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Jaw crushers are amazingly powerful, able to reduce the hardest rock at very high reduction ratios.

Though their components are extremely rugged, this is not to say they’re invulnerable. However, if you listen, you can hear clear warning signs before they develop into serious problems. For example, the emergence of a knocking noise usually indicates that either the tension on the drive system is out of whack or that a jaw plate is starting to work loose. If no one notices, this can lead to an expensive fix with serious downtime.

Also take note of how often you replace the diaphragms of the oil sump and pump. If these are being replaced frequently, it can signify that the bushings on the swing jaw are excessively worn. When that occurs, it will result in an erratic jaw motion that may be difficult to observe directly, but that shows up as damage to the diaphragm.

Be careful to check for loss of oil in the sump. This can indicate a cracked diaphragm, and who wants that, especially at today’s oil prices?

The motion of the swing jaw derives from an eccentric shaft that drives its lower end, via the pitman and toggles. During the forward stroke, the rotating eccentric shaft puts considerable load on the pitman. The interface between these parts is a Babbitt bearing. This Babbitt is relatively trouble-free but if oil flow is interrupted, it can wear quickly. It’s therefore a good practice to periodically check the Babbitt for unusual wear. If badly worn, Pennsylvania Crusher can supply a replacement.

Jaw Crusher Examples

The Pennsylvania Jaw Crusher crushes by compression without rubbing. This view (above) exposes the operating elements which include the swing jaw, stationary jaw, Pitman and flywheel. Also visible is the oil bath which is the source of lubrication for the Pitman and the bearings. Most other Pennsylvania crusher models do not require an external flywheel.

This smaller version (above) of the powerful Pennsylvania Jaw Crusher is commonly used in glass plants to crush cullet. It also can crush minerals and recycle materials such as welding rods.

A down-the-throat view (left) of a small Pennsylvania Jaw Crusher, showing the ribbed jaw plates which are used when crushing glass (cullet).

Where to find help to keep your crushers crushing
This is the second of three articles on crusher maintenance. See my previous article for measures you can take to insure a longer life for ring hammers (granulators). For general questions, please comment here on this blog, and I’ll respond here. If you would like Pennsylvania Crusher to review your crusher maintenance procedures, or if you encounter service issues, please call me at 610-544-7200, or send your E-mail request to fschaffer@penncrusher.com. For more crusher information, visit Pennsylvania Crusher’s website at www.penncrusher.com. You can learn more about our crusher services, parts and remanufacturing.

Fred Schaffer
Service Advisor
Pennsylvania Crusher