Double Toggle Jaw Crusher
Double toggle jaw crushers have one fixed plate, while the other pivots about a top hinge. This moving jaw plate is shaped to move firmly and squarely against the material. There is no rubbing or grinding. Only compression, which produces a generally cubical product with minimum fines. The moving jaw is very well balanced, so 95% of the drive motor power is ued for crushing. While only 5% of the power is needed to move the jaw itself.
A double toggle jaw crusher is much larger, heavier, more moving parts and lower throughput than modern single toggle jaw crushers. The lower throughput statement is a bit misleading because it's partially attributed to the type of bearings they have versus modern crushers, so if one was to upgrade the bearings, throughput could be closer to that of a modern jaw.
Double toggle jaw crushes are really more about where the eccentric is located than anything. In a double toggle jaw crusher, the eccentric is located behind the swinging jaw. This has two main effects, – it keeps the eccentric out of harms way because there is no shock loading from the rock being crushed being transferred to the eccentric shaft and bearings. The other effect is a limited plane of motion for the swinging jaw which contributes to its lack of productivity. The jaw moves like a swinging door that is hinged at the top and is being pushed open and pulled closed at the bottom.