The special design of jaw crusher
A Jaw Crusher is one of the main types of primary crushers in a mine or ore processing plant. The size of a jaw crusher is designated by the rectangular or square opening at the top of the jaws (feed opening). For instance, a 24 x 36 jaw crusher has a opening of 24′ by 36′, a 56 x 56 jaw crusher has a opening of 56′ square. Primary jaw crushers are typically of the square opening design, and secondary jaw crushers are of the rectangular opening design. However, there are many exceptions to this general rule.
A Jaw Crusher reduces large size rocks or ore by placing the rock into compression. A fixed jaw, mounted in a ‘V’ alignment is the stationary breaking surface, while the movable jaw exerts force on the rock by forcing it against the stationary plate. The space at the bottom of the ‘V’ aligned jaw plates is the crusher product size gap, or the size of the crushed product from the jaw crusher. The rock remains in the jaws until it is small enough to pass through the gap at the bottom of the jaws.
Jaw Crushers are designed to impact on a rock particle placed between a fixed and a moving plate (jaw). The faces of the plates are made of hardened steel. Both plates could be flat or the fixed plate flat and the moving plate convex. The surfaces of both plates could be plain or corrugated. The moving plate applies the force of impact on the particles held against the stationary plate. Both plates are bolted on to a heavy block. The moving plate is pivoted at the top end (Blate crusher) or at the bottom end (Dodge-type crusher) and connected to an eccentric shaft. In universal crushers the plates are pivoted in the middle so that both the top and the bottom ends can move. Jaw crusher:http://www.crusher-machine.com/1.html
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The Blake crushers are single or double toggle drives. The of the toggle(s) is to move the pivoted jaw. The retrieving action of the jaw from its furthest end of travel is by springs for small crushers or by a pitman for larger crushers. As the reciprocating action removes the moving jaw away from the fixed jaw the broken rock particles slip down, but are again caught at the next movement of the swinging jaw and crushed. This process is repeated until the particles sizes are smaller than the smallest opening between the crusher plates at the bottom of the crusher(the closed set). For a smooth reciprocating action of the moving jaws, heavy flywheels are used in both types of crushers.