Jaw crushers, despite their varying structural types, operate in essentially the same principle, differing only in the motion of the movable jaw. In short, the movable jaw plate periodically reciprocates around the suspension axis against the fixed jaw plate, sometimes approaching and sometimes moving away. When the movable jaw plate approaches the fixed jaw plate, the ore trapped between the two jaw plates is crushed by a combination of crushing, splitting, and bending and breaking. When the movable jaw plate moves away from the fixed jaw plate, the crushed ore is discharged through the crusher's discharge port under the influence of gravity.
Single-Oscillating Jaw Crusher Principle: The movable jaw is suspended on a central shaft and can swing left and right. As the eccentric shaft rotates, the connecting rod reciprocates up and down, driving the two thrust plates to also reciprocate, which in turn propels the movable jaw plate to reciprocate left and right, achieving crushing and discharge. This type of crusher utilizes a crank-connecting rod mechanism. While the movable jaw experiences significant crushing reaction forces, the eccentric shaft and connecting rod experience minimal forces. Consequently, large and medium-sized crushers are commonly manufactured industrially for crushing hard materials. Furthermore, when operating, the motion trajectory of each point on the movable jaw follows a circular arc centered on the axis. The arc radius is equal to the distance from the axis, with a smaller arc at the upper end and a larger arc at the lower end. This results in lower crushing efficiency, with a typical crushing ratio of 3-6. Due to its simple motion trajectory, it is called a simple swing jaw crusher.
Simple swing jaw crushers feature a compact and simple structure, with minimal forces on transmission components such as the eccentric shaft. Due to the small vertical displacement of the movable jaw, overcrushing of materials is minimized, and wear on the movable jaw plate is minimized.
Compound swing jaw principle: The upper end of the movable jaw is directly suspended on the eccentric shaft, serving as the connecting rod of the crank-connecting rod mechanism and driven directly by the eccentricity of the eccentric shaft. The lower end of the movable jaw is hinged to the thrust plate and supported on the rear wall of the frame. As the eccentric shaft rotates, the motion trajectory of each point on the movable jaw begins as a circular line at the suspension point (radius equal to the eccentricity) and gradually transforms downward into an ellipse. The ellipse becomes increasingly deflected as it moves downward, until the point of connection with the thrust plate forms a circular arc. Because the motion trajectory of each point on the movable jaw in this type of machine is relatively complex, it is called a complex swing jaw crusher.
Compared to simple swing jaw crushers, compound swing jaw crushers offer advantages such as lighter weight, fewer components, a more compact structure, better filling of the crushing chamber, uniform crushing of the material blocks, and forced ejection of the finished product by the lower end of the movable jaw. This results in higher productivity, 20-30% higher than that of a simple swing jaw crusher of the same specification. The material blocks experience a significant up-and-down tumbling motion at the lower end of the movable jaw, allowing them to be discharged in a cubic shape.
