How to ensure smooth contact between the new jaw plate and the machine surface during installation?

The installation quality of the jaw plate of the jaw crusher is directly related to the stability of equipment operation and the service life of the jaw plate. When installing a new jaw plate, ensuring smooth contact with the machine surface (moving jaw body or fixed jaw frame front wall) is a key step in avoiding early wear, fracture, and other issues. This article introduces the specific operational points to ensure smooth contact from the aspects of installation preparation, fixing method, and gap control.

1、 Preparation work before installation

Cleaning contact surfaces: Before installation, the contact surfaces between the fixed jaw plate and the front wall of the frame, and between the movable jaw plate and the movable jaw body must be thoroughly cleaned to ensure that there are no debris, oil stains, or rust. Residual material particles or casting burrs on the contact surface can cause local suspension of the jaw plate after installation, resulting in stress concentration when subjected to force.

Check the flatness of the contact surface: Inspect the installation base of the frame and movable jaw to ensure that their surfaces are flat. If there are obvious protrusions or indentations, they need to be treated before installation.

2、 Key operating points during installation process

Selection of cushion material: According to data, the newly installed jaw plate needs to be firmly fixed, and it should be in smooth contact with the surface of the machine during installation. A layer of material with good plasticity can be placed between the jaw plate and the surface of the machine. This approach helps to fill micro unevenness and make the contact more uniform.

Selection and operation of fixed methods:

The fixation of the jaw plate usually adopts two methods: bolt fixation or wedge fixation:

Bolt fixation: High strength bolts are used, and anti loosening washers need to be installed. When tightening, the sequence should be symmetrical and the force should be evenly applied to avoid excessive tightening on one side causing the jaw plate to deflect.

Wedge block fixation: Ensure that the wedge is tight to prevent the jaw plate from loosening during the crushing process.

Maintaining parallelism: When assembling the jaw plate, it is necessary to firmly fix the jaw plate on the moving and fixed jaws, and maintain the same parallelism between the moving and fixed jaws to avoid wear or breakage caused by relative sliding between the jaw plate and the moving and fixed jaws during operation.

3、 Gap control and inspection standards

The uniformity of contact between the jaw plate and the supporting surface has clear acceptance criteria to follow. According to the national standard "Code for Quality Acceptance of Installation Engineering in Nonferrous Metal Mines" (GB50961-2014), the contact between the jaw plate and the supporting surface should be uniform, and the gap should meet the following requirements:

Double pendulum jaw crusher: should not exceed 3mm

Simple swing jaw crusher: should not exceed 2mm

This regulation is clearly stated in the provisions of national standards and referenced in relevant equipment installation technical data. There is also information based on the maximum edge length of the jaw plate, requiring a gap of no more than 3.0mm/1000mm and a gap of no more than 0.5mm, which can be used as a reference for practical operation.

The inspection method usually adopts coloring method or lead pressing method for inspection. The coloring method involves applying a display agent on the supporting surface, pressing the jaw plate onto it, and observing the distribution of contact points; The lead pressing method is to place lead wires between the contact surfaces, tighten them, and measure the thickness change of the lead wires to calculate the gap size.

4、 The adoption of anti loosening measures

During the operation of the jaw crusher, there is a significant direct force between the material and the jaw plate, especially when crushing materials with high hardness, which can cause bolt vibration and nut loosening during the installation of the jaw plate. This situation cannot be completely solved by simply tightening the nut.

To address this issue, the following measures can be taken:

Spring anti loosening device: a bolt anti loosening and self tightening device made of springs, consisting of an inner spring cover, an outer spring, and a spring cover. Thread this device onto the bolt and tighten the nut. As the spring is compressed by the nut to a certain extent, it produces an anti vibration effect. The loosening force of the bolt generated by the crushing force is automatically compensated by the tension force of the spring.

Installing springs on the fixed bolts can improve the anti loosening and vibration reduction ability of the jaw plate fixing bolts, and extend the service life of the jaw plate. This method has been applied in many fields and has a positive effect on maintaining long-term stable contact between the jaw plate and the supporting surface.

5、 Inspection after installation

After the installation of the jaw plate is completed, the following checks should be carried out:

Fit inspection: After installation, check whether the jaw plate and contact surface are straight, and whether the gap meets the requirements of the equipment technical documents. Use a feeler gauge to measure the gap between the jaw plate and the supporting surface at multiple locations to ensure it is within the specified range.

Fastener re inspection: Conduct a torque check on all fastening bolts to confirm that they have reached the specified pre tightening force.

VI. Conclusion

When installing the new jaw plate, ensure smooth contact with the machine surface by starting from the following aspects:

Thoroughly clean the contact surface and check the flatness of the base surface before installation;

During installation, consideration can be given to using plastic cushioning materials, maintaining parallelism between the movable and fixed jaw plates, and adopting a reasonable tightening sequence;

After installation, check the clearance according to national standards. The clearance of the double pendulum jaw crusher should not exceed 3mm, and the clearance of the simple pendulum crusher should not exceed 2mm;

Anti loosening measures can use spring anti loosening devices to reduce loosening caused by working vibrations.

Through the above measures, the contact uniformity requirements between the jaw plate and the supporting surface can be achieved, providing guarantees for the stable operation of the equipment and the normal service life of the jaw plate.