Jaw Crushers make some of the main types of primary crushers in mining or ore processing plants. Jaw crushers are amongst the most popular types of crushers used in the Industries today. They use compression to break the materials making them suitable for most materials.
There are two common types of Jaw Crushers available for sale in Kenya. They can either be single- toggle jaw crushers or double -toggle jaw crushers. The double toggle has its movable jaw being driven by an eccentric shaft. This shaft moves the rear and front toggles up and down resulting in the jaws closing at the downstroke and opening on the upstroke with each revolution. A single toggle crusher is also known as an overhead eccentric crusher. The eccentric in this crusher is usually integrated in the swing jaw plate. The swing plate moves up and down as the flywheel is rotated by the motor.
A jaw crusher is made to mimic the movement of an animal's jaw. The jaw crusher has two jaws that are placed in a V shaped design with a wide space at the top and a narrow one at the bottom where the crushed material is discharged. The moveable jaw compresses the material as it moves down the crushing chamber by pressing it against the stationary jaw. The moveable jaw has maximum movement at the top of the crushing chamber and minimum movement down at the discharge point.
The motion of the jaws is not as simple as up and down movement. It is a complex movement because the moveable jaw has both vertical and horizontal motion at all points along the crushing chamber. This kind of movement allows for the rocks to be reduced in size as they move down the chamber. At the discharge point the material must have attained the required size to be let through otherwise the rubbing motion between the material and the stationary jaw continues until the required size is achieved.
The single toggle type of jaw crusher is the most common jaw crusher of the two types. This is because it is highly affordable, has a very good capacity, it is lightweight and has a simple mechanism. Having a simple mechanism makes repairs and maintenance easy. Since it's highly lightweight it can be used for portable crushing rigs. It is also suitable for single stage mining and other such operations that need an affordable crusher.
Besides being highly preferred for these reasons, a single toggle jaw crusher is not very effective especially compared to the gyratory crusher. Also, due to the sliding motion between the stationary jaw plates and material, the jaw plate wears out quickly. This sliding motion happens so much down the crushing chamber close to the discharge point. The single toggle jaw crusher is not very effective for for highly abrasive, tough or hard rocks. For these kind of materials, a double toggle jaw crusher is preferred.