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Articles from CONSTRUCTION PLANT & EQUIPMENT (459 Articles), CONCRETE PLANT & EQUIPMENT (166 Articles), BREAKERS - CONCRETE (89 Articles)











Breaking without busting

Automatic maintenance and routine overhauls can pack more power into your breaker.
All hydraulic breakers, regardless of design or manufacturer, have the task of shattering, cracking or splitting material. The assignment is not exactly gentle on the equipment.

Wear and tear is an outright certainty, so maintaining the breaker is vital to keep it running at peak efficiency.

Little can be done to prevent a breaker from eventually meeting its demise, years later. But the life cycle and performance of a given unit can be greatly enhanced with proper maintenance, which can be viewed from three separate perspectives: routine maintenance by the producer, periodic rebuilds by the manufacturer, and preventive maintenance features in the breaker itself.

The routine stuff
When talking about routine breaker maintenance, it would be irresponsible to do so without mentioning lubrication. Without lubrication, metal-to-metal contact between the breaker's tool and bushing would cause the bushing to wear out quickly, subsequently exposing the breaker's major components to serious damage. Although it is highly unlikely that an operator would ever completely forget about lubrication, a few key points on proper greasing are worth discussion.

The lubrication process begins by applying downward pressure on the tool to ensure that it is pushed all the way into the breaker; this eliminates the possibility of grease filling into a chamber between the piston and the top of the tool. Lubricant should be applied until it comes out of the lower bushing area, which indicates that the breaker cavity is full and ready to go to work. A paste or grease film should always appear on the tool at the lower bushing, while the breaker is operational. The absence of grease is a good visual indication that it is time to apply more lubricant.

Several breaker manufacturers offer their own chisel paste or other lubricant designed specifically for breakers. Standard grease is inferior to specially designed chisel pastes because the heat and pressure from the working tool will cause the grease to melt and run. In turn, this increases the frequency of lubrication applications. Although the cost for a tube of chisel paste or special shank grease is higher than the price of regular grease, manual lubrication with paste is required, on average, once every two hours, compared with intervals of one hour or less using standard grease.

If the operator has to stop work to apply grease twice as often, this can cost a producer far more in downtime than can be saved using the cheaper lubricant. Additionally, using cheap grease may save money in the short term, but could eventually add up to thousands of dollars in tool steel replacement costs.

Even with the very best lubrication techniques, the bushing will wear out and need to be replaced at some point. Measuring the bushing diameter to see how much it has worn often requires that the tool be removed. A simple measurement trick that can be performed, without disassembly, is to try to slide a 5mm drill bit between the tool and bushing. Typically, a maximum of about 6mm of space is the allowed wear limit. If the drill bit fits between the tool and the bushing, the tool should be taken out so the bushing can be properly measured to see if it has reached the designated wear specification.

While the importance of lubrication and wear items is quite well understood, not all producers may be aware that many hydraulic breakers feature a nitrogen gas assist that should also be maintained when required. Expansion and contraction due to heating and cooling will lower the gas pressure in the breaker's piston accumulator, similar to the way that car tyres will gradually lose air.

Unlike frequent greasing, gas pressure checks do not need to be done daily. And unlike car tyres, there is nothing visual to suggest when the pressure should be checked. Instead, simply monitor the breaker's performance. If there is a noticeable drop in the breaker's power output, it could be an indication of low gas pressure. Manufacturers recommend using a special kit and following the operator's manual while performing this check.

Guidelines about operation may not immediately be thought of as maintenance-related, but they are just as critical as lubrication to the physical condition of the breaker. A breaker that is lubricated properly but operated incorrectly could suffer the exact same wear and tear on the bushings and tool, as if there had been no lubrication at all.

One specific aspect of proper operation involves the hydraulic flow going from a carrier to the breaker. Although machine specifications may indicate a good match, a carrier should be tested at least once a year - more often in heavy-duty applications - to ensure that it is delivering the correct fluid levels to the breaker. Unfortunately, many producers fail to have their carriers tested, either due to a lack of awareness or to avoid the expense.

It is important to realise that flow problems can pose just as much risk of damage to an excavator or other carrier as they would to the breaker. Improper machine set up is a problem from which no breaker can hide.

Just like new
Although often classified as an attachment, a hydraulic breaker is a specialised piece of machinery. Like most products, many maintenance and operation issues can be handled correctly in the field. But even with proper care, a hydraulic breaker will require a periodic overhaul to replace all of its wear components.

The terminology for such a job varies. Rebuild, refurbishment and recondition are a few of the phrases out there. There is no set timetable for a breaker rebuild, as it largely depends on the application and size of the breaker. The type of repair that is actually done will differ as well, depending on who is doing the repair and on customer preferences.

Common practice with a recondition is to replace every single wear item on a breaker, as well as performing a complete and thorough inspection of the unit. Bushings, tools and retainer bars are replaced, while the piston, cylinder and pressure accumulator are inspected. The repair work is usually topped off with a paint job.

Occasionally, a breaker that has not been heavily used will be brought in for a recondition. Such a machine may not have experienced much wear and tear, so the customer may be given the option of replacing some parts while trying to get more life out of others.

A more frequent occurrence is for a breaker to have certain wear items that only have a few months of use left. The customer still has the option of leaving these parts in.

However, doing this would mean a return trip to replace the parts just weeks or months later, once they have run their course. In addition to being more convenient, another upside of immediately replacing all the items is that the manufacturer may offer a renewed warranty, since the breaker has essentially been refurbished up to near-new condition. The same guarantees may not apply if some parts are not replaced and something goes wrong before the next repair.

It is generally recommended to take a breaker to the manufacturer, distributor or another qualified professional for a rebuild or recondition. However, many hydraulic breakers, especially the smaller varieties, are designed so that they can be more easily maintained. Therefore, end users with the appropriate training or experience can certainly take on the task of refurbishing their own breaker.

Automatic maintenance
For the most part, producers are not going to rebuild a breaker on their own because of the enjoyment they get from it. It is usually done as a cost-cutting measure. By the same token, having a breaker than can handle some aspects of maintenance on its own can create a more profitable situation.

'Automatic' is a big-time buzzword for today's equipment. Anything the equipment can do by itself, to take another task out of the operator's hands, should minimise downtime and increase overall productivity. Incorporating a number of automatic technological features also applies to hydraulic breakers.

Not surprisingly, nearly every breaker manufacturer has some technique for automatic lubrication. Different methods are employed on various breaker sizes and brands. A number of systems use a hose that runs from the carrier to apply consistent lubrication to the breaker. Some manufacturers produce breakers that come standard, with a lubrication cartridge mounted directly onto the breaker. With this system, literally all that is required of the operator is to change the tube when it is empty. Even with the 'automatic' lubrication system, the operator still needs to periodically check for grease film on the tool to ensure the system is operational and properly adjusted.

More lubrication than normal is needed for particularly dusty applications. Some breakers feature an optional system to protect the breaker from dust penetration, by providing an additional seal that prevents debris from entering the unit. This system also keeps chisel paste where it belongs, to allow the breaker to run longer without risking wear and tear from a lack of chisel paste.

Another feature that assists in preventing potentially serious harm to a breaker is a power management system. Found on some larger breakers, this system is a tremendous preventive maintenance asset in jobs, where lighter material is being broken. Rather than unleashing a full-power blow, a breaker equipped with power management can limit itself to 50 per cent power until it hits against hard material that dictates a need for full impact energy. If full power is used in light material, the breaker's working tool will literally fire out through the material, and only a metal-to-metal stop against the breaker's retainer bars will keep the breaker intact. Obviously, such a situation would cause unnecessary strain on the machine without power management in place to intervene.

Conversely, in applications where extremely hard material must be broken, damaging shock waves can be reflected from the material into the breaker's tool and piston. One unique system allows this rebounded energy to be collected in a high-pressure accumulator, which effectively protects the internal components from the shock waves.

As an added bonus, the breaker can then deliver the accumulated energy in the next blow.

Treat it right
Breakers are charged with the unforgiving task of pounding apart hard material without falling apart themselves. Some producers take the approach of using a breaker when they need it and throwing it to the side when they don't because 'it's just a hammer.' In reality, hydraulic breakers are specialised machines that require maintenance, just like any other piece of machinery on the job site. Through new design and technology, manufacturers have simplified breaker maintenance to make it a user-friendly task. Give a breaker the time and attention it deserves, and it will return the favour with productive and impressive results.

Keith Becker and Matt Cadnum are service managers for Atlas Copco Construction Tools.

















Tuesday, 23 April, 2019 4:38pm
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