What is a Jaw Crusher?

Jaw Crusher, also known as stone jaw crusher, is popular equipment for coarse or medium crushing of stone or ores whose compressive strength is under 320 Mpa. Crushing chamber of jaw crusher is composed of movable jaw and fixed jaw. These two jaws move in a way which is the similar as the jaws of the animal, in this way, the stone or ore will be crushed. The following figures are for your reference:

Based on the width of the feeding opening size, jaw crusher can be divided into big, medium and small types. Feeding opening size of big jaw crusher is bigger than 600mm; width of the medium type jaw crusher is between 300 and 600mm; width of the small jaw crusher is less than 300mm.

Working part of the jaw crusher contains two jaw plates. One is fixed jaw plate which is fixed on the front wall of the stone jaw crusher vertically; the other is a movable jaw which is inclined and forms a crushing chamber with the upper part is larger than the lower part. The movable jaw does reciprocating motion against the fixed jaw, getting close to the fixed jaw and get away from it again and again.  When it gets away, the materials can feeding into the crushing chamber, the final crushed stone or ore will be discharged from the lower part; when it gets close, materials between the two jaw plates will be squeezed and crushed.

Based on the different swing methods, it can be divided into three types: single toggle jaw crusher, double toggle jaw crusher and comprehensive swing jaw crusher.

Working principle of single toggle and double toggle is similar with each other. But the moving track of their movable jaw is different. The movable jaw of single toggle jaw crusher suspends on the support shaft. Hence, when the movable jaw moves to and fro, the moving track of every point on the movable jaw is a circular arc, and the horizontal stroke is small in the upper part and large in the lower part. When the stone or ore falls into the crushing chamber, the bigger stone is on the upper part where the compression amount is not enough. Hence, big stones or ores in the upper part shall be squeezed for many times. However, the majority of the crushing load centralized in the lower part. In this way, the jaw plat works unevenly and greatly declined the output capacity of the jaw crusher. Furthermore, single toggle jaw crusher has the disadvantages of small vertical stroke, small abrasive action and low discharge speed. It also has the advantages of light abrasion and less over-crushed products.

The movable jaw of double toggle jaw crusher also works as the connecting rod of its crank-link mechanism. Driven by the eccentric shaft, the moving track of upper point of the move jaw is just like an ellipse. The ellipse is small in the upper part and big in the lower part. Its horizontal stroke is bigger in the upper part and smaller in the lower part which is also opposite to the single toggle type. In this way, the big stones or ores in the upper part can have enough compression amounts. Furthermore, the vertical stroke of double toggle jaw crusher is 3 times larger than the horizontal strokes especially at the discharge opening. That is greatly improving the output capacity. 

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