Break on through: manufacturers offer tips on maintaining hydraulic breakers and hammers.
Hydraulic breakers and hammers tackle some of the toughest tasks the construction and demolition industry has to offer. Everyday wear-and-tear that comes with the job can't be avoided entirely, but a good operator can extend the life of wear parts with attention to regular maintenance.
"A good breaker is designed to protect its major components from any damage," says Rich Eliott, hydraulic applications manager for Atlas Copco Construction Tools LLC, Westfield, Mass. "Wear items like bushings, seals and the working tool should ideally absorb most of the abuse."
Wear items will all eventually need to be replaced, but operators can extend the life of certain wear parts with careful attention to maintenance, according to Tom Pinchuk, attachments marketing manager for Ingersoll Rand, Davidson, N.C., which produces the Tramac line of hydraulic breakers. The tool itself is the first part that's going to wear, he says. However, "the better the operator, the lesser the wear," Pinchuk adds.
Retaining pins, which hold the tool in the breaker, are also among the first parts that need to be replaced, even under the best use and conditions, Pinchuk says. When they wear out, they can cause the tool to seize within the breaker. He says using non-OEM specification tools can reduce the life of the pins, and once worn, they can cause excessive movement of the tool, leading to damage of the bushing and the front end.
The bushings are another key wear part. With the tool going up and down some 300 to 350 times per minute in most breakers, the bushing is bound to wear down eventually. However, too much wear will damage the front end and the tool, Pinchuk says.
Replacement schedule for wear parts on breakers varies widely, according to Donald Dennis, product support manager for the Caterpillar (Peoria, Ill.) line of impact products. "Parts most prone to damage are wear items, such as tools and tool bushings on any hydraulic hammer. These service items need inspection, and replacement varies widely based on maintenance schedule and a good operator, a key person who can extend wear life of components," he says.
OUNCE OF PREVENTION
Greasing is the No. 1 maintenance priority, according to many manufacturers. "Unless you have an automatic lubrication systems, grease, grease, grease and grease some more. You have steel against steel, which generates a great deal of heat. So you need a good lubricant and a lot of it to prevent wear of the demolition tool and tool bushings," says Greg Smith, marketing communications manager for Allied Construction Products LLC, Cleveland.
"The rule of thumb is to grease every two hours, or when the operator notices the shaft of the tool starting to dry up," adds Pinchuk.
That's assuming the contractor is using chisel paste and not standard grease, according to Elliott. "In that case, the breaker should be lubricated about once every hour or more, depending on the application. You should always see a film of chisel paste running down the working tool. If you don't see any or see a shiny spot on the tool, it's time to apply more lubrication." High dust environments require more frequent greasing to keep the tool bushing area clear of dust and debris, Dennis adds.
Greasing is the key element in a daily maintenance routine, which provides a strong foundation in keeping a hydraulic breaker performing at optimum levels, according to Tom Witt of Breaker Technology Inc., Solon, Ohio. "A simple but important practice, such as using the correct grease can save 50 percent of your potential maintenance expense," Witt says.
Operators would also be wise to conduct a visual daily inspection of the breaker and its components, Witt advises. "A good visual daily inspection of bolts, tie rods, hardware, retainer pins, tools, etc., will also prevent costs by catching problem areas early," he says.
Wear on the tool bushing should also be checked, says Elliott. "Every breaker has a recommended wear spec for the maximum clearance allowed between the tool and bushing," he says. "Contractors can do a basic visual check on this using something with a defined width, like a drill bit. If you can slide a l/4-inch drill bit between the tool and bushing on a breaker with a recommended clearance of 5/16 inches, then it's time to remove the tool to get a precise measurement to see if the bushing and/or the tool has worn beyond its specification."
Pinchuk advises operators to make sure checking the connection point between the breaker and carrier is on the daily checklist.
Dennis says the operator should also inspect the tool retainer slot area for burrs once every 50 hours as part of a daily maintenance routine.
In addition to daily regular maintenance, many manufacturers recommend a yearly rebuild. "Annually, depending on utilization, you should rebuild your breaker," Pinchuk advises. "Most manufacturers offer complete seal kits to make this task easy."
The entire breaker gets inspected, and all wear parts are replaced during a typical rebuild, says Elliott. While once a year is pretty standard, "larger breakers used over time in heavy duty applications will naturally need more frequent rebuilds than small breakers in light duty applications," he says.
In addition to adhering to preventive maintenance schedules, manufacturers have a number of tips to help operators keep their breakers running at their best.
Manufacturers see operators repeating some of the same common mistakes when using breakers. Avoiding some of these pitfalls can go a long way to saving on wear and tear and preventing more serious damage.
"First of all, the carrier and the breaker have to be a match," says Elliott. "Once you get the right carrier, hydraulic oil flow and pressure needs to be set within the breaker's operating specifications, or you could have some serious problems, not just with the breaker, but with the carrier as well."
Mismatching the breaker to the application is another common error, says Elliott. "You shouldn't use a small breaker mounted on a skid steer to reduce oversize boulders in a quarry, and you shouldn't use a l0,000-pound breaker to break up a small driveway. In either case, you're putting a breaker in an application for which it wasn't intended and increasing the risk of damage," he says.
Improper use also causes a host of problems. Pinchuk advises users to make sure they are putting enough downward pressure on their breakers, otherwise they run the risk of blank firing--where the piston fires but does not come in contact with the tool, which can damage the piston. "The firing energy has nowhere to go, and therefore you get metal to metal contact within the breaker," he says.
Operating with the work tool at an angle to material is another common mistake and causes higher wear on the tool and bushing, says Dennis. He also cautions operators against prying with the hammer, which causes bending forces on the tool.
Having an experienced operator goes along way in preventing the damage caused by misuse, such as running the breaker too long in one spot, according to Smith. "If the operator continues to run the breaker/ hammer in one spot without breaking anything, then the operator is only creating unnecessary heat in the breaker and the carrier," he says.
Elliot agrees, "A breaker should be repositioned every 15 to 30 seconds if it is not penetrating the material to avoid heat buildup, which can actually damage the internal components of the breaker."
Correct operation is only half of the equation, however. "Preventative maintenance is the key to keeping a breaker productive and minimizing unscheduled and costly downtime," Elliott adds.
Since preventive maintenance is so integral to the optimum performance of hydraulic breakers, a variety of automated features are available to make maintenance easier.
"Manual lubrication can be time-consuming, and obviously downtime is not a good thing," says Rich Elliott, hydraulic applications manager for Atlas Copco Construction Tools LLC, Westfield, Mass. "So several manufacturers offer some type of automatic lubrication system for their breakers."
Automatic greasers are available in two configurations--breaker mounted or carder mounted. Each brings its own set of benefits and limitations. Packages mounted on the carrier tend to have larger reservoirs, so an operator doesn't have to refill as often, says Tom Witt of Breaker Technology Inc., Solon, Ohio. However, "if you're moving the breaker from machine to machine, you'd have to have one on each. If you have a rental fleet, it might be more advantages to have it on the breaker itself," he adds.
Some breakers feature an automatic shutoff to eliminate blank firing when the tool is not in contact with material, says Donald Dennis of Caterpillar Inc., Peoria, III. This reduces stress on the hammer components.
Other automated options include flow controls that divert excessive flow; energy recovery systems that recoil energy into the next blow; and automatic variable speed breakers, which constantly adjust the frequency and impact energy of the breaker so that it always hits with an optimal combination of both, according to Tom Pinchuk of Ingersoll Rand, the manufacturer of the Tramec line of hydraulic breakers.
The author is associate editor of C&DR and can be contacted at firstname.lastname@example.org.
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|Title Annotation:||EQUIPMENT FOCUS|
|Publication:||Construction & Demolition Recycling|
|Date:||Nov 1, 2007|
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