Jaw Crusher is a machine that is mostly used in the primary and secondary process of crushing. The main objective of this machine is to crush the large blocks of hard and abrasive materials.
This article explains the complete working principle of jaw crushers. Besides, we will also explain the complete main components of the jaw crusher. What are the main parts and parameters of the jaw crusher? So let’s get started…
How Does Jaw Crusher Work?
The working mechanism of the jaw crusher is very simple and straightforward. A jaw crusher comes with two powerful jaws in which one is fixed and the other one can move. Its working principle is based on the reciprocating movement of the movable jaw. The moveable jaw compresses and crushes everything including ore or rock between itself and the fixed jaw.
The movement of the movable jaw is back and forward against the fixed jaw and break the material between the two jaws into smaller pieces. The crushed material is released from the crusher at the bottom when the moving jaw moves back from the fixed jaw.
What Are The Main Parts of Jaw Crushers?
Jaws play a key role in a jaw crusher. However, the real heart of the jaw crusher and its components are the pitman, the toggle plates, and flywheel. These are the main parts that provide a sufficient amount of energy to break the rocks. Let’s take a brief overview that how these parts work together and make a crushing cycle:
Below are the 10 most incredible parts of jaw crushers:
- Drive Flywheel
The flywheel is the heart of the jaw crusher. The main objective of the flywheel is to generate a sufficient amount of energy in the form of motion. An electric motor provides enough momentum to the flywheel. Then, it initiates the crushing cycle. One the process is started, the motor will have to provide the energy only necessary to propel the flywheel.
- Cheek Plate
These plates are made of high manganese steel casting. In addition to this, some other materials are also used in its construction such as advanced composite material. And, super high and ultra-strong manganese. You can easily replace these places if necessary. There are two types of cheek plates: upper cheek plate and lower cheek plate.
These are one of the most common types of drive belts used for power transmission. The primary function of V-belts is to transmit power from the primary unit such as a motor to the shaft.
- Drive Motor
It is another most important part of a jaw crusher. This electric motor drives a reducer sheave. The one side of the reducer sheave is an eccentric shaft and the other end of the shaft is a flywheel.
- Motor Stand
As the name suggests, the motor stand gives support to the drive motor. So it is a stand where an electric motor sits for proper functioning.
- Eccentric Shaft
The eccentric shaft which is commonly known as pitman generates the crushing action. It is a shaft with a portion of its length offset from the rest of the shaft. The portion travels in a greater arc when the shaft revolves. The manufacturers generate motion by attaching a bearing system i.e. pitman bearing and cup. So the generating motion direction is usually up and down.
- Toggle Plate
Depending on the type of jaw crusher, the toggle plates play an important role in the crushing process. The toggle plates are comprised of two steel plates and the manufacturers combine these plates with the help of bolts. These bolts are commonly known as Shear Bolts because these bolts are famous for shear strength. If crusher can’t crush something accidentally gets into the crushing chamber. Then, these bolts shear off when the jaw hits the unbreakable material. Therefore, it will prevent damaging the crusher.
- Swing Jaw
All jaw crusher comes with two jaws. One of them is moving or swing jaw. This jaw moves back and forward against the fixed jaw to break everything between them into smaller pieces. You can consider it as a lower jaw in humans.
- Fixed Jaw
As the name suggests, the fixed jaw can’t move. The moving jaw only moves back and forth to crush different things. You can consider it a supporting jaw that has a striking resemblance to the upper jaw in humans.
This is a part that collects the crushing piece of an object. When the swing jaw moves back, the crushed objects are dropped in this part.
Different Jaw Crusher Parameters
Here are some important parameters of jaw crusher given below:
- Gap Width
- The maximum feed size is between 80% and 90% of the inlet width.
- Crushing area length is almost double from the gap width.
- Crushing area width varies from 1.3 to 3 times based on the gap width.
- L-Max is a far side jaw opening.
- L-Min is near side jaw opening.
- Stroke is the minimum and maximum movability of the lower end of the jaw.
- The size Reduction ratio is a gap width to the near side jaw opening. It can vary between 1/3 and 1/9. However, primary crushers have a 1/3 size reduction ratio and the size reduction ratio in secondary crushers is ¼ usually.
The angle between the two jaws is one of the most incredible parameters. This parameter is most commonly known as the nip angle. This is the angle that decides the size of the material passes through the crusher inlet to be crushed. Therefore, this angle is very important that helps the crusher to grip the object without slipping. So this angle depends on the size, frangibility, and the hardness of the material. You can’t select the object that is too small or too large. The nip angle in secondary crushers is greater than the angel in primary crushers. Generally, the value of the angle range from 18 to 24 degrees in primary and 22 to 28 degrees in secondary crushers. The maximum value of nip can be 33 degrees.