1. What is a Jaw Crusher?

その ジョークラッシャー is also widely known as the tiger mouth crusher. It is the most popular primary coarse crushing equipment in mining, sand and gravel, construction waste recycling and building material industries. It is the indispensable first-stage crushing machine for almost all mineral crushing production lines.

1.1 Core Function

It crushes large raw ores blasted from mines, rock stones and construction waste into medium and small-sized gravels through physical squeezing force. It provides qualified feeding materials for subsequent secondary crushing equipment such as cone crushers, impact crushers, ball mills and Raymond mills.

1.2 Applicable Materials

It can crush soft, medium-hard and high-hardness materials with compressive strength below 350MPa, including:

• Hard rocks: granite, basalt, iron ore, gold ore
• Medium soft stones: limestone, bluestone, dolomite
• Recycling materials: construction waste, concrete blocks, coal gangue

1.3 Two Main Types

1. Double-toggle Jaw Crusher (Most popular) Standard model for medium and small sand plants and mineral processing plants. The movable jaw realizes swinging and vertical movement simultaneously, featuring high crushing efficiency and good discharging particle shape. Feeding size: 50mm-800mm.
2. Single-toggle Jaw Crusher (Large mine dedicated) Designed for large open-pit mines. It can handle ultra-large raw ore blocks over 1000mm, with heavy-duty body and ultra-stable running performance.

2. Main Structure of Jaw Crusher (Graphic Matching Description)

A complete jaw crusher consists of 8 core components, matching the equipment structure diagram for easy understanding:

1. Fixed Jaw Plate: Stationary wear-resistant liner fixed on the frame, equivalent to upper teeth
2. Movable Jaw Plate: Reciprocating swing wear-resistant liner, equivalent to lower teeth to squeeze raw stones
3. Eccentric Shaft: Core power component, driving the movable jaw to swing periodically
4. Flywheel & Pulley: Store rotational inertia, balance load and reduce motor power consumption
5. Toggle Plate (Thrust Plate): Transmission part and safety protection part; it will break automatically to protect main shaft once overload happens
6. Adjusting Seat & Gasket: Adjust discharge opening size to control finished stone granularity
7. Tension Spring & Tie Rod: Reset the movable jaw stably after each crushing stroke
8. Heavy Welded Frame: Main body to bear huge crushing impact force

Graphic Structure Logic: Materials fall into the crushing chamber from the top feeding inlet; stones are squeezed and crushed between fixed jaw and movable jaw; qualified finished gravels are discharged from the bottom discharge outlet.

3. Detailed Working Principle of Jaw Crusher (Step-by-Step Graphic Working Flow)

The working principle of a jaw crusher is vividly similar to human upper and lower teeth biting and crushing hard nuts. Driven by an electric motor, the movable jaw performs periodic reciprocating movement to realize continuous circulating crushing. The whole working process is divided into 4 steps:

Step 1: Power Transmission

The motor drives two flywheels via V-belts. The rotating flywheels further drive the eccentric shaft to conduct eccentric circular motion. Then the eccentric shaft pushes the movable jaw to swing forward and backward regularly, providing continuous crushing power.

Step 2: Squeezing & Crushing Stroke (Movable Jaw Closing)

When the movable jaw swings close to the fixed jaw, the inner space of the crushing chamber shrinks gradually. Large raw stones are clamped between two high-manganese steel jaw plates. Under three acting forces: squeezing, bending and splitting, raw stones break automatically when internal stress exceeds their compressive resistance limit.

Step 3: Discharging Stroke (Movable Jaw Opening)

With continuous rotation of the eccentric shaft, the movable jaw resets backward. The gap of the bottom discharge outlet becomes larger instantly. Crushed stones meeting the required size fall down from the bottom outlet by gravity automatically. Large unqualified stones stay in the upper crushing chamber, waiting for next squeezing circulation.

Step 4: Continuous Circulating Operation

The movable jaw swings 250-300 times per minute. Raw materials are fed evenly from the top inlet continuously. All stones experience multiple squeezing crushing from top to bottom inside the chamber, realizing uninterrupted 24-hour production: Feeding → Squeezing Crushing → Discharging.

4. Overload Safety Protection Principle

The toggle plate is designed as a vulnerable safety part. If unbreakable foreign matters (iron blocks, steel bars) enter the crushing chamber and cause machine blocking, the toggle plate will break firstly under sudden overload pressure. It effectively protects expensive core parts (eccentric shaft, movable jaw) from severe damage, avoiding major machine failure.

5. Discharge Size Adjustment Method

Users can change the gap of bottom discharge outlet by increasing or decreasing steel gaskets at the rear adjusting seat:

• Add more gaskets → Smaller discharge opening → Finer finished gravel
• Reduce gaskets → Larger discharge opening → Coarser finished gravel

6. Advantages & Disadvantages of Jaw Crusher

6.1 Advantages

1. Large feeding inlet, suitable for ultra-large raw ore blocks; irreplaceable primary crushing equipment
2. Solid and simple structure, low failure rate; wear parts are cheap and easy to replace
3. Strong anti-blocking performance, good adaptability for wet and muddy materials
4. Small floor space, low civil construction cost, suitable for fixed crushing plant and mobile crushing station

6.2 Disadvantages

1. Intermittent working mode, lower hourly output than continuous cone crushers
2. More flaky finished particles; need matching impact crusher or cone crusher for secondary shaping
3. Relatively high vibration and noise during operation, need shock-proof foundation

7. Matching Production Line Process

Standard Complete Crushing Line: Vibrating Feeder + Jaw Crusher (Primary Coarse Crushing) + Cone Crusher/Impact Crusher (Secondary Fine Crushing) + Vibrating Screen