Double toggle jaw crushers are usually used for crushing hard, abrasive rocks, glass and ferrous metals. Unlike single ones, double toggle jaw crushers are much heavier and have a lot of moving parts. Plus they don’t include rotary motion. Instead they crush materials between two massive jaw plates. The crushing process happens, when the feed material between the two jaws is compressed. Another difference between the double toggle jaw crushers and the single ones, is the position of the eccentric. In a double jaw crusher, the eccentric is found behind the swinging jaw. That helps protect the eccentric from any further damages.