Mechanical principle teaching and demonstrating model

Provided is a mechanical principle teaching and demonstrating model which comprises a driving belt pulley, a driven belt pulley, a driving sprocket, a driven sprocket, a first gear, a second gear, a third gear, a fourth gear, and a fifth gear which are in successive transmission connection. The fifth gear is in transmission connection with a crankshaft connecting rod mechanism. The mechanical principle teaching and demonstrating model is novel in design, simple in structure, easy in manipulation, and may demonstrate the operating principles of belt transmission, chain transmission, gear transmission, and crankshaft connecting rod mechanism. The mechanical principle lesson demonstrating model demonstrates the operating principles of belt transmission, chain transmission, gear transmission, and crankshaft connecting rod mechanism, has remarkable demonstration effect and a good visualized property, greatly improves learning initiative of students, has an effect of saving time and good practicality, and is liable to popularization and application.