We have collected the terms most frequently used in crushing and screening plants and the mining machinery industry, with short and technically accurate definitions. Where a term has a matching item in the CSP Engineering catalogue, we have linked to the related spare parts page.
What Is a Pitman?
The pitman (pitman arm) is the main body part of a jaw crusher that converts the rotary motion of the eccentric shaft into the swinging (crushing) motion of the movable jaw. The upper end of the pitman is mounted on the eccentric shaft, while the lower end is supported against the frame through the toggle plate. The toggle plate is deliberately designed to break under overload, protecting the far more expensive pitman and jaw. More about pitman spare parts.
What Is a Toggle Plate?
The toggle plate is the safety part of a jaw crusher that connects the pitman to the frame and is also used in setting the jaw opening. When an uncrushable object (such as a piece of metal) enters the crusher, the toggle plate is the part intended to fail first, so that the much more expensive pitman and jaw plates are not damaged. Read our toggle plate guide.
What Is an Eccentric Bushing?
The eccentric bushing is a cylindrical bearing part located between the eccentric and the main frame or shaft in cone and jaw crushers. It supports the rotating motion and takes the wear instead of the shaft. It requires regular lubrication and periodic inspection; excessive clearance leads to vibration and early failure. Eccentric bushing details.
What Is a Rotor?
The rotor is the main rotating body of impact crushers and vertical shaft impact (VSI) crushers. It spins at high speed and either throws the material or strikes it with blow bars or hammers. An unbalanced rotor causes heavy vibration as well as bearing and shaft damage, so rotor balancing is an important part of periodic maintenance. The role of the rotor in VSI crushers.
What Is a Bunker (Hopper)?
A bunker (hopper or bin) is the funnel-shaped storage structure in a crushing and screening plant where raw material — large rock from the quarry — is held temporarily and discharged to the feeder in a controlled way. A bunker must be designed with wall angles and an outlet width that allow the material to flow without bridging or blocking.
What Is a Belt?
In crushing and screening plants the word belt is used in two different contexts: (1) V-belts / drive belts that transmit motor power to the crusher, and (2) conveyor belts that carry material from one unit to the next. Tension and wear checks on drive belts, and alignment and damage checks on conveyor belts, are part of routine maintenance.
What Is a Locking Compound?
In highly vibrating crusher connections, standard bolt tightening is often not enough. A locking compound is used to prevent loosening, and a backing compound fills the gaps between wear liners and the supporting surfaces. Applications of locking compounds.
What Is a Pulley (Drum)?
A pulley or drum is the cylindrical part around which the conveyor belt wraps. It either drives the belt (drive pulley) or guides it (tail, take-up and bend pulleys). Rubber or ceramic lagging on the pulley surface increases friction between the belt and the pulley and prevents slippage.
What Is a Drive Shaft?
The drive shaft transmits power from the motor or gearbox to the crusher rotor or eccentric shaft. Misalignment or a worn coupling is one of the most common causes of vibration and early bearing failure.
What Are a Mantle and Bowl Liner?
In cone crushers, the mantle is the wear part covering the moving inner cone, and the bowl liner (concave) covers the stationary outer bowl. The material is crushed by compression in the narrowing gap between the mantle and the bowl liner. Mantle and bowl liner guide.
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