vs. getting tired of pulling out the outrigger every time,” says Worman. “If you do not deploy your outriggers, you have a stability issue.”
The same theory applies to hydraulic crane extensions vs. manual extensions. “We have found that after a period of time manual extension becomes harder and harder to pull out,” says Nichols. “So eventually they quit pulling it out. From a safety standpoint, you want to use hydraulic because they will always use that when they really should be using it.”
Manual pullouts are usually only popular on lower-end units. “The customer who is looking for manual pullouts is the one buying purely on cost,” says Worman.
Hydraulic extensions are definitely more popular. “Anyone using cranes on a repetitive basis, and concerned with productivity, will definitely want hydraulic extend.” says Worman.
Features add productivity
Depending upon how much you use your crane, several features justify the added purchase price through increased productivity. A few of these, such as proportional controls. may also increase the safety factor.
“If you do not have proportional controls, you either have a slow crane or a fast crane all of the time,” says Ollerich. “A slow crane is really a pain when you are running the crane empty, but the fast crane is half dangerous when you have a load on it. All of ours have proportional control standard.”
Proportional controls allow the operator to work at the correct speed for the task. “With the proportional controls, you can feather those controls and you can really slow the use of the crane down ” says Hanson. “If you are setting a critical piece of equipment, you have very tight control over what you are doing. That’s a safety issue.”
Hanson adds that multifunction control–where you can boom tip or down and rotate at the same time–also aids productivity. “You can rotate and boom tip. That allows you to go diagonally out of a tight spot,” he explains.
Line speed is another feature that can increase productivity when the crane is moved and used several times a day. “If you are going to six different jobsites, that line speed is going to be more important because you are going to be storing all of the cable and running it out a lot,” says Ollerich.
This has led to a growth in popularity of high-speed winches. “The market has really pushed to have 60-fpm winch capability,” says Worman.
Radio remote controls are also becoming popular features. “It allows you to operate the crane while you are outside the are where the crane could be swinging the load,” says Hanson. “That is a huge safety factor as far as we are concerned.” Acceptance of radio technology has increased along with reliability and durability. “The radios become better and better every day.”
Improvements in technology have addressed many prior concerns. “Market-wide, reliability has been a long-standing issue,” says Worman. “Radio remote is much more reliable then it ever has been.”
But Nichols advises using a tethered backup. “You should have both wireless and umbilical cord so if something happens to the wireless, you can still work,” he emphasizes.
Other features you might want to consider when looking at a crane include the actual weight of the crane, and onboard diagnostics. Some of the newer cranes weigh less, which means you can carry more payload. In addition, the advent of Controller Area Network (CAN) technology on some models has led to onboard diagnostics to troubleshoot problems.
It all boils down to how much you use your crane as to which technologies make sense. But every crane must be properly sized for your particular application.
COPYRIGHT 2005 Cygnus Business Media