How to Adjust the Discharge Opening of a Jaw Crusher

The thrust plate (also known as the elbow plate) of a jaw crusher not only transmits power to drive the movable jaw plate in a back-and-forth motion but also serves as a safety device. Adjusting its length can also be used to regulate the discharge opening.

When non-crushable objects (such as steel balls or metal chunks) enter the crushing chamber of a jaw crusher, the rear thrust plate serves as a safety component to protect the machine’s main parts from damage. The rear thrust plate is typically cast as a single piece of cast iron, with a slot or several small holes cut into its center to reduce its cross-sectional strength; alternatively, it can be cast as two separate pieces connected by screws (or rivets) to form a composite thrust plate. When non-crushable objects enter the crushing chamber, the equipment is subjected to a load, and the immense crushing force is transmitted to the thrust plate, causing it to fracture or the screws of the composite thrust plate to shear. The machine then stops operating, thereby serving as a safety mechanism.

As the tooth plates wear down, the discharge opening gradually increases, and the product size becomes coarser. To obtain a qualified product particle size, the discharge opening size must be adjusted periodically. There are primarily two methods for adjusting the discharge opening:

(1) Shim adjustment: This involves placing a set of shims between the support seat of the rear thrust plate and the rear wall of the frame. By adding or removing shims, or by changing their thickness, the discharge opening can be adjusted. This method features a compact structure and reliable adjustment, and is commonly used in large and medium-sized jaw crushers.

(2) Wedge adjustment: This method uses two wedges placed between the rear support of the thrust plate and the frame, and is suitable for small-scale crushers.

We welcome you to visit OCP Heavy Industry to tour our facilities and inspect our crushers. For inquiries regarding crusher selection and production line design, our experts will recommend the most suitable crusher and design an optimal production line based on the properties of your material and the characteristics of your production location! Click the website chat to consult with us for free immediately.