Jaw crusher maintenance

A lot can be saved or achieved by giving your machine the attention it needs, including costs and time your crews could be spending elsewhere.

With proper planning and preparation, maintenance programs can be made easier – and more effective. Importantly, operations can meet time management, cost savings and safety goals by employing good maintenance strategies.

Check jaw dies daily, making sure bolts are kept tight.

“Successful jaw crusher maintenance requires the right resources, the right tools and the right approach,” says Bill Macini, a Telsmith service technician.

Certainly when an operation is down, whether for preventive maintenance or component failure, there is always the pressure to get the plant up and running as soon as possible.

“So workers may take shortcuts that ultimately cost the operation more in the long run,” Macini says. “Crews need to be trained in the proper methods, and management needs to provide the support and resources to do the job correctly.

Macini offered several tips to enhance your own maintenance.

Cleanliness is key: Keep oil systems free of contamination. With a “production, production, production mentality” comes the attitude of, “let’s hurry up and change the oil.” But crews don’t bother to clean out any sludge buildup in tanks; and the new oil becomes contaminated.

A periodic oil analysis offers a heads-up about the condition of the machine. Also, changing the oil requires clean buckets, clean rags and storage in a clean environment.

Keep the breathers clean as well, and keep the right gaskets and oil filters on hand. Don’t run oil filters into the “red.” Always have the right replacement parts and cleaning components set aside and ready to go. Be proactive, and remain prepared as oil-change intervals come up.

Keep the toggle area clean, particularly before any crusher adjustments. It’s best to wash out the toggle seats and plates daily, as wet material buildup results in a gritty compound that grinds down components, causing premature wear.

Also, remove dirt and debris from crusher frame surfaces and from areas around the machine. Monitor discharge chutes for any obstructions and check for any material buildup under the jaw to avoid excessive wear on the pitman.

Conduct regular inspections: As specified by owner’s manuals, crews should follow the discipline of daily, weekly and monthly recommended inspections. While there are many inspection items listed on a manufacturer’s maintenance schedule, several are worth highlighting.

Check jaw dies daily, making sure bolts are kept tight. Check cheek plates for any excessive wear that may affect the mainframe of the jaw. Monitor flywheels for cleanliness, tightened bolts and potential cracks; and make sure drive belts aren’t worn or cracked.

Monitor operations and log data: Log your amperage draw to see if it changes from day to day. If amperage is exceeding normal levels, it could be a signal of bearing problems or loose belts.

Additionally, log your coast-down time daily. How long does it take the machine to come to a dead stop? If the time starts to shorten, this could indicate a bearing problem. Check all indicators and switches daily for proper operation – as they are integral to proper shutdown in the event of issues such as high temperatures or low hydraulic pressures.

Telsmith jaw crusher

Don’t over-extend wear parts: Avoid running jaw dies so long that they become too thin. You may find that you can no longer flip them over – and now, you’ve lost half the wear. To get the full life of the manganese, change them out sooner than later.

Know the right fit for you: Consider that if you’re an operation resigned to a less-than-the-best maintenance regime, you’ll be better off with a greased-versus-oil bearing machine. Requiring less-intensive maintenance than that of oil-lubricated systems, grease machines need a proper cleaning of the fittings and the application of the right grease. Applying the wrong grease (because that’s what’s on the shelf) is not an option, as this shortcut can ultimately cause equipment failure.

Update your equipment: As an example, Macini points to modern crusher designs that incorporate hydraulic tensioning cylinders that replace conventional toggle tension rods and springs. As a result, the tension cylinders automatically maintain the proper tension on the toggle, eliminating the need for spring adjustment. With proper tensioning being automatic, producers save time as well as reduce wear and tear on parts.

Furthermore, two oversized hydraulic cylinders behind a moving toggle beam enable all closed side setting (CSS) adjustments. A flip of a switch extends or retracts the cylinders and the adjustment is complete – and made safely without shims being needed at any time. For safe toggle maintenance, the hydraulic adjustment cylinders push the pitman forward where it is locked into position with lockout pins, which insert from the side.

Then hydraulic tension cylinders, mounted on the side of the toggle, pull the toggle beam back, allowing it to be safely lowered away. “Operations stress that this safety aspect is very important to them as they no longer need to have workers with wrenches climbing in, around or under this equipment,” he says.

To prevent crusher damage, downtime and difficult maintenance procedures, the hydraulic overload relief system opens the crusher when internal forces become too high, protecting the unit against costly component failure. After relief, the system automatically returns the crusher to the previous setting for continued crushing.

“Producers say that hydraulic relief is a huge advantage for them,” Macini says.

On modern crusher designs, hydraulic tensioning cylinders automatically maintain the proper tension on the toggle, eliminating the need for spring adjustment.

He goes on to explain that typical older-style crushers may make use of a shear toggle that acts somewhat like a fuse. In other words, the toggle is a weak link that bends or breaks away when pressure becomes too great, and prevents further damage. But once the toggle is sheared or broken, the maintenance crew may have to spend up to four hours to remove and replace it, and that assumes the part is available.

“With toggle shear occurring more than five times per year, high maintenance costs can adversely affect profitability,” he says. “So, hydraulic relief is a big advantage in modern crusher design.”

Develop a maintenance discipline: So ditch the shortcuts. As with anything, you get out of it what you put into it. Learn to do maintenance jobs right the first time, and continue the discipline throughout the life of the equipment. The payoff is measurable in time and cost savings, and a far safer working environment.

Take note
Once a toggle is sheared or broken, maintenance crews may have to spend up to four hours to remove and replace it.

Carol Wasson is a veteran freelance writer for the aggregates and construction equipment industries.

Photos: Telsmith