The Jaw Crusher is a common crushing equipment used in sand and gravel plants and consists of a frame, jaws and side guards, transmission components, regulating device, flywheel, lubrication device, etc.
1. Luggage frame
The frame is a four-walled rigid frame with upper and lower openings to support the eccentric shaft and withstand the reaction force of the crushing material. It requires sufficient strength and rigidity. It is generally cast in cast steel as a whole, but small machines can also use high quality cast iron instead of cast steel. The frame of the main machine needs to be cast in sections and then bolted firmly into a single unit, making the casting process complex. The frame of a home-made small jaw crusher can also be welded with thick steel plates, but the rigidity is poor.
2. Jaws and side guards
Both the fixed jaw and the movable jaw consist of a jaw seat and a jaw plate, which is the working part and is fixed to the jaw seat by means of bolts and wedges. The fixed jaw bed is the front wall of the frame, and the movable jaw bed hangs on the circumference, which needs sufficient strength and rigidity to withstand the crushing reaction, so it is mostly cast steel or cast iron parts.
3. Transmission parts
The eccentric shaft is the main shaft of the crusher and is made of high carbon steel. The eccentric parts should be finish machined and heat treated, and the bearing bushings should be cast in pasteurised alloy. The eccentric shaft is equipped with a pulley at one end and a flywheel at the other.
4. Butterfly device
Adjustment devices are wedge type, pad type and hydraulic type. The wedge type is generally used and consists of a front and rear wedge. The front wedge can be moved back and forth to resist the rear push plate. The rear wedge is the adjusting wedge and can be moved up and down. The bevels of the two wedges are reversed to fit together and the screw moves the rear wedge up and down to adjust the size of the discharge opening. Adjustment of the small jaw crusher discharge opening is achieved by increasing or decreasing the number of spacers between the rear thrust plate bracket and the frame.
5. Flywheel
The flywheel of the jaw crusher is used to store the energy from the idling stroke of the jaws, which is then used for industrial forming to even out the working consistency of the machine. The pulley also acts as a flywheel. Flywheels are usually made of cast iron or cast steel, and mini-computers usually have a one-piece flywheel. Care is taken in the manufacture and installation of flywheels to ensure that they are statically balanced.
6. Lubrication devices
Eccentric shaft bearings are usually lubricated by centralised circulation. Normally, the bearing surfaces of the main shaft and thrust plate are supplied with grease by means of a manual grease gun. The swing angle of the moving jaw is so small that it is difficult to lubricate between the main shaft and the shaft shank. Several axial oil grooves are often cut in the bottom of the shaft shank, with a ring in the middle connected to the groove, and then lubricated by forcing dry grease through an oil pump.
