Given their work mode, it’s a miracle hammers and breakers last at all. Proper maintenance can help them last longer.
Breakers can be taken for granted. They seem unstoppable as they bash their way through rock, concrete and asphalt. And while breakers aren’t inexpensive, their initial investment is far lower than that for the machines on which they’re mounted. It can be hard to remember that breakers are not indestructible, nor disposable, nor exempt from proper maintenance, and that downtime for a breaker, like downtime for any piece of equipment, leads to costly delays. (We will refer to this class of attachment as breakers for the sake of simplicity, although it also includes hammers.)
Proper Use of Hydraulic Hammers/Breakers
The first step in breaker preventative maintenance is to use the tool properly. “Operator skill remains the foremost determiner of breaker service life,” says Tom Munch, business development representative, Caterpillar. Here are seven things to keep in mind.
- Match the breaker to the carrier. The carrier (typically an excavator) must be of the right weight class and have the right hydraulic pressure and flow. Too small a carrier or too little hydraulic power will reduce breaker performance. Too much of either will create excessive heat and wear in the breaker. Also match the breaker to the application.
- Always have the tool tip perpendicular (90 degrees) to the material being broken.
- Avoid blank firing. Some breakers are designed to do this automatically; the operator will play a key role in any case. To prevent blank firing, the tool tip must be in contact with the surface and there must be downforce on the top of the breaker. With an excavator, the front of the tracks will be slightly elevated off the ground when there is sufficient downforce on the breaker.
- Stay in one spot no more than fifteen seconds. If the material has not begun to fracture after fifteen seconds, reposition the breaker on the surface. “A breaker is not a drill,” says Greg Henry, director of sales and marketing, Soosan Heavy Industries. “Keep it moving.”
- Don’t pry. A breaker is not a lever. Once the material is broken up, use another attachment (bucket with teeth, bucket with thumb, grapple) to remove it.
- Don’t lay the breaker down. “Keep it as upright as possible by resting it against a jersey barrier or similar support when not in use,” says Henry. “The limit is 45 degrees off upright.” This allows water to run off and keeps hot seals from being deformed by the weight of the breaker.
- Do a daily inspection. More on this in a moment.
Proper Hammer/Breaker Lubrication
Critical to the life of any breaker is proper lubrication. In a general sense this means grease, but the industry often uses the term “paste” to indicate that this is a special product. It has the consistency of an NLGI 2 or 3 grease but with a higher dropping point and additives to better manage heat.
And unlike most preventive maintenance procedures with intervals measured in hundreds of hours, lubing the breaker is done several times a day. The industry standard is to re-lube every two hours, but regular inspection may indicate a need for shorter intervals. Watch for seepage as grease runs down the tool tip; if the seepage stops, the tool must be regreased immediately. Another indicator is the presence of a ring of paste on the tool shaft three or four inches below the housing when the breaker is lifted. No ring means no grease.
Manual lubing is adequate as long as it’s done on a timely basis. Many times it is not. Autolube systems ensure grease is supplied as needed. An autolube system can be installed on the breaker. This is best when the breaker is moved from carrier to carrier and for rental breakers. A system can also be installed on the carrier and lines plumbed to the breaker. On-carrier systems work well when the breaker is always matched with the same carrier.
Regardless of the method, chisel paste consumption is typically two tubes per day in an autolube system or the equivalent when done by hand. Epiroc offers an environmentally-friendly chisel paste.
Hammer/Breaker Inspection Tips
A daily inspection of the breaker and its associated components is essential. “Inspect the bit, bushings and retainer pin for excessive wear,” says Robert Reister, product specialist, attachments, Bobcat. “Also inspect the bit and bushings for cracking or galling. Check the connection plate for any cracks or damage. Make sure there are no leaks in the hydraulic couplers and check for wear in any areas of hoses that may rub or cause friction.” Reister recommends checking the attachment connection and hose coupling systems every 8 to 10 hours.
Bushings should be inspected every 100 hours. Munch says that typical bushing service life is 200 to 500 hours for the lowers and 500 hours for the uppers. Wear is typically on the front and rear faces of the bushings. Cat lower bushings can be rotated 90 degrees to provide new wear faces and thereby extend service life. Some manufacturers provide a bushing wear inspection tool to make this process easier and more accurate.
Henry says it can take a year or more for problems to show up but once they do the breaker will likely need rebuilding or replacement. He cites pitting of the case-hardened surface of the piston is an example of such wear.
Some service can be done in the field. Lower bushings can often be replaced on site. But most service must be done in the shop. Munch suggests an annual internal reseal be done at the dealer.
Dan Vale from the service department at NPK says inspection of fasteners is essential and that all fasteners should be torqued to the specs provided by the manufacturer. He also emphasizes the need to clean and cap hoses when dismounting or storing the breaker in order to maintain a clean hydraulic system.
Reister says replacing damaged or missing signs and decals is an important maintenance step, especially for rental products.
Advanced Technology Comes to Hammers/Breakers
Advanced technology is appearing on breakers. All Cat breakers have auto shutoff to prevent blank firing. Their Next Generation excavators will reduce power to breakers after 15 seconds of no movement and will shut down the breaker after 30 seconds without progress.
Rich Elliott, product and application specialist, Epiroc, says all their mid-size breakers include auto control. This feature senses piston stroke travel and when resistance drops, auto control runs the breaker at twice the frequency but half the power. On their large breakers Epiroc provides an Intelligent Protection System. The IPS has the functionality of auto control plus an auto shutoff feature to prevent blank firing.
What does this technology mean for preventative maintenance? “These systems have no significant preventive maintenance needs of their own,” says Elliott, “yet they substantially reduce the preventative maintenance needs for the breaker.”
PRODUCTS FEATURED IN THIS ARTICLE:
- Cat® hydraulic hammers
- Soosan hydraulic breakers/hammers
- Epiroc hydraulic breaker
- Bobcat hydraulic breaker
- NPK hydraulic hammers/breakers
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